Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has...

44
FEATURING: MIT Bates • Nuclear Symmetry Energy • Nuclear Physics at γELBE 10619127(2017)27(4) N uclear P hysics N ews International Volume 27, Issue 4 October–December 2017

Transcript of Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has...

Page 1: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

FEATURING:MIT Bates • Nuclear Symmetry Energy • Nuclear Physics at γELBE

10619127(2017)27(4)

Nuclear Physics NewsInternational

Volume 27, Issue 4October–December 2017

Page 2: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

Read Every Issue

Laboratory Portraits

Facilities and

Methods

Meeting Reports

News and

Views

Upcoming Events

Page 3: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

Vol. 27, No. 4, 2017, Nuclear Physics News 1

Editor: Gabriele-Elisabeth Körner

Editorial Board Maria José Garcia Borge, Madrid (Chair) Eugenio Nappi, Bari Rick Casten, Yale Klaus Peters, Darmstadt

Jens Dilling, Vancouver Hermann Rothard, CaenRolf-Dietmar Herzberg, Liverpool Hideyuki Sakai, Tokyo

Yu-Gang Ma, Shanghai Calin Ur, Bucharest Richard Milner, MIT

Editorial Offi ce: Physikdepartment, E12, Technische Universitat München,85748 Garching, Germany, Tel: +49 89 2891 2293, +49 172 89 15011, Fax: +49 89 2891 2298,

E-mail: [email protected]

Correspondents (from countries not covered by the Editorial Board and NuPECC)Argentina: O. Civitaresse, La Plata; Australia: A. W. Thomas, Adelaide; Brasil: M. Hussein, São Paulo; India: D. K. Avasthi, New Delhi; Israel: N. Auerbach, Tel Aviv; Mexico: E. Padilla-Rodal, Mexico DF; Russia: Yu. Novikov, St. Petersburg; Serbia: S. Jokic, Belgrade; South Africa: S. Mullins, Cape Town.

Nuclear Physics NewsVolume 27/No. 4

Nuclear Physics News is published on behalf of the Nuclear Physics European Collaboration Committee (NuPECC), an Expert Committee of the European Science Foundation, with colleagues from Europe, America, and Asia.

Nuclear Physics News ISSN 1061-9127

Advertising ManagerMaureen M. WilliamsPO Box 449Point Pleasant, PA 18950, USATel: +1 623 544 1698E-mail: [email protected]

Circulation and SubscriptionsTaylor & Francis Group, LLC530 Walnut StreetSuite 850Philadelphia, PA 19106, USATel: +1 215 625 8900Fax: +1 215 207 0050

Copyright © 2017 Taylor & Francis Group, LLC. Reproduction without permission is prohibited.All rights reserved. The opinions expressed in NPN are not necessarily those of the editors or publishers. The views expressed here do not represent the views and policies of NuPECC except where explicitly identifi ed.

SubscriptionsNuclear Physics News is supplied free of charge to nuclear physicists from contributing countries upon request. In addition, the following subscriptions are available:

Volume 27 (2017), 4 issuesPersonal: $146 USD, £88 GBP, €120 EuroInstitution: $1,223 USD, £737 GBP, €975 Euro

Page 4: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

2 Nuclear Physics News, Vol. 27, No. 4, 2017

NuclearPhysicsNews

Cover Illustration: The toroidal magnet for the Qweak experiment undergoing testing at the Bates Laboratory at MIT. The magnet and support frame were designed and tested at the Bates Laboratory before being shipped to Jefferson Laboratory in Virginia. See the article starting on page ??.

Volume 27/No. 4

Contents

EditorialThe Global Nuclear Physics Community

by Richard G. Milner .................................................................................................................................................... 3

Laboratory PortraitThe MIT Bates Laboratory

by Robert Redwine ........................................................................................................................................................ 4

Feature ArticlesNuclear Symmetry Energy Extracted from Laboratory Experiments

by Bao-An Li ................................................................................................................................................................. 7Ion and Neutron Beams Discover New Facts from History

by A. Macková, J. Kučera, J. Kameník, V. Havránek, and K. Kranda .......................................................................... 12

Facilities and MethodsThe Institute for Nuclear and Radiation Physics at the University of Leuven

by Thomas Elias Cocolios, Mark Huyse, and André Vantomme ................................................................................... 18Nuclear-Physics Experiments at the Bremsstrahlung Facility γELBE

by Ronald Schwengner and Andreas Wagner ............................................................................................................... 23

Meeting ReportsThe International Conference on Isospin, Structure, Reactions, and Energy of Symmetry: Istros 2017

by Martin Veselsky and Martin Venhart ........................................................................................................................ 27NPA8: The 8th Nuclear Physics in Astrophysics International Conference

by C. Spitaleri, M. Lattuada, and M. La Cognata ........................................................................................................ 29Strangeness in Quark Matter

by André Mischke ......................................................................................................................................................... 31

News and ViewsOn the Development of Nuclear Physics in Cuba

by Fidel Castro Díaz-Balart .......................................................................................................................................... 33

In MemoriamIn Memoriam: Arthur Kerman (1929–2017)

by Ernest J. Moniz ......................................................................................................................................................... 38In Memoriam: Peter Paul (1933–2017)

by Peter Braun-Munzinger, Volker Metag, and Johanna Stachel ................................................................................. 39In Memoriam: Adriaan van der Woude (1930–2017)

by Sytze Brandenburg, Muhsin N. Harakeh, and Rolf H. Siemssen .............................................................................. 40

Calendar..................................................................................................................................... Inside back cover

Update

Page 5: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

editorial

Vol. 27, No. 4, 2017, Nuclear Physics News 3

Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens of specific nations and typically receive funding in support of our research from the taxes paid by the citizens of our home country. However, scientific research is conducted as an interna-tional endeavor where the expectation is that nationalism is irrelevant and that free flow of people and ideas is facilitated between the continents and across the oceans.

Recently, democratic elections in the United Kingdom and the United States have given expression to sig-nificant anti-immigrant sentiment in these countries, which have long pro-vided world leadership in scientific research and education. Xenophobia is also to be found in other countries. The rise of isolationism confronts “the modern interconnected world in which goods, people and ideas have contempt for borders” [1]. Here, I argue that the global nuclear phys-ics community has played and will continue to play a significant role in countering isolationism and in main-taining the free flow of people and ideas around the world.

In 2017, nuclear physics is an intel-lectually vibrant field with direct and important applications to society. Ex-perimental research is conducted at all scales from table-top experimentation involving a handful of physicists to the Large Hadron Collider with thousands of physicists taking part from coun-tries spread across the globe. Theoreti-cal nuclear physicists use the world’s most powerful computers to carry out state-of-the art sophisticated calcula-tions. There are major new nuclear

physics facilities under construction and in planning worldwide. Nuclear physics research is truly an interna-tional endeavor with a bright future.

Nuclear physics is especially rel-evant to confronting some of the most pressing issues facing humanity. Nu-clear weapons control, carbon-free en-ergy production on a large scale, coun-terterrorism, and nuclear medicine are all areas where nuclear physicists are playing a leadership role. Our interna-tional community provides the frame-work where free exchange of ideas concerning these politically sensitive subjects can take place. Further, nu-clear physicists serve in governments worldwide in leadership positions that address these critical issues.

The international scientific com-munity facilitates free movement of people. Many of us are immigrants—born on one continent and following our professional careers on another. The United States has been particu-larly generous since the mid-20th cen-tury in welcoming talented foreigners from around the world to a free third-level education at some of the best re-search universities in the world. This wise approach has brought great ben-efit to the United States. For example, of the approx. 100 U.S. Physics Nobel Prize winners, 30% were born outside the United States. In Europe, the Eu-ropean Union has created an excellent network system of funding science that promotes transnational collabora-tion and again has benefited the citi-zens and economies of the countries in the European Union. Of course, Europe has also created CERN, the world’s leading high-energy physics laboratory and a much-admired, suc-

cessful model for large-scale interna-tional scientific collaboration.

It is essential that our international nuclear physics community redouble its efforts to maintain the free flow of people and ideas. We must seek to enhance our prominent and successful international scientific meetings. We should take particular care to strive that nobody is excluded because of visa restrictions. Further, enhancing the careers of our young nuclear phys-ics colleagues worldwide must be a high priority, as they constitute the fu-ture of our field. When opportunities arise to participate in outreach to so-ciety, we should not hesitate to accept them. Continuing to work as a potent and coherent international community confronting important and fundamen-tal scientific questions and engaged with unique expertise in addressing critical issues facing humanity, nu-clear physicists around the world con-stitute an important bulwark against isolationism.

Reference1. E. Robinson, The Washington Post,

July 6, 2017.

RichaRd G. MilneR

Laboratory for Nuclear Science, MIT, Cambridge, Massachusetts, USA

The Global Nuclear Physics Community

The views expressed here do not represent the views and policies of NuPECC except where explicitly identified.

Page 6: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

laboratory portrait

4 Nuclear Physics News, Vol. 27, No. 4, 2017

The Bates Laboratory, operated by the Massachusetts Institute of Tech-nology (MIT), is a valuable techno-logical and computing resource for the international nuclear physics commu-nity and beyond. The laboratory was originally authorized for construction in 1967 and began experiments us-ing high-current beams of electrons in 1974. It underwent several important upgrades (to detectors and to the beam energy, time structure, and polariza-tion) before completing its mission as a major international accelerator user facility in 2005. See, for example, the article authored by Richard Milner in Nuclear Physics News in 1999 [1]. Re-search directions that were pioneered at Bates include very high-resolution electron-nucleus scattering using En-ergy Loss Spectrometry, and the use of parity-violating electron scattering to study important problems in nuclear physics and in Beyond-the-Standard-Model tests.

The Bates Laboratory is located in Middleton, Massachusetts, which is about 35 km north of the main MIT campus in Cambridge. When the labo-ratory was established it was clear that there would not be enough space for such a linear-accelerator-based facil-ity in the urban environment of Cam-bridge. However, it was also realized that it was very important that close connections be maintained between the Bates Laboratory and the main campus. That in fact has been the case, and continues to this day.

When the Bates Laboratory com-pleted its mission as a user facility in 2005, it was decided by MIT and by the U.S. Department of Energy (DOE) to maintain important techni-cal capabilities at Bates for the use of researchers in nuclear physics and other fields. These capabilities include

unique research-related and radiation-shielded space, and most importantly, a highly trained staff accustomed to supporting experimental efforts in nu-clear and particle physics. The Bates staff has expertise in accelerator phys-ics, magnet design, cryogenics, digital and analog electronics, and polarized external and internal targets. The tech-nical staff consists of a combination of scientists, engineers, and technicians.

Since 2005 the Bates Laboratory at MIT has supported a variety of proj-ects in nuclear and particle physics. Typically the Bates staff gets involved in the early stages of project planning, when technical choices are still be-ing made, and when testing and pro-totyping are beginning. As a project matures it is often the case that major pieces of equipment are designed and constructed at the Bates Laboratory, using the specialized equipment and space at the laboratory. Delivery of the equipment to the location of the exper-iment follows final testing at Bates.

The following sections are exam-ples of the projects that the Bates Lab-oratory has provided major support to.

Design and Construction of the Toroidal Spectrometer Magnet for the Qweak Experiment at Jefferson Laboratory (Virginia, USA)

The Qweak experiment was per-formed to provide a precision mea-surement of parity-violating electron scattering on the proton at very low Q2 and forward angles to challenge predictions of the Standard Model and to search for new physics. This experi-ment was designed to carry out the first precision measurement of the proton’s weak charge, QP

W = 1 – 4sin2qW. The Standard Model of electro-weak in-teractions makes a firm prediction for QP

W, based on the running of the weak

mixing angle sin2qW from the Z0 pole down to low energies.

The Bates Laboratory was respon-sible for the design, procurement, assembly, and testing of the toroidal magnet (QTOR) and support frame used for the Qweak experiment (see the figure on the cover of this is-sue). Bates also designed, procured, and tested the power supply (9000A, 200V) for the toroid. The toroid was field mapped at the Bates Laboratory, then disassembled and transported to Jefferson Laboratory for the ex-periment. A Compton polarimeter to measure the polarization of the elec-tron beam was also designed and con-structed at Bates and delivered to Jef-ferson Laboratory for this experiment.

The Qweak collaboration recently released results from the analysis of the complete data set acquired, and the precision achieved matches the design precision.

Design, Construction, and Testing of the Intermediate Silicon Tracker for the STAR Experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory (New York, USA)

The Solenoidal Tracker at RHIC (STAR) collaboration recently up-graded their tracking capabilities with installation of the Heavy Flavor Tracker, which included a new Inter-mediate Silicon Tracker (IST). The goal of the STAR collaboration at RHIC is to investigate fundamental properties of the new state of strongly interacting matter produced in rela-tivistic heavy ion collisions, and to provide fundamental studies of the nucleon spin structure and dynamics in high-energy polarized proton–pro-ton collisions. A critical factor in ac-complishing this goal is the ability to

The MIT Bates Laboratory

Page 7: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

laboratory portrait

Vol. 27, No. 4, 2017, Nuclear Physics News 5

directly reconstruct charm and beauty decays as well as flavor-tagged jets to allow a precise measurement of the spectra, yields, and flow of open charm and beauty production. The re-construction of open charm and beauty production in proton–proton colli-sions and for low-multiplicity events in relativistic heavy-ion collisions in particular required a new intermediate tracking system together with the ex-isting STAR silicon-strip detector and the STAR time projection chamber.

The Intermediate Silicon Tracker replaced the STAR Silicon Vertex Tracker, which was based on silicon drift detectors. The IST was designed, constructed, and tested at the Bates Laboratory. Bates staff worked closely with Brookhaven National Labora-tory and Lawrence Berkeley National Laboratory (California, USA) staff to produce 24 kapton hybrid staves on carbon fiber supports. Bates was also responsible for fabricating the cooling system for the detectors, which used a

Dupont-engineered cooling medium. The IST was installed in STAR at RHIC in 2013 and provided excellent tracking data for several years. The IST is shown in Figure 1 before instal-lation.

Design, Construction, and Optimization of a High-Intensity Polarized Electron Source for use in a Future Electron-Ion Collider

The next-generation major accel-erator for nuclear physics research in the United States has been defined by the community to be an Electron-Ion Collider. It is notable that Bates played a leadership role in the first accelerator design for an Electron-Ion Collider, a ring-ring concept using the RHIC complex [2]. For some designs of an Electron-Ion Collider, the phys-ics program will depend significantly on the availability of high-intensity (on the order of 50 mA average) polar-ized electron beams. Current polarized electron sources have achieved aver-age currents of only about 1 mA. So a very significant increase in intensity is needed.

A team at the Bates Laboratory has for several years been pursuing a project to demonstrate a high-inten-sity polarized electron source (Figure 2). The basic idea is that a polarized beam from a laser produces polar-ized photo-electrons when it strikes a GaAs crystal. Three main features are implemented to achieve very high in-tensity: the cathode is actively cooled to avoid its overheating by the intense laser beam; the cathode active area is very large to reduce ion bombardment effects; and, since the ion bombard-ment mostly affects the central area of the cathode, the laser beam is ring shaped, leaving the most vulnerable central area of the cathode unused. Significant progress has been made in implementing these features, and we expect that we will soon be able

to determine if this general approach will produce the required intensities of polarized electrons.

Testing and Optimization of an Atomic Beam Source of Polarized 3He for use in an Experiment to Search for a Non-Zero Value of the Electric Dipole Moment of the Neutron

The search for a non-zero value of the neutron electric dipole moment is one of the most high-profile experi-ments in physics today. If the neutron does have a measureable electric di-pole moment, it would be a direct indi-cation of physics beyond the Standard Model. Almost all extensions to the Standard Model predict a value of the nEDM only one to two orders of mag-nitude below the current experimental upper limit. Current efforts to improve the limit are using so-called “co-mag-netometers” to eliminate the effects of non-uniformities in the small mag-netic field in which the polarized neu-trons precess. An experiment planned for the Spallation Neutron Source at

Figure 1. The intermediate silicon tracker prior to installation in STAR at RHIC.

Figure 2. The high-intensity polarized electron source under development at the Bates Laboratory.

Figure 3. The atomic beam source of polarized 3He under assessment at the Bates Laboratory.

Page 8: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

laboratory portrait

6 Nuclear Physics News, Vol. 27, No. 4, 2017

Oak Ridge National Laboratory (Ten-nessee, USA) will use polarized 3He as its “co-magnetometer”.

At the Bates Laboratory, a team is assessing the suitability of an Atomic Beam Source (ABS) of polarized 3He that was originally constructed at Los Alamos National Laboratory (New Mexico, USA). A picture of this appa-ratus is shown in Figure 3. The most crucial assessment concerns the fl ux and divergence of polarized 3He that the ABS produces. The team will also convert the ABS so that it produces a vertical beam, not a horizontal beam. This is necessary for it to be of use in the Oak Ridge experiment. We expect that this project will be complete in roughly a year.

Design of a DIRC Capability for the GlueX Detector at Jefferson Laboratory

The GlueX project at the Jefferson Laboratory has as its goal the discov-ery of new QCD states that are pre-dicted by various models. A recent planned upgrade to the GlueX detec-tor involves the addition of a Detec-tion of Internally Refl ected Cherenkov light (DIRC) capability, especially to enhance the ability to separate pions from kaons. The radiator for the DIRC uses four fi ve-meter long “bar boxes,” each containing twelve fused silica bars. These bar boxes are recycled from the BaBar detector that was built previously at SLAC.

The Bates Laboratory team is help-ing with the DIRC construction by de-signing and building optical boxes that

will transport light from the bar boxes to the photon detector plane. This light will then be utilized to image the Che-renkov radiation emitted from the bar boxes. Figure 4 shows the design of the DIRC with the optical boxes.

ConclusionThe examples described above

hopefully give the reader an idea of the capabilities of the Bates Laboratory in supporting a variety of experiments in nuclear and particle physics. The ex-amples are certainly not exhaustive, and new capabilities are regularly be-ing added.

An important addition to the ca-pabilities at the Bates Laboratory oc-curred in 2009, when MIT made the decision to locate a large High-Per-formance Computing Facility at the laboratory. This entailed repurposing space that had previously been used as a large “counting house” where scien-tists monitored equipment and data as nuclear physics experiments were un-derway at Bates. Cooling capabilities for the computer racks were installed, as this is a major need for such mod-

ern computing facilities. In addition, a high-speed (10 Gb/s, since upgraded to 100 Gb/s) link to the main MIT campus was implemented, which ef-fectively provides a high-speed link to many sites worldwide. Currently the facility has 71 racks for processors. Each of these racks can provide up to 10 kW of power for computing and cooling. The Bates site itself has about 10 MW of electrical capacity. The High-Performance Computing Facil-ity is evolving in its usage, including being part of widely shared computing resources.

The Bates Laboratory at MIT is a rather unique capability for the nu-clear physics community, in that it is a resource of highly trained and expe-rienced scientists, engineers, and tech-nicians who are available to support a wide range of projects. The Labora-tory welcomes inquiries concerning possible collaborations.

References1. R. G. Milner, Nucl. Phys. News 9(2)

(1999) 4.2. M. Farkhondeh and V. Ptitsyn (eds,),

BNL report C-A/AP/142, March 2004.

ROBERT REDWINE

MIT, Cambridge, Massachusetts, USA

Figure 4. A computer automated de-sign (CAD) of the planned GlueX DIRC with optical boxes.

BesuretochecktheCalendarforupcomingeventsofinteresttonuclearphysicists.

Page 9: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

feature article

Vol. 27, No. 4, 2017, Nuclear Physics News 7

Nuclear Symmetry Energy Extracted fromLaboratory ExperimentsBAO-AN LIDepartment of Physics and Astronomy, Texas A&M University–Commerce,Commerce, Texas, USA

IntroductionThe Equation of State (EOS) of uniform neutron-rich

nucleonic matter of isospin asymmetry δ = (ρn − ρp)/ρand density ρ can be expressed in terms of the energy pernucleon E(ρ,δ ) within the parabolic approximation as

E(ρ,δ ) = E(ρ,0)+Esym(ρ)δ 2 +o(δ 4) (1)

where Esym(ρ) = 1/2(∂ 2E(ρ,δ )/∂δ 2)δ=0 ≈ E(ρ,1) −E(ρ,0) is the symmetry energy of asymmetric nuclear mat-ter (ANM). It is approximately the energy cost of convert-ing symmetric nuclear matter (SNM, with equal numbersof protons and neutrons) into pure neutron matter (PNM).Many interesting questions including the dynamics of su-pernova explosions, heavy-ion collisions, structures of neu-tron stars and rare isotopes, frequencies, and strain ampli-tudes of gravitational waves from both isolated pulsars andcollisions involving neutron stars all depend critically onthe EOS of neutron-rich nucleonic matter. Thanks to thegreat efforts of scientists in both nuclear physics and astro-physics over the last four decades, much knowledge aboutthe EOS of SNM; that is, the E(ρ,0) term in Eq. (1), hasbeen obtained [1]. In more recent years, significant effortshave been devoted to exploring the poorly known Esym(ρ)using both terrestrial laboratory experiments and astrophys-ical observations. Essentially, all available nuclear forceshave been used to calculate the Esym(ρ) within variousmicroscopic many-body theories and/or phenomenologicalmodels. However, model predictions still vary largely atboth sub-saturation and supra-saturation densities althoughthey agree often by construction at the saturation densityρ0. Therefore, accurate experimental constraints are imper-ative for making further progresses in our understandingof the Esym(ρ). To facilitate the extraction of informationabout the Esym(ρ) from laboratory experiments, much workhas been done to find observables that are sensitive to theEsym(ρ) by studying, for instance, static properties, excita-tions, and collective motions of nuclei as well as various ob-servables of nuclear reactions. Comprehensive reviews onthe recent progress and remaining challenges in constrain-ing the Esym(ρ) can be found in the literature [2–8]. Mostimportantly, much progress has been made in constraining

the Esym(ρ) around and below ρ0 while its high densitybehavior remains rather uncertain. Combining results fromongoing and planned new laboratory experiments with ra-dioactive beams and astrophysical observations using ad-vanced X-ray observatories and gravitational wave detec-tors has the great promise of pinning down the symmetryenergy of dense neutron-rich matter in the near future.

Important but Poorly Known Physics UnderlyingNuclear Symmetry Energy

It is well known that the nucleon potential Un/p(k,ρ,δ )in ANM can be expanded up to the second order in δ as

Uτ(k,ρ,δ ) =U0(k,ρ)+ τ3 ·Usym,1(k,ρ) ·δ +Usym,2(k,ρ)

·δ 2 +O(δ 3) (2)

where τ3 = ±1 for τ = n/p and k is nucleon momen-tum. At the mean-field level, both the Bruckner theory andthe Hugenholtz-Van Hove (HVH) theorem show that theEsym(ρ) at an arbitrary density has two parts (kinetic andpotential) [9]

Esym(ρ) =13

h2k2F

2m∗0+

12

Usym,1(k,ρ) (3)

while its density slope L(ρ)≡ 3ρ(∂Esym/∂ρ) has five parts

L(ρ) =23

h̄2k2F

2m∗0− 1

6

(h̄2k3

(m∗0)

2 ·∂m∗

0∂k

)

kF

+32

Usym,1(ρ,kF)

+

(∂Usym,1

∂k

)

kF

· kF +3Usym,2(ρ,kF), (4)

where kF = (3π2ρ/2)1/3 is the nucleon Fermi momentumand m∗

0 = m/[1+ mh2kF

dU0/dk)kF ] is the nucleon isoscalareffective mass. Obviously, the Esym(ρ) and L(ρ) dependon the density and momentum dependence of both theisoscalar U0 and Usym,2 as well as the isovector Usym,1 poten-tials. While the U0 has been relatively well constrained bystudying experimental observables in heavy-ion reactions,especially various kinds of collective flow and kaon pro-duction, our current knowledge about the density and mo-mentum dependence of the Usym,1(ρ,k) and Usym,2(ρ,k) isvery poor.

Page 10: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

feature article

8 Nuclear Physics News, Vol. 27, No. 4, 2017

It is important to point out that the Esym(ρ) is closely re-lated to the neutron-proton effective mass splitting m∗

n−p ≡(m∗

n − m∗p)/m, which is a fundamental quantity having

broad impacts on many interesting issues in both nuclearphysics and astrophysics. In terms of the momentum de-pendence of the single-nucleon potential or the Esym(ρ) andL(ρ), the m∗

n−p is approximately

m∗n−p ≈

2mδh2kF

[−

∂Usym,1

∂k− kF

3∂ 2U0

∂k2 +13

∂U0

∂k

](m∗

0m

)2

≈ δEF(ρ)

[3Esym(ρ)−L(ρ)− 1

3mm∗

0EF(ρ)

](m∗

0m

)2

where EF(ρ) is the Fermi energy in SNM. Therefore, whileprobing the Esym(ρ), we are also studying the neutron-proton effective mass splitting in neutron-rich nuclear mat-ter. It is well known that the kinetic symmetry energy isdue to the Pauli blocking and the different Fermi momentaof neutrons and protons. Since the nucleon isoscalar effec-tive mass m∗

0/m ≈ 0.7 at ρ0, the kinetic symmetry energyof quasi-nucleons at ρ0 is about 43% larger than that ofthe free Fermi gas of about 12 MeV frequently used inthe literature. The potential symmetry energy is due to theisospin dependence of the strong interaction. For example,the Hartree term of the isovector potential at kF in the inter-acting Fermi gas model can be approximated by

Usym,1(kF ,ρ) =14

ρ∫[VT 1(ri j) f T 1(ri j)

−VT 0(ri j) f T 0(ri j)]d3ri j

in terms of the isosinglet (T = 0) and isotriplet (T = 1)nucleon-nucleon (NN) interactions VT 0(ri j) and VT 1(ri j),and the corresponding NN correlation functions fT 0(ri j)and fT 1(ri j), respectively. While the charge independenceof the strong interaction requires that Vnn = Vpp = Vnpin the T = 1 channel, they are not necessarily equal tothe V ′

np in the T = 0 channel. Obviously, if there is noisospin dependence in both the NN interaction and cor-relation function, then the isovector potential Usym,1 van-ishes. The momentum dependence of the isovector po-tential from the Fock term using Gogny-type finite-range,isospin-dependent interactions is often parameterized byusing different strengths of interactions between like andunlike nucleons. Indeed, microscopic many-body theoriespredicted that the potential symmetry energy is dominatedby the isosinglet interaction. It is also well known thatthe short-range correlation in the T = 0 channel is muchstronger than that in the T = 1 channel [10]. The potentialsymmetry energy thus reflects the isospin dependence ofnucleon–nucleon interactions and correlations in asymmet-ric nuclear matter.

The momentum dependence of the isoscalar and isovec-tor potential at ρ0 has been explored extensively using(p,n) charge-exchange and nucleon-nucleus elastic scatter-ings. The resulting single-nucleon potential has been usedto constrain the Esym(ρ0) and L(ρ0).

As an example, shown in Figure 1 are the kineticE1

sym(ρ0) and potential E2sym(ρ0) parts of Esym(ρ0) and the

five components [defined in Eq. (4)] of its slope L(ρ0)extracted from a recent analysis of large sets of nucleon-nucleus elastic scattering data using an optical model [11].The kinetic and potential parts of the symmetry energy fromthis analysis are approximately equal. Among the five partsof the slope parameter L(ρ0), the L4 due to the momentum-dependence of the isovector potential and the L5 fromthe second-order isoscalar potential have the largest uncer-tainties. The characteristically decreasing isovector poten-tial with increasing energy/momentum leads to a positiveneutron–proton effective mass splitting and a negative valueof L4 at ρ0. The mere fact that the L(ρ0) has five terms hav-ing different signs and physical origins indicates clearly thedifficulties of completely pinning down the Esym(ρ) evenaround the saturation density.

Given our poor knowledge about some components ofthe L(ρ), no wonder why it is so difficult to determine ac-curately the isospin dependence of the incompressibilityof ANM K(δ ) = K0 + Kτ δ 2 + O(δ 4) at ρ0 where Kτ =Ksym − 6L(ρ0) − Q0L(ρ0)/K0 in terms of the curvatureof the symmetry energy Ksym ≡ 9ρ2(∂ 2Esym(ρ)/∂ρ2)ρ0 =3[ρ∂L(ρ)/∂ρ −L(ρ)]ρ0 as well as the skewness Q0 and in-compressibility K0 of SNM at ρ0. As the Ksym involves the

Figure 1. The kinetic E1sym(ρ0) and potential E2

sym(ρ0) partsof the symmetry energy Esym(ρ0) and the five components[in the order of appearing in Eq. (4)] of its slope L(ρ0)extracted from an optical model analysis of the nucleon-nucleus elastic scattering data. Taken from Ref. [11].

Page 11: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

feature article

Vol. 27, No. 4, 2017, Nuclear Physics News 9

derivative ∂L/∂ρ , to determine its value we have to knownot only the magnitudes but also the density and momen-tum dependences of both the isoscalar and isovector nu-cleon potentials. Unfortunately, these quantities are largelyunknown both theoretically and experimentally. As a result,the current estimate of the value of Kτ =−550±100 MeVfrom analyzing many different kinds of experimental dataavailable still has a large error bar. It is also not surprisingthat some of the best models available are having troublereproducing the incompressibility of some neutron-rich nu-clei (e.g., Tin isotopes from 112Sn to 124Sn).

The decompositions of Esym(ρ) and L(ρ) in Eqs. (3) and(4) are transparent and useful for identifying the importantunderlying physics. However, they have limitations. Thereare density regions or phenomena for which correlationsbeyond the mean-field level have to be treated properly. Forexample, effects of the tensor force on the Esym(ρ) are av-eraged out at the mean-field level. However, tensor forceinduced short-range correlations may alter significantly thekinetic and potential contributions to the total symmetry en-ergy and its slope [7]. While how the total symmetry energyis divided into kinetic and potential parts seems to have noobvious effect on describing properties of neutron stars asit is the total pressure and energy density that are neededin solving the Tolman-Oppenheimer-Volkoff (TOV) equa-tion, it is certainly important for simulating nuclear reac-tions using transport models describing the evolution ofquasi-nucleons in phase space under the influence of nu-clear mean-fields and collision integrals. The strong isospindependence of the tensor force may even lead to vanishingor negative Esym(ρ) at high densities, leading to the predic-tion of some interesting new phenomena in neutron stars[12]. Indeed, going beyond the mean-field level, various mi-croscopic many-body theories that incorporate correlationsto differing degrees have been used to predict the Esym(ρ).Unfortunately, the predictions still diverge broadly at supra-saturation densities.

The EOS of uniform and isospin-asymmetric nucleonicmatter described by Eq. (1) and the definition of its sym-metry energy have their ranges of validity too. For exam-ple, at low densities below the so-called Mott points, var-ious clusters start forming. One thus has to go beyond themean-field by considering correlations/fluctuations and in-medium properties of clusters in constructing the EOS ofstellar matter for astrophysical applications. Then the Eq.(1) is obviously no longer valid. Moreover, there seems tobe no need to introduce a symmetry energy of clusteredmatter for describing its EOS. In fact, for the clusteredmatter, because of the different binding energies of mir-ror nuclei, Coulomb interactions, different locations of pro-ton and neutron drip-lines in the atomic chart, the systemno longer possesses a proton–neutron exchange symmetry.

Moreover, different clusters in the medium have their ownlocal/internal isospin asymmetries and densities. Indeed, interms of the average isospin asymmetry δav of the wholesystem, the EOS of clustered matter has been found to haveodd terms in δav that are appreciable compared to the δ 2

avterm. Thus, it is conceptually ambiguous to define a sym-metry energy for clustered matter in the same sense as foruniform nucleonic matter.

Constraints on Nuclear Symmetry Energy at theSaturation Density

It is customary to characterize the density dependenceof nuclear symmetry energy near ρ0 by using the Esym(ρ0)and L(ρ0). In recent years, much progress has been madein constraining them using various observables from bothterrestrial laboratory experiments and astrophysical obser-vations. It is seen that the central values of the Esym(ρ0)and L(ρ0) scatter around Esym(ρ0) = 31.6 ± 2.66 MeVand L(ρ0) = 58.9 ± 16 MeV, respectively. As an exam-ple, shown in Figure 2 are values of the slope parameterL(ρ0) from 28 analyses in the literature. Observables usedin these analyses include the atomic masses, neutron-skinsof heavy nuclei, isospin diffusion in heavy-ion reactions,excitation energies of isobaric analog states (IAS), isoscal-ing of fragments from intermediate energy heavy-ion colli-sions, the electric dipole polarizability from analyzing thePygmy dipole resonance, the frequency of isovector giantdipole resonances, α and β decay energies, optical poten-tials from analyzing nucleon-nucleus scatterings, and sev-eral observables of neutron stars, etc. Interestingly, the re-sults in Figure 2 and from several other surveys indicate anempirical relation L(ρ0)≈ 2Esym(ρ0). Theoretically, the lat-ter approximation becomes exact when both the kinetic andpotential symmetry energies are proportional to (ρ/ρ0)

2/3.

Constraining the Density Dependence of NuclearSymmetry Energy Away from ρ0

While the community has made significant advancementin constraining the Esym(ρ0) and L(ρ0), determining thedensity dependence of nuclear symmetry away from thesaturation density is more challenging. First of all, modelpredictions are more diverse, especially at high densitieswhere the poorly known three-body force and possibly newdegrees of freedom become important. The density and mo-mentum dependence of the underlying isovector potentialdetermining the Esym(ρ) is also very model dependent. Toexperimentally probe the density dependence of nuclearsymmetry energy, one needs to study systematically staticproperties of nuclei or dynamical observables describingcollective motions of nuclei or nuclear reactions. For ex-ample, it is well known that in the nuclear mass/energyformula of finite nuclei, the isospin asymmetry appears

Page 12: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

feature article

10 Nuclear Physics News, Vol. 27, No. 4, 2017

Figure 2. Central values of L(ρ0) from 28 model analyses of terrestrial nuclear experiments and astrophysical observa-tions. Taken from Ref. [13].

in both the volume and surface terms. Rewriting the nu-clear contributions to the energy of finite nuclei of massnumber A as E(N,Z) = E0(A)+aasy(A)(N −Z)2/A whereE0(A) =−avA+asA2/3 is the symmetric part of the energyin terms of the volume and surface energy coefficients avand as, one can define the mass dependence of the sym-metry energy coefficient as aasy(A) ≡ 1/av

asy +A−1/3/asasy]

using the volume and surface symmetry energy coefficientsav

asy and asasy. The aasy(A) can be extracted from analyz-

ing atomic masses and/or excitation energies of the iso-baric analog states (IAS). By fitting the aasy(A) extractedfrom the IAS data with Skyrme-Hartree-Fock calculations,a constraining band on the Esym(ρ) between approximatelyρ0/3 and ρ0 was obtained by P. Danielewicz and J. Lee asshown in Figure 3.

Many reaction observables and phenomena rangingfrom cross-sections of sub-barrier fusion and fission atlow energies, energy and strength of various collectivemodes, isospin diffusion, isoscaling, ratios and differentialflows of protons and neutrons as well as mirror nuclei inheavy-ion reactions at intermediate energies, to hard pho-ton, pion, kaon, and η production in nuclear reactions up to10 GeV/nucleon have been proposed as promising probesof the Esym(ρ) (see, e.g., Refs. [2–8]). Most of these ob-servables probe directly the density and momentum depen-dence of the single-particle potential. For example, the sym-metry energy/potential plays the role of the restoring forcefor isovector collective modes of excited nuclei. Since theisovector potential is normally very small compared to theisoscalar potential, isospin-sensitive observables thus oftenuse relative or differential quantities/motions of neutronsand protons to enhance (reduce) effects of the isovector(isoscalar) potential. Depending on the conditions of thereactions, these observables may probe the Esym(ρ) over abroad density range.

Among many interesting experiments, it is worth em-phasizing that significant work has been done in constrain-ing the Esym(ρ) using heavy-ion reactions at intermediateenergies. For example, several transport model analyses ofthe experimental data on isospin diffusion between severalSn isotopes taken by M.B. Tsang et al. at NSCL/MSU haveconsistently extracted a constraining band on the Esym(ρ)between approximately ρ0/3 and ρ0 as shown with the greyband in Figure 3. While at supra-saturation densities thedata are very limited and various transport model calcula-

Figure 3. Constraints on the density dependence of Esym(ρ)from analyzing isospin diffusion, flow, and pion productionin heavy-ion reactions, isobaric analog states (IAS), prop-erties of double magic nuclei by B. A. Brown as well asbinding energies and neutron-skins of heavy nuclei by Z.Zhang and L. W. Chen. Taken from Refs. [14, 15].

Page 13: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

feature article

Vol. 27, No. 4, 2017, Nuclear Physics News 11

tions of reaction observables do not always converge. Forexample, as indicated with the black arrow, analyzing theπ−/π+ data from GSI taken by the FOPI collaboration us-ing a BUU-type (Boltzmann-Uehling-Uhlenbeck) transportmodel by Xiao et al. [15], the Esym(ρ) was found to de-crease with increasing density above about 2ρ0 as predictedby the Gogny-Hartree-Fock calculations. Later, the ASY-EOS Collaboration analyzed the relative flows of neutronsw.r.t. protons, tritons w.r.t. 3He and yield ratios of light iso-bars using two versions of the QMD-type (Quantum Molec-ular Dynamics) transport models [14]. They found, instead,a Esym(ρ) continuously growing with density. As shownclearly in Figure 3, there is a big disagreement regardingthe high-density behavior of the Esym(ρ). Certainly, ongo-ing and planned new experiments coupled with more the-oretical efforts using systematically tested reaction modelswill help improve the situation hopefully in the near future.

Concluding Remarks and OutlookThe density dependence of nuclear symmetry energy

Esym(ρ) is poorly known but very important for many in-teresting issues in both nuclear physics and astrophysics.Its accurate determination has broad impacts. Besides thechallenges in treating nuclear many-body problems, ourpoor knowledge about the isovector nuclear interaction isthe main origin of the uncertain Esym(ρ). At the mean-field level, the density and momentum dependence of boththe isoscalar and isovector single-nucleon potentials af-fects the Esym(ρ) and L(ρ). Going beyond the mean-fieldlevel, correlations and fluctuations, especially the short-range neutron–proton correlation due to the tensor forcein the isosinglet channel also affects the symmetry energyespecially at supra-saturation densities. Besides possiblephase transitions, the high-density symmetry energy hasbeen the most uncertain part of the EOS of neutron-richnucleonic matter.

Thanks to the hard work of many people in both nuclearphysics and astrophysics, much progress has been madein constraining the symmetry energy around and belowthe saturation density. In particular, rather consistent val-ues of Esym(ρ0) = 31.6±2.66 MeV and L(ρ0) = 58.9±16MeV have been obtained from many analyses using var-ious kinds of data and models. However, the uncertain-ties of some of these analyses need to be better quanti-fied while the Esym(ρ) at supra-saturation densities remainsrather uncertain.

Looking forward, advanced radioactive beam facilitieswill allow reactions with higher isospin-asymmetries, thusenlarging the observable effects induced by the isovec-tor nuclear interaction. Moreover, new experiments usingelectron-nucleus and (p,2pN) reactions at large momen-tum transfers investigating the isospin dependence of short-

range correlations in neutron-rich nuclei are being carriedout or planned to better understand effects of the tensorforce. Furthermore, new astrophysical observations, mostnoticeably the radii, frequencies of torsional oscillations,r-mode instability windows of neutron stars, neutrino fluxfrom supernovae explosions, cooling curves of protoneu-tron stars, gravitational waves from collisions involvingneutron stars, and so on, also provide exciting new opportu-nities for better constraining the Esym(ρ). Combining newinformation from both terrestrial nuclear experiments andastrophysics observations will certainly allow us to deter-mine much more precisely the symmetry energy of neutron-rich nucleonic matter in a broad density range.

References1. P. Danielewicz, R. Lacey, and W. G. Lynch, Science 298

(2002) 1592.2. A. W. Steiner, M. Prakash, J. M. Lattimer, et al., Phys. Rep.

411 (2005) 325.3. V. Baran, M. Colonna, V. Greco, and M. Di Toro, Phys. Rep.

410 (2005) 335.4. B. A. Li, L. W. Chen, and C. M. Ko, Phys. Rep. 464 (2008)

113.5. M. B. Tsang et al., Phys. Rev. C86 (2012) 015803.6. C. J. Horowitz, E. F. Brown, Y. Kim, et al., J. of Phys. G41

(2014) 093001.7. Topical Issue on Nuclear Symmetry Energy, Eds: B. A. Li, A.

Ramos, G. Verde, et al., Euro Phys. J. A50(2) (2014).8. M. Baldo and G. F. Burgio, Prog. Part. Nucl. Phys. 91 (2016)

203.9. C. Xu, B. A. Li, and L. W. Chen, Phys. Rev. C82 (2010)

054607.10. O. Hen et al., Science 346 (2014) 614.11. X. H. Li, B. J. Cai, L. W. Chen, et al., Phys. Lett. B721 (2013)

101.12. M. Kutschera et al., Acta Physica Polonica B37 (2006) 277.13. B. A. Li and X. Han, Phys. Lett. B727 (2013) 276.14. P. Russotto et al. (ASY-EOS Collaboration), Phys. Rev. C94

(2016) 034608.15. Z. G. Xiao, B. A. Li, L. W. Chen, et al., Phys. Rev. Lett. 102

(2009) 062502.

BAO-AN LI

Page 14: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

feature article

12 Nuclear Physics News, Vol. 27, No. 4, 2017

IntroductionNuclear physics applications in medicine and energy are

well known and widely reported. For example, the recent report “Nuclear Physics for Medicine,” published by the European Science Foundation [1] or “Energy for the Fu-ture: The Nuclear Option,” written by scientists at the Eu-ropean Physical Society (EPS) [2] can be mentioned. Less well known are the many important nuclear and related techniques to study objects of cultural heritage. There has been enormous progress in this field in recent years and our current contribution provides some snippets of the compre-hensive topical paper “Nuclear Physics for Cultural Heri-tage” published by the EPS recently [3], which aims for a popular and accessible account showing the broad nuclear physics applications in cultural heritage investigation and preservation. Nuclear Physics contributes to archaeometry mainly by non-invasive investigation of cultural heritage objects with ion and neutron beams.

Developments of Ion Beam Analytical methods (IBA) were related to progress in low-energy accelerators, in de-tectors for particle, X-ray, and g ray measurements, and in systems for processing experimental data [4, 5]. Ion beams of several MeV, produced by small accelerators, penetrate into matter, interact with the atoms of the sample and pro-duce, among other phenomena, X-rays and g rays, which provide information about the investigated artefacts. Small accelerators can generate a wide range of ion beams, with flexible energy range (and thus adjustable probed depth) and diameter of the beam (from millimeter to micrometer size). Hence, such instruments can provide us with tailored tools for the study of the diverse objects of Cultural Heri-

tage [6] that should remain intact after being exposed to analytical investigation. Therefore, non-destructive meth-ods are of crucial importance for investigations.

To this day, Neutron Activation Analysis (NAA) has been mostly used at research reactors, which provide high-intensity neutron fields. In combination with high-resolu-tion HPGe detectors complex g-spectra from irradiated ma-terial can be disentangled and the concentration of up to 45 major and trace elements can be determined in one sample. Although NAA usually requires placing a cultural-heritage object (or a representative sample of it) for neutron irradia-tion into the reactor, a chemical pre-treatment of the mate-rial is not necessary. This procedure therefore preserves the original element composition of the object.

The Nuclear Physics Division of the EPS offers publi-cation of the leading scientists in Europe, especially those results derived from ion beams, neutron beams, dating methods, and many other nuclear analytical methods [3]. Likewise, the publication offers exciting stories about many historical artefacts, paintings, papyrus, precious stones, an-cient jewelry, and the provenance of numerous artefacts and ancient manufacturing technology.

How Do Ion and Neutron Beams Investigate Matter?Ion Beam Analytical Techniques

Although ion beam analysis was developed later than other methods—simply because suitable accelerators only became available in the second half of the 20th century, it is now the most versatile technique for investigating ob-jects of cultural significance. A multitude of different ion

Ion and Neutron Beams Discover New Facts from HistoryAnnA MAcková1,2, Jan Kučera1, Jan KameníK1, Vladimir HaVráneK1, and Karel Kranda11 Nuclear Physics Institute of the Czech Academy of Sciences, v. v. i., Husinec-Řež, Czech Republic 2 Department of Physics, Faculty of Science, J.E. Purkinje University, Ústí nad Labem, Czech Republic

Archaeometry involves analytical and dating methods for object characterization. Nuclear phys-ics contributes significantly to the dating methods (e.g., radiocarbon dating, thermoluminescence dating, optically stimulated luminescence dating) and to the analytical methods making possible to determine practically all the elements of the periodic table and enabling to reconstruct the spatial distribution of elements present in the sample.

Page 15: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

feature article

Vol. 27, No. 4, 2017, Nuclear Physics News 13

beam techniques is now available: NRA (Nuclear Reaction Analysis), PIXE (Proton Induced X-Ray Emission), PIGE (Proton Induced g-ray Emission), RBS (Rutherford Back-Scattering), and ERDA (Elastic Recoil Detection Analysis) see Figure 1.

Standard equipment for IBA methods comprises an elec-trostatic accelerator (Figure 2), generating ions such as pro-tons, deuterons, He, and heavier ions, with energies from 0.5–50 MeV. Such a facility also includes associated ion beam-lines and vacuum target chambers where the samples

are irradiated. The products of ion interactions with sample atoms are recorded with semiconductor detectors coupled to electronic devices for processing detector signals and data acquisition. PIXE and RBS are the most used methods for the comprehensive element analysis. Depending on the sample type and measuring apparatus, the concentration of elements with Z > 5 can be determined with PIXE down to about 0.1–1 μg.g–1. This method is not used for element depth profiling, because of its low depth resolution. The ma-jor advantage of PIXE’s use of ions is a reduction in the background activity when compared to those methods where electrons are used as the probe (electron microprobe induced X-ray emission). In the case of RBS, the depth profiling of elements utilizes the defined charged particle energy losses in the investigated material with the depth resolution better than 10 nm. For heavy elements, in a light substrate, the de-tection limits are about 0.01 atomic percent (at. %).

In ion microprobe analysis, the samples are irradiated with an ion beam focused to a quadratic spot of about 1 × 1 μm. Standard IBA techniques (PIXE, RBS) are used for the characterization of the irradiated part of the sample. Fig-ure 3 displays an arrangement for ion microprobe analysis. By scanning the beam within a defined window across the surface of the sample a 3D distribution of elements can, in principle, be determined with a nm depth resolution and a lateral resolution limited only by the size of the beam spot. For this purpose, the signals detected are assigned to the x,y coordinates of the beam spot [7].

Figure 1. The basic principles of ion beam analytical methods. The probe ions with mass M are penetrating the sample and elastically back-scattered ions or elastically recoiled particles are recorded (upper part). Proton beams are inducing X–ray or γ-ray emission based on inelastic scattering with atoms or nuclear reaction, respectively (bottom part).

Figure 2. Tandetron accelerator with ion beam-lines, vac-uum chambers, and detectors used for the various nuclear analytical methods in Center of Accelerators and Nuclear Analytical Methods (CANAM), Nuclear Physics Institute of the Czech Academy of Sciences, the Czech Republic.

Figure 3. Microbeam arrangement at Tandetron accelera-tor (CANAM, Nuclear Physics Institute of the Czech Acad-emy of Sciences, the Czech Republic), the vacuum chamber for placing specimen on the right and magnetic quadrupole triplet lenses for focusing the beam to micrometer size on the left.

Page 16: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

feature article

14 Nuclear Physics News, Vol. 27, No. 4, 2017

In order to measure the distribution of elements along a line, or map the elemental distribution over an area, the sample must be scanned with the focused beam spot and the detector signal recorded as a function of the displacement of the beam from its normal position. When a beam of ions scans an area of a specimen, the emitted radiation carries information in three degrees of freedom—the two spatial dimensions (x,y coordinates) and the energy [7]. Scanning ion microprobe (SIMP) and scanning proton microprobe are very useful techniques for in situ element or isotope distribution analysis.

In practice, materials or artefacts often cannot be placed in a vacuum chamber because of their large size or the pres-ence of volatile components. Such samples can be analyzed with an external ion beam. Such a beam consists of ions that pass through a thin window from the vacuum to the air environment. In a standard arrangement, the beam spot at the target is a millimeter or less in diameter if the beam is shaped by slits, but it can reach 10 or 30 μm if the beam is focused with suitable magnetic optics [8].

Neutron Activation analysisNeutron activation analysis is a multi-elemental analyti-

cal technique used for qualitative and quantitative analysis of major, minor, and trace elements. Samples weighing, typically in the range from sub-mg to g, are irradiated with neutrons and the newly formed radioisotopes are created, mostly via the (n,γ) nuclear reaction with thermal neutrons (neutron radiative capture). The radioactive decay of newly formed radionuclides is often accompanied by the emission of characteristic γ-rays. The irradiation is usually carried out at a nuclear reactor but other neutron sources (radioiso-topic or accelerator based) can also be used. The neutrons used for irradiation are categorized as cold, thermal, epith-ermal (resonance) or fast, according to their energy. In gen-eral, the lower the neutron energy, the higher the probability of the neutron radioactive captures. Detection limits are pri-marily determined by neutron capture cross-sections; that is, the probability of the (n,γ) reaction, neutron flux, abun-dance of the target isotope and the measured characteristics of the emitted radiation. NAA can detect up to 74 elements depending on the experimental procedure, with minimum detection limits ranging from 10–7 to 10–12 g g–1, depend-ing on the element and matrix composition. The NAA tech-nique requires a small sample to be taken from the object analyzed (e.g., by drilling in an inconspicuous place) but the size of the sample is usually so small that damage to the object is minimized. Thanks to its high potential for accu-racy and well defined theoretical background (all sources of uncertainty can be experimentally evaluated or modelled).

NAA with relative standardization has recently been recog-nized as a primary method of measurement (e.g., a method with the highest metrological properties [9]).

What Can We Discover?

Pigment and Body Composition of Chinese Ming Pottery Found in Angkor

The purpose of the investigation was to determine the possible origin of Chinese pottery sherds, presumably dat-ing to the Ming dynasty found in excavated material from an ancient pool at the Royal palace grounds of Angkor Thom. As the former imperial city was abandoned shortly after its sack by the Thai armed expedition in 1431 the ar-tefacts found on the grounds probably had been imported by the Royal court while still at Angkor Thom. It was our intention to separately analyze the composition of the glaze and the painted sections containing cobalt (Figures 4a and b). Furthermore, we attempted to find the possible origin of the kilns in China where the sherds found were actually manufactured. Hence, we compared the characteristic trace element content in the sherds body determined by macro PIXE and the composition of the cobalt pigment inclusions determined by µ-PIXE with reported measurements of ele-mental composition of ancient Chinese porcelain produced at various kiln locations in China [10]. The shards, cuts, and corresponding µ-PIXE maps are shown in Figures 4c and d.

The sherds were sliced to thin sections and examined with a microscope coupled to a camera to identify the ele-ments of the cobalt-pigment decorations and the glaze. The samples were placed in aluminium holders and irradiated with a proton beam that was focused to a 1 micrometer spot with an Oxford triplet quadrupoles (Figure 3). Both the macro- and micro-PIXE analyses were done on the same samples. The proton beam energy of a Tandetron accel-erator was varied between 2 and 3 MeV according to the atomic mass of the elements desired for investigation in a particular experimental session.

Up to 20 elements were typically determined during each macro PIXE measurement with sufficient detection limits to determine trace content of Cu, Zr, Rb, and Y, nec-essary for sherds source appointment. From the µ-PIXE analysis the maps of individual elements were constructed from their emission spectra showing a space-resolved con-centration of each particular element. The examples of Ca and Co element distributions can be seen in Figure 4c and d. The advantage of the measurements reported here is their superior spatial resolution, which enabled us to target the individual pigment spots and reduce the partial volume ef-fects of wider beam measurements. Our sample analysis

Page 17: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

feature article

Vol. 27, No. 4, 2017, Nuclear Physics News 15

found Ca values similar to those reported for Chinese pot-tery of the Ming dynasty.

Microbeam measurement of the sherds cross-section clearly distinguished the glaze on the shards, as calcium content is much higher in the glaze (see Ca 2D elemen-tal maps in Figure 4d). From the comprehensive elemental analysis of about 20 elements in the glaze, body, and cobalt pigment, it appears that the pigment was most likely im-ported from Persia and that the shards analyzed were manu-factured in kilns at two distinct locations in China [11].

Was He Murdered or Was He Not? Determination of Mercury in the Remains of Tycho Brahe

World-renowned Renaissance astronomer Tycho Brahe (Figure 5) died on 24 October 1601, after 11 days of sud-den illness. Several conspiracy theories, namely mercury poisoning, had been aired shortly after his death. To test the murder hypothesis, Brahe’s grave in Prague was re-opened in 2010 and samples of his bones, hair, teeth, and the textiles were collected and analyzed. For NAA, hairs with identifiable roots were cut into ~5 mm long sections.

Figure 4. Cobalt blue sherds found in the excavated sediments from the pool of the Royal palace in Angkor Thom (a, b). PIXE analysis using an incident proton ion beam of 2 MeV using a microbeam provided 2D element maps of Co (c) in the blue pigment and Ca content (d) of the glaze (bottom) on the sherd cross-section (top).

(a) (b)

(c) (d)

Page 18: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

feature article

16 Nuclear Physics News, Vol. 27, No. 4, 2017

The sectioned hair samples from 20–25 individual hairs weighing 200–300 µg were sealed in pre-cleaned high-pu-rity quartz ampoules and irradiated in the LVR-15 nuclear reactor in Řež (operated by Research Centre Řež, Ltd.) at a thermal neutron fluence rate of 3 × 1013 cm–2 s–1 for 20 h. The 203Hg radionuclide formed was chemically separated after 2–3 weeks of decay using an NAA procedure [12], based on Hg extraction with 0.01 mol L–1 Ni diethyl di-thiocarbamate (Ni(DDC)2). The extract was measured with high-resolution gamma-spectrometry.

Unsectioned hair samples were also analyzed by μ-PIXE, using a Tandetron 4130 MC accelerator with a 2.6 MeV proton beam focused to a diameter of 1.5 µm. Mul-tiple scans were performed over 500 µm sections of hair at a 0.1 nA beam current for 1–3 h (Figure 6a and b to follow the concentration of trace and matrix elements with spe-cial focus on Hg concentration). The concentrations and the spatial distributions of the other elements are also impor-tant, as these may provide some information on a possible hair surface contamination, hair aging process and reveal

the health and professional status of a particular person. The element map of Fe in Figure 6a shows external con-tamination of the hair specimen analyzed, demonstrating that μ-PIXE could distinguish between the elements present on the hair surface and those homogeneously distributed in the hair matrix, like S in Figure 6b.

Figure 7 shows an excellent agreement between the NAA and μ-PIXE results for one hair sample from Tycho Brahe. These values were found to be comparable to the median and ranges of Hg contents in the contemporary non-exposed population. Hair provides a lasting record of exposure to trace metals over the last few months of life. The hair samples analyzed in this study relate to the Hg in-take over approximately the last 2 months prior to the death of Tycho Brahe, assuming the most frequently cited hair growth rate of 10 mm per month [13].

The highest Hg values found in Brahe´s hair are slightly above the median of ”normal“ values but are still within the normal range. The Hg concentration decline along the hair length indicates that Brahe was not exposed to any exces-sive Hg doses shortly before his death (Figure 7). Analysis

Figure 5. Tombstone from the grave of Tycho Brahe (1546–1601) situated at the Church of Our Lady before Týn, Prague, the Czech Republic.

Figure 6. PIXE 2D elemental map of middle part of hair for different elements Fe (a) and S (b).

(a)

(b)

Page 19: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

feature article

Vol. 27, No. 4, 2017, Nuclear Physics News 17

of Brahe’s bones revealed no long-term exposure to Hg (no chronic poisoning). Thus the analyses carried out falsify the hypothesis that the famous astronomer was poisoned by Hg and his presumed murder is nothing but a fiction.

ConclusionsThe application of atomic and nuclear techniques to

studying archaeological objects provides a historian or archaeologist with hard data that can facilitate our under-standing of the past. This knowledge is necessary for test-ing the authenticity and provenance of ancient artefacts. In some cases, the data of spatially resolved element analysis provide useful information for decision to be made about the restoring approach to be taken. These objectives are presumably already shared by the majority of people work-ing in the field of archaeometry. In general, once it becomes accepted that from more detailed studies of the past we may learn more about the present, it seems likely that the desire to better understand our cultural heritage and the need to protect it will grow.

References 1. F. Azaiez, A. Bracco, J. Dobeš, et al. (eds.), Nuclear Physics

for Medicine, Nuclear Physics European Collaboration Com-mittee (NuPECC) (2014), http://www.nupecc.org/npmed/npmed2014_hires.pdf

2. H. Freiesleben, R. C. Johnson, O. Scholten et al., Energy for the Future: the Nuclear Option, Position Paper of the Euro-pean Physical Society (2007), http://c.ymcdn.com/sites/www.eps.org/resource/resmgr/policy/eps_pp_option_2007.pdf

3. A. Mackova, D. MacGregor, F. Azaiez, et al. (eds.), Nuclear Physics for Cultural Heritage, Topical paper of the Nuclear Physics Board of the EPS (2016), http://www.edp-open.org/images/stories/books/fulldl/Nuclear-physics-for-cultural- heritage.pdf

4. J. R. Tesmer and M. Nastasi, Handbook of Modern Ion Beam Materials Analysis (Material Research Society, Pittsburgh, PA, 1995).

5. A. Macková and A. Pratt, Ion/Neutral Probe Techniques, Handbook of Spectroscopy: Second, Enlarged Edition (Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 2014).

6. J.-C. Dran et al., Nucl. Instr. and Meth. in Phys. Res. B 219–220 (2004) 7.

7. L. E. Murr, Electron and Ion Microscopy and Microanaly-sis: Principles and Applications (Marcel Dekker, New York, 1991).

8. L. Giuntini, Anal. Bioanal. Chem. 401 (2011) 785. 9. R. R. Greenberg, P. Bode, E. A. de Nadai Fernandes, Spectro-

chim. Acta Part B 66 (2011) 193.10. P. L. Leung and H. Luo, X-Ray Spectrom. 29 (2000) 34.11. K. Kranda, V. Havránek, V. Peřina, et al.. On the Composition

of Cobalt Pigment of Chinese Ming Pottery Found In Angkor, TECHNART 2011—Berlin, 26–29 April 2011.

12. J. Kučera and L. Soukal, J. Radioanal. Nucl Chem. 168 (1993) 185.

13. K. L. Rasmussen, J. Kučera, L. Skytte, et al., Archaeometry 55 (2013) 1187.

Figure 7. Time course of Hg contents in one sample of Ty-cho Brahe’s hair.

AnnA MAcková

Jan Kučera

Jan KameníK

Vladimír HaVráneK

Karel Kranda

Page 20: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

facilities and methods

18 Nuclear Physics News, Vol. 27, No. 4, 2017

IntroductionLast year some two hundred pres-

ent and former collaborators came to Leuven to celebrate the fiftieth an-niversary of the Instituut voor Kern-en Stralingsfysica (IKS; Institute for Nuclear and Radiation Physics). The institute originated in the slipstream of the separation of the Catholic Uni-versity of Leuven into two parts: the Flemish KU Leuven, remaining in the city of Leuven and the French Uni-versité Catholique de Louvain, situ-ated in the new town of Louvain-la-Neuve. The IKS started in 1967 with two professors, two Ph.D. students, and three technicians. Its physics pro-gram was influenced by the work of Professor Erwin Bodenstedt at the In-stitut für Strahlen-und Kernphysik of the Universität Bonn. It concentrated on the measurement of magnetic mo-ments of excited nuclei using radioac-tive ion implantation and hyperfine techniques such as perturbed angular correlation, Mössbauer spectroscopy, and nuclear orientation. Although in the beginning solid-state physics is-sues related to implantation were treated as secondary but necessary in-put for the nuclear physics questions, it developed soon as an independent, complementary research line. In 1970, an off-line separator for long lived radioactive isotopes was installed in Leuven (LIS—the Leuven Isotope Separator) while in 1974 the Leuven Isotope Separator On Line (LISOL) was installed at the CYCLONE cyclo-tron in Louvain-la-Neuve. The scien-tific focus of LISOL was on moment measurements, detailed β-decay stud-ies, and decay spectroscopy of nuclei far from stability. In 1986 the univer-sities of Louvain-la-Neuve, Leuven,

and Brussels joined efforts to build the first post-accelerated ISOL facil-ity, starting reaction studies of astro-physical interest using radioactive ion beams. On the other hand, besides the standard hyperfine techniques for solid-state physics, Rutherford back-scattering and channeling experiments started at the Van de Graaff accel-erator in Louvain-la-Neuve but were soon continued at the 1.7 MV Tandem Pelletron at imec (the Interuniversity Micro-Electronics Center, Leuven) and finally in 1994, in-house, in a new laboratory, the Ion and Molecular Beam Laboratory (IMBL) (Figure 1).

Next to the local activities (Leu-ven and Louvain-la-Neuve) a strong program was also developed at inter-national facilities such as ISOLDE-CERN, GSI-Darmstadt, GANIL-Caen, PSI-Villigen, ESRF-Grenoble,

whereby the IKS researchers were not only frequent users but also signifi-cantly contributed to long-term strat-egies and projects at some of these large-scale facilities within interna-tional collaborations.

In a very natural way, two general lines of research have emerged from the growth of IKS, namely nuclear structure and reaction physics, and nuclear solid-state physics. While the collaboration between the different research groups has remained strong, the different pace of those fields has also lead to many independent devel-opments.

Nuclear Structure and Reaction Physics

The fundamental understanding of nature is the driving force behind most of the research in nuclear physics. At

The Institute for Nuclear and Radiation Physics at the University of Leuven

Figure 1. Layout of the Ion Molecular Beam Laboratory.

Page 21: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

facilities and methods

Vol. 27, No. 4, 2017, Nuclear Physics News 19

IKS, we challenge our understanding of the weak interaction or of the strong force in exotic nuclear systems. In both aspects, modern experimental re-quirements are high, in order to work with short-lived, exotic nuclei as well as developing state-of-the-art systems to manipulate and study the nucleus.

Selective Production of Radioisotopes for Decay Spectroscopy

The study of radioactive ion beams is heavily linked to their availability. This is why IKS has a long history of research into their production. For example, LISOL used proton- and heavy-ion-induced reactions on thin targets in a gas catcher in combination with resonant laser ionization to study the decay of isotopes from elements out of reach of many other ISOL fa-cilities, such as refractory and metallic ions. The study of ground-state prop-erties with in-gas laser spectroscopy was also made possible for 57Cu or 97Ag, both isotopes that allowed prob-ing nuclear structure in the vicinity of doubly closed shell nuclei, namely 56Ni and 100Sn. A new milestone was recently reached by performing the resonant laser ionization in the super-sonic gas jet exiting the gas catcher, in-stead of inside the gas volume, hereby reducing the broadening suffered by the atomic transitions of interest with-out any loss in efficiency [1]. This new avenue of research is now under full study at the new in-house Heavy Element Laser IOnization Spectros-copy (HELIOS) laboratory (Figure 2), in preparation for the study of very heavy and super heavy elements at the Super Separator Spectrometer (S3) at GANIL-SPIRAL2.

The IKS research program also cov-ers the region of Z = 82 and N = 104, midway between N = 82–126, where shape coexistence is found at low en-ergy. Developments of laser ionization schemes were made together with the

Resonant Ionization Laser Ion Source (RILIS) collaboration at ISOLDE for radioactive elements such as po-lonium and astatine. These develop-ments are key to an important survey of the ground-state properties from 79Au to 85At. In parallel, an extensive study of β-delayed fission in that re-gion revealed fission fragment dis-tributions that were at odds with the intuitive understanding of the process and have sparked a lot of theoretical studies. Finally, IKS is one of the driv-ing forces behind the ISOLDE Decay Station (IDS) program, a new modu-lar experiment at ISOLDE that offers many opportunities for the study of decay spectroscopy.

High-Resolution Study of Ground-State Properties

In collinear laser spectroscopy, a traveling beam is overlapped with laser radiation. Thanks to the accel-eration process, the velocity distribu-tion is forward-focused and the ion-source broadening disappears. IKS has participated for many years in laser spectroscopy, developing origi-

nal techniques at the LISOL separator before bringing its knowledge to the COLLAPS collaboration at ISOLDE [2]. IKS took a special interest in the island of inversion near N = 20 as well as in the vicinity of magic num-bers, like Z = 28 and Z = 50. In order to push those studies to more exotic systems, a higher level of sensitivity was necessary; this was achieved first by the introduction of bunched-beam laser spectroscopy, and then finally by combining the collinear laser spec-troscopy with resonant ionization at the CRIS experiment [3].

Not all isotopes are, however, di-rectly accessible by laser spectros-copy. For the study of the island of inversion around N = 20, a research program making use of β-NMR and β-NQR has been developed at the LISE spectrometer at GANIL.

Fundamental Interactions in Subatomic Particles

The angular correlation between the β-particle and the polarized nu-clear spin or the neutrino are being studied with 35Ar and the β-delayed

Figure 2. The laser setup in the HELIOS laboratory. (Source: Marilyn De Smet-aboutmary.be)

Page 22: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

facilities and methods

20 Nuclear Physics News, Vol. 27, No. 4, 2017

proton decay of 32Ar, respectively, thereby probing scalar or tensor type weak interaction forms. Earlier stud-ies of this type have been performed with the NICOLE and WITCH setups at ISOLDE [4, 5]. Other approaches are also being investigated using the LPC Trap setup at GANIL.

This program is complemented with the search for the neutron electric dipole moment, a property that would highlight physics beyond the Standard Model. This search is carried out with the nEDM experiment, originally de-signed at the Institut Laue-Langevin (ILL) in Grenoble (France) [6] and now carried out at the Paul Scherrer Institute (PSI) in Villingen (Switzer-land). After a successful first study that has reached the highest sensitiv-ity on this observable, the nEDM ex-periment is currently undergoing an upgrade to push further the sensitivity limit. The IKS contribution lies in the coordination of one of the two analy-sis teams and the precise monitoring and stabilization of the magnetic field within the setup with magnetometry techniques developed at IKS.

Post-Accelerated Radioactive Ion Beams

IKS also has a long tradition of studying nuclear reactions with post-accelerated beams. In the wake of the successful study of post-accelerated 13N at the CRC, which started in 1986, a large nuclear astrophysics and struc-ture program was carried out at this facility for 20 years. Meanwhile, the research program has diversified to many facilities and many techniques, like in the MiniBall Collaboration, where Coulomb excitation experi-ments are carried at safe energies in the region of Z = 28 and N = 40–50, as well in the region of the neutron-deficient lead isotopes [7]. By com-bining the MiniBall germanium detec-tor array with the T-REX silicon array,

transfer reactions have also been per-formed to study the island of inversion near N = 20 and in the Z = 28 region [8]. The new HIE-ISOLDE post-ac-celerator, with increased beam energy, will allow to further this program by reaching higher excited levels in Coulomb excitation and higher cross sections in transfer reactions. The re-action study program is completed by extensive new developments into new technologies, such as the active targets (ACTAR, SpecMAT) and the ISOL Solenoid Spectrometer (ISS).

Nuclear Solid-State PhysicsAs pointed out in the introduc-

tion, it was very soon realized that hyperfine interactions could not only be used to study nuclear properties, but in a reverse approach enable one to investigate the electronic, struc-tural, and magnetic properties of the environment of a (known) nucleus. Based on this strategy, a strong solid-state physics research program was set up, mainly based on Mössbauer spectroscopy (MS), perturbed angu-lar correlation (PAC) spectroscopy, and low-temperature nuclear orienta-tion (LTNO). At the heart of these ex-periments was the LIS off-line isotope separator, which delivered a variety of long-lived radioactive “spy” ions with energies up to 100 keV. A disad-vantage of using ion implantation for radioactive doping—also in nuclear physics studies—are the irradiation-induced damage to the host and the often unknown lattice site of the probe atom. These challenges triggered a broadening of the solid-state research from merely hyperfine interactions to ion–solid interactions [9], and in-dicated the start of a broad ion beam research program, including ion im-plantation, ion irradiation, ion beam synthesis, and ion beam analysis. Fi-nally, it became clear that full under-standing of the hyperfine or ion beam

experiments often requires a profound theoretical analysis. From the early 1990s on, a variety of ab initio, Monte Carlo, and molecular dynamics codes entered the lab, and ever since these computational approaches [10] have become indispensable.

During the past 50 years, the mate-rials under investigation have signifi-cantly changed. Often driven by major challenges in (micro-electronics) tech-nology—but always aiming at under-standing the fundamental interactions and processes underlying the sys-tems—our research has focused on thin films, interfaces, surfaces, and nano-structures. Indeed, due to their very local interaction, both hyperfine and ion techniques are ideally suited for in-vestigating small systems. The general goal is to understand the intimate link between the structure of a material and its functional properties, in particular when reducing the size below a critical length. Throughout the years, a number of trends have emerged.

Trend 1: The Need for Complementary, Non-nuclear Characterization

Unlike many of the early studies, it is no longer possible to capture (and understand) the full picture based on hyperfine or ion interactions alone. Little by little, complementary tech-niques for synthesizing and analyz-ing low-dimensional samples were added, ranging from molecular beam epitaxy (MBE) to scanning tunnel-ing microscopy (STM) and X-ray diffraction (XRD). In 1994, the ma-jority of the equipment was brought together and coupled in vacuo in the IMBL (Figures 1 and 3), which cur-rently comprises two MBEs, two ion implanters and a Pelletron accelerator, along with a wide range of surface and thin film characterization techniques. During the past decades, the IMBL has played a crucial role in studies of

Page 23: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

facilities and methods

Vol. 27, No. 4, 2017, Nuclear Physics News 21

(magnetic) multilayers [11], surface diffusion [12], silicides [13], and dop-ing of materials [14]. In particular, the capability to deposit (sub)monolayers of enriched isotopes (e.g., for MS or LTNO) allows probing the properties as a function of depth—from the sur-face down to the interface. Recently, a strategic decision was taken to group state-of-the-art infrastructure in the Leuven NanoCentre, where we have installed atom probe tomography (2016) and focused ion beam (2017) on vibration-controlled floor, allowing for 3-D compositional characteriza-tion with sub-atomic resolution. A ma-jor fraction of the analysis is done in close collaboration with the Materials Characterization group in imec.

Trend 2: From “Stand-Alone” toward “On-line,” “In Situ,” or “Real Time” Experiments

Studies on ultra-small samples or ultra-thin films (which require keep-ing the sample in vacuum throughout the experiment), at very low tempera-tures (including implantation in fro-zen noble gases [15]), using extremely

low implantation energies (down to 5 eV, resulting in “implantation” on a surface) or short-lived isotopes [16], or ion beam analysis during a thin film reaction [17]—all need on-line characterization. To this end, experi-ments allowing in situ sample growth, modification, and characterization have been set up at LIS, the IMBL, ISOLDE, and iThemba LABS. Al-though the stringent boundary condi-tions drastically enhance the level of complexity, the unique capabilities are most often extremely rewarding.

Trend 3: The Need for Large-Scale Facilities

Whether it concerns short-lived or exotic radioactive ions (for MS or emission channeling), polarized neutrons (for probing structure and magnetism in thin films), or high-bril-liance (focused) photons (for nuclear resonant scattering, the time-domain equivalent of MS), large-scale facili-ties such as ISOLDE, ILL or HZB, and ESRF or APS, have been playing an important role in our studies [18]. Just as an example, the capability to focus

14.4 keV photons (i.e., the 57Fe Möss-bauer transition) of a synchrotron al-lows one to probe magnetic properties as a function of depth (using a wedge sample) or as a function of pressure (using a diamond anvil cell). More-over, capturing the inelastic scattering allows to investigate phonons in nano-structured systems.

Hence, it is clear that nuclear solid-state research has moved a long way during the past 50 years, from pure hyperfine studies in the early days, to very broad characterization platforms nowadays.

Future PerspectivesThe integration of the different

research avenues and the interaction between the different themes has been key to the strength of IKS in the last 50 years. It remains a driving force of this institute and new projects are emerging from recent developments.

At ISOLDE, a new laser polar-ization beam-line has been commis-sioned to serve a variety of research themes: study of oriented nuclei for fundamental decay studies with 31Ar, biomolecular studies with metal ions, and surface interactions probed with radioactive nuclei deposited by soft landing with the ASPIC setup.

The effort invested into radioactive ion beam production and purification will be valorized in the new CERN MEDICIS facility (MEDical Isotopes Collected from ISolde), offering regu-lar radioisotope delivery for novel nu-clear medicine. A collaboration with local research hospitals and a larger European network will promote the use of the ISOL method for nuclear medicine toward developing new targeted therapy treatments and PET-aided hadron therapy [19].

IKS is investing in some of the new, large-scale, European projects in nuclear physics: HIE-ISOLDE and SPIRAL2, both quite advanced in

Figure 3. Doctoral students working the Ion Molecular Beam Laboratory. (Source: Layla Alerts, www.laylaaerts.be)

Page 24: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

facilities and methods

22 Nuclear Physics News, Vol. 27, No. 4, 2017

their construction, and in the ISOL@MYRRHA project at the SCK•CEN-Mol. It is a member of the Belgium EURISOL Consortium, supporting the EURISOL Distributed Facility and the EURISOL project.

IKS is now a full-grown research institute hosting nine full-time pro-fessors and three 10% professors; 21 postdocs, senior scientists, and en-gineers; and 30 Ph.D. students. The research portfolio contains nuclear structure physics focused on exotic nuclei, and nuclear solid-state phys-ics focused on ion–solid interactions. The goals of our research are to under-stand the strong and weak interaction in the nuclear medium and to unravel the link between the structure of a material and its functional properties. Moreover, there is a strong awareness of the impact our research can have on neighboring fi elds such as atomic physics and nuclear astrophysics, and on possible applications such as the development of novel medical radio-isotopes.

AcknowledgmentsThe research from our institute

has been made possible thanks to the support from KU Leuven, as well as regional, national, and European sup-port from the following agencies: Belspo, the European Commission, FWO, Hercules, IIKW, IWT.

References 1. R. Ferrer et al., Nat. Comm. 8 (2017)

14520. 2. L. Vermeeren et al., Phys. Rev. Lett. 68

(1992) 1679. 3. R.P. de Groote et al., Phys. Rev. Lett.

115 (2015) 132501. 4. G. Soti et al., Phys. Rev. C 90 (2014)

035502. 5. P. Finlay et al., Eur. Phys. J. A 52

(2016) 206. 6. M. Pendlebury et al., Phys. Rev. D 92

(2015) 092003. 7. N. Bree et al., Phys. Rev. Lett. 112

(2014) 162701. 8. J. Diriken et al., Phys. Lett. B 736

(2014) 533–538. 9. E. Verbiest et al., Nucl. Instr. Meth.

182 (1981) 515.10. S. Cottenier and H. Haas, Phys. Rev. B

62 (2000) 461.11. J. Meersschaut et al., Phys. Rev. Lett.

75 (1995) 1638.12. K. Paredis et al., Appl. Phys. Lett. 92

(2008) 043111.13. M.F. Wu et al., Appl. Phys. Lett. 67

(1995) 3886.14. L.M.C. Pereira et al., Appl. Phys. Lett.

98 (2011) 201905.15. M. Vanderheyden et al., Phys. Rev. B

36 (1987) 38.16. U. Wahl et al., Phys. Rev. Lett. 118

(2017) 095501.17. J. Demeulemeester et al., Appl. Phys.

Lett. 93 (2008) 261912.18. S. Couet et al., Adv. Funct. Mat. 24

(2014) 71.19. L. Buehler, T.E. Cocolios, J. Prior, T.

Stora, CERN Courier 56 (2016) 28.

THOMAS ELIAS COCOLIOS

KU Leuven, Physics & Astronomy, Institute for Nuclear & Radiation

Physics, Leuven, Belgium

MARK HUYSE

KU Leuven, Physics & Astronomy, Institute for Nuclear & Radiation

Physics, Leuven, Belgium

ANDRÉ VANTOMME

KU Leuven, Physics & Astronomy, Institute for Nuclear & Radiation

Physics, Leuven, Belgium

View current and forthcoming book titles at:

Page 25: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

facilities and methods

Vol. 27, No. 4, 2017, Nuclear Physics News 23

The setup for experiments with electron bremsstrahlung is one of the beam-lines at the Center for High-Power Radiation Sources of Helm-holtz-Zentrum Dresden-Rossendorf, Germany. The heart of the center is a superconducting electron linear accel-erator of high brilliance and low emit-tance (ELBE). Generated in a therm-ionic gun, the electron beam passes the subsequent main accelerator modules. The floorplan in Figure 1 shows the various beam-lines for the production of secondary radiation around the ac-celerator. In addition to the beam-line for bremsstrahlung (gELBE), there are facilities for the production of positrons (pELBE) with systems for monoenergetic positron spectroscopy, for the production of fast neutrons with a time-of-flight system (nELBE), two free-electron lasers (FELBE), and a THz source (TELBE). The electron beam is directly used, for example, for detector tests with a high time resolu-tion. Also, the ELBE building houses high-power lasers for experiments on laser-particle acceleration, also in combination with the electron beam.

The bremsstrahlung facility [1] uses the electron beam behind the first accelerator module, where a maximum electron energy of about 18 MeV is available in connection with a maximum average current of about 0.7 mA, and the accelerator is oper-ated in continuous-wave (cw) mode with a repetition rate of 13 MHz. Part of the beam-line and the experimen-tal cave are depicted in Figure 2. To produce bremsstrahlung, the electron beam hits a niobium foil of selectable thickness between 2 and 12 mm. Be-hind the radiator foil, a 2.60 m long collimator of pure aluminum, installed in the concrete wall between the accel-erator hall and the experimental cave, forms a g beam from the bremsstrah-lung cone. In the experimental cave, the g rays travel in an evacuated beam-line before being dumped in a poly-ethylene block, surrounded by a cad-mium foil and a layer of lead bricks. The target to be studied is mounted in the beam tube. g rays scattered from the target are measured with four high-purity (HPGe) detectors of 100% relative efficiency. Two of them are

positioned at angles of 90° and two at 127° relative to the beam direction. All detectors are surrounded by es-cape-suppression shields made of bis-muth germanate (BGO) scintillation detectors. It should be emphasized that the materials of the components of the setup, such as the collimator, the evacuated beam tube, the alumi-num detector stands and the photon beam dump, were chosen such that the scattering of g radiation into the detec-tors and the production of neutrons via (g,n) reactions are largely sup-pressed. The beam characteristics of the ELBE accelerator in combination with the efficient detector setup in a low-background environment provide unique conditions for nuclear-physics experiments with bremsstrahlung and for experiments on positron-annihila-tion lifetimes [2]. A photograph of the setup is shown in Figure 3.

Photoexcitation of NucleiThe excitation and deexcitation of

atomic nuclei by electromagnetic ra-diation are fundamental processes in reactions of this many-body quantum

Nuclear-Physics Experiments at the Bremsstrahlung Facility γELBE

Figure 1. Floorplan of the ELBE Center for High-Power Radiation Sources.

electronsg

free-electron lasers

THz facility

neutronlab

accelerator hall

accelerator electronics

optical labs

positronlab

neutrontime-of-flight

lase

r 500TW laser Draco

PW DPSSL Penelope

laser ion acceleration

laser electron acceleration

PW exp. area

x-ray lab

rays

Page 26: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

facilities and methods

24 Nuclear Physics News, Vol. 27, No. 4, 2017

system. At high excitation energy and high level density, statistical models are applied to describe reaction rates, which use g-ray strength functions to describe the average transition proba-bilities in a certain range of excitation energy. The experimental determina-tion and the theoretical understand-ing of the properties of g-ray strength functions has attracted increasing interest because of their importance for the accurate description of photo-nuclear reactions and the inverse radi-ative-capture reactions, which play a central role in the synthesis of the ele-ments in various stellar environments.

Above the neutron-separation en-ergy, the dipole strength function and the related photoabsorption cross-sec-tion of nuclei in the ground state are dominated by the electric dipole (E1) giant dipole resonance (GDR), observ-

able in (g,n) experiments. The shape of the GDR has been phenomenologi-cally described by a standard Lorentz function or an extended expression in-cluding terms taking into account nu-clear temperature [3]. Double humps or a widening of the GDR caused by quadrupole and triaxial deformation are reproduced with combinations of two or three Lorentz functions [4]. In addition, the magnetic dipole (M1) ab-sorption has been taken into account by two Lorentz functions, which de-scribe the scissors mode appearing in deformed nuclei around 3 MeV and the spin-flip mode appearing around 8 MeV [3, 5].

In the excitation-energy range from about 6 MeV to the neutron threshold, enhanced E1 strength on top of the low-energy tail of the GDR has been observed in various mass regions.

This E1 strength is often referred to as a pygmy dipole resonance (PDR). An overview about studies of the PDR is given in Ref. [6]. Most of the experi-ments with bremsstrahlung at gELBE have focused on the investigation of dipole strength in the energy region of the PDR and the spin-flip resonance up to the neutron threshold.

Photon-Scattering Experiments at γELBE

Photon scattering from nuclei, also called nuclear resonance fluorescence (NRF), is a suitable tool to study the photoabsorption cross-section and the related dipole strength function below the neutron threshold. NRF ex-periments at gELBE enable the study of photoabsorption cross-sections in a wide energy range, even up to the highest neutron-separation energies that can reach values up to about 15 MeV for light, neutron-deficient nu-clei. However, two complications, of-ten neglected in NRF experiments at lower energy in the past, become very important for the excitation of nuclei up to high excitation energy. First, the level density can be very high and a considerable number of transitions is not resolved but forms a quasicon-tinuum in the measured spectrum and second, a nuclear state can deexcite to low-lying excited states (inelastic scattering) in addition to the ground state (elastic scattering). This means that (a) the intensity in the quasicon-tinuum has to be included in the analy-sis and (b) the branching ratios of the ground-state transitions have to be es-timated.

To determine the intensity in the nuclear quasicontinuum, the spectrum of g rays scattered from the target in atomic processes is simulated by using the code GEANT4 [7] and subtracted from the response- and efficiency-corrected experimental spectrum. The contributions of unresolved strength

1 m

Be window

dipole

dipole

dipole

radiator

steerer

quadrupoles

quadrupole

electron-beam dump

quartz windowbeam

hardenercollimator

target

PbPE

door

Pb

photon-beamdump

Pb

HPGe detector

experimentalcave

acceleratorhall

Figure 2. The bremsstrahlung facility γELBE and the experimental cave.

Page 27: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

facilities and methods

Vol. 27, No. 4, 2017, Nuclear Physics News 25

2 3 4 5 6 7 8 9 10Eγ (MeV)

100

101

102

103

104

105

106

Cou

nts

experimental spectrum

atomic background

139La(γ,γ’) Eekin = 11.5 MeV

2 3 4 5 6 7 8 9 10Eγ (MeV)

100

101

102

103

104

105

106

Cou

nts

208Pb(γ,γ’) Eekin = 17 MeV

experimental spectrum

atomic background

to the spectra are demonstrated for the nuclides 139La [8] and 208Pb [9] in Figure 4. It is obvious that there is a considerable amount of intensity in the nuclear quasicontinuum above the atomic background in the spectrum of 139La, which has a high level den-sity, whereas the atomic background coincides with the continuum in the spectrum of 208Pb, which has a com-paratively small level density, and thus reduced intensity in the nuclear quasicontinuum.

In the analysis of the spectrum ob-tained after subtraction of the atomic background, simulations of statistical g-ray cascades using the code gDEX [10, 11] are performed to estimate in-tensities of branching transitions from high-lying to low-lying excited states. The branching ratios of the ground-state transitions obtained in this way are applied to deduce the photoab-sorption cross-section from the mea-sured scattering cross-sections.

The various steps of the analysis are shown in Figure 5 for the exam-ple of 86Kr [12]. The photoabsorption cross-section obtained from the analy-sis just described connects to the (g,n) cross-section at the neutron threshold, which proves the applied procedures and underlying model assumptions. Note the enhanced strength in the en-

ergy range from about 6 to 10 MeV, which is considered as the PDR [12].

Results and ProspectsThe NRF experiments at gELBE

have improved our knowledge of dipole-strength functions below the neutron-separation energy. Enhanced strength in the PDR region has been studied in several N = 50 isotones and compared with predictions of the quasiparticle-phonon approximation and the quasiparticle-phonon model [12]. A systematic study of the dipole strength in the PDR region of xenon isotopes revealed that the strength increases with the neutron number, whereas the nuclear deformation has a minor influence [11]. An important issue in all these investigations was the inclusion of strength in the quasi-continuum of states at high excitation energy in the analyses. For this and for the estimate of branching ratios of the ground-state transitions, special statis-tical techniques were developed and applied at HZDR [10, 11], which have meanwhile been adopted by other groups. The photoabsorption cross-sections, determined in this way con-tinuously up to the neutron threshold, can be combined with (g,n) cross-sec-tions and provide experimental input strength functions over a wide energy

Figure 3. Detector setup at γELBE. At the left side, the exit of the collimator is seen. The beam travels in the evacuated black plastic tube. The target is mounted in the tube and is observed by four HPGe detectors surrounded by BGO escape-suppression shields. The γ beam is stopped in the beam dump at the right side.

Figure 4. Response-corrected experimental spectra (red) measured in the 139La(γ,γ9) (left panel) and 208Pb(γ,γ9) (right panel) experiments at γELBE com-pared with simulated atomic backgrounds (blue), multiplied with efficiency and measuring time. Data from Refs. [8,9].

Page 28: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

facilities and methods

26 Nuclear Physics News, Vol. 27, No. 4, 2017

range for the calculation of reaction rates in statistical codes [13, 14]. In pa rticular, neutron-capture rates ob-tained in this way are used to describe processes of the nucleosynthesis [15].

Currently, the gELBE facility is also used by several external groups for experiments using photon scattering. The data gained from the experiments with broad-band bremsstrahlung are often combined with those from ex-periments at the quasimonoenergetic and polarized g-ray source HIgS [16], which allow a distinction between E1 and M1 transitions.

References 1. R. Schwengner et al., Nucl. Instr.

Meth. A 555 (2005) 211.

2. M. Butterling, W. Anwand, T. E. Cowan, et al., Nucl. Instr. Meth. B 269 (2011) 2623.

3. R. Capote et al., Nucl. Data Sheets 110 (2009) 3107.

4. A. R. Junghans, G. Rusev, R. Schwengner, A. Wagner, et al., Phys. Lett. B 670 (2008) 200.

5. K. Heyde, P. von Neumann-Cosel, and A. Richter, Rev. Mod. Phys. 82 (2010) 2365.

6. D. Savran, T. Aumann, and A. Zilges, Prog. Part. Nucl. Phys. 70 (2013) 210.

7. S. Agostinelli et al., Nucl. Instr. Meth. A 506 (2003) 250.

8. A. Makinaga et al., Phys. Rev. C 82 (2010) 024314.

9. R. Schwengner et al., Phys. Rev. C 81 (2010) 054315.

10. R. Massarczyk et al., Phys. Rev. C 86 (2012) 014319.

11. R. Massarczyk et al., Phys. Rev. Lett. 112 (2014) 072501.

12. R. Schwengner et al., Phys. Rev. C 87 (2013) 024306.

13. M. Beard, S. Frauendorf, B. Kämpfer, et al., Phys. Rev. C 85 (2012) 065808.

14. N. Tsoneva, S. Goriely, H. Lenske, and R. Schwengner, Phys. Rev. C 91 (2015) 044318.

15. R. Raut et al., Phys. Rev. Lett. 111 (2013) 112501.

16. H. R. Weller et al., Prog. Part. Nucl. Phys. 62 (2009) 257.

RONALD SCHWENGNER

Institute of Radiation Physics,Helmholtz-Zentrum

Dresden-Rossendorf

ANDREAS WAGNER

Institute of Radiation Physics,Helmholtz-Zentrum

Dresden-Rossendorf

4 5 6 7 8 9 10 11 12Ex (MeV)

0

5

10

15

20

25

σγ (

mb)

86Kr

(γ,γ’)corr

(γ,n)

Sn(γ,γ’)peaks

(γ,γ’)

TLO

Figure 5. Cross-section data for 86Kr in different steps of the analysis. Black tri-angles: scattering cross-sections in energy bins of 0.2 MeV deduced from inten-sities of resolved paks. Blue squares: scattering cross-sections σγγ including the intensity in the quasicontinuum. Red circles: photoabsorption cross-sections σγ corrected for the branching ratios b0 of the ground-state transitions (σγ = σγγ/b0) [12]. Green diamonds: (γ,n) cross-sections [15].

Send information on your future events to [email protected]

Page 29: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

meeting reports

Vol. 27, No. 4, 2017, Nuclear Physics News 27

Istros 2017, the third edition of the international conference on Iso-spin, STructure, Reactions and energy Of Symmetry, was held in Častá-Papiernička, Slovakia on 14–19 May 2017. This biennial conference is or-ganized by the Institute of Physics of the Slovak Academy of Sciences in Bratislava. It was the ancient name of the Danube river, Istros, which served as an inspiration for the name of the conference.

The conference aims at providing a platform for a meeting of international and Slovak scientists active in the field of nuclear physics, specifically deal-ing with experimental and theoretical aspects of physics of exotic nuclei and states of nuclear matter. The organiz-ers keep the number of participants low, which allows long talks to be given and also to reserve plenty of time for informal discussions.

Over 50 scientists from 17 coun-tries from five continents participated in the conference (Figure 1). The sci-entific program included more than 40 oral presentations. The confer-ence started with a session devoted to the investigations of the nuclear equation of state in ultra-relativistic nucleus–nucleus collisions. Recent results from the ALICE collaboration (LHC) were presented, in particular on observed strangeness enhance-ment in p+Pb reactions, as well as on the search for chiral magnetic effects. Other topics covered by presentations from ALICE collaboration were pro-duction of light nuclei and anti-nuclei and particle femtoscopy, specifically baryon correlations and first results for kaon correlations. The presented results from the STAR collaboration highlighted the search for the QCD

critical point by the beam energy scan program at RHIC, looking for chiral magnetic effects as well as observa-tion of the Lambda polarization and the measurement of antimatter inter-action. In a further presentation during the workshop, beam energy scaling of charged particle multiplicity was sug-gested as a possible signature of phase transition in ultra-relativistic nucleus–nucleus collisions.

Another widely discussed topic, re-lated to the equation of state, was the density dependence of symmetry en-ergy and its influence on astrophysical processes and cosmology. In particu-lar, possible negative symmetry en-ergy at high densities was discussed, along with EoS-gravity degeneracy and resulting possibilities for modi-fied gravity and new bosonic particles representing fifth force.

Modern theoretical methods for determination of symmetry energy in finite nuclei and of equation of state of neutron matter were also discussed.

Several presentations focused on production and properties of heavy

and superheavy nuclei. Recent results were presented of production of new flerovium isotopes at Dubna. Decay spectroscopy of transfermium nuclei was discussed in several talks, along with the results from studies of spon-taneous fission. Production of heavy and superheavy nuclei via multi-nu-cleon transfer was a topic of several theoretical and experimental presenta-tions. Also the influence of the nuclear equation of state on fusion hindrance, preventing the production of heavy nuclei, was discussed.

Experiments with radioactive beams at the new generation of nu-clear physics facilities were discussed in several presentations. Modern de-tectors such as active targets and the SAMURAI facility were described and results on the study of exotic nuclei close to the dripline were pre-sented.

Investigations on production mech-anism of intermediate mass fragments in nucleus–nucleus collisions and on influence of isospin degree of free-dom, performed using the CHIMERA

The International Conference on Isospin, Structure, Reactions, and Energy of Symmetry: Istros 2017

Figure 1. Group photo of the conference attendees.

Page 30: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

meeting reports

28 Nuclear Physics News, Vol. 27, No. 4, 2017

array, were presented. An interesting presentation was given also on statis-tical production of hypernuclei.

Statistical production of light nu-clei such as carbon or oxygen was also a topic of presentation, focusing on possible medical applications.

Several sections addressed prob-lems related to nuclear structure phys-ics. It was shown that the concept of deformation-driving orbitals, where its manifestation should be most pro-nounced, is not supported by existing data. The belief that nuclear moments of inertia depend on pairing corre-lations is not supported by existing data. The status of understanding of the structure of odd-Au isotopes was presented.

Results on single nucleon transfer reactions on 198,200Hg isotopes yield-ing important information on the sin-gle-particle nature of 199Hg isotope, which provides the most stringent limit on an atomic electric dipole mo-ment to date.

Coulomb excitation technique for studies of phenomena such as shape coexistence and evolution of collectiv-ity was presented in great detail. It was shown that Coulex experiments bring rich and precise nuclear structure data that can be interpreted in terms of de-formation parameters but at the mo-ment only very favorable cases stud-ied with radioactive-ion beam attain quality of stable beam experiments.

Nuclear triaxiality as a next challenge for the Coulomb excitation technique was discussed.

One session was dedicated to the ISOLDE facility. General overview that involved the recently commis-sioned HIE-ISOLDE upgrade (post accelerator of radioacitive-ion beams) was given. The laser spin polariza-tion, β-NMR spectroscopy, and laser spectroscopy of negative ions, which are techniques used at ISOLDE, were discussed.

Recent results on the nuclear struc-ture of seaborgium, rutherfordium, and nobelium isotopes were presented. Underground nuclear astrophysics was presented, which is pursued by the LUNA collaboration in the Gran Sasso laboratory. The 400 kV cur-rent LUNA accelerator and the unique low-background conditions of the underground LNGS laboratory have been and still are the perfect blend for the study of most of the proton-cap-ture reactions involved in the stellar H burning. On the other hand, a beam of higher energy is required to extend these studies to reactions between heavier isotopes, as those operating during more advanced phases of stel-lar evolution, namely the He and the C burnings. The LUNA MV project has been developed to overcome such a limit with the new 3.5 MV single-ended accelerator to be installed in Gran Sasso in summer 2018.

The recently commissioned 2 MV Tandetron, which is operational at the Institute of Physics, Slovak Academy of Sciences in town of Piešťany (Slo-vakia), was presented. The scientifi c program of the new laboratory is fo-cused on nuclear structure studies and on stellar nucleosynthesis reactions.

The venue offered many oppor-tunities for animated scientifi c dis-cussions, both indoors and outdoors. Social program included a wine tast-ing at the winery school in the nearby city of Modra. The conference dinner presented to the participants Slovak national cuisine and wines. Excellent weather allowed participants to enjoy walks and bicycle rides in the sur-rounding outdoors of the Little Car-pathian hills in Bratislava’s hinterland. Also, the sport facilities at the venue such as a swimming pool and squash were available for the participants.

The conference was supported by the Ministry of Education, Science, Research and Sport of the Slovak Re-public, by the Slovak Physical Soci-ety, and by the Slovak Research and Development Agency under Contract No. APVV-15- 0225.

MARTIN VESELSKY AND MARTIN VENHART

Slovak Academy of Sciences

:: Site maintenance by Gabriele-Elisabeth Körner. Design by Dan Protopopescu (2009)

The Nuclear Physics European Collaboration Committee is an Expert Committee of the European Science Foundation

www.nupecc.org

Page 31: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

meeting reports

Vol. 27, No. 4, 2017, Nuclear Physics News 29

The INFN—Laboratori Nazionali del Sud (LNS) and the Dipartimento di Fisica e Astronomia of the Uni-versity of Catania (DFA) were the hosts of the “8th Nuclear Physics in Astrophysics” international confer-ence (NPA8) that was held from 18–23 June 2017 in Catania, Italy. This conference could not have been orga-nized without the support of several sponsors from the academic arena to industrial partners. These are the Is-tituto Nazionale di Fisica Nucleare, the Dipartimento di Fisica e Astrono-mia of the University of Catania, the European Physical Society, Mesytec, CAEN, IOP, and EPJ.

Catania represented an exception-ally suited venue. From a scientific point of view, Catania hosts one of the oldest universities in Europe and one of the four national laboratories of INFN. From a historic, artistic,

and natural point of view, downtown Catania and the nearby Mount Etna are registered in the UNESCO World Heritage List.

The conference, initiated by the Nuclear Physics division of the Eu-ropean Physical Society, was the suc-cessor of earlier events held in Eilat, Israel, in 2001 (but moved to Debre-cen, Hungary) and, with a 2-year fre-quency, in Debrecen (Hungary) (two times), in Frascati (Italy, originally planned to be hosted by INFN—Labo-ratori Nazionali del Gran Sasso), Eilat (Israel), and in York (UK).

The conference was made up of 16 plenary oral sessions and 1 poster session. Each oral session was opened by approximately two invited talks. Invited speakers of the plenary ses-sions were selected based on their age, talent, impact, and with a right bal-ance in gender by a scientific program

committee on the basis of recommen-dations of an international advisory committee.

In the same spirit as the earlier editions, NPA8 was the showcase for the most recent developments in the field of nuclear astrophysics cover-ing a wide range of topics from fun-damental aspects to instrumentation and astrophysical applications. Room was given not only to the traditional aspects of experimental nuclear astro-physics, such as direct measurements above and underground and indirect approaches, but also to emerging fields such as the measurement of fusion re-actions in laser-induced plasmas and of photodissociation reactions. Also significant room has been given to novel experimental techniques that might have important impact on future nuclear astrophysics experiments and on astrophysical modeling and obser-

NPA8: The 8th Nuclear Physics in Astrophysics International Conference

 

In the same spirit as the earlier editions, NPA8 was the showcase for the most recent

developments in the field of nuclear astrophysics covering a wide range of topics from

fundamental aspects to instrumentation and astrophysical applications. Room was given not

only to the traditional aspects of experimental nuclear astrophysics, such as direct

measurements above and underground and indirect approaches, but also to emerging fields

such as the measurement of fusion reactions in laser-induced plasmas and of

photodissociation reactions. Also significant room has been given to novel experimental

techniques that might have important impact on future nuclear astrophysics experiments and

on astrophysical modeling and observations, which constitute the necessary motivations and

background of the proposed measurements.

<LE>Figure 1. Group picture.</LE>

The conference counted about 150 participants from 24 countries (Figure 1) with 94

oral contributions and 24 poster presentations with a broad spectrum of topics in the field of

nuclear astrophysics, including big bang nucleosynthesis, quiescent stellar burning in the

main sequence and in advanced evolutionary stages, novae and supernovae explosions, X-

ray bursts, p-, rp-, s-, and r-processes, from both the experimental, theoretical, and

Figure 1. Group picture from the conference.

Page 32: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

meeting reports

30 Nuclear Physics News, Vol. 27, No. 4, 2017

vations, which constitute the neces-sary motivations and background of the proposed measurements.

The conference counted about 150 participants from 24 countries (Figure 1) with 94 oral contributions and 24 poster presentations with a broad spec-trum of topics in the field of nuclear astrophysics. The event was attended by a large number of researchers at the start of their scientific career together with well-established senior scientists. Such a diversity in experience, nation-ality, and research expertise made NPA8 an ideal platform for cross-fertilization between the disciplines, stimulating new ideas and scientific networks. The participation of young researchers and of scientists from less favored countries was possible thanks to the EPS conference grants and the support from the local organizing committee, who made available cheap or free accommodation for many par-ticipants.

On 19 June the Conference chair-men, C. Spitaleri and M. Lattuada, inaugurated the meeting. The director of the Laboratori Nazionali del Sud of INFN, G. Cuttone, and the director of the INFN Section of Catania wel-comed all the participants.

The highlights of the scientific part of the conference came from various invited presentations given each ses-sion throughout the week by the most talented physicists predominantly from within the European countries. The most recent developments, results, and future perspectives in the different research areas were presented and dis-cussed creating a lively atmosphere, intriguing researchers outside the field of expertise as well. After the invited talks, sessions were open to experts in the respective fields, providing also the opportunity for graduate students and young postdocs to present their work. In particular, we underscore the participation of C. Bertulani as EPS

invited speaker, who presented the recent activity on clustering in nuclei and its connection with the problem of electron screening.

During NPA8 a special event was organized, to celebrate the scientific achievements of the conference chair-man, C. Spitaleri, on the occasion of his retirement (Figure 2). The ses-sion was opened by the conference co-chair, M. Lattuada, and hosted nine invited speakers including long-time collaborators of C. Spitaleri and world-renown experts in the field of nuclear astrophysics, discussing the scientific background and impact of his scientific career.

The poster session on Tuesday, 20 June was also very lively and trig-gered many useful discussions among the participants. During the poster session, members of the international scientific and program committee evaluated the posters. In particular, the poster by G. F. Ciani about the direct measurement of the 13C(α,n)16O reac-tion at LUNA was selected.

Finally, the host of the forthcoming “9th Nuclear Physics in Astrophys-ics International Conference” was

announced by N. Colonna, member of the EPS Nuclear Physics Division Board, on 21 June. The 9th edition of this conference will be held in Frank-furt, Germany, and will be jointly organized by Goethe University, the Max-Plack-Institute for Nuclear Phys-ics, the Technical University of Darm-stadt, and the GSI.

The Proceedings of NPA8 will be published in Open Access on EPJ Web of Conferences. All contributions have been subjected to peer review prior to publication.

ORCIDM. La Cognata

http://orcid.org/0000-0002-1819-4814

C. Spitaleri and M. lattuada

Department of Physics and Astronomy, University of Catania,

Italy, and INFN—Laboratori Nazionali del Sud, Catania, Italy

M. la Cognata INFN—Laboratori Nazionali del Sud,

Catania, Italy

 

<Footer>Nuclear Physics News, Vol. 27, No. 4, 2017</Footer>

<Footer> Vol. 27, No. 4, 2017, Nuclear Physics News</Footer>

<LRH> meeting reports</LRH>

<RRH> meeting reports </RRH>

<CT>NPA8: The 8th Nuclear Physics in Astrophysics International Conference</CT>

<LE>Figure 2. Prof. C. Spitaleri, fifth from the right, on the celebration of his retirement. <AQ>Please confirm mention

of each figure in the article or update as needed.</AQ></LE>

The INFN—Laboratori Nazionali del Sud (LNS) and the Dipartimento di Fisica e

Astronomia of the University of Catania (DFA) were the hosts of the “8th Nuclear Physics

in Astrophysics” international conference (NPA8) that was held from 18–23 June 2017 in

Catania, Italy. This conference could not have been organized without the support of several

sponsors from the academic arena to industrial partners. These are the Istituto Nazionale di

Fisica Nucleare, the Dipartimento di Fisica e Astronomia of the University of Catania, the

European Physical Society, Mesytec, CAEN, IOP, and EPJ.

Figure 2. Prof. C. Spitaleri, fifth from the right, on the celebration of his retire-ment.

Page 33: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

meeting reports

Vol. 27, No. 4, 2017, Nuclear Physics News 31

The 17th edition of the international conference on Strangeness in Quark Matter (SQM 2017) was held from 10–15 July 2017 at Utrecht University in the Netherlands (http://sqm2017.nl). The SQM series focuses on new experimental and theoretical develop-ments on the role of strangeness and heavy-flavor production in heavy-ion collisions, and in astrophysical phe-nomena related to strangeness. This year’s SQM event attracted more than 210 participants from 25 countries (Figure 1), female researchers mak-ing up 20% of the attendees. A two-day-long graduate school on the role of strangeness in heavy ion collisions with 40 young participants preceded the conference.

The scientific program consisted of 53 invited plenary talks, 70 contrib-

uted parallel talks, and a poster ses-sion. Three discussion sessions pro-vided scope for the necessary debates on crucial observables to characterize strongly interacting matter at extreme conditions of high baryon density and high temperature and to define future possible directions. One of the discus-sions centered on hadronic resonance production and their vital interactions in the partonic and hadronic phase, which provide evidence for an ex-tended hadronic lifetime even in small collision systems and might affect other QGP observables. Moreover, future astrophysical consequences for SQM following the recent detection of gravitational waves were outlined: gravitational waves from relativis-tic neutron star collisions can serve as cosmic messengers for the phase

structure and equation-of-state of dense and strange matter, quite similar to the environment created in relativ-istic heavy-ion collisions.

Representatives from all major collaborations at CERN’s Large Had-ron Collider and Super Proton Syn-chrotron, Brookhaven’s Relativistic Heavy Ion Collider (RHIC), and the Heavy Ion Synchrotron SIS at the GSI Helmholtz Centre in Germany made special efforts to release new data at this conference. Thanks to the excel-lent performance of these accelerator facilities, a wealth of new data on the production of strangeness and heavy quarks in nuclear collisions has be-come available.

Among the highlights presented at the conference, the ALICE collabora-tion reported new results on strange

Strangeness in Quark Matter

Figure 1. More than 210 participants attended the 2017 meeting of the Strangeness in Quark Matter conference in Utrecht. [Image Credit: Pieter van Dorp van Vliet, Utrecht University].

Page 34: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

meeting reports

32 Nuclear Physics News, Vol. 27, No. 4, 2017

and multi-strange hyperon production in heavy-ion collisions with a colli-sion energy of 5.02 TeV per nucleon-nucleon pair and the first measurement of charm baryons (Lc and Xc) in pro-ton–proton and proton-lead collisions at the LHC. Furthermore, ALICE performed the most precise measure-ment of the hypertriton lifetime, an exotic nucleus composed of a proton, a neutron, and a lambda particle. The CMS collaboration reported progress in understanding the different energy losses for charm and beauty quarks in the hot QCD medium, while the STAR experiment at RHIC gave an update on global lambda polarization, which reveals that the curl of the fluid cre-ated at RHIC is much higher than that in any fluid ever observed. Enhanced strangeness production in small sys-tems, as reported by the HADES, NA61/SHINE, and ALICE collabora-tions, has also reignited the discussion surrounding strangeness production as a signature of the quark-gluon plasma.

Experimentally, the field faces high prospects for future measurements at the Facility for Antiproton and Ion Research in Darmstadt, NICA at JINR Dubna, and at CERN (namely detec-tor upgrades at the LHC during long shutdown 2 and the AFTER program).

On the theory side, new develop-ments and vigorous research efforts are taking place toward a full under-standing of strangeness production and open heavy-flavor dynamics in heavy-ion collisions. Global polariza-tion in heavy-ion collisions is also a current topic of interest since it allows the study of the vorticity of the me-dium and the initial magnetic field.

Four young scientist prizes, spon-sored by the European Physical Jour-nal A, were awarded to the best par-allel talk and poster presenters: Heidi Schuldes (Goethe University Frank-furt, Germany), Christian Bierlich (Lund University, Sweden), Yingru Xu (Duke University, USA), and Vojtech Pacik (Niels Bohr Institute, Denmark).

The next edition of the SQM con-ference will take place in Bari, Italy, in June 2019.

ORCIDAndré Mischke

http://orcid.org/0000-0003-0078-4522

André Mischke Utrecht University,

The Netherlands

NotePublished with license by Taylor & Francis© André MischkeThis is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecom mons.org/licenses/by-nc-nd/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The moral rights of the named author(s) have been as-serted.

READ LEARN DISCUSS PARTICIPATE

Page 35: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

news and views

Vol. 27, No. 4, 2017, Nuclear Physics News 33

IntroductionGiving an overview of the origins

and development in Cuba of Nuclear Physics and related technologies, 37 years after the creation of the Cuban Nuclear Program (PNC) is an arduous task, but it is pertinent to briefly ex-plain how the Cuban nuclear pathway was born and developed; the context when the complex infrastructure that the PNC demanded was erected, from the pillars.

In 1976, the construction of a nu-clear power plant in Juraguá was part of an intergovernmental agreement signed with the USSR, which by its significance it was considered “The Endeavor of the Century.”

To integrate all efforts into a co-herent national strategy, with well-defined objectives and priorities, and to create a solid infrastructure for the development of the nuclear energy, in January 1980, the Cuban Atomic Energy Commission (CEAC), and the Executive Secretariat for Nuclear Affairs (SEAN) were constituted [1]. The first was aimed at enforcing the policy that had been approved to co-ordinate and control the efforts of the national entities involved in nuclear activity and the SEAN was in charge of implementing the approved policy and developing the scientific, techni-cal, regulatory infrastructure, interna-tional ties, and the human capital.

The Fifteen Decisive Years (1980–1994)

In those years [2], the two centers for systems of Radiological Protec-tion and Nuclear Safety: the Center for Radiation Protection and Hygiene (CPHR) and the Nuclear Safety Cen-ter (CSN) were created; two for pro-moting basic research applied and the dissemination of isotopic techniques

and products: the Center of Applied Studies for Nuclear Development (CEADEN) and the Center of Isotopes (CENTIS); a small nuclear university: the Higher Institute of Nuclear Sci-ences and Technologies (ISCTN); and four institutions for the higher mid-level: three Specialized Pre-university Institutes in Exact Sciences (IPECE) and one nuclear polytechnic; and two as support for information and au-tomation: the Nuclear Energy Infor-mation Center (CIEN), and the Main Calculation Center of the SEAN. An-other major project was the Nuclear Research Center (CIN), which was implemented from the projection and construction until 1992, when like the CEN-Juraguá, it was interrupted.

A crucial aspect of that period should be mentioned briefly: The im-pact of selection and training of hu-man resources for the PNC. As a result of an initiative by the SEAN and the Resolution of the Ministry of Educa-tion (MINED), in 1980, the three men-tioned IPECE were established for the study of science and engineering in higher education, which were an especially valuable source of excel-lent graduates for the Nuclear sphere,

reaching 28% of total nuclear profile students.

As to higher education, up to 1980 only 48 professionals had graduated from nuclear specialties. However, up until mid-1992, the total number of graduates in the USSR, Eastern European countries, and Cuba, in around 50 specialties, amounted to approximately 1,100. In 1987—start-ing from the Faculty of Science and Nuclear Technologies (FCTN) of the University of La Habana, founded in 1981—was created the ISCTN. This well-equipped university pre-pares highly qualified professionals in Nuclear Physics, Radiochemistry, Nuclear Engineering (the specialty was called Nuclear Power) and Physi-cal Engineering. In 2003, ISCTN was renamed the Higher Institute of Tech-nologies and Applied Sciences (IN-STEC) and incorporated the specialty of Meteorology. Table 1 shows the re-sults to date.

As a result of the international geopolitics and the subsequent world crisis, in the early 1990s, the main nu-clear investments were suspended and the PNC was slowed down. In 1994, the Ministry of Science, Technology

On the Development of Nuclear Physics in Cuba

FCTN 1981–87

ISCTN 1988/2013 (/2 of them 1988–1992)

INTEC 2003–2016

Total graduates

Energy & nuclear tech. engineering

1781 203 /2 101 163 544

Nuclear physics 32 181 /2 76 156 369Nuclear physics engineering

0 45 /2 32 0 45

Radiochemistry 0 121 /2 29 125 246Total 210 550 /2 238 358 1204

Table 1. Total number of graduates in nuclear specialties broken down according to academic years, specialties, and institutes of higher education.

1The specialty was called Nuclear Energy; 2total graduates between 1988–1992.

Page 36: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

news and views

34 Nuclear Physics News, Vol. 27, No. 4, 2017

and Environment (CITMA) was cre-ated by merging the already existing Academy of Sciences (ACC) with SEAN. It also founded its Agency for Nuclear Energy and Advanced Tech-nologies (AENTA).

Nuclear Technology Applications in Cuba

The scientific and innovation ac-tivity in the field of Nuclear Physics can be grouped into three fundamental areas: applied, theoretical, and experi-mental research.

At present, there are about 160 in-stitutions and sectors under different ministries that apply nuclear technolo-gies and radioactive sources. Table 2 shows the AENTA’s centers by sectors and application areas [3].

The main applications are related to the analytic and nucleonic meth-ods used in applied Nuclear Physics: neutron activation analysis (NAA), gamma spectrometry (GS), X-ray flu-orescence (XRF), neutron reflection and moderation, beta backscattering, gamma transmission and absorption, and the track etching technique. For the mathematical simulation of the

interaction with radiation, the tools of Theoretical Nuclear Physics are used. Equipment based on interaction with the substance of different types of ion-izing radiations (neutrons, gamma ra-diation, and beta) have been designed and built for industrial applications in: the nickel industry, sugar industry, and the detection of weaknesses in welded joints in the steel and mechanical industry. Within the National Geo-logical Prospection Program, was the prospecting of uranium and thorium, both in deposits as well as in associa-tion with other minerals. Another of these applications based on the effects of ionizing radiations, in this case on biological minerals, is the creation of improved varieties of several eco-nomic crops.

The applications in Public Health have been notable and diverse; sig-nificant achievements have been made in the production and use of radio-pharmaceuticals in nuclear medicine in general as well as in open source therapies and the application of closed source radiation therapy for safe and efficient treatments against cancer.

In order to guarantee the metrol-ogy, the Radionuclide Metrology Lab-oratory (CENTIS-DMR) at CENTIS and the Secondary Dosimetric Cali-bration Laboratory (LSCD) at CPHR was created. Another service of un-doubted scientific and social value is the study of the biological effects of ionizing radiations. The use of estima-tion methods of radiological dosage in accidental situations allowed ob-taining positive results with the chil-dren and other people affected by the Chernobyl accident [4]. Among 1990 and 2012, almost 25 thousand persons from Ukraine, Belarus, and Russia were treated with internationally rec-ognized results.

The Development of Theoretical and Experimental Nuclear Physics

Scientific activity in the field of Nu-clear Physics from the organizational approach of the PNC can be divided into two stages (Table 3). In the first, between 1980–1995, the objectives of scientific programs were defined; the conditions and infrastructures were created and the head institutions and the leading groups were consolidated.

Sector Institution Area of applicationHealth CENTIS Production of radiopharmaceuticals and pharmacokinetic studies

CEADEN Radiosterilization (tissues, products for medicinal use)Agriculture and industry CEADEN Irradiation technologies (radiometagenesis of plants)

INSTEC Gamma and neutron profiling (optimization of industrial processes)Environment CEADEN X-ray fluorescence system (analytic determination of environmental samples)

INSTEC Neutron activation analysis and other related analytic techniques (analytic determination of environmental samples)

Hydrology CPHR Natural radioactive tracers (dating of samples)INSTEC Tracers/radiotracers and non-radioactive tracer technology (hydrologic and

hydrochemical characterization of aquifers)Radiation safety CENTIS Metrology of radiation (measurement of activity)

CNSN Nuclear regulatory organCPHR Radioactive waste management; radioactive decontamination of materials; metrology of

radiation (doses); foodstuffs and scrap radiological surveillance

Table 2. AENTA centers, by sector and area of application.

Source. Based on Influencia de las aplicaciones en la sociedad contemporánea [15].

Page 37: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

news and views

Vol. 27, No. 4, 2017, Nuclear Physics News 35

Research done before 1976 [16]. The second one, from 1996–2015, began with the economic restrictions and the tightening of the embargo, forcing the definitive abandonment of the CEN-Juraguá Project.

First Stage Development [5]Research in Nuclear Physics de-

veloped in two directions (Table 4): theoretical and experimental. The theoretical research, focused on col-lection of nuclear data, the study of nuclear fission and reactor physics, led to an increasing domain of basic nu-clear theories, together with the use of modern models for the calculation of reactions. Part of the experimental re-search was carried out abroad, due to the lack of appropriate national facili-ties, where neutron activation, thermal neutron reflection, and other nuclear analytical techniques were able to as-similate.

In order to develop the first stage in the National Scientific Program, lines of research were determined as: the prediction, collection and valuation of neutron nuclear data from the struc-ture of the nucleus, nuclear reactions, and nuclear fission process.

A milestone in the development of this specialty was the creation of a group of young scientists of excel-lence. It should be noted that, druing 1977–1980, at the Moscow Institute of

Atomic Energy, I.V. Kurchatov (IEA) theoretical work had been carried out using a microscopic approach to the shell model, and investigated the in-fluence of input states on the character of the fluctuations in both the neutron effective sections and the inelastic dispersion in strongly deformed nu-clei [6]. The author of that and other research cited here, F. Castro Diaz-Balart—based in the school of LD Landau—led the creation of a group of qualified researchers in Cuba with young theorists of outstanding trajec-tory, trained in several foreign univer-sities. The works published under the signature of J. R. Fernández Díaz were authored by him.

In the cycle of works [7–9] it can be seen that the theoretical investiga-tions up to 5 MeV were focused on

the study of the interaction among low-energy neutrons in structural materials used in nuclear technology, the development of theoretical meth-ods to calculate the cross-section in the proximity of the reaction thresh-old, and in determining the influence of anharmonism in the calculation of cross-sections and neutron angular distributions. Nuclear fission was also investigated, associated to the low-energy interaction mechanism for the reaction of excited neutrons with the nuclei of the actinides zone.

Also using the IBR-30 reactor of the IUIN of Dubná, experimental in-vestigations were carried out, such as the study of the radiation force func-tion of several strongly deformed transition nuclei and by means of the reaction (n, g) in isolated resonances and the reaction (n, p) by means of resonant neutrons, which allowed the determination of the wave function structure of the composite nucleus states for light nuclei in the 22 < A < 41 zone. With the cooperation of the IAEA, works aimed at measur-ing cross-sections and angular distri-butions of neutron-induced reactions with energy of 14 MeV were done.

Second Stage DevelopmentIt began in 1996 (Table 5) and was

focused on the description of atomic

The scientific activity in the field of nuclear physicsFirst stage

1980—1995Creation of the priority objectives of scientific programs, the required conditions and

infrastructure. Consolidation of leading institutions and groups.Second stage1996–2015

Reorientation of science programs and innovation activities toward: improvement of non-energy nuclear applications; other related applications and existing

fundamental studies of greater impact.

Table 3. Scientific activity in the field of nuclear physics.

First stage research in nuclear physics Theoretical Experimental ● Nuclear data ● Neutron activation ● Study of nuclear fission and the physics ● Reflection of thermal neutrons of reactors ● Other nuclear analytical techniques ● Basic nuclear theories ● Modern models for the calculation of

neutron-induced nuclear reactions within a broad interval of nuclei and energies

● Physics-neutron and dynamic calculations of reactors

Table 4. Development of the first stage.

Page 38: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

news and views

36 Nuclear Physics News, Vol. 27, No. 4, 2017

nuclei as complex systems; the study and the generalized description of the excited nuclei and their mechanisms of nuclear relaxation; as well as in the deformed nuclei zone.

Regarding applied and experimen-tal Nuclear Physics, projects were as-sociated with development of nuclear methods of analysis and also used to model and simulate nuclear and radio-active processes, and to collect nuclear data for nuclear techniques and others. Among the results obtained, we can mention the characterization in the sugar agroindustry in environmental studies and on the dosage optimiza-tion studies to be administered [10]. In the past decade, studies were devel-oped in the modeling and simulation of experimental facilities, the level of heavy metals pollution in marine sediments and in urban soils of impor-tant cities in the country [11, 12], and the fission of light stable and weakly linked exotic nuclei and the influence of break-up process on the fission of weakly linked nuclei [13].

In recent years, young nuclear physicists have begun work on High Energy Physics linked to the ALICE experiment of the Large Hadron Col-lider (LHC) at CERN. The main re-sults in this line have been obtained and characterized in the Inner Track-ing System (ITS) of the ALICE exper-iment, by the reconstruction of traces produced by radiation beams [14].

ConclusionsThe experience of the Cuban Nu-

clear Program confirms that a small country with limited resources, in ad-dition to the appropriate transfer of equipment and knowledge from in-dustrialized nations, can only hope to implement a nuclear energy peaceful program if it is able to create the nec-essary infrastructure, train staff, and

develop a coherent R&D program of nuclear sciences and technologies.

The magnitude of the CEN-Jura-guá venture also presents a cultural balance manifested in the preparation level, experience, and technological maturity reached by its professionals, technicians, and executives of many specialties.

Nuclear techniques and radioactive sources are currently applied in many institutions from different sectors. There is also an infrastructure that includes applications in agriculture, food, sugar, mining, and industry in general. It is necessary to emphasize the application achievements of the public health system, which includes services to the biotechnology industry and preclinical and clinical research on pharmaceuticals.

Finally, a key factor has been to count on the valuable cooperation with international nuclear research centers and the IAEA. Nuclear Phys-ics has also provided greater visibility for Cuban science at the international

level through thousands of publica-tions in renowned journals, obtained patents, and the awards granted by the ACC and other national and interna-tional institutions.

References 1. F. Castro Díaz-Balart, Energía Nu-

clear y Desarrollo (La Habana. Ed. Ciencias Sociales, 2da edición 1991, por Colihue, Argentina).

2. F. Castro Díaz-Balart, Nuclear En-ergy: Environmental Danger or Solu-tion for the 21st Century (Ed. Lagos S.A., Monterrey, México, 2011) (previ-ous editions in different languages and countries).

3. A. Díaz García, 2006. Rev. Nucleus 40 (2006) 6.

4. O. García and J. Medina, Nucleus 37 (2005) 39.

5. F. Castro Díaz-Balart, Nucleus 7 (1989) 15.

6. J. R. Fernández Díaz and V. K. Sirot-kin, Nucl. Phys. A 312 (1978) 17.

7. J. R. Fernández Díaz and R. Cabezas Solórzano, J. Phys. G 9 (1983) 1115.

8. J. R. Fernández Díaz and Cabezas Solórzano, 1986. Proc. Int. Cont. on

Second stage research in nuclear physicsTheoretical Experimental● Atomic nuclei as complex systems● Excited nuclei● Mechanisms of nuclear relaxation● The impact of the nuclear structure on

heavy ion reactions near the Coulomb barrier

● Violation of parity in nuclear reactions near deformed nuclei zone

● Development of nuclear methods of analysis in several areas of interest

● Collection of nuclear data for nuclear techniques

● Characterization of zeolite and oil reserves

● Environmental studies for the sugar agroindustry

● Studies on the optimization of the medical dosage to be administered

● Research in the field of nuclear fission reactions

● Works on the high energy physics linked to ALICE experiment on (LHC) at CERN

Table 5. Development of the second stage.

Page 39: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

news and views

Vol. 27, No. 4, 2017, Nuclear Physics News 37

Nuclear Physics, (Harrogate, United Kingdom VI, 1986), 421.

9. J. R. Fernández Díaz, R. Cabezas Solórzano, and R. López Méndez, Yad Fyz. 41 (1985) 1508.

10. C. A. Sánchez Catases et al. 2003. Alasbimn Journal 6 (2003) 22.

11. J. T. Zerquera et al., Radiat. Prot. Do-sim. 121 (2006) 168.

12. O. Díaz Rizo et al. J. Radioanal. Nucl. Chem. 292 (2012) 81.

13. P. Silveira Gomes et al., Physical Re-view C: Nuclear Physics 71 (2005) 017602.

14. K. Aamodt et al. Eur Phys J. C 71 (2010) 1655.

15. A. Díaz García. Rev. Nucleus 40 (2006) 6–14.

16. Pérez Rojas et al., Estado actual de las ciencias físicas en Cuba. In las Cien-cias Básicas: Examen preliminar de su situación actual en Cuba y a nivel mundial. (1976) 45–46.

FIDEL CASTRO DÍAZ-BALART

Academy of Sciences of Cuba

Please contact Maureen Williams for advertising opportunities: [email protected]

NeutronNews FEATURING:

What Happened at Les Houches in 1954

Volume 28, Issue 3July/August/September 2017

IN THIS ISSUEHorace & SpinW workshop at ISIS, UK

Neutrons greet Faraday at WarwickHigh Brilliance compact accelerator driven sources for EuropeJDN21017, the French user meeting on the Mediterranean coast

November/December 2017 • Vol. 30, No. 6

FELs Status:A Look Ahead to 2018

www.tandfonline.com

Page 40: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

in memoriam

38 Nuclear Physics News, Vol. 27, No. 4, 2017

Arthur Kerman, who joined the Massachusetts Institute of Technology (MIT) physics faculty in 1956 and re-mained a key contributor there for six decades, passed away in May 2017 at the age of 88. He was a leader in theo-retical nuclear physics, making signifi-cant advances in the understanding of both nuclear structure and nuclear reac-tions, while always being grounded in experimental reality. Specific nuclear structure contributions included appli-cation of the Hartree-Fock approach to deformed nuclei and elucidation of the Coriolis effect and pairing correlations in nuclei, while he advanced nuclear re-action theory on issues such as interme-diate structure and isobar analog states. He also served as a member of Presi-dent Reagan’s science advisory council and over many decades as a key advisor to the Department of Energy and sev-eral of its national laboratories, mate-rially influencing laboratory directions from basic research to large nuclear security facilities.

Much more will be written about Arthur’s research and advisory roles in academia, national labs, and govern-ment, appropriate to his considerable reach and influence. However, we also remember Arthur for his infectious en-thusiasm and engagement with any and all physics challenges, his support for

and mentoring of young physicists, and his innate ability to create a sense of community among physicists of differ-ent ages and interests.

The accompanying photo captures Arthur’s favorite professional activ-ity, and he spend a lot of time at it: at a chalkboard with chalk in hand, cal-culating and talking physics with a colleague. Indeed, some have alleged that Arthur was not deeply familiar with any other writing instrument! I first saw this when I was visiting Los Alamos during the summer of 1972 as a freshly minted Ph.D. Arthur was by then a well-established leader in the field but nevertheless simply showed up in my little office, went to the board, and started a peer discussion on quasi-elastic electron scattering from nuclei, a subject that he had heard was part of my doctoral research. Arthur was supervising an MIT doctoral thesis on the topic in anticipation of the research program at the Bates laboratory, a DOE next generation electron accelerator that would soon be completed and op-erated by MIT. A lively discussion led to an outcome that I came to observe over the next forty years as typical of such “Arthur interactions” with an un-countable number of colleagues: we both learned something! My observa-tion post was an office across the hall in

the MIT Center for Theoretical Physics and, as a mutual colleague Mike Camp-bell has stated, “The world is a little more empty and quiet without Arthur in it.” His physics spontaneity and en-thusiasm is missed at his many regular stops. As Director of the Center, Arthur was incomparable in nurturing a com-munity approach to physics!

Arthur’s influence on the com-munity—and on me personally—had many other dimensions as well. As a starting faculty member at MIT, he joined the post-Sputnik Physical Sci-ence Study Committee that developed a radically different way of teaching high school physics compared to the norm at that time. I was one of the many ben-eficiaries, and indeed it was that course that led to my commitment, and pre-sumably that of many others, to physics in college and beyond. And pivoting to the last few years, Arthur was a regu-lar visitor to the Department of Energy when I served as Secretary. He never had to announce his visit—the buzz was sufficient to alert me that he was in the building. Invariably a chance to connect with him led to some insight on what could be done in the laboratory complex to advance the physics enter-prise and the nation’s interest.

Arthur was dedicated to his fam-ily, wife Enid and five children, who welcomed Arthur’s “physics family” as an extension. They were unfazed by Arthur’s enthusiastic “theories,” such as the attractions of pulling a camping trailer across the country for a visit to Livermore or buying a distant restau-rant, generally proving that theory and practice are not the same thing. We join them in deeply missing Arthur but cel-ebrating a remarkable life.

ErnEst J. Moniz Professor Emeritus, MIT, Cambridge,

Massachusetts, USA Former U.S. Secretary of Energy

In Memoriam: Arthur Kerman (1929–2017)

Arthur Kerman

Page 41: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

in memoriam

Vol. 27, No. 4, 2017, Nuclear Physics News 39

Peter Paul, distinguished nuclear physicist and eminent science admin-istrator, passed away in March 2017 at the age of 84. Born in Dresden, Ger-many, he received his doctoral degree in nuclear physics from the University of Freiburg in 1962. Shortly afterward he moved to Stanford University as Research Associate and became only a few years later Professor and one of the founding members of the nuclear structure laboratory at Stony Brook University in 1967. Under his lead-ership the team there became one of the most influential nuclear physics groups in the United States.

His research interests ranged from nuclear structure physics to accelera-tor physics, heavy ion physics at low and high energies, and, in his later years, to neutrino physics and he made a strong impact everywhere. In partic-ular, he made lasting contributions to our understanding of the structure of giant resonances in nuclei. He also led, jointly with Gene Sprouse, the design and construction of the Stony Brook superconducting linear accelerator for heavy ions, the first such machine at a university laboratory.

From the early 1980s on he also be-came very influential as a science ad-ministrator. He was a member of the

U.S. Nuclear Science Advisory Com-mittee (NSAC) from 1980–1983. And as head of NSAC from 1989–1992 he directed the development of the 1989 NSAC Long Range Plan, with a key recommendation that a Relativistic Heavy Ion Collider (RHIC) be the highest priority for new construction in the U.S. nuclear physics program. RHIC was completed a decade later and has produced a stream of outstand-ing and transformational physics re-sults in quark-gluon plasma research. Peter Paul was Chair of the Stony Brook physics department twice. In 1992 he became Distinguished Ser-vice Professor.

In 1998, Peter Paul was appointed Deputy Director for Science and Technology at Brookhaven National Laboratory and served, concurrently, as Interim Director of the Laboratory from 2001–2003. During his tenure, RHIC began operating, and several other major projects started. After this time he joined the Stony Brook neu-trino group and participated actively in research within the international T2K collaboration. He served the Stony Brook University administra-tion until recently as Associate Vice President for Brookhaven Affairs and had become Distinguished Service and Research Professor Emeritus in the spring of 2015.

Despite his many commitments and duties in the United States Peter Paul never lost his connection to Europe and, in particular, Germany. He spent extended and fruitful research periods in Heidelberg in 1974, as awardee of the Senior Humboldt Research Award in 1983 at the Max-Planck-Institut für Kernphysik in Heidelberg, and at Giessen University in 1992. His strong connections to Germany led to mem-bership in many advisory boards and committees. In particular, he played a

key role in the establishment of major new scientific projects as member of the German Wissenschaftsrat’s “work-ing group for large infrastructures,” where the seeds for the accelerator projects XFEL and FAIR were sown. From 2001–2007 he was member of the Helmholtz Senate and his advice was very important for the implemen-tation of these major programs as well as for the restructuring and reorienta-tion of several Helmholtz Research centers.

Peter Paul received numerous awards for this scientific work, among them an A.P. Sloan Fellowship, the Fellowship of the American Physi-cal Society Fellow and of the British Institute of Physics, an honorary doc-toral degree of Moscow State Univer-sity and the Order of Merit First Class (Bundesverdienstkreuz) from the Ger-man Government. In 2002, he was se-lected as Long Island Entrepreneur of the Year and in 2015, he was inducted into the Long Island Technology Hall of Fame.

One of his crucial contributions to physics was the curiosity in and complete dedication to scientific re-search with which he inspired many younger members of the community. His boundless energy and infectious enthusiasm to attack new projects are legend. Beyond his profession, Peter Paul had a broad range of interests: He loved reading, sailing, traveling, and music. He will be missed.

Peter Braun-Munzinger

EMMI, GSI, Darmstadt, and Physikalisches Institut, Universitaet

Heidelberg, Heidelberg, Germany

Volker Metag, ii and Johanna Stachel

Physikalisches Institut, Universitaet Giessen, Giessen, Germany

In Memoriam: Peter Paul (1933–2017)

Peter Paul

Page 42: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

in memoriam

40 Nuclear Physics News, Vol. 27, No. 4, 2017

Professor Adriaan van der Woude, a renowned nuclear physicist, passed away on 20 August 2017. In him we lost a kind colleague and excellent mentor, but above all a good friend. In tribute to his memory we recount his career and achievements.

Adriaan was born on 3 June 1930 in Westerbroek near Groningen where he did his university studies and near to Haren, where he lived most of his life. He started his studies in 1948, finished his M.Sc. equivalent in 1954, and completed his Ph.D. under the su-pervision of Prof Henk Brinkman in 1960 on the thesis “Construction and operation of betatron and cloud cham-ber,” a research theme quite different from themes he pursued later in his life.

Following his Ph.D., Adriaan con-tinued working in Brinkman’s group at the Physics Laboratory. He was at the start of the plans to establish the KVI, proposed by Brinkman and his group. During the period 1961–1967, Adriaan was strongly involved in the planning and acquisition of the Philips

AVF cyclotron and the preparation of its scientific program. During the pe-riod 1963–1965, he went on leave to Oak Ridge National Laboratory where he participated in and initiated re-search in several subfields of nuclear and atomic physics research (e.g., K-shell ionization in atomic collisions, few-body problems, and production and scattering of polarized protons). In August 1967, he left Groningen again for Oak Ridge as permanent staff member working on these di-verse topics.

In 1972, Adriaan returned to the newly established KVI as a Senior Sci-entist taking active part in the devel-opment of its research programs and helping build an excellent scientific atmosphere. At KVI, his research con-centrated on Giant Resonance studies, for which he became internationally known. He also pursued some of his earlier research interests. In particular, his work on giant resonances, together with one of us (MNH), allowed the KVI to play a leading role worldwide and gave his Ph.D. students and post-docs the opportunity to perform high-impact research.

Adriaan was appointed professor at the University of Groningen in 1980 and was associate director of KVI for several years. In that period, he played a key role in defining the KVI’s future plans. He facilitated the collaboration with IPN-Orsay to build the super-conducting AGOR-cyclotron, which has been operational since 1996. Dur-ing the construction period, he led the project, together with Sydney Galès, and spent a sabbatical year in Orsay for that purpose.

Adriaan served the community in several ways. He became a member of the NuPECC Board and first Chair of the NPN Editorial Board in 1990. Adriaan recognized the importance of outreach. He started (together with Jean Vervier) and actively pursued the PANS initiative. He became Chair-man of the Groningen Royal Physical Society in 1990. For his achievements he was elected fellow of the American Physical Society and later decorated as Officer in the Order of Orange-Nassau.

Apart from his many publications Adriaan (co-)authored three books: an extensive monograph on giant reso-nances, a history of KVI, and a popu-lar science book on radioactivity.

In July 1995, Adriaan retired and on this occasion the international “Gi-ant Resonances” Conference was held in Groningen to commemorate his many contributions to the field.

In his work and contacts, Adriaan was very easy to get along with. He appreciated others and was a very good listener although he clearly had his own opinions. He was collegial and friendly, with a high sense of cor-rectness and integrity. Colleagues re-ally enjoyed working with him. He had an inquisitive, proper, and criti-cal view of things. His colleagues and many students will fondly remember him.

Sytze BrandenBurg, MuhSin n. harakeh,

and rolf h. SieMSSen KVI-CART, University of Groningen,

Groningen, The Netherlands

In Memoriam: Adriaan van der Woude (1930–2017)

Adriaan van der Woude

Page 43: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

calendar

2018February 1–2

Pisa, Italy. Probing fundamental symmetries and interactions by low energy excitations with SPES-RIBs

https://agenda.infn.it/conferenceDisplay.py?confId=13891

February 19–25Bormio, Italy. BORMIO-2018:

The IV Topical Workshop on Mod-ern Aspects in Nuclear Structure

https://sites.google.com/site/wsbormiomi2018/

February 26–March 2GSI Darmstadt, Germany. NU-

STAR Annual Meeting 2018https://indico.gsi.de/

conferenceDisplay.py?confId=5843

March 13–15GSI Darmstadt, Germany.

NARRS2018 - Nuclear Astrophysics at Rings and Recoil Separators

http://exp-astro.physik.uni-frankfurt.de/meetings/narrs/

April 17–20Groningen, The Netherlands.

ENSAR2 Town Meetinghttp://www.ensarfp7.eu/

May 13–18Marianske Lazne, Czech Repub-

lic. RadChem 2018 – 18th Radio-chemical Conference

http://www.radchem.cz/

May 22–25Catania, Italy. IWM-EC 2018

International Workshop on Multi facets of Equation of state and Clus-tering

http://www.ct.infn.it/iwm-ec2018

May 22–25Padova, Italy. 9th International

workshop on Quantum Phase Tran-sitions in Nuclei and Many-Body Systems

https://agenda.infn.it/conferenceDisplay.py?confId=13348

May 27–June 1Giens, France. EURORIB 2018

- European Radioactive Ion Beam Conference

https://eurorib2018.sciencesconf.org/

June 4–8Matsue, Japan. 10th Interna-

tional Conference on Direct Reac-tions with Exotic Beams (DREB) 2018

http://indico2.riken.jp/indico/conferenceDisplay.py?confId=2536

June 7–12Kraków, Poland. MESON2018

15th International Workshop on Meson Physics

http://meson.if.uj.edu.pl/

June 11–14Ann Arbor, MI, USA. SORMA

2018http://rma-symposium.engin.

umich.edu/

June 11–15Aachen, Germany. 7th Interna-

tional Symposium on Symmetries in Subatomic Physics (SSP 2018)

hhttps://indico.cern.ch/event/651952/

June 18–22Ohrid, Macedonia. Sixth Inter-

national Conference on Radiation and Applications in Various Fields of Research (RAD 2018)

http://www.rad-conference.org/

June 24–29Brasov, Romania. Nuclear Pho-

tonics 2018http://nuclearphotonics2018.

eli-np.ro

July 1–6Caen, France. SHIM - ICACS

2018http://www.shim-icacs2018.org/

July 9–13Caen, France. FB22 - XXII Inter-

national Conference on Few-Body Problems in Physics

https://fb22-caen.sciencesconf.org/

August 5–10East Lansing, MI, USA. Nuclear

Structure 2018https://indico.fnal.gov/

conferenceDisplay.py?confId=15187

August 11–17Grapevine, TX, USA. CAARI

2018http://www.caari.com/

August 26–September 2Zakopane, Poland. Zakopane

Conference on Nuclear Physics 2018 “Extremes of the Nuclear Land-scape”

http://zakopane2018.ifj.edu.pl/

September 2–7Bologna, Italy. EUNPC 2018http://www.eunpc2018.infn.it/

September 10–15Petrozavodsk, Russia. IX Inter-

national Symposium on Exotic Nu-clei, EXON-2018

http://exon2018.jinr.ru/

September 16–21CERN Geneva, Switzerland.

EMIS2018https://indico.cern.ch/

event/616127/

November 13–17Tsukuba, Japan. 8th Interna-

tional Conference on Quarks and Nuclear Physics

http://www-conf.kek.jp/qnp2018/

More information available in the Calendar of Events on the NuPECC website: http://www.nupecc.org/

Page 44: Nuclear Physics News - NuPECCol Vol. 27, No. 4, 2017, Nuclear Physics News 3 Scientific inquiry has been a global human activity since the dawn of history. We scientists are citizens

Subscribe now to receive every issue.

Pleasephotocopythisformandmailto:

Taylor&Francis-NuclearPhysicsNewsSubscriptions530WalnutStreet,Suite850Philadelphia,PA19106USA

Tel:+12156258900Fax:+12152070050

NuclearPhysicsNews:ISSN1050-6896Quarterly,Volume27(2017)

☐InstitutionalSubscription(print+online)-£737/€975/$1223☐PersonalSubscription-£88/€120/$146☐ComplimentarySubscriptionfornuclearphysicistsfromcontributingcountries

BILLTO/SHIPTO:CHARGE:☐VISA☐MC☐AMEXPleaseprint:

Name___________________________________Card#__________________________________Institution______________________________Exp.Date_______________________________Address________________________________Signature________________________________________________________________________Telephone______________________________Requiredforcreditcardpurchase.City____________________________________P.O.#___________________________________State___________________________________Date____________________________________Zip/Post_______________________________Country________________________________E-mail________________________________☐CHECKORMONEYORDERENCLOSEDMakecheckspayabletoTaylor&FrancisinUSfundsonly.