Maria J. G. Borge , CERN, PH-Dept

Exploring the Nuclear Landscape

Maria J. G. BorgeISOLDE-PH, CERN(Isotope Separator On-Line)IEM-CSIC, Madrid

ISOLDE – High-lights and HIE-ISOLDE

19921998

HIE-ISOLDE

ISOLDE

2008

Hot Topics in Nuclear Physics

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Physics at the Femtometer scale

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Open Questions in Nuclear Physics

Observables:Ground-state properties: mass, radius, J, μ, Q momentsHalf-lives and decay modesTransition probabilitiesCross sections

Main models:Shell model (magic numbers)Mean-field models (deformations)Ab-initio approaches (light nuclei)

How are complex nuclei built from their basic constituents? strong interaction in nuclear medium • How to explain collective properties from individual nucleon behavior? collective versus individual • How do regular and simple patterns emerge in the structure of complex nuclei? symmetries

LRP2010

Production of Radiactive Beams @ ISOL Facilities

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ISOLDE Facility

intensity (2uA -> 6uA ) energy (1.4 -> 2GeV)

ISOLDE is the CERN radioactive beam facilityNuclei produced via reactions of high intensity high energy proton beam with thick and heavy targetsProvides low energy or post-accelerated exotic beams

PSB upgrade (2018)

ISOLDE at CERN

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LHC

Produced Nuclei: ISOLDE 45 y Experience

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Over 20 target materials and ionizers, depending on beam of interest operated at high temperatureU, Ta, Zr, Y, Ti, Si, …3 types of Ion-sources: Surface, Plasma, Laser> 700 nuclides of over 70 chemical elements produced

Target

ISOLDE today offers the largest range of available isotopes of any ISOL facility worldwide.

ISOLDE Physics TopicsMany beamsGood beam purity and quality

Best in the World!High intensity

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Nuclear PhysicsNuclear Decay Spectroscopy

and ReactionsStructure of Nuclei

Exotic Decay Modes

Atomic PhysicsLaser Spectroscopy and

Direct Mass Measurements

Radii, Moments, Nuclear Binding Energies

Nuclear Astrophysics

Dedicated Nuclear Decay/Reaction Studies

Element Synthesis, Solar Processes

f(N,Z)

Fundamental PhysicsDirect Mass Measurements,

Dedicated Decay Studies - WICKM unitarity tests, search for b-n correlations, right-handed

currents

Applied PhysicsCondensed matter physics and

Life sciences Tailored Isotopes for

Diagnosis and Therapy MEDICIS Project

Determination of the atomic properties of Astatine

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16150 16200 16250 16300 16350

0

10

20

30

ion

curr

ent

(pA

)

wavenumber (cm-1)

10 36

Determination of ionising potentialIdentification of new atomic transitionsComparison with atomic theoryScan of ionizing laser: converging Rydberg levels allow precise determination of the IP

IP(At) = 9.31751(8) eVNature Com. 14May2013DOI 10.1038

M. Seliverstov, V. Fedoseev team

ISOLDE collaborates with the Short-Lived Nuclei Laboratory which is based on the ISOL facility IRIS at PNPI since 1999.

Experimental hall

Target stationsHRS & GPS

Mass-sep.HRS

ISCOOLRILISREX-ISOLDE

PS-Booster 1.4 GeV protons

3×1013 ppp

ISOLTRAP

CRIS

COLLAPS

NICOLE

MINIBALL and T-REX

WITCH

Travelling setups

Travelling setups

Post-accelerated beams

Collection points

TAS

Decay spectroscopyCoulomb excitationTransfer reactionsLaser spectroscopyBeta-NMRPenning trapsApplications: Solide state Life Science

Beams of 30-60 keVBeams of 3 MeV/u

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COLLAPS – Ne charge radiiLaser spectroscopy & Massses

Geithner et al, PRL 101, 252502 (‘08)Marinova et al, PRC84, 034313 (‘11)

Intrinsic density distributions of dominant proton FMD configurations

ISOLTRAP: High-precision mass of 82Zn

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Nuclear structure: N=50 shell closure

Astrophysics: r-process path

Astrophysics: neutron star structure

Combined ISOLDE technical know-how: neutron-converter, quartz transfer line, laser ionisation

Its determination is important for modelling of the crust of neutron stars , PRL110 (2013) 04110

Bmq

c n

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CERN Courier, 53, n 3, 2013 D. Rodriguez, U. Granada

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The Magic Number N=32

Nature 498 (2013) 346

WITCH

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M. Beck et al., Eur. Phys. J. A47 (2011) 45M. Tandecki et al., NIM A629 (2011) 396S. Van Gorp et al., NIM A638 (2011) 192

June 2011 data

Energy spectrum of recoiling ions with a retardation spectrometer Use a Penning trap to create a small, cold ion bunch

Weak Interaction Trap for Charged particles -> fundamental studiesGoal: determine bn correlation for 35Ar with (a/a)stat 0.5 %

REX-ISOLDE

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Total efficiency : 1 -10 % 1+ to A/Q = 3 – 4.5Tested A/q = 2

Halo Nuclei & Reactions

1Hn

2H

3He 4He

6Li 7Li 8Li 9Li 10Li 11Li

Common “Structural” properties Rather inert core plus one or two barely

unbound extra neutrons Extended neutron distribution, large

“radius”. “halo” Very few excited states –if any.

Reaction properties at near-barrier energies:Is the Optical Model able to describe the scattering of the halo systems ? Strong absorption in elastic channel Large cross section for fragmentation They are easily polarizable.

Reaction mechanisms and Nuclear effects

of halo nuclei need to be understood

6He

Dobrovolsky et al, NPA766 (2006) 1

7Be 8Be 9Be10Be 12Be11Be 14Be

2n-halo

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Elastic scattering of halo nuclei near the Coulomb barrier

10Be+64Zn11Be+64Zn

10,11Be+64Zn

CDCC calculations

Experimental elastic cross section. reproduced only taking into account

coupling to continuum via the Coulomb and nuclear interactions

Di Pietro et al. Phys. Rev. Lett. 105,022701(2010) Catania, IEM-CSIC, Huleva, Sevilla Collaboration

Scattering of 11,9Li on 208Pb around the Coulomb Barrier

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Elastic Scattering

Scattering process dominated by:- Dipole couplings (coulomb + nuclear)- Coupling to continuum- Good description in a 4-body model Cubero et al, PRL109 (2012) 262701IEM-CSIC, Huelva, Seville Collaboration

9Li

9Li

11Li

11Li

Competing process with Elastic Scattering for loosely bound systems

ECM = 23.1 MeV below Coulomb Barrier

ECM = 28.3 MeV @ the Coulomb Barrier

Direct Breakup 2n-Transfer

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Why to study the N=Z 72Kr Nucleus?

rp-process in N=Z nuclei & A=70-80 region

Nuclear structure:o Shape coexistence in the mass region was first proposed for 72Se [Ham74].o 72Kr ground state is predicted to be oblate [Dic72] and [Naz85].o First excited 0+ state in 72Kr found to be a shape isomer [Bou03].o Possibility of study np-pairing effects as 72Kr belongs to N=Z line.

[Ham74] J.H. Hamilton et al., Phys. Rev. Lett. 32, 239 (1974)[Dic72] F. Dickmann et al., Phys.Lett. 38B, 207 (1972)[Naz85] W. Nazarewicz et al., Nucl. Phys. A435, 397 (1985)[Bou03] E. Bouchez et al., Phys. Rev. Lett. 90, 082502 (2003)

Nuclear astrophysics:o 72Kr “waiting point" in rp process.

73Rb is unbound

o β decay competes with 2p capture.

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Coulomb excitation of 72Kr

Oblate 72Kr expected

The technique

Coulex Spectra - number of counts in 710 keV peak depends on the shape of 72Kr

Doppler Corrected for 104Pd target excitation

Doppler Corrected for 72Kr projectile excitation: 150 counts in 710 keV line

Use of submicron Y203 material for target => Yield increase x 10

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TAGS @ISOLDE: The case of 72Kr

Briz, ISOLDE Workshop 2012

o Conversion electron studies to determine the multiplicities of the low gamma transitions

The B(GT) distribution favours oblate deformation!

P. Sarriguren, Phys. Rev. C 79, 044315 (2009)

o B(GT) obtained by measuring the intensity of the full gamma de-excitation cascade from each fed level to the ground state.

IEM-CSIC, Strasbourg, Surrey, Valencia

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Octupole correlations enhanced at numbers: Z or N=34, 56, 88, andN= 134. Observed Z≈88 & N≈134

Microscopically driven...

Intruder orbitals of opposite parity and ∆J, ∆L = 3 close to the Fermi level

Coulomb excitation to directly access E3 transition strengths

B(E3) 30 s.p.u. gives significant ≳β3

Searching for pear-shaped nuclei at ISOLDE

λ = 2

λ = 2

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L. P. Gaffney, et al. (2013). Nature, 497(7448), 199–204. doi:10.1038/nature12073Hangout with CERN: Going pear-shaped (http://www.youtube.com/watch?v=x8Jdu9O2RhU&feature=em-uploademail) MORE than 1000 viewers

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Physics program @ REX

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50

20 40 50 82184,186,188HgProbing shape coexistence

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70Se, shape coexistence, Hurst PRL 200796Sr, 88Kr, 92Kr

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122,124,126Cd138,140,142,144Xe140,148,150Ba

110Sn; Cederkäll, PRL 2007106,108Sn, Cederkäll, PRL 2008

Evolution of collectivity around 132 Sn

67,69,71,73Cu, Stefanescu et al., PRL 200868,70Cu, isomeric 68Cu, Stefanescu , PRL 2007

74,76,78,80Zn Probing large scale shell model, Van der Walle, PRL2007

30,31,32Mg, Niedermaier PRL2005, H. Scheitd(30Mg,p)31Mg, K. Wimmer, PRL 2010

REX-ISOLDE started in 200172 different beams already used at REX- ISOLDE of 700 available!

Halos & clustersd(8Li,p)9Li*; d(9Li,p)10Li…

The Limitations of REX-ISOLDE (E 3.1 MeV/u) Very limited energy flexibility Operation restricted to pulsed mode Bunch length is not flexible Extension to higher energy is difficult

222,224Ra; 220,222RnProbing Pear ShapeNature 497 (2013)199

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Near Future: HIE-ISOLDE projectEnergy Upgrade:The HIE-ISOLDE project construction of the SC LINAC to upgrade the energy of the post-accelerated radioactive ion beams to 5.5 MeV/u in 2015 and 10 MeV/u by 2017

Intensity Upgrade:The design study for the intensity upgrade, also part of HIE-ISOLDE, started in 2011, and addresses the technical feasibility and cost estimate for operating the facility at 10 kW once LINAC4 and PS Booster are online.

• Approved Dec 2009• Offically started Jan 2010• Yacine Kadi project Leader• Budget 40 M$

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Physics addressed with HIE-ISOLDE / IS564Study of the unbound proton-rich nucleus 21Al with resonance elastic and inelastic scattering using an active target (USC, IEM, MAYA Collaboration)

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ExperimentTo measure resonant elastic, 20Mg(0+), and inelastic, 20Mg(2+), scattering using MAYA to determine energy, spin and parity of the 21Al excited states.

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Summary and outlookThe future of ISOLDE is bright. It will restart in June 2014 with the low energy program.

With more than 40 year of operation ISOLDE remains as the pioneer ISOL-installation both at the level of designing new devices and production of frontier Physics.

Post accelerated beams up to 5.5 MeV/u for the wide range of nuclei produced at ISOLDE will be available from Autumn 2015.

HIE-ISOLDE will be the only next-generation radioactive beam facility (as identified by the NuPECC LRP) available in Europe in 2015, and the most advanced ISOL facility world-wide.

Welcome to propose challenging experiments!

Thanks for your attention !