xy positionfrom LYCCA

Slowed down beams - new perspective for GOSIA

scattering experiments at relativistic energies

abrasion

projectile

target nucleusablation

projectile fragment

SISUNILAC

FRS

Production, Separation, Identification

TPC-x,y position @ S2,S4

Plastic scintillator (TOF) @ S4

MUSIC (ΔE) @ S4

Standard FRS detectors

FRagmentSeparator

Scattering experiments at 100 AMeV

56Cr, 100MeV/u

56Cr

Z

A/Q

86Kr, 480MeV/u

standard scintillator (SC21) finger segmented detector

104Sn fragments using 124Xe at 793 MeV/u

high rate at S2 ~106 s-1

~2400 % more tracking efficiency good A/Q resolving power

Frederic Ameil

new digital readout

56Cr, 100MeV/u

relativistic Coulomb excitation

86Kr, 480MeV/u

197Au-target

exp. observables:Z, A, θ

RIB from FRS

secondary197Au target

DSSSD DSSSD

CsI

CsI

time-of-flight

(x,y,ΔE) (x,y,ΔE)

diamond/plastic

Lund-York-Cologne CAlorimeter

Scattering experiments at 100 AMeV

Rare ISotope INvestigation at GSI

EUROBALL Cluster Detectors Miniball: HPGe segmented detectors

HECTOR Large 14.5 x 17 cm BaF2 Detectors

CATE : ΔE-E telescope event by event beam identification

Coulomb Excitation at Relativistic Energy

New Shell structure at N>>Z Relativistic Coulomb excitation of nuclei near 100Sn Triaxiality in even-even core nuclei of N=75 isotones E1 Collectivity in neutron rich nuclei 68Ni

beam

nucleus σ (mb)

56Cr 91

108Sn 314

136Nd 338 / 2180

εγ = 3%ΔEγ = 20 keV

EUROBALL Cluster Detectors Miniball: HPGe segmented detectors

HECTOR Large 14.5 x 17 cm BaF2 Detectors

CATE : ΔE-E telescope event by event beam identification

beam

Rare ISotope INvestigation at GSI

εγ = 3%ΔEγ = 20 keV

VC

cmP

av

QeZL

14 2

02

max

angular momentum transfer:

2+ state → collective strength

High-energy Coulomb excitationtriaxiality in even-even nuclei (N=76)

21+→0+

22+→21

+

22+→0+

22+→21

+

22+→0+

First observation of a second excited 2+ state populated in a Coulomb experiment at 100 AMeV using EUROBALL and MINIBALL Ge-detectors.

shape symmetry collective strength

T.R. Saito et al. Phys.Lett. B669 (2008), 19

)3(sin89

)3(sin231

)3(sin89)3(sin

720

)02;2(

)22;2(

2

2

2

2

1

12

EB

EB

)3(sin89

)3(sin231

)3(sin89

)3(sin231

)02;2(

)02;2(

2

2

2

2

1

2

EB

EB

3sin893

3sin893

)2(

)2(2

2

1

2

E

E

Slowed down beamsexperimental set-up

64Ni 700 AMeV

109 pps 107 pps 3∙106 pps 105 pps

62Co ~ 13 AMeV

62Co 250 AMeV

VC

Slowed down beamsbeam characteristics

62 Co

250 AMeV

62 Co

~ 13 AMeV

ΔEnergy5.2 AMeV

Δθ35 mrad

Slowed down beamsbeam energy measurement

targetdegrader

electrostatic mirror + MCP detector

position resolution ~ 1 mm time resolution ~ 100 ps

TPC-1 TPC-2 SC41 (x1 y1 t1) (x2 y2 t2)

12

2/311 /

78.2/

ss

AE

t

AE

(x3 y3 t3)

experimental results:velocity βbeam energy E/A1

scattering angle θcm

Classical Coulomb trajectoriesbasic concept

1cosh war

Hyperbolic trajectory:

ε = sin-1(θcm/2) eccentricity of orbit

wwv

at

sinh

distance of closest approach:

impact parameter:

angular momentum :

2

θsin1

a )(θ D cm1-

cm

2

θcot

a b cm

2cot cmL

100 AMeV

Classical Coulomb trajectoriesdistance of closest approach

100 AMeV

fmCCR TP 3int Nuclear interaction radius:

CP, CT half-density radii

35.649.4int

TPTP

CCCCR

distance of closest approach:

2sin1 1 cm

cm aD

2sin1

/

72.0 1

21

21

1

21 cmcm AA

AA

AE

ZZD

independent of beam energy

´safe´bombarding energy requirement

100 AMeV

fmCCR TP 3int Nuclear interaction radius:

CP, CT half-density radii

35.649.4int

TPTP

CCCCR

Pure Coulomb excitation requires amuch larger distance between the nuclei”safe energy” requirement

´safe´bombarding energy requirement

< 1% deviation from Coulomb excitation

Dmin

fmCCD TP 5min

Rutherford scattering only if Dmin is large compared to nuclear radii + surfaces:

CP, CT half-density radii

choose adequate beam energy (D > Dmin for all ) limit scattering angle, i.e. select D > Dmin

high-energy Coulomb excitation

100 AMeV

Slowed down beams

targetdegrader

TPC-1 TPC-2 SC41 (x1 y1 t1) (x2 y2 t2) (x3 y3 t3)

2sin1

/

72.0 1

21

21

1

21 cmcm AA

AA

AE

ZZD

ΔEnergy5.2 AMeV

ToF measurement

dd

EdD

sinminmax

00

GOSIA calculation:

weighted with beam energy

Slowed down beams new perspective for GOSIA

P. Boutachkov, E.T. Gregor, F. Naqvi, F. Farinon, J. Gerl, M. Gorska, I. Kojouharov, I. Mukha, C. Nociforo, W. Prokopowicz, S. Pietri, A. Prochaka, H. Schaffner, H. Weick, H.J. WollersheimHelmholtzzentrum für Schwerionenforschung, Darmstadt, Germany

K. Hadynska, P. Napiorkowski, D. PietakUniversity of Warsaw, Warsaw, Poland

P. BednarczykIFJ PAN Krakow, Poland

N.A. KondratyevFlerov Laboratory of Nuclear Reactions JINP, Dubna, Russia

A. JhinganInter University Accelerator Centre, New Delhi, India

R. Janik, P. Strmen,Comenius University, Bratislava, Slovakia

M.A.G. AlvarezCentro National de Acceleradores CNA, Seville, Spain