Rare ISotope INvestigation at GSI Status of the relativistic beam campaign
Introduction
Fast beam physics program
Experimental methods
Status and perspectives
P. Reiter for the RISING collaboration
Workshop: RISING with stopped beams
University of Surrey, March 29 – 30, 2004
RISING introduction
• RISING physics with stopped beams, March 29/30, 2004 Surrey
• GSI Program Advisory Committee January 26/27, 2004 Darmstadt 4 RISING proposals
• Commissioning & first experiments August-October 2003
• GSI Program Advisory Committee June 20/21, 2002 Darmstadt 12 RISING proposals
• Physics with RISING at GSI, March 22, 2002 Orsay • RISING physics with relativistic HI-beams, April 6, 2001 Darmstadt• RISING physics with stopped beams, March 9, 2001 Göttingen• RISING physics with slowed-down beams, April 2/3, 2001 Legnaro• Physics with EUROBALL detectors at GSI, November 23/24, 2000 Darmstadt
High resolution -spectroscopy at the FRS
RISING
• fragmentation and fission of primary beams
• projectile energy 400 – 750 MeV/u
• primary targets: Be or Pb
• Dipoles:
• Identification of fragmentation product (A,Z)
-spectroscopy at secondary target• Channel selection after target (A,Z)
• Tracking before/after secondary target
FRS
RISING approved experimentsNo. Nuclei of Interest
Primary Beam
Spokespersons Experiment Typeapproved
(days)
1 32,34Mg 48Ca P. Mayet2 step fragmentation
lifetime6
2 45Cr, 53Ni, 45Sc, 53Mn 58Ni M. Bentley 2 step fragmentation 7
3 68Ni 86Kr A. Bracco Coulex, E1 strength 7
4 36Ca, 66Fe 86KrH. Grawe,H. Hübel
P. ReiterCoulex, 2+
1 13
5 69Br 78Kr F. Becker 2 step fragmentation 7
6 88Kr, 90Sr, 86Se 238U J. Jolie Coulex, 2+2 10
7 104-112Sn 124XeC. Fahlander
M. GórskaCoulex , 2+
1 7
8 132Sn 238U G. de Angelis Knock-out 5
9 132Xe 136Xe A. Maj Coulex, Angular Distr. 3
10 134Te 136Xe K.-H. Speidel Coulex, g-factor 7
11 136Nd 144Sm T. Saito Coulex 7
12 185,186,187Pb 238UJ. Gerl, A. Andreyev
G.D. Dracoulis2 step fragmentation
lifetime8
Physics program
66Fe
53Ni
32,34Mg
104-112Sn
68Ni
134Te
132Sn
Shell structure of unstable magic- and double magic nuclei
Isospin symmetry at N=Z
50Fe
50Mn
50Cr
46V
46Cr
46Ti
53Co
49Fe
45Cr
53Fe
55Ni
55Co
45V
45Ti43Ti
43Sc
41Ca
41Sc
53Ni
45Sc
42Ti
42Sc
42Ca
f7/2-shell
T= 1/2
T= 1
T=3/2 no excited states
45Cr, 49Fe, 53Ni 69Br
?
Shapes and shape coexistence
2+
3+
185,186,187Pb136Nd
potential energy surface for 186Pb
-decay of the GDR in the Exotic Nucleus 68Ni
• Giant Dipole Resonance (GDR) : basic collective excitation modes
• effective NN interactions
• Evolution of GDR strength in exotic nuclei : • Fine structures • GDR strength at lower energy• astrophysical implications
RISING: relativistic Coulomb excitation (virtual photon scattering) -decay branch: tot ~ 10-3 - 10-2
Relativistic RPA, Vretenar et al.
68Ni 78Ni
58Ni48Ni
experimental methods
Established methods:
• Coulomb excitation - first 2+ states => B(E2) - giant dipole resonance (virtual photon absorption)
• Secondary fragmentation - excited states at higher
spins and excitation energy
RISING new developmentsCoulomb excitation - Low lying states B(E1), B(E2, 0+
gs -> 2+1,2,3)
- 2+ states + angular correlation- 2+ states + g-factor
-decay of the GDR in the Exotic Nucleus 68Ni Excited via Coulomb Excitation-decay of the GDR in the Exotic Nucleus 68Ni
reaction68Ni (400 MeV/A) + natPb (2 g/cm2)
BaF2 for the whole GDR strength function
Ge cluster for the Pygmy part
HECTOR
6 BaF2 detectors efficiency at high energies:
knock-out reactions
Spectroscopic factors: -ray intensity of excited states in the A-1 fragment.
No l-value of ejected nucleon, missing momentum distribution.
Recoil
momentum
-decay of
excited states
132Sn
Shape evolution in n-rich Mg nuclei
Primarybeam : 48Ca
Secondarybeam : 38Si
SIS FRS S4
Secondary fragmentation& lifetime measurement
targets:Au : 3 x 0.3 g/cm2
0.7 mm 2.1 mm
38Si 100 MeV/u
E
2
32Mg , 2
E2
1
32Mg , 1
E1
3
32Mg , 3
E3
RISING timetable 2003
22.4.- 16.5.2003 Cluster shipment
22.4.- 4.8.2003 annealing, assembly, testing and mounting
16.6.- 20.6.2003 assembly of support structure
14.7.- 5.8.2003 VXI-MBS tests (S4)
beam time• Commissioning I• Commissioning II• New Shell Structure at N>>Z • Isospin Symmetry, Coulomb Effects• Coulomb Excitation Near 100Sn
beam132Xe84Kr84Kr58Ni
124Xe
date
Aug 06 – Aug 11
Sep 12 – Sep 21
Sep 22 – Sep 28
Oct 11 - Oct 20
Oct 21 - Oct 27
short term outlook
2004Block 2/2004: March 31 - May 21(Therapy: March 31 - April 30)RISING: May 1 – 18 - E1 strength in 68Ni RISING & HECTOR - Shell structure in N>>Z nuclei
Block 3/2004: July 14 - October 7(Therapy: July 14 - August 13)
Block 4/2004: Oct. 27 – Dec. 16(Therapy: Oct. 27 – Nov. 26)RISING: Nov. 29 – Dec. 12 RISING & MINIBALL
2005 Winter: RISING & MINIBALL
Increased -efficiency: 4 - 10 %
SIS beam time is shared between:• HADES• FRS & ESR mass measurements• RISING
RISING & MINIBALL
Summary
RISING fast beam campaign
- started data taking on time in 2003
First experiments
- Coulomb excitation of stable 84Kr (commissioning)
- Coulomb excitation of fragments: 56Cr,108Sn,112Sn
- Spectroscopy after secondary fragmentation of 55Ni
see talks: N. Hashimoto, M. Gorska, A. Bürger, M. Bentley
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