1. Coulomb Excitation of Neutron-rich Xe-Isotopes @REX-ISOLDE
REX-ISOLDE ist eine Facility für radioaktive Strahlen am CERN
Thomas Behrens
Physik-Department E12
TU München

2. Gliederung
Physical motivation: Evolution of B(E2) values around N=82
Experimental setup and realisation at REX-ISOLDE (CERN) with MINIBALL
Preliminary results with 138,140Xe
Conclusion & Outlook

3. B(E2) values around N=82 122,124Cd 140Xe B(E2; 0+g2+) (e2b2)
preliminary results:
122Cd: 0.37(11)
124Cd: 0.32(10)
Motivation Te l l Cd l
140Xe
Setup
B(E2; 0+g2+) (e2b2) l l
Results
D. Radford et al.,
PRL 88, (2002)
INPC 2004, ENAM ‘04 l
Modifizierter Plot von Dave Radford
Momentaner Stand der bekannten B(E2) Werte l l
Outlook
Neutron Number
136Te

4. Coulomb Excitation • Beam energy below Coulomb barrier a“Safe Coulex”
• h = Z1Z2e2/ħn >> 1
• bproj ~ 0.06 c (aDoppler correction) b
Target Z
Projectile
Motivation
Setup i f
Results
Wir messen das Gamma aus der Abregung f -> i
Outlook

5. Experimental Setup Gamma- spectroscopy Particles Angles Energies Beam
MINIBALL
Particles
Angles
Energies
DSSSD
Univ. of Edinburgh
Beam
monitor
PPAC
TU Darmstadt
Beam
purity
Beam Dump
Detector
Motivation g
Setup
Beam
Target
Results
DE-E
Protons on converter target
Mk7 ion source
2.86 MeV/A from REX
no contamination
Outlook

6. CD energy vs angle
Motivation
96Mo
Setup
140Xe
Results
Outlook

7. IS411 – 140Xe on 96Mo Eg : Eg>0 & ECD>0 Eg [keV] Motivation
Setup
140Ba
140Xe
140Cs
Results
Outlook
Eg [keV]

8. IS411 – 138Xe peak
Motivation
138Xe
Setup
96Mo
Results
Outlook

9. IS411 – 96Mo peak
Motivation
96Mo
138Xe
Setup
Results
Outlook

10. IS411 – 140Xe peak
Motivation
140Xe
Setup
Results
96Mo
Outlook

11. IS411 – 96Mo peak
Motivation
140Xe
Setup
96Mo
Results
Outlook

12. IS411 – Intensity on CD
Motivation
Setup
Results
Outlook

13. Conclusions & Outlook successful measurement of 138,140,142Xe
Motivation
successful measurement of 138,140,142Xe
with good statistics
open tasks:
- analysis of 142Xe
detector positions
Setup
planned runs: 126Cd, 144Xe (approved)
Results
proposed: development of BaF+ beams for heavy Ba isotopes
Outlook

14. Future Experiments Ba isotopes Mass Number Motivation 148,150Ba Setup
Results
dashed line: theory
solid line: Grodzins rule
Outlook
Mass Number

15. Helping hands and heads...
T. Behrens1, V. Bildstein1, R. Gernhäuser1, Th. Kröll1,
R. Krücken1, P. Maierbeck1, D. Habs2, R. Lutter2,
T. Morgan2, P. Thirolf2, O. Niedermaier3,
H. Scheit3, D. Schwalm3, N. Warr4, D. Weisshaar4,
O. Ivanov5, I. Stefanescu5, P. van Duppen5, J. van de Walle5,
P.E. Kent6, A. Ekström7, J. Cederkall8, P. Delahaye8,
L. Fraile8, U. Köster8, T. Sieber8, F. Wenander8,
P. Butler9, A. Hurst9, T. Davinson10, J. Iwanicki11,
G. Georgiev12, A. Scherillo13 and the REX-MINIBALL collaboration
1TU München, 2LMU München, 3MPI-K Heidelberg,
4Universität zu Köln, 5KU Leuven, 6University of York,
7Lund University,8CERN, 9University of Liverpool,
10University of Edinburgh, 11Warsaw University, 12IPN Orsay,
13ILL Grenoble
Thank you for your attention!

16. Experimental Setup Gamma spectroscopy Particles Angles Energies Beam
MINIBALL
Particles
Angles
Energies
DSSSD
Beam
monitor
PPAC
Beam
purity
Beam Dump
Detector g g
Beam
Neue IC wird an unserem Institut entwickelt.
DE-E
IC - Si
Telescope
Thomas Behrens

17. REX-ISOLDE @ CERN Targets MINIBALL NEW: 3 MeV/A ISOLDE Thomas Behrens5
10 m
Thomas Behrens