Future prospects for high resolution gammaray spectroscopy at GANIL with Doppler shift techniques

1
Future prospects for high resolution gamma-ray
spectroscopy at GANIL with Doppler shift
techniques
C. Fransen, A. Dewald et al., University of
Cologne

• Measurement of lifetimes of non-Yrast states
  with RDDS and DSAM
• fundamental information about nuclear
  structure
• ? Cologne Plunger Device / new designs for RIBs
• Plunger gamma-arrays (EXOGAM, JUROGAM, )
• ancillary detectors particle detectors,
  recoil spectrometers
• (VAMOS, RITU, )
• ? Experimental means Coulex or
  fusion-evaporation reactions with
• radioactive beams in inverse kinematics
• ? Applications of these successful techniques
  with RIB at SPIRAL2

2
(No Transcript)
3
Inverse Kinematics Coulomb Excitation
degrader foil
coulex target
particle detector
beam
v1
v2
coulex on degrader
coulex on target
gate on target recoils
v2
v1
4
Accepted proposal for an experiment at
Jyväskylä Inverse coulex of 128/130-Xe_at_
525MeV Spokespersons S. Harissopulos,
A.D. Cologne plunger particle detectors
JUROGAM
D. Rudolph, Lund
5
N. Pietralla, priv. comm.
6
Plunger RITU at Jyväskylä
PSSD
He at 1-2 mbar
JUROGAM Ge array 4 ?-eff.
Q
1m
Q
D
Q
RITU separator 30 recoil eff.
beam
target
C- foil
7
Plunger VAMOS at GANIL
Detection
VAMOS
EXOGAM Ge array
Q
Q
D
beam
Wien filter
target
EXOGAM
VAMOS
8
(No Transcript)
9
186Pb
exp.
cal.
conf. mix of mean
field states (Skyrme intera.SLy6)

M. Bender et al. PRC 69 (2004), 064303
privat com.
16
E/MeV
E/MeV

8

(14)
14
242 WU
(12)
3
3
12
6
2
(10)
ß 0.32
ß 0.30(2)
205 WU
(8)
10
8
2
2
4
(6)
8
543 WU
6
152 WU
(4)
246(42) WU
6
2
480 WU
56 WU
438(98)WU
(2)
1
4
1
4
0
2
480(90)WU
398 WU
2
9.4 WU
0
0
0
1.6 WU
5.5 (15)WU
0
0
0
0
10
K. Starosta et al. RDDS Test _at_ MSU , NSCL, 2004
11
(No Transcript)
12
RISING lifetime experiment GSI using secondary
fragmentation spokes person J. Gerl, GSI
2 mm
2 mm
Target stack Fe 3 x 0.3 g/cm2
New 36K transition
13
RIB at SPIRAL2
Particles / s
14
Mixed-symmetry states
15
Mixed-symmetry states
16
Conclusion

• Lifetime measurements with Doppler-shift
  techniques are powerful tools for nuclear
  structure investigations.
• Application of these techniques at high current
  RIB facilities like SPIRAL2 in Coulex, fusion
  reactions, and direct reactions will be very
  capable.
• Extend the knowledge on nuclear properties,
  especially collective non-yrast states, e.g.,
  collective pn non-symmetric (mixed-symmetry)
  states or of nuclei at critical points of shape
  phase transitions.

17
Symmetries at critical points of nuclear shape
phase transitions
E(5) vibrator / U(5) gamma-unstable rotor /
O(6) F. Iachello, Phys. Rev. Lett. 85, 2000
X(5) vibrator / U(5) symmetric rotor/ SU(3)
F. Iachello, Phys. Rev. Lett. 87, 2001 Y(5)
symmetric rotor / SU(3) - triaxial rotor /
SU(3) F. Iachello, Phys. Rev. Lett. 91,
2003 Z(5) prolate to oblate deformation D.
Bonatsos et.al., Phys. Lett. B 588, 2004
J.Jolie et al. Phys.Rev.Lett. 87, 2001
Qt - gsb
E(4)/E(2)2.91 2.80
E(02)/E(21)5.67
X(5) like nuclei 152Sm, R.F. Casten et al.
PRL 87, 2001
150Nd, R. Krücken et al. PRL 88, 2002
18
Regions for X(5) nuclei
A124
A120
A180
A150
A104
Regions, where X(5) nuclei are expected
19
Plunger RITU at Jyväskylä
PSSD
He at 1-2 mbar
JUROGAM Ge array 4 ?-eff.
Q
1m
Q
D
Q
RITU separator 30 recoil eff.
beam
target
C- foil