Exotic neutronrich nuclei

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Exotic neutron-rich nuclei

• Phil Walker
• University of Surrey

production reactions angular momentum
structure decay
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Chart of nuclides
I
K
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4-quasiparticle K-isomers in hafnium (Z72)
178Hf 188Hf
expt.
calc.
stability
Walker and Dracoulis, Hyp. Int. 135 (2001) 83
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190W116 anomaly
Podolyak et al., Phys Lett B491 (2000) 225
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prolate-oblate shape change
N 116
190Re115
192Re117
188Ta115
190Ta117
Total Routhian Surfaces Walker and Xu, Phys Rev
C74 (2006) 067303 Walker and Xu, Phys Lett B635
(2006) 286 Projected Shell Model Sun, Walker, Xu
and Liu, Phys Lett B659 (2008) 165 Stevenson
separable interaction Stevenson et al., Phys Rev
C72 (2005) 047303
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Projectile-fragmentation reactions at GSI
ion-by-ion mass and charge identification in the
FRS
Ge detectors
isomers and ground states reach the final focus
in 300 ns
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RISING at GSI 105 Ge crystals
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204Pt
Steer et al., submitted to PRL
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(No Transcript)
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Passive Stopper measurements g-rays from isomer
with T1/2 for 10 ns ? 1 ms. Active Stopper
measurements b -particles, i.c. electrons, T1/2
ms ?mins
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Active Stopper Spectroscopy of 205Au
Podolyak et al., submitted to PLB
T1/2 10.4 s
K-electrons
L-electrons
B(M4 11/2- ? 3/2) 0.95 W.u. Direct measure
of h11/2?d3/2 proton hole energy difference
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ß decay with active stopper N. Alkhomashi, P.H.
Regan et al., to be published
188Ta ? 188W
190Ta ? 190W
192Ta ? 192W
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Nuclei of focus in the A200 region for Active
Stopper measurements
203,205,(206)Au
213Bi
204Pt
198,202Ir
200Os
194,196,198Re
190,192Ta
Spokespersons P.H. Regan J.
Benlliure Analysis by N. Alkhmashi, N. Al-Dahan,
G. Farrelly, A. Morales et al.,
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Fragment Separator coupled toExperimental
Storage Ring at GSI
isomer ground state
Attallah et al., Nucl. Phys. A701 (2002) 561c
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potential for new isomers and ground-state
masses with storage rings at FAIR
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neutron radioactivity
unique to isomers?
high-spin isomer
n
threshold
A 1 n
gs
A
ß
NB mono-energetic neutrons 1MeV
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Coulomb and centrifugal barriers
A 100, l 5h
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the angular-momentum dimensionwith 238U
projectile fragmentation
Rexp 7 3
215Ra
214Ra
15 times more than expected
new data 148Tb 27 h
spin (h)
see also Pal and Palit Phys. Lett. B665 (2008)
164
Podolyak et al., Phys. Lett. B632 (2006) 203
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Exotic neutron-rich nuclei
focus on A 190 210 shell gaps r-process
nucleogenesis shape changes projectile-fragmentati
on reactions isomer spectroscopy gamma-ray
detection conversion-electron detection storage-ri
ng observation (neutron radioactivity) (high-spin
population)
thanks to Paddy Regan Zsolt Podolyak and many
others