16+ spin-gap isomer in 96Cd Nara Singh, B S; Liu, Z; Wadsworth, R ...
Physical review letters,
2011-Oct-21, Letnik:
107, Številka:
17
Journal Article
Recenzirano
Odprti dostop
A β-decaying high-spin isomer in (96)Cd, with a half-life T(1/2)=0.29(-0.10)(+0.11) s, has been established in a stopped beam rare isotope spectroscopic investigations at GSI (RISING) experiment. The ...nuclei were produced using the fragmentation of a primary beam of (124)Xe on a (9)Be target. From the half-life and the observed γ decays in the daughter nucleus, (96)Ag, we conclude that the β-decaying state is the long predicted 16(+) "spin-gap" isomer. Shell-model calculations, using the Gross-Frenkel interaction and the πν(p(1/2),g(9/2)) model space, show that the isoscalar component of the neutron-proton interaction is essential to explain the origin of the isomer. Core excitations across the N=Z=50 gaps and the Gamow-Teller strength, B(GT) distributions have been studied via large-scale shell-model calculations using the πν(g,d,s) model space to compare with the experimental B(GT) value obtained from the half-life of the isomer.
Detailed spectroscopy employing the β+/EC decay of 110,112In and the β− decay of 112Ag has been used to study the excited states of 110,112Cd. Low-energy decay branches from highly excited states ...have been observed and, combined with level lifetimes from the (n,n'γ) reaction, permit B(E2) values to be determined thus revealing rotational-like bands built on excited 0+ states and γ bands built on the ground and the shape-coexisting intruder states. The excitation energies of the04+states appear incompatible with that expected for a pure π(4p6h) configuration. The experimental results for the 0+ excited states are compared with beyond-mean-field calculations that suggest they possess different shapes, including prolate, oblate, and triaxial.
The lifetime of the \({4}_{1}^{+}\) state in 208Po has been measured using γ − γ fast-timing technique with LaBr3(Ce) Detectors. The experiment was performed at the FN Tandem facility at the ...University of Cologne. The preliminary results are discussed in the scope of the systematic behavior of the transition strengths between yrast states in polonium isotopes.
Lifetime measurement of excited states in 46Ti Goldkuhle, A.; Fransen, C.; Dewald, A. ...
The European physical journal. A, Hadrons and nuclei,
2019/4, Letnik:
55, Številka:
4
Journal Article
Recenzirano
.
The level lifetimes of the yrast 2
1
+
, 4
1
+
and 6
1
+
states and an upper limit of the lifetime of the 8
1
+
state in
46
Ti have been measured with high accuracy exploiting the recoil distance ...Doppler-shift method (RDDS) and using
γ
γ
coincidences. The nuclei were populated by the fusion evaporation reaction
40
Ca(
9
Be, 2p1n)
46
Ti at a beam energy of
E
=
33
MeV at the FN tandem accelerator of the University of Cologne, Germany. Lifetimes were extracted using the established differential decay curve method (DDCM).
A first performance test of the Coulomb excitation multipolarimetry (
Coulex-multipolarimetry
) method is presented. It is based on a
85
Br
π
p
3
/
2
→
π
p
1
/
2
spin-flip experiment performed as ...part of the PreSPEC-AGATA campaign at the GSI Helmholtzzentrum für Schwerionenforschung (GSI). Via determination of background levels around the expected
85
Br
excitations as well as measured
197
Au
excitations, an upper limit for the
M
1 transition strength of the
1
/
2
1
-
→
3
/
2
g.s.
-
transition in
85
Br
and a lower beam time limit for upcoming experimental campaigns utilizing
Coulex-multipolarimetry
have been inferred. The impact of the use of AGATA in its anticipated
1
π
configuration on these estimates is deduced via
Geant4
simulations.
We examine a quantum phase transition in gamma-soft nuclei, where the O(6) limit is simultaneously a dynamical symmetry of the U(6) group of the interacting boson model and a critical point of a ...prolate-oblate phase transition. This is the only example of phase transitional behavior that can be described analytically for a finite s,d boson system.
Isomeric states in isotopes in the vicinity of doubly-magic 208Pb were populated following reactions of a relativistic 208Pb primary beam impinging on a 9Be fragmentation target. Secondary beams of ...198,200,202,206Pb and 206Hg were isotopically separated and implanted in a passive stopper positioned in the focal plane of the GSI Fragment Separator. Delayed γ rays were detected with the Advanced Gamma Tracking Array (AGATA). Decay schemes were re-evaluated and interpreted with shell-model calculations. The momentum-dependent population of isomeric states in the two-nucleon hole nuclei 206Pb/206Hg was found to differ from the population of multi neutron-hole isomeric states in 198,200,202Pb.
Triple point of nuclear deformations Jolie, J; Cejnar, P; Casten, R F ...
Physical review letters,
10/2002, Letnik:
89, Številka:
18
Journal Article
Recenzirano
We show that the second-order phase transition between spherical and deformed shapes of atomic nuclei is an isolated point following from the Landau theory of phase transitions. This point can occur ...only at the junction of two or more first-order phase transitions which explains why it is associated with one special type of structure and requires the recently proposed first-order phase transition between prolate and oblate nuclear shapes. Finally, we suggest the first empirical example of a nucleus located at the isolated triple-point.
In this study we present the preliminary results about the lifetimes of the 2 2 + , 4 1 + states of 208Po and the upper limit of the lifetime of the 2 1 + state. For measuring the lifetimes of the 2 ...1 + and 4 1 + states the Recoil Distance Doppler Shift (RDDS) method and for the lifetime of the 2 2 + state the Doppler Shift Attenuation method (DSAM) were used. The resulting absolute transition strength B ( M 1 ; 2 2 + → 2 1 + ) ≥ 0.122 ( 20 ) μ N 2 reveals the predominant isovector nature of the 2 2 + state of 208Po.
Collective properties of the low-lying levels in the odd-A 67-73Cu were investigated by Coulomb excitation with radioactive beams. The beams were produced at ISOLDE and postaccelerated by REX-ISOLDE ...up to 2.99 MeV/u. In 67,69Cu, low-lying 1/2(-), 5/2(-), and 7/2(-) states were populated. In 71,73Cu, besides the known transitions deexciting the single-particle-like 5/2(-) and core-coupled 7/2(-) levels, gamma rays of 454 and 135 keV, respectively, were observed for the first time. Based on a reanalysis of beta-decay work and comparison with the systematics, a spin 1/2(-) is suggested for these excited states. Three B(E2) values were determined in each of the four isotopes. The results indicate a significant change in the structure of the odd-A Cu isotopes beyond N=40 where single-particle-like and collective levels are suggested to coexist at very low excitation energies.
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