| 1. |
- Cederwall, Bo, et al.
(författare)
-
Evidence for enhanced collectivity in Te-I-Xe nuclei near the N=Z=50 double shell closure
- 2007
-
Ingår i: PROTON EMITTING NUCLEI AND RELATED TOPICS. - MELVILLE, USA : AMER INST PHYSICS. - 9780735404755 ; , s. 156-162
-
Konferensbidrag (refereegranskat)abstract
- Gamma-ray transitions have been identified for the first time in the extremely neutron-deficient T-z = 1 nuclide Xe-110 and the energies of the three lowest excited states in the ground-state band have been deduced. A level scheme has also been constructed for the proton-unbound, T-z = 3/2 nuclide I-109, exhibiting band structures built on g(7/2) and h(11/2) states in a weakly deformed, triaxial nucleus. In addition, a third band is proposed to be bui It oil a g(7/2) orbital coupled to an octupole-vibrational phonon of the Te-108 core. The results were obtained in a recoil-decay tagging experiment using the Ni-58(Fe-54,2n/p2n) reaction at a beam energy of 195 MeV. The experiment was performed using the highly efficient JUROGAM y-ray spectrometer in conjunction with the RITU gas-filled recoil separator and the GREAT focal -plane spectrometer. The results on Xe-110 establish a breaking of the normal trend of increasing first excited 2(+) and 4(+) level energies as a function of decreasing neutron number as the N = 50 major shell gap is approached for the neutron-deficient Xe isotopes. This unusual feature is suggested to be an effect of enhanced collectivity, possibly arising from isoscalar n-p interactions becoming increasingly important close to the N = Z line. Features in the low-lying levels of Te-106 and I-109, showing similar trends, are also discussed.
|
|
| 2. |
- Delion, D. S., et al.
(författare)
-
Decay rules in proton emission
- 2007
-
Ingår i: Proton Emitting Nuclei and Related Topics. - : American Institute of Physics (AIP). - 9780735404755 ; , s. 47-52
-
Konferensbidrag (refereegranskat)abstract
- We give a simple relation, connecting the logarithm of the half-life, corrected by the centrifugal barrier, with the Coulomb parameter in proton decay processes. The reduced experimental data lie on two straight lines as a result of a sudden change in the nuclear shape, marking two regions of deformation, divided by the charge number Z = 68. This feature provides a powerful tool to assign experimentally quantum numbers in proton emitters.
|
|
| 3. |
- Joss, D. T., et al.
(författare)
-
Discovery of the proton emitting nucleus 159Re
- 2007
-
Ingår i: Proton Emitting Nuclei and Related Topics. - : American Institute of Physics (AIP). - 9780735404755 ; , s. 28-33
-
Konferensbidrag (refereegranskat)abstract
- The observation of the new nuclide 159Re provides important insights into the evolution of single-particle structure in heavy nuclei beyond the proton drip line. The nuclide 159Re was synthesised in the reaction 106Cd(58Ni, p4n) and identified via its proton radioactivity using the RITU gas-filled separator and the GREAT focal-plane spectrometer. Comparisons of the measured proton energy (Ep = 1805±20 keV) and decay half-life (t1/2 = 21±4 μs) with values calculated using the WKB method indicate that the proton is emitted from an h11/2 state. The implications of these results for future experimental investigations into even more proton unbound Re isotopes using in-flight separation techniques are considered.
|
|
| 4. |
- Page, R. D., et al.
(författare)
-
Probing single-particle structures beyond the proton drip line
- 2007
-
Ingår i: Proton Emitting Nuclei and Related Topics. - : American Institute of Physics (AIP). - 9780735404755 ; , s. 137-142
-
Konferensbidrag (refereegranskat)abstract
- Single-particle energies have been investigated in the closed neutron shell proton emitter 155Ta. The 155Ta nuclei were populated through the α decay of 159Re, which has been observed for the first time. The 159Re nuclei were produced in reactions of 300 MeV 58Ni ions with an isotopically enriched 106Cd target, separated in-flight using the RITU separator and implanted into the GREAT spectrometer. The 159Re α decay emanates from the proton-emitting πh11/2 state and populates a state in 155Ta which decays by the emission of a proton from a πh 11/2 orbital. The results fit in with the systematics of proton and α-particle separation energies in the region, but disagree with the previously reported decay properties of 155Ta.
|
|
| 5. |
|
|
