| 1. |
- Kumar, R., et al.
(författare)
-
ENHANCED 0(g.s.)(+) -> 2(1)(+) E2 TRANSITION STRENGTH IN Sn-112,Sn-114
- 2011
-
Ingår i: Acta Physica Polonica B. - 0587-4254. ; 42:3-4, s. 813-816
-
Konferensbidrag (refereegranskat)abstract
- The poorly known B(E2; 0(+) -> 2(+)) values of Sn-112 and Sn-114 have been measured to high precision. Two Coulomb excitation experiments were performed to determine the reduced transition probabilities relative to Sn-116 in order to minimize the systematic errors. The obtained B(E2 up arrow) values of 0.242(8) e(2)b(2) for Sn-112 and 0.232(8) e(2)b(2) for Sn-114 confirm the tendency of large B(E2 up arrow) values for the lighter tin isotopes below the midshell Sn-116 that has been observed recently in various radioactive ion beam experiments.
|
|
| 2. |
- Doornenbal, P., et al.
(författare)
-
RISING: Gamma‐ray Spectroscopy with Radioactive Beams at GSI
- 2007
-
Ingår i: AIP Conference Proceedings. - : AIP. - 0094-243X. - 9780735413283 ; 891, s. 99-107
-
Konferensbidrag (refereegranskat)abstract
- The Rare Isotope Spectroscopic INvestigation at GSI (RISING) project is a major pan‐European collaboration. Its physics aims are the studies of exotic nuclear matter with abnormal proton‐to‐neutron ratios compared with naturally occurring isotopes. RISING combines the FRagment Separator (FRS) which allows relativistic energies and projectile fragmentation reactions with EUROBALL Ge Cluster detectors for γ spectroscopic research. The RISING setup can be used in two different configurations. Either the nuclei of interest are investigated after being stopped or the heavy ions hit a secondary target at relativistic energies and the thereby occurring excitations are studied. For the latter case, MINIBALL Ge detectors and the HECTOR array are used in addition. Example achievements of the Fast Beam setup are presented and compared to various shell model calculations, while for the Stopped Beam setup initial results are shown.
|
|
| 3. |
- Naqvi, F., et al.
(författare)
-
Isomer spectroscopy of (127)Cd
- 2010
-
Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 82:3, s. 034323-
-
Tidskriftsartikel (refereegranskat)abstract
- The spin and configurational structure of excited states of (127)Cd, the two-proton and three-neutron hole neighbor of (132)Sn, has been studied. An isomeric state with a half-life of 17.5(3) mu s was populated in the fragmentation of a (136)Xe beam on a (9)Be target at a beam energy of 750 MeV/u. Time distributions of the delayed gamma transitions and gamma gamma coincidence relations were exploited to construct a decay scheme. The observed yrast (19/2)(+) isomer is proposed to have dominant configurations of nu(h(11/2)(-3))pi(g(9/2)(-1), p(1/2)(-1)), nu(h(11/2)(-2)d(3/2)(-1))pi(g(9/2)(-2)), and nu(h(11/2)(-2), s(1/2)(-1))pi(g(9/2)(-2)) and to decay by two competing stretched M2 and E3 transitions. Experimental results are compared with the isotone (129)Sn. The new information provides input for the proton-neutron interaction and the evolution of neutron hole energies in nuclei around the doubly magic (132)Sn core.
|
|
| 4. |
- Caceres, L. S., et al.
(författare)
-
Identification of Excited States in the N = Z Nucleus 82Nb
- 2007
-
Ingår i: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 38:4, s. 1271-1275
-
Tidskriftsartikel (refereegranskat)abstract
- Information on the first excited states in the N = Z = 41 nucleus Nb-82 sheds light on the competition of isospin T = 0 and T = 1 states in the A similar to 80 region. The measurement was performed at the GSI laboratory using fragmentation of a Ag-107 primary beam at 750 MeV/u on a 4 g/cm(2) Be-9 target. The fragments were separated and identified unambiguously in the FRagment Separator. Three excited states were observed and the half-life estimate for the isomeric state was extracted. A tentative spin assignment based on the isobaric analogue states systematics in the T-z = 1 nucleus Zr-82, and transition probabilities indicate T = 1 character of the first two excited states, and T = 0 for the isomeric state.
|
|
| 5. |
- Caceres, L., et al.
(författare)
-
Spherical proton-neutron structure of isomeric states in Cd-128
- 2009
-
Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 79:1, s. 011301-
-
Tidskriftsartikel (refereegranskat)abstract
- The gamma-ray decay of isomeric states in the even-even nucleus Cd-128 has been observed. The nucleus of interest was produced both by the fragmentation of Xe-136 and the fission of U-238 primary beams. The level scheme was unambiguously constructed based on.. coincidence relations in conjunction with detailed lifetime analysis employed for the first time on this nucleus. Large-scale shell-model calculations, without consideration of excitations across the N = 82 shell closure, were performed and provide a consistent description of the experimental level scheme. The structure of the isomeric states and their decays exhibit coexistence of proton, neutron, and strongly mixed configurations due to p. interaction in overlapping orbitals for both proton and neutron holes.
|
|
| 6. |
- De Angelis, G., et al.
(författare)
-
Collective Excitations in the Vicinity of N=Z
- 1999. - 1 SUPPL. 1
-
Ingår i: Proceedings INPC 1998. - 0375-9474. ; 654, s. 659-662
-
Konferensbidrag (refereegranskat)abstract
- In our contribution to the INPC98 conference we reported on the experimental investigation of high spin collective states in medium and heavy mass N≈Z nuclei at LNL. The main purpose is to set light on the role of the proton-neutron interaction in the collective behavior of the nucleus. In medium mass N=Z nuclei, in contrast with the stable nuclei, valence protons and neutrons occupy the same orbitals and one may expect a reinforcement of neutron-proton T=0 (np) pairing correlations[1]. In this interesting subject, the medium mass N=Z=36 72Kr has been studied and completely reported in [2]. In this proceedings we will concentrate in unpublished results concerning the onset of collectivity on nearly spherical nuclei in the 100Sn region. In nuclei with Z=50 and Z=49 dipole bands have been found indicating the presence of "Magnetic Rotation" [3].
|
|
| 7. |
- Doornenbal, P., et al.
(författare)
-
Enhanced strength of the 2(1)(+) -> 0(g.s.)(+) transition in Sn-114 studied via Coulomb excitation in inverse kinematics
- 2008
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 78:3
-
Tidskriftsartikel (refereegranskat)abstract
- The 2(1)(+) states of Sn-114,Sn-116 were excited in two consecutive experiments by means of Coulomb excitation in inverse kinematics on a Ni-58 target. A precise determination of the reduced transition probability B(E2; 0(g.s.)(+) -> 2(1)(+)) of Sn-114 relative to the well-known 2(1)(+) excitation strength in Sn-116 was achieved by comparing the relative projectile to target 2(1)(+) -> 0(g.s.)(+) decay intensities. The obtained B(E2 up arrow) value of 0.232(8)e(2)b(2) for Sn-114 confirms the tendency of large B(E2 up arrow) values for the light tin isotopes below the midshell Sn-116 that has been observed recently in various radioactive ion beam experiments. The result establishes most clearly the discrepancy between the current B(E2 up arrow) value predictions from large-scale shell-model calculations and the experimental deviation, which commences already for the stable Sn-114 isotope.
|
|
| 8. |
- Gadea, A., et al.
(författare)
-
Observation of Ni-54 : Cross-conjugate symmetry in f(7/2) mirror energy differences
- 2006
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 97:15, s. 152501-
-
Tidskriftsartikel (refereegranskat)abstract
- Gamma decays from excited states up to J(pi)=6(+) in the N=Z-2 nucleus Ni-54 have been identified for the first time. Level energies are compared with those of the isobars Co-54 and Fe-54 and of the cross-conjugate nuclei of mass A=42. The good but puzzling f(7/2) cross-conjugate symmetry in mirror and triplet energy differences is analyzed. Shell model calculations reproduce the new data but the necessary nuclear charge-dependent phenomenology is not fully explained by modern nucleon-nucleon potentials.
|
|
| 9. |
- Garnsworthy, A. B., et al.
(författare)
-
Isomeric States in Neutron-deficient A~80-90 Nuclei Populated in the Fragmentation of 107Ag
- 2009
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:6
-
Tidskriftsartikel (refereegranskat)abstract
- The relativistic projectile fragmentation of a 750 MeV per nucleon beam of Ag-107 was used to populate isomeric states in neutron-deficient nuclei around A=80-90. Reaction products were separated and unambiguously identified using the GSI FRagment Separator (FRS) and its ancillary detectors. At the final focal plane, the fragments were slowed from relativistic energies by means of an aluminium degrader and implanted in a passive stopper in the center of the high-efficiency, high-granularity Stopped Rare Isotope Spectroscopic INvestigation at GSI (RISING) germanium array. This allowed the identification of excited states in the N=Z nuclei Tc-86(43) and, for the first time, Nb-82(41). Isomeric states have also been identified for the first time in Tc-87,Tc-88, and a previously unreported isomer was observed in Nb-84. Experimental results are presented along with a discussion on the structure of these nuclei based on interpretations provided by several theoretical models.
|
|
| 10. |
- Garnsworthy, A. B., et al.
(författare)
-
Isomeric States in the Light Tc Isotopes
- 2007
-
Ingår i: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 38:4, s. 1265-1269
-
Tidskriftsartikel (refereegranskat)abstract
- Preliminary results from the first experiment of the Stopped Beam RISING campaign are presented. The relativistic projectile fragmentation of a 750 MeV/u beam of Ag-107 populated isomeric states in very neutron deficient nuclei at the proton dripline around mass 80-90. Nuclei were unambiguously identified using the FRagment Separator (FRS) and its ancillary detectors located at GSI. The ions produced were slowed down from relativistic energies by means of an Al degrader and implanted in the centre of the high-efficiency Stopped RISING array. This allowed the identification of new excited states in the N = Z = 43 nucleus, Tc-86, populated following the de-excitation of a microsecond isomer. Preliminary results of this analysis, as well as previously unobserved isomeric states in Tc-87,Tc-88. are reported.
|
|
