Sun Huibin

Nuclear data sheets for A = 52

The 2000 evaluation of A = 52 (2000Hu06) has been revised using experimental decay and reaction data. These data are summarized and presented, together with adopted level and transition properties.

Band crossings and signature splitting in 159Ho

High spin states in 159 Ho were populated in the reaction 152 Sm(11 B,4n) at 60 MeV. The rotational band based on the 7/2+ [404] Nilsson configuration has been established and the rotational bands based on the 7/2- [523], 1/2+ [411] and 1/2- [541] Nilsson configurations have been extended. The neutron band crossings of the various bands and the energy signature splitting of the 7/2- [523] bands are analysed in terms of the cranked shell model.

High-spin states in 159Lu

The high-spin states of 159Lu were studied through the reaction 144Sm(19F,4n) and the level scheme of 159Lu is reported for the first time. Higher values, of the first band-crossing frequency compared with those observed in heavier lutetium even-N isotopes, and signature splitting below the band crossing for the pi h11/2 negative-parity decay sequences in 159Lu, reported and briefly discussed.

On the newly proposed levels in152Gd and152Sm

It is shown that there is no evidence for the existence of levels at 1312.41, 1485.67 and 1698.34 keV in152Gd and at 1436.65 and 1681.56 keV in152Sm, which were recently claimed to be observed in the decay of152Eu(3−, 15 y).

Anomalous shift in crossing frequency for the proton 1/2[541] band in175Ta

High-spin states in175Ta have been populated in the160Gd (19F,4n)175Ta reaction with beams provided by the HI-13 tandem accelerator at the Institute of Atomic Energy in Beijing. A level scheme was constructed from γ-γ coincidence experiments. Seven decay sequences built on 5/2+[402], 1/2−[541], 7/2+[404] and 9/2− [514] proton Nilsson configuration have been extended to higher spin. An anomalously large delay of the neutron AB crossing built on the h9/2 proton Nilsson State 1/2−[541] is discussed.

Band-crossing frequencies of strongly populated bands in 174Ta

High spin states in 174Ta were populated in the 160Gd(19F,5n)174Ta reaction with a beam energy of 87MeV. A gamma - gamma coincidence experiment was performed using four HPGe-BGO Compton-suppressed spectrometers. The highest spins of the bands with configurations pi 5/2+(402)*v7/2+(633) and pi 1/2-(541)*v1/2-(521) could be pushed up to 21+ and 23+, and their first band-crossing frequencies were determined as 0.27+or-0.01 MeV and >0.38 MeV, respectively.

On some new levels in 182W

It is shown that reported coincidence relations which were used to establish the levels at 1624.07 and 1654.64 keV do not belong to the decay of 182Ta and thus these levels are not populated in the decay of 182Ta.

Levels in182W populated in the decay of182Ta

Theγ-rays emitted in theβ-decay of182Ta have been reinvestigated with improved statistics in attempting to clarify the reported new levels at 1460.41, 1592.98, 1620.36, 1712.29 and 1762.91 keV in182W observed in theβ-decay of182Ta. The present study demonstrated that the fifteen newγ-rays, which were used to support the existence of the five new levels, are not relevant to theγ-decay of182Ta. Therefore the five new levels are not populated in this decay. Additionally, theγ-ray with an energy of 1035.6 keV (02+→21+) deexciting theβ-band head in182W is observed for the first time in the present decay study and the previous tentative placement of the 351.0 keVγ-ray in the level scheme is confirmed by the present coincidence measurements.

Study of131Ba decay

Singles and coincidence spectra of gamma rays emitted in the decay of131Ba(11.8d) have been studied with improved statistics. The existence of the level at 1342.07 keV and gamma transitions at 82.58, 461.22, 562.87, 703.53, 1046.4, 1125.97, 1170.53, 1208.43 and 1342.02 keV have been confirmed. Thirteen previously unreported gamma rays at 390.1, 474.2, 506.1, 517.5, 533.7, 596.5, 657.6, 745.5, 757.0, 785.92, 840.9, 1037.0 and 1218.30 keV have been identified and seven new coincidence relations are reported. The level at 596.4 keV is proposed based on coincidence evidence and the level at 657.6 keV is tentatively proposed on the basis of energy differences. All the 62 gamma rays observed in this study have been placed into the decay scheme.