Chuangye He

Signature splitting inversion and backbending in80Rb

High spin states of 80Rb are studied via the fusion-evaporation reactions 65Cu+19F, 66Zn+18O and 68Zn+16O with the beam energies of 75 MeV, 76 MeV and 80 MeV, respectively. Twenty-three new states with twenty-eight new \gamma transitions were added to the previously proposed level scheme, where the second negative-parity band is significantly pushed up to spins of 22^{-} and 15^{-} and two new sidebands are built on the known first negative-parity band. Two successive band crossings with frequencies 0.51 MeV and 0.61 MeV in the \alpha=0 branch as well as another one in the \alpha=1 branch of the second negative-parity band are observed for the first time. Signature inversions occur in the positive- and first negative-parity bands at the spins of 11\hbar and 15\hbar, respectively. The signature splitting is seen obviously in the second negative-parity band, but the signature inversion is not observed. It is also found that the structure of the two negative-parity bands is similar to that of its isotone ^{82}Y. Signature inversion in the positive-parity yrast band with configuration \pi g_{9/2} \otimes \nu g_{9/2} in this nucleus is discussed using the projected shell model (PSM).

High-Spin States and Level Structure in Stable Nucleus Strontium-84

High-spin states of 84Sr are populated through the reaction 70Zn (18O, 4n) 84Sr at the beam energy of 75 MeV. The measurements of excitation functions, γ-γ coincidences, directional correlations of oriented states (DCO) ratios and γ-transition intensities are performed using eight anticompton HPGe detectors and one planar HPGe detector. Based on the experimental results, we establish a new level scheme of 84Sr, in which 12 new states and nearly 30 new γ-transitions are identified in the present work. The positive-parity yrast band is extended to spin Iπ = 24+, while one negative-parity band is extended to spin Iπ = 19− and it is found that the even-spin and odd-spin members in high-spin states show the nature of signature staggering. The deformation of 84Sr is studied by calculating the total-Routhian-surfaces (TRS) of positive-parity yrast states in the cranked shell model formalism.

High-Spin States in141Pm

The high-spin states of 141Pm nucleus have been studied by using in-beam γ-ray spectroscopy technology through the126Te(19F, 4n) reaction at a beam energy of 90 MeV. The previous level scheme has been extended with spin up to 49/2 ℏ. Many new levels and transitions are identified. Five collective band structures are observed. Based on systematic comparison with the neighboring nuclei, two bands with strong ΔI = 1 M1 transitions inside the bands are proposed as the oblate bands with γ~−60°, and three bands with large signature splitting have been suggested as the oblate-triaxial deformation with γ~−90°. The characteristics for these bands have been discussed.

High Spin Structure in106Pd

The high spin states of Pd have been populated through the Mo(B, 1p4n)Pd reaction using a beam energy of 60 MeV provided by the Beijing HI-13 tandem accelerator at China Institute of Atomic Energy. By analyzing the γ-γ coincidence relation and DCO raios of transitions, 3 rotational bands with 13 new states and 22 new γ transitions belonging to Pd were constructed. Bands 2 and 3 with negative parity were supposed to build on the νh11/2g7/2 and νh11/2d5/2 configuration, respectively.The high spin states of 106Pd have been populated through the 100Mo(11B, 1p4n)106Pd reaction using a beam energy of 60 MeV provided by the Beijing HI-13 tandem accelerator at China Institute of Atomic Energy. By analyzing the γ-γ coincidence relation and DCO raios of transitions, 3 rotational bands with 13 new states and 22 new γ transitions belonging to 106Pd were constructed. Bands 2 and 3 with negative parity were supposed to build on the νh11/2g7/2 and νh11/2d5/2 configuration, respectively.

Yrast Band in122I and Band Termination

High spin states of the odd-odd nucleus 122I have been investigated via the fusion-evaporation reaction 116Cd(11B, 5n) at a beam energy of 68 MeV. The yrast band is extended up to Iπ = (29+). The band termination at Iπ = (22+) reported in previous studies is confirmed and interpreted as arising from a shape change from collective prolate to noncollective oblate according to Total-Routhian-Surface (TRS) calculations. In addition, the Iπ=(29+) state is assigned to the [πh11/2(πg7/2)2]23/2-⊗[(νh11/2)3(νd5/2)2]35/2− configuration corresponding to the full alignment of all valance nucleons outside the semi-closed shell.