Zhu Yong-tai

Fluctuation measurement of excitation function in the dissipative process of 19F + 51V reaction

Abstract Excitation functions of the projectile-like fragments in the dissipative reaction 19F + 51V have been measured from 102.25 MeV to 109.50 MeV in 250 keV steps. The corresponding energy coherence widths Γ were extracted by means of the energy autocorrelation function method. The dependence of Γ on the degree of freedom of neutron excess N Z and the dependence of the charge number Z on the angular momentum coherence width γ are presented and discussed.

Measurements of total reaction cross section for light nuclei and evidence for the anomalous nuclear structure in C-15

Measurements of the total reaction cross section for C12-16, N14-17 and O16-18 on carbon target at intermediate energies were performed on RIBLL of HIRFL. A larger enhancement of sigma(n) for C-15 was observed than that for its neighbors. The analysis of these data indicates possible existence of an anomalous nuclear structure in C-15. A new quantity was suggested as the criterion to distinguish anomalous structure nuclei from normal nuclei.

Total reaction cross section measurements at intermediate energy for the proton halo candidate Al-23 and its neighbours

Total reaction cross sections sigma (R) for some proton-rich isotones (N = 10) near Al-23 on a carbon target have been measured at intermediate energies in the experiment performed at the Radioactive Ion Beam Line of the Heavy Ion Research Facility in Lanzhou. The Z-dependence Of sigma (R) shows a remarkable enhancement for Al-23 relative to its neighbours. The difference factor d has been deduced from the measured sigma (R) by using the Glauber or Boltzmann-Uehling-Uhlenbeck models. From the above analysis, a possible one-proton halo structure is suggested for Al-23.

Experimental Probe to the Isospin-Dependent Properties of Hot Nuclei in Reactions 40Ar + 112,124Sn at 30 MeV/u

Protons are emitted in a greater quantity in a neutron-deficient system 40Ar+112Sn while triton emissions are greater in a neutron-rich system 40Ar+124Sn at an incident energy of 30 MeV/u. Similar to neutrons, proton emission provides a dominant contribution to neutralize the system N/Z in the decay process of the hot nuclei. The emission of hydrogen isotopes with high energies is much enhanced in the 112Sn system. The original temperature of the hot nuclei in the 40Ar+112Sn reaction is 5.8±0.3 MeV, about 0.7 MeV higher than 5.1±0.3 MeV as in the 40Ar+124Sn reaction.

STUDY OF THE NUCLEAR PHENOMENA IN THE LOW ENERGY (60-360 keV) PROTON BEAM IMPLANTATION ON METALS

A series of studies on the nuclear interaction and its effects in solids during proton implantation were performed in the energy region between 60 and 360keV. Some charged particle products were observed in the implantation experiments on metal samples such as deuterated titanium, titanium alloy, titanium foil on molybdenum substrate, molybdenum and stainless steel, etc.. The energies of the charged particle products are about 3.9, 5.6 and 8.4MeV, respectively. These particles were identified as alpha particles with both detector telescope and absorption measurements. These three kinds of alpha products were found from different proton sub-barrier reactions. The exciting curve of this reaction increases exponentially with the growth of proton energy in the energy region from 90 to 330keV. The radiation damages induced by the nuclear products in the sample have been studied with scanning electron microscopy technique. The possible surface damages induced by them were observed evidently. The origin of the nuclear reactions and their effect on implantation are discussed.

Isospin Effect of Fragmentation Reaction on the Isotopic Distribution Produced in Intermediate Energy Heavy Ion Collisions

Fragments produced in the reaction of 60MeV/n O-18 On Be have been measured experimentally. The isotopic distribution of fragmentation reaction is well reproduced by a modified statistical abrasion-ablation model. It is predicted that the isotopic distribution shifts toward the neutron rich side for neutron rich projectile, but this isospin effect decreases with the increase of the atomic number difference Z - Z(A) and disappears at last, where Z and Z(A) are atomic numbers of the isotopic distribution and the projectile respectively.

On isotope thermometers

The ratio of isotope yields integrated over a part of their energy spectrum is proposed to extract nuclear temperature of the excited emitter nucleus formed in heavy ion reactions. The nuclear temperature extracted from the isotope ratio is consistent with that extracted from the relative populations of the particle unstable states.

Semidecoupled band and shape driving effect of the pi 1/2(->)[541]orbital in Ta-170

High spin states in Ta-170 have been studied via Tb-159(O-16, 5n High spin states in Ta-170 have been studied via Tb-159(O-16, 5n

TARGET DEPENDENCE OF N/Z RATIO OF THE FRAGMENTS PRODUCED IN 30 MEV/U 40AR INDUCED REACTIONS

An inclusive measurement was performed for 30 MeV/u 40Ar+58,64Ni and 115In. By employing the degree of freedom of N/Z, the production mechanism of the high energy component of the intermediate mass fragments (IMFs: 3 ≤ Z ≤ 13) has been discussed. Special attention has been paid to the target dependence of N/Z ratio of the energetic fragments. These IMFs may be produced by a projectile fragmentation process with energy dissipation.

Signature Inversion of Yrast Band in Odd-Odd162Lu Nucleus

High spin states of the odd-odd 162Lu nucleus have been studied via 147 Sm(19F, 4nγ) reaction at 95 MeV beam energy. Level scheme for yrast band based on π[h11/2]ν[i13/2] quasiparticle configuration was established up to Iπ = (23-) for the first time. This band shows the signature inversion in energy before backbending generally appeared in this mass region. It is stressed that the signature splitting in 162 Lu is larger than that in 160 Tm nucleus.