EFFECT OF SLOW NEUTRON IRRADIATION ON SUPERCONDUCTIVE FILM

Irradiation effect by slow neutrons at a low fluence of about 108n/cm2 on YBCO and GB-CO films was reported in this paper. It was experimentally shown that appropriate slow meutron irradiation would increase the critical current densities Jcm at higher temperature (78K) and have almost no effect on Jcm at lower temperature (57K). Peak effect deduced by appropriate irradiation was observed in the field dependence of Jcm and volume flux pinning force density Fp at 78K. Based on mechanisms of slow-neutron irradiation , some discussions were made.     

DETERMINATION OF THE NEUTRON ATTENUATION LENGTH λ IN CONCRETE SHIELDING

A precise attenuation length λ is greatly important in calculation of shielding, sincethis parameter influences the radiation field transmitted by an accelerator shield. Thecost may be considerablely reduced, if the reasenable paramaters are accepted. Nuclude spectral analysis of concrete samples taken from the shielding wall near bythe target of high energy accelerator have been made. The attenuation length λ isdetermined and compared with results from other labordtories.     

THE PROTON AND NEUTRON SUBSHELLS AND THE INTERPLAY BETWEEN THEM (Ⅱ) RARE EARTH REGION

Based on the experimental data of even-even nuclei in rare earth region, a further study on the interplay between subshells of two kinds of nucleons has been carried out. Emphasis is placed on the characteristice and N, I dependence of Z=64 subshell. Theoretical explanation is given in terms of the Nilsson diagram and a simplified calculation of n-p interactions.     

COULD 7Be BE DESTROYED BY NEUTRON ABSORPTION IN THE SUN? -A NOTE ON THE SOLAR NEUTRINO PUZZLE

A comparison is made between the rate of the ⁷Be(p,y) ⁸B reaction and the rate of the neutron absorption reaction ⁷Be(n,p) ⁷Li which might have been important in. destroying ⁷Be in the solar interior.     

ELASTIC SCATTERING OF K± MESONS BY 40—48Ca AND THE ANALYSIS OF NEUTRON DISTRIBUTIONS

The differential cross sections of the elastic scattering of K^±on ^40—48Ca are calculated in the framework of eikonal approximation. The theoretical values obtained by using different parameters are compared. Through adjusting the parameters of the neutron distribution, the improvement of the coincidence between the theoretical values and the experimental data is arrived. The result shows that the r.m.s radius of the neutron distribution of ⁴⁰Ca is smaller than that of the proton. (about 0.15fm smaller) and the surface thickness of the neutron distribution of ⁴⁰Ca is thinner than that of proton. This is consistent with the results of computation made by H.F. method and agrees with the analysis of elastic scaatering of protons in the mediate energy on ⁴⁰Ca by other authors.     

FORMATION AND EMISSION OF LIGHT PARTICLES IN FAST NEUTRON INDUCED REACTION——A UNIFIED COMPOUND PRE-EQUILIBRIUM MODEL(2)

For fast neutron-induced reactions for structural"materials by using the unified compound pre-equilibrium model, the light composite particles emissions have to be oaken into account properly. The mechanism of cluster fororation and emission was investigated. Estimated results with considering the secondary emission process were compared with experimental data.