Recent progress of neutronics experiments

The reflected neutrons from pure cement bombarded by D-T and D-D fusion neutrons, and 252Cf spontaneous fission neutrons were studied using the methods of nuclear activation and uranium fission. The absolute activation reaction rates of six kinds of foils with high threshold energy, and the absolute fission reaction rates of 235U (wrapped by cadmium) and 238U nuclides, were measured. The angular neutron spectra from polyethylene slabs with thicknesses of 4.5, 9, 18, and 27cm were measured using the method of proton recoil. The neutron energy spectra above 1MeV were also measured this way in the multi-shell assembly which was made of beryllium,stainless steel and polyethylene.The measuring positions were 0,9.7,12.8 and 17.3cm away fron the center of the assembly. By the relative measurement method with an Al sample, the (n, 2n) reaction cross sections of Ru and Y nuclides were obtained. The experimental uncertainties in all the results were analyzed.