Studies of neutron emission from relativistic nuclear interactions

Studies were carried out on the yields and spatial distributions of seconda ry neutrons produced in the relativistic nuclear interactions of 1.5 GeV to 14.4 GeV projectiles p, d and alpha-particles with targets Pb and U/Pb. CR -39 track detectors were used to measure the neutrons. It shows that: (1) S econdary neutrons are produced in the whole length of Pb or U targets havin g a thickness of 20cm. The neutron intensities produced by proton bombardme nts are reduced along the proton beam direction in the targets. The higher the energy of protons, the lower the reduction rate of the neutrons. The re duction rate of neutrons in U target is higher than in Pb target for the sa me energy of protons. (2) The radial intensities of neutrons decrease as th e distance increases from the target central line. (3) The neutron yield in U target by proton bombardments is similar to 55% higher than in Pb target . (4) The ratio of neutron yield by 14.4 GeV alpha to 7.3 GeV d bombardment in Pb target is 1.74 +/- 0.20.