Study of neutron production processes via (d, n) reactions with time-of-flight method

 The (d,n) reactions for C--Co targets have been systematically studied at 55 MeV. At a forward angle of 9.5 degrees, the continuum bumps dominate the cross sections. The peak cross sections have been well described by the A^2/3 dependence on the target mass number A.This A-dependence means that the breakup cross sections are proportional to the geometrical cross sections of the targets. The peak energy is about half of the incident deuteron energy, and decreases with increasing A.The peak width in FWHM also decreases gradually with increasing A.These features can be reasonably reproduced qualitatively by considering the Coulomb force effects. However, significant discrepancy was also observed especially for C and Al targets, suggesting the resonance contributions from 13N and 28Si.Thus we have obtained new data at 0 degrees where the non-resonant proton-stripping process becomes more dominant, and thus the resonance effects would be small. Furthermore, thick-target neutron yields (TTNYs) have been also measured. In a simple reaction model, the TTNYs are expected to be independent of A. However, complicated reaction processes such as the secondary reaction would cause the A-dependence. We will present these new data and compare them with recent theoretical calculations.