Inelastic Scattering of Neutrons and Surface Direct Processes

Abstract

ABS>In the case of inelastic scattering of neutrons in which the residual nucleus is left in a definite low-lying excited state, the surface direct processes through single particle excitation and through same sort of many particle excitations are formulated in a similar manner as in deuteronstripping reaction. The distorted wave method is employed and its validity for the mentioned processes is discussed in some detail. The cross sections obtained are compared with that of another surface direct process accompanied by collective excitation and with that of the process through compoumd nucleus formation. It is shown that for intermediate and heavy nuclei (i) the collective excitation is much larger tham the single particle excitation and (ii) the compound nucleus process is more important than the surface direct process in low energy region in which there are few open channels, while the latter is much larger than the former in higher energy region where mamy channels are open. (auth)