Gamma-ray spectra excited by the inelastic scattering of fast neutrons by Mg, Al, Fe, Cu, Sn, and Sb

Abstract

The study of the inelastic scattering of fast neutrons is of considerable theoretical and practical importance. From the theoretical point of view such studies provide information about the levels of stable nuclei. The practical value of these studies is due to the importance of inelastically scattered neutrons in the operation of fast neutron reactors. A knowledge of the spectra of the inelastically scattered neutrons is essential to the provision of a sound theory of fast reactors. ^(1,2) In order to provide this information, the last 5–7 years has seen a considerable amount of work devoted to the development of fast neutron spectrometry and to the spectroscopy of the gamma-rays accompanying inelastic neutron scattering.

In this paper, we report measurements of the spectra of gamma-rays excited by the inelastic scattering of 2·8 MeV neutrons by Mg, Al, Fe, Cu, Sn, and Sb. A NaI(Tl) scintillation spectrometer was used in this work in conjunction with a photomultiplier, type FEU-1B, and a 50 channel pulse height analyser incorporating a magnetic drum memory device. For ⁶⁰Co gamma-rays, the resolution of the spectrometer was 6·5–7 per cent. Gamma-rays having the following energies (MeV) were observed: Mg 0·97; 1·41; 1·92; 2·3. Al 0·84; 1·00; 1·80; 2·16. Fe 0·84; 1·25; 1·46; 1·70. Cu 0·63; 0·78; 0·96; 1·12; 1·38; 1·46; 1·72; 2·03. Sn 0·84; 1·16; 1·50; 1·80; 2·16. Sb 1·04; 1·50; 1·84; 2·16.