Photoneutron Reaction of S32

Abstract

The photoneutron cross section of S/sup 32/ was observed up to 22 Mev with good energy resolution, together with the photoneutron spectrum using a stilbene scintillation spectrometer. Fine structures were observed in either of the two measurements. Taking into account the threshold energy and the excitation energies of the residual nucleus, these structures were shown to be consistently related with each other. Experimental results were discussed using the statistical model calculation, assuming that the emitted particles were only p-wave and f-wave particles. The integrated cross section ratio for S/sup 32/ ( gamma ,n) to P/sup 31/ ( gamma ,n) reaction and the same ratio for S/sup 32/ ( gamma ,p) to S/sup 32/ ( gamma ,n) reaction were well explained by the calculations. The difference between the energy spectrum of the photoprotons from P/sup 31/ and that from Si/sup 28/ also seemed to be well explained qualitatively. In the appendix, the contributions of the f-wave protons for the energy spectrum of photoprotons were shown. The photodisintegration of nuclei in these mass number region was concluded to occur mainly through the compound process in the giant resonance energy region. (auth)