(n,2n) and (n,p) Cross Sections

Cross sections of several ($n,2n$) and ($n,p$) reactions were measured by bombarding samples with a known flux of neutrons and measuring the induced beta-activity, making elaborate corrections for self-absorption of the beta-rays. Using the known energy spectrum of the incident neutrons, calculations were made of the cross sections to be expected from Weisskopf's statistical theory, and the agreement was satisfactory. The results indicate that level densities in odd-odd nuclei are greater than those in even-even nuclei by a factor of 3±1. Applications of the method to shielding and the use of threshold detectors are discussed.