PHOTONEUTRON CROSS SECTIONS FOR SN-116, SN-117, SN-118, SN-119, SN-120, SN-124, AND INDIUM

Monochromatic photons obtained from the annihilation in flight of fast positrons were used to measure photoneutron cross sections for a number of tin isotopes and indium. Total cross sections for Sn116, Sn117, Sn118, Sn119, Sn120, Sn124, and In have peak values of 266, 254, 255, 253, 280, 283, and 266 mb at energies of 15.67, 15.66, 15.60, 15.54, 15.40, 15.18, and 15.63 MeV, respectively. The respective integrated cross sections were found to be 1.67, 1.89, 1.85, 2.00, 2.07, 2.01, and 1.88 MeV b; while the respective (2n) integrated cross sections were 0.414, 0.475, 0.531, 0.598, 0.673, 0.670, and 0.509 MeV b. Single-nucleon effects on the giant resonance were examined, and shell effects have been determined. Other nuclear quantities determined include nuclear level densities, pairing energies, and integrated moments. © 1969 The American Physical Society.