Coincidence Studies of the Disintegration ofPm151andNd147

Abstract

Chemically pure ${\mathrm{Nd}}_2$ ${\mathrm{O}}_3$ was irradiated by slow neutrons on five successive occasions in the Brookhaven pile. The 27.5-hour ${\mathrm{Pm}}^{151}$ was found to emit gamma rays of energies 64, 100, 163, 177, 240, 275, 340, 440, 650, and 700 kev. The 11-day ${\mathrm{Nd}}^{147}$ was shown to emit quanta of energies 92, 165, 280, 320, 410, 440, 530, and 690 kev. The relative intensities of the various quantum radiations have been determined, and coincidence measurements have been performed to ascertain the various sequential relationships between pairs of gamma rays. Partial decay schemes for both radionuclides have been indicated.