Gamma-Ray Spectrum ofAs77

Abstract

The gamma-ray spectrum following the beta decay of ${\mathrm{As}}^{77}$ was investigated by means of a scintillation spectrometer. The following gamma-ray energies (in kev) and intensities (quanta per disintegration) were observed: 88(0.003); 155(∼0.002); 243(0.023); 528(0.007). Coincidence experiments show that the 88-and 155-kev lines are emitted in cascade, while the other two lines do not coincide with any other. A level diagram for the product nucleus ${\mathrm{Se}}^{77}$ is suggested.