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Abstract

The nuclear energy levels of As⁷⁵ have been investigated through the study of the Se⁷⁵ decay scheme. The internal conversion spectrum as well as the photoelectron spectra (using bismuth and lead radiators) were measured with a modified thin lens magnetic spectrometer. A technique was developed for accurate determination of the transmission of the spectrometer in order to obtain the absolute conversion electron transition intensities. The gamma ray intensities were determined from the spectrum measured with a NaI(T1) scintillation spectrometer in conjunction with the results from the photoelectron spectra. From these measurements the absolute conversion coefficients for eight transitions were obtained. In addition coincidence techniques employing a slow- fast coincidence system (resolving time 10⁻⁷ sec) were used to measure gamma-gamma coincidences, conversion electron-gamma coincidences and gamma-gamma directional correlations. A one hundred channel kicksorter was used to facilitate accumulation of the data at the relatively low coincidence counting rates. Multipolarities of the following transitions were determined, (energies in kev), 97(E2); 121(El); 136(El); 199(M1+E2); 265(Ml,-0.12