Precision Measurement of Transition and Level Energies in 233U

Abstract

Abstract Gamma ray energies in 233U following the decay of 233Pa were measured with the Risö bent crystal spectrometer. These gamma lines were detected during the study of the 232Th(n,y)233Th reaction. Experimental details will be given elsewhere1. The energies were calibrated with the X-ray lines2 and the annihilation line3. The energies of seven transitions between 270 and 420 keV were determined with an accuracy which is up to a factor of 10 better than previous measurements by Albridge, Hollander, Gallagher, and Hamilton4. The transition energies are shown in the level scheme 4, 5 (Fig. 1 ) . A least squares program was used to fit the level energies to the seven transition energies obtained in this experiment and to four transition energies (below 103 keV) measured precisely by Albridge et al. 4. Level energies could be calculated with an accuracy of about 20 eV (Fig. 1).