First Results from the Modular Total Absorption Spectrometer at the HRIBF

A Modular Total Absorption Spectrometer constructed at the Holifield Radioactive Ion Beam Facility has been applied to decay studies of over 20 238U fission products. The measurements were focused on nuclei identified as important for decay heat analysis during a nuclear fuel cycle. Preliminary results on the average electromagnetic (EM) energy release in the β decay of 89Kr and 139Xe isotopes yielded values of 2446 keV and 1126 keV, respectively. It represents an increase of over 35% and 20%, respectively, when compared to the average EM energies deduced using the ENSDF database.