Determining Beta Feeding Intensities and Level Schemes of Tc-106 and Mo-106 Using The Modular Total Absorption Spectrometer*

Nuclear data for fission fragment isotopes is an area of research that is extremely important for many industrial and academic fields. When fission fragments decay, they can result in nuclei with many high energy levels being fed, each with a relatively low intensity. This is called the pandemonium effect. High precision spectroscopy measurements will typically vastly underestimate the beta feeding intensities to the high energy levels, and overestimate the lower energy levels. The solution to this is Total Absorption Spectroscopy (TAS). My research regarding Tc-106 and Mo-106 has data obtained using the Modular Total Absorption Spectrometer (MTAS) at Argonne National Laboratory's CARIBU source. MTAS is a segmented NaI detector with over 80% efficiency, allowing for the observance of high energy levels in nuclei. By utilizing the modular segmented NaI crystals, in combination with extremely efficient beta gating via silicon strips, it is possible to determine both the beta feeding intensities and the gamma decay paths from nuclei, which can not easily be done with HPGe detectors. This data can then be fed into physics codes such as MCNP and GEANT4, resulting in far better simulation quality for both the nuclear physics and engineering communities.