New scintillating bolometer crystals for rare particle detection

The Majorana nature of neutrinos is one of the most important questions being pursued in physics today. This has given the search for neutrinoless double-beta decay (0 nu beta beta) a high priority among proposed nuclear physics experiments. In this work, the objective was to evaluate several crystal compositions for possible use as a scintillating bolometer in 0 nu beta beta research. A crucial characteristic of the investigated crystals is that their compositions must include one of the few elements known to decay with double-beta emission. Therefore, we grew crystals containing molybdenum or selenium as a major constituent. Results are presented here for single-crystals of sodium molybdate and lithium indium diselenide. Scintillating bolometer data were measured at milli-Kelvin temperature and show good discrimination between alpha and beta/gamma emissions, which is crucial for background reduction. The lithium indium diselenide crystal was also used to measure the energy spectrum for the beta emission of indium decay, the first time a beta decay spectrum has been measured from self-emission in a scintillating bolometer.