Optimizing the energy threshold of light detectors coupled to luminescent bolometers

Bolometers have proven to be good detectors for the search of neutrinoless double beta decay. By operating at cryogenic temperatures, they feature excellent energy resolution and low background. The detection of the possible light emitted when particles interact in the bolometer is a promising method to lower the background of the experiments. The different amount of light emitted in β/γ and α interactions, whether due to scintillation or Cerenkov emission, allows to discriminate the two interaction types. Because of the cryogenic environment, light detectors are often bolometers. In this work we present a software algorithm to lower the energy threshold of bolometric light detectors coupled to luminescent bolometers. The application to data from Ge light detectors coupled to ZnMoO 4 and TeO 2 bolometers shows that the energy threshold can be lowered substantially, increasing the discrimination power when the amount of emitted light is small. © 2011 IOP Publishing Ltd and SISSA.