Lowering the energy threshold of large-mass bolometric detectors

Large-mass bolometers are used in particle physics experiments to search for rare processes. The energy threshold of such detectors plays a critical role in their capability to search for dark matter interactions and rare nuclear decays. We have developed a trigger and a pulse shape algorithm based on the matched filter technique which, when applied to data from test bolometers of the CUORE experiment, lowered the energy threshold from tens of keV to the few keV region. The detection efficiency is in excess of 80%, and nearly all nonphysical pulses are rejected.