Scintillation in Low-Temperature Particle Detectors

Abstract

Inorganic crystal scintillators play a crucial role in particle detection for various applications in fundamental physics and applied science. The use of such materials as scintillating bolometers, which operate at temperatures as low as 10 mK and detect both heat (phonon) and scintillation signals, significantly extends detectors performance compared to the conventional scintillation counters. In particular, such low-temperature devices offer a high energy resolution in a wide energy interval thanks to a phonon signal detection, while a simultaneous registration of scintillation emitted provides an efficient particle identification tool. This feature is of great importance for a background identification and rejection. Combined with a large variety of elements of interest, which can be embedded in crystal scintillators, scintillating bolometers represent powerful particle detectors for rare-event searches (e.g., rare alpha and beta decays, double-beta decay, dark matter particles, neutrino detection). Here, we review the features and results of low-temperature scintillation detection achieved over a 30-year history of developments of scintillating bolometers and their use in rare-event search experiments.

Final results on the $0νββ$ decay half-life limit of $^{100}$Mo from the CUPID-Mo experiment

“…Scintillating calorimeters are one of the most promising current technologies for 0𝜈𝛽𝛽 decay searches, with many possible configurations [16,[30][31][32][33][34][35][36]. These consist of a crystalline material, containing the source isotope, capable of scintillating at low temperatures which is operated as a cryogenic calorimeter coupled to light detectors to detect scintillation light.…”

Optimization of the first CUPID detector module

“…An antireflecting 60 nm thick layer of SiO [66] was deposited on both sides of the Ge faces to increase the light collection, as already done in CUPID-Mo [56]. This is the most reliable technology to be operated at cryogenic temperatures to detect scintillation light from the crystals, which typically corresponds to an equivalent deposition of keV per MeV of energy deposit in the crystal [49,51,56,58,67]. We tested 2 possible configurations of the LDs as outlined in Fig.…”

Assessment of Cs2HfCl6 crystal applicability as low-temperature scintillating bolometers by their thermodynamic characteristics

“…ref. 16). To do so, we calibrated the LD using the muon event distribution 60 (to obtain an absolute calibration; see Fig.…”

“…Indeed, the applicability of this experimental technique has been demonstrated in the field of rare nuclear decay searches in numerous successful experiments. 16 The experimental sensitivity achieved with this technique spans in the range of 10 16 –10 25 years if one would consider rare processes such as alpha, strongly forbidden beta and neutrinoless double beta decay. Such a high sensitivity can be explained by a simultaneous recording of scintillating pulses and phonon signals from each individual interaction event, which allows for a highly effective particle identification and, consequently, for efficient background reduction.…”