Scientific Results

Cryogenic light detectors with enhanced performance for rare event physics

Year: 2019

Authors: Barucci M., Beeman JW., Caracciolo V., Pagnanini L., Pattavina L., Pessina G., Pirro S., Rusconi C., Schaffner K.

Autors Affiliation: CNR, Ist Nazl Ott, I-50125 Florence, FI, Italy; Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA; Ist Nazl Fis Nucl, Lab Nazl Gran Sasso, I-67100 Assergi, AQ, Italy; Univ Milano Bicocca, Dipartimento Fis, I-20126 Milan, Italy; Ist Nazl Fis Nucl, Sez Milano Bicocca, Milan, Italy; Gran Sasso Sci Inst, I-67100 Laquila, Italy; Univ South Carolina, Dept Phys & Astron, Columbia, SC 29208 USA; Tech Univ Munich, Munich, Germany

Abstract: We have developed and tested a new way of coupling bolometric light detectors to scintillating crystal bolometers based upon simply resting the light detector on the crystal surface, held in position only by gravity. This straightforward mounting results in three important improvements: (1) it decreases the amount of non-active materials needed to assemble the detector, (2) it substantially increases the light collection efficiency by minimizing the light losses induced by the mounting structure, (3) and it enhances the thermal signal induced in the light detector thanks to the extremely weak thermal link to the thermal bath. We tested this new technique with a 16 cm(2) Ge light detector with thermistor readout sitting on the surface of a large TeO2 bolometer. The light collection efficiency was increased by greater than 50% compared to previously tested alternative mountings. We obtained a baseline energy resolution on the light detector of 20 eV RMS that, together with increased light collection, enabled us to obtain the best alpha vs beta/gamma discrimination ever obtained with massive TeO2 crystals. At the same time we achieved rise and decay times of 0.8 and 1.6 ms, respectively. This superb performance meets all of the requirements for the CUPID (CUORE Upgrade with Particle IDentification) experiment, which is a 1-ton scintillating bolometer follow up to CUORE.

Journal/Review: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT

Volume: 935      Pages from: 150  to: 155

KeyWords: Double beta decay; Dark matter; Scintillating bolometers; Cherenkov radiation; Particle identification methods; Cryogenic detectors
DOI: 10.1016/j.nima.2019.05.019

Citations: 2
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