Pulse shape discrimination in CUPID-Mo using principal component analysis

Huang, R.; Armengaud, E.; Augier, C.; Barabash, A. S.; Bellini, F.; Benato, G.; Benoît, A.; Beretta, M.; Bergé, L.; Billard, J.; Borovlev, Yu. A.; Bourgeois, Ch.; Brudanin, V. B.; Camus, P.; Cardani, L.; Casali, N.; Cazes, A.; Chapellier, M.; Charlieux, F.; de Combarieu, M.; Dafinei, I.; Danevich, F. A.; De Jesus, M.; Dixon, T.; Dumoulin, L.; Eitel, K.; Ferri, F.; Fujikawa, B. K.; Gascon, J.; Gironi, L.; Giuliani, A.; Grigorieva, V. D.; Gros, M.; Guerard, E.; Helis, D. L.; Huang, H. Z.; Johnston, J.; Juillard, A.; Khalife, H.; Kleifges, M.; Kobychev, V. V.; Kolomensky, Yu. G.; Konovalov, S. I.; Loaiza, P.; Ma, L.; Makarov, E. P.; de Marcillac, P.; Mariam, R.; Marini, L.; Marnieros, S.; Misiak, D.; Navick, X. -F.; Nones, C.; Norman, E. B.; Olivieri, E.; Ouellet, J. L.; Pagnanini, L.; Pari, P.; Pattavina, L.; Paul, B.; Pavan, M.; Peng, H.; Pessina, G.; Pirro, S.; Poda, D. V.; Polischuk, O. G.; Previtali, E.; Redon, Th.; Rozov, S.; Rusconi, C.; Sanglard, V.; Scarpaci, J. A.; Schäffner, K.; Schmidt, B.; Shen, Y.; Shlegel, V. N.; Siebenborn, B.; Singh, V.; Tomei, C.; Tretyak, V. I.; Umatov, V. I.; Vagneron, L.; Velázquez, M.; Weber, M.; Welliver, B.; Winslow, L.; Xue, M.; Yakushev, E.; Zarytskyy, M. M.; Zolotarova, A. S.

doi:10.1088/1748-0221/16/03/P03032

CUPID-Mo is a cryogenic detector array designed to search for neutrinoless double-beta decay (0νββ) of 100Mo. It uses 20 scintillating 100Mo-enriched Li2MoO4 bolometers instrumented with Ge light detectors to perform active suppression of α backgrounds, drastically reducing the expected background in the 0νββ signal region. As a result, pileup events and small detector instabilities that mimic normal signals become non-negligible potential backgrounds. These types of events can in principle be eliminated based on their signal shapes, which are different from those of regular bolometric pulses. We show that a purely data-driven principal component analysis based approach is able to filter out these anomalous events, without the aid of detector response simulations.