| Autor: |
Collaboration, The MAJORANA, Arnquist, IJ, III, FT Avignone, Barabash, AS, Barton, CJ, Bertrand, FE, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Drobizhev, A, Edwards, TR, Edwins, DW, Efremenko, Yu, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hegedus, RJ, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kim, I, Kouzes, RT, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, Oli, TK, Othman, G, Pettus, W, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Ruof, NW, Saykı, B, önert, S Sch, Stortini, MJ, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Willers, M, Wiseman, C, Xu, W, Yu, C-H, Zhu, BX |
| Rok vydání: |
2020 |
| Předmět: |
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| Popis: |
P-type point contact (PPC) HPGe detectors are a leading technology for rare event searches due to their excellent energy resolution, low thresholds, and multi-site event rejection capabilities. We have characterized a PPC detector's response to $\alpha$ particles incident on the sensitive passivated and p+ surfaces, a previously poorly-understood source of background. The detector studied is identical to those in the MAJORANA DEMONSTRATOR experiment, a search for neutrinoless double-beta decay ($0\nu\beta\beta$) in $^{76}$Ge. $\alpha$ decays on most of the passivated surface exhibit significant energy loss due to charge trapping, with waveforms exhibiting a delayed charge recovery (DCR) signature caused by the slow collection of a fraction of the trapped charge. The DCR is found to be complementary to existing methods of $\alpha$ identification, reliably identifying $\alpha$ background events on the passivated surface of the detector. We demonstrate effective rejection of all surface $\alpha$ events (to within statistical uncertainty) with a loss of only 0.2% of bulk events by combining the DCR discriminator with previously-used methods. The DCR discriminator has been used to reduce the background rate in the $0\nu\beta\beta$ region of interest window by an order of magnitude in the MAJORANA DEMONSTRATOR, and will be used in the upcoming LEGEND-200 experiment. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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