Offline tagging of radon-induced backgrounds in XENON1T and applicability to other liquid xenon detectors
Creators: name: Aprile, E.
name: Aalbers, J.
name: Abe, K.
name: Maouloud, S. Ahmed
name: Althueser, L.
name: Andrieu, B.
name: Angelino, E.
name: Angevaare, J. R.
name: Martin, D. Antón
name: Arneodo, F.
name: Baudis, L.
name: Baxter, A. L.
name: Bazyk, M.
name: Bellagamba, L.
name: Biondi, R.
name: Bismark, A.
name: Brookes, E. J.
name: Brown, A.
name: Bruno, G.
name: Budnik, R.
name: Bui, T. K.
name: Cardoso, J. M. R.
name: Chavez, A. P. Cimental
name: Colijn, A. P.
name: Conrad, J.
name: Cuenca-García, J. J.
name: D'Andrea, V.
name: Garcia, L. C. Daniel
name: Decowski, M. P.
name: Di Donato, C.
name: Di Gangi, P.
name: Diglio, S.
name: Eitel, K.
name: Elykov, A.
name: Ferella, A. D.
name: Ferrari, C.
name: Fischer, H.
name: Flehmke, T.
name: Flierman, M.
name: Fulgione, W.
name: Fuselli, C.
name: Gaemers, P.
name: Gaior, R.
name: Galloway, M.
name: Gao, F.
name: Ghosh, S.
name: Glade-Beucke, R.
name: Grandi, L.
name: Grigat, J.
name: Guan, H.
name: Guida, M.
name: Hammann, R.
name: Higuera, A.
name: Hils, C.
name: Hoetzsch, L.
name: Hood, N. F.
name: Iacovacci, M.
name: Itow, Y.
name: Jakob, J.
name: Joerg, F.
name: Joy, A.
name: Kaminaga, Y.
name: Kara, M.
name: Kavrigin, P.
name: Kazama, S.
name: Kobayashi, M.
name: Kopec, A.
name: Kuger, F.
name: Landsman, H.
name: Lang, R. F.
name: Levinson, L.
name: Li, I.
name: Li, S.
name: Liang, S.
name: Lin, Y. T.
name: Lindemann, S.
name: Lindner, M.
name: Liu, K.
name: Loizeau, J.
name: Lombardi, F.
name: Long, J.
name: Lopes, J. A. M.
name: Luce, T.
name: Ma, Y.
name: Macolino, C.
name: Mahlstedt, J.
name: Mancuso, A.
name: Manenti, L.
name: Marignetti, F.
name: Undagoitia, T. Marrodán
name: Martens, K.
name: Masbou, J.
name: Masson, E.
name: Mastroianni, S.
name: Melchiorre, A.
name: Messina, M.
name: Michael, A.
name: Miuchi, K.
name: Molinario, A.
name: Moriyama, S.
name: Morå, K.
name: Mosbacher, Y.
name: Murra, M.
name: Müller, J.
name: Ni, K.
name: Oberlack, U.
name: Paetsch, B.
name: Palacio, J.
name: Pan, Y.
name: Pellegrini, Q.
name: Peres, R.
name: Peters, C.
name: Pienaar, J.
name: Pierre, M.
name: Plante, G.
name: Pollmann, T. R.
name: Principe, L.
name: Qi, J.
name: Qin, J.
name: García, D. Ramírez
name: Rajado, M.
name: Shi, J.
name: Singh, R.
name: Sanchez, L.
name: Santos, J. M. F. dos
name: Sarnoff, I.
name: Sartorelli, G.
name: Schreiner, J.
name: Schulte, D.
name: Schulte, P.
name: Eißing, H. Schulze
name: Schumann, M.
name: Lavina, L. Scotto
name: Selvi, M.
name: Semeria, F.
name: Shagin, P.
name: Shi, S.
name: Silva, M.
name: Simgen, H.
name: Takeda, A.
name: Tan, P. -L.
name: Terliuk, A.
name: Thers, D.
name: Toschi, F.
name: Trinchero, G.
name: Tunnell, C.
name: Tönnies, F.
name: Valerius, K.
name: Vecchi, S.
name: Vetter, S.
name: Volta, G.
name: Weinheimer, C.
name: Weiss, M.
name: Wenz, D.
name: Wittweg, C.
name: Wolf, T.
name: Wu, V. H. S.
name: Xing, Y.
name: Xu, D.
name: Xu, Z.
name: Yamashita, M.
name: Yang, L.
name: Ye, J.
name: Yuan, L.
name: Zavattini, G.
name: Zhong, M.
name: Zhu, T.
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: This paper details the first application of a software tagging algorithm to reduce radon-induced backgrounds in liquid noble element time projection chambers, such as XENON1T and XENONnT. The convection velocity field in XENON1T was mapped out using $^{222}\text{Rn}$ and $^{218}\text{Po}$ events, and the root-mean-square convection speed was measured to be $0.30 \pm 0.01$ cm/s. Given this velocity field, $^{214}\text{Pb}$ background events can be tagged when they are followed by $^{214}\text{Bi}$ and $^{214}\text{Po}$ decays, or preceded by $^{218}\text{Po}$ decays. This was achieved by evolving a point cloud in the direction of a measured convection velocity field, and searching for $^{214}\text{Bi}$ and $^{214}\text{Po}$ decays or $^{218}\text{Po}$ decays within a volume defined by the point cloud. In XENON1T, this tagging system achieved a $^{214}\text{Pb}$ background reduction of $6.2^{+0.4}_{-0.9}\%$ with an exposure loss of $1.8\pm 0.2 \%$, despite the timescales of convection being smaller than the relevant decay times. We show that the performance can be improved in XENONnT, and that the performance of such a software-tagging approach can be expected to be further improved in a diffusion-limited scenario. Finally, a similar method might be useful to tag the cosmogenic $^{137}\text{Xe}$ background, which is relevant to the search for neutrinoless double-beta decay.
description: 17 pages, 19 figures