Measurement of cosmic-ray muon spallation products in a xenon-loaded liquid scintillator with KamLAND
S. Abe, S. Asami, M. Eizuka, S. Futagi, A. Gando, Y. Gando, T. Gima, Atsushi Goto, Takahiko Hachiya, K. Hata, K. Hosokawa, K. Ichimura, S. Ieki, H. Ikeda, K. Inoue, K. Ishidoshiro, Y. Kamei, N. Kawada, Y. Kishimoto, M. Koga, M. Kurasawa, T. Mitsui, H. Miyake, T. Nakahata, K. Nakamura, R. Nakamura, H. Ozaki, T. Sakai, I. Shimizu, J. Shirai, K. Shiraishi, A. Suzuki, Y. Suzuki, A. Takeuchi, K. Tamae, H. Watanabe, Y. Yoshida, S. Obara, A. K. Ichikawa, S. Yoshida, S. Umehara, K. Fushimi, Kumiko Kotera, Y. Urano, B. E. Berger, B. K. Fujikawa, J. G. Learned, J. Maricic, Spencer Axani, Z. Fu, J. Smolsky, L. A. Winslow, Y. V. Efremenko, H. J. Karwowski, D. M. Markoff, W. Tornow, S. Dell’Oro, T. O’Donnell, J. A. Detwiler, S. Enomoto, M. P. Decowski, K. M. Weerman, C. Grant, A. Li, H. Song
Abstract
Cosmic-ray muons produce various radioisotopes when passing through material. These spallation products can be backgrounds for rare event searches such as in solar neutrino, double-$\ensuremath{\beta}$ decay, and dark matter search experiments. The KamLAND-Zen experiment searches for neutrinoless double-$\ensuremath{\beta}$ decay in 745 kg of xenon dissolved in liquid scintillator. The experiment includes dead-time-free electronics with a high efficiency for detecting muon-induced neutrons. The production yields of different radioisotopes are measured with a combination of delayed coincidence techniques, newly developed muon reconstruction, and xenon spallation identification methods. The observed xenon spallation products are consistent with results from the fluka and geant4 simulation codes.