Performance evaluation of GYGAG crystals for neutrinoless double beta decay search

Hibiki Hayasaki; Keishi Hosokawa; Koichi Ichimura; Shunsuke Kurosawa; Yuta Masaki; Yusuke Mizuno; Yasuhiro Nakajima; Hiroyuki Sekiya; Akihiro Yamaji

arXiv · 2605.28414

Performance evaluation of GYGAG crystals for neutrinoless double beta decay search

Hibiki Hayasaki·Keishi Hosokawa·Koichi Ichimura·Shunsuke Kurosawa·Yuta Masaki·Yusuke Mizuno·Yasuhiro Nakajima·Hiroyuki Sekiya·Akihiro Yamaji

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Abstract

Neutrinoless double beta decay (0$\nu\beta\beta$) is a crucial for confirming neutrinos' Majorana characteristics. Previous searches for 0$\nu\beta\beta$ decay of $^{160}$Gd using GSO crystals was conducted, but the sensitivity was limited by background $\alpha$-rays from radioactive impurities. To distinguish the backgrounds, PSD (Pulse Shape Discrimination) and energy resolution are essential. GAGG (Gd$_{3}$(Al, Ga)$_5$O$_{12}$) is a $^{160}$Gd-containing crystal that exhibits a higher light yield than GSO and excellent PSD capabilities. GYGAG (Gd$_{3-x}$Y$_x$(Al, Ga)$_5$O$_{12}$) is a variant crystal where a portion of Gd is substituted with Yttrium and can have enhanced light yield, motivating its investigation for 0$\nu\beta\beta$ decay searches. In this study, GYGAG crystals with different Yttrium concentrations were fabricated and their energy resolution, pulse shape discrimination capability between $\alpha$ and $\gamma$ rays, and scintillation timing characteristics were evaluated for applications in 0$\nu\beta\beta$ decay searches. Y substitution enhanced the light yield, and the best energy resolution was achieved for Gd$_{2.5}$Y$_{0.5}$Al$_2$Ga$_3$O$_{12}$. GYGAG exhibited high pulse shape discrimination performance across various yttrium concentrations.

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Hibiki Hayasaki, Keishi Hosokawa, Koichi Ichimura, Shunsuke Kurosawa, Yuta Masaki, Yusuke Mizuno, Yasuhiro Nakajima, Hiroyuki Sekiya, Akihiro Yamaji. 2026-05-27. Performance evaluation of GYGAG crystals for neutrinoless double beta decay search. https://arxiv.org/abs/2605.28414

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