This paper presents a world-leading scintillation light yield among inorganic crystals measured from a 0.5~kg pure-CsI detector operated at 77 Kelvin. Scintillation photons were detected by two 2-inch Hamamatsu SiPM arrays equipped with cryogenic front-end electronics. Benefiting the light yield enhancement of pure-CsI at low temperatures and the high photon detection efficiency of SiPM, a light yield of 30.1 photoelectrons per keV energy deposit was obtained for X-rays and γ-rays with energies from 5.9~keV to 59.6~keV. Instrumental and physical effects in the light yield measurement are carefully analyzed. This is the first stable cryogenic operation of kg-scale pure-CsI crystal readout by SiPM arrays at liquid nitrogen temperatures for several days. The world-leading light yield opens a door for the usage of pure-CsI crystal in several fields, particularly in detecting the coherent elastic neutrino-nucleus scattering of reactor neutrinos. The potential of using pure-CsI crystals in neutrino physics is discussed in the paper.
@article{arxiv.2212.11515,
title = {Reactor neutrino physics potentials of cryogenic pure-CsI crystal},
author = {L. Wang and G. d. Li and Z. Y. Yu and X. H. Liang and T. A. Wang and F. Liu and X. L. Sun and C. Guo and X. Zhang and L. Yu and Y. D. Chen},
journal= {arXiv preprint arXiv:2212.11515},
year = {2024}
}