https://doi.org/10.1140/epjc/s10052-026-15418-4
Regular Article - Experimental Physics
Performance of a large-volume cryogenic pure CsI detector for CE
NS and low-energy rare-event searches
School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
a
This email address is being protected from spambots. You need JavaScript enabled to view it.
Received:
22
September
2025
Accepted:
6
February
2026
Published online:
28
February
2026
Abstract
A cryogenic detector system based on two 3.3 kg high-purity CsI crystals was developed and characterized at approximately 95 K. Each crystal was coupled to dual-ended 3-inch photomultiplier tubes (PMTs) for scintillation readout. The measured light yields were 
and 
photoelectrons per keV electron-equivalent (PE/keV
) for the two crystals, with corresponding energy resolutions of 7.2% and 7.7% (FWHM) at 59.6 keV. The detector demonstrated excellent spatial uniformity, low intrinsic radioactivity, and stable operation over a continuous one-month period. Optical photon simulations using Geant4 reproduced the observed light collection trends, providing guidance for detector optimization. These results establish cryogenic pure CsI as a scalable technology for low-threshold rare-event searches.
Chen’guang Su and Lingquan Kong have contributed equally to this work.
© The Author(s) 2026
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Funded by SCOAP3.
