Cryogenic CMOS Cameras for High Voltage Monitoring in Liquid Argon

TL;DR

This paper introduces a cryogenic CMOS camera system designed for real-time high voltage and component monitoring inside large liquid argon detectors, demonstrating reliable operation over months and practical application in DUNE 35t cryostat.

Contribution

The paper presents a novel cryogenic CMOS camera system tailored for liquid argon detectors, with detailed characterization and successful deployment in operational environments.

Findings

Reliable operation over several months in cryogenic conditions

Effective monitoring of high voltage breakdowns in liquid argon

Successful in situ observation of detector components during cooldown

Abstract

The prevalent use of large volume liquid argon detectors strongly motivates the development of novel readout and monitoring technology which functions at cryogenic temperatures. This paper presents the development of a cryogenic CMOS camera system suitable for use inside a large volume liquid argon detector for online monitoring purposes. The characterisation of the system is described in detail. The reliability of such a camera system has been demonstrated over several months, and recent data from operation within the liquid argon region of the DUNE 35tcryostat is presented. The cameras were used to monitor for high voltage breakdown inside the cryostat, with capability to observe breakdown of a liquid argon time projection chamber in situ. They were also used for detector monitoring, especially of components during cooldown.