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Description
This study investigates the damage threshold and recovery time of photomultiplier tubes (PMTs) with bialkali metal coatings, focusing on their quantum efficiency (QE) degradation under intense light exposure and thermal stress. To simulate prolonged sunlight exposure, PMTs were subjected to a xenon lamp for varying durations, with QE measured before and after exposure. Similarly, thermal stress tests were conducted to evaluate performance under elevated temperatures. A dedicated absorption spectroscopy setup, based on a laser diode emitting on the D2 cesium absorption line at 852 nm was implemented to monitor in real time during stress tests, the potential detachment from the photo-cathode and diffusion of cesium atoms within the PMT bulb, which may contribute to QE loss.
