Studies of helium poisoning of a Hamamatsu R5900-00-M16 photomultiplier

TL;DR

This study investigates helium poisoning effects on a Hamamatsu photomultiplier tube, revealing increased after-pulsing with helium exposure but minimal gain loss, indicating resilience.

Contribution

It provides experimental evidence of helium-induced after-pulses and quantifies the relationship between helium exposure time and after-pulsing probability.

Findings

After-pulsing probability increases linearly with helium exposure

Gain reduction remains minimal despite helium contamination

Photomultiplier shows resilience to helium poisoning

Abstract

We report results from studies of the helium poisoning of a 16-anode photomultiplier tube R5900-00-M16 manufactured by Hamamatsu Photonics. A tube was immersed in pure helium for a period of about four months and was periodically monitored using a digital oscilloscope. Our results are based on the analysis of waveforms triggered by the dark noise pulses. Collected data yield evidence of after-pulses due to helium contamination of the tube. The probability of after-pulsing increased linearly with the exposure time to helium but the phototube suffered only a small drop in gain, indicating generally strong resilience to helium poisoning.