Recent progress of GaAsP HPD development for the MAGIC telescope project

TL;DR

This paper reviews recent advancements in GaAsP Hybrid Photon Detectors for the MAGIC telescope, highlighting their high quantum efficiency, low afterpulsing, and long operational lifetime, enhancing low-light detection capabilities.

Contribution

It reports on recent progress in GaAsP HPD development, demonstrating improved performance metrics for Cherenkov telescope applications.

Findings

Quantum efficiency exceeds 50%

Afterpulsing rate is ~300 times lower than PMTs

Operational lifetime exceeds 10 years

Abstract

Today the Hybrid Photon Detector (HPD) is one of the few low light level (LLL) sensors that can provide an excellent single and multiple photoelectron (ph.e.) amplitude resolution. The recently developed HPDs for the MAGIC telescope project with a GaAsP photocathode, namely the R9792U-40, provide a peak quantum efficiency (QE) of more than 50% and a pulse width of ~2 nsec. In addition, the afterpulsing rate of these tubes is very low compared to that of conventional photomultiplier tubes (PMTs), i.e. the value is ~300 times lower. Photocathode aging measurements showed life time of more than 10 years under standard operating conditions of the Cherenkov Telescopes. Here we want to report on the recent progress with the above mentioned HPDs.