High granularity tracker based on a Triple-GEM optically read by a CMOS-based camera

Understand

The detection of photons produced during the avalanche development in gas chambers has been the subject of detailed studies in the past.

• The great progresses achieved in last years in the performance of micro-pattern gas detectors on one side and of photo-sensors on the other provide the possibility of making high granularity and very sensitive particle trackers.
• In this paper, the results obtained with a triple-GEM structure read-out by a CMOS based sensor are described.
• The use of an He/CF$_4$ (60/40) gas mixture and a detailed optimization of the electric fields made possible to obtain and very high GEM light yield.