München 2019 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 7: Instrumentation I

HK 7.5: Talk

Monday, March 18, 2019, 15:15–15:30, HS 11

Gain uniformity measurements of a single GEM — •Mario Engel, Philip Hauer, Michael Hösgen, Markus Ball, and Bernhard Ketzer — Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn

The Gas Electron Multiplier (GEM) is a type of micro-pattern gaseous detector. Optimal performance of detectors based on gas amplification in GEMs requires the gain to be uniform across the active area. Non-uniformities may arise from the production process for GEM foils, e.g. due to varying hole diameters and shapes. The holes of the GEM are etched with a photolithographic process into copper (5 µm)- polyimide (50 µm)- copper (5 µm) layers (standard GEM). Measurements of the uniformity of the gain of a single GEM foil are performed by using a setup consisting of a patterned readout electrode with an integrated bulk Micromegas, above which the GEM foil to be tested is mounted. With these two amplification stages, the effective gain of the GEM can be measured directly. As a radiation source, an ⁵⁵Fe X-ray emitter is used. The gain is measured at different spots over the 10 cm × 10 cm GEM. The talk will present the setup and measurements with different types of GEM foils.

Supported by BMBF