Mainz 2022 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 58: Instrumentation XIV
HK 58.4: Vortrag
Donnerstag, 31. März 2022, 14:45–15:00, HK-H3
Lifetime and Performance of the very latest Microchannel-Plate Photomultipliers — •Daniel Miehling, Merlin Böhm, Katja Gumbert, Steffen Krauss, and Albert Lehmann for the PANDA collaboration — Physikalisches Institut, Universität Erlangen-Nürnberg
Two DIRC detectors will be used for particle identification and in particular pion/kaon separation at the PANDA experiment at FAIR. The focal planes of both DIRCs will reside in a magnetic field of up to 2 Tesla. This and other constraints leave the usage of Microchannel-Plate Photomultipliers (MCP-PMTs) as the only option. A few years ago the most limiting parameter was the lifetime of the MCP-PMTs. During operation feedback ions produced in the residual gas and during electron multiplication at the MCP walls are accelerated towards the photo cathode and may damage it. This leads to a sizable quantum efficiency (QE) drop with increasing integrated anode charge. Coating the MCPs by applying an atomic-layer deposition technique (ALD) increased the lifetime drastically. Another important parameter is the detective quantum efficiency (DQE) which is the product of the QE and the difficult to measure collection efficiency (CE). This should also be as high as possible to detect as many Cherenkov photons as possible. Recently tubes with CE values of close to 100% are available. In this talk the results of these performance parameters will be presented and discussed along with an overview of the general performance of the very latest ALD-coated 2x2 inch2 MCP-PMTs with 8x8 anode pixels from Photek and PHOTONIS. - Funded by BMBF and GSI -