SMuK 2023 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 56: Instrumentation XV
HK 56.4: Vortrag
Donnerstag, 23. März 2023, 15:00–15:15, SCH/A.101
New "escalation" effect observed in recent MCP-PMTs — •Steffen Krauss, Merlin Boehm, Katja Gumbert, Albert Lehmann, and Daniel Miehling — Physikalisches Institut, Universität Erlangen-Nürnberg
Two DIRC-type Cherenkov detectors will be employed in the PANDA experiment at FAIR for pion/kaon separation. Since the focal planes of both DIRC detectors are located in a 1 Tesla magnetic field, Microchannel-Plate Photomultipliers (MCP-PMTs) are the only viable option to detect the few generated Cherenkov photons. To distinguish these single photons safely from the thermally emitted photo electrons a low darkcount rate is required in combination with a high gain of > 106. In some of the latest MCP-PMTs a new and completely unexpected effect was observed recently. At high gains and sometimes in combination with high illumination levels the MCP-resistance drops significantly, the gain drops, and a high amount of photons are created inside the tube, which causes a drastic increase of count rate. Inside a magnetic field this behavior seems to be significantly suppressed.
To study this effect in more detail several measurements of current, gain, and count rate were performed and compared for different MCP-PMTs. The rate of the produced photons were measured in an oppositely placed additional MCP-PMT. The results of these measurements are presented in this talk for older and the most recent MCP-PMT generations of different manufacturers.
- Funded by BMBF and GSI -