Gießen 2024 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 40: Instrumentation X

HK 40.1: Talk

Wednesday, March 13, 2024, 15:45–16:00, HBR 19: C 2

Magnetic field performance of recent 2-inch MCP-PMTs — •Steffen Krauss, Merlin Böhm, Mirijam Götz, Katja Gumbert, Albert Lehmann, and Daniel Miehling — FAU Erlangen

The PANDA experiment at FAIR will employ two Cherenkov detectors of the DIRC-type for pion/kaon separation. Since the focal planes of both DIRC detectors are located in a 1 Tesla B-field, Microchannel-Plate Photomultipliers (MCP-PMTs) are the only viable option to detect the generated Cherenkov photons. Their magnetic field performance is a key feature of the MCP-PMTs and was investigated at conditions similar to those of the later experiment. MCP-PMTs from Photonis with 10 micrometer pores and an anode layout with 8x8 and 3x100 pixels were compared.

An important characteristic is the gain behavior as a function of the B-field strength and direction. But also the effect of the B-field on the electron trajectories inside the PMT need to be studied. This includes the focussing and spatial displacements of the charge cloud which lead to geometric shifts (e.g. Lorentz) of its center of gravity. The effects of electron focussing and shift were measured and compared to dedicated simulations.

In addition, afterpulses were studied as a function of the B-field strength by analyzing measurements with a CAEN digitizer (and a TRB/PADIWA DAQ system).

- Funded by BMBF and GSI -

Keywords: PMT; MCP-PMT; magnetic field