Köln 2025 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 11: Instrumentation IV
HK 11.2: Talk
Monday, March 10, 2025, 17:00–17:15, SR Exp1B Chemie
Performance and problems of the latest series production MCP-PMTs for the PANDA Barrel DIRC — •Steffen Krauss, K. Gumbert, A. Lehmann, and D. Miehling — ECAP, Universität Erlangen-Nürnberg
The PANDA experiment at GSI’s Facility for Antiproton and Ion Research (FAIR) in Darmstadt will use DIRC detectors to separate pions and kaons in the 0.5 to 4 GeV/c momentum range. The DIRC focal planes will be located inside the PANDA solenoid magnet. This exposes the photon sensors to a magnetic field of ∼1 T. For this and other reasons, microchannel plate photomultipliers (MCP-PMTs) were the only viable option to efficiently detect the few Cherenkov photons.
A barrel DIRC surrounds the interaction region and consists of 16 radiator sectors, each equipped with 8 MCP-PMTs. The selected PMTs, type PHOTONIS XP85112-S-BA with 10 µm pores, have an area of 2x2 inch2 with 8x8 anode pixels and an ALD coating to increase the lifetime. A total of 165 (128 + 37 spare) tubes are quality evaluated in Erlangen to fulfill the key requirements for the Barrel DIRC.
Essential requirements for the MCP-PMTs are gains of > 106 in a 1 T field, high detective quantum efficiency (QE*CE), high rate capability, ultra-fast time response and good spatial homogeneity of QE and gain. Internal parameters such as dark count rate, crosstalk and afterpulse fractions are measured with a TRB/DiRICH DAQ system. The main conclusions for meanwhile >80 surveyed PMTs are presented, as well as some severe PMT issues encountered during the evaluation process.
- Funded by BMBF and GSI -