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HK: Fachverband Physik der Hadronen und Kerne
HK 28: Instrumentation und Anwendungen
HK 28.1: Talk
Wednesday, March 14, 2007, 11:15–11:30, B
A highly integrated low-cost readout system for the COMPASS RICH detector — Bernhard Ketzer, Heinz Angerer, Sergei Gerassimov, •Igor Konorov, Alexander Mann, and Stephan Paul — Technische Universität München, Physik Department, 85748 Garching, Germany
Particle identification at high multiplicities is a key feature of the COMPASS experiment at CERN’s SPS. Hadrons up to 50 GeV/c are identified by a RICH detector with a large horizontal and vertical acceptance of ± 250 mrad and ± 180 mrad, respectively. Cherenkov photons created in the C4F10 radiator gas are focused by a mirror wall onto the photon detectors. While the central region is equipped with multi-anode photomultiplier tubes, the remaining 75% of the total active area are covered by MWPCs with CsI photocathodes.
In order to improve the performance of the detector at very high beam intensities, more than 62000 channels of a new analog readout system of the MWPCs, based on the APV25 chip, were developed and installed in 2006. The new system features good single photon detection efficiency due to its low noise, negligible dead time at trigger rates up 50 kHz, and low cost. In addition, sampling of the MWPC signal allows us to measure the signal time with a resolution of ∼ 30 ns or better, thus considerably reducing the background due to pile-up.
The architecture of the new readout system as well as first results on the performance of the RICH detector in 2006 will be discussed.
This work is supported by BMBF and Maier-Leibnitz-Labor der TU und LMU München.