Bonn 2010 – wissenschaftliches Programm
HK 31.2: Vortrag
Dienstag, 16. März 2010, 17:00–17:15, HG IX
Results from first beam tests for the development of a RICH detector for CBM — •Jürgen Eschke — GSI, Darmstadt, Germany
The CBM experiment at FAIR will be a dedicated heavy-ion experiment exploring the intermediate range of the QCD phase diagram with A+A collisions from 10-45 AGeV beam energy. A key observable of the physics program is a precise measurement of low-mass vector mesons and charmonium in their leptonic decay channel. In CBM, electrons will be identified using a gaseous RICH detector combined with several TRD detectors positioned behind a system of silicon tracking stations.
The concept of the RICH detector and feasibility studies will be presented. As photodetector, we foresee an array of Multianode Photomultipliers (MAPMTs). First beam test results using the Hamamatsu H8500 MAPMT for Cherenkov light detection as well as measurements in the laboratory using an LED as light source will be discussed. The signals of the MAPMT were read out by a new, especially developed, self triggered readout electronics based on the n-XYTER ADC chip. A 2 GeV proton beam at GSI was used to produced Cherenkov photons in a 8(4) mm plexiglass radiator. The comparison of the expected number of Cherenkov photons with the detected number of hits in the MAPMT will be discussed taking into account the quantum efficiency and photon collection efficiency of the MAPMT as well as the absorption of UV photons in the plexiglass. The usage of wavelength shifter films in order to increase the photon conversion efficiency for wavelengths below 300 nm will also be addressed.