Berlin 2005 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 22: Postersitzung
HK 22.52: Poster
Montag, 7. März 2005, 16:30–18:00, TU MA141
APD-Readout of PbWO4 Scintillator Arrays — •Michaela Thiel — 2nd Physics Institute, University Giessen
The EM calorimeter of the future PANDA detector, located inside a superconducting solenoid, considers PbWO 4 as scintillator material due to its short radiation length, fast response and moderate costs. The readout of the calorimeter modules within the magnetic field (<2T) can be performed using large area avalanche photo diodes (APD). In spite of the significant improvement of the performance of PWO, the photosensor readout has to cope with a small number of scintillation photons per MeV deposited energy. Therefore, large area APDs have been developed, tested and operated at temperatures well below room temperature. To optimize low energy photon detection, a number of low noise charge sensitive preamplifiers has been developed using discrete components. First experiments have been performed with several arrays of large crystals to measure the energy and time response to monoenergetic photons up to 800 MeV at MAMI. The operation at low temperatures imposes strong requirements on temperature and bias voltage stability. The applicability of alternative photosensors will be discussed in comparison. The work is supported by BMBF, GSI and EU within the I3 Hadron Physics project.