Bochum 2009 – scientific programme

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HK: Fachverband Hadronen und Kerne

HK 75: Accelerators and Instrumentation I

HK 75.5: Talk

Thursday, March 19, 2009, 17:45–18:00, H-ZO 80

APD development for the PANDA EMC — •Andrea Wilms — GSI Darmstadt, Darmstadt, Germany

The PANDA experiment is the part of the experimental program of the Facility for Antiproton and Ion Research (FAIR) with highest priority. The electromagnetic calorimeter will consist of nearly 16.000 lead tungstate (PWO) crystals read out with Avalanche Photodiodes which have an internal gain depending on the applied bias voltage. To increase the LY of the scintillator crystals the whole calorimeter will operate at a temperature of T = −25^∘C.
Each crystal of the calorimeter will be read out via two APDs so that a screening procedure for nearly 40.000 APDs has to be build up to ensure the correctness of the required device properties before their mounting on the rear side of the PWO crystals. The screening procedure includes the measurement of the main APD parameters like gain-bias dependence, dark current dependence on the applied voltage, surface uniformity of the gain, etc. To ensure a proper calibration during detector operation all measurements, including the test of radiation hardness, have to be done temperature dependent. The results of the screening of the first large area APDs with rectangular shape (active area: (7 × 14) mm²) will be compared to the results of the first APDs with quadratic shape used in the R&D process for the PANDA EMC readout concept.
This work is supported by EU contract number 506078 Hadron Physics.