Dresden 2013 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 23: Instrumentation

HK 23.4: Talk

Monday, March 4, 2013, 17:45–18:00, WIL-A221

Stimulated Recovery of Radiation Damage for the PANDA EMC — Till Kuske, •Valera Dormenev, and Rainer Novotny — Justus-Liebig-Universität, Gießen

The future Electromagnetic Calorimeter (EMC) of the PANDA detector at FAIR will be based on a new generation of lead tungstate crystals (PWO-II). It is optimized to measure particle energies from 10 GeV down to 10-20 MeV. The operating temperature of the EMC will be -25°C. Due to the operation in a strong radiation environment one of the most critical parameter of PWO-II is radiation hardness. The radiation damage of PWO-II can be compensated by spontaneous relaxation of the color centers via thermo-activation. The process is strongly suppressed at -25°C, which is limiting the energy resolution of the EMC. The recovery process can be accelerated by illumination of the crystal with light even in the infrared region.The applicability of this process is being studied for implementation primarily into the most forward region of the target spectrometer dealing with the highest rate of radiation damage. The present paper will discuss the conditions for on- and off-line operation for both considered photo sensors such as LAAPDs and VPTT tubes. The effectiveness and wavelength sensitivity will be shown and discussed based on recent experimental data using LEDs as well as LASER diodes as light sources.

This Project has been supported by BMBF