Bonn 2010 – wissenschaftliches Programm
HK 36.46: Poster
Mittwoch, 17. März 2010, 14:00–16:00, HG Aula
Quality Control of Lead Tungstate Crystals for the PANDA-EMC — •Tobias Eißner, Valera Dormenev, Rainer Novotny, and Werner Döring — II. Physikalisches Institut, Universität Giessen
The electromagnetic calorimeter of the target spectrometer of PANDA relies on the high quality of the scintillator material PbWO4. Up to now 7,355 lead tungstate crystals have been delivered by the supplier BTCP at Bogoroditsk (Russia) which are also completely analyzed with respect to the specification limits. The crystals on hand comprise both endcaps and parts of the barrel. In addition, several simulations were performed with the ROOT add-on LITRANI in order to estimate the uncertainties in the determination of the radiation hardness due to multiple reflected photons in transmission measurements and differences of light collection due to the different crystal shapes. Important correlations for radiation hardness and light yield at T=−25∘C and room temperature were confirmed to guarantee the perfromance at the final operating temperature.
This contribution describes in detail the test procedures and devices at the individual test stations (BTCP, CERN and Giessen) for the measurement of geometrical parameters, optical and scintillation properties. It discusses the results of the simulations and gives an overview of the achieved crystal quality in the rejection rate. Work supported by BMBF and GSI.