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HK: Fachverband Physik der Hadronen und Kerne
HK 48: Poster
HK 48.49: Poster
Wednesday, March 25, 2015, 17:00–19:00, C/Foyer
Optical properties of the PANDA Barrel DIRC radiator bars — Grzegorz Kalicy1,2, •Marvin Krebs1,2, Klaus Peters1,2, Carsten Schwarz1, and Jochen Schwiening1 for the PANDA collaboration — 1GSI, Darmstadt — 2Goethe Universität, Frankfurt
The PANDA experiment at the Facility for Antiproton and Ion Research in Europe (FAIR) at GSI, Darmstadt, will study fundamental questions of hadron physics and QCD. A fast focusing DIRC (Detection of Internally Reflected Cherenkov light) counter will provide hadronic particle identification (PID) in the barrel region of the PANDA detector. To meet the PID requirements, the Barrel DIRC has to provide precise measurements of the Cherenkov angle, which is conserved for Cherenkov photons propagating through the radiator by total internal reflection. The radiators, rectangular bars made from fused silica, have to fulfill very strict optical and mechanical requirements. This includes the squareness and parallelism of the sides of the bars, sharp corners, and a very smooth surface polish, ensuring that the Cherenkov photons reach the optical sensors without angular distortions. Currently the Barrel DIRC is at the final design stage and several different bar shapes and fabrication methods are being considered for the final detector. An optical setup, consisting of a computer-controlled positioning and a multi-wavelength laser system, is used to evaluate the radiator bars to obtain critical values like transmittance and reflectivity. The current results and techniques will be presented on this poster. Work supported by EU FP7 grant, contract no. 227431, HadronPhysics2, and HGS-HIRe