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T: Fachverband Teilchenphysik

T 30: Experimentelle Methoden der Astroteilchenphysik 1

T 30.2: Vortrag

Montag, 24. März 2014, 17:05–17:20, P7

Novel Photo Multiplier Tubes for the Cherenkov Telescope Array Project — •takeshi toyama, razmik mirzoyan, and uta menzel — Max Planck Institute for Physics ,Munich, Germany

Currently the standard light sensors for imaging atmospheric Cherenkov telescopes are the classical photo multiplier tubes that are using bialkali photo cathodes. About eight years ago we have initiated an improvement program with the Photo Multiplier Tube (PMT) manufacturers Hamamatsu (Japan), Electron Tubes Enterprises (England) and Photonis (France) for the needs of imaging atmospheric Cherenkov telescopes. As a result, after approximately 40 years of "stagnation" of the peak Quantum Efficiency (QE) on the level of 25-27%, new PMTs appeared with a peak QE of 35%. These have got the name "super-bialkali". The second significant upgrade has happened very recently, as a result of dedicated improvement program for the candidate PMT for Cherenkov Telescope Array. Photo multiplier tubes with average peak QE of approximately 40% became available. Also, the photo electron collection efficiency of the previous generation PMTs of 80-90% has been enhanced towards 95-98% for the new ones. The after-pulsing of novel PMTs has been reduced towards the level of 0.02% for the set threshold of * 4 photo electrons. We will report on the photo multiplier tube development work by the companies Electron Tubes Enterprises and Hamamatsu and show the achieved results and the current status.