Title :
Some studies of the optical properties of the new hemispherical PMTs from Electron Tubes Inc
Author :
Paneque, D. ; Ostankov, A. ; Jacon, P. ; Lorenz, Enno ; Lubsandorhiev, B. ; Martinez, Manuel ; Mirzoyan, R. ; Vasilje, R. ; Weinfurtne, S.
Author_Institution :
Inst. de Fisica d´´Altes Energies, Univ. Autonoma de Barcelona, Spain
Abstract :
The main optical and electrical properties of the new, fast and low gain, 6-stage hemispherical PMTs 9116A and 9117A from Electron Tubes Inc. for their use in the air Cherenkov telescope MAGIC have been studied in detail. MAGIC is a 17 m-Ø telescope to be installed in 2001 on the Canary Island of La Palma. Special emphasis of the reported PMT study is put on the discussion of the detection efficiency and the factors contributing to its absolute value and its uniformity over the photocathode. In particular the photoelectron collection efficiency and its dependence on the voltage between photocathode and first dynode have been measured. Also, the influence of the first dynode multiplication uniformity on the overall uniformity of the PMT response is discussed. The hemispherical cathode together with a specially shaped light concentrator allows increasing the effective quantum efficiency. This improvement has been measured as a function of wavelength. Aging and after pulsing rate studies have been carried out at a PMT gain of 20 k
Keywords :
Cherenkov counters; cosmic ray apparatus; gamma-ray detection; photomultipliers; 9116A; 9117A; MAGIC; air Cherenkov telescope; detection efficiency; dynode multiplication uniformity; effective quantum efficiency; optical properties; photoelectron collection efficiency; pulsing rate studies; Calibration; Cameras; Cathodes; Electron optics; Electron tubes; Extraterrestrial measurements; Physics; Telescopes; Voltage; Wavelength measurement;
Conference_Titel :
Nuclear Science Symposium Conference Record, 2000 IEEE
Conference_Location :
Lyon
Print_ISBN :
0-7803-6503-8
DOI :
10.1109/NSSMIC.2000.949277
