Multianode photomultipliers as position-sensitive detectors of single photons

Tests of 2300 Hamamatsu multianode photomultipliers (1543 pieces of R5900-M 16 and 762 pieces of R5900-M4) have been tested on the bench in order to ev aluate their performance for use as position-sensitive photon detectors in the ring imaging Cherenkov counter of the HERA-B experiment.(1) A weak and stable source of photons has been obtained by Cherenkov radiation of electr ons from a Sr-90 source in a quartz radiator. From measurements of the coun t rate versus high voltage, optimal high-voltage values have been obtained as well as a parameter (RQE) corresponding to the relative quantum efficien cy. Distributions of the number of photomultipliers as a function of the op timal high voltage and as a function of the relative quantum efficiency are presented. The measured parameters are in good correlation with those prov ided by the manufacturer. The stability of the photomultipliers has also be en followed over two years. The observed count rate decrease is consistent with the radioactive decay of (9)0Sr. (C) 2000 Elsevier Science B.V. All ri ghts reserved.