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Available on CMS information server CMS NOTE 2004/019 30 July 2004

Summary: Available on CMS information server CMS NOTE 2004/019
30 July 2004
Complete Tests of 2000 Hamamatsu R7525HA
Phototubes for the CMS-HF Forward Calorimeter
U. Akgun, A.S. Ayan, P. Bruecken, F. Duru, A. Mestvirishvilli, M. Miller, Y. Onel, I. Schmidt
University of Iowa, Iowa City, IA52245, USA
Bogazici University, Istanbul, Turkey
Approximately 2000 PMTs will be used to detect the Cherenkov light generated in quartz fibers em-
bedded in the CMS-HF Forward Calorimeter. The Hamamatsu R7525HA PMT was chosen for this
purpose. We measured the transit time, transit time spread, pulse width, rise time, anode dark current,
and relative gain for each tube in the test station at the University of Iowa. Life-time, gain versus high
voltage, and single photoelectron spectrum measurements were also done on a small sample of PMTs.
All the tubes were tested to verify that they conform to the HF requirements.
1 Introduction
The Compact Muon Solenoid (CMS) Experiment at the Large Hadron Collider (LHC) at the European Particle
Physics Laboratory CERN is equipped with a forward calorimeter (HF) that uses almost 2000 phototubes to read
out Cherenkov light from quartz fibers. The Hamamatsu R7525HA PMT has been chosen for this purpose[1]. It is
crucial to understand the performance of these PMTs in order to optimize the operation of the HF Calorimeter. De-


Source: Akgun, Ugur - Department of Physics and Astronomy, University of Iowa


Collections: Physics