Complete tests of 2000 Hamamatsu R7525HA phototubes for the CMS-HF Forward Calorimeter

Approximately 2000 PMTs will be used to detect the Cherenkov light generated in quartz fibers embedded 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.