The unique conditions of the CMS experiment (4 T magnetic field, restricted access, high neutron radiation, and 25-ns bunch-crossings) necessitated the development of a new type of high-rate multichannel hybrid photodiode for the tile/fiber hadronic calorimeter. New complexities arose in the push toward high-rate operation, necessitating design changes in the diode structure and surface treatment. The product is now capable of high-rate operation with low crosstalk and leakage current. Lifetime studies of high-voltage behavior, total charge, and irradiation have shown that the tubes will survive the ten years of CMS running with only a few percent change in gain and manageable leakage current rise.
Bibliographical noteFunding Information:
Manuscript received November 19, 2001; revised February 1, 2002. This work was supported in part by the U.S. Department of Energy under Grant DOE/DE-FG02-94ER40823. The authors are with the Physics Department, University of Minnesota, Minneapolis, MN 55455 USA (e-mail: firstname.lastname@example.org; email@example.com). Publisher Item Identifier S 0018-9499(02)06156-7.
- Hybrid photodiode (HPD)