Development of large area hybrid photodiodes for the LHCb ring imaging Cherenkov detectors

We report on the development of large area hybrid photodiodes (HPD) which are one of-the proposed photodetectors for the RICH counters of the LHCb experiment. The HPD's consist of a cylindrical vacuum envelope of 127 mm diameter capped with a spherical borosilicate W-glass entrance window. Focu...

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Bibliographic Details
Main Authors: Braem, A., Chesi, E., Dulinski, W., Filthaut, F., Go, A., Joram, C., Lion, G., Seguinot, J., Weilhammer, P., Wicht, P., Ypsilantis, T.
Format: Conference Proceeding
Language:English
Subjects:
Cathodes
Counting circuits
Detectors
Electrodes
Electron optics
Electron tubes
Focusing
Photodetectors
Photodiodes
Readout electronics
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Summary:We report on the development of large area hybrid photodiodes (HPD) which are one of-the proposed photodetectors for the RICH counters of the LHCb experiment. The HPD's consist of a cylindrical vacuum envelope of 127 mm diameter capped with a spherical borosilicate W-glass entrance window. Focusing electrodes demagnify the image on a Si detector of 50 mm diameter comprising 2048 pads with a surface of 1 mm/sup 2/ each. The analogue readout electronics is integrated in the vacuum tube. As an intermediate step a HPD with a UV sensitive CsI photocathode has been produced which allowed to verify the electron optics of the HPD. A large UHV evaporation plant for the production of HPD's with visible light transmitting bialkali photocathodes (K/sub 2/CsSb) has been built and successfully operated. The evaporation process is optimized for maximum quantum efficiency and lifetime of the photocathodes. A cold indium sealing technique developed for a minimum thermal load of the photocathode and the silicon sensor has proven to provide excellent vacuum tightness.
ISSN:1082-3654
2577-0829
DOI:10.1109/NSSMIC.1998.774819