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

Citation
A. Braem et al., Development of large area hybrid photodiodes for the LHCb ring imaging Cherenkov detectors, IEEE NUCL S, 46(3), 1999, pp. 365-370
Citations number
9
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Nuclear Emgineering
Journal title
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
ISSN journal
0018-9499 → ACNP
Volume
46
Issue
3
Year of publication
1999
Part
1
Pages
365 - 370
Database
ISI
SICI code
0018-9499(199906)46:3<365:DOLAHP>2.0.ZU;2-N
Abstract
We report on the development of large area hybrid photo diodes (HPD) which are one of the proposed photodetectors for the RICH counters of the LHCb ex periment. The HPD's consist of a cylindrical vacuum envelope of 127 mm diam eter capped with a spherical borosilicate UV-glass entrance window. Focusin g electrodes demagnify the image on a silicon detector of 50 mm diameter co mprising 2048 pads with a surface of 1 mm(2) each. The analogue readout ele ctronics is integrated in the vaccum tube. As an intermediate step a HPD wi th a UV sensitive CsI photocathode has been produced which allowed to verif y the electron optics of the HPD. A large UHV evaporation plant for the pro duction of HPD's with visible light transmissive bialkali photocathodes (K2 CsSb) has been built and successfully operated. The evaporation process is optimized for maximum quantum efficiency and life time of the photocathodes . A cold Indium sealing technique developed for a minimum thermal load of t he photocathode and the silicon sensor has proven to provide excellent vacu um tightness.