A. Braem, E. Chesi, F. Filthaut, A. Go, C. Joram,
P. Weilhammer, P. Wicht, W. Dulinski, J. Seguinot, H. Wenzel, T. Ypsilantis
"Highly Segmented Large-Area Hybrid
Photodiodes with Bialkali Photocathodes
and Enclosed VLSI Readout Electronics"
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We report on the principles, design, fabrication, and operation of
a highly segmented, large-area hybrid photodiode, which is being
developed in the framework of the LHCb RICH project.
The device consists of a cylindrical, 127mm diameter vacuum envelope capped
with a spherical borosilicate UV-glass entrance window, with an
active-to-total-area fraction of 81%.
A fountain-focusing electron optics is used to demagnify the
image onto a 50mm diameter silicon sensor, containing 2048 pads of size
1 * 1mm2. The sensor pads are read out by 16 analogue multiplexed
readout chips enclosed in the vacuum envelope.
A large ultra-high vacuum plant for the evaporation of visible-light
transmittive bialkali (K2CsSb) photocathodes and subsequent
tube encapsulation has been built and successfully operated.
The characteristics and performance of the first HPDs have been measured
to be in full agreement with expectations.
Last modified: 25 June 1999,