Photodetector candidates for the Tile-Hcal physics prototype.
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The high granularity cell read-out of the proposed analogue or
semi-analogue Tile HCAL calorimeter for TESLA needs photodetectors
insensitive to the large magnetic field of 4T.
Further requirements are  small sizes, good quantum efficiency for
scintillation or WLS light, large gain with low intrinsic noise,
signal stability and rather low operation voltage.
The photodetector performance is also tightly connected
with the features of the signal preamplifier at the front end.
Avalanche Photodiodes (APD's) and pixel Silicon Photomtultipliers
(SiPMs) with appropriate preamplifiers are investigated in detail as
candidates.
Results from various tests are reviewed and options for the
analogue signal read-out electronics are described.