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Dear collaborators,<br>
Please find H12700-H8500 comparison review attached.<br>
"Short" summary: H12700 is still better than H8500 due to the higher
photocathode quantum efficiency. The nearly uniform illumination of
pixel shows that SPE spectrum is not as good as it was anticipated.
It has more complicated structure than H8500. The structure was
described using Pavel Degtiarenko's model, and using his model's fit
results the collection efficiency was estimated for both MAPMT
types. The H8500 demonstrated higher collection efficiency than
H12700 (unexpected and rather saddening behaviour). Fortunately,
H12700 has higher photocathode quantum efficiency, and it was
determinative factor in H12700 superiority.<br>
Please note that separation of quantum and collection efficiencies
is possible <b>within model framework</b> only. However, <b>the
global efficiency</b> (decisive criteria) is model independent as
it is the fraction of events with signal over pedestal's 5 sigma
(assuming, of course, that light source is stable and constant).<br>
Any comments, suggestions or corrections are welcome!<br>
Thank you!<br>
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