[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: PMT drift
Larry Anderson writes:
>The procedure that Seamus O'Kane mentioned in his most resent posting I
>believe is a good one to follow. Placing a piece of negative in the gate
>will reduce the amount of light reaching the PMT's and prevent heating of
>the PMT dynodes and anode.
We use a black card for this purpose, shutting off all light to the PMT's
during standby periods. Is this preferable, or is there some benefit to
allowing some light to pass?
>The other area that presents problems is the shading. We are using the
>store base offsets
>that bring the Golds auto alignments back to even shading but these can have
>be changed dramatically if we run Inter Pos stock for instance.
We have also found that Ursa Gold shading can be problematic in some cases,
especially with I.P. I have just recently had success using manual shading
for the first time, eliminating the annoying Ursa "green on one side, magenta
on the other". I can't yet vouch for the repeatability of this procedure,
since I was able to go from programming to laydown without having to
autoalign (after initializing the new shading setup). Is anyone else using
this feature more extensively?
The Post Group