using RUN 12862 to troubleshoot LTOF9B
Checked signal on scope in coinc wuith LTOF9T. With scope in avg mode,
triggering on -1.0V I see the following peak voltages:
Triggering on TOP tube: Top Peak: -1.6V Bot Peak: -0.6V
Triggering on BOT tube: Top Peak:-1.0V Bot Peak: -1.6V
tried raising LB9 voltage to -2400V and was able to reach -0.9V on bot
peak when triggering on top - tube was drawing just over 1.4mA (I think
trip is at 1.5mA?)
but count rate on scalers was half as much as adjacent tubes
looking at CFD thresholds - default setting is 31mV, will try lowering to
20.9mV (min allowable) - this made no observable difference...will return
to data taking for now, but with LB9 at -2400V since this made some
difference on the scope - redownloaded newphys_kd_SP_hibit.settings
This is starting with RUN 12863 - will run like this until the end of
shift and then check these runs tomorrow once theyare crunched.
Pete
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Pete Karpius
Graduate Research Assistant
Nuclear Physics Group
University of New Hampshire
phone: (603)978-6152
FAX: (603)862-2998
email: karpiusp@einstein.unh.edu
http://pubpages.unh.edu/~pkarpius/homepage.htm
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