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Archived Messages for CLAS_PHOTON@cebaf.gov: Re: miscellaneous
Re: miscellaneous
Elton Smith (elton@jlab.org)
Fri, 17 Apr 1998 13:15:41 -0400 (EDT)
> Date: Fri, 17 Apr 1998 16:41:30 +0200
> From: marchand@phnx7.saclay.cea.fr (C Marchand)
> To: elton@cebaf.gov
> Subject: miscellaneous
>
> Hi Elton,
>
> few things I forgot or forgot to tell you before I left:
>
>
> 1/ When I was in the Hall with Dave Kashy, I put in its original location the small Tagger
dumpscintillator that I displaced one night for background measurements. But I am pretty sure I
> forgot to put back HV on these two guys (manual HV power supply in the tagger rack, far right
> on the floor).
>
> 2/ When we plugged in the MOR signal directly in the scalers for g5 (without going
> through the Photon logic), we did the same for the Start counter. I hope the two cables are
> of the same length, if not the timing you check upstairs is not anymore the timing at
> the trigger level. Further, the MOR vs DSD timing is now completely out of phase upstairs.
> If you are going to change MOR timing with reshaping, don't forget that MOR/DSD delays
> have to be readjusted. Discuss these issues with Eric and Thierry.
>
> By the way, there is now a reflection on the Start counter signal, because I had no 50 ohm
> terminator downstairs to plug in the fan in/fan/out in the Tagger rack.
>
> 3/We discoverd a strange connection from Start counters 5 and 6, where the (out)bar
> is used instead of (out). See with Simon what the heck is going on there.
>
> 4/trigger rates from runs 10233 to 10235 (MOR.St.TOF, ALLTOF, no prescale)
>
> If I define i=2.10-6*MOR (1st order approximation of beam current with radiator A):
>
> trigger rate (Hz)= 70. *i + 60 *i **2
>
> From that, just make your extrapolations for g1. I hope the shielding is gonna work.
>
> 5/more to come soon.
>
> Cheers,
>
> Claude.