Hi Doug,
Unfortunately, I did not confirm the Wire Chamber HV earlier in our shift.
Only toward the very end of it, I looked at the settings just by curiosity
since it did not trip at all even with high gas flow, twice as high BQM.
That was the time I realize it was 3700 all the time.
I decided to leave it as it was because we are running at a higher than
normal BQM values.
The shift was a busy one even without tripping considering each 250k
run takes only 15 minutes to complete and we had to search for spud CPU's
to lrn cos crunching was just bearly keeping up with the rate data were
coming in.
Chi
On Tue, 22 Jul 2003, Douglas Hasell wrote:
> Please try to operate the WC's at nominal voltages at all times. L6 has
> been giving occasional problems recently but also seems to recover on its
> own. Operating it at 3700 means that those 5 cells out of the 19 cells in
> the inner chamber, second super-layer are inefficient and tracking in this
> region may fail.
>
> If a WC box trips once or twice per run that is fine. Click on the WC on
> button on the HVGUI and continue the run. If it trips every 1-2 minutes
> then turn down the voltage until it holds and run like that for a while but
> after a while try raising the voltage back to nominal.
>
> The problem with L6 may be a loose wire which is very difficult to
> identify. But so far every time I have gone to the counting bay L6 has been
> able to hold the nominal voltage.
>
> It may be a nuisance resetting the trips and turning the detector off would
> certainly make the shifts a lot easier but ....
>
> --On Tuesday, July 22, 2003 9:01 AM -0400 Electronic Log Book
> <elog@blast05.lns.mit.edu> wrote:
>
> > Operators: mcilhany zhangchi mcilhany
> >
> >
> > did ABS SFT scan at beginning of shift.
> >
> > tried to take data with 0.2sccm but could not achieve reasonable halo
> > despite that CCR spent quite a while tuning.
> >
> > took unpol D2 data at 0.1sccm from 3:00 on while flipping ABS states and
> > beam helicity in same manner as T20 runs.
> >
> > Detectors seem to work very well. had couple of trip when beam is dumped!
> > WC L6 was constantly at 3700V. onlineGUI and WCquick.C show reasonable
> > signal to noise in WC even with 0.1 sccm flow.
> >
> >
> >
> >
> >
> >
>
>
>
> Cheers,
> Douglas
>
> 26-415 M.I.T. Tel: +1 617 258 7199
> 77 Massachusetts Avenue Fax: +1 617 258 5440
> Cambridge, MA 02139, USA E-mail: hasell@mit.edu
>
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