Hi Doug,
This is true, but the vacuum rose in the ring when the buffer system was
turned on. LIG103 got up as high 5e-7 (although this gauge is under
suspicion at present) and LIGIT got up into the 10^-7 scale as well.
Other ring gauges also rose. The scalers which are in the log book were
logged after tuning and slit repositioning had been done. We judged that
beam conditions would not get much better until the vacuum improved. Since
we only had 3 hours and the wire chambers were mostly able to remain on,
we elected to take data with the beam that was available.
Once the buffer system was in steady-state operation, the vacuum did
improve the halo did start to diminish during this time. We may want to
revisit the initial pumpdown procedure for the buffer system.
Bill
On Tue, 30 Mar 2004, Douglas Hasell wrote:
> The BQM's should read around 100/35/40/25 for T/L/B/R and the WC
> scalers (same display) should be around 60/40 for L/R.
>
> IF THESE VALUES ARE HIGHER : turn off the WC's and ask CCR to
> re-optimise the slits and scrapper or re-tune if necessary. This is a
> fairly quick operation so don't hesitate to do it.
>
> SIMILARLY: if you notice a bad fill which has higher than average BQM's
> or scalers, phone CCR and ask for a new fill. If the new fill is also
> bad maybe they need to re-tune.
>
>
> 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
> On Mar 30, 2004, at 7:54 AM, Electronic Log Book wrote:
>
> > Operators: nikolas franklin ----
> >
> > Took runs unpol D2 6071-6074.
> > Countless WC trips, mainly L14. High BQMs, low klifetimes, see
> > previous elog entries.
> > Data taking halted at 7am for Hall opening.
> >
>
-- ********************************************************************** Wilbur A. Franklin * Phone: 617-253-9518 Bates Linear Accelerator Center * FAX: 617-253-9599 P.O. Box 846 * Email: wafrankl@mit.edu Middleton, MA 01949 * **********************************************************************
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