Hi,
I am very amazed about the change in asymmetry results too. By the way,
there is not much difference in cross section (Q2 evolution of rates) and
the data rate (events/C).
Anyhow, I think the data taken today is very usable. Those in last two
days are probably usable too with more carefull analysis and maybe
corrections.
I did not want to generate any contraversy, only want to state this
problem I see on shifts and in analysis so we watch out for it in future
and in analysis.
Seems the problem went away, I m sure work by the beam crew makes a lot
of difference.
Chi
On Wed, 25 Aug 2004, zwart wrote:
> Chi,
> I am not sure if this makes a difference, but I think the state of the
> accelerator changed quite a bit last night. Dave retuned the linac and
> really improved the injection efficiency markedly (at least a factor 2).
> We know large injection losses aren't good for various systems: WC, cell
> wall etc. We (Dan and Brian) are preparing an EPICS injection efficiency
> monitor i.e. a measure of the integrated charge through the injection
> line/charge stored in the ring. It might be useful to try to correlate
> this number with the target performance, wc trip rates etc......
> I was amazed at how quietly the chambers ran. I think I had only one
> trip all last night!
>
>
> TZ
>
>
> Chi Zhang wrote:
> > Hi
> >
> > todays data, 10377-10384 10386-10389 10391 look much better than last two
> > days, in parrallel kinematics, Non-zero asymmetries are established
> > even with the little statistics accumulated so far:
> >
> > Q2 A(today) 1.7kC A(22nd-23rd) 6.6kC
> > 0.15 -0.11+-0.07 -0.009+-0.032
> > 0.20 -0.27+-0.15 -0.064+-0.059
> >
> > Pzz today looks nice at arround 0.70+-0.16.
> >
> > Chi
> >
> > On Wed, 25 Aug 2004, Townsend Zwart wrote:
> >
> >
> >>Brian,
> >>It would be useful to dig up the history of the current and voltage of
> >>the holding fields (long + trans) over the last two days. Thanks,
> >>
> >> TZ
> >>
> >>Chi Zhang wrote:
> >>
> >>
> >>>Hi, Just for record.
> >>>
> >>>in the last two days of D2 running, spin angle seemed to have drifted
> >>>to below 30 degrees. in fact could be very close to 20 degrees judging
> >>
> >>>from ed elastic asymmetries. the sympton is that asymmetries in Parallel
> >>
> >>>kinematics almost vanish.
> >>>
> >>>I am afraid this is less than optimal for Pzz measurement, T20 and maybe
> >>>Gen.
> >>>
> >>>To Shift takers: when running ed_xs.C, you can specify the spin angle by:
> >>>root ed_xs.C #### #### spinthd=<value>. theory curves for 20, 30, 32, 35,
> >>>37, 40, 45, 47, 48, 50 degrees are built in.
> >>>
> >>>Chi
> >>>
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >>
>
>
>
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