STAR QA Board

["Van Buren, Gene" <gene@bnl.gov>]

Thanks, Ben. I confirm that I see both the highly displaced collision <z> 
position as well as a shifted BeamLine x and y intercept for runs 20072034 - 
20073028. I will also add that the Offline QA shift reported this during Run 
19 and marked it as an issue, with the following note:

'The anomalies in TPC hit plots caused by the off-center position of the
bunch-bunch intersection region along the beam line and problem with beam
"cogging". '
https://www.star.bnl.gov/devcgi/qa/QAShiftReport/issueEditor.php?iid=15019

I don't see any particular discussion of this in the ShiftLog from March 
12-13, 2019. I'm not yet sure what to make of the data quality in this group 
of runs.

Thanks,
-Gene


> On Jul 14, 2020, at 2:29 PM, Benjamin Kimelman <bkimelman@ucdavis.edu> 
> wrote:
> 
> Hi Rosi,
> 
> Great idea. I went ahead and made that plot and I'm attaching it here. The 
> VPD Vz appears to be very consistent with the TPC Vz and shows the 
> distribution shifter toward more negative values.
> 
> Ben Kimelman
> Ph.D. Candidate, Nuclear Physics Group
> UC Davis
> He/him/his
> 
> 
> On Tue, Jul 14, 2020 at 11:18 AM Rosi Reed <rosijreed@lehigh.edu> wrote:
> Hi Ben,
> 
> Even though the statistics will be low, if this is due to the beam
> conditions you should see the same shift in the vpd Vz, which could be
> a good cross-check.
> 
> Cheers,
> 
> Rosi
> 
> On Tue, Jul 14, 2020 at 2:15 PM Benjamin Kimelman via STAR-QAboard-l
> <star-qaboard-l@lists.bnl.gov> wrote:
> >
> > Hi Gene and the QA Board,
> >
> > I've been looking more through my QA and I have identified the run where 
> > the Vz distribution drops on day 72: 20072034.
> >
> > You can look at my QA plots for that run here: 
> > https://www.star.bnl.gov/protected/lfsupc/bkimel/productionQA/AuAu_19p6GeV_2019_calib/runs/AuAu_19p6GeV_run_20072034_productionQA.pdf
> >
> > The vertex does seem to be shifted more in the negative direction. It was 
> > also the first physics run of a new fill after about 12 hours of 
> > pedestals and cosmics. This makes me more inclined to believe that the 
> > shift we see in my QA in the mean Vz is due to beam conditions.
> >
> > Ben Kimelman
> > Ph.D. Candidate, Nuclear Physics Group
> > UC Davis
> > He/him/his
> > _______________________________________________
> > STAR-QAboard-l mailing list
> > STAR-QAboard-l@lists.bnl.gov
> > https://lists.bnl.gov/mailman/listinfo/star-qaboard-l
> 
> 
> 
> -- 
> Rosi Reed
> RHIC/AGS UEC member
> Associate Professor, Physics Department
> Lehigh University
> (610)758-3907
> 16 Memorial Drive East Office 406
> Bethlehem, PA 18015
> she/her/hers
> <20072034_vpd_vz.png>