Ⅱ-4. Hadron Physics

RIKEN Accel. Prog. Rep. 49 (2016)

Quality assurance of PHENIX spin database for Run 15 at RHIC
S. Karthas,∗1 I. Nakagawa,∗2 and A. Deshpande∗1
The PHENIX collaboration at Brookhaven National
Laboratory takes advantage of the spin-polarized proton beam at RHIC in order to perform spin dependent
analyses. All spin relevant information are stored ina spin database accessible to the collaboration. All
the information were obtained over the 10.9 weeks ofproton-proton collisions, 5.1 weeks of proton-Gold collisions, and 1.9 weeks of proton-Aluminum collisions
at RHIC in 2015.
Due to some glitch of the accelerator control system,
there are some occasions when incorrect or null information are recorded in the database. The following
is a review and status of the quality assurance (QA)
analysis of the database of all physics runs taken in
Run 15. This QA was necessary to ensure sufficientaccuracy of the data available to the collaboration inthis database for data analyses.
The first step of the QA was to check if any of thephysics runs were missing from the database. In thefirst pass over the database there were a total of 24
missing runs. The reasons for missing runs included
the following: PHENIX magnet trips midway whilecollecting data, unsuccessful crossing shift calibrations,and issues with the data acquisition system. Of these
24 missing runs, two have been recovered and likely 13
will be recoverable since these runs were not included
as a result of an unsuccessful calibration. Those remaining, for which there was a magnet trip, will not
be used for physics analyses.
Next, it was necessary to check that each run wasassigned to the proper RHIC fill number so the spinpatterns and polarizations for each run could be crosschecked with the polarimetry group. The initial filltime is provided by the Collider Accelerator Department (CAD) as the time of beam injection and thePHENIX data acquisition system recorded the begin
and end run times. In order to verify that a run wasassigned the proper RHIC fill number, it was checkedthat the begin run time was after its associated begin
fill time and before the begin fill time for the next fill.
This method proved that all physics runs were originally assigned to the proper RHIC fill number.
The spin patterns and crossing shifts in the spin
database were checked for consistency across all runs ineach fill. The spin pattern is a record of the spin direction for each bunch of protons in the collider for a given
fill. The crossing shift is a PHENIX specific quantitythat defines the shift in the bunch number from thezeroth bunch along the bunch train. This was nec∗1∗2

essary because within a fill the crossing shift or spin
pattern should not change, but in the spin database
this occurred occasionally. The spin patterns were also
checked for consistency with the CAD database. For
inconsistencies in the crossing shift throughout a fill,
the Global Level 1 scalars were assessed to indicate
the reason for the anomaly. These scalars are scaled
down numbers of triggered events, which indicate thepresence of unfilled bunches for this QA. If no reason
was found and the bunch crossings were normal, theanomalous run(s)’s crossing shift was changed to thecrossing shift of all other runs in that fill. In addition, there were some fills that indicated an abnormal
crossing shift and were addressed on a fill-by-fill basis.
There were 7 fills for which one or more crossing shifts
were inconsistent and 5 of those have been resolved.
The remaining fills are still under investigation. Twofills had inconsistent spin patterns with CAD. These
were corrected on a run-by-run basis.
The polarization of the beam is the percentage ofeach proton bunch that is spin polarized in the designated spin direction. It is known that the polarization
gradually decays while the polarized beam is stored in
the ring for 6 to 7 h. While several physics runs aretaken during this period, assigning a simple averagepolarization of the fill to each run is not necessarily
representative of the actual polarization of the run.
We introduce ‘dynamic polarization’ to reflect the polarization decay for later runs in the fill by solving thefollowing formula:
Pdyn = Pinit + Pslope ∗ (brt − bf t)(1)

where Pdyn is the dynamic polarization, Pinit is theinitial fill polarization, Pslope is the slope of the fill polarization provided by the polarimetry group, bf t is thebegin fill time, and brt is the begin run time. The uncertainty for the dynamic polarization was calculated
by simple error propagation.
∆Pdyn = (∆Pinit )2 + (∆Pslope ∗ (brt − bf t))2 (2)The dynamic polarizations will be re-calculated once
the final polarization values are released after thoroughoffline analysis is carried out by the polarimeter group.

Department of Physics and Astronomy, State University of
New York at Stony BrookRIKEN Nishina Center- 96 -