Commissioning and running of sPHENIX

[Jamie Nagle <jamie.nagle AT colorado.edu>]

Hello sPHENIXians,

This week marks the start of cryo-week #26 (out of 19 + 6 + 2 = 27).    Only two more weeks of running left, and then some rest !

The three weeks of Au+Au commissioning (for sPHENIX and C-AD), ending at 8 am on Monday, October 21, 2024, is off to a rough start.    Unfortunately a long HV cable to one of the yellow abort-kickers died and a new cable had to  be re-run (over 500 feet).   Then a giant pencil sharpener had to be designed, built, and used to trim the cable end for connection.    Next, one of the large power supplies for the blue beam blew out multiple fuses and mosfets.    This led to significant delays with first collisions seen in sPHENIX only on Sunday evening.     Backgrounds were particularly high, with a more stable long store overnight into Monday morning.     The beam intensities are quite low as they are working around the power supply above still being unavailable (potentially for many more days).      Stochastic cooling setup is also delayed and is still in progress, with all testing of the 56 MHz pushed further back.   

Despite these challenges, the owl shift crew and experts were able to time-in the detectors (MBD, ZDC, EMCal, HCal, sEPD) and the minimum bias triggers.     An incorrect voltage configuration in the MBD was fixed this afternoon and new calibrations are being worked on by Mickey Chiu.      A 6x6 very low luminosity store (ZDC coincidence rate ~ 200 Hz) enabled data taking by all sPHENIX systems including MVTX, INTT, TPC, TPOT today -- a good first step.     This evening data was taken with a 56x56 store for the MVTX and INTT (not including the TPC) and then with only the yellow beam.     

A short summary (so far) is that there were no auto-recovery errors; however, it appears that there is an error condition that resulted in most staves dropping out after ~ 26 minutes of running in the 56x56 store.    Experts are working to determine why this did not trigger the auto-recovery.     It is important to check the offline data and engage the full set of experts tomorrow to map out the next steps forward.      The good news is the INTT and TPC data taking appears fine (with the TPC only at 6x6).     Running with the TPC tomorrow with 56x56 is the next test on that front.     sPHENIX needs to stay focussed during the limited AuAu running time and remain flexible in terms of schedule to address our commissioning goals for this running period.    

Presentations from today's RHIC Coordination meeting by sPHENIX and C-AD are linked below.   Note that these were given before the 56x56 running

https://indico.bnl.gov/event/20768/contributions/97587/attachments/57818/99278/sPHENIXRunCoordinator_RHICCoordinationMeeting2024_10082024.pdf

https://indico.bnl.gov/event/20768/contributions/97586/attachments/57789/99260/RHIC_Coordination_Meeting_XXXVI.pdf

Lastly, welcome to our next golden sPHENIX shift crew (picture below) and new Period Coordinator Akitomo Enokizono!

Extra thanks to Cameron Dean for completing his two weeks as Period Coordinator.

Sincerely,

Jamie

sPHENIX Run Coordinator 2024

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|| James L. Nagle   
|| Professor of Physics, University of Colorado Boulder

|| EMAIL:   jamie.nagle AT colorado.edu
|| SKYPE:  jamie-nagle        
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