Commissioning and running of sPHENIX

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

Hello sPHENIX Collaboration,

sPHENIX is now starting "Cryo-Week #7".   Physics running has started, and at the same time, sPHENIX is sometimes taking two steps forward and one step back (which is still progress).   Extra kudos to those working long hours over the Memorial Day Weekend.

We were running all systems (GL1, MBD, EMCal, HCal, sEPD, ZDC/SMD, MVTX, INTT, and now TPOT too!) except (TPC) at up to 15 kHz with high livetime (>90%).    It turned out that  Multi-Event Buffering  introduces a potential busy logic issue that is being addressed, so that was turned off this past weekend.    The rare event triggers, photon and jet triggers, are now running in coincidence with MBDNS>=1 and we have seen initial versions of the photon turn on curves.     To maintain decent livetime, the minimum bias MBDNS>=1 was prescaled back.   The MVTX is  often being  taken out of  data taking as logging rates fluctuate on and off and lock  up errors  are common, both of which are being addressed.   Continued improvements in the OnlineMonitoring have enabled shift crews and experts to work well together for physics data taking -- though right now with low uptime.

The TPC group has had another major push to rework the resistor chains and done a  first beam steering in and out of collision data taking.    Right now there is no  "lower voltage, safe" working point as a fall back option.    The TPC group is working on a set of tests towards that goal, and  continued discussions are important to have a well coordinated effort.    Zero suppression / firmware results are being tested, which show that this is not quite ready for prime time.   Also, the electronics are showing numerous instabilities that need to be ironed out for physics running.     Continued issues with dew point and worries about condensation are plaguing us.

As I said, two steps forward, one back.    Very nice updates on the status of each subsystem are being shown  at  the Collaboration  meeting this week..

On a very positive note, C-AD has figured out the emittance issue and is back to 111x111 bunches and expects significant increases in luminosity  in the next week.    Polarization has also been an issue - on the positive side the sPHENIX group now sees a clear indication of neutron asymmetry.

Below are the sPHENIX slides shown at the weekly RHIC Coordination Meeting (by Hugo).

https://indico.bnl.gov/event/20768/contributions/92259/attachments/54812/93775/sPHENIXRunCoordinator_RHICCoordinationMeeting_20240528.pdf

sPHENIX welcomes a new, intrepid shift crew (pictured below) and continuing Period Coordinator Hugo (pictured below).   

Stay connected.    Call into the Daily Shift Change Meetings (SCM) at 3:30 pm ET -- details below.

https://bnl.zoomgov.com/j/1614645041?pwd=bmE4STBRZk5tVVVUUC8zRnQxSlFyQT09

https://drive.google.com/drive/folders/1isP7lZPovnRTfLxBQVAuC64Cz_djisbO

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        
|| WEB:      http://spot.colorado.edu/~naglej 
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