Commissioning and running of sPHENIX

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

Hello sPHENIXians,

This week marks the start of cryo-week #18 (out of 19 + 6 = 25).     At today's RHIC Coordination meeting, it was stated that the default plan is to run pp for 19+3 weeks per sPHENIX request, i.e., until September 16, 2024 and then just 3 weeks of AuAu, i.e., until October 7, 2024.    Under this plan there are 33 days left of pp running (!)

Extra thanks to our outgoing Period Coordinator Stefan Bathe, and welcome to our new Period Coordinator Chris Pinkenburg (picture below).     Also, welcome to our new dauntless sPHENIX shift crew (picture below).     

sPHENIX has come to the end of the high luminosity, zero crossing calorimeter jet/photon triggered running.     We will now be collecting data at +1.5 mrad and hopefully having full tracking information along with the jets and more.     Congratulations to sPHENIX for collecting over 75 pb^-1 over all z-vertices for calorimeter only data and over 11 pb^-1 within |z|<10 cm with coverage for the MVTX and INTT.    That is an excellent data set for jets and photons to analyze for physics.     

During Wednesday's Maintenance Day, we will move the ZDCs to be centered for the +1.5 mrad crossing.    Then on Thursday, C-AD will do Machine Development to ramp sPHENIX directly into +1.5 mrad crossing, rather than ramping at 0 crossing and then steering into +1.5 mrad.     Assuming the background levels are good, the plan is to stay in that configuration for the remainder of the pp running.

There has been great progress on the TPC front and a stable high voltage working point has been established with the full 111 x 111 bunches both at zero crossing and +1.5 mrad crossing.    With the 5% isobutane mixture the TPC has had no new damage to the GEMs.     This is a huge step forward for sPHENIX thanks to the hard work and perseverance of so many.   At the same time, there was new firmware loaded on Sunday morning to address dropping e-links.      

There remains a tough road ahead.    The sPHENIX goal is to collect a good sample of data with full streaming readout of the MVTX, INTT, TPC, TPOT over the next 33 days.     With the luminosities being delivered, sPHENIX could potentially sample 1.5 pb^-1 per week.    However, there appear to be data integrity / dropping issues in the INTT, TPC, and TPOT and full analysis / autopsy of data taken is incomplete.   There are daily BCO alignment meetings as it is imperative that sPHENIX verify that the data can be fully reconstructed.   Additionally the data volume with the TPC in full streaming mode is currently not consistent with stable running of the Buffer Boxes.   

Right now, sPHENIX is taking triggered-mode data with all detectors and people are working hard to check the data and tracking performance.   Tests with zero suppression are underway.    We need to push ahead and also have realistic expectations of what can be achieved in this short time.

Everyone is tired, and I apologize for being short with people at times.    sPHENIX needs to pull together and particularly improve our communication, working together, and coordinating our schedules to maximize the chances of success.   Below is a picture of where we are in the run and the remaining weeks.     Tonight I am adding a new curve for luminosity integrated with all detectors!

Below are the links to the weekly RHIC Coordination meeting presentations from sPHENIX and C-AD.  

https://indico.bnl.gov/event/20768/contributions/95441/attachments/56521/96742/sPHENIXRunCoordinator_RHICCoordinationMeeting2024_08132024.pdf

https://indico.bnl.gov/event/20768/contributions/95440/attachments/56516/96731/RHIC_Coordination_Meeting_XXVIII-1.pdf

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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