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["Fisyak, Yuri V" <fisyak AT bnl.gov>]

Hello, 

1. Splitting at the central membrane. I have a few plots at https://www.star.bnl.gov/~fisyak/star/Tpc/Alignment/9p8GeV_fixedTarget_2026C/ (which can be compared with what we have iwith 2019-2021 fixed target data (https://www.star.bnl.gov/~fisyak/star/Tpc/Alignment/FXT_CM_Tracks_splitting/).   The answer is that we don’t have extra splitting in p8GeV_fixedTarget_2026C/
2. The gas gain degradation. On https://www.star.bnl.gov/~fisyak/star/Tpc/Aging/SecRow3G4EY_2019_2026.png I compare gas gain for MIP with respect to expected from Bichsel in log scale (before gas gain correction) for runs from XIX to XXVI.
3. 

         I see significant gas gain reduction only after and during AuAu_2025 run (for AuAu_2025 I used only statistics obtained in Novemeber).

 

                                                             Yuri Fisyak

STAR                                           Phone: +1 631 344 3913
Brookhaven National Laboratory  Fax:    +1 631 344 4206
510A/1-161
http://www.star.bnl.gov/~fisyak       E-mail: fisyak AT bnl.gov

 

 

From: Ruan, Lijuan <ruan AT bnl.gov>
Date: Sunday, January 25, 2026 at 4:18 PM
To: Van Buren, Gene <gene AT bnl.gov>, Frank Geurts <geurts AT rice.edu>
Cc: Fisyak, Yuri V <fisyak AT bnl.gov>, Shinichi Esumi <esumi.shinichi.gn AT u.tsukuba.ac.jp>, skradhakrishnan AT lbl.gov <skradhakrishnan AT lbl.gov>
Subject: Re: Urgent request: calibration info on recent 4.5GeV runs

Hi Yuri, Gene,

 Here are the plots Nu sent to me. One corresponds to the 4.5 GeV data taken with HV = 1070, and the other to the current 4.2 GeV data with HV = 1150.

There appear to be many split/short tracks in the 4.5 GeV case. Is this a concern, or can these be corrected once final calibrations are applied?

Lijuan

From: Van Buren, Gene <gene AT bnl.gov>
Date: Sunday, January 25, 2026 at 1:15 PM
To: Frank Geurts <geurts AT rice.edu>
Cc: Fisyak, Yuri V <fisyak AT bnl.gov>, Ruan, Lijuan <ruan AT bnl.gov>, Shinichi Esumi <esumi.shinichi.gn AT u.tsukuba.ac.jp>, skradhakrishnan AT lbl.gov <skradhakrishnan AT lbl.gov>
Subject: Re: Urgent request: calibration info on recent 4.5GeV runs

> On Jan 25, 2026, at 11:26 AM, Frank Geurts <geurts AT rice.edu> wrote:
>
> Thanks Gene! Can you point me to some of the plots that I can share? Would this help in seeing more tracks cross the central membrane (and improve eTOF’s matching ratio)?
>
> -fg

Hi, Frank

These are mean signed DCAs for tracks that go to the east side of the TPC (the distortion to west side track is less sensitive) vs. BBC East scaler rate from FastOffline data.

- Blue points are from FastOffline files for which there was an old calibration left in place at the start of processing
- Black points have no SpaceCharge correction (I zeroed the database after a day of data-taking)
- Red points are runs processed after I calibrated and inserted into the database.

-Gene