Star-tpc-l mailing list

[Richard Witt <witt AT usna.edu>]

Present: Alexei, Jim, Yuri, Tommy, Frank, Richard T., and myself

== Hardware

— small laser issue likely due to crew tuning

— expecting thunderstorm this weekend, we’ll see how the system handles it

— most of week was devoted to ToF

— Yuri requested check of sensors 

— Alexei has it on the list of things to do

— so far sensors have not detected any measurable movement of TPC

— drift velocity calculation failed for a block of runs

— last night only one run failed

— failures seem to come in blocks (crew procedure related?) 

== Electronics

— seems to be a continuing problem with RDOs

— usually about 10-12 have a problem

— typically they get repaired cyclically 

— significant number were still out this morning (another lost about an hour ago)

== Software

— Humidity 

— dehumidifier added (turned-on) in mid-August

— observed an anti-correlation (decrease in field cage current with increase in humidity)

— July 30th shows sharpe jump after power shutdown at STAR (dehumidifiers stopped)

— in that specific case, the field cage currents show an increase

— typically, as long as humidity stays below 47%, field cage currents are not significantly impacted

— Run 22 SC

— Plots from EMC calibration folks show nice convergence of N+/N- vs. 1/p from different fills compared with past test production

— significant improvement

— waiting on alignment to include last few dozen fills

— will do a pass 4 in the meantime (on remaining fills), needs about a week + 10 days

— will do pass 5 once alignment in place

— overall a 3-5 week timescale until Run 22 SC is considered done

— 2021 Full Field

— differences in O+O FF and RFF

— associated with 1 mrad rotation of TPC

— correction was included in dB

— no motion has been observed with Alexei’s sensors

— TFG24c

— test production chi^2 and primary vertex issues observed by UCD group

— work ongoing

— TFG24d

— some fixes with error calculations, particularly for outer sector 

— K0 in P24ia, TFG24c, and TFG24d

— can see pull effects (1-2%), error calculation

— pulls in FXT vs collider do not show differences in simulation but do in real data

— tried vertex reconstruction with KFParticle

— see split vertex reco in FXT (at 2 m, separated in x and y)

— may be vertex from Au on target and another from proton on target

— need to confirm

— after upgrade of cvmfs machine, exported code does not run on rcas nodes 

— thought to be due to extended instruction set 

— looking for flag to exclude extended instruction set since races nodes do not support them

== AOB

— appear to be, in Run 24, some ripple on the power lines at 0.1 Hz (noticed by Jamie)

— seems to affect beams at that time scale 

— may lead to SC effects on that time scale

— weekly reservation needs to be updated in Drupal

Best Regards,

  Richard

Sent from my iPad

-- 
"Education is the most powerful weapon which you can use to change
the world."

--Nelson Mandela

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 Richard Witt, Professor of Physics     Phone (USNA): 410-293-6675
    United States Naval Academy         Email: witt AT usna.edu
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