Star-tpc-l mailing list

[Richard Witt <witt AT usna.edu>]



Dear All,

  Just found this message still in my outbox.  I’m “re”-sending it just in case it didn’t make it last week.

Cheers,

  Richard

Present: Alexei, Flemming, Tommy, Yuri, Gene, Jim, and myself

== Hardware

— TPC systems are stable and working well despite temperature fluctuations in control room, etc.

— currently on last supply of gas bottles

— order has been in since February, delivery is the problem

— remaining gas may last about 17 days

— backup plan is to find single bottles as needed if current supply runs out 

— Alexei says there are no single bottles of methane on site at BNL

— Received all parts to connect magnetometer to the system

— will start to monitor field when returns from vacation

— Gene checked humidity from dB

— getting up above 40 most days

— unusual spike in humidity that corresponds to temperature spike

== Electronics

— system continues to perform well

— temperature in the DAQ room is quite high

— some CPUs are 20 years old and may not shutdown automatically if they overheat

== Software

— conversing with ops folks on a test for gating grid during high luminosity running

— likely won’t happen this week, sPHENIX not ready for high lumi

— maybe next week, but Jeff is gone then

— Gene was asked question about abort gap cleaning

— causes large background dumps into STAR

— trade-off is beam quality degrades over fill

— alternative is to do cleaning every second

— causes a nice sawtooth pattern of SC in TPC every second

— problematic for low energy running

— Gene looked at cleaning test this past week

— could not see anything above ~.2 mm distortion as a result

— if beam intensity is increased will need to re-check, but okay for now

— SC calibrations

— Work on Runs 22 and 23

— Temple group on Run 22

— Bao Xin on Run 23, nearly complete with 1st calibration, maybe done next week

— Calibration productions for AuAu 17.3 and dAu 200 are done

— Embedding seems to have issue with respect to real data in 2019

— nothing to be done for real data

— production was started with no change to e-by-e T0

— Yuri put presentation on meeting agenda

— Yuanjing Ji noticed splitting in nHitsFit near central membrane in FXT 3.85 in embedding

— Yuri found same effect in real data for tracks associated with best primary vertex

— seems not to depend on eta

— 2nd problem noted by Tommy, broadening of vertex difference distribution using tracks only from east or only from west

— could be related to increase in beta* (~1m for collider mode, ~10m for fixed target)

— 3rd problem is the need to revisit primary vertex ranking for FXT data

— for example, does not use information about tracks with prompt hits or pileup hits, etc.

— also need to consider effect on combinatoric background for secondary vertices

— it seems that the PVZ cut is not sufficient to eliminate this problem

— plan is to introduce -35 ns offset in trigger, get estimate of target Z and use Z_w from KFCS to control jitter

— will also ask S&C to optimize primary vertex ranking for fixed target and remove PVZ cut

— should not interfere with QM2023

== AOB

— No new items for this week

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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