Star-tpc-l mailing list

[Richard Witt <witt AT usna.edu>]

Present: Alexei, Gene, Jim, Zachary, Flemming, Mathias, Grazyna, Yuri, and myself

== Hardware

— things continue running well in general

— laser runs are still good with the usual caveats

— local clock overnight looks very good and with clear peaks

— question about laser tuning (or not), should we continue that way in the future?

— current method of running (no extra tuning for lasers) is acceptable

— DV measurement quality is acceptable

— half of laser runs from yesterday failed, but today all are good

— general procedure should be to allow warm-up for 5-10 minutes and then proceed

— Sector 11-8 continually trips

— could be power supply

— tried lower current limit but still doesn’t work

— will try to replace PS with spare soon

— next access will figure out how to approach the problem

— until then should leave it at 1100 - 1200 V to avoid affecting clusters in nearby regions

— lost current measurement for two days (7/27 - 7/29) due to computer being down 

— for past few days, readouts for NMR, PME, and others were down 

== Electronics

— had about 15% of iTPC dead up until this morning (went from 2 RDOs to 10)

— have not had data since the fix

— also 4 TPX sectors out

— some FEEs need to be turned off to reduce current load

— nothing else new to report

== Software

— Run 22 SC

— about a third of the way through calibration production and pass3 

— small crossover visible likely due to alignment issues

— will likely want a 4th pass with new alignment in place

— will evaluate along the way to see if further work is needed

— Production with TFG24c

— see update slides

— on average, producing ~20M events/day

— some jobs marked HOLD (likely disk space)

— difference in number of primary tracks on pDST and counting may be due to 15 fit point cut on pDST

— looking into it

— S/B ratio on K0 peaks increased by factor ~2 and widths are narrower

— number of K0 per event increases by factor ~5(!), need to study

— Update on test production with new alignment (3.2 GeV FXT)

— see slides from Mathias

— differences seen in forward/backward rapidity symmetry

— ratios differ but typically 20-30% 

— will check with spectra as a function of DCA Y 

— also, differences in number of primary tracks between productions was observed

— pDSTs were locally reproduced and the discrepancy disappeared

— may need to reproduce pDSTs

— would be interesting to see several distribution comparisons in forward and backward rapidity regions

— already have one, DCA Y, are there other significant differences?

— why do we not see same dependence in DCA X?

== AOB

— nothing else new reported 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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