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User name R. Subedi
Log entry time 22:08:58 on January16,2009
Entry number 256398
This entry is a followup to: 256396
keyword=Run Coordinator Report: Jan 15 (Day) - 16 (Day), 2009
This time in a NICER format:
Jan 15 (Thu)-16 (Fri), 2009:
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Current polarity status of the spectrometers: BigBite -ve (for electron), L-HRS +ve (for Pi-plus).
Charge Accumulated Summary So Far
---------------------------------
Half Wave Plate Charge Expected (C) Charge Accumulated (C) Comment
Pi-minus Vertical IN 3.5 0.86 -
Pi-minus Vertical OUT 3.5 4.04 Done
Pi-minus Transverse IN 3.5 0.62 -
Pi-minus Transverse OUT 3.5 4.38 Done
Pi-plus Vertical IN 3.5 2.24 -
Pi-plus Vertical OUT 3.5 3.72 Done
Pi-plus Transverse IN 3.5 2.29 -
Pi-plus Transverse OUT 3.5 3.66 Done
Currently we are in Pi-plus Transverse mode with the half-wave-plate IN. We will stay with the
half-wave-plate IN state until the last of the experiment as the goal of the accumulated charge
in the half-wave-plate OUT state was already achieved.
Overall Plans
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1. Will stay at Pi-plus Transverse mode until Sunday (Jan 18).
2. Will go to Pi-plus Vertical mode on Sunday Day shift (~10:00).
3. Will do positron runs on next Thursday (Jan 22) Day/Swing and Swing/Owl(Friday) where
Day/Swing [total one shift]: BigBite +ve polarity and L-HRS +ve
Swing/Owl [total one shift]: BigBite +ve polarity and L-HRS -ve
4. Friday (Jan 23) Day: BigBite will be back to -ve polarity, L-HRS stays at -ve polarity.
5. Will do Moller measurement either on next Tuesday or Wednesday.
Jan 15, 2009 Day-Swing
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Activities
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Day:
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-Smooth production in Pi-plus Transverse mode
-Compton photon rate worse: ~2 kHz/uA, after injector tuning it becomes better: ~ 300 Hz/uA.
- RICH-acivity (A. Camsonne et. al.) to understand the high deadtime while in RICH-configuration
will continue until the next Sunday hall-access.
- Deadtime appears very high or -ve, speculating some of the L-HRS scaler channels double-pulsing
Swing:
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-Smooth production.
-4:30 PM: The software that controls the target ladder motion is found to be hosted on a
Hall B web server: http://clasweb.jlab.org/medm/HALLA/ha26/HallAGenTarg.edl which is
inaccessible from Hall A, thus no control for the target motion. After contacting
EPICS expert-on-call it comes back to normal location in half an hour.
- Target polarization: 65%
-Datamon code modified: instead of L-HRS scaler, BigBite scalers are used to calculate deadtime,
the deadtime becomes 15%.
Beamtime Accounting:
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ABU BANU BNA Comment
Day 6.02 0.75 0.62
Swing 5:34 1.28 1.38 Reason of BANU: Injector tuning, target motion software recovery.
Jan 16, 2009 Owl-Day
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Activities
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Owl:
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-Smooth production.
Day:
----
-Smooth production.
-Compton rate slightly degrades, fluctuates from 200 Hz/uA to 1000 Hz/uA.
-Gas-cherenkov pedestal becomes wider than usual, planning to take a pedestal run to correct it.
Beamtime Accounting:
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ABU BANU BNA
Owl 6.71 0.18 1.10
Day 6:64 0.43 0.92