Log entry time 18:55:34 on October 10, 2009

Entry number 294281

Followups:

• 294302 10/10/09 21:31 V. Sulkosky How To Handle BTA for High Rates in Compton

Run Plan (Please HALOG it if you find something strange or wrong; Call RC if the problem is not resolved within 10 minutes)

1. Take production data at 100 uA! Watch the lumi widths to see if anything changes. Please check the histograms on the online data monitor with the reference ones on the shift how-to page (http://hallaweb.jlab.org/experiment/HAPPEX/opmanual/opmanual.html#HPXStartingonlineanalysis).


2. Dustin McNulty may come in to take spectrometer optics/sieve-slit runs.
   
   
3. Currently the Compton Rates are very high!
• MCC has some things they want to either check or do during swing shift:
  • possible scraping in the 3-pass separator line ("6T" region).
  • matching into the Hall A line.
  • vertical/horizontal dispersion into hall A.
• Diancheng Wang is available to check the Compton rates during swing shift. Megan Friend is on owl shift.
• Alexandre Camsonne may take low current runs for the Compton for response function purposes and DAQ tests.
• If MCC is successful in reducing the rates to an acceptancable level:
  • Take Compton data! You will need to start a new Compton run every two hours. The CODA screen to start and stop the Compton runs is in the back room.
  • If compton experts are in back room to do some tests, follow their plan.
  • If the background rates get too high, the Compton HV will trip off and you won't be able to take data. If you cannot keep it going, page Megan Friend (584-0038).


4. Change the half-wave plate state when we get to 1M good pairs. Follow the instructions for doing this and running the flipper script here: http://hallaweb.jlab.org/experiment/HAPPEX/opmanual/opmanual.html#ChangingHalfWavePlate


5. Run spot++ every couple of hours and log it. Change the prescale factor PS8 to 1 and PS1 and 2 to 99999.


6. Beam Time Accounting: accept the beam unless the Compton people say that they just cannot use it. Then record it as BNA.


7. Tomorrow around 9 am, Sasha Glamazdin will come in to do a Moller measurement.

Concerns

• Compton rates are too high, experts are aware and trying to fix it.
• If anyone must reset a magnet, they must make a halog entry stating which magnet on which arm, and what was wrong with it to require a reset. The word "tech" must appear in the subject line.
• Be sure that the prompt analysis is done for every run!
• The BTA program doesn't subtract any time to speak of for beam trips. Please manually subtract a full minute for each beam trip in the beam time accounting.
• Please write a detailed shift summary (including runs taken and any activities) and submit the BTA for each shift.
• Please make sure that the shift checklist is done once each shift.
• If you have to page or call someone for support, please do so from a counting house phone or it will be ignored!
• Keep a close eye on the lumi widths as we take data.
• Please continue to take runs even if there is no beam. These data can be used to determine pedestals. Please label these runs as having no beam.