Compton Meeting, June 9, 2011

Previous Meeting: Compton Meeting, June 2, 2011

Following Meeting:

Agenda

Laser

1. Updated schedule
   • Laser pre-alignment change request being written: move to early August

Analysis

1. Replay status
   • submission scripts tested and integrated in batch manager (see [1])
   • need all offline macros self-contained in svn, only what is in svn will be used in replay. Initial import done but untested.
   • --Wdconinc 16:08, 7 June 2011 (UTC)

Photon Detector

1. A tale of 2 runs - large backgrounds and their subtraction

Database

What information from the Compton parameters do we want to go into the database ?

(The book-keeping currently done in 'run_list' files can be automated by using the database)

Minutes

Attendance: Manos, Don, Juan Carlos, Mark, Vladas, Seth, Amrendra, Jeff, Wouter, Dave

• SAD schedule
  • moving survey & alignment to later, first/second week of August, messing with laser alignment earlier, change request in with Diane Napier after mess-up in unannounced scheduling meeting while Dave on vacation
  • start messing with laser on June 27
    • measure transfer function
    • new bellows, new cavity mirrors
    • machining of gimbal mounts (might be hard, has been in beam line, check with radcon)
    • put everything back before Don goes on vacation
  • September 19: re-fiducialization
  • September 30: final alignment
  • somehow vacuum should be pulled between these two dates (disappeared from schedule)
• Laser
  • new cavity mirrors, transfer function measurement with new mirrors
  • continued work on laser polarization measurement by Seth
• Photon detector
  • got approval for translation stage for Compton cone position measurement
• Analysis
  • batchman scripts work now
  • only 1TB work disk, not enough room for electron detector (no ROOT analyzer yet)
  • Dave's suggestion: copy things over to cdaq cluster while replay is running
  • full replay to tape silo, jget subset to work disk
  • changes in data acquisition should not affect replay continuity
  • some changes in ROOT tree names, will be sent out by email
• Tale of two runs
  • ELOG Photon 121
  • asymmetry changed when adding cuts
  • fixed width histograms, large effect when opening up range
  • yield for background subtraction, change in average asymmetry
  • Don/Dave will rerun scripts on larger set of runs to get uncertainty
• Electron detector
  • ELOG Electron 217
  • dependence of polarization on photo-cathode QE
  • QE also depends on beam current, so lowest QE point could have large horizontal uncertainty
  • link to wiki