Log entry time 22:27:30 on April 02, 2010

Entry number 315791

Followups:

• 315801 04/02/10 23:28 R. Michaels optics run plan from Nilanga
• 316008 04/04/10 00:06 dalton Run-plan for tonight

After the optics data is taken, page Ahmed, John Wexler and Luis.

Thick lead target counting mode
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Setup for running on thick lead following the beam recovery procedure
- http://hallaweb.jlab.org/parity/prex/runinfo/How_to_recover_beam.html
- Set all 6 quartz detector HVs to -2000 V 
Take a 20 min run
Take a second 20 minute run (Analyse first run data using Ahmed's
prepared macro)

Thick lead target A_T detector position scan 2-3 uA
-------------------------------
Access to put detectors in integrating mode, remove cavity amplifiers
Move to empty target
Setup for high current running
- Turn lumis on
- VDC's off
- S1 and upper scints off
- Quartz detectors HV lowered for integrating mode
- At 5uA establish 4x4 raster (18x9 MCC) and beam position on board
- Find smallest current where FFB works for energy and position (< 3uA)
- Put thick lead in position
- Reestablish beam at 0.5 uA
- Adjust HV on A_T so that mean signal of 25000 channels
Do A_T scan as follows (take 1 minute per point)
- Establish small FFB beam
- John Wexler will control motion of A_T detector
- Put scandata point for each position and remember to scanclean
- Establish reproducibility 
-- Do Scan 1 three times.  Verify that the points fall on top of each
other (make plot and log it)
Do scans 2 and 3 twice each and verify that they agree.
Choose best Y position using scans 1-3 and do scan 4 twice.

Scan 1: Middle of X range, 
          11 points covering FULL range in Y (~5 mm apart)
Scan 2: Negative Edge of X range, 
          11 points covering FULL range in Y (~5 mm apart)
Scan 3: Positive Edge of X range, 
          11 points covering FULL range in Y (~5 mm apart)
Scan 4: Choose best Y position, 
          11 points covering FULL range in X (~5 mm apart)