Log entry time 21:27:40 on April 13, 2012

Entry number 374068

We are continuing with production data, although today has been a slog.  
A beam trip due to a fuse on the chicane magnet's safety lamp cost about 
half an hour, but returning good, centered beam after this trip was 
problematic.  In all these problems cost about 3 hours.

Production data continued in spite of high rate in the 3rd arm.  This was 
likely due to beam scraping the beam pipe somewhere, as the plots of the 
slow raster at the target were clean.  

Jixie and Chao worked for a couple hours after 18:00 to adjust the slow 
raster size and beam position to avoid the beam pipe and keep the beam 
off the target cup walls.  Fortunately, this work was done while taking 
production data, so it caused minimal delay.  We are now running with the 
beam offset to the right by 2mm to mostly avoid the pipe, while keeping 
the raster open to a total 2cm to ensure the best possible polarization.

We will continue with production through the night.  We should keep a 
close eye on the target polarization, and scale the number of events for 
each point to follow the polarization, as described in the run plan.

The target polarization is still above 30%, so we will plan for an anneal 
early tomorrow morning.  We will perform a tungsten calorimeter 
calibration at the same time, and if there is time after that before the 
anneal is done, we will have a quick access to allow a change to the 
parasitic detectors.

Moving forward through next week, we will polarize the target only 
positively to take advantage of the higher polarization that this 
configuration offers for this time-strapped energy setting.

Day Summary:
0:00-10:30: Production
10:30-11:00: Access to fix chicane trip
11:00-14:00: Restore beam, centering
14:00-now: Production with slow raster and beam position study