User name paschke
Log entry time 15:32:16 on June19,2004
Entry number 126328
keyword=PITA scan Run 2283, new PC voltages, IHWP IN
For IHWP insertion (the first one since the spot move) I did a quick
PITA scan. Well, I did two, but there was no beam for all but
one point in the first one (Run 2282, which is just junk).
Dithering OFF, Charge Feedback OFF. IA cell to 5V.
*** Moved RHWP to 6500 ***
I put the PC voltages to the PC voltages which I _think_ represent
the best circular polarization from the PC (I had trouble figuring
out from previous log entries if this was correct).
Delta Pos Neg
300 8.837 1.752
200 7.170 3.419
100 5.504 5.085
0 3.837 6.752
-100 2.170 8.419
The slope was 13.24 ppm/Volt, and the offset at 0V was 65 ppm. From
this, I set new PC voltages:
For IHWP=IN, RHWP=6500 => PC Pos = 3.755, PC Neg = 6.834
To back out of the calibration, I turned feedback and dithering
back on. Early results from Run 2284 suggest the IA cell is working
harder than it should, so I need to modify the PC voltages again after