User name Moffit
Log entry time 07:45:57 on July26,2003
Entry number 106995
Followups:
- 106999 07/26/03 07:55 Moffit Re: Charge Asymmetry
- 108029 07/29/03 20:15 paschke Helicity Reversal (RHWP missing)
Attempted to do a Rotatable half-wave plate scan. Raster didn't seem to be working... so it was off during the entire scan.
Figure 1 shows the results. We typically see the charge asymmetry vary up to 6000 ppm during this type of scan. During THIS scan... I saw very very small variation (I actually had a few more data points to take... but gave up, seeing very little change).
We can't use the RHWP to zero the charge asymmetry.
Notified MCC of this problem. They'll notify the Source-OnCall.
Details of scan:
Run EvLo EvHi RHWP Angle
--------------------------------------
3637 2 6200 6000 120
"" 6600 12800 6500 130
"" 13600 19300 7500 150
3638 2 6600 8500 170
"" 7000 11500 8950 179
"" 12100 17000 8000 160
"" 17600 21900 7000 140
"" 22650 29000 6000 120
"" 29700 36400 5000 100
2640 2 7400 4000 80
"" 8100 14900 3000 60
"" 15600 21400 2000 40
"" 23200 30000 1000 20
PC pos = 7.383
PC neg = 7.518
Hall-A IA = 5
IHWP = OUT
Average current into Hall-A was about 5µA
Further analysis shows a similar curve for the bpms/bcms in the injector (100keV and 5MeV), although all 3 beams were present at the time.
FIGURE 1
