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User name ramsay
Log entry time 08:04:48 on November 4,2002
Entry number 50902
keyword=00-08 (Owl) shift summary
00-08 (Owl) shift summary
Had a steady 25 uA essentially the whole shift.
Did charge and position scans.
Don't understand large charge asymmetry with helicity flip (pockels cell) and steering correction both off.
DETAILS:
We want to determine the calibration constants for the Charge and
position feedback .
Start Half wave plate scan to get the charge asymmetry reasonably low to start.
00:30 Start run #13631, HV on all detectors OFF. Beam current ~28 uA.
From g0beamfeedback screen: 1/2 plate=1100. IA=5.01,
Charge asym =933+-25
00:50 Run # 13632, 1/2 plate = 1600. Charge asym= +435.8+-22
01:30 Run # 13633, 1/2 plate = 2100. Charge asym= -250+-21
01:40 Run # 13634, 1/2 plate = 2600. Charge asym= +123+-19
01:45 Run # 13635, 1/2 plate = 600. Charge asym= +952+-18
02:00 Run # 13636, 1/2 plate = 850. Charge asym= +862+-30
02:10 Run # 13637, 1/2 plate = 1850. Charge asym= +251+-22
02:20 Run # 13638, 1/2 plate = 2400. Charge asym= -451+-17
02:33 Run # 13639, 1/2 plate = 2000. Charge asym= -383+-17
02:50 Run # 13640, 1/2 plate = 2000. Charge asym= -740+-16
03:08 Run # 13641, 1/2 plate = 2000. Charge asym= -432+-17
03:22 Run # 13642, 1/2 plate = 1800. Charge asym= -245+-16
03:44 Run # 13643, 1/2 plate = 1600. Charge asym= -518+-17
The asymmetries to not make sense. How can they jump from run to run
by so many sigma? Anyway, let's try to do the IA scans.
04:08 Turn OFF Pockels cell, still 32 degrees halfwave plate
04:10 Run # 13644, IA=5, asym = +243+-19
This should really be zero, with our helicity pockels cell off.
Decide to take long (15 m) run and look at charge asymmetry as a function of time to see if it really changes as much as it seems.
04:24 Run # 13645, IA=5, asym = +333+-10
Check with MCC that our slits are wide open. They are.
04:42 beam off to re-boot an IOC
04:48 Run # 13646, IA=1, asym = -186+-11
05:09 Run # 13647, IA=9, asym = +841+-9
Calibration is 128 ppm / V
05:40 Run # 13648, IA=5, asym = +255+-10
Let's start the PZT Scans, (dx, dy in nm)
06:20 Run 13649, pztX = 1, pztY = 5, dx= -7762+-182, dy= -7496+-206
06:40 Run 13650, pztX = 5, pztY = 5, dx= -2397+-186, dy= -333+-212
06:52 Run 13651, pztX = 9, pztY = 5, dx= +3048+-188, dy= +6340+-218
07:00 Run 13652, pztX = 5, pztY = 1, dx= -3805+-182, dy= -4928+-197
07:08 Run 13653, pztX = 5, pztY = 5, dx= -2695+-200, dy=-8677+-213
07:16 Run 13654, pztX = 5, pztY = 9, dx= -2030+-187, dy=+3454+-196
for slopes see log entry #6050
Set all voltages (pztX, pztY, IA) to 5V (i.e. no effect), and pockels cell OFF (no helicity flip) and check charge asymmetry.
07:29 Run 13655, pztX= pztY= IA = 5V, charge asym = +200+-11
Try turning OFF the Gun 3 pockels cell:
07:50 Run 13656, pztX= pztY= IA = 5V, charge asym = see log