User name R. Michaels
Log entry time 09:49:14 on June29,2004
Entry number 127360
Followups:
keyword=Q2 measurementQ2 measurement.
Run 1199 was a spot++ check. Looked ok.
VDCs still off.
1 uA on target.
Rates:
L-arm HAPPEX detector PMT 1 = 228 kHz
L-arm HAPPEX detector PMT 2 = 358 kHz
R-arm HAPPEX detector PMT 1 = 500 kHz
R-arm HAPPEX detector PMT 2 = 160 kHz
T1 = 730 kHz
T2 = 620 kHz
T3 = 670 kHz
T4 = 520 kHz
T5 = T6 = 0
Run 1200 to log these rates.
Next, we turn down the beam current to 0.2 uA and turn on VDCs
Run 1201 for Q2 measurement
T1 = 175 kHz
T2 = 140 kHz
T3 = 155 kHz
T4 = 120 kHz
Run 1202 is a repeat Q2.
The data looked good online (detectors, tracks, etc).
Realized dithering was still on. We turn it off and do run 1203.
To some extent this "accident" (of running with dithering on)
was not bad, since we run the experiment with dithering on,
and we can verify it makes little difference (not expected to).
Run 1203 -- without dithering.
Fig 1 -- Run 1202 Q2 and missing mass.
Required a hit in HAPPEX detector (either segment) taking
into account the different gains.
The most important thing for now is the SHAPE, and NOT THE VALUE.
(Database is slightly wrong, e.g. I don't have surveyed angles).
I checked the same plots for run 1203 (dithering off).
Q2 looked the same but shifted lower
by 0.08% and 0.12% on Left, Right HRS resp. (in the noise).
FIGURE 1
