User name R. Michaels
Log entry time 14:14:45 on July 6,2001
Entry number 65639
This entry is a followup to: 65635
Followups:
keyword=Re: Left arm helicity gateSome studies of the helicity gating:
1. Fig 1 shows the asymmetry in time, etc, for the 2 spectrometers using
the end-of-run scaler history data for runs 1455 - 1939 and 20455 - 20939
if run > 1/2 hour. Top left: asymmetry in time (in ppm) for L-arm is about
932 ppm on average. Top right: Ratio of charge asymmetry to time asymmetry,
peak at 1.0. A major origin of false end-of-run asymmetry is in gate time.
Bottom left: For R-arm, mostly zero time asymmetry with a small blip at 300 ppm
(usually 1 pulse too many for plus helicity). Bottom right: ratio as before.
2. Examining on a scope, we saw that the gate time on L-arm was the same for
plus and minus helicity to within 1%. I don't know how to measure more accurately
than that on a scope, nor how to adjust to < 0.1%. Does someone want to try ?
3. To improve redundancy, today I plugged in the T3 and T4 trigger from L-arm in
to normalization scaler on the R-arm (the 19th and 20th channel). Note, T1 and T2
have been read on both arms since start of experiment, except for days leading up
to June 11 (see halog 62871). So now all triggers are counted on both arms.
FIGURE 1
