User name R. Michaels
Log entry time 02:46:20 on December 17,1999
Entry number 31251
This entry is a followup to: 31234
keyword=T4 problem -- partly resolved
The T4 anomaly was partly understood and is no longer seen.
I found that a certain program (whose name goes unmentioned,
nobody knows about it except me) which is used to read back
the MLU leaves it in "Transparent" mode always. This is wrong !
First MLU should be in "strobe" mode. This mistake (of mine) causes
the ratio of T4/T3 to be ~1. I had probably used this code to check
trigger between runs 1331 and 1342 when the trigger appears to
have gone bad for no apparent reason (e.g. no big momentum change).
What is still not explained is why for run 1349, for example, all
the T4 looked like T3. This night, I cannot reproduce this effect.
At present for several runs (1371 - 1375) all T4 look normal.
They are exclusive of T3. (Also T1,T2 look ok.) Problem gone.
Things to look for: 1) Scaler Ratio T4/T3 = 0.1 or less.
2) Same T2/T1. 3) Look at hit patterns.