Log entry time 22:04:26 on January 15, 2009

Entry number 256271

This entry is a followup to: 256222

Followups:

• 256274 01/15/09 23:12 xqian DATAMON modification

1. Total trigger accepted, L1A, on L-HRS is counting more (~30%) causing
the negative DT in the online monitor. Total triggers accepted in the
end-run summary will be wrong too.

2. Gas Cerenkov related triggers T2 and T7 are causing significant cross
talk on T1 and T6 respectively. To test this I turned off the gas
Cerenkov and took a run to compare with the data when it was on. Note, T7
is 2.5MHz rate.

The stats are given below.

i. Run 5197(Cerenkov off) : only L1A has large difference (between BB and
LHRS). T1 and T6 are consistent on all scalers.

ii. Run 5196(Cerenkov ON): Along with L1A, T1 and T6 on various scalers
have large differences. Looks like there is some cross talk. We can fix
this by sending T2 and T7 on different BNC cables to the LHRS( It may or
may not help)

Bottom line is if we keep Cerenkov ON then we will have some significant
miscounting on L-HRS(T1 and T6). Our current off-line analysis
(BBNormAna) uses L-HRS. I am trying to modify it to use BB..lots of
things are hardcoded!!!

Figure 1

Figure 2