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User name V. Sulkosky
Log entry time 22:58:25 on February 23, 2009
Entry number 263013
This entry is a followup to: 263001
keyword=Re: strange s1 tdc?
The S1 TDC is performing as it should be. For the current kinematics,
there are quite a lot of junk events. The real physics rate is actually
below cosmic rate. The majority of events do not even have a track,
please see Figure 1.
In Figure 1 and 2, I plot the S1 left TDC #2 with different cuts. The
events at low TDC value are T4 events, which have a different timing than
the T3 events. If I place a cut on track variables such as the relative
momentum, then I loose almost all the remaining events. The second peak
at larger TDC values are beta < 0 particles, i.e. cosmic events. The
first peak are the real electrons in which we are interested.
The estimated electron rate at this kinematic is 0.086 Hz.
A copy of this log entry has been emailed to: jinhuang,xqian
S1 PMT # 2 with Track Cut
S1 PMT #2 with Trigger and Beta Cuts