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    User name Kai

    Log entry time 09:56:28 on November 13, 2009

    Entry number 299503


    keyword=nonunderstandable GC spec in a T7 gas cherenkov run

    In run #4984, #25428, I prescale T1(s1&&s2) and T7(GC) both to be 1K rate, and prescale out other triggers.

    Fig1 is right arm, Fig2 is left arm. Three colors are:

    black: T->Draw("R.cer.asum_p>>T7trigger(2000,0,2000)","(D.evtypebits & 0x80) == 0x80");

    red: T->Draw("R.cer.asum_p>>TDC_GC(2000,0,2000)","R.pv.t_cor[66]>-400 && R.pv.t_cor[66]<1000");

    blue: T->Draw("R.cer.asum_p>>TDC_veto(2000,0,2000)","R.pv.t_cor[64]>-400 && R.pv.t_cor[64]<1000");

    1. The T7 should be exactly a same fanout as the GC going to the PVDIS daq. However, the black is different from blue in right arm. In left arm, it's OK. But both has huge peak at low channels which means the discriminator doesn't work as what we expect is. 2. Red is GC cut, and blue is GC&&T1. In theory, it shouldn't vary much at high current.

    I'll look the timing diff of them later.

    A copy of this log entry has been emailed to: xiaochao, rom, rsubedi

    Figure 1

    Figure 2