User name Lingyan
Log entry time 00:39:11 on January18,2001
Entry number 54934
keyword=dirty left gas adcFor coincidence run 1418, we are supposed to have only pi+ and protons, no electrons. Left gas cherenkov will not be fired. But the problem is as there are a lot of junk events, the adc spectra are very dirty. At current 30uA or so, the scaler rate for single PMT is about 10k(T3~1k, T4~80k), while less than 1k without beam.
The first plot is the raw adc spectrum, and the second is that after cut on T5 and good_vdc_l. The good events are just like the gold in the sands. And even worse, because they are contaminated.
I know for this kinematics, we don't need left gas to do the PID. I am just afraid that our aerogel detectors and the right gas were contaminated too.
FIGURE 1
FIGURE 2
