L-PID

PID issues:

1,I cut on a small spot on PRL2vs.PRL1 to select electrons, and look at the L.cer.asum_c (blue line). 
  As you can see, there still have many low ADC channels in Cerenkov SUM, which means that from Cer, 
  there are still many Pions.

2, I did the reverse way by cutting on high ADC channels of Cer Sum (4000~5900), which indicates that 
  most of them should be electrons. However, when I cut on the electron peaks of PRL1&2, there are only
  87% of electrons

3, I look at the L.tr.beta (raw beta before timing calibration). As you can see, even I cut on PRL1.vs.PRL2
  to pick electrons, in the beta spectrum, the peak of pion is still very comparable to electron peaks.