Log entry time 01:46:21 on December 21, 2011

Entry number 361294

The helicity decoder has been merged into the analyzer which we setup in
the ~adaq/g2p/analyzer-1.5.22 directory. It provides 2 class named
THaG2PHelicity and THaG2PHelicityReader. The software now can decode and
predict the real helicity for each event under both high and low event rate. 

To predict helicity, the program need some events to gather the random
seed. It can not decide the real helicity when gathering seeds. So I made
a test of the seed gathering efficiency of this program:

EventRate       EventAmount        EventLossed(for gathering seed)
320Hz           100000             188
1kHz            100000             153
2kHz            100000             143
3kHz            100000             307
5.5kHz          100000             677

The amount of lossed event for gathering seed will increase with the
event rate increase. Typically it is 0.2~0.5s multiply by event rate.
Please notice that the seed gathering will only happen at the beginning
of each replay job so these event loss will only happen once under ideal
situation. But whenever there is a beam trip, the seed need to be
generated again.

Since this is a new program, it may still have bugs. I will appreciate if
you could turn on the helicity decoder when you are doing some replay
work and report me any possible errors.

Figure 1