Log entry time 03:37:39 on January 29, 2009

Entry number 258182

In production run#5667, 10 PMTs of BB cherenkov in beam line side were
turned off. So the T2 rate 
went down to 3350Hz, which is less than 18% of the rates with 20 PMT on
in the same luminosity.
I also looked at electron examples from different trig(T2 or T6) in
different PMTs. In few pmts I
even found 6 times more good electrons in T2 than T6(see the following
plots.) which are better than 
what I ever see in high luminosity run. As the rates of T2 and T6 were
same after prescale, I would say there were 6 times more electrons in T2
than in T6. By the way, I also fit the number of photon electrons in
PMT15,16,17 from T2, which have more good electrons than others, the
number of photon electrons are arount 5 to 7 (see plots).

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5