[Halla_pi0] (no subject)

[richard lindgren]

Hi

After we got off the phone, Khem did have some results to discuss but  
preferred to wait until next time to discuss them. Cole and I  
emphasized it was important to discuss anything he had worked on no  
matter how trivial he thought it might be.

We discussed his previous inefficiency results again  and tried to  
correlate the lower inefficiency numbers (70%) results with the new  
plots he had put up on the web -  in particular the number of hits per  
plane plot. There seems to be some crucial number that when you  
surpass it the algorithm or whatever breaks down.

I think Khem is going to try to understand why this is happening.
  Cole suggested he also look to see what the tracking routine did   
when he had two or more simultaneous proton tracks. He should also be  
able to check this.

I will look into our original background calculations for protons,  
pions and gammas that Pavel made for us. I want to see if the  
calculated proton rates are comparable to what we see in the  
scintillators. I remember doing this for neutrons and Pavel was high  
by a factor of 2 using a hydrogen target. Since this tracking  
efficiency is so rate dependent, we should try to understand the  
origin of the accidentals.


I don't understand why Khem has to vary this "resolution parameter"  
for every run in order to find the tracks efficiently. This has to be  
discussed further.

For much of the low Q2 data the tracking looks stable and about  
85-90%.  This is where we ran with low beam current.1-3 ua.
Khem is anxious to start looking at the cross section while continuing  
to troubleshoot the tracking.

I am surprised that nobody else has looked into the tracking   
efficiencies. Sure if your measuring asymmetries it is canceling out   
but maybe your losing 30-40 % of  the data!!!!

Richard