Log entry time 12:21:56 on May 20, 2009

Entry number 275052

During the weekend we made two BB MWDC threshold scans in order
to determine, how the number of reconstructed tracks and number
of hit wires changes with the set threshold. 

Here are the run numbers and set thresholds for all the
runs that we have taken:

1st scan:
=========

Run #   |   No. ev.   |  DT  | Front Th.  | Back Th.
----------------------------------------------------
2369    |    5M       | 11%  | 5.5 V      |  5.5V   
2370    |    500k     | 11%  | 6.0 V      |  6.0V
2371    |    600k     | 11%  | 6.5 V      |  6.5V
2372    |    500k     | 11%  | 7.0 V      |  7.0V

2nd scan:
=========

Run #   |   No. ev.   |  DT  | Front Th.  | Back Th.
----------------------------------------------------
2390    |    500k     |  11% | 7.5 V      |  7.5 V   
2391    |    500k     |  12% | 8.0 V      |  8.0 V   
2392    |    500k     |  11% | 8.5 V      |  8.5 V   
2393    |    500k     |  11% | 9.0 V      |  9.0 V   
2394    |    500k     |  11% | 9.5 V      |  9.5 V   
2395    |    500k     |  11% | 10.0 V     |  10.0 V   
2396    |    500k     |  11% | 6.75 V     |  6.75 V
2397    |    500k     |  11% | 6.25 V     |  6.25 V
2398    |    500k     |  11% | 5.75 V     |  5.75 V         

Results:
========

1.) First plot shows the distribution of number of found 
tracks for each event. 

2.) Second plot shows how relative number of events that
have at least one track changes with the set threshold.

3.) Third plot shows how relative number of events that
have at least one track changes with the set threshold. 
In this case I used Dougs cut on the protons:

TCut doug1 = "abs(L.gold.y)<0.03 && BB.tp.e.RA>750 && 
BB.tp.de.RA >500 && BB.tp.e.LA>750 && BB.tp.de.LA>500";  

which basically demands that particles must come out of
the target and that they must deposit enough energy in 
the paddles (this can be only protons or deuterons).

4.) The rest of the plots show how the mean number of 
wires that had at least one hit, changes with the
set threshol.  I have made plots for all 12 wire
planes and in all the plots I considered Dougs 
strict cut.
 
 




  

Number of reconstructed tracks per event

Relative number of events with tracks

Relative number of events with tracks (Dougs Cut)

Mean number of wires hit x1 and x1p

Mean number of wires hit u1 and u1p

Mean number of wires hit v1 and v1p

Mean number of wires hit x2 and x2p

Mean number of wires hit u2 and u2p

Mean number of wires hit v2 and v2p