I have analyzed some data from August run to define hot/dead 
channels. Data from runs 02445, 02446, 02447, 02450 and 02453 have 
been used to define hot wires. Data were taken during test of PACT 
converter with digital signal. Noise signal from photomultiplier was 
sent to shaper and used as trigger and test signal as well. Beam was 
off, HV on chambers were set to 1900V and threshold was set to 125 mV. 
So, chamber's data should comprise noise signals only. 

Noise data have been analyzed using most recent (unfinished) version 
of qod21. Data within 800ns time window are included in 
the histograms (at least Art believe it is set in qod21). Total number 
of triggers are about of 76000. So, total integration time is about 
of 0.06s. 

Also beam data from run 02456 are taken to compare with a noise data. 
Run 02456 had been taken with beam momentum of 29.8 MeV/c. HVs on the 
DCs are 1900V, threshold is 125 mV. Total number of events is 486875. 
Data within 800ns time window are included into the plots. Data had 
been analyzed immediately after the run end with of that time version 
of qod21.    

An attached file shows plots of a noise counts and beam profiles of 
"problem" DC planes where there are one or more channels showing high 
or lower than "expected" counting level.  
The noise counts and beam profile for each DC plane are put next to 
each other. Figure 1 presents data for DC3, DC4 and DC5; figure 2 shows 
data for DC8, DC9 and DC10; figure 3 shows the same histograms for DC13, 
DC14 and DC16 while figure 4 presents DC18. Rest of the planes did not 
show any irregularities. Low statistic doesn't allow to define noise 
level of wires. In any case these data should be considered rather 
qualitative than quantitative. (I found some numbers in some histograms 
are incorrect). 
Some channels look very noisy (#16 on DC8, #45 on DC10, #6 on DC16, 
#19 and #22 on DC18). Taking into account integrating time of 0.6s one 
gets noise rate of channel #16 on DC8 about of 2 kHz from left frame. 
From the right frame for the same channel one finds (excess is about 
of 800 counts, total integrating time is about of 0.39s) noise rate 
again is about 2 kHz.
Channel #5 on DC14 most likely has higher crosstalk level. 
  
Finally, figure 5 shows the "dead" channels. It was found just one 
such a plane DC21 (except planes of DC17, DC23 and DC24). No counts 
on channels 17 through 21 except channel 20, where contents is a half 
of the expected one. Most likely this is a "contact" problem. When I 
checked one of the runs from the beginning of the beam test I found 
all these channels were alive and channel 20 had some excess(10-30%?) 
over the neighbors. 

 --------------------------------------------------------
 Yuri Davydov (davydov@triumf.ca)       (604) 222-1047 ext.6198
 TRIUMF  			  FAX  (604) 222-1074
 4004 Wesbrook Mall
 Vancouver,  BC  Canada   V6T 2A3

Filename: rates.ps.gz

Filename: rates.ps

Created for the The Center for Subatomic Research E614 Project Projects Page.

Created by The CoCoBoard.