Analysis Meeting 1




1) All 3 BCM Calibration runs were analyzed and fit linearly
for BCM1,2 Freq. vs. Unser Current (I).  Between all the runs
there was a very small difference in the offset and gain measured.

2)  We've begun to analyze the Efficiencies for the Calorimeter,
Cerenkov, and Tracking yet we are in the midst of replaying
the newly calibrated data so results are decent but not fantastic.

3) I've inspected the kinematics for each run by comparing the 
data on the run sheet to the JPEG files for the HMS and SOS angles.
 I've found a small amount of human error in what was recorded (~2% of 
all runs).

BCM Calibrations 

There were 3 BCM Calib. runs performed for the experiment 52561, 52933, and 53218.  
The plots are the frequency of the Beam Current Monitor vs. current of the Unser monitor.  
The differences btw the BCM runs are extremely small and all fit linearly in the data.  

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Efficiencies - Preliminary

Note: We are expecting to redo these with the newly calibrated data.
These results are not to be taken seriously.

Calorimeter Efficiency

To identify only electrons and not pions are being measured, we apply the following cuts:

Ecalo/E' >0.7
Cer> 8

where Ecalo/E' is the energy recieved in the calorimeter divided by the energy
of the outgoing particle.  For electrons, we expect them to deposit all their 
energy in the Calo. such that Ecalo/E' ~ 1.
 Cer denotes the # of photoelectrons produced in the Cerenkov 
detector.  For pions, we know the # of p.e. is about zero and for 
electrons ~10 p.e. are produced.

Our formula for efficiency is then:

Eff(Calo) = Events (Ecalo/E' > 0.7 & Cer >8) / Events (Cer > 8)

The three points that are off the curve for low E' might be that way due to lack of
calibration or loss of efficiency at that momentum. 

Cerenkov Efficiency

The cuts applied here were:

Ecalo/E' > 1.05
Cer > 2

Ecalo/E' has been raised to restrict any contamination by pions where Cer has 
been lowered to hopfully include all electrons detected.

Efficiency is then:

Eff(Cer) = Events ( Cer >2 & Ecalo/E' > 1.05) / Events (Ecalo/E'>1.05)

Again we find low efficiciency at low E' which is likely due to uncalibration.

Tracking Efficiency

Eff(Tracking) = (TRG & PID & TR) / (TRG & PID)

where TRG: formed trigger, TR: found track, PID: particle id cut

 
 

 

Kinematics -Angles

The angles for most of the runs with the HMS and SOS were kept in the jpeg directory "angles".  I compared each
angle recorded in the run sheet to the what I saw on the JPEG.  There were only several significant contradictions that
I saw and corrected.  Other errors were somewhat minor and involved the person on shift not taking an angle
to a high enough accuracy.  For all runs on HMS and SOS, I'd say there was 2% that were in some error.

(An HMS sample JPEG is shown below for 10.65)

 Maintained by Jim Steinman