Compton Study from Experimental Data

Purpose:

To show that method for selecting single arm compton events works on real compton data and to see if we can qualitatively see single arm compton events in production runs.


Double-Arm
Procedure for selecting compton events:

 Events in which:

1. 2 clusters in Hycal  
   
2. Timing  difference between trigger and tagger was less than 5ns (Timing cut)
   
3. Sum of the two clusters was greater than 0.5Gev (Energy cut)
   
4. (Radial cut): 4 cm< r< 34cm
   

Figure 1: Energy sum of two clusters minus reconstructed tagger energy






Figure 2: Delta phi distribution






Figure 3:  Pure Compton events after elasticity, delta phi and minimum angular separation cuts





Single-arm Compton

Used same procedure for selecting double arm Compton events with exception of:

1. Select events with 1 cluster
2. Assume all events are Compton

Figure 4: Sign of single arm compton in production run






Figure 5: Energy Ratio from production run with geometric cut


Summary:

1. Qualitatively, plot for single arm compton agrees with plots shown earlier.
2. We have good chance to single out single arm compton events, however work is needed to understand how this process can be used for the following two purposes:

•  To use this process to monitor Hycal gain
•  To monitor efficiency of whole exerimental setup