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User name pking
Log entry time 13:34:49 on December 4,2014
Entry number 404474
keyword=DVCS cluster analysis from runs 10330 and 10332
The top part of Figure 1 (upper left) shows the DVCS calorimeter cluster sum as a function of cluster ID from run 10332, which was taken with 5uA of beam on the carbon target using the S2&Cer trigger with autovalidation on (meaning a calorimeter signal is not needed to accept the trigger). This is zoomed in on the soft_tower axis to focus on the pedestal band.
The bottom part of Figure 1 shows the projection onto the soft_tower axis.
As a starting point, a cluster threshold of 110 seems reasonable for the 100ns Calorimeter ADC gate width.
The top part of Figure 2 (upper right) shows the cluster sums from run 10333, which is a pedestal run with Calo HV off and the beam off. The isolated group of entries with a cluster sum of about 250 are the EDTM events in Calo block 15 (cluster ID 14).
In the bottom part of Figure 3, we can see two distributions in the global sum of the calorimeter plotted versus the cluster signal in cluster ID 14, with the global sum above 4700 associated with the EDTM events in Calo block 15 (cluster ID 14).
Putting a global threshold of 4700 seems reasonable to cut away the pedestal.
Figure 3 (lower right) shows the global sum distribution from run 10330. About 25% of the triggers would pass the global sum threshold of 4700.