DVCS Trigger efficiency studies 11-Oct-2007

Sergey,

Attached is the [update excel file] that contains various trigger conditions for the dvcs_047213_pi0, dvcs_047213_10000events, and clas_047210 data sets.

The best trigger rate reduction was done by setting minimum energy thresholds at 140 and requiring a single 3x3 window to have at least 3 hits. With this the trigger rates were:

dvcs_047213_pi0 100% dvcs_047213_10000events 92.2% clas_047210 14.4%

There are 2 sheets showing the first 9 accepted, and then the first 9 rejected event images.

I then ran the 3 data sets with triggers requiring only 2 hits in the detector with thresholds over 470 (no 3x3 windows were used). With this the trigger rates became:

dvcs_047213_pi0 100% dvcs_047213_10000events 80.7% clas_047210 9.2%

There are again 2 addition sheets showing the first 9 accepted and rejected events. At first glance, the 9.2% accepted events appear to be a subset of the accepted 14.4% from above.

Let me know what you think. I still have some questions regarding what events should be accepted as PI0 events and if PI0 events are the only type of events that should be triggered on.

Thanks, Ben