Attendees: Ashot, Chao G, Chao P, Dipangkar, Eugene, Kondo, Li, Mahbub, Maxime, Nilanga, Weizhi, Xinzhan, Zhihong.


Weizhi:
1. Time dependence of the GEM efficiency at 1.1 GeV
Clusters are seen in GEM ADC peak values at different reconstructed energy.
Should be energy independent
(Smaller peak value could lead to lower efficiency )
Seems to be radius (angle) dependent, when the radius is same for ep and ee, the ADC peak distributions are same. The energy independence is also confirmed.
Similar effect seen at 2.2 GeV data.
For both energies, there is correlation between the efficiency fluctuation 
and the ADC peak values.
(Xinzhan, will check in logbook for changes that could have led to the change in the ADC peak values).
Weizhi will also check the dependence on pedestal cut for fixed cluster size (the angle dependence should go away).
There was also suggestion to do run-by-run pedestal calculation and subtraction,
and maybe also different cut for x and y strips.

2. 4 ways to extract ep/ee ratio was discussed for 2.2 GeV data set.
The most effective seems to be the one where Hycal double arm + GEM single arm is used for selecting ee. But it will have a smaller angular coverage.

All the cuts used to select ep and ee events were shown for the 2.2 GeV data set. The signal to background ratio is good for all angles, there is an small bump
at the transition region which needs to be investigated (not a big issue because only data < 2 deg will be used for this technique).
The ep / ee ratio shows smooth behavior, and seems like we can use up to 0.7 degree which corresponds to Q^2=7x10^{-4} GeV^2

Meeting cut short as we ran out of time.