Agenda

1. Initial results with the new sieve [Vassu][1]

Attendance

David, Chandan, Vassu, Kate, Bill, James Shirk, Zuhal, KK, Nathan Shankman

Vassu provided updates using the new pattern of sieve holes. No phi offsets in any of the holes (yet). There are 12 holes, each 9 mm in diameter. In sectors 3 and 6 there is only one hole each - these are needed to assure a Moller/e-12C separation for the case of the one-pass data. This seems to work. Other sectors have two holes each at various radii. Now sampling from both foils in a given simulation. Clearly see the two-foil structure in plots of theta_reconstructed vs GEM_r for all three passes: 4 blobs (2 foils, 2 holes) seen for the sectors with 2 holes, and 2 blobs seen (one hole, 2 foils) seen for sectors 3 and 6.
KK asked that we check that the beam generator (GEANT 4 default cross sections) includes the 12C elastic form factor properly.
Since we think that the absence of certain holes at intermediate radii at certain beam energies is due to the Collar 2 acceptance, we should look for any backgrounds in the tracking data caused by showers in Collar 2. More generally, we should verify that using other events than just the primary electrons doesn't cause issues in our optics calibration procedure.

Meeting URL

Meeting ID: 972 5975 5403

Passcode: 4937