Agenda

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1. First steps towards determining if we need tilted holes. Vassu Doomra[[1]]

Attendance

Bill, Vassu, Zuhal, Kate, KK, Cip, Chandan, Brynna, David, Hanjie

(David): first look at simulation files generated by Kate and Bill, which attempt to incorporate low-energy EM processes (so we can look at low-energy photons (x-rays) at GEM plane locations). See hard cut-off of photons below 100 keV. After discussion, Ciprian suggests that one needs to disable the default for remoll for an active detector, which ignores neutral particles (non optical photons) below 0.1 MeV; need to set DetType == lowenergyneutral. Kate Bill will try this next.
(Vassu): looking at whether we need to "tilt" the holes in the sieve. With 1 cm diameter holes and 90 mm thick sieve, with 12C elastic generator. Initial results do not show significant effect of non-tilted holes... about 20% of events at the entrance of the holes appear to be lost due to slit-scattering. We need to understand whether this provides a significant "haze" of background events at the MD plane that could confused the optics reconstruction. Effect will be larger if the hole diameter is smaller, of course. With 12 mrad scattering angle, the radius of the track moves by 1.08 mm between front and back face of the sieve. Need to ask engineers if there are additional costs/difficulties with tilted holes, and to progress our optics algorithm to be study more carefully the effect of any slit scattering.
(Vassu) Some strange results with the R^2 values for polynomial regression of R_GEM vs. theta_hole for some sieve holes, to be understand.

Meeting ID 970 3027 1000

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