Last update: 30 March 1998

Project: Generate elastic scattering events from GSIM and reconstruct them in Recsis to evaluate time-based tracking quality.

Observations:

1. Electron momentum too high by 20 MeV out of 1332 MeV (1.5% systematic shift)
2. Electron theta too small by 1.2 degrees at 30 degrees
3. Electron phi angle is shifted by 2 degrees from generated value, but distribution is flat.
4. Got 7.6 MeV resolution for proton W peak
5. Earlier problems (25 MeV resolution) caused by relative timing constants (chamber-to-chamber, sector-to-sector) which are stored in map and used by Recsis. He set these to 0 in map entry #1.
6. All changes checked in to default GSIM
7. 200 micron DC resolution currently used by GSIM
8. Results are compatible with Volker's predictions, but we need to straighten out a few things: how much of the resolution is due to helium vs. air (air is used in the code); multiple scattering component of resolution vs. added DC resolution; brief systematic study needed.