General Meeting Summary 4/3/13
- All previous simulations were already run with small-angle beam pipe (2.5-inch diameter) and can thus be used for background estimations
- With sweep magnet on sweep away charged particles above ~300 MeV
- Simulations of trajectories for beam energies of 6.6 GeV and 11 GeV show weak dependence of backgrounds on beam energy, so can use 6.6 GeV for background studies
- Simulations show that the major source of background (~80%) comes from the target and the remainder from beam line components
- Final kinematic table includes consistency checks between Halls A and C
- Need to check sensitivity of signal and evaluate impact of background
SIDIS MOTIVATION AND KINEMATICS
- Phase space mostly overlapping with exclusive kinematics
- Calorimeter threshold or trigger assumption for exclusive should not be an issue for SIDIS
- Resolution as photon energies decrease not an issue for SIDIS since not resolving an exclusive final state.
- Coverage in pT is quite good for calorimeter at 4 m from target. However, calorimeter distance from target changes for exclusive settings, which could be limiting pT. Check if supplements are needed with calorimeter at different angles/distances for adequate coverage.
- For 10-cm target up to spectrometer central angles of 30 degrees no significant target effects.
- Standard HMS acceptance cut is +- 8%
- For a 10 cm target up to angles of 30 degrees one may treat the target as a point target
- 10-cm target preferable for good cross section - delta acceptance is easier, background also better for shorter targets
- For WACS 10-cm target ok. Angle between the two arms is ~45 degrees, so not much interference.
ITEMS FOR NEXT MEETING:
- Finalize background studies 1 MHz/block including:
- figure of radiation dose vs angle with magnet on using beam energy 6.6 GeV and 2.5" beam pipe
- maximum accepted dose for calorimeter
- DVCS/meson signal sensitivity checks
- SIDIS distance check with final DVCS/meson kinematics table
- Post figures on instrumentation on Wiki
- Based on previous proposal(s) prepare list of requests for information on technical aspects of the detector, e.g., paragraphs, figures etc. needed for the proposal instrumentation section
NEXT MEETING: THUR, 11 APRIL at 9AM (EST)