General Meeting Summary 4/3/13

BACKGROUND STUDIES/DETECTOR

• 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

DVCS/MESON KINEMATICS

• 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.

HMS ACCEPTANCE

• For 10-cm target up to spectrometer central angles of 30 degrees no significant target effects.

• Standard HMS acceptance cut is +- 8%

TARGET CHOICE

• 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)