General Meeting Summary 4/3/13

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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)