Tuesday, Jul 9, 2013 11:00am EDT

From Hall A Wiki
Jump to: navigation, search

Logistic information

   Phone number:  1-866-740-1260
   Access code:   1978431#




Attendance: Wouter, Seamus, Nilanga, David A., Rupesh, Mark P.

  • Dave A.
    • 4 GEMs, provide wiggle room for inefficiencies and failures
  • Nilanga:
    • ~95% efficiency - what we have measured so far
    • GEMs need to be out of vacuum
    • Need not worry about vacuum
    • With GEMs we can have resolution of about 100 um or so.
    • Can we improve th-th_rec by using 100 um instead of 500um
  • David A./Seamus:
    • We need to be using r/dr as cuts, not th
  • Mark P.
    • The detector scans needed for Moller events, not ep
  • David A.
    • Interested in Moller asymmetries
    • Collimator motions are important
    • Maybe eps will be sensitive to small angles
  • Mark P.
    • Tolerances of positioning collimator hole
    • Does this change the distribution of millers, eps at the detector?
  • Things to do:
    • Inner/out collimator motion
    • p6. plots with GEM resolution much worse
      • If 100um GEM res reduces the diff widths, then good,

else these widths are not determined by the tracking system.

  • Seamus
    • 5m between the first and last GEMs -> Move the first/second GEMs closer to downstream GEMs
  • David A.
    • Main purpose of good resolution is to verify that we have valid tracks
    • The distributions that we have are not going to change very much with resolution, I suspect
  • Meet in a week, same time.