Qweak Elastic GEM Profile
Elastic electron scattering profile at Z=-528 and Z=-558, the two limits of the GEM keep out zone.
the 35 cm target is at Z = -650 cm
If 6 degrees and Z = -528-(-650)+35/2 = 139.5 cm then Y = Z \tan(6) =14.6 cm
If 6 degrees and Z = -558-(-650)-35/2 = 74.5 cm then Y = Z \tan(6) = 7.8 cm
IIf 11 degrees and Z = -528-(-650)+35/2 = 139.5 cm then Y = Z \tan(11) =27.12 cm
If 11 degrees and Z = -558-(-650)-35/2 = 74.5 cm then Y = Z \tan(11) = 14.48 cm
- GEM detector would need to span from 7.8 cm to 27.12 cm to catch elastic electrons which hit a scintillator moved 6 cm radially out from its present location.
Profiles generated by Neven using Katherine's Euclid file (Media:qweak_gw_5-dec-07.euclid.txt) representing the collimator design dated 8/8/07 from Paulo's Drawing "Hall -V QWEAK EXPERIMENT COLLIMATOR BUNKER SETUP UPSTREAM CLEANUP COLLIMATOR" # 67503-E-00021.
The previous profiles prior to this latest change in the collimator when overlayed on top of each other looked like:
The electron profile closest to the beam pipe center appears to be about 8 cm away from the beam pipe center now instead of about 7.5 cm.