Polarimeter Background

1
Polarimeter Background
Measure g polarization Pg from pair production

w
Need a minimum of 3 MSDs to resolve ambiguity in
position of ee- pair A fourth one fills
acceptance holes
e-
e
g
2
Polarimeter Status and Results
Plane 1
Plane 2
Detector Status
Inoperable detector

• 2 out of 4 planes operating
• perfectly (384 strips)
• Plane 2 is completely inoperable
• (256 strips)
• Big acceptance gap in plane 4 due
• to noisy strips (256 strips)

Position
Position
Plane 3
Plane 4
Analysis Status

• Obtained an angular distribution
• however there is a huge gap in
• the accpetance
• Asymmetry result is adversely
• affected by this critical
• acceptance gap

Position
Position
3
Asymmetry
g8b test
From Spring8 test
Pair Angle (w?)
Pair Angle (w?)