Polarimeter 11 01 2010
From GlueXWiki
Preliminary evaluation of the options for polarimetry with nuclear pair production
References
- A photon beam polarimeter based on nuclear e+e- pair production in an amorphous target
- Experimental study of photon beam polarimeter based on nuclear e+e- pair production in an amorphous target
Considered Options
- Put a an e+e- detector in the beamline before the PS magnet allowing for ~2.5 m lever arm.
- Pros
- No magnetic field distortions.
- Cons
- Short lever arm.
- Detector is exposed to the photon beam.
- Pros
- Put a an e+e- detector in the beamline after the PS magnet allowing for ~4.5 m lever arm, no B-field.
- Pros
- Relatively longer lever arm.
- Cons
- Detector is exposed to the photon beam.
- Small distortion effects due to incomplete degaussing of the PS magnet.
- Pros
- Put separate e+ and e- detectors off the beamline after the PS magnet allowing for ~4.5 m lever arm, small T m.
- Pros
- Relatively longer lever arm.
- Detector not exposed to the beam
- Cons
- Magnetic field mixes different momenta and angles at the same position of the detector.
- Distortion due to the fringe fields.
- Pros