PREX%20Overview

1
PREX Overview
2
See Talks by Kent and Kees

• Warm septum cost issues
• Double Wein for spot size Progress both in
  justifying our need and in implemention.
• New sieve slit (More holes)

3
Q2

• Need water target(see Daves talk)
• GEMs or PWCs for high-rate tracking?
• Get 0.1 nA electronics for monitors?

VDCs have efficiency problems at high rates
4
Compton Many Talks

• IR laser fixed
• Photon detector-Good progress
• Electron Detector-Issues
• Green Laser-Issues
• Software-Data would be useful

5
Compton Issue Can we leve without electron
detector???

• Lead tungstate was too unstable.
• GSO has narrower line.
• How stable is GSO??
• Will also have integration data.
• Zero crossing of asymmetry never used in the old
  analysis.
• Redundancy is important.

6
Moller Polarimetry

• Javier in charge of new magnet
• SU is building new scintillator with more
  segmentation-parts in 6 weeks
• Collaboration must get involved for high
  precision work.

7
Linearity Measurements

• Developing possible LED test.
• ADCs being tested.
• Compton less sensitive (but pushes pulse height
  to the max)

LED tests are being used for Compton linearity
Requirements are more stringent for PREX detector
8
Horizontal Polazation

• Align collimator to minimize effect.
• Have asymmetric hole to measure transverse
  asymmetry during the experiment.

Hole
Have new detector that sees only
electrons passing though the hole.
Centered to 1 mm
Collimator
9
Horizontal Polarization
10
Monte Carlo Events
11
Binned Data
x Cut y Cut B/S FOM
All x Low y 2.9 0.27
Low x Low y 2.0 0.32
12
Sieve Slit

• Add holes

13
Test Plan During HAPPEX III

• Pulse height spectra of improved PREX detectors
• Electronics test of LUMI at high rep rate.
• LUMI backgrounds fixed?