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Møller Polarimeter Status Update

Møller Polarimeter Status Update. Møller hardware status (detectors and targets) Systematics for SANE Plan Dave Gaskell SANE Collaboration Meeting May 30, 2008. Hall C Møller Polarimeter. Superconducting solenoid  Brute force out of plane magnetization. Scintillators  set “tune”

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Møller Polarimeter Status Update

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  1. Møller Polarimeter Status Update Møller hardware status (detectors and targets) Systematics for SANE Plan Dave Gaskell SANE Collaboration Meeting May 30, 2008

  2. Hall C Møller Polarimeter Superconducting solenoid  Brute force out of plane magnetization Scintillators  set “tune” Calorimeter  measurement

  3. Detectors Scintillators refurbished before G0 Back angle  Additional repairs before GEp One dead scintillator on left arm appeared during GEp

  4. GEp Configuration Kicker test target 4 mm foil 1 mm foil Not accessible Targets Present target configuration optimized for “high current” running  1-2 mA At 100 nA, dP/P=1% (stats) would take 2.4 hours on 4 mm target (5.9 GeV) SANE Replace 1 mm foil with 10 mm foil Replace “not accessible” with 20 mm foil and make accessible with new actuator

  5. Systematics: G0 Forward Angle Systematic error budget from G0 Forward Angle expt. dP/P = 1.32%

  6. Systematics: SANE • No “high current extrapolation” • Leakage more important dP/P < 1.5%?

  7. Systematics: SANE It is unlikely Wien will be set for maximum polarization to Hall C during SANE At 5 pass and high energy (5.9 GeV) small changes in the beam energy can impact the polarization in the Hall Example: Wien set for 80% of maximum in Hall C at 5.9 GeV  1 MeV shift in beam energy gives 2.3% change in polarization in Hall SANE? Optimum

  8. Hall C Møller during GEp Some hint of dependence of polarization on QE!

  9. Collimator Issues General philosophy: Let collimators in front of detectors determine acceptance Collimators between Q1 and Q2 “clean up” backgrounds  do not impact acceptance

  10. Collimator Issues At 5.9 GeV, collimators between Q1/Q2 come close to impinging on acceptance Collimators 6&7 can collide – may cause reproducibility problems

  11. Møller Measurement Plan Measurements desired every 2-3 days Two options: • RSS-style general procedure that anyone on shift can follow • Can make measurements anytime – whenever convenient • Results may be a little less reliable • G0 Forward-style: “small” group makes all measurements (“small”= at least 5-6 people)  Measurements need to be scheduled  More reliable polarization measurements  smaller systematic errors

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