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Supermirror polarizer and beam simulations

Supermirror polarizer and beam simulations. Christopher Crawford (UKy) NPDGamma Collaboration Meeting ORNL, 2010-10-15. Outline. McStas simulations of beam profile Characterization of SM polarizer by Swiss Neutronics Analysis of FP12 statistics. FnPB supermirror polarizer.

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Supermirror polarizer and beam simulations

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  1. Supermirror polarizer and beam simulations Christopher Crawford (UKy) NPDGamma Collaboration Meeting ORNL, 2010-10-15

  2. Outline • McStas simulationsof beam profile • Characterizationof SM polarizerby Swiss Neutronics • Analysis of FP12statistics

  3. FnPB supermirror polarizer Fe/Si on boron float glass, no Gd m = 3.0 critical anglen = 45 channels r = 9.6 m radius of curvature l = 40 cm length d = 0.3mm vane thickness T=25.8% transmission P=95.3% polarization N=2.2£1010 n/s output flux (chopped) simulations using McStas / ROOT ntuple

  4. McStas Simulations

  5. Transmission Comparison Presented at collab, mtg. 2007-02-23 • 34% -> 26% • Transmission • Changes: • Fe/Si coating • No Gd undercoat • No line of sight

  6. Transmission

  7. Comparison of optimal stats. vs. open pedestal after chopper, pedestal

  8. Comparison of optimal stats. vs. open pedestal after chopper, pedestal

  9. Polarization Comparison Presented at collab, mtg. 2007-02-23 • 95.6% • Polarization • Changes: • Fe/Si coating • No Gd undercoat • No line of sight

  10. Polarization Comparison Presented at collab, mtg. 2007-02-23 • 95.6% -> 95.3% • Polarization • Changes: • Fe/Si coating • No Gd undercoat • No line of sight

  11. Neutron Flux vs. wavelength, position in vane from polarimetry MRI proposal

  12. Polarization vs. wavelength, position in vane

  13. Neutron flux vs. Λ, Θx

  14. Polarization vs. Λ, Θx

  15. Beam profile before and after Smpol before vertical horizontal after

  16. Beam profile at 1st lead wall

  17. Beam profile at 2nd lead wall

  18. Beam profile at LH2 target

  19. Horizontal profile vs. dist. from SMpol

  20. Vertical profile vs. dist. from SMpol

  21. SM polarizer characterizationby Swiss Neutronics at PSI

  22. Specifications from SNAG Waviness

  23. Individual Vanes – 2

  24. Individual Vanes – 6

  25. Individual Vanes – 10

  26. Individual Vanes – 14

  27. Individual Vanes – 19

  28. Individual Vanes – 22

  29. Individual Vanes – 26

  30. Individual Vanes – 26R

  31. Reflectivity profile use in McStas simulations McStas R+, P

  32. Reflectivity profile use in McStas simulations McStas R+, P

  33. Transmission measurement at PSI

  34. Polarization measurement at PSI

  35. Polarization measurement data

  36. Measurement of Flux at FP12 Americo Salas Bacci, et al. Technical Note #3

  37. LANSCE FP12 Neutron Flux Measurement Americo Salas Bacci, Technical Note #3

  38. LANSCE FP12 Neutron Flux – Electronics

  39. Fission Chamber energy spectrum from Americo

  40. LANSCE FP12 Neutron Flux – Electronics

  41. Comparison of statistics at LANSCE FP12 • Calculation based on: David’s estimate 2010-09-24,Americo’s note 2010-10-14, and Gericke, NIMA 611 239 (2009) • 2.68x107 n/s cm2 neutron flux at 100 μA, measured with FC • 3.5” collimator, 87.6 μA proton current • 4966 runs (after cut) x 104/20 Hz • 0.88 (air) x 0.90 (Al) x 0.88 (glass) x 0.346 (3He) transmission • 0.60 capture in LH2 x 0.3017 geom. factor • 0.53 pol. 3He x 0.989 SF eff. / (1+0.25) bkg. dilution • δA = 1.9 x 10-7 from above vs. 2.1 x 10-7RMS width in A • Comparison of raw counts vs. above estimate?

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