supermirror polarizer and beam simulations
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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. - PowerPoint PPT PresentationTRANSCRIPT
Supermirror polarizer and beam simulations
Christopher Crawford (UKy)
NPDGamma Collaboration Meeting
ORNL, 2010-10-15
Outline
McStas simulationsof beam profile
Characterizationof SM polarizerby Swiss Neutronics
Analysis of FP12statistics
FnPB supermirror polarizer
Fe/Si on boron float glass, no Gd
m = 3.0 critical anglen = 45 channelsr = 9.6 m radius of curvaturel = 40 cm lengthd = 0.3mm vane thickness
T=25.8% transmissionP=95.3% polarizationN=2.2£1010 n/s output flux (chopped)
simulations using McStas / ROOT ntuple
McStas Simulations
Transmission Comparison Presented at collab, mtg.2007-02-23
34% -> 26% Transmission
Changes:-Fe/Si coating-No Gd undercoat-No line of sight
Transmission
Comparison of optimal stats. vs. open pedestal
afterchopper,pedestal
Comparison of optimal stats. vs. open pedestal
afterchopper,pedestal
Polarization Comparison Presented at collab, mtg.2007-02-23
95.6%Polarization
Changes:-Fe/Si coating-No Gd undercoat-No line of sight
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
Neutron Flux vs. wavelength, position in vane
from polarimetry MRI proposal
Polarization vs. wavelength, position in vane
Neutron flux vs. Λ, Θx
Polarization vs. Λ, Θx
Beam profile before and after Smpol
before
after
horizontal vertical
Beam profile at 1st lead wall
Beam profile at 2nd lead wall
Beam profile at LH2 target
Horizontal profile vs. dist. from SMpol
Vertical profile vs. dist. from SMpol
SM polarizer characterizationby Swiss Neutronics at PSI
Specifications from SNAG
Waviness
Individual Vanes – 2
Individual Vanes – 6
Individual Vanes – 10
Individual Vanes – 14
Individual Vanes – 19
Individual Vanes – 22
Individual Vanes – 26
Individual Vanes – 26R
Reflectivity profile use in McStas simulations
McStasR+, P
Reflectivity profile use in McStas simulations
McStasR+, P
Transmission measurement at PSI
Polarization measurement at PSI
Polarization measurement data
Measurement of Flux at FP12
Americo Salas Bacci, et al.Technical Note #3
LANSCE FP12 Neutron Flux Measurement
Americo Salas Bacci,Technical Note #3
LANSCE FP12 Neutron Flux – Electronics
Fission Chamber energy spectrum
from Americo
LANSCE FP12 Neutron Flux – Electronics
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 10-7 RMS width in A
Comparison of raw counts vs. above estimate?