Energy-Dispersive Neutron-Transmission Diffraction
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Transcript of Energy-Dispersive Neutron-Transmission Diffraction
Energy-Dispersive Neutron-Transmission Diffraction (EDNTD)(An alternative for steady state source)
Pavol Mikula, NPI v.v.i. Řež
Energy-Dispersive Neutron-Transmission Diffraction
2dhklsin hkl=
hkl==2dhklDiffraction edge I() modulation
Instrumental resolutiond/d=5.7x10-4
The resolution (the sensitivity to the Bragg edge shift due to the strain) depends on several parameters:
•Thickness of the bent crystal monochromator (smaller thickness of the crystal, the resolution is higher, however, the luminosity of the instrument is lower)
•Take-off angle of the monochromator (the larger take off angle, the resolution is higher)
•The width of the slit in front of the sample
•Spatial resolution of the 1d- position sensitive detector and/or the distance between the sample and the detector
Sample thickness dependence of Ao
FWHM=5.7x10-4 rad
FWHM=12.5x10-4 rad
EDNTD examplesBragg diffraction edge of a 8 mm thick sample.
Energy-Dispersive Neutron-Transmission Diffractionlow-carbon steel 0.22% C, 0.64% Mn, 0.41% Si, 0.035% P, 0.04% S (in wt.%) Fe (321) diffraction edges
Comparison of the EDNTD with the conventional Bragg-diffraction-angle analysis technique
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110 reflection