Thermal Diffuse Scattering in Neutron Time-of-Flight Powder Patterns

1989 ◽  
Vol 166 ◽  
Author(s):  
Michael J. Radler
Keyword(s):  
Transition Metal ◽  
Inelastic Scattering ◽  
Diffuse Scattering ◽  
Elevated Temperatures ◽  
Time Of Flight ◽  
Significant Fraction ◽  
Thermal Diffuse Scattering ◽  
Neutron Time ◽  
Thermal Diffuse ◽  
Profile Refinement

ABSTRACTInelastic scattering from lattice phonons contributes a significant fraction of the observed Bragg intensity in time of flight neutron powder patterns of transition metal monoxides at elevated temperatures. Ignoring this thermal diffuse scattering (TDS) leads to errors in the site occupations of defects present in these materials. The intensity from one phonon TDS has been calculated as a function of time-of-flight and used to correct the measured intensities. The effect of this correction on the results of Rietveld profile refinement is discussed.

Calculation of full-pattern neutron time-of-flight (TOF) powder diffraction patterns

2017 ◽  
Vol 32 (4) ◽  
pp. 228-236 ◽  
Author(s):  
J. Faber
Keyword(s):  
Powder Diffraction ◽  
Order Approximation ◽  
Time Of Flight ◽  
Powder Diffraction File ◽  
Thermal Diffuse Scattering ◽  
Structure Information ◽  
Neutron Time ◽  
Diffraction Patterns ◽  
Thermal Diffuse ◽  
Atomic Coordinates

The ICDD has implemented an option in Powder Diffraction File (PDF)-4 products to calculate time-of-flight (TOF) neutron powder diffraction patterns using atomic coordinates and structure information (the PDF-4+ 2016 has 271 499 entries that contain atomic coordinates and structure data). The calculated pattern data are used to populate PDF data cells and entries that contain d-spaces and neutron intensities, and are also available for calculated on-the-fly fully digitized patterns. To extend this on-the-fly capability, we include size and strain effects that affect the profile shapes. For specific application to TOF neutron diffraction full pattern analyses, a method was developed for calculating a background function. This method treats incoherent scattering and a zeroth order approximation to thermal diffuse scattering. The results are compared with experimental data from SRM 640C (Si), SRM 676 (Al2O3 corundum), SRM 660C (LaB6), and NAC (Na2La3Al2F14) instrument standards. Finally, a comparison of the calculated total patterns (Bragg scattering plus background) scattering contrast between Nd2Ni2InD7.52 and Nd2Ni2InH7.52 shows the value of neutron scattering simulation for planning experiments.

A neutron-diffraction study of potassium bromide

1973 ◽  
Vol 137 (4) ◽  
Author(s):  
G. E. Bacon ◽  
D. H. Titterton ◽  
C. R. Walker
Keyword(s):  
Neutron Diffraction ◽  
Diffraction Data ◽  
Diffuse Scattering ◽  
Scattering Amplitude ◽  
Coherent Scattering ◽  
Neutron Diffraction Study ◽  
Potassium Bromide ◽  
Neutron Diffraction Data ◽  
Thermal Diffuse Scattering ◽  
Thermal Diffuse

AbstractNeutron-diffraction data have been collected from a KBr single crystal. 380 reflections were measured, reducing to 23 when averaged over equivalents. Data were corrected for extinction and thermal diffuse scattering and refinement yielded a neutron coherent scattering amplitude

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