Neutron Diffraction
(PDF-4+ 2015, PDF-4/Minerals 2015)

neutron
Identification of a two phase fuel cell composition performed using the PDF-4+ program SIeve+. The experimental data are courtesy of the OPAL neutron diffractometer at the Bragg Institute ANSTO, Sydney, Australia.

In 2014, we announced our neutron diffraction analysis capability based on constant wavelength neutron diffraction. In 2015, we added the ability to analyze deuterated materials and continued to produce neutron pattern references for newly discovered materials. Major additions made to the SIeve/SIeve+ analysis programs to quantify and identify materials can be applied to neutron, electron, synchrotron, and X-ray data.

New Capability: Search and identify neutron diffraction data and quantitate by RIR

Neutron powder diffraction is a useful tool because elemental scattering contrast is quite different when compared to X-rays. The International Centre for Diffraction Data (ICDD) has calculated neutron scattering patterns for 255,295 entries in the PDF-4+ 2015. The calculations generated several indexes that are embedded in the databases to enable the rapid search and identification of materials. Neutron specific I/Ic values were calculated for use in the Reference Intensity Ratio (RIR) method for semi- quantitative analysis.  Users have the ability to specify custom experimental and instrumental parameters or use program defaults based on data from existing neutron diffraction facilities.  For constant wavelength experiments, the sample absorption cross section, the instrumental resolution, and the calculated I/Ic values are relatively constant over the thermal neutron wavelength range. Thus the calculated patterns are applicable over the range of commonly used neutron wavelengths. 

We have implemented search/match methods using Hanawalt, Fink and Long8 methods for phase identification and built dedicated tables in the PDF-4+ 2015 to accommodate these search/match methods. New display fields specific to neutron diffraction indexes can now be searched and displayed. These steps enable users to have an efficient search and identification method using neutron diffraction data input in the program SIeve+ with the PDF-4+ database.  For Release 2015, SIeve+ was modified to process constant wavelength neutron diffraction experimental data, and use neutron specific fields and indexes for identification. Automated quantitative analyses by the intelligent RIR method is performed by SIeve+.

 

ICDD User's Guide

Synchrotron Neutron User's GUide

Fast Facts on ICDD’s Neutron Diffraction Capability

Developed via an ICDD member task team of neutron diffractionists

255,295 entries calculated for neutron diffraction

Strong and long line index creation for rapid searches

I/Ic generated for neutron data for use in quantitative analysis by RIR

Instrument function wizard to simulate digital patterns based on international neutron facilities

Interfaces to SIeve+ to enable neutron data search and identification by several different algorithms

2015 Technical Presentations on Neutron Diffraction

2015 Denver X-ray Conference

Fundamentals of Neutron Diffraction (Workshop)
Organizer & Instructors:
P.S. Whitfield, Oak Ridge National Laboratory, Oak Ridge, TN, whitfieldps@ornl.gov
T.G. Fawcett, International Centre for Diffraction Data, Newtown Square, PA, fawcett@icdd.com
A. dos Santos, J.R. Bunn, Oak Ridge National Laboratory, Oak Ridge, TN
J. Faber, Faber Consulting Inc., Thornton, PA

2014 Technical Presentations on Neutron Diffraction

ICDD Workshop EPDIC 14

“Materials Characterization Capabilities Using the Powder Diffraction File™”

“New Neutron Diffraction Data Analysis Capabilities in PDF-4+” - T. G. Fawcett, ICDD, Newtown Square, PA

2014 Denver X-ray Conference

New Neutron Diffraction Data Capability in the ICDD PDF-4+ 2014 Relational Database,” Advances in X-ray Analysis, 58, 77-89, Faber, J., Crowder, C. E., Blanton, J., Kabekkodu, S. N., Blanton, T. N., Fawcett, T. G.,   Gourdon, O. (2015)

“A Powder Diffraction Database for All Radiations” (poster) - C.E. Crowder, S. Kabekkodu, J. Blanton, R. Vithayathil, V. Bosnic, D. Sagnella, K. Zhong, T. Blanton, T. Fawcett, ICDD, Newtown Square, PA