(PDF-4+ 2015, PDF-4/Minerals 2015)
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+.