Quantitative Phase Analysis of Challenging Samples using Neutron Powder Diffraction. Sample #4 from the CPD QPA Round Robin Revisited.

Abstract

Data from an unopened vial of the microabsorption sample #4 from the International Union of Crystallography Commission on Powder Diffraction QPA round robin were collected using a modern time-of-flight (TOF) neutron powder diffractometer. Additional considerations taken into account over and above a normal QPA were magnetic reflections from the magnetite in the sample and the contribution to the background in the high Q region of the data from thermal diffuse scattering. Data from constant-wavelength neutron and high resolution synchrotron diffractometers were analyzed for comparison. The effectiveness of the modified robust refinement weighting methodology in reducing quantification errors in constant-wavelength neutron data where magnetic reflections are ignored was examined.