David R. Black, Donald A. Windover, Albert Henins, James J. Filliben, James P. Cline
The National Institute of Standards and Technology (NIST) certifies a suite of Standard Reference Materials (SRMs) to address specific aspects of instrument performance of powder diffractometers. This report describes SRM 660b, the third generation of this powder diffraction SRM used primarily for determination of the Instrument Profile Function (IPF). It is certified with respect to lattice parameter. It consists of approximately 6 g LaB6 powder prepared using a 11B isotopically enriched precursor material so as to render the SRM applicable to the neutron diffraction community. The microstructure of the LaB6 powder was engineered to produce a crystallite size above that where size broadening is typically observed and to minimize the crystallographic defects that lead to strain broadening. A NIST built diffractometer, incorporating many advanced design features, was used to certify the lattice parameter of the LaB6 powder. Both Type A, statistical, and Type B, systematic, errors have been assigned to yield a certified value for the lattice parameter of a = 0.415691(8) nm at 22.5 ˚C.
certification, diffractometer, lattice parameter, standard reference material, X-ray diffraction