Absolute calibration of small-angle scattering (SAS) intensity data (in units of differential cross-section per unit sample volume per unit solid angle) is essential for many important aspects of quantitative SAS analysis, such as obtaining the number density, volume fraction, and the specific surface area of the scatterers. It also enables scattering data from different instruments to be combined, and even can be useful to detect the existence of artifacts in the experimental data. Different primary or secondary calibration methods are available. Glassy carbon has been selected sometimes as an intensity calibration standard because it exhibits a suitable scattering intensity as well as being stable. Here we review the spatial homogeneity and temporal stability of one type of commercially available glassy carbon that is being used as an intensity calibration standard at a number of small-angle scattering facilities. We demonstrate that glassy carbon is sufficiently homogeneous and stable during routine use that it may be relied upon as a suitable standard for absolute intensity calibration of small-angle scattering data.
Citation: Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science
Pub Type: Journals
Small-angle X-ray scattering, small-angle neutron scattering, intensity calibration standard, microstructure characterization