Intercalibration of small-angle X-ray and neutron scattering data

Abstract

Absolute calibration forms a valuable diagnostic tool in small-angle scattering experiments and allows the parameters of a given model to be restricted to the set which reproduces the observed intensity. General methods which are available for absolute scaling of small-angle X-ray scattering (SAXS) data are reviewed along with estimates of the degree of internal consistency which may be achieved between the various standards. In order to minimize the time devoted to calibration in a given experimental program, emphasis is placed on developing a set of precalibrated strongly scattering standards for the SAXS facilities of the National Center for Small-Angle Scattering Research (Oak Ridge). Similar standards have been developed previously for calibration of small-angle neutron scattering (SANS) data. Particular attention is given to standards which can be used for either SAXS or SANS experiments where each sample has been independently calibrated for both types of radiation. These calibrations have been tested via the theoretical relationships between the two cross sections. It has been found that specimens best suited for such intercalibration purposes are a glassy carbon specimen where the scattering arises from voids in a carbon matrix and a perdeuterated polyethylene where the scattering arises from periodic arrangement of the crystalline lamellae. In only these two cases could the identical specimen be used for both the neutron and X-ray scattering experiments.

Everything SAXS: small-angle scattering pattern collection and correction

“…A discussion of the benefits and drawbacks of either have been well explained by Dreiss et al [42]. The most straightforward method is using a secondary standard such as Lupolen or calibrated glassy carbon samples [152,204], as they do not require detailed knowledge on detector behaviour and beam profiles, and scatter significantly allowing for rapid collection of sufficient intensity to perform the calibration. The scattering of these samples in absolute intensity units is determined separately, and its calibrated datafile should come with the sample [195,204].…”

A comparative study of the structure–property behavior of highly branched segmented poly(urethane urea) copolymers and their linear analogs

“…After azimuthal averaging, the raw data were corrected for detector noise, absorption, and background noise [15]. The data were then placed on an absolute scale using a type 2 glassy carbon sample 1.07 mm thick, previously calibrated at the advanced photon source in the Argonne National Laboratory, as a secondary standard [16].…”

Assessment of detector calibration materials for SANS experiments

“…They can also be used to place results on an absolute scale. This has been described in reviews by Wignall & Bates (1987), Russell et al (1988) and Glinka et al (1998).…”