Absolute calibration of small angle neutron scattering data using strong coherent scattering

Abstract
Typically, small angle neutron scattering (SANS) data is normalized to an absolute scale using secondary standards such as water, polymers, silica gels, or irradiated aluminum. Errors for this method of calibration arise when the initial determination or calculation of the standard's scattering cross-section is no longer valid due to degradation or wavelength-dependent multiple scattering or detector efficiency effects. Here we illustrate how strong coherent scattering can be used to experimentally measure the incident neutron beam intensity and thus serve as a primary absolute calibration. We show how easily this procedure is implemented using a ternary microemulsion as a strong scatterer and compare its accuracy with some other secondary standards commonly in use. We find that the procedure is consistent with the other standards and should be considered a viable alternative when normalizing SANS measurements.