Grazing incidence X-ray scattering alignment using the area detector

Abstract: Grazing incidence X-ray scattering experiments are designed to achieve strong scattering signals from materials, such as molecular monolayers, island films, or thin films that are localized to the surfaces of flat substrates. Optimal signals can be achieved with precise alignment of a substrate surface with the X-ray beam. Here, we outline a simple method that utilizes the area detector, generally available on such systems, to observe reflections from the sample to determine the sample-detector distance and the motor positions corresponding to the film being parallel to and centered in the beam. Observations of the reflected and transmitted beams are used to determine the critical angle of the sample and inform ideal motor angles that will lead to scattered X-ray intensity enhancement.