title: Designing the phase grating for Talbot-Lau phase-contrast imaging systems: a simulation and experiment study.
abstract: The performance of a Talbot-Lau interferometer depends to a great extent on its visibility. This means, to obtain high quality phase-contrast and dark-field images a high visibility is mandatory. Several parameters influence the visibility of such a system, like for example the x-ray spectrum, the inter-grating distances or the parameters of the three gratings. In this multidimensional space, wave field simulations help to find the optimal combination of the grating specifications to construct a setup with a high visibility while retaining a fixed angular sensitivity. In this work we specifically analyzed the influence of the G1 grating duty cycle in simulations and experiments. We show that there is a lot of room for improvement by varying the duty cycle of the phase-shifting grating G1. As a result, by employing a third-integer duty cycle we can increase the visibility to up to 53 % in a laboratory setup with a polychromatic spectrum. The achieved visibility is more than two times higher compared to the result with a standard-type setup. This visibility gain allows a dose reduction by a factor of 5 preserving the same image quality.
authors.forename: Jens
authors.initials: J
authors.lastname: Rieger
authors.forename: Pascal
authors.initials: P
authors.lastname: Meyer
authors.forename: Georg
authors.initials: G
authors.lastname: Pelzer
authors.forename: Thomas
authors.initials: T
authors.lastname: Weber
authors.forename: Thilo
authors.initials: T
authors.lastname: Michel
authors.forename: Jürgen
authors.initials: J
authors.lastname: Mohr
authors.forename: Gisela
authors.initials: G
authors.lastname: Anton