Two dimensional x-ray phase imaging using single grating interferometer with embedded x-ray targets

Abstract

Using multidot metal targets embedded in a diamond substrate, we created a single-grating Talbot-Lau interferometer and used it to capture two dimensional (2D) x-ray phase images. The ensemble of these targets constitutes a tiny virtual array of x-ray source and enables x-ray phase-contrast imaging with no source or absorption grating within a 1 m source-detector distance for 8 keV x-rays. We directly resolved a dot-pattern self-image of the phase grating with 6 µm pitch by using an x-ray image detector with 24 µm pixels and obtained 2D differential-phase and dark-field images from a single-exposure. Using the 2D differential-phase images, we also obtained a phase image with no streak artifacts.

High-accuracy wavefront sensing for x-ray free electron lasers

“…Similar setups have been used to measure the wavefront of synchrotron radiation [17] and to perform imaging [18,19]. In this work we emphasize optimization for high performance of the sensor on a single-shot basis with an unattenuated full FEL beam, and its applications to systematic studies of FEL beam characteristics at different locations along the beam path.…”

Sample phase gradient and fringe phase shift in dual phase grating X-ray interferometry

“…(11) and (5) respectively. Equation (13) shows that this formula lays foundation of quantitative imaging for sample phase gradients with dual phase grating x-ray interferometry. Based on our understanding of fringe formation mechanism [18], we developed above intuitive and heuristic method to derive Eqs.…”

“…The good agreement between the theoretical values and the fringe-pattern retrieved values provide a validation of Eq. (13). For details, see text.…”

“…Apparently, the larger the ∆φ/(2πα) is, the larger the magnitude of the fringe phase shift is. Equation (13) can be used to compute the angular sensitivity of a given setup for design optimization of an interferometer. For example, Tab.…”

“…The detector just resolves the beat patterns of large periodicities, and renders other fine patterns to a constant background. Hence, different from Talbot-Lau interferometry [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], the dual phase grating interferometers directly detect interference fringes without the need of absorbing analyzer grating. This advantage brings significant radiation dose reduction as compared to Talbot-Lau interferometry.…”