Analysis of period and visibility of dual phase grating interferometer

Abstract

Dual phase grating interferometer may simultaneously achieve large field of view and high X-ray dose efficiency. In this paper, we developed a simple theoretical method to better understand the imaging process of the dual phase grating interferometer. The derivation process of fringe period and the optimal visibility conditions of the dual phase grating interferometer were shown in detail. Then, we theoretically proved that the fringe period and optimal visibility conditions of the dual phase grating interferometer included that of the Talbot interferometer. By comparing our experimental results with those of other researchers, we found that when the positions of phase gratings were far away from the positions where the fringe visibility was optimal, the fringe period of the dual π-phase grating interferometer was twice longer than the theoretical results under the illumination of polychromatic X-ray. And this conclusion may explain the contradictory research results of dual phase grating interferometer among different researchers.

Research on Dual-Grating Spacing Calibration Method Based on Multiple Improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise Combined with Hilbert Transform

“…However, in practical scenarios, factors such as fluctuations in energy due to laser decay over time, internal noise of photoelectric conversion components, and external disturbances caused by power supply to the vibration displacement stage can all manifest as DC drift, amplitude fluctuations, and noise spikes in the interference signals, and then lead to the generation of nonlinear signals. As a result, the accuracy of phase information extraction is diminished, leading to significant errors in grating spacing calibration [15]. Therefore, in order to enhance the precision of grating spacing calibration, suitable signal processing methods are required to extract genuine and precise phase distribution.…”

Investigations of moiré artifacts induced by flux fluctuations in x-ray dark-field imaging

“…In the field of x-ray phase imaging, x-ray grating interferometry has attracted increasing attention from the scientific community, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] since it can be implemented with conventional tube sources and detectors. [2,3] As a multi-contrast technique, x-ray grating interferometry simultaneously provides the transmission, refraction (i.e., differential phase) and dark-field images of the investigated object.…”