The phase imaging has a higher sensitivity for low-Z materials than conventional absorption imaging. We have developed a high-resolution X-ray phase microscope in combination with a Lau interferometer and used it for phase tomography. However, an existing method cannot avoid artifacts originating from the assumption of a two-beam interference model. In this study, we take a three-wave interference model into account to reduce the artifacts and propose a new method to attain phase tomography. In the presentation, we will demonstrate the reduction of the artifacts with the results of phase tomography.
Quantitative measurements of the phase shift of X-rays passing through a matter allow us to perform X-ray phase tomography for visualization of soft materials. Combination of an X-ray microscope and a grating interferometer is a promising approach to realize quantitative phase measurements with a microscopic spatial resolution. A Lau interferometer consisting of a source grating and a phase grating is available for this purpose with an incoherent laboratory X-ray source. We installed a Lau interferometer into a laboratory-based X-ray microscope adopting a copper rotating anode source and Fresnel zone plates (ZEISS Xradia 800 Ultra). A “twin-phase image”, which consists of positive and negative phase images overlaid with a certain separation, is generated through a fringe-scanning measurement with this microscope. A step for generating a quantitative phase image from the twin phase image should be developed to perform phase tomography. However, conventional deconvolution operations are not suitable because of artifacts and noise remained in resultant phase images. To reduce the artifacts and noise, an iterative calculation algorithm has been developed. The evaluation of the algorithm shows that the artifacts and noise are suppressed and quantitative phase images are obtained. Finally, results of phase tomography obtained for soft materials are demonstrated.
X-ray phase tomography by Talbot interferometry functions with X-rays of a broad energy band, and a pink- beam extracted by a multilayer mirror from white synchrotron radiation is used for four-dimensional X-ray phase tomography, which was developed at BL28B2, SPring-8, Japan. Polymer samples under infrared laser irradiation were observed as model experiments of laser processing. In this paper, laser ablation for a carbon-fiber reinforced polymer (CFRP) sample is reported. Thanks to the fact that the fibrous structure generates visibility (or dark-field) contrast, four-dimensional tomogram from the visibility reduction is presented. A technical effort to improve the temporal resolution from 1 s to 160 ms is also described.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.