TIA: A forward model and analyzer for Talbot interferometry experiments of dense plasmas

Abstract

Interferometry is one of the most sensitive and successful diagnostic methods for plasmas. However, owing to the design of most common interferometric systems, the wavelengths of operation and, therefore, the range of densities and temperatures that can be probed are severely limited. Talbot–Lau interferometry offers the possibility of extending interferometry measurements to x-ray wavelengths by means of the Talbot effect. While there have been several proof-of-concept experiments showing the efficacy of this method, it is only recently that experiments to probe High Energy Density (HED) plasmas using Talbot–Lau interferometry are starting to take place. To improve these experimental designs, we present here the Talbot-Interferometry Analyzer (TIA) tool, a forward model for generating and postprocessing synthetic x-ray interferometry images from a Talbot–Lau interferometer. Although TIA can work with any two-dimensional hydrodynamic code to study plasma conditions as close to reality as possible, this software has been designed to work by default with output files from the hydrodynamic code FLASH, making the tool user-friendly and accessible to the general plasma physics community. The model has been built into a standalone app, which can be installed by anyone with access to the MATLAB runtime installer and is available upon request to the authors.

Phase imaging of irradiated foils at the OMEGA EP facility using phase-stepping X-ray Talbot–Lau deflectometry

“…The postprocessing module of the Talbot Interferometry Analysis (TIA) code [ 5 ] , named the Talbot Numerical Tool (TNT) [ 11 ] , was used to separate the different Fourier components of both the data and reference images, following the procedure described in the previous section. This tool has been developed to automatically detect the peaks corresponding to the periodicity of the fringes in the Fourier spectra of noisy images, which was fundamental to detect and analyze the low-contrast fringes in the data presented.…”

“…The Talbot effect exhibits itself in the fact that when a coherent wave is diffracted by a periodic grating, an exact replica of the grating is observed at a distance (called the Talbot length) from the grating. On top of that, at fractional distances of this length, a similar image, with different periodicity, is also produced [ 4 , 5 ] . The distances of interest are denoted as , where is an integer number called the Talbot order (even for transmission gratings, and odd for phase gratings).…”

Editorial: Preface to the 30th volume of Physics of Plasmas

“…The first paper in this new topical section appeared in the April issue, written by Gabriel P erez-Callejo and coauthors and titled "TIA: A forward model and analyzer for Talbot interferometry experiments of dense plasmas." 12 With my fellow editors, Min Chen, Igor Kaganovich, Jason Frank Myatt, Andr e Melzer, Andrei Smolyakov, Carl Sovinec, and Julia Stawarz, we are grateful to the many reviewers who provide the advice and set the standards required to elevate the significance, impact, and quality of the publications appearing in our journal.…”