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

Producción CientíficaInterferometry 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

Producción CientíficaDiagnosing the evolution of laser-generated high energy density (HED) systems is fundamental to develop a correct understanding of the behavior of matter under extreme conditions. Talbot–Lau interferometry constitutes a promising tool, since it permits simultaneous single-shot X-ray radiography and phase-contrast imaging of dense plasmas. We present the results of an experiment at OMEGA EP that aims to probe the ablation front of a laser-irradiated foil using a Talbot–Lau X-ray interferometer. A polystyrene (CH) foil was irradiated by a laser of 133 J, 1 ns and probed with 8 keV laser-produced backlighter radiation from Cu foils driven by a short-pulse laser (153 J, 11 ps). The ablation front interferograms were processed in combination with a set of reference images obtained ex situ using phase-stepping. We managed to obtain attenuation and phase-shift images of a laser-irradiated foil for electron densities above 1e22 cm−3. These results showcase the capabilities of Talbot–Lau X-ray diagnostic methods to diagnose HED laser-generated plasmas through high-resolution imaging.The work has been supported by Research Grant No. PID2019-108764RB-I00 from the Spanish Min istry of Science and Innovatio

Industrial states and transnational exchanges of social policies: Belgium and the ILO in the interwar period

The article explores the role and impact of the International Labour Organization (ILO) as a transnational regulator of social policies. Key argument is that, first, the networks of the actors directly involved in the ILO largely determined the success or failure of the organization, and, second, the ideas, motives and strategies of these actors differed, depending on policy preferences and the political and economic reality of the day. While after World War I the locus of power for governments and employers was on the level of the national state, trade unions oriented themselves with the largest expectations towards the international level. Empirical evidence will be derived from the case of the Belgian trade unions, employers and government in the making and implementation of two ILO conventions: the Hours of Work (Industry) Convention (1919) and the Forced Labour Convention (1930). The analysis of the issues at stake in these two conventions, i.e. respectively labour in the industrialized and non-industrialized world, will throw light on the policy priorities (or non-priorities) of industrial states in the ILO during the interwar period