Quantitative shadowgraphy and proton radiography for large intensity modulations

摘要

Shadowgraphy is a technique widely used to diagnose objects or systems in various fields in physics andengineering. In shadowgraphy, an optical beam is deflected by the object and then the intensity modulationis captured on a screen placed some distance away. However, retrieving quantitative information from theshadowgrams themselves is a challenging task because of the nonlinear nature of the process. Here, we present amethod to retrieve quantitative information from shadowgrams, based on computational geometry. This processcan also be applied to proton radiography for electric and magnetic field diagnosis in high-energy-density plasmasand has been benchmarked using a toroidal magnetic field as the object, among others. It is shown that the methodcan accurately retrieve quantitative parameters with error bars less than 10%, even when caustics are present. Themethod is also shown to be robust enough to process real experimental results with simple pre- and postprocessingtechniques. This adds a powerful tool for research in various fields in engineering and physics for both techniques.