Implementation of Compound Refractive Lenses for Large Field of View X-Ray Phase Contrast Imaging during Hypervelocity Impact Experiments

In this study, we report a novel approach to enlarge the field of view in synchrotron-based X-Ray phase contrast imaging (XPCI) by using a two-dimensional, parabolic compound refractive lens (CRL) to generate a divergent beam upstream of the sample. Ray-tracing simulations and experimental measurements of beam size, signal intensity, and signal-to-noise ratio were conducted at the Dynamic Compression Sector (DCS) of the Advanced Photon Source (APS) to compare the nominal beamline layout against the CRL configuration. The CRL expanded the beam vertically by approximately 50% and produced a modest increase in the horizontal dimension, thus illuminating a larger portion of the sample in hypervelocity impact experiments. However, the CRL configuration also resulted in decreased beam intensity and a lower signal-to-noise ratio, reducing the effective resolution. Despite these trade-offs, the enlarged FOV the visualization of crack and failure fronts over a larger region during rod and sphere impacts into boron carbide at velocities ranging from 1.0 to 2.6 km/s. Combined with photonic Doppler velocimetry, the CRL-based XPCI provides a full field, time-resolved characterization of the dynamic response of boron carbide, offering new insights for future high strain rate materials research.