Cu Aerogel with Low Density, High Purity, and Oxidation Resistance for Bright X‐Ray Backlight

Abstract Cu aerogel is an ideal material as the X‐ray backlight target in laser diagnosis experiments owing to its porous structure and K‐shell X‐ray emission spectrum. However, because of their poor formability and oxidation resistance, the preparation of pure Cu aerogels with nanoscale particles and pores is still difficult. In this study, a Cu aerogel is fabricated by reducing nanoporous Cu‐based aerogels and assembling Cu nanoparticles. Numerous pores ranging from 1 to 10 nm are present in the Cu aerogel, resulting in a spongy Cu aerogel for integral heating. Meanwhile, a metal passivation process is integrated into the fabrication process to prevent the oxidation of the Cu aerogel. The prepared Cu aerogel is then applied to the Shenguang‐II facility, improving integral heating when irradiated under high‐energy laser pulse irradiation. Compared with the high‐purity Cu foil reference target, the Cu aerogel target emitted nearly 18% more X‐ray energy on the K‐shell, and the noise in the L‐shell spectrum of Cu aerogel is largely restrained. These results indicate that the Cu aerogel is beneficial for the laser diagnostic experiments and essential for the X‐ray radiography in inertial confinement fusion experiments.