Characterization of the solid deuterium layer in the inertial confinement fusion cryogenic target without the requirement of cryocooler deactivation

For the preparation of cryogenic fuel layer in inertial confinement fusion experiments, the vibration amplitude of cryogenic target must be reduced to the order of 1 mu m or less to ensure the fuel layer to be distinguished by the Xray phase contrast imaging system. An efficient vibration-reduction system with the Gifford-McMahon cryocooler mounted at the horizontal direction is designed, which is based on a two-stage floating thermal shielding and flexible connection. The obtained lowest temperature of the sample mount is less than 10 K, the temperature stability is within +/- 1 mK@18 K, the cooling power is greater than 500 mW, and the corresponding vibration amplitude is less than 1 mu m. With this proposed method, the X-ray phase contrast imaging of cryogenic deuterium layer can be performed successively without requirement of cryocooler deactivation. Finally, the achieved resolution of the X-ray phase contrast imaging is about 1.5 mu m while the contrast of solid-gas interface is larger than 5%, which is verified by the in-situ characterization of solidification of deuterium in the cryogenic target.

Automated summary

This article presents a method for preparing cryogenic fuel layers in inertial confinement fusion experiments. An efficient vibration-reduction system is designed to achieve vibration amplitudes of less than 1 μm, allowing the X-ray phase contrast imaging to effectively distinguish the fuel layers. Experimental results demonstrate that this method enables continuous X-ray phase contrast imaging of cryogenic deuterium layers with high resolution and contrast.