Study on the growth and redistribution of deuterium-deuterium layer driven by temperature gradient

We report results of crystal growth, layering of the deuterium-deuterium (D-2) layers in cylindrical cryogenic targets. For the first time, we realized the global coverage of the D-2 layer on the inner surface of the capsule through the crystal growth of D-2 ice, and the control of the temperature field without the infrared radiation, foam lining, and magnetic field. Analysis of the image of x-ray phase contrast imaging shows that the thickness of the D-2 layer is about 36.53 mu m, and the inner surface roughness is 3.23 mu m. The finite element method is applied to simulate the temperature field of the target, and the phase transition process of D-2, revealing the mechanism of D-2 covering the inner surface of the capsule. These initial experiments provide a new vision and method for exploring and achieving the pure crystal growth as well as layering of D-2 without operation of radioactive tritium.