Effect of Temperature Gradient on Gas-filling Process for Cryogenic Target with Fill-tube

The research for gas-filling technology under control was carried out for cryogenic target with fill-tube, based on temperature gradient between the fuel reservoir and target cell. The effect of temperature gradient on fuel filling processes with different size targets was studied by theoretical calculation and experiment. The results show that the influence on the initial fill pressure difference is slight with respect to different final temperatures for fuel reservoir. In other words, it is suitable for gas-filling process for target with any diameter under control by temperature gradient. One can note that the fuel injectivity is more accuracy for the wide range temperature gradient as the temperature difference reduction for fuel liquefying, with the target diameter expansion. The sensitivity within ±3 μm/K for the reservoir at the operation temperature of 75 K is quite adequate for layer thickness control purposes, with regard to the target at the diameter of 2 mm and the fuel reservoir at the volume of 1.6 mL. These results could afford an important foundation for highly accuracy of fuel injectivity of cryogenic target.