Keywords: 
• 小丸靶 /
• 氢液滴 /
• 超冷 /
• 结晶

Abstract: Because of the existence of supercooling in a droplet formation chamber,the hydrogen micro-spheres are still in liquid phase even though their temperature is lower than the triple-point temperature.This may cause the droplets to shatter in the vacuum injection capillary.Based on the knowledge about supercooling of liquid hydrogen,we have done a thermodynamic simulation of the droplets in the droplet formation chamber,and theoretically suggested the optimal working conditions under which the droplets will most properly nucleate to solid pellets.The suggested working conditions are that the helium-gas pressure and the hydrogen vapor pressure in the droplet formation chamber are kept as low as possible,and thedroplet formation chamber should be no-less than 6 cm in the length.