利用氯的渗透性质，向超高真空系统中充入高纯度氯缓冲气体，可以降低离子阱中囚禁离子的运动速度，减小二级多普勒频移，增加离子的存储时间，提高线型离子阱微波频标的稳定度。实验上得到了氯气渗透的实验参数、特性以及对系统真空度的影响、实现了用温度调节精确的控制充入氯气的分压强。

It is convenient to introduce high-purity helium gas into ultra-high vacuum with the character of diffusion. By this way, it is not only cooling the velocity of ions, reducing the second-order Doppler frequency standard, consequently improving the stability of microwave frequency standard, but also achieving longer storage time of ions in the trap. Here, we present the experiment parameters, regularity of helium gas diffusion. It also shows the diffusion effect to the vacuum and has achieved temperature precisely control the helium diffusion pressure.