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一、引言所谓液氦冷凝泵,是指一种靠低温介质(液氦)将固体表面冷却到极低温度(≤4K),使沸点高于这一温度的碰撞气体被冷凝在该低温表面上,从而产生很大抽气作用的泵。其抽气机制基本上是一种物理吸附过程。从理论上讲,这种泵具有一系列显著的特色: (1)在10~(-1)～10~(-10)帕这样一个宽的压力范围内都具有较大的抽速,而且其比抽速可接近于理论值; (2)极限真空度高,可达10~(-10)帕范围; (3)抽气基本无选择性(只有氦气除外,来自金属真空系统的氦气通常也是极其稀少的), (4)实际抽气能力大,且在理论上没有限制; (5)极清洁,真空系统不会受到泵的任何污染; (6)易于并能够完全再生;
I. INTRODUCTION The so-called liquid helium condensate pump refers to a method of cooling a solid surface to a very low temperature (≤4K) by using a low-temperature medium (liquid helium) so that collision gas having a boiling point higher than this is condensed on the low-temperature surface , Resulting in a great pumping effect of the pump. The pumping mechanism is basically a physical adsorption process. In theory, this pump has a number of salient features: (1) a large pumping speed over a wide pressure range of 10 -1 to 10 -10 Pa, and its The specific pumping speed can be close to the theoretical value; (2) the ultimate vacuum is high, up to 10 ~ (-10) Pa range; (3) the basic non-selective pumping (except helium gas from the metal vacuum helium Usually extremely rare), (4) the actual pumping capacity is large and theoretically unlimited, (5) extremely clean, the vacuum system is not contaminated by the pump, (6) is easy and can be fully regenerated,