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一、引言在我们研制的超导转变测量装置需要测量氦沸点(4.2K)以下温度的超导转变时,采用了对恒温器内小液池里的液氦进行抽空减压降温的方法,这种方法可使低温液体的温度控制在正常沸点至三相点之问。我们用它作为测量2K以上超导转变温度的冷浴的方法。不过,单纯用此方法,会发现:被减压液池内,随着减压泵速率和环境温度等的变化液氦温度将大幅度波动。为此,通常采用对液池内加热或用固体导热平衡等方法控制液池内液氦的蒸发
I. INTRODUCTION In the superconducting transition measuring device we developed to measure the superconducting transition temperature below the boiling point of helium (4.2K), a method of evacuating and decompressing the liquid helium in a small liquid tank in the thermostat is adopted The method allows the temperature of the cryogenic liquid to be controlled from the normal boiling point to the triple point. We use it as a method of measuring a cold bath with a superconducting transition temperature above 2K. However, simply using this method, you will find: the decompression liquid pool, with the pressure pump speed and ambient temperature changes, liquid helium temperature will fluctuate significantly. To this end, usually used to heat the liquid pool or solid heat balance method to control liquid pool liquid helium evaporation