10K温区弱磁性二级高频脉管制冷机研究

Two-stage Weak Magnetic Stirling-type Pulse Tube Cryocooler Working at Temperature Around 20K

蓄冷器填充无磁不锈钢丝网,第一级使用液氮预冷,110 W输入电功下,第二级最低温度9.6 K,为国内外同类结构的最低记录。为进一步降低温度并保留弱磁特性,开展使用多孔材料吸附部分工质氦气作为蓄冷介质的研究。实验测试了活性炭在10 K温区对氦气的吸附量,表明吸附氦气后的活性炭比热已经高于此温区常规的蓄冷材料。计算了活性炭和氦气在不同频率下的热穿透深度,表明活性炭以及吸附在活性炭内部微孔中的氦气热穿透深度能够满足要求。

By using the weak magnetic st ainless st eel mesh as regenera tor material,the second-stage achieved a temperature of 9.6 K with 110 input power when the first-stage was precooled by liquid nitrogen,which is a new record for stainless steel mesh type pulse tube cryocooler.To achieve a lower temperature and retain the weak magnetic properties,the use of activated carbons (AC) with adsorbed helium as a part of the regenerator material to enhance the heat capacity of the matrix has been studied.The adsorbed helium amount by AC was tested,and it shows the specific heat capacities of the AC with adsorbed helium is close to or even exceeded than the commonly used rare-earth mat erials.The heat penetration depth of AC is large enough because of its smaller specific hea t capacity.The heat penetration depth of adsorbed helium is much larger than the size of AC microspores.