SELF-OPERATING 80K - 150K MINIATURE J-T CRYOCOOLER

Self-operating, low-vibration 80K - 150K J-T miniature cryo-cooler for longterm space applications is proposed. This J-T cryo-cooler leveragessignificant research of low-temperature phase transformation in metallicalloys with Shape Memory. There are three group SMA's are proposed forminiature J-T cryo-cooler: (A) - Cu - based and/or Mn-based Shape MemoryAlloys (SMAs) adapted to 80K - 150K valve open/close operations (Mn-basedalloys even to lower 30K - when neon gas is applied). (B) - high-corrosionresistance Ce-based alloys which exhibit phase transformation with volumechange DV/V over 10% is recommended for valve open/close operation whenlow-purity or mixture gases are used. (C)- high-damping porous TiNi SM withsuper-elasticity is proposed to provide vibration suppression in broad rangewave band frequencies (from 20Hz to 25KHz). Miniature J-T valve utilizingCu- Mn - or Ce- based SMAs enable operation without electric motor movingparts due to reversible martensite phase transformation. The miniature J-Tcoolers utilizing SMAs present achievements of dramatically reduction overcurrently available J-T cryo-coolers as follows: (1)- orifice clogging, (2)-valve size-mass, (3) - energy consumption, and (4) -vibrations during J-Tvalve operation. J-T valve operation utilizing SMAs prevents clogging bycoolant contaminants due to great increasing throttle opening toleranceunder reversible phase transformations.