LOW-TEMPERATURE COOLING MEDIUM, PRODUCTION THEREOF, METHOD FOR COOLING AND COOLER

摘要

PURPOSE:To obtain a new low-temperature cooling medium for use in closed loop coolers by cooling a mixed gas of liquid nitrogen and a specific fluorocarbon under pressure and liquefying the mixed gas. CONSTITUTION:The objective cooling medium obtained by cooling a mixed gas of (A) liquid nitrogen and (B) a fluorocarbon expressed by the formula CnF2n+2 (n is an integer of 2-4) under pressure and liquefying the above- mentioned mixed gas. Furthermore, a closed loop cooler has a cryostat containing a fluorocarbon as a cooling medium placed therein and a heat exchange pipe, arranged in an upper internal space of the aforementioned cryostat and led from a liquefier. A liquefied gas as a heat exchange medium is circulating through the interior of the aforementioned heat exchange pipe. A substance to be cooled is dipped in the cooling medium to carry out cooling.