Patent ID: 7295010

Claim:
A low temperature probe having a transmitting coil and a receiving coil or a transmit/receive coil, and used in an NMR apparatus, comprising: an opposed heat exchanger cooling a cooling medium at a room temperature from a compressor to 70 K or less in one side; a cooling apparatus structured by connecting at least two refrigerating machines having two stages in series, and cooling the cooling medium from said opposed heat exchanger, said two cooling stages having a first cooling stage capable of cooling to 30 K or less and a second cooling stage capable of cooling to 4 K or less; a probe portion having a first heat exchanging portion executing a heat exchange between the cooling medium from said cooling apparatus and said receiving coil or said transmit/receive coil; a circulation structure circulating the cooling medium from said probe portion into the other side of said opposed heat exchanger; wherein said probe portion is provided with a second heat exchanging portion executing a heat exchange between the cooling medium from said first heat exchanging portion and a masking shield internally wrapping the cooling medium from said first heat exchanging portion and said receiving coil or said transmit/receive coil, and the cooling medium from said second heat exchanging portion is circulated into the other side of said opposed heat exchanger; and wherein a buffer tank having a larger capacity than the cooling medium flowing through said circulation structure is provided between an outlet of said compressor and an inlet of said opposed heat exchanger.