Patent ID: 7222490

Claim:
An NMR spectrometer for investigating a sample, the spectrometer comprising: a cryostat having a room temperature bore; a helium tank disposed in said cryostat; an NMR magnet system disposed in said helium tank; an NMR probe head disposed in said room temperature bore, said probe head having a cooled RF resonator for receiving NMR signals from the sample and a cooled pre-amplifier; an evacuacted and thermally insulated housing disposed outside of said cryostat; a multi-stage compressor-operated refrigerator disposed in said housing, said refrigerator having a cold head and several heat exchangers at different temperatures; a least one cooling circuit having first cooling lines communicating with said refrigerator and communicating with said probe head to cool said probe head with said refrigerator; at least one transfer line, disposed between said housing and said probe head and structured to thermally insulate said cooling lines; a LN 2 tank or radiation shield disposed in said cryostat and surrounding said helium tank; and second cooling lines communicating with said refrigerator and said helium tank or radiation shield by means of which said refrigerator cools said LN 2 tank or radiation shield.