Patent ID: 7030613
Filing Date: 2006-04-18
Classification: G01R

Abstract:
1. A nuclear magnetic resonance measuring apparatus comprising: an NMR probe head equipped with an NMR receiver coil and an irradiation coil; a preamplifier, arranged in said probe head, for amplifying the NMR signal received by said NMR receiver coil; a coil cooling heat exchanger, arranged in said probe head, for exchanging heat between said NMR receiver coil/irradiation coil and coolant; a preamplifier heat exchanger, arranged inside said probe head, for exchanging heat between said preamplifier and coolant; a cooling device capable of cooling and compressing the coolant; a first transfer tube for transferring the coolant from said cooling device to said probe head; a second transfer tube for transferring the coolant from said probe head to said cooling device; a third transfer tube for transferring the coolant from said cooling device to said probe head; and a fourth transfer tube for transferring the coolant from said probe head to said cooling device; said nuclear magnetic resonance measuring apparatus further characterized in that: said cooling device further comprises: a cryo-cooler further containing a first cooling stage having a first stage heat exchanger and a second cooling stage having a second stage heat exchanger; a compressor for compressing the coolant; a first counter-flow heat exchanger and a second counter-flow heat exchanger; said first cooling stage has a first stage temperature higher than the second stage temperature of said second cooling stage; said compressor is capable of circulating the coolant via the path comprising said first counter-flow heat exchanger, third transfer tube, preamplifier heat exchanger, fourth transfer tube, first heat exchanger, second counter-flow heat exchanger, second stage heat exchanger, first transfer tube, said coil cooling heat exchanger, transfer tube, second counter-flow heat exchanger and first counter-flow heat exchanger, in that order; and pressure control valves that all the amount of coolant passes through are arranged in series in at least one position along said coolant circulating path and are capable of reducing the pressure of the coolant passing through said pressure control valves.