Oxford Instruments Nanotechnology Tools Limited

Micromass UK Limited

Wuhan Zhongke Niujin Magnetic Resonance Technology Co., Ltd

John Garside

Kenneth Russell Worthington

Matthias Buehler

Dieter Jedamzik

Timothy John Foster

Daniels Tortorella

Theo Hertrich

Xing Yuan

Doreen Wernicke

Gavin Crowther

Daniele Tortorella

Simon Kingley

A cryogenic refrigeration system is provided having particular application in cooling a Magnetic Resonance Imaging system. The cryogenic refrigeration system comprises a conduit arranged as a cooling circuit through which a coolant fluid is pumped, the conduit being in thermal communication with a least one cooled stage for cooling the coolant fluid to a first temperature, and wherein the conduit comprises a cryotrap in communication with the coolant fluid, the cryotrap being operable to remove contaminants from the coolant fluid by cryogenic pumping. The conduit further comprises a flow impedance for cooling the coolant fluid to a second temperature lower than the first temperature, and a hydrogen filter upstream of the flow impedance and in communication with the coolant fluid, the hydrogen filter being cooled to a temperature below the freezing point of hydrogen in the coolant fluid and operable to remove contaminant hydrogen from the coolant fluid.

Reduction of blockages in a cryogenic refrigeration system such as for magnetic resonance imaging systems

Apparatus for controlling a cryogenic cooling system is described. A supply gas line (A) and a return gas line (B) are provided which are coupled to a compressor () and to a mechanical refrigerator () via a coupling element (). The coupling element is in gaseous communication with the supply (A) and return gas lines and supplies gas to the mechanical refrigerator (). The pressure of the supplied gas is modulated by the coupling element in a cyclical manner. A pressure sensing apparatus () monitors the pressure in at least one of the supply and return gas lines. A control system () is used to modulate the frequency of the cyclical gas pressure supplied by the coupling element in accordance with the pressure monitored by the pressure sensing apparatus. An associated method of controlling such a system is also described.

Apparatus and method for controlling a cryogenic cooling system

A cryogenic cooling apparatus comprises a supply gas line and a return gas line adapted to be coupled to a compressor. A coupling element is positioned in gaseous communication with the supply and return gas lines, the coupling element being adapted in use to supply gas to a mechanical refrigerator so that the pressure of said supplied gas is modulated by the coupling element in a cyclical manner. A sensing system is used to monitor the operational state of the mechanical refrigerator and a control system modulates the frequency of the cyclical gas pressure supplied by the coupling element in accordance with the monitored operational state. The mechanical refrigerator has a first cooled stage and a second cooled stage, the second cooled stage being adapted to be coupled thermally with target apparatus to be cooled. A selectively coupleable thermal link is provided for thermally coupling the first cooled stage of the mechanical refrigerator to the second cooled stage in dependence upon the operational state of the mechanical refrigerator. A method of use of the apparatus is also disclosed. The apparatus and method have particular application in a Magnetic Resonance Imaging system.

Cryogenic cooling apparatus and method such as for magnetic resonance imaging systems

A pulse tube refrigerator (PTR) comprising a pedestal head and a regenerator tube assembly is provided having particular application in cooling a Magnetic Resonance Imaging system. The PTR comprises a pedestal head and at least one cooled stage, the at least one cooled stage being mounted to a distal end, with respect to the pedestal head, of each of an associated regenerator tube and an associated pulse tube, the associated regenerator tube and associated pulse tube together providing pressurized coolant gas to the at least one cooled stage, wherein the associated regenerator tube and the associated pulse tube are elongate along substantially parallel axes; and further arranged, wherein, the displacements of the distal ends of each of the associated regenerator tube and the associated pulse tube in response to the cyclical changes in coolant pressure, are substantially the same when the pulse tube refrigerator is in use.

Apparatus for reducing vibrations in a pulse tube refrigerator such as for magnetic resonance imaging systems

An assembly for operating a cryocooler pedestal is provided. The assembly is operable when in use to provide a cryocooler pedestal with cyclical gaseous connection to high pressure and low pressure gas supply lines, and has a return conduit through which gas is caused to flow from the cryocooler pedestal into the low pressure supply line. The assembly further comprises a dispersion chamber adjacent the return conduit and in flow communication therewith through a plurality of orifices so as to reduce acoustic noise. The assembly has particular application in cooling a Magnetic Resonance Imaging system.

Apparatus for reducing noise in a cryocooler such as for magnetic resonance imaging systems

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Witney, United Kingdom

John Garside