Intermagnetics General Corporation

F Scott Murray

Philip A Jonas

Leo Blecher

Ralph C Longsworth

Constantinos Minas

Michael J Hennessy

Ronald E Hintz

Michael Boiarski

Robert E Wilcox

Richard T Woods

Michael Frantsov

Hung B Zou

An open or split type MRI apparatus has two axially spaced magnet coil half sections separated and supported by a compact support structure. Only two diametrically opposed supports are needed to react the high axial and torsional loads produced or received by the MRI apparatus. One support is loaded under pure compression, and the other support is loaded under compression and tension.

Support structure for open MRI apparatus

A superconducting magnet is accessible for ramping within a cryostat by inserting flexible current leads through openings in the cryostat and pushing and twisting these leads inward until connections are made with electrical contacts provided on the superconducting magnet. For each current lead, a permanently installed channel guides the lead as it is pushed through the external opening and extends to make contact with the magnet terminal. The guide channel extends outside of the cryostat and includes an internal or external bend, whereby the overhead space required for the cryostat/magnet assembly may be reduced. After ramping, the leads are withdrawn.

Method and apparatus for connecting high current ramping leads to a

A MRI cryostat, which contains a superconducting magnet operating in a bath of liquid helium, reduces the boil-off rate of helium by intercepting most of the heat in-leakage by means of a throttle cycle (TC) refrigerator operating at a low side temperature of about 90K. The main heat exchanger for the throttle cycle refrigerator is located within or immediately adjacent to the cryostat housing and delivers cold liquid to a cold heat exchanger that is in thermal contact with an outer radiation shield, support struts, neck tube and electrical leads inside the cryostat. Heat is intercepted by the outer shield from essentially all paths between a 300K ambient and a 4K load temperature, which temperature results from liquid helium boil-off to atmosphere. A second, inner radiation shield at 35K is cooled by gaseous helium that boils from the liquid helium bath. There are no moving parts of the refrigeration system in the cryostat. Thus, vibration, noise and disturbance of the magnetic field are reduced. The refrigerator installation is small and low in cost; power consumption is reduced relative to the prior art.

MRI cryostat cooled by open and closed cycle refrigeration systems

A magnetic suspension system and a procedure for operating the system employ a superconducting magnet having a lift coil assembly for developing a magnetic field to interact with the magnetic field of an object to be supported about the superconducting magnet. Smaller and larger magnet coils are provided in the superconducting magnet with counter rotating flow of current to introduce a depression in a potential energy surface above the superconducting magnet, this allowing the object to seek a height at the depression for stably locating the object. The system and methodology employs a set of control coils which are energized to orient and to translate the object to maintain a desired position and orientation. Pairs of the control coils are energized to produce a tilting of the object, as in roll or pitch, or a displacement of the object relative to the vertical axis.

Large gap magnetic suspension system with superconducting coils

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Schenectady, NY, United States of America

F Scott Murray