Electricity: measuring and testing – Particle precession resonance – Spectrometer components
Patent
1990-07-27
1992-08-11
Williams, Hezron E.
Electricity: measuring and testing
Particle precession resonance
Spectrometer components
335216, G01V 300, H01F 100
Patent
active
051383268
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a magnetic field generating assembly and a method of constructing such an assembly.
2. Description of the Background Art
Magnets for generating high strength magnetic fields are used in a wide variety of applications including nuclear magnetic resonance (NMR). In the case of whole body imaging and the like, large magnet structures are required leading to very high costs. One of the significant reasons for these high costs is the need to provide superconducting material which historically has comprised copper cooled to liquid helium temperatures. This requires the provision of efficient cryostats and the like.
Low temperature superconductivity is difficult to maintain in large structures because of the small "packets" of heat that can raise the temperature of the conductor above the critical temperature for superconductivity. Elegant forms of the conductor design have been created to minimise electromagnetic sources of heat arising within the conductor during operation. However, as magnets become larger, and the systems in which they are incorporated more complex, support engineering to avoid macroscopic heat pulses from structural movement and heat leaks from the environment become costly.
Recently, relatively high temperature superconducting materials have been discovered. By "relatively high temperature" we mean temperatures higher than for example liquid nitrogen temperatures (77K) at which the materials superconduct.
In order to duplicate conventional approaches using coils of wire it would be necessary to produce long lengths of wire made from the high temperature superconducting materials. In practice, this is not possible since the high temperature materials only carry useful current densities if they are made by very specialized fabrication processes, particularly those that apply to thin films. There would be no possibility of providing many kilometers of thin film like material to wind the magnet conventionally.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, a magnetic field generating assembly comprises at least one magnetic field generating module of relatively high temperature superconducting material; and a magnetic flux guide positioned relative to the module so that magnetic flux generated by the module is coupled into the guide and conveyed to a position remote from the module.
We have devised a new concept in which the relatively high temperature superconducting materials are used in efficient, small elements or modules which are assembled with a magnetic flux guide so as to construct a useful magnet structure. This enables thin film formation techniques to be used and avoids the problem of the structural frailty of the materials.
Each module can be considered as a source of magneto-motive force (mmf) so that when the modules are combined, the summed mmf can be obtained and be usefully directed.
The assembly can be arranged in a variety of ways to achieve different generator configurations. For example, there may be provided a number of modules and associated flux guides arranged spaced apart in a two dimensional array so as to generate magnetic fields in the same sense and to project into a working region a magnetic field of controlled characteristics.
In another example, a generally U-shaped flux guide may be provided with one or more modules at each end and arranged so as to generate a magnetic field of controlled characteristics in the mouth of the U. In this configuration, which can be realised as a C-magnet, the modules will usually be arranged to face each other across a gap with the magnetic field of controlled characteristics being generated in the gap.
In another configuration, a pair of magnetic flux guides are provided with one or more modules positioned adjacent one end of the guides while magnetic fluxes are conveyed by the guides to their other ends so as to generate a magnetic field of controlled characteristics in a working region defined between those othe
REFERENCES:
patent: 4176291 (1979-11-01), Rabinowitz
patent: 4190817 (1980-02-01), Rabinowitz
patent: 4641119 (1987-02-01), Moore
patent: 4656447 (1987-04-01), Keim et al.
patent: 4694269 (1987-09-01), Burnett et al.
patent: 4717437 (1988-01-01), Blaugher et al.
Armstrong Alan G. A. M.
Cohen Jeffrey D.
Edwards Donald
Hsu Che-Hsiung
Kountz Dennis J.
Arana Louis M.
E. I. du Pont de Nemours & Company
Oxford Medical Limited
Williams Hezron E.
LandOfFree
Magnetic field generating assembly and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Magnetic field generating assembly and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic field generating assembly and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-349555