Raghavan Jayakumar

US Patent:

48961280, Jan 23, 1990

Filed:

Nov 30, 1988

Appl. No.:

7/278124

Inventors:

John J. Wollan - Florence SC
Raghavan Jayakumar - Florence SC
Vincent Abruzzo - Utica NY
James Lee - Lake City SC

Assignee:

General Electric Company - Milwaukee WI

International Classification:

H01F 500

US Classification:

335299

Abstract:

A support structure for a superconducting solenoid magnet has a set of five symmetrically and coaxially arranged nonferrous support rings. The central support ring mounts two magnet coils and the other four rings each mount one magnet coil so as to restrain the magnet coils from collapsing toward the center along the magnet bore axis and also to resist radially and circumferentially acting hoop stresses to which the coils are subjected. Tubular struts are symmetrically arranged about the magnet bore axis between adjacent support rings and are seated at their ends in counterbores in the support rings to separate and space apart the support rings. Threaded rods extend through the tubular struts and adjacent support rings to fasten the adjacent rings together.

US Patent:

48127973, Mar 14, 1989

Filed:

Mar 22, 1988

Appl. No.:

7/171824

Inventors:

Raghavan Jayakumar - Florence SC

Assignee:

General Electric Company - Milwaukee WI

International Classification:

H01F 500

US Classification:

335299

Abstract:

A superconducting coil assembly for a nuclear magnetic resonance imaging system has a main coil for producing a static magnetic field within a cylindrical volume. a conventional set of active correction coils are provided to spatially homogenize the magnetic field. A pair of passive compensation coils are electrically connected in series and shorted together. The compensaton coils are inductively coupled to the main coil so that the temporal decay of the current in the main coil induces current in the compensation coils. The magnetic field harmonics produced by this induced current is opposed to the magnetic field harmonics produced in the correction coils by main coil decay. The compensation coil thereby counteracts the inhomogeneity effects from the main coil current decay.

US Patent:

50014471, Mar 19, 1991

Filed:

Aug 23, 1989

Appl. No.:

7/397238

Inventors:

Raghavan Jayakumar - Florence SC

Assignee:

General Electric Company - Milwaukee WI

International Classification:

H01F 500

US Classification:

335299

Abstract:

A reduced length, high field strength magnet, comprised of a number of superconducting magnet coils has ferromagnetic compensation rings positioned coaxially around the magnet bore axis to reduce axial inhomogeneities. The rings are positioned symmetrically around the bore axis centerpoint. Both the position of the magnet coils and the position of the ferromagnetic compensation rings are determined by an iterative optimization process checked by finite element modeling.