The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 23, 1989
Filed:
Jul. 20, 1988
Moriaki Takechi, Ako, JP;
Abstract
A superconducting electromagnet for nuclear magnetic resonance imaging has a pair of Z gradient coils surrounded by a heat shield. The heat shield comprises an electrically-conducting tube having one or more cylindrical portions which have longitudinal slits formed therein and at least two annular portions which do not have slits and which are integral with the cylindrical portions. The annular portions are inductively coupled with the Z gradient coils. The axial positions of the centers of the annular portions are selected such that the sum of the cubic term in the expression for the magnetic field generated by eddy currents which are induced in the annular portions and the cubic term in the expression for the magnetic field generated by the Z gradient coils is equal to zero. The resulting composite magnetic field varies substantially linearly along the longitudinal axis of the electromagnet.