Nuclear magnetic resonance apparatus
First Claim
1. A nuclear magnetic resonance apparatus, comprising a magnet which comprises an electromagnetic coil system for generating a homogeneous magnetic field in an examination space which is enclosed by the magnet, and a shield for the external stray field of the coil system arranged coaxially about the electromagnetic coil system, the shield comprising a plurality of rods of a soft magnetic material which are axially directed and uniformly spaced on at least a portion of a cylindrical surface which extends concentrically about the coil system, the length of said rods being at least equal to the axial length of the coil system.
1 Assignment
0 Petitions
Accused Products
Abstract
A nuclear magnetic resonance apparatus comprises an electromagnetic system in which a shield of a magnetic material is arranged about the coil system for the homogeneous magnetic field. By providing the magnetic material, for example soft iron, directly about the coil system, a comparatively compact magnet with an intensified, interference-insensitive homogeneous magnetic field is obtained. Instead of using a closed cylinder, use can alternatively be made of a cylinder which is formed by rods. The latter is notably attractive for shielding at a larger distance, the original field in the coil then being influenced to only a minor extent. A similar shielding can be obtained by means of a Helmholtz coil pair.
-
Citations
9 Claims
- 1. A nuclear magnetic resonance apparatus, comprising a magnet which comprises an electromagnetic coil system for generating a homogeneous magnetic field in an examination space which is enclosed by the magnet, and a shield for the external stray field of the coil system arranged coaxially about the electromagnetic coil system, the shield comprising a plurality of rods of a soft magnetic material which are axially directed and uniformly spaced on at least a portion of a cylindrical surface which extends concentrically about the coil system, the length of said rods being at least equal to the axial length of the coil system.
Specification