Patent ID: 6534984
Filing Date: 2003-03-18
Classification: G01R

Abstract:
A main field magnet arrangement for a one-sided magnetic resonance device, said magnet arrangement generating a homogeneous magnetic field B in a working volume, the working volume and the main field magnet being disposed on different sides of a plane E, the main field magnet having a geometrical shape which permits positioning of a radio frequency (RF) receiver coil system and optionally a gradient coil system on a same side of the plane E as the main field magnet, the main field magnet arrangement comprising:a radially outer group of outer field generating elements made from permanent magnetic material magnetized in a same sense as a direction of the magnetic field B in the working volume; and a radially inner group of inner field generating elements made from permanent magnetic material magnetized in said same sense as said direction of the magnetic field B in the working volume, said radially inner group surrounded by said radially outer group, said radially inner group having an inner surface facing the working volume which is axially further separated from a center of the working volume than an outer surface of said radically outer group, facing the working volume thereby forming an inner depression in an axial direction in said radially inner group, said inner field generating elements formed of parallel mutually adjacent inner prismatic rods, said inner prismatic rods having axes defining a grid of lines having a grid constant a, wherein individual surfaces of said inner prismatic rods have differing axial separations from the center of the working volume which deviate from a rotationally symmetric distribution about an axis A extending through the center of the working volume, said grid of lines extending through at least four grid constants in each of two principal directions.