Superconducting magnet with magnetic shielding

A superconductive magnet comprising:

• a) a generally longitudinally extending axis;
• b) a generally annularly-cylindrical-shaped housing generally coaxially aligned with said axis, having annular, longitudinally-spaced-apart first and second end walls, and having radially-spaced-apart outer and inner cylindrical walls, wherein said first end wall and said outer cylindrical wall are generally magnetizable walls, and wherein said inner cylindrical wall is a generally non-magnetizable wall;
• c) a superconductive coil assembly having at least one generally solenoidal-shaped main superconductive coil which is generally coaxially aligned with said axis, which is disposed within and generally spaced apart from said housing, which has a number of ampere turns, and which carries an electric current generally in a first direction;
• and
• d) a first resistive deflection coil generally coaxially aligned with said axis, disposed outside said housing radially proximate said outer cylindrical wall and longitudinally closer to said first end wall than to a midpoint located on said axis longitudinally halfway between said end walls, and carrying an electric current generally in an opposite direction to said first direction, wherein said housing is an open-magnet housing and wherein said second end wall is a generally non-magnetizable wall, and wherein each of said first and second end walls are connected to each of said inner and outer cylindrical walls to define said annularly-cylindrical shape of said housing.