Patent ID: 6215384
Filing Date: 2001-04-10
Classification: G01R

Abstract:
A magnet comprising:a) a longitudinally-extending axis;b) at least two main separated coils coaxially aligned with said axis and carrying an electric current in a first direction;c) at least one inner magnetizable member which is coaxially aligned with said axis, longitudinally spaced apart from and intermediate said at least two main coils;d) at least one shielding coil coaxially aligned with said axis, disposed radially outward from said at least two maine) at least two magnetizable members which are not carrying an electric current, which are longitudinally spaced apart from each other, which are disposed radially outward from said at least two main coils and said at least one inner magnetizable member, and which are disposed radially inward from said at least one shielding coil;f) said at least two magnetizable members being cylindrical members, interposed between said at least one main and correction coils and said at least one shielding coil.