Apparatus for nuclear spin tomography having superconducting base field magnetic coils and a radiation shield

US4876510A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Horst Siebold · Erlangen, DE
• Gunter Ries · Erlangen, DE

Key dates

• Filing date: May 12, 1988
• Grant date: Oct 24, 1989
• Expiry date: May 12, 2008

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S505/85
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Magnet coil system for nuclear spin tomography has superconducting coils for generating a homogeneous magnetic base field and nonsuperconducting coils within an interior region defined by the base field coils for developing magnetic field gradients. At least one cooled radiation shield of electrically and thermally conductive material is arranged between the gradient coils and the superconducting base field coils. To prevent eddy currents started in the radiation shield from distorting the gradient fields, the radiation field contains superconducting material of a "second kind" that is a high temperature superconductor. The superconductor is in a nonsuperconducting state at the start of an excitation process for the base field coils and in a superconducting state during the undisturbed operation of the magnet coil system.