Magnet system for nuclear spin tomography having superconducting coils and a cold shield

摘要

A magnet system for a nuclear spin tomography installation contains annular superconducting coils for generating a magnetic background field and nonsuperconducting gradient coils. A hollow cylindrical thermal shield fits between the gradient coils and the superconducting coils. According to the invention, the thermal shield at the front faces is formed from tubular end pieces. The front faces have a greater specific electrical resistance than a tubular intermediate piece of the thermal shield that extends between the end pieces and cover at least the area of the gradient coils.