In a tomography system having a superconducting magnet and gradient coils, a cooling arrangement for cooling the gradient coils includes a cooling circuit which itself comprises an outward branch carrying cooling fluid to the gradient coils and a return branch carrying cooling fluid away from the gradient coils. At least part of each of the outward and return branches is formed of an electrically conductive conduit. The conduits provide electrical connections from a power supply to the superconducting magnet. In one embodiment, a first end of the bore of the first electrically conductive conduit is fluidly coupled to the bore of the outward branch; and a first end of the bore of the second electrically conductive conduit is fluidly coupled to the bore of the return branch. An electrically isolating bridging conduit is fluidly coupled between second ends of the first and second electrically conductive conduits.