Abstract: An ion therapy system comprises a particle accelerator (1) mounted on a rotatable gantry (2). The particle accelerator includes a superconducting coil (17) which rotates about its axis as the particle accelerator rotates about the gantry axis in use to direct an output beam towards a target from different directions. The particle accelerator is rotatable through (180) degrees to move the beam through a corresponding arc. The particle accelerator includes cooling system arranged to cool the coil as the coil rotates. The superconducting coil (17) is mounted in a coil support (25). The coil is surrounded by a cryogen chamber (32) which is located radially outwardly from the coil (17) on the other side of the support (25). The cryogen chamber is in fluid communication with a cryogen recondensing unit (29) whereby vaporized cryogen may flow from the cryogen chamber (32) to the cryogen recondensing unit (29) to be recondensed in use before returning to the cryogen chamber.

Abstract: An MRIS gradient coil structure has coiled tubes for carrying a cooling medium to cool the coil structure. The inlet and outlet of the coiled tubes are insulated electrically from the remainder thereof by a ceramic insulator.

Abstract: An MRIS gradient coil structure has coiled tubes for carrying a cooling medium to cool the coil structure. The inlet and outlet (15, 26) of the coiled tubes are insulated electrically from the remainder thereof by a ceramic insulator (20).

Abstract: A gradient coil structure for use in MRI apparatus has a main gradient coil 20 and a shielding coil 21, a portion of the shielding coil being disposed outwardly from the main coil. The coils are configured so that in a peripheral region 25 relative to the image region 22 the are almost coincident and the coils extend forwardly at an angle to the remainder of the main coil so that the main coil appears concave from the imaging region 22. This arrangement provides improved shielding efficiency.