Abstract: A variable collimator 10 for shaping the cross-section of the beam 100 is described. The collimator relies upon rods 16 which are positioned around the beam axis a-a with the rod 16 axis b-b perpendicular to the beam axis. The rods are shaped by shaping member 24 which is cut to the shape of an area of a patient or other surface to be irradiated.

Abstract: A collimator apparatus (10 or 100) including one or more bundles of nested rods (11, 11a or 101 or 101a or 201) which define a surface (112, 112a) which interferes with a beam of radiation is described. The apparatus particularly uses coil spring (48) between and along the axis (a--a or c--c) of the rods which are compressed by blocks (13, 14, 13a and 14a or 103, 104, 103a and 104a) to lock the rods in position in holes in the blocks. The apparatus is particularly useful for shaping radiation beams for patient treatment.

Abstract: An improved superconducting cyclotron (10) particularly useful for medical or therapeutic purposes is described. The vessel (105) for liquified gas surrounding superconducting coils (101, 101a) is provided with a capillary tube (200) joined to a semi-circular tube (123) leading into an exit tube (201) from the vessel which provides Joule-Thompson effect cooling upon flow of a portion of the liquified gas in the vessel into the semi-circular tube. The cooling maintains the liquified gas in the vessel in a subcooled condition to prevent boiling. The liquified gas from the exit tube can be used to cool the magnetic poles (103, 104) and then can be vented to the atmosphere or recycled. A special external magnetic yoke (102) configuration for weight reduction is described. Also described is a flexible hose (37) for supplying the liquified gas to and from the cyclotron which is mounted in a helical coil so as to allow up to a 360.degree. of rotation of the cyclotron.

Abstract: A synchrocyclotron with superconducting coils (1) is described. The coils are provided in a vessel (4) which is supported by low heat leak members (6) in a cryostat (7). A liquified gas (helium) is provided in the vessel to cool the coils so as to render them superconducting.

Abstract: An apparatus 10 including a valveless rotatable, continuously vented vessel 11 for containing a liquid is described. The vessel can be confined in a vacuum chamber 15 to reduce heat losses from the liquid in the vessel. The apparatus is particularly adapted for containing superconducting coils in a cyclotron 100.

Abstract: A superconducting cyclotron (10) rotatable on a support structure (11) in an arc of about 180.degree. around a pivot axis (A--A) and particularly adapted for medical use is described. The rotatable support structure (13, 15) is balanced by being counterweighted (14) so as to allow rotation of the cyclotron and a beam (12), such as a subparticle (neutron) or atomic particle beam, from the cyclotron in the arc around a patient. Flexible hose (25) is moveably attached to the support structure for providing a liquified gas which is supercooled to near 0.degree. K. to an inlet means (122) to a chamber (105) around superconducting coils (101, 102). The liquid (34) level in the cyclotron is maintained approximately half full so that rotation of the support structure and cyclotron through the 180.degree. can be accomplished without spilling the liquid from the cyclotron.