Patent attributes
RF device (1) able to generate an RF acceleration voltage in a synchrocyclotron. The device comprises a resonant cavity (2) formed by a grounded conducting enclosure (5) and enveloping a conducting pillar (3) to a first end of which an accelerating electrode (4) is linked. A rotary variable capacitor (10) is mounted in the conducting enclosure at a second end of the pillar, opposite from the first end, comprising at least one fixed electrode (stator) (11) and a rotor (13) exhibiting a rotation shaft (14) supported and guided in rotation by galvanically isolating bearings (20), said rotor (13) comprising one moveable electrode (12) possibly facing the stator (11). When the shaft (14) rotates, the stator and the moveable electrode together form a variable capacitance whose value varies cyclically with time. The rotor (13) is galvanically isolated from the conducting enclosure (5) and from the pillar (3). The stator (11) is connected to the second end of the pillar (3) or to the conducting enclosure (5). The rotor is respectively coupled capacitively to the conducting enclosure or to the pillar. This makes it possible to dispense with sliding electrical contacts between the rotor and respectively the conducting enclosure or the pillar.