Abstract: An RF cavity includes a chamber, a conductive wall that encloses the chamber and has an inner side and an outer side, a switch arrangement comprising a plurality of solid-state switches arranged along a circumference of the wall around the chamber, wherein the solid-state switches are connected to the conductive wall such that RF currents are induced in the conductive wall when the switch arrangement is activated, as a result of which RF power is coupled into the chamber of the RF cavity, and a shielding device located on the outer side of the conductive wall, along a circumference of the RF cavity, the shielding device configured to increase the impedance of a propagation path of RF currents along the outer side of the wall such that the RF currents coupled into the wall are suppressed on the outer side of the wall.