R. F. System for a Compact Isochronous Cyclotron

The R.F. system of the Philips Compact Isochronous cyclotron is described. It is built completely inside the vacuum chamber resulting in a very compact construction. The Dees are situated in two opposite valleys of the four-fold symmetrical pole faces of the magnet. Two rectangular coaxial lines are connected to the Dees and terminated by movable shorting plates. The 15 kW R.F. oscillator, placed outside the vacuum chamber, is coupled capacitively to one line. The frequency range is continuously variable from 35 to 72 MHz, the maximum Dee voltage being 23 kV.