Results of Measurements on a 50 MHz Cavity Driven by a 250 kW Power Amplifier and the Present Status of the RF System of the SIN Cyclotron

The latest developments on the rf system of the SIN ring cyclotron will be described. With a power input of 250 kW in one accelerating cavity lpar;Qo = 32 000) more than 700 kV peak voltage was measured. At a cavity voltage of 500 kV the phase and amplitude stability are 0,4° and 1 in 103 respectively. The following subjects are discussed in detail: ‐ Automatic tuning system ‐ Multipactoring ‐ X‐rays at high cavity voltage ‐ Development of a flat‐topping cavity ‐ The future rf test program