Design of 83.2 MHz RF cavity for SKKUCY-10 cyclotron

A vertical half-wavelength RF cavity was designed for SKKUCY-10 cyclotron. The design of the RF cavity was implemented in three stages as follows. Firstly, the structure of the cavity was modeled as an HWR without Dee geometry. Secondly, the Dee configuration including geometry was modeled, and finally, the power coupler, fine tuner, and the central region including ion source and puller were designed. For the first structure, the length of the resonator was selected as 560 mm to minimize the resonance frequency. For the second structure, the resonance frequency, unloaded quality factor (Q₀) and electric field strength were simulated to be 83.2 MHz, 5830 and 7.8 MV/m, respectively. A coupling coefficient of (β) 0.98 and characteristic impedance (Z₀) of 50 Ω were obtained for the final structure. The RF cavity was fabricated based on design and resonance frequency, coupling coefficient were measured 83.2 MHz, 1.09, respectively. The reflection ratio of 5 ± 0.1% and cavity pick-up power of 0–0.12 μW were tested by increasing the input RF power from 0 to 9 mW. The specifications of the RF cavity showed that there is a good agreement between the simulation and experimental results.