Modelling the TRIUMF RF Cavity Using the Code RFQ3D

Development work on the TRIUMF cyclotron RF cavity requires an efficient code to study the effects on voltage distributions of resoaator geometry nonuniformity, including misalignment of the cantilevered cavity walls, the end flux guides and the centre post. A quasi-three-dimensional code, RFQ3D, although originally written for radio frequency quadrupole cavity studies, has been successfully adapted to simulate the TRIUMF cavity. The code uses four one-dimensional coupled transmission line equations to calculate the voltage distributions along the dee gap and allows for local variations in the transmission line inductance and capacitance. The effects of individual resonator components on the accelerating voltage profile and the RF leakage for both the fundamental and third harmonic frequencies are calculated and compared with precise 1:10 model measurements.