Perpendicular biased ferrite tuned RF cavity for the TRIUMF kaon factory booster ring

Abstract

The rf cavity for the booster ring requires a frequency swing of 46 MHz to 62 MHz at a repetition rate of 50 Hz. The possibility of using the LANL booster cavity design with a yttrium garnet ferrite tuner biased perpendicular to the rf field, in the longitudinal direction, is being investigated. In order to minimize the stray magnetic biasing field on the beam axis, an alternative scheme similar to the design being proposed for the LANL main ring cavity in which the ferrite is perpendicular biased in the radial direction, is being considered. The behavior of the rf cavity and the magnetizing circuit for both designs are discussed. RF Cavity AnalysisThe rf analysis of the LANL booster cavity design has been described in other papers [1,3]. The tuning analysis [4] of a 6 ring radial biased rf tuner,using the same size rings as the LANL booster cavity design, is shown in figure 3. One of the problems encountered with radial biasing is the considerable width of the space between the ferrite rings for the magnetizing coils which makes the input reactance of the tuner less sensitive to changes in the ferrite permeability. As a consequence a larger permeability range and a lower minimum permeability are required. To obtain a low permeability of 1.2 as indicated in figure 3, a

A model for ferrite-loaded transversely biased coaxial resonators

“…Ferrite-loaded, magnetically tuneable coaxial cavity resonators operating in the radio frequency (RF) range are commonly used in particle accelerators [1][2][3]. The frequency of resonance in such cavities can be tuned by changing the DC magnetic field applied onto the ferrite elements.…”