Sliding contacts for tuners in high power RF resonators

A sliding contact configuration has been developed for use in high power rf resonators. The configuration allows a large number of contacts so that each carries only a small current. The tolerance of the contacts to structural inaccuracies is relatively large and the configuration is much less complex than the clamping contact mechanism usually used at high power. The theory, design and material considerations are discussed and the practical application in the main tuners of the Chalk River Super conducting Cyclotron described. Reliable operation has been obtained in the 31-62 MHz frequency range up to 50 A/cm linear current densities. The configuration is clearly capable of considerably higher current densities at these frequencies