PROPERTIES OF SPIRAL LOADED CAVITIES

Spiral loaded cavities are compact rf- structures with a high efficiency in a frequency range between 27MHz and 200 MHz and particle Energies from approx. 10 KeV/A to about 50 MeV/A. We have built a number of cavities for applications as post accelerator structures. debuncher and rebuncher cavities. Typical shuntimpedances are between 20 and 60Mn/m. Spiral structures have been operated with accelerating fields up to 2.5 MV/m. Properties of spiral loaded cavities will discribed and applications will be discussed. In order to calculate the resonance frequency we start with the equivalent circuit of the resonator (fig. 2). C is the capacity between the spiral arm and the tank walls and the capacity of one acceleration gap. L i