THE 100 MHZ RF SYSTEM FOR MAX-II AND MAX-III

The MAX-II synchrotron radiation source has since 1997 been operated routinely with a double RF system, 500 MHz active plus 1.5 GHz passive. Four Landau cavities have successfully provided increased Touschek beam lifetime, and damping of coupled bunch mode instabilities. However, the delivered power from the present 500 MHz RF system will be marginal for the operation of the planned MAX-II SC wigglers, with 250 mA circulating beam current. It is shown that it is favourable to change to a 100 MHz system, with one 500 MHz Landau cavity, both considering power consumption, beam lifetime and beam stability. The new RF system and the cavities, that are being built at MAX-lab, are described. The same RF combination and type of cavities will be used at the VUV source MAX-III (Less)