Radio frequency energy recovery for particle accelerators

Abstract

During the operation of particle accelerators considerable amount of power coming to RF cavities is converted to heat in load resistors placed after RF cavities. When the CERN’s Super Proton Synchrotron is analyzed as an example, it can be seen that 76 per cent of the power delivered to an RF cavity is dissipated in loads. Under CERN-BE-RF-BR group, RF Energy Recovery Project had been started to study the feasibility of recovering this wasted power. This thesis mainly focuses on the work done during the feasibility studies in 2010. Possible methods for recovering this wasted power was explained and feasibility was discussed. The method which is converting this excess RF power into DC power and utilizing was adopted. Overall recovery system and possible ways of converting RF power to DC power were discussed. For RF/DC conversion, resonant rectifiers which employ semiconductor diodes were chosen. Simulations were performed for different resonant rectifier architectures with PSpice. Most suitable circuit was chosen and prototype of this circuit was constructed. Measurements were performed for different input power levels, up to 400W, and RF to DC conversion efficiency reaching up to 88 per cent was reached.