A High Frequency Mosfet Driver for the Titan Facility at TRIUMF

TRIUMF's Ion Trap for Atomic and Nuclear Science (TITAN) Radio Frequency Quadrupole (RFQ) Beam Cooler is a device that cools and collects short-lived isotopes, with half-lives as short as 10 ms, created by an Isotope Separator and Accelerator (ISAC). An RF square wave driver (RFSWD), that must have rise and fall times of less than 125 ns (10% to 90%), performs 2-dimensional focusing of the ion beam within the RFQ, along planes normal to the beam's intended trajectory, to confine ion motion along a stable path; hence the ions can be trapped and collected for extraction. The RFSWD, which is based on previous kicker designs developed at TRIUMF, employs stacks of MOSFETs, operating in push-pull, to generate high voltage (HV) rectangular waveforms at a prescribed frequency and duty cycle. Currently a 500 V, 2 MHz drive system is undergoing tests, however, the system configuration allows for operation with higher voltage amplitudes and a repetition rate from 300 kHz up to 3 MHz, continuous. Technical details of the design, operation and performance of the RFQ system, in particular of the drive system, are presented.