Highly Phase-Stable RF Power Circuits for the MIT-LNS Linac

The RF design objective for the MIT medium energy, high-duty-cycle linear accelerator has been to optimize and extend existing technology to obtain a degree of phase stability not previously achieved with high power RF systems. The RF system, which operates with a maximum average RF power of 80 kW per high power klystron (4 MW peak at 2% duty cycle to 1 MW peak at 6.5% duty cycle), is described. Accurate phase bridge measurements on the system indicate a pulse-top phase stability of better than 10 at 2856 MHz.