  Several high efficiency, low cost, RF sources are in development or recently
completed. All are designed to provide operating efficiencies exceeding 80% and
provide more than 100 kW of output power with a focus on high average power or
CW operation. The sources include (1) a magnetron system with amplitude and
phase control, a multiple beam, power grid-tube based source, a multiple beam
inductive output tube, and a klystron using the core oscillation method. The
estimated cost for the magnetron system and multiple beam power grid-tube
source are one dollar per Watt and 75 cents per Watt, respectively. Operating
frequencies span the range from 300 MHz (power grid tube) to 1.3 GHz (magnetron
and klystron). This paper describes the basic operation of the sources,
indicates the status and schedule, and provides available experimental results.
