Gigatron

The gigatron is a new RF amplifier tube designed for linac (linear accelerator) collider applications. It employs the lasertron concept in which a bunched electron beam is extracted from a modulated cathode and accelerated through a DC diode structure. The resulting beam is fully modulated at high energy without the requirements of a modulator or drift region that characterize all conventional amplifier tubes. RF energy is then extracted from the beam in an output coupler. Because there is excellent bunching of the beam current, very high efficiency can, in principle, be achieved. Three design features permit extension of the lasertron concept to very high frequencies. First, a ribbon-beam geometry mitigates space-charge depression and facilitates efficient output coupling. Second, a traveling-wave output coupler is used to obtain optimum coupling to the ribbon beam. Third, a gated field-emitter array is employed for the modulated cathode. A prototype device that is currently being developed is discussed