L-Band Buncher/Modulator for X-Band Accelerator

Sem-Sol proposes to design and simulate an L-Band modulating pre-buncher that modulates an electron beam before injecting the beam into an X-Band linear accelerator. The user will feed a DC to 1 GHz signal into the modulator. The modulator will modulate a 75-250 mA electron beam with the signal and inject the modulate beam into the user’s X-Band RF linear accelerator. Sem-Sol’s design is based on the physics of a helical slow-wave structure as commonly found in traveling waves tubes. Sem-Sol will use conventional traveling wave theory and particle-in-cell computer simulation to design the buncher. Later Sem-Sol will build and test the buncher on an existing X-Band linear accelerator. Sem-Sol expects to achieve high instantaneous bandwidth (>20%), high capture efficiency, and pulse lengths of 3 microseconds. Sem-Sol expects that the input signal will need to be less than 10 kW. The buncher will employ a periodic permanent magnet structure for beam confinement and focusing. It is anticipated the design will be scalable to S-band and higher.