Development of a 100 kW 2.815 GHz Continuous-Wave Elliptic Beam Klystron with Two Output Windows

At present, conventional circular-beam klystrons are used to drive accelerators at a number of DOE user facilities. Although sheet or elliptic beam technology makes it possible to operate high-power continuous wave (CW) devices at low beam voltages and high efficiency, important issues in the design of high-power, high-efficiency sheet or elliptic-beam klystrons still remain: how to design a high quality, high-power elliptic electron beam; and how to design an elliptic-beam klystron with an interaction circuit that will be compatible with the magnetic focusing system required to maintain beam quality. This project will develop an innovative, high efficiency, 2.815 GHz 100kW CW elliptic beam klystron (EBK) capable of operating at low voltages. Phase I will (1) prepare a concept design of the proposed elliptic beam klystron; (2) design an elliptic-beam klystron interaction circuit using small-signal theory; (3) design the elliptic klystron cavities; (4) perform 3D simulations of the elliptic electron gun, beam compression, and matching; and (5) development a template for 3D simulation modeling of the small-signal and large-signal elliptic-beam klystron interactions. Commercial Applications and other Benefits as described by the awardee If successful, the proposed design should facilitate the development of high-efficiency, high-power elliptic-beam klystrons. As a more efficient, lower voltage device, elliptic beam klystrons could replace conventional klystrons in new installations or upgrades. The market size of klystrons is about $200M/year worldwide. The annual worldwide sales of elliptic-beam klystrons are estimated to be $5-10M in 5 years and $20-30M in 10 years