A Plane-wave-transformer Photoelectron Linac

We develop a novel photoelectron linear accelerator using a plane wave transformer (PWT) design [1]. In this design the input RF power is coupled to the accelerating cavities via a large concentric manifold cavity. The scheme makes possible very strong coupling between the accelerating cells, and relaxes manufacturing tolerances. The compact photoelectron linac integrates a photocathode directly into a PWT linac structure, and eliminates the drift space between a photoinjector and the linac which would otherwise lengthen the electron bunches. Using an emittance compensation scheme [2], the PWT photoelectron linac produces a high-brightness beam. We have demonstrated by simulations the feasibility of a 20MeV PWT photoelectron linac design with a set of eleven iris-loaded disks suspended and cooled by four water tubes inside a large cylindrical tank.