• P. Beasley, O. Heid, T.J.S. Hughes
  Siemens AG, Healthcare Technology and Concepts, Erlangen

Air insulated Cockcroft-Walton (Grienacher) cascades have been historically used to generate high voltages for accelerating particles. This paper explores how this technology can be utilised through a system level approach to develop more compact accelerator configurations with much higher voltages and gradients. One such concept is presented that realises a 20MeV, 1mA tandem accelerator that has a footprint ~2m^2

• O. Heid, T.J.S. Hughes
  Siemens AG, Healthcare Technology and Concepts, Erlangen

The concept of a compact particle accelerator capable of delivering accelerating fields upto 100MV/m using a direct drive RF LINAC is explored. Such a machine consists of a succession of RF cavities with the RF power being supplied from a ring of solid state RF transistors placed around the cavity circumference. To achieve the required accelerating fields 3 core technologies are presented. (i) The solid-state transistors are used to drive the wall currents in the cavities so achieving a direct drive of the cavity. This allows unprecedented powers to be reached (>GW class) as well as enabling independent phase control of the individual cavities. Central to the implementation is the design of the RF drive consisting of distributed SiC vJFET modules delivering 750kA at 800V per cavity. (ii) A High Gradient Insulator structure is required to hold an electric field of >100MV/m. In contrast to a conventional HGI, the concept utilizes a vacuum insulated grading layer structure. (iii) A chopper and injection system allow the formation of proton bunches with a spatial emissivity <3ns and an injection field of up to 100MV/m.