Beam dynamics studies and the design, fabrication and testing of superconducting radiofrequency cavity for high intensity proton accelerator

Abstract

The application horizon of particle accelerators has been widening significantly in recent decades. Where large accelerators have traditionally been the tools of the trade for high-energy nuclear and particle physics, applications in the last decade have grown to include large-scale accelerators like synchrotron light sources and spallation neutron sources. Applications like generation of rare isotopes, transmutation of nuclear reactor waste, sub-critical nuclear power, generation of neutrino beams etc. are next area of investigation for accelerator scientific community all over the world. Such applications require high beam power in the range of few mega-watts (MW). One such high intensity proton beam facility is proposed at Fermilab, Batavia, US, named as Project-X. Project-X facility is based on H_ linear accelerator (linac), which will operate in continuous wave (CW) mode and accelerate H_ ion beam with average current of 1 mA from kinetic energy of 2.5 MeV to 3 GeV to deliver 3MW beam power. One of the most challenging tasks of the Project-X facility is to have a robust design of the CW linac which can provide high quality beam to several experiments simultaneously. Hence a careful design of linac is important to achieve this objective. Hfi ion is non-relativistic at kinetic energy of 2.5 MeV and its velocity changes very rapidly with acceleration in Project-X linac. Thus, the linac uses several types of accelerating structures which are optimized for different particle velocities to provide efficient acceleration. Project-X linac has evolved over recent years from pulsed version to continuous wave (CW) version, so cavities are designed for both of these versions using simulation approach. In the pulsed (earlier) version of the linac, there already exists a 11-cell, 1.3 GHz design of cavity. HOMs study of the cavity is performed and asymmetrical design of the end cell is proposed. Further, an alternate version of the cavity design based on 9-cell is also proposed.