• P.K. Ambattu, G. Burt, M.I. Tahir
  Cockcroft Institute, Lancaster University, Lancaster
• P.A. Corlett, P.A. McIntosh, A.J. Moss
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire

Compact X-ray sources are integral parts of systems used in medical, industrial and security applications. The X-ray dose rate for a particular application mainly depends on the energy and current of the beam used to hit the target, usually made of tungsten. In applications that need higher penetration (100s of mm in steel), the beam energy needed is in the range of 1-5 MeV which can only be obtained using an RF linear accelerator. In order to reduce the size of the linac, higher RF frequencies (X-band) should be used while in order to reduce the overall bulk, RF focusing is employed instead of solenoidal focusing. Thus the main attraction of an X-band linac compared to a lower frequency version is the amount of lead required for shielding the system, and hence its weight. For capturing and bunching the low energy dc beam, a bunching section is needed in front of the main linac. The bunching cavity can either be a part of the main linac cavity or an independently powered section which can be used for certain specific applications as a shorter 1 MeV linac. In this paper, the design and simulations of an X-band buncher to be suitable for compact X-ray sources is presented.

• G. Burt, P.K. Ambattu, A.C. Dexter
  Cockcroft Institute, Lancaster University, Lancaster
• R. Calaga
  BNL, Upton, Long Island, New York
• E. Montesinos
  CERN, Geneva

Multipactor is a limiting factor in many RF power couplers. The SPL coupler is proposed to have a conical matching section between the window and the coaxial section however this section must be checked for multipactor. Multipactor simulations of the coupler up to a few MW's of power were performed using a variety of different codes and the results were compared. Simulations were performed in the conical and straight coaxial sections.