Magnetic field optimisation and study of beam dynamics in 50 MeV compact H^- cyclotron

Abstract This paper presents the design and beam dynamics analysis of a 50 MeV, 200 μA H - cyclotron, to be used for the production of proton rich Rare Ion Beams (RIB), applications in fundamental scientific research and medical isotope production. A simple method based on analytical formulations has been used to find out initial parameters of the cyclotron including peak magnetic field in the magnet sector for a chosen orbital frequency. The sector geometry of the cyclotron is optimised using a linear interpolation method. This produces highly accurate isochronous magnetic field, ensuring perfect isochronism and stable particle acceleration throughout the cyclotron. The optimised sector shape has been achieved with only three iterations using this method. The static equilibrium orbit properties namely frequency error, integrated phase excursion and betatron tunes have been thoroughly analysed using equilibrium orbit code. Beam dynamics simulations including the effect of space charge have been performed along the accelerated central orbit and the maximum beam current that can be accelerated through the available aperture of the cyclotron has also been estimated.