This paper describes the design of a spiral inflector for inflecting heavy ion beams into the existing central region of the K = 130 Variable Energy Cyclotron at Kolkata. Simulation results of transverse beam dynamics through the spiral inflector and the effect of the fringe field on beam phase ellipses at its exit have been discussed in the absence of space charge effect. We have also made an effort to minimise the effect of inflector fringe field by properly adjusting the inflector voltage. The proper matching conditions in the central region have been obtained by optimising the system parameters of the existing axial injection line of K130 cyclotron. The tracking of particles that belong to the boundary of the optimised phase ellipses at the matching point has also been carried out in the computed electric and magnetic fields in the central region. Simulation results confirm that the optimised beam condition reduces beam losses for further acceleration in the cyclotron.

This paper describes the beam transmission characteristics through the spiral inflector and in the central region of the K500 superconducting cyclotron at VECC due to solenoid magnet misalignment in its vertical injection line. The equations of motion for a particle in misaligned solenoidal channel are derived from the Hamiltonian and used to investigate the behaviour of the beam during injection where the axial magnetic field of the cyclotron plays an important role. We have optimised the solenoid strength in the vertical line to reduce transmission loss in the spiral inflector and to match the beam in the central region of the cyclotron. The percentage of the accepted particle in the spiral inflector and in the central region are calculated for different values of translational and rotational misaligned parameters of the solenoids. The allowed tolerances of these parameters are obtained to get the desired injection efficiency.