Design of a spiral inflector and transverse beam matching for K130 cyclotron at the Variable Energy Cyclotron Centre

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. (author)