A new extraction system for the upgraded AIC-144 cyclotron

This paper is a description of the computer simulation and the first experi mental results on an AIC-144 isochronous cyclotron new extraction system. T he cyclotron will be able to generate beams of protons, deuterons and alpha -particles. One of the principal goals of the upgraded facility is to extr act beams of protons and deuterons (proton energy 60 MeV, deuteron energy 3 0 MeV) for proton radiotherapy and for fast neutron beams. The precession m ethod for particle extraction was chosen as the best one. It is the first t ime that the proton beam of energy 35 MeV has been extracted from the AIC-1 44 cyclotron with an efficiency of above 50%. More careful adjustment of th e extraction system parameters (better control of the 1st harmonic of the m agnetic field and the position of the deflectors) will permit an increase i n the extraction efficiency to the design value of 70%.