Microwave ion source and injection system for a high current compact cyclotron

At the Variable Energy Cyclotron Centre, we are developing a 10 MeV, 5 mA four sector compact proton cyclotron. The main aim of this project is to study and settle various physics and technological issues associated with the production, bunching, injection, acceleration and extraction of the high intensity beams. A 2.45 GHz microwave ion source will produce protons beam 80 keV. The extracted beam will be first collimated by slits to remove the undesired components (H2+, H3+ etc.), bunched using a sinusoidal buncher and will be injected axially in the central region of the cyclotron. A spiral inflector will place the beam on the proper orbit. Two delta type resonators, each having ∼ 45 degree angle located in the opposite valleys, will be used to accelerate the beam. Finally, this beam will be extracted using an electrostatic deflecting channel. Microwave ion source and injection system of the compact cyclotron have been designed, fabricated indigenously, installed and commissioned. Presently it is under testing for beam characterization and inflection study. We have already extracted 8.5 mA beam measured at the DCCT and a well collimated (1cm x 1cm slit) beam of 6.4 mA at 80 kV at the faraday cup 3 m away from the source. This beam will be first bunched using a sinusoidal buncher and then injected axially in the central region where a spiral inflector will place the beam on the proper orbit. We have already installed a small dipole magnet, vacuum chamber with spiral inflector and few diagnostic elements. A study on the inflection of the high current beam has been taken up. The fabrication of the sinusoidal buncher is near completion. In this paper we present the recent simulation studies on space charge dominated beam transport, bunching and inflection. The operating experience and current status of the microwave ion source and low energy beam transport system will also be discussed. (author)