A Quick Change Axial Cold Cathode Ion Source

An axial cold cathode heavy ion source has been built and successfully operated on the Michigan State University Cyclotron. This ion source was designed to minimize the time to change cathodes and thereby increase the cyclotron efficiency. The ion source change time (i.e. the time to change the cathode and restrike the arc) can be less than 15 minutes. In particular, all source parts that need to be cleaned at the end of a source lifetime are easily removed and clean pieces substituted. No internal ion source vacuum and water seals are broken. The ion source operates at gas flows less than 1 cc/min. and typically at 1/2 cc/min. This reduced gas usage results in a good accelerating chamber pressure and small attenuation of the accelerated beam to the external beam stop. The external ion beam intensity for a given particle and charge state are comparable to the intensity obtained from Oak Ridge and Berkeley.