Using the Orbit Tracking Code Z3CYCLONE to Predict the Beam Produced by a Cold Cathode Pig Ion Source for Cyclotrons under DC Extraction

Experimental measurements of the emittance and luminosity of beams produced by a cold-cathode Phillips Ionization Gauge (PIG) source under dc extraction are presented. (The source being studied is of the same style as ones used in a series of K250 proton cyclotrons for cancer therapy.) The effect of source aperture shape, and plasma arc current on luminosity are discussed. The concepts of ‘plasma boundary’ and ‘plasma temperature’ are developed as a useful set of parameters for describing the initial conditions used in computational orbit tracking. Experimental results for r-pr and z-pz emittance are compared to predictions from the orbit tracking code Z3CYCLONE with results indicating that the code is able to predict the beam produced by these ion sources with adequate accuracy such that construction of actual cyclotrons based on these measurements can proceed with reasonably prudent confidence that the cyclotron will perform as predicted.