CYCO and SIR: New tools for numerical and experimental studies of space charge effects in the isochronous regime

This dissertation describes two novel tools for numerical and experimental studies of space charge effects in the isochronous regime: the code CYCO and the Small Isochronous Ring (SIR).; CYCO is a multi-particle code capable of simulating intense beam in isochronous cyclotrons in an acceptably short period of time without using powerful multi-processor computers. While developing the code, we paid special attention to having realistic models: The code calculates trajectories of macro-particles in a three-dimensional calculated or measured magnetic field map, using the complete system of the equations of motion. It uses the particle-to-mesh method to calculate the space charge field of the beam.; When used for calculating the beam dynamics in the low energy part of the PSI Injector 2, CYCO yielded results similar to those predicted by the code PICN. The code was used to simulate the beam dynamics in the SIR. We intend to validate the code, comparing the results of the simulations to the experimental results that will be obtained later in the ring.; SIR is a small-scale, low energy isochronous ring. The ring provides a unique opportunity to perform accurate experiments on space charge effects that are difficult to conduct in large-scale accelerators because of resolution and power limitations imposed on beam diagnostics. The opportunity to do accurate measurements of beam parameters allows the ring to be used for code benchmarking. The results of the experiments will also have applications to isochronous cyclotrons and synchrotrons at the transition gamma.; The ring has been assembled and commissioned. The first experiments with the beam in the ring show that the ring parameters are close to the design values. The observed behavior of the 20 μA beam indicates a fast growth of the energy spread within the beam due to space charge effects. The corresponding growth of the radial beam size is similar to that predicted by CYCO.