Emittance growth in linear accelerators

Factors affecting emittance growth in linear-accelerator applications requiring high beam quality and low in-machine beam losses are explored. A generalized method is developed for matching the average properties of an arbitrary particle distribution to an accelerator structure in the presence of space-charge and other perturbations. The effects of the particle distribution and the accelerator parameters on the preservation of input emittance and other measures of beam behavior are investigated, to study optimum performance under carefully matched conditions, and to show the degradation of performance in the presence of mismatch, steering, and other errors. The concept of detailed matching invoking desirable correlations is discussed briefly.