| The beam dynamics across transition region in a proton synchrotron is always an interesting topic. Because the Landau damping effect is weak during transition, the microwave instability will be a problem. In this dissertation, a simple scaling law is developed to describe the growth of microwave instability across transition. The comparison between the numerical calculations based on the scaling law and the measurement data on KEK proton synchrotron shows good match.; Due to the longitudinal space charge effect, the non-adiabatic synchrotron motion and synchrontron phase jump at transition crossing, in a proton synchrotron, the phase space ellipse of the beam does not match the RF bucket anymore after transition. As a result, the phase space ellipse of the beam will be tumbling. The tumbling can introduce the horizontal beam width oscillation, which has been observed on the booster synchrotron at Fermi National Accelerator Laboratory. In this dissertation, the method of RF voltage modulation is proposed to compensate such an oscillation. Both analytic computations and numerical simulations are done to prove this method.; The photoinjector is an important electron source that is able to produce ultra-short, high brightness electron beams for the 4th generation light source. In this dissertation, the theoretic and experimental studies of a photoinjector that were done at Argonne National Laboratory are discussed. |
