Advanced numerical and experimental beam dynamics investigations for the CW-Heavy ion linac HElmholtz LInear ACcelerator

Abstract

The HElmholtz LInear ACcelerator (HELIAC), currently under construction at GSI, has high beam transmission requirements due to the application of superconducting components in continuous wave operation, which can only be achieved by smart beam matching to the superconducting section. This work is mainly concerned with the injection into the superconducting HELIAC section, i.e., with the measurement and optimization of the beam transport and with the design of the normal-conducting injector linac. For this purpose, a reconstruction algorithm is developed in this thesis to calculate the parameters of the longitudinal particle density-distribution. Its implementation and practical application are presented, which is suitable for the optimization of both the current HLI injector and the future standalone HELIAC injector. Furthermore, a novel beam collimation system has been designed and put into operation, which will be used for beam-based alignment by means of a so-called pencil beam. Finally, the new design of the normal-conducting injector linac created in the course of the thesis is presented, using a drift-tube accelerator consisting of two Interdigital Hmode (IH) cavities with Alternating Phase Focusing (APF) beam dynamics. Special emphasis was placed on optimal beam characteristics. By minimizing the emittance growth along the drift-tube accelerator, and the consequent improvement of the beam brilliance, the performance of the HELIAC can be significantly improved.