Longitudinal density profile shaping using double dog-leg emittance exchange beamline

Abstract

A new method for the longitudinal current profile manipulation using a property exchange method is introduced to overcome shaping capability and quality issues of typical correlation based methods. The longitudinal current profile manipulation is mostly done by introducing a correlation with the transverse space or the longitudinal momentum space to the current profile via RF field, wakefield or dispersive sections. However, the correlation provides a control of longitudinal current profiles but restricts its manipulation capability and quality at the same time. The method introduced in this thesis relies on the emittance exchange beamline which exchanges the longitudinal and the transverse properties. The manipulation on the horizontal space can be directly converted to changes on the longitudinal space via the emittance exchange beamline. The method is experimentally demonstrated. A Gaussian-like current profile is successfully shaped to a triangle, rectangle and trapezoid forms and also converted to a two-bunch train. These results indicate the generation of arbitrary longitudinal current profiles. Also, all sources generating perturbations on the ideal profile are theoretically explored and their mitigation methods are proposed in this thesis. Especially, one of the methods adjusting the slope of phase space successfully minimized distortions on the profile experimentally when the slopes are close to theoretically expected values.