Experimental Investigation Of Relationship Between Nonlinear Field Energy And Emittance Growth

Abstract : Understanding the phenomena of emittance growth in space-charge- dominated particle beams is important to any application that requires a small final emittance. Many researchers have looked at the process of emittance growth under these conditions. Wangler, et al., uses the idea of nonlinear field energy to describe emittance growth. In brief, a beam with a nonuniform radial intensity distribution has a potential energy associated with this distribution. As the beam propagates through a solenoidal magnetic field, this potential energy is turned into transverse kinetic energy and manifests itself as emittance growth. The experimental results shows that there is a relationship between the initial intensity profile and the tune ratio to the emittance of charged particle beams in solenoidal focusing fields. The results also agree with the predicted beam intensity profile changes under focusing for peaked and flat beams. This experiment shows that an experiment to verify this theory by using two different beam intensity profiles is feasible. More experimentation in this area is recommended. Keywords: Lanthanum hexaboride; Cathodes; Nonuniform radial intensity distribution; Electron gun. (aw)