Beam emittance calculation in the presence of an axially symmetric magnetic field

Shemyakin, Sergei Nagaitsev and Alexander

Fermi National Accelerator Laboratory

关键词: Magnetic Fields;    Beam Transport;    43 Particle Accelerators;    Electron Beams;    Electron Cooling;   

RP-ID  :  FERMILAB-TM-2107
RP-ID  :  AC02-76CH03000
RP-ID  :  754860

美国|英语

来源: UNT Digital Library

【 摘 要 】

The Fermilab electron cooling project requires low transverse electron velocities (both coherent and incoherent) in the solenoidal cooling section. One of the possible reasons for an increase of these velocities is aberrations introduced by optical elements in the axially symmetric portion of the beam channel (first of all, in the acceleration tube) preceding the cooling section. Most of these optical elements can be treated as thin lenses so that the aberrations can be characterized by an increase of an effective beam emittance as a function of the beam radius in this element. The goal of this note is to formulate a method that would allow to correctly estimate these aberrations in the presence of linear coupling and a non-zero longitudinal magnetic field at the cathode. This is of particular interest for electron beam simulation programs that are employed to optimize beam transport in the presence of a varying longitudinal magnet field.