Design of Wien filters with high resolution.
The design of a compact high-energy resolution device based on a symmetrical double Wien filter is presented. An accurate version of the boundary element method (BEM) is employed to model the shape and behaviour of the filters very precisely. Using a direct ray tracing technique, we investigate the geometrical aberrations in the basic filter, in which dipole and quadrupole electric fields and a dipole magnetic field are present. The additions of a quadrupole magnetic component along with some slight modifications in the geometry produce a drastic reduction in the aberrations.
Martínez
G
G
Departamento de Física Aplicada III, Facultad de Física, Universidad Complutense, 28040 Madrid, Spain. genoveva@fis.ucm.es
Tsuno
K
K
D016477:Artifacts; D008854:Microscopy, Electron / Q000295:instrumentation*; D008962:Models, Theoretical