PURPOSE: To lessen addition times for obtaining a detection signal to the analysis grid of an energy analyzer given to a deceleration electric field, by tilting secondary electrons, emitted from the radiation surface of the primary electric charge beam of a specimen, to the beam optical axis so as to be incident on the incident surface of the grid at an acute angle.
CONSTITUTION: Only a speed component (v), in a vertical direction to the incident surface of a grid 11, is acted in the case of secondary electrons 12 to function as a demagnetization magnetic field, so that they can be incident on the incident surface of the analysis grid 11 at an angle smaller than 90°, that is, an acute angle θ. Here, the component (v) can be represented as v0Sinθ, where v0 means the speed component in the progressing direction of the electrons 12. The whole energy W0 of the electrons 12 immediately before passing the grid 11 can be shown as (1/2).m.v02, where (m) means the mass of the electrons 12, and electron 12 energy W passing the grid 11 can be expressed in a next formula: W=1/2mv2=1/2 (v0Sinθ) 2=W0.Sin2θ.
ITO AKIO
ABE TAKAYUKI
