Vorrichtung mit geladenem Teilchenstrahl und Verfahren zum Steuern der Vorrichtung

A charged particle beam apparatus includes a field emission electron source, electrodes for applying an electric field to the field emission electron source, and a vacuum exhaust unit for keeping the pressure around the field emission electron source at 1×10−8 Pa or less. The apparatus uses electron beams emitted to have an electron-beam-center radiation angle of 1×10−2 sr or less, and uses the electric current thereof, the second order differentiation of which is negative or zero with respect to time, and which reduces at a rate of 10% or less per hour. A heating unit is provided for the field emission electron source, and a detection unit is provided for the electric current of the electron beam. The field emission electron source is repeatedly heated to keep the electric current of the electron beam to be emitted, at a predetermined value or higher.