Chromatically corrected deflecting device for particle-beam equipment

A chromatically corrected deflecting device for particle-beam equipment, particularly electron-beam equipment arranged to irradiate locations lying in or in close proximity to a common or working plane which is oriented perpendicular to the axis of said equipment, wherein an electric deflecting field and a magnetic deflecting field are simultaneously employed for the deflection of a beam, the two deflecting fields being normal to each other and being oriented relative to each other in such a manner that the beam deflections due to the associated deflecting fields occur in one and the same plane, namely in the plane containing the undeflected beam, and wherein the electric deflection is at the same time directed in opposition to the magnetic deflection, and wherein the ratio of the magnitude of the electric deflection angle to the magnitude of the magnetic deflection angle remains at a constant value which is independent of the resulting total deflection angle and is chosen such that the chromatic aberrations affecting the deflections due to the individual fields exactly compensate each other with reference to their effect on the beam position in said working plane, the constant value of the ratio of the magnitudes of the deflection angles being uniquely determinable as a function of at least one of (1) the distance of the deflecting fields from the working plane and (2) the energy and rest mass of the particles to be deflected by particle-optical means.