Charged particle source with integrated electrostatic energy filter

A charged particle source with integrated electrostatic energy filter, the charged-particle source for use in a charged-particle apparatus, the charged particle source comprising:

• a charged particle emitter for producing a beam of charged particles along a first axis;
• a beam limiting aperture for selecting a part of the beam produced by the emitter, the beam limiting aperture positioned around the axis, thereby selecting an axial part of the beam;
• an energy selecting aperture in an energy selective diaphragm for selecting particles with a desired energy spread from the part of the beam that passed through the beam limiting aperture;
• electrodes for forming a focus of the charged particle emitter on the energy selective diaphragm;
• and
• electrodes for producing electrostatic dipole fields for deflecting the beam;
• wherein the electrodes for forming a focus and the electrodes for deflecting the beam are all arranged to be concentric with the first axis.