20100187433 | IMPROVED PARTICLE BEAM GENERATOR - A particle beam generator comprising particle extraction means disposed adjacent a particle source and operable to extract particles from such a source into an extraction aperture of the extraction means to form a particle beam, particle accelerating means operable to accelerate the extracted particles to increase the energy of the beam, and focussing means operable to focus the particle beam, each of said extraction means, accelerating means and focussing means being arranged in sequence and having apertures therethrough and in alignment to define a passageway through which the particles are constrained to move, characterised in that the extraction means comprises a lens structure comprising at least a pair of electrodes separated by a layer of insulating material allowing the application of different potentials to each of the lens structure electrodes, one of said electrodes comprising an extraction plate having an extraction aperture formed therein, by means of which extraction plate particles may be drawn from the particle source and through the extraction aperture by means of a potential difference between the source and said extraction plate. | 07-29-2010 |