Patent Number: 
Section: claims

1. An adjusting device of an apparatus for generating a beam of charged particles, wherein said beam is for interacting with a target and wherein said adjusting device comprises:interface means for receiving, from a user of the apparatus, a set of desired values of characteristics of the beam of charged particles;means for determining a set of nominal values of adjusting parameters of the apparatus, corresponding to said characteristics of the beam of charged particles, and for passing said set of nominal values to the apparatus;means for continually or periodically measuring said adjusting parameters of the apparatus, and for computing corresponding values of said characteristics of the beam of charged particles; andmeans for determining, on the basis of the differences of said computed values from said desired values of characteristics of the beam of charged particles, whether a correction of said values of adjusting parameters is necessary. 2. An adjusting device according to claim 1, further comprising means for determining changes of said values of adjusting parameters suitable for restoring the desired values of said characteristics of the beam of charged particles. 3. An adjusting device according to claim 2, wherein said means of determining whether a correction of said values of adjusting parameters is necessary are also adapted for determining if operation of the apparatus needs to be interrupted, in the event of instability of said adjusting parameters. 4. An adjusting device according to claim 1, wherein said interface means are also adapted for informing said user when a correction of said values of adjusting parameters is necessary. 5. An adjusting device according to claim 1, wherein said characteristics of the beam of charged particles comprise at least one of the following: spatial resolution on the target, size of the particle beams, electrical current carried by the beam. 6. An adjusting device according to claim 5, wherein said adjusting parameters comprise at least one of the following: optical mode emission current of a particle source, width or standard deviation of a current distribution, energy of the particles, voltages applied to particle focusing lenses, amplitude of a scanning field, correction of stigmatism of the particle beam, a distance between the apparatus and the target. 7. An apparatus for generating a beam of charged particles, comprising an adjusting device according to claim 1. 8. An apparatus to claim 7, wherein said charged particles are chosen between electrons and ions. 9. An apparatus according to claim 7, comprising one of an etching apparatus and a microscope.