Spectrometer objective for particle beam measuring system

摘要

Spectrometer objective for a particle beam measuring system with an objective lens and a retarding field spectrometer which form a particle beam optical unit for focussing a primary particle beam, wherein the retarding field spectrometer comprises an extraction electrode arrangement for extracting secondary particles from a specimen, an acceleration electrode arrangement for accelerating the secondary particles in the direction of the objective lens, a retarding field electrode arrangement for establishing a potential barrier which retards the secondary particles and means for charging the first electrode arrangement with at least two different voltages for adjustment of the extraction field strength. Furthermore, there are means for charging the acceleration electrode arrangement dependent on the voltage of the extraction electrode arrangement to form a secondary particle bundle being adapted for passing the retarding field electrode arrangement.