| 摘要 |
PROBLEM TO BE SOLVED: To simplify determination of emission characteristics of a field emission source.SOLUTION: The state of an emitter can be determined by measurements of how the current changes with the extraction voltage. A field factor &bgr; function is determined by a series of relatively simple measurements of charged particles emitted at different conditions. The &bgr; function can then be used to determine derived characteristics of the emission that, in the prior art, were difficult to determine without removing a source from a focusing column and mounting it in a specialized apparatus. The relations are determined by the source configuration and have been found to be independent of the emitter shape, and thus the emission characteristics can be determined even when the emitter shape changes over time, without having to determine the emitter shape and without having to redefine a relation between the &bgr; function and the series of relatively simple measurements and relations between the &bgr; function and other emission parameters. |
