Method for automatically setting an operating point given signal curve measurements with a particle beam measuring apparatus

Claim 1

In a method for automatically setting an operating point given signal curve measurements with a particle beam measuring apparatus wherein primary particles impinge on a measuring location, an energy shift of secondary particle being triggered at the measuring location and being measured with an opposing field spectrometer, and an opposing field of the opposing field spectrometer being set via a feedback circuit to a predetermined rated value for a specific reference potential at said measuring location, wherein an improvement comprises the steps of: prior to measurement of time-dependency of signals on the specimen (a) applying a periodic signal curve to said measuring location given stroboscopically keyed primary particles, said periodic signal curve also having a defined reference potential in addition to other potentials; (b) varying a keying phase of said keyed primary particles with respect to said periodic signal curve; (c) at least partially qualitatively registering the periodic signal curve; (d) determining a phase point of the qualitatively registered signal curve which corresponds to said defined reference pontential at said measuring location; (e) setting said keying phase of said keyed primary particles to a phase point of said periodic signal curve wherein said defined reference pontential is present at said measuring location; and (f) during setting of said operating point, keeping this keying phase at such phase points so that said reference pontential is present at said measuring location.