Process and apparatus for the elementary and chemical analysis of a sample by spectrum analysis of the energy of the secondary electrons

摘要

A process of elementary and chemical analysis of samples by spectrum analysis of secondary electrons emitted by the sample when it is subjected to a beam of monoenergetic primary electrons concentrated on its surface is characterized in that the intensity of a beam of monoenergetic primary electrons Ep emitted by an electron gun is modulated according to a sinusoidal law at a frequency omega , in that the secondary electrons of energy E emitted by the sample are collected, in that the intensity of the collected beam is detected by generating an electric detection signal proportional to the intensity, in that the intensity of the component of the frequency omega of the detection signal which provides the number of secondary electrons corresponding to the said energy is measured, and, in that the value of the collection energy E is modified in order to scan the energy spectrum comprised between the values E1 and E2 so that one obtains the spectrum n(E) of the intensity of the secondary electron emission of the sample as a function of the energy E.