Testing of detector strategies in scanning electron microscopy by isodensities

SUMMARY The dependence of the video signal of secondary electrons (SE) and backscattered electrons (BSE) on the local tilt angle φ and azimuth angle χ is important for the interpretation of micrographs and for comparing different detector strategies. The conventional Everhart‐Thornley detector (scintillator‐photomultiplier combination) has the disadvantage of collecting the SE with an efficiency which depends on too many geometric parameters of the specimen chamber. A more quantitative recording of SE and BSE can be realized by a multi‐detector system. For example, the signals A and B of two opposite detectors can be used to record the image with the difference signal A‐B or the sum signal A+B. Testing of these techniques requires a simple method of recording and comparing the dependence of the video signal on φ and χ for different detection modes and in different microscopes. This was tried by recording lines of equal video signal (isodensities) with a sphere as a test specimen.