Contrast in the transmission mode of a low-voltage scanning electron microscope |
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Authors: | U. GOLLA B. SCHINDLER L. REIMER |
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Abstract: | The contrast thicknesses (xk) of thin carbon and platinum films have been measured in the transmission mode of a low-voltage scanning electron microscope for apertures of 40 and 100 mrad and electron energies (E) between 1 and 30 keV. The measured values overlap with those previously measured for E (≥ 17keV) in a transmission electron microscope. Differences in the decrease of xk with decreasing E between carbon and platinum agree with Wentzel-Kramer-Brillouin calculations of the elastic cross-sections. Knowing the value of xk allows the exponential decrease ∝ exp(—x/xk) in transmission with increasing mass-thickness (x = ρt) of the specimen and the increasing gain of contrast for stained biological sections with decreasing electron energy to be calculated for brightfield and darkfield modes. |
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Keywords: | Low-voltage electron microscopy transmission mode contrast thickness biological sections |
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