Low voltage SEM LVSEM

The first corrected electron-optical SEM was developed by Zach [10]. Eor low-voltage SEM (LVSEM, down to 500 eV electron energy instead of the conventional energies of up to 30 keV) the spot size is extremely large without aberration correction. Combining and correction and a electrostatic objective lens, Zach showed that a substantial improvement in spot size and resolution is possible. The achievable resolution in a LVSEM is now of the order of 1-2 mn. More recently, Krivanek and colleagues succeeded in building a corrected STEM [53,M]. 

Recent advances in ultra high-resolution low-voltage FE SEM (HR-LVSEM) and extreme FESEM in catalysis... 

The image is formed by the signal of emitted secondary electrons, backscattered electrons. Auger electrons, absorbed specimen current (SC), or X-ray quanta, which modulate the intensity of a cathode-ray tube rastered in synchronism (Fig. 75). Conventional SEMs work with electron acceleration voltages of 5 - 30 kV, whereas a low-voltage scanning electron microscope (LVSEM) [222], [223] uses 0.5-5 kV. 

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