Variable pressure scanning electron

A nondestructive method may be applied to a sample with relatively simple composition, but for a more complex sample, digestion processes are recommended, which are destructive. Beam analysis is recommended as a nondestructive method for samples with simple composition. The reliability of the analytical information for the beam analysis technique is assured by reproducibility and homogeneity of surfaces. It is necessary to clean the surfaces before the analytical process. Also, there are mechanical steps used for sample preparation to assure surface homogeneity. Conventional scanning election microscopy (SEM) is widely used as an analytical tool.38 4(1 Variable pressure scanning electron microscopy (VP-SEM) opens new opportunities in the field of materials science. Samples such as liquids can be analyzed using the VP-SEM technique without any prior preparation method (e.g., the characterization of two-phase crude petroleum from the... 

Adamaik B and Mathieu C 2000 The reduction of the beam gas interactions in the variable pressure scanning electron microscope with the use of helium gas Scanning 21 178... 

The samples were examined by variable pressure scanning electron microscopy (SEM) with a LEO 1450 VP microscope (Zeiss, Oberkochen, Germany). 

On the other hand, the influence of the state of hydration on the photocycle of bacteriorhodopsin is remarkable. In order to study its effect, thin layers of purple membrane were prepared by drying concentrated suspensions of purple membranes in water on a glass sUde at room temperature and atmospheric pressure. Variable hydration of the thin layers was obtained by equilibrating the preparations with various relative humidities produced by saturated salt solutions. The average thickness of the preparation was 1-3 m as determined by scanning electron microscopy. The glass slide containing the preparation was inserted into a cuvette suitable for spectroscopy and equilibrated with the required specific humidity before analysis. 

Quahty control. The quahty of matrix deposition on ITO-coated glass is characterized by scanning electron microscopy of the surface. To avoid disturbance of the matrix layer, the SEM analysis is conducted without any additional coating using a variable pressure instrument see Note 9, Fig. 24.1a, b). 

Another method is automated serial sectioning of specimens with an ultramicrotome integrated into an environmental scanning electron microscope (ESEM). This method involves imaging the surface of the specimen after removal of each slice. The reason for the choice of an ESEM (or a variable-pressure SEM) is to avoid specimen charging. The experimental setup of such an ultramicrotome operating in situ within an ESEM is described in [16]. 

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