Principles of Scanning Electron Microscopy

This lecture discusses the principles of scanning electron microscopy at high specimen chamber pressures, focusing on wet specimen techniques, differential pressure limiting apertures, and vacuum system modifications. It covers the mechanics of protecting the electron beam from high pressure, the design of pressure limiting apertures, and the characteristics of the vacuum system. The lecture also explores the effects of different final aperture diameters on chamber pressure, the conductance of the system, and the implications for electron optics columns. Additionally, it examines the microstructures of magnesium hydride catalyzed with Ni nano-particles or Nb2O5, detailing the micrographs, X-ray diffraction, and X-ray absorption spectroscopy measurements.