Stigmators are located in the objective and condenser lenses. Although diffraction can be useful, diffraction of electron waves around the aperture openings can interfere with the initial wave front. It is important to create a balance between reduction of spherical aberration and diffraction by selecting the proper size aperture. Image Formation A. Electron scattering is the interaction between the primary electron beam and the sample resulting in a change of energy or trajectory of the electron. Elastic scattering of the primary electron changes trajectory without altering it's kinetic energy.
Backscattered electrons are an example of elastic scattering.
Inelastic scattering transfers the kinetic energy of the primary electron to the atoms of the sample. Examples of inelastic scattering are Secondary electrons, Auger electrons, and Transmitted electrons. Secondary Electrons b. Auger Electrons c. Osmium Tetroxide 3.