The importance of inelastic scattering in biological electron microscopy has been under-rated with respect to structural damage produced by the electron beam. Recently, semi-quantitative estimates of the beam damage associated with obtaining the micrograph indicate that the sturctural damage is severe. An improved theoretical description of inelastic scattering shows that the total inelastic scattering from carbonaceous material exceeds the elastic scatter by acout 3:1. This ratio is unaffected by acceleration voltage and no reduction in beam damage is expected from the use of high voltage (1Mev) for biological electron microscopy. The new calculations show also that over the wide angle scatter region (4Å to 1Å) the inelastic scatter is of approximately equal magnitude to the elastic scatter intensity. Hence, apertures, phase plates and collectors placed in this angular region intercept as much inelastic as elastic scatter.
Extension of the constrained ratio approach to aerosol retrievals from elastic-scatter and high spectral resolution lidars