RESPONSE OF PHOTOGRAPHIC-EMULSIONS TO ELECTRONS IN GAS-PHASE ELECTRON-DIFFRACTION EXPERIMENTS

For a variety of commercial emulsions, the characteristics of response in vacuo to electrons have been studied. For Ilford N60 plates, experiments carried out at intervals over a period of several years showed that response has varied with time. Experiments in 1974 showed that batches of Kodak electron image, Ilford N60 and Ilford N50 plates had similar response curves. Recent experiments with Kodak electron image plates have shown how different development techniques and other factors affect the response. Significant differences in response are observed only when agitation during development is insufficient, and also when emulsions are not thoroughly wetted prior to development. The pre-soak gives rise to a more linear response. Response curves for optical densities D greater than unity follow variants of the one-hit theory. For the Kodak plates, whose uniform emulsions have similar response curves regardless of batch, the best fit of theory with experiment is for linear response to D=1.0, followed continuously by an exponential curve (equation (3)) to a saturation density of 4.3.