Dispersion of Latent Image Specks in Silver-salt Photographic Materials Formed by Exposure to an Electron Beam with Constant Energy

The system used to analyze the process of the formation of latent image specks (LISs) in silver-salt photographic materials due to radiation exposure to obtain the dispersion index, which is the number of LISs in a silver halide grain formed by one impact of high-energy particle, was improved. By using the electron beam from a transmission electron microscope, electrons of uniform energy could be produced for irradiation purposes. The number of electrons impacting a single silver halide grain along with the energy of each electron was controlled by varying the current density and the applied voltage. A new analysis method which included the probability that LIS may not be formed despite an impact of high-energy particle was proposed. The number of LISs was counted by the arrested development method. The probability and the dispersion index were estimated at approximately 0.5 and 1, respectively, for an unsensitized emulsion with cubic grains. This method will be useful in the design of new nuclear emulsion plates.