Electron Tracks in Photographic Emulsions

Abstract

Electron range. In a recent note¹, R. W. Berriman reported on a new photographic emulsion with which electron tracks can be recorded. Attempts have been made to relate energy and range of electron tracks in this type of photographic material, referred to as the NT2a plate. The electron tracks were obtained by exposing the plates to heavily filtered X-rays generated at increasing kilovoltages. The tracks were scanned under the microscope, and the number of grains of each track counted was plotted against the frequency of tracks. The curves so obtained show a shift of the maximum frequency towards greater numbers of grains with increasing kilovoltage. In a few cases where the tracks were at almost glancing angle to the plane of the plate, length measurements of the curved path of tracks were made. The maximum number of grains and lengths of tracks for each kilovoltage are shown in the accompanying table (columns 2 and 3).