Photographic Plates for Use in Nuclear Physics

Abstract

The registration of charged particles by the photographic emulsion is considered from the standpoint of their space rate of energy loss on passage through matter. On the basis of the highest-energy particles that can be recorded as recognizable tracks, an energy-loss value of 0.013 Mev per centimeter of air path is taken as an approximate threshold sensitivity value of the best present-day nuclear-particle emulsions. This energy-loss value corresponds to alpha-particles of energy >400 Mev, deuterons of 100 Mev, protons of 50 Mev, and electrons of 20 kev. Some evidence is cited to show that these limiting energy values are in accord with experience.