Radiation from High-Speed Particles

The theory of the weak visible radiation produced in a solvent by the action of gamma rays is discussed. It is shown why this phenomenon cannot be interpreted as luminescence. The radiation exhibited a property of extremely pronounced spatial asymmetry which lead to the theory that the radiation is produced by electrons which move uniformly in the substance with a velocity which exceeds the phase velocity of light in this medium. Angular distributions of the radiation intensity were determined for four liquids. The value of the angle was found to increase with increase in the index of refraction of the solvent. The measurement oi the intensity of the radiation by the proper electronic circuit is discussed. Applications of the radiation in particle detectors, in the study of broad cosmic showers, and in the measurement of energy are discussed. (C.J.G.)