The Light of the Atom Bomb

Abstract

The primary reason for measuring thermal radiation from nuclear weapons is to evaluate the hazards associated with the heating of exposed objects. These hazards include cutaneous burns in humans, flash blindness, retinal burns, heating and subsequent weakening of wings and cortrol surfaces of aircraft, and the ignition of kindling fuels such as those that helped produce the great fire at Hiroshima. Studies on these effects call for detailed information on the thermal radiation, including its spectral distribution, the irradiance history and the total energy as a function of distance, weather, and other factors. Rough scaling laws, that relate the diameter and power temperature of the fireball with the time and yield, make it possible to predict thermal radiation damage for a wide variety of conditions. These laws are based on data accumulated from weapons tests during the period between 1948 and 1958. Data are presented graphically on the luminous efficiency of a nuclear fireball in air with a comparison with other familiar light sources. Comparison is also made between the light from a fireball and light from the stars and from the sun. (C.H.)