Astounding Science Fiction, British Edition — page 69: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

DESTRUCTION FROM ATOMIC WEAPONS 6/ The Beta particle, having approxi- mately no mass and a negative charge, is a high-speed electron that can be stopped by a thin sheet of metal. Beta radiations in themselves can cause deep skin burns but in the air burst both the alpha and the beta particles have such a short range that they do not reach the earth. The final and most destructive form of radiation are the gamma rays which in reality are hard or high frequency X-rays. They cannot be stopped but only attenuated by material and have a range up to two miles. THICKNESS OF CQRICRETE (IN.) PERCENTAGE MORTALITY La Thepromptorinstantaneous gamma, occurring in the first few millionths of a second is produced during the fission process. Along with the fission, neutrons are captured by a nucleus of unfissionable material casing, et cetera, and thereby becoming excited. As the nucleus returns to ground state, it emits one or more photons of gamma. This prompt gamma accounts for some three per cent of the total energy liberated by the bomb. The delayed gamma, the most important form, comes from fission products emitting gamma in the pro- be Bes CECE ee Ree Pipeie et & 5 = shske’ ANCE pias sudden ZERO (¥F7.) (AIR BURST) Cconmicloooks.c©