ed at American Chemical Society, 132nd Meeting, September 8-13, 1957. Ie mee Farlow, N. H.; Schell, W. R.3 and Adams, C. E. NATURE OF RADIOACTIVE FALLOUT PARTICLES. Paper present- New York, , The chemical composition, structure, and mode of origin of several different types of radioactive fallout particles have been determined using petrographic techniques, reagent films, and x-ray diffraction analysis. The fallout particles studied were collected following the detonation of nuclear weapons under various conditions at both the Nevada Test Site and the Eniwetok Proving Ground. Radioactive fallout particles were formed by the interaction of the condensing vaporized metals and fission products derived from the bomb and associated structures with the surface material swept up into the cooling fire- ball. Descriptions of the warious types of fallout particles are given and their modes of origin are qualitative- ly related by a simplified thermodynamic treatment. 31. Franzen, L. F.3 Myszynski, G.3; and Wiesenack, G. DOSES OF RADIATION FRON NATURAL AND ARTIFICIAL RADIOACTIVE SOURCES. (In German). Atomwirtschaft, 2, 362-6 (1957). Only since quite recently has man been subjected to irradiation which, as the result of medical and industrial development has been added to the radiation from natural sources. According to the investigations quoted artificial radiation accounts for 20 to 25 per cent of the total radiation le 31. Atomic test explosions have so far only made an insignificant contribution. The same can still be said of the industrial application of nuclear energy which is still in its infancy. It has been estimated that people living in Europe will over a period of 30 years be subjected to a total dose of radia- tion from 2,500 to 4,000 mr. Of this total dose received in 30 years about 750 to 850 mr will be contributed by medical and industrial appurtenances, the overwhelming share of 600 to 700 mr being the result of medical x-ray diagnosis. The atmospheric radioactivity has been estimated (incl. rainfall etc.) at 20 to 30 mr over a period of 30 years and will therefore not represent any hazards as far as external, direct radiation is concerned. The possible absorption by and accumulation of radiation substances in the body must, however, be carefully studied and special consideration must be given to fission products with a long half-life. 10 + Ware a at REY SL SIREN VIR ETEYH Mee 30.

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