55. Lockhart, L. B.3 Baus, R. A.3 and Blifford, I. H. ATMOSPEERIC RADIOACTIVITY ALONG THE 80th MERIDIAN, 1956. 1957. U. S. Naval Research Laboratory. July, 15 pe Washington, Office of Technical Services. $0.50. PB131081. Measurements of atmospheric radioactivity and fallout at a number of sites along the 80th meridian (west) oe es,Se are reported for the year 1956. These results were obtained through the combined efforts of the U. S,. Naval Research Laboratory and the Meteorological Services of Chile, Peru, and Ecuador with the coope eration of the U. S. Weather Bureau and the U. S. Atomic Energy Commission. Radioactivity levels at the various sites during 1956 are reported for three different collecting systems: air filters, cloth screens, and gummed films. Extremely wide variations in the gross radioactivity of fission products in the air have been noted, with highest levels occurring in the Northern Hemisphere. The presence of some of the peaks of activity at various localities has been correlated with known atomic explosions. 56. Lockhart, Luther B. RADIOISOTOPES ON YOUR ROOFTOP. Education 34, 602 (1957). JournalofChemical Rain H20 and dry fallout were collected during a 2-week period by using a plywood platform (8 feet square) covered with 4-milpolyethylene (I). The material was passed over a column consisting of a leitnch band of filter paper pulp, a 2=inch band of cation-exchange resin, and a leinch band of anion-exchange resin in a piece of leinch (internal diameter) I tubine. Less than 2 per cent of the gross Beactivity passed through the column. The contents of the column were dried, ignited at 650°, and the ash was analyzed radio- chemically. Values for activity (disintergrations/ min., d./m.) and rate of deposition (d./m sq.ian, and atoms/sq,ft.coll: res 34 were, esPes per git 600, 13, 3.5 x 102 606, oe, 1.4 x 10 5369 7,000, 8, 8.7. x 169; vot: gh?’ 900, 25, 29x11 11,600, 13, 704 x 40°: sr 1,900, 2, 6.0 x» 107; 850, 1, 202 x 107; ott” BielY, "960, 1, 2x 107. 19

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