CRLR - 112 - FALLOUT STUDIES ON ENIWETOK ATOLL. (Operation IVY) Edwin H. Bouton and Edward F. Wilsey, 2 March 1953. SECRET-RESTRICTED DATA Studies were made of fallout patterns, activity characteristics, particle size, and radiochemical content of airborne particulate matter - generated by the surface detonation of a thermonuclear device (Mike Shot) and the air burst of an atomic bomb (King Shot), These studies were made by sampling fallout with intermittent fallout collectors, trays, and Tracerlab Continuous Air Monitors. The studies revealed that: 1. Radioactive fallout continued for at least 6 hr after each shot, most of it occurring during the first 30 min. Fallout from Mike Shot was collected as far as 15 mi upwind from ground zero, while that of King Shot was collected up to 10 mi downwind from ground zero. Fallout activity did not vary in any regular fashion with distance from ground zero in either case. Some of the Mike-shot fallout was liquid. 2. The Mike-shot decay slope, as determined at all collecting stations, averaged -2.10 for the period between H + 190 hr and H + 500 hr. Decay slopes for King Shot averaged-0.67 for the period between H + 150 hr and H + 450 hr, 33 Preliminary results indicate that Mike-shot activities (108 to 1011 gisintegrations/min) were about 103 times the King-shot activities. Over 90% of the Mike-shot fallout consisted of particles one micron or less in size, but most of the fallout radioactivity was found in particles larger than 20 ux. The final report of this work appeared as CRLR-215 and WT-617. CRLR - 116 ~- OPERATING INSTRUCTIONS FOR RADIOLOGICAL SECTION OF MOBILE CHEMICAL LABORATORY, E4. M. A. Schmoke and F. A. Hedman, 5 March 1953. CONFIDENTIAL Functions of the Radiological Section of the Mobile Chemical Laboratory, El, include: (1) the detection and measurement of gamma radiation and beta radiation in various media; (2) the collection of actual and suspect radioactive material; (3) the confirmation of location and intensity of reported gamma radiation; and (4) the preliminary examination and evaluation of enemy RW protective material, protective equiprent, RW weapons, and munitions. The overall purpose of this laboratory section and its specially trained personnel is to help minimize the effects of enemy use of atomic bombs and RW agents. NRO Rel ATOM Sa