APPENDIX npn PROGRAM 6.0 — PHYSICAL TESTS AND MEASURMEINTS ~" . GENERAL 1. many physical The general objectives of this program were to determine about which relatively Littl effects and characteristics of an atomic bomb detonation or nothing was known before Operation GREENHOUSE. This information is not only use-— contributes mat— ful in planning future analytical and laboratory work, but it also | eriully to defense planning. CLOUD PARTICLE SIZE AND DISTRIBUTION 2, a, The objective of this part of the program was to ebtain data on the com position, concentration, specific activity as a function of particle size, and particle size distribution, of the particulate mtter in the radioactive cloud produced by an atomic bomb detonation, For this purpose, sampics of the atomic bomb cloud were collected during the period H hourplus 5 to 20 minutes at altitudes from 16,000 to 30,000 fect, This was accomplished by instrumenting vach of the twelve filter collecting B~17 drone aircraft with four types of apparatus for collecting of cloud samples, and for particle size separation of particulate matter; a snap sampler, an electrostatic precipitator, a cascade impactor, and a conifuge. b. The snap sampler operated satisfactorily and obtained an average of six samples per eight attempts for each of the three shots in which the project participated, The samples obtained are still undergoing detailed analysis by a civilian contractor and detailed information will be available in the final report, c, The electrostatic precipitator operated efficiently in slightly over 50% of the sampling attempts. Present data from these instruments indicate that the median diameter of the radioactive component of the cloud wes 0.8 micron, This ap. plics to BASY shot only, since the rest of the duta are still being studied, d. The cascade impactors operated satisfactorily and preliminary analysis of the samples obtained thereby for DOG shot indicated that the maximum activity was deposited on the fourth jet which has a calibration average particle diameter of 0.6 micron, It should be cmphasized that this is preliminary information. The cascade impactor samples appcar to be well suited for particle size and radioactive analysis, e@. The low sampling rate of the conifuge limited the usefulness of its samples on these tests. It is better adapted for conditions where dilute samples are nore desirable, weve DATA o_O RENEE HOT — ie ate poe Le .