lI. DEBRIS MEASUREMENTS AND INTERPRETATION T. B. Cook Presiding (A) The Behavior of Nuclear Debris from the Upper Atmosphere Rocket Detonations as Determined in the High Altitude Sampling Program J. P. Friend Isotopes, Incorporated Introduction In the planning of a program for sampling the upper atmosphere by rockets, it is instructive to examine some of the information on the behavior of nuclear debris in the high atmosphere which has been deduced from measurements made in the lower stratosphere using U-2 aircraft. Samples of stratospheric dust collected at altitudes between 30, 000 feet and 70, 000 feet during early 1960 contained nuclear debris which originated from the detonation of the high altitude rocket-borne hydrogen bombs (Teak and Orange shots) in August 1958. Inter- pretation of the results yields some general guide lines for the design of an upper atmosphere sampling program. The High Altitude Sampling Program has been described in detail elsewhere. 1,2 For the present purpose it is sufficient to say that HASP involved sampling of the lower stratosphere (up to 70, 000 feet) by U-2 aircraft equipped with duct samplers for collection of particulate material on fibrous filter media and impaction probe samplers for collection of particulate material on surfaces suitable for electron microscope examination. Concentrations of various fission product and tracer nuclides in the lower stratosphere were calculated from radiochemical analyses of the filters using duct air flow rates computed from flight data and in-flight duct calibration results. Particle size-concentration distributions were calculated using electron microscopy of the impaction probe samples combined with flight data and semi-empirical aerosol impaction theory. 3 Figure 1 is a photograph of a U-2 showing the sampling ducts and the mounting strut for the impaction probe, Detection of Teak and Orange Debris Debris from Teak and Orange should be characterized by the presence of rhodium-102, a large quantity of which was produced by Orange. A number of HASP samples have been analyzed for this nuclide andits distribution in the stratosphere during early 1960 has been delineated. The highest concentrations were found in the northern and southern polar stratosphere and somewhat lower concentrations were found in the high tropical stratosphere. Unfortunately there exists a large uncertainty in the estimate of the total amount of rhodium-102 produced and, in addition, the radiochemical data are difficult to interpret because of the presence of a long-lived (~5 year half-life) isomer of rhodium-102. Teak and Orange debris may also be detected in the lower stratosphere through analysis of cerium-144/ 144 90 strontium-90 ratios. In Figure 2 the average Ce /s r ratios have been plotted for samples collected 95