S =T <~10 100 r occurred within the first 15 minutcs a* downwind distances less than 16,500 feet for ilJahoo and 11,000 feet for Umbrella. In both shots the dosage due to deposited radioactive material on the ships and coracles was from light to insignificant. A study of the downwind pumma data showed that a distance of approximately 23,000 to 28,000 feet from surface zero should be nointainec in order to essure a total free-field dose of less than 25r. The High-Altitude Shots, Teak,Oran-e, and Yucca. Neutron Flux and Gamma Radiation Measurements. This participction for the Johnston Island part of the Operation 1s covere’ in the summary pertaining to Teak and Oranre, The measurements of the neutron flux-specio-um and total prompt-gamma= ray flux resulting from the detonation of stot ‘acco, IT an | altitude of approximately 90,000 fect was planned. Neutron time-of-flight measurements were to have been mode with an it scintillator-photodiode detector, from which determination of the e1ergy spectra of the neutrons could be made. A similar detector, usin> nzturc] Litnium (LiI), was included to provide correction data for the gamma resvonse of the detector. Two types of gamma detectors were uscd, 1. 2. .. CsI scintilletion detector. ... KBr crystal,-whose derkenin- wat neasured .s a function of time, 3 po. ao ose 8 All data were to have been recorded anc surcs-cuently telemetered to a recorde= ing ground station. The instrumentaticr wes contcined in a canister suspend= ed 2,750 feet below the nuclear device by ~.eans of a nylon line. Due to failure of the cormand transmitter, which controlled the canister operational functions, the instrumentation was inactiw at zero time, ana no deta was obtained. Profects Participting durine Developmental Shots. Neutron Flux Measurements. CO, be u Loco This was a prozram to document the neutron flux ye” ; PAGE , 4s” 2