3.. Conversion of counting rates to microcuries, Although the primary interest of this project was in relative activities, advantage was taken of these standards to calculate absolute activities, Since the neutron flux, weight of u235, and fission yields ly/ were known, it was possible to obtain for each fission product of interest a ratig of pe to c/m for each counter. The fission cross section of U°3> was taken as 575 barns. Except in the case of very long lived nuclides, counting rates were read from smoothed decay curves. These values were corrected to cero time, 100 per cent chemical yleld, zero added absorber, and standard tube and shelf, The corrections to zero added absorber were based E absorption curves measured in these Laboratories, Data for Ca ¥o79 were corrected for self-absorption and Self~seattersage errors introduced by neglecting these corrections for S Bali0, can CeVJ: are discussed in Section 5,1, The 2 and 3, zr95, The aluminum cards on which the samples were mounted provided infinite back-scattering,. For the gross activity measurements small aliquots of the dissolved samples were evaporated in glass counting cups, The counting technique was sinilar to that for the individual nuclides except that the various corrections were not attempted, Gross decay measurements from 110 to 200 days were performed on aliquots of the dissolved size fractions evaporated in small glass planchets, The counting was done with thin mica end window OM counters, The physical geometry of the system was defined by a hole in a 3/8 inch brass plate which minimized the contribution of side scattering, The total absorption between the sample and the sensitive volume of the counter correspended to about 6 mg/em?, The counting rates were corrected only for coincidence loss. Since absorption and scattering effects are more or less significant depending uponthe beta energies, the slopes of the gross decay curves cannot be directly correlated with the radiochemical composition unless these pertinent corrections ~ a ee have been MGAGSe 3.4.5 Quantitative Analysis As a result of the tremendous heat generated by the detonations, large volumes of sea water were evaporated and sodium chloride was incorporated inte the fireball. Bunney and Ballou 13/ concluded from a thermodynamic study that chloride ion would be the predominant forn of chlorine in the fallout, They reasoned that the strong electronecativity of chlorine would cause it to react et hich temperature with alkali and some other met3ls to forn chlorides, They do not consider chlorates 4nd perchlorates possible at high temperature, For further information with regard to formation ef the particles in the fireball ard their subsecuent history, the chloride ion concentra- tion was determined by the Volhard method 14/ in each size-fraction of the fallout, The calcium ion concentration for each size=fraction of the fallout was also Ceterimined by the method described by Treadwell and Wall is/. This procedvre involves the quantitative precipitation of 26 SECRET — RESTRICTED DATA