SLIDE 14 Comparison of Bikini Ash to unfractionated fallout. The per cent of fallout beta activity due to fission products present on day 26 after formation was tabulated. The hypothetical beta activity was based on a fallout composition which was unaltered due to chemical or physical mechanisms which affected certain fission product nuclides. This unaltered composition was referred to as unfractionated. This unfractionated fallout was calcylated from thermonuclear neutron fission data given by Crocker for U (Cr65). The comparison between per cents, based on the measured values of Bikini Ash beta activity and unfractionated fission product beta activity, required conversion of the Yamatera and Tsuzuki data sets (Ya56, Ts55) into percent fission product beta,actiyity. That is, we exclude the befg_activity of the activation products S, Ca and the 5ygnsuranic nuclide U for comparison purposes. It was assumped by us that U, which represented 20% of the beta activity on day 26 in the Tsuzuki results represented 20% of the beta activity in the Yamatera data. As previously implied, the term fractionation indicated alterations of nuclide composition in fallout debris. The ratio of two nuclides in fallout was often used to describe fractionation quantitatively (§r61)- The denominator of the ratio was taken to be the activity of “~Zr (Fr61). quantify fractionation between two nuclides, To the beta activity ratios were compared by Freiling (Fr61). The term “degree of fractionation” was used by him and represented the range of variability of the nuclide ratio. revi of Ja ese ults indi d to us that the activity ratios for 13270 132 Bf Pay Ce, ToerRh and Teacape (ratioed to measure 95 Nt beta activity) did not differ by a tor greater than abeut 1.5 from the unfractionated ratios. Ratios for 186 > er fy, BBecy, ro8s d 1435, differed by about a factor of 2, and Sr and 1 re, 29n6 differed, by about actor 3 re ive the rac nated fos. nuclides Y, tober Pane 185° 18200 ¥35r° Heecepe, [eae tnd17x 4 were in greater abundance relative to unfractionated debris. DAY 26 COMPOSITION OF BRAVO FALLOUT Nuclide ey ms Ss “Ca 271 22 Du (a) Greater Than Hypothetical "ty Ru, Rh, Te, 129mm MSD WINg Hypothetical Thermonuclear % Bikini Ash Neutron Fission, % Beta Activity Total Beta Activity 0.013 8.0 0.031 4.1 0.20 _ 0.0004 _ _ 0.05 20 — Less ThanHypothetical Sr, Sr, MY, Ba, M4073 Ru, 19 1, Approximately Same As Hypothetical 7, Nb,Te, MT, Ce, M4 Pr