+ ere geet 3 aes 4: = =a Fractionation of Radiostrontium in Bomb Debris The two radioisotopes of strontium, Sr°9 am sr?are chiefly farmed by the decay of primary fission produsts according to the schemes, +. i: Ir 90 iB wh set: — i$ rm = 443 ae ELE tT tt cee Ty iid. b Rb90 rS9 neo? 256 5a” cy! it UNCLASSIGSED 4 Sr 90 ig i Short “Ete” ‘ ot 25 “TES58d It is therefore possible that the bulk of the radiostrontium uot be % of produced umtil the fireball has cooled below the solidifying p the fallout debris. If this is true, the relative amount of or 890 in the close-in fallout should not be as great as would be predicted from fission yields, and should also be quite sarah les This Hea been confirmed by measurements mide by AFOAT-1 (Sr5? most of the results of our own analyses. /Mo”" ratios# and by The extreme variability of our initial radiostrontium results Por fallout samples led us to question the precision of ow ohemical mpthods. As a test, three samples of firely powders4 Jangleite were by the same chemical procedure. The relative Sr°™ activity was found to be 2.6, 2,1 and 2.1%, compared with the theoretical value of 5, Teak abt of OF . Lf aticrt ated. te oe ee ge He ¥ This discrepancy may be possibly accounted for by considering tl hd The fallout samples run for radiostrontius were taken fran decey samples frow Tumbler-Snapper, Ivy and Upshot-Knothole. ith Ballou are given in Tables 4-6. [hy t+ some of the initial activity me induced, rather than fission prodwot activity. In any case, the precision of measurement is reascoable and igdicates that the wariadility of fallout radiostrontiiwm is real. stock of [These re- sults, along with the theoretical radiostrontium va luss from Bunter and Table 4 TUMBLER“SNAPPER PALLOUT rne Location Hanksville, U0 Date Initial d/e 5/26/52 137 sr®990 4, 9.6 108 74 106 114 120 Be 9. 16 12. 5. Average Theoretical 7.0 8.1 12.7 18.1 10.5 4.8 9.7 8.0 -19= —E=— 00131986 022 1097051