‘') ri rrPrrp?rrrrerrrrrrttrtirsepertirtesefiteteeétit# \ 100 Ratio at t=O SS x\ E Zr95/cs'3" ACTIVITY RATIO \ 10 o High Altitude Shot + Pre-Hardtock i = r : NN Lo oO 3S 2 c 2 Lo @ C ® oO <q + — - <= @ ~~ C C — . ° “) rT | - eo Hardtack ~ 7 J - 2 - oO 7 X o & Oo . - C 7 X Pre-1958 L - - x - 0.0! Soviet October } C - 0.1 == x > eH Series Litistjftftt?tt tt Ei tt i t ttt tt | MAMJJASONDJFMAMJJASONOJFMAMJ J 1958 Fig. 7 -- The Zr ics! 1959 37 1960 activity ratio of Soviet October, high altitude, and pre-Hardtack radioactivity 123