SLIDE 15 Granule size distribution and activity. The granule size distribution of Bikini Ash was used to estimate the time over which the bulk of the activity fell on the fishing vessel. Larger volume granules carried a major portion of the activity which fell at early times post detonation (La65). The Bikini Ash activity versus granule size distribtuion in % of total activity as a function of granule size was plotted here. In order to construct this histogram, the activity of a granule was assumed proportional to the 3.5 power of its size. Lavrenchik reported measurements varied such that the activity of a granule was proprotional to the 3rd or 4th power of the size (La65). A generalization WSS Z GY YY y ZZ ZYZZY JZ ZyJj] Z y ZZy XSGG SN S N IQQQ MX SSACG NN MMA MG % OF TOTAL ACTIVITY nN S a observed by him was that the activity and volume were proportional. The number of granules in each size class was taken from Suito ($u56). The size at median activity was 370um for Bikini Ash. F AU. 480 640 MEAN PARTICLE OIAMETER, um », —