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 observed by him was that the activity and volume were proportional. number of granules in each size class was taken from Suito (Su56). at median activity was 370wm for Bikini Ash. gY ] yY QA gy CAA SG Z N (UA. jZY jj jj Zj jj Zj jjj j j ’WMl™™ NX % OF TOTAL ACTIVITY Nn S) o Yj ZY Y LASSI SA, ae ee ae ee | ee 20 The The size