” ‘ ‘ awe : Ait a 3 : { ty So, . . ‘ we va . a 3 { #} . . L. vy : ; a- i 4 ~ my : . ‘ ‘ my . uo nee my , tog wi no wee os : - to te bs tern variations‘isince the atolls present a heterogenequs—exposure rete envirouoS e 4 A ment (Gr77). «| te: : a? . : Te » 7 dix Peay 4 rete wen, fh ; = External:exposure calculations are based ‘on Figures 24 to 26 which were derived: from data listed in Cr56, S8h57, Un59, and Gr77, t i line portions of the curve was-determined by) 3 x* | 1 The area under straight ws toe, (6) Rtn A n+} so} where bey i X = external exposure during straight line interval, mR, Ry = exposure rate at the end of the interval, gh, R, = exposure rate at the beginning ofthe interval, meh), Cy = time post detonation at the end of interval, hours, t; = Cime post detonation at the beginning of interval, hours, n slope of a straight line. = aw . , . Capen Data from 11 detonations during May, June, and July of 1958 (Sh57) indicated a mean Fallout deposition exponent of 18.8. This mean value was observed at Utirik, Rongelap, Parry, and Wotho and was applied to early time post detonation of BRAVO to obtain the initial increasing exposure rate history shown on aed Figures 24 and 26. s UN This method yielded a fallout deposition period of 5.5 hours on Rongelap and 12 hours on Utirik. This time compares well with the original observations reported by the Marshallese and by U.S. Navy personne} stationed in the area (Sh57). Initial dose equivalents on “acute doses" Bi oH Ah oS at im ey are developed in greater detail in another report. a “ 46 foo a ead Toron eeee eT ae eas ie rEg, diy pt ome gee sein Bott ead vig ra