. .- , 3 . -“ y/cm in units of Normally converty/sec -see to uCi or pCi for a specific isotope. Can change from activity per unit volume to activity per unit mass by multiplying by the soil density (g/cm3)* For Enewetak want average concentration in top 3 cm. In general, average concentration in top z cm, S:, is given by z J sf=~ St e ‘az dz = $ (1-e ‘az) (7) az 0, Combining Eq’s 6 and 7 leads to the final expression for the conversion factor used at Enewetak (s:/p) N P m/2 = (l-e ‘az) B ‘O ‘S az [f ,2 ‘ o R((3)’tan @ exp a + ‘/p)sps ‘ece -. in units of F] ph”sec ‘P/p)a a Ci/ Cps where B converts y/see to pCi for a specific isotope. -/ 1de ‘ Cl 1