. gumme, to plaques containing different racioisoto;es. 8 Fertinent dats are abstracted as follows! Surface Dose Recuired to Iroduce Reoognisable Transepidermal isotope... Energy. Yttriun’+ Injury (Roentgen~equivalent— keel Estimated Amount of Radiation That Fene= trated Skin te A Depth Sreb) 1.53 1,500 1,200 Strontius? 0.61 Yttrim?% 2.20 1,500 1,400 The average waximum energy of the beta particles from fallout saterial varies with tiue but will be assumed to be roughly comparebie, in respect to depth dose, to Yttriux’> or sr??ny99, Since the gamua dose at a depth of 7 mg/cm vould not be significantly different from the surface gauna dose, the ratio of 130 te 1 for beta-gamma vill be esswned at the basal layer of the eptiderzis. {one experinent with sheep, using $r%¥90 plaques, shoved that 2500 reps at the plaques' surface produced ulceration in one but net another of two sheer.® On the other hand, 1000 rads delivered to tisouedepen ef 7 mg/ez” from a P32 one inch diameter aisleype of eninal not statea} produced tanning, prolonged erythems and deuquanation.*#] It is to be remembered that the above discussion was first based on gurfaes gamma dose rates whereas the monitors will be making their gama *"Comparative Study of Experisentally Produced Beta Lesions and Skin Lesions in Utah Range 5 . Lushbeugh, C.k., Spalding, JF. and Male, DB, Lash Wovexber 30, 1953 (UNCLASSIFIZD). #92We33068 A status report. Sept. 15, 1954 (COMFIDEMNTIAL). ro ta! ‘ £ FP ge Re a . ye QO