f om to plaques eontaining different radioisotopes. | fertinent data are abstracted as follows: Surface Dose Recuired to Frodues Recognisable Transepidersal dectone. ‘Enarsy.s Yttrium’? 1.53 Strontius®? 0.6) Yttrium 2.20; The average Injury (Roentgen—eqiivalent- beta). Eetinated Anount of Rediation That FPene- trated Sria te A Bepth 1, $00 1,200 1,300 1,400 saximum energy of the beta partieles from fallout naterial varies vith time but will be assumed to be roughly eompsreble, in respect to depth dose, to Yttriun’* or Sr-Y9, sinee the gems Gose af a depth of 7 mg/cm would oct be significantly different from the surfase gemma dose, the ratio of 130 te 1 for bete-gamma vill be assumed at the basal layer of the epidermis. (One experiment with sheep, using Sr’0-190 plaques, showed that 2500 reps at the plaques’ surface produced ulesration in one but net encthar of DOE, NY two sheer.® On the other hand, lOOC rads delivered to tissue depth of 7 wg/on" fron a F“ one inch diameter aiskleype of anizal net states} produced tanning, prolonged erythens end deccuanat ion, **) Tt is to be remembered that the above discussion wes first besed on Surfags gemma dose rates wheress the sonitors vill be making thelr gam “"Cosparative Study ef Experiventally Froduced Beta Lesions and Skin Lesions in Utah Range . Lashbaugh, C.2., Spalding, J.P. end Male, BB. Lasl Novenber 30, 1953 (UNCLASSIFIED) . ##ie33068 a status report. Sept. 15, 10%, ‘CCHPIDENTIAL), a; + lg mre Lr 44d Baws