time after detonation asd follows 0 aimpl- relationsiip, Fortier, tis ratio at any give.. tine after detonation has net teen fircly esta_lisced, One report™ sugcests the following data: Time after detonation Beta/cacce 72 hours 157/21 268 hours 56/1 These dais were o: taived from a cloud sample, ratcer t.an actual fallout material, a.d were a measure of surface dose o: @ plaque using a "dosincter~ type tetn-ray surface fonisation chamer," The metrod of collection surrests the possiility that the thicikness of material on the plaqies may be less’ than t-at to :e expected from the amount ef fallout trat would be of eoncern wien estimating proum ilities of beta turcs. 1s would reasvlt 42 a differest anmular dipiricutios of the vetas Influencing t:e -eta dose rate in the direction of a higuer value for the plaques, Anot-er reportl indicates a beta to gama ratio of 130 to 1 based on tieoretical comviations. A trird report® surgests @ redically lower ratio; however, there ma: be some dou! t as to its conclusions since tre fovisation cham er csed to measure gamzas only, t.ad a wall thickness of 1 mm eof sacelite sy TN which *,,, excluded a small part of the total rama dose presest, as well as @ large, tut unknown, fraction of the beta.* (‘the renee of 0,35 Mev tetas is about 200 mc/en® or approximately 1 oa of bacelite.) For our disoussicn here, we will assume a wpirface beta to gama ratio of 150 to 2, {AYO “Were In estinsting t:e |-eta dose to the basal laver of tie epidermis, one ma; refcr to tre work of “enrigues3. He exposed t e skin of ester tr tte pirs ef 1~20, Selentific Tirector's Report, Annex 6.5, “Interpretation of survejencicr fata.: co i "An Fstimate of the Relative Yasard of ‘eta and Garra iadintion from Fission Products". Sullivan, Filliam f, N°DL. April 19L9, CONFIL-NCIAL 2 UNP-37. Project L.7 "Garma~ eta Patio in the Fost-s ot Contaminated Arca", Jane 1953. CONFTT ONUIAL-RU TRICTID Pata. _ 3 "Effect of Beta Rea.s on the Skin As A Punch aay :e 'neres, Intensits, and Duratio: of ‘ OE/alA Radiatiow, Henriques, T.). Laboratory invesfipatio.. 2 © Vol. 1, Mo, 2, Sumner 1952.