(F factor of what concentration of fallout material may accwmlate in the ankle region by walking around an area. & concentration of fallout material on the ground that would result in ebout 20 roentgens maximum theoretical infinity gamms dose, if in contact with the skin would result in a bela cose rete to the basal layer of the skin of about 1/4 those indicated in the previous paragraph. - 40 = a SH aE ES tate Ste LO