1.5 ESTIMATE OF MAXIMAL. SKIN DOSE FROM TUE GROUND In addition fo the total body patna dase, the very soft panima and fipher emery beta radiation front tle plane saqgree contributed to the skin dose. Further skut irradiation ce sulted tram local deposits of tatlout material on the body surfiiee itself, The Latter ts impos sible to estimate, but the fornter may be roughly attempted as follows. The bela dose rate in air ata herurht of 3 feet above the surface of in infimite plane contaminated with mixed 24-hour-old fission products is estimated to be about three times the ‘000 -- ee 9 " ‘ q 5O0 1 ’ : q ' DFRPTH D0O5t } Bod Q , IN) a PHANTOM MAN 8 4 —O— ENTIAL RADIATION a MON RESIDUAL FIELD ' ‘ > it ie 8 oO ‘ t 1m 3 > - ti Oo lod 200 1 a ' iT "4 |e' 4[ i a § ve} ‘ a ’ \ we ee Co de me cee é | b— . 50 -t. Oo 2boLL 10 20 30 DEPTH (CM) Fig. 1.5 Comparative Depth Doses in a Phantom Man of Initial Atomic Bomb Radiation and Radiation from ua Field of Fission Products gamma dose. The midline gamma dose is approximately 60 per cent of the portion of the air gamma dose due to 80 kv radiation or above. This portion in turn 1s estimated to be 90 per cent of the gamma dose measured in air by the instrument. Thus the dose at the surface of a phantom exposed to mixed fission product radiation from an external plane source might be expected to be 3, (0.6)(0.9) or about six times the midline dose, if both occur at 3 feet off the ground. Such a depth dose measurement has in fact been made experimentally at 2 previous