1.5 ESTIMATE OF MAXIMAL. SKIN DOSE FROM ‘FHE GROUND lnoaddition to the total body paamimia dose, the very soft gaminne and hipher energy beta raduution fron: the plane sources contributed to the skin dose. Further skin irradration ce sulfed from: local deposits of Tatlout nurternel on the body surface self, “Phe Latter is imps sible ta estimate, but the former may be roughly attempted as follows. The beta dose rate in air ata heyrht of 3 feet above the surface of an infinite phine conlaminated with mixed 24-hour-old fission products is estimated to be about three times the 1000 ;- - -- ee 8 ee ? a ‘ - i : t- q S004 Q 4 DERI DOSE IN PHANTOM MAN BI, ~——O— INITIAL RADIATION \ ' 1‘ wee] RESIDUAL FIELD ' ‘Oo a Oo mM ‘ ' a ' s a oO ' 5 200 4 1! a wv 5 4 > wt 1 fad a ‘ tu a i Oo 100 aee = (bewead ew wae 1 50 r—- = oo 10 20 30 DEPTH (CM) Fig. 1.5 Compariutive Depth Doses ini Phantom Man of Initial Atomic Bomb Radiation and Radiation from a 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 is 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 a previous