fi ese 1000 — ORIGINAL SOURCE SPECTAUM WNEINITE PLANE 3 EN Ale FF T T x2 T 1 T = 7 | _ r DEPTH DOSE IN PHANTOM MAN, 500 e— INITIAL RADIATION ' ~*~ RESIOUAL FIELD ! = : \ % Oo a 1 ° x E t ww ; : ~_ 6 Hood 130 ENERGY (KEY) ~— = - ~— ec & al a a Le [~ ~ 20 _ 10 0 1 L 10 l 1 l 20 DEPTH (cm) L 30 Fig. 2. Comparison of depth dose curves in phantom man of initial atomic bomb gamma radiation and gammaradiation from a planarfield of fission products deposited on soil after an experimental nuclear detonation. Doses are expressed as percent of 3 cm dose. Gy. They had better protection due to their metal housing and since they showered and put on 200 clothes, the b less. Upon a one would m the magnitud term change: torical or pre Marshallese nel, Accorc Marshallese set up as she Figureleukocytes < time after ex shown by : counted. Tt cyte count count. Duri was No sigr count. Com there was 42 days aft Steady incre that of the - TOTAL DOSE IN AIR tr} LEUMOCYTES ANO NEUTROPHILS + 1O"" a EVACUATION AT 51 MOURS4 35 TIME (WR) a0 Sr mar PLStne PMa ewe AO miles with shorter distances for the higher isodose curves. A few miles north or south of the 2.0 Gy line would have placed people into the lethal range. These doses are estimates of what would have accumulated over a 48-hour period without shielding. The dose from which survival is unlikely ts in the vicinity of 8.0 Gy, below which lethality may occur at doses as low as about 2.0 Gy. It is fortunate that persons on Ailinginae, Rongelap and Rongerik were just outside the 2.0 Gy isodoseline. Fallout was observed on Rongelapatoll and described as snowflakes. On Aijinginae and Rongerik atolls it was described as mist. On Utirik it was invisible. The spectrum of gammaradiation from the fallout material showed peaks at 100, 700 and 1500 keV (Fig. 1). The two 1 geometry of exposure from the fallout field resulted in a very uniform depth dose with escalation of the absorbed dose in the first 1-3 cm at the surface of the body from the beta and low energy gamma componentsof the fission products, the surface dose being about eight times the 3 cm dose (Fig. 2). The absorbed dose rose continually to the time of evacuation about 51 h after the detonation on Rongelapto about 1.8 Gy (Fig. 3). There were three groups of Marshallese and one group of American military personnel exposed (Table I). The absorbed dose in the Marshallese on Rongelap was revised to an average of 1.90 Gy [3]. The Marshallese on Ailinginae received about 0.80 Gy and on Utirik about 0.14 Gy. The American military personnel received about 0.78 American Coa “ be wl Fig. 1. Histogram of degraded energy spectrum of gamma radiation from a 4-day-old fallout field produced by Comptonscattering at level of infinite plane 3 feet in air above uniformly distributed field. Unirik s oc Rongerik U.S a goo Ailinginae » aaa Rongelap Marshallese ¢ : o 200 Table I. Expo nN PERCENT OF TOTAL DOSE J — T TTT Fen T Cronkite/Bond, 8 eee oti Effects of Fallout Radiation on Human Beings 50 Fig. 3. Total cumulative dose in air from beginning of fallout at about 4-5 hours after detonation to evacuation at 5] hours post-detonation on Rongelap. Fig. 4. To Marshalle: population