TABLE 3.1 ALTITUDE RADIATION DATA OVER LAiw (ENIWETOK ATOLL) Altitude mr/hr* mr/hrt mr/hrt mr /hr§ mr/hrf mr/hr** ft 1,000 800 "600 500 400 180 0.7 1.0 1.2 200 1.9 1.9 500 100 950 75 1,200 50 1.0, 1.1tt 1.5 1.8 18 5.7 2.8 300 ; ‘ 130 2.5 2.3 1,700 4.1 30 8.5 42 12.5 70, S5tt 18.0 11.0 * Mohawk + 2, over Tilda, scintameter TH-3, S/N 25 in helicopter. + Mohawk + 2, over Tilda, scintameter, TH-3, S/N 2 in helicopter. t Mohawk + 2, over Sally, scintameter, TH-7, S/N 3 in helicopter. 4 § Seminole D~day, over Janet, scintameter TH-3 in helicopter. 4 : € Mohawk + 1, over Janet, scintameter, TH-3, in P2V-5. ** Mohawk + 1, over Janet, Top Hat radiation detector in P2V-5. tt Values from repeat runs. gamma-emission energy that is considerably softer than the radium used in instrument calibra- tion, the sodium iodide detector should read high on an actual survey. The data in Table 3.1 were normalized to the theoretical curve, and are shown in Yigures 3.2 and 3,3, — & Seminoie D-Day-Scintameter -Over—-Janet © Mohawk D+2- Scintameter -Over- Sally Percent of 3- Foot Dose Rote DO Mohawk D+2- Average of 2 Scintameter-Over- Tilda 0 200 400 600 800 1000 Altitude , Feet Figure 3.2 Radiation attenuation over land (Helicopter). 1200 7 DCE ARCHIVES Table 3.2 summarized the data obtained over water, and these are plotted in Figure 3.4. Additional data of this type have been derived fron’ measurements made in previous operations. This information is presented in Appendix C. The curves in Figures C.1 and C.2 show a similar correspondence to the theoretical curves. 26 23