TABLE 3.1 ALTITUDE RADIATION DATA OVER LAND (ENIWETOK ATOLL) Altitude mr/hr* mr/hrt mr/hrt mr/hré mr/hrd mr/hr** ft 1,000 1.0, 1.1tf 800 130 1.5 600 180 1.8 500 0.7 18 400 5.7 2.8 300 1.0 1.2 200 1.9 1.9 100 75 500 950 4.1 30 8.5 42 12.5 70, SStt :18.0 1,200 50 2.5 2.3 1,700 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. § Seminole D-day, over Janet, scintameter TH~-3 in helicopter. 1 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 calibration, 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 Figures 3.2 and 3.3. & Seminole 0-Day~Scintometer - Over -Janet 40 Mohawk D+2-Scintameter-Over-Sally O Mohawk D+2-Average of 2 Scintameter-Over - Tilda Percent of 3- Foot Dose Rate — ° 200 400 600 800 1000 1200 Altitude , Feet Figure 3.2 Radiation attenuation over land (Helicopter). Table 3.2 summarized the data obtained over water, and these are plotted in Figure3.4. Additional data of this type have been derived from 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