Appendix C ALTITUDE ABSORPTION MEASUREMENTS DURING PREVIOUS OPERATIONS Aerial dose-rate measurements above contaminated curve, except the Plumbbob gamma dose rates that areas have been abstracted from records of previous have been related to the surface measurement. weapon tests. C.l and C.2 are altitude plots for land and water, respectively. The agreement with the calculated attenua- These data include surveys over land contaminated with old and with fresh fission products, tion curve is within the limits of error imposed by altitude measurement and instrument calibration. A and surveys over water containing fresh fission products. Table C.1 single surface reading, i.e., 3-foot dose rate over contains data collected over land con-~ taminated with oid fission products, at the Nevada Test Site, between operations and prior to Operation Castle. TABLE C.1 Figures land, usually deviates markedly from the value pre- dicted from the readings at higher alutudes. ALTITUDE ABSORPTION MEASUREMENTS OVER LAND, OLD FISSION PRODUCTS ; Altitude t Absorption of Radiation oF ft pct mr/hr pet mr/br pet 3 50 100 200 400 500 800 100 —_ — 25 —_— 10 — 4.3 — —_— 0.79 0.56 0.40 0.11 57,128 —_ — 22 13.5 li 4 4.3 2.0 1.8 1.0 0.75 0.38 _— 50 40 36 22 15.5 8.2 — Thisisa — 3E * NTS, 1951, old shot site, scintilog TH-2, normalized from a series of ground and aircraft readings. ~ Janet Island, Eniwetok Atol!. prior to Operation Castle, e scintameter TH-3, P2V aircratt. t Janet Island, Eniwetok Atoll, prior to Operation Castle, scintameter TH-3, helicopter. DOE ARCHIVES During Operations Teapot and Plumbbob, careful function of the nonhomogeneous contamination on the measurements were made 3 feet from the surface, in small areas viewed close to the surface and the un- conjunction with simultaneous aerial measurements. evenness of the surface. Data abstracted from these surveys (Reference 12) are included in Table C.2. and Plumbbob (Table C.2, Nos. 2 and 3) data are hv-e? Fresh fission products in water volume were exam- The NTS (Table C.1, No. 1) on careful surface measurements, made by surves over an extended area and averaged; and the S-foot ined during Operation Wigwam (Reference 4}, and the value agrees with the predicted values. altitude absorption measurements are contained in Table C.3. over water are difficult to obtain, because a ship wili distort the radiation field. Data below 50 feet from sec All data have been normalized to the theoretical Meagsuremen'~ surface are not available. 66 Ge