To calculate the results as shown in Section 3.2.3, the following constants wre accepted as standard (Reference 6). Isotope Natural Abundance Half-life cl o, 3.3 x 107 5,720.0 years a 9.3 x 107 34.1 days 1.41 x 10° H3 ~- 12.4 years 1.06 x 1077 kK 1.12 x 10% 10.7 years 1.23 x 10° x,133 8.7 x 10% 5.27 days 0.91 x 1078 h, Min7! 2.30 x 10719 The following oackgrounds were chosen as being representative of the general test area; Isotope Background Atoms per Equivalent Mole Air cH 0,* 2.2 x 108 x8 Ast 2.0 x 1051 Essentially Zero KS Between 10° and 108 at 20,000 feet *These specific activities reported in los Alamos Scientifie Laboratory Report, LA~1102, as 180 and 0.03 dis/min. +Experimentally determined values based on unpub= lished data.ofHeadquarters, United States Air Forcei| } For LRD B-31 samples taken at 20 degrees to 30 degrees N latitude, values for x background are taken as 2.4 X 10° atoms per equivalent mole air. Methods used to compute atoms per equivalent mole air for a specific gas of a sample in accordance with separation and counting techniques are described in Reference 5. All isotopic quantities reported have been corrected for decay which occurred during the interval prior to assay. 30