body of air is infinite in extent and in equilibrium, then the energy emitted per unit volume must be equal to the energy absorbed per unit volume. If this air is a standard atmosphere, then the definition of the roentgen leads to the relation, 1 r = 6.77 x 10‘ Mev/cm’ from which 8.7 x 10! C E Mev/sec/m! being absorbed yields a field of 1,970 C E r/hr in a standard atmosphere. [If a medium has the same absorption and scattering coefficients per gram as the standard atmosphere, then the roentgen field is inversely proportional to density and is given by I= 1,970CE or p standard air p medium I = 2.54 <= (4.2) where [ is the intensity in r//hr inside of an infinite medium’of homogeneously mixed emitters, E is the average effective energy of the photons in Mev, C is the number of curies per cubic meter andtp is the density of the medium in grams per cubic centimeter. Figure 4.1 is a plot of the number of millicuries per cubic meter required to give a field of 1 r/hr versus altitude. This plot was cutained from Equation 4.1 in which the value for the TABLE 4.1 COMPARISON OF THEORETICAL AND EXPERIMENTAL ESTIMATES OF CLOUD ACTIVITY Source Total Phctons per Second Cherokee Zuni Navajo 7 minute Fromcioud profik s 24.51y%? 5.6 Theoretical | fiss. prod, 29.3 x 10% 7.69 x 10" 3.69 x 10” 1.07 x 10 v.13 ™ 10 pee". 4.7 * 10° x 10% _ 15 minute From cloud profiles fiss. Pp prod. Theoretical rts lox 10? 14.6 » 10? 3.7% 10% 3.7 «10 g.gexio% y.p4x 107 6.63 x 107 1,89 %« 197? v.12 x 10% " Activity due to the 0.07 Mev gamina from u** is on the border-~ line fer deteclion by the radiation transducer, and therefore the bulk of aetivity recorded arises from fissior products. energy was assumed to be 1.25 Mev and those for the densities were taken from Reference 6. From Figure 4.1 it is evidei.t that altitude is an important consideration in interpreting the information telemetered by rockets. The telemetered information tabulated in Appendix A is converted to millicuries per cubic meter as a function of range and altitude of the rocket by the use of Figure 4.1 and cornputed ‘trajectories. Figures 4.2 through 4.6 were prepared from this information by plotting rocket trajectories and drawing contour lines throuzh points of equal activity concentration, thus giving activity profiles through the clouds in the plan of the rocket trajectories. Since the usable parts of the trajectories were mostly through the portions of the clouds between the rocket launching point and ground zero, only this half of the profile is sketched. Figures 4.2 and 4.3 give the semiprofiles for Shot Cherokee at 7 and 15 minutes after detonation; Figures 4.4 and 4.5 give the semiprofiles tur Shot Zuni at 7 and 15 minutes after detonation; and, Figure 4.6 gives the semiprofile foc Shot Navajo at 15 minutes after detonation. The wind profile in the plane of the rocket trajectories has been computed and 1s shown on the 13-minute clouds. This line is a projection on the plane of the rocket trajectories of the vertical line above ground zero as it would have been distorted in 15 minutes by winds. It provides a means for visualizing the amount of shear to be expected in the clouds. 29