50 THE SHORTER-TERM BIOLOGICAL HAZARDS OF A FALLOUT FIBLD THEORETICAL CALCULATIONS OF THE GAMMA RADIATION SPECTRUM, ETC. Figure 15 represents a typical small-yield bomb. The theoretical data represented by the “X” ’s conform amazingly well to the measured doses, symbolized by the circles. In the case represented by Figure 16 a very lowyield device wasfired, and the bomb parameters were such that the relative contribution of nitrogen capture gammas was small. For contrast, Figure 17 pertains to a case wherein nuclear parameters predicted an unusually significant nitrogen capture contribu- tion and a total gamma dose per KTof yield D = 2000 yda, Fler) Fieure 12.—Initial gamma differential dose spectrum at $,000 yards. pudding is in the eating.’ It would be desirable to have field measurements to support these predictions. Unfortunately, very little experi- mental work has been conducted to determine the spectrum of initial gamma radiation, except for some general and non-definitive conclusions to be drawn from absorption and depth-dose measurements. Although some field data based on photon-activated reactions of high energy threshold do attest to the presence of at least some very energetic gamma rays from nuclear detonations, it is difficult to check definitively the conclusions derived from the transport theory approach. However, one can compare theeretical predictions of total air dose with the well documented film badge gamma dose-versus-distance data from weapons field tests in order to determine in a general wayif the calculated spectra yield dose information that is consistent with the field data. Then, by inference, the spectral informa- tion leading to the total dose calculations would also be validated, COMPARISON OFINITIAL GAMMARADIA. TION CALCULATIONS WITH FIELD TEST DATA Figure 14 presents the air doso-versus- distance curve for the representative bomb configuration discussed before. The compo- nentsof total dose dueto fission product gammas and to nitrogen capture gammas are indicated separately, The composite dose is then de~ termined by adding these. For actual test nuclear devices, with known bomb parameters, specifie dose-versus-distance predictions can be made by the methods that have been dis~ cussed. These can then be corrected by con-~ ventional techniques to the appropriate atmospheric densities and compared with measured field data. Still the calculated points are acceptably close to the measured data. 1 O * 1000 yda great interest, but “. .. the proof of the 51 Elifev.) Fieurs 13.— Initial gamma integral dose spectra.