- oe BO CHAPTER |, GAMMA ENERGY-DOSE SPECTRUM bel PHOTON FLUX SPECTRUM The fallout material deposited on the ground produced a large area Pplene source of radiation. Before a total gamma dose could be calculated, it was necessary to correct the dose rate readings in air taken with the survey instruments with the meter response factors found to te necessary for different energy regions. Further, to estimate the distribution of dose with depth in tissue required a knowledce of energy distribution of the incoming flux in a given exposure geometry. _ Fora source as large as these fallout fields, this energy distribution will be a function both of the original source energy and the energy degradation effect of passage through intervening air, A method ef evaluating the latter, which was due mainly to Compton scattering in air for the fission product energy region, has been presented in Reference 7. This technique was employed here. Energy spectra of the CASTLE fallout itself has been measured with a scintillation spectrome- . ter on a series of cloud samples as early as H+ been published in Reference 8, days, The data have The preliminary data on the earliest of these, a 9h-hour-old cloud sample, were used in the calculations sun- . marized in Reference 16, These are given in Table h.1 (Reference 9). This 9h-hour sample from Shot 1 represents the closest approach to the ' | mee Renterie as one ay erone ' . waere et et _actual time during which the exposures occurred,