spatial (horizontal) distribution in the nuclear cloud. lateral diffusion of the cloud. A correction is applied for For an increase in cloud area in direct proportion to time, the concentration of fallout particles is inversely proportional to time. The rate of deposition with time (T) is of the form: eT” 1 ,-a(T-b) 2 Parameters a and b are chosen to match the meter reading of 100 mR/hr at 7.9 hours and for the central 90 percent of the deposition to occur in 5 hours. The normalization to total deposition is provided by c. Fallout accumulated through time t is represented by the time integral of the above expression. The choice of the lower limit of integration is not crucial; the observed time of fallout onset is satisfactory. The complete expression for intensity with time is then: t 1, = 6271791? «3.09 ft 74 -1 ,--23(T-11.6) 2 dT Figure 2 depicts this relationship, which serves as the basis for the dose calculations. The peak intensity of 7 R/hr occurs at the end of the estimated interval of significant fallout (9 to 14 hours). (2) Personnel Activities on Rongerik Atoll, 1-2 March 1954 After being evacuated to Kwajalein, each person who was on Rongerik was interviewed to determine his specific activities during the period 1 March until evacuation on 2 March. Other pertinent data concerning their exposure conditions were also obtained such as clothing worn, food and drink consumed, and their recollection of what the fallout resembled. A synopsis of all of these interviews (Reference 3) is used in reconstructing the radiation exposure estimates in this memorandum. Seventeen of the interviews were in sufficient detail that the individuals' activities during the exposure period could be fairly well established on an hour-to-hour basis. For intervals without specified activities, reasonable assumptions are made that high-side the calculated radiation doses. example of the information available and reconstruct the dose for one individual. The Appendix contains an the procedure employed in order to