same. The radiation environment was characterized in time and space, as were the activities and geometrical position of the individual. The rate at which radiation was accrued was determined throughout the time of exposure, from which the total dose was integrated. An uncertainty analysis of the reconstruction provided a calculated mean dose with confidence limits. The specific method used in a dose reconstruction depended on what type of data were available to provide the required characterizations, as well as the nature of the radiation environment. The radiation environment was not limited to the gamma radiation that would have been measured by a film badge, but also included neutron radiation for personnel sufficiently close to a nuclear detonation, as well as alpha and beta radiation (internally) for personnel whose activities indicated the possibility of the inhalation or ingestion of radioactive particles. Section 7.5, Reconstruction of Radiation Doses, provides detail on approach 3. 7.2 UNIT LOCATIONS AND ACTIVITIES. To determine the precise locations and activities of units and individ- uals that could have been exposed to the radiological environment, extensive use was made of historical records and reports, augmented by personal interviews where necessary to fill gaps in the archival material. profile of activities for each definable group or individual. The result was a The locations and activities of military units, whose operations were closely monitored and controlled by radiological safety personnel, were usually well defined. The same was true for observers, who were restricted to specific locations both during and after the nuclear bursts (as described in reference 1, for example). Ships’ locations and courses, with times, were usually known with a high degree of precision from deck logs. also usually well defined. Aircraft tracks and altitudes were Personnel engaged in scientific experiments often kept logs of their activities, noting times, locations, members of the party or crew, and unusual circumstances. Moreover, the locations of their experi- ments were almost always a matter of record, and the schedules of their early reentry times were often. documented. Where the records were insufficiently complete for the degree of precision required to determine radiation exposure, participant comments were used and reasonable judgments were made to further the analysis, such as was In every case, both the distance from the detonation 167 S done for reference 2.