0018933 - - CHAPTER 1 INTRODUCTION 1,1 OBJECTIVES 4 ‘ . we + 4 GG The general objective of the project was to estimate, from analytical data on cloud samples, the relative distribution of certain radionuclides between the local and world-wide fallout formed by megaton-range detonations on land and water surfaces. Specific objectives were to: (1) obtain airborne particle and gas samples by rocket and aircraft sampling techniques; (2) determine the distribution of radionuclides between two groups of particles which differed from one another in their falling rates in air and which could be considered representative of local and world wide fallout; (3) attempt to determine an early-time distri- bution of radionuclides and particles between the upper and lower halves of the cloud and radially outward from the cloud axis; (4) estimate the extent of separation of fallout from gaseous fission products by fission determinations on gas and particle samples collected coincidentally near the top of the cloud at various times following the shots. SAN BRUNO TRC 1,2 BACKGROUND AND THEORY Data on the geographical distribution of fallout are particularly needed to assess the global hazards associated with the testing of nuclear weapons, — ,