SECRET CHAPTER 1 INTRODUCTION t.1 ORJECTIVES The objectives of Project 2.6b were to determine: 1. The variations in chemical and radiochemical composition of solid fallout with particle size, zero-point environment, and time and distence of collection, 2. The chemical and radiochemical nature of liguid fallout and base surge, if formed, 3. The manner in which gross decay rates are affected by variations in radiochemical composition. 1.1.1 Purpose The purpose of obtaining these data was for use in studying basic problems of fallout phenomenslogy. The ultimate objective of this and similar work js to chtain data which may be used to develop a theory for the prediction of the military effects of operaticnal nuclear weapons under svecifiec conditions. Data obtained to meet the first objective may be used to aid in the developrent of a model of fireball dynamics in relation to varticle formation. Liquid fallout was also studied to gzin further insight into the histery of the fallout materiel after its formation, and for documentation of internal radiation hazards. An investigation was carried out on the relation between decay rate and radiochemical cotposition because it appeared that 1t might be apolicable to the problem of predicting the decay characteristics of fallout material from any operational detonation. 3 SECRET RESTRICTED DATA