Ty see ee FOREWORD This report presents the final results of one of the projects participating in the military-efiec: programs of Operation Hardtack. Overall information about this and the other military-effect projects can be obtained from ITR-— 1660, the “Summary Report of the Commander, Task Unit 3." This technical summaryincludes: (1) tables listing each detonation with its yield, type, environment, meteorological conditions, etc.; (2) maps showing shot locations; (3) discussion: of results by programs; (4) summaries of objectives, procedures, results, etc., for all projects: and (5) a listing of project reports for the military-effect programs. PREFACE Project 2.1 gratefully acknowledges its indebtedness to the following organizations and personnel for their contributions to the project: W.B. Lane, U.S. Naval Radiological Defense Laboratory, for the general concept and details he developed for collection of early-time decay samples. R.K. Fuller, Project 2.2, for implementing the collection and handling of the early decay sample in the field. ‘ Task Unit 6 of Task Group 7.1, for furnishing and processing the 1,700 film badges used for technical measurements. Personnel of Task Element 7.3.1.5, the Task Group 7.3 Decontamination Unit, who showed a high degree of initiative and cooperation in installing the film badges aboard ship, in sample recovery, and in sorting and handling the many film badges required. The officers and crews of the Task Group 7.3 Special Projects Unit, who manned the three target ships, for their frequent and cheerful assistance in maintaining support equipment, accomplishing repair and alteration work, and furnishing work parties when requested. F.K. Kawahara, Project 2.2, for much needed help in reducing the gamma-radiation data required for the final report.