PREFACE This report is intended to present the high lights of factual i:.formation obtained from this project's participation in Operation Castle. Detailed evaluation of the data is «inimized in this presentation; eu- phasis is placed on data presentation. Broed and intensive evaluation of the results of this report as related to the_gission United States Air Force, Washington 25, D. C.f other publications (Reference 1). . of Headquarters, are included in This report was prepared by the Office of the Technical Director, Headquarters, United States Air Force, Washington, D. C.-, under the overall command of Brigadier General Kooks and under the technical direction of D. L. Northrup. The conclusions as summarized in this report are based on the efforts of many individuals and organizations participating in this project. It is an impossible task to properly acknowledge each and every individual contribution to the efforts of this program; however, an attempt will be made to acknowledge some of the agencies and their key personnel who contributed to the overall success of the program. Personnel of AFOAT~-1 who participated in the planning, execution, and report preparation and review included; Dr. D. H. Rock, Dr. W. D. Urry, Lieutenant Colonel R. E. Heft, Captain D. N. Weiford, Captain O. J. Kvamme, J. W. Ponds, Major W. E. Scott, Major Robert S. Brundage, L. Sherrill, and Miss K. Harding. Captain F. F. Nicaise was officer-in-~ charge of gas sampling operations at Eniwetok. In addition, the pro- gram's success was greatly enhanced by the support given by many partic~ ipating branches of the United States Air Force and the United States Atomic Energy Comnission. Dr. R. W. Spence and members of his staff of the Los Alamos Scientific Laboratory (LASL), Los Alamos, New Mexico, and Dr. K. Street and his staff members of the University of California Radiation Laboratory (UCRL), Livermore, California, contributed to this program by mutual exchange of samples, analytical data and ideas. The assistance of Mrs. R. M. Ripley and Mrs. J. E. Kaul in the preparation of this report is gratefully acknowledged. The following laboratories and their key personnel contributed to the Castle program: : Tracerlab, Inc., Boston, Massachusetts: Technical Director, Dr. W. C. Peacock; rare earth radiochemistry, Drs. R. Epple, J. W. Shearer, and H. Petrow; gas separation and counting, Drs. I. J. Berstein, R. Epple, and J. W. Shearer; physical studies, Dr. J. W. Shearer and C. H. Sherman. Tracerlab, Inc., Berkeley, Californias: Technical Director, Dr. Lloyd R. Zumwalt; radiochemistry, Messrs. A. DeHaan, Jr., L. J. Beaufait, Jr., Leon Leventhal, and H. E. Menker. Argonne National Laboratory, Chicago, Illinois; Technical Director, Dr. Winston Manning; radiochemistry, uranium and plutonium, Drs. Sherman T. Fried and Gray Pyle; gas purification, Dr. F. T. Hagemann. 6