FOREWORD This report is one of the reports presenting the results of the 34 projects participating in the Military Effects Tests Program of Operation CASTLE, which included six tast detonationsa. For readers interested in other pertinent test information, reference is made to WI-934, Sum Report of the Commander, Task Unit 13, Programs 1-9 Military aifects Sogn “hia summary report includes the following information of posaible general intorest. a. An over-all description of each detonation, including yield, height of burst, ground zero iccation, time of detonation, ambient atmospheric conditions at detonation, etc., for the b. Ce de six shots. Discussion of all project results. A summry of each project, including objectives and results, A complete listing of all reports covering the Military Effects Tests Programe This report on close-in fallout studies at Operation CASTLE supersedes the preliminary report; ITR-916, which was issued in Vay 19546 ACKNOWLEDGEMENTS Many helpful suggestions in the planning and execution of this project were made by Lt Colonel Richard R. Entwhistle, Chemical Corps, and Lt Colonel Edward A. Martell, Director, Program 2. Many people have nade contributions to the work described herein; John Kinch and Fletcher Gabbard developed the counting techniques; Phyllis Gordon, David Rigotti, and Malcolm Gerdon supervised the large amount of activity and particle size work; Robert Tompkins has contributed some of the Project 2.6b datas Capt William Home, Carl Crisco, Robert Andersen, Arnold Berman, Mrs. Frances Beals, Mrs. Ann Lieder and Miss Carmen Paul have all contributed a great deal of tim and energy to the preparation of this report. Most of the data in Appendix C was furnished by the Task Group Tel Radiological Safety Unit, and is used with the permission of Major John Servis, Commander, Task Unit 7.