SESREF — ONCLABSIFIED m ~1175=AEC APPENDIX EO Lewis L. Strauss United States Atomic Energy Commission 1901 Constitution Avenue N.W. 12-30-53 17 December 1953 Vashington, D. C. TT-1741 We consider it absolutely essential to establish] in the CASTLE Tests whether there is large close-in fall-out accompanying large-scale detonations. This knowledge is essential both to the military utilization and the SUNSHINE evaluation. The IVY Raft data program, the cloud height measurements, and RAYWIND program were cancelled. These necessary data ccnsequently are rew lacking for SUNSHINE an for the evaluation of close-in radioactive fall-out of lerg detonations. By close in we mean up to several hundred nil for the CASTL= series. We propose reactivation of these p Aanls for CASTLE. Willard F. Libby ec: Dr. Jchn C. Busher, Director Division of Biology and Medicine U. S. Atomic Energy Commission Washington, D. C. UNCLASSIFIED a LANL