bias ii | enee ee _ Blast Mtg Notes, 29 Dec 51 I. ; INTRODUCTION AND GENERAL IVY PLANNING a The meeting was held to complete the planning for the blast measurements to be made on Ivy by Sandia and Group J-10, LASL, and to arrive at firm decisions on placement of stations, numbers and types of gauges, and other details. A small portion of the afternoon's meeting was also devoted to a preliminary discussion of blast measurements for Snapper. The latest plans for Ivy were outlined to the Sandia group. The Super will be fired on Elugelab, and the predicted yield is 1 - 10 MT, with a fairly remote possibility of its going as high as 50 - 90 MT. The important point for blast considerations is that it will be effectively a surface shot, with the bottom of the bomb some 5 ft above ground level. While the per- : Ee centage probability of the higher yleld's being realized is not definitely fixed--it may be ~~ 0.1 per cent or slightly higher--it is felt that one should instrument fcr the nominal predicted yield of 5 MI, which would appear as a blast yield of 10 MY? because of ground reflections. A few gauges might perhaps be included to cover the higher yield range. A causeway will be built between Elugelab and Bogon, with some cables along it which it is hoped can be kept down to the level of the road. Krause's c recording station will be on Bogon; he will have no large structures on the shot island. Re perturbations to the blast, the shield for his experiment will be E.N.E. of the bomb; there will be steel shields for a photographic experiment S.S.E., and a Dewar which will weigh some 20 tons. The cab itself will be the usual structure, mostly I beams. If the 500-KT shot is made, it will be an air drop over either Aomon or Runit. It has not yet been decided whether it would prece@ or come after the Super shot. So far, there are effectively no requirements for measurements except alpha and yield. Others may be desirable, but this will be discussed at a later date. Facilities for timing signals presently exist at the following locations; . s . All islands from Bogallua to Bogon Aniyranii Engebi Muzin Kirinian Aomon Biijiri Rojoa Runit Eniwetok Coral Head Rigili Artificial Island (Photo tower) Parry . “y y