| samples be collec ted. at On CASTLE it is desired that the six primaryeltitose of leeri ~ ° true one arfinal an initial altitude of 42,000 feet g Mike » Becuas time intervals aentio true beon cannot range altitude this in root eeieeonIVY which were collected the total devris, theresul anane of representative truly be - conclusively to + te on the IVY “super” of the critical rad °se sing a desired to obtain are lees useful than otherwise. Jt is, therefore, highont Sy from as ‘special sample on each of the four high yield CASTLE shots u joer representativeness the main body of the cloud as possible and to check : cox786 be should samale altitude samples by comparison with it. This special at ta flight a require at least 55,000 feet true at about BY) hours and should in order 55,000 feet of asproximately one-half hour in the semmling area prove by this lower eltitudes cne or two cloud venetrations. Unless samples from high altitude sanjle, it comparison generally to be as representative as the of the primary would be desirable on "super shots after CASTLE to collect as many sarples as possible at altitudes of 55,000 feet or higher. As mentioned in paregraph 2c, the apparently lower rate of cloud disperasl above 50,000 feet would make such a capability serve the additional purpose of making it possible to plan to sample betueen to 6 hours after shot time with a greater probability of success when unfavorable wind conditions exist at lower altitudes. 3. Operational Requirements @. Aircreft 1. Samoling aircraft are required to provide the sixorimary samczlse in paragraph 2a, anc the epecialBemple described The aircraft for the six primary sandles should have the flight time capebilities in the vicinity of the cloud steici in paragraph 2c and corressonding altitude capability stated in paragreph 2d. in order to minimize exposure during return to base, these aircraft should use axial flow engines with turbine and cir intake located not less than ten fest ‘from crew compartment. They should have a speed performsnce of asproximately 0.8 mach end be capable of carrying high performance filter devices. These devices should be equipped with rainoroof valves and with a sample radiation measuring instrument to be read in the cockpit. Their location on the aircraft and the design of the filter element should minimize crew radiation and permit safe renoral of the intenscly radioactive materials collected and the transportation of thes: {materisis. The design of the filter element should also be integrated with re' ‘quirements bassd on laboratory handling operations. All air antering the cre compertment for heating, ventileting and pressurisstion purposes should be filtered to prsvent the entrance of radioactive cloud particles. Los Alamos Scientific Laboratory also has a generel requirement that the sampling aircraft be capable of carrying gee sampling equipment. As a result of a cooperative arrangement it is expected that details regarding this requirement will come from another agency. it retains, however, the greatest importance to this laboratory. The special samole aircraft should have the altitude anid flicht time charecteristice in the cloud vicinity stated in paragraph 2d. Its speed and encine tyye may be whatever is revuired. For a mediun speed aircreft, it is sugrested that the "shoe~box" type filter device developed by Tracerlat, In Ses for AFl2T+1 be adapted for use. If e higher speed jet-type aircraft is used (0.8 mech), it is suggested that a filter device similar to the tyne used on IVY be developed within the shape of the wing tank used on the aircraft. U pe LANL RC 5 50 6532: Py ' TOPIED Nee Dé The air e:4erans 338

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