i ’ 126474 st Ey Pee - D VERSION ONLY Bee A. C. Graves ; ‘ : CO - * mt ta tO a . + iy thee fob tates ELUNE? itt O24 } _ me MT “ April 8, a 1952 ER. ¥. Plank Hin & 46s . yl Siieléed Flying Cl.thes for Sampling Aircraft Fers.anel, Operation Ivy. Hike exot, Gperation Ivy, r 2.atd roa relative to gaum radiations vith energies — '2£ The maior source of this soft reAiation arises fron the U"S? rorzed by the capture cf a nectron Ralal by yess, rr decrease the size cof elouwl saxzples vhich ean be bollected by manned aircraft — PereatineienornatiteiceateersccnsNatntiettercatrannyoe example, it hes | C2 The effect of relatively large ascunts -f such rediation is to oven estimated that the sample size will te decreased by a factor (MM ar the Mike shit yield is MMIIcoxperes with the sanple size obtainable from a pure fission bond vith a MB y!cis. 2. Fortunately, it ts possible to attenuate greatly the intensity of sft gare -radiation with relatively little shielding material. The expected proportion of eoft radiation f:e the Mike shct requires about five half-thicknesses cf shididine to reduce the total flux within the aircraft to a level comperable with a fission beuh of the sane exercy. If one asses that the shielding pr vided by the alrcraft itself te equal to one half-thickaoss, only four half-thicknesses are required. 3. In the energy range of ecmern lead can be asaused to have an average half-thickness cf about 0.2 gu/ea®,. Rough ealeulations indicate that it should be possible to design flight elothing which wild affcrd a four or five copten/DOF LANL RE . _ CLASSIFICATION CANCELLED el DELETIONS Ye SS t earnest R orgs Z 2 24/6 co tas of2.