The total thickness of lead on top of the collinctor was probably less than 1", The lines of sicht through the blast plate were protected by 1;" I.D, pipe about &" long welded to the front of the plate. these pipes lead wool was packed to a thickness of about 4", top, dround The front, and sides of the collimator were protected by several layers of sand bags. The 2300 yd station contained three phonex ecsmeras having polyethylene radiators 0.001", 0.0025", and 0.003" thick. Ilford nuclear emul~ sion plates were used at the rear sz.all anzle positions only. The four plates in each canera were as follows: 300MC2, 200C2, 30021, and 200AEl, Tn cameras at the 600 yd. station were similar except for one? anstead of a 0,003" polyethylene radiator et the front of the camera, a deateroparaffin radiator was used ct the rear. This camera was used by Louis fosen to look for the anzular distribution of protons from the rhotedisintesr-=tion of the deuteron, Ceneras were recovered from the 600 vd. station about mid-afternoon of Exday. Develonuent of the plates from Zosen's camera and from the 0,0025" radiator camera was started immediately. The C2 emulsions gave good readable plates reasonably free of background. The 21 emulsions, althoush showing less backsround, do not show at all well the beginnings of proton tracks whose energies are greater than about 10 or 12 mev. Two hundred and eighty-one tracks were measured on one of the C2 plates by Louis Rosen. The results of this analysis are shown in Table 122~1 and the neutron energy spectrum extrapolated back to the outside of the bomb is shown in Fig. 12.2-l. The cameras from the 300 yd. station were recovered three days COPY NL Re _ _ ao U! - 47 aaa i

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