f BLACKFOOT } eg s Profect 12.1 - Threshold Detectors - W. A. Biggers RL. Aamoit Zirconium detectors were placed along a line parallel to the axis of pet. (linc I) and also along a line parallel to the ot uu- tortal plane (line IT). A sample wes ala> placed at 300 meters slant range on a line at 45 tegrees to ilres J and IT. & The number of 14.1 Mew neutron~ externk] to the bomb which vould give the observel activati-ns is measured from line I to > and frow line II to be (Mig. 12.lel, note graph walues to be miltiplie! by 47). ye a et BEST AVAILASLE COPY 3 the re pevere? ased