—_ so4 PB . SAL Project 21.4 - External Meutron Flux Messurements - B. Bonner Three sets of external detectors placed on the northwest tip of Eoerira and at 1300 fest speced 150 feet apart. (Mohawk). Each set of detectors vere Another three sets of detectors were placed on the southeast tip of Rojoru et a distance of 2,500 feet fran wk). Thie set of detectors also were spaced 150 feet cpart, the detectors vere a sample of arsenic an‘ a sirconiue semple sealed in a boron 10 shield. It : was hoped that one could determine the mmber of fast neutrons by observing the (n,2n) reaction on these samples. The set cf semples placed on Rojoru vere recovered of July 8, and vere sent back to Livermore on July 10 for counting. The set of esmples on the northwest tip of Everiru could not be recovered at this tine since the estle had been broken. The set of samples on Eberiru vere re on fly 27 ant wat ek te twee 2 Ping 1 2 The flux at 1 meter from the device axis resulting fros neutrons emitted normal to the axis was calculated using an air meen free path of 190 yards for the Zr and 195 yards thearseaic. Prelininary results aret CY &