Range and range straggling of heavy recoil atoms

Abstract

The range and range straggling of 96.8-kev Ra/sup 224/ recoil atoms produced by alpha decay of Th/sup 228/ have been measured in H/sub 2/, D/sub 2/, He, N/sub 2/, Ne, and Ar by a charged, parallelplate, collection technique. The range and range straggling of 725-kev Th/sup 226/ recoii atoms produced by bombardments of Ra/sup 226/ with 41.6-Mev helium ions have been measured in D/sub 2/, He, N/sub 2/, and Ar by this same technique. Experimental results seem to indicate that the range-energy relation for the stopping of heavy recoils by nuclear collisions is not linear, as is theoretically predicted by Bohr. The distribution of ranges about the mean range appears to be Gaussian. Various factors contributing errors to the measured range stragglings are discussed in detail P coil efflciencies of the heavy recoils produced in the (d,) (d,2n), (d,3n), and (d,p) reactions of Bi/sup 209/ have been measured at incident deuteron energies of 15 0 to 23.6 Mev for Bi/sup 209/ targets of 0 6 to 42.5 mu g/cm. The recoil effic encies of the different reaction products have been compared on the basis of probable nuclear-reaction mechanism by which they are produced. Mean ranges for Po/sup 208/ in Bi/sup 209/ have been calculated from the recoil efficiencies. (auth