-lfins “An Experimental Approach to the Nature AOOLTT and Characteristics of Primary Fission Fragments “/ Peter C. Stevenson and Harry G. Hicks Lawrence Radiation Laboratory, University of California9 Livermore, California December..1964_ (ficeiteet a7 ToPesci Joes) ABSTRACE Positive ions of charges 1, 2, 3, and 4 were obtained for each of several masses in a beam of recoiling fission fragments from a thick U target. 235 The existence of such low-charged ions was demonstrated by resolv- ing the beam after passing it through parallel electric and magnetic fields. Energies of these low-charged ions are approximately proportional to their charges. Abundances of the low-charged ions are of the order of 1/2% of the total number of emitted fission fragments. At higher charges, the charge on | a fission fragment emitted from a thick source appears to be roughly pro- portional to its velocity. Abundances of low-charged ions appear to depend on their chemical properties. INTRODUCTION Although a great deal of precise experimental information is now avail- able concerning the distribution of mass between the two fragments of a fisSioning nucleus, the analogous problem of the distribution of nuclear charge in fission is ina much less satisfactory state. If in the "act of fission" we include the emission of the prompt neutrons, the mass of each fission product is established (except for the rare case of the delayed neutron emitters) as 9001830 |