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“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
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