[عاشقة النوويه]

Chapter 6
Binary Nuclear
Reactions
By far the most important type of nuclear reaction is that in which two nuclei
interact and produce one or more products. Such reactions involving two react ants
are termed binary reactions. All naturally occurring nuclides with more than a
few protons were created by binary nuclear reactions inside stars. Such nuclides
are essential for life, and the energy that nurtures it likewise derives from energy
released by binary nuclear reactions in stars.
Binary nuclear reactions are shown schematically as
A + B —>C + D + E + - - -
In all such reactions involving only the nuclear force, several quantities are conserved:
(1) total energy (rest mass energy plus kinetic and potential energies),
(2) linear momentum. (3) angular momentum (or spin). (4) charge, (5) number of
protons,1 (6) number of neutrons,1 and several other quantities (such as the parity
of the quantum mechanical wave function, which we need not consider).
Many binary nuclear reactions are caused by a nucleon or light nuclide x striking
a heavier nucleus X at rest in our frame of reference. Although several products may
result, very often only two products y (the lighter of the two) and Y are produced.
Such binary, two-product reactions are written as
x + X —> y + Y or, more compactly, as X(x, y)Y. (6-1)
In this chapter, the consequences of conservation of energy and momentum in
such two-product binary reactions are examined. The kinetic energies of the products
and their directions of travel with respect to the incident particle are of particular
interest. Such considerations are usually referred to as the kinematics of the
reaction.
1The number of protons and neutrons is not necessarily conserved in reactions involving the socalled
weak force, which is responsible for beta and electron-capture radioactive decays.
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