Page 25 - bukuneutron

neutron velocity n,iv=final neutron velocity n,fv=initial
target velocity T,iv=final target velocity. The energy
after scattering is similar with the energy before the
scattering as shown in Equation 1.3.This shows that
the energy is totally transferred in an elastic scatter-
ing. Elastic scattering involved neutron in the energy
ranges from 30 eV to 0.5 MeV can gives slow down
process.

Conservation of momentum (mV)

(mNVNi) + (mTVTi) = (mNVNf ) + (mTVTf ) (1.1)

Conservation of energy 1 (mN V2Ni )
2

1 (mNVN2 i ) + 1 (mTVT2 i ) = 1 (mN V2Nf ) + 1 (mTVT2 f )
2 2 2 2
(1.2)

Ei = Ef (1.3)

The energy transferred from neutron to the nucleus
of of the atom during collision is given in Equation 1.4[?].
Where A is the mass number of the nucleus.

Ef = A – 1 2 (1.4)
Ei A + 1

This equation show that the kinetic energy of neutron
after collision can lose totally for hydrogen atom there-
fore this is a main reason in the slow down process
of fast neutrons. This indicates that elastic scattering
results in the slow down process.

12