1 - IAEA Nuclear Data Services

131 -
is made. The total and the total inelastic cross
sections are calculated from the experimental results
and are shown in figs. 2 and 3.
1.3.3. On Natural Silicon
At the end of 1966, angular distributions of neutrons
elastically and inelastically scattered by natural
silicon were measured at eight energies between 4.00
and 5.75 MeV. The final absolute neutron differential
elastic and inelastic (Q = 1.77 MeV) scattering cross
sections were evaluated. At the highest primary neutron
energy of 5.75 MeV also the cross sections for neutron
differential inelastic scattering leading to the second
(Q = 4.61 MeV) and to the third (Q = 4.97 MeV) excited
PR
states of the Si nucleus were extracted from the
measurements [6]
1.3.4. Neutron Angular Distributions from the C(d,n) ^N and
15 N(d,n) 16 0 Reactions T7]
A typical time-of-flight spectrum for the reaction
l4 C(d,n) 15 N is shown in fig. 4.
1.3.5. On Carbon
Since the total cross section of Carbon is a monotonic
function of the neutron energy below 2.0 MeV
and since only neutron elastic scattering is possible
in the same energy region, the differential neutron
scattering cross section of Carbon is especially well
suited as a standard for neutron scattering in this
region. For this reason accurate determination of
the differential elastic scattering cross sections
is necessary. So far angular distributions at eight
primary neutron energies between 0.8 and 1.5 MeV
were measured. Up to now at each energy, measurements
were taken between 20° and 150° in angle steps
of 10°.