Question

Look up the cross-section data for B-10 and list any notable data related to neutron absorption versus elastic and inelastic scattering. On basis of the crosssection data, discuss why this isotope can be used for controlling the neutron population in a reactor.

Absorption Cross section at 0.0253 ev is 3840 barns.

Answer 1

Elastic & Inelastic Cross sections**

Boron	Elastic x-section (barns)	Inelastic x-section (barns)
B-10	0.144	3
B-11	5.56	0.21

**Reference: https://ncnr.nist.gov/resources/n-lengths/elements/b.html

1. The elastic cross section corresponds to the scattering of neutrons without any transfer of energy. i.e, energy of scattered neutrons remains same as that of incident energy of neutrons.

2. The inelastic cross section corresponds to the scattering of neutrons with transfer of energy from the neutrons to the scatterers.

3. So, for controlling the neutrons, it is necessary to slow them down, which is possible if the inelastic cross section of the surrounding material is high.

4. This is evident from the data that the inelastic cross section of B-10 is high as compared to B-11. So, this isotope can be used for controlling the neutron population in the reactor.