Measurement of thermal neutron capture cross sections of ¹³⁹La(n,γ)¹⁴⁰La and ¹⁴⁰Ce(n,γ)¹⁴¹Ce using Am-Be neutron source

Neutron capture cross sections in thermal and epithermal energies can be measured experimentally by activation method using reactor neutron beam or D-T neutron beam. In the present experiment, an Am-Be neutron source facility is used to measure the thermal capture cross sections of ¹³⁹La and ¹⁴⁰Ce. Both the isotopes are fission products in nuclear reactors. The neutron capture of ¹³⁹La is used to measure operating power distribution by activation gamma measurements after reactor shutdown. A Cd-cut off method is used to eliminate the contribution from epithermal neutrons. The thermal cross sections were estimated with reference to ⁵⁵Mn sample