Measurement of fast neutron induced (n,γ) reaction cross-section of 68Zn, 96Zr, 121Sb and 123Sb in the energy range of 1 to 2 MeV

Abstract

The (n,γ) reaction cross-section for the elements ⁶⁸Zn, ⁹⁶Zr, ¹²¹Sb and ¹²³Sb, present in the reactor structural/shielding materials, was measured by neutron activation technique in the neutron energy region of 1-2 MeV as very limited data is available in this energy range. Further, the neutron spectrum peaks in this energy region for the fast breeder reactors and proposed accelerator driven sub-critical systems. The natural strontium (^natSr) element was used as a neutron flux monitor by considering effective combined reaction cross-section for ⁸⁶Sr(n,γ)⁸⁷Sr^m and ⁸⁷Sr(n,n')⁸⁷Sr^m reactions. The pellets of mixture of sample and monitor were irradiated by a quasi-mono energetic fast neutron beam, generated by ⁷Li(p,n)⁷Be reaction at FOTIA, Bhabha Atomic Research Centre, Mumbai, India. The activity of activation products was measured by off-line gamma-ray spectrometry using High Purity Germanium Detector (HPGe). The present data with improved uncertainty and covariance analysis enhance the cross-section data base for better constraining the evaluated data and theoretical models. The theoretical (n,γ) reaction cross-sections were calculated using TALYS 1.96, which could reasonably explain the present data with the Fermi gas level density prescription.

Keywords: Fast neutron capture cross-section; Flux monitor; Neutron flux mapping; Neutron induced reaction.