The reaction117Sn (n,n′)117mSn as a primary interference in (n, γ) neutron activation analysis

The¹¹⁶Sn (n, γ)^117mSn reaction commonly used in reactor-neutron activation analysis (RNAA) turned out to be seriously interfered by the¹¹⁷Sn (n, n′)^117mSn reaction, as observed from irradiation in channels with largely different neutron thermalization. To estimate the magnitude of this primary interference an attempt was made to determine the relevant fission neutron averaged cross-section, yielding approximately σ_{n, n}, (¹¹⁷Sn)==0.09±0.01 barn. This value—believed to be the first measured and published—is remarkably high especially when compared to the 2200 m·s^?1 cross-section σ_o[¹¹⁶Sn(n, γ)^117mSn]=0.006 barn.