Determination of Neutron Flux Parameters after Installation of Cd-Lined for Implementations of ENAA and FNAA with NIRR-1
R.L. Njinga, Y.V. Ibrahim, M.O. Adeleye, S.A. Jonah

Abstract
A permanent Cd-lined irradiation channel has been installed in one of the large outer channel of NIRR-1 for use in epithermal and fast NAA procedures. Measurements performed with Cu-wires and (0.1)%Au-Al foils to characterize the thermal, epithermal column and check its effect on the neutron flux distributions via the specific activities obtained using (n,γ), (n,p) and (n,α) reactions in other channels (A-1, B-2, B-3, and B-4) shows that the flux distributions have not been affected by the Cd-liner in outer channel A-3. The epithermal neutron flux and fast neutron flux in the Cd-lined Channel A-3 were determined using 0.1%Au-Al foil monitor via the 197Au(n, γ)198Au and 27Al(n, p)27Mg reactions and results were 3.96E+09 ncm-2s-1 and 1E+10ncm-2s-1 respectively at an operating power of 15.5kW which correspond to a thermal neutron flux setting of 5.0E+11ncm-2s-1 on the control console. The thermal flux evaluation was 4.89E+11ncm-2s-1 in the inner channels A-1, B-2, B-3 and 2.45E+11ncm-2s-1 in the outer channel B-4. The epithermal flux in the inner channels was 2.55E+10ncm-2s-1 and 1.28E+11ncm-2s-1 in the outer B-4. The epithermal and fast neutron flux in the Cd-lined channel provides a platform for implementation of epithermal and fast NAA techniques in NIRR-1.

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