Development and implementation of Høgdahl convention and Westcott formalism for k₀-INAA application at Malaysian Nuclear Agency reactor

Abstract

The present work shows the development of k₀-instrumental neutron activation analysis (k₀-INAA) method at the Malaysian Nuclear Agency research reactor. To use the k₀-INAA method, two formalisms were regulated according to 1/ν and non-1/ν (n, γ) reaction nuclides. The reactor neutron spectrum parameters, the thermal to epithermal neutron flux ratio (f), the epithermal neutron flux shape factor (α) were measured using the bare bi-isotopic monitor and bare triple monitor methods, respectively, based on the Høgdahl convention. In addition, the modified spectral index $r(\alpha )\sqrt {T_{n} /T_{0} }$, the Westcott $g_{Lu} (T_{n} )$ factor and the absolute neutron temperature T _n parameters were determined using the Westcott formalism. ¹⁷⁶Lu was used as non- 1/ν monitor while ¹⁹⁷Au, ⁹⁶Zr and ⁹⁴Zr were used as 1/ν monitors. The average values of $r(\alpha )\sqrt {T_{n} /T_{0} } ,\,g_{Lu} (T_{n} )$ and T _n were determined to be 0.1795 ± 0.0044, 1.9729 ± 0.0234 and 50.12 ± 3.21°C, respectively. The accuracy of the method was evaluated by analysing IAEA-Soil 7, IAEA-SL 1, NBS SRM 1633A-1 and IAEA-Soil 375 as reference materials. The results show an acceptable level of consistency.