Multi-Element INAA Based on ²⁵²Cf: Optimization of the Method and Comparison with INAA at the IREN FLNP JINR Facility

The article compares the results of instrumental neutron activation analysis (INAA) obtained with the ²⁵²Cf based INAA facility using at the Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences (ICh FEB RAS) and data from the IREN facility at the Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research (FLNP JINR). INAA results are affected not only by the ratio of thermal to resonance neutron fluxes in the sample irradiation zone but also by the nuclear-physical characteristics of the analyzed elements. The results demonstrate that the previously used approach for correcting neutron flux inhomogeneity using La-containing monitors is inadequate. Application of this normalization procedure leads to an underestimation of INAA results for several elements, which is confirmed by interlaboratory comparisons. The greatest discrepancies between INAA data from ICh FEB RAS and FLNP JINR are observed for elements with a thermal neutron capture cross-section to resonance integral ratio greater than 10 (e.g., As, Sm, Au). The use of element-specific normalization coefficients significantly improved result accuracy. Comparison of the corrected INAA data obtained at the ICh FEB RAS on ore certified reference materials (CRMs) with the results obtained at the IREN facility confirms the validity of this approach and highlights its potential for reliable analysis of complex mineral raw materials in the Far Eastern region of Russia.