Determination of k₀ and Q₀ for ⁷⁴Se(n,γ) ⁷⁵Se, ¹¹³In(n,γ) ^114mIn, ¹⁸⁶W(n,γ) ¹⁸⁷W and ¹⁹¹Ir(n,γ) ¹⁹²Ir reactions

This work had the intention to contribute to the improvement in the quality of the values of k₀ and Q₀ for the reactions ⁷⁴Se(n,γ)⁷⁵Se, ¹¹³In(n, γ)^114mIn, ¹⁸⁶W(n,γ)¹⁸⁷W and ¹⁹¹Ir(n,γ)¹⁹²Ir. Measurements of the irradiated samples in the IEA-R1 reactor and the standard sources from the International Atomic Energy Agency (IAEA) were performed by high resolution gamma spectrometry with HPGe detector. In order to better investigate the efficiencies in energy intervals where there were no experimental points, the Monte Carlo Method was applied. The original contributions of this work were: the covariance analysis associated to the Least Squares Method, which was used for the adequate treatment of the uncertainties for the reactions ⁷⁴Se(n,γ)⁷⁵Se, ¹¹³In(n, γ)^114mIn, ¹⁸⁶W(n,γ)¹⁸⁷W and ¹⁹¹Ir(n,γ)¹⁹²Ir studied in this work, where all the partial uncertainties involved in the process were used; the experimental determination of the self-shielding factors for thermal (G_th) and epithermal (G_e) neutrons used in the determinations of k₀ and Q₀ for the ¹¹³In(n,γ)^114mIn reaction and the experimental determination of the self shielding factor for epithermal neutrons (G_e) used in the determinations of k₀ and Q₀ for the ¹⁸⁶W(n,γ)¹⁸⁷W reaction, which were not observed in the literature, as well as the determination of k₀ obtained for the ¹⁸⁶W(n,γ)¹⁸⁷W reaction in the energy of 625,51 keV, which does not exist in the recommended literature. The values of k₀ and Q₀ obtained for all reactions were compared to the values found in the literature. (author)