Measurement of Neutron Capture Resonance Integrals on Bromine Isotopes

Abstract

Neutron capture resonance integrals of the reactions ⁷⁹Br(n, γ)⁸⁰Br^m, ⁷⁹Br(n, γ)⁸⁰Br^g, ⁸¹Br(n, γ)⁸²Br^m, ⁸¹Br(n, γ)⁸²Br^g, and ⁸¹Br(n, γ)⁸²Br^m+g have been measured under 1-mm-thick cadmium covers inside the core of the RA-6 research reactor. The measured values are, respectively, (29.2 ± 3.1) b, (86.1 ± 8.9) b, (40.9 ± 2.3) b, (5.1 ± 1.1) b, and (46.8 ± 2.3) b. Resonance integrals of the reactions ⁷⁹Br(n, γ)⁸⁰Br^m and ⁸¹Br(n, γ)⁸²Br^m were also measured by a direct method using the gamma ray from the isomeric transition. The results are (30.3 ± 2.6) b and (42.7 ± 4.0) b, respectively. All measured resonance integrals are referred to the standard value (1562 ± 48) b, corresponding to the reaction ¹⁹⁷Au(n, γ)¹⁹⁸Au. Spectrum unfolding with the STAY’SL code showed the 1/E behavior of the neutron energy spectrum in the epithermal range. Good agreement was found between the results of this work and others published in the literature. Perturbations of epithermal activation due to the presence of cadmium covers are discussed and corrected in the cases where differential cross-section data are available.