Abstract

Purpose. To determine the (γ, γ′)^m reaction cross section dependence on the gamma-quanta energy for the ¹³⁷Ba nucleus.
Methods. Activation analysis used for the measurement of the reaction output channels.
Results. This paper presents measurement results for the experimental determination of the ¹³⁷Ba(γ, γ′)^137mBa reaction cross section in the region E_γmax = 5-18 MeV for the maximum energies of the bremsstrahlung gamma-spectra. The work was performed on a beam of M-30 microtron electron accelerator Bremsstrahlung gamma rays. The energy dispersion of the accelerated electrons was ±(5-20) keV. The induction of the magnetic field of the accelerator and the corresponding energy of the accelerated electrons were determined by the method of nuclear magnetic resonance, and the measurement error did not exceed ±0.1%. The experimental yield curve of the reaction ¹³⁷Ba(γ, γ′)^137mBa was measured in 0.5 MeV increments and was used to calculate the cross section σ_m(E) of the reaction (γ, γ′)^m. Calculations of σ_m(E) were performed by the Penfold-Leiss method. The obtained experimental results were compared with theoretical calculations performed using the TALYS–1.9 software.
Conclusion. In the obtained cross-sections a peak can be observed with a maximum of 0.8 mb at 7.0 MeV, and a smaller peak with a maximum at 15 MeV. The observation, that the theoretical cross section closely follows the experimental data points to the domination of the statistical mechanism in the (γ, γ′)^m reaction

Keywords: nuclear reaction, isomeric yield ratio, giant dipole resonance, Bremsstrahlung gamma-spectrum

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