A Geant4 procedure for precise simulation of PGNAA prompt \(\gamma\)-ray spectrum in a wide energy range up to 8 MeV

In reality, after subtracting the beam background from the prompt \(\gamma\) $\gamma$ -ray spectrum induced by the irradiated sample with the same time measurement, it still exists the remaining \(\gamma\) $\gamma$ -ray background induced by the nuclei capturing the thermal neutrons scattered by the sample. This makes it difficult to validate the accuracy of the PGNAA detector response between the simulation and the experiment in the wide energy range. In this study, a simple method to construct the remaining \(\gamma\) $\gamma$ -ray background in the simulation prompt \(\gamma\) $\gamma$ -ray spectrum of \(^{35}\) ${}^{35}$ Cl(n, \(\gamma\) $\gamma$ ) \(^{36}\) ${}^{36}$ Cl reaction is proposed. Then the simulation prompt \(\gamma\) $\gamma$ -ray spectrum with the remaining \(\gamma\) $\gamma$ -ray background is compared to the experimental spectrum to validate the simulation PGNAA detector response in the energy range from 0.1 MeV to about 9 MeV.