A Study of Reactions of One and More Neutrons Photoemission from Bismuth

The process of the photoemission of one, two, three and four neutrons from the 209Bi nuclei with producing, respectively, 208Bi, 207Bi, 206Bi and 205Bi daughter radioisotopes was investigated at the end-point energies of $$E_{\gamma }^{{\max }}$$ = 30 and 40 MeV of bremsstrahlung photons at the AANL (YerPhI) linear electron accelerator. Particularly, for the relative yields of 208Bi/207Bi, 206Bi/207Bi and 205Bi/207Bi the following values were obtained: 10.8 ± 2.2, 0.060 ± 0.002 and (1.45 ± 0.53)×10–4 at $$E_{\gamma }^{{\max }}$$ = 30 MeV and 6.1 ± 0.5, 0.120 ± 0.006 and 0.0216 ± 0.0016 at $$E_{\gamma }^{{\max }}$$ = 40 MeV, respectively. It is shown that the predictions of the TALYS model, as well as the model which is contained in the GEANT4 package are in a contradiction with the experimental data. For instance, the predictions of GEANT4 at $$E_{\gamma }^{{\max }}$$  = 40 MeV for relative yields of 208Bi/207Bi and 205Bi/207Bi and the prediction of TALYS for 205Bi/207Bi about twice are smaller than the experimental values. At $$E_{\gamma }^{{\max }}$$ = 30 MeV, the predictions of both models for 205Bi/207Bi about two order of magnitude are smaller than the experimental values.