Influence of resonances on the $^{11}$B(n,gamma)$^{12}$B capture reaction rate. III. Capture to the 2nd, 3rd and 4th excited state of $^{12}$B

Abstract

Within the framework of the modified potential cluster model with a classification of orbital states according to Young diagrams, the possibility of data description of the radiative neutron capture on 11B to the second excited state of 12B at 1.67365 MeV (2-) and prediction absentee of experimental data for the total cross sections to the third and fourth excited state of 12B at 2.6208 MeV (1-) and 2.723 MeV (0+) for reaction energy of 10 meV (1 meV = 10-3 eV) to 7 MeV was considered. The reaction rate in the temperature range of 0.01 to 10.0 T9 is calculated on the basis of obtained cross sections, which take into account resonances up to 5 MeV. It is shown, that low-lying resonances exercise a significant influence to the capture reaction rate. The approximation of the calculation reaction rate is carried out by the simple analytic formula.