Abstract:
The production of transuranium nuclides in pulsed neutron fluxes from thermonuclear explosions has been studied within the kinetic model of the astrophysical $r$-process taking into account the time dependence of external parameters and processes accompanying the beta decay of neutron-rich nuclei. Neutron fluxes depending on the time in the range of $\sim 10^{-6}$ s have been simulated within the developed adiabatic binary model. The probabilities of beta-delayed processes have been calculated within the microscopic theory of finite Fermi systems. The yields of transuranium nuclides $Y(A)$ have been calculated for three experimental thermonuclear explosions Mike ($Y_M$), Par ($Y_P$), and Barbel ($Y_B$) (United States). The rms deviations of the calculations from experimental data are $91$, $33$, and $29\%$ for $Y_M$, $Y_P$, and $Y_B$, respectively. These deviations are much smaller than those for other known calculations and are comparable with the proposed exponential approximation ensuring rms deviations of $56$, $86.8$, and $60.2\%$ for $Y_M$, $Y_P$, and $Y_B$, respectively. The even-odd anomaly in the observed yields of heavy nuclei is explained by the dominant effect of processes accompanying the beta decay of heavy neutron-rich isotopes.
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