Experimental determination of the electron screening potential energy for the d(d, n)~3He Reaction in ZrD_2 and D_2O in the ultralow energy region

摘要

This work is devoted to measuring of the values of the astrophysical S-factors and electron screening potential energy for a d(d,n)~3He reaction occurring at ultralow energies in zirconium deuteride ZrD_2 (3.5-7.0 keV) and heavy water D_2O (2.2-6.0 keV). The experiment was performed on the Hall pulsed plasma accelerator at the TPU Nuclear Physics Institute (Tomsk) with ZrD_2 and D_2O targets produced by the magnetron sputtering of zirconium in a deuterium environment and heavy water freezing-out on a copper support, respectively. A Χ analysis of the dependence of the neutron yields and astrophysical S-factors for the dd reaction on the deuteron collision energy E revealed that the upper bounds of the electron screening potential energy for interacting deuterons in ZrD_2 and D_2O and of the astrophysical S-factors at the deuteron collision energy E = 0 were U_e(ZrD_2) < 30 eV, U _e(D_2O) < 25 eV, S(0) = (57.2 ± 3.9) keV ? b (ZrD_2), S(0) = (58.6 ± 3.6) keV ? b (D_2O) at the 90% confidence level.