Measurements of differential and angle-integrated cross sections for the $^{10}$B($n, {alpha}$)$^{7}$Li reaction in the neutron energy range from 1.0 eV to 2.5 MeV


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Differential and angle-integrated cross sections for the $^{10}$B($n, {alpha}$)$^{7}$Li, $^{10}$B($n, {alpha}$$_{0}$)$^{7}$Li and $^{10}$B($n, {alpha}$$_{1}$)$^{7}$Li$^{*}$ reactions have been measured at CSNS Back-n white neutron source. Two enriched (90%) $^{10}$B samples 5.0 cm in diameter and ~85.0 ${mu}$g/cm$^{2}$ in thickness each with an aluminum backing were prepared, and back-to-back mounted at the sample holder. The charged particles were detected using the silicon-detector array of the Light-charged Particle Detector Array (LPDA) system. The neutron energy E$_{n}$ was determined by TOF (time-of-flight) method, and the valid ${alpha}$ events were extracted from the E$_{n}$-Amplitude two-dimensional spectrum. With 15 silicon detectors, the differential cross sections of ${alpha}$-particles were measured from 19.2{deg} to 160.8{deg}. Fitted with the Legendre polynomial series, the ($n, {alpha}$) cross sections were obtained through integration. The absolute cross sections were normalized using the standard cross sections of the $^{10}$B($n, {alpha}$)$^{7}$Li reaction in the 0.3 - 0.5 MeV neutron energy region. The measurement neutron energy range for the $^{10}$B($n, {alpha}$)$^{7}$Li reaction is 1.0 eV $le$ En < 2.5 MeV (67 energy points), and for the $^{10}$B($n, {alpha}$$_{0}$)$^{7}$Li and $^{10}$B($n, {alpha}$$_{1}$)$^{7}$Li$^{*}$ reactions is 1.0 eV $le$ En < 1.0 MeV (59 energy points). The present results have been analyzed by the resonance reaction mechanism and the level structure of the $^{11}$B compound system, and compared with existing measurements and evaluations.

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