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

Abstract

Abstract Differential and angle-integrated cross sections for the 10B(n, α)7Li, 10B(n, α 0) 7Li and 10B(n, α 1) 7Li* reactions have been measured at CSNS Back-n white neutron source. Two enriched (90%) 10B samples 5.0 cm in diameter and ~85.0 μg/cm2 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 En was determined by TOF (time-of-flight) method, and the valid α events were extracted from the En -Amplitude two-dimensional spectrum. With 15 silicon detectors, the differential cross sections of α-particles were measured from 19.2° to 160.8°. Fitted with the Legendre polynomial series, the (n, α) cross sections were obtained through integration. The absolute cross sections were normalized using the standard cross sections of the 10B(n, α)7Li reaction in the 0.3 – 0.5 MeV neutron energy region. The measurement neutron energy range for the 10B(n, α)7Li reaction is 1.0 eV≤En < 2.5 MeV (67 energy points), and that for the 10B(n, α 0) 7Li and 10B(n, α 1) 7Li* reactions is 1.0 eV ≤ En < 1.0 MeV (59 energy points). The present results have been analyzed by the resonance reaction mechanism and the level structure of the 11B compound system, and compared with existing measurements and evaluations.