Differential and angle-integrated cross sections for the ⁴⁰Ca(n, α)³⁷Ar reaction from 4.0 to 6.5 MeV

Abstract.

Differential cross sections for the ⁴⁰ Ca(n,$\alpha_{{0}}^{}$) , $(n,\alpha_{1,2})$ and $(n,\alpha_{3,4,5})$ reactions are measured at neutron energies of 4.0, 4.5, 5.0, 5.5, 6.0 and 6.5MeV using a double-section gridded ionization chamber and two CaF₂ samples. Monoenergetic neutrons were produced through the ² H(d, n)³ He reaction with a deuterium gas target. A BF₃ neutron counter was utilized to normalize the neutron flux among different measurements. The absolute value of neutron flux was calibrated using a ²³⁸U sample. Angle-integrated cross sections for the ⁴⁰ Ca(n,$\alpha_{{0}}^{}$) , $(n,\alpha_{1,2})$ and $(n,\alpha_{3,4,5})$ reactions are obtained from the integration of the differential data. Model calculations are performed using the TALYS-1.6 code and general agreement is achieved between measurements and calculations. Then the total ⁴⁰Ca(n,$\alpha$)³⁷Ar cross sections are derived from the angle-integrated cross sections combined with the code calculations. Present results are compared with existing measurements and evaluations.