Measurement of thermal neutron radiative capture cross-sections of the ~(14)N and ~(19)F by in-beam γ-spectroscopy method with reactor neutrons

摘要

The cross-sections of the ~(14)N(n,γ) ~(15)N and ~(19)F(n,γ) ~(20)F reactions were measured by γ-spectroscopy method with the target placed at the end of a neutron guide of the WWR-M reactor (PNPI, Gatchina). The neutron spectrum was measured by the TOF method. The maximum of the spectrum is located at 0.028(2) eV and FWHM is about 0.03 eV. Cross-section of radiative neutron capture in aluminium and absolute y-intensities of the 1779 and 1633 keV γ-lines from beta decay of the ~(28)Al and ~(20)F, respectively, and the prompt 1678 and 1885keV γ-lines from the ~(14)N(n,γ) ~(15)N reaction were taken as standards. The thermal neutron radiative cross-sections of the ~(14)N and ~(19)F were measured to be 0.0795(13) and 0.00950(15)b, respectively. New value of the γ-intensity of the 1678 keV γ-line from the ~(14)N(n,γ) ~(15)N reaction has been proposed.