In this work,differential cross sections ofγ-ray emission produced in nuclear reactions induced by 14.1 MeV neutrons are measured for the 4.439 MeV line from carbon,as well as for 10 individualγ-ray lines from alumi...In this work,differential cross sections ofγ-ray emission produced in nuclear reactions induced by 14.1 MeV neutrons are measured for the 4.439 MeV line from carbon,as well as for 10 individualγ-ray lines from aluminum,6 from silicon,8 from calcium,16 from titanium,6 from chromium,and 14 from iron.The measurements were conducted using the tagged neutron method with four LaBr_(3)(Ce)scintillation detectors positioned at angles of 25°,45°,60°,and 70°relative to the generator target–sample center axis.A neutron generator that can produce 16 separate beams of tagged neutrons was employed,which combined with the detector system,enabled the determination of differential cross-sections for 64 distinct angle values in the range of 17°to 89°.To simplify data visualization,the angular distributions were divided into 5°intervals,with weighted mean values of the angle and differential cross-section calculated for each interval.Corrections for multiple neutron scattering and attenuation,γ-ray attenuation,and total detection efficiency computed using GEANT4 were accounted for in the cross-section calculations.Additional measurements were performed to validate the correction calculations.The totalγ-ray emission cross-sections were obtained by approximating the angular distributions with even-order Legendre polynomial expansions up to the 6th degree,followed by integration over the full solid angle.The total systematic error for the obtained data was estimated as 9.1%.展开更多
The four-body Coulomb–Born distorted wave approximation is applied to investigate the integral as well as projectile angular-differential cross sections for single-electron capture in the collision of energetic singl...The four-body Coulomb–Born distorted wave approximation is applied to investigate the integral as well as projectile angular-differential cross sections for single-electron capture in the collision of energetic singly positive charged helium ions with helium atoms in their ground states. The formalism satisfies the correct boundary conditions. The influence of the dynamic electron correlations on the cross sections is studied by considering the inter electronic interactions in the complete perturbation potentials in post form. Also, the sensitivity of the cross sections to the static electronic correlations is studied by using the single-zeta and the highly correlated Byron–Joachain wave functions to describe the initial bound state of the active electrons. The obtained results for the energy range of 40–5000 ke V/amu are reported and compared with other three- and four-body theoretical data and available experimental measurements. The comparison leads us to discuss the validity of the applied approach and survey the interaction effects on the cross sections by recognizing the electron–electron interaction. Particularly, for differential cross sections, the comparison of the present four-body method with the experiment shows that the agreement is not as good as that for its three-body version.展开更多
文摘In this work,differential cross sections ofγ-ray emission produced in nuclear reactions induced by 14.1 MeV neutrons are measured for the 4.439 MeV line from carbon,as well as for 10 individualγ-ray lines from aluminum,6 from silicon,8 from calcium,16 from titanium,6 from chromium,and 14 from iron.The measurements were conducted using the tagged neutron method with four LaBr_(3)(Ce)scintillation detectors positioned at angles of 25°,45°,60°,and 70°relative to the generator target–sample center axis.A neutron generator that can produce 16 separate beams of tagged neutrons was employed,which combined with the detector system,enabled the determination of differential cross-sections for 64 distinct angle values in the range of 17°to 89°.To simplify data visualization,the angular distributions were divided into 5°intervals,with weighted mean values of the angle and differential cross-section calculated for each interval.Corrections for multiple neutron scattering and attenuation,γ-ray attenuation,and total detection efficiency computed using GEANT4 were accounted for in the cross-section calculations.Additional measurements were performed to validate the correction calculations.The totalγ-ray emission cross-sections were obtained by approximating the angular distributions with even-order Legendre polynomial expansions up to the 6th degree,followed by integration over the full solid angle.The total systematic error for the obtained data was estimated as 9.1%.
文摘The four-body Coulomb–Born distorted wave approximation is applied to investigate the integral as well as projectile angular-differential cross sections for single-electron capture in the collision of energetic singly positive charged helium ions with helium atoms in their ground states. The formalism satisfies the correct boundary conditions. The influence of the dynamic electron correlations on the cross sections is studied by considering the inter electronic interactions in the complete perturbation potentials in post form. Also, the sensitivity of the cross sections to the static electronic correlations is studied by using the single-zeta and the highly correlated Byron–Joachain wave functions to describe the initial bound state of the active electrons. The obtained results for the energy range of 40–5000 ke V/amu are reported and compared with other three- and four-body theoretical data and available experimental measurements. The comparison leads us to discuss the validity of the applied approach and survey the interaction effects on the cross sections by recognizing the electron–electron interaction. Particularly, for differential cross sections, the comparison of the present four-body method with the experiment shows that the agreement is not as good as that for its three-body version.
