The total neutron cross section for natural carbon in the energy range 2 to 148 keV

Abstract. An experimental investigations of the total neutron cross section for natural carbon were done at Kyiv Research Reactor using neutron filtered beams with energies 2, 3.5, 12, 24, 55, 59, 133 and 148 keV. The intense neutron beams formed by composite neutron filters at reactor horizontal channels had the fluxes of about 10 6 -10 7 neutron/cm 2. s at the fixed neutron energies and this enabled to measure the neutron cross sections with accuracy better than 3%. Transmission method was used in these measurements. The results are presented together with the analysis of the known previous experimental data and the evaluated nuclear data from ENDF libraries

Neutron Scattering Cross Sections for Natural Carbon in the Energy Range 2-133 keV

Natural carbon is well known as reactor structure material and at the same time as one of the most important neutron scattering standards, especially at energies less than 2 MeV, where the neutron total and neutron scattering cross sections are essentially identical. The best neutron total cross section experimental data for natural carbon in the range 1-500 keV have uncertainties of 1-4%. However, the difference between these data and those based on R-matrix analysis and used in the ENDF libraries is evident, especially in the energy range 1-60 keV. Experimental data for total scattering neutron cross sections for this element in the energy range 1-200 keV are scanty. The use of the technique of neutron filtered beams developed at the Kyiv Research Reactor makes it possible to reduce the uncertainty of the experimental data and to measure the neutron scattering cross sections on natural carbon in the energy range 2-149 keV with accuracies of 3-6%. Investigations of the neutron scattering cross section on carbon were carried out using 5 filters with energies 2, 3.5, 24, 54 and 133 keV. The neutron scattering cross sections were measured using a detector system covering nearly 2{pi}. The detector consisting of {sup 3}He counters (58 units), was located just above the carbon samples. The {sup 3}He counters (CHM-37, 7 atm, diameter =18 mm, L=50 cm) are placed in five layers (12 or 11 in each layer). To determine the neutron scattering cross section on carbon the relative method of measurement was used. The isotope {sup 208}Pb was used as the standard. The normalization factor, which is a function of detector efficiency, thickness of the carbon samples, thickness of the {sup 208}Pb sample, geometry, etc., for each sample and for each filter energy has been obtained through Monte Carlo calculations by means of the MCNP4C code. The results of measurements of the neutron scattering cross sections at reactor neutron filtered beams with energies in the range 2-133 keV on carbon samples together with the known experimental data from database EXFOR/CSISRS and ENDF libraries are presented

Investigation of the scattering cross sections of neutrons on carbon nuclei at the reactor filtered beams

Natural carbon is well known as reactor structure material and at the same time as one of the most important neutron scattering standards, especially at energies less than 2 MeV, where the neutron total and neutron scattering cross sections are essentially identical. The best neutron total cross section experimental data for natural carbon in the range 1 - 500 keV has uncertainties of 1 - 4 %. However, the difference between these data and those based on R-matrix analysis and used in the ENDF libraries is evident; especially in the energy range 1 - 60 keV. Experimental data for total scattering neutron cross sections for this element in the energy range 1 - 200 keV are scanty. The use of the technique of neutron filtered beams developed at the Kyiv Research Reactor makes it possible to reduce the uncertainty of the experimental data and to measure the neutron scattering cross sections on natural carbon in the energy range 2 - 149 keV with accuracies of 3 - 6 %. Investigations of the neutron scattering cross section on carbon were carried out using 5 filters with energies 2, 3.5, 24, 54 and 133 keV. The neutron scattering cross sections were measured using a detector system covering nearly 2π. The detector consisting of 3 He counters (58 units), was located just above the carbon samples. The 3 He counters (CHM-37, 7 atm, diameter = 18 mm, L = 50 cm) are placed in five layers (12 or 11 in each layer). To determine the neutron scattering cross section on carbon the relative method of measurement was used. The isotope 208Pb was used as the standard. The normalization factor, which is a function of detector efficiency, thickness of the carbon samples, thickness of the 208Pb sample, geometry, etc., for each sample and for each filter energy has been obtained through Monte Carlo calculations by means of the MCNP4C code. The results of measurements of the neutron scattering cross sections at reactor neutron filtered beams with energies in the range 2 - 133 keV on carbon samples together with the known experimental data from database EXFOR/CSISRS and ENDF libraries are presented

Analysis of possible use of neutron filtered beam technique at the reactor for the carbon resonance parameters determination in the 150 keV energy region

Possibility of determination of carbon resonance parameter from the set of experimental averaged cross sections, obtained using modified filters, is analyzed, results of computed simulation of such filters on basis of up-to-date evaluated nuclear data file libraries are presented, comparison of calculated and experimental filter parameters is realized, as well as estimation of the necessary experimental accuracy for measurements of the averaged cross sections for resonance parameters determination is fulfilled

The total neutron cross section for natural carbon in the energy range 2 to 148 keV

An experimental investigations of the total neutron cross section for natural carbon were done at Kyiv Research Reactor using neutron filtered beams with energies 2, 3.5, 12, 24, 55, 59, 133 and 148 keV. The intense neutron beams formed by composite neutron filters at reactor horizontal channels had the fluxes of about 106-107 neutron/cm2.s at the fixed neutron energies and this enabled to measure the neutron cross sections with accuracy better than 1%. Transmission method was used in these measurements. The results are presented together with the analysis of the known previous experimental data and the evaluated nuclear data from ENDF libraries