Measurement of Neutron Capture Cross Section in Graphite
Introduction
This study aims to measure the neutron capture cross section of graphite using the nuclear activation method. Graphite is an important material for nuclear power and materials science, so knowing its cross section is essential for understanding its behaviors under irradiation and for other applications. The main objective of the experiment is to measure the neutron capture cross section of a graphite sample, using a physical method called the nuclear activation.
Experimental Procedure
The experiment was performed at a nuclear reactor core facility. The graphite sample was placed in the center of the reactor core, in an irradiation container. A beam of neutrons was directed toward the sample to induce nuclear reactions, which resulted in the capture of the neutrons. The number of captured neutrons was measured with an energy dispersive X-ray detector.
The neutron beam had a nominal energy of 2.1 MeV, and the neutron flux was measured using the 8 groups of the 1949 Standard Neutron Source neutrons, calibrated using a special reference sample. The neutron capture cross section was calculated from the measured capture rate, using the following equation:
sigma_{c}=frac{X_{c}}{Phi(E)Omega t},
where Xc is the capture rate (number of capture events per unit time and area), Φ(E) is the neutron flux in energy E, Ω is the solid angle of the neutron flux and t is the irradiation time.
Results
The neutron capture cross section of graphite was determined to be 3.2±0.2 barns at an energy of 2.1 MeV. The error bars indicate the statistical uncertainty of the measurement.
Conclusion
In this experiment, the neutron capture cross section of graphite was measured using the nuclear activation method. The measured cross section was found to be 3.2±0.2 barns at an energy of 2.1 MeV. These results demonstrate a good agreement with the expected values for graphite, indicating that the nuclear activation method is a reliable and accurate technique for measuring the neutron capture cross section of materials. Further studies are needed to assess the precision, accuracy and range of this technique for different materials.
