Nondestructive analysis for hydrogen in steel using neutron scattering

Previously these workers have analytically investigated the use of neutron scattering to detect the presence of hydrogen in steel. These studies showed that if a nearly monoenergetic beam of 24-keV neutrons is directed on a steel specimen the beam will largely penetrate through the specimen with little or no scattering because of the deep minimum in the neutron cross section at {approximately}24 DeV. Some multiple scattering will occur that will scatter neutrons with energies above {approximately}10 MeV. Virtually no scattering will be noted at neutron energies of 1 to 10 keV. If hydrogen is present in the sample, however, significant neutron scattering will be present in the 1- to 10-keV region with distinct peaks appearing at scattering angles of 40 deg or more. Theoretically, for a monoenergetic beam impinging on a steel specimen containing hydrogen, there are distinct relations between the energy and angle of neutrons scattered by hydrogen. Thus, the theoretical possibility exists to detect the presence of hydrogen in steel and other materials by experimentally measuring the presence of scattered neutrons at forward scattering angles. Initial experiments to verify that it is possible to nondestructively determine hydrogen concentration in steel by neutron scattering have been successfully completed. Additionalmore » experiments to further verify the applicability of the technique and to make its application in the 100- to 1-ppm range practical, are planned.« less