Nuclear Reaction 12C Research Articles

Depth distribution studies of carbon in steel surfaces by means of the nuclear reaction 12C(p, γ) 13N

A method is described for measuring the depth distribution of carbon in steel surfaces by means of the nuclear reaction 12C(p,γ) 13N. At proton energies of 0.457 MeV and 1.698 MeV the excitation function for this reaction exhibits sharp resonances which have been used to activate the carbon in thin layers beneath the surface. By means of irradiations at selected proton energies this technique facilitates the measurement of the depth distribution of the carbon content. It has been found that this method can be used to reveal carbon concentration profiles down to a depth of 20 μ with a resolution of between 0.26 and 1.7 μ for the two resonances. The detection limit obtained for carbon is 0.1% and the shape of the depth distribution is reproducible to within 15%. Homogeneous as well as inhomogeneous distributions (gradients) have been measured and results are compared with those given by two other methods. An account is given of the restrictions imposed by high currents which give rise to heating effects and radiation damage.

Contribution to the study of carbon and nitrogen determination by activation, using the nuclear reactions12C(α, n)15O and14N(d, n)15O

The carbon and nitrogen activation curves were determined for the nuclear reactions12C(α, n)15O and14N(d, n)15O, within the limits of the following maximum energies: 40 MeV for α-particles, and 21 MeV for deuterons. Inferences are made concerning the potential possibilities of these activation methods, from the sensitivity aspects, for the determination of carbon and nitrogen, with reference to the problem of the main interferences which have also been studied experimentally. The chemical separation process used to isolate15O after irradiation is described. Concrete examples of carbon and nitrogen determinations by these methods are given.

Studies of the carbon content of steel and its depth distribution by means of proton activation analysis

The carbon content and depth distribution close to the surface in steel samples at the 0.1–1% level have been studied, by means of proton activation in the energy range 1–4.5 MeV. A Van de Graaff accelerator was used, initiating the nuclear reaction 12C(p,γ) 13N which possesses two resonances at the energies of 0.46 and 1.70 MeV. The technique is of interest in connection with carbonization of iron products.