Nuclear Reactions induced by the 14 MeV Neutrons

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The nuclear reactions of Al, Fe, Cu, Zn, Mo and Ag produced by the neutrons from the T³(d, n) He⁴ reaction have been investigated by means of the activation technique. The absolute numbers of activated nuclei in samples were determined by measuring the beta-rays from the samples with a 4π-proportional counter and applying the “method of extrapolation.”
By utilizing the variations of neutron energies in the laboratory system, an excitation curve of Mo⁹²(n, 2n)Mo⁹¹ reaction was obtained. For the cases of Al, Cl, Zn and Ag, only the gradients of excitation curves were also found.
The experimental cross sections were determined as follows: 87.2 mb±8% for Al²⁷(n, p)Mg²⁷, 120 mb±12% for Al²⁷(n, α)Na²⁴, 144 mb±13% for Fe⁵⁶(n, p)Mn⁵⁶, 556 mb±5% for Cu⁶³(n, 2n)Cu⁶², 119 mb±12% for Zn⁶⁴(n, 2n)Zn⁶³, 60.2 mb±12% for Zn⁶⁶(n, p)Cu⁶⁶, 132 mb±16% for Mo⁹²(n, 2n)Mo⁹¹, 458mb±11% for Ag¹⁰⁷(n, 2n)Ag¹⁰⁶, and 604 mb±11% for Ag¹⁰⁹(n, 2n)Ag¹⁰⁸. Comparing these results with the predictions by the statistical theory of Weisskopf et al. it was found that they agreed with each other within about factor 3, but in details, there were some discrepancies between them.
The relative behavior of excitation curve of the Mo⁹²(n, 2n)Mo reaction seems to be consistent with the above theory, though with respect to the absolute values, the theoretical curve lies above the experimental one by about 2.4.