Capture Cross-Sections for Thermal Neutrons in Thorium, Lead and Uranium 238


EXPERIMENTS on the processes arising in thorium under neutron bombardment have shown that nuclear fission is induced only by fast neutrons of energies of about 2 Mev. or more. There exists also a radiative capture process producing an isotope of thorium (Th 233) of 26 min. half-life; this process has a resonance character with a large contribution from thermal neutrons1. So far, the capture cross-section of thermal neutrons in thorium has not been measured. The following experiments were carried out in order to determine this cross-section.

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  1. 1

    Meitner, L., Hahn, O., and Strassmann, F., Z. Phys., 103, 538 (1938).

  2. 2

    Frisch, O. R., Kgl. Dansk Vid. Selskab. Math. Phys. Medd., 14, No. 5 (1936).

  3. 3

    Fleischmann, R., and Bothe, W., Ergeb. exact. Naturwiss., 16, 37 (1937).

  4. 4

    Bohr, N., Phys. Rev., 55, 418 (1939).

  5. 5

    Anderson, H. L., and Fermi, E., Phys. Rev., 55, 1106 (1939).

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MEITNER, L. Capture Cross-Sections for Thermal Neutrons in Thorium, Lead and Uranium 238. Nature 145, 422–423 (1940).

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