Energy of Neutrons liberated in the Nuclear Fission of Uranium induced by Thermal Neutrons

Article metrics

Abstract

IT has been shown that fast neutrons are liberated in the process of nuclear fission induced in uranium by primary thermal neutrons. Two different methods of detection have been used: in the first method1, the primary and (if any) secondary neutrons are absorbed in a medium in which an endo-energetic reaction can take place, leading to the formation of an easily detectable radioactive nucleus. If the energy threshold is situated above the maximum energy of the primary neutrons, any positive results observed must be ascribed to the secondary neutrons. In the second method2, elastic collisions of fast neutrons with heavier nuclei are observed by means of an ionization chamber filled with a gas at atmospheric pressure and connected to a linear amplifier. In order to study separately the effect due to the primary thermal neutrons, the experiment is performed with, and without, a cadmium shield between the source and the uranium mass.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1

    Dodé, M., von Halban, jun., H., Joliot, F., and Kowarski, L., C.R., 208, 995 (1939).

  2. 2

    Szilard, L., and Zinn, W., Phys. Rev., 56, 799 (1939).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

VON HALBAN, H., JOLIOT, F. & KOWARSKI, L. Energy of Neutrons liberated in the Nuclear Fission of Uranium induced by Thermal Neutrons. Nature 143, 939 (1939) doi:10.1038/143939a0

Download citation

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.