Abstract
A large detector filled with a liquid organic scintillator containing cadmium has been used to measure the number of neutrons emitted by individual fragments in U235 fission by thermal neutrons. Using 4 π geometry the dependence of the number of neutrons emitted by fragment pairs on the mass ratio has been measured. The excitation energy used in neutron evaporation is determined on the basis of the semiempirical Weizsäcker formula. A sharp asymmetry in the distribution of excitation energy between the heavy and light fragments is noted. The data which are obtained are found to be in disagreement with the statistical theory of fission proposed by Fong.
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Additional information
The authors wish to express their gratitude to B. G. Erozolimskii, who was one of the people responsible for initiating this work; he also helped in its execution by a number of valuable comments and discussions. The authors also wish to thank A. A. Markov and A. A. Borodin for the design and construction of the multi-channel ratio analyzer and K. S. Mikhailov for advice and help in the preparation of the scintillator for the neutron detector.
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Apalin, V.F., Dobrynin, Y.P., Zakharova, V.P. et al. Number of neutrons emitted by individual fission fragments of U235 . The Soviet Journal of Atomic Energy 8, 10–16 (1961). https://doi.org/10.1007/BF01491225
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DOI: https://doi.org/10.1007/BF01491225