On Alpha of 235U for Sub-thermal Neutron Energies

  • H. Weigmann
  • J. A. Wartena
  • C. Bürkholz
Conference paper
Part of the Research Reports in Physics book series (RESREPORTS)


An experiment to measure the capture to fission ratio α of 235U in the sub-thermal neutron energy region, is described. The experiment is based on the measurement of specific low energy capture y-rays and prompt fission γ-rays with a Ge detector. The liquid methane moderator of the Geel linac is used. as a pulsed source of sub-thermal neutrons, the neutron energy being determined by time-of-flight. The method requires that the relative yields of the measured y-rays per capture and fission event, respectively, do not vary over the energy range considered. Resultant α-values show an increase by about 9% in the subthermal region as compared to thermal energy, corresponding to a 1.2% decrease in η.


capture to fission ratio, α of 235sub-thermal neutron energy temperature coefficient of reactivity 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    A. Santamarina and H. Tellier, Proc. Intern. Conf. an Nuclear Data for Science and Technology, Mito 1988, p.47; JAERI, Tokyo 1988.Google Scholar
  2. 2.
    H. Weigmann, P. Geltenbort, B. Keck, K. Schreckenbach and J.A. Wartena, Proc. Intern. Conf. on the Physics of Reactors, Marseille 1990.Google Scholar
  3. 3.
    M. C. Moxon, J.B. Brisland and D.S. Bond, Proc. Intern. Conf. on. Nuclear Data for Science and Technology, Mito 1988, p.75; JAERI, Tokyo 1988; M.C,. Moxon, private communication.Google Scholar
  4. 4.
    R. G. Graves, R.E. Chrien, D.I. Garber, G.W. Cale and O.A. Wassan, Phys. Rev. C8 (1973) 781.Google Scholar
  5. 5.
    T. A. Khan, D. Hafmann and F. Harsch, Nucl. Phys. A205 (1973) 488.Google Scholar
  6. 6.
    W. J. Schindler and C.M. Fleck, Nucl. Phys. A206 (1973) 374.Google Scholar
  7. 7.
    L. V. East and G.R. Keepin, Proc,. Intern. Sympos. on Physics and Chemistry of Fission, Vienna 1969, p.647; IAEA, Vienna 1969.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1992

Authors and Affiliations

  • H. Weigmann
    • 1
  • J. A. Wartena
    • 1
  • C. Bürkholz
    • 1
  1. 1.Commission of the European Communities, Joint Research CentreCentral Bureau for Nuclear MeasurementsGeelBelgium

Personalised recommendations