CNRS Université Bordeaux

Accueil du site > ANGLAIS > Research > ACEN: nuclear data for nuclear energy, new fuel cycle and nuclear waste transmutation > Activities > Thorium cycle > Alpha yield ratio

Alpha yield ratio

The main difficulty in the measurement of the ^{233}U \alpha yield ratio ( \alpha = σ(capture)/ σ(fission) is the separation of γ rays associated with the reaction ^{233}U(n,γ) from the ones that come from fission fragments and which represent parasitic radiation.

  • The prototype of an ionization chamber that would allow to identify fission fragments was constructed and tested on AIFIRA accelerator of CENBG. Detection efficiency for fission exceeds 90% and the time resolution of the setup is 2 ns.

    Picture of the setup: the ionization chamber is placed on the beam axis and C_{6}D_{6} detector is located at 90°.

  • The C_{6}D_{6} detector served for counting the emitted γ-rays by the method explained in the part Radiative capture ^{233}Pa(n,γ).
    The final detector set-up will contain 2 mg of ^{233}U distributed among 5 targets by 0.4 mg. These targets will be fabricated by radiochemists at IPN Orsay. The first series of measurements are scheduled on the time flight basis of GELINA accelerator of IRMM at Geel. The setup will consist of an ensemble of 10 detectors for γ rays of C_{6}D_{6} type surrounding the ionization chamber that will work in the anticoincidence in order to eliminate γ rays originating from fission fragments.