1 - IAEA Nuclear Data Services

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XIX. CENTRE DE PHYSIQUE NUCLEAIRE DE L'UNIVERSITE DE LOUVAIN (Belgium)
VAN DE GEAAFF DEPARTMENT
The pulsed 4 MeV Van de Oraaff has "been utilised for the study of
different reactions involving neutron detection.
1• Elastic and inelastic scattering of 15-20 Mev neutrons on C«
G. DECONNINCK and J.P. ÜEÜLDERS
The pulsed deuteron "beam is allowed to enter in a tritium gas cell:
the energy of the neutrons from the T(dn) He reaction varies between
16 and 20 TfeV when detected at 0°.
A 2 meters iron collimator mounted on a rotating frame has been
utilized for elastic scattering measurements. The sample is a cylinder
of high density graphite.
Angula,r distributions have "been measured at 4 different energies
between 30° and 145° by a technique combining time-of-flight and pulse
shape discrimination. The aim of this work is to remove discrepancies
in the 14 îfeV existing data and to extend measurement up to 20 MeV.
Large variations in the cross section suggest the existence of resonan­
ces which are analysed with a program involving optical and resonant
theories.
Inelastic scattering cross sections on the 4>43 MeV level are also
determined by these measurements. Handling of the results "is in
progress.
Efficiency of the neutrons detectors in the 9-20 MeV region.
Large liquid scintillators are utilized in the proceeding experiments.
The efficiency is measured with the known angular distribution of the
T(dn) He reaction but also by scattering of neutrons on an hydrogenous
material. The sample was a cylinder of NE 102 mounted on a photo-