The Study of Gamma-Rays Produced in the Inelastic Scattering of Neutrons

  • K.A. Connell

Student thesis: Doctoral ThesisDoctor of Philosophy


A gamma-ray spectrometer employing a sodium iodide scintillation
detector, has been constructed to observe the gamma-rays produced in
-14.2 MeV neutron interactions with elemental samples. The predominant
gamma-ray production mechanism is inelastic neutron scattering; the
source neutrons being produced by the 3H(d,n)4He reaction. The main
problem in the design of such a spectrometer is to overcome the large
background owing to the sensitivity of sodium iodide to neutrons. This
was overcome by using a gamma-ray detector neutron shield and a particle
time-of-flight discrimination system. The associated particle time-of-flight
method was used. The instant of production of a source neutron
is defined by detecting the associated alpha-particle, enabling the
subsequent neutron-gamma-ray time-of-flight discrimination. The different
particle flight times over the sample to detector flight path are measured
electronically and the system used is described.

Three elements for which there have been few or no previous
measurements were studied: silicon, sulphur and titanium. Gamma-ray
spectra have been observed for each element under 14.2 MeV neutron
bombardment, at several scattering com in the 0° to 90° angular
interval. The spectra enabled absolute differential gamma-ray production
cross-sections and angular distributions of the resolved gamma-ray lines
to be measured. The differential gamma-ray production cross-section,
angular distribution and integrated cross-section measurements are
compared with the published data where available.

The angular distribution measurements, of the gamma-rays
produced in neutron inelastic scattering, for each element are compared
with Hauser-Feshbach=Satchler compound nucleus model calculations.
Date of Award1972
Original languageEnglish


  • gamma-rays
  • neutrons

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