Observation of d(t,n)α neutrons following d(d,p)t reactions in a deuterium gas cell

In order to benchmark methods used to calculate reaction-in-flight fusion reactions in ICF, and address issues related to the first claimed observation of d(t,n)α reactions in 1938, secondary d(t,n)α reactions have been observed following d(d,p)t reaction in deuterium gas. A pulsed ~100 nA 2.2-MeV deuterium beam from the TUNL FN Tandem was injected into a cylindrical multi-atmosphere deuterium gas target. The incident beam ran along the target cylinder’s 3-cm symmetry axis after its passage through a Havar entrance foil. Two different Havar foil thicknesses were used to obtain 1.5-MeV and 0.5-MeV deuteron beams entering the deuterium cell. The cylinder’s radius was 2 cm to allow for d(d,p)t tritons emitted perpendicular to the beam to range out in the deuterium gas. The neutron emission from the cell was observed via its time-of-flight to a liquid-scintillator placed at various angles to the beam direction, at a distance of ~ 2 m. Pulse-shape discrimination techniques were used to separate neutron and gamma-ray signals seen in the liquid scintillator. The observed probability for inducing d(t,n)α fusions in the cell per d(d,p)t reaction will be compared to theory.