Efficiency measurements of deuterated liquid scintillators using d(d,n)He coincidence events

Deuterated liquid scintillators are promising from the perspective of n/γ separation and neutron energy measurement without time-of-flight. In order to turn these into precision instruments for nuclear physics, however, the absolute efficiency must be known. The efficiency is typically a function of energy and is strongly dependent on the electronics thresholds used with the photomultiplier detectors. This study involves the extraction of this efficiency using the d(d,n)³He reaction (E_d=16.0 MeV) and n-³He coincidence events. The detection and identification of the ions are very efficient and allows one to project pure monoenergetic neutron spectra all the way down to the electronics threshold. Timing information was also recorded in these measurements to provide further constraints and a consistency check.