Comparison of the structure factors of a simple fluid measured with time-of-flight and two-axis diffractometers

In two recent experiments the static center-of-mass structure factor of liquid deuterium has been measured using both time-of-flight neutron diffraction at a pulsed source and two-axis diffraction at a reactor source. The comparison of the two experimental results shows that a discrepancy is present, which is larger than the experimental errors and appears to be due to systematic effects. Here we show that, if physical constraints are imposed on the pair correlation function g(r), most of these effects can be removed and the two sets of data are brought to agree with each other within the statistical uncertainties.