AbstractThe diffusion parameters of light water have been measured by the pulsed-source method. The neutron bursts were produced from a Texas Neutron Generator by pulsing the ion source and using the3H (d, n)4He reaction. Neutrons were injected into spherical volumes of H2O and the decay constants of the neutrons were determined by means of an enriched BF3miniature proportional counter. Neutron lifetime measurements were performed on small and large water samples with values of the geometric buckling from 0.035 to 0.655 cm−2. A harmonic analysis was conducted for the large geometries, while the waiting time method was used for the smaller ones. In the harmonic analysis, it appeared that a detector in a sphere is more sensitive to neutron fluctuation with time than it would be in a rectangular or cylindrical system. The diffusion parameters,D0andC, were determined by fitting the decay constants to the equationsand, whereandare the geometric and the corresponding transport buckling, respectively. The second fit gave a lower standard deviation of C than did the first fit.