A new, high-performance neutron time correlation, or coincidence, counter has been developed for the measurement of nuclear materials. This detector is an improvement over the high-level neutron coincidence counter that was used previously in that it has better counting rate capability, electronic stability, noise resistance, uniform counting zone, and portability. The system uses 3He gas tubes coupled to the shift register coincidence electronics through a new hybrid charge-sensitive preamplifier/discriminator. Counting rates of 1.3 MHz have been obtained and a counting stability of 0.002% has been measured. The system has been applied to the assay of plutonium content in metal, PuO2, and PuF4, as well as in uranium-plutonium mixtures.