  This paper introduces in full detail a methodology for the measurement of
neutron yield and the necessary efficiency calibration, to be applied to the
intensity measurement of neutron bursts where individual neutrons are not
resolved in time, for any given moderated neutron proportional counter array.
The method allows efficiency calibration employing the detection neutrons
arising from an isotopic neutron source. Full statistical study of the
procedure is descripted, taking into account contributions arising from
counting statistics, piling-up statistics of real detector pulse-height spectra
and background fluctuations. The useful information is extracted from the net
waveform area of the signal arising from the electric charge accumulated inside
the detector tube. Improvement of detection limit is gained, therefore this
detection system can be used in detection of low emission neutron pulsed
sources with pulses of duration from nanoseconds to up. The application of the
methodology to detection systems to be applied for D-D fusion neutrons from
plasma focus devices is described. The present work is also of interest to the
nuclear community working on fusion by magnetic confinement and lasers, and
working on neutron production by accelerators or similar devices.
