The NE213 scintillator has been widely used as a detector of fast neutrons

under environments with a high background of gamma rays. A technique using a two-gate integration method to do neutron-gamma pulse shape discrimination is reported. Fast and total signals are selected to make a two-dimensional plot. A 252Cf fission neutron source and the mono-energy neutrons produced by d+D reaction are used to investigate f5"2"

f5"5" and f8"2" NE213 organic scintillators. By selecting a suitable gate range

we get the n-g discrimination extremely well. For the 5"2" NE213 scintillator

the optimal gate range of fast signal is 30ns.