  This paper, presents a simple method for accurate calibration of organic
scintillation detectors. The method is based on the fact that differentiating
the response function leads to accurate estimation of the Compton edge. The
differentiation method in addition to the location of the Compton edge, gives
insights into the parameters of the folded Gaussian function which is useful
for determination of the energy resolution. Moreover, it is observed that the
uncorrelated noise in the measurement of the response function does not impose
significant uncertainties in the evaluations. By simulation of the bounded
electrons and considering the Doppler effects, we are able to calculate a first
estimation for the intrinsic Doppler resolution of a plastic scintillator,
benefiting from the capability of the differentiation method.
