  Linear alkylbenzene has been recently used as the solvent of liquid
scintillator by several neutrino experiments. The energy quenching effect of a
linear alkylbenzene based liquid scintillator is studied in this paper with a
14 MeV D-T compact neutron generator, to improve the energy non-linearity
modelling of this kind of detectors. The recoiled proton in the liquid
scintillator has a kinetic energy ranging from 0.5 MeV to 13 MeV. The data is
used to extract the parameters of the Birk's law, an empirical model to
describe the energy quenching effect of the liquid scintillator.
