  Plastic organic scintillators have been tailored in composition to achieve
ultra-fast temporal response, thereby enabling the design and development of
fast neutron detection systems with high timing resolution. Eljen Technology's
plastic organic scintillators -- EJ-230, EJ-232, and EJ-232Q -- are prospective
candidates for use in emerging neutron imaging systems, where fast timing is
paramount. To support the neutron response characterization of these materials,
the relative proton light yields of EJ-230, EJ-232, and EJ-232Q were measured
at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. Using a
broad-spectrum neutron source and a double time-of-flight technique, the proton
light yield relations were obtained over a proton recoil energy range of
approximately 300 keV to 4 MeV. The EJ-230, EJ-232, and EJ-232Q scintillators
exhibited similar proton light yield relations to each other as well as to
other plastic scintillators with the same polymer base material. A comparison
of the relative proton light yield of different sized cylindrical EJ-232 and
EJ-232Q scintillators also revealed consistent results. This work provides key
input data for the realistic computational modeling of neutron detection
technologies employing these materials, thereby supporting new capabilities in
near-field radionuclide detection for national security applications.
