Identification of Particles of Ionizing Radiation by the Analysis of Fluorescence Pulse Form of the Thin Pen Film Scintillator

Polyethylene 2.6-naphthalate (PEN) is a promising plastic scintillator material. In this paper, a thin PEN film was used for detection, identification, and energy spectrum measurements of various ionizing radiation particles. A thin PEN film was used to separate α (5.49 MeV) and β (up to 2.2 MeV) particles coming from
²³⁸
Pu and
⁹⁰
Sr +
⁹⁰
Y sources, respectively, as well as for the neutron (up to 14 MeV) and gamma separation from the isotopic PuBe neutron source. Acquired photomultiplier pulses were analyzed by the long tail method based on the delayed fluorescence intensity dependence on the mass and charge of particles absorbed. For determination of the separation quality, the figure of merit (FOM), based on the ratio of short and long tails, was used. It was found that depending on the FOM values of neutron/gamma and α/β separation, the thin PEN film is suitable for the ionizing radiation particle separation.