Plastic scintillators based on thermoplastics, such as polystyrene and poly(vinyl toluene) (PVT), are capable of neutron and γ radiation detection via pulse shape discrimination (PSD) when overdoped with select fluorescent molecules. This class of plastic scintillator has been extensively studied but is limited to applications suitable for thermoplastics. For applications requiring flexibility, scintillators composed of elastomers, such as polysiloxanes, offer an alternative to PVT scintillators. Polysiloxane scintillators are inherently flexible and have a short processing time on the order of 3 h in air and equivalent or better detection capability at reduced doping concentration (<5 wt %). This work presents polysiloxane-based scintillators, containing only 1–5 wt % of 2,5 diphenyl-oxazole (PPO) or 9,9-dimethyl-2-phenyl-9H-fluorene (PhF) as primary dopants and 9,9-dimethyl-2,7-distyryl-9H-fluorene (SFS) as a wavelength shifter. A 5 wt % PPO polysiloxane sample had improved neutron and gamma ray PSD and comparable light yield than EJ-299-33 tested under the same conditions, i.e., figure of merit (FoM) of 1.33 ± 0.03 at 450 keV_ee and light yield of 94% relative to EJ-299-33. The 5 wt % PhF-polysiloxane sample had a higher light yield, 144% of EJ-299-33 but lower FoM under the same conditions (FoM of 1.09 ± 0.03). This work highlights the potential of polysiloxanes as a matrix for PSD capable plastic scintillators.

中文翻译：

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高效中子和伽马射线脉冲形状识别的聚硅氧烷闪烁体

基于塑料的闪烁体，例如聚苯乙烯和聚（乙烯基甲苯）（PVT），在选择的荧光分子中过量掺杂时，能够通过脉冲形状识别（PSD）进行中子和γ射线探测。这类塑料闪烁体已得到广泛研究，但仅限于适用于热塑性塑料的应用。对于需要灵活性的应用，由弹性体（例如聚硅氧烷）组成的闪烁器可替代PVT闪烁器。聚硅氧烷闪烁体具有固有的柔韧性，并且在空气中的处理时间短于3小时，在降低的掺杂浓度（<5 wt％）下具有同等或更好的检测能力。这项工作提出了一种基于聚硅氧烷的闪烁体，该闪烁体仅含有1-5 wt％的2,5二苯基-恶唑（PPO）或9，9-二甲基-2-苯基-9H-芴（PhF）作为主要掺杂剂，9,9-二甲基-2,7-二苯乙烯基9H-芴（SFS）作为波长移位剂。与在相同条件下测试的EJ-299-33相比，5 wt％的PPO聚硅氧烷样品具有改善的中子和伽马射线PSD以及可比的光产率，即在450 keV下的品质因数（FoM）为1.33±0.03_ee和相对于EJ-299-33的光产率为94％。在相同条件下（FoM为1.09±0.03），5 wt％的PhF-聚硅氧烷样品具有较高的光收率，144％的EJ-299-33，但FoM较低。这项工作强调了聚硅氧烷作为具有PSD功能的塑料闪烁体基质的潜力。