Development of Trans-Stilbene/PMMA Polymer Composites and Their Optical Characterization for Scintillation-Based Imaging and Detector Applications

Trans-stilbene (TSB) crystals are important for the detection of high-energy photons and neutrons through the process of scintillation. To fulfil the requirement of large area scintillator detector elements, trans-stilbene/poly(methyl methacrylate) (TSB/PMMA) composites have been developed. These plastic scintillator materials can be prepared in a relatively simpler manner as compared to the single crystals. The detailed optimization of the synthesis parameters has been reported. Using the optimal parameters, the TSB/PMMA composites having different TSB concentrations, up to a maximum of 35 wt% TSB, have been successfully fabricated. The fabricated composites were stable at room temperature, optically homogeneous, and transparent in a wide spectral range. The device relevant properties of the synthesized TSB/PMMA plastic scintillator, important for their deployment in optical imaging applications, such as the index of refraction, UV-Vis-NIR transmission, and photoluminescence (PL) properties, have been characterized as a function of TSB concentration in the polymer matrix and the behavior observed has been analyzed. Thin wafers of 0.5 mm thickness having different TSB concentrations were fabricated and used for demonstrating X-ray imaging with a resolution of 100~\mu m, using X-ray imaging beamline of Indus-2 synchrotron radiation facility. In addition, the samples of 5 mm thickness having two different concentrations were used for the detection of neutrons using thermal neutron beamline of Dhruva research reactor facility at Bhabha Atomic Research Centre (BARC), Trombay. The results demonstrate that TSB/PMMA composite is a potential plastic scintillator material for X-ray imaging and neutron scintillation applications.