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This work presents the results on creation of novel types of composite scintillators based on Ce3+ doped Gd3Al5-xGaxO12 single crystalline films grown by the LPE method using PbO–B2O3 flux onto substrate-scintillators prepared from commercial Gd3Al2.3Ga2.7O12:Ce and Gd3Al2Ga3O12:Ce single crystals. The sets of films with different Ga contents x = 1.75–2.25 and various thicknesses in the 13–150 μm range were grown onto the mentioned substrates. The scintillation properties of the respective epitaxial structures (pulse height spectra, light yield and scintillation decay kinetics) were investigated under excitation by α– (239Pu) particles, β- (90Sr+90Y) particles and γ–quanta (137Cs). The best scintillation properties for simultaneous registration of the mentioned particles and quanta in the mixed radiation fluxes are demonstrated with Gd3Al2.75Ga2.25O12 film/Gd3Al2Ga3O12:Ce substrate epitaxial structure.

After the discovery of a cross-luminescence (CL) in BaF2 in 1982, a large number of CL scintillators were investigated. However, no CL scintillator superior to BaF2 has been discovered, and the research of CL scintillators has subsided. Recent technological development in medical imaging and high-energy physics created a new demand for ultra-fast scintillators further supported by the development of UV-sensitive semiconductor photodetectors. As a consequence, renewed interest in CL scintillators appeared. To satisfy the requirements of fast timing applications high photo-detection efficiency, e. i. a good spectral match between the scintillator and photodetector must be achieved. Cesium-based ternary chlorides could provide a red-shift (∼1.5 eV) of CL towards the sensitive region of the photodetector (PMT or SiPM) while keeping light output and timing characteristics comparable to BaF2.

Fast emitting polymeric scintillators are requested in advanced applications where high speed detectors with a large signal-to-noise ratio are needed. However, their low density implies a weak stopping power of high energy radiation and thus a limited light output and sensitivity. To enhance their performance, polymeric scintillators can be loaded with dense nanoparticles (NPs). We investigate the properties of a series of polymeric scintillators by means of photoluminescence and scintillation spectroscopy, comparing standard scintillators with a composite system loaded with dense hafnium dioxide (HfO 2 ) NPs. The nanocomposite shows a scintillation yield enhancement of +100% with an unchanged time response. We provide for the first time an interpretation of this effect, pointing out the local effect of NPs in the generation of emissive states upon interaction with ionizing radiation. The obtained results indicate that coupling fast conjugated emitters with optically inert dense NPs could lead to surpassing the actual limits of pure polymeric scintillators.

The sensitization of scintillation was investigated in crosslinked polymeric composite materials loaded with luminescent gold clusters aggregates acting as sensitizers, and with organic dye rhodamine 6G as the emitting species. The evolution in time of the excited states population in the systems is described by a set of coupled rate equations, in which steady state solution allowed obtainment of an expression of the sensitization efficacy as a function of the characteristic parameters of the employed luminescent systems. The results obtained indicate that the realization of sensitizer/emitter scintillating complexes is the strategy that must be pursued to maximize the sensitization effect in composite materials.