
Scintillator materials emit pulses of light when exposed to ionising radiation or high-energy charged particles. Today, brighter fast scintillators are needed for advanced applications to acquire data with high signal-to-noise ratio in short time windows, such as in time-of-flight positron emission tomography (ToF-PET) imaging for cancer.
In the article “Highly Luminous Scintillating Nanocomposites Enable Ultrafast Time Coincidence Resolution for 𝜸-rays Detection with Heterostructured Multilayer Scintillators”, DOI: 10.1002/adfm.202421434, pubblicato sulla rivista Advanced Functional Materials (Wiley, Impact Factor 18.5, 2023 Journal Impact Factor, Journal Citation Reports (Clarivate Analytics, 2024)). Dr. Valeria Secchi, Dr. Irene Villa, Prof. Francesco Meinardi and Prof. Angelo Monguzzi of the department of Materials Science, University of Milano-Bicocca, developed a highly luminous composite polymeric fast scintillator loaded with high-density hafnia nanoparticles to be used as the fast emitter in the multilayer scintillators architecture. The research has been conducted in collaboration with the INFN Sezione di Milano, the European Labs of CERN in Genève and the FZU - Institute of Physics of the Czech Academy of Sciences (FZU) in Prague (CZ).
By fine-tuning the electronic properties of the system components, namely the host matrix, the heavy nanoparticles and the fluorescent dye used as the final emitter, we improve the yield of charge recombination in the host matrix and the efficiency of energy transfer from the host to the embedded chromophores, thus realising an extremely bright polymeric nanocomposite scintillator that surpasses any commercial polymeric material.
A series of 100 μm-thick nanocomposite films have been coupled to 100 μm scintillating crystalline sheets, thus realizing a multilayer scintillator of 3 × 3 ×3 mm3 size as a prototype detection pixel for ToF-PET scanners that upon interaction with 511 keV 𝛾 - rays shows an ultrafast time resolution of 115 ps. This value is half of the one of commercial machines thus opening the way to more sensitive, accurate, fast and safer application of this imaging technique.