UCLA researchers have developed a nanocomposite scintillator material combining high-atomic-number (high-Z) nanoparticles embedded in a plastic (polymer) matrix, with tunable nanoparticle loading, that delivers higher light output and ultrafast emission (nanosecond-scale) while maintaining low background radiation and environmental stability, for use in radiation detection and medical imaging.
Scintillators are materials that emit light when exposed to ionizing radiation (X-rays, gamma rays), and are widely used in medical imaging (e.g. PET, CT), security screening, nuclear monitoring, and particle physics. Existing scintillator materials typically trade off among speed (emission time), light yield (how much light per unit radiation), stopping power (ability to absorb radiation efficiently), background radioactivity, and manufacturing cost. Plastic scintillators are fast and cheap but have low stopping power; heavy inorganic crystals absorb well but are often slow, expensive, fragile, or have higher natural background. There is a strong need for a material that brings many of these advantages together: high light output and speed, good stopping power, low intrinsic background, stable and manufacturable at scale.
This technology builds a nanocomposite scintillator by dispersing inorganic, high-Z nanoparticles (e.g. hafnium oxide) into a plastic (polymer) matrix. The nanoparticle loading fraction can be tuned to balance absorption efficiency and optical transparency. The composite can be made in centimeter-scale thickness. The material outputs about 50% more light compared to commercially available plastic scintillators, with ultrafast emission decay times in the nanosecond regime. It also exhibits very low natural radioactive background, making it suitable for both high-throughput detection and sensitive applications (where background counts matter). Standard manufacturing methods are used, and the material is designed for environmental stability.
Light output approximately 50% higher than commercial plastic scintillators
Ultrafast emission (nanosecond-scale), enabling fast timing applications
Low natural background radioactivity, improving signal-to-noise in sensitive detection scenarios
Tunable nanoparticle content, allowing optimization for different trade-offs (speed, stopping power, transparency)
Manufactureable to centimeter thickness using standard methods
High environmental stability (optical clarity, physical robustness)
Medical imaging modalities like PET, CT, and gamma cameras
Security screening (cargo, luggage) and industrial radiation monitoring
Neutrino detection and high-energy physics experiments
Reactor leak detection and environmental monitoring of gamma radiation
Applications requiring fast timing / high count-rate detection
Winardi I, Han Z, Yu H, Surabhi P, Pei Q. Nanocomposite Scintillators Loaded With Hafnium Oxide and Phosphorescent Host and Guest for Gamma Spectroscopy. Chem Mater. 2024 May 7;36(10):5257-5263. doi: 10.1021/acs.chemmater.4c00805. PMID: 38828188; PMCID: PMC11137814.
Yu, H.; Winardi, I.; Han, Z.; Prout, D.; Chatziioannou, A.; Pei, Q. Fast Spectroscopic Gamma Scintillation Using Hafnium Oxide Nanoparticles–Plastic Nanocomposites. Chem. Mater. 2023, 36 (1), 533-540. DOI: 10.1021/acs.chemmater.3c02631
Nanocomposite plastic scintillators, Qibing Pei et al., Proceedings of SPIE Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XXV, PC126960B (2023). DOI: 10.1117/12.2679205 SPIE Digital Library