Scientists from Poland and Ukraine have developed a new type of detector capable of simultaneously identifying different kinds of radiation, a breakthrough that could improve medical treatments and radiation protection systems.
The findings, published in the scientific journal Crystals, were produced by researchers from the National Centre for Nuclear Research, Kazimierz Wielki University, the Oncology Centre in Bydgoszcz, the Institute of Scintillation Materials of the National Academy of Sciences of Ukraine and Kharkiv National University.
According to the National Centre for Nuclear Research, the use of composite scintillators in detectors could enable faster and more precise radiation measurements.
Scintillation detectors work by using scintillation, a phenomenon in which certain substances emit flashes of light when struck by charged particles. When ionising particles pass through a scintillator, ions and electrons are produced, generating photons that can be observed as light flashes.
Researchers said such detectors are particularly useful for real-time measurements but face challenges when operating in mixed radiation fields.
“In practice, detectors often operate in a mixed radiation field, where α, β and γ radiation are present simultaneously. Accurate analysis of such a field therefore requires the detector to be capable of simultaneously recording and separating different types of radiation, which remains a major challenge for a single detection material”, the Polish and Ukrainian scientists said.
To address this, scientists are developing detectors made of several scintillation layers. The structures consist of a larger base scintillation material topped with a thin layer of a different scintillator, allowing radiation particles to be distinguished by how deeply they penetrate the material.
“Low-energy α and β particles have low penetration depth, so they are mainly stopped in the first layer of the composite scintillator. Higher-energy radiation, particularly γ-rays, penetrates further, so we detect it in the deeper layers, mainly in the base scintillator, i.e. the substrate”, said Agnieszka Syntfeld-Każuch, lead author of the study and a researcher in the Radiation Detectors and Plasma Diagnostics Division at the National Centre for Nuclear Research.
The new study focused on composite scintillators built around a single crystal of GAGG:Ce, or cerium-doped gadolinium-aluminium-gallium garnet, a material known for its scintillation properties.
Researchers deposited a layer of TbAG, or terbium-aluminium garnet, onto the substrate using liquid-phase epitaxy. The layer was additionally doped with cerium and magnesium ions to alter its response to radiation. The resulting two-layer material was then connected to a photomultiplier to create a mixed radiation detector.
Tests showed the detector could distinguish between multiple radiation types in a mixed field.
“Our work has shown that the new scintillator exhibits a different response depending on the type of radiation, so it can be an effective tool for the simultaneous detection and separation of mixed radiation. Furthermore (…) our composite material is ideally suited for the simultaneous detection of three types of radiation – α, β and γ – using a scintillator with an epitaxial layer architecture”, said Abdellah Bachiri, co-author of the study and researcher at the National Centre for Nuclear Research.
Researchers said future phases of the project would focus on using multilayer scintillators to measure mixed radiation doses in medicine, including in BNCT, or Boron Neutron Capture Therapy.
Further work will also examine how to improve the materials’ luminous efficiency and evaluate their suitability for detecting different combinations of radiation at varying energy levels.
“However, the potential for using new composite scintillators in radiation protection and dosimetry is already evident”, the researchers said. (PAP)
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