Search

Radiation possesses inherent physical characteristics, such as penetrability and radionuclide energy, which enable its widespread applicability in fields such as medicine, industry, environment, security, and research. Advancements in scintillator-based radiation detection technology have led to revolutionary changes by ensuring the safe use and precise measurement of radiation. Nevertheless, certain fields require higher scintillation yields to obtain more refined and detailed results. Therefore, in this study, we explored inorganic scintillators coated with perovskite nanomaterials to detect gamma rays with high light yields. By mixing perovskite with a polymer, we improved the intrinsic characteristics of quantum dots, which otherwise failed to maintain their performance over time. On this basis, we investigated the interactions among inorganic scintillators and a mixed material (CsPbBr3 + PMMA) and confirmed an increase in the scintillation yield and measurement trends. Furthermore, optimized scintillation yield measurement experiments facilitated gamma spectroscopy, demonstrating the validity of our approach through the analysis of the peak channel increases in the energy spectra of various gamma sources in relation to the increased scintillation yield. [ABSTRACT FROM AUTHOR]

In this study, a radiation measurement system with multifunctions for the rapid radiological characterization of a decommissioned nuclear facility site was developed and evaluated. The system remotely and simultaneously measures the beta and gamma radiation from the soil at a decommissioned nuclear facility site and wirelessly transmits the measurement data to the main server, which collects and analyzes the data. The radiation-measuring part of the system is composed of a sensing probe, multichannel analyzer (MCA), and laptop computer. The sensing probe is a phoswich radiation sensor (PHORS) consisting of two inorganic scintillators (NaI(Tl) and CaF2(Eu)), each of which simultaneously measures the count rates and energies of the beta and gamma radiation. To test the performance of the PHORS, the beta and gamma radiation from a radiation source at 0–10 cm depths (at steps of 1 cm) under a soil surface was measured. The measurements show that the radiation count rates agree well with the theoretically predicted ones; the PHORS is as good as commercial radiation detectors in providing the energy spectrum of a radionuclide. In addition, a chi-square test was conducted, and the energy resolution was evaluated. The communication part of the system consisting of a global positioning system (GPS) and long-term evolution telecommunication (LTE) modem can successfully transmit the measurement data and their location information. [ABSTRACT FROM AUTHOR]

Optical fibers can be a medium to produce Cerenkov light due to their dielectric components, and radiation-induced light signals can be obtained using optical fibers without any scintillating material. In this study, we measured and characterized gamma-ray induced Cerenkov light in silica optical fibers, a plastic optical fiber, and a plastic wavelength shifting fiber in order to select the adequate optical fiber for producing Cerenkov light. Also, we measured the intensity of Cerenkov light as functions of irradiated length, irradiation angle, and thickness of various scatterers using the chosen optical fiber. [ABSTRACT FROM PUBLISHER]

We developed a scintillating fiber-optic image sensor system (SFISS) using square plastic optical fibers (POFs), a scintillating film, a right-angle mirror, and a complementary metal-oxide semiconductor (CMOS) image camera for dosimetry in radiotherapeutic applications. In this study, the scintillating light images were obtained for measuring two-dimensional planar dose distributions of a 6MV photon beam in a solid-water phantom. We also measured the percentage depth doses (PDDs) of 6 and 15MV photon beams using the SFISS and compared them with those obtained using conventional dosimetry films. The proposed sensor has many advantages, such as real-time readout, high-resolution measurement, and lack of corrections for temperature, pressure, and humidity. From the results of this study, it is expected that a SFISS can be developed to accurately measure the dose distribution in a small beam field for stereotactic radiosurgery (SRS). [ABSTRACT FROM AUTHOR]

A fiber-optic radiation sensor (FORS), which is composed of an inorganic scintillator, a plastic optical fiber (POF), a photomultiplier tube (PMT), and a multichannel analyzer (MCA), was developed for gamma-ray energy spectroscopy. In this study, we selected a cerium-doped lutetium yttrium orthosilicate (LYSO:Ce) as the sensitive element of the FORS and found that LYSO:Ce with dimensions of 3 × 3 × 15mm gives the best performance in obtaining a gammaray energy spectrum. The FORS allows us to measure the energy spectra of Co-60, Na-22, and Cs-137. [ABSTRACT FROM AUTHOR]

In this study, we developed a remote gamma-ray spectroscopy system based on a fiber-optic radiation sensor (FORS) that is composed of an inorganic scintillator coated with reduced graphene oxide (RGO) and a plastic optical fiber (POF). As a preliminary experiment, we measured the transmitted light intensities using RGO membranes of different thicknesses with different wavelengths of emitted light. To evaluate the FORS performance, we determined the optimal thickness of the RGO membrane and measured the amounts of scintillating light and gamma energy spectra using radioactive isotopes such as 60Co and 137Cs. The amounts of scintillating light from the RGO-coated inorganic scintillators increased, and the energy resolutions of the gamma-ray spectra were enhanced. In addition, the gamma-ray energy spectra were measured using different types of RGO-coated inorganic scintillators depending on the lengths of the POFs for remote gamma-ray spectroscopy. It was expected that inorganic scintillators coated with RGO in FORS can deliver improved performance, such as increments of scintillating light and energy resolution in gamma-ray spectroscopy, and they can be used to identify nuclides remotely in various nuclear facilities. [ABSTRACT FROM AUTHOR]

Radiation from gamma-ray emitting radionuclides poses significant health risks due to its high penetrating power. Currently, no technique offers effective shielding against it. Nevertheless, the rapid increase in the production and application of radionuclides warrants efficient and reliable radionuclide-detection systems. Although conventional scintillation detectors that adopt spectral analysis are widely used for their cost-effectiveness and robustness, their performance can be hindered by factors such as radioactive statistical fluctuations and background radiation. Advanced spectral-processing techniques, including machine-learning approaches, offer improvements; however, they are generally computationally intensive and not suitable for rapid onsite applications. In this study, a novel analytical approach for radionuclide identification based on the ratio of scintillation light output from scintillators with different attenuation properties is proposed. The scintillator assembly comprises four cylindrical scintillators: bismuth germanate (BGO), cerium-doped gadolinium gallium garnet (GAGG:Ce), europium-doped calcium fluoride (CaF 2 :Eu), and polyvinyltoluene-based plastic scintillators. The deposited energy in each scintillator is simulated using the Monte Carlo N-Particle Transport (MCNP) code, and the amount of scintillation light output (SLO) is calculated by a mathematical light yield model of the scintillator. From the calculated light output, the light output ratios for different scintillator combinations are derived and their dependence on the energy of incident gamma rays is evaluated. This approach exploits a parameter called equivalent energy to estimate the gamma-ray energy, which is then used to identify gamma ray-emitting radionuclides by comparing the results with known intensity-weighted average energies. The proposed method is validated with both monoenergetic and polyenergetic gamma rays using standard gamma-ray data. The results demonstrate that SLO ratio-based approach can effectively identify radionuclides without relying on traditional spectral measurement techniques, offering a promising alternative for rapid and efficient gamma-ray detection and analysis. • In MCNP simulation, we identify monoenergetic/polyenergetic gamma-ray radionuclides using scintillators. • Scintillators with various characteristics provide diverse radionuclide features. • Scintillation light output ratios allow identification in specific energy levels. • The proposed approach is simple and practical for radionuclide identification. [ABSTRACT FROM AUTHOR]

Abstract: We fabricated a novel fiber-optic Cerenkov radiation sensor using a Cerenkov radiator for measuring beta-particles. Instead of employing a scintillator, transparent liquids having various refractive indices were used as a Cerenkov radiator to serve as a sensing material. The experimental results showed that the amount of Cerenkov radiation due to the interaction with beta-particles increased as the refractive index of the Cerenkov radiator was increased as a results of a decrease of the Cerenkov threshold energy for electrons. [Copyright &y& Elsevier]

Abstract: In this study, we fabricated a one-dimensional scintillating fiber-optic dosimeter, which consists of 9 scintillating fiber-optic dosimeters, septa, and PMMA blocks for measuring surface and percentage depth doses of a therapeutic photon beam. Each dosimeter embedded in the 1-D scintillating fiber-optic dosimeter is composed of square type organic scintillators and plastic optical fibers. Also black PVC films are used as septa to minimize cross-talk between the scintillating fiber-optic dosimeters. To construct a dosimeter system, a 1-D scintillating fiber-optic dosimeter and a CMOS image sensor were combined with 20m-length plastic optical fibers. Using the dosimeter system, we measured surface and percentage depth doses of 6 and 15MV photon beams and compared the results with those of EBT films and an ionization chamber. [Copyright &y& Elsevier]

Abstract: In this study, we fabricated a scintillating fiber–optic dosimeter, which consists of an organic scintillator and a plastic optical fiber, for radiotherapy dosimetry. To select an adequate kind and length of scintillator for γ-rays generated from a Co-60 source, scintillating light from various kinds and lengths of organic scintillators is measured. Using a scintillating fiber–optic dosimeter, the γ-rays generated from a Co-60 therapy unit are measured and relative doses are obtained according to the field size of the γ-ray beam and the depth in a water phantom. Also, Cerenkov light generated by the interactions of primary or secondary electrons and the plastic optical fiber is measured with different field sizes and depths of a water phantom using a background optical fiber. [Copyright &y& Elsevier]