Commercial Scintillator Research Articles

High‐Resolution X‐Ray Imaging With 0D Organic–Metal Halide Scintillator Featuring Reversed Exciton Trapping

AbstractScintillators, essential for applications in nuclear medicine, radiation detection, and industrial inspection, convert high‐energy radiation into visible light. Manganese (Mn)‐based inorganic–organic hybrid materials are distinguished by their thermal stability, mechanical strength, and flexibility. However, the effects of temperature on Mn(II)‐based hybrid scintillators have not been clearly analyzed, making the elucidation of their temperature‐dependent luminescence mechanisms particularly important. A notable advancement is the synthesis of Mn‐1 nanocrystals (NCs) using methyltriphenylphosphonium chloride (mtppCl) and MnCl₂. These NCs exhibit distinctive temperature‐dependent photoluminescence luminescence: the intensity decreases from 77 to 150 K but paradoxically increases at higher temperatures due to anomalous thermal exciton behavior in the [MnCl₄]2⁻ tetrahedra. Besides, Mn‐1 NCs achieve a detection limit of 1.01 µGyair/s, surpassing medical diagnostic standards and outperforming commercial scintillators such as Bi₄Ge₃O₁₂ (BGO). Additionally, they show exceptional stability under continuous irradiation and can be incorporated into a flexible scintillating film with a resolution of 11.3 lp/mm at an MTF of 0.2. The current study has further refined the luminescence mechanism of Mn(II)‐based materials and optimizes their properties for a wider range of applications.

Rod‐Like Microcrystal Scintillators Based on Organic–Inorganic Hybrid Copper Halides for X‐Ray Imaging

AbstractCopper‐based organic–inorganic hybrid halides (OIHHs) have garnered significant interest in X‐ray imaging due to their flexible structural adjustability, efficient light emission, strong X‐ray absorption, etc. Herein, four copper‐based OIHH crystals composed of the same organic ligands (isopropyl triphenylphosphonium cations, IPP+) and inorganic parts (Cu2I42−) are synthesized by varying the ratios of raw materials and types of reaction solvents. Although these crystals share identical structures, they exhibit different luminescent behaviors (blue, green, white, and yellow) attributed to vacancy defects originating from CuI. Notably, the novel copper‐based OIHH (CP2) with green emission shows the best luminescence efficiency (99.54%) and excellent scintillation performance (50675 photons MeV−1). The traditional technology of scintillation screens mixing scintillator powders and polymers often results in light scattering due to powder aggregation and inhomogeneity. To address this challenge, the dispersant polyvinyl pyrrolidone is introduced to prepare uniform rod‐like microcrystals of CP2. The scintillation screen based on CP2 microcrystals achieves a high spatial resolution of 16–18 lp mm−1, surpassing the resolution of most copper‐based OIHH scintillators. Furthermore, it is imaging capabilities are validated using a commercial X‐ray flat panel detector, demonstrating imaging performance comparable to that of commercial scintillators.

Controlled Synthesis of Terbium-Doped Colloidal Gd2O2S Nanoplatelets Enables High-Performance X-ray Scintillators.

Terbium-doped gadolinium oxysulfide (Gd2O2S:Tb3+), commonly referred to as Gadox, is a widely used scintillator material due to its exceptional X-ray attenuation efficiency and high light yield. However, Gadox-based scintillators suffer from low X-ray spatial resolution due to their large particle size, which causes significant light scattering. To address this limitation, we report the synthesis of terbium-doped colloidal Gadox nanoplatelets (NPLs) with near-unity photoluminescence quantum yield (PLQY) and high radioluminescence light yield (LY). In particular, our investigation reveals a strong correlation between PLQY, LY, particle size, and Tb3+concentration. Our synthetic approach allows precise control over the lateral size and thickness of the Gadox NPLs, resulting in a LY of 50,000 photons/MeV. Flexible scintillating screens fabricated with the solution-processable Gadox NPLs exhibited a 20 lp/mm X-ray spatial resolution, surpassing commercial Gadox scintillators. These high-performance and flexible Gadox NPL-based scintillators enable enhanced X-ray imaging capabilities in medicine and security. Our work provides a framework for designing nanomaterial scintillators with superior spatial resolution and efficiency through precise control of dimensions and dopant concentration.

One-Dimensional Copper-Doped Rb2AgI3 with Efficient Sky-Blue Emission as a High-Performance X-ray Scintillator.

Scintillators have garnered heightened attention for their diverse applications in medical imaging and security inspection. Nonetheless, commercial scintillators encounter challenges with costly rare-earth metals and toxic elements like thallium (Tl), driving the need for sustainable, cost-effective, and eco-friendly alternatives to meet contemporary X-ray detection demands. This study focuses on exploring the potential of Cu+-doped Rb2AgI3 as an effective metal halide (MH) scintillator. One-dimensional (1D) Rb2AgI3 and Cu+-doped Rb2AgI3 single crystals (SCs) were synthesized by using the conventional temperature-lowering crystallization method. When excited by UV light, Cu+-doped SCs emitted a broad sky-blue light at 490 nm with a high photoluminescence (PL) quantum yield (PLQY) of 76.48%. Remarkably, under X-ray excitation, these Cu+-doped SCs demonstrated an outstanding light yield of 36,293 photons MeV-1, a relatively low detection threshold of 1.022 μGyair s-1, and a rapid scintillation decay time of 465 ns. The prepared translucent scintillation film has good uniformity and flexibility, with a high spatial resolution of 10.2 lp mm-1. These results position Cu+-doped Rb2AgI3 as a leading candidate among promising X-ray scintillators, offering superior scintillation light yield, excellent stability, and nontoxicity.

Neutron detection properties of Ti-doped LiGaO2 single crystalline scintillator

Photoluminescence (PL) and scintillation properties of undoped and Ti-doped LiGaO2 single crystals were investigated. In both PL and scintillation, the Ti-doped LiGaO2 crystals showed luminescence due to charge transfer between Ti4+–O2- while the undoped LiGaO2 crystal showed luminescence due to oxygen vacancies. Under thermal neutron irradiation, all the LiGaO2 crystals exhibited a clear thermal neutron peak, and the highest light yield was observed from the 3% Ti-doped LiGaO2 crystal. The light yield of the 3% Ti-doped LiGaO2 crystal was ten times higher than that of the undoped LiGaO2 crystal and comparable with that of a commercial neutron scintillator GS20. In addition, the Ti-doped LiGaO2 crystals showed high α/γ ratios up to about 0.7.

Scintillation properties of Eu-doped LiBr crystalline scintillators under X-, γ-ray, and neutron irradiation

Scintillators for neutron detection have been required as alternative detectors for 3He gas proportional counters, which are in short supply. Therefore, Eu-doped LiBr single crystals as new scintillators for neutron detection were synthesized by the vertical Bridgman method, and the photoluminescence and scintillation properties were evaluated. Under ultraviolet light and X-ray irradiation, the emission due to 4f65d1–4f7 (8S7/2) transitions of Eu2+ was observed at 440 nm. According to pulse height spectra under 252Cf neutron irradiation, 0.01 % Eu-doped LiBr showed the highest light yield of 4600 ph/n among the prepared samples, and the α/γ ratio of 0.01 % Eu-doped LiBr was 0.37, which was better than that of commercial GS20 scintillator.

Near‐unity broadband emissive hybrid manganese bromides as highly‐efficient radiation scintillators

AbstractZero‐dimensional (0D) hybrid manganese halides have gained wide attention for the various crystal structures, excellent optical performance and scintillation properties compared with 3D lead halide perovskite nanocrystals. In this work, a new family of 0D hybrid manganese halides of A2MnBr4 (A = BzTPP, Br‐BzTPP, and F‐BzTPP) based on discrete [MnBr4]2− tetrahedral units is reported as highly efficient lead‐free scintillators. Excited by UV or blue light, these hybrids emit bright green light originating from the d–d transition of Mn2+ with near‐unity PLQY (99.5%). Significantly, high PLQY and low self‐absorption render extraordinary radioluminescence properties with the highest light yield of 80,100 photons MeV−1, which reached the climax of present hybrid manganese halides and surpassed most commercial scintillators. The radioluminescence intensity features a linear response to X‐ray doses with a detection limit of 30 nGyair s−1, far lower than the requirement of medical diagnostic (5.5 µGyair s−1). X‐ray imaging demonstrates ultrahigh spatial resolution of 14.06 lp mm−1 and short afterglow of 0.3 ms showcasing promising application prospects in radiography. Overall, we demonstrated new hybrid manganese halides as promising scintillators for advanced applications in X‐ray imaging with multiple superiorities of nontoxicity, facile‐assembly process, high irradiation light yield, excellent resolution, and stability.

Sensitized Triplet-Triplet Annihilation in Nanostructured Polymeric Scintillators Allows for Pulse Shape Discrimination.

Scintillating materials emit light when exposed to ionizing radiation or particles and are used for the detection of nuclear threats, medical imaging, high-energy physics, and other usages. For some of these applications, it is vital to distinguish neutrons and charged particles from γ-rays. This is achievable by pulse shape discrimination (PSD), a time-gated technique, which exploits that the scintillation kinetics can depend on the nature of the incident radiation. However, it proves difficult to realize efficient PSD with plastic scintillators, which have several advantages over liquid or crystalline scintillating materials, including mechanical robustness and shapeability. It is shown here that sensitive and rapid PSD is possible with nanostructured polymer scintillators that consist of a solid polymer matrix and liquid nanodomains in which an organic dye capable of triplet-triplet annihilation (TTA) is dissolved. The liquid nature of the nanodomains renders TTA highly efficient so that delayed fluorescence can occur at low energy density. The nanostructured polymer scintillators allow discriminating α particles, neutrons, and γ-rays with a time response that is better than that of commercial scintillators. Exploiting that the liquid nanodomains can facilitate energy transfer processes otherwise difficult to realize in solid polymers, an auxiliary triplet sensitizer is incorporated. This approach further increases the scintillator's sensitivity toward α particles and neutrons and other high-energy processes where localized interactions are involved.

Toward "super-scintillation" with nanomaterials and nanophotonics.

Following the discovery of X-rays, scintillators are commonly used as high-energy radiation sensors in diagnostic medical imaging, high-energy physics, astrophysics, environmental radiation monitoring, and security inspections. Conventional scintillators face intrinsic limitations including a low extraction efficiency of scintillated light and a low emission rate, leading to efficiencies that are less than 10 % for commercial scintillators. Overcoming these limitations will require new materials including scintillating nanomaterials ("nanoscintillators"), as well as new photonic approaches that increase the efficiency of the scintillation process, increase the emission rate of materials, and control the directivity of the scintillated light. In this perspective, we describe emerging nanoscintillating materials and three nanophotonic platforms: (i) plasmonic nanoresonators, (ii) photonic crystals, and (iii) high-Q metasurfaces that could enable high performance scintillators. We further discuss how a combination of nanoscintillators and photonic structures can yield a "super scintillator" enabling ultimate spatio-temporal resolution while enabling a significant boost in the extracted scintillation emission.

A comprehensive investigation of the performance of a commercial scintillator system for applications in electron FLASH radiotherapy.

Dosimetry in ultra-high dose rate (UHDR) beamlines is significantly challenged by limitations in real-time monitoring and accurate measurement of beam output, beam parameters, and delivered doses using conventional radiation detectors, which exhibit dependencies in ultra-high dose-rate (UHDR) and high dose-per-pulse (DPP) beamline conditions. In this study, we characterized the response of the Exradin W2 plastic scintillator (Standard Imaging, Inc.), a water-equivalent detector that provides measurements with a time resolution of 100Hz, to determine its feasibility for use in UHDR electron beamlines. The W2 scintillator was exposed to an UHDR electron beam with different beam parameters by varying the pulse repetition frequency (PRF), pulse width (PW), and pulse amplitude settings of an electron UHDR linear accelerator system. The response of the W2 scintillator was evaluated as a function of the total integrated dose delivered, DPP, and mean and instantaneous dose rate. To account for detector radiation damage, the signal sensitivity (pC/Gy) of the W2 scintillator was measured and tracked as a function of dose history. The W2 scintillator demonstrated mean dose rate independence and linearity as a function of integrated dose and DPP for DPP ≤ 1.5Gy (R2>0.99) and PRF ≤ 90Hz. At DPP>1.5Gy, nonlinear behavior and signal saturation in the blue and green signals as a function of DPP, PRF, and integrated dose became apparent. In the absence of Cerenkov correction, the W2 scintillator exhibited PW dependence, even at DPP values<1.5Gy, with a difference of up to 31% and 54% in the measured blue and green signal for PWs ranging from 0.5 to 3.6 µs. The change in signal sensitivity of the W2 scintillator as a function of accumulated dose was approximately 4%/kGy and 0.3%/kGy for the measured blue and green signal responses, respectively, as a function of integrated dose history. The Exradin W2 scintillator can provide output measurements that are both dose rate independent and linear in response if the DPP is kept ≤1.5Gy (corresponding to a mean dose rate up to 290Gy/s in the used system), as long as proper calibration is performed to account for PW and changes in signal sensitivity as a function of accumulated dose. For DPP>1.5Gy, the W2 scintillator's response becomes nonlinear, likely due to limitations in the electrometer related to the high signal intensity.

Radiation-induced luminescence properties of AEO-SiO2 (AE = Mg, Ca, Sr, Ba) glasses doped with Sn

Optical and scintillation properties of 50AEO-50SiO2-1SnO (AE = Mg, Ca, Sr, Ba) glasses were investigated. In photoluminescence (PL) and scintillation, the glasses showed a luminescence peak around 400 nm which was attributed to the T1-S0transitions of Sn2+. The afterglow levels of theAE = Mg and Ba glasses were better than that of a commercial Tl-doped CsI scintillator. The light yields of the glasses were quantitatively acquired and theAE = Ba glass showed the highest light yield of 63 ph/5.5 MeV-α of among the glasses.

Photoluminescence and X-ray induced scintillation in Gd3+-Tb3+ co-doped fluoride-phosphate glasses, and derived glass-ceramics containing NaGdF4 nanocrystals

The glass system (50NaPO3–20BaF2–10CaF2–20GdF3)-xTbCl3 with x = 0.3, 1, 3, 5, and 10 wt % was investigated. We successfully produced transparent glass ceramic (GC) scintillators with x = 1 through a melt-quenching process followed by thermal treatment. The luminescence and crystallization characteristics of these materials were thoroughly examined using various analytical methods. The nanocrystallization of Tb3+-doped Na5Gd9F32 within the doped fluoride-phosphate glasses resulted in enhanced photoluminescence (PL) and radioluminescence (RL) of the Tb3+ ions. The GC exhibited an internal PL quantum yield of 33 % and the integrated RL intensity across the UV-visible range was 36 % of that reported for the commercial BGO powder scintillator. This research showcases that Tb-doped fluoride-phosphate GCs containing nanocrystalline Na5Gd9F32 have the potential to serve as efficient scintillators while having lower melting temperature compared to traditional silicate and germanate glasses.

Aqueous-Based Inorganic Colloidal Halide Perovskites Customizing Liquid Scintillators.

Compared to solid scintillators and organic liquid scintillators, aqueous-based liquid scintillators (AbLS) have more superiority in highly flexible scalability, yet are now limited by their low light yield (≈100 photons MeV-1 ). Here, aqueous-based inorganic colloidal halide perovskites with high photoluminescence quantum yield (PLQY) of three primary color luminescence up to 88.1% (red), 96% (green), and 81.8% (blue) are respectively synthesized, and a new generation of colloidal perovskite-mediated AbLS (PAbLS) with light yield increased in comparison with the commercial scintillator AbLS is fabricated. This paper exhibits that the excellent PLQY and colloidal dispersion of halide perovskites benefit from poly(ethylene glycol) modification and this modification ensures the vacancy inhibition and formation of defect-free surfaces in an aqueous solution. Moreover, their high luminescent emission can be maintained for 100 days at low temperatures, and such modification also promises the heat-to-cold customization of operating temperature even in ice below 0 °C. Finally, depending on the light yield of around 3058 and 8037 photons MeV-1 at room temperature and low temperature, PAbLS with shape/size scalability exhibit their robust radiation hardness (dose rate as high as 23 mGy s-1 ) and conceptual application potential in high-energy ray radiation detection from every angle of 360°.

A new promising new choice for modern medical CT scanners: Cerium-doped gadolinium yttrium gallium aluminum garnet ceramic scintillator

Cerium-doped gadolinium yttrium gallium aluminum garnet (GYGAG) ceramics show great promise as scintillators for modern medical CT scanners. They exhibit exceptional scintillation efficiency, fast decay, low afterglow, and high X-ray stopping power. However, the performance of GYGAG ceramic scintillators in modern medical CT scanners has not been thoroughly investigated, as previous research has primarily focused on optimizing material performance. To address this research gap, we prepared a high-quality GYGAG ceramic scintillator and compared its performance to that of a widely used commercial GOS ceramic scintillator in medical CT scanners. The GYGAG scintillator showed comparable afterglow intensity, but significantly higher light yields and faster scintillation decay. Additionally, we developed two-dimensional GYGAG scintillator arrays integrated into a CT detector and assessed their spatial resolution and low-contrast detectability. The successful acquisition of CT images of an adult head phantom demonstrates the promising potential of GYGAG ceramic scintillators as alternatives for modern medical CT scanner detectors.

Characterization of a water-based liquid scintillator for use in megavoltage radiotherapy beams

The measurement of the dose delivered in radiotherapy treatments is carried out using dosimeters that are often expensive to produce and sometimes toxic to humans and the environment, which leads to more complex and rigorous clinical manipulations. It is in this context that it is necessary to provide new types of scintillators that would no longer have these problems while having properties equivalent to those of human tissues. Thus, the following study presents the performance of a water-based liquid scintillator used at radiotherapy energies. The characteristics studied include the proportionality of the scintillation signal to the dose, the scintillation efficiency at two different energies as well as the identification of the Cherenkov portion of the signal for photon beams of 180 kVp, 6 MV as well as 18 MV. Spectral measurements of the scintillation solution and a solution of distilled water were acquired in order to isolate the contribution of the scintillation signal from the spectrum obtained, and then compared to a commercial scintillator, Ultima Gold. The signal exhibits a linear dose relationship with a correlation coefficient of 0.999 and lower scintillation efficiency than Ultima Gold.

Novel Monthly Quality Assurance Regimen and 5-Year Analysis Using a Proton Metrology System

PurposeTo develop a novel, monthly quality assurance (QA) regimen for a proton therapy system that uses 2 custom phantoms, each housing a commercial scintillator detector and a charge-coupled device camera. The novel metrology system assessed QA trends at a pediatric proton therapy center from 2018 to 2022. Materials and MethodsThe measurement system was designed to accommodate horizontal and vertical positioning of the commercial device and to enable gantry and couch isocentricity measurements (using a star shot procedure), proton spot profile verification, and imaging and radiation congruence tests to be performed simultaneously in the dual-phantom setup. Gantry angles and proton beam energies were varied and alternated each month, using gantry angles of 0°, 30°, 60°, 90°, 120°, 150°, and 180° and discrete beam energies of 69.4, 84.5, 100, 139.1, 180.4, 200.4, and 221.3 MeV after radiographic verification. A total of 1176 individual monthly QA measurements of gantry and couch isocentricity, spot size, and congruence were analyzed. ResultsGantry and couch star shot measurements showed beam isocentricities of 0.3 ± 0.2 mm and 0.2 ± 0.2 mm, respectively, which were within the threshold of 1.0 mm. Spot sizes for each discrete energy were within the threshold of ± 10% of the baseline values for all 3 proton rooms. The imaging and radiation coincidence test results for the 1176 individual monthly QA measurements were 0.5 mm for the 50th percentile and 1.2 mm (the clinical threshold) for the 97.6th percentile. ConclusionsIntegrating a commercial device with custom phantoms improved the quality of proton system checks compared with previous methods using radiochromic films, loose ball bearings, and foam. The scheme of alternating beam angles with discrete energies in the monthly QA-enabled, clinically meaningful verification of beam energy and gantry angle combinations while the machine performance and accuracy were being checked.

Structural, photoluminescence and scintillation properties of Ce-doped Al(PO3)3–Sr(PO3)2–CsPO3 inorganic glass scintillators for gamma- and X-ray detection

Scintillators have been commercialized as radiation detectors in several practical applications. However, fabrication of commercial inorganic crystal scintillators is time-consuming and expensive. Herein, we report inorganic glass scintillators for gamma and X-ray detection based on phosphate glasses, with alkali and alkali earth metals in the host and Ce3+ ions as emission centers. Unlike inorganic crystals, inorganic glasses have industrial advantages owing to their low cost and ease of fabrication, which facilitate the large-scale production of scintillators. Previously studied inorganic glass scintillators for gamma and X-ray detection exhibited low light yields compared to inorganic crystal scintillators. In contrast, our glass exhibits a high light yield of 3200 photons/MeV. This light yield is higher than that of previously reported glasses, whose light yields are less than several hundred photons/MeV in most cases and approximately 2000 photons/MeV as the highest value. In addition, this glass has a relatively high density of 3.33 g/cm3 and a fast scintillation decay of approximately 30 ns, which is attributed to the 5d–4f transition of Ce3+ ions acting as emission centers. These properties are suitable for gamma and X-ray detection and this glass has the potential to expand the practical applications of inorganic glass scintillators.

Gd3+-sensitized rare earth fluoride scintillators for High-resolution flexible X-ray imaging

X-ray imaging technology is widely used in the medical, industrial, and scientific fields, where highly sensitive, flexible, and cost-effective scintillation screens are crucial prerequisites. In this work, YF3:Gd3+/Tb3+ microparticles (MPs) were prepared via an ultrafast chemical precipitation method and exhibited excellent luminescent properties under the excitation of ultraviolet light and X-ray. It was found that Gd3+ doping could effectively enhance the photoluminescence (PL) and X-ray activated radioluminescence (RL) of Tb3+ owing to an efficient energy transfer process from Gd3+ to Tb3+. The prepared YF3:30%Gd3+/10%Tb3+ MPs exhibited fine environmental stability and superb X-ray RL, which was stronger than that of commercial scintillators Bi4Ge3O12 (BGO) and even comparable to that of CsI:TI single crystal. Highly flexible transparent YF3:Gd3+/Tb3+/PDMS scintillation screens were prepared to record high-resolution X-ray images of planar/nonplanar objects, where the imaging spatial resolution was 16.8 lp mm−1, which was far higher than the standard spatial resolutions required for medical computed tomography (CT) scan (2 lp mm−1) and X-ray imaging (3.5 lp mm−1). The excellent scintillation performance, superior flexibility and environmental stability of YF3:Gd3+/Tb3+/PDMS scintillation films endow them with the potential application in high-resolution industrial nondestructive inspection and biological imaging.

New ultrafast low-cost polyurethane based plastic scintillator

The study of plastic scintillators with polyurethane (PU) matrix based on cycloaliphatic isocyanate 4,4′-methylenebis (cyclohexyl isocyanate) (H12MDI) and 2,5-diphenyloxazole (PPO) as a luminescence activator is presented. A number of samples with different PPO content amounting up to 20 wt% were synthesized and their optical and luminescence characteristics were investigated. Pure H12MDI – PU based polymer exhibits low optical density in the spectral region 350–500 nm characteristic of the PPO emission band. The PU sample loaded with 5 wt% PPO demonstrated a light yield of 1088 photons/MeV and ultrafast rise and decay time of few picoseconds and few nanoseconds, respectively. The estimated coincidence time resolution (CTR) value for a PU sample is 1.4 times smaller than that known for a commercial scintillator BC-422 available for ultrafast timing applications.

Europium-bearing organic framework with excellent X-ray scintillating luminescence

Two europium-bearing organic frameworks, termed as EuTPO-1 and EuTPO-2 (H3TPO = tris(4-carboxylphenyl)-phosphineoxide), are reported in this work. A series of characterizations of EuTPO-1 and EuTPO-2, such as X-ray crystallography and photoluminescence spectroscopy, was performed to expatiate their structure and physicochemical properties. Both of them are constructed by dimers of the europium-oxygen subunit of [Eu2O16] and TPO molecule. Benefiting from high X-ray stopping attenuation and excellent luminescence efficiency, they emit sufficient luminescence when irradiated with X-rays. Meanwhile, they possess stable light outputs when exposed to high humidities and strong radiation dose, outperforming the commercial scintillator CsI:Tl. This result paves the way for developing new scintillator and enriches the compound of europium-bearing organic framework with X-ray scintillating luminescence.