Scintillator Screen Research Articles

Large-Area Transparent Antimony-Based Perovskite Glass for High-Resolution X-ray Imaging.

Nonlead low-dimensional halide perovskites attract considerable attention as X-ray scintillators. However, most scintillation screens exhibit pronounced light scattering, which detrimentally reduces the quality of X-ray imaging. Herein, we employed a simple and straightforward solvent-free melt-quenching method to fabricate a large-area zero-dimension (0D) antimony-based perovskite transparent medium, namely (C20H20P)2SbCl5 (C20H20P+ = ethyltriphenylphosphine). The transparency is due to the large steric hindrance of C20H20P+, which hinders the formation of crystals during the quenching process, thus forming a glass with low refractive index and uniform structure. This medium exhibits a high transmittance exceeding 80% in the range of 450-800 nm and shows a large Stokes shift of 245 nm, thereby minimizing light scattering, mitigating self-absorption, and enhancing the clarity of X-ray imaging. Moreover, it exhibits a high radioluminescence light yield of ∼12,535 photons MeV-1 and displays a high X-ray spatial resolution of 30 lp mm-1 owing to its high transparency. This study presents an alternative candidate for achieving high-quality X-ray detection and extends the applicability of transparent perovskite scintillators.

Photoluminescence-Tunable organic phosphine cuprous halides clusters for X-ray scintillators and white light emitting diodes

Low-dimensional cuprous clusters demonstrate fascinating luminescent properties due to their uniquely diversified charge transfer excited states, which imply it could be ideal candidate for multifunctional applications, such as X-ray scintillators and white light emitting diodes (WLED). However, it is still challenge for low-dimensional cuprous clusters that how to regulate the emission performance to meet the requirements of the specific applications. In this work, we prepared a series of luminescent organic cuprous iodide clusters, (IPP)CuI2 and (IPP)2CuI3, which show tunable emission property by simply component regulation. The (IPP)CuI2 with IPP: CuI = 1: 0.75 show the best scintillator property with super-low detection limit of 62.29 nGy/s and high light yields of 75793.83 photons/MeV which is far beyond most organic copper halide scintillators. A series of clear digital radiography (DR) with high spatial resolution of 10.2 lp/mm and a reconstructed 3D model based on computed tomography (CT) were successfully obtained by the prepared scintillation screen. Moreover, the single-component WLED based on accurately component regulation (IPP)CuI2 with IPP: CuI = 1: 0.99 exhibits pure white emission with a high CRI (color rendering index) of 82. The luminescence mechanism of charge transfer excited states in tunable emission (IPP)CuI2 was also investigated. Our works not only provide a kind of ideal materials applied for high-performance single-component WLED and scintillator but also reveal the large potential of low-dimensional organic cuprous halides as luminescent material for multifunctional applications.

High-light-yield and fast-response β-Ga2O3–Al2O3 thick-film scintillators epitaxially grown via chemical vapor deposition

β-gallia (β-Ga2O3) has been investigated for adoption in power semiconductor wafers; however, it is a promising scintillating material for X-ray detection screens. Thus, the research on methods for growing β-gallia crystals has attracted considerable attention. Herein, 15-μm thick Ga2O3–Al2O3 solid solution films with β-gallia structure were synthesized using metal–organic chemical vapor deposition (CVD) at deposition rate of 15 μm h−1. A high scintillation light yield of 5400 photons per 5.5 MeV and a fast decay response of 5.1 ns of the produced films were observed, which were comparable or superior to those of the β-Ga2O3 single crystals. CVD method proved advantageous for the rapid synthesis of micrometer-thick Ga2O3-based scintillation screens.

Exploring crucial technological advancements in Anger-Camera neutron detectors for single crystal neutron diffraction

In accordance with the second phase construction blueprint for the China Spallation Neutron Source (CSNS-II), the proposal includes the establishment of a single crystal neutron diffractometer. This apparatus necessitates a neutron detector array spanning over 1 m2 and capable of covering neutron diffraction angles from 20° to 160°. Additionally, the detector's position resolution must better than 1 mm × 1 mm. To meet such requirements, a scintillator neutron detector based on the Anger-Camera principle was designed. The detector is composed of a 6LiF/ZnS (Ag) scintillation screen, optical guide, silicon photomultipliers (SiPMs) array and self-design composite compression readout electronic systems. A detector prototype, featuring a detection area of 50 mm × 50 mm, was fabricated and subjected to testing at the BL20 neutron test line in the China Spallation Neutron Source (CSNS). The detector system achieved an optimal position resolution of 0.6 mm, while the maximum count rate was approximately 20 kHz. Moreover, the detector's Bragg edge imaging capability was preliminarily investigated using stainless steel samples, demonstrating its future potential for Bragg edge transmission imaging. The proposed detector demonstrates promising potential as a candidate for the single crystal diffractometer in CSNS-II.

Probing Energy‐Funneling Kinetics in Nanocrystal Sublattices for Superior X‐Ray Imaging

AbstractLong‐lasting radioluminescence scintillators have recently attracted substantial attention from both research and industrial communities, primarily due to their distinctive capabilities of converting and storing X‐ray energy. However, determination of energy‐conversion kinetics in these nanocrystals remains unexplored. Here we present a strategy to probe and unveil energy‐funneling kinetics in NaLuF4:Mn2+/Gd3+ nanocrystal sublattices through Gd3+‐driven microenvironment engineering and Mn2+‐mediated radioluminescence profiling. Our photophysical studies reveal effective control of energy‐funneling kinetics and demonstrate the tunability of electron trap depth ranging from 0.66 to 0.96 eV, with the corresponding trap density varying between 2.38×105 and 1.34×107 cm−3. This enables controlled release of captured electrons over durations spanning from seconds to 30 days. It allows tailorable emission wavelength within the range of 520–580 nm and fine‐tuning of thermally‐stimulated temperature between 313–403 K. We further utilize these scintillators to fabricate high‐density, large‐area scintillation screens that exhibit a 6‐fold improvement in X‐ray sensitivity, 22 lp/mm high‐resolution X‐ray imaging, and a 30‐day‐long optical memory. This enables high‐contrast imaging of injured mice through fast thermally‐stimulated radioluminescence readout. These findings offer new insights into the correlation of radioluminescence dynamics with energy‐funneling kinetics, thereby contributing to the advancement of high‐energy nanophotonic applications.

Probing Energy-Funneling Kinetics in Nanocrystal Sublattices for Superior X-Ray Imaging.

Long-lasting radioluminescence scintillators have recently attracted substantial attention from both research and industrial communities, primarily due to their distinctive capabilities of converting and storing X-ray energy. However, determination of energy-conversion kinetics in these nanocrystals remains unexplored. Here we present a strategy to probe and unveil energy-funneling kinetics in NaLuF4:Mn2+/Gd3+ nanocrystal sublattices through Gd3+-driven microenvironment engineering and Mn2+-mediated radioluminescence profiling. Our photophysical studies reveal effective control of energy-funneling kinetics and demonstrate the tunability of electron trap depth ranging from 0.66 to 0.96 eV, with the corresponding trap density varying between 2.38×105 and 1.34×107 cm-3. This enables controlled release of captured electrons over durations spanning from seconds to 30 days. It allows tailorable emission wavelength within the range of 520-580 nm and fine-tuning of thermally-stimulated temperature between 313-403 K. We further utilize these scintillators to fabricate high-density, large-area scintillation screens that exhibit a 6-fold improvement in X-ray sensitivity, 22 lp/mm high-resolution X-ray imaging, and a 30-day-long optical memory. This enables high-contrast imaging of injured mice through fast thermally-stimulated radioluminescence readout. These findings offer new insights into the correlation of radioluminescence dynamics with energy-funneling kinetics, thereby contributing to the advancement of high-energy nanophotonic applications.

Novel high-efficiency 2D position-sensitive ZnS:Ag/6LiF scintillator detector for neutron diffraction

Scintillator-based ZnS:Ag/6LiF neutron detectors have been under development at ISIS for more than three decades. Continuous research and development aim to improve detector capabilities, achieve better performance and meet the increasingly demanding requirements set by neutron instruments. As part of this program, a high-efficiency 2D position-sensitive scintillator detector with wavelength-shifting fibres has been developed for neutron-diffraction applications. The detector consists of a double scintillator-fibre layer to improve detection efficiency. Each layer is made up of two orthogonal fibre planes placed between two ZnS:Ag/6LiF scintillator screens. Thin reflective foils are attached to the front and back scintillators of each layer to minimize light cross-talk between layers. The detector has an active area of 192 × 192 mm with a square pixel size of 3 × 3 mm. As part of the development process of the double-layer detector, a single-layer detector was built, together with a prototype detector in which the two layers of the detector could be read out separately. Efficiency calculations and measurements of all three detectors are discussed. The novel double-layer detector has been installed and tested on the SXD diffractometer at ISIS. The detector performance is compared with the current scintillator detectors employed on SXD by studying reference crystal samples. More than a factor of 3 improvement in efficiency is achieved with the double-layer wavelength-shifting-fibre detector. Software routines for further optimizations in spatial resolution and uniformity of response have been implemented and tested for 2D detectors. The methods and results are discussed in this manuscript.

Confinement of methylammonium lead bromide nanocrystals in metal–organic frameworks as a stable scintillator for high-performance X-ray imaging

The development of perovskite nanocrystals (NCs) based composites with enhanced stability and exceptional photoelectric properties is of great significance for their application in scintillators for X-ray imaging, but it remains challenging. Herein, we demonstrate a novel and stable scintillator, achieved through a host–guest strategy involving the confinement of perovskite NCs, e.g., MAPbBr3 NCs, in metal–organic frameworks (MOFs). The host MOF, bio-MOF-100 (denoted as bMOF), facilitates the in-situ space-confined formation of MAPbBr3 NCs while providing quantum confinement, surface passivation, and protection to these guests. This host–guest strategy results in high exciton binding energy, bright and efficient luminescence, and significantly enhancing their stability against various factors such as air, heat, UV, solvents and X-ray irradiation. Consequently, this advancement prompts the transition of their application scenarios from the colloidal state to the solid state. The bMOF⊃MAPbBr3 scintillator exhibits a linear response to X-ray with a detection limit determined to be 170 nGyair s−1. Moreover, the bMOF⊃MAPbBr3–PMMA scintillator screen demonstrates high-quality X-ray imaging with an impressive spatial resolution of 14.7 lp mm−1. This work provides a new avenue for the development of perovskite NCs-based host–guest composites and paves the way for the broader implementation in solid-state optoelectronic applications.

Imaging of low Z masked with high Z (Pb, U) materials using 14 MeV neutron

An experimental study has been performed using 14 MeV neutrons for imaging of low Z material (particularly composed of C, H, O elements) masked with thick layers of dense and high Z materials. The experimental setup consists of a D-T neutron generator, a metallic collimator and an imaging system. The imaging system is designed with a polypropylene zinc sulphide scintillator screen integrated with a lens coupled 16-bit ICCD camera. Imaging capability of the system was investigated using iron test samples with holes and line pair features. The minimum hole size of 2 mm could be imaged at a contrast of 36% and a line of 2 mm width visible at a contrast of 24% indicating the system's resolution of ∼ mm. Low Z samples such as water (H2O) and polyethylene (C2H2) n placed behind thick layers of Pb (40 mm) and Uranium (35 mm), were imaged successfully. These images reveal the system's ability towards low Z material imaging in the presence of heavier metals. Good contrast images acquired at a lower neutron yield of ∼ 5 × 108 n/sec of D-T neutron generator has provided a possibility to realise fast neutron imaging having moderate resolution (∼ mm) with a smaller footprint and an economical system design for field applications.

Flexible Wood‐Based X‐Ray Scintillator Film Using Lead‐Free Cs3Cu2I5 Perovskite Nanoparticles

The prevalent use of unsustainable polymers in current X‐ray scintillators poses a significant environmental concern. The advancement of biodegradable X‐ray scintillators holds promise in mitigating escalating environmental issues tied to electronic or medical waste and carbon footprints. Herein, a biodegradable and flexible X‐ray scintillation film is presented employing lead‐free 0D Cs3Cu2I5 perovskite nanoparticles integrated into densified‐delignified wood (Cs3Cu2I5@D‐Wood). The Cs3Cu2I5@D‐Wood film demonstrates precise and detailed X‐ray imaging capabilities, achieving a high spatial resolution of 10 line pairs per millimeter (lp·mm−1). To minimize the environmental impact associated with disposal, metal and halide ions (e.g., Cs+, Cu+, I−) from Cs3Cu2I5@D‐Wood can be easily retrieved by a simple solvent extraction process. The approach showcases the potential of biodegradable wood‐based X‐ray scintillation screens as alternatives to conventional, plastic‐based screens. This offers a significant contribution to environmental sustainability by reducing electronic or medical waste.

Ultrahigh X‐Ray Imaging Spatial Resolution Enabled by an 0D Mn(II) Hybrid Scintillator

AbstractSpatial resolution of scintillator is crucial for high‐quality X‐ray imaging, especially in tiny and complicated electronic component. In this work, PrPP2MnBr4 single crystal is obtained by dual‐solvent evaporation method, which gives an unprecedented high spatial resolution of 104.3 lp/mm, representingstate of the art among non‐lead metal halides. The study also conducts the preparation of large area scintillation screen (10 cm × 10 cm) by solidifying melted salt PrPP2MnBr4, thus giving an excellent X‐ray imaging with spatial resolution of 53.5 lp mm−1, which demonstrates its application on large area detection.

Manipulation of Coupled X‐Ray‐Excited Persistent Luminescence and Upconversion in Er3+ Doped Fluoride Nanoparticles for Multifaceted Applications

AbstractLanthanide doped nanoparticles (NPs) exhibit tunable X‐ray‐excited optical luminescence and X‐ray‐excited persistent luminescence (XEPL), holding broad prospects for applications in display/anti‐counterfeiting and X‐ray imaging. The development of effective strategies for multi‐dimensional applications based on lanthanide‐doped fluoride NPs are a constant challenge. Here, core–shell structured fluoride NPs, in which the heavy metal fluoride shell effectively suppresses the non‐radiative relaxation and simultaneously improve the X‐ray absorption of the shell are designed and fabricated. Under X‐ray irradiation, the developed NPs exhibit an increased number of secondary electrons which migrate to Er3+ centers at the interface and greatly improve the XEPL intensity. Additionally, the introduction of Mn2+ further enhances the XEPL intensity and offers an effective route to control the red‐green ratio of the upconversion spectrum. The NPs co‐doped with Mn2+ exhibit a bright green XEPL under X‐ray irradiation and a red emission under 1532 nm laser excitation. It is further validated that these NPs can be utilized for advanced anti‐counterfeiting and high‐resolution delayed imaging based on a film containing NPs as a scintillation screen. These findings suggest a new strategy of designing Er3+ doped NPs for multi‐dimensional applications.

Cs2NaGdCl6:Tb3+─A Highly Luminescent Rare-Earth Double Perovskite Scintillator for Low-Dose X-ray Detection and Imaging.

Rare-earth-based double perovskite (DP) X-ray scintillators have gained significant importance with low detection limits in medical imaging and radiation detection owing to their high light yield (LY) and remarkable spatial resolution. Herein, we report the synthesis of 3D double perovskite (DP) crystals, namely, Cs2NaGdCl6 and Tb3+-Cs2NaGdCl6 using hydrothermal reaction. Cs2NaGdCl6 DP single crystals exhibited a blue self-trapped exciton (STE) emission at 470 nm under ultraviolet (265 nm) excitation with a photoluminescence quantum yield (PLQY) of 8.4%. Introducing Tb3+ ions into Cs2NaGdCl6 has resulted in quenching of STE emission and enhancing green emission at 549 nm attributed to the 5D4 → 7F5 transition of Tb3+, suggesting efficient energy transfer (ET) from STE to Tb3+. This ET process is evidenced by the appearance of Tb3+ bands in the excitation spectra of the host, the shortening of the STE lifetimes in the presence of Tb3+ ions, and the enhancement of PLQY (72.6%). Furthermore, Cs2NaGdCl6:5%Tb3+ films of various thicknesses (0.1-0.6 mm) were synthesized and their X-ray scintillating performance has been examined. The Cs2NaGdCl6:5%Tb3+ film with 0.4 mm thickness has exhibited an excellent linear response to the X-ray dose rate with a low detection limit of 41.32 nGyair s-1, an LY of 39,100 photons MeV-1, and excellent radiation stability. Benefiting from the strong X-ray excited luminescence (XEL) of Cs2NaGdCl6:5%Tb3+, we developed a Cs2NaGdCl6:5%Tb3+ X-ray scintillator screen with a least thickness (0.1 mm), exhibiting remarkable imaging ability with a spatial resolution of 10.75 lp mm-1. These results suggest that Cs2NaGdCl6:Tb3+ can be a potential candidate for low-dose and X-ray imaging applications.

Who made the noise? Systematic approach for the assessment of neutron imaging scintillators

We propose a method to analyze the characteristics of scintillator screens for neutron imaging applications. Using calculations based on the theory of cascaded linear steps as well as experimental measurements, we compared the characteristics of different lithium- and gadolinium-based scintillator screens. Our results show that, despite their much lower light output, gadolinium-based scintillators outperform lithium-based scintillators in terms of noise characteristics for a variety of imaging setups. However, the relative performance of scintillator screens is highly dependent on the other setup characteristics such as the beam spectrum, field of view, used optical lens and size of the camera sensor. Consequently, the selection of the best scintillator screen – as well as the scintillator characteristics assessment in new developments – requires a systematic consideration of all these elements, as enabled by the framework presented here.

Enhanced Performance in Cesium Tellurium Chlorine by Hafnium Alloying for X‐Ray Computed Tomography Imaging

AbstractThe term “light yield” (LY) refers to the ability of scintillator materials to convert high‐energy radiation into visible light. A higher LY corresponds to improved energy and spatial resolution in detectors. The enhancement of scintillator material performance is a crucial aspect of their development. In this study, the Cs2TeCl6 (CTC) double perovskite microcrystals is synthesized, and the broadband yellow emission shows a high degree of matching with the Charge‐coupled Device (CCD). However, the LY of CTC is poor for practical applications in X‐ray imaging. The scintillation performance is significantly enhanced through hafnium alloying. The LY increased from ≈4167 to 38 523 photons/MeV, and the detection limit decreased from 948 to 258 nGy s−1. The underlying mechanism of Te4+ ions emission is systematically explored through density function theory (DFT) analysis, along with investigations into pressure‐dependent photoluminescence, temperature‐dependent photoluminescence, and low‐temperature thermoluminescence. Furthermore, a flexible X‐ray scintillator screen with an outstanding high spatial resolution of 15.9 lp mm−1 is successfully fabricated. This work not only represents a substantial advancement in the scintillation performance of Te4+ ions emission double perovskite microcrystals but also provides an effective strategy for the development of the next generation of halide scintillators.

Through‐Space Charge‐Transfer Organogold(III) Complexes Enable High‐Performance X‐ray Scintillation and Imaging

AbstractOrganic scintillators have recently attracted growing attention for X‐ray detection in industrial and medical applications. However, these materials still face critical obstacles of low attenuation efficiency and/or inefficient triplet exciton utilization. Here we developed a new category of organogold(III) complexes, Tp‐Au‐1 and Tp‐Au‐2, through adopting a through‐space interaction motif to realize high X‐ray attenuation efficiency and efficient harvesting of triplet excitons for emission. Thanks to the efficient through‐space charge transfer process, this panel of complexes achieved higher photoluminescence quantum yield and shorter radiative lifetimes compared with the through‐bond reference complexes. Inspiringly, these organogold(III) complexes exhibited polarity‐dependent emission origins: thermally activated delayed fluorescence and/or phosphorescence. Under X‐ray irradiation, Tp‐Au‐2 manifested intense radioluminescence together with a record‐high scintillation light yield of 77,600 photons MeV−1 for organic scintillators. The resulting scintillator screens demonstrated high‐quality X‐ray imaging with >16.0 line pairs mm−1 spatial resolution, outstripping most organic and inorganic scintillators. This finding provides a feasible strategy for the design of superior organic X‐ray scintillators.

Through-Space Charge-Transfer Organogold(III) Complexes Enable High-Performance X-ray Scintillation and Imaging.

Organic scintillators have recently attracted growing attention for X-ray detection in industrial and medical applications. However, these materials still face critical obstacles of low attenuation efficiency and/or inefficient triplet exciton utilization. Here we developed a new category of organogold(III) complexes, Tp-Au-1 and Tp-Au-2, through adopting a through-space interaction motif to realize high X-ray attenuation efficiency and efficient harvesting of triplet excitons for emission. Thanks to the efficient through-space charge transfer process, this panel of complexes achieved higher photoluminescence quantum yield and shorter radiative lifetimes compared with the through-bond reference complexes. Inspiringly, these organogold(III) complexes exhibited polarity-dependent emission origins: thermally activated delayed fluorescence and/or phosphorescence. Under X-ray irradiation, Tp-Au-2 manifested intense radioluminescence together with a record-high scintillation light yield of 77,600 photons MeV-1 for organic scintillators. The resulting scintillator screens demonstrated high-quality X-ray imaging with >16.0 line pairs mm-1 spatial resolution, outstripping most organic and inorganic scintillators. This finding provides a feasible strategy for the design of superior organic X-ray scintillators.

Quantifying neutron scintillator screens with X-ray computed tomography

As nondestructive imaging techniques become more commonplace, imaging systems must be improved and optimized to meet the growing demand. One key aspect of neutron imaging systems is the scintillator, which determines the time necessary to acquire an image and can also limit the spatial resolution achievable by a system. In this work, X-ray computed tomography was coupled with image processing to measure parameters of a boron-based neutron scintillator screen. The screen's surface and subsurface were examined for defects and a thickness measurement as a function of position was also successfully implemented. Higher resolution scans of a sub-volume of the scintillator coating enabled visualization of the packing of the converter and phosphor powders while also revealing microscopic porosity within the scintillator material. The converter-to-phosphor ratio was quantified with the examined area showing a ZnS:Ag phosphor volume of approximately 60.70% of the entire scintillator volume, while Na10B5O8 converter accounted for approximately 38.76% of the volume.

Water-dispersible X-ray scintillators enabling coating and blending with polymer materials for multiple applications

Developing X-ray scintillators that are water-dispersible, compatible with polymeric matrices, and processable to flexible substrates is an important challenge. Herein, Tb3+-doped Na5Lu9F32 is introduced as an X-ray scintillating material with steady-state X-ray light yields of 15,800 photons MeV−1, which is generated as nanocrystals on halloysite nanotubes. The obtained product exhibits good water-dispersibility and highly sensitive luminescence to X-rays. It is deposited onto a polyurethane foam to afford a composite foam material with dose-dependent radioluminescence. Moreover, the product is dispersed into polymer matrixes in aqueous solution to prepare rigid or flexible scintillator screen for X-ray imaging. As a third example, it is incorporated multilayer hydrogels for information camouflage and multilevel encryption. Encrypted information can be recognized only by X-ray irradiation, while the false information is read out under UV light. Altogether, we demonstrate that the water-dispersible scintillators are highly promising for aqueous processing of radioluminescent, X-ray imaging, and information encrypting materials.

Low-energy ion beam diagnostics: an integrated solution

High gradient accelerator injectors have been widely studied throughout the world-leading accelerator facilities. The demand for high frequency cavities has led the Detector, Accelerator and instrumentation laboratory (KAHVELab) in Istanbul to deploy a four-vane Radio Frequency Quadrupole (RFQ) operating at 800 MHz to accelerate 20 keV protons to 2 MeV. The protons from the microwave discharge ion source are transversely matched to the RFQ via an optimized Low Energy Beam Transport (LEBT) line which also contains an integrated measurement station, called measurement station (MBOX). The MBOX is used to measure the proton beam's current along with pulse length duration, profile as well as the beam emittance upstream of the RFQ. It contains a number of home-built diagnostic tools: a Faraday cup, a scintillator screen and a pepper pot plate (PP). The analysis software is also locally developed and tested for the PP photo analysis. In this note, the design, construction and tests of the integrated measurement station are discussed. The results from various measurements, especially on beam profile and charge, are compared to the simulation predictions.