Scintillator Screen Research Articles

Novel, Green, and Scalable Aqueous Synthesis of Yellow–Green Emitting Cs3Cu2Cl5 Scintillator and its Application in High‐Resolution TFT Panel for X‐Ray Imaging Detector

AbstractCopper‐based metal halide scintillators have received increasing attention due to their high light yield and nontoxicity. However, the synthetic methods are still not feasible for actual commercialization for the difficulty in scaling up and the absence of green chemical footprint. Herein, we report a new, simple, aqueous synthetic method for the mass production of highly purified and crystallized Cs3Cu2Cl5 powder by a room‐temperature reaction between a saturated aqueous solution of CsCl and a saturated hydrochloric acid solution of CuCl. The product exhibits a photoluminence peak centering at 527 nm (FWHM = 106.7 nm) and a quantum yield (PLQY) of 97%. A prototype X‐ray imaging detector is fabricated by coupling a large area scintillation screen prepared by blade coating of Cs3Cu2Cl5 powder and a commercial thin‐film transistor (TFT) panel (16 cm × 13 cm, 125 µm pixel size) with readout circuit. The device exhibits a high spatial resolution of 4 lp mm−1, exceeding the theoretical limit of the TFT panel, and an excellent dynamic imaging ability. In short, this work demonstrates an efficient novel synthetic method of Cs3Cu2Cl5 and its application as X‐ray imaging device, providing an applicable solution for its future commercialization.

Flexible and Transparent Ceramic Nanocomposite for Laboratory X-ray Imaging of Micrometer Resolution.

Transparent nanocomposites have attracted considerable attention in many areas including X-ray imaging, wearable electronics, and volumetric display. However, both the transparency and the flexibility were largely jeopardized by the loading content of functional nanoparticles (NPs), posing a major challenge to material engineering. Herein, an ultra-high-loading-ceramic nanocomposite film was fabricated by a blade-coating technique. The film exhibited a high transparency over ∼89% in the whole visible region even with a fluoride-ceramic content up to ∼83 wt %. Based on a real-time investigation on the formation process of the film, the refractive-index difference between the nanoparticles and matrix was identified as the dominating factor to transparency. The transmittance spectra based on Rayleigh scattering theory were simulated to screen both nanoparticle radius and loading content, leading to the discovery of a transparency zone for film making. As a proof-of-concept experiment, the transparent film was used as an X-ray scintillation screen, which exhibited a comparable light yield to that of LYSO owing to the mitigated self-absorption effect. The homemade imager demonstrated a spatial resolution of 122 lp/mm, representing a record resolution of 4.1 μm for laboratory X-ray photography. Our work not only provided an experimental procedure to make high-loading functional films but also demonstrated a theoretical model to guide the search for gradients of transparent composites.

Ceramic Wafer Scintillation Screen by Utilizing Near‐Unity Blue‐Emitting Lead‐Free Metal Halide (C8H20N)2Cu2Br4

AbstractScintillators with high light yield, low detection limit, large X‐ray attenuation efficiency as well as stable and nontoxic compositions are of great importance for radiation detection applications. Here, 0D (C8H20N)2Cu2Br4 single crystals are obtained and show blue emission peaking at 468 nm with a near‐unity photoluminescence quantum yield of 99.7%, a large Stokes shift of 148 nm (i.e., negligible self‐absorption), and a good environmental stability along with strong X‐ray absorption capability. Moreover, a high light yield of up to ≈ 91 300 photons/MeV and a low detection limit of 52.1 nGyair s−1 are realized, which is more than one hundred times lower than the dose rate of 5.5 µGyair s−1 required for X‐ray medical diagnostics. (C8H20N)2Cu2Br4 ceramic wafer scintillation screen is fabricated by a cold pressing sintering process, and the clear contrast images of opaque metal box and electronic component with a spatial resolution of 9.54 lp mm−1 are realized. This study not only designs a new lead‐free metal halide scintillator, but also develops a universal strategy for the preparation of large‐sized scintillator screen in nondestructive X‐ray imaging.

One-pot synthesis of lanthanide-activated NaBiF4 nanoscintillators for high-resolution X-ray luminescence imaging

Nanocrystal scintillators have attracted considerable attention due to their attractive facile solution-processed thin-film fabrication and tunable X-ray luminescence, and thus hold promise for manufacturing next-generation scintillation screens for high-resolution X-ray imaging. Current inorganic scintillators usually have drawbacks of time-consuming preparation, toxic components, and rigorous synthesis conditions at a relatively high temperature. Here, we report a one-pot green synthesis strategy for readily scaling-up preparation of eco-friendly, lanthanide-doped NaBiF4 nanoscintillators. These nanoscintillators feature efficient X-ray absorption due to the high-Z bismuth element and tunable radioluminescence in the visible region through rational lanthanide doping. We demonstrate a laminating-annealing technology to fabricate large-area scintillation screen (Ø = 5 cm) using these NaBiF4 nanoscintillators for high-resolution X-ray imaging with a spatial resolution of 9 line pairs per millimeter (lp mm−1). Our study offers new ways to transport low-cost synthesis of high-quality nanoscintillators for high-performance digital radiography.

High-throughput production of LuAG-based highly luminescent thick film scintillators for radiation detection and imaging

Radiography is non-destructive imaging for engineering, medical diagnostics, airport security checks, and decontamination activities in nuclear plants. Inorganic scintillators are phosphor materials that convert radiation into visible photons with high luminescence and fast response, and scintillators with a few tens of micrometers thickness can improve sensitivity in radiation detection and imaging. To date, a production method for thick film scintillators is a time and cost consuming way of slicing and poshing bulk single crystals and transparent ceramics. Here, the chemically vapor deposited Ce3+-doped Lu3Al5O12 thick film scintillators (CVD-Ce3+:LuAG) with a thickness of 1–25 μm were produced at deposition time of 1–30 min. Numerical simulations indicated the penetration depth of α-particle in Ce3+:LuAG is 12.8 μm, and the 14-μm-thick CVD-Ce3+:LuAG showed highest light yield (31,000 photons 5.5 MeV−1), superior to the commercial Ce3+:LuAG single crystal scintillator (21,000 photons 5.5 MeV−1). In the X-ray radiograph taken with CVD-Ce3+:LuAG as a scintillation screen, 5-μm-width bar of metal microgrids can be identified. Vapor deposition technique can be a novel high-throughput production way of a thick film scintillator which is in a micrometer-thickness effective to converting radiations into photons for sensitive α-emitter detection and high-resolution X-ray imaging.

Large-area flexible scintillator screen based on copper-based halides for sensitive and stable X-ray imaging

X-ray scintillators, which convert high-energy radiation into visible light signals, have been rapidly developed for their widespread use in medical, security, and commercial diagnostic technologies. However, the development of large-area flexible scintillator screens with excellent stability and scintillation performance for non-planar objects is relatively lagging behind. Here, we fabricated large-area flexible scintillator screens with excellent stability and scintillation properties by loading nanoscale Cs3Cu2I5 particles into an elastic polydimethylsiloxane (PDMS) matrix. Copper halide Cs3Cu2I5, with self-trapped exciton emission, exhibits intense blue emission with a large Stokes shift, which can effectively reduce the light self-absorption effect. The experimental results reveal that the PDMS matrix can effectively passivate the surface defects of Cs3Cu2I5 particles, improve the exciton binding energy and ensure effective exciton recombination, thereby achieving more efficient optical coupling efficiency. In addition, the Cs3Cu2I5@PDMS flexible film exhibits excellent thermal stability, photostability, and water stability, and the radiative luminescence intensity does not decay after a continuous irradiation for 100 min under high-dose X-rays. Large-area flexible scintillator screen with uniform luminescence achieves a high spatial resolution of 8.6 lp/mm and a high light yield of 46000 photons/MeV, and exhibits excellent linear response to X-ray dose rate and low detection limit of 96.54 nGyair/s. Moreover, the large-area flexible scintillator screen exhibits high-quality X-ray imaging for both planar and non-planar objects. Our results demonstrate that the stable and sensitive Cs3Cu2I5@PDMS scintillator screen may have promising application prospects in flexible X-ray imaging fields.

Triplet-triplet energy-transfer-based transparent X-ray imaging scintillators

<h2>Summary</h2> In this work, we fabricated a highly efficient and reabsorption-free transparent X-ray imaging scintillator with high performance using an efficient triplet-triplet energy transfer strategy between thermally activated delayed fluorophore (TADF-Br) and iridium organometallic complex (Ir-OMC). Steady-state and ultrafast time-resolved experiments—supported by high-level density functional theory calculations—clearly demonstrate that efficient triplet-triplet energy transfer from TADF-Br with a high X-ray absorption cross-section to emissive Ir-OMC can be achieved. Such high efficiency of interfacial triplet energy transfer and the heavy atoms in both the donor and acceptor led to a remarkable enhancement in triplet-state radioluminescence upon X-ray irradiation. The fabricated X-ray imaging scintillator achieved an X-ray imaging resolution of 19.8 lp mm⁻¹, exceeding the resolution of most reported organic and organometallic scintillation screens.

Detector challenges of the strong-field QED experiment LUXE at the European XFEL

The LUXE experiment aims at studying high-field QED in electron–laser and photon–laser interactions, with the 16.5 GeV electron beam of the European XFEL and a laser beam with power of up to 350 TW. The experiment will measure the spectra of electrons, positrons and photons in the expected range of 10−3 to 109 per 1 Hz bunch crossing, depending on the laser power and focus. These measurements have to be performed in the presence of low-energy high radiation-background. To meet these challenges, for high-rate electron and photon fluxes, the experiment will use Cherenkov radiation detectors, scintillator screens, sapphire sensors as well as lead-glass monitors for backscattering off the beam-dump. A four-layer silicon-pixel tracker and a compact electromagnetic tungsten calorimeter with GaAs sensors will be used to measure the positron spectra. The layout of the experiment and the expected performance under the harsh radiation conditions, together with the test of the Cherenkov detector and the electromagnetic (EM) calorimeter performed recently at DESY, are presented. The experiment received a stage 0 critical approval (CD0) from the DESY management and is in the process of preparing its technical design report (TDR). It is expected to start running in 2025/2026.

Thermally Activated Delayed Fluorescence Zirconium-Based Perovskites for Large-Area and Ultraflexible X-ray Scintillator Screens.

Flexible scintillator screens with environmental stability, high sensitivity, and low cost have emerged as candidates for X-ray imaging applications. Here, a large-scale and cost-efficient solution synthesis of the vacancy-ordered double perovskite Cs2 ZrCl6 , which is characterized by thermal activation delayed fluorescence (TADF) dominated by triplet emission under X-ray irradiation, is demonstrated. The large Stokes shift and efficient luminescence collection of TADF effectively ensure the light outcoupling efficiency. Further, flexible X-ray scintillator screens with an area of 400 cm2 are prepared using poly(dimethylsiloxane) (PDMS) as the carrier, exhibitingexcellent scintillation properties with light yields as high as 49400 photons MeV-1 , spatial resolutions up to 18 lp mm-1 and detection limits as low as 65 nGy s-1 . Finally, the high-quality imaging results of non-planar and dynamic objects by such screens are demonstrated. It is believed that the explored Cs2 ZrCl6 @PDMS flexible scintillator screens would offer a big step toward expanding the application range of scintillators in different environments.

Performance of borated scintillator screens for high-resolution neutron imaging

The most commonly used screens for neutron imaging consist of 6LiF + ZnS. This type of screen yields the highest light output per detected neutron. For high resolution, gadolinium oxysulfide (GOS, Gadox) screens are employed, which have a much higher detection efficiency, but a light output so much lower than LiF + ZnS that measurements are often limited by photon statistics. Historically, screens using boron as a neutron-sensitive material have not been very successful. However, a new preparation method was introduced recently that produces light output higher than Gadox with detection efficiency greater than LiF + ZnS. Measurements of these new borated screens were performed at the NeXT facility at ILL, Grenoble, in comparison to a high resolution Gadox screen.

Effect of the Synthesis Conditions on the Morphology, Luminescence and Scintillation Properties of a New Light Scintillation Material Li2CaSiO4:Eu2+ for Neutron and Charged Particle Detection

In the present article, the influence of the activator concentration and impurity content of raw materials on the luminescence and scintillation properties of Li2CaSiO4 was studied. Polycrystalline powder material was obtained by the sol–gel method. It was shown that europium had limited solubility in the host lattice with a limiting concentration proximate to 0.014 formula units. The maximum intensity of photoluminescence was observed with a divalent europium concentration of 0.002 formula units; the light yield under alpha-particle excitation was measured to be 21,600 photons/MeV for ~200 μm of coating, and under neutron excitation, it was calculated to be 103,800 photons/n, the scintillation kinetics was characterized by an effective decay time of 157 ns. These properties and the transparency in the visible spectrum make it possible to produce scintillation screens with a coating of Li2CaSiO4 for detecting neutrons, alpha particles and low-energy beta radiation. The low Zeff (~15) of this compound makes it less sensitive to gamma rays. The 480 nm blue emission peak makes this material compatible with most commercial PMT photocathodes, CCD cameras and silicon photomultipliers, which have a maximum quantum efficiency in the blue–green spectral region.

Micrometer-Resolution X-ray Imaging Enabled by a Flexible Perovskite Screen.

Spatial resolution improvement has been keenly sought recently in the perovskite-based scintillation community. Here, micrometer resolution (∼2.0 μm) was achieved by using an X-ray imaging screen of self-assembled perovskite nanosheets. The assembly behavior of nanosheets was applicable to many substrates, including glass, metal, and polymer surfaces. The use of a polymer substrate not only eliminated the parasite absorption of X-ray but also enabled a flexible screen with robust bending stability. The assembly behavior, on the other hand, provided vicinity for an efficient energy transfer between nanosheets of varied thicknesses, as evidenced by both transient absorption and photoluminescence lifetime measurements. Importantly, the ensuing large Stokes shift (∼316 meV) significantly mitigated the reabsorption issue, leading to a comparable light yield to LYSO/Ce crystals. With the aid of the synchrotron-based collimated X-ray beam, the fine structure of two-dimensional objects, such as microchips, was clearly visualized with the flexible scintillation screen. Furthermore, those challenging biological samples were also scanned by phase-contrast imaging, whereby a three-dimensional reconstruction was obtained successfully. Despite the labile nature of the perovskite screen, this work represents the state-of-the-art spatial resolution for perovskite scintillation.

P43 for manufacturing of large area scintillating screens

This paper describes investigation of scintillator P43 coating for large area screens intended for preliminary beam diagnostics in the Collector Ring (Facility for Antiproton and Ion Research in Europe). We used two appropriate coating techniques: detonation spraying and electrophoresis. The article contains short descriptions of the Collector Ring, screen coating techniques, light output (with application of electron welding), and vacuum tests. We also applied SEM to check the structure and chemical composition of pure P43 powder and scintillation screen samples, prepared by detonation spraying and electrophoresis coating techniques. As a result, we observed poor P43 light output after detonation spraying (the reason is a change in the chemical composition of P43) and poor ruby and alumina light output in comparison with P43 in the case of the electrophoresis technique. Improving of the electrophoresis technique enabled us to reach good adhesion and vacuum properties without decrease in the light yield.

Performance of a scintillation imaging system for relative dosimetry in pencil beam scanning proton therapy

The proton spot scanning system requires extensive periodic quality assurance procedures to guarantee the conformality of planned dose distribution to the tumor. Detectors with stable, accurate, and fast data acquisition properties make the quality assurance procedures more efficient. For this purpose, a camera-based scintillation imaging system has been developed. A high scintillation efficiency screen coupled with a high-performance camera improved the dose sensitivity and precision required for the measurements. The dose distribution within the scintillating screen can be analyzed from the captured light distribution image in a relatively straightforward way.In this study, we investigated the performance of a 2D detection system by using a scintillating screen (silver-activated zinc sulfide powder deposited on the surface of a plastic scintillator HND-S2) for dose distribution measurement. The characteristics of the system in terms of response reproducibility, linear dose–response, and beam spot size dependence on proton dose were assessed in a series of proton irradiations. To evaluate the accuracy of lateral dose profiles measured by the ZnS: Ag based scintillating screen, we compared the results with plastic scintillator BC-408 and some commercial quality control devices. Several measurements were conducted with proton energies ranging from 70–235 MeV. We found that the detector showed stable response reproducibility (better than 1.6%) and good dose–response linearity (R2¿0.999). The beam spot size was independent of proton dose when the response of the pixel value was between 10% and 90% of the maximum. The in-air spot size measured by the ZnS: Ag based scintillating screen was found to be slightly smaller than the Lynx detector while the BC-408 showed a slightly bigger spot size. The inter-comparison results for scanned fields showed good agreements. The observed differences in beam profile measurement between the inorganic and organic scintillating screens were mainly due to their optical properties and structures. The developed scintillation imaging system with an effective resolution of 0.12 mm proved to be a reliable device for efficiently performing the quality checks for two-dimensional proton dosimetry.

In Situ Preparation of High‐Quality Flexible Manganese‐Halide Scintillator Films for X‐Ray Imaging

AbstractEnvironmentally friendly metal halides have emerged as emitters in lighting and X‐ray imaging applications. However, the conventional scintillator fabrication process involves high‐temperature sintering or powder grinding, resulting in large bulk crystals or agglomerates, which hamper flexible device integration and processability. Here, large‐area flexible scintillation screen films containing (C24H20P)2MnBr4 nanocrystals are prepared in situ, which prevents the generation of agglomerated powders or large bulk crystals, and the preparation duration and cost are reduced. The film exhibits good mechanical stability and homogeneity, and the photoluminescence quantum yield is over 85%. Moreover, the film presents excellent scintillation performance with detection limit as low as 0.608 μGyair s−1 and 14.5 lp mm−1 X‐ray imaging resolution. This excellent performance and simple preparation method are expected to favor industrial mass production.

Highly efficient blue emissive copper halide Cs5Cu3Cl6I2 scintillators for X-ray detection and imaging

In recent years, copper-based halide scintillators have attracted tremendous attention due to their excellent luminescent properties and low manufacturing costs. Herein, a high-performance and low-cost Cs5Cu3Cl6I2 scintillator is prepared by simple mechanical grinding. The mixed-halide Cs5Cu3Cl6I2 phosphor exhibits a blue emission centered at 475 nm with a large stokes shift, originating from the self-trapped exciton emission of Cu sites. The photoluminescence quantum yield (PLQY) of Cs5Cu3Cl6I2 can be increased to 88.4% from 20.4% by the efficient suppression of the anion vacancy defects. In addition, the Cs5Cu3Cl6I2 scintillator shows a high steady-state X-ray to light conversion efficiency of about 57000 photons/MeV, good X-ray linear response, and low detection limit of 71.9 nGyair/s. The X-ray imaging results based on the Cs5Cu3Cl6I2 scintillator screen display a high spatial resolution of 9.0 line-pairs per millimeter (lp/mm). Furthermore, Cs5Cu3Cl6I2 exhibits good radiation stability under a total dose of 113.58 Gyair. Overall, the Cs5Cu3Cl6I2 scintillator prepared by mechanical grinding method has the advantages of low cost, high efficiency, and good radiation resistance, suggesting its huge potential in X-ray detection and imaging.

Luminescence and Structural Characterization of Gd2O2S Scintillators Doped with Tb3+, Ce3+, Pr3+ and F for Imaging Applications

Radiodiagnostic technologies are powerful tools for preventing diseases and monitoring the condition of patients. Medicine and sectors such as industry and research all use this inspection methodology. This field demands innovative and more sophisticated systems and materials for improving resolution and sensitivity, leading to a faster, reliable, and safe diagnosis. In this study, a large characterization of gadolinium oxysulfide (Gd2O2S) scintillator screens for imaging applications has been carried out. Seven scintillator samples were doped with praseodymium (Pr3+), terbium (Tb3+) activators and co-doped with praseodymium, cerium, and fluorine (Gd2O2S:Pr,Ce,F). The sample screens were prepared in the laboratory in the form of high packing density screens, following the methodology used in screen sample preparation in infrared spectroscopy and luminescence. Parameters such as quantum detection efficiency (QDE), energy absorption efficiency (EAE), and absolute luminescence efficiency (ALE) were evaluated. In parallel, a structural characterization was performed, via XRD and SEM analysis, for quality control purposes as well as for correlation with optical properties. Spatial resolution properties were experimentally evaluated via the Modulation Transfer Function. Results were compared with published data about Gd2O2S:Pr,Ce,F screens produced with a standard method of a sedimentation technique. In particular, the ALE rose with the X-ray tube voltage up to 100 kVp, while among the different dopants, Gd2O2S:Pr exhibited the highest ALE value. When comparing screens with different thicknesses, a linear trend for the ALE value was not observed; the highest ALE value was measured for the 0.57 mm thick Gd2O2S:Pr,Ce,F sample, while the best MTF values were found in the thinner Gd2O2S:Pr,Ce,F screen with 0.38 mm thickness.

Influence of the thickness of a SiO2 reflective layer on the performance of a structured CsI(Tl) scintillation screen based on an oxidized Si micropore array template in X-ray imaging.

To obtain better light guidance and optical isolation effects under a limited microcolumn wall thickness, the influence of the thickness of a SiO2 reflective layer on the performance of a structured CsI(Tl) scintillation screen based on an oxidized Si micropore array template in X-ray imaging was simulated. The results show that the SiO2 reflective layer should maintain a certain thickness to achieve good light-guide performance. However, if the template is entirely composed of SiO2, the light isolation performance of the microcolumn wall will be slightly worse. The results provide a basis for optimizing the thickness of SiO2 reflective layer.

Influence of Si wall thickness of CsI(Tl) micro-square-frustums on the performance of the structured CsI(Tl) scintillation screen in X-ray imaging

To improve the detection efficiency of the structured scintillation screen with CsI(Tl) micro-square-frustums based on oxidized Si micropore array template in the case of a period as small as microns, the influence of Si wall thickness of the CsI(Tl) micro-square-frustums on the performance of the structured screen in X-ray imaging was investigated. The results show that when CsI(Tl) at the bottom of the screen is structured, the detective quantum efficiency (DQE) improves at almost all spatial frequency as the top thickness of the Si wall tSi decreases. However, when CsI (Tl) at the bottom of the screen is not structured, the DQE becomes better at low-frequency and worse at high-frequency as tSi decreases. The results can provide guidance for optimizing tSi according to the comprehensive requirements of detection efficiency and spatial resolution in X-ray imaging.

Organic room-temperature phosphorescent polymers for efficient X-ray scintillation and imaging

Materials that exhibit visible luminescence upon X-ray irradiation show great potential in the medical and industrial fields. Pure organic materials have recently emerged as promising scintillators for X-ray detection and radiography, due to their diversified design, low cost, and facile preparation. However, recent progress in efficient radioluminescence has mainly focused on small molecules, which are inevitably associated with processability and repeatability issues. Here, a concise strategy is proposed to prepare radioluminescent polymers that exhibit multiple emission colors from blue to yellow with high brightness in an amorphous state by the radical copolymerization of negatively charged polyacrylic acid and different positively charged quaternary phosphonium salts. One of the obtained polymers exhibits excellent photostability under a high X-ray irradiation dosage of 27.35 Gy and has a detection limit of 149 nGy s − 1. This performance is superior to that of conventional anthracene-based scintillators. Furthermore, by simply drop-casting a polymer methanol solution on a quartz plate, a transparent scintillator screen was successfully fabricated for X-ray imaging with a resolution of 8.7 line pairs mm − 1. The pure organic phosphorescent polymers with a highly efficient radioluminescence were demonstrated for the first time, and the strategy reported herein offers a promising pathway to expand the application range of amorphous organic scintillators.