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Metal halide crystals are bright but hygroscopic scintillator materials that are widely used in X‐ray imaging and detectors. Precipitating them in situ in glass to form glass ceramics (GCs) scintillator offers an efficient avenue for large‐scale preparation, high spatial resolution, and excellent stability. However, precipitating a high fraction of metal halide nanocrystals in glass to maintain high light yield remains a challenge. Herein, an ionic‐covalent hybrid network strategy for constructing GCs scintillator with high crystallinity (up to ≈37%) of BaCl2: Eu2+ nanocrystals is presented. Experimental data and simulations of glass structure reveal that the Ba2+‐Cl− clustering promotes the high crystallization of BaCl2 nanocrystals. The ultralow phonon energy (≈200 cm−1) of BaCl2 nanocrystals and good Eu reduction effect enable high photoluminescence inter quantum efficiency (≈80.41%) in GC. GCs with varied crystallinity of BaCl2: Eu2+ nanocrystals demonstrate efficient radioluminescence and tunable scintillator performance. They either outperform Bi4Ge3O14 single crystal by over 132% steady‐state light yield or provide impressive X‐ray imaging resolutions of 20 lp mm−1. These findings provide a new design strategy for developing bright transparent GCs scintillators with a high fraction of metal halide nanocrystals for X‐ray high‐resolution imaging applications. [ABSTRACT FROM AUTHOR]

Scintillators are used not only as single crystals in radiation detection systems but also as arrays, columns, and fibers. In this study, a novel optical-guiding crystal scintillator (OCS) was fabricated using an Eu:SrI 2 crystal as the core and borosilicate glass as the cladding. The OCS has an elongated shape and can be flexibly processed like an optical fiber. Furthermore, because inorganic scintillator crystals are used as the core, the OCS has high sensitivity to high-energy radiation, such as γ- and X-ray radiation, unlike plastic scintillators. In this study, by observing the cross section of the fabricated OCS, identifying the crystal structure, and investigating the radioluminescence spectrum under X-ray irradiation, OCS fabrication in accordance with the OCS design specifications was confirmed, and the SrI 2 crystal structure and Eu2+ 5d–4f luminescence were maintained. The γ-ray responses, such as light yield and decay time, were also investigated. [ABSTRACT FROM AUTHOR]

Alkali metal halides have long been used as scintillators for applications as sensors and detectors. Usually, a small amount of impurities are added to these inorganic materials to improve their luminescence efficiencies. We investigate the structures and luminescent properties of un-doped sodium iodide (NaI) and cesium-doped NaI (NaI:Cs) films deposited by thermal vacuum evaporation. Instead of using the toxic element thallium (Tl), we introduced cesium dopant into NaI. This is the first study for the NaI:Cs film excited by UV LED's ultraviolet C (273 nm, 4.54 eV). The luminescence spectra show two main peaks at 3.05 and 4.32/3.955 eV (for fused silica/B270 substrate), originating from the intrinsic defects and/or activator excited states and the intrinsic self-trapped excitons (STEs), respectively. In general, both Cs-doping and post-annealing processes enhance the luminescence performance of NaI films. [ABSTRACT FROM AUTHOR]

The technological aspects of the light inorganic crystalline compounds suitable to create scintillation materials to detect charged particles and neutrons in a wide energy range have been examined. Among them, Li2CaSiO4:Eu was found to be a prospective candidate to control the valent state of the Rare Earth (RE) and to provide a high intensity of luminescence. It was demonstrated that the material has room for future improvement; however, this requires precise engineering of its composition—an experimental search of compositions or additives that will provide the maximum Eu2+/Eu3+ ratio to achieve a high scintillation light yield. The benefits of light inorganic materials are disclosed through the modeling of the linear density of nonequilibrium carriers along secondary particle tracks created in scintillators utilized for neutron detection. It is shown that oxide matrices have a larger linear density in comparison with halide crystalline compounds under alpha-particles and tritons, whereas light oxides can provide smaller numbers under protons. [ABSTRACT FROM AUTHOR]

This study aims to determine the optimum composition of the CeBr1−xIx compound to achieve the maximum light output. It is based on calculations of the band energy structure of crystals, specifically taking into account the characteristics of the mutual location of local and band 5d states of the Ce3+ ions. The band energy structures for CeBr2I and CeBrI2 crystals were calculated using the projector augmented wave method. The valence band was found to be formed by the hybridized states of 4p Br and 5p I. The 4f states of Ce3+ are located in the energy forbidden band gap. The conduction band is formed by the localized 5d1 states, which are created by the interaction between the 5d states of Ce3+ and the 4f0 hole of the cerium ion. The higher-lying delocalized 5d2 states of Ce3+ correspond to the energy levels of the 5d states of Ce3+ in the field of the halide Cl0 (Br0) hole. The relative location of 5d1 and 5d2 bands determines the intensity of 5d–4f luminescence. The bottom of the conduction band is formed by localized 5d1 states in the CeBr2I crystal. The local character of the bottom of the conduction band in the CeBr2I crystal favors the formation of self-trapped Frenkel excitons. Transitions between the 5d1 and 4f states are responsible for 5d–4f exciton luminescence. In the CeBrI2 crystal, the conduction band is formed by mixing the localized 5d1 and delocalized 5d2 states, which leads to quenching the 5d–4f luminescence and a decrease in the light output despite the decrease in the forbidden band gap. CsBr2I is the optimum composition of the system to achieve the maximum light output. [ABSTRACT FROM AUTHOR]

Eulytite-type Ba3RE(PO4)3 (RE = Y, La, and Lu) single crystals were synthesized by the floating zone method, and their scintillation properties were investigated. The powder X-ray diffraction measurement revealed that the single phase of Ba3RE(PO4)3 samples were successfully synthesized. The samples exhibited a luminescence peak due to self-trapped exciton at around 400 nm under vacuum ultraviolet and X-ray irradiation. The X-ray-induced scintillation decay time constants of the samples were several microseconds at room temperature. In the 241Am α-ray irradiated pulse height spectra, all the samples showed a clear full energy peak, and the absolute light yields of the Ba3Y(PO4)3, Ba3La(PO4)3, and Ba3Lu(PO4)3 single crystals were estimated to be 960, 1160, and 1220 ph/5.5 MeV-α, with a typical error of ±10%, respectively. The scintillation light yields of the Ba3RE(PO4)3 have been quantitatively clarified for the first time. [ABSTRACT FROM AUTHOR]

X-ray radiography and computed tomography have become well-established methods for investigation of internal structure of objects and for defectoscopy. Recently, the methods have even been used for in-situ analysis of materials under mechanical loading. Although the techniques would be very suitable for analysis during dynamic events, their application is constrained by typical achievable frame rates. Therefore, fast imaging is usually limited to facilities providing sufficient flux like particle accelerators. In this paper, we test imaging performance of a laboratory-based setup with a high-power X-ray tube, a scintillation panel, and an optical camera. Fast-rotating object and typical specimens for impact testing are irradiated with different power settings and quality of captured images is evaluated and analyzed. It is found out that the system can be successfully used for imaging at several hundred frames per second allowing for inspection of slow impact dynamics experiments. [ABSTRACT FROM AUTHOR]

The layered double perovskite microcrystals show excellent stability both under ambient condition and under X-ray irradiation, their luminescent properties and applications in X-ray imaging have been demonstrated. [Display omitted] Metal halide perovskites, as a new class of attractive and potential scintillators, are highly promising in X-ray imaging. However, their application is limited by the sensitivity to moisture and irradiation. To address this issue, we reported a 2D layered double perovskite material Cs 4 Cd 1-x Mn x Bi 2 Cl 12 that exhibits high stability both under ambient condition and under X-ray irradiation. Cs 4 Cd 1-x Mn x Bi 2 Cl 12 demonstrates superior scintillation performance, including excellent X-ray response linearity and a high light yield (∼34,450 photons/MeV). More importantly, the X-ray excited emission intensity maintains 92% and 94% of its original value after stored at ambient condition for over two years and after X-ray irradiation with a total dose of 11.4 Gy, respectively. By mixing with PDMS (polydimethylsiloxane), we have successfully produced a high-quality flexible film that can be bent freely while maintaining its excellent scintillation properties. The scintillating screen exhibits outstanding imaging ability with a spatial resolution of up to 16.7 line pairs per millimeter (lp/mm), also, the superiority of this scintillation screen in flexible X-ray imaging is demonstrated. These results indicate the huge potential of this high-stability double perovskite scintillator in X-ray imaging. [ABSTRACT FROM AUTHOR]

High-resolution neutron radiography provides novel and stirring opportunities to investigate the structures of light elements encased by heavy elements. For this study, a series of Gd2O2S:Tb, F particles were prepared using a high-temperature solid phase method and then used as a scintillation screen. Upon reaching 293 nm excitation, a bright green emission originated from the Tb3+ luminescence center. The level of F doping affected the fluorescence intensity. When the F doping level was 8 mol%, the fluorescence intensity was at its highest. The absolute quantum yield of the synthesized particles reached as high as 77.21%. Gd2O2S:Tb, F particles were applied to the scintillation screen, showing a resolution on the neutron radiograph as high as 12 μm. These results suggest that the highly efficient Gd2O2S:Tb, F particles are promising scintillators for the purposes of cold neutron radiography. [ABSTRACT FROM AUTHOR]

The search for color‐tunable, efficient, and robust scintillators plays a vital role in the development of modern X‐ray radiography. The radioluminescence tuning of copper iodide cluster scintillators in the entire visible region by bandgap engineering is herein reported. The bandgap engineering benefits from the fact that the conduction band minimum and valence band maximum of copper iodide cluster crystals are contributed by atomic orbitals from the inorganic core and organic ligand components, respectively. In addition to high scintillation performance, the as‐prepared crystalline copper iodide cluster solids exhibit remarkable resistance toward both moisture and X‐ray irradiation. These features allow copper iodide cluster scintillators to show particular attractiveness for low‐dose X‐ray radiography with a detection limit of 55 nGy s−1, a value ≈100 times lower than a standard dosage for X‐ray examinations. The results suggest that optimizing both inorganic core and organic ligand for the building blocks of metal halide cluster crystals may provide new opportunities for a new generation of high‐performance scintillation materials. [ABSTRACT FROM AUTHOR]

Undoped, 0.5, 1.0, and 2.0% Nd-doped Bi4Si3O12 (BSO) crystals were synthesized by the floating zone method. Regarding photoluminescence (PL) properties, all samples had emission peaks due to the 6p–6s transitions of Bi3+ ions. In addition, the Nd-doped samples had emission peaks due to the 4f–4f transitions of Nd3+ ions as well. The PL quantum yield of the 0.5, 1.0, and 2.0% Nd-doped samples in the near-infrared range were 67.9, 73.0, and 56.6%, respectively. Regarding X-ray-induced scintillation properties, all samples showed emission properties similar to PL. Afterglow levels at 20 ms after X-ray irradiation of the undoped, 0.5, 1.0, and 2.0% Nd-doped samples were 192.3, 205.9, 228.2, and 315.4 ppm, respectively. Dose rate response functions had good linearity from 0.006 to 60 Gy/h for the 1.0% Nd-doped BSO sample and from 0.03 to 60 Gy/h for the other samples. [ABSTRACT FROM AUTHOR]

The Nd-doped LaMgAl11O19 single crystals were synthesized by the floating zone method, and the photoluminescence and scintillation properties were evaluated. Under X-ray irradiation, several sharp emission peaks due to the 4f–4f transitions of Nd3+ were observed at 900, 1060, and 1340 nm in the near-infrared range, and the decay curves show the typical decay time for Nd3+. The samples show good afterglow properties comparable with practical X-ray scintillators. The 1% and 3% Nd-doped LaMgAl11O19 samples show a good linearity in the dynamic range from 6–60,000 mGy/h. [ABSTRACT FROM AUTHOR]

The review is devoted to the analysis of the compositional disordering potential of the crystal matrix of a scintillator to improve its scintillation parameters. Technological capabilities to complicate crystal matrices both in anionic and cationic sublattices of a variety of compounds are examined. The effects of the disorder at nano-level on the landscape at the bottom of the conduction band, which is adjacent to the band gap, have been discussed. The ways to control the composition of polycationic compounds when creating precursors, the role of disorder in the anionic sublattice in alkali halide compounds, a positive role of Gd based matrices on scintillation properties, and the control of the heterovalent state of the activator by creation of disorder in silicates have been considered as well. The benefits of introducing a 3D printing method, which is prospective for the engineering and production of scintillators at the nanoscale level, have been manifested. [ABSTRACT FROM AUTHOR]

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 Cs 5 Cu 3 Cl 6 I 2 scintillator is prepared by simple mechanical grinding. The mixed-halide Cs 5 Cu 3 Cl 6 I 2 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 Cs 5 Cu 3 Cl 6 I 2 can be increased to 88.4% from 20.4% by the efficient suppression of the anion vacancy defects. In addition, the Cs 5 Cu 3 Cl 6 I 2 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 nGy air /s. The X-ray imaging results based on the Cs 5 Cu 3 Cl 6 I 2 scintillator screen display a high spatial resolution of 9.0 line-pairs per millimeter (lp/mm). Furthermore, Cs 5 Cu 3 Cl 6 I 2 exhibits good radiation stability under a total dose of 113.58 Gy air. Overall, the Cs 5 Cu 3 Cl 6 I 2 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The ability of a scintillator to absorb and convert the high-energy X-ray photons to low-energy visible photons is crucial for the application of X-ray in medical tests, security checks and scientific research. However, traditional scintillation crystals are synthesized by complex preparation process with high cost, hindering the wide development in practical applications. Here, Tb3+ doped sodium silicate glass, which exhibits remarkable scintillation property and recoverability to X-ray irradiation, was successfully prepared by an exercisable melt-quenching method. The obtained scintillator shows intense radioluminescence, which is about 1.5 times higher than that of the reference of Bi 4 Ge 3 O 12. The damaged glass to X-ray irradiation can be returned to the original state after heat treatment again, indicating excellent recovery. Moreover, the scintillator displays wonderful thermal stability with the fluorescence intensity at 573 K still remaining 96% at room temperature. These results demonstrate that the obtained scintillating glass has potential application towards the real world. [ABSTRACT FROM AUTHOR]

Background: Radiodynamic therapy (RDT) holds the potential to overcome the shallow tissue penetration issue associated with conventional photodynamic therapy (PDT). To this end, complex and sometimes toxic scintillator–photosensitizer nanoconjugates are often used, posing barriers for large-scale manufacturing and regulatory approval. Methods: Herein, we report a streamlined RDT strategy based on CsI(Na)@MgO nanoparticles and 5-aminolevulinic acid (5-ALA). 5-ALA is a clinically approved photosensitizer, converted to protoporphyrin IX (PpIX) in cancer cells' mitochondria. CsI(Na)@MgO nanoparticles produce strong ~ 410 nm X-ray luminescence, which matches the Soret band of PpIX. We hypothesize that the CsI(Na)@MgO-and-5-ALA combination can mediate RDT wherein mitochondria-targeted PDT synergizes with DNA-targeted irradiation for efficient cancer cell killing. Because scintillator nanoparticles and photosensitizer are administered separately, the approach forgoes issues such as self-quenching or uncontrolled release of photosensitizers. Results: When tested in vitro with 4T1 cells, the CsI(Na)@MgO and 5-ALA combination elevated radiation-induced reactive oxygen species (ROS), enhancing damages to mitochondria, DNA, and lipids, eventually reducing cell proliferation and clonogenicity. When tested in vivo in 4T1 models, RDT with the CsI(Na)@MgO and 5-ALA combination significantly improved tumor suppression and animal survival relative to radiation therapy (RT) alone. After treatment, the scintillator nanoparticles, made of low-toxic alkali and halide elements, were efficiently excreted, causing no detectable harm to the hosts. Conclusions: Our studies show that separately administering CsI(Na)@MgO nanoparticles and 5-ALA represents a safe and streamlined RDT approach with potential in clinical translation. [ABSTRACT FROM AUTHOR]

This study provided the first in-depth investigation of the effects of large dopant incompatibility (Pr3+ and La3+ ions) on the small host lattice element (Lu3+) in Lu 3 Al 5 O 12 (LuAG) single crystal. The growth of such complex crystals from the melt presented many challenges. By engineering the ionic radius ratio of RE- and M-site cations, a single-crystal phase stabilized by configurational entropy was achieved. This investigation elucidated the crystallization behavior of configurationally disordered rare-earth aluminum garnet oxide (Lu 1−x−y Pr x La y) 3 Al 5 O 12 from the melt and characterized its functional properties, including microstructural, optical, photoluminescence, and scintillation properties, between 5 and 300 K. Relaxation of the imposed strain energy led to local perturbations and destabilization of the garnet structure. Multielemental EDS mapping, micro-Raman spectroscopy, and thermoluminescence revealed the mechanism by which atomic size mismatch drove a smooth transition from the garnet to the perovskite phase in high entropy garnets. The optical, photoluminescence, and scintillation measurements provided fundamental insights into property changes driven by incompatibility doping. Standard and modified Judd-Ofelt theory analysis of absorption spectra determined the phenomenological Judd-Ofelt parameters Ω λ and radiative lifetimes. Atomic size mismatch engineering offers a promising approach to overcoming the limitations of conventional eutectic synthesis methods. • Perovskite inclusions, driven by atomic size mismatch, extend from rim to core. • Controlled incompatible La3+,Pr3+ codoping in LuAG modify functional properties. • Scintillation light yield improved up to 30% in La3+ codoped LuAG:Pr crystals. • (La,Pr)AlO 3 perovskite forms due to size mismatch of La3+ and Pr3+ with Lu3+. • Lattice disorder affects the intensity ratio of Pr³⁺ 5d→4 f and 4 f→4 f emissions. [ABSTRACT FROM AUTHOR]

A special group of luminescence materials are scintillators for thermal neutron detection. Due to the properties of neutrons (contrary to e.g. electrons or gamma photons), a different approach has to be utilized—the high content of atoms with the sufficient absorption cross‐section toward neutrons and lower material density are needed. This work pursues a basic study of LiSrBO3 and LiSr4(BO3)3 doped with cerium or europium—materials promising as thermal neutron scintillators. These borates exhibit promising properties such as the high content of lithium and boron, suitable density, and proper environment for luminescent ions. Radioluminescence of these ceramic borates doped with cerium and europium was examined and promising samples were further characterized by photoluminescence spectroscopy and radioluminescence and photoluminescence kinetics measurement. The radioluminescence study of these borates is published for the first time. Cerium‐doped borates, in particular, exhibit a very promising response to an X‐ray excitation. [ABSTRACT FROM AUTHOR]

As one of the commonly used scintillating materials, single crystals inhibit their further practical applications considering the high cost, limited volume, and time-wasting preparation technique. By the compelling requirement for radiative detection in a variety of fields, numerous novel scintillators have been developed. Here, a novel efficient and transparent Eu3+-doped boroaluminate glass was successfully fabricated by melt-quenching technique. The optical responses to ultraviolet–visible (UV) and X-ray are both significantly enhanced by heavily doping Eu3+ into the glass host. The optimal doping concentration of Eu3+ is 8 mol%. Moreover, the internal quantum yield (IQY) was evaluated to 53.2% with high transparency (83% @ 600 nm). More notably, the best specimen has 18.4% X-ray excited luminescence (XEL) integrated intensity of that of the commercial Bi 4 Ge 3 O 12 single crystal scintillator. According to our findings, heavily doped boroaluminate glass could be one of the alternative scintillating materials for slow process detection. [ABSTRACT FROM AUTHOR]

The low-energy ultraviolet or visible photons can be produced by the interaction between the scintillator materials and ionizing radiation. For this reason, scintillator materials are widely used as radiation detectors, which are prevalently utilized in different applications such as nuclear medicine imaging, homeland security, high-energy physics, oil drilling explorations, etc. Herein, a high-atomic-number (Z) zirconium-based metal-organic framework nanoflower material CJLU-1 (Zr 6 (μ 3 -O) 4 (μ 3 -OH) 4 (OH) 6 (TCA) 2 (H 2 O) 6) (H 3 TCA = tri-carboxylic acids 4,4′,4″-nitrilotribenzoic acid) was synthesized and can effectively convert X-ray into visible light. CJLU-1 is composed of secondary structural unit hexagonal Zr metal cluster and connected by TCA ligands. The photo luminescence spectra (PL) emission peak and excitation peak of CJLU-1 are at 470 nm and 395 nm respectively. CJLU-1 exhibited radioluminescence (RL) peak with a maximum at 480 nm under steady-state excitation with X-rays. Moreover, by accommodating different guest molecules such as xylene and RhB in the same MOF material, intensity-tunable X-ray scintillation can be facilely achieved, providing a new class of scintillating materials with luminescence intensity tunability. The high-Z hexagonal Zr clusters, which are arranged in an orderly fashion, absorb and interact with the ionizing radiation and sensitize the adjacent organic ligands TCA to produce efficient RL. This work contributes to the development of high-Z zirconium-based MOFs and RL intensity-tunable scintillation materials towards future practical nuclear sensing applications. A high-atomic-number (Z) zirconium-based metal-organic framework nanoflower material CJLU-1 was synthesized and can effectively convert X-ray into visible light. [Display omitted] • A zirconium-based MOF was constructed and realized tunable radioluminescence upon accommodation of guest molecules. [ABSTRACT FROM AUTHOR]

All‐inorganic perovskite quantum dots (QDs) CsPbX3 (X = Cl, Br, and I) have recently emerged as a new promising class of X‐ray scintillators. However, the instability of perovskite QDs and the strong optical scattering of the thick opaque QD scintillator film imped it to realize high‐quality and robust X‐ray image. Herein, the europium (Eu) doped CsPbBr3 QDs are in situ grown inside transparent amorphous matrix to form glass‐ceramic (GC) scintillator with glass phase serving as both matrix and encapsulation for the perovskite QD scintillators. The small amount of Eu dopant optimizes the crystallization of CsPbBr3 QDs and makes their distribution more uniform in the glass matrix, which can significantly reduce the light scattering and also enhance the photoluminescence emission of CsPbBr3 QDs. As a result, a remarkably high spatial resolution of 15.0 lp mm−1 is realized thanks to the reduced light scattering, which is so far a record resolution for perovskite scintillator based X‐ray imaging, and the scintillation stability is also significantly improved compared to the bare perovskite QD scintillators. Those results provide an effective platform particularly for the emerging perovskite nanocrystal scintillators to reduce light scattering and improve radiation hardness. [ABSTRACT FROM AUTHOR]

Glass compounds have gained attention as scintillating materials owing to their large production possibility, easy shaping and flexible glass composition, and various glasses such as silicate, germanate and borate glasses have been considered for scintillator applications. Herein, Eu 2 O 3 -doped bismuth gallate glasses having a composition of 5K 2 O–70Bi 2 O 3 –25Ga 2 O 3 were synthesized for the development of new glass scintillators by the melt-quenching method. After the fabrication of the undoped and Eu 2 O 3 -doped bismuth gallate glasses, their optical and scintillation characteristics were evaluated. The Eu 2 O 3 -doped bismuth gallate glasses showed photoluminescence (PL) and scintillation with sharp peaks centered at approximately 596 and 612 nm due to the electronic 4f → 4f transitions of Eu3+. The PL and scintillation spectra revealed that the concentration dependence of the PL quantum efficiency for the Eu 2 O 3 -doped bismuth gallate glasses was well correlated with that of the scintillation intensity. The decay time constants of the 0.5% and 1.0% Eu 2 O 3 -doped bismuth gallate glasses under visible light and X-ray irradiation were approximately 0.55 ms and 0.15 ms, respectively. In addition, the undoped and Eu 2 O 3 -doped bismuth gallate glasses exhibited afterglow levels of 330–660 ppm, and their moderate levels were found to be almost comparable to the afterglow level of Tl-doped CsI. [ABSTRACT FROM AUTHOR]

The NDeGRA project is researching the application of novel technologies in the development of position-sensitive detectors for gamma ray astronomy and medical imaging. The project's approach to simulation and some preliminary results on the upper limit of efficiency of a Compton camera design based on monolithic scintillator crystals are discussed. [ABSTRACT FROM AUTHOR]

This study concerns cerium and boron doped Lu 3 Al 4 Sc 1 O 12 and Gd 3 Al 3 Sc 2 O 12 garnet µ-crystalline powders, which were synthesized for the first time. Rare earth ion, particularly Ce3+ activated garnets, due to their high density and efficient Ce3+ luminescence upon blue, UV, or x-ray excitation, can be used as scintillators that convert high-energy radiation into visible light. The incorporation of B3+ and Sc3+ ions into the garnet matrix corresponds to the improvement of the scintillating properties. Boron in these compounds could act like a flux and thus modulate particle morphology, while scandium solely changes the physical and luminescent properties of these garnets. From the measured radioluminescence emission spectra, it could be concluded that boron doping results in a higher emission intensity when the compounds are excited by high-energy radiation. The most striking effect is that the decay time is reduced, and the quantum efficiency of the compounds increases. After improving the kinetic properties of these compounds, it is possible to discuss a wider application of the synthesized materials. In addition to the aforementioned properties, room temperature as well as temperature dependent photoluminescence emission, excitation, and decay times at different temperatures were taken for all samples. The elemental composition of the samples was determined by using the ICP-OES technique. The crystal structure was analyzed by means of powder XRD. Particle morphology and size distribution were also investigated. The main idea of this research is to synthesize new and adjusted garnet type compounds that show better luminescent properties, which are required for scintillator materials. • Pure B3+ and Sc3+ co-doped LuAG:Ce and GdAG:Ce were synthesized by Sol-Gel method. • Reflectance spectra indicated about good quality of synthesized compounds. • Boron doping led to an increase in radio/photo luminescence intensities. • A reduction in decay times was caused by B3+ and Sc3+ co-doping. • Co-doping with B3+ led to an increase in quantum efficiency. [ABSTRACT FROM AUTHOR]

Gd3+-sensitized rare earth fluoride scintillators for high-resolution flexible X-ray imaging. [Display omitted] • Dumbbell-shaped YF 3 :Gd3+/Tb3+ NPs were prepared through ultra-fast chemical precipitation. • YF 3 :Gd3+/Tb3+ NPs show superb chemical stability and X-ray radioluminescence. • YF 3 :Gd3+/Tb3+@PDMS films have enough capacity 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, YF 3 :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 YF 3 :30%Gd3+/10%Tb3+ MPs exhibited fine environmental stability and superb X-ray RL, which was stronger than that of commercial scintillators Bi 4 Ge 3 O 12 (BGO) and even comparable to that of CsI:TI single crystal. Highly flexible transparent YF 3 :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 YF 3 :Gd3+/Tb3+/PDMS scintillation films endow them with the potential application in high-resolution industrial nondestructive inspection and biological imaging. [ABSTRACT FROM AUTHOR]

In this study, we fabricated Cs 3 ScCl 6 crystals doped with different concentrations of Ce and investigated their luminescence properties. In both the photoluminescence (PL) and scintillation spectra, emission bands attributable to Ce3+ 5d–4f transition were observed. The PL temporal profiles revealed decay time constants of ~35 ns, which are typical values for Ce3+ 5d–4f transition. In the scintillation temporal profiles, two decay components were observed. The fast and slow components could be attributed to Ce3+ 5d–4f luminescence and self-trapped excitons (STEs) or a slow energy transfer from STEs to Ce3+, respectively. The maximum light yield was 9200 photons/MeV for a Ce concentration of 0.5 mol%. [ABSTRACT FROM AUTHOR]

The urgent demand for radiation detection in diverse applications boosts extensive investigations on scintillators. However, the current scintillating materials are mostly limited to mono-crystals with high cost, restricted volume and time-consuming fabrication techniques. Here, we report an efficient and transparent Tb3+-doped Sr 2 GdF 7 glass ceramic (GC) prepared via simple melt-quenching method, and its optical response to X-ray. By incorporating Tb3+ into crystallized Sr 2 GdF 7 inside a typical aluminosilicate glasses, highly enhanced green emission was observed under UV and X-ray excitation. After thermal treatment, the internal and external photo-luminescence quantum yields can be as high as 59.1 and 26.4%, respectively, with the high transparency (65%@550 nm) preserved. More interestingly, this composite material, combining the advantages of oxide glasses and fluoride crystals, presents strong X-ray excited luminescence (XEL). Its XEL intensity is 194% of that of commercial BGO scintillator. Evidenced by detailed optical and structural properties, it can be concluded that rare earth ions activated bulk oxyfluoride glass ceramics with unique merits, such as low-cost, high efficiency and intense radio-luminescence, could be alternative scintillating materials for high energy ray detection. [ABSTRACT FROM AUTHOR]

A novel process has been developed for the preparation of Bi4Ge3O12 (BGO) by self-propagating high-temperature synthesis. In this method, microwave radiation is used for the first time to heat organic fuel (urea), which allows its decomposition to be uniformly activated throughout the reaction mixture. The key synthesis parameters are the pH of the medium, the volume of the liquid phase in the system, and the way in which the starting mixture is homogenized. Varying these parameters has made it possible to reduce the synthesis time to 3 min. We have obtained BGO samples consisting of quasi-spherical particles, potentially attractive for the fabrication of scintillating ceramics. In addition, we have synthesized powders that have an order of magnitude better kinetic scintillation characteristics in comparison with single-crystal BGO and are thus interesting for designing scintillating materials for highly sensitive detectors. [ABSTRACT FROM AUTHOR]

The rising requirement for radiation detection materials for practical applications has inspired to burgeoning investigation of scintillator materials. High performance X-ray detection require high spatial resolution and long-term stability, particularly for targeted objects at extreme conditions. Here, the CaF 2 :Eu2+ glass ceramic (GC), in which the CaF 2 :Eu2+ nanoparticles are wrapped by the glassy matrix, is successfully obtained the melting method. The as-obtained CaF 2 :Eu2+ GC manifests bright blue radioluminescence (RL) emission peaked at 470 nm thanks to the effective 5d-4f transition of Eu2+ ions. In addition, the as-obtained CaF 2 :Eu2+ GC presents high transmittance of 84.2% and visible light, contributing an excellent spatial resolution of 15 lp/mm at room temperature. Importantly, the as-obtained CaF 2 :Eu2+ GC exhibits high robustness at water conditions and high thermal stability with X-ray resolution of 12.1 lp/mm at 473 K. Our work demonstrates that CaF 2 :Eu2+ GC scintillators provide an excellent visualization tool for high-resolution scintillators X-ray images in harsh conditions. • The reduction efficiency of Eu2+ is significantly improved by mixing the reducing agent with glass ceramic raw and sintering. • The CaF 2 :Eu2+ glass ceramic is successfully obtained by melt-quenching method. • Multiple characterization prove that Eu2+, the luminescent center of glass ceramic, is greatly reduced in glass ceramic. • The strategy significantly reduces the light scattering and enhance the stability of the emitting centers. • The CaF 2 :Eu2+ glass ceramic for high resolution X-ray detection in harsh conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Scintillator screen with micro/nano particles embedded into delignified wood. • Vertical column structured material suppressing the light lateral spreading. • Linear relationship between light yield and X-ray dose rate. • High spatial resolution X-ray imaging achieved. Nanocrystalline scintillators with low-cost, fast response, and high light yield are widely used for X-ray imaging. However, they fail in high-energy X-ray imaging because of the fundamental limitations due to lateral radiation spreading in thicker device-compatible active layers. This issue is resolved by using the novel nanocomposite containing CsPbBr 3 scintillation single-microcrystalites embedded into transparent, natural wood-derived light-guiding fibrous structures. The CsPbBr 3 crystals convert X-ray to visible photons with a high photoluminescence quantum efficiency (76 %), and an average fast photoluminescence decay time of 25.9 ns. The delignified wood-derived fiber-like lumina effectively guide light, while suppressing the lateral spreading of scintillation photons. This unique porous nanocomposite material offers an excellent X-ray detection performance, and linear response in a wide parameter range. The developed scintillator screen achieves well-resolved, high-contrast X-ray imaging, featuring a very high spatial resolution of 11.9 lp/mm at a modulation transfer function of 0.2, thus exceeding the benchmark industry standards and offering a new advanced materials platform for radiation detection and dosimetry applications. [ABSTRACT FROM AUTHOR]

Abstract Crystal growth and luminescence properties of the intrinsic Tl 2 ZrCl 6 scintillation crystal are presented. The proposed crystal is a promising candidate for γ-ray detection owing to its high light yield, good energy resolution, and high effective atomic number (Z = 69). It has a cubic structure, which is desirable for a large-size-crystal growth. In this study, the crystal is grown from its melt using the Bridgman technique. The emission peak under X-ray excitation is found at 460 nm, with a primary decay time of 2.7 μs. The light yield and energy resolution are estimated to be 47,000 photons/MeV and 4.3% (full-width-at-half-maximum), respectively, obtained from the pulse-height spectra under a 137Cs 662-keV γ-ray excitation. Highlights • Tl 2 ZrCl 6 crystal has been grown by Bridgman technique for first time. • The grown crystal was characterized under X- and γ-rays excitation. • High-Z material with high light yield and good energy resolution were obtained. • It has the potential to be X- and γ-ray detectors for various applications. [ABSTRACT FROM AUTHOR]

Ce 3+ ions doped Li 6 Gd(BO 3 ) 3 crystal is a promising low density scintillators for thermal neutron detection. The Czochralski growth of LGBO crystal have been optimized and single crystals with larger sizes have been grown with different techniques. LGBO crystal bowl with diameter larger than 43 mm were grown with Iridium ring increasing the radial temperature gradient and after-heater decreasing the upside axial temperature gradient. Meanwhile LGBO crystal disk with diameter larger than 50 mm were also grown with very low pulling rate and radial temperature gradient. To investigate the overall performance of LGBO series of crystal, Li 6 Y(BO 3 ) 3 crystal and its mixed crystals with Li 6 Gd(BO 3 ) 3 have also been grown using Czochralski method. The thermal expansion coefficients of LGBO and LYBO crystals were investigated using the high temperature XRD patterns, respectively. The big difference between melting and freezing point meant that the metastable phases have formed during cooling cycle for the Ostwald's rule. The optical transmission spectra, x-ray stimulated, photoluminescence and thermal stimulated luminescence spectra were also investigated, respectively. And Li 6 Gd 0.1 Y 0.9 (BO 3 ) 3 :Ce crystal may be the most promising crystals for thermal neutron detection for the best light output by α particles and the highest light output ratio α/γof 0.16. [ABSTRACT FROM AUTHOR]

A transparent gadolinium-rich oxyhalide glass scintillator was developed for gamma ray spectroscopy with an energy resolution of 14.0% at 662 keV. To the best of our knowledge, this is the highest energy resolution reported for a glass-based scintillator. The high gadolinium content facilitated a scintillator density of 4.4 g/cm3. The high fluorine and bromine incorporation is advantageous for better uniformity and a good light output of ~3200 Ph/MeV. The peak emission at 431 nm with a FWHM of 90 nm, resulting from the fast Ce3+ transitions, yielded pulse-height spectra with distinctive peaks from 122 keV to 1.33 keV for gamma radiation from different nuclides. [ABSTRACT FROM AUTHOR]

Flexible and stretchable materials are increasingly being investigated for future technological platforms, polymer based materials being the most suitable candidates for those emerging technologies. This work reports on polymer based scintillator composites based on the thermoplastic elastomer Styrene-Ethylene/Butadiene-Styrene (SEBS) and Gd 2 O 3 :Eu 3+ scintillator nanoparticles, to form a polymer-based flexible and stretchable material for X-ray indirect detectors. Further, visible light yield under X-ray irradiation was improved by the inclusion of 2,5 dipheniloxazol (PPO) and (1,4-bis (2-(5-phenioxazolil))-benzol (POPOP) within the polymer matrix. Together with high levels of stretchability, with deformations up to 100%, the films exhibit suitable performance with low mechanical hysteresis (less than 1.5 MJ/m 3 for cycles up to 100% of strain) and reproducibly such as a scintillator material for the conversion of X-ray radiation into visible radiation. The decrease of just ∼13% of the X-ray radiation into visible light upon stretching up to 100% is attributed to a reduction of the effective filler concentration and proves the suitability of the developed materials for large area and stretchable X-ray radiation detectors. [ABSTRACT FROM AUTHOR]

We have developed MgF 2 :Eu transparent ceramics using spark plasma sintering (SPS) and investigated the photoluminescence (PL), scintillation and dosimeter properties. Under X-ray irradiation, intense peaks appeared at 390 and 430 nm in all the samples. They were attributed to the 5d-4f transitions of Eu 2+ and some kinds of defect centers generated by doping with Eu 2+ , respectively. The scintillation decay times of the emissions at 430 nm for the 0.01, 0.02, 0.05 and 0.1% Eu-doped samples were 21.1, 20.9, 18.6 and 23.4 ms, respectively. Furthermore, all the samples showed a thermally stimulated luminescence (TSL) over 120–250 °C. The TSL response was very sensitive to irradiation dose and showed a good linearity from 0.01 mGy to 100 mGy. The TSL emission measured at 170 °C was only by the luminescence band at 430 nm due to defect centers. [ABSTRACT FROM AUTHOR]

We have prepared MgF 2 transparent ceramics by spark plasma sintering (SPS) and investigated the scintillation and dosimeter properties compared with those of a single crystal. Under X-ray irradiation, a transparent ceramic showed scintillation with a broad feature over 300–600 nm with decay times of 310 and 1940 μs while the single crystal did not show such emission. It was found that MgF 2 show radio-photoluminescence (RPL), which is a generation of new luminescence center by ionizing radiation. The RPL was only observed in the transparent ceramic samples, which appeared as two emission bands peaking around 415 and 700 nm under 340±40 nm excitation. During the PL reading, the emission band at 415 nm effectively increased over 50 s. This result suggested that the RPL in MgF 2 shows a build-up phenomenon. From PL emission/excitation characteristics and decay time, it was suggested that the RPL peak around 415 nm was due to M(C 2h ) center. [ABSTRACT FROM AUTHOR]

We have developed CaF 2 transparent ceramics doped with Eu 2+ (CaF 2 :Eu) by using spark plasma sintering (SPS), and investigated the scintillation, dosimeter and photoluminescence (PL) properties. Under X-ray irradiation, all the samples showed emission due to self-trapped excitons (STE) and 5d-4f transition of Eu 2+ at 300 and 430 nm, respectively. In addition, weak emission due to the 4f-4f transitions of Eu 3+ at 570, 590, 615 and 625 nm were also present in all the samples. Under 137 Cs irradiation, the light yields of the 0.01, 0.02, 0.05 and 0.1 Eu-doped samples were estimated to be 16,400, 15,400, 17,700 and 14,300 photons/MeV, respectively. Thermally stimulated luminescence (TSL) glow curves of all the samples exhibited glow peaks at 100 and 180 °C, and these intensities increased linearity as a function of X-ray dose from 0.1 to 1000 mGy. Furthermore, the CaF 2 :Eu showed not only TSL but also optically stimulated luminescence (OSL). [ABSTRACT FROM AUTHOR]

The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits). [ABSTRACT FROM AUTHOR]

We have synthesized a MgO transparent ceramic by spark plasma sintering (SPS) and studied the dosimeter properties for X-ray detections, in comparison with the single crystal form. Further, we have characterized the optical and scintillation properties. Despite the same material compositions, the photoluminescence (PL) of the ceramic sample showed dominantly around 450 nm whereas the single crystal sample had a dominant emission in the NIR range. The PL lifetime of 450 nm were measured to be ~10 and ~50 ns which were typical for emissions by F + center in MgO. The scintillation spectra were similar to those observed in PL, but the lifetime was much longer on the micro-second scale. The TSL glow curves of MgO ceramic showed a main peak around 140 °C. The TSL spectrum at 140 °C had a broad emission band in the 300–400 range and around 600 and 750 nm, which approximately coincide with the scintillation spectra. The TSL response was confirmed to be linear to the irradiation dose for both samples over the dose range from 0.1 to 1000 mGy. [ABSTRACT FROM AUTHOR]

The polystyrene doped with 2,5-diphenyloxazole as a primary fluor and 2-(4-styrylphenyl)benzoxazole as a wavelength shifter prepared as a plastic scintillator was investigated using positronium probe in wide range of temperatures from 123 to 423 K. Three structural transitions at 260, 283, and 370 K were found in the material. In the o-Ps intensity dependence on temperature, the significant hysteresis is observed. Heated to 370 K, the material exhibits the o-Ps intensity variations in time. [ABSTRACT FROM AUTHOR]

This work reports on the synthesis of Eu 3+ -doped Gd 2 O 3 using PEG as an organic molecular precursor with 1, 3, 5, 7 e 10 mol% of Eu 3+ . TGA and DTA analysis of the precursors obtained shows that the final materials are obtained at thermal treatment above 700 °C. Based on this information all materials were obtained after heat treatment at 900, 1000 and 1100 °C during 4 h in an oven under air atmosphere. XRD analysis showed that the materials obtained after heat-treatment presents a cubic crystalline structure assigned to the Gd 2 O 3 . Crystallite size and microstrain were evaluated using the Scherrer's equation and Williansom-Hall method, respectively, as a function of heat-treated temperature and Eu 3+ concentration. Raman spectroscopy also showed the formation of the Gd 2 O 3 phase, however, the absence of bands around 117 cm −1 in the spectra with higher Eu 3+ concentration indicates that the insertion of this one in the host matrix promotes the breakdown of some chemical bonds of the matrix. Intense photoluminescence emission in the visible region with maximum localized around 611 nm under excitation at 255 nm with xenon lamp and with X-ray source were observed. The emissions observed were attributed to the intraconfigurational f–f transitions of Eu 3+ . The lifetime values of the 5 D 0 excited state were between 2.84 and 2.89 ms, indicating the location of Eu 3+ in crystalline systems. This result demonstrates the potential application of the materials in systems for absorption in the ultraviolet region, solar cells, devices generated images and scintillation systems. [ABSTRACT FROM AUTHOR]

We used single-crystal X-ray diffraction data to determine crystal structure of CsCe 2 Cl 7 . It crystallizes in a P 112 1 / b space group with a =19.352(1) Å, b =19.352(1) Å, c =14.838(1) Å, γ =119.87(2)°, and V =4818.6(5) Å 3 . Differential scanning calorimetry measurements combined with the structural evolution of CsCe 2 Cl 7 via X-ray diffractometry over a temperature range from room temperature to the melting point indicates no obvious intermediate solid–solid phase transitions. The anisotropy in the average linear coefficient of thermal expansion of the a axis (21.3×10 –6 /°C) with respect to the b and c axes (27.0×10 –6 /°C) was determined through lattice parameter refinement of the temperature dependent diffraction patterns. These findings suggest that the reported cracking behavior during melt growth of CsCe 2 Cl 7 bulk crystals using conventional Bridgman and Czochralski techniques may be largely attributed to the anisotropy in thermal expansion. [ABSTRACT FROM AUTHOR]

The photoluminescence spectra of CuI crystals using synchrotron radiation as an excitation light source were obtained at 60 K. The emission peaks at 405, 415, 420 and 443 nm were observed. The possible origins of these peaks were discussed by the temperature dependence of luminescence spectra for CuI material. Meanwhile, the photoluminescence spectra of CuI powder with different excitation intensity were measured and the ultrafast luminescence component of CuI crystals was warranted to be attributed to the recombination of donor acceptor pair. Furthermore, the excitation process was studied by measuring the photoluminescence excitation spectra of CuI crystals and powder. [ABSTRACT FROM AUTHOR]

With the advancement of ultra-fast and high-energy pulsed laser output, lasers have caused serious harm to precision instruments and human eyes. Therefore, the development of optical limiting materials with a fast response, low optical limiting threshold, and high damage threshold are important. In this work, for the first time, it is reported that phosphors Gd2O2S:Tb3+(GOS) displays exceptional functionality in laser protection. GOS with sizes of 11 μm, 1 μm, and 0.45 μm are prepared. Based on the optical limiting and Z-scan technology systems under 532 nm and 1064 nm nanosecond laser excitation, the nonlinear optical properties of GOS are investigated. It is found that GOS exhibits outstanding optical limiting properties. In addition, the optical limiting response of GOS is size-dependent. Concerning the largest particle size, GOS has the best nonlinear optical response, while the precursor shows no nonlinear optical performance. Meanwhile, GOS doped gel glass also displays excellent optical limiting properties with high transmittance, which preliminarily validates the application of GOS and other scintillators in nonlinear optics and encourages more research to better realize the potential of GOS. [ABSTRACT FROM AUTHOR]

Highlights: [•] Alkali rare-earth double phosphates are candidate scintillators for γ-rays detection. [•] X-ray and neutron diffraction were used to study the structure of K3Lu(PO4)2 as a function of temperature. [•] Two low temperature phases transitions occur at 230K and 130K, both with monoclinic symmetry. [•] This is an unusual example of an isosymmetric phase transition with a coordination change, driven by temperature. [ABSTRACT FROM AUTHOR]