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High-performance and low-cost metal halide perovskite scintillator materials have important applications in X-ray detection and imaging. However, large-sized perovskite scintillator panel with high transmittance, low toxicity and long-term stability is still lacking. Herein, Eu2+ doped cesium alkaline earth chloride nanocrystals (Eu2+: CsCaCl 3 , Eu2+: CsSrCl 3 , and Eu2+: Cs 2 BaCl 4 NCs) embedded in glasses through conventional melt-quenching and subsequent heat-treatment were developed. These NCs doped glasses exhibited highly efficient and narrowband photoluminescence in blue region. Benefitting from the large X-ray absorption coefficient and high photoluminescence quantum yied, these Eu2+: CsCaCl 3 NCs doped glass scintillator shows light yield of ∼9300 photons/MeV, detection limit of ∼213.8 μGy/s, and spatial resolution of 30.0 lp/mm. These results demonstrated that glasses containing Eu2+ doped cesium alkaline earth chloride nanocrystals are promising for X-ray detection and imaging. [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]

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 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]

Lead halide perovskites with excellent optoelectronic properties have attracted extensive attention and made amazing progress for X-ray detectors and imaging. However, lead is highly toxic to humans, animals and ecosystems, posing a great safety concern to its commercial application. It has become an urgent need to develop stable and environment-friendly lead-free alternatives. In this review, we summarize recent progress in lead-free halide perovskites (LFHPs) and derivatives toward X-ray detectors and imaging. First, we introduce the working principle of X-ray detectors and the key figure of merit in direct and indirect detection processes. In addition, we summarize state-of-the-art lead-free halide perovskites preparation methods. Furthermore, we comprehensively discuss the structural dimensions, optoelectronic properties of lead-free halide perovskites and their recent advances in X-ray detection and imaging. Meanwhile, the stabilities of LFHPs-based X-ray detectors are discussed. Finally, we outline several main issues of state-of-the-art LFHPs-based X-ray detectors and provide prospects to overcome these limitations. [ABSTRACT FROM AUTHOR]

Abstract We examined the use of cerium-doped gadolinium aluminum gallium garnet (GAGG:Ce) as a material for scintillation screens in synchrotron X-ray radiography (SXR). Highlighted for gamma-ray detection, GAGG:Ce is also an attractive material for SXR because of its high X-ray stopping power and the high light yield at around 530 nm. A thin and transparent screen prepared from our grown ingot of GAGG:Ce was compared with commonly used scintillators of CdWO 4 and YAG:Ce in terms of image quality under monochromatic X-ray illumination. Micron spatial resolutions were achieved with comparable image quality, suggesting that a single crystal of GAGG:Ce is competent scintillation material for SXR. Highlights • Micron-spatial resolutions are achievable using GAGG:Ce single crystal scintillation. • Visibility was compared with other commonly used scintillator screens. • GAGG:Ce was also competent in synchrotron X-ray micro computed tomography. [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]

The Eu 3+ -doped CaO-Gd 2 O 3 -SiO 2 -B 2 O 3 glasses were prepared to study photoluminescence, lasing potential and scintillation properties. Glasses absorb photons in ultraviolet, visible light and near infrared regions and are assigned to the energy transitions of Gd 3+ and Eu 3+ . Ultraviolet with 275 nm can generate the strong red emission with 614 nm via energy transfer form Gd 3+ to Eu 3+ . X-ray scintillation study exhibits strong emission pattern due to Gd-Eu energy transfer. The optimum concentrations of Eu 3+ ion in this glass is 0.30 mol% as it results maximum emission intensity. The fluorescence lifetime of the 5 D 0 level decreases from 1.763 to 1.726 ms when concentration increased from 0.05 to 0.40 mol%. From Judd-Ofelt analysis, this glass exhibit high potential for using as laser medium for red laser device with high lasing power and energy extraction ratio. Moreover, this glass performs the integral scintillation efficiency as 13% compared with BGO. [ABSTRACT FROM AUTHOR]

We developed a new scintillation timing detector using a proportional-mode silicon avalanche photodiode (Si-APD) for synchrotron radiation nuclear resonant scattering. We report on the nuclear forward scattering measurement on 61 Ni with a prototype detector using a lead-loaded plastic scintillator (EJ-256, 3 mm in diameter and 2 mm in thickness), mounted on a proportional-mode Si-APD. Using synchrotron X-rays of 67.41 keV, we successfully measured the time spectra of nuclear forward scattering on 61 Ni enriched metal foil and 61 Ni 86 V 14 alloy. The prototype detector confirmed the expected dynamical beat structure with a time resolution of 0.53 ns (FWHM). [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]

Here, we successfully prepared Tb3+-activated borogermanate glass by the traditional melt-quenching method. The optical and scintillating properties were investigated by using photoluminescence, transmission spectra, luminescence decay curves and X-ray excited luminescence. High content of Gd 2 O 3 was added into borogermanate glass to improve the density of glass (about 5.52 g/cm3), and thus to enhance the radiation stopping power. Al powder was introduced into the composition as reducing agent. Due to incorporation of Al powder, the internal quantum efficiency of glass increases from 18.8% to 56.3%. Meanwhile, the integrated intensity of X-ray excited luminescence of glass promotes from 29.8% to 46.6% compared to Bi 4 Ge 3 O 12 scintillating crystal. All above results declare that Al powder as reducing agent can strengthen the optical and scintillating properties of Tb3+-activated borogermanate glass. • The density of borogermanate glass with high content of Gd 2 O 3 is 5.52 g/cm3. • The quantum efficiency increases from 18.8% to 56.3% after addition of Al powder. • The XEL intensity promotes from 29.8% to 46.6% due to addition of Al powder. [ABSTRACT FROM AUTHOR]

To obtain both a high count rate of >10 7 s −1 and a detection efficiency sufficient for high-energy X-rays of >30 keV, we propose a scintillation timing detector using a proportional-mode silicon avalanche photodiode (Si-APD) for synchrotron radiation nuclear resonant scattering. We here present results obtained with a prototype detector using a lead-loaded plastic scintillator (EJ-256) mounted on a proportional-mode Si-APD (active area size: 3 mm in diameter). The detector was operated at ‒35 °C for a better signal-to-noise ratio. Using synchrotron X-rays of 67.41 keV, which is the same energy as the first excited level of 61 Ni, we successfully measured pulse-height and time spectra of the scintillation light. A good time resolution of 0.50±0.06 ns (full width at half-maximum) was obtained for 67.41 keV X-rays with a scintillator 3 mm in diameter and 2 mm thick. [ABSTRACT FROM AUTHOR]

A new 1D coordination polymer [Pb(adba)(DMF)] n exhibits the competitive sensitivity, detection limit and radiation stability responsive to X-ray and could serve as a promising scintillating material candidate for X-ray detection in highly irradiating conditions. [Display omitted] • A new X-ray responsive 1D coordination polymer [Pb(adba)(DMF)] n (named as Pb-adba , H 2 adba = 4,4′-(9,10-anthracenediyl)dibenzoic acid, DMF = N , N -dimethylformamide) was constructed with Pb(II) salt and H 2 adba by a mild solvothermal process. • Pb-adba exhibits the competitive sensitivity and detection limit toward X-ray than classical scintillators PbWO 4 (PWO), anthracene and some reported SMOFs. • Pb-adba possess favorable radiation stability at the dose rate of 42.29 mGy/s for 3 h (equivalent to the cumulative dose of 456 Gy). The strong X-ray attenuation and beneficial optoelectronic properties of lead(II)-based coordination polymers (CPs) materials have aroused great interest in the field of radiation detection. In this work, a X-ray responsive scintillating 1D Pb(II)-CP [Pb(adba)(DMF)] n (named as Pb-adba , H 2 adba = 4,4′-(9,10-anthracenediyl)dibenzoic acid, DMF = N , N -dimethylformamide) with favourable irradiation stability was synthesized by the self-assembly approach, which exhibits competitive sensitivity and detection limit toward X-ray than classical scintillators PbWO 4 (PWO), anthracene and some reported SMOFs. [ABSTRACT FROM AUTHOR]

• PL, XEL and sensing properties of Er3+ and Er3+/Yb3+ doped Gd 2 Zr 2 O 7 are studied. • A good radiation resistance is realized for these samples with pyrochlore structure. • Er3+ emissions keep stable under continuous X-ray excitation. • FIR of 2H 11/2 to 4S 3/2 is insensitive to excitation powers with S r-max of 1.1% K−1. • Er3+/Yb3+: Gd 2 Zr 2 O 7 can be used for optical thermometry and X-ray detection. A series of Er3+-doped and Er3+-Yb3+ co-doped Gd 2 Zr 2 O 7 phosphors were synthesized via hydrothermal method, and their multifunctional properties were studied in detail. The Raman spectra indicated that the products were the ordered pyrochlore phase of Gd 2 Zr 2 O 7 , which exhibited a good radiation resistance. The up-conversion (UC), down-conversion (DC) photoluminescence (PL) and X-ray excited luminescence (XEL) spectra of the Er3+: Gd 2 Zr 2 O 7 samples showed the similar spectra profiles, which were composed of the prominent green (2H 11/2 /4S 3/2 →4I 15/2) and weak red (4F 9/2 →4I 15/2) emissions. The co-doping of Yb3+ ions was beneficial for the improvement in UC PL but led to the reductions in DC PL and XEL. Besides, the X-ray induced green emissions demonstrated a high-sensitivity to the dose rate and a long-term stability against the continuous X-ray irradiation. Moreover, using the fluorescence intensity ratio (FIR) technique, the temperature sensing behaviors were analyzed based on the thermally coupled levels (TCLs) 2H 11/2 and 4S 3/2 of Er3+. The FIRs were found to be insensitive to the excitation power variation, and the optimal relative sensing sensitivity reached ~1.1%K−1 at 298 K. These characteristics may enable the studied system applicable for optical thermometry, X-ray detection and X-ray imaging. [ABSTRACT FROM AUTHOR]

In this study, a high-spatial-resolution scintillator-type X-ray detection system with a silicon separator was developed. The image characteristics are evaluated, and the approaches required for the practical application of the proposed system were discussed. X-ray inspection is an indispensable benefit in various fields; however, the spatial resolution of a scintillation-type X-ray detector is not as high as that of a direct-conversion X-ray imaging detector due to the scattering of the scintillator emissions. Therefore, the purpose of this study was to suppress such diffusion and improve the resolution to achieve a high-spatial-resolution scintillator-type X-ray imaging detector. Silicon wafers were processed to create small square holes in pixel patterns, and these holes were filled with the scintillator. The spatial resolution of the sample was then measured to confirm its improvement. The high-spatial-resolution of the scintillator-type detector was achieved using silicon separators. Moreover, appropriate noise characteristics and detection efficiency must be ensured to achieve good detection capability. Based on X-ray irradiation experiments and image quality evaluations, indicators were obtained for improving the image detection performance of the silicon separator in terms of noise and detection efficiency. Thus, the scintillator-type imaging detector with the high-spatial-resolution could be of practical use. • Spatial resolution of a scintillator-type X-ray image detector is improved. • Silicon wafer is processed to make small holes in a pixel pattern as a collimator. • Scintillator is separated by 400 μ m -thick silicon walls. • Significant results were obtained for scintillator-type imaging detectors. • Scintillation light intensity was successfully reduced by the silicon separator. [ABSTRACT FROM AUTHOR]

In this work the Bridgman crystal growth and scintillation properties of both undoped and Tl-doped Cs 3 Cu 2 I 5 are presented. This material is very attractive for gamma and X-ray detection applications, with a density of 4.53 g/cm3 and effective atomic number of 51.9. Undoped Cs 3 Cu 2 I 5 had a light yield of 41,500 photons/MeV, with an energy resolution of 4.4% at 662 keV. Thallium doping at 0.5 mol % resulted in a much-improved scintillation response, in which light yield increased to 98,200 photons/MeV and energy resolution reduced to 3.3% at 662 keV. The X-ray excited emission is centered at 442 nm for the undoped and 500 nm for the Tl-doped crystals. The undoped emission is broad, typical of excitonic emission, while thallium doping results in an even broader band with features of both the undoped and thallium defect-mediated emissions. • Transparent single crystals of undoped Cs 3 Cu 2 I 5 and Cs 3 Cu 2 I 5 (Tl) were grown via the Bridgman technique. • Phase purity was established via powder XRD analysis. • Undoped Cs 3 Cu 2 I 5 has 41,500 photons/MeV and 4.4% energy resolution at 662 keV. • Tl doping at 0.5 mol% improves light yield to 98,200 photons/MeV and energy resolution to 3.3%. [ABSTRACT FROM AUTHOR]

Tb3+ ions single-doped transparent oxyfluoride glass-ceramics (GC) containing LiYF 4 nanocrystals were prepared via a conventional high-temperature melt quenching way and subsequent further thermal-treatment. The microstructure and related luminescent properties of the composite materials were studied in detail. It was confirmed by XRD and TEM techniques that the precipitated particles in the glass phase of the GC590-4h sample were LiYF 4 nanocrystals having a size of approximately 26 nm. Compared to the PG sample, the luminescence intensity of the GCs at 378 nm light excitation was significantly enhanced and the corresponding lifetime was prolonged. This is because the Tb3+ ions are preferentially enriched in the precipitated low-phonon-energy LiYF 4 nanocrystals, which can effectively induce the reduction of non-radiative transitions. It is worth noting that the emission intensity of Tb3+ single-doped GCs containing LiYF 4 nanocrystals at 545 nm (5D 4 →7F 5) is also greatly improved (under X-ray excitation). The obtained results indicate that Tb3+ single-doped LiYF 4 GC may have the potential to be a novel scintillator applied to X-ray detection for the slow event. • Tb3+-doped transparent oxyfluoride glass ceramics containing LiYF 4 nanocrystals. • Have the potential of a novel scintillator. • The enhancement of the luminescence were improved under ultraviolet and X-ray excitation. [ABSTRACT FROM AUTHOR]