Search

In this paper, the effects of over-doping of Nd3+, Ho3+, Dy3+ and Ce3+ rare earth ions on the preparation and related properties of TSAG ceramics were investigated, and the results show that over-doping of rare earth ions has a certain effect on the micro-defects and transmittance of TSAG ceramics. The existence of a small number of fine particles which are not in the secondary phase on the grain surface, led to the decrease of the transmittance of the ceramic samples. The Verdet constant of rare earth ion over-doped TSAG ceramics is better than that of pure phase TSAG ceramics at the same test wavelength. In addition, YAG/TSAG-based bilayer composite structural ceramics were explored. The YAG/TSAG and YAG/2. 0% Ce:TSAG bilayer composite structural ceramics were successfully prepared, with sub-micron thickness transition layer formed on the contact surface, and the transmittance of the YAG/TSAG ceramics at 1 064 nm reaches 71. 0%. The successful preparation of YAG/TSAG-based composite ceramics broadens the application prospects of TSAG materials in high-power lasers. [ABSTRACT FROM AUTHOR]

Scintillators with high light yield, spatial resolution, and detection sensitivity are desirable for X‐ray imaging. Howerer, it remains challenging to improve the light yield and radiation detection capability of alkali metal rare‐earth fluoride (ALnF4). Herein, a type of Cu2+ ion heterovalent co‐doped LiLuF4:Tb,Cu microcrystalline scintillation material with high light yield, persistent, and thermostimulated luminescence is obtained by defect engineering. The heterovalent codoping strategy not only increases the radioluminescence (RL) intensity, but also introduces more carrier traps in the material to enhance the long‐afterglow and thermoluminescence intensity of LiLuF4:Tb microcrystals. After doping of 3 mol% Cu2+ ions, the RL efficiency is increased by 88.61%, and the X‐ray detection limit of LiLuF4:Tb,Cu reaches 2.7928 nGy·s‒1. This detectivity is considerably lower than the medical imaging requirements (5.5 µGy·s‒1). Furthermore, a large‐area flexible scintillation film of dimensions 30 × 30 cm2 is prepared to achieve high spatial resolution X‐ray imaging of 22 LP mm−1@MTF(modulation transfer function) = 0.2. Besides, this flexible film enables X‐ray imaging of curved objects and stores optical information for >48 h. This work provides a paradigm for improving the RL intensity and X‐ray detection sensitivity of alkali rare‐earth fluorides by crystal defect engineering, and enriches X‐ray high resolution extended imaging applications. [ABSTRACT FROM AUTHOR]

Currently, Faraday isolators and rotators for high‐power lasers are popular research topics; therefore, finding magneto‐optical materials with excellent Verdet constants and thermal properties is crucial. In this study, novel holmium scandium aluminum garnet (HoSAG) magneto‐optical ceramics were fabricated using vacuum sintering. This study improved the traditional ball milling method and pre‐synthesized powders with great sinterability after secondary ball milling and sieving. Different pre‐synthesis temperatures were found to have significant effects on the particle size and micromorphology of the synthesized powders. HoSAG ceramics with 0.05 wt% MgO sintering aid and held at 1700°C for 30 h reached a transmittance of 76.7% at 1550 nm. Meanwhile, HoSAG transparent ceramics maintain higher transmittance in the infrared region (>1500 nm) than terbium gallium garnet (TGG) crystals, indicating better application prospects. The Verdet constants of HoSAG magneto‐optical ceramics at 405, 532, 808, and 1064 nm were −421.5, −181.2, −65, and −32.3 rad T−1 m−1, respectively, which are slightly less than those of TGG magneto‐optical ceramics. Moreover, the thermal conductivity of HoSAG ceramics at 300.00 K was 4.89 W m−1 K−1, which is comparable to that of the TGG ceramics. [ABSTRACT FROM AUTHOR]

X-ray imaging has attracted considerable attention in the fields of environmental monitoring, industrial radiation detection, and biological health, and the key to X-ray imaging lies in the performance of scintillators. However, current single-crystal scintillators suffer from high cost, low doping concentration, and inhomogeneous distribution. Here, we report a (Y0.85−xLa0.15)2O3:xEu transparent ceramic scintillator prepared by vacuum sintering with uniform composition distribution and a transmittance of over 80.1% in the wavelength range of 632–1822 nm. The radioluminescence intensity of (Y0.79La0.15)2O3:6.0% Eu (λ = 611 nm) is 6.7 times higher than that of Bi4Ge3O12 (λ = 473 nm) and shows excellent radiation stability and fatigue resistance. In addition, the detection limit (129.8 nGy s−1) is lower than that required for X-ray diagnostics (5.5 μGy s−1). The prepared (Y0.85−xLa0.15)2O3:xEu transparent X-ray imaging demonstrates a high spatial resolution of 18.0 lp mm−1. Therefore, (Y0.85−xLa0.15)2O3:xEu transparent ceramics have the potential to be used for high-spatial-resolution X-ray imaging. [ABSTRACT FROM AUTHOR]

Analyze the causes of appearance quality defects of PC components. Different quality defects must be repaired by targeted repairing techniques and repair materials to achieve good repair results. According to the characteristics of the PC components products, basic repair motor mixture ratio was obtained after experiment, Cement:Sand:TiO2:Water reducing agent:EVA:HPMC=1:1.3:0.073:0.01:0.049:0.002, which would be used in the form of dry-mixed mortar. This way could effectively improve the repair effficiency and repair quality. [ABSTRACT FROM AUTHOR]

A promising candidate for X‐ray detection is layered hybrid double perovskites (LHDPs) with excellent structural stability, but their sensitivity is generally limited by unsatisfactory interlayer charge transport. Herein, employing one ethylenediamine (EDA) chain as a structural inducer, we successfully obtain unusual Dion‐Jacobson (DJ) phase LHDPs, (EDABr)4AgBiBr8 and (EDABr)4CuBiBr8, featuring a Ruddlesden‐Popper‐like (RP‐like) interlayer. Thanks to the bridging of bromine anions, organic cations are linked via charge‐assisted hydrogen bonds, where two ionic spacers are orderly woven into a supramolecular framework. Consequently, the RP‐like interlayer space is regulated by the dual‐ion‐woven supramolecular framework with embedded charge‐assisted hydrogen bond networks, remarkably enriching interlayer interactions and boosting charge transport. Through theoretical calculations, structural roles of the supramolecular framework are elucidated by extra orbital contribution and large diffusion barrier of Br anions. As proof of concept, the sensitivity of RP‐like devices up to 5250 μC Gyair−1 cm−2 is a record‐high of LHDP‐based X‐ray detectors for now, while a low detection limit (91 nGyair s−1) and outstanding radiation‐resistant capability (50 Gyair) are achieved. Moreover, an oriented membrane device is prepared to demonstrate high‐performance X‐ray tomography. These findings offer a brand‐new interlayer‐modulation strategy for the construction of sensitive and stable scintillation semiconductors. [ABSTRACT FROM AUTHOR]

Radiographic screens are widely used in high energy physics, national defense, aviation, radiodynamic therapy and medical imaging due to their scintillation materials that can transform high-energy particles or rays into ultraviolet (UV) visible light or other signals. In recent years, lanthanide doped fluoride nanocrystals (NCs) have attracted much attention due to their excellent optical properties and stability. In this work, multiple lanthanide-doped LiLuF 4 nanocrystal scintillation materials were synthesized by thermal decomposition. Among them, Tb-doped LiLuF 4 nanocrystals have high X-ray sensitivity and low detection limit (36.31 nGy s -1 ), which is much lower than the requirement of medical imaging dose rate. After the irradiation of 42.29 mGy s -1 X-ray for 1 hour, the intensity of radioluminescence basically remained unchanged. Based on the good properties of our nanocrystals, we further prepared the flexible film of nanocomposites with epoxy resin. This kind of uniform, large area, high loaded flexible film exhibits excellent performance in X-ray imaging with a spatial resolution greater than 20 line pairs per millimeter (LP/mm)., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)