Search Results (637)

In this study, we developed and characterized novel scintillators with Ce: LiCaAlF₆–CaF₂–Li₃AlF₆ and Ce: CaF₂–LiF–Li₃AlF₆ ternary systems for thermal neutron detectors. The eutectics were grown by the vertical Stochbarger-Bridgman (VB) technique, and their constituent phases were identified using powder X-ray diffraction and scanning electron microscopy. Radioluminescence spectra irradiated under an Ag-target X-ray tube and confirmed the 5d-4f and self-trapped exciton luminescence derived from Ce³⁺. Scintillation decay and pulse height measurements were performed using ²⁵²Cf and ⁶⁰Co sources. The Ce: CaF₂–LiF–Li₃AlF₆ sample exhibited approximately 5.6 times higher effective neutron sensitivity compared with a Ce: LiCaAlF₆ single crystal. A favorable decrease in the neutron discrimination threshold level (Q_th) due to reduced γ-ray emission was observed. ⁶Li-enriched Ce: CaF-based scintillators hold potential for nuclear decommissioning applications. Full article

This work reports the synthesis and characterization of Carbon Quantum Dots (CQDs) embedded in an organic–inorganic hybrid SiO₂: PMMA matrix, designed as a novel plastic scintillator material. The CQDs were synthesized through a solvo-hydrothermal method and incorporated using a sol–gel polymerization process, resulting in a mechanically durable and optically active hybrid. Structural analysis with X-ray diffraction and TEM confirmed crystalline quantum dots approximately 10 nm in size. Extensive optical characterization, including band gap measurement, photoluminescence under 325 nm UV excitation, lifetime evaluations, and quantum yield measurement, revealed a blue emission centered at 426 nm with a decay time of 3–3.6 ns. The hybrid scintillator was integrated into a compact cosmic ray detector using a photomultiplier tube optimized for 420 nm detection. The system effectively detected secondary atmospheric muons produced by low-energy cosmic rays, validated through the vertical equivalent muon (VEM) technique. These findings highlight the potential of CQD-based hybrid materials for advanced optical sensing and scintillation applications in complex environments, supporting the development of compact and sensitive detection systems. Full article

Fractures occur frequently in daily life, and before a surgeon implements treatment, the plan needs to be based on the radiologist’s imaging diagnosis of the X-ray. Despite progress in deep learning–based fracture detection, existing methods (e.g., two-stage detectors) face challenges such as small target leakage and sensitivity to background interference in complex medical images. To address these issues, this paper proposes the ASC-YOLO model, which employs the Scale-Sensitive Feature Fusion (SSFF) module to enhance multi-scale information extraction through cross-layer feature interaction. In addition, an Adaptive Decoupled Detection Head (AsDDet) is introduced to decouple the classification and regression tasks of the detection head, thereby improving the localization accuracy of small fracture regions and suppressing background noise. Experiments on a large fracture radiograph dataset, GRAZPEDWRI-DX, demonstrate that ASC-YOLO achieves 61% mAP@50, representing an 8% improvement over the baseline YOLO model (mAP@53%). It attains 95% mAP@50 for the fracture category and 97% mAP@50 for the metal category. Furthermore, the model was evaluated on a tumor dataset to verify its generalization capability. The proposed framework provides reliable technical support for accurate fracture screening, which is expected to reduce missed diagnoses and optimize treatment. Full article

The dynamic response in propane atmospheres at different voltages was investigated for samples made from powders of the semiconductor oxide CoSb₂O₆ synthesized using the microwave-assisted colloidal method. Powders of the compound calcined at 700 °C were studied with X-ray diffraction, confirming the CoSb₂O₆ crystalline phase. The microstructural characteristics of the oxide were analyzed using scanning and transmission electron microscopy (SEM/TEM), revealing a high abundance of nanorods, nanoplates, and irregular nanoparticles. These nanoparticles have an average size of ~21 nm. Using UV-Vis, absorption bands associated with the electronic transitions of the CoSb₂O₆’s characteristic bonds were identified, which yielded a bandgap value of ~1.8 eV. Raman spectroscopy identified vibrational bands corresponding to the oxide’s Sb–O and Co–O bonds. Dynamic sensing tests at 300 °C confirmed the material’s p-type semiconductor behavior, showing an increase in resistance upon exposure to propane. Critically, these tests revealed that the sensor’s baseline resistance and overall response are tunable by the applied voltage (1–12 V), with the highest sensitivity observed at the lowest voltages. This establishes a clear relationship between the electrical operating parameters and the sensing performance. The samples exhibited good operational stability, capacity, and efficiency, along with short response and recovery times. Extra-dry air (1500 cm³/min) was used as the carrier gas to stabilize the films’ surfaces during propane detection. These findings lead us to conclude that the CoSb₂O₆ could serve as an excellent gas detector. Full article

CT scanners are essential tools in modern medical imaging. Sudden failures of their X-ray tubes can lead to equipment downtime, affecting healthcare services and patient diagnosis. However, existing prediction methods based on a single model struggle to adapt to the multi-stage variation characteristics of tube lifespan and have limited modeling capabilities for temporal features. To address these issues, this paper proposes an intelligent prediction architecture for CT tubes’ remaining useful life based on a dual-branch neural network. This architecture consists of two specialized branches: a residual self-attention BiLSTM (RSA-BiLSTM) and a multi-layer dilation temporal convolutional network (D-TCN). The RSA-BiLSTM branch extracts multi-scale features and also enhances the long-term dependency modeling capability for temporal data. The D-TCN branch captures multi-scale temporal features through multi-layer dilated convolutions, effectively handling non-linear changes in the degradation phase. Furthermore, a dynamic phase detector is applied to integrate the prediction results from both branches. In terms of optimization strategy, a dynamically weighted triplet mixed loss function is designed to adjust the weight ratios of different prediction tasks, effectively solving the problems of sample imbalance and uneven prediction accuracy. Experimental results using leave-one-out cross-validation (LOOCV) on six different CT tube datasets show that the proposed method achieved significant advantages over five comparison models, with an average MSE of 2.92, MAE of 0.46, and R² of 0.77. The LOOCV strategy ensures robust evaluation by testing each tube dataset independently while training on the remaining five, providing reliable generalization assessment across different CT equipment. Ablation experiments further confirmed that the collaborative design of multiple components is significant for improving the accuracy of X-ray tubes remaining life prediction. Full article

Background/Objectives: In digital radiography imaging, dual-layer flat-panel detectors (DFDs), in which two flat-panel detector layers are stacked with a minimal distance between the layers and appropriate alignment, are commonly used in material decompositions as dual-energy applications with a single x-ray exposure. DFDs also enable more efficient use of incident photons, resulting in x-ray images with improved noise power spectrum (NPS) and detection quantum efficiency (DQE) performances as single-energy applications. Purpose: Although the development of DFD systems for material decomposition applications is actively underway, there is a lack of research on whether single-energy applications of DFD can achieve better performance than the single-layer case. In this paper, we experimentally observe the DFD performance in terms of the modulation transfer function (MTF), NPS, and DQE with discussions. Methods: Using prototypes of DFD, we experimentally measure the MTF, NPS, and DQE of the convex combination of the images acquired from the upper and lower detector layers of DFD. To optimize DFD performance, a two-step image registration is performed, where subpixel registration based on the maximum amplitude response to the transform based on the Fourier shift theorem and an affine transformation using cubic interpolation are adopted. The DFD performance is analyzed and discussed through extensive experiments for various scintillator thicknesses, x-ray beam conditions, and incident doses. Results: Under the RQA 9 beam conditions of 2.7 μGy dose, the DFD with the upper and lower scintillator thicknesses of 0.5 mm could achieve a zero-frequency DQE of 75%, compared to 56% when using a single-layer detector. This implies that the DFD using 75 % of the incident dose of a single-layer detector can provide the same signal-to-noise ratio as a single-layer detector. Conclusions: In single-energy radiography imaging, DFD can provide better NPS and DQE performances than the case of the single-layer detector, especially at relatively high x-ray energies, which enables low-dose imaging. Full article

The impact of 230-MeV Xe¹³² ion irradiation on the structural, optical, and luminescent properties of YAG:Ce single crystals is investigated over a fluence range of 10¹¹–10¹⁴ ions/cm². Optical absorption; cathodo-, X-ray, and photoluminescence; and X-ray diffraction are employed to analyze radiation-induced changes. Irradiation leads to the formation of Frenkel (F, F⁺) and antisite defects and attenuates Ce³⁺ emission (via enhanced nonradiative processes and Ce³⁺ → Ce⁴⁺ recharging). A redistribution between the fast and slow components of the Ce³⁺-emission is considered. Excitation spectra show the suppression of exciton-related emission bands, as well as a shift of the excitation onset due to increased lattice disorder. XRD data confirm partial amorphization and a high level of local lattice disordering, both increasing with irradiation fluence. These findings provide insight into radiation-induced processes in YAG:Ce, which are relevant for its application in radiation–hard scintillation detectors. Full article

Ghost imaging (GI) facilitates image acquisition under low-light conditions through single pixel measurements, thus holding tremendous potential across various fields such as biomedical imaging, remote sensing, defense and military applications, and 3D imaging. However, in order to reconstruct high-resolution images, GI typically requires a large number of single-pixel measurements, which imposes practical limitations on its application. Parallel ghost imaging addresses this issue by utilizing each pixel of a position-sensitive detector as a bucket detector to simultaneously perform tens of thousands of ghost imaging measurements in parallel. In this work, we explore the non-local characteristics of ghost imaging in depth, and by constructing a large speckle space, we achieve a reconstruction result in parallel ghost imaging where the field of view surpasses the limitations of the reference arm detector. Using a computational ghost imaging framework, after pre-recording the speckle patterns, we are able to complete X-ray ghost imaging at a speed of 6 min per sample, with image dimensions of 14,000 × 10,000 pixels (4.55 mm × 3.25 mm, millimeter-scale field of view) and a pixel resolution of 0.325 µm (sub-micron pixel resolution). We present this framework to enhance efficiency, extend resolution, and dramatically expand the field of view, with the aim of providing a solution for the practical implementation of ghost imaging. Full article

Over the past few decades, electron beams have been widely used to treat malignant and benign tumors located in the superficial regions of patients. This study utilized an inorganic scintillator (Gd₂O₂S:Tb)-based radiation detector to test its response characteristics in an electron-beam radiotherapy environment, in order to determine the application potential of this detector in electron-beam therapy. Owing to the extremely high time resolution of this inorganic scintillator detector (ISD), it is even capable of measuring the pulse information of electron beams generated by the accelerator. The results indicate that for certain accelerator models, such as the IX3937, the pulse pattern of the output electron beam is notably different from that during the output of X-rays, showing no significant periodicity. The experimental results also demonstrate that this ISD exhibits excellent repeatability and dose linearity (R² of 0.9993) when measuring electron beams. Finally, the PDD (Percentage Depth Dose) curves and OAR (Off-Axis Ratio) curves of the ISD were also tested under electron-beam conditions at 6 MeV and 9 MeV, respectively. Full article

State-of-the-art 2D sensitive semiconductor detectors developed within the SPARC collaboration can be utilized as dedicated Compton polarimeters in the hard X-ray regime. We report on the technique of Compton polarimetry utilizing such a detector and present a method to determine the linear polarization of an analyzed hard X-ray beam by means of Monte-Carlo-simulated data sets. Full article

Scattered light makes up a significant amount of recorded intensities during tomographic imaging, thereby leading to severe misinterpretation and artifacts in the reconstructed volume images. Correcting artificial intensities that stem from scattered light, therefore, is of primary interest and demands quantitative measurements. While numerous methods have been developed to reduce X-ray scattering artifacts, fewer methods deal with optical scattering. In this study, a measurement method for determining optical scattering in scintillators is presented with the aim of further developing correction algorithms. A theoretical model based on internal multiple reflections was developed for this purpose. This model assumes an additive exponential kernel with a certain scattering length to the system’s point spread function. This assumption was confirmed, and the scatter length was estimated from three new different kinds of experiments (hgap, rect, and LSF) on the BM18 beamline of the European synchrotron. The experiments further revealed significant differences in scattering proportion and length when different coatings are applied to the front and back faces of crystalline LuAG scintillators. Anti-reflective coatings on the backside show an effect of reducing the scattering magnitude while reflective coatings on the front side increase the proportion of the unscattered signal and, thus, show proportionally less scattering than black coating or no front coating. In particular, roughened black coating is found to worsen optical scattering. In summary, our results indicate that a combination of reflective (front) and anti-reflective (back) coatings yields the least optical scattering and, hence, the best image quality. Full article

With the dynamic development of imaging technologies and increasing demands in various industrial fields, neural networks are playing a crucial role in advanced design, monitoring, and analysis techniques. This review article presents the latest research advancements in neural network-based imaging, thermal, infrared, and X-ray technologies from 2005 to 2024. It focuses on two main research categories: ‘Technology’ and ‘Application’. The ‘Technology’ category includes neural network-enhanced image sensors, thermal imaging, infrared detectors, and X-ray technologies, while the ‘Application’ category is divided into image processing, robotics and design, object recognition, medical imaging, and security systems. In image processing, significant progress has been made in classification, segmentation, digital image storage, and information classification using neural networks. Robotics and design have seen advancements in mobile robots, navigation, and machine design through neural network integration. Object recognition technologies include neural network-based object detection, face recognition, and pattern recognition. Medical imaging has benefited from innovations in diagnosis, imaging techniques, and disease detection using neural networks. Security systems have improved in terms of monitoring and efficiency through neural network applications. This review aims to provide a comprehensive understanding of the current state and future directions of neural network-based imaging, thermal, infrared, and X-ray technologies. Full article

In 1900, Francis Herbert Jennison’s book The Manufacture of Lake Pigments from Artificial Colours was published in London. In the early 20th century, the technical literature focussing on synthetic dyes mainly dealt with their use for dyeing. Conversely, the literature on lake pigment manufacture is less comprehensive, and Jennison’s publication was the first monograph on this topic. His book comprises descriptions of the dyes, substrates, and various methods for lake making. Practical examples complete the work: sixteen colour plates with original samples of lake pigments showcase the practical effect on colour of the different dyes and preparation methods. Herein, we present an overview of the context of Jennison’s research and delve into a selection of formulations. Green lake pigment plates were sampled and analysed by liquid chromatography coupled with spectroscopic and spectrometric detectors and by X-ray fluorescence spectroscopy to correlate the chemical composition with the recipes reported in the book. Seldom or no longer used and unexplored historical dyes were detected, along with polyphenolic compounds possibly used as precipitating agents in lake pigment formulations. Moreover, the examination of two different editions of the Jennison manuscript (i.e., the English and German books) revealed different chemical profiles corresponding to the same lake pigment formulation. This emphasizes the significance of Jennison’s book, confirming how understanding of early formulations is needed to elucidate the later ones. Full article

X-ray ptychography is an ultrahigh resolution imaging technique widely used in synchrotron radiation facilities. Its imaging performance relies on the quality of the acquired signals. However, the X-ray detectors used often suffer from signal loss due to sensor gaps, beamstops, defective pixels, overexposure, or other factors, resulting in degraded image quality. To suppress and compensate for the effects of signal loss, we proposed the known probe approach to partially recover the lost signals and introduced the high probe divergence strategy by investigating the effects of probe divergence on reconstruction quality under signal loss conditions. Both simulation and experiment results show that high probe divergence can effectively suppress the impact of signal loss on reconstruction quality while using a known probe as the initial probe for reconstruction can largely recover missing signals in Fourier space, resulting in a much better image than using a guessed initial probe. These strategies allow for high-quality imaging in the presence of signal loss without secondary data acquisition, significantly improving experimental efficiency and reducing radiation damage compared to previous strategies. Full article

The scope of this study was to evaluate the response of Ce-doped gadolinium aluminum gallium garnet (GAGG:Ce) crystalline scintillator under medical X-ray irradiation for medical imaging applications. A 10 × 10 × 10 mm³ crystal was irradiated at X-ray tube voltages ranging from 50 kVp to 150 kVp. The crystal’s compatibility with several commercially available optical photon detectors was evaluated using the spectral matching factor (SMF) along with the absolute efficiency (AE) and the effective efficiency (EE). In addition, the energy-absorption efficiency (EAE), the quantum-detection efficiency (QDE) as well as the zero-frequency detective quantum detection efficiency DQE(0) were determined. The crystal demonstrated satisfactory AE values as high as 26.3 E.U. (where 1 E.U. = 1 μW∙m⁻²/(mR∙s⁻¹)) at 150 kVp, similar, or in some cases, even superior to other cerium-doped scintillator materials. It also exhibits adequate DQE(0) performance ranging from 0.99 to 0.95 across all the examined X-ray tube voltages. Moreover, it showed high spectral compatibility with commonly used photoreceptors in modern day such as complementary metal–oxide–semiconductors (CMOS) and charge-coupled-devices (CCD) with SMF values of 0.95 for CCD with broadband anti-reflection coating and 0.99 for hybrid CMOS blue. The aforementioned properties of this scintillator material were indicative of its superior efficiency in the examined medical energy range, compared to other commonly used scintillators. Full article