Effects of Sr2+ doping on the X-ray detection properties of Cs3Cu2I5 crystal

Abstract Tidal disruption events (TDEs), in which stars are disrupted by supermassive black holes, have been proposed as potential sources of high-energy neutrinos through hadronic interactions. X-ray-bright TDEs provide dense photon fields conducive to neutrino production via proton-photon (pγ) processes. We conducted a time-dependent unbinned likelihood analysis of ten years (2008 − 2018) of IceCube muon-track data, focusing on ten TDEs with confirmed X-ray detections during this period. We report a neutrino flare candidate spatially and temporally coincident with the TDE ATLAS17jrp, occurring 19 days after the onset of its X-ray activity and lasting for 56 days, with a post-trial p-value of 0.01. This significance is modest, representing a hint of an association. We illustrate the neutrino emission using a simple lepto-hadronic model, where X-ray photons serve as target fields. While this model can account for the neutrino data around 100 TeV, the low-energy neutrinos may imply contributions from an additional component. Although constrained by the sample size of X-ray-detected TDEs, these results underscore the need for high-cadence X-ray monitoring and future neutrino observatories to further explore the connection between TDEs and high-energy neutrinos.

We report the preparation of flexible scintillation films based on Ag6N6S12C54H48 (Ag-R-4PTT) clusters formed by in-situ crystallization within a polymer matrix. The Ag-R-4PTT clusters exhibit thermally activated delayed fluorescence with a high photoluminescence quantum yield of 93.1%. Controlled crystallization yields microcrystalline clusters in poly(vinylpyrrolidone)/thermoplastic polyurethane matrices with excellent radioluminescence performance and high structural stability, leading to a light yield of 33 400 photons MeV-1 and an X-ray detection limit down to 231 nGyair s-1. The scintillation films retain high mechanical flexibility, optical transmittance, and water-resistance, achieving a spatial resolution of 21 lp mm-1 for X-ray imaging. This study introduces a general strategy to stabilize Ag clusters via coordination engineering as well as in-situ crystallization, offering a promising platform for flexible radiation detection and high-resolution imaging.

Real-time dynamic and three-dimensional (3D) X-ray imaging are the most challenging types of X-ray imaging technology, placing more rigorous standards on scintillators. Lead-based (Pb2+) organic-inorganic hybrid halide (OIHH) scintillators with high X-ray absorption coefficients have been demonstrated to exhibit excellent scintillation performance. However, their toxicity and instability hindered further development, and it is necessary to explore novel low-toxic metal-based OIHHs possessing excellent scintillation performance. Antimony-based (Sb3+) OIHHs are not only environmentally friendly, but also show good stability compared to Pb2+-based OIHHs, which make them promising candidates as excellent scintillators. Currently, the understanding of Sb3+-based OIHH scintillators for X-ray detection and imaging is still in infancy and requires further exploration. Herein, we designed two Sb3+-based OIHH crystals of (BPP)2SbCl5 (CP1) and (BPP)2SbCl5 0.5 H2O (CP2), which have very similar crystal structures except the introduction of water molecules in CP2. Experimental and theoretical results reveal that CP2 has larger lattice distortion and smaller freedom of motion, which can promote the self-trapped excitons emissions. A flexible scintillator screen based on CP2 crystals was prepared and applied for real-time dynamic and 3D X-ray imaging, which is the first time for Sb3+-based OIHH scintillators and significantly broadens the potential of Sb3+-based OIHH scintillators.

Polycrystalline perovskites have attracted extensive interest in the field of X-ray detection/imaging due to their excellent compatibility with scalable processing. However, despite recent advances, polycrystalline perovskite X-ray direct detectors are plagued by the relatively high dark currents in imaging applications. Herein, we experimentally demonstrate that the dark current of polycrystalline perovskite X-ray detectors can be controlled by tuning the composition of perovskites. In particular, the incorporation of bromine (Br) into methylammonium lead iodide (MAPbI3) modifies the bandgap, increases electrical resistance, reduces the defects, improves the crystallinity, and suppresses the nonradiative recombination, thereby comprehensively causing the reduction of dark currents. At a doping concentration of 15%, the bulk resistivity of MAPb(I1-xBrx)3 layer increases to 1.3 × 108 Ω·cm, leading to a low dark current density down to 0.801 nA·cm-2. Consequently, the X-ray detector shows a low detection limit of 118.4 nGyair s-1 and a sensitivity to noise-current ratio of 7.27 × 1011 μC Gyair-1 A-1. By integrating the Br-doped MAPbI3 X-ray detector into a readout integrated circuit, the X-ray imager exhibits high-quality imaging capability. The results reveal a simple and effective strategy to minimize dark currents in perovskite X-ray detectors, and the detector has high potential in high-performance X-ray flat-panel imagers for industrial and medical applications.

PurposeMedical image quality assessment is crucial, as poor-quality images can lead to misdiagnosis. Manual quality labeling is tedious for large studies and may produce misleading results. While automated analysis of image quality has been studied, little focus has been given to explaining and quantifying methodologies. This study proposes an explainable image quality assessment system, validated in two contexts: foreign object detection in Chest X-Rays (Object-CXR) and Left Ventricular Outflow Tract (LVOT) detection in Cardiac MRI.MethodsOur explainable pipeline employs NormGrad, an algorithm that efficiently localizes image quality issues by comparing the classifier’s saliency maps against several baseline saliency detectors. Additionally, a novel metric, the Difference of Means (DoM), is introduced to assess the consistency of saliency detectors across different network architectures.ResultsWe compare NormGrad with a range of saliency detection methods and demonstrate its superior performance in measuring the faithfulness of the saliency detectors. Specifically, NormGrad achieved a repeated Pointing Game score of 0.863 for Object-CXR and 0.778 for LVOT datasets, significantly outperforming other saliency detectors. Furthermore, our explainable pipeline shows strong consistency, with DoM scores of 0.001 for Object-CXR and 0.005 for LVOT datasets, indicating high reliability across different reproduced models. The code and experiments are publicly available at https://github.com/canerozer/explainable-iqa.ConclusionThe proposed system, powered by NormGrad, significantly improves the reliability of automated medical image quality evaluations. The introduction of the Difference of Means metric offers a unique way to assess saliency detector consistency, supporting NormGrad’s potential for widespread clinical adoption.

Bi/Sb-based halide ferroelectrics have become promising lead-free alternatives due to their excellent stability and environmental friendliness. However, their wide bandgaps and limited charge-carrier mobility-lifetime (µτ) product impede their optoelectronic performance. Here, we report a new eco-friendly method for growing lead-free halide ferroelectric solid-solution (HDA)Sb1-xBixI5 (x=0-1) (HDA=hexane-1,6-diammonium), by isothermal evaporation from a biomass-derived solvent, γ-valerolactone (GVL). The solid-solution strategy, good material stability,- and high-quality centimeter-sized single-crystals not only endow the (HDA)Sb0.39Bi0.61I5 with the narrowest bandgap of 1.64eV among Bi/Sb-based halide ferroelectrics, but also enhance its µτ product by approximately two orders of magnitude compared with the parent (HDA)SbI5. Benefiting from these attributes and the intrinsic ferroelectric spontaneous polarization, the X-ray detector based on (HDA)Sb0.39Bi0.61I5 exhibits excellent self-powered detection performance with a high sensitivity of 1,040 µC Gyair -1 cm-2 and a low detection limit of 0.25 nGyair s-1. More excitingly, its detection sensitivity can reach 17,560 µC Gyair -1 cm-2, which is the highest among reported halide ferroelectrics, and superior to that of most halide detectors. This work opens new avenues for the rational engineering of Bi/Sb-based halide ferroelectrics for advanced optoelectronic applications.

Dual-energy X-ray imaging is of significant interest for medical diagnostics, security screening, and industrial inspection; however, existing approaches based on photon-counting or multilayer detectors often increase the system complexity. Here, we introduce a surface-treated perovskite thin-crystal device with an engineered electrode architecture, enabling high-sensitivity, dual-energy X-ray imaging. With surface treatment, the device achieves enhanced optoelectronic performance with a sensitivity of 4.5 × 104 μC·Gy1-·cm-2, a low detection limit of 13.8 nGy·s-1, and greatly improved device stability. By tailoring the internal electric field distribution through the electrode design, the device achieves controlled absorption of X-ray photons with different energies, thereby exhibiting an excellent energy discrimination capability. Subtraction imaging of overlapping low- and high-density objects was successfully reconstructed by the algorithmic processing of response currents. Furthermore, precise material differentiation was achieved through introducing the ratio of X-ray absorption coefficients (μL/μH), which cannot be realized by conventional X-ray detectors. Our study provides a simple and efficient route for dual-energy X-ray imaging and offers new perspectives for the development of multifunctional perovskite-based devices.

Metal halide perovskites have attracted significant attention as emerging semiconductors for low-dose X-ray detection. Their high atomic number elements, strong absorption, and long carrier diffusion lengths make them promising for medical imaging applications. This review highlights how advances in nanoscale science and nanotechnology are reshaping perovskite-based X-ray detectors. We discuss the influence of dimensionality, defect control, and interface engineering on charge generation and transport, together with the role of nanomanufacturing strategies such as confined crystallization and scalable printing. Recent progress in nanoscale characterization provides insight into carrier dynamics and stability, enabling a deeper understanding of low-dose operation. Finally, we outline forward-looking opportunities in flexible and wearable devices, integration with medical systems, and the development of sustainable materials. By framing perovskite X-ray detection within the broader context of nanoscience, we emphasize its potential to deliver efficient, reliable, and transformative platforms for future medical imaging.

A challenge with state-of-the-art projection x-ray imaging technologies is their limited ability to identify unknown substances. Here, we develop an intelligent multienergy x-ray imaging technique capable of precisely distinguishing different substances and labeling them with diverse colors. Our design uses a series of x-ray attenuation coefficient ratios under different x-ray energies as substance-specific markers. For this purpose, unipolar perovskite x-ray detectors are carefully engineered to resolve the x-ray energies into seven channels using a customized algorithm. Combining machine learning and a comprehensive x-ray attenuation ratio database of common materials enables accurate recognition of low-density biological tissues composed of light elements with similar atomic numbers. By transforming the intensity scale in conventional x-ray images into an attenuation coefficient ratio, our work presents a proof of concept for color-coded x-ray imaging, highlighting its potential for applications in energy-dispersive computed tomography, targeted drug delivery, quantum physics, and universe exploration.

All-inorganic perovskite CsPbBr3 crystals have demonstrated considerable promise in γ-ray and X-ray detection, owing to their excellent optoelectronic properties. However, the growth of large single crystals (SCs) and the stability of CsPbBr3-based X-ray detectors under high-energy radiation exposure remain unexplored. In this study, a two-inch CsPbBr3 single-crystal is grown using the vertical Bridgman (VB) method, and its irradiation resistance in X-ray detection performance is investigated after exposure to 60Co γ-ray radiation. Compared with unirradiated samples, the crystals irradiated with a dose of 10Mrad exhibit a higher trap density (1.59 × 1010 cm-3) and a lower resistivity (8.2 × 107 Ω cm). However, the Bi/CsPbBr3/Au devices with asymmetric electrode structure exhibit an enhanced signal-to-noise ratio (14), a stable and low dark current density (7 nA cm-2) with a current drift of 5.8 × 10-15 A cm-1 s-1 V-1, and a high sensitivity of 55722 µC Gyair-1 cm-2 for X-ray detection at an electric field of 3000V cm-1. Moreover, the irradiated device remained stable X-ray response characteristics after 220 days aging. These findings highlight the exceptional defect tolerance and irradiation stability of CsPbBr3 devices for high-performance radiation detections, offering critical insights for their long-term deployment in high-radiation environments.

2D perovskite single crystals (SCs) demonstrate significant potential for developing low-cost, stable, and low dose X-ray detection. However, the large interlayer spacing in 2D perovskite results in low carrier mobility, limiting the sensitivity enhancement of X-ray detection. Herein, a tandem detector is designed and assembled for the first time to solve the critical issue of low carrier transport efficiency in 2D perovskite SCs. The tandem SC detector establishes efficient cross-layer charge transport channels through a "layered synchronous collection" strategy, enabling a "short-range transport" mechanism. The unique "longitudinal short-range transport" reduces carrier transport distance and then decreases recombination and trap capture, thus significantly enhanced carrier collection efficiency. Consequently, these detectors not only maintain low dark current but also exhibit a higher response current than single-junction counterparts, resulting in superior X-ray detection performance. Specifically, the tandem SC detectors achieved a high sensitivity of 5218 µC Gy-1 cm-2, a low detection limit of 2.2 n Gy s-1, and a short response time of 1.8ms. Furthermore, the tandem detectors retain original response after continuous X-ray irradiation with a high dose of 2.4Gy. The combination of high stability and sensitivity enables the tandem SC detectors achieved high-definition imaging at 12.5 lp mm-1.

The FAMU experiment at RIKEN-RAL aims to measure with high precision the ground state hyperfine splitting (1S HFS) of muonic hydrogen and thus determine the proton Zemach radius. A novel method based on the detection of X-rays emitted by μO after the muon transfer from μH to oxygen is used. A high performance X-ray detectors' system and an innovative mid-infrared (MIR) laser system were therefore developed. The X-ray detector's system is mainly based on LaBr3:Ce crystals read by SiPM arrays. From the MIR laser frequency value, known with precision < 10-5, the energy of the HFS transition may be accurately measured, as ΔE HFS = hν HFS.

Metal halide perovskite is promising semiconducting materials for sensitive X-ray detection and imaging. However, incompatibility with thin-film transistor (TFT) backplanes has posed a major challenge to the commercial deployment of...

X-ray detection is crucial for medical imaging and industrial non-destructive testing. However, conventional materials face limitations such as low absorption efficiency, high dark current, and the necessity for external power bias. This study presents a novel inorganic polar oxide crystal, Cs2TeMo3O12, as a high-performance direct-conversion X-ray detector material, particularly for self-powered applications. The stereochemically active lone-pair electrons of Te4+ induce a non-centrosymmetric polar structure, which generates a built-in electric field that enables efficient charge carrier separation under zero bias. Along the polar Z-direction, the crystal exhibits a high resistivity of 5.08 × 1014 Ωcm, a considerable mobility-lifetime product of 1.08 × 10‒3 cm2 V‒1, and an excellent sensitivity of 436 µC Gyair ‒1 cm‒2 under a 2000Vcm-1 electric field. Most notably, the device operates effectively in a self-powered mode, achieving a sensitivity of 178 µC Gyair ‒1 cm‒2 and an ultralow detection limit of 10.5 nGyair s‒1. Furthermore, it demonstrates exceptional operational stability with negligible dark current drift. This work not only introduces Cs2TeMo3O12 as an exceptional candidate for low-dose and self-powered X-ray detection but also provides a novel design strategy leveraging lone-pair electrons for developing advanced photoelectric materials.

Developing novel high-performance materials to enhance the precision and reliability of X-ray detection technology is critically important for medical diagnosis, industrial non-destructive testing, and scientific research. The monoclinic potassium double...

The zero-dimensional (0D) bismuth halide perovskites are attractive candidate semiconductors for X-ray detection due to their low biotoxicity and inhibited ionic migration. However, achieving stable X-ray detection applications of 0D...

A halogen-bond-induced polar hybrid perovskite exploits its bulk photovoltaic effect and heavy-metal framework for self-powered X-ray detection, achieving a sensitivity of 221.7 μC Gy −1 cm −2 and a low detection limit of 16.3 nGy s −1 at 0 V bias.

ZnO is an essential material used in various devices, but its performance can be significantly enhanced by introducing or removing defects, such as oxygen and zinc vacancies. In this article, we explore the relationship between different types of defects in pure and Al/Ga-doped ZnO and their corresponding optical and electronic properties, which are vital for X-ray detection. The nanoparticles were initially synthesized using the sol-gel auto-combustion method, with calcination temperatures of 400 °C, 500 °C, and 600 °C. The samples were then analyzed using multiple techniques, including XRD, FESEM, FTIR, photoluminescence (PL), electron paramagnetic resonance (EPR), and positron annihilation lifetime spectroscopy (PALS). Subsequently, DFT+U calculations were conducted to examine the electrical, optical, and theoretical EPR properties, as well as to identify defects that occur at different calcination temperatures. Analyzing the connection between defects and PL spectra in X-ray scintillation detectors, along with exploring the relationship between electron and hole concentrations in X-ray semiconductor detectors, provides valuable insights into the fundamental properties of ZnO. These insights pave the way for utilizing ZnO in developing next-generation scintillation and semiconductor X-ray detection technologies.

Ce3+ doped BaO–Gd2O3–P2O5 glass: New glass scintillator for X-rays detector and imaging applications