Development Of Detectors Research Articles

A noninvasive blood glucose detection method with strong time adaptability based on fuzzy operator decision fusion and dynamic spectroscopy characteristics of PPG signals.

PPG signals are a new means of non-invasive detection of blood glucose, but there are still shortcomings of poor time adaptability and low prediction accuracy of blood glucose quantitative models. Few studies discuss prediction accuracy in the case of a large time interval span between modeling and prediction. This paper proposes an automatic optimal threshold baseline removal algorithm based on variational mode decomposition (AOT-VMD), which can adaptively eliminate high-frequency noise and baseline interference for each decomposed IMF modal component and reduce the baseline difference of PPG signals from different days. Furthermore, a fuzzy integral multi-model decision fusion algorithm based on error weight is proposed. The fuzzy integral operator is introduced to make the features with large contributions in each sub-model maintain a high-weight value in the overall prediction mechanism, which improves the prediction accuracy of blood glucose. In this paper, a self-developed portable PPG glucose meter is used to collect PPG signals, and the true blood glucose values for 8 consecutive days are collected by CGM. The proposed algorithm is used to build a model with the first day's data and predict the blood glucose values for the remaining 7 days. The experimental results show that the AOT-VMD preprocessing algorithm and the quantitative regression algorithm of the fuzzy integral multiple model decision fusion algorithm proposed in this paper perform well in measurement accuracy and time adaptability compared with the traditional methods. In addition, the proposed method requires less invasive calibration samples in the modeling stage, achieving high-precision prediction for a long period. 100% of the samples are located in areas A and B of the Clarke area in this experiment, and the algorithm has strong time generalization ability. This innovative method can promote the development of a home blood glucose noninvasive detector.

Toward Versatile Small Object Detection with Temporal-YOLOv8.

Deep learning has become the preferred method for automated object detection, but the accurate detection of small objects remains a challenge due to the lack of distinctive appearance features. Most deep learning-based detectors do not exploit the temporal information that is available in video, even though this context is often essential when the signal-to-noise ratio is low. In addition, model development choices, such as the loss function, are typically designed around medium-sized objects. Moreover, most datasets that are acquired for the development of small object detectors are task-specific and lack diversity, and the smallest objects are often not well annotated. In this study, we address the aforementioned challenges and create a deep learning-based pipeline for versatile small object detection. With an in-house dataset consisting of civilian and military objects, we achieve a substantial improvement in YOLOv8 (baseline mAP = 0.465) by leveraging the temporal context in video and data augmentations specifically tailored to small objects (mAP = 0.839). We also show the benefit of having a carefully curated dataset in comparison with public datasets and find that a model trained on a diverse dataset outperforms environment-specific models. Our findings indicate that small objects can be detected accurately in a wide range of environments while leveraging the speed of the YOLO architecture.

Cutting-Edge Developments in Metal Halide Perovskites Core/Shell Heterocrystals: from Photodetectors to Biomedical Applications.

In recent years, the performance of metal halide perovskite (MHP)-based detectors (photon, biomedical, and X-ray detection) has significantly improved, resulting in higher carrier mobilities, longer carrier diffusion lengths, and excellent absorption coefficients. However, the widespread adoption of halide perovskites has been hindered by issues related to their stability and toxicity. Various strategies have been adopted to address these challenges, focusing on enhancing ambient stability and reducing toxicity by encapsulating MHPs within stable and robust host materials, such as silicon compounds, metal oxides, chalcogenides, and lead-free perovskites. This review focuses on recent developments in hybrid nanostructure-based detectors (photon, biomedical, and X-ray), particularly core/shell architectures, and provides a comprehensive analysis of techniques for mitigating degradation due to light and oxygen exposure, UV irradiance, and thermal effects. This review enhances the understanding of current advancements in core/shell-based detectors.

UTHP spectrometer: an ultra-thin and high-performance imaging spectrometer for ocean color remote sensing in broadband

The principle of ocean color detection involves using satellite sensors to capture variations in received signals, which are subsequently analyzed to infer the concentrations of various components responsible for ocean color changes. In recent years, significant research advancements have been achieved, centered on the development of ocean color detectors and the analysis of the resulting data. We have developed an innovative ultra-thin high-performance (UTHP) scanning imaging spectrometer for ocean color remote sensing across the near ultraviolet-visible-near infrared (NUV-VIS-NIR) spectrum. This spectrometer overcomes the bulkiness of conventional equipment by integrating a waveguide platform that replaces traditional optical elements with a single flat glass panel, featuring curved surfaces and high-reflectivity coatings to perform essential optical functions. We believe this to be a novel design that greatly reduces the size and weight of the device, making it highly suitable for deployment on various platforms, including aircraft and satellites. The optical system underwent extensive testing, including simulations using Zemax software and physical prototyping, achieving a spectral resolution of less than 3 nm across the 400-1000 nm waveband while maintaining low distortion. The UTHP spectrometer’s compactness, lightweight design, and exceptional performance mark a significant advancement in imaging spectrometry, with the potential to transform remote sensing by providing more efficient, accessible methods for studying expansive oceanic regions.

QCMOS Detectors and the Case of Hypothetical Primordial Black Holes in the Solar System, near Earth Objects, Transients, and Other High-cadence Observations

Abstract Recent progress with CMOS detector development has opened new parameter space for high cadence time resolved imaging of transients and fast proper motion solar system objects. Using computer simulations for a ground-based 1.23 m telescope, this research note illustrates the gain of a new generation of fast readout low noise qCMOS sensors over CCDs and makes the case for high precision monitoring of asteroid orbits that can potentially shed light on the hypothetical existence of low mass primordial black holes, as well as for other applications requiring high speed imaging.

Light-emitting diode-based absorbance detectors for flow-through analysis in analytical chemistry: A tutorial

The development of light-emitting diodes (LEDs) has played a significant role supporting many recent advances made in chemical analysis. Their small size, low power consumption, and semi-monochromaticity make them ideal light sources for portable photometric devices used in field and on-site analysis, environmental monitoring, and industrial applications, such as process analytical technology (PAT) and continuous real-time analysis. This tutorial provides an overview and critical comparison of the key components in LED-based absorbance detectors, including light sources, optical fibres, flow cells, and photodetectors. Fundamental aspects of LEDs relating to their use in such simple detectors are discussed in detail, along with the development of multi-wavelength detectors that incorporate multiple LEDs. The tutorial also details the different methodologies for assessing and characterising the LED-based absorbance detectors. Finally, this tutorial presents some selected applications of LED based photometric detectors in gas sensing, flow injection analysis (FIA), and coupled with separation techniques such as ion chromatography, liquid chromatography, and capillary zone electrophoresis (CZE).

Studies of GAGG:Ce scintillators for space missions dedicated to Terrestrial Gamma-Ray Flashes and Gamma-Ray Bursts observation

Fast Gamma ray Spectrometer (FGS) is an on-going detector development for the observation of transient gamma ray events such as Terrestrial Gamma ray Flashes (TGFs) produced in Earth’s thunderstorms and Gamma Ray Bursts (GRBs) produced in the far Universe. In this work, we compare different Cerium-doped Gadolinium Aluminium Gallium Garnet (GAGG:Ce) scintillators, associated with Silicon Photo-Multipliers (SiPMs), quantifying their performances at atmospheric pressure and under vacuum, with different surface conditions. We also study their afterglow following proton irradiation, similar to what will be observed in space environment. Our measurements with GAGG:Ce scintillators after proton irradiation confirm that GAGG:Ce can be used in space.

Nonstoichiometry Promoted Solventless Recrystallization of a Thick and Compact CsPbBr3 Film for Real-Time Dynamic X-Ray Imaging.

Inorganic CsPbBr3 perovskite emerges as a promising material for the development of next-generation X-ray detectors. However, the formation of a high-quality thick film of CsPbBr3 has been challenging due to the low solubility of its precursor and its high melting point. To address this limitation, a nonstoichiometry approach is taken that allows lower-temperature crystallization of the target perovskite under the solventless condition. This approach capitalizes on the presence of excess volatile PbBr2 within the CsPbBr3 film, which induces melting point depression and promotes recrystallization of CsPbBr3 at a temperature much lower than its melting point concomitant with the escape of PbBr2. Consequently, thick and compact films of CsPbBr3 are formed with grains ten times larger than those in the pristine films. The resulting X-ray detector exhibits a remarkable sensitivity of 4.2 × 104 µC Gyair -1 cm-2 and a low detection limit of 136 nGyair s-1, along with exceptional operational stability. Notably, the CsPbBr3-based flat-panel detector achieves a high resolution of 0.65 lp pix-1 and the first demonstration of real-time dynamic X-ray imaging for perovskite-based devices.

The Time Response of a Uniformly Doped Transmission-Mode NEA AlGaN Photocathode Applied to a Solar-Blind Ultraviolet Detecting System

Due to the excellent quantum conversion and spectral response characteristics of the AlGaN photocathode, it has become the most promising III-V group semiconductor photocathode in solar-blind signal photoconversion devices in the ultraviolet band. Herein, the influence factors of the time-resolved characteristics of the AlGaN photocathode are researched by solving the photoelectron continuity equation and photoelectron flow density equation, such as the AlN/AlGaN interface recombination rate, AlGaN electron diffusion coefficient, and AlGaN activation layer thickness. The results show that the response time of the AlGaN photocathode decreases gradually with the increase in AlGaN photoelectron diffusion coefficient and AlN/AlGaN interface recombination rate, but the response time of the AlGaN photocathode gradually becomes saturated with the further increase in AlN/AlGaN interface recombination rate. When the thickness of the AlGaN photocathode is reduced from 250 nm to 50 nm, the response time of the AlGaN photocathode decreases from 63.28 ps to 9.91 ps, and the response time of AlGaN photocathode greatly improves. This study provides theoretical guidance for the development of a fast response UV detector.

Development of a multi-layer high-efficiency GEM-based neutron detector for spallation sources

Neutron detection is nowadays mostly based on 3He gas detectors, but its shortage and the continuous upgrades of the neutron facilities require new devices to perform experiments with maximum performances. This work presents a new detector based on the Gas Electron Multiplier (GEM) combined with several boron layers. This detector combines the features of GEM technology with the properties of boron as a neutron converter and the device is produced to sustain high neutron fluxes with high detection efficiency. The detector has been characterised at the ISIS Pulsed Neutron and Muon Source (UK). Based on the analysis of our results, the detector has shown a good response to thermal and epithermal neutrons reaching a detection efficiency of 16% at 1.8 Å (25 meV). The good detection efficiency (even increasable with the addition of further boron GEM foils) and the good time resolution, make the detector a unique device for the neutron techniques. In particular, its use can easily be envisaged in techniques involving neutron transmission measurements, that require high fluxes impinging on the detectors, with the added bonus of a 2D-resolved capability due to the padded anode.

Особливості і розвиток технологій виявлення витоків трубопроводів тепло- та водопостачання в умовах зношеності та мілітарних впливів

The article is dedicated to analyzing the current state of underground heat and water supply pipelines in Ukraine, particularly under conditions of significant wear and tear and military impacts. The challenges associated with the operational detection of hidden leaks are exami¬ned, as well as the capabilities of known methods for identifying damaged sections and leak locations. The development of acoustic and correlation leak detectors is discussed as a promi¬sing direction for improving pipeline diagnostics in war conditions and amid network dete¬rioration. Several innovations are proposed, including a new parametric correlation method, spatial-frequency selection of useful leak signals, and other advancements to enhance the diag¬nostics of critical infrastructure. These measures aim to improve the effectiveness of leak de¬tection, ensure the continuity of essential services, and strengthen the resilience of the energy system in the face of current challenges.

Study on Photon Beam Imaging Properties of CsPbBr3-PP Scintillator: Monte Carlo Simulation Approach

Perovskite scintillators have garnered significant interest in the realm of gamma-ray imaging in the past few years. Here, a comprehensive investigation into the gamma-ray imaging properties of CsPbBr3-PP composite scintillators is presented, wherein the Monte Carlo simulation approach offered by Geant4 is utilized. The primary focus is on the point spread function and modulation transfer function of the material, elucidating the nuanced interactions between gamma-ray energy, scintillator thickness, and their resultant imaging capabilities. A key aspect of this study is the exploration of the nonlinear and inverse effect of scintillator thickness and the energy of the photon beam on the imaging quality, highlighting the trade-offs between energy deposition and image resolution. This research underscores the importance of optimizing the scintillator design to balance these factors, catering to specific applications in high-energy detection and imaging. This work not only contributes significantly to the field of material sciences and radiographic imaging, but also provides practical insights for the development of more effective scintillator-based detectors. The findings of this study have broad implications for the design and application of perovskite scintillators in various high-tech industries and scientific research.

Development and benchmarking of multilingual code clone detector

The diversity of programming languages is growing, making the language extensibility of code clone detectors crucial. However, this is challenging for most existing clone detection detectors because the source code handler needs modifications, which requires specialist-level knowledge of the targeted language and is time-consuming. Multilingual code clone detectors make it easier to add new language support by providing syntax information of the target language only. To address the shortcomings of existing multilingual detectors for language scalability and detection performance, we propose a multilingual code block extraction method based on ANTLR parser generation, and implement a multilingual code clone detector (MSCCD), which supports the most significant number of languages currently available and has the ability to detect Type-3 code clones. We follow the methodology of previous studies to evaluate the detection performance of the Java language. Compared to ten state-of-the-art detectors, MSCCD performs at an average level while it also supports a significantly larger number of languages. Furthermore, we propose the first multilingual syntactic code clone evaluation benchmark based on the CodeNet database. Our results reveal that even when applying the same detection approach, performance can vary markedly depending on the language of the source code under investigation. Overall, MSCCD is the most balanced one among the evaluated tools when considering detection performance and language extensibility.

The European strategy and detector R&D program

The latest update of the European Strategy for Particle Physics stimulated the preparation of the European Detector Roadmap document in 2021 by the European Committee for Future Accelerators ECFA. This roadmap, defined during a bottom-up process by the community, outlines nine technology domains for HEP instrumentation and pinpoints urgent R&D topics, known as Detector R&D Themes (DRDTs). Task forces were set for each domain, leading to Detector R&D Collaborations (DRDs), now hosted at CERN. After an intensive period over the last months, seven DRD collaborations have been established which are now starting to set up their collaboration structures and begin to work. One is still in the preparation phase.In this publication, I will give an overview of the set-up process and the current status of all DRD collaborations covering detector developments in the field of gaseous detectors, noble liquid detectors for rare event searches, semiconductor detectors, photodetectors and concepts for particle ID, quantum sensors, calorimetry, electronics for HEP instrumentation and mechanical and integration aspects.

Impact of strain relaxation on the growth rate of heteroepitaxial germanium tin binary alloy

The growth of high-quality germanium tin (Ge1–y Sn y ) binary alloys on a Si substrate using chemical vapor deposition (CVD) techniques holds immense potential for advancing electronics and optoelectronics applications, including the development of efficient and low-cost mid-infrared detectors and light sources. However, achieving precise control over the Sn concentration and strain relaxation of the Ge1–y Sn y epilayer, which directly influence its optical and electrical properties, remain a significant challenge. In this research, the effect of strain relaxation on the growth rate of Ge1–y Sn y epilayers, with Sn concentration >11at.%, is investigated. It is successfully demonstrated that the growth rate slows down by ~55% due to strain relaxation after passing its critical thickness, which suggests a reduction in the incorporation of Ge into Ge1–y Sn y growing layers. Despite the increase in Sn concentration as a result of the decrease in the growth rate, it has been found that the Sn incorporation rate into Ge1–y Sn y growing layers has also decreased due to strain relaxation. Such valuable insights could offer a foundation for the development of innovative growth techniques aimed at achieving high-quality Ge1–y Sn y epilayers with tuned Sn concentration and strain relaxation.

All-dielectric double-layer honeycomb tunable metamaterial absorber with integrated gold nanoparticles

The optical regulation strategy of gold nanoparticles can significantly improve the performance of terahertz devices. We designed an all-dielectric double-layer honeycomb metamaterial absorber (MA) to demonstrate the broadband terahertz absorption characteristics in the presence or absence of gold nanoparticles. When it does not contain gold nanoparticles, MA exhibits a peak absorption efficiency of over 99% within the bandwidth range of ∼486 GHz. In particular, gold nanospheres (AuNPs), gold nanobipyramids (AuNBPs), and gold nanorods (AuNRs) are used to modulate the optical coupling effect of metamaterial absorbers, which improves their modulation performance. In the simulation, the effective medium theory (EMT) was applied to quantitatively calculate the optical response of a metamaterial absorber with an integrated gold nanoparticle equivalent gold layer. The integrated gold nanoparticle equivalent gold layer can achieve modulation enhancement of one order of magnitude. In the experiment, our process is compatible with CMOS technology, which may contribute to the development of terahertz detectors. In addition, the tunability and modulation enhancement characteristics demonstrated are beneficial for creating dynamic functional terahertz devices, such as THz modulators and switches.

Development of silicon drift detectors for synchrotron radiation sources

Synchrotron radiation facilities are essential interdisciplinary research platforms, with performance and efficiency closely tied to detector technology. To meet future requirements, especially the High Energy Photon Source (HEPS), we have conducted key technological research and development on single-element and array Silicon Drift Detectors (SDDs). The research and testing were conducted at the Platform of Advanced Photon Source Technology (PAPS). The test results indicate that the single-element SDD has achieved an energy resolution of 143 eV@5.9 keV (−35 °C), and the 20-unit array-SDD has reached an energy resolution of better than 300 eV@13.96 keV (−40 °C).

Review of Polarized Light‐Spin/Dipole Interactions: Fundamental Physics and Application in Circularly Polarized Detecting

AbstractCircularly polarized light (CPL) has attracted great attention due to its unique electromagnetic vector, which possesses potential practical applications in optical imaging, biometrics, and other interdisciplinary areas. At present, many materials with spontaneous CPL emitting have been extensively studied and reviewed for the generation of CPL. For the detection of CPL, mainly concentrate on the technical problems, that is, how to combine circularly polarized optical active materials with device structures to meet detection needs. Essentially, the resolution of CPL depends on the interaction between CPL and matter, Herein, the interactive modes including polarized light‐spin and light‐dipole (or charge) interactions in devices are summarized. Also, direct and indirect interactions of polarized light‐spin are presented. Meanwhile, the progress of light‐spin/dipole interaction dependence of CPL detectors is analyzed based on artificial structures of photoconductors, photodiodes, and photo field effect transistors. It is hoped that the review can broaden the bridge between the fundamental photon‐spin‐dipole interaction and CPL detectors with high performance, and then deepen the understanding of CPL detection and promote the development of CPL detectors.

Development of high performance micro-Resistive Groove detector

The Micro-Resistive Groove (μRGroove) is a single-stage Micro-Pattern Gaseous Detector (MPGD) with a groove amplification pattern. The resistive protection electrode is Diamond-Like Carbon (DLC), ensuring the detector achieves gas gain (≥104) and maintains good stability. The top copper layer of the groove is strip-shaped and can be grounded for 1D-strip readout. Therefore, only an additional 1D-strip is required to achieve 2D spatial resolution. Because the 2D readout is divided on both sides of the amplification structure, the induced charge-sharing effect is avoided, effectively increasing the induced signal amplitude, which is beneficial for applications of large-area tracking and cylindrical MPGD. In this study, we present the design and performance of the 10cm×10cmμRGroove prototype, which can achieve an effective gain of 2×104, an energy resolution of approximately 25%, a maximum detection efficiency close to 98%, and 2D spatial resolution better than 80μm. It also introduces the 50cm×50cm large-area μRGroove, which shows preliminary results with a detection efficiency >96% and 2D spatial resolution better than 100μm, meeting the normal requirements for large-area tracking detection. Finally, it discusses the progress of the low-mass cylindrical μRGroove, with the first prototype having an effective area of 13.1cm in diameter and 10cm in length. Its energy resolution is ∼26% measured by 55Fe and further beam tests being planned. This design is expected to become a practical solution for the inner tracker of the STCF.

Evaluation of the Multidimensional Enhanced Lateral Flow Immunoassay in Point-of-Care Nanosensors.

Point-of-care (POC) nanosensors with high screening efficiency show promise for user-friendly manipulation in the ever-increasing on-site analysis demand for illness diagnosis, environmental monitoring, and food safety. Currently, inspired by the merits of integrating advanced nanomaterials, molecular biology, machine learning, and artificial intelligence, lateral flow immunoassay (LFIA)-based POC nanosensors have been devoted to satisfying the commercial demands in terms of sensitivity, specificity, and practicality. Herein, we examine the use of multidimensional enhanced LFIA in various fields over the past two decades, focusing on introducing advanced nanomaterials to improve the acquisition capability of small order of magnitude targets through engineering transformations and emphasizing interdomain fusion to collaboratively address the inherent challenges in current commercial applications, such as multiplexing, development of detectors for quantitative analysis, more practical on-site monitoring, and sensitivity enhancement. Specifically, this comprehensive review encompasses the latest advances in comprehending LFIA with an alternative signal transduction pattern, aiming to achieve rapid, ultrasensitive, and "sample-to-answer" available options with progressive applications for POC nanosensors. In summary, through the cross-collaboration development of disciplines, LFIA has the potential to break the barriers toward commercialization and achieve laboratory-level POC nanosensors, thus leading to the emergence of the next generation of LFIA.