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Abstract Direct X-ray detectors based on semiconductors have drawn great attention from researchers in the pursuing of higher imaging quality. However, many previous works focused on the optimization of detection performances but seldomly watch them in an overall view and analyze how they will influence the detective quantum efficiency (DQE) value. Here, we propose a numerical model which shows the quantitative relationship between DQE and the properties of X-ray detectors and electric circuits. Our results point out that pursuing high sensitivity only is meaningless. To reduce the medical X-ray dose by 80%, the requirement for X-ray sensitivity is only at a magnitude of 103 μCGy−1⋅cm−2. To achieve the DQE = 0.7 at X-ray sensitivity air from 1248 to 8171 μCGy−1 air⋅cm−2, the requirements on dark current density ranges from 10 to 100 nA⋅cm−2 and the fluctuation of current density should fall in 0.21 to 1.37 nA⋅cm−2. Graphical Abstract

As lead halide perovskite (LHP) semiconductors have shown tremendous promise in many application fields, and particularly made strong impact in the solar photovoltaic area, low dimensional quantum dot forms of these perovskites are showing the potential to make distinct marks in the fields of electronics, optoelectronics and photonics. The so-called perovskite quantum dots (PQDs) not only possess the most important features of LHP materials, i.e., the unusual high defect tolerance, but also demonstrate clear quantum size effects, along with exhibiting desirable optoelectronic properties such as near perfect photoluminescent quantum yield, multiple exciton generation and slow hot-carrier cooling. Here, we review the advantageous properties of these nanoscale perovskites and survey the prospects for diverse applications which include light-emitting devices, solar cells, photocatalysts, lasers, detectors and memristors, emphasizing the distinct superiorities as well as the challenges.

Analyzing the isotopic composition of cosmic rays (CRs) provides valuable insights into the galactic environment and helps refine existing propagation models. A particular interest is devoted to secondary-to-primary ratios of light isotopic components of CRs, the measurement of which can provide complementary information with respect to secondary-to-primary ratios like B/C. Given the complexity of the concurrent measurement of velocity and momentum required to differentiate isotopes of the same Z, a task typically accomplished using magnetic spectrometers, existing measurements of these ratios only effectively characterize the low-energy region (below 1 GeV/nucl). This study introduces a novel technique for isotopic distinction in CRs at high energies up to 100 GeV/nucl based on multiple scattering, which, combined with the proposed measurement of velocity, represent an interesting alternative to magnetic spectrometers. The performance of this technique was assessed through a dedicated simulation using the GEANT4 package, with specific emphasis on Z = 1 isotopes.

X-ray applications in imaging and beyond require efficient and optimal detectors. Energy separation, time loss, and manufacturing cost are among the features that led us to design a semiconductor detector. A low-gain avalanche diode (LGAD) with internal amplification allows, in a sufficient field, the internal propagation process by accelerating the carriers, the energy required for ionization, and the generation of secondary carriers to produce a better gain (higher signal-to-noise ratio) and also provide more time efficiency (in the range of nanoseconds). In this article, we simulate the LGAD silicon detector with Silvaco software by applying reverse bias voltage and radiation in the range of visible light to X-ray. Newton and Gummel's methods were used. In Newton's method, one of the mechanisms of radiation interaction with matter is considered variable and the rest are fixed. However, in Gummel's method, all mechanisms are solved simultaneously. In the X-ray wavelength range, the electron current in this detector is 10-4 amperes, and this current decreases with increasing energy. The dark current is 10-6 amperes. By applying visible light with 0.45-micrometer wavelength and 1 V/cm2 intensity, the detector current was obtained about 6.5×10-4 amperes. For 1.0×10-5 x-ray wavelength and 108 V/cm2 intensity, detector current was obtained about 3.5×10-4 amperes. Considering the quick response time of this detector and the current in the range of microamps, this detector is a suitable option for X-ray detection. Also, this detector shows superior performance in the visible light range.

Heterodyne detection based on interband cascade lasers (ICL) has been demonstrated in a wide range of different applications. However, it is still often limited to bulky tabletop systems using individual components such as dual laser setups, beam shaping elements, and discrete detectors. In this work, a versatile integrated ICL platform is investigated for tackling this issue. A RF-optimized, two-section ICL approach is employed, consisting of a short section typically used for efficient modulation of the cavity field and a long gain section. Such a laser is operated in reversed mode, with the entire Fabry–Pérot waveguide utilized as a semiconductor optical amplifier (SOA) and the electrically separated short section as detector. Furthermore, a racetrack cavity is introduced as on-chip single-mode reference generator. The field of the racetrack cavity is coupled into the SOA waveguide via an 800 nm gap. By external injection of a single mode ICL operating at the appropriate wavelength, a heterodyne beating between the on-chip reference and the injected signal can be observed on the integrated detector section of the SOA-detector.

Signal-to-noise ratio (SNR) analysis is a crucial component of optical system development for space remote sensing instruments. It serves as a quantitative assessment of the imaging quality and radiometric characteristics of space remote sensing. This paper utilizes the working principles and energy transfer principles of space remote sensing instruments to conduct SNR analysis and model development for commonly used spaceborne imagers, spaceborne imaging spectrometers, micro-optical remote sensing instruments, and point-source spatial targets. Additionally, the paper also examines the impact of the presence and width of slits in different space environments on the SNR of space remote sensing instruments. The calculation results indicate that the analysis of Signal-to-Noise Ratio (SNR) for different space remote sensing instruments requires the establishment of distinct SNR models. The magnitude of SNR primarily depends on crucial factors such as optical system quality, detector performance, and the space environment. Therefore, in the instrument design and data processing processes, it is essential to consider how to maximize SNR and establish more accurate corresponding SNR models to provide high-quality remote sensing data.

Single-photon detector is a device that can detect fragile light signals such as photons. Noise is one of the major problems of Single-Photon Avalanche Diode (SPAD) in quantum communication and other applications. The two main noises in SPAD are afterpulse and dark count rate. Afterpulse is one of the most critical challenges of SPAD type InGaAs at 1550 nm wavelength. Several solutions have been presented to reduce noise. One of the most important methods presented is based on pulse gate. Pulse gate is effective in noise reduction by limiting SPAD operation time. Self-differentiating and up-conversion methods are also used in telecommunication wavelength SPADs to reduce noise, which have high implementation costs due to their complex structure. In this paper, we present a novel method for SPAD noise reduction. In this method, the time of SPAD output pulses is recorded and checked. The processor detects photon pulses and noise with a new algorithm. Noise pulses are removed, and photon pulses remain. This method is suitable for some Quantum Key Distribution (QKD) protocols that are simultaneous sender and receiver. It cannot be used in LiDAR and other similar asynchronous applications. The noise reduction method presented in this paper can be used for all types of single photon detectors and at different wavelengths. Also, this method can be used simultaneously with other noise reduction methods and it greatly reduces the amount of noise.

The unique diffraction geometry of ESRF beamline ID06-LVP offers continuous static 2D or azimuthally resolving data collections over all accessible solid angles available to the tooling geometry. The system is built around a rotating custom-built Pilatus3 CdTe 900k-W detector from Dectris, in a configuration equivalent to three butted 300k devices. As a non-standard geometry, here the method of alignment, correction and subsequent integration for any data collected over all solid angles accessible, or over any azimuthal range contained therein, are provided and illustrated by parameterizing and extending existing pyFAI routines. At 1° integrated intervals, and typical distances (2.0 m), the system covers an area of near 2.5 m2 (100 Mpx square equivalent), to 0.65 Å resolution, at 53 keV from a total dataset of some 312 Mpx. Standard FWHMs of SRM660a LaB6 vary from 0.005° to 0.01°, depending on beam size, energy and sample dimensions, and are sampled at an elevated rate. The azimuthal range per static frame ranges from

Purpose: Monte Carlo simulations are crucial for calculating magnetic field correction factors kB for the dosimetry in external magnetic fields. As in Monte Carlo codes the charged particle transport is performed in straight condensed history (CH) steps, the curved trajectories of these particles in the presence of external magnetic fields can only be approximated. In this study, the charged particle transport in presence of a strong magnetic field B→ was investigated using the Fano cavity test. The test was performed in an ionization chamber and a diode detector, showing how the step size restrictions must be adjusted to perform a consistent charged particle transport within all geometrical regions. Methods: Monte Carlo simulations of the charged particle transport in a magnetic field of 1.5 T were performed using the EGSnrc code system including an additional EMF-macro for the transport of charged particle in electro-magnetic fields. Detailed models of an ionization chamber and a diode detector were placed in a water phantom and irradiated with a so called Fano source, which is a monoenergetic, isotropic electron source, where the number of emitted particles is proportional to the local density. Results: The results of the Fano cavity test strongly depend on the energy of charged particles and the density within the given geometry. By adjusting the maximal length of the charged particle steps, it was possible to calculate the deposited dose in the investigated regions with high accuracy (

In this paper, a probe for measuring radio-frequency electric fields in the environment is designed and presented. These electric fields consist of multi cellular technology (2G, 3G and 4G), including four bands: GSM900, GSM1800, 3G2100 and LTE2600. This device, called the MCT electric probe, is realized by three orthogonal antennas, in connection to frequency multiplexer circuits and detectors. The proposed antenna is a 3-D multi-branch monopole antenna, and these orthogonal antennas can receive the electric fields in all directions uniformly and isotopically. The proposed multiplexer can separate the received signals into four narrowband and has the ability to remove out-of-band signals. The detector is able to convert the fields received from the antenna and multiplexer sections to suitable DC voltages for amplifying and digital processing. Finally, the designed MCT electric probe is fabricated and tested. The measurements confirm the proper operation of the probe in terms of dynamic range, accuracy, sensitivity, and the linearity and isotropicity of the received electric fields.

Cosmic ray air showers are a phenomenon that can be observed on Earth when high-energy particles from outer space collide with the Earth’s atmosphere. These energetic particles in space are called primary cosmic rays and consist mainly of protons (about 89%), along with nuclei of helium (10%) and heavier nuclei (1%). Particles resulting from interactions in the atmosphere are called secondary cosmic rays. The composition of air showers in the atmosphere can include several high-energy particles such as mesons, electrons, muons, photons, and others, depending on the energy and type of the primary cosmic ray. Other than air, primary cosmic rays can also produce showers of particles when they interact with any type of matter; for instance, particle showers are also produced within the soil of planets without an atmosphere. In the same way, secondary cosmic particles can start showers of tertiary particles in any substance. In the 1930s, Bruno Rossi conducted an experiment to measure the energy loss of secondary cosmic rays passing through thin metal sheets. Surprisingly, he observed that as the thickness of the metal sheets increased, the number of particles emerging from the metal also increased. However, by adding more metal sheets, the number of particles eventually decreased. This was consistent with the expectation that cosmic rays were interacting with the atoms in the metals and losing energy to produce multiple secondary particles. In this paper, we describe a new–old approach for measuring particle showers in water using a cosmic ray telescope and Rossi’s method. Our instrument consists of four Geiger–Müller tubes (GMT) arranged to detect muons and particle showers. GMT sensors are highly sensitive devices capable of detecting electrons and gamma rays with energies ranging from a few tens of keV up to several tens of MeV. Since Rossi studied the effects caused by cosmic rays as they pass through metals, we wondered if the same process could also happen in water. We present results from a series of experiments conducted with this instrument, demonstrating its ability to detect and measure particle showers produced by the interaction of cosmic rays in water with good confidence. To the best of our knowledge, this experiment has never been conducted before. Our approach offers a low-cost and easy-to-use alternative to more sophisticated cosmic ray detectors, making it accessible to a wider range of researchers and students.

Visible Light Communication (VLC) has become an effective underwater communication technology due to its advantages such as fast transmission speed and strong confidentiality. When light propagates underwater, it is prone to scattering, resulting in a decrease in the energy of light propagation with the increase of transmission distance. Therefore, improving the responsiveness of the receiving end is the key technology to achieve underwater VLC. This article first designs a new holographic waveguide focusing system for the front end of the detector, which can effectively improve the signal-to-noise ratio of underwater detectors. Then, we construct a low-cost antimony sulfide thin film detector with weak light detection capability. Based on the built VLC system, the experimental results show that the dark current of the receiver detector is only 10-7 A/cm2, with a 3 dB bandwidth of 220 kHz, a response of 0.2 A/W, and an external quantum efficiency of over 70% in the blue green light band. Therefore, the new antimony sulfide thin film detector combined with a holographic waveguide focusing system can achieve weak light detection of visible light, making it a very effective underwater visible light receiving system.

In our previous study, we proposed an integrated PG-PET-based imaging method to increase the prediction accuracy for patient dose distributions. The purpose of the present study is to experimentally validate the feasibility of the PG-PET system. Based on the detector geometry optimized in the previous study, we constructed a dual-head PG-PET system consisting of a 16 × 16 GAGG scintillator and KETEK SiPM arrays, BaSO4 reflectors, and an 8 × 8 parallel-hole tungsten collimator. The performance of this system as equipped with a proof of principle, we measured the PG and positron emission (PE) distributions from a 3 × 6 × 10 cm3 PMMA phantom for a 45 MeV proton beam. The measured depth was about 17 mm and the expected depth was 16 mm in the computation simulation under the same conditions as the measurements. In the comparison result, we can find a 1 mm difference between computation simulation and measurement. In this study, our results show the feasibility of the PG-PET system for in-vivo range verification. However, further study should be followed with the consideration of the typical measurement conditions in the clinic application.

Contamination of food and water with radioactive substances is a serious health problem. There are several methods to detect and measure radioactive materials, some of which have been developed in recent years. This paper aims to discuss the methods of detecting and measuring radioactive substances in food and water. The principles and the advantages and disadvantages of each method have been discussed. The results showed that some of these methods, such as spectrometry γ-ray high purity germanium, portable radon gas surveyor SILENA, RAD7, and inductively coupled plasma mass spectrometry, have a higher sensitivity for detection and measurement. Also, the spectrometry γ-ray high purity germanium method has attracted more attention than other methods because it can measure a wide range of radionuclides with high resolution.

Along with the arrival of the digital era, promoting the high-quality development of rural tourism with a digital economy has become a new driving force and goal. This study examines the mechanism of digital technology to promote the high-quality development of rural tourism based on the perspective of stakeholders in rural tourism development. After selecting the evaluation indexes of digital technology to promote the high-quality development of rural tourism, the weights of the indexes are determined, and the level of digital technology to promote the high-quality development of rural tourism is measured by using the fuzzy comprehensive evaluation method in a rural tourism site as an example. The driving force factors of digital technology to promote the high-quality development of rural tourism are selected from both internal and external dimensions, and the driving force of digital technology to promote the high-quality development of rural tourism is analyzed by using geographic detectors for divergence and factor detection and interaction detection. The results can be obtained that the overall development of the sample rural tourism sites is located between average and better, with a comprehensive score of 6.842, especially in its cultural digitization and environmental monitoring digitization, with scores greater than 6. Digital technology to promote the high-quality development of rural tourism is subject to the joint effect of a variety of factors. The number of Internet broadband access ports is the core factor, and the factor contribution rates are all above 0.8. The research on effects and driving forces in this paper is of great significance in achieving high-quality development of rural tourism.

High intakes of histamine are poisonous. Hence, determining histamine levels in fisheries and processed products is essential to food quality. Several colorimetric sensors based on gold nanoparticles have shown exemplary performance in detecting the presence of histamine in samples. The modified AuNPs by MnO2 were used as a reagent in histamine analysis by UV–Vis spectrophotometry. Using a seed-mediated growth method, modified Au–MnO2 nanostructures were synthesized from citrate-coated AuNPs and KMnO4. The Au–MnO2 nanostructure synthesis process produced a yellow-green solution, which produced a crystalline solid with a particle size

Uncooled bolometric type thermal detectors, combined into a matrix and placed into a focal plane array have the following characteristics: low cost, operation at room temperature, compatibility with the silicon CMOS technology, and high detecting performance; therefore recently it became a hot spot in infrared or terahertz detection field. The performance of uncooled infrared focal plane detector arrays depends on the optimization of critical parameters which are determined by geometrical design and the electrical, optical, and thermal physical properties of the detector materials. We report the study of a fabrication process and characterization of two (2D) dimensional arrays of uncooled microbolometers based on silicon (α-Si) thermo-sensing films. Because these arrays substantially reduce sensor size, they are becoming the preferred format for most modern applications.

The X-ray Integral Field Unit (X-IFU) is one of the two focal plane detectors of Athena, a large-class high energy astrophysics space mission approved by ESA in the Cosmic Vision 2015–2025 Science Program. The X-IFU consists of a large array of transition edge sensor micro-calorimeters that operate at ~100 mK inside a sophisticated cryostat. To prevent molecular contamination and to minimize photon shot noise on the sensitive X-IFU cryogenic detector array, a set of thermal filters (THFs) operating at different temperatures are needed. Since contamination already occurs below 300 K, the outer and more exposed THF must be kept at a higher temperature. To meet the low energy effective area requirements, the THFs are to be made of a thin polyimide film (45 nm) coated in aluminum (30 nm) and supported by a metallic mesh. Due to the small thickness and the low thermal conductance of the material, the membranes are prone to developing a radial temperature gradient due to radiative coupling with the environment. Considering the fragility of the membrane and the high reflectivity in IR energy domain, temperature measurements are difficult. In this work, a parametric numerical study is performed to retrieve the radial temperature profile of the larger and outer THF of the Athena X-IFU using a Finite Element Model approach. The effects on the radial temperature profile of different design parameters and boundary conditions are considered: (i) the mesh design and material, (ii) the plating material, (iii) the addition of a thick Y-cross applied over the mesh, (iv) an active heating heat flux injected on the center and (v) a Joule heating of the mesh. The outcomes of this study have guided the choice of the baseline strategy for the heating of the Athena X-IFU THFs, fulfilling the stringent thermal specifications of the instrument.

Purpose: In this study an evaluation of the imaging performance of an electronic portal imaging device (EPID) is presented. The evaluation performed employing the QC-3V image quality phantom. Methods: An EPID system of a 6 MV LINAC, was used to obtain images of a QC-3V EPID phantom. The X-ray source to phantom distance was 100 cm and the field size was 15x15 cm2. The irradiation conditions comprised Dose Rates (DR) of 200, 400 and 600 for a 2 MU–100 MU range. The Contrast Transfer Function (CTF), the Noise Power Spectrum (NPS), the Normalized Noise Power Spectrum (NNPS) and the Contrast-to-Noise Ratio (CNR) were studied. In addition, an alternative factor showing a frequency related output signal-to-noise ratio (SNR), the Signal-to-Noise-Frequency Response (SNFR), has been introduced. SNFR is a comprehensive quality index, easily determined in clinical environment. Results: The CTF curves were found comparable to each other. The lowest values were measured at 2 MU and 200 MU/min. Concerning the NPS and NNPS graphs it was found that the values decrease up to approximately 0.3 lp/mm and demonstrate a white noise shape afterwards. SNFR values were found reducing with spatial frequency. Highest CNR were found between the region 7 and 11 of the phantom. Conclusions: The influence of MU and DR on EPID performance were investigated. Image quality was assessed using the QC-3V phantom. The presented results can lead to image quality amelioration and act supportively to current image quality control routine protocols.

An inverse T shape structure, consisting of two perpendicular cavities coupled with a bus-waveguide truncated by a block, has been proposed and investigated numerically. Multi Fano resonance, attributing to the interaction of one continuous and two discrete states, can be observed in transmission spectrum. The numerical results are demonstrated by the coupled mode theory. At the same time, it is feasible to produce multi Fano resonance which derive from the splitting of different order modes by adjusting D value, which has been well explained theoretically. When the inverse T shape is filled with Polyhexamethylene biguanide (PHMB), a perfect absorbing coating to monitor the CO2 concentration, the structure can be served as a high sensitivity CO2 detector, whose sensitivity can up to 303 pm/ppm. In addition, the sensitivity of this proposed structure is ∼2.23 times higher than the previous work. The proposed structure has the advantages of simple, compact and easy fabrication. The results represented in this study may have potential applications in sensing and CO2 detector, which can provide the guideline to design other types of gas detector.

Fire detectors present very important elements in fire protection systems. Their correct and precise installation present very important task in fire protection. Very often, there are problems related to the number of installed fire detectors and their locations and arrangement in the object. There are several standards that deal with fire detectors installations and arrangement. In some cases, these standards have similar rules, but in others, they have different rules. Also, some of standards have very detail rules and explanations about fire detectors installation and arrangement in some cases, while other standards are not very detail or they don't deal with that problems at all. One of the very interested cases, marked in all standards as a special case for installation of fire detectors is a stairs case. This paper was written to show rules in different valid standards related to installation and arrangement of fire detectors in the case of stairs and computer simulation of fire detectors at stairs.

The key task of computer vision is the recognition of visual objects in the analysed image. This paper proposes a method of searching for objects in an image, based on the identification of a cluster representation of the query descriptions and the current image of the window with the calculation of the relevance measure. The implementation of a cluster representation significantly increases the speed of identification or classification of visual objects while maintaining a sufficient level of accuracy. Based on the development of models for the analysis and processing of a set of descriptors of keypoints, we have obtained an effective method for the identification of visual objects. A comparative experiment with the traditional method has been conducted, where a linear search for the nearest descriptor was implemented for identification without using a cluster representation of the description. In the experiment, a speed gain for the developed method has been obtained in comparison with the traditional one by approximately 5.2 times with the same level of accuracy. The method can be used in applied tasks where the time of object identification is critical. The developed method can be applied to search for several objects of different classes. The effectiveness of the method can be increased by varying the values of its parameters and adapting to the characteristics of the data.

The evolution of next-generation cellular networks is aimed at creating faster, more reliable solutions. Both the next-generation 6G network and the metaverse require high transmission speeds. Visible light communication (VLC) is deemed an important ancillary technology to wireless communication. It has shown potential for a wide range of applications in next-generation communication. Micro light-emitting diodes (μLEDs) are ideal light sources for high-speed VLC, owing to their high modulation bandwidths. In this review, an overview of μLEDs for VLC is presented. Methods to improve the modulation bandwidth are discussed in terms of epitaxy optimization, crystal orientation, and active region structure. Moreover, electroluminescent white LEDs, photoluminescent white LEDs based on phosphor or quantum-dot color conversion, and μLED-based detectors for VLC are introduced. Finally, the latest high-speed VLC applications and the application prospects of VLC in 6G are introduced, including underwater VLC and artificial intelligence-based VLC systems.

The ongoing Covid-19 pandemics showed the need for the effective decontamination of environment and surfaces. One of the options could be the use of gas ozone. Ozone has been well known for its disinfection properties, which were in the past used to decontaminate water. In this article, we present a development of an easy-made and ready-to-use portable detector of ozone, which could be used to easily detect ozone in the environment. In addition, we studied degradation impact of ozone on different materials, which normally occur in households or at working places. Ozone is well detectable and does not cause any damage to materials at concentrations needed for decontamination of the environment.

The decontamination of structures with radioactive substances is one of the most important areas of environmental chemistry. In this study, an intelligent polymeric coating containing a Br-PADAP detector was made to identify and remove the uranyl nitrate contaminant (UO2(NO3)2.6H2O). In this study, the effect of pH was investigated for the first time. Also, the parameters of different substrates, detector concentration, contaminant drying temperature, coating drying temperature, and mechanical properties of the contaminant adsorption were investigated. The results of an evaluation of FT-IR, TGA, and liquid scintillation tests well prove the presence of uranium ions in the coating. The polymer coating containing the EDTA and Br-PADAP detector becomes purple to brown by absorbing a contaminant solution containing uranium ions. Quantitative evaluation based on MATLAB software image processing methods also shows a color change. Decontamination factors (DFs) in this coating were shown to be above 97% at 2000 ppm, and higher than in previous studies. The polymer solution was obtained with optimal formulation and flexible film.

The purpose of this comprehensive research is to observe the impact of scintillator crystal type on entire detection process. For this aim, MCNPX (version 2.6.0) is used for designing of a physical plastic scintillation detector available in our laboratory. The modelled detector structure is validated using previous studies in the literature. Next, different types of plastic scintillation crystals were assessed in the same geometry. Several fundamental detector properties are determined for six different plastic scintillation crystals. Additionally, the deposited energy quantities were computed using the MCNPX code. Although six scintillation crystals have comparable compositions, the findings clearly indicate that the crystal composed of PVT 80% + PPO 20% has superior counting and detecting characteristics when compared to the other crystals investigated. Moreover, it is observed that the highest deposited energy amount, which is a result of the highest collision number in the crystal volume, corresponds to a PVT 80% + PPO 20% crystal. Despite the fact that plastic detector crystals have similar chemical structures, this study found that performing advanced Monte Carlo simulations on the detection discrepancies within the structures can aid in the development of the most effective spectroscopy procedures by ensuring maximum efficiency prior to and during use.

PET (Positron-emission tomography) is used to determine physiological and metabolic functions in the body. Monte Carlo simulation is an important part of PET imaging, and the Particle Heavy Ion Transport code System (PHITS) is a simulation platform that can be used to perform Monte Carlo simulations. This study uses a Monte Carlo simulation based on PHITS to determine the range of gamma absorption with an energy of 511 keV in a scintillation detector crystal material. The gamma absorption range determines the effective crystal length in the PET modality. The simulation process is carried out by shooting Gamma at various types of materials, which are the materials used in PET scintillation crystals. The materials used in this simulation are NaI (Sodium Iodide), BaF2 (Barium Florida), BGO (Bismuth Germanate), and GSO (Gadolinium Oxyorthosilicate), considering their atomic number and crystal density. The crystal material is capable of absorbing gamma radiation with an energy of 511 keV with detailed crystal lengths for each NaI crystal of 0.26 cm; 0.25 cm BaF2 crystals; 0.1cm BGO crystals; and 0.18 cm GSO crystals. The crystal length from this simulation is smaller than the commercially available crystal length (range 1-3 cm). Based on the crystal length data, the most effective crystal for absorbing gamma radiation is the BGO crystal.

Metal halide perovskite (MHP) detectors are highly esteemed for their outstanding photoelectric properties and versatility in applications. However, they are unfortunately prone to degradation, which constitutes a significant barrier to their sustained performance. This review meticulously delves into the causes leading to their instability, predominantly attributable to factors such as humidity, temperature, and electric fields and, notably, to various radiation factors such as X-rays, γ-rays, electron beams, and proton beams. Furthermore, it outlines recent advancements in strategies aimed at mitigating these detrimental effects, emphasizing breakthroughs in composition engineering, heterostructure construction, and encapsulation methodologies. At last, this review underscores the needs for future improvements in theoretical studies, material design, and standard testing protocols. In the pursuit of optimizing the chemical stability of MHP detectors, collaborative efforts are in an imperative need. In this way, broad industrial applications of MHP detectors could be achieved.

CubeSats have emerged as cost-effective platforms for biological research in low Earth orbit (LEO). However, they have traditionally been limited to optical absorbance sensors for studying microbial growth. This work has made improvements to the sensing capabilities of these small satellites by incorporating electrochemical ion-selective pH and pNa sensors with optical absorbance sensors to enrich biological experimentation and greatly expand the capabilities of these payloads. We have designed, built, and tested a multi-modal multi-array electrochemical-optical sensor module and its ancillary systems, including a fluidic card and an on-board payload computer with custom firmware. Laboratory tests showed that the module could endure high flow rates (1 mL/min) without leakage, and the 27-well, 81-electrode sensor card accurately detected pH (71.0 mV/pH), sodium ion concentration (75.2 mV/pNa), and absorbance (0.067 AU), with the sensors demonstrating precise linear responses (R2 ≈ 0.99) in various test solutions. The successful development and integration of this technology conclude that CubeSat bio-payloads are now poised for more complex and detailed investigations of biological phenomena in space, marking a significant enhancement of small-satellite research capabilities.

Accurate observation of two or more particles within a very narrow time window has always been a challenge in modern physics. It creates the possibility of correlation experiments, such as the ground-breaking Hanbury Brown–Twiss experiment, leading to new physical insights. For low-energy electrons, one possibility is to use a Microchannel plate with subsequent delay lines for the readout of the incident particle hits, a setup called a Delay Line Detector. The spatial and temporal coordinates of more than one particle can be fully reconstructed outside a region called the dead radius. For interesting events, where two electrons are close in space and time, the determination of the individual positions of the electrons requires elaborate peak finding algorithms. While classical methods work well with single particle hits, they fail to identify and reconstruct events caused by multiple nearby particles. To address this challenge, we present a new spatiotemporal machine learning model to identify and reconstruct the position and time of such multi-hit particle signals. This model achieves a much better resolution for nearby particle hits compared to the classical approach, removing some of the artifacts and reducing the dead radius a factor of eight. We show that machine learning models can be effective in improving the spatiotemporal performance of delay line detectors.

Terrorist organizations have compelled security authorities of every nation to make an increasingly significant commitment toward mitigating the risk of mass casualties and severe financial and property damages. As a result, various security measures have been implemented, including the use of advanced equipment and an uptick in intelligence activities. One of the most effective tools that has yielded outstanding results is the use of explosive detection dogs (EDDs). The nature of EDDs demands a high level of sensitivity given the inherent danger and severity of real threat situations that may involve the risk of explosion. Moreover, the operating procedures for EDDs are unique and distinguishable from other forms of detection. We conducted a review to ensure a comprehensive understanding of the subject, highlighting the EDDs’ personality profile, selection, training methods, performance, and employment, incorporating insights from diverse fields, conducting an analysis, and presenting a perspective on using EDDs to prevent explosion threats.

The main object of this research was to develop a security system to evaluate the intrusion into an object through a glass pane. More specifically, this study deals with sensing and evaluating signals from a contact glass-break detector, which is part of an intruder alarm system. Each alarm detector in an alarm system must accomplish certain security level requirements that strictly describe the requirements for the area of use and the detector’s reliability. To date, no contact glass-break detector has been developed and fully tested to meet the stringent requirements of the highest security level. A contact glass-break detector was developed whose main part is an accelerometer that transmits signals from the glass pane. These signals were evaluated according to the developed methodology. It was verified that the proposed system can distinguish at the highest security level between false alarms and situations where the building has been intruded.

Many factors cause people to be reluctant to apply solar panel technology as a source of renewable electrical energy, one of which is the efficiency level of solar panels which is still very low because the position of solar panels is generally facing in one direction. In this study, we designed a tool that can automatically drive the solar panel motor according to the comparison value obtained from the LDR sensor. There are four LDR sensors for comparison that are used as a reference tool to move towards the brightest light intensity. From this solar panel, the power will be stored in the battery which at the same time drives the motor so that the rays obtained are more optimal and faster for charging the battery. From the results of the research conducted, the energy efficiency in a day is 9 percent from normal conditions without using optimization. It is hoped that this tool can help the community to use alternative renewable energy sources that are more effective and efficient.

Background. Reliable operation of in-core neutron detectors improves the quality of measurement data processing and make fields of the neutron and power distributions in the nuclear reactor core more efficient. Materials and methods. The article discusses a new method for monitoring the technical condition of self-powered neutron detector (SPND) that is used to measure neutron flux in the nuclear reactor core. The method is based on the measurement of current values of the detector measuring circuit under steady and dynamic conditions. To monitor the state of this neutron detector, it is proposed to determine not only the insulation resistance of the measuring cable, as it is done in traditional methods, but also the generating capacity of the detector emitter. In addition to the given diagnostic parameters, a new diagnostic feature of the controlled object – capacitance of the measuring circuit of the reactor – has been is introduced in this article. Results and conclusions. Determination of the generating capacity of SPND emitter significantly (by 3–4 orders of magnitude) extends the operating range of the detector by the permissible insulation resistance value (less than 106 Ohms). At the same time, we obtain a new method to estimate the degree of electron emitter burnup caused by neutron flux and to monitor the technical condition of detector by the magnitude of its sensitivity to this flux, which increases the reliability of SPND. Determining the capacitance of the measuring cable of the electrical circuit allows you to properly consider this value when measuring the current signal of the activation detector in order to find the reactor neutron flux under the transient modes of operation.

COVID-19 has created a global serious health hazard with far-reaching consequences for society, our perceptions of the world, and how we live our daily lives. As a result, the World Health Organization recommended the use of face masks and social isolation to help reduce the rising number of infections. However, subsequent research has revealed that face masks alone can be ineffective, particularly in crowded settings or hospitals. Face shields can also be used in addition or as an alternative for face masks because they are indefinitely reusable and can be washed with soap and water or standard disinfectants. Because most detectors for fighting COVID-19 only focus on the face mask alone, we proposed a transfer learning model by fine-tuning the pre-trained MobilenetV2 architecture, to detect, recognize, and distinguish faces with shield, mask, and those without either. This study applied a standard image recognition pipeline, which is comparable to that used by most traditional recognition programs. In doing this, we first downloaded and scrapped images from search engines to form our dataset, we then pre-processed the images by the application of image augmentation to address the limited availability of the dataset for a better training and validation. After which a multi-class detection system was accomplished. The results of the study achieved 98 percent accuracy on the validated dataset. It is therefore recommended that this model can be improved to capture all forms of face covering and be integrated into CCTV cameras for its detection in important places like hospitals.

The main characteristics of airborne micro/nanoparticles, their impact on human health and air quality standards are presented. International standards classify microparticles by size (PM10, PM2.5, PM1, UFP), establish maximum allowable concentrations and control methods. Particular attention is paid to carbonand virus-containing microparticles control. To monitor the air environment in enclosed spaces and in transport, the portable sensors of micro-, nanoparticles are required with the ability to classify them by size and electrophysical characteristics.Detection of microparticles includes the sorting of particles entering the sensor by size and material type, subsequent actual detection of particles of the same kind, with subsequent classification by size, electrical and morphological characteristics. Separation of nanoand microparticles by size before detection improves the sensitivity and selectivity of the detector both in size and material. The virtual impactor and dielectrophoresis method are considered for integration in a Lab-on-Chip type sensor. Detection of microparticles is performed by separating the dispersed phase from the aerosol followed by the analysis, or directly in the air flow. The classification of detection methods according to speed and functionality is given. Among the methods allowing detection of micrometer and submicrometer size particles, the most suitable for miniaturization and serial production of Lab-on-Chip sensors are the multi-wavelength photoelectric, MEMS, and capacitor elements.The microelectromechanics, microfluidics and microoptics technologies make it possible to create portable sensor systems of the Lab-on-Chip type to detect particulates matter of micrometer and submicrometer size. A micro-, nanoparticles detector prototype based on alumina technology using MEMS elements for a compact Lab-on-Chip type sensor is presented. The proposed design for multifunctional portable detector of airborne micro/nanoparticles is prospective for industry, transport, medicine, public and residential buildings applications.

Composite scintillation screens on a base of Gd1.2Y1.8Ga2.5Al2.5O12:Ce (GYAGG) scintillator have been evaluated for neutron detection. Besides the powdered scintillator, the composite includes 6LiF particles; both are merged with a binder and deposited onto the light-reflecting aluminum substrate. Results obtained demonstrates that screens are suitable for use with a silicon photomultiplier readout to create a prospective solution for a compact and low-cost thermal neutron sensor. Composite GYAGG/6LiF scintillation screen shows a pretty matched sensitivity and γ-background rejection with a widely used ZnS/6LiF screens however, possesses forty times faster response.

Fire presents almost everyday occurrence in people's life and work. The fight against fire must be fast and effective because consequences can be inconceivable, in the sense of human lives and material properties. Fire can occur everywhere: in the residential building, in factory, in hospital, in parking garage, in market, in school, anywhere where are people and their activities. Fire also can occur as natural disaster. One of ways how to fight against fire is to detect fire at early stage, as fast as possible. For that purpose, fire detectors are designed. This paper was written to show usage of line heat detectors in fire protection, their arrangement in objects related to different valid standards and computer simulation of line heat detectors in parking garages.

As we look forward to the next generation of hyperspectral infrared (IR) atmospheric sounders, grating spectrometers hold promise for improved performance (e.g., horizontal and spectral resolutions) and more rapid revisit while reducing the size and complexity of the instrument. We briefly revisit the technology used in the Atmospheric Infrared Sounder (AIRS), recognizing that it was developed in the 1990’s and has matured key technologies in the areas of IR detectors, optical coatings, gratings, and cryocoolers. AIRS has been an unqualified success not only as a science and operational mission but also as a technology demonstration of the reliability and simplicity of grating spectrometer IR sounding instruments. Advancements in focal plane arrays (FPAs) have enabled a new class of grating spectrometer IR sounders that offer more spectral channels on a single FPA, mitigating some of the issues seen in AIRS that used linear arrays. These improvements have been manifested in the CubeSat Infrared Atmospheric Sounder (CIRAS) brassboard instrument, developed at the California Institute of Technology Jet Propulsion Laboratory with industry partner Ball Aerospace. Further enhancements beyond those used in CIRAS enable the development of a new class of instruments with a very long-wavelength infrared response and a very high spatial resolution (

The frequency-modulated continuous-wave (FMCW) radar is generally applied in ground target detecting devices mounted on small shells or projectiles because of its compact size. However, the FMCW radar often produces false alarms when detecting ground targets surrounded by heavy clutter. To overcome this problem, this paper proposes a ground target detection system based on both the miniaturized FMCW radar and the total power radiometer (TPR), consisting of the common millimeter-wave (MMW) front ends and an antenna. However, its intermediate frequency (IF) parts are separated using different frequency bands to miniaturize the entire system. The minimum detectable temperature (MDT) increases and the sensitivity is thus degraded because the TPR for the hybrid sensor inevitably includes an undesirable transmitter section owing to the widespread usage of the front ends with the radar. The proposed system employs optimization of the physical path delay and duplexing the IF band for the TPR and FMCW radar to improve the sensitivity of the TPR in the proposed hybrid sensors and reduce the system noise. The system includes a matching circuit and a voltage doubler to improve the sensitivity of the detector. Therefore, the MDT of TPR in the proposed hybrid system can be reduced to 47.5 K from 734.6 K in the initial design. The drop test demonstrates that the proposed hybrid sensor can reduce false alarms when compared to using either the FMCW radar or only the TPR.

Smoke detectors as fire detectors present the most frequently used fire detectors from all other detectors. Their great appliance is enabled because smoke presents the consequence of f almost every fire. The realisation of these detectors can be in the form of point smoke detectors, in the form of linear smoke detectors and in the form of special smoke detectors. Generally, there are rules for arrangement of these detectors related to valid standards. Standards in some cases can be similar, but in some cases, there can be some differences between standards. This is specially noted for smoke detectors arrangement in special cases. One of such case is room with girts. Girts can be different located in room and can have functional or aesthetic purpose. This paper was written to present smoke detectors arrangement in room with girts, with different room`s height, related to British standard BS 5839-1 and test all potential cases using FDS simulator.

Covid-19 has hit many countries in the world, including Indonesia. The rapid and deadly spread of Covid-19 reached Indonesia in early 2020. This pandemic of course had a detrimental impact on the Indonesian people in terms of health, economy, education and others. The Indonesian government certainly does not remain silent, the government is aggressively making efforts to break the Covid-19 chain in various ways, one of the efforts made is to continuously inform about the health protocols recommended by the government to prevent transmission. The Indonesian Ministry of Health (in Mardhia et al., 2020) Efforts that can be made in the prevention phase by each individual include: Wearing a mask, Wearing gloves, Using hand sanitizer/disinfectant, Washing hands with soap, Avoiding touching the face, Avoid shaking hands, Avoid gatherings or long queues, Avoid touching objects/object surfaces in public areas, Avoid taking public transportation, Maintain a distance of at least two meters from other people when outside the house, and If you show symptoms of illness, immediately notify the people around. Even though they have been informed about the prevention of Covid-19, the public tends to be negligent in implementing health protocols, one of which is the application of Social Distancing. Therefore, this study will create a distance detector using the YOLOv3 algorithm as one of the detection objects for the implementation of community activity restrictions

Abstract The detection of ionizing radiation such as X‐ray, γ‐ray, α‐particle, and neutrons has been widely required in medical and industrial areas. Perovskite semiconductor detectors are arousing widespread interest and achieving significant progresses in this area. Unique material strengths, such as large attenuation coefficient, defect tolerant nature, balanced carrier mobilities, and feasible preparation techniques, make perovskite semiconductor detector a strong competitor to existing commercial products. Inspired by the booming development of this area, we review the current achievements of ionizing radiation detection with perovskite semiconductors. Firstly, a comprehensive summary of the device preparation techniques is provided, followed by a profound discussion of the detector physics. Then, the broad applications of perovskite semiconductor detectors are illustrated. Finally, we give an outlook of the current challenges pending to be tackled for commercialized applications. We believe the perovskite semiconductor detectors will be new blood to the current ionizing radiation detection market.

Global Navigation Satellite Systems or GNSS is a space technology that has become an essential element nowadays for positioning, navigation & timing (PNT) with wide range of applications in many civilian sectors as well as across military. The reliability, accuracy and availability of GNSS are highly important especially for critical and precise positioning applications. However, the signals from space are weak and it can be easily blocked, disrupted or compromised by several other threats including intentional and unintentional interferences or jamming. GPS jammer is widely available off the shelf with an affordable price and capable of interfering the GPS signal, and many authorities worldwide have raised concerns and a lot of efforts and research have been put in place to reduce and mitigate the threats. In Malaysia, understanding and countering threats to GNSS/GPS based applications will be a new and unfamiliar discipline for public and organizations. This study intended to provide an overview of the GNSS interferences environment in a local study area, in terms of interference type and the number of activity pattern that were detected. A system called Detector V1 has been used in this study. The result showed thatsignificant interference cases happened in the study area and some of the high power interferences may impact GNSS tracking and precision of the positioning output. The role objective of having this done is to create a public awareness regarding the threat of GNSS interferences to the local users. The content also includes the proposed initiative to overcome the issue.

The article presents the results of regional surveys of bats in 2010–2020 in places planned for the construction of wind farms. With the use of modern ultrasonic detectors, computer programs and an electronic library of voices, 15 species were found in the Ukrainian Azov Region. Their highest diversity (11–13 species) was revealed in places of intensive migration. First of all, these are the sites Armyansk, Chaplynka, and Askania-Nova, which are located between the Dnieper valley and the Crimean Peninsula. Probably, in this area, bats migrating from the northern and north-eastern regions cross the land and join those moving along the Azov coast. The movement of a significant number of animals is noticeable in the west of the Molochna River. A relatively large variety of bats occurs near the sites Botiyevo, Orlivka, and Primorsk, located directly on the northern shore of the Sea of Azov, along which the migratory movements of bats are particularly strong. During winter, with limited research in this period, 8 species were found, whereas 13 species during spring and autumn migrations and 11 species in summer. The almost complete transformation of the steppe into agrocoenoses bordered by forest belts and irrigation canals undoubtedly affected bats in addition to global warming. In recent years, in all places of the Ukrainian Azov Region, there has been a decline in the number of the common pipistrelle (Pipistrellus pipistrellus) and serotine bats (Eptesicus serotinus), and an increase in the abundance of the noctule bat (Nyctalus noctula), Kuhl's pipistrelle (Pipistrellus kuhlii), Nathusius' pipistrelle (Pipistrellus nathusii), and parti-coloured bat (Vespertilio murinus). In all seasons, the least common species were the brown long-eared bat (Plecotus auritus), Daubenton's bat (Myotis daubentonii), greater noctule (Nyctalus lasiopterus), lesser noctule (Nyctalus leisleri), Savi's pipistrelle (Hypsugo savii), and western barbastelle (Barbastella barbastellus).

In order to carry out the theoretical research and the structural design of speed control unit for the composite pipeline detector with diameter of 813 mm, a calculation model concerning the deceleration capability of speed control unit was established according to the theory of computational fluid dynamics, and the deceleration capability of the speed control unit under different working conditions was simulated and analyzed, which was verified by the pull test of the composite pipeline detector with diameter of 813 mm. The results show that the designed speed control unit of composite pipeline detector with diameter of 813 mm is capable of reducing the speed at 4.7 m/s as required by the design indicators within the pressure range of (3.4-7.4 MPa) and the flow rate of (8-9 m/s) of medium. Generally, the structural design method of the detector speed control unit combining the simulation analysis based on the theory of computational fluid dynamics and the experimental test is of great guiding significance for improving the structural research, development and design of the detector speed control unit and promoting the progress of the detection technologies of oil and gas pipelines.

The development of technology in an increasingly sophisticated industrial era is evidenced by the presence of modern equipment produced to speed up and simplify a job. In Advertising currently has no filtering about the age of its readers. Based on this background this study built a system for billboard display (advertising) based on age. For the method used using the method of artificial neural networks. For testing the tool uses distance parameters based on objects that are indexed with two categories namely adults and children. For the test results using 4 objects of people with a distance of 1 meter to 5 meters per object obtained the results detected each adult and small children distanced 1 meter to 3 meters in a distance of 4 meters to 5 meters undetected with an accuracy of 80%.

In order to reduce the partial abrasion of the cup of pig and detector in pigging and detection under some special conditions, the causes for partial abrasion of cup were analyzed in depth, a structural design scheme of composite wear-resistant cup for oil and gas pipeline with diameter of 355.6 mm was proposed, and the adaptability and sealing performance of the composite wear-resistant cup in pipeline with different wall thickness was verified by the finite element simulation analysis. The analysis results show that the universal ball on the outer edge of the cup can effectively reduce the contact area between the cup lip and the pipe wall, and share the positive pressure and contact stress on the cup lip under the premise of guaranteeing its inherent sealing performance during the contact between the composite cup structure and the pipeline with different wall thickness, which shows that the structural design of the composite wear-resistant cup is rational and feasible to certain extent, capable of effectively reducing the wear of the cup lip and the partial wear of the cup. The structural design and sealing performance analysis verification of the composite wear-resistant cup are of important practical significance to enrich the domestic design concept of cup for pig and detector and to improve the structural design of pig and detector.

One common computer vision task is to track an object as it moves from frame to frame within a video sequence. There are a myriad of applications for such capability and the underlying technologies to achieve this tracking are very well understood. More recently, deep convolutional neural networks have been employed to not only track, but also to classify objects as they are tracked from frame to frame. These models can be used in a tracking paradigm known as tracking by detection and can achieve very high tracking accuracy. The major drawback to these deep neural networks is the large amount of mathematical operations that must be performed for each inference which negatively impacts the number of tracked frames per second. For edge applications residing on size, weight, and power limited platforms, such as unmanned aerial vehicles, high frame rate and low latency real time tracking can be an elusive target. To overcome the limited power and computational resources of an edge compute device, various optimizations have been performed to trade off tracking speed, accuracy, power, and latency. Previous works on motion based interpolation with neural networks either do not take into account the latency accrued from camera image capture to tracking result or they compensate for this latency but are bottlenecked by the motion interpolation operation instead. The algorithm presented in this work gains the performance speedup used in previous motion based neural network inference papers and also performs a novel look back operation that is less cumbersome than other competing motion interpolation methods.

Smoke detectors generally present the most frequently used fire detectors. These detectors have great appliance because smoke presents the consequence of many fires. These detectors can be realized as point smoke detectors and linear smoke detectors, while special smoke detectors are used for special purposes. Their efficiency is the biggest in the cases where fuel material produces smaller or larger amounts of smoke. The use of smoke detectors in the form of linear smoke detectors is particularly significant in rooms with huge dimensions and huge ceiling height. This paper was written to present work principle of linear smoke detectors and their installation in objects related to valid standards (EN 54, BS, NPB 88-2001, VDE 088-2 and NFPA 72).