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1
Blondel, Paul, Alex Potelle, Claude Pégard e Rogelio Lozano. "Collaborative training of far infrared and visible models for human detection". International Journal for Simulation and Multidisciplinary Design Optimization 10 (2019): A15. http://dx.doi.org/10.1051/smdo/2019016.
Testo completoAbstract (sommario):
This paper is about the collaborative training of a far infrared and a visible spectrum human detector; the idea is to use the strengths of one detector to fill the weaknesses of the other detector and vice versa. At first infrared and visible human detectors are pre-trained using initial training datasets. Then, the detectors are used to collect as many detections as possible. The validity of each detection is tested using a low-level criteria based on an objectness measure. New training data are generated in a coupled way based on these detections and thus reinforce both the infrared and the visible human detectors in the same time. In this paper, we showed that this semi-supervised approach can significantly improve the performance of the detectors. This approach is a good solution to generate infrared training data, this kind of data being rarely available in the community.
2
AL-Rawi, Muhanned, e Muaayed AL-Rawi. "Combined Detector with Retraining Data Sequence". Technological Engineering 15, n. 1 (1 ottobre 2018): 47–50. http://dx.doi.org/10.1515/teen-2018-0009.
Testo completoAbstract (sommario):
Abstract Two detectors are presented in this paper which are used to handle intersymbol interference introduced by the communication channels. These two detectors are based on combination of nonlinear equalizer and Viterbi detector. The first detector, which was previously developed, is named Combined Detector1(CDR1), while, the second detector, which is the contribution of this paper, is named Combined Detector-2(CDR2). CDR2 is similar to CDR1 but with retraining data sequence. These detectors are tested beside nonlinear equalizer using data transmission at 9.6kb/s over telephone channel. Simulation results show that the performance of CDR2 is better than the performance of CDR1 while the performance of CDR1 is better than the performance of nonlinear equalizer.
3
Martyniuk, P., e A. Rogalski. "Theoretical modelling of MWIR thermoelectrically cooled nBn HgCdTe detector". Bulletin of the Polish Academy of Sciences: Technical Sciences 61, n. 1 (1 marzo 2013): 211–20. http://dx.doi.org/10.2478/bpasts-2013-0020.
Testo completoAbstract (sommario):
Abstract The paper reports on the medium wavelength infrared (MWIR) unipolar barrier infrared detector (UBIRD) nBn/B-n type (n-type barrier) HgCdTe detector’s photoelectrical performance. The UBIRD nBn/B-n type HgCdTe detector was modelled using commercially available software APSYS. Detailed analysis of the detector’s performance (such as dark current, photocurrent, responsivity, and detectivity) versus bias voltage, operating temperatures, and structural parameters (cap, barrier, and absorber’s doping as well as cap and barrier compositions) were performed pointing out optimal working conditions. Both conduction and valence band alignments of the HgCdTe nBn/B-n type detector structure was simulated stressing their importance on detectors performance. It was shown that higher operation temperature (HOT) conditions achieved by commonly used thermoelectric (TE) coolers allow to obtain detectivities of D* = (3-10)×109 cmHz1/2/W at T = 200 K for detectors with cut-off wavelength of 5.2 μm The differential resistance area product of RA = 0.15-0.4 cm2 at T = 230 K for bias voltage V = 50 mV was estimated. Finally, the state of the art of UBIRD HgCdTe nBn/B-n type detector performance was compared to InAs/GaSb/B-Al0.2Ga0.8Sb T2SLs nBn detector, InAs/GaSb T2SLs PIN and the HOT HgCdTe bulk photodiodes’ operated at near-room temperature (T = 230 K). It was shown that the RA product of the MWIR UBIRD nBn/B-n type HgCdTe detector can reach a comparable level to the state of the art of the HgCdTe HOT bulk photodiodes and two types of type-II superlattice detectors: PIN photodiodes and nBn detectors
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Chen, Jiangtian. "Analysis of the Principle and Applications of Infrared Detectors in Cosmology". Highlights in Science, Engineering and Technology 72 (15 dicembre 2023): 793–99. http://dx.doi.org/10.54097/7g1bc173.
Testo completoAbstract (sommario):
As a matter of fact, infrared detectors are widely used and applied in cosmology detections. On this basis, this paper provides a comprehensive analysis of the principles and applications of infrared detectors in the field of cosmology. The paper discusses the two main types of infrared detectors: bolometer arrays and photon detector arrays, explaining their underlying principles and highlighting their applications in astronomy. It also presents the advancements in infrared detector technology, such as the use of different materials and the development of large-scale bolometer arrays. The paper further discusses the significant achievements made by various institutions in the field of infrared astronomy, including the discoveries based on detection result from SOFIA and WISE. Overall, this paper offers a comprehensive overview of the principles and applications of infrared detectors in cosmology, providing valuable information for enthusiasts in the field. These results shed light on guiding further exploration of space detectors.
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Koike, Ryuto, Masahiro Kaneko e Naoaki Okazaki. "OUTFOX: LLM-Generated Essay Detection Through In-Context Learning with Adversarially Generated Examples". Proceedings of the AAAI Conference on Artificial Intelligence 38, n. 19 (24 marzo 2024): 21258–66. http://dx.doi.org/10.1609/aaai.v38i19.30120.
Testo completoAbstract (sommario):
Large Language Models (LLMs) have achieved human-level fluency in text generation, making it difficult to distinguish between human-written and LLM-generated texts. This poses a growing risk of misuse of LLMs and demands the development of detectors to identify LLM-generated texts. However, existing detectors lack robustness against attacks: they degrade detection accuracy by simply paraphrasing LLM-generated texts. Furthermore, a malicious user might attempt to deliberately evade the detectors based on detection results, but this has not been assumed in previous studies. In this paper, we propose OUTFOX, a framework that improves the robustness of LLM-generated-text detectors by allowing both the detector and the attacker to consider each other's output. In this framework, the attacker uses the detector's prediction labels as examples for in-context learning and adversarially generates essays that are harder to detect, while the detector uses the adversarially generated essays as examples for in-context learning to learn to detect essays from a strong attacker. Experiments in the domain of student essays show that the proposed detector improves the detection performance on the attacker-generated texts by up to +41.3 points F1-score. Furthermore, the proposed detector shows a state-of-the-art detection performance: up to 96.9 points F1-score, beating existing detectors on non-attacked texts. Finally, the proposed attacker drastically degrades the performance of detectors by up to -57.0 points F1-score, massively outperforming the baseline paraphrasing method for evading detection.
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Wang, Mingyang, Zheng Li, Bo Xiong e Yongguang Xiao. "Electrical Characteristics of 3D Trench Electrode Germanium Detector with Nested Complementary Cathodes". Micromachines 14, n. 11 (1 novembre 2023): 2051. http://dx.doi.org/10.3390/mi14112051.
Testo completoAbstract (sommario):
High-purity germanium detectors, widely employed in fields such as aerospace applications based on radiation detection principles, have garnered attention due to their broad detection range and fast response time. However, these detectors often require larger sensitive area volumes to achieve larger signals and higher detection efficiency. Additionally, the large distance between the electrodes contributes to an issue of incomplete charge collection, which significantly restricts their application in space applications. To enhance the electrical performance of high-purity germanium detectors, this study introduces a strategy: designing the detector’s cathode electrode into a 3D trench shape with nested complementary cathodes. This design greatly reduces the electrode spacing, endowing the detector with superior electrical characteristics, such as a smaller dead zone and improved charge collection efficiency. Performance simulations of the novel detector structure were conducted using the semiconductor device simulation software Sentaurus TCAD (2019.03). The simulation results confirmed that the nested complementary 3D trench electrode high-purity germanium detector exhibits excellent electrical features, including a larger sensitive area volume, rapid charge collection, and good cell isolations. This approach has the potential to effectively expand the application scenarios of high-purity germanium detectors. Depending on different operational environments and requirements, nested complementary 3D trench electrode high-purity germanium detectors of appropriate structural dimensions can be chosen. The experimental findings of this study hold a significant reference value for enhancing the overall structure of high purity germanium detectors and facilitating their practical application in the future.
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Turunen, Vesa, Marko Kosunen, Sami Kallioinen, Aarno Pärssinen e Jussi Ryynänen. "The effects of non-linearity in spectrum sensing receivers". International Journal of Microwave and Wireless Technologies 8, n. 7 (15 luglio 2015): 995–1003. http://dx.doi.org/10.1017/s1759078715001130.
Testo completoAbstract (sommario):
This paper analyses the effects of receiver non-linearity on the performance of the most commonly utilized signal detectors in cognitive radio systems. The analysis covers both self-modulation products of a single orthogonal frequency-division multiplexing (OFDM) signal and intermodulation(IM)products of two OFDM signals, and also their contribution to the probability of false detections. As a result, this work presents the linearity requirements for the spectrum sensor receiver front-end as a function of the sensitivity of the signal detector. Furthermore, we show that the cyclostationary feature detectors are more robust than the energy detectors against IM products of multiple interferers. Theoretical results are verified in measurements with a cyclostationary feature detector using digital video broadcasting – terrestrial (DVB-T) signals as an example.
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Chi, Yao Dan, Di Yuan e Xiao Tian Yang. "Introduction to Intelligent Transportation Vehicle Detector". Applied Mechanics and Materials 496-500 (gennaio 2014): 1369–72. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.1369.
Testo completoAbstract (sommario):
Increasingly grim situation in recent years due to traffic, the new traffic conditions to the vehicle detector development and application of proposed new requirements, this paper introduces a new form of intelligent transportation vehicle detectors at the request of Vehicle Detector Research be brief, a brief analysis of a variety of vehicle detector works that feature discusses the trend of vehicle detector’s development
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Ambrožová, Iva, Kateřina Pachnerová Brabcová, Vyacheslav A. Shurshakov, Raisa V. Tolochek e Satoshi Kodaira. "ANGULAR DEPENDENCE OF TRACK-ETCH DETECTOR HARZLAS TD-1". Radiation Protection Dosimetry 186, n. 2-3 (7 novembre 2019): 219–23. http://dx.doi.org/10.1093/rpd/ncz206.
Testo completoAbstract (sommario):
Abstract Track-etched detectors are commonly used also for radiation monitoring onboard International Space Station. To be registered in track-etched detectors, the particle needs to meet several criteria—it must have linear energy transfer above the detection threshold and strike the detector’s surface under an angle higher than the so-called critical angle. Linear energy transfer is then estimated from calibration curve from the etch rate ratio V that is calculated from parameters of individual tracks appearing on the detector’s surface after chemical etching. It has been observed that V can depend on the incident angle and this dependence can vary for different detector materials, etching and evaluating conditions. To investigate angular dependence, detectors (Harzlas TD-1) were irradiated at HIMAC by several ions under angles from 0° to 90°. The correction accounting not only for critical angle but also for dependence of V on the incident angle is introduced and applied to spectra measured onboard International Space Station.
10
Kushoro, Matteo Hakeem, Marica Rebai, Marco Tardocchi, Carmen Altana, Carlo Cazzaniga, Eliana De Marchi, Francesco La Via et al. "Detector Response to D-D Neutrons and Stability Measurements with 4H Silicon Carbide Detectors". Materials 14, n. 3 (26 gennaio 2021): 568. http://dx.doi.org/10.3390/ma14030568.
Testo completoAbstract (sommario):
The use of wide-band-gap solid-state neutron detectors is expanding in environments where a compact size and high radiation hardness are needed, such as spallation neutron sources and next-generation fusion machines. Silicon carbide is a very promising material for use as a neutron detector in these fields because of its high resistance to radiation, fast response time, stability and good energy resolution. In this paper, measurements were performed with neutrons from the ISIS spallation source with two different silicon carbide detectors together with stability measurements performed in a laboratory under alpha-particle irradiation for one week. Some consideration to the impact of the casing of the detector on the detector’s counting rate is given. In addition, the detector response to Deuterium-Deuterium (D-D) fusion neutrons is described by comparing neutron measurements at the Frascati Neutron Generator with a GEANT4 simulation. The good stability measurements and the assessment of the detector response function indicate that such a detector can be used as both a neutron counter and spectrometer for 2–4 MeV neutrons. Furthermore, the absence of polarization effects during neutron and alpha irradiation makes silicon carbide an interesting alternative to diamond detectors for fast neutron detection.
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Kania, D. R. "Radiation-induced conductivity: High-speed detection of X rays and neutrons". Laser and Particle Beams 9, n. 1 (marzo 1991): 91–97. http://dx.doi.org/10.1017/s0263034600002354.
Testo completoAbstract (sommario):
Radiation-induced conductivity (RIC) is a generalized term for photoconductivity expanded to include nonelectromagnetic radiation. RIC offers several distinct advantages for the detection of high-energy radiation: (i) the speed of response of a detector is determined by a bulk property of the material, the carrier lifetime; (ii) the detector can be directly illuminated by the signal radiation-no dead layer; and (iii) the selection of the detector material and its geometry is very flexible. This paper will discuss the principles of RIC for X rays and neutrons, the fabrication of detectors, and applications. RIC detectors have been fabricated from Si, InP, GaAs, and diamond. Bulk and thin film materials have been used. The carrier lifetime was varied by the introduction of trapping sites in the material. This can be done in the material production process in the case of doping (e.g., Fe in InP) and thin films or produced from radiation damage of a pure crystalline material. Lifetimes as short as a few picoseconds have been observed. A variety of detectors have been tested using pulsed optical, X ray, and neutron sources. Absolute sensitivities and temporal response has been measured and compared to theoretical models of the detector's performance for both X rays and neutrons. Finally, applications of these detectors to inertial confinement fusion measurement will be shown.
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Begeman, Christopher, Dennis Helder, Larry Leigh e Chase Pinkert. "Relative Radiometric Correction of Pushbroom Satellites Using the Yaw Maneuver". Remote Sensing 14, n. 12 (12 giugno 2022): 2820. http://dx.doi.org/10.3390/rs14122820.
Testo completoAbstract (sommario):
Earth-imaging satellites commonly acquire multispectral imagery using linear array detectors formatted as a pushbroom scanner. Landsat 8, a well-known example, uses pushbroom scanning and thus has 73,000 individual detectors. These 73,000 detectors are split among 14 different focal plane modules (FPM), and each detector and FPM exhibit unique behavior when monitoring a uniform radiance value. To correct for each detector’s differences in sensor measurement, a novel technique of relative gain estimation that employs an optimized modified signal-to-noise ratio through a 90∘ yaw maneuver, also known as side slither, is presented that allows for both FPM and detector-level relative gain calculation. A periodic model based on in-scene FPM corrections was designed as a go-to model for all bands aboard Landsat 8. Relative gains derived from the side-slither technique and applied to imagery provide a visual and statistical reduction in detector-level and FPM-level striping and banding in Landsat 8 imagery. Both reflective and thermal wavelengths are corrected to a level that rivals current operational methods. While Landsat 8 is used as an example, the methodology is applicable to all linear array sensors that can perform a 90∘ yaw maneuver.
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Huang, Yujie, Jing Yang, Degang Zhao, Yuheng Zhang, Zongshun Liu, Feng Liang e Ping Chen. "Role of Vacancy Defects in Reducing the Responsivity of AlGaN Schottky Barrier Ultraviolet Detectors". Nanomaterials 12, n. 18 (11 settembre 2022): 3148. http://dx.doi.org/10.3390/nano12183148.
Testo completoAbstract (sommario):
The spectral response properties of AlGaN Schottky barrier detectors with different Al content were investigated. It was found that the responsivity of AlGaN detectors decreases with increase in Al content in AlGaN. It was found that neither dislocation density nor the concentration of carbon and oxygen impurities made any remarkable difference in these AlGaN devices. However, the positron annihilation experiments showed that the concentration of Al or Ga vacancy defects (more likely Ga vacancy defects) in AlGaN active layers increased with the increase in Al content. It is assumed that the Al or Ga vacancy defects play a negative role in a detector’s performance, which increases the recombination of photogenerated carriers and reduces the detector responsivity. It is necessary to control the concentration of vacancy defects for the high performance AlGaN detectors.
14
Vasilyeva, O., e Y. Kozak. "ANALYSIS OF THE DETERMINING METHODS OF THE THERMAL FIRE DETECTORS TIME PARAMETERS". Municipal economy of cities 1, n. 175 (3 aprile 2023): 136–44. http://dx.doi.org/10.33042/2522-1809-2023-1-175-136-144.
Testo completoAbstract (sommario):
The article is devoted to substantiating the pulse method of time parameters determining - the thermal fire detectors' operation time and constant time with a thermal resist sensitive element. Significant research is that the time parameters of thermal fire detectors include the operation time and constant time that are interconnected. It is shown that the contribution of constant time to the operation time can be up to 20% at a speed of change in ambient temperature 0.50C per C-1. It is also found that their testing is used to determine the time parameters of thermal fire detectors, which are divided into stationary or autonomous and operational or object. The article specifies that the disadvantage of inpatient tests with the help of heat chambers is the asymmetry of the airflow distribution and temperature, and the lack of such tests employing standard combustion cells is that the thermal impact parameters on the fire detector sensitive element are not normalized. The research results have found that the amount of the fire detectors' constant time is not determined, and only control of the fire detectors' operation time is carried out according to the admission criteria. During the object tests, in most cases, the thermal impact on a fire detector's sensitive element with the help of small heat chambers is realized, the purpose of such tests is to check the fire detectors' performance without obtaining estimates of their operation time and constant time. It is worth noting that the thermal impact on the fire detector's sensitive element can be carried out with the help of both external and internal sources of heat. The second option is characteristic of fire detectors with a thermal resist sensitive element and is based on the use of the Joule-Lenz effect (heating of a conductor or semiconductor is directly proportional to its resistance, the duration of the current and the square of the current). In this case, new opportunities are opened to improve the efficiency of the fire detectors operation of this type. Keywords: fire equipment, detectors, improving the efficiency of the fire detectors operation, time parameters of thermal fire detectors.
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Bieszczad, Grzegorz, e Mariusz Kastek. "Measurement of Thermal Behavior of Detector Array Surface with the Use of Microscopic Thermal Camera". Metrology and Measurement Systems 18, n. 4 (1 gennaio 2011): 679–90. http://dx.doi.org/10.2478/v10178-011-0064-6.
Testo completoAbstract (sommario):
Measurement of Thermal Behavior of Detector Array Surface with the Use of Microscopic Thermal Camera Modern infrared cameras are constructed with two main types of infrared detectors: photon detectors and thermal detectors. Because of economic reasons, vast numbers of modern thermal cameras are constructed with the use of infrared microbolometric detectors which belong to the group of thermal detectors. Thermal detectors detect incident infrared radiation by measuring changes of temperature on the surface of a special micro-bridge structure. Thermal detectors, like microbolometric detectors on one hand should be sensitive to changing temperature to accurately measure incoming infrared radiation from the observed scene, on the other hand there are many other phenomena that change the temperature of the detector and influence the overall response of the detector. In order to construct an accurate infrared camera, there is a need to evaluate these phenomena and quantify their influence. In the article the phenomenon of self heating due to the operation of the readout circuit is analyzed on an UL 03 19 1 detector. The theoretical analysis is compared with the results of conducted measurements. Measurements with a type SC7900VL thermographic camera were performed to measure the thermodynamic behavior of the UL 03 19 1 detector array.
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Stanton, M., W. C. Phillips, Y. Li e K. Kalata. "The detective quantum efficiency of CCD and vidicon-based detectors for X-ray crystallographic applications". Journal of Applied Crystallography 25, n. 5 (1 ottobre 1992): 638–45. http://dx.doi.org/10.1107/s0021889892005211.
Testo completoAbstract (sommario):
The detective quantum efficiency (DQE) characterizes the measurement uncertainty introduced by a detector. A formulation of the DQE for CCD and vidicon-based X-ray integrating detectors is developed and illustrated with five model detectors. A comparison of the calculated and measured DQEs for two of these detectors is presented. From an examination of the DQEs for the model detectors, generalizations are made regarding detector designs.
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Zhang, C., G. Wu, Z. Li, H. Li, Z. Lu, H. Zhang, X. Wang et al. "The response of an Al-10B4C coupled neutron detector based on PIPS technology to Cf-252". Journal of Instrumentation 18, n. 11 (1 novembre 2023): P11005. http://dx.doi.org/10.1088/1748-0221/18/11/p11005.
Testo completoAbstract (sommario):
Abstract After decades of discussions, it has been firmly established that detectors made of silicon-based semiconductor materials can be effectively used for neutron detection by simply coating them with suitable substances. The incident thermal neutrons interact with the coating neutron-sensitive materials such as 10B and 6LiF, resulting in the production of secondary charged particles which can be effectively detected in the sequencial silicon substrate. In this article, the detector system was designed with a coupled neutron detector structure which combined a silicon detector with a 10B4C film in various forms. The 10B4C layer was deposited on the substract with electron beam evaporation method. Two kinds of structrue were discussed: (1) one was the direct contact neutron detector by depositing 10B4C directly onto the front surface of silicon-based detectors; (2) the other was the coupled neutron detectors by depositing 10B4C onto substrates made from different materials such as Al and glass which then coupled with silicon-based detectors. The responses of these neutron detectors to neutrons (Cf-252) were measured individually. It's showen that the detection capability of direct contact neutron detectors was lower than the coupled neutron detectors. For the coupled detectors, the detector by depositing 10B4C on the aluminum substrate was found to be superior than that by depositing 10B4C on the glass substrate.
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Muchmore, Steven W. "Experiences with CCD detectors on a home X-ray source". Acta Crystallographica Section D Biological Crystallography 55, n. 10 (1 ottobre 1999): 1669–71. http://dx.doi.org/10.1107/s0907444999010689.
Testo completoAbstract (sommario):
Charged-coupled device (CCD) detectors have been widely accepted as detectors for collecting X-ray diffraction images. The CCD detector offers a sensitive detection system well suited for diffraction analysis and, compared with other detectors on the market, a relatively rapid system for read-out of the collected image. The two predominant markets for the CCD detector have been those in which relatively short exposure times are used,i.e.small-molecule X-ray diffraction and large-molecule crystallography at high-intensity synchrotron sources. CCD detectors have not been commonly used on rotating-anode X-ray sources for large-molecule crystallography. Comparison of the performance of the CCD detectors with commercially available image-plate detectors shows that the CCD detectors function in a similar fashion to image-plate-based detectors.
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Madejczyk, P., W. Gawron, A. Kębłowski, K. Mlynarczyk, D. Stępień, P. Martyniuk, A. Rogalski, J. Rutkowski e J. Piotrowski. "Higher Operating Temperature IR Detectors of the MOCVD Grown HgCdTe Heterostructures". Journal of Electronic Materials 49, n. 11 (24 agosto 2020): 6908–17. http://dx.doi.org/10.1007/s11664-020-08369-3.
Testo completoAbstract (sommario):
Abstract This paper summarizes progress in metal organic chemical vapour deposition (MOCVD) technology achieved in recent years at the Institute of Applied Physics, Military University of Technology and VIGO System S.A. MOCVD with a wide range of composition and donor/acceptor doping and without post-growth annealing is a very convenient tool for the deposition of HgCdTe epilayers used for uncooled infrared detectors. Particular attention is focused on: surface morphology improvement, doping issues, diffusion processes during growth study, substrate issues, crystallographic orientation selection. In this respect, MOCVD technology improvement influencing IR detector parameters is shown. CdTe buffer layer deposition allows HgCdTe heterostructure growth on GaAs substrates. Theoretical modelling using APSYS platform supports designing and better understanding of the carrier transport mechanism in detector’s structures. Secondary ion mass spectrometry profiles allows to compare projected and obtained structures and revealed diffusion processes of the elements. A wide range of different types of infrared detectors operating at high operating temperature conditions has been constructed: photoresistors, non-equilibrium photodiodes, dual-band photodiodes, barrier and multiple detectors. The methodical research efforts contributed to the time constant reduction are important in many detector applications. Future challenges and prospects are also discussed.
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Jaume, Rafel, Rodrigo Tenorio e Alicia M. Sintes. "Assessing the Similarity of Continuous Gravitational-Wave Signals to Narrow Instrumental Artifacts". Universe 10, n. 3 (4 marzo 2024): 121. http://dx.doi.org/10.3390/universe10030121.
Testo completoAbstract (sommario):
Continuous gravitational-wave (CW) signals are long-lasting quasi-monochromatic gravitational-wave signals expected to be emitted by rapidly rotating non-axisymmetric neutron stars. Depending on the rotational frequency and sky location of the source, certain CW signals may behave in a similar manner to narrow-band artifacts present in ground-based interferometric detectors. Part of the detector characterization tasks in the current generation of interferometric detectors (Advanced LIGO, Advanced Virgo, and KAGRA) aim at understanding the origin of these narrow artifacts, commonly known as "spectral lines". It is expected that similar tasks will continue after the arrival of next-generation detectors (e.g., Einstein Telescope and Cosmic Explorer). Typically, a fraction of the observed lines in a given detector can be associated to one or more instrumental causes; others, however, have an unknown origin. In this work, we assess the similarity of CW signals to spectral lines in order to understand whether a CW signal may be mistaken for a noise artifact. Albeit astrophysically unlikely, our results do not rule out the possibility of a CW signal being visible in the detector’s power spectrum.
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Kalina Szafarczyk. "Reducing the Multi-Sensor Smoke Detectors Susceptibility to False Triggering". SAFETY & FIRE TECHNOLOGY 60, n. 2 (30 dicembre 2022): 164–74. http://dx.doi.org/10.12845/sft.60.2.2022.9;.
Testo completoAbstract (sommario):
Cel: An assessment of the possibility of reducing the susceptibility of fire detectors to false alarms was carried out by: 1) analysing the impact of changing the operating modes of a multi-sensor detector on minimizing false alarms, and 2) verifying, using ANOVA tests, two hypotheses: either the settings or the sensitivity of the sensor affect the susceptibility of the detectors to false alarms. Projekt i metody: In order to assess the impact of false alarms on the operation of facilities equipped with a Fire Alarm System, a survey was conducted, directed at their administrators. A study of the fire detectors susceptibility to false alarms included placing the DTC-6046 multi-sensor detector in a closed test chamber and initiating the detector’s triggering by a deceptive agent. It was then observed whether the detector would initiate a fire alarm depending on different operating mode settings. The operation of the sensors was changed to interdependent, independent or coincidence work. Sensitivity settings of the sensors were changed from normal to increased by 20%, decreased by 20% or by 40%. An analysis using ANOVA test was conducted to verify which settings have a significant impact on minimising false alarms. Based on the results, example configuration guidelines were developed. Wyniki: Based on the study, the following main results were formulated. The configuration least prone to false triggering is the one in which the sensors operate interdependently and the sensitivity is reduced by 40%. The highest number of false alarms was observed when sensitivity was increased by 20% with independent sensors and in coincidence, as well as for independent sensors working at normal sensitivity. Performing verification using ANOVA analysis of variance, the hypothesis that sensor settings have a statistically significant effect on minimising false alarms was rejected. Wnioski: There is a need to search for and implement ways to minimise false alarms of Fire Alarm Systems. The most common reason for false triggering of fire detectors are external factors that are not fire hazards (e.g. dust, dirt). The way of minimising false alarms is a proper setting of the detector operating modes (not often used in practice). The operating modes are based on changing the settings of sensor cooperation and detector sensitivity, where changing only the settings of the sensors does not result in such significant changes as changing the sensitivity of the detectors to increased or decreased compared to normal (result of ANOVA analysis). Słowa kluczowe: fire detector, false alarms, detector operating modes, reduction of false triggering of fire detectors
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Yermolayev, D. M., E. A. Polushkin, S. Yu Shapoval, V. V. Popov, K. V. Marem’yanin, V. I. Gavrilenko, N. A. Maleev et al. "Detection of Terahertz Radiation by Dense Arrays of InGaAs Transistors". International Journal of High Speed Electronics and Systems 24, n. 01n02 (marzo 2015): 1550002. http://dx.doi.org/10.1142/s0129156415500020.
Testo completoAbstract (sommario):
Detection of terahertz radiation by GaAs transistor structures has been studied experimentally. The two types of samples under study included dense arrays of HEMTs and large-apertures detectors. Arrays consisted of parallel and series chains with asymmetric gate transistors for enhanced photoresponse on terahertz radiation. We investigated two types of wide-aperture detectors: grating gate detector, and single gate detector with bow-tie antenna. Wide-aperture detectors were symmetrical. Studies of transistor chains have shown that two essential features for this type of detector are the presence of asymmetry in the gate, and the type of connection between individual transistors themselves. Wide-aperture detectors have also been tested by narrow beams of terahertz radiation, which allows analyzing the role influence of individual parts of the detector for total sensitivity to terahertz excitation. The sensitivity and noise equivalent power of the detectors were evaluated.
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Martínek, Petr, Jana Míšková e Pavel Podaný. "Corrosion Resistance of Casings for Metal Detectors in Food Industry Made of Cr-Ni Stainless Steel". Key Engineering Materials 647 (maggio 2015): 248–54. http://dx.doi.org/10.4028/www.scientific.net/kem.647.248.
Testo completoAbstract (sommario):
The paper discusses the problem of recurrent corrosion of casing of metal detectors used in food industry. The detector casing is fabricated by welding sheets of X5CrNi18-10 stainless steel. The detectors in service suffered non-uniform spot corrosion. The likely cause of the corrosion attack was the accumulated contamination of the detector surface with cleaning and disinfecting agents containing chlorine. The sheet surfaces of the original detectors were shot-blasted. After the sheet finishing process was changed to grinding and minor design changes were made, the corrosion resistance of the detector casing improved. The enhanced corrosion resistance of the detectors with ground surfaces was confirmed by salt spray tests. The use of the modified detectors then led to a lower number of complaints about the devices.
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Taguchi, Takeyoshi, Christian Brönnimann e Eric F. Eikenberry. "Next generation X-ray detectors for in-house XRD". Powder Diffraction 23, n. 2 (giugno 2008): 101–5. http://dx.doi.org/10.1154/1.2912455.
Testo completoAbstract (sommario):
A novel type X-ray detector, called PILATUS, has been developed at the Paul Scherrer Institut in Switzerland during the last decade. PILATUS detectors are two-dimensional hybrid pixel array detectors, which operate in single-photon counting mode. PILATUS detectors feature a very wide dynamic range (1:1 000 000), very short readout time (<3.0 ms), no readout noise, and very high counting rate (>2×106counts/s/pixel). In addition, a lower energy threshold can be set in order to suppress fluorescence background from the sample, thus a very good signal-to-noise ratio is achieved. The combination of these features for area detectors is unique and thus the PILATUS detectors are considered to be the next generation X-ray detectors. The basic building block of all the detectors is the PILATUS module having an active area of 83.8×33.5 mm2. The PILATUS 100K is a complete detector system with one module. PILATUS detector systems can have other configurations, including large area systems consisting of 20 to 60 modules that can cover up to an area of 431×448 mm2. Such large systems are mainly used for macromolecular structure determination, such as protein crystallography and small angle X-ray scattering. The PILATUS 100K detector can be easily adapted to many systems; the single-module detector is integrated to an in-house X-ray diffraction (XRD) system. Examples of XRD measurements with the PILATUS 100K detector are given.
25
Baum, Sebastian, Zachary Bogorad e Peter W. Graham. "Gravitational wave measurement in the mid-band with atom interferometers". Journal of Cosmology and Astroparticle Physics 2024, n. 05 (1 maggio 2024): 027. http://dx.doi.org/10.1088/1475-7516/2024/05/027.
Testo completoAbstract (sommario):
Abstract Gravitational Waves (GWs) have been detected in the ∼ 100 Hz and nHz bands, but most of the gravitational spectrum remains unobserved. A variety of detector concepts have been proposed to expand the range of observable frequencies. In this work, we study the capability of GW detectors in the “mid-band”, the ∼ 30 mHz– 10 Hz range between LISA and LIGO, to measure the signals from and constrain the properties of ∼ 1 – 100 M ⊙ compact binaries. We focus on atom-interferometer-based detectors. We describe a Fisher matrix code, AIMforGW, which we created to evaluate their capabilities, and present numerical results for two benchmarks: terrestrial km-scale detectors, and satellite-borne detectors in medium Earth orbit. Mid-band GW detectors are particularly well-suited to pinpointing the location of GW sources on the sky. We demonstrate that a satellite-borne detector could achieve sub-degree sky localization for any detectable source with chirp mass ℳ c ≲ 50 M ⊙. We also compare different detector configurations, including different locations of terrestrial detectors and various choices of the orbit of a satellite-borne detector. As we show, a network of only two terrestrial single-baseline detectors or one single-baseline satellite-borne detector would each provide close-to-uniform sky-coverage, with signal-to-noise ratios varying by less than a factor of two across the entire sky. We hope that this work contributes to the efforts of the GW community to assess the merits of different detector proposals.
26
Esfandi, Fatemeh, Shahyar Saramad e Mohammad Amin Jalilvand. "Finite Element Simulation of a Novel Nano 3D Semiconductor Detector Fabricated by Anodizing the Aluminium". Advanced Materials Research 829 (novembre 2013): 212–16. http://dx.doi.org/10.4028/www.scientific.net/amr.829.212.
Testo completoAbstract (sommario):
The unique geometry of micro 3D semiconductor detectors, presents several advantages over conventional planar silicon detectors. But, manufacturing these kind of detectors requires high technology. The novel idea to achieve a high performance and low cost semiconductor detector is using the nanopattern of anodized aluminium as a mask to create nano3D detectors. The simulation results show that this novel nano3D radiation hard semiconductor detector with collection time less than 10 ps and full depletion voltage less than one volt can become increasingly important for possible future upgrades of 3D detectors of the Large Hadron Collider (LHC) at CERN and also medical imaging applications.
27
Færch, Laust, Wolfgang Dierking, Nick Hughes e Anthony P. Doulgeris. "A comparison of constant false alarm rate object detection algorithms for iceberg identification in L- and C-band SAR imagery of the Labrador Sea". Cryosphere 17, n. 12 (15 dicembre 2023): 5335–55. http://dx.doi.org/10.5194/tc-17-5335-2023.
Testo completoAbstract (sommario):
Abstract. In this study, we pursue two objectives: first, we compare six different “constant false alarm rate” (CFAR) algorithms for iceberg detection in SAR images, and second, we investigate the effect of radar frequency by comparing the detection performance at C- and L-band. The SAR images were acquired over the Labrador Sea under melting conditions. In an overlapping optical Sentinel-2 image, 492 icebergs were identified in the area. They were used for an assessment of the algorithms' capabilities to accurately detect them in the SAR images and for the determination of the number of false alarms and missed detections. By testing the detectors at varying probability of false alarm (PFA) levels, the optimum PFA for each detector was found. Additionally, we considered the effect of iceberg sizes in relation to image resolution. The results showed that the overall highest accuracy was achieved by applying a log-normal CFAR detector to the L-band image (F score of 70.4 %), however, only for a narrow range of PFA values. Three of the tested detectors provided high F scores above 60 % over a wider range of PFA values both at L- and C-band. Low F scores were mainly caused by missed detections of small-sized (<60 m) and medium-sized (60–120 m) icebergs, with approximately 20 %–40 % of the medium icebergs and 85 %–90 % of small icebergs being missed by all detectors. The iDPolRAD detector, which is sensitive to volume scattering, is less suitable under melting conditions.
28
Ding, Yuening, Heyang Weng, Jili You e Yuanbo Zhang. "Comparison of Different Planet Detectors: Juno Spacecraft, Akatsuki and Perseverance Mars Rover". Highlights in Science, Engineering and Technology 38 (16 marzo 2023): 862–66. http://dx.doi.org/10.54097/hset.v38i.5971.
Testo completoAbstract (sommario):
In the modern society, scholars and researchers have already gained a fundamental understanding of our solar system, based on the multiple samples taken from a variety of detectors. Indeed, the detectors of planets in solar system play a vital role to investigate different planets. Therefore, with this in mind, this paper has compared with several state-of-art main-stream detectors, including Juno spacecraft, Akatsuki and Perseverance Mars Rover. According to the sample from Perseverance Mars Rover, scientists can make a progress in the understanding of Mars’s composition and whether there is the scent of ancient life on Mars. In the accordance with Akatsuki’s data, people have concluded the atmospheric structure on Venus. Based on the graphs gained by the Juno spacecraft, modern scientists can correct the theory of Jovian Lighting and understand the source of Zodiacal light. As a result, the thesis has concluded these three types of detectors ‘s characters, providing a relatively objective references about today’s detector’s features for the future development. Overall, these results shed light on guiding further exploration of planet detections.
29
Mindur, Bartosz, Tomasz Fiutowski, Stefan Koperny, Piotr Wiącek e Władysław Dąbrowski. "Investigation of Copper-Less Gas Electron Multiplier Detectors Responses to Soft X-rays". Sensors 20, n. 10 (14 maggio 2020): 2784. http://dx.doi.org/10.3390/s20102784.
Testo completoAbstract (sommario):
In this paper, we report on the systematic study of different variants of X-ray detectors based on Gas Electron Multiplier (GEM) technology using modified GEM foils with greatly reduced amount of copper. The main goal of this study was understanding the performance of such detectors applied in X-Ray Fluorescence (XRF) elemental analysis. Reduction of the amount of copper in the detector structure is crucial for suppression of XRF background from copper, but one has to ensure that key detector parameters are not affected by such modification. The tested detector variants include detectors with different types of copper-less GEM foils, which have been manufactured starting from standard copper-clad foils and removing partially the copper layer in additional post-processing steps. The results are analyzed and discussed with a particular focus on the energy resolution, uniformity of gas gain and energy resolution across the detector area, and on the long-term stability of the gas gain. Long-term stability tests performed for selected detectors do not indicate for any accelerated aging of the copper-less detectors compared to standard detectors using copper-clad GEM foils. The presented results lead us to conclude that the copper-less GEM detectors are promising devices to suppress the XRF background.
30
Kushnir, Andrii, Bohdan Kopchak e Andrii Gavryliuk. "Operational algorithm for a heat detector used in motor vehicles". Eastern-European Journal of Enterprise Technologies 3, n. 10(111) (30 giugno 2021): 6–18. http://dx.doi.org/10.15587/1729-4061.2021.231894.
Testo completoAbstract (sommario):
In most cases, fixed temperature heat detectors are used to detect fire in vehicles. The response parameter of such detectors is constant. The time of fire detection by a fire detector, as well as the probability of its false operation, are affected by heat flux from an internal combustion engine. This paper reports the development and investigation of an operational algorithm of the fixed-dynamic heat detectors with variable response parameters. Depending on the temperature influence exerted by engine operation modes, a given algorithm automatically changes a value of the minimal static response temperature of a detector, as well as value of the rate of rise in the temperature of its response. The experimental results showed that in the initial period of engine operation, the temperature change rate in the engine compartment fluctuates and is the largest. It can exceed 290 °С/min. However, regardless of the type of vehicle and the type of engine, when the temperature reaches technological, the temperature change rate would vary within small limits, approximately 30÷50 °С/min. The study results from the Simulink software package (USA) in the MATLAB programming environment (USA) confirm the effectiveness of the programmed operational algorithm of a thermal fire detector. The developed algorithm of a fire detector's operation makes it possible to detect the fire at an early stage and reduce the cases of the device's false response. The fire detector responded to both the maximal and dynamic components. As regards the maximal component, the proposed detector is triggered about 2.3 times faster than the classic maximal thermal fire detector. Detection of fire at an early stage makes it possible to quickly use the fire extinguishing system
31
Jang, Hyo-Yeon, e Cheol-Hong Hwang. "Obscuration Threshold Database Construction of Smoke Detectors for Various Combustibles". Sensors 20, n. 21 (4 novembre 2020): 6272. http://dx.doi.org/10.3390/s20216272.
Testo completoAbstract (sommario):
The obscuration thresholds for various smoke detectors and combustibles, required as an input parameter in fire simulation, were measured to predict the accurate activation time of detectors. One ionization detector and nine photoelectric detectors were selected. A fire detector evaluator, which can uniformly control the velocity and smoke concentration, was utilized. Filter paper, liquid fuels, and polymer pellets were employed as smoke-generation combustibles. The nominal obscuration thresholds of the considered detectors were 15 %/m, but the ionization detectors activated at approximately 40 %/m and 16 %/m, respectively, on applying filter paper and kerosene. In contrast, the reverse obscuration thresholds were found quantitatively according to the combustibles in the photoelectric detector. This phenomenon was caused by differences in the color of the smoke particles according to the combustibles, which is explained by single-scattering albedo (ratio of light scattering to light extinction). The obscuration thresholds for liquid fuels (kerosene, heptane and toluene) as well as fire types of polymer plastic pellets were also measured for several photoelectric detectors. A database of obscuration thresholds was thereby established according to the detector and combustible types, and it is expected to provide useful information for predicting more accurate detector activation time and required safe egress time (REST).
32
Kitazono, Yuhki, Kohei Miyata, Shota Nakashima, Li Feng Zhang e Serikawa Seiichi. "Development of Position Detector with Large Sensing Area Using Frosted Glass". Applied Mechanics and Materials 103 (settembre 2011): 600–605. http://dx.doi.org/10.4028/www.scientific.net/amm.103.600.
Testo completoAbstract (sommario):
This paper proposes a new position detector using frosted glass and four photo detectors. Four photo detectors are arranged under the four corners of the rough surface of frosted glass. When this sensor is irradiated by laser pointer, the light repeats reflection in the frosted glass and arrives at the photo detectors. The light intensity decreases by the increasing of distance between the photo detector and the irradiating point. Therefore, the distance between a photo detector and the irradiation point can be worked out from the output of the photo detectors. Thus, the light irradiation point can be derived from the distances with the four photo detectors. This sensor is low cost and has a large sensing area. In addition, this sensor also can be used as a pointing device because the movement of the light on the frosted glass can be judged.
33
Liang, Gongbo, Jesus Guerrero, Fengbo Zheng e Izzat Alsmadi. "Enhancing Neural Text Detector Robustness with μAttacking and RR-Training". Electronics 12, n. 8 (21 aprile 2023): 1948. http://dx.doi.org/10.3390/electronics12081948.
Testo completoAbstract (sommario):
With advanced neural network techniques, language models can generate content that looks genuinely created by humans. Such advanced progress benefits society in numerous ways. However, it may also bring us threats that we have not seen before. A neural text detector is a classification model that separates machine-generated text from human-written ones. Unfortunately, a pretrained neural text detector may be vulnerable to adversarial attack, aiming to fool the detector into making wrong classification decisions. Through this work, we propose μAttacking, a mutation-based general framework that can be used to evaluate the robustness of neural text detectors systematically. Our experiments demonstrate that μAttacking identifies the detector’s flaws effectively. Inspired by the insightful information revealed by μAttacking, we also propose an RR-training strategy, a straightforward but effective method to improve the robustness of neural text detectors through finetuning. Compared with the normal finetuning method, our experiments demonstrated that RR-training effectively increased the model robustness by up to 11.33% without increasing much effort when finetuning a neural text detector. We believe the μAttacking and RR-training are useful tools for developing and evaluating neural language models.
34
Ibragimov, Renat F., Yakov A. Kokorev, Anastasia P. Denisenko, Elena V. Ryabeva, Valery T. Samosadny e Hamza Hasnaoui. "Experimental determination of the induced activity in activation detectors of a complex geometric shape". Nuclear Energy and Technology 6, n. 3 (11 settembre 2020): 149–54. http://dx.doi.org/10.3897/nucet.6.57738.
Testo completoAbstract (sommario):
The paper presents the results of experimental determination of the induced activity in copper-/aluminum-based activation detectors when irradiated with neutrons with energies of about 14 MeV. The activation detectors were square-shaped metal plates with a thickness from 1.0 to 1.5 mm and a side size about 5.0 cm. These dimensions significantly exceed those of the detectors that are used in the research of high-intensity neutron fluxes. The detectors described in this work can be used for studying low-intensity neutron fluxes (with a flux density of up to 106 n/cm2∙s). It is shown that, when working with such detectors, it is possible to apply the usual methods for calculating the induced activity in thin activation detectors, with corrections that take into account the emerging features of the ‘neutron source - activation detector’ and ‘activation detector - secondary radiation detector’ geometries. The effects of absorption of primary and secondary radiation by the detector substance are also revealed. The Geant4 tools were used for calculating the geometric factors and theoretical induced activity. The study confirms the applicability of such activation detectors for solving the problem of determining the yield of neutrons with energies of about 14 MeV from a neutron generator target. The results of the experiments coincide, within the margin of error, with the results of simulations performed using the Geant4 tools.
35
KWON, HEESUNG, NASSER M. NASRABADI e PATTI GILLESPIE. "NONLINEAR CHEMICAL PLUME DETECTION USING KERNEL-BASED MATCHED SUBSPACE DETECTORS". International Journal of High Speed Electronics and Systems 17, n. 04 (dicembre 2007): 813–26. http://dx.doi.org/10.1142/s0129156407005004.
Testo completoAbstract (sommario):
In this paper, we compare several detection algorithms that are based on spectral matched (subspace) filters. Nonlinear (kernel) versions of these spectral matched (subspace) detectors are also discussed and their performance is compared with the linear versions. These kernel-based detectors exploit the nonlinear correlations between the spectral bands that are ignored by the conventional detectors. Several well-known matched detectors, such as matched subspace detector, orthogonal subspace detector, spectral matched filter and adaptive subspace detector (adaptive cosine estimator) are extended to their corresponding kernel versions by using the idea of kernel-based learning theory. In kernel-based detection algorithms the data is implicitly mapped into a high dimensional kernel feature space by a nonlinear mapping which is associated with a kernel function. The detection algorithm is then derived in the feature space which is kernelized in terms of the kernel functions in order to avoid explicit computation in the high dimensional feature space. Experimental results based on simulated toy-examples and real hyperspectral imagery shows that the kernel versions of these detectors outperform the conventional linear detectors.
36
Rybarczyk, R. Joseph, Alexandria E. D. Federick, Oleksandr Kokhan, Ryan Luckay e Giovanna Scarel. "Probing electromagnetic wave energy with an in-series assembly of thermoelectric devices". AIP Advances 12, n. 4 (1 aprile 2022): 045201. http://dx.doi.org/10.1063/5.0082749.
Testo completoAbstract (sommario):
We study the interaction of radio waves, microwaves, and infrared laser light of power P and period τ with a macroscopic thermoelectric (TEC) device-based detector and probe the energy Pτ as being the energy of these electromagnetic (EM) waves. Our detectors are in-series assemblies of TEC devices. We treat these detectors as equivalent to capacitors and/or inductors. The energy Pτ enables characterizing detector’s parameters, such as equivalent capacitance, inductance, resistance, responsivities, effective power, and efficiency. Through various scaling procedures, Pτ also aids in determining the power P of the EM waves. We compare the performance of our detectors with that of other TEC devices and with radio- and microwave-sensitive devices reported in the current literature, such as spin–orbit torque and spin–torque oscillator devices, heterojunction backward tunnel diodes, and Schottky diodes. We observe that the performance of our detectors is inferior. However, the order of magnitude of our detector’s parameters is in reasonable agreement with those of other TEC and non-TEC devices. We conclude that TEC devices can be used to detect radio waves and that Pτ effectively captures the energy of the EM waves. Considering Pτ as the EM wave’s energy offers a classical approach to the interaction of EM waves with matter in which photons are not involved. With the EM wave’s energy depending upon two variables (P and τ), a similar response could be produced by, e.g., radio waves and visible light, leading to interesting consequences that we briefly outline.
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MATSAS, GEORGE E. A., e DANIEL SUDARSKY. "UNRUH-DEWITT DETECTORS IN THE PRESENCE OF SCALAR SOURCES". Modern Physics Letters A 09, n. 36 (30 novembre 1994): 3325–30. http://dx.doi.org/10.1142/s0217732394003142.
Testo completoAbstract (sommario):
We analyze the response of Unruh-DeWitt detectors in the presence of inertial scalar sources. We show that, in general, a detector responds to the corresponding Coulomb field. However, in some cases, pure vacuum contributions can overwhelm the influence of the Coulomb field rendering the effect of the external source on the detector’s response arbitrarily small. We revisit in this context the celebrated question of whether uniformly accelerated observers can see the radiation coming from an inertial charge, and point out the present impediments to answering this question.
38
Krupiński, Michał, Grzegorz Bieszczad, Tomasz Sosnowski, Henryk Madura e Sławomir Gogler. "Non-Uniformity Correction in Microbolometer Array with Temperature Influence Compensation". Metrology and Measurement Systems 21, n. 4 (1 dicembre 2014): 709–18. http://dx.doi.org/10.2478/mms-2014-0050.
Testo completoAbstract (sommario):
Abstract In the article a non-uniformity correction method is presented which allows to compensate for the influence of detector’s temperature drift. For this purpose, dependency between output signal value and the temperature of the detector array was investigated. Additionally the influence of the temperature on the Offset and Gain coefficients was measured. Presented method utilizes estimated dependency between output signal of detectors and their temperature. In the presented method, the shutter is used for establishing signal reference. Thermoelectric cooler is used for changing the temperature of the detector array.
39
Abdulla, Karima, Abtisam A. Alakrout, Manal Omer e Samah Aghtisa. "EVALUATION STUDY OF LANTHANUM HALIDE DETECTORS (LABR3:CE , LACL3:CE, NAI(TL), (HPGE)". Scientific Journal of Applied Sciences of Sabratha University 3, n. 2 (27 settembre 2020): 42–52. http://dx.doi.org/10.47891/sabujas.v3i2.42-52.
Testo completoAbstract (sommario):
Through the use of thesources spectrums 22Na (S311.PH), 60Co (S297.PH), 133Ba (S295.PH), 137Cs (S296.PH) and 152Eu (S285.PH) the properties of Lanthanum Tri-Bromide (LaBr3:Ce) and Lanthanum Tri-Chloride (LaCl3:Ce) scintillation detectors were compared against Sodium Iodide (NaI(Tl)) scintillation and Hyper Pure Germanium (HPGe) semiconductor detectors. In all instances the HPGe detector was found to be superior, So, Hyper Pure Germanium detectors (HPGe) are outstanding devices for radioactivity spectroscopy. In addition the LaBr3:Ce and LaCl3:Ce detectors were always found to be superior to the NaI(Tl) detector.
40
Hou, Qingfeng, Tianning Wang, Rui Zhao, Jun Tang, Li Qin, Zongmin Ma e Jun Liu. "Fast time response detectors of alpha particles fabricated using CVD diamonds". Journal of Instrumentation 18, n. 06 (1 giugno 2023): T06012. http://dx.doi.org/10.1088/1748-0221/18/06/t06012.
Testo completoAbstract (sommario):
Abstract Diamond with extraordinary properties, such as fast response, and extremely high thermal conductivity, is an ideal choice for the next generation radiation detectors. In this paper, a radiation detector based on a single crystal CVD diamond (3 mm × 3 mm × 200 μm) with (100) orientation is proposed to detect α radiation. The detector employs gold films on the diamond as an electrical contact, and the origin-symmetric current-voltage characteristics demonstrated excellent Ohmic contact behavior. At an electric field of 0.4 V/μm, a current dark value of 4 nA was measured. The detector's pulse speed was tested using 5.486 MeV 241Am sources. The time response of the detector to α particles is fast, with a rise time of 260 ps, a fall time of 650 ps, and a pulse width of 1.6 ns. These findings indicate that the detector can be used as a sensor for α radiation.
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Hatsui, Takaki, e Heinz Graafsma. "X-ray imaging detectors for synchrotron and XFEL sources". IUCrJ 2, n. 3 (10 aprile 2015): 371–83. http://dx.doi.org/10.1107/s205225251500010x.
Testo completoAbstract (sommario):
Current trends for X-ray imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve their performance, especially for higher spatial resolution at higher count rates with higher frame rates. Recent developments for X-ray free-electron laser (XFEL) experiments provide high-frame-rate integrating detectors with both high sensitivity and high peak signal. Similar performance improvements are sought in monolithic detectors. The monolithic approach also offers a lower noise floor, which is required for the detection of soft X-ray photons. The link between technology development and detector performance is described briefly in the context of potential future capabilities for X-ray imaging detectors.
42
Liou, Juin Jie, Hao-Tse Hsiao, I.-Cheng Yao, Jia-Syun Jheng e Chu-Hsuan Lin. "The Superior Responsivity Enhancement of Thin-Film Ge Photodetectors by AuNP Coatings". Coatings 10, n. 8 (29 luglio 2020): 739. http://dx.doi.org/10.3390/coatings10080739.
Testo completoAbstract (sommario):
We have tried to improve the responsivity of germanium-based thin-film photodetectors. It has been shown that applying a mechanical strain to the detector led to a 46.6% enhancement on the 1550 nm detection. This improvement is better than the 1310 nm case, because the bandgap shrinkage is more beneficial to the small-energy photon detection. The AuNP coating is even more attractive for responsivity enhancement of thin-film germanium (Ge) detectors. The responsivity enhancement due to the AuNP deposition is as high as 89% and 47%, for the 1310 nm and 1550 nm detections, respectively. To the best of our knowledge, this is the best responsivity enhancement for the thin-film Ge detectors reported to date.
43
Giffen, William J., Elizabet Haro, Mark R. Lehto e Jason D. Papastavrou. "Use and Misuse of Smoke Detectors in Residential Areas". Perceptual and Motor Skills 82, n. 3_suppl (giugno 1996): 1211–22. http://dx.doi.org/10.2466/pms.1996.82.3c.1211.
Testo completoAbstract (sommario):
This study examined the use and misuse of home smoke detectors in three cities in the United States: Dayton, Ohio, Union City, New Jersey, and San Francisco, California. A sample of 300 households, 100 in each city, were reached in telephone interviews which were concluded with a request to test the smoke detector. For the sample, 86% had a smoke detector, and 73% of those smoke detectors were working. Neither the presence of children or whether the smoke detector was preinstalled or purchased and installed by the homeowner were associated with the likelihood of owning a smoke detector or its operating condition. However, ownership varied between cities; 98% of respondents owned detectors in Dayton, OH compared to 72% in San Francisco, CA. Belief that smoke detectors were in good operating condition was strongly correlated with their actual state. Whether the detector was maintained in-house and the interaction between city and whether it was purchased by the resident were also significantly related to whether a smoke detector was working.
44
García-Martín, Álvaro, Juan SanMiguel e José Martínez. "Coarse-to-Fine Adaptive People Detection for Video Sequences by Maximizing Mutual Information †". Sensors 19, n. 1 (20 dicembre 2018): 4. http://dx.doi.org/10.3390/s19010004.
Testo completoAbstract (sommario):
Applying people detectors to unseen data is challenging since patterns distributions, such as viewpoints, motion, poses, backgrounds, occlusions and people sizes, may significantly differ from the ones of the training dataset. In this paper, we propose a coarse-to-fine framework to adapt frame by frame people detectors during runtime classification, without requiring any additional manually labeled ground truth apart from the offline training of the detection model. Such adaptation make use of multiple detectors mutual information, i.e., similarities and dissimilarities of detectors estimated and agreed by pair-wise correlating their outputs. Globally, the proposed adaptation discriminates between relevant instants in a video sequence, i.e., identifies the representative frames for an adaptation of the system. Locally, the proposed adaptation identifies the best configuration (i.e., detection threshold) of each detector under analysis, maximizing the mutual information to obtain the detection threshold of each detector. The proposed coarse-to-fine approach does not require training the detectors for each new scenario and uses standard people detector outputs, i.e., bounding boxes. The experimental results demonstrate that the proposed approach outperforms state-of-the-art detectors whose optimal threshold configurations are previously determined and fixed from offline training data.
45
Yang, Zhekai, e Yiran Dong. "Muon rate measurement under different thicknesses of Pb". Journal of Physics: Conference Series 2381, n. 1 (1 dicembre 2022): 012077. http://dx.doi.org/10.1088/1742-6596/2381/1/012077.
Testo completoAbstract (sommario):
Abstract The major purpose of this paper is to analyze the rate of events under the different thicknesses of Pb on the top of two cosmic watch desktop muon detectors. The desktop muon detector is a simple, easy-built, and cheap cosmic ray muon detector. Using these detectors, the researchers experimented with different altitudes [2]. In this work, we concluded how the thickness of Pb above the detectors influences the rate of the muon. We placed one-on-top of another detector and changed the thickness of Pb above them. Using the python program, we analyzed a large number of data collected by the two desktop muon detectors systematically. We analyzed the relationship between the muon rate with the thickness and calculated the parameters. The result shows muon rate decreases exponentially as thickness increasing.
46
KARAHAN, Sümeye Nur, e Aykut KALAYCIOĞLU. "Utilization of deep learning architectures for MIMO detection". Communications Faculty of Sciences University of Ankara Series A2-A3 Physical Sciences and Engineering 64, n. 2 (30 dicembre 2022): 81–94. http://dx.doi.org/10.33769/aupse.1140193.
Testo completoAbstract (sommario):
Applications of deep learning in communications systems are becoming popular today with their powerful solutions to complex problems. This study considers the utilization of deep learning detectors for small-scale multiple-input multiple-output systems. Deep neural network, long short-term memory, and one-dimenisonal convolutional neural network architectures are discussed and the bit error rate performances of these deep learning based detectors are compared with the optimal maximum likelihood and sub-optimal minimum mean square error detectors. Simulation results show that the deep neural network architecture has the best detection performance among the discussed deep learning detectors and may outperform the sub-optimal minimum mean square error detector. For small-scale multiple-input multiple-output systems, the performance of the deep learning based detector is close to that of the optimal detector.
47
Gazivoda, Marko, Dinko Oletić e Vedran Bilas. "Features and Always-On Wake-Up Detectors for Sparse Acoustic Event Detection". Electronics 11, n. 3 (6 febbraio 2022): 478. http://dx.doi.org/10.3390/electronics11030478.
Testo completoAbstract (sommario):
The need to understand and manage our surroundings has led to increased interest in sensor networks for the continuous monitoring of events and processes of interest. To reduce the power consumption required for continuous monitoring, dedicated always-on wake-up detectors have been designed, with an emphasis on their low power consumption, simple and robust design, and reliable and accurate detection. An especially interesting application of these wake-up detectors is in detecting acoustic signals. In this paper, we present a study on the features and detectors applicable for the detection of sporadic acoustic events. We perform a state-of-the-art acoustic detector analysis, grouping the detectors based on the features they utilize and their implementations. This analysis shows that acoustic wake-up detectors predominantly utilize spectro-temporal (56%) and temporal features (36%). Following the state-of-the-art analysis, we select two detector architecture candidates for a case study on passing motor vehicle detection. We utilize our previously developed spectro-temporal decomposition detector and develop a novel level-crossing rate detector. The results of the case study shows that the proposed level-crossing rate detector has lower component count (44 compared to 70) and power consumption (9.1 µW compared to 34.6 µW) and is an optimal solution for SNRs over 0 dB.
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Kim, Sungjoon, Vikas Berry, Jessica Metcalfe e Anirudha V. Sumant. "Thin film charged particle detectors". Journal of Instrumentation 18, n. 07 (1 luglio 2023): P07047. http://dx.doi.org/10.1088/1748-0221/18/07/p07047.
Testo completoAbstract (sommario):
Abstract Silicon tracking detectors have grown to cover larger surface areas up to hundreds of square meters, and are even taking over other sub-detectors, such as calorimeters. However, further improvements in tracking detector performance are more likely to arise from the ability to make a low mass detector comprised of a high ratio of active sensor to inactive materials, where dead materials include electrical services, cooling, mechanical supports, etc. In addition, the cost and time to build these detectors is currently large. Therefore, advancements in the fundamental technology of tracking detectors may need to look at a more transformative approach that enables extremely large area coverage with minimal dead material and is easier and faster to build. The advancement of thin film fabrication techniques has the potential to revolutionize the next-to-next generation of particle detector experiments. Some thin film deposition techniques have already been developed and widely used in the industry to make LED screens for TVs and monitors. If large area thin film detectors on the order of several square meters can be fabricated with similar performance as current silicon technologies, they could be used in future particle physics experiments. This paper aims to review the key fundamental performance criteria of existing silicon detectors and past research to use thin films and other semi-conductor materials as particle detectors in order to explore the important considerations and challenges to pursue thin film detectors.
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Kawamura, Koji, Kazumasa Miyazawa e Lloyd Kent. "The Past, Present and Future in Tube- and Paper-Based Colorimetric Gas Detectors". AppliedChem 1, n. 1 (18 agosto 2021): 14–40. http://dx.doi.org/10.3390/appliedchem1010003.
Testo completoAbstract (sommario):
Colorimetric gas detectors have been widely applied in many fields such as environmental sciences, industrial hygiene, process control, forensic science and indoor air quality monitoring. They have a history of about 100 years and include devices such as gas detector tubes and paper-based gas detectors. The sensitivity and selectivity of the colorimetric gas detector are relatively high compared to other types of gas detectors such as semiconductor, catalytic combustion and electrochemical gas detectors. Detection of gas concentration can be performed by the naked eye in some colorimetric gas detectors. These methods do not require an electrical power source and are simple, so they are suitable for field operations. This review introduces the history and provides a general overview of the development in the research of colorimetric gas detectors. Recently, the sensitivity and selectivity of colorimetric gas detectors have improved. New materials such as enzymes or particles with a large surface area have been utilized to improve selectivity and sensitivity. Moreover, new gas detectors without toxic materials have been developed to reduce the environmental load. At present, there is a rapid development of IoT sensors in many industrial fields, which might extend the applications of colorimetric gas detectors in the near future.
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Deng, Fang Yi, Xin She Wu e Yuan Fang Li. "In Modulating Ferroelectric Uncooled Infrared Focal Plane Detector". Applied Mechanics and Materials 455 (novembre 2013): 474–79. http://dx.doi.org/10.4028/www.scientific.net/amm.455.474.
Testo completoAbstract (sommario):
Aiming at detecting rate and frame rate problems restricting the development of ferroelectric detector technology, puts forward a new design method of ferroelectric ferroelectric detectors -- detector modulation. Improvement principle and structure of the original ferroelectric detectors, and summarizes the technical features of this device.