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Izumi, Yoshihiro y Yasukuni Yamane. "Solid-State X-Ray Imagers". MRS Bulletin 27, n.º 11 (noviembre de 2002): 889–93. http://dx.doi.org/10.1557/mrs2002.278.
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AbstractNew solid-state x-ray imagers known as digital flat-panel x-ray detectors are about to be launched in the field of medical diagnostics. The combination of active-matrix technologies developed for active-matrix liquid-crystal displays and x-ray detection materials constitutes the basis of the detectors. Recently, two kinds of direct-conversion detectors have been developed in order to improve their performance. One is a detector using a thick x-ray photoconductor (∼1 mm) made of amorphous selenium, and the other is a novel hybrid panel detector using an x-ray photoconductor made of polycrystalline Cd(Zn)Te. As a result, excellent resolution and good linear sensitivity have been achieved. These detectors have great promise as next-generation digital imaging systems for fluoroscopy and radiography.
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Ebadi, Reza, Mason C. Marshall, David F. Phillips, Johannes Cremer, Tao Zhou, Michael Titze, Pauli Kehayias et al. "Directional detection of dark matter using solid-state quantum sensing". AVS Quantum Science 4, n.º 4 (diciembre de 2022): 044701. http://dx.doi.org/10.1116/5.0117301.
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Next-generation dark matter (DM) detectors searching for weakly interacting massive particles (WIMPs) will be sensitive to coherent scattering from solar neutrinos, demanding an efficient background-signal discrimination tool. Directional detectors improve sensitivity to WIMP DM despite the irreducible neutrino background. Wide-bandgap semiconductors offer a path to directional detection in a high-density target material. A detector of this type operates in a hybrid mode. The WIMP or neutrino-induced nuclear recoil is detected using real-time charge, phonon, or photon collection. The directional signal, however, is imprinted as a durable sub-micron damage track in the lattice structure. This directional signal can be read out by a variety of atomic physics techniques, from point defect quantum sensing to x-ray microscopy. In this Review, we present the detector principle as well as the status of the experimental techniques required for directional readout of nuclear recoil tracks. Specifically, we focus on diamond as a target material; it is both a leading platform for emerging quantum technologies and a promising component of next-generation semiconductor electronics. Based on the development and demonstration of directional readout in diamond over the next decade, a future WIMP detector will leverage or motivate advances in multiple disciplines toward precision dark matter and neutrino physics.
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Zhang, Lei, Chenkai Qiao, Jingjun Zhu, Yu Liu, Yulu Yan, Shin-Ted Lin, Shukui Liu, Changjian Tang y Haoyang Xing. "Preparation of Large Volume Solid Argon Crystal and Its Feasibility Test as a Scintillation Material". Crystals 12, n.º 10 (7 de octubre de 2022): 1416. http://dx.doi.org/10.3390/cryst12101416.
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An important background to the liquid argon detectors is that they are caused by the diffusion of radioactive isotopes in a scintillator (liquid phase). This radioactive isotope is produced in argon’s surrounding devices, such as circulation pipelines and liquid argon containers. The solid argon as a scintillation material in the detector can inhibit the diffusion and drift of radioactive isotopes in a solid phase scintillator. Additionally, the structure of a solid argon detector is simple and reduces the total source of radioactive background. In the CDEX-300 detection system, solid argon could substitute for liquid argon as the veto detector, preventing radioactive isotopes drifting to the central main detector (HPGe detectors array) surface to reduce backgrounds. Therefore, solid argon has great potential in the experiments since it is especially helpful to get the lower background in a larger active volume than liquid argon required in those low background detection experiments. This work introduces the preparation process and device of the large volume transparent crystalline argon, the acquisition of scintillation light, and the pulse amplitude spectrum of 137Cs obtained from a prototype detector of transparent solid argon crystal. The results show that the scheme proposed in this study can successfully produce a large volume transparent crystalline argon detector, the scintillation light signals can be effectively obtained from the solid argon scintillator, and the corresponding pulse amplitude spectrum is given. This work indicates that it is feasible to develop a solid argon crystal scintillation detector by using our approach.
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Nayak, A., M. K. Parida, V. Kumar y G. Prasanna. "Investigation of thermal neutron detection efficiency of Boron Carbide converter material using GEANT4 simulation for different types of detector configurations". Journal of Instrumentation 17, n.º 07 (1 de julio de 2022): P07012. http://dx.doi.org/10.1088/1748-0221/17/07/p07012.
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Abstract A lot of advancement in the field of semiconductors has made it possible to design a solid state neutron detector. They are small in size and compact, have economical bulk fabrications, require low power for their operation. Hence it can act as a plausible alternative to traditional neutron detector such as gas filled and scintillation detectors. It has been observed that many factors like the choice of converter material, LLD settings and geometrical configurations have an impact on the thermal neutron detection efficiency of solid state neutron detector design. Therefore in the present research work, a systematic GEANT4 simulation have been performed on estimating the simulated thermal neutron detection efficiency (η) for five different solid state detector geometrical configurations design with Boron Carbide (10B4C) as a converter material. These detectors geometry configurations designs are planar, rectangular parallel trenches, cylindrical perforation, stack and spherical (single and multi-layer). The objective of the simulations was to obtain critical geometrical features for which the efficiency reaches the maximum value, of the given detector configurations. The influence of the different enrichment levels of 10B (20% to 80%) in Boron Carbide and different Low-Level Discriminator (LLD) value setting (from 100 keV to 700 keV) on the simulated thermal neutron detection efficiency was also investigated. Finally, the simulated multi channel analyzer spectra or in other words histoplots were obtained for all the detector configurations.
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Chatzakis, J., I. Rigakis, S. M. Hassan, E. L. Clark y P. Lee. "Detection of pulsed neutrons with solid-state electronics". International Journal of Modern Physics: Conference Series 44 (enero de 2016): 1660229. http://dx.doi.org/10.1142/s2010194516602295.
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Measurements of the spatial and time-resolved characteristics of pulsed neutron sources require large area detection materials and fast circuitry that can process the electronic pulses readout from the active region of the detector. In this paper, we present a solid-state detector based on the nuclear activation of materials by neutrons, and the detection of the secondary particle emission of the generated radionuclides’ decay. The detector utilizes a microcontroller that communicates using a modified SPI protocol. A solid-state, pulse shaping filter follows a charge amplifier, and it is designed as an inexpensive, low-noise solution for measuring pulses measured by a digital counter. An imaging detector can also be made by using an array of these detectors. The system can communicate with an interface unit and pass an image to a personal computer.
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Zhang, K., G. Rosenbaum y G. Bunker. "Energy-Resolving X-ray Fluorescence Detection Using Synthetic Multilayers". Journal of Synchrotron Radiation 5, n.º 4 (1 de julio de 1998): 1227–34. http://dx.doi.org/10.1107/s0909049597019535.
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The potential of synthetic multilayers for energy-resolving the X-ray fluorescence in X-ray absorption fine structure (XAFS) experiments is discussed. Two detection systems, one using curved multilayers and the other using graded multilayers to select X-ray fluorescence photons, have been designed to cover a wide energy range with a usefully large solid angle. Such a detector will be more advantageous than the barrel-like crystal-array detector because of the unique properties of synthetic multilayers, such as larger horizontal acceptance angles and bandwidth. In addition, the detector should be much simpler to construct and readily accommodates energy changes, especially the detector using graded multilayers. Comparison of the multilayer array detector with conventional detectors, such as ionization chambers and conventional 13-element Ge detectors, shows that the proposed system will be superior, particularly with the increased photon fluxes available from insertion devices and with decreased sample concentration, since this detection system eliminates the `bad' photons before they enter any X-ray detector. Consequently, the X-ray detector proper for this system does not suffer from the incident-count-rate bottleneck common to current X-ray fluorescence detectors with energy resolution by signal processing. Thus, this new fluorescence detection system will provide tremendous opportunities for XAFS measurements on dilute systems, such as biological systems, at third-generation synchrotron sources.
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Zaluzec, Nestor J. "Detector Solid Angle Formulas for Use in X-Ray Energy Dispersive Spectrometry". Microscopy and Microanalysis 15, n.º 2 (16 de marzo de 2009): 93–98. http://dx.doi.org/10.1017/s1431927609090217.
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AbstractWith the advent of silicon drift X-ray detectors, a range of new geometries has become possible in electron optical columns. Because of their compact size, these detectors can potentially achieve high geometrical collection efficiencies; however, using traditional approximations detector solid angle calculations rapidly break down and at times can yield nonphysical values. In this article we present generalized formulas that can be used to calculate the variation in detection solid angle for contemporary Si(Li) as well as new silicon drift configurations.
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Yuan, Jing, Panagiotis Barmpoutis y Tania Stathaki. "Pedestrian Detection Using Integrated Aggregate Channel Features and Multitask Cascaded Convolutional Neural-Network-Based Face Detectors". Sensors 22, n.º 9 (7 de mayo de 2022): 3568. http://dx.doi.org/10.3390/s22093568.
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Pedestrian detection is a challenging task, mainly owing to the numerous appearances of human bodies. Modern detectors extract representative features via the deep neural network; however, they usually require a large training set and high-performance GPUs. For these cases, we propose a novel human detection approach that integrates a pretrained face detector based on multitask cascaded convolutional neural networks and a traditional pedestrian detector based on aggregate channel features via a score combination module. The proposed detector is a promising approach that can be used to handle pedestrian detection with limited datasets and computational resources. The proposed detector is investigated comprehensively in terms of parameter choices to optimize its performance. The robustness of the proposed detector in terms of the training set, test set, and threshold is observed via tests and cross dataset validations on various pedestrian datasets, including the INRIA, part of the ETHZ, and the Caltech and Citypersons datasets. Experiments have proved that this integrated detector yields a significant increase in recall and a decrease in the log average miss rate compared with sole use of the traditional pedestrian detector. At the same time, the proposed method achieves a comparable performance to FRCNN on the INRIA test set compared with sole use of the Aggregated Channel Features detector.
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Radtke, J. L. y D. W. Beard. "A New Position Sensitive Detector for X-Ray Diffractometry". Advances in X-ray Analysis 36 (1992): 617–22. http://dx.doi.org/10.1154/s0376030800019261.
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AbstractPosition sensitive detectors provide efficient X-ray detection over large solid angles; this capability has revolutionized X-ray diffractometry by reducing data collection time. This paper describes testing of a new single-axis position sensitive detector designed to locate 0.6-2 Angstrom X-rays. Dead time, quantum efficiency, energy resolution, and spatial resolution were measured. Standard powder diffraction patterns were observed with the detector, and data sets are presented. The impact of detector performance parameters on diffraction experiments is discussed.
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Lowdon, Matthew, Peter G. Martin, M. W. J. Hubbard, M. P. Taggart, Dean T. Connor, Yannick Verbelen, P. J. Sellin y Thomas B. Scott. "Evaluation of Scintillator Detection Materials for Application within Airborne Environmental Radiation Monitoring". Sensors 19, n.º 18 (4 de septiembre de 2019): 3828. http://dx.doi.org/10.3390/s19183828.
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In response to the Fukushima Daiichi Nuclear Power Plant accident, there has occurred the unabated growth in the number of airborne platforms developed to perform radiation mapping—each utilising various designs of a low-altitude uncrewed aerial vehicle. Alongside the associated advancements in the airborne system transporting the radiation detection payload, from the earliest radiological analyses performed using gas-filled Geiger-Muller tube detectors, modern radiation detection and mapping platforms are now based near-exclusively on solid-state scintillator detectors. With numerous varieties of such light-emitting crystalline materials now in existence, this combined desk and computational modelling study sought to evaluate the best-available detector material compatible with the requirements for low-altitude autonomous radiation detection, localisation and subsequent high spatial-resolution mapping of both naturally occurring and anthropogenically-derived radionuclides. The ideal geometry of such detector materials is also evaluated. While NaI and CsI (both elementally doped) are (and will likely remain) the mainstays of radiation detection, LaBr3 scintillation detectors were determined to possess not only a greater sensitivity to incident gamma-ray radiation, but also a far superior spectral (energy) resolution over existing and other potentially deployable detector materials. Combined with their current competitive cost, an array of three such composition cylindrical detectors were determined to provide the best means of detecting and discriminating the various incident gamma-rays.
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Nicholls, A. W. "A comparison of two windowless x-ray detector designs on VG HB501 STEMs". Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 672–73. http://dx.doi.org/10.1017/s0424820100105424.
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Windowless X-ray detectors are routinely used on VG HB501 STEMs allowing detection of all elements from B upwards (fig 1). The original design for the HB501 built by Link Analytical had a theoretical solid angle of 0.077sr but recently a new design has appeared with a solid angle of 0.181sr. In order to compare these two designs it would be useful to develop a test that could be carried out on the microscope column that would accurately characterise the performance of the detector in the low energy range (<1keV) as well as at higher energies. Recently there has been much interest in characterising X-ray detector microscope systems using the peak to background (P' B) ratio from specially prepared evaporated Cr films. As an extension to this method this type of specimen has-been used to look at the ratio of effective detector solid angles and also the low energy area by comparing CrK to CrL intensities in order to fully characterise the detectors on VG HB501 STEMs.
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Yang, F., X. H. Ma, H. K. Chen, T. L. Chen, S. W. Cui, Danzengluobu, W. Gao et al. "Correlation between thermal neutrons and soil moisture measured by ENDA". Journal of Instrumentation 18, n.º 05 (1 de mayo de 2023): P05020. http://dx.doi.org/10.1088/1748-0221/18/05/p05020.
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Abstract Hadrons are the “skeleton” of extensive air shower (EAS). They possess favorable information concerning composition and energy of cosmic ray. Thermal neutrons generated by the EAS hadrons in the ground as well as charged particles in EAS front plane can be detected by Electron-Neutron detector (EN-detector). A prototype of EN-Detector Array (ENDA), ENDA-16 was built at Large High Altitude Air Shower Observatory (LHAASO) to test its performance of detection of cosmic ray composition and energy spectrum. It has been proved in former work that there is a decrease of thermal neutrons detected in rainy season. For quantitative evaluation of influence of soil moisture on thermal neutrons, at the center of ENDA-16, five soil moisture meters are installed to record soil moisture. Negative correlation between thermal neutron counting rate and soil moisture is obtained. Moreover, it is demonstrated that a soil depth 0.5 m over the soil moisture sensor is enough for monitoring negative correlation between thermal neutron counting rate and soil moisture. The results provide us a method to correct the experimental data during the rainy season so as to reduce systematic uncertainty of thermal neutron measurement in the ENDA experiment.
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Krivanek, Ondrej L. "Progress in parallel-detection electron energy loss spectroscopy". Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 660–61. http://dx.doi.org/10.1017/s0424820100105369.
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Parallel-detection electron energy loss spectrometers improve the detection efficiency by several hundred times compared to the traditional serial-detection spectrometers, but they have their own set of difficulties, such as the limited dynamic range of solid state detectors, the possibility of stray reflections of the intense zero loss beam giving rise to spurious background, and channel-to-channel gain variation. Fortunately, none of these difficulties is turning out to be insoluble. Here we report on improvements of the Gatan 666 parallel detection electron spectrometer in the areas of increasing the dynamic range of the detector, and in eliminating stray reflections.The increase in the dynamic range of the detector was needed especially for low energy losses (high spectral intensities), which usually saturated the detector even at the minimum acquisition time of 12 msecs. Accordingly, we have developed an electron attenuator which uses a magnetic dipole to sweep the spectrum across the detector perpendicular to the dispersion direction (Fig. 1).
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Qiu, Shi, Hao Hu, Jun Peng Liu, Xiang Hui Lv, Xiang Li Wang y Wen Jie Li. "A Kind of Land Form Detector for Loose and Soft Sandy Soil Milling-Planing and Collecting Device Machinery". Advanced Materials Research 328-330 (septiembre de 2011): 1772–77. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.1772.
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In a Certain Mining Engineering, it’s Needed to Collect the Ore Bearing Sandy Soil with Certain Thickness from the Ground Surface. in Order to Realize Accurate Collection, it’s Needed to Control the Collecting Thickness Strictly. the Application of Contacting Type Landform Detecting Method in the Engineering Machinery Was Discussed, and a Kind of Mechanical Contacting Landform Detector Was Developed for the Alluvium Landform of Mining Area in Gobi with Loose, Rough and Uneven Ground Surface. the Landform of Soft Sandy Soil Can Be Detected by Controlling the Contact Pressure between the Depth Wheel of the Detector and the Ground Surface. with the Use of PID Control Technology with Wave Filtering, the Real-Time Detection Accuracy of the Detector for Mixed Sandy Soil Ground Surface Reaches ± 3mm. this Detector Is Specially Used for Milling, Planing and Collecting Device, Achieving Uniform Thickness Collection of Ore Bearing Sandy Soil in Rolling Topography Condition.
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Zhang, Junqing, Rujing Wang, Zhou Jin, Hongyan Guo, Yi Liu, Yongjia Chang, Jiangning Chen, Mengya Li y Xiangyu Chen. "Development of On-Site Rapid Detection Device for Soil Macronutrients Based on Capillary Electrophoresis and Capacitively Coupled Contactless Conductivity Detection (C4D) Method". Chemosensors 10, n.º 2 (15 de febrero de 2022): 84. http://dx.doi.org/10.3390/chemosensors10020084.
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The acquisition of nutrient data on a precise scale has played a vital role in nutrient management processes for soils. However, the lack of rapid precise and multi-index detection techniques for soil macronutrient contents hinders both rational fertilization and cost reduction. In this paper, a rapid detection method and device were devised, combining capillary electrophoresis (CE) and capacitively coupled contactless conductivity detection (C4D), and presented to detect macronutrient contents of soil. The device consisted of a capillary channel, C4D detector, high-voltage system, etc. It separated macronutrient ions using capillary electrophoresis and then measured the ion concentration based on the C4D principle. Lime concretion black soil samples from a complete field were collected and detected. NO3−, NH4+, H2PO4− and K+ in sample solutions could be detected in 5 min with relative standard deviations (RSDs) from 1.0 to 7.51%. The injection voltage was set to 10 kV for 5 s, and the separation voltage was set to 14 kV. This demonstrated the excellent performance of the C4D device on the detection of soil macronutrients, which could help to guide fertilization operations more effectively.
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Fratelli, Ilaria, Andrea Ciavatti, Enrico Zanazzi, Laura Basiricò, Massimo Chiari, Laura Fabbri, John E. Anthony, Alberto Quaranta y Beatrice Fraboni. "Direct detection of 5-MeV protons by flexible organic thin-film devices". Science Advances 7, n.º 16 (abril de 2021): eabf4462. http://dx.doi.org/10.1126/sciadv.abf4462.
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The direct detection of 5-MeV protons by flexible organic detectors based on thin films is here demonstrated. The organic devices act as a solid-state detector, in which the energy released by the protons within the active layer of the sensor is converted into an electrical current. These sensors can quantitatively and reliably measure the dose of protons impinging on the sensor both in real time and in integration mode. This study shows how to detect and exploit the energy absorbed both by the organic semiconducting layer and by the plastic substrate, allowing to extrapolate information on the present and past irradiation of the detector. The measured sensitivity, S = (5.15 ± 0.13) pC Gy−1, and limit of detection, LOD = (30 ± 6) cGy s−1, of the here proposed detectors assess their efficacy and their potential as proton dosimeters in several fields of application, such as in medical proton therapy.
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Ryzhikov, Vladimir D., Sergei V. Naydenov, Thierry Pochet, Gennadiy M. Onyshchenko, Leonid A. Piven y Craig F. Smith. "Advanced Multilayer Composite Heavy-Oxide Scintillator Detectors for High Efficiency Fast Neutron Detection". EPJ Web of Conferences 170 (2018): 07010. http://dx.doi.org/10.1051/epjconf/201817007010.
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We have developed and evaluated a new approach to fast neutron and neutron-gamma detection based on large-area multilayer composite heterogeneous detection media consisting of dispersed granules of small-crystalline scintillators contained in a transparent organic (plastic) matrix. Layers of the composite material are alternated with layers of transparent plastic scintillator material serving as light guides. The resulting detection medium – designated as ZEBRA – serves as both an active neutron converter and a detection scintillator which is designed to detect both neutrons and gamma-quanta. The composite layers of the ZEBRA detector consist of small heavy-oxide scintillators in the form of granules of crystalline BGO, GSO, ZWO, PWO and other materials. We have produced and tested the ZEBRA detector of sizes 100x100x41 mm and greater, and determined that they have very high efficiency of fast neutron detection (up to 49% or greater), comparable to that which can be achieved by large sized heavy-oxide single crystals of about Ø40x80 cm3 volume. We have also studied the sensitivity variation to fast neutron detection by using different types of multilayer ZEBRA detectors of 100 cm2 surface area and 41 mm thickness (with a detector weight of about 1 kg) and found it to be comparable to the sensitivity of a 3He-detector representing a total cross-section of about 2000 cm2 (with a weight of detector, including its plastic moderator, of about 120 kg). The measured count rate in response to a fast neutron source of 252Cf at 2 m for the ZEBRA-GSO detector of size 100x100x41 mm3 was 2.84 cps/ng, and this count rate can be doubled by increasing the detector height (and area) up to 200x100 mm2. In summary, the ZEBRA detectors represent a new type of high efficiency and low cost solid-state neutron detector that can be used for stationary neutron/gamma portals. They may represent an interesting alternative to expensive, bulky gas counters based on 3He or 10B neutron detection technologies.
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Al Oraini, Dalal. "Calibration of the Absolute Efficiency of Well-Type NaI(Tl) Scintillation Detector in 0.121–1.408 MeV Energy Range". Science and Technology of Nuclear Installations 2018 (2018): 1–6. http://dx.doi.org/10.1155/2018/6432380.
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Well-type NaI(Tl) detectors are beneficial for low-level photon activity measurements because of the near 4π solid angle that can be gained with them. The detection efficiency can differ with the source-to-detector system geometries, the absorption of the photon in the detector material, and attenuation layers in front of the detector face. For these purposes, the absolute efficiency and the coincidence corrections of the well-type sodium iodide detector have been measured at 0.121–1.408 MeV energy range (obtained from 152Eu, 137Cs, and 60Co radioactive isotopes). The covenant between the experimental (present work) and the published theoretical values is good, with the high discrepancies being less than 1%.
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Prusti, Banchhanidhi y Manab Chakravarty. "An electron-rich small AIEgen as a solid platform for the selective and ultrasensitive on-site visual detection of TNT in the solid, solution and vapor states". Analyst 145, n.º 5 (2020): 1687–94. http://dx.doi.org/10.1039/c9an02334h.
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A simple trimethoxybenzene-linked anthracenyl π-conjugate is developed for the ultra-sensitive and selective detection of TNT in solid, liquid and vapor phases. The TNT could also be detected in the field soil.
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Smith, G. D. W., A. Cerezo, T. J. Godfrey, R. Setna, J. M. Hyde y S. J. Sijbrandij. "Recent developments in position-sensitive atom-probe microanalysis". Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 828–29. http://dx.doi.org/10.1017/s0424820100171870.
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The difficulties associated with the aperture geometry of the conventional atom probe have been overcome by the introduction of a new generation of wide-angle, single-atom sensitivity, positionsensitive detectors. With the aid of such detectors, it is now possible to map the locations and identitiesof atoms over regions of solid surface up to 50 nm in diameter. The nanometer-scale chemistry of successive atomic layers can be investigated during the process of field evaporation. We therefore have the new and exciting ability to investigate the atomic-scale chemistry of solids in three dimensions. The first three-dimensional atom probe is the PoSAP (Position Sensitive Atom Probe), developed at Oxford by Cerezo and Smith. In this instrument, position sensing is carried out by means of a wedge-and-strip anode assembly, located directly behind the double microchannel plate used for primary ion detection and time of flight measurement. The detector readout functions in serial mode. Only one ioncan be successfully detected and identified for each evaporation pulse which is applied to the specimen
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Markoglou, Anastasios N., Eleftheria D. Bempelou, Konstantinos S. Liapis y Basil N. Ziogas. "Determination of Benzoylurea Insecticide Residues in Tomatoes by High-Performance Liquid Chromatography with Ultraviolet-Diode Array and Atmospheric Pressure Chemical Ionization-Mass Spectrometry Detection". Journal of AOAC INTERNATIONAL 90, n.º 5 (1 de septiembre de 2007): 1395–401. http://dx.doi.org/10.1093/jaoac/90.5.1395.
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Abstract A simple and sensitive method using high-performance liquid chromatography/mass spectrometry (LC/MS) was developed and validated for simultaneous determination of 5 benzoylurea insecticidesdiflubenzuron, triflumuron, teflubenzuron, lufenuron, and flufenoxuronin tomatoes. Residues were successfully separated on a C18 column by methanolwater isocratic elution. Detection was carried out by an ultraviolet diode array detector (UV-DAD) coupled with a quadrupole mass spectrometer, using atmospheric pressure chemical ionization (APCI) in negative-ion mode. The main ions were the deprotonated molecules [MH]<sup/> for triflumuron, and the anions formed by elimination of hydrofluoric acid [MHHF]<sup/> for diflubenzuron and flufenoxuron, and [M2HHF] for lufenuron and teflubenzuron. The calibration plots were linear for both detectors over the range 0.05 to 10 g/mL, and the method presented good quality parameters. The limits of detection for standard solutions were 0.0080.01 mg/L (equivalent to 0.080.1 ng injected) for both detectors, and the limits of quantification (LOQs) were approximately 10 times lower than national maximum residue levels (MRLs). Depending on the compound and the detector, the LOQ values ranged from 0.2 to 0.4 ng injected. The optimum LC-UV-DAD/APCI-MS conditions were applied to the analysis of benzoylureas in tomatoes. The obtained recoveries from fortified tomato samples (50 g), extracted with ethyl acetate and purified by solid-phase extraction on silica sorbent, were 88100 and 92.9105 for the UV-DAD and MS detectors, respectively, with precision values (relative standard deviations) of 2.911 and 3.714, respectively. The method was applied to 12 tomato samples from local markets, and diflubenzuron and lufenuron were detected in only one sample at concentrations lower than the MRLs. The results indicate that the developed LC/MS method is accurate, precise, and sensitive for quantitative and qualitative analysis at low levels of benzoylureas required by legislation.
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Stirzaker, R. J. y P. A. Hutchinson. "Irrigation controlled by a wetting front detector: field evaluation under sprinkler irrigation". Soil Research 43, n.º 8 (2005): 935. http://dx.doi.org/10.1071/sr05005.
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The accuracy of scheduling irrigation to turf by sprinkler was evaluated using a simple wetting front detector that automatically switched the water off after the wetting front had reached a prescribed depth in the soil. The detector consists of a funnel-shaped container that is buried in the soil. When a wetting front reaches the detector, the unsaturated flow lines are distorted so that the water content at the base of the funnel reaches saturation. The free water produced is detected electronically and this provides the signal to stop irrigation. The performance of the detector was evaluated over 38 consecutive irrigation events to test the theory that the velocity of a wetting front depends on the difference in water content ahead of and behind the front. The experimental data plotting the irrigation amount permitted by the wetting front detectors as a function of the soil water content before and after irrigation yielded a linear relationship with a slope of 0.95 and a correlation coefficient of 0.73. Thus, if the soil is dry before irrigation the front will move slowly and an irrigation of long duration will be permitted, with the converse applying to wet soil. Independent monitoring of soil water content showed that irrigation was, for the most part, scheduled accurately. Irrigation interval was the key variable to control. When the interval was too short then over irrigation occurred.
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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.º 3 (26 de enero de 2021): 568. http://dx.doi.org/10.3390/ma14030568.
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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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Gennari, Mara, Michèle Negre y Alessandro Cignetti. "Liquid Chromatographic Determination of Acifluorfen in Soil and Water". Journal of AOAC INTERNATIONAL 73, n.º 4 (1 de julio de 1990): 599–601. http://dx.doi.org/10.1093/jaoac/73.4.599.
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Abstract An analytical method based on the use of a liquid chromatograph equipped with a UV detector was developed for the determination of acifluorfen In soil and water. Acifluorfen was extracted from soil In methanol-0.10N NaOH (80 + 20 v/ v) and from water by partition with dlchloromethane. Solvent partitioning and solid-phase extraction were used to separate acifluorfen from major Interfering sample components. Average recoveries from soil at 1, 0.1, and 0.01 ppm fortification levels were 95.1 ± 3.4,92.6 ± 2.9, and 73.9 ± 3.0%, respectively. Recoveries from water spiked at levels from 0.01 to 1 ppm averaged 96.5 ± 5.4%. Method limits of detection were 0.006 ppm in soil and 0.003 ppm In water.
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Somlyo, Andrew P. "The Impact of Biological Microanalysis on Analytical Electron Microscopy". Microscopy and Microanalysis 4, S2 (julio de 1998): 170–71. http://dx.doi.org/10.1017/s1431927600020973.
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Advances in energy-dispersive detector technology were largely responsible for electron probe microanalysis (EPMA) becoming a valuable tool for biologists, while development of EPMA received much impetus from the special needs of biological research. Solid-state energy-dispersive detectors placed in close proximity to specimens in transmission electron microscopes (TEMs) provided the necessary geometric detection efficiency, hence sensitivity and higher spatial resolution, and the reasonably good energy resolution of these detectors permitted reliable separation of overlapping peaks, such as the Kα peak of the biologically important messenger, calcium, and the Kβ peak of another, biologically much more abundant element, potassium. Improvements in the pole-piece design of TEMs to allow closer access of the X-ray detector to the specimen and interfacing the software of one company with detectors provided by another also helped progress, and EPMA, in conjunction with rapid freezing of cells, was ready to address important biological problems, such as the dynamics of the composition of intracellular organelles in situ.
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Zreiba, Nuri A. y Thomas F. Kelly. "Absorption corrections for AEM Analysis of thin-film and sphere samples with large-solid-angle x-ray detectors". Proceedings, annual meeting, Electron Microscopy Society of America 47 (6 de agosto de 1989): 206–7. http://dx.doi.org/10.1017/s0424820100153002.
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Recent advances in x-ray detectors for TEM and STEM instruments have resulted in large increases in the solid angle that these detectors subtend with respect to the sample. These solid angles of order 0.2 steradian mean that x rays emitted into a cone of semi-angle equal to 15° will be intercepted by the detector. Since the conventional absorption correction for x-ray analysis assumes that all detected rays are parallel, we chose to examine whether divergent x rays could change the absorption and fluorescence corrections significantly and should therefore be taken into account.This paper will focus on the effects of such changes on the absorption correction of thin specimens. Two specimen geometries will be considered, namely the usual plane parallel slab and the sphere geometry. Sphere geometries are of interest because they are currently used in the evaluation of the efficiency of x-ray detectors, the results of which are to be presented in the X-ray Optics and Microanalysis Conference in Poland this summer.
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Heald, Steve M. "Strategies and limitations for fluorescence detection of XAFS at high flux beamlines". Journal of Synchrotron Radiation 22, n.º 2 (17 de febrero de 2015): 436–45. http://dx.doi.org/10.1107/s1600577515001320.
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The issue of detecting the XAFS signal from dilute samples is discussed in detail with the aim of making best use of high flux beamlines that provide up to 1013 photons s−1. Various detection methods are compared, including filters with slits, solid state detectors, crystal analyzers and combinations of these. These comparisons rely on simulations that use experimentally determined parameters. It is found that inelastic scattering places a fundamental limit on detection, and that it is important to take proper account of the polarization dependence of the signals. The combination of a filter–slit system with a solid state detector is a promising approach. With an optimized system good performance can be obtained even if the total count rate is limited to 107 Hz. Detection schemes with better energy resolution can help at the largest dilutions if their collection efficiency and count rate limits can be improved.
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FUTATSUGAWA, S., J. ITOH, Y. SAITOH, K. DOI, S. GOTO, S. HATAKEYAMA y K. SERA. "ANNUAL CHANGE OF THE CONCENTRATION OF ELEMENTS IN ENVIRONMENTAL SAMPLES SURROUNDING RADIOISOTOPE WASTE TREATMENT LABORATORY". International Journal of PIXE 15, n.º 03n04 (enero de 2005): 277–84. http://dx.doi.org/10.1142/s0129083505000623.
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Environmental samples (rice, soil, river soil and water, running water, pine needle, milk and grass) are collected from the area surrounding Kaya Memorial Takizawa Laboratory (radioisotope waste management laboratory) neighboring Nishina Memorial Cyclotron Center for detection of radionuclides in them. Rice, which is the most important diet for Japanese, was prepared using a nitric acid ashing and analyzed using ordinary vacuum PIXE for detection of the elemental concentration. Comparison of potassium-40 between the detected value using Ge radiation detector and the analyzed value using PIXE was carried out for accuracy. We examine the change of elemental concentration in rice samples harvested in the different rice paddies in 2001 and in the same rice paddy during 13-year period. There is little change in those.
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Tawfiq, Nada F. y Jaafar Jaleel. "Radon Concentration in Soil and Radon Exhalation Rate at Al-Dora Refinery and Surrounding Area in Baghdad". Detection 03, n.º 04 (2015): 37–44. http://dx.doi.org/10.4236/detection.2015.34006.
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Kämpfer, Peter, Chiu-Chung Young, Hans-Jürgen Busse, Shi-Yao Lin, P. D. Rekha, A. B. Arun, Wen-Ming Chen, Fo-Ting Shen y Y. H. Wu. "Novosphingobium soli sp. nov., isolated from soil". International Journal of Systematic and Evolutionary Microbiology 61, n.º 2 (1 de febrero de 2011): 259–63. http://dx.doi.org/10.1099/ijs.0.022178-0.
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A yellow-pigmented, Gram-negative, rod-shaped, non-spore-forming bacterium, strain CC-TPE-1T, was isolated from oil-contaminated soil near an oil refinery located in Kaohsiung County, Taiwan. 16S rRNA gene sequence analysis of strain CC-TPE-1T showed highest sequence similarity to Novosphingobium naphthalenivorans TUT562T (98.1 %), N. panipatense SM16T (97.9 %) and N. mathurense SM117T (97.6 %) and lower (<97 %) sequence similarity to all other Novosphingobium species. DNA–DNA hybridizations of strain CC-TPE-1T with N. naphthalenivorans DSM 18518T, N. panipatense SM16T and N. mathurense SM117T showed low relatedness of 30 % (reciprocal 35 %), 29.1 % (reciprocal 30.6 %) and 35 % (reciprocal 23.6 %), respectively. The major respiratory quinone was ubiquinone Q-10, the predominant fatty acid was C18 : 1 ω7c (49.9 %) and three 2-hydroxy fatty acids, C14 : 0 2-OH (8.2 %), C15 : 0 2-OH (2.45 %) and C16 : 0 2-OH (1.05 %), were detected. Polar lipids consisted mainly of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phosphatidyldimethylethanolamine, two sphingoglycolipids, phosphatidylmonomethylethanolamine and several unidentified lipids, and a yellow pigment was also detected. The polyamine pattern contained the single major compound spermidine. Characterization by 16S rRNA gene sequence analysis, physiological parameters, pigment analysis and polyamine, ubiquinone, polar lipid and fatty acid compositions revealed that strain CC-TPE-1T represents a novel species of the genus Novosphingobium, for which we propose the name Novosphingobium soli sp. nov., with the type strain CC-TPE-1T (=DSM 22821T =CCM 7706T =CCUG 58493T).
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Getzin, Louis W., Craig G. Cogger y Peter R. Bristow. "Simultaneous Gas Chromatographic Determination of Carbofuran, Metalaxyl, and Simazine in Soils". Journal of AOAC INTERNATIONAL 72, n.º 2 (1 de marzo de 1989): 361–64. http://dx.doi.org/10.1093/jaoac/72.2.361.
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Abstract A method for extraction, cleanup, and simultaneous gas chromatographic detection of carbofuran, metalaxyl, and simazine in soils has been developed. Pesticide residues were extracted from soil with acetone containing 10% 0.2M HCl-KCl buffer (pH 2.0), cleaned up with methylene chloride-carbonate buffer (pH 10.7) solvent partitioning and solid-phase extraction on disposable silica gel columns, and quantitated with gas chromatography using a Supelcowax 10 megabore capillary column and a nitrogen-selective detector. Method limits of detection were 0.02 μg/g for the 3 pesticides in surface soils (0-30 cm depths) and 0.02,0.02, and 0.005 μg/g in soils below 30 cm (subsoils) for carbofuran, metalaxyl, and simazine, respectively. Recoveries for carbofuran, metalaxyl, and simazine were 92.6 ± 5.5, 93.6 ± 5.0, and 88.4 ± 6.7%, respectively, when soil samples were spiked with pesticide concentrations ranging from 0.02 to 2.0 μg/g.
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Iguaz, F. J., T. Saleem, E. Fonda, G. Landrot, L. Manzanillas y F. Orsini. "Detection limit of next-generation of multi-element germanium detectors in the context of Environmental science". Journal of Physics: Conference Series 2380, n.º 1 (1 de diciembre de 2022): 012096. http://dx.doi.org/10.1088/1742-6596/2380/1/012096.
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Abstract One of the main challenges in Environmental sciences is the identification and chemical evolution of polluting traces (e.g, cadmium or antimony) in soil, which requires long acquistion times for accurate measurements at synchrotron facilities. In this context, the potential of a new generation multi-element germanium detectors to identify traces at 0.1-1 ppm in a reasonable time has been studied using Allpix Squared framework [1]. This code has been customized to include the three dimensional electric and weighting field maps generated by COMSOL Multiphysics software, and several features to model the sample environment at SOLEIL synchrotron and the signal response of a germanium detector equipped with a Digital Pulse Processor (DPP). The full simulation chain has been validated by experimental data from SAMBA beamline of SOLEIL synchrotron. This work presents a first estimation of the detection limit to cadmium traces in a soil sample for a future multi-element germanium detector, using this simulation chain.
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Small, Jack, Douglas R. Call, Fred J. Brockman, Timothy M. Straub y Darrell P. Chandler. "Direct Detection of 16S rRNA in Soil Extracts by Using Oligonucleotide Microarrays". Applied and Environmental Microbiology 67, n.º 10 (1 de octubre de 2001): 4708–16. http://dx.doi.org/10.1128/aem.67.10.4708-4716.2001.
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ABSTRACT We report on the development and validation of a simple microarray method for the direct detection of intact 16S rRNA from unpurified soil extracts. Total RNAs from Geobacter chapellei andDesulfovibrio desulfuricans were hybridized to an oligonucleotide array consisting of universal and species-specific 16S rRNA probes. PCR-amplified products from Geobacterand Desulfovibrio were easily and specifically detected under a range of hybridization times, temperatures, and buffers. However, reproducible, specific hybridization and detection of intact rRNA could be accomplished only by using a chaperone-detector probe strategy. With this knowledge, assay conditions were developed for rRNA detection using a 2-h hybridization time at room temperature. Hybridization specificity and signal intensity were enhanced using fragmented RNA. Formamide was required in the hybridization buffer in order to achieve species-specific detection of intact rRNA. With the chaperone detection strategy, we were able to specifically hybridize and detect G. chapellei 16S rRNA directly from a total-RNA soil extract, without further purification or removal of soluble soil constituents. The detection sensitivity for G. chapellei 16S rRNA in soil extracts was at least 0.5 μg of total RNA, representing approximately 7.5 × 106 Geobacter cell equivalents of RNA. These results suggest that it is now possible to apply microarray technology to the direct detection of microorganisms in environmental samples, without using PCR.
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Fadel Kadim, Shahad y Heiyam Najy Hady. "Measurement Radon Gas Concentration in Selected Soil Samples of The of Al-Nada District in Najaf". International Journal of Engineering & Technology 7, n.º 4.36 (9 de diciembre de 2018): 678. http://dx.doi.org/10.14419/ijet.v7i4.36.24222.
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In this study fifty (50) of soil samples of AL-Nada district-Najaf Governorate –Iraq have been collected randomly and studied using solid state nuclear track detectors (CR-39) to determined 226Ra through counting the number of radon tracks by using CR-39 plastic nuclear track detector ,a long- term measurement technique has been considered using special tube of mean (2.5cm) diameter .The detector was placed at (5cm) height and irradiated for 90 days. The chemical etching performed by using (NaOH) solution of 6.25 normality at etching temperature (70C°)for etching period of (7 hrs ).Concentration of radon 222Rn has ranged from (171.237±0.0062) Bq/m3 to (31.982±0.0027) Bq/m3with average value (99.222±0.2476) Bq/m3 while the specific activityof radon has been ranged from (0.471±1.794) Bq/kg to (0.090±7.682) Bq/kg with average value (0.277 1.320)Bq/kgThe results were found to be comparable or lower than similar global reporting data. Accordingly, this area of soil can be considered to have normal levels of natural background radiation.
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Malinowska, Aneta, Marian Jaskóła, Andrzej Korman, Adam Szydłowski, Karol Malinowski y Mirosław Kuk. "Charged projectile spectrometry using solid-state nuclear track detector of the PM-355 type". Nukleonika 60, n.º 3 (1 de septiembre de 2015): 591–96. http://dx.doi.org/10.1515/nuka-2015-0100.
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Abstract To use effectively any radiation detector in high-temperature plasma experiments, it must have a lot of benefits and fulfill a number of requirements. The most important are: a high energy resolution, linearity over a wide range of recorded particle energy, high detection efficiency for these particles, a long lifetime and resistance to harsh conditions existing in plasma experiments and so on. Solid-state nuclear track detectors have been used in our laboratory in plasma experiments for many years, but recently we have made an attempt to use these detectors in spectroscopic measurements performed on some plasma facilities. This paper presents a method that we used to elaborate etched track diameters to evaluate the incident projectile energy magnitude. The method is based on the data obtained from a semiautomatic track scanning system that selects tracks according to two parameters, track diameter and its mean gray level.
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Mishra, Ankit. "Smart Agriculture Monitoring & Auto Irrigation System using IoT with ESP8266". International Journal for Research in Applied Science and Engineering Technology 10, n.º 6 (30 de junio de 2022): 2681–85. http://dx.doi.org/10.22214/ijraset.2022.44382.
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Abstract: In this paper, an IoT-based smart agriculture monitoring and automatic irrigation system are proposed by using ESP8266 Node MCU. Multiple sensors like capacitive soil moisture sensors are fixed inside to measure moisture content present in the soil which will help in the auto-detection of water requisition in the soil. DS18B20 waterproof temperature sensor will measure the temperature of the soil. The DHT22 is used as a humidity and temperature sensor to measure the air temperature and humidity. Soil relative humidity, air temperature, soil temperature, and relative humidity of air are also measured. A small OLED Display is used which is 0.96 inches in size. If any unwanted intrusion by animals or humans is detected on the farm, a PIR motion sensor is used to detect their motion activity. A rain detector sensor is used to detect rain status. A 5 Volt buzzer is for the Alert system and a 5-volt power relay is to control the water pump, whenever a low quantity of moisture is detected in the soil. Overall by using these farming systems users get more benefits and good results from their farming.
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Velásquez, Ana Milena, Fernando Mosos y Giovanni Vela. "Proposal to correct for the effect of background and density in the determination of gamma emitters using sodium iodide detectors". Revista Investigaciones y Aplicaciones Nucleares, n.º 5 (28 de octubre de 2021): 14–25. http://dx.doi.org/10.32685/2590-7468/invapnuclear.5.2021.593.
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This study develops a modification to the spectra decomposition method for sodium iodide scintillation equipment, including correcting the natural background counts for the activity concentration calculation. A comparison of the results obtained between two sodium iodide detectors of 2 X 2 in and 3 x 3 in versus a hyper-pure germanium detector of 50 % relative efficiency is performed for soil, sediment, and water samples. It is found that background correction significantly improves activity concentration results in higher energy regions. The concentration values determined by the different spectrometric systems for the samples analyzed do not show significant differences, which supports the results obtained with the proposed calculation method. The uncertainty associated with the measurement and detection limits for the NaI (Tl) detectors is higher than those obtained with the GeHp detector due to the operation of the two technologies and the presence of interferences in the regions of interest. The study carried out in this work establishes an analytical milestone. The methodological model proposed makes it possible to quantify, with reliable results, low concentration levels of NORM materials and even 131I using sodium iodide detectors, among other analytical applications of general interest.
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Payzant, E. A. y H. W. King. "The Detection of Superlattice Lines in Cu-Zn Alloys using a Solid State Detector". Advances in X-ray Analysis 36 (1992): 671–77. http://dx.doi.org/10.1154/s0376030800019339.
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AbstractUsing a high purity germanium solid state detector with sufficiently high energy resolution to discriminate between copper Kα and Kβ radiation, the superlattice reflections of the ordered Cu-Zn β′ brass structure have be detected by the anomalous dispersion effect. By coupling the high purity germanium solid state detector to a multichannel analyser, the superlattice reflections of the β′ brass structure were also detected by energy dispersive x-ray diffraction. Other applications for this combination of high resolution detector, electronic energy discriminator and multichannel analyser are indicated.
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Ebibuloami, Biere, Ogunremi Ayorinde, Aina Oluwagbenga, Emumejaye Kugbere, Olaoye Adeola y Mustapha Olalekan. "Detection Efficiency of a NaI (Tl) Gamma Spectrometry System for Measurement of Low Level Radioactivity". Physics Access 01, n.º 01 (6 de septiembre de 2021): 61–65. http://dx.doi.org/10.47514/phyaccess.2021.1.1.010.
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Qualitative analysis of radionuclides requires the use of reliable gamma-ray detection system. The NaI(Tl) detector has been widely used and still one of the most used detectors today. It is therefore imperative to validate the reliability of the 5x5 cm2 NaI(Tl) gamma spectrometry system used in carrying out gamma-ray analysis of soil samples in the Radiation and Health Laboratory, Federal University of Agriculture Abeokuta, Nigeria. The gamma ray spectrometer is housed in a 5 cm thick cylindrical lead shield. Calibration was executed using standard materials produced under the auspices of the International Atomic Energy Agency (IAEA). Resolution and detection limit (LD) of the detector were determined using full width at half the maximum of the energy peak of 137Cs and background signal level of the reference materials respectively. Counting efficiencies of the detector was calculated using energies of 1460 keV, 1764keV and 2615 keV for 40K, 226Ra and 232Th respectively. Secondary samples, RGMIX1 and RGMIX2 were formulated and counted to calculate activity concentrations using the NaI(Tl) detector. Resolution of the detector was calculated to be 7.8% of 137Cs, which is good for a NaI(Tl) detector. The counting efficiency of the detector is seen to depend on the gamma ray energy. The results from this work shows that the detector system is suitable gamma spectrometry, and will give quality measurements when used for quantitative determination of radionuclides in environmental samples. The efficiency and resolution of the NaI(Tl) detector should also be determined using photon energies obtained from other radioactive sources.
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Kantarelou, Vasiliki, Andriy Velyhan, Przemysław Tchórz, Marcin Rosiński, Giada Petringa, Giuseppe Antonio Pablo Cirrone, Valeriia Istokskaia et al. "A Methodology for the Discrimination of Alpha Particles from Other Ions in Laser-Driven Proton-Boron Reactions Using CR-39 Detectors Coupled in a Thomson Parabola Spectrometer". Laser and Particle Beams 2023 (27 de febrero de 2023): 1–12. http://dx.doi.org/10.1155/2023/3125787.
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Solid-state nuclear track detectors (CR-39 type) are frequently used for the detection of ions accelerated by laser-plasma interaction because they are sensitive to each single particle. To the present day, CR-39 detectors are the main diagnostics in experiments focused on laser-driven proton-boron (p11B) fusion reactions to detect alpha particles, which are the main products of such a nuclear reaction, and to reconstruct their energy distribution. However, the acceleration of multispecies ions in the laser-generated plasma makes this spectroscopic method complex and often does not allow to unambiguously discriminate the alpha particles generated from p11B fusion events from the laser-driven ions. In this experimental work, performed at the PALS laser facility (600 J, 300 ps, laser intensity 1016 W/cm2), CR-39 detectors were used as main detectors for the angular distribution of the produced alpha particles during a p11B fusion dedicated experimental campaign. Additionally, a CR-39 detector was set inside a Thomson Parabola (TP) spectrometer with the aim to calibrate the CR-39 response for low energetic laser-driven ions originating from the plasma in the given experimental conditions. The detected ion energies were ranging from hundreds of keV to a few MeV, and the ion track diameters were measured for etching times up to 9 hours. The goal of the test was the evaluation of the detectors’ ability to discriminate the alpha particles from the aforementioned ions. Within this study, the calibration curves for protons and silicon low energy ions are accomplished, the overlapping of the proton tracks and alpha particles is verified, and a methodology to avoid this problem is realized.
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West, Sheldon D., Jack H. Weston y Edgar W. Day. "Gas Chromatographic Determination Of Residue Levels Of The Herbicides Trifluralin, Benefin, Ethalfluralin, And Isopropalin In Soil With Confirmation By Mass Selective Detection". Journal of AOAC INTERNATIONAL 71, n.º 6 (1 de noviembre de 1988): 1082–85. http://dx.doi.org/10.1093/jaoac/71.6.1082.
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Abstract A method is presented for the simultaneous or individual determination of the dinitroaniline herbicides trifluralin, benefin, ethalfluralin, and isopropalin in soil. The herbicides are extracted with acetonitrile- water (99 + 1), and the extracts are purified with small, disposable Florisil cartridges prior to analysis by gas chromatography using an electron capture detector or a mass selective detector. When electron capture detection is used as the primary detection system, confirmation with selective detection can be obtained using gas chromatography-mass spectrometry with a mass selective detector and a capillary column operated in the split mode. The limit of detection is 0.01 ppm, and recoveries averaged 95-112% for the 4 herbicides in several different soil types fortified at levels of 0.01- 0.33 ppm
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Zhang, Chi, Zhong Zhong, Ying Jun Sun, Yi Jian Feng y Lu Sun. "Potential of Photoionization Detector for Organic Compounds Analysis at a Brownfield Site Investigation". Applied Mechanics and Materials 602-605 (agosto de 2014): 2379–82. http://dx.doi.org/10.4028/www.scientific.net/amm.602-605.2379.
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Photoionization detector (PID) provided an efficient and inexpensive approach for many gas and vapor analytes. Using PID as a real-time diagnostic tool in contaminated site investigation has been addressed in this study in comparison with post-time GC-MS detection. Total pollutant concentrations from selected field soil samples were calculated by addition of each VOCs and SVOCs contaminant concentration detected via an Agilent 6890 GC-MS, while portable photoionization detector (PPID) values were recorded in real-time during site investigation. Contamination distributions were plotted based on PPID readings and GC-MS data respectively. The results showed a positive correlation between PPID readings and contaminants concentrations, suggesting that PPID reading could be used as a qualitative tool to characterize the approximate range of pollutants. The accuracy of PPID reading for VOCs and SVOCs detection at contaminated site investigation could be optimized by calibration and specialized measurement protocols.
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Zaluzec, Nestor J. "Analytical Formulae for Calculation of X-Ray Detector Solid Angles in the Scanning and Scanning/Transmission Analytical Electron Microscope". Microscopy and Microanalysis 20, n.º 4 (22 de mayo de 2014): 1318–26. http://dx.doi.org/10.1017/s1431927614000956.
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AbstractClosed form analytical equations used to calculate the collection solid angle of six common geometries of solid-state X-ray detectors in scanning and scanning/transmission analytical electron microscopy are presented. Using these formulae one can make realistic comparisons of the merits of the different detector geometries in modern electron column instruments. This work updates earlier formulations and adds new detector configurations.
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Tsiledakis, Georgios, Alain Delbart, Daniel Desforge, Ioanis Giomataris, Thomas Papaevangelou, Richard Hall-Wilton, Carina Höglund et al. "Large High-Efficiency Thermal Neutron Detectors Based on the Micromegas Technology". Universe 4, n.º 12 (28 de noviembre de 2018): 134. http://dx.doi.org/10.3390/universe4120134.
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Due to the so-called 3He shortage crisis, many detection techniques for thermal neutrons are currently based on alternative converters. There are several possible ways of increasing the detection efficiency for thermal neutrons using the solid neutron-to-charge converters 10B or 10B4C. Here, we present an investigation of the Micromegas technology. The micro-pattern gaseous detector Micromegas was developed in the past years at Saclay and is now used in a wide variety of neutron experiments due to its combination of high accuracy, high rate capability, excellent timing properties, and robustness. A large high-efficiency Micromegas-based neutron detector is proposed for thermal neutron detection, containing several layers of 10B4C coatings that are mounted inside the gas volume. The principle and the fabrication of a single detector unit prototype with overall dimension of ~15 × 15 cm2 and its possibility to modify the number of 10B4C neutron converter layers are described. We also report results from measurements that are verified by simulations, demonstrating that typically five 10B4C layers of 1–2 μm thickness would lead to a detection efficiency of 20% for thermal neutrons and a spatial resolution of sub-mm. The high potential of this novel technique is given by the design being easily adapted to large sizes by constructing a mosaic of several such detector units, resulting in a large area coverage and high detection efficiencies. An alternative way of achieving this is to use a multi-layered Micromegas that is equipped with two-side 10B4C-coated gas electron multiplier (GEM)-type meshes, resulting in a robust and large surface detector. Another innovative and very promising concept for cost-effective, high-efficiency, large-scale neutron detectors is by stacking 10B4C-coated microbulk Micromegas. A prototype was designed and built, and the tests so far look very encouraging.
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Seitz, Bjoern, David Bennett y Frank Thomson. "Pulse shape discrimination of CLYC, CLLBC and EJ-276 with SiPM readout". EPJ Web of Conferences 288 (2023): 06010. http://dx.doi.org/10.1051/epjconf/202328806010.
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Solid state detectors for the detection of thermal and fast neutrons find widespread applications. They often operate in a high gamma-radiation field or are required to discriminate between gamma-radiation and neutrons. Organic and in-organic scintillation materials are proposed as detector materials. These materials often exhibit different pulse shapes in their light output, which allows a variety of pulse shape analysis (PSA) techniques to be used to distinguish the two species of radiation. The current maturity of silicon based single photon counters (SiPM) provides a viable visible photon detector alternative to conventional vacuum based photo multiplier tubes (PMT). However, their impact on PSA has not been deeply studied. Three solid state scintillation materials, CLYC, CLLBC and EJ-276 are coupled to an array of SiPM and exposed to neutron and gamma radiation. Their response is characterized using a variety of PSA algorithms and quantified in a Figure of Merit. Conventional charge comparison algorithms perform well for all materials, while a Fourier component analysis shows particular strength for the in-organic materials tested.
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Yocum, J., D. Mayer, J. L. Ouellet y L. Winslow. "Muon track reconstruction in a segmented bolometric array using multi-objective optimization". Journal of Instrumentation 17, n.º 07 (1 de julio de 2022): P07004. http://dx.doi.org/10.1088/1748-0221/17/07/p07004.
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Abstract Recent advances in segmented solid-state detector arrays for rare-event searches have allowed the technology to approach the ton-scale in detector mass and the scale of meters in size. Often focused around searches for neutrinoless double-beta decay or direct dark matter detection, such experiments also have the capability to search for exotic particles that leave track-like signatures across their volume. However, the segmented nature of such detector arrays often sets the spatial resolution and makes the problem of reconstructing track-like paths non-trivial. In this paper, we present an algorithm that improves reconstruction of track-like events in segmented detectors using multi-objective optimization — a computational technique that optimizes more than one cost function at a time without specifying a quantitative weighting between them. Such a technique allows the reconstruction of tracks through a detector and the determination of path-lengths through individual elements. When combined with the reconstructed energy depositions in each element this allows for a calculation of the stopping power of track-like particles and opens the door to searches for particles with abnormal stopping power like monopoles or lightly-ionizing particles (LIPs). Results are presented which evaluate the precision of the reconstruction tools as they currently stand against Monte Carlo generated data. The algorithm is presented in the context of the CUORE experiment, but has applications to other segmented calorimeter detectors.
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Calinawan, Amstrong, Concepcion S. Mendoza y Leonila Adarna. "Preliminary Study on Deltamethrin Residues in Cabbage, Soil and Water from Dalaguete, Cebu, Philippines". KIMIKA 27, n.º 1 (25 de mayo de 2016): 1–11. http://dx.doi.org/10.26534/kimika.v27i1.1-11.
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Pesticides pose a threat to the environment and eventually human health. Extent of contamination of pesticides can be determined and monitored by analysis of pesticide residue in surface water, sediments, soil, and biota. Samples were collected from Manlapay, Barangay Mantalongon in Dalaguete, reportedly the vegetable basket of Cebu, from October to November 2013. Concentration of the pesticide deltamethrin was determined by Gas Chromatography-Electron Capture Detector along with organic matter content (OM), potassium (K) and cation exchange capacity (CEC) using standard methods of analysis. Data showed that deltamethrin was found to be present in soil and cabbage and beyond detection limit in water. Inverse relationship was found between residue in cabbage and in soil confirming pesticide leaching as supported by rainfall data. Organic matter and cation exchange capacity in soil showed significant correlation to detected deltamethrin residue confirming that pyrethroids are strongly bound to organic matter and free exchangeable potassium ions. Deltamethrin residue in water does not show any correlation to any other parameters as it is beyond detection limit, probably due to volatilization and photodegradation of deltamethrin in water. Temperature variation does not show significant difference to deltamethrin residue in all three matrices. The detected deltamethrin residue concentrations in the cabbage (<0.001-0.029 ppm), soil samples (0.007-0.008 ppm) and water samples (<0.0005 ppm) were all below international guideline limits (ASEAN maximum level of 0.5 ppm deltamethrin in cabbage, EC ecologically accepted concentration of 1290 mg deltamethrin/kg soil, and a maximum limit of 0.0025 ppm deltamethrin according to Canadian water quality, respectively). Inspite of the low concentrations detected in cabbage, soil and water samples, an extensive pesticide monitoring on environmental samples within the area is advisable. This will help the adoption of an efficient risk assessment strategy to inform appropriate interventions.
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Chatzakis, John, Iraklis Rigakis, Syed Hassan, Eugene Laurence Clark, Paul Lee y Michael Tatarakis. "Design of a Pixelated Imaging System for Fast Neutron Sources". Designs 3, n.º 2 (23 de mayo de 2019): 25. http://dx.doi.org/10.3390/designs3020025.
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Imaging detectors that use X-ray radiation and pulsed neutron sources have increased in sophistication in recent years due to the use of solid-state detectors. A key method for neutron detection is the nuclear activation of materials by neutrons. Neutron activation can generate radionuclides whose decay produces secondary particle emission that can be detected without interference from the X-rays and other prompt radiation sources and offers advantages over neutrons detection using scintillators. In this paper, we present the design of an imaging system for fast neutron sources. The imaging system utilizes a microcontroller network that communicates using a modified SPI protocol. This network communicates with an interface unit and passes an image to a personal computer. A computer program has been developed to reconstruct the image.
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Dixon, Nile E. J., Stephen D. Monk, James Graham y David Cheneler. "Laminated Flow-Cell Detector with Granulated Scintillator for the Detection of Tritiated Water". Radiation 3, n.º 4 (3 de noviembre de 2023): 211–25. http://dx.doi.org/10.3390/radiation3040017.
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Nuclear sites require regular measurements of the air, soil, and groundwater to ensure the safety of the surrounding environment from potentially hazardous levels of contamination. Although high-energy beta and gamma emitters can often be detected instantly using fixed dosimeters, the detection of low-energy beta emitters is a difficult challenge, especially in groundwater, as its radiation is easily self-absorbed by the surrounding medium. Therefore, it is common practice to sample groundwater and transfer it to a laboratory for analysis using Liquid Scintillation Counting. This work demonstrates a new detector design for the real-time monitoring of tritiated water, a weak beta emitter. This design utilizes a flow cell filled with a granulated scintillator to maximize the surface area of the sample. The cavity is made from plastic sheets, which allow rapid manufacture using readily available lamination sheets. A column of SiPMs in coincidence counting mode has been implemented to reduce noise and allow future extensions to the flow cell for greater detection rates while allowing the detector to fit within limited spaces such as groundwater monitoring boreholes. Using multiple concentrations of tritiated water, this detector has been validated and calibrated, obtaining a minimum detection activity of 26.356 ± 0.889 Bq/mL for a 1-day counting period.
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Heurs, M. "Gravitational wave detection using laser interferometry beyond the standard quantum limit". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, n.º 2120 (16 de abril de 2018): 20170289. http://dx.doi.org/10.1098/rsta.2017.0289.
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Interferometric gravitational wave detectors (such as advanced LIGO) employ high-power solid-state lasers to maximize their detection sensitivity and hence their reach into the universe. These sophisticated light sources are ultra-stabilized with regard to output power, emission frequency and beam geometry; this is crucial to obtain low detector noise. However, even when all laser noise is reduced as far as technically possible, unavoidable quantum noise of the laser still remains. This is a consequence of the Heisenberg Uncertainty Principle, the basis of quantum mechanics: in this case, it is fundamentally impossible to simultaneously reduce both the phase noise and the amplitude noise of a laser to arbitrarily low levels. This fact manifests in the detector noise budget as two distinct noise sources—photon shot noise and quantum radiation pressure noise—which together form a lower boundary for current-day gravitational wave detector sensitivities, the standard quantum limit of interferometry. To overcome this limit, various techniques are being proposed, among them different uses of non-classical light and alternative interferometer topologies. This article explains how quantum noise enters and manifests in an interferometric gravitational wave detector, and gives an overview of some of the schemes proposed to overcome this seemingly fundamental limitation, all aimed at the goal of higher gravitational wave event detection rates. This article is part of a discussion meeting issue ‘The promises of gravitational-wave astronomy’.