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1
Polkowska, Adelajda, Małgorzata Warmuzek, Julia Kalarus, Wojciech Polkowski, and Natalia Sobczak. "A comparison of various imaging modes in scanning electron microscopy during evaluation of selected Si/refractory sessile drop couples after wettability tests at ultra-high temperature." Prace Instytutu Odlewnictwa (Transactions of Foundry Research Institute) 57, no. 4 (2017): 337–44. https://doi.org/10.7356/iod.2017.35.
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In this work, FEI SciosTM field emission gun scanning electron microscope (FEG SEM) equipped with a unique combination of analytical and imaging detectors was utilized to examine structure and chemistry of selected Si/refractory couples. The couples were obtained in wettability tests performed by the sessile drop method coupled with contact heating of a refractory substrate (h-BN, SiC) at ultra-high temperature (up to 1750°C). The SEM observations were carried out on top-views of the couples, in order to evaluate surface and interfacial phenomena in Si/h-BN and Si/SiC systems. A full range of available detectors (e.g. classical Everhart-Thornley detector (ETD) or advanced in-lens detectors) working under various operation modes (secondary electrons (SE), backscattered electrons (BSE), a mixed mode), were used upon analyses in order to reveal specific features of obtained structures.
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Mikmeková, Šárka, Haruo Nakamichi, and Masayasu Nagoshi. "Contrast of positively charged oxide precipitate in out-lens, in-lens and in-column SE image." Microscopy 67, no. 1 (2017): 11–17. http://dx.doi.org/10.1093/jmicro/dfx117.
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Abstract Modern scanning electron microscopes are usually equipped with multiple detectors and enable simultaneous collection of two or even three secondary electron images. The secondary electrons become divided between the detectors in dependence on their initial kinetic energy and emission angle. In this study, sharing of the secondary electrons by out-lens, in-lens and in-column detectors has been systematically investigated. Energy filtering of the signal electrons is demonstrated by separation of the voltage and the topographical contrast in the micrographs obtained by out-lens and in-lens/in-column detectors. The presence of two detectors inside the electron column enables further filtering of the low kinetic energy secondary electrons, which results to unusual contrasts and phenomena. In this paper, inversion of the contrast sign between a positively charged oxide particle and conductive steel matrix (i.e. voltage contrast) in SE images collected under specific imaging conditions is demonstrated.
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Agemura, Toshihide, and Takashi Sekiguchi. "Collection efficiency and acceptance maps of electron detectors for understanding signal detection on modern scanning electron microscopy." Microscopy 67, no. 1 (2018): 18–29. http://dx.doi.org/10.1093/jmicro/dfx124.
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Abstract Collection efficiency and acceptance maps of typical detectors in modern scanning electron microscopes (SEMs) were investigated. Secondary and backscattered electron trajectories from a specimen to through-the-lens and under-the-lens detectors placed on an electron optical axis and an Everhart–Thornley detector mounted on a specimen chamber were simulated three-dimensionally. The acceptance maps were drawn as the relationship between the energy and angle of collected electrons under different working distances. The collection efficiency considering the detector sensitivity was also estimated for the various working distances. These data indicated that the acceptance maps and collection efficiency are keys to understand the detection mechanism and image contrast for each detector in the modern SEMs. Furthermore, the working distance is the dominant parameter because electron trajectories are drastically changed with the working distance.
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Tanrikulu, M. Yusuf. "Pixel level vacuum packaging for single layer microbolometer detectors with on pixel lens." Journal of Electrical Engineering 73, no. 3 (2022): 203–8. http://dx.doi.org/10.2478/jee-2022-0027.
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Abstract This paper presents a new approach for fabrication of single layer microbolometer detectors featuring pixel level vacuum packaging together with a lens on the pixel. The proposed lens structure can be used to increase the fill factor of the detector so that the pixel size can be decreased without decreasing the minimum feature size in the detector which is a problem in single layer microbolometers. The designs of the lens and the fabrication process of pixel level vacuum packaged microbolometer detector together with this lens are given in the framework of this study. The optical and mechanical simulations of the structure are performed. The radius of curvature of the lens is optimized to be 25 μm and it is shown that the condensing efficiency is 100% for 3 μm lens-detector distance. The deflection in the lens structure is found approximately as 0.8 nm in 1 atm environment pressure, showing that the proposed structure is durable. The proposed structure increases the fill factor to twice of the original value without decreasing the minimum feature size in the fabrication processes, resulting in the same amount of improvement in the performance of the detector. This approach can also be used to increase the yield and decrease the fabrication cost of single layer and also standard microbolometers with small pixel sizes, as it integrates the vacuum packaging in the fabrication steps.
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Zhang, Xinming, Xi Cen, Rijuta Ravichandran, Lauren A. Hughes, and Klaus van Benthem. "Simultaneous Scanning Electron Microscope Imaging of Topographical and Chemical Contrast Using In-Lens, In-Column, and Everhart–Thornley Detector Systems." Microscopy and Microanalysis 22, no. 3 (2016): 565–75. http://dx.doi.org/10.1017/s1431927616000751.
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AbstractThe scanning electron microscope provides a platform for subnanometer resolution characterization of material morphology with excellent topographic and chemical contrast dependent on the used detectors. For imaging applications, the predominantly utilized signals are secondary electrons (SEs) and backscattered electrons (BSEs) that are emitted from the sample surface. Recent advances in detector technology beyond the traditional Everhart–Thornley geometry have enabled the simultaneous acquisition and discrimination of SE and BSE signals. This study demonstrates the imaging capabilities of a recently introduced new detector system that consists of the combination of two in-lens (I-L) detectors and one in-column (I-C) detector. Coupled with biasing the sample stage to reduce electron–specimen interaction volumes, this trinity of detector geometry allows simultaneous acquisition of signals to distinguish chemical contrast from topographical changes of the sample, including the identification of surface contamination. The I-C detector provides 4× improved topography, whereas the I-L detector closest to the sample offers excellent simultaneous chemical contrast imaging while not limiting the minimization of working distance to obtain optimal lateral resolution. Imaging capabilities and contrast mechanisms for all three detectors are discussed quantitatively in direct comparison to each other and the conventional Everhart–Thornley detector.
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Minin, Oleg V., Jaime Calvo-Gallego, Yahya M. Meziani, and Igor V. Minin. "Improvement of an InfraRed Pyroelectric Detector Performances in THz Range Using the Terajet Effect." Applied Sciences 11, no. 15 (2021): 7011. http://dx.doi.org/10.3390/app11157011.
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An infrared (IR) pyroelectric detector was investigated for terahertz (THz) detection using the principle of the terajet effect, which focuses the beam beyond the diffraction limit. The terahertz beam was coupled to the detector’s optical window through a two-wavelength-dimension dielectric cubic particle-lens based on the terajet effect. We experimentally demonstrate an enhancement of about 6 dB in the sensitivity under excitation of 0.2 THz without degradation of the noise equivalent power value. The results show that the proposed method could be applied to increase the sensitivity of various commercial IR sensors for THz applications that do not require modification of the internal structure, and it may apply also to acoustics and plasmonic detectors.
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Aslan, Serhat Hasan, and Sinan Kaan Yerli. "Thin lens narcissus model in infrared lens design with cooled detectors." Applied Optics 61, no. 3 (2022): 728. http://dx.doi.org/10.1364/ao.447422.
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Ning, Yan, Shuo Zhang, Yao Hu, Qun Hao, and Xin Tang. "Simulation of Monolithically Integrated Meta-Lens with Colloidal Quantum Dot Infrared Detectors for Enhanced Absorption." Coatings 10, no. 12 (2020): 1218. http://dx.doi.org/10.3390/coatings10121218.
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Colloidal quantum dots (CQDs) have been intensively investigated over the past decades in various fields for both light detection and emission applications due to their advantages like low cost, large-scale production, and tunable spectral absorption. However, current infrared CQD detectors still suffer from one common problem, which is the low absorption rate limited by CQD film thickness. Here, we report a simulation study of CQD infrared detectors with monolithically integrated meta-lenses as light concentrators. The design of the meta-lens for 4 μm infrared was investigated and simulation results show that light intensity in the focused region is ~20 times higher. Full device stacks were also simulated, and results show that, with a meta-lens, high absorption of 80% can be achieved even when the electric area of the CQD detectors was decreased by a factor of 64. With higher absorption and a smaller detector area, the employment of meta-lenses as optical concentrators could possibly improve the detectivity by a factor of 32. Therefore, we believe that integration of CQD infrared detectors with meta-lenses could serve as a promising route towards high performance infrared optoelectronics.
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Erlandsen, Stanley L., Ya Chen, and Chris Frethem. "High Resolution Backscatter Electron (BSE) Imaging using the Autrata Modified YAG BSE Detector: Comparison of an In-lens Hitachi S-900 FESEM with the Below-the-Lens Hitachi S-4700 FESEM." Microscopy and Microanalysis 7, S2 (2001): 1046–47. http://dx.doi.org/10.1017/s1431927600031305.
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To obtain high resolution backscatter electron (BSE) images in field emission SEM (FESEM), one must consider selection of accelerating voltage, beam current, working distance between the specimen and the backscatter detector (in-lens or below-the-lens position for the specimen), the type of BSE detector, and the type of metal used to coat the specimen to improve conductivity and signal collection [1]. A new generation of below-the-lens FESEM have been tested for BSE imaging on biological samples, but no information exists on whether or not high resolution imaging is possible. Here we report the comparison of detection of a colloidal gold standard (6, 12, 18 nm) by high resolution BSE imaging using Autrata-modified YAG detectors in an in-lens FESEM and in a below-the-lens FESEM.Standards were prepared by mixing colloidal gold particles of 6 nm, 12 nm, and 18 nm. The gold particles were attached via poly-l-lysine to glass chips and coated with <1 nm Pt by ion beam sputtering.
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Veneklasen, Lee H. "An electron optical tool kit for transmission and surface electron microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 414–15. http://dx.doi.org/10.1017/s0424820100086374.
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This speculative discussion is offered in memory of Prof. Ben Siegel's fascination with the science of microscope instrumentation. It views the microscope configuration as a set of tools for creating observational opportunities. The central element is a condensor/objective lens in which the specimen is immersed, and along whose axis lie conjugate image and diffraction planes. An illumination system sets up beam conditions, in mode l1, forming a parallel beam, and Mode l2 forming a probe at the center of the lens. A projection system determines the plane within the objective that is magnified onto a recording detector surface. Projection mode P1, views the plane at the lens center, while projection mode P2 views the back focal or diffraction plane behind the lens. These two lens systems, along with apertures, scan coils, and detectors establish various modes of operation which make up the microscopist “tool kit”.
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Konvalina, Ivo, Filip Mika, Stanislav Krátký, Eliška Materna Mikmeková, and Ilona Müllerová. "In-Lens Band-Pass Filter for Secondary Electrons in Ultrahigh Resolution SEM." Materials 12, no. 14 (2019): 2307. http://dx.doi.org/10.3390/ma12142307.
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Scanning electron microscopes come equipped with different types of detectors for the collection of signal electrons emitted from samples. In-lens detection systems mostly consist of several auxiliary electrodes that help electrons to travel in a direction towards the detector. This paper aims to show that a through-the-lens detector in a commercial electron microscope Magellan 400 FEG can, under specific conditions, work as an energy band-pass filter of secondary electrons that are excited by the primary beam electrons. The band-pass filter properties verify extensive simulations of secondary and backscattered electrons in a precision 3D model of a microscope. A unique test sample demonstrates the effects of the band-pass filter on final image and contrast with chromium and silver stripes on a silicon substrate, manufactured by a combination of e-beam lithography, wet etching, and lift-off technique. The ray tracing of signal electrons in a detector model predicate that the through-the-lens detector works as a band-pass filter of the secondary electrons with an energy window of about 3 eV. By moving the energy window along the secondary electron energy spectrum curve of the analyzed material, we select the energy of the secondary electrons to be detected. Energy filtration brings a change in contrast in the image as well as displaying details that are not otherwise visible.
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Słówko, Witold, and Michał Krysztof. "Secondary Electron Detector with the Unipotential Lens Structure for Variable Pressure/Environmental SEM." Solid State Phenomena 186 (March 2012): 24–27. http://dx.doi.org/10.4028/www.scientific.net/ssp.186.24.
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To extend capabilities of classic instruments toward the VP/E technique, authors designed the vacuum-detector system in the form of a simple attachment, which can be mounted to a classic SEM, without changes in its original structure. The main part of the system is the vacuum and detection head, combining the intermediate chamber and electron detectors of chosen kinds. Authors investigate the SE detector showing the unipotential lens structure to find optimum solution for a wide range of gas pressures from high vacuum to pressures exceeding 10 mbar.
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Mir, Amna, Junsheng Yu, Xiaodong Chen, and Ishtiaq Ahmad. "Numerical study of terahertz circular polarized substrate lens dipole antennas for polarization sensitive detectors." International Journal of Microwave and Wireless Technologies 8, no. 3 (2015): 623–31. http://dx.doi.org/10.1017/s1759078715000380.
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Wide band circular polarized (CP) antennas behind extended hemispherical lenses suitable for polarization sensitive THz detector and wireless communication have been designed and characterized using numerical simulation. Two novel, compact and CP dipole antennas are designed and studied for this purpose. CP property of planar antennas is achieved by geometrical modifications of antennas without any complicated feeding structure. Due to compact dimensions, wideband performance and CP behavior, these designs have applications in circular dichroism (CD) spectroscopy and terahertz detectors. This numerical study deals with polarization diversity with substrate lens, effect of off axis displacement on CP behavior of lens antenna which determines number of pixels for any application, far field patterns variation due to lens's internal reflection, directivity variation attributed to internal reflection and losses. Radiation efficiency variation of antenna by antenna dimensions is also studied carefully to design appropriate lens from application's point of view. Off axis performance of antenna on hemisphere lens is also studied and redesigning of antenna by some geometric modification has been carried out to improve far field patterns.
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Katz, J., D. Turnbull, S. T. Ivancic, A. L. Milder, and D. H. Froula. "Measurement of laser absorption in underdense plasmas using near-field imaging of the incident and transmitted beams." Review of Scientific Instruments 93, no. 12 (2022): 123510. http://dx.doi.org/10.1063/5.0100084.
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Measurements of laser absorption in high-temperature, underdense plasmas produced at the Omega Laser Facility are made using two near-field imaging detectors that diagnose the spatial profile and energy of the port P9 beam before and after it transmits through the plasma. The incident beam is sampled using a partial reflection from a full-aperture, (30 cm-diam) uncoated wedge pickoff located before the target chamber vacuum window and final focus lens assembly. A concave mirror reduces the reflected beam size, allowing it to be recorded directly using a charged-coupled device (CCD) camera. The P9 transmitted beam diagnostic (P9TBD) characterizes the transmitted light by terminating the expanded beam on a semi-transparent diffuser and imaging the illuminated surface using a lens and CCD camera. The P9TBD samples a numerical aperture twice as large as the input beam, allowing the energy of transmitted beams with moderate levels of beam spray to be measured accurately. Calibration shots with no plasma provide a path to infer absorption without absolute photometric calibration of either detector. The cross-calibration between the two detectors was measured to remain stable at ±200 ppm, enabling measurements of total beam absorption below 1% with ±0.07% error.
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Faruqi, A. R., and Sriram Subramaniam. "CCD detectors in high-resolution biological electron microscopy." Quarterly Reviews of Biophysics 33, no. 1 (2000): 1–27. http://dx.doi.org/10.1017/s0033583500003577.
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1. Introduction 11.1 The ‘band gap’ in silicon 22. Principles of CCD detector operation 32.1 Direct detection 32.2 Electron energy conversion into light 42.3 Optical coupling: lens or fibre optics? 62.4 Readout speed and comparison with film 83. Practical considerations for electron microscopic applications 93.1 Sources of noise 93.1.1 Dark current noise 93.1.2 Readout noise 93.1.3 Spurious events due to X-rays or cosmic rays 103.2 Efficiency of detection 113.3 Spatial resolution and modulation transfer function 123.4 Interface to electron microscope 143.5 Electron diffraction applications 154. Prospects for high-resolution imaging with CCD detectors 185. Alternative technologies for electronic detection 235.1 Image plates 235.2 Hybrid pixel detectors 246. References 26During the past decade charge-coupled device (CCD) detectors have increasingly become the preferred choice of medium for recording data in the electron microscope. The CCD detector itself can be likened to a new type of television camera with superior properties, which makes it an ideal detector for recording very low exposure images. The success of CCD detectors for electron microscopy, however, also relies on a number of other factors, which include its fast response, low noise electronics, the ease of interfacing them to the electron microscope, and the improvements in computing that have made possible the storage and processing of large images.CCD detectors have already begun to be routinely used in a number of important biological applications such as tomography of cellular organelles (reviewed by Baumeister, 1999), where the resolution requirements are relatively modest. However, in most high- resolution microscopic applications, especially where the goal of the microscopy is to obtain structural information at near-atomic resolution, photographic film has continued to remain the medium of choice. With the increasing interest and demand for high-throughput structure determination of important macromolecular assemblies, it is clearly important to have tools for electronic data collection that bypass the slow and tedious process of processing images recorded on photographic film.In this review, we present an analysis of the potential of CCD-based detectors to fully replace photographic film for high-resolution electron crystallographic applications.
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Chen, Chong, Yuki Shimizu, Ryo Sato, Hiraku Matsukuma, and Wei Gao. "An Off-Axis Differential Method for Improvement of a Femtosecond Laser Differential Chromatic Confocal Probe." Applied Sciences 10, no. 20 (2020): 7235. http://dx.doi.org/10.3390/app10207235.
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This paper presents an off-axis differential method for the improvement of a femtosecond laser differential chromatic confocal probe having a dual-detector configuration. In the proposed off-axis differential method employing a pair of single-mode fiber detectors, a major modification is made to the conventional differential setup in such a way that the fiber detector in the reference detector is located at the focal plane of a collecting lens but with a certain amount of off-axis detector shift, while the fiber detector in the measurement detector is located on the rear focal plane without the off-axis detector shift; this setup is different from the conventional one where the difference between the two confocal detectors is provided by giving a defocus to one of the fiber detectors. The newly proposed off-axis differential method enables the differential chromatic confocal setup to obtain the normalized chromatic confocal output with a better signal-to-noise ratio and approaches a Z-directional measurement range of approximately 46 μm, as well as a measurement resolution of 20 nm, while simplifying the optical alignments in the differential chromatic confocal setup, as well as the signal processing through eliminating the complicated arithmetic operations in the determination of the peak wavelength. Numerical calculations based on a theoretical equation and experiments are carried out to verify the feasibility of the proposed off-axis differential method for the differential chromatic confocal probe with a mode-locked femtosecond laser source.
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Kusaykin, D., and D. Denisov. "Channel estimation in 5G MIMO-OFDM systems based on multibeam lens antennas." Herald of the Siberian State University of Telecommunications and Informatics, no. 4 (December 18, 2021): 56–68. http://dx.doi.org/10.55648/1998-6920-2021-15-4-56-68.
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MIMO systems based on lens antennas are very promising for 5G networks. Some scientific papers have already been devoted to the problem of channel estimation in MIMO systems based on hemispherical lens antennas. However, Luneburg multipath lens antennas are also a promising type of lens antennas for 5G networks. This paper presents the results of channel estimation features research in 5G MIMO-OFDM systems with Luneburg lens antennas. The research results of six different interpolation methods effectiveness for estimating the channel characteristics based on pilot signals and MIMO detectors (Neumann, conjugate gradients, MMSE) in a 5G cellular communication system of the millimeter range are presented.
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Wells, Oliver C., Françoise K. LeGoues, and Rodney T. Hodgson. "In-Lens Low-Loss Electron Detector for the Upper Specimen Stage in the Scanning Electron Microscope." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (1990): 382–83. http://dx.doi.org/10.1017/s0424820100180665.
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For the best resolution in either the scanning electron microscope (SEM) or the transmission electron microscope (TEM) the sample must be mounted in the high-field region of a condenser-objective lens. Detectors for either the secondary electrons (SE) or the backscattered electrons (BSE) in the SEM must allow for the fact that both of these are strongly deflected by the focusing magnetic field of the lens. Typically the SE are collected above the lens, while the BSE are collected using either diode(s) or scintillator(s) between the polepieces.Low-loss electrons (LLE) are scattered from a solid target with an energy loss of less than a few percent of the incident beam energy. These can be collected from a steeply tilted sample from below the exit polepiece of a condenser-objective lens. A suggestion to use the second half of the lens field as an energy filter was shown to by Munro to be unlikely to work because the chromatic dispersion of this part of the lens field is insufficient.The magnetic field of a condenser-objective lens can provide energy filtering as follows.A flat sample is mounted at typically 25° to 30° from the horizontal at or near the center of the lens. Figure 1 shows the trajectories of the electrons scattered with no loss of energy as calculated by Munro. These electrons are confined within a “containment region” with a well-defined boundary beyond which they cannot go. If a suitable detector is placed just inside the surface of this region then it will collect LLE. The slower BSE are confined within a smaller region and so are not collected.
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Tameda, Yuichiro, Mashu Yamamoto, Takayuki Tomida, et al. "Detection of ultra-high energy cosmic ray air showers by Cosmic Ray Air Fluorescence Fresnel lens Telescope for next generation." EPJ Web of Conferences 210 (2019): 06004. http://dx.doi.org/10.1051/epjconf/201921006004.
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In the future, ultra-high energy cosmic ray (UHECR) observatory will be expanded due to the small flux. Then, cost reduction is useful strategy to realize a huge scale observatory. For this purpose, we are developing a simple structure cosmic ray detector named as Cosmic Ray Air Fluorescence Fresnel-lens Telescope (CRAFFT). We deployed CRAFFT detectors at the Telescope Array site and performed a test observation. We have successfully observed UHECR air showers. We will report the status and the result of the test observation.
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Wang, Shi-Yao, Marian Mankos, and J. M. Cowley. "Configured detectors in STEM holography." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (1992): 982–83. http://dx.doi.org/10.1017/s0424820100129541.
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In Gabor's in-line holography, the transmitted plane wave and the beam diffracted by the specimen form an interference pattern (hologram). In a STEM instrument, when the incident probe is scanning over the specimen, the hologram translates across the illuminated portion of the detector plane. The signal produced by the detector can be represented by integrating the product of the hologram with some detector sensitivity function. It had be pointed out long ago by Veneklasen that scanning the hologram over a fixed detector has in effect performed a reconstruction of the hologram simultaneously, and with some specially designed detector the aberration introduced by the objective lens is correctable. This scheme has been reraised recently and some preliminary work will be reported here.
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Xu, Fei, Jose María Ezquiaga, and Daniel E. Holz. "Please Repeat: Strong Lensing of Gravitational Waves as a Probe of Compact Binary and Galaxy Populations." Astrophysical Journal 929, no. 1 (2022): 9. http://dx.doi.org/10.3847/1538-4357/ac58f8.
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Abstract Strong gravitational lensing of gravitational wave sources offers a novel probe of both the lens galaxy and the binary source population. In particular, the strong lensing event rate and the time-delay distribution of multiply imaged gravitational-wave binary coalescence events can be used to constrain the mass distribution of the lenses as well as the intrinsic properties of the source population. We calculate the strong lensing event rate for a range of second- (2G) and third-generation (3G) detectors, including Advanced LIGO/Virgo, A+, Einstein Telescope (ET), and Cosmic Explorer (CE). For 3G detectors, we find that ∼0.1% of observed events are expected to be strongly lensed. We predict detections of ∼1 lensing pair per year with A+, and ∼50 pairs per year with ET/CE. These rates are highly sensitive to the characteristic galaxy velocity dispersion, σ *, implying that observations of the rates will be a sensitive probe of lens properties. We explore using the time-delay distribution between multiply imaged gravitational-wave sources to constrain properties of the lenses. We find that 3G detectors would constrain σ * to ∼21% after 5 yr. Finally, we show that the presence or absence of strong lensing within the detected population provides useful insights into the source redshift and mass distribution out to redshifts beyond the peak of the star formation rate, which can be used to constrain formation channels and their relation to the star formation rate and delay-time distributions for these systems.
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Schaefer, C., M. Geiger, T. Kuntzer, and J. P. Kneib. "Deep convolutional neural networks as strong gravitational lens detectors." Astronomy & Astrophysics 611 (March 2018): A2. http://dx.doi.org/10.1051/0004-6361/201731201.
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Context. Future large-scale surveys with high-resolution imaging will provide us with approximately 105 new strong galaxy-scale lenses. These strong-lensing systems will be contained in large data amounts, however, which are beyond the capacity of human experts to visually classify in an unbiased way. Aims. We present a new strong gravitational lens finder based on convolutional neural networks (CNNs). The method was applied to the strong-lensing challenge organized by the Bologna Lens Factory. It achieved first and third place, respectively, on the space-based data set and the ground-based data set. The goal was to find a fully automated lens finder for ground-based and space-based surveys that minimizes human inspection. Methods. We compared the results of our CNN architecture and three new variations (“invariant” “views” and “residual”) on the simulated data of the challenge. Each method was trained separately five times on 17 000 simulated images, cross-validated using 3000 images, and then applied to a test set with 100 000 images. We used two different metrics for evaluation, the area under the receiver operating characteristic curve (AUC) score, and the recall with no false positive (Recall0FP). Results. For ground-based data, our best method achieved an AUC score of 0.977 and a Recall0FP of 0.50. For space-based data, our best method achieved an AUC score of 0.940 and a Recall0FP of 0.32. Adding dihedral invariance to the CNN architecture diminished the overall score on space-based data, but achieved a higher no-contamination recall. We found that using committees of five CNNs produced the best recall at zero contamination and consistently scored better AUC than a single CNN. Conclusions. We found that for every variation of our CNN lensfinder, we achieved AUC scores close to 1 within 6%. A deeper network did not outperform simpler CNN models either. This indicates that more complex networks are not needed to model the simulated lenses. To verify this, more realistic lens simulations with more lens-like structures (spiral galaxies or ring galaxies) are needed to compare the performance of deeper and shallower networks.
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Starasotnikau, M. A., I. V. Padskrebkin, and R. V. Feodortsau. "Method for Determining Elements of Internal Orientation Calibration in Multi-Matrix Optoelectronic Devices." Science & Technique 19, no. 5 (2020): 428–36. http://dx.doi.org/10.21122/2227-1031-2020-19-5-428-436.
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In the operation schemes of optical electronic devices (OED), such as digital autocollimators, direction finders, Shack-Hartmann sensors, as well as astro-orientation systems, projection measuring systems, geometric calibration schemes for OED, the photo-detector acts not only as a receiving device, but also as a measuring device. The tasks facing the OED photo-detectors. The solution to the problem is the use of several photo-detectors installed on one electronic board. Since OED photo-detectors act, inter alia, as measuring devices, it is necessary to perform their geometric calibration. Geometric calibration involves the measurement of interior orientation parameters used in the processing of OED images. Geometric calibration makes it possible to eliminate errors in mutual exposure of photo-detectors on one electronic board installed in the focal plane, as well as distortions introduced by the OED lens, primarily by distortion. The correctness of the interior orientation parameter determination is influenced by the relative position of the collimator, with the help of which the geometric calibration is performed, and the calibrated OED itself, i. e. the external orientation elements. The task is to separate the interior orientation parameters and the elements of external orientation. This is achieved using the method of mathematical processing of measured data in the forward and inverted positions of the collimator. This method of geometric calibration allows to use it for geometric calibration of OED with a large number of photo-detectors. The paper presents the results of the geometric calibration of the interior orientation parameters when the collimator projects a test object onto three photo-detectors of the OED layout. The factors influencing on the accuracy of the geometric calibration of the interior orientation elements for OED are determined in the paper. The developed method for geometric calibration of the interior orientation parameters for multi-matrix OED provides high measurement accuracy – not more than 0.1''–0.2''.
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Dellepiane, G., P. Casolaro, P. D. Häffner, et al. "Instruments and methods for theranostic radioisotope production at the Bern medical cyclotron." Journal of Physics: Conference Series 2374, no. 1 (2022): 012179. http://dx.doi.org/10.1088/1742-6596/2374/1/012179.
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Radioisotopes for theranostics are essential for nuclear medicine developments. Their production using solid target stations is challenging and new instruments and methods derived from particle physics are needed. A research program is ongoing at the 18 MeV Bern medical cyclotron, equipped with a solid target station and a 6 m long beam transfer line ending in a separate bunker. To irradiate 6 mm diameter compressed powder pellets, novel target “coins” were conceived and realized together with methods to assess the beam energy and the production cross sections. To measure the activity at End of Beam (EoB) a system based on a CdZnTe detector was installed. To accurately assess the properties of the beam, novel non-destructive one- and two-dimensional beam monitoring detectors were developed. An ultra-compact active irradiation system based on a novel magnetic lens and two-dimensional beam detectors was conceived and tested with the beamline and recently installed in an outport of the cyclotron.
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He, X. "Ring Imaging Cherenkov Detector Technologies for Particle Identification in the Electron-Ion Collider Experiments." International Journal of Modern Physics: Conference Series 46 (January 2018): 1860080. http://dx.doi.org/10.1142/s2010194518600807.
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In the proposed Electron-Ion Collider (EIC) experiments, particle identification (PID) of the final state hadrons in the semi-inclusive deep inelastic scattering allows the measurement of flavor-dependent gluon and quark distributions inside nucleons and nuclei. The EIC PID consortium (eRD14 Collaboration) has been formed for identifying and developing PID detectors using Ring Imaging Cherenkov (RICH) techniques for the EIC experiments. A modular Ring Imaging Cherenkov (mRICH) detector has been designed for particle identification in the momentum coverage from 3 GeV/c to 10 GeV/c. The mRICH detector consists of an aerogel radiator block, a Fresnel lens, a mirror-wall and a photosensor plane. The first prototype of this detector was successfully tested at Fermi National Accelerator Laboratory in April 2016 for verifying the detector working principles. This talk will highlight the mRICH beam test results and their comparison with GEANT4-based detector simulations. An implementation of the mRICH detector concept in the Forward Angle sPHENIX spectrometer at BNL will also be mentioned in this talk.
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Gauvin, Raynald, and Pierre Hovington. "On the Contrast of Precipitates Observed with a FE-SEM." Microscopy and Microanalysis 5, S2 (1999): 316–17. http://dx.doi.org/10.1017/s1431927600014902.
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It has been shown recently that precipitates as small as 10 nm can be imaged with a FE-SEM using a Through-The-Lens (TTL) SE detector or the so-called Upper Detector (UD). This is a very significant finding because normally, such small precipitates are observed in the TEM where specimen preparation techniques are generally a timely process. However, from Monte Carlo simulations using CASINO, it has been shown that NbC precipitates embedded in Fe as small than 6 nm can be imaged with BE. The experimental demonstration was difficult because no good BSE detectors were available at that time for low energy work.Recently, a new BSE detector has been developed for low energy work from the GW corporation, the Centaurus BSE detector. This detector is coupled with an HITACHI S-4700 FESEM In this work, images of Mg2Zn precipitates in Al obtained with the UD and the Centaurus BSE detector are compared.
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Ferrier, R. P., and S. McVitie. "A new method for the observation of Type II magnetic contrast." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (1990): 764–65. http://dx.doi.org/10.1017/s0424820100176952.
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Type II magnetic contrast was first observed by Philibert and Tixier and relies on the change in the effective backscattering coefficient due to interaction of the scattered electrons within the specimen and the local magnetic induction (for a review see Tsuno). Depending on the tilt of the specimen and the position of the backscattered electron detector(s), contrast due to the presence of either or both domains and domain walls can be obtained; in the case of the latter, the standard geometry is for the specimen to be normal to the incident beam and the detectors are positioned above it and close to the optic axis. This is the geometry adopted in our studies, which used a JEOL 2000FX with a special split objective lens polepiece; this permitted the specimen to be in magnetic field-free space, the separate lens gaps above and below allowing good probe forming capabilities combined with excellent Lorentz imaging performance. A schematic diagram is shown in Fig. 1.
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Jones, A. V. "New imaging modes in STEM." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 648–49. http://dx.doi.org/10.1017/s0424820100105308.
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The most often quoted advantage of STEM over conventional TEM is the ability to produce multiple simultaneous images by the use of multiple detector systems. In practice, this postulated advantage has seldom been fully utilised, mainly because of the practical difficulties in designing such detector systems.Most STEMs to date have been constructed as two-channel instruments combining annular dark-field imaging with either filtered bright-freld or inelastic imaging. More complex forms of bright-field detector have been employed1, as have parallel-readout systems for energy-loss spectra but the ability of the spectrometer to produce multiple simultaneous images has not been fully utilised.The basis of the problem lies in the fact that the objective lens and the detector system(s) have in most cases been designed by the manufacturers as separate entities in order to simplify the later addition of user-specific detectors. Since the acceptance angle of even the best spectrometers is relatively small, additional post-specimen lenses [with their attendant aberrations] had to be added in order to make full use of the spectrometer.
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Yoshino, Masao, Seiichi Yamamoto, Kohei Nakanishi, et al. "Development and performance evaluation of a thin GAGG:Ce scintillator plate for high resolution synchrotron radiation X-ray imaging." Journal of Instrumentation 19, no. 10 (2024): P10030. http://dx.doi.org/10.1088/1748-0221/19/10/p10030.
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Abstract Scintillator-based X-ray imaging detectors are pivotal in numerous scientific and practical domains, including medical imaging, food and device inspection, and security monitoring. Recent advancements have spurred interest in 4D X-ray imaging using synchrotron radiation, necessitating higher temporal resolutions. Consequently, this places stringent demands on X-ray detector technology, especially when X-ray energy exceeds 20 keV. The selection of a suitable scintillator material is crucial for achieving optimal timing resolution, yet it poses a significant challenge in dynamic X-ray imaging. This study delves into the optimization of scintillator properties and their impact on spatial resolution and light output, elucidating the performance of Ce-doped Gd3Ga3Al2O12 (GAGG:Ce) scintillators for X-ray imaging applications. We developed a micro X-ray imaging detector using a 100 μm-thick GAGG:Ce scintillator plate and conducted X-ray imaging tests at the Aichi SR facility. The results demonstrated that the resolution, quantified as the chart slit width at a contrast transfer function (CTF) value of 10%, reached 2 ∼ 3 μm with a 4× lens, 0.52 μm± 0.03 μm with a 20× lens, and 0.42 μm± 0.01 μm with a 40× lens. Although the results of this study did not achieve a spatial resolution nearing the effective pixel size of the 40× lens, the text also elucidates the underlying reasons for this limitation. Furthermore, we compared the X-ray sensitivity of our GAGG:Ce scintillator plate with that of a commercial LuAG:Ce scintillator, revealing an approximately 1.5-fold increase in light output. As a demonstration, transmission images of dried small fish were captured using the GAGG:Ce scintillator plate and the developed X-ray imaging system. These findings highlight the potential of the X-ray imaging detector devised in this study for future generations of X-ray imaging applications.
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Liu, Hai Rui, and Jun Sheng Yu. "Characterization of Metal-Semiconductor Schottky Diodes and Application on THz Detection." Advanced Materials Research 683 (April 2013): 729–32. http://dx.doi.org/10.4028/www.scientific.net/amr.683.729.
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This paper presents a kind of air-bridged GaAs Schottky diodes which offer ultra low parasitic capacitance and series resistance in millimeter and THz wavelength. The Schottky barrier diodes have several advantages when used as millimeter wave and terahertz video, or power detectors. These include their fast time response, room temperature operation, simple structure and low cost. This paper describes the characterization of the metal-semiconductor Schottky diodes including principle, diode structure, non-linear voltage-current characteristic and signal-rectifying performance. For application, a quasi-optical THz detector was made by using the proposed Schottky diodes. It utilized a hyper hemispherical silicon lens to coupleand THz radiation to the diodes by integrating on a broadband planar bow-tie antenna. The measurement results of the Schottky diode based detector show a good room temperature performance.
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Barbi, Nicholas C., and Richard B. Mott. "Take-off Angle Imaging: A New Image Mode for Scanning Electron Microscopy." Microscopy Today 21, no. 3 (2013): 22–25. http://dx.doi.org/10.1017/s1551929513000497.
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Traditional electron detectors for scanning electron microscopes (SEMs) are the Everhart-Thornley detector located on one side of the specimen and the overhead backscattered electron detector (BSED), usually mounted under the final lens. In 2011 PulseTor introduced an efficient BSED based on scintillator/silicon photomultipler technology that is small enough to be mounted on the tip of an X-ray detector. The scintillator converts the electron signal to light, which is in turn converted to an electrical current in the silicon photomultiplier (SiPM). Silicon photomultipliers were initially developed in Russia in the 1990s. The review article by Dolgoshein et al. cites much of the historical development. Following the recent work of Piemonte and others, the SiPM consists of an array of many identical and independent detecting elements (microcells) connected in parallel on a common Si substrate. Each microcell is an avalanche photodiode only tens of micrometers in size.
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Chen, Gang-Chi, Prasad L. Polavarapu, and Stephen Weibel. "New Design for Fourier Transform Infrared Vibrational Circular Dichroism Spectrometers." Applied Spectroscopy 48, no. 10 (1994): 1218–23. http://dx.doi.org/10.1366/0003702944027499.
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Fourier transform infrared (FT-IR) spectrometers are commonly designed with small-area detectors and tight focusing mirrors. Vibrational circular dichroism (VCD) measurements made with such FT-IR instruments contain polarization artifacts, and VCD measurements on both enantiomers (or one enantiomer and racemic mixture) are required in order to reduce these artifacts. This restriction limits the VCD measurements to only those samples for which both enantiomers (or one enantiomer and racemic mixture) are available. Recently a modified design was reported in the literature where the mirrors between sample and detector were replaced with a BaF2 lens, and a larger-area detector was substituted for the smaller-area counterpart. These modifications successfully alleviated some of the artifact problems. This design, however, is not suitable for polarizing interferometers, where polarizations exiting the interferometer are to be preserved to a high degree of purity. In addition, it is not clear whether the throughput enhancement advantage realized with a larger-area detector completely offsets the disadvantage from increased noise with detector area. Furthermore, BaF2 lenses reduce the broad range routinely available on an FT-IR instrument. Here we report a new design that replaces all the mirrors at the exit port of the interferometer with two KBr lenses and retains the full spectral range (4000–400 cm−1) of mid-infrared FT-IR spectrometers. VCD measurements obtained with small- (1 × 1 mm) and large- (4 × 4 mm) area detectors are found to have similar signal quality.
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Van Esch, P., J.-F. Clergeau, and K. Medjoubi. "An electrostatic lens to reduce parallax in gas detectors with cylindrical geometry." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 540, no. 2-3 (2005): 361–67. http://dx.doi.org/10.1016/j.nima.2004.11.035.
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Lee, Kil Sung, Seung Hoon Kim, Han Ki Min, et al. "The Nondestructive Evaluation Method for the Optical Glass Lens by Resonant Ultrasound Spectroscopy." Key Engineering Materials 321-323 (October 2006): 1435–38. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.1435.
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In this research, we proposed nondestructive evaluation method of a flaw in an optical glass lens by resonant ultrasound spectroscopy (RUS). An optical glass lens is used for improving signal coupling between fibers, emitters and detectors. The shape of optical glass lens is an aspherical lens with 3mm in length and 6.35 mm in diameter. For nondestructive evaluation of an aspherical lens, we made of the measuring system by RUS. For flaw evaluation by the RUS to verify the data obtained from the experiment, we carried out simulation by explicit finite elements method, and compared the experimental results with simulation results. Also, we compared the resonant frequencies of specimens with some defect with those of acceptable specimens. The histogram drawn from these data and the available resonance mode surveyed were used to classify the acceptable specimens in the plant.
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Apkarian, RP, T. A. T. Lee, and V. P. Conticello. "Metal Coating Techniques for Contrast Enhancement of Biological Macromolecular Complexes In HRSEM, STEM and TEM Image Modes." Microscopy and Microanalysis 6, S2 (2000): 292–93. http://dx.doi.org/10.1017/s143192760003395x.
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Modern field emission SEMs fitted with in-lens or near-lens (W.D. = l-3mm.) stages and above-lens SE detectors are capable of imaging 1-5 nm features at high voltage (15-30kV) and 5-10 nm features at low voltage (l-5kV). Ultrathin fine-grain refractory metal coatings were shown to optimize higher-solution (HR) secondary electron imaging of light element specimens especially biological samples. Ambient temperature dried specimens and frozen-hydrated cryo-specimens coated with continuous 1nm-thick metal films and staged in-lens have revealed biologically significant features of molecular dimension in tandem HRSEM and scanning transmission (STEM) modes. Although positive and negative stains have proved useful for general contrast enhancement of TEM specimens these stains alter many of our new genetically synthesized block protein copolymers. Therefore we have turned to non-evaporated metal coatings for contrast enhancement of these specimens in the TEM.
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Li, Qingyan, Shuo Wang, Jiajie Wu, Feiyue Chen, Han Gao, and Hai Gong. "Design of Lidar Receiving Optical System with Large FoV and High Concentration of Light to Resist Background Light Interference." Micromachines 15, no. 6 (2024): 712. http://dx.doi.org/10.3390/mi15060712.
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Lidar has the advantages of high accuracy, high resolution, and is not affected by sunlight. It has been widely used in many fields, such as autonomous driving, remote sensing detection, and intelligent robots. However, the current lidar detection system belongs to weak signal detection and generally uses avalanche photoelectric detector units as detectors. Limited by the current technology, the photosensitive surface is small, the receiving field of view is limited, and it is easy to cause false alarms due to background light. This paper proposes a method based on a combination of image-side telecentric lenses, microlens arrays, and interference filters. The small-area element detector achieves the high-concentration reception of echo beams in a large field of view while overcoming the interference of ambient background light. The image-side telecentric lens realizes that the center lines of the echo beams at different angles are parallel to the central axis, and the focus points converge on the same focal plane. The microlens array collimates the converged light beams one by one into parallel light beams. Finally, a high-quality aspherical focusing lens is used to focus the light on the small-area element detector to achieve high-concentration light reception over a large field of view. The system achieves a receiving field of view greater than 40° for a photosensitive surface detector with a diameter of 75 μm and is resistant to background light interference.
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Christinck, J., F. Hirt, H. Hofer, et al. "A germanium-vacancy center in diamond as single-photon source for radiometric application." Journal of Physics: Conference Series 2864, no. 1 (2024): 012009. http://dx.doi.org/10.1088/1742-6596/2864/1/012009.
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Abstract We present the metrological characterization of a single-photon source based on a germanium-vacancy center in diamond under a solid immersion lens in a confocal microscope setup at room temperature. It was characterized in terms of the emission’s spectral distribution, single-photon purity, temporal stability and the emitter’s excited state lifetime and saturation behavior. An Allan deviation analysis was performed on the emission of the single-photon source to determine the optimal averaging time of the photon flux. The single-photon source was used for the relative calibration of the detection efficiency of two single-photon avalanche diode detectors. The results were compared with measurements using attenuated laser light for the calibration of the detectors.
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Konvalina, Ivo, Aleš Paták, Martin Zouhar, et al. "Quantification of STEM Images in High Resolution SEM for Segmented and Pixelated Detectors." Nanomaterials 12, no. 1 (2021): 71. http://dx.doi.org/10.3390/nano12010071.
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The segmented semiconductor detectors for transmitted electrons in ultrahigh resolution scanning electron microscopes allow observing samples in various imaging modes. Typically, two standard modes of objective lens, with and without a magnetic field, differ by their resolution. If the beam deceleration mode is selected, then an electrostatic field around the sample is added. The trajectories of transmitted electrons are influenced by the fields below the sample. The goal of this paper is a quantification of measured images and theoretical study of the capability of the detector to collect signal electrons by its individual segments. Comparison of measured and ray-traced simulated data were difficult in the past. This motivated us to present a new method that enables better comparison of the two datasets at the cost of additional measurements, so-called calibration curves. Furthermore, we also analyze the measurements acquired using 2D pixel array detector (PAD) that provide a more detailed angular profile. We demonstrate that the radial profiles of STEM and/or 2D-PAD data are sensitive to material composition. Moreover, scattering processes are affected by thickness of the sample as well. Hence, comparing the two experimental and simulation data can help to estimate composition or the thickness of the sample.
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Xia, Wenfeng, Daniele Piras, Johan C. G. van Hespen, Wiendelt Steenbergen, and Srirang Manohar. "A new acoustic lens material for large area detectors in photoacoustic breast tomography." Photoacoustics 1, no. 2 (2013): 9–18. http://dx.doi.org/10.1016/j.pacs.2013.05.001.
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Zhang, Labao, Chao Wan, Min Gu, et al. "Dual-lens beam compression for optical coupling in superconducting nanowire single-photon detectors." Science Bulletin 60, no. 16 (2015): 1434–38. http://dx.doi.org/10.1007/s11434-015-0860-6.
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Liao, Kai, Shuxun Tian, and Xuheng Ding. "Probing compact dark matter with gravitational wave fringes detected by the Einstein Telescope." Monthly Notices of the Royal Astronomical Society 495, no. 2 (2020): 2002–6. http://dx.doi.org/10.1093/mnras/staa1388.
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ABSTRACT Unlike the electromagnetic radiation from astrophysical objects, gravitational waves (GWs) from binary star mergers have much longer wavelengths and are coherent. For ground-based GW detectors, when the lens object between the source and the Earth has mass ∼1−105 M⊙, the diffraction effect should be considered since the chirping wavelengths are comparable to the scale of the barrier (its Schwarzschild radius). The waveform will thus be distorted as the fringes. In this work, we show that signals from the third-generation GW detectors like the Einstein Telescope (ET) would be a smoking gun for probing the nature of compact dark matter (CDM) or primordial black holes. Detection of the lensing effects becomes harder when the lens mass is smaller. ET is more sensitive than LIGO, the constraint is available for CDM mass &gt;5 M⊙ while LIGO can only detect the mass &gt;100 M⊙. For a null search of the fringes, one-year observation of ET can constrain the CDM density fraction to ∼10−2 to 10−5 in the mass range MCDM = 10−100 M⊙.
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Brink, H. A., C. Trevor, J. Hunt, and P. E. Mooney. "A New High Performance Detector for Electron Energy Loss Spectroscopy." Microscopy and Microanalysis 6, S2 (2000): 212–13. http://dx.doi.org/10.1017/s1431927600033559.
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The serial detectors traditionally used in Electron Energy Loss Spectroscopy (EELS) have mostly been replaced by parallel detection systems, for reasons of efficiency and ease of use. So far most parallel detection systems have been based on fiber or lens coupled Photo Diode Array (PDA). Although these systems have proven satisfactory they have some limitations: 1) high readout noise, 2) limited correction for gain variations and 3) point spread function or cross talk between channels all of which effects the ultimate sensitivity and resolution. This paper discusses a newly developed parallel detector for EELS based on a CCD and a new type of scintillator and fiber technology. The new detector shows large improvements in all areas of performance.The sensitivity of a detector is limited by the readout noise at low incident electron dose and the gain correction at high dose. Both these areas have been addressed in the new design. The readout noise is equivalent to approximately 1/2 a primary electron, about 40 times better than a typical PDA.
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Apkarian, R. P., and S. Lund. "Imaging Cultured Cells on Protein Coated Silicon Chips Using Low-Voltage in-Lens SEM." Microscopy and Microanalysis 3, S2 (1997): 1229–30. http://dx.doi.org/10.1017/s1431927600013039.
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A Schottky Field Emission (SFE) SEM (Topcon DS-130F) equipped with dual stages and dual secondary electron (SE) detectors operated at high voltage (25 kV) provided useful magnifications of 200 x - 200,000 x and particle resolution in the 5 nm range from chromium (Cr) coated bulk (1 mm3) biological samples. Additionally, high voltage in-lens SFE-SEM, at magnifications > 200,000 x, provided high resolution images with 2-3 nm particle contrasts from Cr coated negatively-stained phospholipid vesicles (100 nm diameter) adhered to uncoated silicon (Si) chips.We recently developed low voltage strategies for quality in-lens imaging of Cr coated cell cultures at low and high magnifications. Due to unfavorable specimen-beam interactions at high voltage, not encountered with ultimately small volume organic specimens on Si chips or large bulk specimens, cells on protein matrix coated Si chips were imaged at low and high magnification in-the-lens of the DS-130F with beam energies of 5 kV.
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Seo, Eungwang, Tjonnie G. F. Li, and Martin A. Hendry. "Inferring Properties of Dark Galactic Halos Using Strongly Lensed Gravitational Waves." Astrophysical Journal 966, no. 1 (2024): 107. http://dx.doi.org/10.3847/1538-4357/ad35bb.
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Abstract Gravitational waves (GWs) can be deflected, similarly to electromagnetic (EM) waves, by massive objects through the phenomenon of gravitational lensing. The importance of GW lensing for GW astronomy is becoming increasingly apparent in the GW detection era, in which nearly 100 events have already been detected. As current ground-based interferometers reach their design sensitivities, it is anticipated that these detectors may observe a few GW signals that are strongly lensed by the dark halos of intervening galaxies or galaxy clusters. Analyzing the strong lensing effects on GW signals is, thus, becoming important to understand the lens’ properties and correctly infer the intrinsic GW source parameters. However, one cannot accurately infer lens parameters for complex lens models with only GW observations because there are strong degeneracies between the parameters of lensed waveforms. In this paper, we discuss how to conduct parameter estimation of strongly lensed GW signals and infer the lens parameters using additional EM information, including the lens galaxy’s axis ratio and the GW source-hosting galaxy’s lensed images. We find that for simple spherically symmetric lens models, the lens parameters can be well recovered using only GW information. On the other hand, recovering the lens parameters requires systems in which four or more GW images are detected with additional EM observations for nonaxially symmetric lens models. Combinations of GW and EM observations can further improve the inference of the lens parameters.
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Cusin, Giulia, Ruth Durrer, and Irina Dvorkin. "Lensing Magnification Seen by Gravitational Wave Detectors." Universe 8, no. 1 (2021): 19. http://dx.doi.org/10.3390/universe8010019.
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In this paper, we studied the gravitational lensing of gravitational wave events. The probability that an observed gravitational wave source has been (de-)amplified by a given amount is a detector-dependent quantity which depends on different ingredients: the lens distribution, the underlying distribution of sources and the detector sensitivity. The main objective of the present work was to introduce a semi-analytic approach to study the distribution of the magnification of a given source population observed with a given detector. The advantage of this approach is that each ingredient can be individually varied and tested. We computed the expected magnification as both a function of redshift and of the observedsource luminosity distance, which is the only quantity one can access via observation in the absence of an electromagnetic counterpart. As a case study, we then focus on the LIGO/Virgo network and on strong lensing (μ>1).
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Karsenty, Avi, Shmuel Feldman, Zvi Veig, and Yoel Arieli. "Full Field Imaging Ellipsometry (FFIE) Platform Using CCD Camera and Advanced Software for Simultaneous Spots' Sensing and Measurement." International Journal of Measurement Technologies and Instrumentation Engineering 6, no. 1 (2017): 33–45. http://dx.doi.org/10.4018/ijmtie.2017010104.
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This article describes a new approach for performing full field imaging ellipsometry. In this new technique, the objective lens of a high numerical aperture microscope is used to illuminate the surface of a 2D object. The light reflected from each point of the surface is gathered by the same lens and projected onto a 2D CCD detectors array; thus, enabling the measurement of numerous surface points simultaneously. Using this simple method, areas of up to 0.9 cm2 can be measured with high accuracy. Since the nanotechnology domain is rapidly growing, such a technique can bring benefits to the scientific community, facing the need to analyze large surfaces of thin films.
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Boudjemaa, Kheddar, and Ping Song. "Indoor Human Detection and Monitoring System Using PIR Wireless Sensors Array." Applied Mechanics and Materials 541-542 (March 2014): 1297–303. http://dx.doi.org/10.4028/www.scientific.net/amm.541-542.1297.
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This paper presents a design and implementation of an efficient and low cost system for indoor monitoring of human intrusion. The system design is based on the use of already available pyroelectric infrared passive sensors (PIR) that are able to detect thermal perturbation caused by moving objects within their field of view (FOV). Our design uses the PIR sensors in the geometric context as binary detectors with adaptive threshold estimation. The combined field of view of three PIR detectors is modulated by a custom designed lens mask to estimate the bearing angle of the single human intrusion. The prototype is formed by a sensing module routed wirelessly to another host module to visualize processed raw data.
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Köseoglu, I. "Design of the barrel and endcap DIRC detectors for particle identification in PANDA." International Journal of Modern Physics A 35, no. 34n35 (2020): 2044020. http://dx.doi.org/10.1142/s0217751x20440200.
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The PANDA experiment at the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt/Germany aims to investigate fundamental questions of hadron physics. PANDA is designed as a fixed-target experiment for an antiproton beam with a momentum range of 1.5 GeV/[Formula: see text] to 15 GeV/[Formula: see text]. In order to obtain an excellent particle identification of pions and kaons, two independent DIRC detectors have been developed for two adjacent spatial regions. The Barrel DIRC covers polar angles from [Formula: see text]–[Formula: see text] and performs [Formula: see text] separation with [Formula: see text] or more for momenta from 0.5 to 3.5 GeV/[Formula: see text]. The novel Endcap Disc DIRC (EDD) detector will cover the forward polar angles between [Formula: see text] and [Formula: see text] and will provide a [Formula: see text] separation from 0.5 GeV/[Formula: see text] up to 4 GeV/[Formula: see text] with a separation power at least [Formula: see text]. The design of the Barrel DIRC is based on the successful BaBar DIRC and the SuperB FDIRC R&D with several improvements to optimize the performance for PANDA. Both PANDA DIRC detectors use synthetic fused silica as material for radiators and light guides and lifetime-enhance Microchannel Plate PMTs (MCP-PMTs) as sensors. The Barrel DIRC uses narrow bars as a radiator, a prism-shaped expansion volume and a complex multi-layer spherical lens as focusing system. The Cherenkov radiator for the EDD is a large, 2 cm thick fused silica plate that is divided into four identical quadrants. A combination of bars and cylindrical elements with aluminum coating focus the Cherenkov light on the MCP-PMTs with segmented anode plates. The technical design of the two DIRC detectors and the performance of prototypes, tested in a mixed hadron beam at CERN, will be discussed.
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Wang, Yanping, Gang Li, Jie Zhang, et al. "Improving the detection efficiency and modulation transfer function of lens-coupled indirect X-ray imaging detectors based on point spread functions simulated according to lens performance parameters." Journal of Synchrotron Radiation 25, no. 4 (2018): 1093–105. http://dx.doi.org/10.1107/s1600577518007889.
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Lens-coupled indirect X-ray imaging detectors have the advantage of high resolution and the disadvantage of low detection efficiency. Using thicker single-crystalline films (SCFs) can improve the detection efficiency. However, the image quality will become worse due to the degradation of the point spread function (PSF) and modulation transfer function (MTF). This disadvantage can be improved by deconvolution with the PSF, which is unknown. In this article, a method was established to acquire the PSF based on a simulation of the imaging process for a lens-coupled indirect X-ray imaging detector. Because the structural parameters of commercial lenses cannot usually be obtained, the PSFs were calculated from lens performance parameters. PSFs were calculated using the conditions of 12 keV X-ray energy, 10× and 40× magnification objectives and 4.6 µm- and 20 µm-thick GGG:Tb scintillators. These were then used to deconvolve images of an Xradia resolution test pattern taken under the same conditions. The results show that after deconvolution the MTF had been clearly improved for both the 4.6 µm- and 20 µm-thick SCFs, indicating that the image has better quality than before deconvolution. Furthermore, a PSF deconvolution was performed on mouse brain tissue projection images, and the original and deconvolution projection images were used to perform computed-tomography reconstruction; the result proved that the method was effective for improving the image quality of low-contrast samples. Therefore, this method shows promise in allowing the use of thick SCFs to improve the detection efficiency while maintaining good image quality.
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Zaluzec, N. J., and M. G. Strauss. "EELS parallel detection using 2-dimensional CCD array." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 662–63. http://dx.doi.org/10.1017/s0424820100105370.
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Conventional parallel detectors for Electron Energy Loss Spectroscopy (EELS) have been mainly based upon systems using linear photodiode arrays in a conjugate image plane of an electron spectrometer. We have developed a unique two dimensional charge coupled device (CCD) camera system which can be used as a detector for EEL spectroscopy and imaging, utilizing high sensitivity, high resolution CCD's, which are typically used in medial or astronomic imaging.The present detector system is based upon a Tektronics TK512M 512 x 512 pixel CCD array, (figure 1) which is optically coupled to a YAG:Ce single crystal scintillator. This CCD imaging system views an electron energy loss spectrum which is magnified by a quadrupole doublet lens attached to a Gatan 607 electron spectrometer on a Philips EM420 TEM as is illustrated in figure 2. The CCD controller, detector head electronics and electron optics were developed at Argonne specifically for high speed data acquisition and allow the recording of complete spectra in as short a time as 10 μsec or approximately 103 times faster than the typical 1024 pixel photodiode arrays’ thus allowing the potential for time resolved spectroscopy.