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Sample records for silicon high resolution

  1. High Resolution Silicon Deformable Mirrors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes a plan to build a prototype small stroke, high precision deformable mirror suitable for space-based operation in systems for high-resolution...

  2. High Resolution Silicon Deformable Mirrors, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposal we describe a plan to build a deformable mirror suitable for space-based operation in systems for high-resolution imaging. The prototype DM will be...

  3. The development of high resolution silicon x-ray microcalorimeters

    Science.gov (United States)

    Porter, F. S.; Kelley, R. L.; Kilbourne, C. A.

    2005-12-01

    Recently we have produced x-ray microcalorimeters with resolving powers approaching 2000 at 5.9 keV using a spare XRS microcalorimeter array. We attached 400 um square, 8 um thick HgTe absorbers using a variety of attachment methods to an XRS array and ran the detector array at temperatures between 40 and 60 mK. The best results were for absorbers attached using the standard XRS absorber-pixel thermal isolation scheme utilizing SU8 polymer tubes. In this scenario we achieved a resolution of 3.2 eV FWHM at 5.9 keV. Substituting a silicon spacer for the SU8 tubes also yielded sub-4eV results. In contrast, absorbers attached directly to the thermistor produced significant position dependence and thus degraded resolution. Finally, we tested standard 640um-square XRS detectors at reduced bias power at 50mK and achieved a resolution of 3.7eV, a 50% improvement over the XRS flight instrument. Implanted silicon microcalorimeters are a mature flight-qualified technology that still has a substantial phase space for future development. We will discuss these new high resolution results, the various absorber attachment schemes, planned future improvements, and, finally, their relevance to future high resolution x-ray spectrometers including Constellation-X.

  4. High resolution silicon detectors for colliding beam physics

    International Nuclear Information System (INIS)

    Amendolia, S.R.; Bedeschi, F.; Bertolucci, E.; Bettoni, D.; Bosisio, L.; Bottigli, U.; Bradaschia, C.; Dell'Orso, M.; Fidecaro, F.; Foa, L.; Focardi, E.; Giannetti, P.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Raso, G.; Ristori, L.; Scribano, A.; Stefanini, A.; Tenchini, R.; Tonelli, G.; Triggiani, G.

    1984-01-01

    Resolution and linearity of the position measurement of Pisa multi-electrode silicon detectors are presented. The detectors are operated in slightly underdepleted mode and take advantage of their intrinsic resistivity for resistive charge partition between adjacent strips. 22 μm resolution is achieved with readout lines spaced 300 μm. Possible applications in colliding beam experiments for the detection of secondary vertices are discussed. (orig.)

  5. Progress on the Fabrication of High Resolution and Lightweight Monocrystalline Silicon X-ray Mirrors

    Science.gov (United States)

    Riveros, Raul E.; Biskach, Michael P.; Allgood, Kim D.; Mazzarella, James R.; Sharpe, Marton V.; Zhang, William W.

    2016-01-01

    Monocrystalline silicon is an excellent X-ray mirror substrate material due to its high stiffness, low density, high thermal conductivity, zero internal stress, and commercial availability. Our work at NASA Goddard Space Flight Center focuses on identifying and developing a manufacturing process to produce high resolution and lightweight X-ray mirror segments in a cost and time effective manner. Previous efforts focused on demonstrating the feasibility of cylindrical silicon mirror polishing and lightweighting. Present efforts are aimed towards producing true paraboloidal and hyperboloidal mirror surfaces on the lightweight silicon segments. This paper presents results from these recent investigations, including a mirror which features a surface quality sufficient for a 3 arcsecond telescope.

  6. High-resolution mapping of quantum efficiency of silicon photodiode via optical-feedback laser microthermography

    International Nuclear Information System (INIS)

    Cemine, Vernon Julius; Blanca, Carlo Mar; Saloma, Caesar

    2006-01-01

    We map the external quantum efficiency (QE) distribution of a silicon photodiode (PD) sample via a thermographic imaging technique based on optical-feedback laser confocal microscopy. An image pair consisting of the confocal reflectance image and the 2D photocurrent map is simultaneously acquired to delineate the following regions of interest on the sample: the substrate, the n-type region, the pn overlay, and the bonding pad. The 2D QE distribution is derived from the photocurrent map to quantify the optical performance of these sites. The thermal integrity of the sample is then evaluated by deriving the rate of change of QE with temperature T at each point on the silicon PD. These gradient maps function not only as stringent measures of local thermal QE activity but they also expose probable defect locations on the sample at high spatial resolution - a capability that is not feasible with existing bulk measurement techniques

  7. High-resolution patterning of graphene by screen printing with a silicon stencil for highly flexible printed electronics.

    Science.gov (United States)

    Hyun, Woo Jin; Secor, Ethan B; Hersam, Mark C; Frisbie, C Daniel; Francis, Lorraine F

    2015-01-07

    High-resolution screen printing of pristine graphene is introduced for the rapid fabrication of conductive lines on flexible substrates. Well-defined silicon stencils and viscosity-controlled inks facilitate the preparation of high-quality graphene patterns as narrow as 40 μm. This strategy provides an efficient method to produce highly flexible graphene electrodes for printed electronics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. NLTE ANALYSIS OF HIGH-RESOLUTION H -BAND SPECTRA. I. NEUTRAL SILICON

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Junbo; Shi, Jianrong; Liu, Chao [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012 (China); Pan, Kaike [Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States); Prieto, Carlos Allende, E-mail: sjr@bao.ac.cn [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain)

    2016-12-20

    We investigated the reliability of our silicon atomic model and the influence of non-local thermodynamical equilibrium (NLTE) on the formation of neutral silicon (Si i) lines in the near-infrared (near-IR) H -band. We derived the differential Si abundances for 13 sample stars with high-resolution H -band spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE), as well as from optical spectra, both under local thermodynamical equilibrium (LTE) and NLTE conditions. We found that the differences between the Si abundances derived from the H -band and from optical lines for the same stars are less than 0.1 dex when the NLTE effects are included, and that NLTE reduces the line-to-line scatter in the H -band spectra for most sample stars. These results suggest that our Si atomic model is appropriate for studying the formation of H -band Si lines. Our calculations show that the NLTE corrections of the Si i H -band lines are negative, i.e., the final Si abundances will be overestimated in LTE. The corrections for strong lines depend on surface gravity, and tend to be larger for giants, reaching ∼−0.2 dex in our sample, and up to ∼−0.4 dex in extreme cases of APOGEE targets. Thus, the NLTE effects should be included in deriving silicon abundances from H -band Si i lines, especially for the cases where only strong lines are available.

  9. Lightweight and High-Resolution Single Crystal Silicon Optics for X-ray Astronomy

    Science.gov (United States)

    Zhang, William W.; Biskach, Michael P.; Chan, Kai-Wing; Mazzarella, James R.; McClelland, Ryan S.; Riveros, Raul E.; Saha, Timo T.; Solly, Peter M.

    2016-01-01

    We describe an approach to building mirror assemblies for next generation X-ray telescopes. It incorporates knowledge and lessons learned from building existing telescopes, including Chandra, XMM-Newton, Suzaku, and NuSTAR, as well as from our direct experience of the last 15 years developing mirror technology for the Constellation-X and International X-ray Observatory mission concepts. This approach combines single crystal silicon and precision polishing, thus has the potential of achieving the highest possible angular resolution with the least possible mass. Moreover, it is simple, consisting of several technical elements that can be developed independently in parallel. Lastly, it is highly amenable to mass production, therefore enabling the making of telescopes of very large photon collecting areas.

  10. Determination of silicon and aluminum in silicon carbide nanocrystals by high-resolution continuum source graphite furnace atomic absorption spectrometry.

    Science.gov (United States)

    Dravecz, Gabriella; Bencs, László; Beke, Dávid; Gali, Adam

    2016-01-15

    The determination of Al contaminant and the main component Si in silicon carbide (SiC) nanocrystals with the size-distribution of 1-8nm dispersed in an aqueous solution was developed using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS-GFAAS). The vaporization/atomization processes were investigated in a transversally heated graphite atomizer by evaporating solution samples of Al and Si preserved in various media (HCl, HNO3). For Si, the best results were obtained by applying a mixture of 5µg Pd plus 5µg Mg, whereas for Al, 10µg Mg (each as nitrate solution) was dispensed with the samples, but the results obtained without modifier were found to be better. This way a maximum pyrolysis temperature of 1200°C for Si and 1300°C for Al could be used, and the optimum (compromise) atomization temperature was 2400°C for both analytes. The Si and Al contents of different sized SiC nanocrystals, dispersed in aqueous solutions, were determined against aqueous (external) calibration standards. The correlation coefficients (R values) of the calibrations were found to be 0.9963 for Si and 0.9991 for Al. The upper limit of the linear calibration range was 2mg/l Si and 0.25mg/l Al. The limit of detection was 3µg/l for Si and 0.5µg/l for Al. The characteristic mass (m0) was calculated to be 389pg Si and 6.4pg Al. The Si and Al content in the solution samples were found to be in the range of 1.0-1.7mg/l and 0.1-0.25mg/l, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Construction and Evaluation of a High Resolution Silicon Microstrip Tracking Detector, and, Utilization to Determine Interaction Vertices

    Energy Technology Data Exchange (ETDEWEB)

    Mathew, Prakash Parayil [Carnegie Mellon U.

    1997-01-01

    A 20 plane, 47K channel silicon microstrip vertex detector was built for the charm baryon experiment 781 (SELEX) at Fermilab. The detector is taking data with an average vertex transverse resolution of 6 microns. The measurement and multiple scattering errors are well understood and have been parametrized. The mass resolution of reconstructed $\\Sigma^+$ and $\\Sigma^-$ hyperons produced at 540-640 GeV /c is consistent with silicon detector resolutions. The vertex detector has been used to resolve primary and secondary vertices and this high precision information is being used in the experiment's realtime online trigger. Flawless operation over 14 months and the long-term stability of the efficiency, alignment and accuracy demonstrates successful integration of hardware and software.

  12. Online readout and control unit for high-speed / high resolution readout of silicon tracking detectors

    International Nuclear Information System (INIS)

    Buerger, J.; Hansen, K.; Lange, W.; Nowak, T.; Prell, S.; Zimmermann, W.

    1996-09-01

    We are describing a high speed VME readout and control module developed and presently working at the H1 experiment at DESY in Hamburg. It has the capability to read out 4 x 2048 analogue data channels at sampling rates up to 10 MHz with a dynamic input range of 1 V. The nominal resolution of the A/D converters can be adjusted between 8 and 12 bit. At the latter resolution we obtain signal-to-noise ratio better than 61.4 dB at a conversion rate of 5 MSps. At this data rate all 8192 detector channels can be read out to the internal raw data memory and VME interface within about 410 μs and 510 μs, respectively. The pedestal subtracted signals can be analyzed on-line. At a raw data hit occupation of 10%, the VME readout time is 50 μs per module. Each module provides four complementary CMOS signals to control the front-end electronics and four independent sets of power supplies for analogue and digital voltages (10 V, 100 mA) to drive the front-end electronics and for the bias voltage (100 V, 1.2 mA) to assure the full functionality of the detectors and the readout. (orig.)

  13. Investigation of charm production in hadronic interactions using high-resolution silicon detectors

    CERN Multimedia

    2002-01-01

    The experiment is designed to measure the lifetime of the $F$ and $\\Lambda_{C}$.\\\\ The first level trigger uses scintillator and Cerenkov hodoscope information to select events with at least two particles of opposite charge and compatible with being a kaon or proton.\\\\ The second-level trigger makes use of the FAMP microprocessor system to determine the momenta of the selected particles using the information from 5 MWPC planes, assuming that the particles come from a point target. Only those events are accepted where the selected particles had momenta in the range of the momentum bands given by the Cerenkov counter thresholds.\\\\ The full kinematic reconstruction of the charm decays is achieved using the information from the different parts of the spectrometer: \\\\1) a vertex telescope of eight planes of 5 $\\mu$m resolution silicon strip counters and two charge coupled devices having a spatial resolution of $\\simeq 5 \\mu$m in x and y, \\\\2) a beam telescope of seven planes of 3 $\\mu$m resolution silicon strip c...

  14. Direct measurement high resolution wide range extreme temperature optical sensor using an all-silicon carbide probe.

    Science.gov (United States)

    Sheikh, Mumtaz; Riza, Nabeel A

    2009-05-01

    We propose and demonstrate a temperature sensing method using an all-silicon carbide probe that combines wavelength-tuned signal processing for coarse measurements and classical Fabry-Perot etalon peak shift for fine measurements. This method gives direct unambiguous temperature measurements with a high temperature resolution over a wide temperature range. Specifically, temperature measurements from room temperature to 1000 degrees C are experimentally demonstrated with an estimated resolution varying from 0.66 degrees C at room temperature to 0.12 degrees C at 1000 degrees C. The proposed sensor has applications in next-generation greener gas turbines for power production.

  15. Development of a low-noise readout ASIC for Silicon Drift Detectors in high energy resolution X-ray spectrometry

    Science.gov (United States)

    Atkin, E.; Levin, V.; Malankin, E.; Shumikhin, V.

    2017-03-01

    ASIC with a low-noise readout channel for Silicon Drift Detectors in high energy resolution X-ray spectrometry was designed and prototyped in the AMS 350 nm CMOS process via Europractice as a miniASIC. For the analog readout channel tests there was used the detector module SDD-10-130-PTW LTplus-ic (PNDetector GmbH). The measured energy resolution of this module with the designed readout channel: 200 eV (FWHM) at 55Fe, -16 °C, 1 kcps and a peaking time of 8 μs.

  16. The development of a high-resolution scintillating fiber tracker with silicon photomultiplier readout

    International Nuclear Information System (INIS)

    Roper Yearwood, Gregorio

    2013-01-01

    In this work I present the design and test results for a novel, modular tracking detector from scintillating fibers which are read out by silicon photomultiplier (SiPM) arrays. The detector modules consist of 0.25 mm thin scintillating fibers which are closely packed in five-layer ribbons. Two ribbons are fixed to both sides of a carbon-fiber composite structure. Custom made SiPM arrays with a photo-detection efficiency of about 50% read out the fibers. Several 860 mm long and 32 mm wide tracker modules were tested in a secondary 12 GeV/c beam at the PS facilities, CERN in November of 2009. During this test a spatial resolution better than 0.05 mm at an average light yield of about 20 photons for a minimum ionizing particle was determined. This work details the characterization of scintillating fibers and silicon photomultipliers of different make and model. It gives an overview of the production of scintillating fiber modules. The behavior of detector modules during the test-beam is analyzed in detail and different options for the front-end electronics are compared. Furthermore, the implementation of the proposed tracking detector from scintillating fibers within the scope of the PERDaix experiment is discussed. The PERDaix detector is a permanent magnet spectrometer with a weight of 40 kg. It consists of 8 tracking detector layers from scintillating fibers, a time-of-flight detector from plastic scintillator bars with silicon photomultiplier readout and a transition radiation detector from an irregular fleece radiator and Xe/CO 2 filled proportional counting tubes. The PERDaix detector was launched with a helium balloon within the scope of the ''Balloon-Experiments for University Students'' (BEXUS) program from Kiruna, Sweden in November 2010. For a few hours PERDaix reached an altitude of 33 km and measured cosmic rays. In May 2011, the PERDaix detector was characterized during a test-beam at the PS-facilities at CERN. This work introduces methods for event

  17. Fabrication of high resolution and lightweight monocrystalline silicon x-ray mirrors

    Science.gov (United States)

    Riveros, Raul E.; Kolos, Linette D.; Mazzarella, James R.; McKeon, Kevin P.; Zhang, William W.

    2015-09-01

    Monocrystalline silicon as an x-ray mirror substrate material promises significant improvements over the x- ray mirror technologies used to date, since it is mechanically stiff, stress-free, highly thermally conductive, and widely commercially available. Producing highly accurate and lightweight x-ray mirrors from monocrystalline silicon requires a unique and specialized manufacturing process capable of producing mirrors quickly and cost effectively. The identification, development, and testing of this process is the focus of the work described in this proceeding. Monocrystalline silicon blocks were obtained, and a variety of processes (wire electro-discharge machining, etching, polishing) were applied to generate an accurate and stress-free cylindrical or Wolter-I mirror surface. The mirror surface is then sliced off at a thickness of RMS slope errors. Furthermore, our experiments suggest that this mirror production process requires ~2 days to produce a mirror segment and is easily integrated into a cost-reducing parallel processing scheme. Presently, there is strong evidence that the mirror production process described in this paper will meet the stringent requirements of future x-ray missions.

  18. High-resolution spectroscopy and time-resolved study of electroluminescence of Er-1 center in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Kudryavtsev, K.E., E-mail: konstantin@ipm.sci-nnov.r [Institute for Physics of Microstructures, GSP-105, 603950 Nizhniy Novgorod (Russian Federation); Shmagin, V.B.; Shengurov, D.V.; Krasilnik, Z.F. [Institute for Physics of Microstructures, GSP-105, 603950 Nizhniy Novgorod (Russian Federation)

    2009-12-15

    High-resolution and time-resolved measurements on the electroluminescence from Er-doped silicon diode structures with Er-1 center, grown with sublimation molecular beam epitaxy, have been performed within the temperature interval 30-120 K. We find emission lines with full width down to 0.2 cm{sup -1} (25 mueV) at 30 K, the narrowest lines ever observed in Si:Er electroluminescence spectra, and excitation cross-section of 4x1{sup -15} cm{sup 2}. Auger-deexcitation of Er{sup 3+} ions with the activation energy of 16 meV was found to be the only deexcitation process in these structures and no 'back-transfer' deexcitation was observed. Due to ultra narrow emission lines and a high excitation cross-section such diode structures are promising for realization of an electrically pumped silicon-based laser.

  19. High-resolution strain sensing on steel by Silicon-On-Insulator flexural resonators fabricated with chip-level vacuum packaging

    OpenAIRE

    Belsito, Luca; Ferri, Matteo; Mancarella, Fulvio; Roncaglia, Alberto; Yan, Jize; Seshia, A. Ashwin; Soga, Kenichi

    2013-01-01

    This paper reports on the fabrication and characterization of high-resolution strain sensors for steel based on Silicon On Insulator flexural resonators manufactured with chip-level LPCVD vacuum packaging. The sensors present high sensitivity (120 Hz/??), very high resolution (4 n?), low drift, and near-perfect reversibility in bending tests performed in both tensile and compressive strain regimes.

  20. High resolution medium energy ion scattering study of silicon oxidation and oxy nitridation

    International Nuclear Information System (INIS)

    Gusev, E.P.; Lu, H.C.; Garfunkel, E.; Gustafsson, T.

    1998-01-01

    Full text: Silicon oxide is likely to remain the material of choice for gate oxides in microelectronics for the foreseeable future. As device become ever smaller and faster, the thickness of these layers in commercial products is predicted to be less than 50 Angstroms in just a few years. An understanding of such devices will therefore likely to be based on microscopic concepts and should now be investigated by atomistic techniques. With medium energy ion scattering (MEIS) using an electrostatic energy analyzer, depth profiling of thin (<60 Angstroms) silicon oxide films on Si(100) with 3 - 5 Angstroms depth resolution in the near region has been done. The growth mechanism of thin oxide films on Si(100) has been studied, using sequential oxygen isotope exposures. It is found that the oxide films are stoichiometric to within approx. 10 Angstroms of the interface. It is also found that the oxidation reactions occur at the surface, in the transition region and at interface, with only the third region being included in the conventional (Deal-Grove) model for oxide formation. Nitrogen is sometimes added to gate oxides, as it has been found empirically that his improves some of the electrical properties. The role, location and even the amount of nitrogen that exists in such films are poorly understood, and represent interesting analytical challenges. MEIS data will be presented that address these questions, measured for a number of different processing conditions. We have recently demonstrated how to perform nitrogen nano-engineering in such ultrathin gate dielectrics, and these results will also be discussed

  1. High-resolution study of x-ray resonant Raman scattering at the k edge of silicon

    OpenAIRE

    Szlachetko, Jakub; Dousse, Jean-Claude; Hoszowska, J.; Pajek, M.; Barrett, R.; Berset, Michel; Fennane, Karima; Kubala-Kukus, A.; Szlachetko, Monika

    2007-01-01

    We report on the first high-resolution measurements of the K x-ray resonant Raman scattering (RRS) in Si. The measured x-ray RRS spectra, interpreted using the Kramers-Heisenberg approach, revealed spectral features corresponding to electronic excitations to the conduction and valence bands in silicon. The total cross sections for the x-ray RRS at the 1s absorption edge and the 1s-3p excitation were derived. The Kramers-Heisenberg formalism was found to reproduce quite well the x-ray RRS spec...

  2. Time-Efficient High-Resolution Large-Area Nano-Patterning of Silicon Dioxide

    DEFF Research Database (Denmark)

    Lin, Li; Ou, Yiyu; Aagesen, Martin

    2017-01-01

    A nano-patterning approach on silicon dioxide (SiO2) material, which could be used for the selective growth of III-V nanowires in photovoltaic applications, is demonstrated. In this process, a silicon (Si) stamp with nanopillar structures was first fabricated using electron-beam lithography (EBL...

  3. Modeling and feasibility study of a high resolution numerical time encoder in silicon and gallium arsenide integrated technologies

    International Nuclear Information System (INIS)

    Fota, C.

    1996-12-01

    This work is part of an evaluation of a high resolution time encoder implemented as a circular vernier. Two integrated technologies have been used, silicon CMOS and GaAs HEMT. After a short survey of the existing time encoding techniques, we propose a digital method using a circular time vernier built around two ring oscillators. We present the benefits of such a technique, a detailed analysis of the vernier, and simulation results. Technological spreads that are critical for such a time encoder have been measured on a silicon ship with 0.8 micron gate length CMOS technology. The achievable resolution is derived from the results. The frequencies dictated by the circular vernier architecture reach a few hundred Megahertz, the chip layout is thus critical, as showed from the measurements on a 0.3 micron GaAs HEMT chip. Measurements are compared with simulations for each chip. Several other circular vernier layouts are proposed in order to improve the results. A mathematical model of a calibration phase lock loop of the ring oscillators on a reference clock is also presented. (author)

  4. High spatial resolution radiation detectors based on hydrogenated amorphous silicon and scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Tao [Univ. of California, Berkeley, CA (United States). Dept. of Engineering-Nuclear Engineering

    1995-05-01

    Hydrogenated amorphous silicon (a-Si:H) as a large-area thin film semiconductor with ease of doping and low-cost fabrication capability has given a new impetus to the field of imaging sensors; its high radiation resistance also makes it a good material for radiation detectors. In addition, large-area microelectronics based on a-Si:H or polysilicon can be made with full integration of peripheral circuits, including readout switches and shift registers on the same substrate. Thin a-Si:H p-i-n photodiodes coupled to suitable scintillators are shown to be suitable for detecting charged particles, electrons, and X-rays. The response speed of CsI/a-Si:H diode combinations to individual particulate radiation is limited by the scintillation light decay since the charge collection time of the diode is very short (< 10ns). The reverse current of the detector is analyzed in term of contact injection, thermal generation, field enhanced emission (Poole-Frenkel effect), and edge leakage. A good collection efficiency for a diode is obtained by optimizing the p layer of the diode thickness and composition. The CsI(Tl) scintillator coupled to an a-Si:H photodiode detector shows a capability for detecting minimum ionizing particles with S/N ~20. In such an arrangement a p-i-n diode is operated in a photovoltaic mode (reverse bias). In addition, a p-i-n diode can also work as a photoconductor under forward bias and produces a gain yield of 3--8 for shaping times of 1 {micro}s. The mechanism of the formation of structured CsI scintillator layers is analyzed. Initial nucleation in the deposited layer is sensitive to the type of substrate medium, with imperfections generally catalyzing nucleation. Therefore, the microgeometry of a patterned substrate has a significant effect on the structure of the CsI growth.

  5. High spatial resolution radiation detectors based on hydrogenated amorphous silicon and scintillator

    International Nuclear Information System (INIS)

    Jing, T.; Lawrence Berkeley Lab., CA

    1995-05-01

    Hydrogenated amorphous silicon (a-Si:H) as a large-area thin film semiconductor with ease of doping and low-cost fabrication capability has given a new impetus to the field of imaging sensors; its high radiation resistance also makes it a good material for radiation detectors. In addition, large-area microelectronics based on a-Si:H or polysilicon can be made with full integration of peripheral circuits, including readout switches and shift registers on the same substrate. Thin a-Si:H p-i-n photodiodes coupled to suitable scintillators are shown to be suitable for detecting charged particles, electrons, and X-rays. The response speed of CsI/a-Si:H diode combinations to individual particulate radiation is limited by the scintillation light decay since the charge collection time of the diode is very short (< 10ns). The reverse current of the detector is analyzed in term of contact injection, thermal generation, field enhanced emission (Poole-Frenkel effect), and edge leakage. A good collection efficiency for a diode is obtained by optimizing the p layer of the diode thickness and composition. The CsI(Tl) scintillator coupled to an a-Si:H photodiode detector shows a capability for detecting minimum ionizing particles with S/N ∼20. In such an arrangement a p-i-n diode is operated in a photovoltaic mode (reverse bias). In addition, a p-i-n diode can also work as a photoconductor under forward bias and produces a gain yield of 3--8 for shaping times of 1 micros. The mechanism of the formation of structured CsI scintillator layers is analyzed. Initial nucleation in the deposited layer is sensitive to the type of substrate medium, with imperfections generally catalyzing nucleation. Therefore, the microgeometry of a patterned substrate has a significant effect on the structure of the CsI growth

  6. High resolution x-ray scattering studies of strain in epitaxial thin films of yttrium silicide grown on silicon (111)

    International Nuclear Information System (INIS)

    Marthinez-Miranda, L.J.; Santiago-Aviles, J.J.; Siegal, M.P.; Graham, W.R.; Heiney, P.A.

    1990-01-01

    The authors have used high resolution grazing incidence x-ray scattering (GIXS) to study the in- plane and out-of-plane structure of epitaxial YSi 2-x films grown on Si(111), with thicknesses ranging from 85 Angstrom to 510 Angstrom. Their results indicate that the films are strained, and that film strain increases as a function of thickness, with lattice parameters varying from a = 3.846 Angstrom/c = 4.142 Angstrom for the 85 Angstrom film to a = 3.877 Angstrom/c = 4.121 Angstrom for the 510 Angstrom film. The authors correlate these results with an increase in pinhole areal coverage as a function of thickness. In addition, the authors' measurements show no evidence for the existence of ordered silicon vacancies in the films

  7. Silicon photomultiplier arrays - a novel photon detector for a high resolution tracker produced at FBK-irst, Italy

    International Nuclear Information System (INIS)

    Greim, R.; Gast, H.; Kirn, T.; Olzem, J.; Yearwood, G. Roper; Schael, S.; Zimmermann, N.; Ambrosi, G.; Azzarello, P.; Battiston, R.; Piemonte, C.

    2009-01-01

    A silicon photomultiplier (SiPM) array has been developed at FBK-irst [Piemonte C., Nucl. Instrum. Methods A, 568 (2006) 224; Piemonte C. et al., IEEE Trans. Nucl. Sci., 54 (2007) 236] having 32 channels and a dimension of 8.0x1.1mm 2 . Each 250 μm wide channel is subdivided into 5x22 rectangularly arranged pixels. These sensors are developed to read out a modular high resolution scintillating fiber tracker. Key properties like breakdown voltage, gain and photon detection efficiency (PDE) are found to be homogeneous over all 32 channels of an SiPM array. This could make scintillating fiber trackers with SiPM array readout a promising alternative to available tracker technologies, if noise properties and the PDE are improved.

  8. Silicon photomultiplier arrays - a novel photon detector for a high resolution tracker produced at FBK-irst, Italy

    Energy Technology Data Exchange (ETDEWEB)

    Greim, R.; Gast, H.; Kirn, T.; Olzem, J.; Yearwood, G. Roper; Schael, S.; Zimmermann, N. [I. Physikalisches Institut B, RWTH Aachen University, 52074 Aachen (Germany); Ambrosi, G.; Azzarello, P. [Dipartimento di Fisica, Universita di Perugia, 06123 Perugia (Italy); Battiston, R. [Dipartimento di Fisica, Universita di Perugia, 06123 Perugia (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, 06123 Perugia (Italy); Piemonte, C. [Fondazione Bruno Kessler - Istituto per la Ricerca Scientifica e tecnologica, 38050 Trento (Italy)

    2009-12-15

    A silicon photomultiplier (SiPM) array has been developed at FBK-irst [Piemonte C., Nucl. Instrum. Methods A, 568 (2006) 224; Piemonte C. et al., IEEE Trans. Nucl. Sci., 54 (2007) 236] having 32 channels and a dimension of 8.0x1.1mm{sup 2}. Each 250 mum wide channel is subdivided into 5x22 rectangularly arranged pixels. These sensors are developed to read out a modular high resolution scintillating fiber tracker. Key properties like breakdown voltage, gain and photon detection efficiency (PDE) are found to be homogeneous over all 32 channels of an SiPM array. This could make scintillating fiber trackers with SiPM array readout a promising alternative to available tracker technologies, if noise properties and the PDE are improved.

  9. Raman mapping of microcrystalline silicon thin films with high spatial resolution

    Czech Academy of Sciences Publication Activity Database

    Ledinský, Martin; Vetushka, Aliaksi; Stuchlík, Jiří; Fejfar, Antonín; Kočka, Jan

    2010-01-01

    Roč. 7, 3-4 (2010), s. 704-707 ISSN 1862-6351 R&D Projects: GA MŠk(CZ) LC06040; GA AV ČR KAN400100701; GA MŠk LC510; GA AV ČR(CZ) IAA100100902 Institutional research plan: CEZ:AV0Z10100521 Keywords : Raman * atomic force microscopy * microcrystalline silicon Subject RIV: BM - Solid Matter Physics ; Magnetism http://www3.interscience.wiley.com/journal/123277609/abstract

  10. Fabrication of High Resolution Lightweight X-ray Mirrors Using Mono-crystalline Silicon Project

    Data.gov (United States)

    National Aeronautics and Space Administration — "Three factors characterize an X-ray optics fabrication technology: angular resolution, effective area per unit mass, and production cost per unit effective...

  11. arXiv Time resolution of silicon pixel sensors

    CERN Document Server

    Riegler, W.

    2017-11-21

    We derive expressions for the time resolution of silicon detectors, using the Landau theory and a PAI model for describing the charge deposit of high energy particles. First we use the centroid time of the induced signal and derive analytic expressions for the three components contributing to the time resolution, namely charge deposit fluctuations, noise and fluctuations of the signal shape due to weighting field variations. Then we derive expressions for the time resolution using leading edge discrimination of the signal for various electronics shaping times. Time resolution of silicon detectors with internal gain is discussed as well.

  12. Determination of silicon in biomass and products of pyrolysis process via high-resolution continuum source atomic absorption spectrometry.

    Science.gov (United States)

    Nakadi, Flávio V; Prodanov, Caroline; Boschetti, Wiliam; Vale, Maria Goreti R; Welz, Bernhard; de Andrade, Jailson B

    2018-03-01

    Thermochemical processes can convert the biomass into fuels, such as bio-oil. The biomass submitted to pyrolysis process, such as fibers, are generally rich in silicon, an element that can lead to damages in an engine when there is high concentration in a fuel. High-resolution continuum source atomic absorption spectrometry (HR-CS AAS) is an interesting alternative for Si determination in the products and byproducts of the pyrolysis process because, besides the flame (F) and graphite furnace (GF) atomizers, it has enhanced the application of direct analysis of solid samples (SS) within GF. This study aimed the development of methods to determine Si in biomass samples, their products and byproducts using HR-CS AAS. A high-resolution continuum source atomic absorption spectrometer contrAA 700 equipped with F and GF atomizers was used throughout the study. HR-CS F AAS (λ = 251.611nm, 1 detection pixel, N 2 O/C 2 H 2 flame) was used to evaluate Si content in biomass and ash, after a microwave-assisted acid digestion with HNO 3 and HF. HR-CS GF AAS (T pyr = 1400°C, T atom = 2650°C) has evaluated Si in pyrolysis water and bio-oil at 251.611nm, and in peach pit biomass and ash at 221.174nm using SS, both wavelengths with 1 detection pixel. Rhodium (300μg) was applied as permanent modifier and 10μgPd + 6μg Mg were pipetted onto the standards/samples at each analysis. Three different biomass samples were studied: palm tree fiber, coconut fiber and peach pit, and three certified reference materials (CRM) were used to verify the accuracy of the methods. The figures of merit were LOD 0.09-20mgkg -1 , and LOQ 0.3-20mgkg -1 , considering all the methods. There were no significant differences between the CRM certified values and the determined ones, using a Student t-test with a confidence interval of 95% (n = 5). Si concentration ranged from 0.11-0.92% mm -1 , 1.1-1.7mgkg -1 , 3.3-13mgkg -1 , and 0.41-1.4%mm -1 , in biomass, bio-oil, pyrolysis water and ash, respectively

  13. A micron resolution optical scanner for characterization of silicon detectors

    International Nuclear Information System (INIS)

    Shukla, R. A.; Dugad, S. R.; Gopal, A. V.; Gupta, S. K.; Prabhu, S. S.; Garde, C. S.

    2014-01-01

    The emergence of high position resolution (∼10 μm) silicon detectors in recent times have highlighted the urgent need for the development of new automated optical scanners of micron level resolution suited for characterizing microscopic features of these detectors. More specifically, for the newly developed silicon photo-multipliers (SiPM) that are compact, possessing excellent photon detection efficiency with gain comparable to photo-multiplier tube. In a short time, since their invention the SiPMs are already being widely used in several high-energy physics and astrophysics experiments as the photon readout element. The SiPM is a high quantum efficiency, multi-pixel photon counting detector with fast timing and high gain. The presence of a wide variety of photo sensitive silicon detectors with high spatial resolution requires their performance evaluation to be carried out by photon beams of very compact spot size. We have designed a high resolution optical scanner that provides a monochromatic focused beam on a target plane. The transverse size of the beam was measured by the knife-edge method to be 1.7 μm at 1 − σ level. Since the beam size was an order of magnitude smaller than the typical feature size of silicon detectors, this optical scanner can be used for selective excitation of these detectors. The design and operational details of the optical scanner, high precision programmed movement of target plane (0.1 μm) integrated with general purpose data acquisition system developed for recording static and transient response photo sensitive silicon detector are reported in this paper. Entire functionality of scanner is validated by using it for selective excitation of individual pixels in a SiPM and identifying response of active and dead regions within SiPM. Results from these studies are presented in this paper

  14. High-resolution and Fast-response Fiber-optic Temperature Sensor Using Silicon Fabry-Perot Cavity

    Science.gov (United States)

    2015-03-23

    sensor using silicon Fabry -Pérot cavity 0601153N 73-4951-05-5 Guigen Liu, Ming Han, and Weilin Hou Naval Research Laboratory Oceanography Division...VA 22203-1995 ONR Approved for public release, distribution is unlimited. We report a fiber-optic sensor based on a silicon Fabry -Pérot cavity...silicon Fabry -Pérot cavity Guigen Liu,1 Ming Han,1,* and Weilin Hou2 1Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln

  15. Characterizing Grain-Oriented Silicon Steel Sheet Using Automated High-Resolution Laue X-ray Diffraction

    Science.gov (United States)

    Lynch, Peter; Barnett, Matthew; Stevenson, Andrew; Hutchinson, Bevis

    2017-11-01

    Controlling texture in grain-oriented (GO) silicon steel sheet is critical for optimization of its magnetization performance. A new automated laboratory system, based on X-ray Laue diffraction, is introduced as a rapid method for large scale grain orientation mapping and texture measurement in these materials. Wide area grain orientation maps are demonstrated for both macroetched and coated GO steel sheets. The large secondary grains contain uniform lattice rotations, the origins of which are discussed.

  16. Design and implementation of an integrated architecture for massive parallel data treatment of analogue signals supplied by silicon detectors of very high spatial resolution

    International Nuclear Information System (INIS)

    Michel, J.

    1993-02-01

    This doctorate thesis studies an integrated architecture designed to a parallel massive treatment of analogue signals supplied by silicon detectors of very high spatial resolution. The first chapter is an introduction presenting the general outline and the triggering conditions of the spectrometer. Chapter two describes the operational structure of a microvertex detector made of Si micro-plates associated to the measuring chains. Information preconditioning is related to the pre-amplification stage, to the pile-up effects and to the reduction in the time characteristic due to the high counting rates. The chapter three describes the architecture of the analogue delay buffer, makes an analysis of the intrinsic noise and presents the operational testings and input/output control operations. The fourth chapter is devoted to the description of the analogue pulse shape processor and gives also the testings and the corresponding measurements on the circuit. Finally, the chapter five deals with the simplest modeling of the entire conditioning chain. Also, the testings and measuring procedures are here discussed. In conclusion the author presents some prospects for improving the signal-to-noise ratio by summation of the de-convoluted micro-paths. 78 refs., 78 figs., 1 annexe

  17. High Resolution Elevation Contours

    Data.gov (United States)

    Minnesota Department of Natural Resources — This dataset contains contours generated from high resolution data sources such as LiDAR. Generally speaking this data is 2 foot or less contour interval.

  18. High-End Silicon PDICs

    Directory of Open Access Journals (Sweden)

    H. Zimmermann

    2008-05-01

    Full Text Available An overview on integrated silicon photodiodes and photodiode integrated circuits (PDICs or optoelectronic integrated circuits (OEICs for optical storage systems (OSS and fiber receivers is given. It is demonstrated, that by using low-cost silicon technologies high-performance OEICs being true competitors for some III/V-semiconductor OEICs can be realized. OSS-OEICs with bandwidths of up to 380 MHz and fiber receivers with maximum data rates of up to 11 Gbps are described. Low-cost data comm receivers for plastic optical fibers (POF as well as new circuit concepts for OEICs and highly parallel optical receivers are described also in the following.

  19. Ultra high resolution tomography

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, W.S.

    1994-11-15

    Recent work and results on ultra high resolution three dimensional imaging with soft x-rays will be presented. This work is aimed at determining microscopic three dimensional structure of biological and material specimens. Three dimensional reconstructed images of a microscopic test object will be presented; the reconstruction has a resolution on the order of 1000 A in all three dimensions. Preliminary work with biological samples will also be shown, and the experimental and numerical methods used will be discussed.

  20. Catastrophic degradation of the interface of epitaxial silicon carbide on silicon at high temperatures

    Science.gov (United States)

    Pradeepkumar, Aiswarya; Mishra, Neeraj; Kermany, Atieh Ranjbar; Boeckl, John J.; Hellerstedt, Jack; Fuhrer, Michael S.; Iacopi, Francesca

    2016-07-01

    Epitaxial cubic silicon carbide on silicon is of high potential technological relevance for the integration of a wide range of applications and materials with silicon technologies, such as micro electro mechanical systems, wide-bandgap electronics, and graphene. The hetero-epitaxial system engenders mechanical stresses at least up to a GPa, pressures making it extremely challenging to maintain the integrity of the silicon carbide/silicon interface. In this work, we investigate the stability of said interface and we find that high temperature annealing leads to a loss of integrity. High-resolution transmission electron microscopy analysis shows a morphologically degraded SiC/Si interface, while mechanical stress measurements indicate considerable relaxation of the interfacial stress. From an electrical point of view, the diode behaviour of the initial p-Si/n-SiC junction is catastrophically lost due to considerable inter-diffusion of atoms and charges across the interface upon annealing. Temperature dependent transport measurements confirm a severe electrical shorting of the epitaxial silicon carbide to the underlying substrate, indicating vast predominance of the silicon carriers in lateral transport above 25 K. This finding has crucial consequences on the integration of epitaxial silicon carbide on silicon and its potential applications.

  1. Catastrophic degradation of the interface of epitaxial silicon carbide on silicon at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Pradeepkumar, Aiswarya; Mishra, Neeraj; Kermany, Atieh Ranjbar; Iacopi, Francesca [Queensland Micro and Nanotechnology Centre and Environmental Futures Research Institute, Griffith University, Nathan QLD 4111 (Australia); Boeckl, John J. [Materials and Manufacturing Directorate, Air Force Research Laboratories, Wright-Patterson Air Force Base, Ohio 45433 (United States); Hellerstedt, Jack; Fuhrer, Michael S. [Monash Centre for Atomically Thin Materials, Monash University, Monash, VIC 3800 (Australia)

    2016-07-04

    Epitaxial cubic silicon carbide on silicon is of high potential technological relevance for the integration of a wide range of applications and materials with silicon technologies, such as micro electro mechanical systems, wide-bandgap electronics, and graphene. The hetero-epitaxial system engenders mechanical stresses at least up to a GPa, pressures making it extremely challenging to maintain the integrity of the silicon carbide/silicon interface. In this work, we investigate the stability of said interface and we find that high temperature annealing leads to a loss of integrity. High–resolution transmission electron microscopy analysis shows a morphologically degraded SiC/Si interface, while mechanical stress measurements indicate considerable relaxation of the interfacial stress. From an electrical point of view, the diode behaviour of the initial p-Si/n-SiC junction is catastrophically lost due to considerable inter-diffusion of atoms and charges across the interface upon annealing. Temperature dependent transport measurements confirm a severe electrical shorting of the epitaxial silicon carbide to the underlying substrate, indicating vast predominance of the silicon carriers in lateral transport above 25 K. This finding has crucial consequences on the integration of epitaxial silicon carbide on silicon and its potential applications.

  2. High-resolution echocardiography

    Science.gov (United States)

    Nathan, R.

    1979-01-01

    High resolution computer aided ultrasound system provides two-and three-dimensional images of beating heart from many angles. System provides means for determining whether small blood vessels around the heart are blocked or if heart wall is moving normally without interference of dead and noncontracting muscle tissue.

  3. High resolution data acquisition

    Science.gov (United States)

    Thornton, G.W.; Fuller, K.R.

    1993-04-06

    A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock, pulse train, and analog circuitry for generating a triangular wave synchronously with the pulse train (as seen in diagram on patent). The triangular wave has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter counts the clock pulse train during the interval to form a gross event interval time. A computer then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

  4. High resolution (transformers.

    Science.gov (United States)

    Garcia-Souto, Jose A; Lamela-Rivera, Horacio

    2006-10-16

    A novel fiber-optic interferometric sensor is presented for vibrations measurements and analysis. In this approach, it is shown applied to the vibrations of electrical structures within power transformers. A main feature of the sensor is that an unambiguous optical phase measurement is performed using the direct detection of the interferometer output, without external modulation, for a more compact and stable implementation. High resolution of the interferometric measurement is obtained with this technique (transformers are also highlighted.

  5. High Resolution Spectral Analysis

    Science.gov (United States)

    2006-10-25

    liable methods for high resolution spectral analysis of multivariable processes, as well as to distance measures for quantitative assessment of...called "modern nonlinear spectral analysis methods " [27]. An alternative way to reconstruct /„(#), based on Tn, is the periodogram/correlogram f{6...eie). A homotopy method was proposed in [8, 9] leading to a differential equation for A(T) in a homotopy variable r. If the statistics are consistent

  6. Spatial resolution of wedge shaped silicon microstrip detectors

    Science.gov (United States)

    Antičić, T.; Barnett, B.; Blumenfeld, B.; Chien, C.-Y.; Fisher, P.; Gougas, A.; Krizmanic, J.; Madansky, L.; Newman, D.; Orndorff, J.; Pevsner, A.; Spangler, J.

    1995-02-01

    Several wedge-shaped silicon microstrip detectors with pitches from 30 to 100 μm have been designed by our group and beam tested at the CERN SPS. We find the spatial resolution σ becomes larger at the rate of 0.21 μm per 1 μm increase in pitch, but the number of strips per cluster remains about the same as the pitch varies from 30 to 100 μm.

  7. Spatial resolution of wedge shaped silicon microstrip detectors

    International Nuclear Information System (INIS)

    Anticic, T.; Barnett, B.; Blumenfeld, B.; Chien, C.Y.; Fisher, P.; Gougas, A.; Krizmanic, J.; Madansky, L.; Newman, D.; Orndorff, J.; Pevsner, A.; Spangler, J.

    1995-01-01

    Several wedge-shaped silicon microstrip detectors with pitches from 30 to 100 μm have been designed by our group and beam tested at the CERN SPS. We find the spatial resolution σ becomes larger at the rate of 0.21 μm per 1 μm increase in pitch, but the number of strips per cluster remains about the same as the pitch varies from 30 to 100 μm. (orig.)

  8. Improved spatial resolution of luminescence images acquired with a silicon line scanning camera

    Science.gov (United States)

    Teal, Anthony; Mitchell, Bernhard; Juhl, Mattias K.

    2018-04-01

    Luminescence imaging is currently being used to provide spatially resolved defect in high volume silicon solar cell production. One option to obtain the high throughput required for on the fly detection is the use a silicon line scan cameras. However, when using a silicon based camera, the spatial resolution is reduced as a result of the weakly absorbed light scattering within the camera's chip. This paper address this issue by applying deconvolution from a measured point spread function. This paper extends the methods for determining the point spread function of a silicon area camera to a line scan camera with charge transfer. The improvement in resolution is quantified in the Fourier domain and in spatial domain on an image of a multicrystalline silicon brick. It is found that light spreading beyond the active sensor area is significant in line scan sensors, but can be corrected for through normalization of the point spread function. The application of this method improves the raw data, allowing effective detection of the spatial resolution of defects in manufacturing.

  9. High resolution backscattering instruments

    International Nuclear Information System (INIS)

    Coldea, R.

    2001-01-01

    The principle of operation of indirect-geometry time-of-flight spectrometers are presented, including the IRIS at the ISIS spallation neutron source. The key features that make those types of spectrometers ideally suited for low-energy spectroscopy are: high energy resolution over a wide dynamic range, and simultaneous measurement over a large momentum transfer range provided by the wide angular detector coverage. To exemplify these features are discussed of single-crystal experiments of the spin dynamics in the two-dimensional frustrated quantum magnet Cs 2 CuCl 4 . (R.P.)

  10. High purity silane and silicon production

    Science.gov (United States)

    Breneman, William C. (Inventor)

    1987-01-01

    Silicon tetrachloride, hydrogen and metallurgical silicon are reacted at about 400.degree.-600.degree. C. and at pressures in excess of 100 psi, and specifically from about 300 up to about 600 psi to form di- and trichlorosilane that is subjected to disproportionation in the presence of an anion exchange resin to form high purity silane. By-product and unreacted materials are recycled, with metallurgical silicon and hydrogen being essentially the only consumed feed materials. The silane product may be further purified, as by means of activated carbon or cryogenic distillation, and decomposed in a fluid bed or free space reactor to form high purity polycrystalline silicon and by-product hydrogen which can be recycled for further use. The process results in simplified waste disposal operations and enhances the overall conversion of metallurgical grade silicon to silane and high purity silicon for solar cell and semiconductor silicon applications.

  11. Ultra-high-speed Optical Signal Processing using Silicon Photonics

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Ji, Hua; Jensen, Asger Sellerup

    with a photonic layer on top to interconnect them. For such systems, silicon is an attractive candidate enabling both electronic and photonic control. For some network scenarios, it may be beneficial to use optical on-chip packet switching, and for high data-density environments one may take advantage...... of the ultra-fast nonlinear response of silicon photonic waveguides. These chips offer ultra-broadband wavelength operation, ultra-high timing resolution and ultra-fast response, and when used appropriately offer energy-efficient switching. In this presentation we review some all-optical functionalities based...... on silicon photonics. In particular we use nano-engineered silicon waveguides (nanowires) [1] enabling efficient phasematched four-wave mixing (FWM), cross-phase modulation (XPM) or self-phase modulation (SPM) for ultra-high-speed optical signal processing of ultra-high bit rate serial data signals. We show...

  12. Limitations on energy resolution of segmented silicon detectors

    Science.gov (United States)

    Wiącek, P.; Chudyba, M.; Fiutowski, T.; Dąbrowski, W.

    2018-04-01

    In the paper experimental study of charge division effects and energy resolution of X-ray silicon pad detectors are presented. The measurements of electrical parameters, capacitances and leakage currents, for six different layouts of pad arrays are reported. The X-ray spectra have been measured using a custom developed dedicated low noise front-end electronics. The spectra measured for six different detector layouts have been analysed in detail with particular emphasis on quantitative evaluation of charge division effects. Main components of the energy resolution due to Fano fluctuations, electronic noise, and charge division, have been estimated for six different sensor layouts. General recommendations regarding optimisation of pad sensor layout for achieving best possible energy resolution have been formulated.

  13. High Time Resolution Astrophysics

    CERN Document Server

    Phelan, Don; Shearer, Andrew

    2008-01-01

    High Time Resolution Astrophysics (HTRA) is an important new window to the universe and a vital tool in understanding a range of phenomena from diverse objects and radiative processes. This importance is demonstrated in this volume with the description of a number of topics in astrophysics, including quantum optics, cataclysmic variables, pulsars, X-ray binaries and stellar pulsations to name a few. Underlining this science foundation, technological developments in both instrumentation and detectors are described. These instruments and detectors combined cover a wide range of timescales and can measure fluxes, spectra and polarisation. These advances make it possible for HTRA to make a big contribution to our understanding of the Universe in the next decade.

  14. High resolution ultrasonic densitometer

    International Nuclear Information System (INIS)

    Dress, W.B.

    1983-01-01

    The velocity of torsional stress pulses in an ultrasonic waveguide of non-circular cross section is affected by the temperature and density of the surrounding medium. Measurement of the transit times of acoustic echoes from the ends of a sensor section are interpreted as level, density, and temperature of the fluid environment surrounding that section. This paper examines methods of making these measurements to obtain high resolution, temperature-corrected absolute and relative density and level determinations of the fluid. Possible applications include on-line process monitoring, a hand-held density probe for battery charge state indication, and precise inventory control for such diverse fluids as uranium salt solutions in accountability storage and gasoline in service station storage tanks

  15. High resolution hadron calorimetry

    International Nuclear Information System (INIS)

    Wigmans, R.

    1987-01-01

    The components that contribute to the signal of a hadron calorimeter and the factors that affect its performance are discussed, concentrating on two aspects; energy resolution and signal linearity. Both are decisively dependent on the relative response to the electromagnetic and the non-electromagnetic shower components, the e/h signal ratio, which should be equal to 1.0 for optimal performance. The factors that determine the value of this ratio are examined. The calorimeter performance is crucially determined by its response to the abundantly present soft neutrons in the shower. The presence of a considerable fraction of hydrogen atoms in the active medium is essential for achieving the best possible results. Firstly, this allows one to tune e/h to the desired value by choosing the appropriate sampling fraction. And secondly, the efficient neutron detection via recoil protons in the readout medium itself reduces considerably the effect of fluctuations in binding energy losses at the nuclear level, which dominate the intrinsic energy resolution. Signal equalization, or compensation (e/h = 1.0) does not seem to be a property unique to 238 U, but can also be achieved with lead and probably even iron absorbers. 21 refs.; 19 figs

  16. Design of a charge sensitive preamplifier on high resistivity silicon

    International Nuclear Information System (INIS)

    Radeka, V.; Rehak, P.; Rescia, S.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Strueder, L.; Kemmer, J.

    1987-01-01

    A low noise, fast charge sensitive preamplifier was designed on high resistivity, detector grade silicon. It is built at the surface of a fully depleted region of n-type silicon. This allows the preamplifier to be placed very close to a detector anode. The preamplifier uses the classical input cascode configuration with a capacitor and a high value resistor in the feedback loop. The output stage of the preamplifier can drive a load up to 20pF. The power dissipation of the preamplifier is 13mW. The amplifying elements are ''Single Sided Gate JFETs'' developed especially for this application. Preamplifiers connected to a low capacitance anode of a drift type detector should achieve a rise time of 20ns and have an equivalent noise charge (ENC), after a suitable shaping, of less than 50 electrons. This performance translates to a position resolution better than 3μm for silicon drift detectors. 6 refs., 9 figs

  17. Spontaneous resolution of macular edema after silicone oil removal

    Directory of Open Access Journals (Sweden)

    Eyyup Karahan

    2014-12-01

    Full Text Available AIM:To investigate the macular changes in eyes filled with silicone oil (SO and course of these changes after SO removal.METHODS:A retrospective optical coherence tomography scan review was conducted for twenty-four patients who underwent uncomplicated pars plana vitrectomy with SO tamponade for complex retinal detachments were detected with optical coherence tomography before, and one week, one month and three months after SO removal.RESULTS:Mean duration of SO tamponade was 3.6±1.0mo (range:3-7mo. Cystoid macular edema (CME was detected in 3 eyes before SO removal. Submacular fluid was represented in 1 eye before silicone SO removal. Resolution of CME and submacular fluid was achieved 1mo after SO removal in all eyes. Mean best corrected visual acuity (BCVA was 1.15±0.65 (range, hand movement to 0.2 before SO removal in the eyes without macular changes. After SO removal, the mean BCVA values at 1wk and 1 and 3mo, and 0.82±0.23, 0.76±0.21, and 0.70±0.19, all of which were significantly better than baseline (P=0.030, 0.017, 0.006 respectively. In the eyes with macular CME and subretinal fluid the mean BCVA was significantly improved at 3mo after SO removal compared with baseline (P=0.037.CONCLUSION:Decreased visual acuity in eyes filled with SO could be caused by macular complications due to SO. CME and subretinal fluid may resolve without any additional macular surgery after SO removal.

  18. Handbook of High Resolution Spectroscopy

    OpenAIRE

    2011-01-01

    The field of High resolution Spectroscopy has been considerably extended and even redefined in some areas. Combining the knowledge of spectroscopy laser technology chemical computation and experiments Handbook of High resolution Spectroscopy provides a comprehensive survey of the whole field as it presents itself today with emphasis on the recent developments. This essential handbook for advanced research students graduate students and researchers takes a systematic approach through the rang...

  19. Enhanced High Resolution RBS System

    Science.gov (United States)

    Pollock, Thomas J.; Hass, James A.; Klody, George M.

    2011-06-01

    Improvements in full spectrum resolution with the second NEC high resolution RBS system are summarized. Results for 50 Å TiN/HfO films on Si yielding energy resolution on the order of 1 keV are also presented. Detector enhancements include improved pulse processing electronics, upgraded shielding for the MCP/RAE detector, and reduced noise generated from pumping. Energy resolution measurements on spectra front edge coupled with calculations using 0.4mStr solid angle show that beam energy spread at 400 KeV from the Pelletron® accelerator is less than 100 eV. To improve user throughput, magnet control has been added to the automatic data collection. Depth profiles derived from experimental data are discussed. For the thin films profiled, depth resolutions were on the Angstrom level with the non-linear energy/channel conversions ranging from 100 to 200 eV.

  20. High resolution digital delay timer

    Science.gov (United States)

    Martin, Albert D.

    1988-01-01

    Method and apparatus are provided for generating an output pulse following a trigger pulse at a time delay interval preset with a resolution which is high relative to a low resolution available from supplied clock pulses. A first lumped constant delay (20) provides a first output signal (24) at predetermined interpolation intervals corresponding to the desired high resolution time interval. Latching circuits (26, 28) latch the high resolution data (24) to form a first synchronizing data set (60). A selected time interval has been preset to internal counters (142, 146, 154) and corrected for circuit propagation delay times having the same order of magnitude as the desired high resolution. Internal system clock pulses (32, 34) count down the counters to generate an internal pulse delayed by an interval which is functionally related to the preset time interval. A second LCD (184) corrects the internal signal with the high resolution time delay. A second internal pulse is then applied to a third LCD (74) to generate a second set of synchronizing data (76) which is complementary with the first set of synchronizing data (60) for presentation to logic circuits (64). The logic circuits (64) further delay the internal output signal (72) to obtain a proper phase relationship of an output signal (80) with the internal pulses (32, 34). The final delayed output signal (80) thereafter enables the output pulse generator (82) to produce the desired output pulse (84) at the preset time delay interval following input of the trigger pulse (10, 12).

  1. Silicon/Porous Silicon Composite Membrane for High Sensitivity Pressure Sensor

    Science.gov (United States)

    2009-07-21

    for integrating with other processes on silicon wafer. The fabrication of silicone rubber membranes for making microvalves has been reported [5...alcohol (IPA) is used along with HF to increase the wettability of the silicon surface and to remove the bubbles formed during the reaction. Aluminium ...Report for AOARD funded Project No. AOARD-074061 Title: Silicon /Porous Silicon composite membrane for high sensitivity pressure sensor PI

  2. High-resolution plasma spectrometry

    International Nuclear Information System (INIS)

    Edelson, M.C.

    1987-01-01

    In this chapter, the authors consider the topic of high-resolution plasma spectrometry (HRPS). Several different experimental approaches to HRPS are reviewed, and the benefits derived from increased spectral resolution are discussed. Results from the scientific literature are presented, but no attempt is made to provide an encyclopedic review. The discussion is limited to plasma emission spectrometry and, in particular, to inductively coupled plasma-atomic emission spectrometry (ICP-AES)

  3. High resolution X ray spectroscopy

    International Nuclear Information System (INIS)

    Bartiromo, R.

    1987-01-01

    This paper is devoted to a detailed discussion of the physical processes which are responsible for the emission spectra of H-like and He-like ion of high Z impurities in low density plasmas. The application of high resolution X-ray spectroscopy to the diagnostic of tokamak plasmas is also discussed and examples of the results obtained are presented

  4. Berkeley High-Resolution Ball

    International Nuclear Information System (INIS)

    Diamond, R.M.

    1984-10-01

    Criteria for a high-resolution γ-ray system are discussed. Desirable properties are high resolution, good response function, and moderate solid angle so as to achieve not only double- but triple-coincidences with good statistics. The Berkeley High-Resolution Ball involved the first use of bismuth germanate (BGO) for anti-Compton shield for Ge detectors. The resulting compact shield permitted rather close packing of 21 detectors around a target. In addition, a small central BGO ball gives the total γ-ray energy and multiplicity, as well as the angular pattern of the γ rays. The 21-detector array is nearly complete, and the central ball has been designed, but not yet constructed. First results taken with 9 detector modules are shown for the nucleus 156 Er. The complex decay scheme indicates a transition from collective rotation (prolate shape) to single- particle states (possibly oblate) near spin 30 h, and has other interesting features

  5. Developments in high resolution radiography

    International Nuclear Information System (INIS)

    Ridder, H.J.

    1976-01-01

    Critical aspects in the design of metal-ceramic X-ray tubes for high resolution radiography are presented. The performance of an X-ray system in which the focalspot can be varied from 0.5mm to 0.05mm is discussed as well as number of studies, which includes an assessment of the value of electronic image enhancement

  6. Silicon Carbide Nanotube Oxidation at High Temperatures

    Science.gov (United States)

    Ahlborg, Nadia; Zhu, Dongming

    2012-01-01

    Silicon Carbide Nanotubes (SiCNTs) have high mechanical strength and also have many potential functional applications. In this study, SiCNTs were investigated for use in strengthening high temperature silicate and oxide materials for high performance ceramic nanocomposites and environmental barrier coating bond coats. The high · temperature oxidation behavior of the nanotubes was of particular interest. The SiCNTs were synthesized by a direct reactive conversion process of multiwall carbon nanotubes and silicon at high temperature. Thermogravimetric analysis (TGA) was used to study the oxidation kinetics of SiCNTs at temperatures ranging from 800degC to1300degC. The specific oxidation mechanisms were also investigated.

  7. High resolution tomographic instrument development

    International Nuclear Information System (INIS)

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational

  8. High resolution tomographic instrument development

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  9. High resolution tomographic instrument development

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  10. Section on High Resolution Optical Imaging (HROI)

    Data.gov (United States)

    Federal Laboratory Consortium — The Section on High Resolution Optical Imaging (HROI) develops novel technologies for studying biological processes at unprecedented speed and resolution. Research...

  11. High Resolution Orientation Distribution Function

    DEFF Research Database (Denmark)

    Schmidt, Søren; Gade-Nielsen, Nicolai Fog; Høstergaard, Martin

    2012-01-01

    A new method for reconstructing a High Resolution Orientation Distribution Function (HRODF) from X-ray diffraction data is presented. It is shown that the method is capable of accommodating very localized features, e.g. sharp peaks from recrystallized grains on a background of a texture component...... from the deformed material. The underlying mathematical formalism supports all crystallographic space groups and reduces the problem to solving a (large) set of linear equations. An implementation on multi-core CPUs and Graphical Processing Units (GPUs) is discussed along with an example on simulated...

  12. Self-Healing, High-Permittivity Silicone Dielectric Elastomer

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Skov, Anne Ladegaard

    2016-01-01

    possesses high dielectric permittivity and consists of an interpenetrating polymer network of silicone elastomer and ionic silicone species that are cross-linked through proton exchange between amines and acids. The ionically cross-linked silicone provides self-healing properties after electrical breakdown...

  13. High-Index Contrast Silicon Rich Silicon Nitride Optical Waveguides and Devices

    DEFF Research Database (Denmark)

    Philipp, Hugh Taylor

    2004-01-01

    This research focused on the realization of high-density integrated optical devices made with high-index contrast waveguides. The material platform used for to develop these devices was modeled after standard silicon on silicon technology. The high-index waveguide core material was silicon rich...... silicon nitride. This provided a sharp contrast with silica and made low-loss waveguide bending radii less than 25mm possible. An immediate consequence of such small bending radii is the ability to make practical ring resonator based devices with a large free spectral range. Several ring resonator based...

  14. High resolution, high speed ultrahigh vacuum microscopy

    International Nuclear Information System (INIS)

    Poppa, Helmut

    2004-01-01

    The history and future of transmission electron microscopy (TEM) is discussed as it refers to the eventual development of instruments and techniques applicable to the real time in situ investigation of surface processes with high resolution. To reach this objective, it was necessary to transform conventional high resolution instruments so that an ultrahigh vacuum (UHV) environment at the sample site was created, that access to the sample by various in situ sample modification procedures was provided, and that in situ sample exchanges with other integrated surface analytical systems became possible. Furthermore, high resolution image acquisition systems had to be developed to take advantage of the high speed imaging capabilities of projection imaging microscopes. These changes to conventional electron microscopy and its uses were slowly realized in a few international laboratories over a period of almost 40 years by a relatively small number of researchers crucially interested in advancing the state of the art of electron microscopy and its applications to diverse areas of interest; often concentrating on the nucleation, growth, and properties of thin films on well defined material surfaces. A part of this review is dedicated to the recognition of the major contributions to surface and thin film science by these pioneers. Finally, some of the important current developments in aberration corrected electron optics and eventual adaptations to in situ UHV microscopy are discussed. As a result of all the path breaking developments that have led to today's highly sophisticated UHV-TEM systems, integrated fundamental studies are now possible that combine many traditional surface science approaches. Combined investigations to date have involved in situ and ex situ surface microscopies such as scanning tunneling microscopy/atomic force microscopy, scanning Auger microscopy, and photoemission electron microscopy, and area-integrating techniques such as x-ray photoelectron

  15. Modelling magnetic properties of high silicon steel

    International Nuclear Information System (INIS)

    Chwastek, Krzysztof; SzczygLowski, Jan; Wilczynski, WiesLaw

    2010-01-01

    The paper is aimed at modelling dynamic hysteresis loops of high silicon steel. Hysteresis loops are described with the modified Jiles-Atherton approach. The dynamic effects due to eddy currents are taken into account by the introduction of components of effective field related to loss components in Bertotti's model. A satisfactory agreement between the measured and the modelled dynamic hysteresis loops as well as derived quantities is obtained for those values of peak flux density and frequency, which are of interest from industrial point of view.

  16. Modelling magnetic properties of high silicon steel

    Science.gov (United States)

    Chwastek, Krzysztof; SzczygŁowski, Jan; Wilczyński, WiesŁaw

    2010-04-01

    The paper is aimed at modelling dynamic hysteresis loops of high silicon steel. Hysteresis loops are described with the modified Jiles-Atherton approach. The dynamic effects due to eddy currents are taken into account by the introduction of components of effective field related to loss components in Bertotti's model. A satisfactory agreement between the measured and the modelled dynamic hysteresis loops as well as derived quantities is obtained for those values of peak flux density and frequency, which are of interest from industrial point of view.

  17. Modelling magnetic properties of high silicon steel

    Energy Technology Data Exchange (ETDEWEB)

    Chwastek, Krzysztof, E-mail: krzysztof.chwastek@gmail.co [Faculty of Electrical Engineering, Al. Armii Krajowej 17, 42-200 Czestochowa (Poland); SzczygLowski, Jan [Faculty of Electrical Engineering, Al. Armii Krajowej 17, 42-200 Czestochowa (Poland); Wilczynski, WiesLaw [Institute of Electrical Engineering, ul. Pozaryskiego 28, 04-703 Warszawa (Poland)

    2010-04-15

    The paper is aimed at modelling dynamic hysteresis loops of high silicon steel. Hysteresis loops are described with the modified Jiles-Atherton approach. The dynamic effects due to eddy currents are taken into account by the introduction of components of effective field related to loss components in Bertotti's model. A satisfactory agreement between the measured and the modelled dynamic hysteresis loops as well as derived quantities is obtained for those values of peak flux density and frequency, which are of interest from industrial point of view.

  18. High-resolution ultrasonic spectroscopy

    Directory of Open Access Journals (Sweden)

    V. Buckin

    2018-03-01

    Full Text Available High-resolution ultrasonic spectroscopy (HR-US is an analytical technique for direct and non-destructive monitoring of molecular and micro-structural transformations in liquids and semi-solid materials. It is based on precision measurements of ultrasonic velocity and attenuation in analysed samples. The application areas of HR-US in research, product development, and quality and process control include analysis of conformational transitions of polymers, ligand binding, molecular self-assembly and aggregation, crystallisation, gelation, characterisation of phase transitions and phase diagrams, and monitoring of chemical and biochemical reactions. The technique does not require optical markers or optical transparency. The HR-US measurements can be performed in small sample volumes (down to droplet size, over broad temperature range, at ambient and elevated pressures, and in various measuring regimes such as automatic temperature ramps, titrations and measurements in flow.

  19. High resolution digital radiography system

    International Nuclear Information System (INIS)

    Stein, J.

    1983-01-01

    A digital radiography system includes an x-ray source for projecting a beam of x-rays toward and through an object to be examined onto the input face of an image intensifier tube. A multi-hole collimator is disposed between the object and the image intensifier tube for producing a two-dimensional array of spaced pencil beams, and these pencil beams are raster scanned relative to the object being examined and across the input face of the image intensifier tube through small distances corresponding generally to the distance between the holes in the collimator. The succession of images which are produced on the output face of the image intensifier tube during the scanning of the pencil beams are scanned by a video camera whose output signals are digitized and stored as partial images, and the partial images are thereafter interleaved with one another to provide a composite comparatively high resolution image of the object being examined

  20. Analysis of single-photon time resolution of FBK silicon photomultipliers

    International Nuclear Information System (INIS)

    Acerbi, Fabio; Ferri, Alessandro; Gola, Alberto; Zorzi, Nicola; Piemonte, Claudio

    2015-01-01

    We characterized and analyzed an important feature of silicon photomultipliers: the single-photon time resolution (SPTR). We characterized the SPTR of new RGB (Red–Green–Blue) type Silicon Photomultipliers and SPADs produced at FBK (Trento, Italy), studying its main limiting factors. We compared time resolution of 1×1 mm 2 and 3×3 mm 2 SiPMs and a single SiPM cell (i.e. a SPAD with integrated passive-quenching), employing a mode-locked pulsed laser with 2-ps wide pulses. We estimated the contribution of front-end electronic-noise, of cell-to-cell uniformity, and intrinsic cell time-resolution. At a single-cell level, we compared the results obtained with different layouts. With a circular cell with a top metallization covering part of the edge and enhancing the signal extraction, we reached ~20 ps FWHM of time resolution

  1. Analysis of single-photon time resolution of FBK silicon photomultipliers

    Energy Technology Data Exchange (ETDEWEB)

    Acerbi, Fabio, E-mail: acerbi@fbk.eu; Ferri, Alessandro; Gola, Alberto; Zorzi, Nicola; Piemonte, Claudio

    2015-07-01

    We characterized and analyzed an important feature of silicon photomultipliers: the single-photon time resolution (SPTR). We characterized the SPTR of new RGB (Red–Green–Blue) type Silicon Photomultipliers and SPADs produced at FBK (Trento, Italy), studying its main limiting factors. We compared time resolution of 1×1 mm{sup 2} and 3×3 mm{sup 2} SiPMs and a single SiPM cell (i.e. a SPAD with integrated passive-quenching), employing a mode-locked pulsed laser with 2-ps wide pulses. We estimated the contribution of front-end electronic-noise, of cell-to-cell uniformity, and intrinsic cell time-resolution. At a single-cell level, we compared the results obtained with different layouts. With a circular cell with a top metallization covering part of the edge and enhancing the signal extraction, we reached ~20 ps FWHM of time resolution.

  2. Energy and spatial resolution of a Shashlik calorimeter and a silicon preshower detector

    Energy Technology Data Exchange (ETDEWEB)

    Aspell, P.; Bates, S.; Bloch, P. [European Lab. for Particle Phys. (CERN), Geneva (Switzerland)] [and others; Grabit, R.; Jarron, P.; Kloukinas, K.; Lemeilleur, F.; Loos, R.; Marchioro, A.; Rosso, E.; Badier, J.; Bourotte, J.; Busata, A.; Busson, Ph.; Charlot, C.; Dobrzynski, L.; Ferreira, O.; Gregory, C.; Karar, A.; Manigot, P.; Tanaka, R.; Vanel, J.C.; Bityukov, S.; Obraztsov, V.; Ostankov, A.; Protopopov, Yu.; Rykalin, V.; Spiridonov, P.; Soushkov, V.; Vasil`chenko, V.; Clayton, E.; Miller, D.; Seez, C.; Virdee, T.S.; Djilkibaev, R.; Gninenko, S.; Guschin, E.; Musienko, Y.; Popov, V.; Skasyrskaya, A.; Semenyuk, I.; Cheremukhin, I.; Egorov, A.; Golutvin, I.; Kozlov, Y.; Moissenz, P.; Sergueev, S.; Sidorov, A.; Zubarev, E.; Zamiatin, N.; Bordalo, P.; Ramos, S.; Varela, J.; Cockerill, D.J.A.; Connolly, J.; Denton, L.; Godinovic, N.; Puljak, I.; Soric, I.; Chendvankar, S.R.; Gupta, S.K.; Ganguli, S.N.; Gurtu, A.; Maity, M.; Majumder, G.; Mazumdar, K.; Moulik, T. [European Laboratory for Particle Physics (CERN), 1211 Geneva 23 (Switzerland)]|[LPNHE, Ecole Polytechnique, IN2P3-CNRS, 91128 Palaiseau Cedex (France)]|[Institute for High Energy Physics, Serpukhov, 142 284 Protvino, Moscow (Russian Federation)]|[Department of Physics, Imperial College, London SW7 2BZ (United Kingdom)]|[Institute for Nuclear Research, Russian Academy of Science, Troitsk (Russian Federation)]|[Joint Institute for Nuclear Research, 141 980 Dubna, Moscow (Russian Federation)]|[LIP, Av. Elias Garcia 14-1, 1000 Lisboa Codex (Portugal)]|[Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom)]|[FESB, University of Split, R. Boskovica bb, 21 000 Split (Croatia)]|[EHEP Group, Tata Institute of Fundamental Research, Colaba, Bombay 400 005 (India); RD36 Collaboration

    1996-06-21

    New projective prototypes of a scintillator/lead sandwich type sampling calorimeter Shashlik with a silicon preshower detector have been constructed and tested with an electron beam at CERN-SPS. The energy resolution is measured to be 8.7%/{radical}(E(GeV)) in stochastic term, 0.330/E(GeV) in noise term and 0.5% in constant term. The angular resolution is better than 70 mrad/{radical}(E(GeV)). (orig.).

  3. Factors affecting the energy resolution in alpha particle spectrometry with silicon diodes

    International Nuclear Information System (INIS)

    Camargo, Fabio de.

    2005-01-01

    In this work are presented the studies about the response of a multi-structure guard rings silicon diode for detection and spectrometry of alpha particles. This ion-implanted diode (Al/p + /n/n + /Al) was processed out of 300 μm thick, n type substrate with a resistivity of 3 kΩ·cm and an active area of 4 mm 2 . In order to use this diode as a detector, the bias voltage was applied on the n + side, the first guard ring was grounded and the electrical signals were readout from the p + side. These signals were directly sent to a tailor made preamplifier, based on the hybrid circuit A250 (Amptek), followed by a conventional nuclear electronic. The results obtained with this system for the direct detection of alpha particles from 241 Am showed an excellent response stability with a high detection efficiency (≅ 100 %). The performance of this diode for alpha particle spectrometry was studied and it was prioritized the influence of the polarization voltage, the electronic noise, the temperature and the source-diode distance on the energy resolution. The results showed that the major contribution for the deterioration of this parameter is due to the diode dead layer thickness (1 μm). However, even at room temperature, the energy resolution (FWHM = 18.8 keV) measured for the 5485.6 MeV alpha particles ( 241 Am) is comparable to those obtained with ordinary silicon barrier detectors frequently used for these particles spectrometry. (author)

  4. Electrochemical Deposition of High Purity Silicon from Molten Salts

    Science.gov (United States)

    Haarberg, Geir Martin

    Several approaches were tried in order to develop an electrochemical route for producing high purity silicon from molten salts. SiO2, K2SiF6 and metallurgical silicon were used as the source of silicon. Molten electrolytes based on chloride (CaCl2-NaCl) and fluoride (LiF-KF) at temperatures from 550 - 900 oC were used. Transient electrochemical techniques were used to study the electrochemical behaviour of dissolved silicon species. Electrolysis experiments were carried out to deposit silicon.

  5. Electrochemical Deposition of High Purity Silicon in Molten Salts

    Science.gov (United States)

    Haarberg, Geir Martin

    Several approaches were tried in order to develop an electrochemical route for producing high purity silicon from molten salts. SiO2, K2SiF6 and metallurgical silicon were used as the source of silicon. Molten electrolytes based on chloride (CaCl2-NaCl) and fluoride (LiF-KF) at temperatures from 550 - 900 °C were used. Transient electrochemical techniques were used to study the electrochemical behaviour of dissolved silicon species. Electrolysis experiments were carried out to deposit silicon.

  6. High spatial resolution probes for neurobiology applications

    Science.gov (United States)

    Gunning, D. E.; Kenney, C. J.; Litke, A. M.; Mathieson, K.

    2009-06-01

    Position-sensitive biological neural networks, such as the brain and the retina, require position-sensitive detection methods to identify, map and study their behavior. Traditionally, planar microelectrodes have been employed to record the cell's electrical activity with device limitations arising from the electrode's 2-D nature. Described here is the development and characterization of an array of electrically conductive micro-needles aimed at addressing the limitations of planar electrodes. The capability of this array to penetrate neural tissue improves the electrode-cell electrical interface and allows more complicated 3-D networks of neurons, such as those found in brain slices, to be studied. State-of-the-art semiconductor fabrication techniques were used to etch and passivate conformally the metal coat and fill high aspect ratio holes in silicon. These are subsequently transformed into needles with conductive tips. This process has enabled the fabrication of arrays of unprecedented dimensions: 61 hexagonally close-packed electrodes, ˜200 μm tall with 60 μm spacing. Electroplating the tungsten tips with platinum ensure suitable impedance values (˜600 kΩ at 1 kHz) for the recording of neuronal signals. Without compromising spatial resolution of the neuronal recordings, this array adds a new and exciting dimension to the study of biological neural networks.

  7. High resolution emission tomography; Tomographie d`emission haute resolution

    Energy Technology Data Exchange (ETDEWEB)

    Charon, Y.; Laniece, P.; Mastrippolito, R.; Pinot, L.; Ploux, L.; Valda Ochoa, A.; Valentin, L. [Groupe I.P.B., Experimental Research Division, Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1999-11-01

    We have developed an original high resolution tomograph for in-vivo small animal imaging. A first prototype is under evaluation. Initial results of its characterisation are presented. (authors) 3 figs.

  8. Evaluation of Advanced Bionics high resolution mode.

    Science.gov (United States)

    Buechner, Andreas; Frohne-Buechner, Carolin; Gaertner, Lutz; Lesinski-Schiedat, Anke; Battmer, Rolf-Dieter; Lenarz, Thomas

    2006-07-01

    The objective of this paper is to evaluate the advantages of the Advanced Bionic high resolution mode for speech perception, through a retrospective analysis. Forty-five adult subjects were selected who had a minimum experience of three months' standard mode (mean of 10 months) before switching to high resolution mode. Speech perception was tested in standard mode immediately before fitting with high resolution mode, and again after a maximum of six months high resolution mode usage (mean of two months). A significant improvement was found, between 11 and 17%, depending on the test material. The standard mode preference does not give any indication about the improvement when switching to high resolution. Users who are converted within any study achieve a higher performance improvement than those converted in the clinical routine. This analysis proves the significant benefits of high resolution mode for users, and also indicates the need for guidelines for individual optimization of parameter settings in a high resolution mode program.

  9. VT Hydrography Dataset - High Resolution NHD

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The Vermont Hydrography Dataset (VHD) is compliant with the local resolution (also known as High Resolution) National Hydrography Dataset (NHD)...

  10. High Resolution TPM Cosmological Simulations

    Science.gov (United States)

    Xu, Guohong

    1995-01-01

    Cosmological simulation of galaxy formation is a grand challenge problem for both astrophysicists and numerical methodologists. The large dynamic range required to simulate structure formation properly stimulates a search for fast and accurate algorithm which can be fitted into the the front end massively parallel computers. In this thesis, we present our efforts to approach this problem. We proposed and implemented a novel algorithm TPM to perform large cosmological N-body simulations on parallel machines. The TPM method combines the advantages of the fast Particle-Mesh (PM) method and the accurate TREE method. We classify the particles in the simulation box to be PM particles and TREE particles according to their local density. Since structure forms at high density regions, we apply the accurate TREE method to the particles in these regions. The fact that the gravity equation is linear allows us to linearly combine the forces calculated using different methods. Individual objects interact with each other through tidal force, which changes slower than the internal evolution of an object. Thus we can allow individual time steps for each object, which is represented by a group of particles in the same TREE. We parallelize the method by throw each processor a different TREE to process, and several processors can collaborate with each other to evolve the same TREE when necessary. This mechanism gives the code high efficiency on massively parallel computers. With the TPM code, we can easily perform N = 128^ {3} particle simulations with high force resolution (~1/7680 of box size). We have also performed simulations with N = 256^3 particles with the best dynamic range achieved in this field. We put special attention when selecting the parameters of the cosmological models in our simulations. The COBE normalization is taken as a standard to normalize the initial condition, while the results from large scale sky surveys are also taken into consideration. In this thesis we

  11. Micro-machined high capacity silicon load cells

    NARCIS (Netherlands)

    Zwijze, A.F.

    2000-01-01

    The aim of the research presented in this thesis is to improve the performance of high capacity conventional load cells or force sensors by using silicon as the base material. Silicon is used because it offers the possibility of realising small, light, low cost and high performance mechanical

  12. 3D detectors with high space and time resolution

    Science.gov (United States)

    Loi, A.

    2018-01-01

    For future high luminosity LHC experiments it will be important to develop new detector systems with increased space and time resolution and also better radiation hardness in order to operate in high luminosity environment. A possible technology which could give such performances is 3D silicon detectors. This work explores the possibility of a pixel geometry by designing and simulating different solutions, using Sentaurus Tecnology Computer Aided Design (TCAD) as design and simulation tool, and analysing their performances. A key factor during the selection was the generated electric field and the carrier velocity inside the active area of the pixel.

  13. Development of Silicon Detectors for the High Luminosity LHC

    International Nuclear Information System (INIS)

    Eichhorn, Thomas Valentin

    2015-07-01

    The Large Hadron Collider (LHC) at CERN will be upgraded to a High Luminosity LHC in the year 2022, increasing the instantaneous luminosity by a factor of five. This will have major impacts on the experiments at the LHC, such as the Compact Muon Solenoid (CMS) experiment, and especially for their inner silicon tracking systems. Among other things, the silicon sensors used therein will be exposed to unprecedented levels of radiation damage, necessitating a replacement of the entire tracking detector. In order to maintain the excellent current performance, a new tracking detector has to be equipped with sensors of increased radiation hardness and higher granularity. The CMS experiment is undertaking an extensive R and D campaign in the search for the future silicon sensor technology baseline to be used in this upgrade. This thesis presents two methods suitable for use in this search: finite element TCAD simulations and test beam measurements. The simulations are focussed on the interstrip capacitance between sensor strips and are compared to measurements before and after the inclusion of radiation damage effects. A geometrical representation of the strip sensors used in the campaign has been found, establishing the predictive power of simulations. The test beam measurements make use of the high-precision pixel telescopes available at the DESY-II test beam facility. The performance of these telescopes has been assessed and their achievable pointing resolution has been found to be below 2 μm. Thin, epitaxial silicon is a candidate material for usage in radiation hard sensors for the future CMS tracking detector. Sample strip sensors of this material have been irradiated to fluences of up to 1.3 x 10 16 n eq /cm 2 with 800 MeV or 23 GeV protons. Test beam measurements with 5 GeV electrons have been performed to investigate the radiation hardness of epitaxial sensors using the pixel beam telescopes. The epitaxial device under test (DUT) has been integrated into the

  14. Measurements of timing resolution of ultra-fast silicon detectors with the SAMPIC WTDC

    CERN Document Server

    Breton, Dominique

    2016-11-01

    The SAMpler for PICosecond time (SAMPIC) chip has been designed by a collaboration including CEA/IRFU/SEDI, Saclay and CNRS/LAL/SERDI, Orsay. It benefits from both the quick response of a time to digital converter (TDC) and the versatility of a waveform digitizer to perform accurate timing measurements. Thanks to the sampled signals, smart algorithms making best use of the pulse shape can be used to maximize time resolution. A software framework has been developed to analyse the SAMPIC output data and extract timing information by using either a constant fraction discriminator or a fast cross-correlation algorithm. SAMPIC timing capabilities together with the software framework have been tested using Gaussian signals generated by a signal generator or by silicon detectors pulsed with an infra-red laser. Under these ideal experimental conditions, the SAMPIC chip has proven to be capable of timing resolutions down to 4 (40) ps with synthesized (silicon detector) signals.

  15. High-resolution electron microscopy

    CERN Document Server

    Spence, John C H

    2013-01-01

    This new fourth edition of the standard text on atomic-resolution transmission electron microscopy (TEM) retains previous material on the fundamentals of electron optics and aberration correction, linear imaging theory (including wave aberrations to fifth order) with partial coherence, and multiple-scattering theory. Also preserved are updated earlier sections on practical methods, with detailed step-by-step accounts of the procedures needed to obtain the highest quality images of atoms and molecules using a modern TEM or STEM electron microscope. Applications sections have been updated - these include the semiconductor industry, superconductor research, solid state chemistry and nanoscience, and metallurgy, mineralogy, condensed matter physics, materials science and material on cryo-electron microscopy for structural biology. New or expanded sections have been added on electron holography, aberration correction, field-emission guns, imaging filters, super-resolution methods, Ptychography, Ronchigrams, tomogr...

  16. Low cost routes to high purity silicon and derivatives thereof

    Science.gov (United States)

    Laine, Richard M; Krug, David James; Marchal, Julien Claudius; Mccolm, Andrew Stewart

    2013-07-02

    The present invention is directed to a method for providing an agricultural waste product having amorphous silica, carbon, and impurities; extracting from the agricultural waste product an amount of the impurities; changing the ratio of carbon to silica; and reducing the silica to a high purity silicon (e.g., to photovoltaic silicon).

  17. Production of nano structured silicon carbide by high energy ball ...

    African Journals Online (AJOL)

    In this paper, an attempt has been made to modify the micro sized Silicon carbide powder into nano structured Silicon carbide powder using High Energy Ball Mill. Ball milling was carried out for the total duration of 50 hours. The sample was taken out after every 5 hours of milling and it was characterized for its crystallite ...

  18. Intraocular inflammation following endotamponade with high-density silicone oil.

    NARCIS (Netherlands)

    Theelen, T.; Tilanus, M.A.D.; Klevering, B.J.

    2004-01-01

    BACKGROUND: The use of a mixture of silicone oil and partially fluorinated alkanes (high-density silicone oil) has recently been suggested as intraocular tamponade in complicated retinal detachment of the inferior quadrants. We describe a series of patients who developed a clinical picture

  19. Hydrophilic functionalized silicon nanoparticles produced by high energy ball milling

    Science.gov (United States)

    Hallmann, Steffen

    The mechanochemical synthesis of functionalized silicon nanoparticles using High Energy Ball Milling (HEBM) is described. This method facilitates the fragmentation of mono crystalline silicon into the nanometer regime and the simultaneous surface functionalization of the formed particles. The surface functionalization is induced by the reaction of an organic liquid, such as alkynes and alkenes with reactive silicon sites. This method can be applied to form water soluble silicon nanoparticles by lipid mediated micelle formation and the milling in organic liquids containing molecules with bi-functional groups, such as allyl alcohol. Furthermore, nanometer sized, chloroalkyl functionalized particles can be synthesized by milling the silicon precursor in the presence of an o-chloroalkyne with either alkenes or alkynes as coreactants. This process allows tuning of the concentration of the exposed, alkyl linked chloro groups, simply by varying the relative amounts of the coreactant. The silicon nanoparticles that are formed serve as the starting point for a wide variety of chemical reactions, which may be used to alter the surface properties of the functionalized nanoparticles. Finally, the use of functionalized silicon particles for the production of superhydrophobic films is described. Here HEBM proves to be an efficient method to produce functionalized silicon particles, which can be deposited to form a stable coating exhibiting superhydrophobic properties. The hydrophobicity of the silicon film can be tuned by the milling time and thus the resulting surface roughness of the films.

  20. High resolution scintillation detector with semiconductor readout

    Science.gov (United States)

    Levin, Craig S.; Hoffman, Edward J.

    2000-01-01

    A novel high resolution scintillation detector array for use in radiation imaging such as high resolution Positron Emission Tomography (PET) which comprises one or more parallelepiped crystals with at least one long surface of each crystal being in intimate contact with a semiconductor photodetector such that photons generated within each crystal by gamma radiation passing therethrough is detected by the photodetector paired therewith.

  1. High-resolution lattice-spacing comparator using SR

    International Nuclear Information System (INIS)

    Zhang, Xiaowei; Sugiyama, Hiroshi; Ando, Masami

    2004-01-01

    A novel lattice spacing measurement using a high-resolution self-reference d-spacing comparator has been described. Self selection of monochromatic synchrotron x-rays by a monolithic double channel-cut-crystal monochromator (MDCM) comprising silicon 2,6,4 and 6,2,4 reflections may lead to a stable, highly-collimated and narrow bandwidth beam. Also if utilizing 2,6,4 and 6,2,4 Bragg planes of a silicon sample, the interval between two associated Bragg peaks for the X-rays with wavelength of 0.13438 nm can be extremely small, so that the diffraction angle can be determined with high precision and the traveling time from one peak to the other can be marvelously reduced by the order of at least three compared to the established classical methods such as the Bond method. Thus this so-called self-reference comparator method can dramatically save measurement time and provide an absolute measurement on the basis of the x-ray wavelength of the MDCM, therefore a lattice spacing measurement with uncertainty of 10 -8 , for the 1mm 2 area on a silicon crystal within measurement time of a few ten seconds and has been achieved. (author)

  2. Silicon dioxide with a silicon interfacial layer as an insulating gate for highly stable indium phosphide metal-insulator-semiconductor field effect transistors

    Science.gov (United States)

    Kapoor, V. J.; Shokrani, M.

    1991-01-01

    A novel gate insulator consisting of silicon dioxide (SiO2) with a thin silicon (Si) interfacial layer has been investigated for high-power microwave indium phosphide (InP) metal-insulator-semiconductor field effect transistors (MISFETs). The role of the silicon interfacial layer on the chemical nature of the SiO2/Si/InP interface was studied by high-resolution X-ray photoelectron spectroscopy. The results indicated that the silicon interfacial layer reacted with the native oxide at the InP surface, thus producing silicon dioxide, while reducing the native oxide which has been shown to be responsible for the instabilities in InP MISFETs. While a 1.2-V hysteresis was present in the capacitance-voltage (C-V) curve of the MIS capacitors with silicon dioxide, less than 0.1 V hysteresis was observed in the C-V curve of the capacitors with the silicon interfacial layer incorporated in the insulator. InP MISFETs fabricated with the silicon dioxide in combination with the silicon interfacial layer exhibited excellent stability with drain current drift of less than 3 percent in 10,000 sec, as compared to 15-18 percent drift in 10,000 sec for devices without the silicon interfacial layer. High-power microwave InP MISFETs with Si/SiO2 gate insulators resulted in an output power density of 1.75 W/mm gate width at 9.7 GHz, with an associated power gain of 2.5 dB and 24 percent power added efficiency.

  3. Reaching 200-ps timing resolution in a time-of-flight and depth-of-interaction positron emission tomography detector using phosphor-coated crystals and high-density silicon photomultipliers

    Science.gov (United States)

    Kwon, Sun Il; Ferri, Alessandro; Gola, Alberto; Berg, Eric; Piemonte, Claudio; Cherry, Simon R.; Roncali, Emilie

    2016-01-01

    Abstract. Current research in the field of positron emission tomography (PET) focuses on improving the sensitivity of the scanner with thicker detectors, extended axial field-of-view, and time-of-flight (TOF) capability. These create the need for depth-of-interaction (DOI) encoding to correct parallax errors. We have proposed a method to encode DOI using phosphor-coated crystals. Our initial work using photomultiplier tubes (PMTs) demonstrated the possibilities of the proposed method, however, a major limitation of PMTs for this application is poor quantum efficiency in yellow light, corresponding to the wavelengths of the converted light by the phosphor coating. In contrast, the red-green-blue-high-density (RGB-HD) silicon photomultipliers (SiPMs) have a high photon detection efficiency across the visible spectrum. Excellent coincidence resolving time (CRT; <210  ps) was obtained by coupling RGB-HD SiPMs and  3 × 3 × 20  mm3 lutetium fine silicate crystals coated on a third of one of their lateral sides. Events were classified in three DOI bins (∼6.7-mm width) with an average sensitivity of 83.1%. A CRT of ∼200  ps combined with robust DOI encoding is a marked improvement in the phosphor-coated approach that we pioneered. For the first time, we read out these crystals with SiPMs and clearly demonstrated the potential of the RGB-HD SiPMs for this TOF-DOI PET detector. PMID:27921069

  4. High-Resolution Data for a Low-Resolution World

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Brendan Williams [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-10

    In the past 15 years, the upper section of Cañon de Valle has been severely altered by wildfires and subsequent runoff events. Loss of root structures on high-angle slopes results in debris flow and sediment accumulation in the narrow canyon bottom. The original intent of the study described here was to better understand the changes occurring in watershed soil elevations over the course of several post-fire years. An elevation dataset from 5 years post-Cerro Grande fire was compared to high-resolution LiDAR data from 14 years post-Cerro Grande fire (also 3 years post-Las Conchas fire). The following analysis was motivated by a problematic comparison of these datasets of unlike resolution, and therefore focuses on what the data reveals of itself. The objective of this study is to highlight the effects vegetation can have on remote sensing data that intends to read ground surface elevation.

  5. Silicon Photomultiplier Performance in High ELectric Field

    Science.gov (United States)

    Montoya, J.; Morad, J.

    2016-12-01

    Roughly 27% of the universe is thought to be composed of dark matter. The Large Underground Xenon (LUX) relies on the emission of light from xenon atoms after a collision with a dark matter particle. After a particle interaction in the detector, two things can happen: the xenon will emit light and charge. The charge (electrons), in the liquid xenon needs to be pulled into the gas section so that it can interact with gas and emit light. This allows LUX to convert a single electron into many photons. This is done by applying a high voltage across the liquid and gas regions, effectively ripping electrons out of the liquid xenon and into the gas. The current device used to detect photons is the photomultiplier tube (PMT). These devices are large and costly. In recent years, a new technology that is capable of detecting single photons has emerged, the silicon photomultiplier (SiPM). These devices are cheaper and smaller than PMTs. Their performance in a high electric fields, such as those found in LUX, are unknown. It is possible that a large electric field could introduce noise on the SiPM signal, drowning the single photon detection capability. My hypothesis is that SiPMs will not observe a significant increase is noise at an electric field of roughly 10kV/cm (an electric field within the range used in detectors like LUX). I plan to test this hypothesis by first rotating the SiPMs with no applied electric field between two metal plates roughly 2 cm apart, providing a control data set. Then using the same angles test the dark counts with the constant electric field applied. Possibly the most important aspect of LUX, is the photon detector because it's what detects the signals. Dark matter is detected in the experiment by looking at the ratio of photons to electrons emitted for a given interaction in the detector. Interactions with a low electron to photon ratio are more like to be dark matter events than those with a high electron to photon ratio. The ability to

  6. High Resolution Bathymetry Estimation Improvement with Single Image Super-Resolution Algorithm Super-Resolution Forests

    Science.gov (United States)

    2017-01-26

    Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/5514--17-9692 High Resolution Bathymetry Estimation Improvement with Single Image Super... Single Image Super-Resolution Algorithm “Super-Resolution Forests” Dylan Einsidler,* Kristen Nock, Leslie Smith, David Bonanno, Paul Elmore, Warren Wood...release; distribution is unlimited. *Florida Atlantic University, 777 Glades Rd., Boca Raton, FL 33431 11 Leslie N. Smith (202) 767-9532 Using the single

  7. Iron solubility in highly boron-doped silicon

    International Nuclear Information System (INIS)

    McHugo, S.A.; McDonald, R.J.; Smith, A.R.; Hurley, D.L.; Weber, E.R.

    1998-01-01

    We have directly measured the solubility of iron in high and low boron-doped silicon using instrumental neutron activation analysis. Iron solubilities were measured at 800, 900, 1000, and 1100thinsp degree C in silicon doped with either 1.5x10 19 or 6.5x10 14 thinspboronthinspatoms/cm 3 . We have measured a greater iron solubility in high boron-doped silicon as compared to low boron-doped silicon, however, the degree of enhancement is lower than anticipated at temperatures >800thinsp degree C. The decreased enhancement is explained by a shift in the iron donor energy level towards the valence band at elevated temperatures. Based on this data, we have calculated the position of the iron donor level in the silicon band gap at elevated temperatures. We incorporate the iron energy level shift in calculations of iron solubility in silicon over a wide range of temperatures and boron-doping levels, providing a means to accurately predict iron segregation between high and low boron-doped silicon. copyright 1998 American Institute of Physics

  8. Macroporous silicon for high-capacitance devices using metal electrodes.

    Science.gov (United States)

    Vega, Didac; Reina, Jordi; Martí, Ferran; Pavón, Ramón; Rodríguez, Angel

    2014-01-01

    In this paper, high-capacity energy storage devices based on macroporous silicon are demonstrated. Small footprint devices with large specific capacitances up to 100 nF/mm(2), and an absolute capacitance above 15 μF, have been successfully fabricated using standard microelectronics and MEMS techniques. The fabricated devices are suitable for high-density system integration. The use of 3-D silicon structures allows achieving a large surface to volume ratio. The macroporous silicon structures are fabricated by electrochemical etching of silicon. This technique allows creating large structures of tubes with either straight or modulated radial profiles in depth. Furthermore, a very large aspect ratio is possible with this fabrication method. Macroporous silicon grown this way permits well-controlled structure definition with excellent repeatability and surface quality. Additionally, structure geometry can be accurately controlled to meet designer specifications. Macroporous silicon is used as one of the electrodes over which a silicon dioxide insulating layer is grown. Several insulator thicknesses have been tested. The second capacitor electrode is a solid nickel filling of the pores prepared by electroplating in a low-temperature industry standard process. The use of high-conductivity materials allows reaching small equivalent series resistance near 1 Ω. Thanks to these improvements, the presented devices are capable of operating up to 10 kHz. 84.32.Tt; 81.15.Pq; 81.05.Rm.

  9. Functional silicone copolymers and elastomers with high dielectric permittivity

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Daugaard, Anders Egede; Hvilsted, Søren

    , thereby forming a capacitor [1]. Silicone elastomers are one of the most used materials for DEs due to their high efficiency, fast response times and low viscous losses. The major disadvantage of silicone elastomers is that they possess relatively low dielectric permittivity, which means that a high...... electrical field is necessary to operate the DE. The necessary electrical field can be lowered by creating silicone elastomers with higher dielectric permittivity, i.e. with a higher energy density.The aim of this work is to create new and improved silicone elastomers with high dielectric permittivity....... This was done trough the synthesis of new functionalizable siloxane copolymers [2] that allow for the attachment of high dielectric permittivity molecules through copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) reactions. The synthesised siloxane copolymers were prepared via the tris...

  10. Magnetic properties of roller-quenched high silicon steel ribbons

    Science.gov (United States)

    Kan, T.; Ito, Y.; Shimanaka, H.

    1982-03-01

    The magnetic properties of high silicon steel ribbons prepared by the roller-quenching method were investigated, and this new material was considered to offer the potential of reducing core losses of electrical machines and power transformers.

  11. Introduction of high oxygen concentrations into silicon wafers by high-temperature diffusion

    CERN Document Server

    Casse, G L; Lemeilleur, F; Ruzin, A; Wegrzecki, M

    1999-01-01

    The tolerance of silicon detectors to hadron irradiation can be improved by the introduction of a high concentration of oxygen into the starting material. High-resistivity Floating-Zone (FZ) silicon is required for detectors used in particle physics applications. A significantly high oxygen concentration (>10/sup 17/ atoms cm/sup -3 /) cannot readily be achieved during the FZ silicon refinement. The diffusion of oxygen at elevated temperatures from a SiO/sub 2/ layer grown on both sides of a silicon wafer is a simple and effective technique to achieve high and uniform concentrations of oxygen throughout the bulk of a 300 mu m thick silicon wafer. (7 refs).

  12. Process development for high-efficiency silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Gee, J.M.; Basore, P.A.; Buck, M.E.; Ruby, D.S.; Schubert, W.K.; Silva, B.L.; Tingley, J.W.

    1991-12-31

    Fabrication of high-efficiency silicon solar cells in an industrial environment requires a different optimization than in a laboratory environment. Strategies are presented for process development of high-efficiency silicon solar cells, with a goal of simplifying technology transfer into an industrial setting. The strategies emphasize the use of statistical experimental design for process optimization, and the use of baseline processes and cells for process monitoring and quality control. 8 refs.

  13. Ultra high resolution soft x-ray tomography

    International Nuclear Information System (INIS)

    Haddad, W.S.; Trebes, J.E.; Goodman, D.M.

    1995-01-01

    Ultra high resolution three dimensional images of a microscopic test object were made with soft x-rays using a scanning transmission x-ray microscope. The test object consisted of two different patterns of gold bars on silicon nitride windows that were separated by ∼5μm. A series of nine 2-D images of the object were recorded at angles between -50 to +55 degrees with respect to the beam axis. The projections were then combined tomographically to form a 3-D image by means of an algebraic reconstruction technique (ART) algorithm. A transverse resolution of ∼1000 Angstrom was observed. Artifacts in the reconstruction limited the overall depth resolution to ∼6000 Angstrom, however some features were clearly reconstructed with a depth resolution of ∼1000 Angstrom. A specially modified ART algorithm and a constrained conjugate gradient (CCG) code were also developed as improvements over the standard ART algorithm. Both of these methods made significant improvements in the overall depth resolution bringing it down to ∼1200 Angstrom overall. Preliminary projection data sets were also recorded with both dry and re-hydrated human sperm cells over a similar angular range

  14. High Spatiotemporal Resolution Prostate MRI

    Science.gov (United States)

    2017-09-01

    vs. background. A photograph of the phan- tom is shown in Fig. 8A. Based on phantom size, it corresponds to a BMI of approximately 24. The phantom was...reconstruction. When done on the vendor system, the reconstruction time for a 32-coil DCE-MRI run is 50 s vs. 15 s on our cus- tom hardware. Lacking high speed

  15. Using High Spatial Resolution Digital Imagery

    National Research Council Canada - National Science Library

    Campbell, Michael V; Fischer, Robert L; Pangburn, Timothy; Hardenberg, Mark J

    2005-01-01

    This document is the culmination of over 3 years worth of applied research. The overall objective of this multi-year investigation was to assess the utility of high spatial resolution digital imagery to Corps civil works operations...

  16. Ultra-high resolution coded wavefront sensor

    KAUST Repository

    Wang, Congli

    2017-06-08

    Wavefront sensors and more general phase retrieval methods have recently attracted a lot of attention in a host of application domains, ranging from astronomy to scientific imaging and microscopy. In this paper, we introduce a new class of sensor, the Coded Wavefront Sensor, which provides high spatio-temporal resolution using a simple masked sensor under white light illumination. Specifically, we demonstrate megapixel spatial resolution and phase accuracy better than 0.1 wavelengths at reconstruction rates of 50 Hz or more, thus opening up many new applications from high-resolution adaptive optics to real-time phase retrieval in microscopy.

  17. Development of large area, high efficiency amorphous silicon solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, K.S.; Kim, S.; Kim, D.W. [Yu Kong Taedok Institute of Technology (Korea, Republic of)

    1996-02-01

    The objective of the research is to develop the mass-production technologies of high efficiency amorphous silicon solar cells in order to reduce the costs of solar cells and dissemination of solar cells. Amorphous silicon solar cell is the most promising option of thin film solar cells which are relatively easy to reduce the costs. The final goal of the research is to develop amorphous silicon solar cells having the efficiency of 10%, the ratio of light-induced degradation 15% in the area of 1200 cm{sup 2} and test the cells in the form of 2 Kw grid-connected photovoltaic system. (author) 35 refs., 8 tabs., 67 figs.

  18. Structure of high-resolution NMR spectra

    CERN Document Server

    Corio, PL

    2012-01-01

    Structure of High-Resolution NMR Spectra provides the principles, theories, and mathematical and physical concepts of high-resolution nuclear magnetic resonance spectra.The book presents the elementary theory of magnetic resonance; the quantum mechanical theory of angular momentum; the general theory of steady state spectra; and multiple quantum transitions, double resonance and spin echo experiments.Physicists, chemists, and researchers will find the book a valuable reference text.

  19. Monolithically Integrated High-β Nanowire Lasers on Silicon.

    Science.gov (United States)

    Mayer, B; Janker, L; Loitsch, B; Treu, J; Kostenbader, T; Lichtmannecker, S; Reichert, T; Morkötter, S; Kaniber, M; Abstreiter, G; Gies, C; Koblmüller, G; Finley, J J

    2016-01-13

    Reliable technologies for the monolithic integration of lasers onto silicon represent the holy grail for chip-level optical interconnects. In this context, nanowires (NWs) fabricated using III-V semiconductors are of strong interest since they can be grown site-selectively on silicon using conventional epitaxial approaches. Their unique one-dimensional structure and high refractive index naturally facilitate low loss optical waveguiding and optical recirculation in the active NW-core region. However, lasing from NWs on silicon has not been achieved to date, due to the poor modal reflectivity at the NW-silicon interface. We demonstrate how, by inserting a tailored dielectric interlayer at the NW-Si interface, low-threshold single mode lasing can be achieved in vertical-cavity GaAs-AlGaAs core-shell NW lasers on silicon as measured at low temperature. By exploring the output characteristics along a detection direction parallel to the NW-axis, we measure very high spontaneous emission factors comparable to nanocavity lasers (β = 0.2) and achieve ultralow threshold pump energies ≤11 pJ/pulse. Analysis of the input-output characteristics of the NW lasers and the power dependence of the lasing emission line width demonstrate the potential for high pulsation rates ≥250 GHz. Such highly efficient nanolasers grown monolithically on silicon are highly promising for the realization of chip-level optical interconnects.

  20. Single photon timing resolution and detection efficiency of the IRST silicon photo-multipliers

    International Nuclear Information System (INIS)

    Collazuol, G.; Ambrosi, G.; Boscardin, M.; Corsi, F.; Dalla Betta, G.F.; Del Guerra, A.; Dinu, N.; Galimberti, M.; Giulietti, D.; Gizzi, L.A.; Labate, L.; Llosa, G.; Marcatili, S.; Morsani, F.; Piemonte, C.; Pozza, A.; Zaccarelli, L.; Zorzi, N.

    2007-01-01

    Silicon photo-multipliers (SiPM) consist in matrices of tiny, passive quenched avalanche photo-diode cells connected in parallel via integrated resistors and operated in Geiger mode. Novel types of SiPM are being developed at FBK-IRST (Trento, Italy). Despite their classical shallow junction n-on-p structure the devices are unique in their enhanced photo-detection efficiency (PDE) for short-wavelengths and in their low level of dark rate and excess noise factor. After a summary of the extensive SiPM characterization we will focus on the study of PDE and the single photon timing resolution

  1. High-resolution Hg Chemostratigraphy

    DEFF Research Database (Denmark)

    Sial, Alcides N.; Chen, J.; Lacerda, L.D.

    2014-01-01

    There is a renewed interest in volcanism as the major trigger for dramatic climatic changes at the Cretaceous–Paleogene transition (KTB), which were accompanied by a decrease in biodiversity and mass extinction. We have used Hg contents as proxy for volcanic activity at the classical localities...... one at Stevns Klint points to a cycle of warm followed by colder climate. At Stevns Klint, Hg contents reach 250 ng g− 1 within the KTB layer (Fiskeler Member) and 45 ng.g− 1 at 1.5 m above that, while within the Scaglia Rossa Formation at Gubbio, three Hg peaks across the KTB are observed, one...... of them within the KTB layer (5.3 ng g− 1). Hg shows several peaks across the KTB in the Neuquén Basin, with up to 400 ng g− 1 in the Jagüel Formation. The phenomena that caused dramatic changes at the KTB probably expelled huge amounts of Hg into the atmosphere as recorded by these high Hg levels. A co...

  2. High resolution emission spectra of TL materials

    Energy Technology Data Exchange (ETDEWEB)

    Vilaithong, T.; Wanwilairat, S.; Rhodes, M.; Hoffmann, W.; Messarius, T

    2002-07-01

    High resolution emission spectra of several TL materials that are commonly used in dosimetry, were measured using a low cost fibre optic spectrometer containing a 2048 pixel CCD array. The spectra were taken from 177 to 890 nm with a wavelength resolution of 1.3 nm. This allowed for line width discrimination and the resolution of transitions that have not been seen so far. For rare earth doped materials like CaF{sub 2}:Tm (TLD-300) and CaF{sub 2}:Dy (TLD-200) the spectral lines were compared to the energy levels measured by Dieke and Crosswhite leading to the identification of most of the transition lines. (author)

  3. Silicon microstrip detectors for digital mammography - evaluation and spatial resolution study

    CERN Document Server

    Mali, T; Mikuz, M

    2001-01-01

    Silicon microstrip detectors were used to build an experimental X-ray imaging setup. The detectors were used in an 'edge-on' geometry, with the photons hitting the detector from the side. Efficiencies up to 90% at 20 keV photon energy could be achieved. The system was tested using a standard mammographic phantom. Images of modeled microcalcifications with various diameters down to 200 mu m and images of modeled tumors were made. Spatial resolution of the system was studied on an X-ray test pattern with frequency of line-pairs between 1 and 10l p/mm. An appropriate scanning step combined with knowledge of the system's line spread function was used to deconvolve the measured image and increase the spatial resolution. In this way the effective pixel size was reduced as much as for a factor of approx 3.

  4. Microstructure analysis of silicon nanocrystals formed from silicon rich oxide with high excess silicon: Annealing and doping effects

    Science.gov (United States)

    Nomoto, K.; Yang, T. C. J.; Ceguerra, A. V.; Zhang, T.; Lin, Z.; Breen, A.; Wu, L.; Puthen-Veettil, B.; Jia, X.; Conibeer, G.; Perez-Wurfl, I.; Ringer, S. P.

    2017-07-01

    Thin films consisting of silicon nanocrystals fabricated by high silicon content in silicon rich oxide show unique properties of decreasing resistivity and increasing light absorption while maintaining quantum confinement effects. With that said, the effect of the annealing temperature and doping element on the microscopic structure of silicon nanocrystals (Si NCs) and the film are still under research. In this study, individual intrinsic, boron-, and phosphorus-doped films are annealed at various temperatures, and their structural properties are analyzed via atom probe tomography together with glancing incidence x-ray diffraction, Raman spectroscopy (Raman), transmission electron microscopy (TEM), and energy filtered TEM. In addition, photoluminescence (PL) is performed and linked with their microstructural properties. The Si NC growth is confirmed at annealing temperatures of 1000 °C and 1100 °C. The microstructure of the Si NCs in the whole film is dramatically changed by increasing the annealing temperature from 1000 °C to 1100 °C. In addition, doping changes the arrangement of the Si NCs by assisting their penetration across the SiO2 barrier layers. This study helps to understand the relationship between the microscopic and macroscopic properties of the Si NC film, showing that the size and distribution of the Si NCs are correlated with the obtained PL profiles.

  5. Performance evaluation of a sub-millimeter spatial resolution PET detector module using a digital silicon photomultiplier coupled LGSO array

    Energy Technology Data Exchange (ETDEWEB)

    Leem, Hyun Tae [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Choi, Yong, E-mail: ychoi@sogang.ac.kr [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Kim, Kyu Bom; Lee, Sangwon [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Yamamoto, Seiichi [Department of Medical Technology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Yeom, Jung-Yeol, E-mail: jungyeol@korea.ac.kr [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of)

    2017-02-21

    In positron emission tomography (PET) for breast, brain and small animal imaging, the spatial resolution of a PET detector is crucial to obtain high quality PET images. In this study, a PET detector for sub-millimeter spatial resolution imaging purpose was assembled using 4×4 pixels of a digital silicon photomultiplier (dSiPM, DPC-3200-22-44, Philips) coupled with a 15×15 LGSO array with BaSO{sub 4} reflector, and a 1 mm thick acrylic light guide for light distribution between the dSiPM pixels. The active area of each dSiPM pixel was 3.2×3.9 mm{sup 2} and the size of each LGSO scintillator element was 0.7×0.7×6 mm{sup 3}. In this paper, we experimentally demonstrated the performance of the PET detector by measuring the energy resolution, 2D flood map, peak to valley (P/V) ratio, and coincidence resolving time (CRT). All measurements were performed at a temperature of 10±1 ℃. The average energy resolution was 15.6% (without correcting for saturation effects) at 511 keV and the best CRT was 242±5 ps. The 2D flood map obtained with an energy window of 400–600 keV demonstrated clear identification of all pixels, and the average P/V ratio of the X- and Y-directions were 7.31 and 7.81, respectively. This study demonstrated that the PET detector could be suitable for application in high resolution PET while achieving good timing resolution.

  6. Ultra-high resolution protein crystallography

    International Nuclear Information System (INIS)

    Takeda, Kazuki; Hirano, Yu; Miki, Kunio

    2010-01-01

    Many protein structures have been determined by X-ray crystallography and deposited with the Protein Data Bank. However, these structures at usual resolution (1.5< d<3.0 A) are insufficient in their precision and quantity for elucidating the molecular mechanism of protein functions directly from structural information. Several studies at ultra-high resolution (d<0.8 A) have been performed with synchrotron radiation in the last decade. The highest resolution of the protein crystals was achieved at 0.54 A resolution for a small protein, crambin. In such high resolution crystals, almost all of hydrogen atoms of proteins and some hydrogen atoms of bound water molecules are experimentally observed. In addition, outer-shell electrons of proteins can be analyzed by the multipole refinement procedure. However, the influence of X-rays should be precisely estimated in order to derive meaningful information from the crystallographic results. In this review, we summarize refinement procedures, current status and perspectives for ultra high resolution protein crystallography. (author)

  7. Large-size high-performance transparent amorphous silicon sensors for laser beam position detection

    International Nuclear Information System (INIS)

    Calderon, A.; Martinez-Rivero, C.; Matorras, F.; Rodrigo, T.; Sobron, M.; Vila, I.; Virto, A.L.; Alberdi, J.; Arce, P.; Barcala, J.M.; Calvo, E.; Ferrando, A.; Josa, M.I.; Luque, J.M.; Molinero, A.; Navarrete, J.; Oller, J.C.; Yuste, C.; Koehler, C.; Lutz, B.; Schubert, M.B.; Werner, J.H.

    2006-01-01

    We present the measured performance of a new generation of semitransparent amorphous silicon position detectors. They have a large sensitive area (30x30mm 2 ) and show good properties such as a high response (about 20mA/W), an intrinsic position resolution better than 3μm, a spatial-point reconstruction precision better than 10μm, deflection angles smaller than 10μrad and a transmission power in the visible and NIR higher than 70%

  8. High-gain bipolar detector on float-zone silicon

    Science.gov (United States)

    Han, D. J.; Batignani, G.; Del Guerra, A.; Dalla Betta, G.-F.; Boscardin, M.; Bosisio, L.; Giorgi, M.; Forti, F.

    2003-10-01

    Since the float-zone (FZ) silicon has lower contaminations and longer minority-carrier lifetime than those in Czochralski silicon and other semiconductor materials, it has potential advantages to fabricate bipolar detectors on the high-purity FZ silicon substrate to achieve a high gain at ultra-low-signal levels. The authors present preliminary experimental results on a bipolar detector fabricated on an unusual high-purity FZ silicon substrate. A backside gettering layer of phosphorus-doped polysilicon was employed to preserve the long carrier lifetime of the high-purity FZ silicon. The device has been investigated in the detection of a continuous flux of X-ray and infrared light. The bipolar detector with a circular emitter of 2 mm diameter has demonstrated high gains up to 3820 for 22 keV X-ray from a 1 mCi Cd radioactive source (the X-ray photon flux, received by the detector is estimated to be ˜7.77×10 4/s). High gain up to 4400 for 0.17 nW light with a wavelength of 0.83 μm has been observed for the same device.

  9. High-gain bipolar detector on float-zone silicon

    International Nuclear Information System (INIS)

    Han, D.J.; Batignani, G.; Guerra, A.D.A. Del; Dalla Betta, G.-F.; Boscardin, M.; Bosisio, L.; Giorgi, M.; Forti, F.

    2003-01-01

    Since the float-zone (FZ) silicon has lower contaminations and longer minority-carrier lifetime than those in Czochralski silicon and other semiconductor materials, it has potential advantages to fabricate bipolar detectors on the high-purity FZ silicon substrate to achieve a high gain at ultra-low-signal levels. The authors present preliminary experimental results on a bipolar detector fabricated on an unusual high-purity FZ silicon substrate. A backside gettering layer of phosphorus-doped polysilicon was employed to preserve the long carrier lifetime of the high-purity FZ silicon. The device has been investigated in the detection of a continuous flux of X-ray and infrared light. The bipolar detector with a circular emitter of 2 mm diameter has demonstrated high gains up to 3820 for 22 keV X-ray from a 1 mCi Cd radioactive source (the X-ray photon flux, received by the detector is estimated to be ∼7.77x10 4 /s). High gain up to 4400 for 0.17 nW light with a wavelength of 0.83 μm has been observed for the same device

  10. Use of Peltier cells in high resolution alpha spectrometry

    International Nuclear Information System (INIS)

    Bueno, C.C.; Santos, M.D.S.; Goncalves, J.A.C.

    1994-01-01

    The experiments with low-cost commercial silicon PIN photodiodes have shown the possibility of their transformation for use as alpha detectors with performance comparable with surface barrier detectors which are more expensive. Utilizing the silicon photodiode with reverse bias, an energy resolution for 241 Am alpha particles of 28 KeV and 23 KeV were obtained at room temperature and at -30 0 C respectively. (author). 4 refs, 4 figs

  11. High Resolution Sensor for Nuclear Waste Characterization

    International Nuclear Information System (INIS)

    Kanai Shah; William Higgins; Edgar V. Van Loef

    2006-01-01

    low light output. This was mostly because a large fraction of light was emitted via very slow decay components (>50 (micro)s) and as a result was not included in the light estimation performed using gamma-ray spectroscopy where the typical amplifier integration time used is 2+ ions replace the La 3+ ions in crystal lattice. This charge neutrality can be restored by codoping the Eu 2+ doped LaBr 3 crystals with ions such as Hf 4+ . The Pr 3+ doped LaBr 3 crystals provided exciting results. They exhibited very high light yield (85,000 photons/MeV) and good energy resolution. While the decay time of LaBr 3 :Pr is much slower than that for LaBr 3 :Ce, it is fast enough for many nuclear waste cleanup applications. Furthermore, it should be possible to increase the speed of LaBr 3 :Pr by adjusting its Pr 3+ concentration. The most exciting feature of LaBr 3 :Pr is that it emits in red-region and is therefore, well suited for silicon photodiode readout. In fact, LaBr 3 :Pr is the brightest scintillator in the red-region and its light yield is ∼15% higher than the light yield of LaBr 3 doped with Ce. Overall, the Phase I research has been very successful and has lead to better understanding of the lanthanum halide and related scintillators. It has also opened up some promising avenues to optimize the performance of these exciting scintillators. Based on the Phase I results, we have clearly demonstrated the feasibility of the proposed approach

  12. High Resolution Sensor for Nuclear Waste Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Kanai; Higgins, William; Van Loef, Edgar V

    2006-01-23

    large fraction of light was emitted via very slow decay components (>50 ­s) and as a result was not included in the light estimation performed using gamma-ray spectroscopy where the typical amplifier integration time used is <12 ­s. The origin of these slow component(s) is most likely related to the presence of defects caused by charge imbalance in the crystals. The charge imbalance occurs when the Eu2+ ions replace the La3+ ions in crystal lattice. This charge neutrality can be restored by codoping the Eu2+ doped LaBr3 crystals with ions such as Hf4+. The Pr3+ doped LaBr3 crystals provided exciting results. They exhibited very high light yield (85,000 photons/MeV) and good energy resolution. While the decay time of LaBr3:Pr is much slower than that for LaBr3:Ce, it is fast enough for many nuclear waste cleanup applications. Furthermore, it should be possible to increase the speed of LaBr3:Pr by adjusting its Pr3+ concentration. The most exciting feature of LaBr3:Pr is that it emits in red-region and is therefore, well suited for silicon photodiode readout. In fact, LaBr3:Pr is the brightest scintillator in the red-region and its light yield is ~15% higher than the light yield of LaBr3 doped with Ce. Overall, the Phase I research has been very successful and has lead to better understanding of the lanthanum halide and related scintillators. It has also opened up some promising avenues to optimize the performance of these exciting scintillators. Based on the Phase I results, we have clearly demonstrated the feasibility of the proposed approach.

  13. High-Resolution PET Detector. Final report

    International Nuclear Information System (INIS)

    Karp, Joel

    2014-01-01

    The objective of this project was to develop an understanding of the limits of performance for a high resolution PET detector using an approach based on continuous scintillation crystals rather than pixelated crystals. The overall goal was to design a high-resolution detector, which requires both high spatial resolution and high sensitivity for 511 keV gammas. Continuous scintillation detectors (Anger cameras) have been used extensively for both single-photon and PET scanners, however, these instruments were based on NaI(Tl) scintillators using relatively large, individual photo-multipliers. In this project we investigated the potential of this type of detector technology to achieve higher spatial resolution through the use of improved scintillator materials and photo-sensors, and modification of the detector surface to optimize the light response function.We achieved an average spatial resolution of 3-mm for a 25-mm thick, LYSO continuous detector using a maximum likelihood position algorithm and shallow slots cut into the entrance surface

  14. High-Resolution PET Detector. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Karp, Joel

    2014-03-26

    The objective of this project was to develop an understanding of the limits of performance for a high resolution PET detector using an approach based on continuous scintillation crystals rather than pixelated crystals. The overall goal was to design a high-resolution detector, which requires both high spatial resolution and high sensitivity for 511 keV gammas. Continuous scintillation detectors (Anger cameras) have been used extensively for both single-photon and PET scanners, however, these instruments were based on NaI(Tl) scintillators using relatively large, individual photo-multipliers. In this project we investigated the potential of this type of detector technology to achieve higher spatial resolution through the use of improved scintillator materials and photo-sensors, and modification of the detector surface to optimize the light response function.We achieved an average spatial resolution of 3-mm for a 25-mm thick, LYSO continuous detector using a maximum likelihood position algorithm and shallow slots cut into the entrance surface.

  15. Silicon-embedded copper nanostructure network for high energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Tianyue

    2018-01-23

    Provided herein are nanostructure networks having high energy storage, electrochemically active electrode materials including nanostructure networks having high energy storage, as well as electrodes and batteries including the nanostructure networks having high energy storage. According to various implementations, the nanostructure networks have high energy density as well as long cycle life. In some implementations, the nanostructure networks include a conductive network embedded with electrochemically active material. In some implementations, silicon is used as the electrochemically active material. The conductive network may be a metal network such as a copper nanostructure network. Methods of manufacturing the nanostructure networks and electrodes are provided. In some implementations, metal nanostructures can be synthesized in a solution that contains silicon powder to make a composite network structure that contains both. The metal nanostructure growth can nucleate in solution and on silicon nanostructure surfaces.

  16. Silicon-embedded copper nanostructure network for high energy storage

    Science.gov (United States)

    Yu, Tianyue

    2016-03-15

    Provided herein are nanostructure networks having high energy storage, electrochemically active electrode materials including nanostructure networks having high energy storage, as well as electrodes and batteries including the nanostructure networks having high energy storage. According to various implementations, the nanostructure networks have high energy density as well as long cycle life. In some implementations, the nanostructure networks include a conductive network embedded with electrochemically active material. In some implementations, silicon is used as the electrochemically active material. The conductive network may be a metal network such as a copper nanostructure network. Methods of manufacturing the nanostructure networks and electrodes are provided. In some implementations, metal nanostructures can be synthesized in a solution that contains silicon powder to make a composite network structure that contains both. The metal nanostructure growth can nucleate in solution and on silicon nanostructure surfaces.

  17. Results from the NA62 Gigatracker Prototype: A Low-Mass and sub-ns Time Resolution Silicon Pixel Detector

    Science.gov (United States)

    Fiorini, M.; Rinella, G. Aglieri; Carassiti, V.; Ceccucci, A.; Gil, E. Cortina; Ramusino, A. Cotta; Dellacasa, G.; Garbolino, S.; Jarron, P.; Kaplon, J.; Kluge, A.; Marchetto, F.; Mapelli, A.; Martin, E.; Mazza, G.; Morel, M.; Noy, M.; Nuessle, G.; Petagna, P.; Petrucci, F.; Perktold, L.; Riedler, P.; Rivetti, A.; Statera, M.; Velghe, B.

    The Gigatracker (GTK) is a hybrid silicon pixel detector developed for NA62, the experiment aimed at studying ultra-rare kaon decays at the CERN SPS. Three GTK stations will provide precise momentum and angular measurements on every track of the high intensity NA62 hadron beam with a time-tagging resolution of 150 ps. Multiple scattering and hadronic interactions of beam particles in the GTK have to be minimized to keep background events at acceptable levels, hence the total material budget is fixed to 0.5% X0 per station. In addition the calculated fluence for 100 days of running is 2×1014 1 MeV neq/cm2, comparable to the one expected for the inner trackers of LHC detectors in 10 years of operation. These requirements pose challenges for the development of an efficient and low-mass cooling system, to be operated in vacuum, and on the thinning of read-out chips to 100 μm or less. The most challenging requirement is represented by the time resolution, which can be achieved by carefully compensating for the discriminator time-walk. For this purpose, two complementary read-out architectures have been designed and produced as small-scale prototypes: the first is based on the use of a Time-over-Threshold circuit followed by a TDC shared by a group of pixels, while the other uses a constant-fraction discriminator followed by an on-pixel TDC. The readout pixel ASICs are produced in 130 nm IBM CMOS technology and bump-bonded to 200 μm thick silicon sensors. The Gigatracker detector system is described with particular emphasis on recent experimental results obtained from laboratory and beam tests of prototype bump-bonded assemblies, which show a time resolution of less than 200 ps for single hits.

  18. Single shot high resolution digital holography.

    Science.gov (United States)

    Khare, Kedar; Ali, P T Samsheer; Joseph, Joby

    2013-02-11

    We demonstrate a novel computational method for high resolution image recovery from a single digital hologram frame. The complex object field is obtained from the recorded hologram by solving a constrained optimization problem. This approach which is unlike the physical hologram replay process is shown to provide high quality image recovery even when the dc and the cross terms in the hologram overlap in the Fourier domain. Experimental results are shown for a Fresnel zone hologram of a resolution chart, intentionally recorded with a small off-axis reference beam angle. Excellent image recovery is observed without the presence of dc or twin image terms and with minimal speckle noise.

  19. Large Size High Performance Transparent Amorphous Silicon Sensors for Laser Beam Position Detection and Monitoring

    International Nuclear Information System (INIS)

    Calderon, A.; Martinez Rivero, C.; Matorras, F.; Rodrigo, T.; Sobron, M.; Vila, I.; Virto; Alberdi, J.; Arce, P.; Barcala, J. M.; Calvo, E.; Ferrando, A.; Josa, M. I.; Luque, J. M.; Molinero, A.; Navarrete, J.; Oller, J. C.; Kohler, C.; Lutz, B.; Schubert, M. B.

    2006-01-01

    We present the measured performance of a new generation of semitransparente amorphous silicon position detectors. They have a large sensitive area (30 x 30 mm2) and show good properties such as a high response (about 20 mA/W), an intinsic position resolution better than 3 m, a spatial point reconstruction precision better than 10 m, deflection angles smaller than 10 rad and a transmission power in the visible and NIR higher than 70%. In addition, multipoint alignment monitoring, using up to five sensors lined along a light path of about 5 meters, can be achieved with a resolution better than 20m. (Author)

  20. High resolution microphotonic needle for endoscopic imaging (Conference Presentation)

    Science.gov (United States)

    Tadayon, Mohammad Amin; Mohanty, Aseema; Roberts, Samantha P.; Barbosa, Felippe; Lipson, Michal

    2017-02-01

    GRIN (Graded index) lens have revolutionized micro endoscopy enabling deep tissue imaging with high resolution. The challenges of traditional GRIN lenses are their large size (when compared with the field of view) and their limited resolution. This is because of the relatively weak NA in standard graded index lenses. Here we introduce a novel micro-needle platform for endoscopy with much higher resolution than traditional GRIN lenses and a FOV that corresponds to the whole cross section of the needle. The platform is based on polymeric (SU-8) waveguide integrated with a microlens micro fabricated on a silicon substrate using a unique molding process. Due to the high index of refraction of the material the NA of the needle is much higher than traditional GRIN lenses. We tested the probe in a fluorescent dye solution (19.6 µM Alexa Flour 647 solution) and measured a numerical aperture of 0.25, focal length of about 175 µm and minimal spot size of about 1.6 µm. We show that the platform can image a sample with the field of view corresponding to the cross sectional area of the waveguide (80x100 µm2). The waveguide size can in principle be modified to vary size of the imaging field of view. This demonstration, combined with our previous work demonstrating our ability to implant the high NA needle in a live animal, shows that the proposed system can be used for deep tissue imaging with very high resolution and high field of view.

  1. Super soft silicone elastomers with high dielectric permittivity

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Hvilsted, Søren

    2015-01-01

    Dielectric elastomers (DEs) have many favourable properties. The obstacle of high driving voltages, however, limits the commercial viability of the technology at present. Driving voltage can be lowered by decreasing the Young’s modulus and increasing the dielectric permittivity of silicone...... elastomers. A decrease in Young’s modulus, however, is often accompanied by the loss of mechanical stability and thereby the lifetime of the DE. New soft elastomer matrices with high dielectric permittivity and low Young’s modulus, with no loss of mechanical stability, were prepared by two different...... approaches using chloropropyl-functional silicone polymers. The first approach was based on synthesised chloropropyl-functional copolymers that were cross-linkable and thereby formed the basis of new silicone networks with high dielectric permittivity (e.g. a 43% increase). These networks were soft without...

  2. High performance SONOS flash memory with in-situ silicon nanocrystals embedded in silicon nitride charge trapping layer

    Science.gov (United States)

    Lim, Jae-Gab; Yang, Seung-Dong; Yun, Ho-Jin; Jung, Jun-Kyo; Park, Jung-Hyun; Lim, Chan; Cho, Gyu-seok; Park, Seong-gye; Huh, Chul; Lee, Hi-Deok; Lee, Ga-Won

    2018-02-01

    In this paper, SONOS-type flash memory device with highly improved charge-trapping efficiency is suggested by using silicon nanocrystals (Si-NCs) embedded in silicon nitride (SiNX) charge trapping layer. The Si-NCs were in-situ grown by PECVD without additional post annealing process. The fabricated device shows high program/erase speed and retention property which is suitable for multi-level cell (MLC) application. Excellent performance and reliability for MLC are demonstrated with large memory window of ∼8.5 V and superior retention characteristics of 7% charge loss for 10 years. High resolution transmission electron microscopy image confirms the Si-NC formation and the size is around 1-2 nm which can be verified again in X-ray photoelectron spectroscopy (XPS) where pure Si bonds increase. Besides, XPS analysis implies that more nitrogen atoms make stable bonds at the regular lattice point. Photoluminescence spectra results also illustrate that Si-NCs formation in SiNx is an effective method to form deep trap states.

  3. High resolution Neutron and Synchrotron Powder Diffraction

    International Nuclear Information System (INIS)

    Hewat, A.W.

    1986-01-01

    The use of high-resolution powder diffraction has grown rapidly in the past years, with the development of Rietveld (1967) methods of data analysis and new high-resolution diffractometers and multidetectors. The number of publications in this area has increased from a handful per year until 1973 to 150 per year in 1984, with a ten-year total of over 1000. These papers cover a wide area of solid state-chemistry, physics and materials science, and have been grouped under 20 subject headings, ranging from catalysts to zeolites, and from battery electrode materials to pre-stressed superconducting wires. In 1985 two new high-resolution diffractometers are being commissioned, one at the SNS laboratory near Oxford, and one at the ILL in Grenoble. In different ways these machines represent perhaps the ultimate that can be achieved with neutrons and will permit refinement of complex structures with about 250 parameters and unit cell volumes of about 2500 Angstrom/sp3/. The new European Synchotron Facility will complement the Grenoble neutron diffractometers, and extend the role of high-resolution powder diffraction to the direct solution of crystal structures, pioneered in Sweden

  4. High resolution autoionization spectra in atomic uranium

    Energy Technology Data Exchange (ETDEWEB)

    Paisner, J.A.; Solarz, R.W.; Carlson, L.R.; May, C.A.; Johnson, S.A.

    1975-11-17

    High resolution (less than or equal to .5 cm/sup -1/) autoionization spectra of atomic uranium has been observed from newly identified odd parity levels between 32,660 and 34,165 cm/sup -1/. Photoionization cross sections are presented.

  5. High resolution CT in diffuse lung disease

    International Nuclear Information System (INIS)

    Webb, W.R.

    1995-01-01

    High resolution CT (computerized tomography) was discussed in detail. The conclusions were HRCT is able to define lung anatomy at the secondary lobular level and define a variety of abnormalities in patients with diffuse lung diseases. Evidence from numerous studies indicates that HRCT can play a major role in the assessment of diffuse infiltrative lung disease and is indicate clinically (95 refs.)

  6. Classification of high resolution satellite images

    OpenAIRE

    Karlsson, Anders

    2003-01-01

    In this thesis the Support Vector Machine (SVM)is applied on classification of high resolution satellite images. Sveral different measures for classification, including texture mesasures, 1st order statistics, and simple contextual information were evaluated. Additionnally, the image was segmented, using an enhanced watershed method, in order to improve the classification accuracy.

  7. Novel high resolution tactile robotic fingertips

    DEFF Research Database (Denmark)

    Drimus, Alin; Jankovics, Vince; Gorsic, Matija

    2014-01-01

    This paper describes a novel robotic fingertip based on piezoresistive rubber that can sense pressure tactile stimuli with a high spatial resolution over curved surfaces. The working principle is based on a three-layer sandwich structure (conductive electrodes on top and bottom and piezoresistive...

  8. High resolution analysis of interphase chromosome domains

    NARCIS (Netherlands)

    Visser, A. E.; Jaunin, F.; Fakan, S.; Aten, J. A.

    2000-01-01

    Chromosome territories need to be well defined at high resolution before functional aspects of chromosome organization in interphase can be explored. To visualize chromosomes by electron microscopy (EM), the DNA of Chinese hamster fibroblasts was labeled in vivo with thymidine analogue BrdU. Labeled

  9. High-Resolution, Two-Wavelength Pyrometer

    Science.gov (United States)

    Bickler, Donald B.; Henry, Paul K.; Logiurato, D. Daniel

    1989-01-01

    Modified two-color pyrometer measures temperatures of objects with high spatial resolution. Image focused on hole 0.002 in. (0.05 mm) in diameter in brass sheet near end of bundle, causing image to be distributed so fibers covered by defocused radiation from target. Pinhole ensures radiation from only small part of target scene reaches detector, thus providing required spatial resolution. By spreading radiation over bundle, pinhole ensures entire active area of detectors utilized. Produces signal as quiet as conventional instruments but with only 1/64 input radiation.

  10. High Efficiency, Low Cost Solar Cells Manufactured Using 'Silicon Ink' on Thin Crystalline Silicon Wafers

    Energy Technology Data Exchange (ETDEWEB)

    Antoniadis, H.

    2011-03-01

    Reported are the development and demonstration of a 17% efficient 25mm x 25mm crystalline Silicon solar cell and a 16% efficient 125mm x 125mm crystalline Silicon solar cell, both produced by Ink-jet printing Silicon Ink on a thin crystalline Silicon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle Silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to complete the fabrication of the Silicon Ink high efficiency solar cells. Also reported are the development and demonstration of a 18.5% efficient 125mm x 125mm monocrystalline Silicon cell, and a 17% efficient 125mm x 125mm multicrystalline Silicon cell, by utilizing high throughput Ink-jet and screen printing technologies. To achieve these objectives, Innovalight developed new high throughput processing tools to print and fuse both p and n type particle Silicon Inks in a predetermined pat-tern applied either on the front or the back of the cell. Additionally, a customized Ink-jet and screen printing systems, coupled with customized substrate handling solution, customized printing algorithms, and a customized ink drying process, in combination with a purchased turn-key line, were used to complete the high efficiency solar cells. This development work delivered a process capable of high volume producing 18.5% efficient crystalline Silicon solar cells and enabled the Innovalight to commercialize its technology by the summer of 2010.

  11. Multi-Wire Tri-Gate Silicon Nanowires Reaching Milli-pH Unit Resolution in One Micron Square Footprint

    Directory of Open Access Journals (Sweden)

    Enrico Accastelli

    2016-03-01

    Full Text Available The signal-to-noise ratio of planar ISFET pH sensors deteriorates when reducing the area occupied by the device, thus hampering the scalability of on-chip analytical systems which detect the DNA polymerase through pH measurements. Top-down nano-sized tri-gate transistors, such as silicon nanowires, are designed for high performance solid-state circuits thanks to their superior properties of voltage-to-current transduction, which can be advantageously exploited for pH sensing. A systematic study is carried out on rectangular-shaped nanowires developed in a complementary metal-oxide-semiconductor (CMOS-compatible technology, showing that reducing the width of the devices below a few hundreds of nanometers leads to higher charge sensitivity. Moreover, devices composed of several wires in parallel further increase the exposed surface per unit footprint area, thus maximizing the signal-to-noise ratio. This technology allows a sub milli-pH unit resolution with a sensor footprint of about 1 µm2, exceeding the performance of previously reported studies on silicon nanowires by two orders of magnitude.

  12. Constructing a WISE High Resolution Galaxy Atlas

    Science.gov (United States)

    Jarrett, T. H.; Masci, F.; Tsai, C. W.; Petty, S.; Cluver, M.; Assef, Roberto J.; Benford, D.; Blain, A.; Bridge, C.; Donoso, E.; hide

    2012-01-01

    After eight months of continuous observations, the Wide-field Infrared Survey Explorer (WISE) mapped the entire sky at 3.4 micron, 4.6 micron, 12 micron, and 22 micron. We have begun a dedicated WISE High Resolution Galaxy Atlas project to fully characterize large, nearby galaxies and produce a legacy image atlas and source catalog. Here we summarize the deconvolution techniques used to significantly improve the spatial resolution of WISE imaging, specifically designed to study the internal anatomy of nearby galaxies. As a case study, we present results for the galaxy NGC 1566, comparing the WISE enhanced-resolution image processing to that of Spitzer, Galaxy Evolution Explorer, and ground-based imaging. This is the first paper in a two-part series; results for a larger sample of nearby galaxies are presented in the second paper.

  13. High-resolution reconstruction for terahertz imaging.

    Science.gov (United States)

    Xu, Li-Min; Fan, Wen-Hui; Liu, Jia

    2014-11-20

    We present a high-resolution (HR) reconstruction model and algorithms for terahertz imaging, taking advantage of super-resolution methodology and algorithms. The algorithms used include projection onto a convex sets approach, iterative backprojection approach, Lucy-Richardson iteration, and 2D wavelet decomposition reconstruction. Using the first two HR reconstruction methods, we successfully obtain HR terahertz images with improved definition and lower noise from four low-resolution (LR) 22×24 terahertz images taken from our homemade THz-TDS system at the same experimental conditions with 1.0 mm pixel. Using the last two HR reconstruction methods, we transform one relatively LR terahertz image to a HR terahertz image with decreased noise. This indicates potential application of HR reconstruction methods in terahertz imaging with pulsed and continuous wave terahertz sources.

  14. High resolution imaging of boron carbide microstructures

    International Nuclear Information System (INIS)

    MacKinnon, I.D.R.; Aselage, T.; Van Deusen, S.B.

    1986-01-01

    Two samples of boron carbide have been examined using high resolution transmission electron microscopy (HRTEM). A hot-pressed B 13 C 2 sample shows a high density of variable width twins normal to (10*1). Subtle shifts or offsets of lattice fringes along the twin plane and normal to approx.(10*5) were also observed. A B 4 C powder showed little evidence of stacking disorder in crystalline regions

  15. Breathing silicon anodes for durable high-power operations.

    Science.gov (United States)

    Hwang, Chihyun; Joo, Sehun; Kang, Na-Ri; Lee, Ungju; Kim, Tae-Hee; Jeon, Yuju; Kim, Jieun; Kim, Young-Jin; Kim, Ju-Young; Kwak, Sang-Kyu; Song, Hyun-Kon

    2015-09-23

    Silicon anode materials have been developed to achieve high capacity lithium ion batteries for operating smart phones and driving electric vehicles for longer time. Serious volume expansion induced by lithiation, which is the main drawback of silicon, has been challenged by multi-faceted approaches. Mechanically rigid and stiff polymers (e.g. alginate and carboxymethyl cellulose) were considered as the good choices of binders for silicon because they grab silicon particles in a tight and rigid way so that pulverization and then break-away of the active mass from electric pathways are suppressed. Contrary to the public wisdom, in this work, we demonstrate that electrochemical performances are secured better by letting silicon electrodes breathe in and out lithium ions with volume change rather than by fixing their dimensions. The breathing electrodes were achieved by using a polysaccharide (pullulan), the conformation of which is modulated from chair to boat during elongation. The conformational transition of pullulan was originated from its α glycosidic linkages while the conventional rigid polysaccharide binders have β linkages.

  16. High Voltage Performance of Silicon Detectors Irradiated under Bias

    CERN Document Server

    Bloch, Philippe; Ciasnohova, Andrea; Dauphin, G; Golutvin, Igor; Jading, Y; Peisert, Anna; Safieh, J; Sergueev, S; Zamiatin, Nikolai

    1998-01-01

    The CMS Preshower detector contains 16 sq. m of silicon. The silicon sensors' design is being finalized by taking into account their performance after five years of operation at high luminosity. Three detectors from different manufacturers were irradiated by neutrons and photons under bias and at low temperature. Their electrical parameters and their response to alpha and beta particles were measured. The charge collection efficiency attains a plateau at around 300 V. The irradiation set-up and the results of the measurements are presented in this paper.

  17. High-voltage performance of silicon detectors irradiated under bias

    Energy Technology Data Exchange (ETDEWEB)

    Bloch, Ph.; Ciasnohova, A.; Jading, Y.; Peisert, A. E-mail: anna.elliott-peisert@cern.channa@mail.cern.ch; Golutvin, I.; Cheremukhin, A.; Sergueev, S.; Zamiatin, N.; Dauphin, G.; Safieh, J

    2000-01-11

    The CMS preshower detector contains 16 m{sup 2} of silicon. The silicon sensors' design is being finalized by taking into account their performance after five years of operation at high luminosity. Three detectors from different manufacturers were irradiated by neutrons and photons under bias and at low temperature. Their electrical parameters and their response to {alpha} and {beta} particles were measured. The charge collection efficiency attains a plateau at around 300 V. The irradiation set-up and the results of the measurements are presented in this paper.

  18. High-voltage performance of silicon detectors irradiated under bias

    CERN Document Server

    Bloch, P; Jading, Y; Peisert, Anna; Golutvin, L; Cheremuhin, A E; Sergeev, S; Zamiatin, N I; Dauphin, G; Safieh, J

    2000-01-01

    The CMS preshower detector contains 16 m/sup 2/ of silicon. The silicon sensors' design is being finalized by taking into account their performance after five years of operation at high luminosity. Three detectors from different manufacturers were irradiated by neutrons and photons under bias and at low temperature. Their electrical parameters and their response to alpha and beta particles were measured. The charge collection efficiency attains a plateau at around 300 V. The irradiation set-up and the results of the measurements are presented in this paper. (17 refs).

  19. Autoionizing states in highly ionized oxygen, fluorine and silicon

    International Nuclear Information System (INIS)

    Forester, J.P.; Peterson, R.S.; Griffin, P.M.; Pegg, D.J.; Haselton, H.H.; Liao, K.H.; Sellin, I.A.; Mowat, J.R.; Thoe, R.S.

    1975-01-01

    Autoionizing states in high Z 3-electron ions associated with core excited configurations of the type 1s2snl and 1s2pnl are reported. The electron decay-in-flight spectra of lithium-like oxygen, fluorine, and silicon ions are presented. Initial beam energies of 6.75-MeV oxygen and fluorine ions and 22.5-MeV silicon ions were used. Stripping and excitation were done by passing the beams through a thin carbon foil. The experimental technique is described. 4 figs, 1 table, 7 refs

  20. VERY HIGH RESOLUTION RF CAVITY BPM

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Marc C

    2003-05-27

    Linear collider (LC) interaction region beam sizes and component position stability requirements are expected to be a few nanometers[1]. It is important to show that the related tolerances can be achieved, with an electron beam if possible. Using recently developed component stabilization technology, very high-resolution beam position monitors (BPM's), and the ultra-low emittance beam at the KEK ATF, we plan to demonstrate the required stabilization. Our first step is to develop high-resolution RF cavity beam position monitors, using either C or X band frequencies. A C-band cavity BPM with a resolution of 25 nm has been reported in tests at FFTB [2]. By correcting for the effects of non-axial trajectories and using both position and angle BPM movers, we expect to be able to demonstrate a resolution of 2 to 3 nm over a dynamic range of {+-} 20 {micro}m. We report on the progress of the tests here.

  1. High resolution SETI: Experiences and prospects

    Science.gov (United States)

    Horowitz, Paul; Clubok, Ken

    Megachannel spectroscopy with sub-Hertz resolution constitutes an attractive strategy for a microwave search for extraterrestrial intelligence (SETI), assuming the transmission of a narrowband radiofrequency beacon. Such resolution matches the properties of the interstellar medium, and the necessary Doppler corrections provide a high degree of interference rejection. We have constructed a frequency-agile receiver with an FFT-based 8 megachannel digital spectrum analyzer, on-line signal recognition, and multithreshold archiving. We are using it to conduct a meridian transit search of the northern sky at the Harvard-Smithsonian 26-m antenna, with a second identical system scheduled to begin observations in Argentina this month. Successive 400 kHz spectra, at 0.05 Hz resolution, are searched for features characteristic of an intentional narrowband beacon transmission. These spectra are centered on guessable frequencies (such as λ21 cm), referenced successively to the local standard of rest, the galactic barycenter, and the cosmic blackbody rest frame. This search has rejected interference admirably, but is greatly limited both in total frequency coverage and sensitivity to signals other than carriers. We summarize five years of high resolution SETI at Harvard, in the context of answering the questions "How useful is narrowband SETI, how serious are its limitations, what can be done to circumvent them, and in what direction should SETI evolve?" Increasingly powerful signal processing hardware, combined with ever-higher memory densities, are particularly relevant, permitting the construction of compact and affordable gigachannel spectrum analyzers covering hundreds of megahertz of instantaneous bandwidth.

  2. Simple processing of high efficiency silicon solar cells

    International Nuclear Information System (INIS)

    Hamammu, I.M.; Ibrahim, K.

    2006-01-01

    Cost effective photovoltaic devices have been an area research since the development of the first solar cells, as cost is the major factor in their usage. Silicon solar cells have the biggest share in the photovoltaic market, though silicon os not the optimal material for solar cells. This work introduces a simplified approach for high efficiency silicon solar cell processing, by minimizing the processing steps and thereby reducing cost. The suggested procedure might also allow for the usage of lower quality materials compared to the one used today. The main features of the present work fall into: simplifying the diffusion process, edge shunt isolation and using acidic texturing instead of the standard alkaline processing. Solar cells of 17% efficiency have been produced using this procedure. Investigations on the possibility of improving the efficiency and using less quality material are still underway

  3. High-Tc superconducting antenna-coupled microbolometer on silicon

    Science.gov (United States)

    Rice, Joseph P.; Grossman, Erich N.; Borcherdt, L. J.; Rudman, D. A.

    1994-05-01

    A process is described for fabricating antenna-coupled resistive-edge microbolometers based on the high-Tc superconductor YBa2Cu3O7 (YBCO) on silicon. The YBCO and a buffer layer of yttria-stabilized zirconia (YSZ) were grown epitaxially on silicon to minimize excess electrical noise. A silicon-micromachined YBCO/YSZ air-bridge was incorporated to minimize the thermal conductance and the heat capacity. The thermal conductance of the air-bridge was measured to be 3 X 10-6 W/K at a temperature of 100 K. At an operating temperature of 89 K, the detector is estimated to have a response time of 2 microsecond(s) , a responsivity of the 1000 V/W range, and a noise-equivalent power in the 10-12 W/Hz1/2 range at 1000 Hz.

  4. High-{Tc} superconducting antenna-coupled microbolometer on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Rice, J.P.; Grossman, E.N.; Borcherdt, L.J.; Rudman, D.A. [National Inst. of Standards and Technology, Boulder, CO (United States). Cryoelectronic Metrology Group

    1994-12-31

    A process is described for fabricating antenna-coupled resistive-edge microbolometers based on the high-{Tc} superconductor YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) on silicon. The YBCO and a buffer layer of yttria-stabilized zirconia (YSZ) were grown epitaxially on silicon to minimize excess electrical noise. A silicon-micromachined YBCO/YSZ air-bridge was incorporated to minimize the thermal conductance and the heat capacity. The thermal conductance of the air-bridge was measured to be 3 {times} 10{sup {minus}6} W/K at a temperature of 100 K. At an operating temperature of 89 K, the detector is estimated to have a response time of 2 {micro}s, a responsivity in the 1,000 V/W range, and a noise-equivalent power (NEP) in the 10{sup {minus}12} W/Hz{sup 1/2} range at 1,000 Hz.

  5. High power terahertz induced carrier multiplication in Silicon

    DEFF Research Database (Denmark)

    Tarekegne, Abebe Tilahun; Pedersen, Pernille Klarskov; Iwaszczuk, Krzysztof

    2015-01-01

    The application of an intense THz field results a nonlinear transmission in high resistivity silicon. Upon increasing field strength, the transmission falls from 70% to 62% due to carrier generation through THz-induced impact ionization and subsequent absorption of the THz field by free electrons....

  6. High-resolution flurescence spectroscopy in immunoanalysis

    Energy Technology Data Exchange (ETDEWEB)

    Grubor, Nenad M. [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    The work presented in this dissertation combines highly sensitive and selective fluorescence line-narrowing spectroscopy (FLNS) detection with various modes of immunoanalytical techniques. It has been shown that FLNS is capable of directly probing molecules immunocomplexed with antibodies, eliminating analytical ambiguities that may arise from interferences that accompany traditional immunochemical techniques. Moreover, the utilization of highly cross-reactive antibodies for highly specific analyte determination has been demonstrated. Finally, they demonstrate the first example of the spectral resolution of diastereomeric analytes based on their interaction with a cross-reactive antibody.

  7. High resolution NMR theory and chemical applications

    CERN Document Server

    Becker, Edwin D

    1969-01-01

    High Resolution NMR: Theory and Chemical Applications focuses on the applications of nuclear magnetic resonance (NMR), as well as chemical shifts, lattices, and couplings. The book first offers information on the theory of NMR, including nuclear spin and magnetic moment, spin lattice relaxation, line widths, saturation, quantum mechanical description of NMR, and ringing. The text then ponders on instrumentation and techniques and chemical shifts. Discussions focus on the origin of chemical shifts, reference compounds, empirical correlations of chemical shifts, modulation and phase detection,

  8. Granulometric maps from high resolution satellite images:

    OpenAIRE

    Chopin, Franck; Mering, Catherine

    2002-01-01

    A new method of land cover mapping from satellite images using granulometric analysis is presented here. Discontinuous landscapes such as steppian bushes of semi arid regions and recently growing urban settlements are especially concerned by this study. Spatial organisations of the land cover are quantified by means of the size distribution analysis of the land cover units extracted from high resolution remotely sensed images. A granulometric map is built by automatic classification of every ...

  9. A highly integratable silicon thermal gas flow sensor

    Science.gov (United States)

    Palmer, Kristoffer; Kratz, Henrik; Nguyen, Hugo; Thornell, Greger

    2012-06-01

    Thermal flow sensors have been designed, fabricated, and characterized. All bulk material in these devices is silicon so that they are integratable in silicon-based microsystems. To mitigate heat losses and to allow for use of corrosive gases, the heating and sensing thin film titanium/platinum elements, injecting and extracting heat, respectively, from the flow, are placed outside the channel on top of a membrane consisting of alternating layers of stress-balancing silicon dioxide and silicon nitride. For the fabrication, an unconventional bond surface protection method using sputter-deposited aluminum instead of thermal silicon dioxide is used in the process steps prior to silicon fusion bonding. A method for performing lift-off on top of the transparent membrane was also developed. The sensors, measuring 9.5 × 9.5 mm2, are characterized in calorimetric and time-of-flight modes with nitrogen flow rates between 0 sccm and 300 sccm. The maximum calorimetric sensor flow signal and sensitivity are 0.95 mV and 29 µV sccm-1, respectively, with power consumption less than 40 mW. The time-of-flight mode is found to have a wider detectable flow range compared with calorimetric mode, and the time of flight measured indicates a response time of the sensor in the millisecond range. The design and operation of a sensor with high sensitivity and large flow range are discussed. A key element of this discussion is the configuration of the array of heaters and gauges along the channel to obtain different sensitivities and extend the operational range. This means that the sensor can be tailored to different flow ranges.

  10. High resolution measurement of the glycolytic rate

    Directory of Open Access Journals (Sweden)

    Carla X Bittner

    2010-09-01

    Full Text Available The glycolytic rate is sensitive to physiological activity, hormones, stress, aging and malignant transformation. Standard techniques to measure the glycolytic rate are based on radioactive isotopes, are not able to resolve single cells and have poor temporal resolution, limitations that hamper the study of energy metabolism in the brain and other organs. A new method is described in this article, which makes use of a recently-developed FRET glucose nanosensor to measure the rate of glycolysis in single cells with high temporal resolution. Used in cultured astrocytes, the method showed for the first time that glycolysis can be activated within seconds by a combination of glutamate and K+, supporting a role for astrocytes in neurometabolic and neurovascular coupling in the brain. It was also possible to make a direct comparison of metabolism in neurons and astrocytes lying in close proximity, paving the way to a high-resolution characterization of brain energy metabolism. Single-cell glycolytic rates were also measured in fibroblasts, adipocytes, myoblasts and tumor cells, showing higher rates for undifferentiated cells and significant metabolic heterogeneity within cell types. This method should facilitate the investigation of tissue metabolism at the single-cell level and is readily adaptable for high-throughput analysis.

  11. High-Resolution MRI in Rectal Cancer

    International Nuclear Information System (INIS)

    Dieguez, Adriana

    2010-01-01

    High-resolution MRI is the best method of assessing the relation of the rectal tumor with the potential circumferential resection margin (CRM). Therefore it is currently considered the method of choice for local staging of rectal cancer. The primary surgery of rectal cancer is total mesorectal excision (TME), which plane of dissection is formed by the mesorectal fascia surrounding mesorectal fat and rectum. This fascia will determine the circumferential margin of resection. At the same time, high resolution MRI allows adequate pre-operative identification of important prognostic risk factors, improving the selection and indication of therapy for each patient. This information includes, besides the circumferential margin of resection, tumor and lymph node staging, extramural vascular invasion and the description of lower rectal tumors. All these should be described in detail in the report, being part of the discussion in the multidisciplinary team, the place where the decisions involving the patient with rectal cancer will take place. The aim of this study is to provide the information necessary to understand the use of high resolution MRI in the identification of prognostic risk factors in rectal cancer. The technical requirements and standardized report for this study will be describe, as well as the anatomical landmarks of importance for the total mesorectal excision (TME), as we have said is the surgery of choice for rectal cancer. (authors) [es

  12. The STiC ASIC. High precision timing with silicon photomultipliers

    International Nuclear Information System (INIS)

    Harion, Tobias

    2015-01-01

    In recent years, Silicon Photomultipliers are being increasingly used for Time of Flight measurements in particle detectors. To utilize the high intrinsic time resolution of these sensors in detector systems, the development of specialized, highly integrated readout electronics is required. In this thesis, a mixed-signal application specific integrated circuit, named STiC, has been developed, characterized and integrated in a detector system. STiC has been specifically designed for high precision timing measurements with SiPMs, and is in particular dedicated to the EndoTOFPET-US project, which aims to achieve a coincidence time resolution of 200 ps FWHM and an energy resolution of less than 20% in an endoscopic positron emission tomography system. The chip integrates 64 high precision readout channels for SiPMs together with a digital core logic to process, store and transfer the recorded events to a data acquisition system. The performance of the chip has been validated in coincidence measurements using detector modules consisting of 3.1 x 3.1 x 15 mm 3 LYSO crystals coupled to Silicon Photomultipliers from Hamamatsu. The measurements show an energy resolution of 15% FWHM for the detection of 511 keV photons. A coincidence time resolution of 213 ps FWHM has been measured, which is among the best resolution values achieved to date with this detector topology. STiC has been integrated in the EndoTOFPET-US detector system and has been chosen as the baseline design for the readout of SiPM sensors in the Mu3e experiment.

  13. High resolution reversible color images on photonic crystal substrates.

    Science.gov (United States)

    Kang, Pilgyu; Ogunbo, Samuel O; Erickson, David

    2011-08-16

    When light is incident on a crystalline structure with appropriate periodicity, some colors will be preferentially reflected (Joannopoulos, J. D.; Meade, R. D.; Winn, J. N. Photonic crystals: molding the flow of light; Princeton University Press: Princeton, NJ, 1995; p ix, 137 pp). These photonic crystals and the structural color they generate represent an interesting method for creating reflective displays and drawing devices, since they can achieve a continuous color response and do not require back lighting (Joannopoulos, J. D.; Villeneuve, P. R.; Fan, S. H. Photonic crystals: Putting a new twist on light. Nature 1997, 386, 143-149; Graham-Rowe, D. Tunable structural colour. Nat. Photonics 2009, 3, 551-553.; Arsenault, A. C.; Puzzo, D. P.; Manners, I.; Ozin, G. A. Photonic-crystal full-colour displays. Nat. Photonics 2007, 1, 468-472; Walish, J. J.; Kang, Y.; Mickiewicz, R. A.; Thomas, E. L. Bioinspired Electrochemically Tunable Block Copolymer Full Color Pixels. Adv. Mater.2009, 21, 3078). Here we demonstrate a technique for creating erasable, high-resolution, color images using otherwise transparent inks on self-assembled photonic crystal substrates (Fudouzi, H.; Xia, Y. N. Colloidal crystals with tunable colors and their use as photonic papers. Langmuir 2003, 19, 9653-9660). Using inkjet printing, we show the ability to infuse fine droplets of silicone oils into the crystal, locally swelling it and changing the reflected color (Sirringhaus, H.; Kawase, T.; Friend, R. H.; Shimoda, T.; Inbasekaran, M.; Wu, W.; Woo, E. P. High-resolution inkjet printing of all-polymer transistor circuits. Science 2000, 290, 2123-2126). Multicolor images with resolutions as high as 200 μm are obtained from oils of different molecular weights with the lighter oils being able to penetrate deeper, yielding larger red shifts. Erasing of images is done simply by adding a low vapor pressure oil which dissolves the image, returning the substrate to its original state.

  14. Decomposition of silicon carbide at high pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Daviau, Kierstin; Lee, Kanani K. M.

    2017-11-01

    We measure the onset of decomposition of silicon carbide, SiC, to silicon and carbon (e.g., diamond) at high pressures and high temperatures in a laser-heated diamond-anvil cell. We identify decomposition through x-ray diffraction and multiwavelength imaging radiometry coupled with electron microscopy analyses on quenched samples. We find that B3 SiC (also known as 3C or zinc blende SiC) decomposes at high pressures and high temperatures, following a phase boundary with a negative slope. The high-pressure decomposition temperatures measured are considerably lower than those at ambient, with our measurements indicating that SiC begins to decompose at ~ 2000 K at 60 GPa as compared to ~ 2800 K at ambient pressure. Once B3 SiC transitions to the high-pressure B1 (rocksalt) structure, we no longer observe decomposition, despite heating to temperatures in excess of ~ 3200 K. The temperature of decomposition and the nature of the decomposition phase boundary appear to be strongly influenced by the pressure-induced phase transitions to higher-density structures in SiC, silicon, and carbon. The decomposition of SiC at high pressure and temperature has implications for the stability of naturally forming moissanite on Earth and in carbon-rich exoplanets.

  15. Investigation of Internal Amplification Effect at Planar ($p^{+}nn^{+}$) Structures Made of High Resistivity Silicon

    CERN Document Server

    Golubkov, S A; Gusev, K N; Egorov, N N; Zamiatin, N I; Katulina, S L; Kozlov, Yu F; Konkov, K A; Sandukovsky, V G; Sidorov, A I; Starostin, A S

    2004-01-01

    The first results of investigations of special strip and pixel silicon detectors are presented. The detector structures allow creating the high electric field (about 5\\cdot 10^{5} V/cm) near p-n junction. This field is high enough for avalanche multiplication of charge carriers. The possibility of internal amplification in the semiconductor detector similar to proportional amplification in gaseous counters is shown. The spectrum of -particles of the ^{238}Pu (E_{a}=5.5 MeV) demonstrates the "amplifying" peak at the energy of 70.2 MeV and energy resolution FWHM = 10.2 MeV

  16. Fabrication and electrical characterization of high aspect ratio poly-silicon filled through-silicon vias

    International Nuclear Information System (INIS)

    Dixit, Pradeep; Vehmas, Tapani; Vähänen, Sami; Monnoyer, Philippe; Henttinen, Kimmo

    2012-01-01

    This paper presents the fabrication and the electrical characterization of poly-Si filled through-silicon vias, which were etched in a 180 µm thin silicon device wafer, bonded to a handle wafer by plasma activated oxide-to-silicon bonding. Heavily doped poly-Si was used as interconnection material, which was deposited by low-pressure chemical vapor deposition. Two different via geometries, i.e. stadium shaped, and circular shaped, were tried. Sputtered aluminum metallization layers as double-side redistribution lines and contact pads, were used. Both Kelvin structures and daisy chains were fabricated and their electrical resistances were measured. The electrical resistance of a single stadium-shaped via was measured to be about 24 Ω. The electrical resistance was varying from 60 Ω to 90 Ω for two-vias daisy chains. Measured results indicate that this via-first technology can be used for varying range of sensor applications like microphone, oscillator, resonator, etc where CMOS compatibility and high temperature processing are the prime requirements. (paper)

  17. Silicon microstrip detector development in the Institute for High Energy Physics Zeuthen, GDR

    International Nuclear Information System (INIS)

    Lange, W.; Nowak, W.D.; Truetzschler, K.

    1990-01-01

    This paper reports that in regard of the growing interest to study short living particles demanding for high resolution vertex detectors the authors started to build Si microstrip detectors. The first detector generation was characterized by a small area of silicon and a readout via printed circuit board fan out. Now they can assemble detectors with larger areas and VLSI readout. A special cleanroom has been built. Equipment and tools necessary are available. Silicon wafers and thick film hybrid circuits are fabricated under collaboration by the GDR industry. Applications of their detectors were several test-runs at CERN to calibrate the L3 time expansion chamber (TEC) and the L3 muon chambers. A 10-layer telescope is designed now and it is planned to calibrate a high resolution scintillation fiber target. Future applications will be high resolution vertex detectors, e.g. L3 upgrading (LEP, CERN) or KEDR (VEPP-5, Novosibirsk). Further investigations will concern AC coupled strip detectors (single and double sided) and pixel and/or pad detectors

  18. Heavily doped silicon electrode for dielectrophoresis in high conductivity media

    Science.gov (United States)

    Zhu, Xiongfeng; Tung, Kuan-Wen; Chiou, Pei-Yu

    2017-10-01

    A hemispherically shaped, heavily doped (N++) silicon electrode is proposed to overcome the challenges of dielectrophoretic (DEP) manipulation using a conventional metal electrode operating in high conductivity media. An N++ electrode decouples the strong electric field region from the electrode interface and provides a large interface capacitance to prevent surface charging in high conductivity media, thereby effectively suppressing electrochemical reactions. Compared to a conventional metal electrode, an N++ electrode can provide 3 times higher threshold voltage and a corresponding 9-fold enhancement of maximum DEP force in 1× phosphate-buffered saline buffer with an electrical conductivity of 1 S/m. Furthermore, an N++ silicon electrode has excellent thermal conductivity and low electrical impedance, ideal for powering massively parallel DEP manipulation in high conductivity media across a large area.

  19. Dynamic high resolution imaging of rats

    International Nuclear Information System (INIS)

    Miyaoka, R.S.; Lewellen, T.K.; Bice, A.N.

    1990-01-01

    A positron emission tomography with the sensitivity and resolution to do dynamic imaging of rats would be an invaluable tool for biological researchers. In this paper, the authors determine the biological criteria for dynamic positron emission imaging of rats. To be useful, 3 mm isotropic resolution and 2-3 second time binning were necessary characteristics for such a dedicated tomograph. A single plane in which two objects of interest could be imaged simultaneously was considered acceptable. Multi-layered detector designs were evaluated as a possible solution to the dynamic imaging and high resolution imaging requirements. The University of Washington photon history generator was used to generate data to investigate a tomograph's sensitivity to true, scattered and random coincidences for varying detector ring diameters. Intrinsic spatial uniformity advantages of multi-layered detector designs over conventional detector designs were investigated using a Monte Carlo program. As a result, a modular three layered detector prototype is being developed. A module will consist of a layer of five 3.5 mm wide crystals and two layers of six 2.5 mm wide crystals. The authors believe adequate sampling can be achieved with a stationary detector system using these modules. Economical crystal decoding strategies have been investigated and simulations have been run to investigate optimum light channeling methods for block decoding strategies. An analog block decoding method has been proposed and will be experimentally evaluated to determine whether it can provide the desired performance

  20. Integrated High Resolution Monitoring of Mediterranean vegetation

    Science.gov (United States)

    Cesaraccio, Carla; Piga, Alessandra; Ventura, Andrea; Arca, Angelo; Duce, Pierpaolo; Mereu, Simone

    2017-04-01

    The study of the vegetation features in a complex and highly vulnerable ecosystems, such as Mediterranean maquis, leads to the need of using continuous monitoring systems at high spatial and temporal resolution, for a better interpretation of the mechanisms of phenological and eco-physiological processes. Near-surface remote sensing techniques are used to quantify, at high temporal resolution, and with a certain degree of spatial integration, the seasonal variations of the surface optical and radiometric properties. In recent decades, the design and implementation of global monitoring networks involved the use of non-destructive and/or cheaper approaches such as (i) continuous surface fluxes measurement stations, (ii) phenological observation networks, and (iii) measurement of temporal and spatial variations of the vegetation spectral properties. In this work preliminary results from the ECO-SCALE (Integrated High Resolution Monitoring of Mediterranean vegetation) project are reported. The project was manly aimed to develop an integrated system for environmental monitoring based on digital photography, hyperspectral radiometry , and micrometeorological techniques during three years of experimentation (2013-2016) in a Mediterranean site of Italy (Capo Caccia, Alghero). The main results concerned the analysis of chromatic coordinates indices from digital images, to characterized the phenological patterns for typical shrubland species, determining start and duration of the growing season, and the physiological status in relation to different environmental drought conditions; then the seasonal patterns of canopy phenology, was compared to NEE (Net Ecosystem Exchange) patterns, showing similarities. However, maximum values of NEE and ER (Ecosystem respiration), and short term variation, seemed mainly tuned by inter annual pattern of meteorological variables, in particular of temperature recorded in the months preceding the vegetation green-up. Finally, green signals

  1. High-resolution X-ray television and high-resolution video recorders

    International Nuclear Information System (INIS)

    Haendle, J.; Horbaschek, H.; Alexandrescu, M.

    1977-01-01

    The improved transmission properties of the high-resolution X-ray television chain described here make it possible to transmit more information per television image. The resolution in the fluoroscopic image, which is visually determined, depends on the dose rate and the inertia of the television pick-up tube. This connection is discussed. In the last few years, video recorders have been increasingly used in X-ray diagnostics. The video recorder is a further quality-limiting element in X-ray television. The development of function patterns of high-resolution magnetic video recorders shows that this quality drop may be largely overcome. The influence of electrical band width and number of lines on the resolution in the X-ray television image stored is explained in more detail. (orig.) [de

  2. High-resolution phylogenetic microbial community profiling

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Esther; Coleman-Derr, Devin; Bowman, Brett; Schwientek, Patrick; Clum, Alicia; Copeland, Alex; Ciobanu, Doina; Cheng, Jan-Fang; Gies, Esther; Hallam, Steve; Tringe, Susannah; Woyke, Tanja

    2014-03-17

    The representation of bacterial and archaeal genome sequences is strongly biased towards cultivated organisms, which belong to merely four phylogenetic groups. Functional information and inter-phylum level relationships are still largely underexplored for candidate phyla, which are often referred to as microbial dark matter. Furthermore, a large portion of the 16S rRNA gene records in the GenBank database are labeled as environmental samples and unclassified, which is in part due to low read accuracy, potential chimeric sequences produced during PCR amplifications and the low resolution of short amplicons. In order to improve the phylogenetic classification of novel species and advance our knowledge of the ecosystem function of uncultivated microorganisms, high-throughput full length 16S rRNA gene sequencing methodologies with reduced biases are needed. We evaluated the performance of PacBio single-molecule real-time (SMRT) sequencing in high-resolution phylogenetic microbial community profiling. For this purpose, we compared PacBio and Illumina metagenomic shotgun and 16S rRNA gene sequencing of a mock community as well as of an environmental sample from Sakinaw Lake, British Columbia. Sakinaw Lake is known to contain a large age of microbial species from candidate phyla. Sequencing results show that community structure based on PacBio shotgun and 16S rRNA gene sequences is highly similar in both the mock and the environmental communities. Resolution power and community representation accuracy from SMRT sequencing data appeared to be independent of GC content of microbial genomes and was higher when compared to Illumina-based metagenome shotgun and 16S rRNA gene (iTag) sequences, e.g. full-length sequencing resolved all 23 OTUs in the mock community, while iTags did not resolve closely related species. SMRT sequencing hence offers various potential benefits when characterizing uncharted microbial communities.

  3. High Performance Electronics on Flexible Silicon

    KAUST Repository

    Sevilla, Galo T.

    2016-09-01

    Over the last few years, flexible electronic systems have gained increased attention from researchers around the world because of their potential to create new applications such as flexible displays, flexible energy harvesters, artificial skin, and health monitoring systems that cannot be integrated with conventional wafer based complementary metal oxide semiconductor processes. Most of the current efforts to create flexible high performance devices are based on the use of organic semiconductors. However, inherent material\\'s limitations make them unsuitable for big data processing and high speed communications. The objective of my doctoral dissertation is to develop integration processes that allow the transformation of rigid high performance electronics into flexible ones while maintaining their performance and cost. In this work, two different techniques to transform inorganic complementary metal-oxide-semiconductor electronics into flexible ones have been developed using industry compatible processes. Furthermore, these techniques were used to realize flexible discrete devices and circuits which include metal-oxide-semiconductor field-effect-transistors, the first demonstration of flexible Fin-field-effect-transistors, and metal-oxide-semiconductors-based circuits. Finally, this thesis presents a new technique to package, integrate, and interconnect flexible high performance electronics using low cost additive manufacturing techniques such as 3D printing and inkjet printing. This thesis contains in depth studies on electrical, mechanical, and thermal properties of the fabricated devices.

  4. High resolution extremity CT for biomechanics modeling

    International Nuclear Information System (INIS)

    Ashby, A.E.; Brand, H.; Hollerbach, K.; Logan, C.M.; Martz, H.E.

    1995-01-01

    With the advent of ever more powerful computing and finite element analysis (FEA) capabilities, the bone and joint geometry detail available from either commercial surface definitions or from medical CT scans is inadequate. For dynamic FEA modeling of joints, precise articular contours are necessary to get appropriate contact definition. In this project, a fresh cadaver extremity was suspended in parafin in a lucite cylinder and then scanned with an industrial CT system to generate a high resolution data set for use in biomechanics modeling

  5. High resolution extremity CT for biomechanics modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, A.E.; Brand, H.; Hollerbach, K.; Logan, C.M.; Martz, H.E.

    1995-09-23

    With the advent of ever more powerful computing and finite element analysis (FEA) capabilities, the bone and joint geometry detail available from either commercial surface definitions or from medical CT scans is inadequate. For dynamic FEA modeling of joints, precise articular contours are necessary to get appropriate contact definition. In this project, a fresh cadaver extremity was suspended in parafin in a lucite cylinder and then scanned with an industrial CT system to generate a high resolution data set for use in biomechanics modeling.

  6. Laboratory of High resolution gamma spectrometry

    International Nuclear Information System (INIS)

    Mendez G, A.; Giber F, J.; Rivas C, I.; Reyes A, B.

    1992-01-01

    The Department of Nuclear Experimentation of the Nuclear Systems Management requests the collaboration of the Engineering unit for the supervision of the execution of the work of the High resolution Gamma spectrometry and low bottom laboratory, using the hut of the sub critic reactor of the Nuclear Center of Mexico. This laboratory has the purpose of determining the activity of special materials irradiated in nuclear power plants. In this report the architecture development, concepts, materials and diagrams for the realization of this type of work are presented. (Author)

  7. High resolution interferometry of cool stars

    Science.gov (United States)

    Lambert, D. L.

    1974-01-01

    A description is given of results obtained in a program of infrared high resolution spectroscopy of cool stars. The nature of infrared stellar spectra is considered along with questions regarding astrophysics and stellar infrared spectroscopy. An abundance analysis for alpha Ori (Betelgeuse) is conducted. The C-12/C-13 abundance ratio is examined and attention is given to the O-16/O-18 and O-16/O-17 abundance ratios. M stars and SiO vibration-rotation bands are discussed and questions regarding the characteristics of the molecular hydrogen quadrupole vibration-rotation lines are explored.

  8. High-resolution surface temperature measurements on rotating turbine blades with an infrared pyrometer

    Science.gov (United States)

    Uguccini, O. W.; Pollack, F. G.

    1976-01-01

    A high-resolution pyrometer was developed and tested on a modified turbine engine. The pyrometer was used to obtain temperature profiles of the viewed surface of turbine blades in the engine at tip speeds up to 366 meters per second. The combination of coherent fiber optics, a silicon avalanche detector, and high-speed electronics enabled surface resolution of a spot diameter of 0.05 centimeter. The data, in the form of temperature profiles, was obtained in near real time as a hard copy output from a computer display terminal. Temperatures measured with the pyrometer and with thermocouples agreed within 2 percent at temperatures between 977 to 1144 K.

  9. Development of high-thermal-conductivity silicon nitride ceramics

    Directory of Open Access Journals (Sweden)

    You Zhou

    2015-09-01

    Full Text Available Silicon nitride (Si3N4 with high thermal conductivity has emerged as one of the most promising substrate materials for the next-generation power devices. This paper gives an overview on recent developments in preparing high-thermal-conductivity Si3N4 by a sintering of reaction-bonded silicon nitride (SRBSN method. Due to the reduction of lattice oxygen content, the SRBSN ceramics could attain substantially higher thermal conductivities than the Si3N4 ceramics prepared by the conventional gas-pressure sintering of silicon nitride (SSN method. Thermal conductivity could further be improved through increasing the β/α phase ratio during nitridation and enhancing grain growth during post-sintering. Studies on fracture resistance behaviors of the SRBSN ceramics revealed that they possessed high fracture toughness and exhibited obvious R-curve behaviors. Using the SRBSN method, a Si3N4 with a record-high thermal conductivity of 177 Wm−1K−1 and a fracture toughness of 11.2 MPa m1/2 was developed. Studies on the influences of two typical metallic impurity elements, Fe and Al, on thermal conductivities of the SRBSN ceramics revealed that the tolerable content limits for the two impurities were different. While 1 wt% of impurity Fe hardly degraded thermal conductivity, only 0.01 wt% of Al caused large decrease in thermal conductivity.

  10. Characterization of high surface area silicon oxynitrides

    International Nuclear Information System (INIS)

    Lednor, P.W.; DeRuiter, R.; Emeis, K.A.

    1992-01-01

    In heterogenous catalysis, liquid or gaseous feedstocks are converted over a solid catalyst into more desirable products. Such processes form an essential part of the oil and petrochemical industries. The solid catalyst usually consists of an inorganic phase, with or without metal particles on the surface. Examples include platinum particles on gamma alumina (a reforming catalyst used in oil processing), chromium particles on silica (an ethylene polymerization catalyst) and zeolites or amorphous silica-aluminas (used as solid acids).Oxides have been widely investigated in catalysis, and silica, alumina, and aluminosilicates find application commercially on a large scale. On the other hand, non-oxide materials such as nitrides, carbides and borides have been relatively little investigated. The main reason for this has been the lack of routes to the high surface area forms usually required in catalysis. However, this situation has changed significantly in recent years, due to the interest in high surface area non-oxides as precursors to fully dense ceramics; in this paper, the authors have reviewed synthetic routes to high surface area non-oxides

  11. Screen Printing of Highly Loaded Silver Inks on Plastic Substrates Using Silicon Stencils.

    Science.gov (United States)

    Hyun, Woo Jin; Lim, Sooman; Ahn, Bok Yeop; Lewis, Jennifer A; Frisbie, C Daniel; Francis, Lorraine F

    2015-06-17

    Screen printing is a potential technique for mass-production of printed electronics; however, improvement in printing resolution is needed for high integration and performance. In this study, screen printing of highly loaded silver ink (77 wt %) on polyimide films is studied using fine-scale silicon stencils with openings ranging from 5 to 50 μm wide. This approach enables printing of high-resolution silver lines with widths as small as 22 μm. The printed silver lines on polyimide exhibit good electrical properties with a resistivity of 5.5×10(-6) Ω cm and excellent bending tolerance for bending radii greater than 5 mm (tensile strains less than 0.75%).

  12. Crystalline silicon solar cells with high resistivity emitter

    Science.gov (United States)

    Panek, P.; Drabczyk, K.; Zięba, P.

    2009-06-01

    The paper presents a part of research targeted at the modification of crystalline silicon solar cell production using screen-printing technology. The proposed process is based on diffusion from POCl3 resulting in emitter with a sheet resistance on the level of 70 Ω/□ and then, shaped by high temperature passivation treatment. The study was focused on a shallow emitter of high resistivity and on its influence on output electrical parameters of a solar cell. Secondary ion mass spectrometry (SIMS) has been employed for appropriate distinguishing the total donor doped profile. The solar cell parameters were characterized by current-voltage characteristics and spectral response (SR) methods. Some aspects playing a role in suitable manufacturing process were discussed. The situation in a photovoltaic industry with emphasis on silicon supply and current prices of solar cells, modules and photovoltaic (PV) systems are described. The economic and quantitative estimation of the PV world market is shortly discussed.

  13. Silicon Sensors for Trackers at High-Luminosity Environment

    CERN Document Server

    Peltola, Timo

    2015-01-01

    The planned upgrade of the LHC accelerator at CERN, namely the high luminosity (HL) phase of the LHC (HL-LHC foreseen for 2023), will result in a more intense radiation environment than the present tracking system was designed for. The required upgrade of the all-silicon central trackers at the ALICE, ATLAS, CMS and LHCb experiments will include higher granularity and radiation hard sensors. The radiation hardness of the new sensors must be roughly an order of magnitude higher than the one of LHC detectors. To address this, a massive R&D program is underway within the CERN RD50 collaboration "Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders" to develop silicon sensors with sufficient radiation tolerance. Research topics include the improvement of the intrinsic radiation tolerance of the sensor material and novel detector designs with benefits like reduced trapping probability (thinned and 3D sensors), maximized sensitive area (active edge sensors) and enhanced charge ...

  14. Heavy doping effects in high efficiency silicon solar cells

    Science.gov (United States)

    Lindholm, F. A.; Neugroschel, A.

    1986-01-01

    The temperature dependence of the emitter saturation current for bipolar devices was studied by varying the surface recombination velocity at the emitter surface. From this dependence, the value was derived for bandgap narrowing that is in better agreement with other determinations that were obtained from the temperature dependence measure on devices with ohmic contacts. Results of the first direct measurement of the minority-carrier transit time in a transparent heavily doped emitter layer were reported. The value was obtained by a high-frequency conductance method recently developed and used for doped Si. Experimental evidence is presented for significantly greater charge storage in highly excited silicon near room temperature than conventional theory would predict. These data are compared with various data for delta E sub G in heavily doped silicon.

  15. Synthetic Strategies for High Dielectric Constant Silicone Elastomers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt

    synthetic strategies were developed in this Ph.D. thesis, in order to create silicone elastomers with high dielectric constants and thereby higher energy densities. The work focused on maintaining important properties such as dielectric loss, electrical breakdown strength and elastic modulus...... extender’ that allowed for chemical modifications such as Cu- AAC. This route was promising for one-pot elastomer preparation and as a high dielectric constant additive to commercial silicone systems. The second approach used the borane-catalysed Piers-Rubinsztajn reaction to form spatially well...... of functional groups was identified. At a concentration of 5.6 wt% of a nitrobenzene functional group the dielectric permittivity increased 70% while at this loading important properties such as electrical breakdown strength, elastic modulus and dielectric loss were not significantly compromised. The developed...

  16. Performance of high-resolution position-sensitive detectors developed for storage-ring decay experiments

    International Nuclear Information System (INIS)

    Yamaguchi, T.; Suzaki, F.; Izumikawa, T.; Miyazawa, S.; Morimoto, K.; Suzuki, T.; Tokanai, F.; Furuki, H.; Ichihashi, N.; Ichikawa, C.; Kitagawa, A.; Kuboki, T.; Momota, S.; Nagae, D.; Nagashima, M.; Nakamura, Y.; Nishikiori, R.; Niwa, T.; Ohtsubo, T.; Ozawa, A.

    2013-01-01

    Highlights: • Position-sensitive detectors were developed for storage-ring decay spectroscopy. • Fiber scintillation and silicon strip detectors were tested with heavy ion beams. • A new fiber scintillation detector showed an excellent position resolution. • Position and energy detection by silicon strip detectors enable full identification. -- Abstract: As next generation spectroscopic tools, heavy-ion cooler storage rings will be a unique application of highly charged RI beam experiments. Decay spectroscopy of highly charged rare isotopes provides us important information relevant to the stellar conditions, such as for the s- and r-process nucleosynthesis. In-ring decay products of highly charged RI will be momentum-analyzed and reach a position-sensitive detector set-up located outside of the storage orbit. To realize such in-ring decay experiments, we have developed and tested two types of high-resolution position-sensitive detectors: silicon strips and scintillating fibers. The beam test experiments resulted in excellent position resolutions for both detectors, which will be available for future storage-ring experiments

  17. High-resolution gamma imaging; Imagerie gamma haute resolution

    Energy Technology Data Exchange (ETDEWEB)

    Parmentier, M.; Pousse, A.; Tamba, N.; Chavanelle, J.; Bakkali, A.; Kastler, B. [Centre Hospitalier Universitaire, Lab. Imagerie et Ingenierie pour la Sante, Faculte de Medecine, 25 - Besancon (France)

    2004-01-01

    Gamma imaging involves two-dimensional images of the volume distribution of a radioactive tracer previously injected into the organ under functional exploration. Our Besancon laboratory developed a gamma imager with a spatial resolution three or four times higher than a classic device, which is very useful for functional explorations on small animal, as recently demonstrated by work on myocyte apoptosis and necrosis scintigraphy in the rat. We expect progress in this promising medical imaging technology to be driven by developments in scintillating crystals and position-sensitive photomultiplier tubes, and by medical demand in applications such as early detection of breast cancer. (authors)

  18. High Temperature Oxidation and Mechanical properties of Silicon Nitride.

    Science.gov (United States)

    1980-11-30

    Continuo on r.vers side it nec..eary and iden0 y by block nmber)I : silicon nitride ~ceramics :! corrosion strength oxidation 20. 4 ACT (Continue on...concentration that optimizes densifi- cation during hot pressing can be altered to improve mechanical properties and oxidation resistance by removing Mg...the intergranular phase to improve the high-temperature- strength, creep resistance, and oxidation resistance. Preoxidation followed by surface

  19. High-Resolution Scintimammography: A Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Rachel F. Brem; Joelle M. Schoonjans; Douglas A. Kieper; Stan Majewski; Steven Goodman; Cahid Civelek

    2002-07-01

    This study evaluated a novel high-resolution breast-specific gamma camera (HRBGC) for the detection of suggestive breast lesions. Methods: Fifty patients (with 58 breast lesions) for whom a scintimammogram was clinically indicated were prospectively evaluated with a general-purpose gamma camera and a novel HRBGC prototype. The results of conventional and high-resolution nuclear studies were prospectively classified as negative (normal or benign) or positive (suggestive or malignant) by 2 radiologists who were unaware of the mammographic and histologic results. All of the included lesions were confirmed by pathology. Results: There were 30 benign and 28 malignant lesions. The sensitivity for detection of breast cancer was 64.3% (18/28) with the conventional camera and 78.6% (22/28) with the HRBGC. The specificity with both systems was 93.3% (28/30). For the 18 nonpalpable lesions, sensitivity was 55.5% (10/18) and 72.2% (13/18) with the general-purpose camera and the HRBGC, respectively. For lesions 1 cm, 7 of 15 were detected with the general-purpose camera and 10 of 15 with the HRBGC. Four lesions (median size, 8.5 mm) were detected only with the HRBGC and were missed by the conventional camera. Conclusion: Evaluation of indeterminate breast lesions with an HRBGC results in improved sensitivity for the detection of cancer, with greater improvement shown for nonpalpable and 1-cm lesions.

  20. Limiting liability via high resolution image processing

    Energy Technology Data Exchange (ETDEWEB)

    Greenwade, L.E.; Overlin, T.K.

    1996-12-31

    The utilization of high resolution image processing allows forensic analysts and visualization scientists to assist detectives by enhancing field photographs, and by providing the tools and training to increase the quality and usability of field photos. Through the use of digitized photographs and computerized enhancement software, field evidence can be obtained and processed as `evidence ready`, even in poor lighting and shadowed conditions or darkened rooms. These images, which are most often unusable when taken with standard camera equipment, can be shot in the worst of photographic condition and be processed as usable evidence. Visualization scientists have taken the use of digital photographic image processing and moved the process of crime scene photos into the technology age. The use of high resolution technology will assist law enforcement in making better use of crime scene photography and positive identification of prints. Valuable court room and investigation time can be saved and better served by this accurate, performance based process. Inconclusive evidence does not lead to convictions. Enhancement of the photographic capability helps solve one major problem with crime scene photos, that if taken with standard equipment and without the benefit of enhancement software would be inconclusive, thus allowing guilty parties to be set free due to lack of evidence.

  1. Principles of high resolution NMR in solids

    CERN Document Server

    Mehring, Michael

    1983-01-01

    The field of Nuclear Magnetic Resonance (NMR) has developed at a fascinating pace during the last decade. It always has been an extremely valuable tool to the organic chemist by supplying molecular "finger print" spectra at the atomic level. Unfortunately the high resolution achievable in liquid solutions could not be obtained in solids and physicists and physical chemists had to live with unresolved lines open to a wealth of curve fitting procedures and a vast amount of speculations. High resolution NMR in solids seemed to be a paradoxon. Broad structure­ less lines are usually encountered when dealing with NMR in solids. Only with the recent advent of mUltiple pulse, magic angle, cross-polarization, two-dimen­ sional and multiple-quantum spectroscopy and other techniques during the last decade it became possible to resolve finer details of nuclear spin interactions in solids. I have felt that graduate students, researchers and others beginning to get involved with these techniques needed a book which trea...

  2. High-resolution light microscopy of nanoforms

    Science.gov (United States)

    Vodyanoy, Vitaly; Pustovyy, Oleg; Vainrub, Arnold

    2007-09-01

    We developed a high resolution light imaging system. Diffraction gratings with 100 nm width lines as well as less than 100 nm size features of different-shaped objects are clearly visible on a calibrated microscope test slide (Vainrub et al., Optics Letters, 2006, 31, 2855). The two-point resolution increase results from a known narrowing of the central diffraction peak for the annular aperture. Better visibility and advanced contrast of the smallest features in the image are due to enhancement of high spatial frequencies in the optical transfer function. The imaging system is portable, low energy, and battery operated. It has been adapted to use in both transmitting and reflecting light. It is particularly applicable for motile nanoform systems where structure and functions can be depicted in real time. We have isolated micrometer and submicrometer particles, termed proteons, from human and animal blood. Proteons form by reversible seeded aggregation of proteins around proteon nucleating centers (PNCs). PNCs are comprised of 1-2nm metallic nanoclusters containing 40-300 atoms. Proteons are capable of spontaneous assembling into higher nanoform systems assuming structure of complicated topology. The arrangement of complex proteon system mimics the structure of a small biological cell. It has structures that imitate membrane and nucleolus or nuclei. Some of these nanoforms are motile. They interact and divide. Complex nanoform systems can spontaneously reduce to simple proteons. The physical properties of these nanoforms could shed some light on the properties of early life forms or forms at extreme conditions.

  3. High-efficiency concentrator silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sinton, R.A.; Cuevas, A.; King, R.R.; Swanson, R.M. (Stanford Univ., CA (USA). Solid-State Electronics Lab.)

    1990-11-01

    This report presents results from extensive process development in high-efficiency Si solar cells. An advanced design for a 1.56-cm{sup 2} cell with front grids achieved 26% efficiency at 90 suns. This is especially significant since this cell does not require a prismatic cover glass. New designs for simplified backside-contact solar cells were advanced from a status of near-nonfunctionality to demonstrated 21--22% for one-sun cells in sizes up to 37.5 cm{sup 2}. An efficiency of 26% was achieved for similar 0.64-cm{sup 2} concentrator cells at 150 suns. More fundamental work on dopant-diffused regions is also presented here. The recombination vs. various process and physical parameters was studied in detail for boron and phosphorous diffusions. Emitter-design studies based solidly upon these new data indicate the performance vs design parameters for a variety of the cases of most interest to solar cell designers. Extractions of p-type bandgap narrowing and the surface recombination for p- and n-type regions from these studies have a generality that extends beyond solar cells into basic device modeling. 68 refs., 50 figs.

  4. Lifetime measurements of charmed mesons with high resolution silicon detectors

    International Nuclear Information System (INIS)

    Rijk, G.A.F. de.

    1986-01-01

    In this thesis an experiment is described to measure the lifetimes of pseudoscalar charmed mesons. The experiment uses a negatively charged unseparated hadron beam of 200 GeV. The experiment is carried out with a magnetic spectrometer preceded by a beam telescope, an active target and a vertex telescope, all consisting of Si microstrip detectors. The spectrometer consists of two spectrometer magnets, 48 planes of drift chambers and 3 Cerenkov hodoscopes for the determination and identification of charged secondaries. The lifetimes of the charmed mesons are determined by measuring the length of their flight path, their momentum and their mass. The results, which are described in the thesis, are based on the analysis of part of the collected data. The production rates in the K - beam and in the π - beam are found to be in the same order of magnitude within the x F range covered. Previous experimental data on the lifetimes of charmed particles are reviewed. A theoretical interpretation is presented of the measured decay properties. (Auth.)

  5. High resolution crystal calorimetry at LHC

    International Nuclear Information System (INIS)

    Schneegans, M.; Ferrere, D.; Lebeau, M.; Vivargent, M.

    1991-01-01

    The search for Higgs bosons above Lep200 reach could be one of the main tasks of the future pp and ee colliders. In the intermediate mass region, and in particular in the range 80-140 GeV/c 2 , only the 2-photon decay mode of a Higgs produced inclusively or in association with a W, gives a good chance of observation. A 'dedicated' very high resolution calorimeter with photon angle reconstruction and pion identification capability should detect a Higgs signal with high probability. A crystal calorimeter can be considered as a conservative approach to such a detector, since a large design and operation experience already exists. The extensive R and D needed for finding a dense, fast and radiation hard crystal, is under way. Guide-lines for designing an optimum calorimeter for LHC are discussed and preliminary configurations are given. (author) 7 refs., 3 figs., 2 tabs

  6. High-quality GaN nanowires grown on Si and porous silicon by thermal evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Shekari, L., E-mail: lsg09_phy089@student.usm.my [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Ramizy, A.; Omar, K.; Hassan, H. Abu; Hassan, Z. [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer A new kind of substrate (porous silicon) was used. Black-Right-Pointing-Pointer Also this research introduces an easy and safe method to grow high quality GaN NWs. Black-Right-Pointing-Pointer This is a new growth process to decrease the cost, complexity of growth of GaN NWs. Black-Right-Pointing-Pointer It is a controllable method to synthesize GaN NWs by thermal evaporation. - Abstract: Nanowires (NWs) of GaN thin films were prepared on as-grown Si (1 1 1) and porous silicon (PS) substrates using thermal evaporation method. The film growth produced high-quality wurtzite GaN NWs. The size, morphology, and nanostructures of the crystals were investigated through scanning electron microscopy, high-resolution X-ray diffraction and photoluminescence spectroscopy. The NWs grown on porous silicon were thinner, longer and denser compared with those on as-grown Si. The energy band gap of the NWs grown on PS was larger than that of NWs on as-grown Si. This is due to the greater quantum confinement effects of the crystalline structure of the NWs grown on PS.

  7. Mesoporous Silicon-Based Anodes for High Capacity, High Performance Li-ion Batteries, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — A new high capacity anode composite based on mesoporous silicon is proposed. By virtue of a structure that resembles a pseudo one-dimensional phase, the active anode...

  8. Mesoporous Silicon-Based Anodes for High Capacity, High Performance Li-ion Batteries, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A new high capacity anode composite based on mesoporous silicon is proposed. By virtue of a structure that resembles a pseudo one-dimensional phase, the active anode...

  9. Silicon Photomultipliers in High Energy and Space Applications

    CERN Document Server

    Berra, Alessandro; Vallazza, Erik

    In recent years Silicon Photomultipliers (SiPMs) have been proposed as a new type of readout system for scintillating detectors in many experiments. SiPMs consist of a matrix of parallel-connected silicon micro-pixels, which are independent photon counters working in limited Geiger mode with very high gain. The goal of this thesis work is to describe the use of SiPMs as a readout system for plastic scintillators, both for tracking and calorimetry purposes. Different prototypes of scintillating bar tracker and shashlik calorimeters have been tested at CERN on the PS and SPS extracted beamlines. All the tests have been performed in the framework of the FACTOR (Fiber Apparatus for Calorimetry and Tracking with Optoelectronic Read-out) collaboration, a three year R&D project started in 2007 and funded by the Italian Institute of Nuclear Physics (INFN).

  10. High aspect ratio channels in glass and porous silicon

    International Nuclear Information System (INIS)

    Liang, H.D.; Dang, Z.Y.; Wu, J.F.; Kan, J.A. van; Qureshi, S.; Ynsa, M.D.; Torres-Costa, V.; Maira, A.; Venkatesan, T.V.; Breese, M.B.H.

    2017-01-01

    We have developed a micromachining process to produce high-aspect-ratio channels and holes in glass and porous silicon. Our process utilizes MeV proton beam irradiation of silicon using direct writing with a focused beam, followed by electrochemical etching. To increase throughput we have also developed another process for large area ion irradiation based on a radiation-resistant gold surface mask, allowing many square inches to be patterned. We present a study of the achievable channel width, depth and period and sidewall verticality for a range of channels which can be over 100 μm deep or 100 nm wide with aspect ratios up to 80. This process overcomes the difficulty of machining glass on a micro- and nanometer scale which has limited many areas of applications in different fields such as microelectronics and microfluidics.

  11. Method of producing high density silicon carbide product

    International Nuclear Information System (INIS)

    1981-01-01

    A method of sintering silicon carbide powders containing boron or boron - containing compounds as densification aids to produce a high-density silicon carbide ceramic material is described. It has been found that higher densification can be obtained by sintering the powders in an atmosphere containing boron. Boron may be introduced in the form of a gas, e.g. boron trichloride, mixed with the inert gas used, i.e. nitrogen, argon or helium, or boron compounds, e.g. boron carbide, may be applied to the interior of the sintering chamber as solutions or slurries. Alternatively a boron compound, per se, in the sintering chamber, or furnace components containing a significant amount of boron may be used. (U.K.)

  12. High current gain silicon-based spin transistor

    CERN Document Server

    Dennis, C L; Ensell, G J; Gregg, J F; Thompson, S M

    2003-01-01

    A silicon-based spin transistor of novel operating principle has been demonstrated in which the current gain at room temperature is 1.4 (n-type) and 0.97 (p-type). This high current gain was obtained from a hybrid metal/semiconductor analogue to the bipolar junction transistor which functions by tunnel-injecting carriers from a ferromagnetic emitter into a diffusion driven silicon base and then tunnel-collecting them via a ferromagnetic collector. The switching of the magnetic state of the collector ferromagnet controls the collector efficiency and the current gain. Furthermore, the magnetocurrent, which is determined to be 98% (140%) for p-type (n-type) in -110 Oe, is attributable to the spin-polarized base diffusion current.

  13. High aspect ratio channels in glass and porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Liang, H.D. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Nanoscience and Nanotechnology Initiative (NNI), National University of Singapore, Singapore 117411 (Singapore); Dang, Z.Y. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Wu, J.F. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore); Kan, J.A. van; Qureshi, S. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Ynsa, M.D.; Torres-Costa, V. [Department of Applied Physics, Universidad Autónoma de Madrid, Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Centro de Micro-Análisis de Materiales (CMAM), Universidad Autónoma de Madrid, Campus de Cantoblanco Edif. 22, Faraday 3, E-28049 Madrid (Spain); Maira, A. [Department of Applied Physics, Universidad Autónoma de Madrid, Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Venkatesan, T.V. [Nanoscience and Nanotechnology Initiative (NNI), National University of Singapore, Singapore 117411 (Singapore); Breese, M.B.H., E-mail: phymbhb@nus.edu.sg [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore)

    2017-03-01

    We have developed a micromachining process to produce high-aspect-ratio channels and holes in glass and porous silicon. Our process utilizes MeV proton beam irradiation of silicon using direct writing with a focused beam, followed by electrochemical etching. To increase throughput we have also developed another process for large area ion irradiation based on a radiation-resistant gold surface mask, allowing many square inches to be patterned. We present a study of the achievable channel width, depth and period and sidewall verticality for a range of channels which can be over 100 μm deep or 100 nm wide with aspect ratios up to 80. This process overcomes the difficulty of machining glass on a micro- and nanometer scale which has limited many areas of applications in different fields such as microelectronics and microfluidics.

  14. Concept for a new high resolution high intensity diffractometer

    Energy Technology Data Exchange (ETDEWEB)

    Stuhr, U. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    A concept of a new time-of-flight powder-diffractometer for a thermal neutral beam tube at SINQ is presented. The design of the instrument optimises the contradictory conditions of high intensity and high resolution. The high intensity is achieved by using many neutron pulses simultaneously. By analysing the time-angle-pattern of the detected neutrons an assignment of the neutrons to a single pulse is possible. (author) 3 figs., tab., refs.

  15. Highly Flexible Silicone Coated Neural Array for Intracochlear Electrical Stimulation

    Directory of Open Access Journals (Sweden)

    P. Bhatti

    2015-01-01

    Full Text Available We present an effective method for tailoring the flexibility of a commercial thin-film polymer electrode array for intracochlear electrical stimulation. Using a pneumatically driven dispensing system, an average 232±64 μm (mean ± SD thickness layer of silicone adhesive coating was applied to stiffen the underside of polyimide multisite arrays. Additional silicone was applied to the tip to protect neural tissue during insertion and along the array to improve surgical handling. Each array supported 20 platinum sites (180 μm dia., 250 μm pitch, spanning nearly 28 mm in length and 400 μm in width. We report an average intracochlear stimulating current threshold of 170±93 μA to evoke an auditory brainstem response in 7 acutely deafened felines. A total of 10 arrays were each inserted through a round window approach into the cochlea’s basal turn of eight felines with one delamination occurring upon insertion (preliminary results of the in vivo data presented at the 48th Annual Meeting American Neurotology Society, Orlando, FL, April 2013, and reported in Van Beek-King 2014. Using microcomputed tomography imaging (50 μm resolution, distances ranging from 100 to 565 μm from the cochlea’s central modiolus were measured. Our method combines the utility of readily available commercial devices with a straightforward postprocessing step on the order of 24 hours.

  16. ASIC-enabled High Resolution Optical Time Domain Reflectometer

    Science.gov (United States)

    Skendzic, Sandra

    (5) conclusion. Thus, it begins by providing background, basic OTDR operation, overview of ASIC functionality, and past experiments done with the ASIC for multimode fiber. Chapter 2 begins the investigation of a high resolution OTDR for single mode fiber. A though explanation of how the OTDR ASIC operates is presented in this chapter, as well as details on the OTDR scheme that has been implemented. Chapter 3 analyzes the performance of the OTDR. Chapter 4 introduces a hybrid silicon semiconductor optical amplifier and discusses its theoretical implication on the OTDR in terms of improving receiver sensitivity. Lastly, a summary of the findings and discussion of other applications lie in Chapter 5.

  17. High resolution CT of temporal bone trauma

    International Nuclear Information System (INIS)

    Youn, Eun Kyung

    1986-01-01

    Radiographic studies of the temporal bone following head trauma are indicated when there is cerebrospinal fluid otorrhea or rhinorrhoea, hearing loss, or facial nerve paralysis. Plain radiography displays only 17-30% of temporal bone fractures and pluridirectional tomography is both difficult to perform, particularly in the acutely ill patient, and less satisfactory for the demonstration of fine fractures. Consequently, high resolution CT is the imaging method of choice for the investigation of suspected temporal bone trauma and allows special resolution of fine bony detail comparable to that attainable by conventional tomography. Eight cases of temporal bone trauma examined at Korea General Hospital April 1985 through May 1986. The results were as follows: Seven patients (87%) suffered longitudinal fractures. In 6 patients who had purely conductive hearing loss, CT revealed various ossicular chain abnormality. In one patient who had neuro sensory hearing loss, CT demonstrated intract ossicular with a fracture nearing lateral wall of the lateral semicircular canal. In one patient who had mixed hearing loss, CT showed complex fracture.

  18. Detection of proximal caries with high-resolution and standard resolution digital radiographic systems

    NARCIS (Netherlands)

    Berkhout, W.E.R.; Verheij, H.G.C.; Syriopoulos, K.; Li, G.; Sanderink, G.C.H.; van der Stelt, P.F.

    2007-01-01

    Aims: The aim of this study was to: (1) compare the diagnostic accuracy of the high-resolution and standard resolution settings of four digital imaging systems for caries diagnosis and (2) compare the effect on the diagnostic accuracy of reducing the high-resolution image sizes to the standard

  19. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    DEFF Research Database (Denmark)

    Andersen, Thomas; Jensen, Robert; Christensen, M. K.

    2012-01-01

    We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal...... response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m∕Δm > 2500. The system design...... is superior to conventional batch and flow reactors with accompanying product detection by quadrupole mass spectrometry or gas chromatography not only due to the high sensitivity, fast temperature response, high mass resolution, and fast acquisition time of mass spectra but it also allows wide mass range (0...

  20. High resolution VUV facility at INDUS-1

    International Nuclear Information System (INIS)

    Krishnamurty, G.; Saraswathy, P.; Rao, P.M.R.; Mishra, A.P.; Kartha, V.B.

    1993-01-01

    Synchrotron radiation (SR) generated in the electron storage rings is an unique source for the study of atomic and molecular spectroscopy especially in the vacuum ultra violet region. Realizing the potential of this light source, efforts are in progress to develop a beamline facility at INDUS-1 to carry out high resolution atomic and molecular spectroscopy. This beam line consists of a fore-optic which is a combination of three cylindrical mirrors. The mirrors are so chosen that SR beam having a 60 mrad (horizontal) x 6 mrad (vertical) divergence is focussed onto a slit of a 6.65 metre off-plane spectrometer in Eagle Mount equipped with horizontal slit and vertical dispersion. The design of the various components of the beam line is completed. It is decided to build the spectrometer as per the requirements of the user community. Details of the various aspects of the beam line will be presented. (author). 3 figs

  1. Capillary detectors for high resolution tracking

    CERN Document Server

    Annis, P

    1997-01-01

    We present a new tracking device based on glass capillary bundles or layers filled with highly purified liquid scintillator and read out at one end by means of image intensifiers and CCD devices. A large-volume prototype consisting of 5 × 105 capillaries with a diameter of 20 μm and a length of 180 cm and read out by a megapixel CCD has been tested with muon and neutrino beams at CERN. With this prototype a two track resolution of 33 μm was achieved with passing through muons. Images of neutrino interactions in a capillary bundle have also been acquired and analysed. Read-out chains based on Electron Bombarded CCD (EBCCD) and image pipeline devices are also investigated. Preliminary results obtained with a capillary bundle read out by an EBCCD are presented.

  2. GRANULOMETRIC MAPS FROM HIGH RESOLUTION SATELLITE IMAGES

    Directory of Open Access Journals (Sweden)

    Catherine Mering

    2011-05-01

    Full Text Available A new method of land cover mapping from satellite images using granulometric analysis is presented here. Discontinuous landscapes such as steppian bushes of semi arid regions and recently growing urban settlements are especially concerned by this study. Spatial organisations of the land cover are quantified by means of the size distribution analysis of the land cover units extracted from high resolution remotely sensed images. A granulometric map is built by automatic classification of every pixel of the image according to the granulometric density inside a sliding neighbourhood. Granulometric mapping brings some advantages over traditional thematic mapping by remote sensing by focusing on fine spatial events and small changes in one peculiar category of the landscape.

  3. High resolution imaging detectors and applications

    CERN Document Server

    Saha, Swapan K

    2015-01-01

    Interferometric observations need snapshots of very high time resolution of the order of (i) frame integration of about 100 Hz or (ii) photon-recording rates of several megahertz (MHz). Detectors play a key role in astronomical observations, and since the explanation of the photoelectric effect by Albert Einstein, the technology has evolved rather fast. The present-day technology has made it possible to develop large-format complementary metal oxide–semiconductor (CMOS) and charge-coupled device (CCD) array mosaics, orthogonal transfer CCDs, electron-multiplication CCDs, electron-avalanche photodiode arrays, and quantum-well infrared (IR) photon detectors. The requirements to develop artifact-free photon shot noise-limited images are higher sensitivity and quantum efficiency, reduced noise that includes dark current, read-out and amplifier noise, smaller point-spread functions, and higher spectral bandwidth. This book aims to address such systems, technologies and design, evaluation and calibration, control...

  4. Classification of High Spatial Resolution, Hyperspectral ...

    Science.gov (United States)

    EPA announced the availability of the final report,Classification of High Spatial Resolution, Hyperspectral Remote Sensing Imagery of the Little Miami River Watershed in Southwest Ohio, USA . This report and associated land use/land cover (LULC) coverage is the result of a collaborative effort among an interdisciplinary team of scientists with the U.S. Environmental Protection Agency's (U.S. EPA's) Office of Research and Development in Cincinnati, Ohio. A primary goal of this project is to enhance the use of geography and spatial analytic tools in risk assessment, and to improve the scientific basis for risk management decisions affecting drinking water and water quality. The land use/land cover classification is derived from 82 flight lines of Compact Airborne Spectrographic Imager (CASI) hyperspectral imagery acquired from July 24 through August 9, 2002 via fixed-wing aircraft.

  5. High resolution color band pyrometer ratioing

    Science.gov (United States)

    Bickler, Donald B. (Inventor); Henry, Paul K. (Inventor); LoGiurato, D. Daniel (Inventor)

    1989-01-01

    The sensing head of a two-color band ratioing pyrometer of a known type using a fiber optic cable to couple radiation to dual detector photodiodes is improved to have high spatial resolution by focusing the radiation received through an objective lens (i.e., by focusing the image of a target area) onto an opaque sheet spaced in front of the input end of the fiber optic cable. A two-mil hole in that sheet then passes radiation to the input end of the cable. The detector has two channels, one for each color band, with an electronic-chopper stabilized current amplifier as the input stage followed by an electronic-chopper stabilized voltage amplifier.

  6. High-resolution CT of otosclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Dewen, Yang; Kodama, Takao; Tono, Tetsuya; Ochiai, Reiji; Kiyomizu, Kensuke; Suzuki, Yukiko; Yano, Takanori; Watanabe, Katsushi [Miyazaki Medical Coll., Kiyotake (Japan)

    1997-11-01

    High-resolution CT (HRCT) scans of thirty-two patients (60 ears) with the clinical diagnosis of fenestral otosclerosis were evaluated retrospectively. HRCT was performed with 1-mm-thick targeted sections and 1-mm (36 ears) or 0.5-mm (10 ears) intervals in the semiaxial projection. Seven patients (14 ears) underwent helical scanning with a 1-mm slice thickness and 1-mm/sec table speed. Forty-five ears (75%) were found to have one or more otospongiotic or otosclerotic foci on HRCT. In most instances (30 ears), the otospongiotic foci were found in the region of the fissula ante fenestram. No significant correlations between CT findings and air conduction threshold were observed. We found a significant relationship between lesions of the labyrinthine capsule and sensorineural hearing loss. We conclude that HRCT is a valuable modality for diagnosing otosclerosis, especially when otospongiotic focus is detected. (author)

  7. High-resolution CT of otosclerosis

    International Nuclear Information System (INIS)

    Dewen, Yang; Kodama, Takao; Tono, Tetsuya; Ochiai, Reiji; Kiyomizu, Kensuke; Suzuki, Yukiko; Yano, Takanori; Watanabe, Katsushi

    1997-01-01

    High-resolution CT (HRCT) scans of thirty-two patients (60 ears) with the clinical diagnosis of fenestral otosclerosis were evaluated retrospectively. HRCT was performed with 1-mm-thick targeted sections and 1-mm (36 ears) or 0.5-mm (10 ears) intervals in the semiaxial projection. Seven patients (14 ears) underwent helical scanning with a 1-mm slice thickness and 1-mm/sec table speed. Forty-five ears (75%) were found to have one or more otospongiotic or otosclerotic foci on HRCT. In most instances (30 ears), the otospongiotic foci were found in the region of the fissula ante fenestram. No significant correlations between CT findings and air conduction threshold were observed. We found a significant relationship between lesions of the labyrinthine capsule and sensorineural hearing loss. We conclude that HRCT is a valuable modality for diagnosing otosclerosis, especially when otospongiotic focus is detected. (author)

  8. High-resolution transcriptome of human macrophages.

    Directory of Open Access Journals (Sweden)

    Marc Beyer

    Full Text Available Macrophages are dynamic cells integrating signals from their microenvironment to develop specific functional responses. Although, microarray-based transcriptional profiling has established transcriptional reprogramming as an important mechanism for signal integration and cell function of macrophages, current knowledge on transcriptional regulation of human macrophages is far from complete. To discover novel marker genes, an area of great need particularly in human macrophage biology but also to generate a much more thorough transcriptome of human M1- and M1-like macrophages, we performed RNA sequencing (RNA-seq of human macrophages. Using this approach we can now provide a high-resolution transcriptome profile of human macrophages under classical (M1-like and alternative (M2-like polarization conditions and demonstrate a dynamic range exceeding observations obtained by previous technologies, resulting in a more comprehensive understanding of the transcriptome of human macrophages. Using this approach, we identify important gene clusters so far not appreciated by standard microarray techniques. In addition, we were able to detect differential promoter usage, alternative transcription start sites, and different coding sequences for 57 gene loci in human macrophages. Moreover, this approach led to the identification of novel M1-associated (CD120b, TLR2, SLAMF7 as well as M2-associated (CD1a, CD1b, CD93, CD226 cell surface markers. Taken together, these data support that high-resolution transcriptome profiling of human macrophages by RNA-seq leads to a better understanding of macrophage function and will form the basis for a better characterization of macrophages in human health and disease.

  9. Brain inspired high performance electronics on flexible silicon

    KAUST Repository

    Sevilla, Galo T.

    2014-06-01

    Brain\\'s stunning speed, energy efficiency and massive parallelism makes it the role model for upcoming high performance computation systems. Although human brain components are a million times slower than state of the art silicon industry components [1], they can perform 1016 operations per second while consuming less power than an electrical light bulb. In order to perform the same amount of computation with today\\'s most advanced computers, the output of an entire power station would be needed. In that sense, to obtain brain like computation, ultra-fast devices with ultra-low power consumption will have to be integrated in extremely reduced areas, achievable only if brain folded structure is mimicked. Therefore, to allow brain-inspired computation, flexible and transparent platform will be needed to achieve foldable structures and their integration on asymmetric surfaces. In this work, we show a new method to fabricate 3D and planar FET architectures in flexible and semitransparent silicon fabric without comprising performance and maintaining cost/yield advantage offered by silicon-based electronics.

  10. Diamond and silicon pixel detectors in high radiation environments

    Energy Technology Data Exchange (ETDEWEB)

    Tsung, Jieh-Wen

    2012-10-15

    Diamond pixel detector is a promising candidate for tracking of collider experiments because of the good radiation tolerance of diamond. The diamond pixel detector must withstand the radiation damage from 10{sup 16} particles per cm{sup 2}, which is the expected total fluence in High Luminosity Large Hadron Collider. The performance of diamond and silicon pixel detectors are evaluated in this research in terms of the signal-to-noise ratio (SNR). Single-crystal diamond pixel detectors with the most recent readout chip ATLAS FE-I4 are produced and characterized. Based on the results of the measurement, the SNR of diamond pixel detector is evaluated as a function of radiation fluence, and compared to that of planar-silicon ones. The deterioration of signal due to radiation damage is formulated using the mean free path of charge carriers in the sensor. The noise from the pixel readout circuit is simulated and calculated with leakage current and input capacitance to the amplifier as important parameters. The measured SNR shows good agreement with the calculated and simulated results, proving that the performance of diamond pixel detectors can exceed the silicon ones if the particle fluence is more than 10{sup 15} particles per cm{sup 2}.

  11. High resolution mid-infrared spectroscopy based on frequency upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Hu, Qi; Tidemand-Lichtenberg, Peter

    2013-01-01

    signals can be analyzed. The obtainable frequency resolution is usually in the nm range where sub nm resolution is preferred in many applications, like gas spectroscopy. In this work we demonstrate how to obtain sub nm resolution when using upconversion. In the presented realization one object point...... high resolution spectral performance by observing emission from hot water vapor in a butane gas burner....

  12. A high resolution solar atlas for fluorescence calculations

    Science.gov (United States)

    Hearn, M. F.; Ohlmacher, J. T.; Schleicher, D. G.

    1983-01-01

    The characteristics required of a solar atlas to be used for studying the fluorescence process in comets are examined. Several sources of low resolution data were combined to provide an absolutely calibrated spectrum from 2250 A to 7000A. Three different sources of high resolution data were also used to cover this same spectral range. The low resolution data were then used to put each high resolution spectrum on an absolute scale. The three high resolution spectra were then combined in their overlap regions to produce a single, absolutely calibrated high resolution spectrum over the entire spectral range.

  13. High-Resolution Integrated Optical System

    Science.gov (United States)

    Prakapenka, V. B.; Goncharov, A. F.; Holtgrewe, N.; Greenberg, E.

    2017-12-01

    Raman and optical spectroscopy in-situ at extreme high pressure and temperature conditions relevant to the planets' deep interior is a versatile tool for characterization of wide range of properties of minerals essential for understanding the structure, composition, and evolution of terrestrial and giant planets. Optical methods, greatly complementing X-ray diffraction and spectroscopy techniques, become crucial when dealing with light elements. Study of vibrational and optical properties of minerals and volatiles, was a topic of many research efforts in past decades. A great deal of information on the materials properties under extreme pressure and temperature has been acquired including that related to structural phase changes, electronic transitions, and chemical transformations. These provide an important insight into physical and chemical states of planetary interiors (e.g. nature of deep reservoirs) and their dynamics including heat and mass transport (e.g. deep carbon cycle). Optical and vibrational spectroscopy can be also very instrumental for elucidating the nature of the materials molten states such as those related to the Earth's volatiles (CO2, CH4, H2O), aqueous fluids and silicate melts, planetary ices (H2O, CH4, NH3), noble gases, and H2. The optical spectroscopy study performed concomitantly with X-ray diffraction and spectroscopy measurements at the GSECARS beamlines on the same sample and at the same P-T conditions would greatly enhance the quality of this research and, moreover, will provide unique new information on chemical state of matter. The advanced high-resolution user-friendly integrated optical system is currently under construction and expected to be completed by 2018. In our conceptual design we have implemented Raman spectroscopy with five excitation wavelengths (266, 473, 532, 660, 946 nm), confocal imaging, double sided IR laser heating combined with high temperature Raman (including coherent anti-Stokes Raman scattering) and

  14. High-resolution downscaling for hydrological management

    Science.gov (United States)

    Ulbrich, Uwe; Rust, Henning; Meredith, Edmund; Kpogo-Nuwoklo, Komlan; Vagenas, Christos

    2017-04-01

    Hydrological modellers and water managers require high-resolution climate data to model regional hydrologies and how these may respond to future changes in the large-scale climate. The ability to successfully model such changes and, by extension, critical infrastructure planning is often impeded by a lack of suitable climate data. This typically takes the form of too-coarse data from climate models, which are not sufficiently detailed in either space or time to be able to support water management decisions and hydrological research. BINGO (Bringing INnovation in onGOing water management; ) aims to bridge the gap between the needs of hydrological modellers and planners, and the currently available range of climate data, with the overarching aim of providing adaptation strategies for climate change-related challenges. Producing the kilometre- and sub-daily-scale climate data needed by hydrologists through continuous simulations is generally computationally infeasible. To circumvent this hurdle, we adopt a two-pronged approach involving (1) selective dynamical downscaling and (2) conditional stochastic weather generators, with the former presented here. We take an event-based approach to downscaling in order to achieve the kilometre-scale input needed by hydrological modellers. Computational expenses are minimized by identifying extremal weather patterns for each BINGO research site in lower-resolution simulations and then only downscaling to the kilometre-scale (convection permitting) those events during which such patterns occur. Here we (1) outline the methodology behind the selection of the events, and (2) compare the modelled precipitation distribution and variability (preconditioned on the extremal weather patterns) with that found in observations.

  15. High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

    Science.gov (United States)

    Bozak, Karin E.; Pinero, Luis R.; Scheidegger, Robert J.; Aulisio, Michael V.; Gonzalez, Marcelo C.; Birchenough, Arthur G.

    2015-01-01

    A silicon carbide brassboard power processing unit has been developed by the NASA Glenn Research Center in Cleveland, Ohio. The power processing unit operates from two sources: a nominal 300 Volt high voltage input bus and a nominal 28 Volt low voltage input bus. The design of the power processing unit includes four low voltage, low power auxiliary supplies, and two parallel 7.5 kilowatt (kW) discharge power supplies that are capable of providing up to 15 kilowatts of total power at 300 to 500 Volts (V) to the thruster. Additionally, the unit contains a housekeeping supply, high voltage input filter, low voltage input filter, and master control board, such that the complete brassboard unit is capable of operating a 12.5 kilowatt Hall effect thruster. The performance of the unit was characterized under both ambient and thermal vacuum test conditions, and the results demonstrate exceptional performance with full power efficiencies exceeding 97%. The unit was also tested with a 12.5kW Hall effect thruster to verify compatibility and output filter specifications. With space-qualified silicon carbide or similar high voltage, high efficiency power devices, this would provide a design solution to address the need for high power electric propulsion systems.

  16. High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

    Science.gov (United States)

    Bozak, Karin E.; Pinero, Luis R.; Scheidegger, Robert J.; Aulisio, Michael V.; Gonzalez, Marcelo C.; Birchenough, Arthur G.

    2015-01-01

    A silicon carbide brassboard power processing unit has been developed by the NASA Glenn Research Center in Cleveland, Ohio. The power processing unit operates from two sources - a nominal 300-Volt high voltage input bus and a nominal 28-Volt low voltage input bus. The design of the power processing unit includes four low voltage, low power supplies that provide power to the thruster auxiliary supplies, and two parallel 7.5 kilowatt power supplies that are capable of providing up to 15 kilowatts of total power at 300-Volts to 500-Volts to the thruster discharge supply. Additionally, the unit contains a housekeeping supply, high voltage input filter, low voltage input filter, and master control board, such that the complete brassboard unit is capable of operating a 12.5 kilowatt Hall Effect Thruster. The performance of unit was characterized under both ambient and thermal vacuum test conditions, and the results demonstrate the exceptional performance with full power efficiencies exceeding 97. With a space-qualified silicon carbide or similar high voltage, high efficiency power device, this design could evolve into a flight design for future missions that require high power electric propulsion systems.

  17. HIGH RESOLUTION AIRBORNE SHALLOW WATER MAPPING

    Directory of Open Access Journals (Sweden)

    F. Steinbacher

    2012-07-01

    Full Text Available In order to meet the requirements of the European Water Framework Directive (EU-WFD, authorities face the problem of repeatedly performing area-wide surveying of all kinds of inland waters. Especially for mid-sized or small rivers this is a considerable challenge imposing insurmountable logistical efforts and costs. It is therefore investigated if large-scale surveying of a river system on an operational basis is feasible by employing airborne hydrographic laser scanning. In cooperation with the Bavarian Water Authority (WWA Weilheim a pilot project was initiated by the Unit of Hydraulic Engineering at the University of Innsbruck and RIEGL Laser Measurement Systems exploiting the possibilities of a new LIDAR measurement system with high spatial resolution and high measurement rate to capture about 70 km of riverbed and foreland for the river Loisach in Bavaria/Germany and the estuary and parts of the shoreline (about 40km in length of lake Ammersee. The entire area surveyed was referenced to classic terrestrial cross-section surveys with the aim to derive products for the monitoring and managing needs of the inland water bodies forced by the EU-WFD. The survey was performed in July 2011 by helicopter and airplane and took 3 days in total. In addition, high resolution areal images were taken to provide an optical reference, offering a wide range of possibilities on further research, monitoring, and managing responsibilities. The operating altitude was about 500 m to maintain eye-safety, even for the aided eye, the airspeed was about 55 kts for the helicopter and 75 kts for the aircraft. The helicopter was used in the alpine regions while the fixed wing aircraft was used in the plains and the urban area, using appropriate scan rates to receive evenly distributed point clouds. The resulting point density ranged from 10 to 25 points per square meter. By carefully selecting days with optimum water quality, satisfactory penetration down to the river

  18. High performance high-κ/metal gate complementary metal oxide semiconductor circuit element on flexible silicon

    KAUST Repository

    Sevilla, Galo T.

    2016-02-29

    Thinned silicon based complementary metal oxide semiconductor(CMOS)electronics can be physically flexible. To overcome challenges of limited thinning and damaging of devices originated from back grinding process, we show sequential reactive ion etching of silicon with the assistance from soft polymeric materials to efficiently achieve thinned (40 μm) and flexible (1.5 cm bending radius) silicon based functional CMOSinverters with high-κ/metal gate transistors. Notable advances through this study shows large area of silicon thinning with pre-fabricated high performance elements with ultra-large-scale-integration density (using 90 nm node technology) and then dicing of such large and thinned (seemingly fragile) pieces into smaller pieces using excimer laser. The impact of various mechanical bending and bending cycles show undeterred high performance of flexible siliconCMOSinverters. Future work will include transfer of diced silicon chips to destination site, interconnects, and packaging to obtain fully flexible electronic systems in CMOS compatible way.

  19. High temperature corrosion of silicon carbide and silicon nitride in the presence of chloride compound

    International Nuclear Information System (INIS)

    McNallan, M.

    1993-01-01

    Silicon carbide and silicon nitride are resistant to oxidation because a protective silicon dioxide films on their surfaces in most oxidizing environments. Chloride compounds can attack the surface in two ways: 1) chlorine can attack the silicon directly to form a volatile silicon chloride compound or 2) alkali compounds combined with the chlorine can be transported to the surface where they flux the silica layer by forming stable alkali silicates. Alkali halides have enough vapor pressure that a sufficient quantity of alkali species to cause accelerated corrosion can be transported to the ceramic surface without the formation of a chloride deposit. When silicon carbide is attacked simultaneously by chlorine and oxygen, the corrosion products include both volatile and condensed spices. Silicon nitride is much more resistance to this type of attack than silicon carbide. Silicon based ceramics are exposed to oxidizing gases in the presence of alkali chloride vapors, the rate of corrosion is controlled primarily by the driving force for the formation of alkali silicate, which can be quantified as the activity of the alkali oxide in equilibrium with the corrosive gas mixture. In a gas mixture containing a fixed partial pressure of KCl, the rate of corrosion is accelerated by increasing the concentration of water vapor and inhibited by increasing the concentration of HCl. Similar results have been obtained for mixtures containing other alkalis and halogens. (Orig./A.B.)

  20. Fatigue in a heat treatable high silicon containing aluminium alloy

    Science.gov (United States)

    González, J. A.; Talamantes-Silva, J.; Valtierra, S.; Colás, Rafael

    2017-05-01

    The use of cast aluminium alloys in automobiles contributes to reductions in weight and fuel consumption without impairing the safety for the occupants or the performance of the car. Most of the alloys used are heat treatable hypoeutectic Al-Si alloys, which have the drawback of exhibiting low wear resistance. So industry relies in wear resistant alloys, such as grey iron, for the liners of the combustion chambers in engine blocks, which increase the weight of the engine. Therefore, it is of interest to cast high silicon containing alloys into engine components that are able to resist wear while maintaining the mechanical properties required by the components. This work presents the result of the work carried out in a high silicon containing heat treatable aluminium alloy as it is subjected to high cycle fatigue. The alloy was prepared and cast in ingots designed to promote one dimensional solidification gradient to obtain samples to study the high cycle fatigue. The material was machined into hour-glass specimens that were tested at room temperature in a servohydraulic machine under load control following the stair case method. The results show that the resistance to fatigue depends on the microstructure of the sample, as the fatigue cracks originate in pores close to the surface of the sample and propagate through the eutectic aggregate. The results from this work are compared with those from previously obtained with hypoeutectic alloys.

  1. Resolution enhancement of low quality videos using a high-resolution frame

    NARCIS (Netherlands)

    Pham, T.Q.; Van Vliet, L.J.; Schutte, K.

    2006-01-01

    This paper proposes an example-based Super-Resolution (SR) algorithm of compressed videos in the Discrete Cosine Transform (DCT) domain. Input to the system is a Low-Resolution (LR) compressed video together with a High-Resolution (HR) still image of similar content. Using a training set of

  2. Silicon-Light: a European FP7 Project Aiming at High Efficiency Thin Film Silicon Solar Cells on Foil

    DEFF Research Database (Denmark)

    Soppe, W.; Haug, F.-J.; Couty, P.

    2011-01-01

    Silicon-Light is a European FP7 project, which started January 1st, 2010 and aims at development of low cost, high-efficiency thin film silicon solar cells on foil. Three main routes are explored to achieve these goals: a) advanced light trapping by implementing nanotexturization through UV Nano...... calculations of ideal nanotextures for light trapping in thin film silicon solar cells; the fabrication of masters and the replication and roll-to-roll fabrication of these nanotextures. Further, results on ITO variants with improved work function are presented. Finally, the status of cell fabrication on foils...... with nanotexture is shown. Microcrystalline and amorphous silicon single junction cells with stable efficiencies with more than 8 % have been made, paving the way towards a-Si/ c-Si tandem cells with more than 11% efficiency....

  3. Properties and Structure of High-Silicone Austempered Ductile Iron

    Directory of Open Access Journals (Sweden)

    Krzyńska A.

    2014-06-01

    Full Text Available The results presented in this paper are a continuation of the previously published studies. The results of hest treatment of ductile iron with content 3,66%Si and 3,80% Si were produced. The experimental castings were subjected to austempering process for time 30, 60 and 90 minutes at temperature 300°C. The mechanical properties of heat treated specimens were studied using tensile testing and hardness measurement, while microstructures were evaluated with conventional metallographic observations. It was again stated that austempering of high silicone ferritic matrix ductile iron allowed producing ADI-type cast iron with mechanical properties comparable with standard ADI.

  4. High-field EPR spectroscopy of thermal donors in silicon

    DEFF Research Database (Denmark)

    Dirksen, R.; Rasmussen, F.B.; Gregorkiewicz, T.

    1997-01-01

    Thermal donors generated in p-type boron-doped Czochralski-grown silicon by a 450 degrees C heat treatment have been studied by high-field magnetic resonance spectroscopy. In the experiments conducted at a microwave frequency of 140 GHz and in a magnetic field of approximately 5 T four individual...... thermal donors species could be resolved. These were observed in their singly ionized TD+ charge state. For the first time in the four decades of thermal donor research the g tensor values for specific members of the Si-NL8 family are given. Also the symmetry of the observed species is discussed....

  5. High Spectral Resolution Lidar (HSRL) Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Goldsmith, John [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2016-04-01

    High Spectral Resolution Lidar (HSRL) systems provide vertical profiles of optical depth, backscatter cross-section, depolarization, and backscatter phase function. All HSRL measurements are absolutely calibrated by reference to molecular scattering, which is measured at each point in the lidar profile. Like the Raman lidar but unlike simple backscatter lidars such as the micropulse lidar, the HSRL can measure backscatter cross-sections and optical depths without prior assumptions about the scattering properties of the atmosphere. The depolarization observations also allow robust discrimination between ice and water clouds. In addition, rigorous error estimates can be computed for all measurements. A very narrow, angular field of view reduces multiple scattering contributions. The small field of view, coupled with a narrow optical bandwidth, nearly eliminates noise due to scattered sunlight. There are two operational U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility HSRL systems, one at the Barrow North Slope of Alaska (NSA) site and the other in the second ARM Mobile Facility (AMF2) collection of instrumentation.

  6. Passivating electron contact based on highly crystalline nanostructured silicon oxide layers for silicon solar cells

    Czech Academy of Sciences Publication Activity Database

    Stuckelberger, J.; Nogay, G.; Wyss, P.; Jeangros, Q.; Allebe, Ch.; Debrot, F.; Niquille, X.; Ledinský, Martin; Fejfar, Antonín; Despeisse, M.; Haug, F.J.; Löper, P.; Ballif, C.

    2016-01-01

    Roč. 158, Dec (2016), s. 2-10 ISSN 0927-0248 R&D Projects: GA MŠk LM2015087 Institutional support: RVO:68378271 Keywords : surface passivation * passivating contact * nanostructure * silicon oxide * nanocrystalline * microcrystalline * poly-silicon * crystallization * Raman * transmission line measurement Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.784, year: 2016

  7. Broadband infrared photoluminescence in silicon nanowires with high density stacking faults.

    Science.gov (United States)

    Li, Yang; Liu, Zhihong; Lu, Xiaoxiang; Su, Zhihua; Wang, Yanan; Liu, Rui; Wang, Dunwei; Jian, Jie; Lee, Joon Hwan; Wang, Haiyan; Yu, Qingkai; Bao, Jiming

    2015-02-07

    Making silicon an efficient light-emitting material is an important goal of silicon photonics. Here we report the observation of broadband sub-bandgap photoluminescence in silicon nanowires with a high density of stacking faults. The photoluminescence becomes stronger and exhibits a blue shift under higher laser powers. The super-linear dependence on excitation intensity indicates a strong competition between radiative and defect-related non-radiative channels, and the spectral blue shift is ascribed to the band filling effect in the heterostructures of wurtzite silicon and cubic silicon created by stacking faults.

  8. The High-Resolution IRAS Galaxy Atlas

    Science.gov (United States)

    Cao, Yu; Terebey, Susan; Prince, Thomas A.; Beichman, Charles A.; Oliversen, R. (Technical Monitor)

    1997-01-01

    An atlas of the Galactic plane (-4.7 deg is less than b is less than 4.7 deg), along with the molecular clouds in Orion, rho Oph, and Taurus-Auriga, has been produced at 60 and 100 microns from IRAS data. The atlas consists of resolution-enhanced co-added images with 1 min - 2 min resolution and co-added images at the native IRAS resolution. The IRAS Galaxy Atlas, together with the Dominion Radio Astrophysical Observatory H(sub I) line/21 cm continuum and FCRAO CO (1-0) Galactic plane surveys, which both have similar (approx. 1 min) resolution to the IRAS atlas, provides a powerful tool for studying the interstellar medium, star formation, and large-scale structure in our Galaxy. This paper documents the production and characteristics of the atlas.

  9. A high resolution β-detector

    International Nuclear Information System (INIS)

    Charon, Y.; Cuzon, J.C.; Tricoire, H.; Valentin, L.

    1987-01-01

    We present a detector which associates a charge coupled device to a light amplifier. This image sensor must detect weak β-activity, with a 10 μm resolution and should replace the autoradiographic films used for molecular hybridization. The best results are obtained with the 35 S emittor, for which the resolution and the efficiency are respectively 20 μm and 100% (relative to the measured standard source)

  10. Mechanically flexible optically transparent silicon fabric with high thermal budget devices from bulk silicon (100)

    KAUST Repository

    Hussain, Muhammad Mustafa

    2013-05-30

    Today’s information age is driven by silicon based electronics. For nearly four decades semiconductor industry has perfected the fabrication process of continuingly scaled transistor – heart of modern day electronics. In future, silicon industry will be more pervasive, whose application will range from ultra-mobile computation to bio-integrated medical electronics. Emergence of flexible electronics opens up interesting opportunities to expand the horizon of electronics industry. However, silicon – industry’s darling material is rigid and brittle. Therefore, we report a generic batch fabrication process to convert nearly any silicon electronics into a flexible one without compromising its (i) performance; (ii) ultra-large-scale-integration complexity to integrate billions of transistors within small areas; (iii) state-of-the-art process compatibility, (iv) advanced materials used in modern semiconductor technology; (v) the most widely used and well-studied low-cost substrate mono-crystalline bulk silicon (100). In our process, we make trenches using anisotropic reactive ion etching (RIE) in the inactive areas (in between the devices) of a silicon substrate (after the devices have been fabricated following the regular CMOS process), followed by a dielectric based spacer formation to protect the sidewall of the trench and then performing an isotropic etch to create caves in silicon. When these caves meet with each other the top portion of the silicon with the devices is ready to be peeled off from the bottom silicon substrate. Release process does not need to use any external support. Released silicon fabric (25 μm thick) is mechanically flexible (5 mm bending radius) and the trenches make it semi-transparent (transparency of 7%). © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  11. Silicon nanowire based high brightness, pulsed relativistic electron source

    Directory of Open Access Journals (Sweden)

    Deep Sarkar

    2017-06-01

    Full Text Available We demonstrate that silicon nanowire arrays efficiently emit relativistic electron pulses under irradiation by a high-intensity, femtosecond, and near-infrared laser (∼1018 W/cm2, 25 fs, 800 nm. The nanowire array yields fluxes and charge per bunch that are 40 times higher than those emitted by an optically flat surface, in the energy range of 0.2–0.5 MeV. The flux and charge yields for the nanowires are observed to be directional in nature unlike that for planar silicon. Particle-in-cell simulations establish that such large emission is caused by the enhancement of the local electric fields around a nanowire, which consequently leads to an enhanced absorption of laser energy. We show that the high-intensity contrast (ratio of picosecond pedestal to femtosecond peak of the laser pulse (10−9 is crucial to this large yield. We extend the notion of surface local-field enhancement, normally invoked in low-order nonlinear optical processes like second harmonic generation, optical limiting, etc., to ultrahigh laser intensities. These electron pulses, expectedly femtosecond in duration, have potential application in imaging, material modification, ultrafast dynamics, terahertz generation, and fast ion sources.

  12. Cavity cooling of free silicon nanoparticles in high vacuum.

    Science.gov (United States)

    Asenbaum, Peter; Kuhn, Stefan; Nimmrichter, Stefan; Sezer, Ugur; Arndt, Markus

    2013-01-01

    Laser cooling has given a boost to atomic physics throughout the last 30 years, as it allows one to prepare atoms in motional states, which can only be described by quantum mechanics. Most methods rely, however, on a near-resonant and cyclic coupling between laser light and well-defined internal states, which has remained a challenge for mesoscopic particles. An external cavity may compensate for the lack of internal cycling transitions in dielectric objects and it may provide assistance in the cooling of their centre-of-mass state. Here we demonstrate cavity cooling of the transverse kinetic energy of silicon nanoparticles freely propagating in high vacuum (<10(-8) mbar). We create and launch them with longitudinal velocities down to v≤1 m s(-1) using laser-induced ablation of a pristine silicon wafer. Their interaction with the light of a high-finesse infrared cavity reduces their transverse kinetic energy by up to a factor of 30.

  13. Simulation of silicon nanoparticles stabilized by hydrogen at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Galashev, Alexander Y., E-mail: galashev@ecko.uran.r [Russian Academy of Sciences, Ural Division, Institute of Industrial Ecology (Russian Federation)

    2010-10-15

    The stability of different silicon nanoparticles are investigated at a high temperature. The temperature dependence of the physicochemical properties of 60- and 73-atom silicon nanoparticles are investigated using the molecular dynamics method. The 73-atom particles have a crystal structure, a random atomic packing, and a packing formed by inserting a 13-atom icosahedron into a 60-atom fullerene. They are surrounded by a 'coat' from 60 atoms of hydrogen. The nanoassembled particle at the presence of a hydrogen 'coat' has the most stable number (close to four) of Si-Si bonds per atom. The structure and kinetic properties of a hollow single-layer fullerene-structured Si{sub 60} cluster are considered in the temperature range 10 K {<=} T {<=} 1760 K. Five series of calculations are conducted, with a simulation of several media inside and outside the Si{sub 60} cluster, specifically, the vacuum and interior spaces filled with 30 and 60 hydrogen atoms with and without the exterior hydrogen environment of 60 atoms. Fullerene surrounded by a hydrogen 'coat' and containing 60 hydrogen atoms in the interior space has a higher stability. Such cluster has smaller self-diffusion coefficients at high temperatures. The fullerene stabilized with hydrogen is stable to the formation of linear atomic chains up to the temperatures 270-280 K.

  14. High mechanical Q-factor measurements on silicon bulk samples

    Energy Technology Data Exchange (ETDEWEB)

    Nawrodt, R; Zimmer, A; Koettig, T; Schwarz, C; Heinert, D; Hudl, M; Neubert, R; Thuerk, M; Nietzsche, S; Vodel, W; Seidel, P [Friedrich-Schiller-Universitaet, Institut fuer Festkoerperphysik, Helmholtzweg 5, D-07743 Jena (Germany); Tuennermann, A [Friedrich-Schiller-Universitaet, Institut fuer Angewandte Physik, Max-Wien-Platz 1, D-07743 Jena (Germany)], E-mail: ronny.nawrodt@uni-jena.de

    2008-07-15

    Future gravitational wave detectors will be limited by different kinds of noise. Thermal noise from the coatings and the substrate material will be a serious noise contribution within the detection band of these detectors. Cooling and the use of a high mechanical Q-factor material as a substrate material will reduce the thermal noise contribution from the substrates. Silicon is one of the most interesting materials for a third generation cryogenic detector. Due to the fact that the coefficient of thermal expansion vanishes at 18 and 125 K the thermoelastic contribution to the thermal noise will disappear. We present a systematic analysis of the mechanical Q-factor at low temperatures between 5 and 300 K on bulk silicon (100) samples which are boron doped. The thickness of the cylindrical samples is varied between 6, 12, 24, and 75mm with a constant diameter of 3 inches. For the 75mm substrate a comparison between the (100) and the (111) orientation is presented. In order to obtain the mechanical Q-factor a ring-down measurement is performed. Thus, the substrate is excited to resonant vibrations by means of an electrostatic driving plate and the subsequent ring-down is recorded using a Michelson-like interferometer. The substrate itself is suspended as a pendulum by means of a tungsten wire loop. All measurements are carried out in a special cryostat which provides a temperature stability of better than 0.1K between 5 and 300K during the experiment. The influence of the suspension on the measurements is experimentally investigated and discussed. At 5.8K a highest Q-factor of 4.5 x 10{sup 8} was achieved for the 14.9 kHz mode of a silicon (100) substrate with a diameter of 3 inches and a thickness of 12 mm.

  15. High rate particle tracking and ultra-fast timing with a thin hybrid silicon pixel detector

    Science.gov (United States)

    Fiorini, M.; Aglieri Rinella, G.; Carassiti, V.; Ceccucci, A.; Cortina Gil, E.; Cotta Ramusino, A.; Dellacasa, G.; Garbolino, S.; Jarron, P.; Kaplon, J.; Kluge, A.; Marchetto, F.; Mapelli, A.; Martin, E.; Mazza, G.; Morel, M.; Noy, M.; Nuessle, G.; Perktold, L.; Petagna, P.; Petrucci, F.; Poltorak, K.; Riedler, P.; Rivetti, A.; Statera, M.; Velghe, B.

    2013-08-01

    The Gigatracker (GTK) is a hybrid silicon pixel detector designed for the NA62 experiment at CERN. The beam spectrometer, made of three GTK stations, has to sustain high and non-uniform particle rate (∼ 1 GHz in total) and measure momentum and angles of each beam track with a combined time resolution of 150 ps. In order to reduce multiple scattering and hadronic interactions of beam particles, the material budget of a single GTK station has been fixed to 0.5% X0. The expected fluence for 100 days of running is 2 ×1014 1 MeV neq /cm2, comparable to the one foreseen in the inner trackers of LHC detectors during 10 years of operation. To comply with these requirements, an efficient and very low-mass (< 0.15 %X0) cooling system is being constructed, using a novel microchannel cooling silicon plate. Two complementary read-out architectures have been produced as small-scale prototypes: one is based on a Time-over-Threshold circuit followed by a TDC shared by a group of pixels, while the other makes use of a constant-fraction discriminator followed by an on-pixel TDC. The read-out ASICs are produced in 130 nm IBM CMOS technology and will be thinned down to 100 μm or less. An overview of the Gigatracker detector system will be presented. Experimental results from laboratory and beam tests of prototype bump-bonded assemblies will be described as well. These results show a time resolution of about 170 ps for single hits from minimum ionizing particles, using 200 μm thick silicon sensors.

  16. Denuded zone in Czochralski silicon wafer with high carbon content

    International Nuclear Information System (INIS)

    Chen Jiahe; Yang Deren; Ma Xiangyang; Que Duanlin

    2006-01-01

    The thermal stability of the denuded zone (DZ) created by high-low-high-temperature annealing in high carbon content (H[C]) and low carbon content (L[C]) Czochralski silicon (Cz-Si) has been investigated in a subsequent ramping and isothermal 1050 deg. C annealing. The tiny oxygen precipitates which might occur in the DZ were checked. It was found in the L[C] Cz-Si that the DZ shrank and the density of bulk micro-defects (BMDs) reduced with the increase of time spent at 1050 deg. C. Also, the DZs above 15 μm of thickness present in the H[C] Cz-Si wafers continuously and the density and total volume of BMDs first decreased then increased and finally decreased again during the treatments. Moreover, tiny oxygen precipitates were hardly generated inside the DZs, indicating that H[C] Cz-Si wafers could support the fabrication of integrated circuits

  17. Denuded zone in Czochralski silicon wafer with high carbon content

    Science.gov (United States)

    Chen, Jiahe; Yang, Deren; Ma, Xiangyang; Que, Duanlin

    2006-12-01

    The thermal stability of the denuded zone (DZ) created by high-low-high-temperature annealing in high carbon content (H[C]) and low carbon content (L[C]) Czochralski silicon (Cz-Si) has been investigated in a subsequent ramping and isothermal 1050 °C annealing. The tiny oxygen precipitates which might occur in the DZ were checked. It was found in the L[C] Cz-Si that the DZ shrank and the density of bulk micro-defects (BMDs) reduced with the increase of time spent at 1050 °C. Also, the DZs above 15 µm of thickness present in the H[C] Cz-Si wafers continuously and the density and total volume of BMDs first decreased then increased and finally decreased again during the treatments. Moreover, tiny oxygen precipitates were hardly generated inside the DZs, indicating that H[C] Cz-Si wafers could support the fabrication of integrated circuits.

  18. High-resolution, label-free imaging of living cells with direct electron-beam-excitation-assisted optical microscopy.

    Science.gov (United States)

    Nawa, Yasunori; Inami, Wataru; Lin, Sheng; Kawata, Yoshimasa; Terakawa, Susumu

    2015-06-01

    High spatial resolution microscope is desired for deep understanding of cellular functions, in order to develop medical technologies. We demonstrate high-resolution imaging of un-labelled organelles in living cells, in which live cells on a 50 nm thick silicon nitride membrane are imaged by autofluorescence excited with a focused electron beam through the membrane. Electron beam excitation enables ultrahigh spatial resolution imaging of organelles, such as mitochondria, nuclei, and various granules. Since the autofluorescence spectra represent molecular species, this microscopy allows fast and detailed investigations of cellular status in living cells.

  19. Single sensor processing to obtain high resolution color component signals

    Science.gov (United States)

    Glenn, William E. (Inventor)

    2010-01-01

    A method for generating color video signals representative of color images of a scene includes the following steps: focusing light from the scene on an electronic image sensor via a filter having a tri-color filter pattern; producing, from outputs of the sensor, first and second relatively low resolution luminance signals; producing, from outputs of the sensor, a relatively high resolution luminance signal; producing, from a ratio of the relatively high resolution luminance signal to the first relatively low resolution luminance signal, a high band luminance component signal; producing, from outputs of the sensor, relatively low resolution color component signals; and combining each of the relatively low resolution color component signals with the high band luminance component signal to obtain relatively high resolution color component signals.

  20. Super-Resolution Reconstruction of High-Resolution Satellite ZY-3 TLC Images

    Science.gov (United States)

    Li, Lin; Wang, Wei; Luo, Heng; Ying, Shen

    2017-01-01

    Super-resolution (SR) image reconstruction is a technique used to recover a high-resolution image using the cumulative information provided by several low-resolution images. With the help of SR techniques, satellite remotely sensed images can be combined to achieve a higher-resolution image, which is especially useful for a two- or three-line camera satellite, e.g., the ZY-3 high-resolution Three Line Camera (TLC) satellite. In this paper, we introduce the application of the SR reconstruction method, including motion estimation and the robust super-resolution technique, to ZY-3 TLC images. The results show that SR reconstruction can significantly improve both the resolution and image quality of ZY-3 TLC images. PMID:28481287

  1. Super-Resolution Reconstruction of High-Resolution Satellite ZY-3 TLC Images

    Directory of Open Access Journals (Sweden)

    Lin Li

    2017-05-01

    Full Text Available Super-resolution (SR image reconstruction is a technique used to recover a high-resolution image using the cumulative information provided by several low-resolution images. With the help of SR techniques, satellite remotely sensed images can be combined to achieve a higher-resolution image, which is especially useful for a two- or three-line camera satellite, e.g., the ZY-3 high-resolution Three Line Camera (TLC satellite. In this paper, we introduce the application of the SR reconstruction method, including motion estimation and the robust super-resolution technique, to ZY-3 TLC images. The results show that SR reconstruction can significantly improve both the resolution and image quality of ZY-3 TLC images.

  2. Super-Resolution Reconstruction of High-Resolution Satellite ZY-3 TLC Images.

    Science.gov (United States)

    Li, Lin; Wang, Wei; Luo, Heng; Ying, Shen

    2017-05-07

    Super-resolution (SR) image reconstruction is a technique used to recover a high-resolution image using the cumulative information provided by several low-resolution images. With the help of SR techniques, satellite remotely sensed images can be combined to achieve a higher-resolution image, which is especially useful for a two- or three-line camera satellite, e.g., the ZY-3 high-resolution Three Line Camera (TLC) satellite. In this paper, we introduce the application of the SR reconstruction method, including motion estimation and the robust super-resolution technique, to ZY-3 TLC images. The results show that SR reconstruction can significantly improve both the resolution and image quality of ZY-3 TLC images.

  3. SHARC: Silicon Highly-segmented Array for Reactions and Coulex used in conjunction with the TIGRESS γ-ray spectrometer

    Science.gov (United States)

    Diget, C. Aa; Fox, S. P.; Smith, A.; Williams, S.; Porter-Peden, M.; Achouri, L.; Adsley, P.; Al-Falou, H.; Austin, R. A. E.; Ball, G. C.; Blackmon, J. C.; Brown, S.; Catford, W. N.; Chen, A. A.; Chen, J.; Churchman, R. M.; Dech, J.; DiValenti, D.; Djongolov, M.; Fulton, B. R.; Garnsworthy, A.; Hackman, G.; Hager, U.; Kshetri, R.; Kurchaninov, L.; Laird, A. M.; Martin, J.-P.; Matos, M.; Orce, J. N.; Orr, N. A.; Pearson, C. J.; Ruiz, C.; Sarazin, F.; Sjue, S.; Smalley, D.; Svensson, C. E.; Taggart, M.; Tardiff, E.; Wilson, G. L.

    2011-02-01

    The combination of γ-ray spectroscopy and charged-particle spectroscopy is a powerful tool for the study of nuclear reactions with beams of nuclei far from stability. This paper presents a new silicon detector array, SHARC, the Silicon Highly-segmented Array for Reactions and Coulex. The array is used at the radioactive-ion-beam facility at TRIUMF (Canada), in conjunction with the TIGRESS γ-ray spectrometer, and is built from custom Si-strip detectors utilising a fully digital readout. SHARC has more than 50% efficiency, approximately 1000-strip segmentation, angular resolutions of Δθ approx 1.3 deg and Δphi approx 3.5 deg, 25-30 keV energy resolution, and thresholds of 200 keV for up to 25 MeV particles. SHARC is now complete, and the experimental program in nuclear astrophysics and nuclear structure has commenced.

  4. SHARC: Silicon Highly-segmented Array for Reactions and Coulex used in conjunction with the TIGRESS {gamma}-ray spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Diget, C A; Fox, S P; Adsley, P; Fulton, B R [Department of Physics, University of York, York, YO10 5DD (United Kingdom); Smith, A [School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL (United Kingdom); Williams, S; Ball, G C; Churchman, R M; Dech, J; Valentino, D Di; Djongolov, M [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Porter-Peden, M [Department of Physics, Colorado School of Mines, Golden, CO 80401 (United States); Achouri, L [Laboratoire de Physique Corpusculaire, IN2P3-CNRS, ISMRA et Universite de Caen, F-14050 Caen (France); Al-Falou, H; Austin, R A E [Department of Astronomy and Physics, Saint Mary' s University, Halifax, NS, B3H 3C3 (Canada); Blackmon, J C [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Brown, S; Catford, W N [Department of Physics, University of Surrey, Guildford, GU2 5XH (United Kingdom); Chen, A A; Chen, J, E-mail: christian.diget@york.ac.uk [Department of Physics and Astronomy, McMaster University, Hamilton, ON, L8S 4M1 (Canada)

    2011-02-01

    The combination of {gamma}-ray spectroscopy and charged-particle spectroscopy is a powerful tool for the study of nuclear reactions with beams of nuclei far from stability. This paper presents a new silicon detector array, SHARC, the Silicon Highly-segmented Array for Reactions and Coulex. The array is used at the radioactive-ion-beam facility at TRIUMF (Canada), in conjunction with the TIGRESS {gamma}-ray spectrometer, and is built from custom Si-strip detectors utilising a fully digital readout. SHARC has more than 50% efficiency, approximately 1000-strip segmentation, angular resolutions of {Delta}{theta} {approx} 1.3 deg. and {Delta}{phi} {approx} 3.5 deg., 25-30 keV energy resolution, and thresholds of 200 keV for up to 25 MeV particles. SHARC is now complete, and the experimental program in nuclear astrophysics and nuclear structure has commenced.

  5. SHARC: Silicon Highly-segmented Array for Reactions and Coulex used in conjunction with the TIGRESS γ-ray spectrometer

    International Nuclear Information System (INIS)

    Diget, C A; Fox, S P; Adsley, P; Fulton, B R; Smith, A; Williams, S; Ball, G C; Churchman, R M; Dech, J; Valentino, D Di; Djongolov, M; Porter-Peden, M; Achouri, L; Al-Falou, H; Austin, R A E; Blackmon, J C; Brown, S; Catford, W N; Chen, A A; Chen, J

    2011-01-01

    The combination of γ-ray spectroscopy and charged-particle spectroscopy is a powerful tool for the study of nuclear reactions with beams of nuclei far from stability. This paper presents a new silicon detector array, SHARC, the Silicon Highly-segmented Array for Reactions and Coulex. The array is used at the radioactive-ion-beam facility at TRIUMF (Canada), in conjunction with the TIGRESS γ-ray spectrometer, and is built from custom Si-strip detectors utilising a fully digital readout. SHARC has more than 50% efficiency, approximately 1000-strip segmentation, angular resolutions of Δθ ∼ 1.3 deg. and Δφ ∼ 3.5 deg., 25-30 keV energy resolution, and thresholds of 200 keV for up to 25 MeV particles. SHARC is now complete, and the experimental program in nuclear astrophysics and nuclear structure has commenced.

  6. Silicon Transporters and Effects of Silicon Amendments in Strawberry under High Tunnel and Field Conditions

    Directory of Open Access Journals (Sweden)

    Samuel Ouellette

    2017-06-01

    Full Text Available Together with longer production periods, the commercial transition to day-neutral strawberry (Fragaria × ananassa varieties has favored the development of diseases such as powdery mildew (Podosphaera aphanis that thrives in late summer-early fall. In an attempt to find alternative solutions to fungicides currently employed to curb the disease, we wanted to investigate the potential of silicon (Si amendments that have been associated with prophylactic properties against powdery mildews. To this end, our first objective was to determine if strawberry was a Si-competent species following the recent characterization of the properties of Si transporters that plants must carry to uptake silicic acid. Based on genomic data, we were able to conclude that strawberry contained both functional influx (Lsi1 and efflux (Lsi2 transporters for Si uptake. Subsequently commercial experiments under high tunnel and field conditions were conducted with different Si fertilization regimes: constant soluble Si feeding in high tunnel, and bi-weekly soluble Si feeding or three concentrations of calcium silicate fertilization in the field. Results from high tunnel experiments showed that strawberry could accumulate as much as 3% Si on a dry-weight basis, the highest concentration ever reported for this species. All six tested cultivars contained roughly the same concentration, thereby confirming the limited genetic variability, also observed in other species, associated with the trait. Silicon fertilization under high tunnel led to a significant reduction of powdery mildew severity in both years and on all cultivars, and a significant increase in yield of marketable fruits reaching as much as 300% with cv. Monterey. By contrast, Si fertilization under field conditions in soils deficient in plant available Si, either in soluble or solid form, did not result in significant accumulation of Si in plants, regardless of the cultivars, year or concentrations. Our results have

  7. High resolution CT findings of pseudoalveolar sarcoidosis

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Ji Eun; Park, Jun Gyun; Choe, Kyu Ok; Kim, Sang Jin [Yonsei University College of Medicine, Seoul (Korea, Republic of); Ryu, Young Hoon; Im, Jung Gi [Seoul National University College of Medicine, Seoul (Korea, Republic of); Lee, Kyoung Soo [Sungkunkwan University College of Medicine, Seoul (Korea, Republic of); Song, Koun Sik [University of Ulsan College of Medicine, Seoul (Korea, Republic of); Kim, Hyae Young [National Cancer Centar, Seoul (Korea, Republic of)

    2002-08-01

    To determine the specific high-resolution CT features of sarcoidosis in which the observed pattern is predominantly pseudoalveolar. We retrospectively reviewed the HRCT findings in 15 cases in which chest radiography demonstrated pseudoalveolar consolidation. In all 15, sarcoidosis was pathologically proven. The distribution and characterization of the following CT features was meticulously scrutinized: distribution and characterization of pseudoalveolar lesions, air-bronchograms, micronodules, thickening of bronchovascular bundles and interlobular septa, lung distortion, ground-glass opacities and combined hilar and mediastinal lymphadenopathy. Follow-up CT scans were available in three cases after corticosteroid administration. Between one and 12 (mean, 5.6) pseudoalveolar lesions appeared as dense homogeneous or inhomogeneous opacities 1-4.5 cm in diameter and with an irregular margin located either at the lung periphery adjacent to the pleural surface or along the bronchovascular bundles, with mainly bilateral distribution (n=14, 93%). An air-bronchogram was observed in ten cases. Micronodules were observed at the periphery of the lesion or surrounding lung, which along with a thickened bronchovascular bundle was a consistent feature in all cases. Additional CT features included hilar and mediastinal lymphadenopathy (n=14, 93%), thickened interlobular septa (n=12, 80%), and ground-glass opacity (n=10, 67%). Lung distortion was noted in only one case (7%). After steroid administration pseudoalveolar lesions decreased in number and size in all three cases in which follow-up CT was available. The consistent HRCT features of pseudoalveolar sarcoidosis are bilateral multifocal dense homogenous or inhomogenous opacity and an irregular margin located either at the lung periphery adjacent to the pleural surface or along the bronchovascular bundles. Micronodules are present at the periphery of the lesion or surrounding lung. The features are reversible administration.

  8. High time-resolution sprite observations

    Science.gov (United States)

    Stenbaek-Nielsen, H. C.; McHarg, G. G.

    2007-12-01

    Imaging sprites at 10,000 fps have revealed new details about their temporal development. TV observations show a highly structured central body with downward tendrils and upward branches. But rather than being leaders, as suggested by the long streaks in the TV recordings, tendrils and branches are actually formed by spatially compact streamer heads moving at velocities up to 0.3 c. In an individual sprite event the downward moving streamer heads start first forming the tendrils; later, and from a lower altitude and from existing luminous sprite structures, upward moving streamer heads may appear to form the branches. If there are no upward moving streamer heads the event would be classified as a C-sprite, otherwise it would be a carrot sprite. Following the streamer head activity we see afterglow in which little or no temporal and spatial activity is present. The streamer heads are very bright and they appear to be point sources, i.e. their spatial dimensions are less than our 100-200 m image resolution. Streamer head modeling indicates a scale size of ~25 m in which case the brightness would be in the range 1-100 GR. Other models predict volume emission rates leading to a streamer head spatial scale size in the 10 to 100 m range. Our observations conclusively show the downward and upward propagating streamer heads to be separated in time and space. This is in contrast to a number of models in which both down and up going streamer heads emanates from the origin of the process. We frequently see old sprites re-appear in response to new activity suggesting that sprite activity leaves some imprint on the background atmosphere. Given the very large brightness of the streamer heads it would not be surprising if sprite activity initiates chemical processes that could locally affect the composition of the atmosphere, but whether this affects the mesosphere on a larger scale remains uncertain.

  9. High spectral resolution studies of gamma ray bursts on new missions

    International Nuclear Information System (INIS)

    Desai, U. D.; Acuna, M. H.; Cline, T. L.; Dennis, B. R.; Orwig, L. E.; Trombka, J. I.; Starr, R. D.

    1996-01-01

    Two new missions will be launched in 1996 and 1997, each carrying X-ray and gamma ray detectors capable of high spectral resolution at room temperature. The Argentine Satelite de Aplicaciones Cientificas (SAC-B) and the Small Spacecraft Technology Initiative (SSTI) Clark missions will each carry several arrays of X-ray detectors primarily intended for the study of solar flares and gamma-ray bursts. Arrays of small (1 cm 2 ) cadmium zinc telluride (CZT) units will provide x-ray measurements in the 10 to 80 keV range with an energy resolution of ≅6 keV. Arrays of both silicon avalanche photodiodes (APD) and P-intrinsic-N (PIN) photodiodes (for the SAC-B mission only) will provide energy coverage from 2-25 keV with ≅1 keV resolution. For SAC-B, higher energy spectral data covering the 30-300 keV energy range will be provided by CsI(Tl) scintillators coupled to silicon APDs, resulting in similar resolution but greater simplicity relative to conventional CsI/PMT systems. Because of problems with the Pegasus launch vehicle, the launch of SAC-B has been delayed until 1997. The launch of the SSTI Clark mission is scheduled for June 1996

  10. High-resolution calorimetry: limitations of doped semiconductor thermometers

    CERN Document Server

    McCammon, D; Apodaca, E; Deiker, S; Galeazzi, M; Han, S I; Lesser, A; Sanders, W; Kelley, R L; Moseley, S H; Porter, F S; Stahle, C K; Szymkowiak, A E

    1999-01-01

    Small thermal calorimeters operating at cryogenic temperatures have achieved an energy resolution for single X-ray photons that is a factor of 20 better than the theoretical limit for a silicon ionization detector. To determine the potential for further improvements and decide on likely routes for achieving them, we discuss detector design optimization, first for an ideal calorimeter, and then for the case where components exhibit non-ideal behavior. Two serious non-ideal properties of doped semiconductor thermometers are electron-phonon decoupling and excess noise. These have been characterized over a range of sensitivity and operating temperature, and their effects on design optimization and ultimate performance can be evaluated.

  11. High Resolution Observations using Adaptive Optics: Achievements ...

    Indian Academy of Sciences (India)

    Hence, modern telescopes thrive on improving the spatial, spectral, and temporal resolutions using an AO system. It may be stated that most of the recent large solar. †NSO is operated by the Association of Universities for Research in Astronomy (AURA) under co-operative agreement with National Science Foundation ...

  12. Crystalline-Amorphous Core−Shell Silicon Nanowires for High Capacity and High Current Battery Electrodes

    KAUST Repository

    Cui, Li-Feng

    2009-01-14

    Silicon is an attractive alloy-type anode material for lithium ion batteries because of its highest known capacity (4200 mAh/g). However silicon\\'s large volume change upon lithium insertion and extraction, which causes pulverization and capacity fading, has limited its applications. Designing nanoscale hierarchical structures is a novel approach to address the issues associated with the large volume changes. In this letter, we introduce a core-shell design of silicon nanowires for highpower and long-life lithium battery electrodes. Silicon crystalline- amorphous core-shell nanowires were grown directly on stainless steel current collectors by a simple one-step synthesis. Amorphous Si shells instead of crystalline Si cores can be selected to be electrochemically active due to the difference of their lithiation potentials. Therefore, crystalline Si cores function as a stable mechanical support and an efficient electrical conducting pathway while amorphous shells store Li ions. We demonstrate here that these core-shell nanowires have high charge storage capacity (̃1000 mAh/g, 3 times of carbon) with ̃90% capacity retention over 100 cycles. They also show excellent electrochemical performance at high rate charging and discharging (6.8 A/g, ̃20 times of carbon at 1 h rate). © 2009 American Chemical Society.

  13. High Spatial Resolution Bidirectional Reflectance Retrieval Using Satellite Data

    Science.gov (United States)

    2010-12-01

    done on South African savanna vegetation, researchers found that a leaf, when intact displayed specular reflection, but when crushed more closely... community , low spatial resolution is defined as 30 m or greater, medium ranges from 4-30 m, and high resolution imagery is less than 4 m. Excellent...not require a high temporal resolution, as change occurs over a long period of time, whereas the intelligence community requires high temporal

  14. High resolution time integration for Sn radiation transport

    International Nuclear Information System (INIS)

    Thoreson, Greg; McClarren, Ryan G.; Chang, Jae H.

    2008-01-01

    First order, second order and high resolution time discretization schemes are implemented and studied for the S n equations. The high resolution method employs a rate of convergence better than first order, but also suppresses artificial oscillations introduced by second order schemes in hyperbolic differential equations. All three methods were compared for accuracy and convergence rates. For non-absorbing problems, both second order and high resolution converged to the same solution as the first order with better convergence rates. High resolution is more accurate than first order and matches or exceeds the second order method. (authors)

  15. Method of Assembling a Silicon Carbide High Temperature Anemometer

    Science.gov (United States)

    Okojie, Robert S. (Inventor); Fralick, Gustave C. (Inventor); Saad, George J. (Inventor)

    2004-01-01

    A high temperature anemometer includes a pair of substrates. One of the substrates has a plurality of electrodes on a facing surface, while the other of the substrates has a sensor cavity on a facing surface. A sensor is received in the sensor cavity, wherein the sensor has a plurality of bondpads, and wherein the bondpads contact the plurality of electrodes when the facing surfaces are mated with one another. The anemometer further includes a plurality of plug-in pins, wherein the substrate with the cavity has a plurality of trenches with each one receiving a plurality of plug-in pins. The plurality of plug-in pins contact the plurality of electrodes when the substrates are mated with one another. The sensor cavity is at an end of one of the substrates such that the sensor partially extends from the substrate. The sensor and the substrates are preferably made of silicon carbide.

  16. EMODnet High Resolution Seabed Mapping - further developing a high resolution digital bathymetry for European seas

    Science.gov (United States)

    Schaap, D.; Schmitt, T.

    2017-12-01

    Access to marine data is a key issue for the EU Marine Strategy Framework Directive and the EU Marine Knowledge 2020 agenda and includes the European Marine Observation and Data Network (EMODnet) initiative. EMODnet aims at assembling European marine data, data products and metadata from diverse sources in a uniform way. The EMODnet Bathymetry project has developed Digital Terrain Models (DTM) for the European seas. These have been produced from survey and aggregated data sets that are indexed with metadata by adopting the SeaDataNet Catalogue services. SeaDataNet is a network of major oceanographic data centres around the European seas that manage, operate and further develop a pan-European infrastructure for marine and ocean data management. The latest EMODnet Bathymetry DTM release has a grid resolution of 1/8 arcminute and covers all European sea regions. Use has been made of circa 7800 gathered survey datasets and composite DTMs. Catalogues and the EMODnet DTM are published at the dedicated EMODnet Bathymetry portal including a versatile DTM viewing and downloading service. End December 2016 the Bathymetry project has been succeeded by EMODnet High Resolution Seabed Mapping (HRSM). This continues gathering of bathymetric in-situ data sets with extra efforts for near coastal waters and coastal zones. In addition Satellite Derived Bathymetry data are included to fill gaps in coverage of the coastal zones. The extra data and composite DTMs will increase the coverage of the European seas and its coastlines, and provide input for producing an EMODnet DTM with a common resolution of 1/16 arc minutes. The Bathymetry Viewing and Download service will be upgraded to provide a multi-resolution map and including 3D viewing. The higher resolution DTMs will also be used to determine best-estimates of the European coastline for a range of tidal levels (HAT, MHW, MSL, Chart Datum, LAT), thereby making use of a tidal model for Europe. Extra challenges will be `moving to the

  17. The high resolution spaghetti hadron calorimeter

    International Nuclear Information System (INIS)

    Jenni, P.; Sonderegger, P.; Paar, H.P.; Wigmans, R.

    1987-01-01

    It is proposed to build a prototype for a hadron calorimeter with scintillating plastic fibres as active material. The absorber material is lead. Provided that these components are used in the appropriate volume ratio, excellent performance may be expected, e.g. an energy resolution of 30%/√E for jet detection. The proposed design offers additional advantages compared to the classical sandwich calorimeter structures in terms of granularity, hermiticity, uniformity, compactness, readout, radiation resistivity, stability and calibration. 22 refs.; 7 figs

  18. High resolution spectroscopy of atomic hydrogen

    International Nuclear Information System (INIS)

    Ferguson, A.I.; Goldsmith, J.E.M.; Haensch, T.W.; Weber, E.W.

    1979-01-01

    During the past years, new studies of the Balmer-α line have been completed at Stanford, which take advantage of recent developments in instrumentation and coherent light techniques to achieve much improved resolution and accuracy. The effects of pressure shift and pressure broadening are investigated. One of the most intrigueing transitions to be studied in atomic hydrogen is the two-photon transition from the 1S ground state to the metastable 2S state. Experimental methods are discussed. (KBE)

  19. High resolution, monochromatic x-ray topography capability at CHESS

    Energy Technology Data Exchange (ETDEWEB)

    Finkelstein, K. D., E-mail: kdf1@cornell.edu; Pauling, A.; Brown, Z. [CHESS, Cornell University, Ithaca, NY (United States); Jones, R. [Department of Physics, University of Connecticut, Storrs, CT (United States); Tarun, A.; Misra, D. S. [IIa Technologies (Singapore); Jupitz, S. [St. Mary’s College of Maryland, St. Mary’s City, MD (United States); Sagan, D. C. [CLASSE, Cornell University, Ithaca, NY (United States)

    2016-07-27

    CHESS has a monochromatic x-ray topography capability serving continually expanding user interest. The setup consists of a beam expanding monochromator, 6-circle diffactometer, and CHESS designed CMOS camera with real time sample-alignment capability. This provides rocking curve mapping with angle resolution as small as 2 µradians, spatial resolution to 3 microns, and field of view up to 7mm. Thus far the capability has been applied for: improving CVD-diamond growth, evaluating perfection of ultra-thin diamond membranes, correlating performance of diamond-based electronics with crystal defect structure, and defect analysis of single crystal silicon carbide. This paper describes our topography system, explains its capabilities, and presents experimental results from several applications.

  20. High resolution, monochromatic x-ray topography capability at CHESS

    International Nuclear Information System (INIS)

    Finkelstein, K. D.; Pauling, A.; Brown, Z.; Jones, R.; Tarun, A.; Misra, D. S.; Jupitz, S.; Sagan, D. C.

    2016-01-01

    CHESS has a monochromatic x-ray topography capability serving continually expanding user interest. The setup consists of a beam expanding monochromator, 6-circle diffactometer, and CHESS designed CMOS camera with real time sample-alignment capability. This provides rocking curve mapping with angle resolution as small as 2 µradians, spatial resolution to 3 microns, and field of view up to 7mm. Thus far the capability has been applied for: improving CVD-diamond growth, evaluating perfection of ultra-thin diamond membranes, correlating performance of diamond-based electronics with crystal defect structure, and defect analysis of single crystal silicon carbide. This paper describes our topography system, explains its capabilities, and presents experimental results from several applications.

  1. Fabrication and Characterisation of Silicon Waveguides for High-Speed Optical Signal Processing

    DEFF Research Database (Denmark)

    Jensen, Asger Sellerup

    This Ph.D. thesis treats various aspects of silicon photonics. From the limitations of silicon as a linear and nonlinear waveguide medium to its synergy with other waveguide materials. Various methods for reducing sidewall roughness and line edge roughness of silicon waveguides are attempted...... was too high for any practical applications. It is speculated that the attempt at creating a material with low density of dangling bonds was unsuccessful. Nevertheless, linear losses of 2.4dB/cm at 1550nm wavelength in the silicon waveguides remained sufficiently low that high speed nonlinear optical...

  2. HIGH FREQUENCY INDUCTION WELDING OF HIGH SILICON STEEL TUBES

    Directory of Open Access Journals (Sweden)

    Ricardo Miranda Alé

    2012-06-01

    Full Text Available High-Si steel is a low cost alternative for the fabrication of tubular structures resistant to atmospheric corrosion. However, the literature has often pointed out that steels presenting a higher Si content and/or a lower Mn/Si ratio have higher susceptibility to defects at the weld bond line during HFIW (High Frequency Induction Welding process, which has been widely used for manufacturing small diameter tubes. In this study the effect of the HFIW conditions on the quality of steel tubes with high-Si content and low Mn/Si ratio is investigated. The quality of welded tubes was determined by flare test and the defects in the bond line were identified by SEM. It has been found that higher welding speeds, V-convergence angles and power input should be applied in welding of high-Si steel, when compared to similar strength C-Mn steel.

  3. High-resolution DEM Effects on Geophysical Flow Models

    Science.gov (United States)

    Williams, M. R.; Bursik, M. I.; Stefanescu, R. E. R.; Patra, A. K.

    2014-12-01

    Geophysical mass flow models are numerical models that approximate pyroclastic flow events and can be used to assess the volcanic hazards certain areas may face. One such model, TITAN2D, approximates granular-flow physics based on a depth-averaged analytical model using inputs of basal and internal friction, material volume at a coordinate point, and a GIS in the form of a digital elevation model (DEM). The volume of modeled material propagates over the DEM in a way that is governed by the slope and curvature of the DEM surface and the basal and internal friction angles. Results from TITAN2D are highly dependent upon the inputs to the model. Here we focus on a single input: the DEM, which can vary in resolution. High resolution DEMs are advantageous in that they contain more surface details than lower-resolution models, presumably allowing modeled flows to propagate in a way more true to the real surface. However, very high resolution DEMs can create undesirable artifacts in the slope and curvature that corrupt flow calculations. With high-resolution DEMs becoming more widely available and preferable for use, determining the point at which high resolution data is less advantageous compared to lower resolution data becomes important. We find that in cases of high resolution, integer-valued DEMs, very high-resolution is detrimental to good model outputs when moderate-to-low (solutions for rectification of the problem.

  4. High-resolution x-ray imaging using a structured scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Hormozan, Yashar, E-mail: hormozan@kth.se; Sychugov, Ilya; Linnros, Jan [Materials and Nano Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, Kista, Stockholm SE-16440 (Sweden)

    2016-02-15

    Purpose: In this study, the authors introduce a new generation of finely structured scintillators with a very high spatial resolution (a few micrometers) compared to conventional scintillators, yet maintaining a thick absorbing layer for improved detectivity. Methods: Their concept is based on a 2D array of high aspect ratio pores which are fabricated by ICP etching, with spacings (pitches) of a few micrometers, on silicon and oxidation of the pore walls. The pores were subsequently filled by melting of powdered CsI(Tl), as the scintillating agent. In order to couple the secondary emitted photons of the back of the scintillator array to a CCD device, having a larger pixel size than the pore pitch, an open optical microscope with adjustable magnification was designed and implemented. By imaging a sharp edge, the authors were able to calculate the modulation transfer function (MTF) of this finely structured scintillator. Results: The x-ray images of individually resolved pores suggest that they have been almost uniformly filled, and the MTF measurements show the feasibility of a few microns spatial resolution imaging, as set by the scintillator pore size. Compared to existing techniques utilizing CsI needles as a structured scintillator, their results imply an almost sevenfold improvement in resolution. Finally, high resolution images, taken by their detector, are presented. Conclusions: The presented work successfully shows the functionality of their detector concept for high resolution imaging and further fabrication developments are most likely to result in higher quantum efficiencies.

  5. A 1024 pad silicon detector to solve tracking ambiguities in high multiplicity events

    International Nuclear Information System (INIS)

    Simone, S.; Catanesi, M.G.; Di Bari, D.; Didonna, V.; Elia, D.; Ghidini, B.; Lenti, V.; Manzari, V.; Nappi, E.

    1996-01-01

    Silicon detectors with two-dimensional pad readout have been designed and constructed for the WA97 experiment at CERN, in order to solve ambiguities for track reconstruction in a silicon microstrip telescope. A high density fanouts has been developed on a glass support to allow the electrical contacts between the detector and the front end electronics. Silicon pad detectors have been successfully operated both during the proton-Pb and Pb-Pb runs of the WA97 experiment. (orig.)

  6. Highly permeable and mechanically robust silicon carbide hollow fiber membranes

    NARCIS (Netherlands)

    de Wit, Patrick; Kappert, Emiel; Lohaus, T.; Wessling, Matthias; Nijmeijer, Arian; Benes, Nieck Edwin

    2015-01-01

    Silicon carbide (SiC) membranes have shown large potential for applications in water treatment. Being able to make these membranes in a hollow fiber geometry allows for higher surface-to-volume ratios. In this study, we present a thermal treatment procedure that is tuned to produce porous silicon

  7. Nanocrystalline silicon prepared at high growth rate using helium ...

    Indian Academy of Sciences (India)

    Wintec

    Abstract. Growth and optimization of the nanocrystalline silicon (nc-Si:H) films have been studied by varying the electrical power applied to the helium diluted silane plasma in RF glow discharge. Wide optical gap and conducting intrinsic nanocrystalline silicon network of controlled crystalline volume fraction and oriented.

  8. High resolution NMR spectroscopy of synthetic polymers in bulk

    International Nuclear Information System (INIS)

    Komorski, R.A.

    1986-01-01

    The contents of this book are: Overview of high-resolution NMR of solid polymers; High-resolution NMR of glassy amorphous polymers; Carbon-13 solid-state NMR of semicrystalline polymers; Conformational analysis of polymers of solid-state NMR; High-resolution NMR studies of oriented polymers; High-resolution solid-state NMR of protons in polymers; and Deuterium NMR of solid polymers. This work brings together the various approaches for high-resolution NMR studies of bulk polymers into one volume. Heavy emphasis is, of course, given to 13C NMR studies both above and below Tg. Standard high-power pulse and wide-line techniques are not covered

  9. High-performance lithium battery anodes using silicon nanowires.

    Science.gov (United States)

    Chan, Candace K; Peng, Hailin; Liu, Gao; McIlwrath, Kevin; Zhang, Xiao Feng; Huggins, Robert A; Cui, Yi

    2008-01-01

    There is great interest in developing rechargeable lithium batteries with higher energy capacity and longer cycle life for applications in portable electronic devices, electric vehicles and implantable medical devices. Silicon is an attractive anode material for lithium batteries because it has a low discharge potential and the highest known theoretical charge capacity (4,200 mAh g(-1); ref. 2). Although this is more than ten times higher than existing graphite anodes and much larger than various nitride and oxide materials, silicon anodes have limited applications because silicon's volume changes by 400% upon insertion and extraction of lithium which results in pulverization and capacity fading. Here, we show that silicon nanowire battery electrodes circumvent these issues as they can accommodate large strain without pulverization, provide good electronic contact and conduction, and display short lithium insertion distances. We achieved the theoretical charge capacity for silicon anodes and maintained a discharge capacity close to 75% of this maximum, with little fading during cycling.

  10. High-resolution X-ray diffraction studies of multilayers

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Hornstrup, Allan; Schnopper, H. W.

    1988-01-01

    High-resolution X-ray diffraction studies of the perfection of state-of-the-art multilayers are presented. Data were obtained using a triple-axis perfect-crystal X-ray diffractometer. Measurements reveal large-scale figure errors in the substrate. A high-resolution triple-axis set up is required...

  11. Achieving sensitive, high-resolution laser spectroscopy at CRIS

    Energy Technology Data Exchange (ETDEWEB)

    Groote, R. P. de [Instituut voor Kern- en Stralingsfysica, KU Leuven (Belgium); Lynch, K. M., E-mail: kara.marie.lynch@cern.ch [EP Department, CERN, ISOLDE (Switzerland); Wilkins, S. G. [The University of Manchester, School of Physics and Astronomy (United Kingdom); Collaboration: the CRIS collaboration

    2017-11-15

    The Collinear Resonance Ionization Spectroscopy (CRIS) experiment, located at the ISOLDE facility, has recently performed high-resolution laser spectroscopy, with linewidths down to 20 MHz. In this article, we present the modifications to the beam line and the newly-installed laser systems that have made sensitive, high-resolution measurements possible. Highlights of recent experimental campaigns are presented.

  12. Scalable Algorithms for Large High-Resolution Terrain Data

    DEFF Research Database (Denmark)

    Mølhave, Thomas; Agarwal, Pankaj K.; Arge, Lars Allan

    2010-01-01

    In this paper we demonstrate that the technology required to perform typical GIS computations on very large high-resolution terrain models has matured enough to be ready for use by practitioners. We also demonstrate the impact that high-resolution data has on common problems. To our knowledge, so...

  13. Achieving sensitive, high-resolution laser spectroscopy at CRIS

    Science.gov (United States)

    de Groote, R. P.; Lynch, K. M.; Wilkins, S. G.

    2017-11-01

    The Collinear Resonance Ionization Spectroscopy (CRIS) experiment, located at the ISOLDE facility, has recently performed high-resolution laser spectroscopy, with linewidths down to 20 MHz. In this article, we present the modifications to the beam line and the newly-installed laser systems that have made sensitive, high-resolution measurements possible. Highlights of recent experimental campaigns are presented.

  14. High-resolution X-ray Multilayers

    International Nuclear Information System (INIS)

    Martynov, V.V.; Platonov, Yu.; Kazimirov, A.; Bilderback, D.H.

    2004-01-01

    Two new approaches are taken in multilayer fabrication to help bridge the gap in bandwidth between traditional multilayers (1 to 2%) and perfect crystals (0.01%). The first approach is based on creating many layers of low-contrast Al2O3/ B4C materials. The second approach is based on using multilayer structures with a small d-spacing using traditional W/B4C and Mo/B4C materials. With 8 keV x-rays on the Chess A2 beamline, we measured a bandwidth of 0.27% with a reflectivity of 40% and a Darwin width of 17 arc seconds from a 26 A d-spacing multilayer with 800 bi-layers of Al2O3/B4C using the low-contrast approach. On the other hand, the short period approach with a W/B4C multilayer and a 14.8 A d-spacing showed a resolution of 0.5 % and a reflectivity of 58.5%. Two more Mo/B4C samples with d-spacings of 15 A and 20 A showed energy resolutions of 0.25% and 0.52% with corresponding reflectivities of 39% and 66%. Thus we observe that both methods can produce useful x-ray optical components

  15. High-Speed Smart Camera with High Resolution

    Directory of Open Access Journals (Sweden)

    J. Dubois

    2007-02-01

    Full Text Available High-speed video cameras are powerful tools for investigating for instance the biomechanics analysis or the movements of mechanical parts in manufacturing processes. In the past years, the use of CMOS sensors instead of CCDs has enabled the development of high-speed video cameras offering digital outputs, readout flexibility, and lower manufacturing costs. In this paper, we propose a high-speed smart camera based on a CMOS sensor with embedded processing. Two types of algorithms have been implemented. A compression algorithm, specific to high-speed imaging constraints, has been implemented. This implementation allows to reduce the large data flow (6.55 Gbps and to propose a transfer on a serial output link (USB 2.0. The second type of algorithm is dedicated to feature extraction such as edge detection, markers extraction, or image analysis, wavelet analysis, and object tracking. These image processing algorithms have been implemented into an FPGA embedded inside the camera. These implementations are low-cost in terms of hardware resources. This FPGA technology allows us to process in real time 500 images per second with a 1280×1024 resolution. This camera system is a reconfigurable platform, other image processing algorithms can be implemented.

  16. High-Speed Smart Camera with High Resolution

    Directory of Open Access Journals (Sweden)

    Mosqueron R

    2007-01-01

    Full Text Available High-speed video cameras are powerful tools for investigating for instance the biomechanics analysis or the movements of mechanical parts in manufacturing processes. In the past years, the use of CMOS sensors instead of CCDs has enabled the development of high-speed video cameras offering digital outputs, readout flexibility, and lower manufacturing costs. In this paper, we propose a high-speed smart camera based on a CMOS sensor with embedded processing. Two types of algorithms have been implemented. A compression algorithm, specific to high-speed imaging constraints, has been implemented. This implementation allows to reduce the large data flow (6.55 Gbps and to propose a transfer on a serial output link (USB 2.0. The second type of algorithm is dedicated to feature extraction such as edge detection, markers extraction, or image analysis, wavelet analysis, and object tracking. These image processing algorithms have been implemented into an FPGA embedded inside the camera. These implementations are low-cost in terms of hardware resources. This FPGA technology allows us to process in real time 500 images per second with a 1280×1024 resolution. This camera system is a reconfigurable platform, other image processing algorithms can be implemented.

  17. One dimension high range resolution profile of terahertz radar

    Science.gov (United States)

    Liang, Meiyan; Zeng, Bangze; Zhang, Cunlin; Zhao, Yuejin

    2012-12-01

    Step frequency signal is one of the more commonly used radar signal for high range resolution, it commonly used in radar target recognition. The wavelength of Terahertz signal is shorter than that of the microwave, so it is easy to realize the high range resolution. The paper first introduces the step frequency signal to obtain the one-dimensional distance image, and analyze the principle of high resolution range profiles of step frequency radar. Then, the 0.2THz step frequency radar systems are introduced. Finally, the high resolution range profiles are achieved by the simulation of Matlab. The simulation results show that the step frequency THz radar can reach centimeter level high resolution on stationary targets. For moving targets exist distance divergence and coupling shift. With greater speed, the greater the distortion.

  18. High-Resolution Sonars: What Resolution Do We Need for Target Recognition?

    Directory of Open Access Journals (Sweden)

    Pailhas Yan

    2010-01-01

    Full Text Available Target recognition in sonar imagery has long been an active research area in the maritime domain, especially in the mine-counter measure context. Recently it has received even more attention as new sensors with increased resolution have been developed; new threats to critical maritime assets and a new paradigm for target recognition based on autonomous platforms have emerged. With the recent introduction of Synthetic Aperture Sonar systems and high-frequency sonars, sonar resolution has dramatically increased and noise levels decreased. Sonar images are distance images but at high resolution they tend to appear visually as optical images. Traditionally algorithms have been developed specifically for imaging sonars because of their limited resolution and high noise levels. With high-resolution sonars, algorithms developed in the image processing field for natural images become applicable. However, the lack of large datasets has hampered the development of such algorithms. Here we present a fast and realistic sonar simulator enabling development and evaluation of such algorithms.We develop a classifier and then analyse its performances using our simulated synthetic sonar images. Finally, we discuss sensor resolution requirements to achieve effective classification of various targets and demonstrate that with high resolution sonars target highlight analysis is the key for target recognition.

  19. Electrical characterization of high-pressure reactive sputtered ScOx films on silicon

    International Nuclear Information System (INIS)

    Castan, H.; Duenas, S.; Gomez, A.; Garcia, H.; Bailon, L.; Feijoo, P.C.; Toledano-Luque, M.; Prado, A. del; San Andres, E.; Lucia, M.L.

    2011-01-01

    Al/ScO x /SiN x /n-Si and Al/ScO x /SiO x /n-Si metal-insulator-semiconductor capacitors have been electrically characterized. Scandium oxide was grown by high-pressure sputtering on different substrates to study the dielectric/insulator interface quality. The substrates were silicon nitride and native silicon oxide. The use of a silicon nitride interfacial layer between the silicon substrate and the scandium oxide layer improves interface quality, as interfacial state density and defect density inside the insulator are decreased.

  20. Dust Continuum Imaging with the Submillimeter High Angular Resolution Camera (SHARC)

    Science.gov (United States)

    Lis, D. C.

    The advent of sensitive bolometer array receivers operating at millimeter and submillimeter wavelengths has allowed large-scale imaging of the distribution of cold dust in star-forming regions. Owing to their high sensitivity and angular resolution, these observations reveal a wealth of structure, including a number of protostellar sources in various evolutionary stages. The Submillimeter High-Angular Resolution Camera (SHARC) is one of the facility instruments at the Caltech Submillimeter Observatory on Mauna Kea, Hawaii. It employs a 20-pixel monolithic silicon bolometer array operating at 300 mK and is used for diffraction limited broad-band continuum imaging at the wavelengths of 350 microns and 450 microns. I present a summary of the results of recent studies of selected Galactic star-forming regions (e.g. Orion A, Orion B, Galactic center, W43), as well as external galaxies (e.g. NGC 891) carried out with SHARC.

  1. Silicone elastomers with high dielectric permittivity and high dielectric breakdown strength based on dipolar copolymers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Daugaard, Anders Egede

    2014-01-01

    Dielectric elastomers (DES) are a promising new transducer technology, but high driving voltages limit their current commercial potential. One method used to lower driving voltage is to increase dielectric permittivity of the elastomer. A novel silicone elastomer system with high dielectric permi......-4-nitrobenzene. Here, a high increase in dielectric permittivity (similar to 70%) was obtained without compromising other favourable DE properties such as elastic modulus, gel fraction, dielectric loss and electrical breakdown strength. © 2014 Elsevier Ltd. All rights reserved.......Dielectric elastomers (DES) are a promising new transducer technology, but high driving voltages limit their current commercial potential. One method used to lower driving voltage is to increase dielectric permittivity of the elastomer. A novel silicone elastomer system with high dielectric...

  2. High-resolution CT findings in Swyer-James syndrome

    International Nuclear Information System (INIS)

    Oh, Yu Whan; Kim, Jung Hyuk; Chung, Kyoo Byung; Suh, Won Hyuck

    1994-01-01

    The purpose of this study was to evaluate. the high-resolution CT features of Swyer-James syndrome with special attention to the airway lesions and to determine the clinical utility of high-resolution CT compared with that of chest radiography. In seven patients with Swyer-James syndrome, we retrospectively reviewed chest radiographs obtained during inspiration and expiration and high-resolution CT scans obtained in inspiration. The high-resolution CT appearance was evaluated and compared with that of chest radiography. On both chest radiographs and high-resolution CT, the affected lung volume was relatively diminished in four patients and normal in three patients. In all seven patients, chest radiographs showed hyperlucency of the lung which was unilateral in four and bilateral in three patients. Unilateral small hilum was seen in six patients and bronchiectasis was demonstrated in one patient on chest radiographs. The hyper lucent lung volume was not diminished on expiratory radiographs in all seven patients. In all patients, high-resolution CT demonstrated low attenuation regions of the lung either bilaterally(n=5) or unilaterally(n=2). Pulmonary vessels were markedly decreased in size and number in the lung parenchyma with low attenuation. Six patients had bronchiectasis on high-resolution CT, which were cylindrical or varicose in five and cystic in one. Bronchiolectasis was observed in three patients on high-resolution CT. The high-resolution CT findings are characteristic of Swyer-James syndrome. High-resolution CT is more sensitive than chest radiography in detecting regions of low attenuation and bronchiectasis and may be useful for the diagnosis of Swyer-James syndrome. Our results suggest that bronchiectasis is a frequently associated airway lesion of Swyer-James syndrome and bronchiolectasis may be associated in some cases

  3. Ultra high resolution X-ray detectors

    International Nuclear Information System (INIS)

    Hess, U.; Buehler, M.; Hentig, R. von; Hertrich, T.; Phelan, K.; Wernicke, D.; Hoehne, J.

    2001-01-01

    CSP Cryogenic Spectrometers GmbH is developing cryogenic energy dispersive X-ray spectrometers based on superconducting detector technology. Superconducting sensors exhibit at least a 10-fold improvement in energy resolution due to their low energy gap compared to conventional Si(Li) or Ge detectors. These capabilities are extremely valuable for the analysis of light elements and in general for the analysis of the low energy range of the X-ray spectrum. The spectrometer is based on a mechanical cooler needing no liquid coolants and an adiabatic demagnetization refrigerator (ADR) stage which supplies the operating temperature of below 100 mK for the superconducting sensor. Applications include surface analysis in semiconductor industry as well material analysis for material composition e.g. in ceramics or automobile industry

  4. Silicon micromachining using a high-density plasma source

    International Nuclear Information System (INIS)

    McAuley, S.A.; Ashraf, H.; Atabo, L.; Chambers, A.; Hall, S.; Hopkins, J.; Nicholls, G.

    2001-01-01

    Dry etching of Si is critical in satisfying the demands of the micromachining industry. The micro-electro-mechanical systems (MEMS) community requires etches capable of high aspect ratios, vertical profiles, good feature size control and etch uniformity along with high throughput to satisfy production requirements. Surface technology systems' (STS's) high-density inductively coupled plasma (ICP) etch tool enables a wide range of applications to be realized whilst optimizing the above parameters. Components manufactured from Si using an STS ICP include accelerometers and gyroscopes for military, automotive and domestic applications. STS's advanced silicon etch (ASE TM ) has also allowed the first generation of MEMS-based optical switches and attenuators to reach the marketplace. In addition, a specialized application for fabricating the next generation photolithography exposure masks has been optimized for 200 mm diameter wafers, to depths of ∼750 μm. Where the profile is not critical, etch rates of greater than 8 μm min -1 have been realized to replace previous methods such as wet etching. This is also the case for printer applications. Specialized applications that require etching down to pyrex or oxide often result in the loss of feature size control at the interface; this is an industry wide problem. STS have developed a technique to address this. The rapid progression of the industry has led to development of the STS ICP etch tool, as well as the process. (author)

  5. Preparation of electrochemically active silicon nanotubes in highly ordered arrays

    Directory of Open Access Journals (Sweden)

    Tobias Grünzel

    2013-10-01

    Full Text Available Silicon as the negative electrode material of lithium ion batteries has a very large capacity, the exploitation of which is impeded by the volume changes taking place upon electrochemical cycling. A Si electrode displaying a controlled porosity could circumvent the difficulty. In this perspective, we present a preparative method that yields ordered arrays of electrochemically competent silicon nanotubes. The method is based on the atomic layer deposition of silicon dioxide onto the pore walls of an anodic alumina template, followed by a thermal reduction with lithium vapor. This thermal reduction is quantitative, homogeneous over macroscopic samples, and it yields amorphous silicon and lithium oxide, at the exclusion of any lithium silicides. The reaction is characterized by spectroscopic ellipsometry for thin silica films, and by nuclear magnetic resonance and X-ray photoelectron spectroscopy for nanoporous samples. After removal of the lithium oxide byproduct, the silicon nanotubes can be contacted electrically. In a lithium ion electrolyte, they then display the electrochemical waves also observed for other bulk or nanostructured silicon systems. The method established here paves the way for systematic investigations of how the electrochemical properties (capacity, charge/discharge rates, cyclability of nanoporous silicon negative lithium ion battery electrode materials depend on the geometry.

  6. Textural Segmentation of High-Resolution Sidescan Sonar Images

    National Research Council Canada - National Science Library

    Kalcic, Maria; Bibee, Dale

    1995-01-01

    .... The high resolution of the 455 kHz sonar imagery also provides much information about the surficial bottom sediments, however their acoustic scattering properties are not well understood at high frequencies...

  7. Step-Stare Image Gathering for High-Resolution Targeting

    National Research Council Canada - National Science Library

    Lavigne, Valerie; Ricard, Benoit

    2005-01-01

    Built around two infrared cameras and a high-speed opto-mechanical pointing mechanism, the Infrared Eye attempts to mimic the human eye by superimposing a high-resolution narrow field of view (first camera...

  8. Crystalline-amorphous core-shell silicon nanowires for high capacity and high current battery electrodes.

    Science.gov (United States)

    Cui, Li-Feng; Ruffo, Riccardo; Chan, Candace K; Peng, Hailin; Cui, Yi

    2009-01-01

    Silicon is an attractive alloy-type anode material for lithium ion batteries because of its highest known capacity (4200 mAh/g). However silicon's large volume change upon lithium insertion and extraction, which causes pulverization and capacity fading, has limited its applications. Designing nanoscale hierarchical structures is a novel approach to address the issues associated with the large volume changes. In this letter, we introduce a core-shell design of silicon nanowires for highpower and long-life lithium battery electrodes. Silicon crystalline-amorphous core-shell nanowires were grown directly on stainless steel current collectors by a simple one-step synthesis. Amorphous Si shells instead of crystalline Si cores can be selected to be electrochemically active due to the difference of their lithiation potentials. Therefore, crystalline Si cores function as a stable mechanical support and an efficient electrical conducting pathway while amorphous shells store Li(+) ions. We demonstrate here that these core-shell nanowires have high charge storage capacity ( approximately 1000 mAh/g, 3 times of carbon) with approximately 90% capacity retention over 100 cycles. They also show excellent electrochemical performance at high rate charging and discharging (6.8 A/g, approximately 20 times of carbon at 1 h rate).

  9. Exploring silicon allotropy and chemistry by high pressure – high temperature conditions

    Science.gov (United States)

    Kurakevych, O. O.; Le Godec, Y.; Strobel, T. A.; Kim, D. Y.; Crichton, W. A.; Guignard, J.

    2017-10-01

    Silicon is the second abundant element, after oxygen, in the earth crust. It is essential for today’s electronics because of its ability to show various electronic behaviors that allow covering the numerous fields of cutting-edge applications. Moreover, silicon is not a pollutant and, therefore, is an ideal candidate to replace the actual materials in photovoltaics, like compounds based on the arsenic and heavy metals. It has not replaced them so far because Si is an indirect gap semiconductor and cannot absorb directly the solar photons without thermal agitations of crystal lattice (phonons). This puts it apart from the next-generation applications (light diode, high-performance transistor). That justifies the attempts to create silicon materials with direct gap that can absorb and emit light. Our recent high-pressure studies of the chemical interaction and phase transformations in the Na-Si system, revealed a number of interesting routes to new and known silicon compounds and allotropes. The pressure-temperature range of their formation is suitable for large-volume synthesis and future industrial scaling. The variety of properties observed (e.g. quasi-direct bandgap of open-framework allotrope Si24) allows us to suggest future industrial applications.

  10. Fabrication of detectors and transistors on high-resistivity silicon

    International Nuclear Information System (INIS)

    Holland, S.

    1988-06-01

    A new process for the fabrication of silicon p-i-n diode radiation detectors is described. The utilization of backside gettering in the fabrication process results in the actual physical removal of detrimental impurities from critical device regions. This reduces the sensitivity of detector properties to processing variables while yielding low diode reverse-leakage currents. In addition, gettering permits the use of processing temperatures compatible with integrated-circuit fabrication. P-channel MOSFETs and silicon p-i-n diodes have been fabricated simultaneously on 10 kΩ/centerreverse arrowdot/cm silicon using conventional integrated-circuit processing techniques. 25 refs., 5 figs

  11. High resolution integral holography using Fourier ptychographic approach.

    Science.gov (United States)

    Li, Zhaohui; Zhang, Jianqi; Wang, Xiaorui; Liu, Delian

    2014-12-29

    An innovative approach is proposed for calculating high resolution computer generated integral holograms by using the Fourier Ptychographic (FP) algorithm. The approach initializes a high resolution complex hologram with a random guess, and then stitches together low resolution multi-view images, synthesized from the elemental images captured by integral imaging (II), to recover the high resolution hologram through an iterative retrieval with FP constrains. This paper begins with an analysis of the principle of hologram synthesis from multi-projections, followed by an accurate determination of the constrains required in the Fourier ptychographic integral-holography (FPIH). Next, the procedure of the approach is described in detail. Finally, optical reconstructions are performed and the results are demonstrated. Theoretical analysis and experiments show that our proposed approach can reconstruct 3D scenes with high resolution.

  12. High-pressure deuterium annealing for improving the reliability characteristics of silicon-oxide-nitride-oxide-silicon nonvolatile memory devices

    Science.gov (United States)

    Choi, Sangmoo; Jang, Man; Park, Hokyung; Hwang, Hyunsang; Jeon, Sanghun; Kim, Juhyung; Kim, Chungwoo

    2004-12-01

    We report the effects of high-pressure deuterium postmetallization annealing on the reliability characteristics of silicon-oxide-nitride-oxide-silicon nonvolatile memory devices. Compared with the control samples annealed in a conventional forming gas ambient (H2/N2=4%/96%), the samples annealed in a high-pressure (10 atm) pure deuterium ambient show improved endurance and retention characteristics without the degradation of program/erase (P/E) speed. In addition, the high-pressure deuterium-annealed samples show a significantly reduced charge loss rate for the electron-stored state and the hole-stored state, before and after the P/E cycles. The improved reliability of the high-pressure deuterium-annealed samples can be explained by the significantly decreased interface trap density and the large kinetic isotope effect of deuterium, which reduces the generation of the interface trap density under the stress of the P/E cycles.

  13. Fabrication of High-Frequency pMUT Arrays on Silicon Substrates

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Zawada, Tomasz; Hansen, Karsten

    2010-01-01

    A novel technique based on silicon micromachining for fabrication of linear arrays of high-frequency piezoelectric micromachined ultrasound transducers (pMUT) is presented. Piezoelectric elements are formed by deposition of lead zirconia titanate into etched features of a silicon substrate...

  14. Silicon Valley: Planet Startup : Disruptive Innovation, Passionate Entrepreneurship & High-tech Startups

    NARCIS (Netherlands)

    dr. A. Maas; Dr. P. Ester

    2016-01-01

    For decades now, Silicon Valley has been the home of the future. It's the birthplace of the world's most successful high-tech companies-including Apple, Yahoo, Google, Facebook, Twitter, and many more. So what's the secret? What is it about Silicon Valley that fosters entrepreneurship and

  15. Study of high energy ion implantation of boron and oxygen in silicon

    International Nuclear Information System (INIS)

    Thevenin, P.

    1991-06-01

    Three aspects of high energy (0.5-3 MeV) light ions ( 11 B + and 16 O + ) implantation in silicon are examined: (1)Spatial repartition; (2) Target damage and (3) Synthesis by oxygen implantation of a buried silicon oxide layer

  16. Silicon-Carbide Power MOSFET Performance in High Efficiency Boost Power Processing Unit for Extreme Environments

    Science.gov (United States)

    Ikpe, Stanley A.; Lauenstein, Jean-Marie; Carr, Gregory A.; Hunter, Don; Ludwig, Lawrence L.; Wood, William; Del Castillo, Linda Y.; Fitzpatrick, Fred; Chen, Yuan

    2016-01-01

    Silicon-Carbide device technology has generated much interest in recent years. With superior thermal performance, power ratings and potential switching frequencies over its Silicon counterpart, Silicon-Carbide offers a greater possibility for high powered switching applications in extreme environment. In particular, Silicon-Carbide Metal-Oxide- Semiconductor Field-Effect Transistors' (MOSFETs) maturing process technology has produced a plethora of commercially available power dense, low on-state resistance devices capable of switching at high frequencies. A novel hard-switched power processing unit (PPU) is implemented utilizing Silicon-Carbide power devices. Accelerated life data is captured and assessed in conjunction with a damage accumulation model of gate oxide and drain-source junction lifetime to evaluate potential system performance at high temperature environments.

  17. Cheetah: A high frame rate, high resolution SWIR image camera

    Science.gov (United States)

    Neys, Joel; Bentell, Jonas; O'Grady, Matt; Vermeiren, Jan; Colin, Thierry; Hooylaerts, Peter; Grietens, Bob

    2008-10-01

    A high resolution, high frame rate InGaAs based image sensor and associated camera has been developed. The sensor and the camera are capable of recording and delivering more than 1700 full 640x512pixel frames per second. The FPA utilizes a low lag CTIA current integrator in each pixel, enabling integration times shorter than one microsecond. On-chip logics allows for four different sub windows to be read out simultaneously at even higher rates. The spectral sensitivity of the FPA is situated in the SWIR range [0.9-1.7 μm] and can be further extended into the Visible and NIR range. The Cheetah camera has max 16 GB of on-board memory to store the acquired images and transfer the data over a Gigabit Ethernet connection to the PC. The camera is also equipped with a full CameralinkTM interface to directly stream the data to a frame grabber or dedicated image processing unit. The Cheetah camera is completely under software control.

  18. High resolution global phase velocity distributions

    Science.gov (United States)

    Trampert, J.; Woodhouse, J. H.

    We present global phase velocity distributions for fundamental mode Love and Rayleigh waves in the period range 40 to 150 seconds. The models, expressed in terms of spherical harmonic expansions up to degree and order 40, have beed derived from 28,479 Love wave and 33,662 Rayleigh wave measurements. The measurements were made using an automatic procedure based on non-linear waveform inversion. We show that the results are characterized by lateral resolving radii between 500 and 850 km, a significant reduction from previous work. The improved global resolution is largely due to the inclusion of many more major arc measurements. The power spectra of the models are much whiter than has previously been found. The results show great similarity to the phase velocity distributions derived from the recent a priori model 3-SMAC, in which the primary relevant features are the crustal thickness and crustal velocity distributions, the cooling oceanic lithosphere and the thick (300km) lithosphere of the continental cratons. The results thus confirm these features. Differences, for example, in the strengths of the crust, ridge and craton signatures should lead to refinement in the thermal and constitutive parameters upon which the a priori model depends.

  19. High-resolution tomographic imaging of microvessels

    Science.gov (United States)

    Müller, Bert; Lang, Sabrina; Dominietto, Marco; Rudin, Markus; Schulz, Georg; Deyhle, Hans; Germann, Marco; Pfeiffer, Franz; David, Christian; Weitkamp, Timm

    2008-08-01

    Cancer belongs to the primary diseases these days. Although different successful treatments including surgery, chemical, pharmacological, and radiation therapies are established, the aggressive proliferation of cancerous cells and the related formation of blood vessels has to be better understood to develop more powerful strategies against the different kinds of cancer. Angiogenesis is one of the crucial steps for the survival and metastasis formation of malignant tumors. Although therapeutic strategies attempting to inhibit these processes are being developed, the biological regulation is still unclear. This study concentrates on the three-dimensional morphology of vessels formed in a mouse tumor xenograft model post mortem. Synchrotron radiation-based micro computed tomography (SRμCT) could provide the necessary information that is essential for validating the simulations. Using mouse and human brain tissue, the different approaches to extract the vessel tree from SRμCT data are discussed. These approaches include corrosion casting, the application of contrast agents such as barium sulfate, tissue embedding, all of them regarded as materials science based. Alternatively, phase contrast tomography was used, which gave rise to promising results but still not reaches the spatial resolution to uncover the smallest capillaries.

  20. An improved IHS fusion for high resolution remote sensing images

    Science.gov (United States)

    Hu, Youjian; Zhang, Xiaohua

    2010-02-01

    Image fusion plays an important role in improving high resolution remote sensing images, as many Earth observation satellites provide both high-resolution panchromatic and multispectral images. To date, many image fusion techniques have been developed. Existing traditional image fusion techniques such as the intensity-hue-saturation (IHS) transform, wavelet transform and principal components analysis(PCA) methods may not be optimal for fusing the new generation commercial high-resolution satellite images such as IKONOS and Quick Bird. However, the available algorithms can hardly meet a satisfactory fusion requirement for high resolution remote sensing images. Among the existing fusion algorithms, the IHS technique is the most widely used one technique. But the color distortion of this technique is often obvious, especially when high resolution multispectral images are fused with its panchromatic images. This study presents a new fusion approach that integrates both IHS and histogram match techniques to reduce the color distortion of high resolution remote sensing fusion results. Different high resolution remote sensing images have been fused with this new approach. The result proves that the concept of the proposed improved IHS is promising, and it does significantly improve the fusion quality compared to conventional IHS transform fusion techniques.

  1. Achieving High Resolution Timer Events in Virtualized Environment.

    Science.gov (United States)

    Adamczyk, Blazej; Chydzinski, Andrzej

    2015-01-01

    Virtual Machine Monitors (VMM) have become popular in different application areas. Some applications may require to generate the timer events with high resolution and precision. This however may be challenging due to the complexity of VMMs. In this paper we focus on the timer functionality provided by five different VMMs-Xen, KVM, Qemu, VirtualBox and VMWare. Firstly, we evaluate resolutions and precisions of their timer events. Apparently, provided resolutions and precisions are far too low for some applications (e.g. networking applications with the quality of service). Then, using Xen virtualization we demonstrate the improved timer design that greatly enhances both the resolution and precision of achieved timer events.

  2. Transition-metal defects in silicon. New insights from photoluminescence studies of highly enriched {sup 28}Si

    Energy Technology Data Exchange (ETDEWEB)

    Steger, Michael

    2013-03-01

    Nominated as an outstanding contribution by Simon Fraser University. Demonstrates the power of isotopic enrichment for high-resolution spectroscopic characterization. Records properties of transition metal centers in silicon with unprecedented accuracy. A valuable step towards the realization of silicon-based lighting. The fundamental properties of deep luminescence centres in Si associated with transition metals such as Cu, Ag, Au, and Pt have been a focus of interest for decades, both as markers for these deleterious contaminants, and also in the quest for efficient Si-based light emission. This dissertation presents the results of ultra-high resolution photoluminescence studies of these centres in specially prepared, highly enriched 28-Si samples. The greatly improved spectral resolution due to this enrichment led to the discovery of isotopic fingerprints. These fingerprints have revealed that the detailed constituents of all of the centres previously studied had been identified incorrectly. They also revealed the existence of several different families of impurity complexes containing either four or five atoms chosen from Li, Cu, Ag, Au, and Pt. These centres' constituents have been determined, together with no-phonon transition energies, no-phonon isotope shifts, local vibrational mode energies, and the isotope shifts of the local vibrational mode energies. The data presented here for these centres should prove useful for the currently sought theoretical explanations of their formation, stability, and properties.

  3. Reproducible high-resolution multispectral image acquisition in dermatology

    Science.gov (United States)

    Duliu, Alexandru; Gardiazabal, José; Lasser, Tobias; Navab, Nassir

    2015-07-01

    Multispectral image acquisitions are increasingly popular in dermatology, due to their improved spectral resolution which enables better tissue discrimination. Most applications however focus on restricted regions of interest, imaging only small lesions. In this work we present and discuss an imaging framework for high-resolution multispectral imaging on large regions of interest.

  4. High-resolution spectroscopy of gases for industrial applications

    DEFF Research Database (Denmark)

    Fateev, Alexander; Clausen, Sønnik

    High-resolution spectroscopy of gases is a powerful technique which has various fundamental and practical applications: in situ simultaneous measurements of gas temperature and gas composition, radiative transfer modeling, validation of existing and developing of new databases and etc. Existing...... to, for example, atmospheric research, combustion and gasification. Some high-temperature, high-resolution IR/UV absorption/transmission measurements gases (e.g. CO2, SO2, SO3 and phenol) are presented....

  5. Ultra-high-resolution alpha spectrometry for nuclear forensics and safeguards applications

    International Nuclear Information System (INIS)

    Bacrania, Minesh K.; Croce, Mark; Bond, Evelyn; Dry, Donald; Moody, W. Allen; Lamont, Stephen; Rabin, Michael; Rim, Jung; Smith, Audrey; Beall, James; Bennett, Douglas; Kotsubo, Vincent; Horansky, Robert; Hilton, Gene; Schmidt, Daniel; Ullom, Joel; Cantor, Robin

    2010-01-01

    We will present our work on the development of ultra-high-resolution detectors for alpha particle spectrometry. These detectors, based on superconducting transition-edge sensors, offer energy resolution that is five to ten times better than conventional silicon detectors. Using these microcalorimeter detectors, the isotopic composition of mixed-actinide samples can be determined rapidly without the need for actinide separation chemistry to isolate each element, or mass spectrometry to separate isotopic signatures that can not be resolved using traditional alpha spectrometry (e.g. Pu-239/Pu-240, or Pu-238/Am-241). This paper will cover the detector and measurement system, actinide source preparation, and the quantitative isotopic analysis of a number of forensics- and safeguards-relevant radioactive sources.

  6. Developing a High Thermal Conductivity Fuel with Silicon Carbide Additives

    Energy Technology Data Exchange (ETDEWEB)

    baney, Ronald; Tulenko, James

    2012-11-20

    The objective of this research is to increase the thermal conductivity of uranium oxide (UO{sub 2}) without significantly impacting its neutronic properties. The concept is to incorporate another high thermal conductivity material, silicon carbide (SiC), in the form of whiskers or from nanoparticles of SiC and a SiC polymeric precursor into UO{sub 2}. This is expected to form a percolation pathway lattice for conductive heat transfer out of the fuel pellet. The thermal conductivity of SiC would control the overall fuel pellet thermal conductivity. The challenge is to show the effectiveness of a low temperature sintering process, because of a UO{sub 2}-SiC reaction at 1,377°C, a temperature far below the normal sintering temperature. Researchers will study three strategies to overcome the processing difficulties associated with pore clogging and the chemical reaction of SiC and UO{sub 2} at temperatures above 1,300°C:

  7. Funnel-shaped silicon nanowire for highly efficient light trapping.

    Science.gov (United States)

    Hussein, Mohamed; Hameed, Mohamed Farhat O; Areed, Nihal F F; Yahia, Ashraf; Obayya, S S A

    2016-03-01

    In this Letter, funnel-shaped silicon nanowires (SiNWs) are newly introduced for highly efficient light trapping. The proposed designs of nanowires are inspired by the funnel shape, which enhances the light trapping with reduced reflections in the wavelength range from 300 to 1100 nm. Composed of both cylindrical and conical units, the funnel nanowires increase the number of leaky mode resonances, yielding an absorption enhancement relative to a uniform nanowire array. The optical properties of the suggested nanowires have been numerically investigated using the 3D finite difference time domain (FDTD) method and compared to cylindrical and conical counterparts. The structural geometrical parameters are studied to maximize the ultimate efficiency and hence the short-circuit current. Carefully engineered structure geometry is shown to yield improved light absorption useful for solar cell applications. The proposed funnel-shaped SiNWs offer an ultimate efficiency of 41.8%, with an enhancement of 54.8% relative to conventional cylindrical SiNWs. Additionally, short-circuit current of 34.2  mA/cm2 is achieved using the suggested design.

  8. Silicon photomultipliers. Properties and applications in a highly granular calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Feege, Nils

    2008-12-15

    Silicon Photomultipliers (SiPMs) are novel semiconductor-based photodetectors operated in Geiger mode. Their response is not linear, and both their gain and their photon detection efficiency depend on the applied bias voltage and on temperature. The CALICE collaboration investigates several technology options for highly granular calorimeters for the future ILC. The prototype of a scintillator-steel sampling calorimeter with analogue readout for hadrons constructed at DESY and successfully operated in testbeam experiments at DESY, CERN and FNAL by this collaboration is the first large scale application for 7608 SiPMs developed by MEPhI. This thesis deals with properties of the SiPMs used in the calorimeter prototype. The effective numer of pixels of the SiPMs, which influences their saturation behaviour, is extracted from in situ measurements and compared to results obtained for the bare SiPMs. In addition, the effects of temperature and voltage changes on the parameters necessary for the calibration of the SiPMs and the detector are determined. Methods which allow for correcting or compensating these effects are evaluated. An approach to improve the absolute calibration of the temperature sensors in the prototype is described and temperature profiles are studied. Finally, a procedure to adjust the light yield of the cells of the prototype is presented. The results of the application of this procedure during the commissioning of the detector at FNAL are discussed. (orig.)

  9. High Temperature Dynamic Pressure Measurements Using Silicon Carbide Pressure Sensors

    Science.gov (United States)

    Okojie, Robert S.; Meredith, Roger D.; Chang, Clarence T.; Savrun, Ender

    2014-01-01

    Un-cooled, MEMS-based silicon carbide (SiC) static pressure sensors were used for the first time to measure pressure perturbations at temperatures as high as 600 C during laboratory characterization, and subsequently evaluated in a combustor rig operated under various engine conditions to extract the frequencies that are associated with thermoacoustic instabilities. One SiC sensor was placed directly in the flow stream of the combustor rig while a benchmark commercial water-cooled piezoceramic dynamic pressure transducer was co-located axially but kept some distance away from the hot flow stream. In the combustor rig test, the SiC sensor detected thermoacoustic instabilities across a range of engine operating conditions, amplitude magnitude as low as 0.5 psi at 585 C, in good agreement with the benchmark piezoceramic sensor. The SiC sensor experienced low signal to noise ratio at higher temperature, primarily due to the fact that it was a static sensor with low sensitivity.

  10. TRANSFORMATIONS IN NANO-DIAMONDS WITH FORMATION OF NANO-POROUS SILICON CARBIDE AT HIGH PRESSURE

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevsky

    2010-01-01

    Full Text Available The paper contains investigations on regularities of diamond - silicon carbide composite structure formation at impact-wave excitation. It has been determined that while squeezing a porous blank containing Si (SiC nano-diamond by explosive detonation products some processes are taking place such as diamond nano-particles consolidation, reverse diamond transition into graphite, fragments formation from silicon carbide. A method for obtaining high-porous composites with the presence of ultra-disperse diamond particles has been developed. Material with three-dimensional high-porous silicon-carbide structure has been received due to nano-diamond graphitation at impact wave transmission and plastic deformation. The paper reveals nano-diamonds inverse transformation into graphite and its subsequent interaction with the silicon accompanied by formation of silicon-carbide fragments with dimensions of up to 100 nm.

  11. Silicon Framework-Based Lithium Silicides at High Pressures.

    Science.gov (United States)

    Zhang, Shoutao; Wang, Yanchao; Yang, Guochun; Ma, Yanming

    2016-07-06

    The bandgap and optical properties of diamond silicon (Si) are not suitable for many advanced applications such as thin-film photovoltaic devices and light-emitting diodes. Thus, finding new Si allotropes with better bandgap and optical properties is desirable. Recently, a Si allotrope with a desirable bandgap of ∼1.3 eV was obtained by leaching Na from NaSi6 that was synthesized under high pressure [Nat. Mater. 2015, 14, 169], paving the way to finding new Si allotropes. Li is isoelectronic with Na, with a smaller atomic core and comparable electronegativity. It is unknown whether Li silicides share similar properties, but it is of considerable interest. Here, a swarm intelligence-based structural prediction is used in combination with first-principles calculations to investigate the chemical reactions between Si and Li at high pressures, where seven new compositions (LiSi4, LiSi3, LiSi2, Li2Si3, Li2Si, Li3Si, and Li4Si) become stable above 8.4 GPa. The Si-Si bonding patterns in these compounds evolve with increasing Li content sequentially from frameworks to layers, linear chains, and eventually isolated Si ions. Nearest-neighbor Si atoms, in Cmmm-structured LiSi4, form covalent open channels hosting one-dimensional Li atom chains, which have similar structural features to NaSi6. The analysis of integrated crystal orbital Hamilton populations reveals that the Si-Si interactions are mainly responsible for the structural stability. Moreover, this structure is dynamically stable even at ambient pressure. Our results are also important for understanding the structures and electronic properties of Li-Si binary compounds at high pressures.

  12. A novel VLSI processor for high-rate, high resolution spectroscopy

    CERN Document Server

    Pullia, Antonio; Gatti, E; Longoni, A; Buttler, W

    2000-01-01

    A novel time-variant VLSI shaper amplifier, suitable for multi-anode Silicon Drift Detectors or other multi-element solid-state X-ray detection systems, is proposed. The new read-out scheme has been conceived for demanding applications with synchrotron light sources, such as X-ray holography or EXAFS, where both high count-rates and high-energy resolutions are required. The circuit is of the linear time-variant class, accepts randomly distributed events and features: a finite-width (1-10 mu s) quasi-optimal weight function, an ultra-low-level energy discrimination (approx 150 eV), and a full compatibility for monolithic integration in CMOS technology. Its impulse response has a staircase-like shape, but the weight function (which is in general different from the impulse response in time-variant systems) is quasi trapezoidal. The operation principles of the new scheme as well as the first experimental results obtained with a prototype of the circuit are presented and discussed in the work.

  13. A high time resolution x-ray diagnostic on the Madison Symmetric Torus

    Science.gov (United States)

    DuBois, Ami M.; Lee, John David; Almagri, Abdulgadar F.

    2015-07-01

    A new high time resolution x-ray detector has been installed on the Madison Symmetric Torus (MST) to make measurements around sawtooth events. The detector system is comprised of a silicon avalanche photodiode, a 20 ns Gaussian shaping amplifier, and a 500 MHz digitizer with 14-bit sampling resolution. The fast shaping time diminishes the need to restrict the amount of x-ray flux reaching the detector, limiting the system dead-time. With a much higher time resolution than systems currently in use in high temperature plasma physics experiments, this new detector has the versatility to be used in a variety of discharges with varying flux and the ability to study dynamics on both slow and fast time scales. This paper discusses the new fast x-ray detector recently installed on MST and the improved time resolution capabilities compared to the existing soft and hard x-ray diagnostics. In addition to the detector hardware, improvements to the detector calibration and x-ray pulse identification software, such as additional fitting parameters and a more sophisticated fitting routine are discussed. Finally, initial data taken in both high confinement and standard reversed-field pinch plasma discharges are compared.

  14. High-resolution setup for measuring wavelength sensitivity of photoyellowing of translucent materials

    Energy Technology Data Exchange (ETDEWEB)

    Vaskuri, Anna, E-mail: anna.vaskuri@aalto.fi; Kärhä, Petri [Metrology Research Institute, Aalto University, P.O. Box 13000, FI-00076 Aalto (Finland); Heikkilä, Anu [R& D/Climate Research, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki (Finland); Ikonen, Erkki [Metrology Research Institute, Aalto University, P.O. Box 13000, FI-00076 Aalto (Finland); MIKES Metrology, VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT (Finland)

    2015-10-15

    Polystyrene and many other materials turn yellow when exposed to ultraviolet (UV) radiation. All photodegradation mechanisms including photoyellowing are functions of the exposure wavelength, which can be described with an action spectrum. In this work, a new high-resolution transmittance measurement setup based on lasers has been developed for measuring color changes, such as the photoyellowing of translucent materials aged with a spectrograph. The measurement setup includes 14 power-stabilized laser lines between 325 nm and 933 nm wavelengths, of which one at a time is directed on to the aged sample. The power transmitted through the sample is measured with a silicon detector utilizing an integrating sphere. The sample is mounted on a high-resolution XY translation stage. Measurement at various locations aged with different wavelengths of exposure radiation gives the transmittance data required for acquiring the action spectrum. The combination of a UV spectrograph and the new high-resolution transmittance measurement setup enables a novel method for studying the UV-induced ageing of translucent materials with a spectral resolution of 3–8 nm, limited by the adjustable spectral bandwidth range of the spectrograph. These achievements form a significant improvement over earlier methods.

  15. Metallurgy of high-silicon steel parts produced using Selective Laser Melting

    OpenAIRE

    Garibaldi, Michele; Ashcroft, Ian; Simonelli, Marco; Hague, Richard

    2016-01-01

    The metallurgy of high-silicon steel (6.9%wt.Si) processed using Selective Laser Melting (SLM) is presented for the first time in this study. High-silicon steel has great potential as a soft magnetic alloy, but its employment has been limited due to its poor workability. The effect of SLM-processing on the metallurgy of the alloy is investigated in this work using microscopy, X-Ray Diffraction (XRD) and Electron Backscatter Diffraction (EBSD). XRD analysis suggests that the SLM high-silicon s...

  16. Frictional characteristics of silicon graphite lubricated with water at high pressure and high temperature

    International Nuclear Information System (INIS)

    Lee, Jae Seon; Kim, Eun Hyun; Park, Jin Seok; Kim, Jong In

    2001-01-01

    Experimental frictional and wear characteristics of silicon graphite materials is studied in this paper. Those specimens are lubricated with high temperature and highly pressurized water to simulate the same operating condition for the journal bearing and the thrust bearing on the main coolant pump bearing in the newly developing nuclear reactor named SMART(System-integrated Modular Advanced ReacTor). Operating condition of the bearings is realized by the tribometer and the autoclave. Friction coefficient and wear loss are analyzed to choose the best silicon graphite material. Pin on plate test specimens are used and coned disk springs are used to control the applied force on the specimens. Wear loss and wear width are measured by a precision balance and a micrometer. The friction force is measured by the strain gauge which can be used under high temperature and high pressure. Three kinds of silicon graphite materials are examined and compared with each other, and each material shows similar but different results on frictional and wear characteristics

  17. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed

    2014-07-29

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  18. Multi element high resolution scintillator structure

    International Nuclear Information System (INIS)

    Cusano, D.A.

    1980-01-01

    A gamma camera scintillator structure, suitable for detecting high energy gamma photons which, in a single scintillator camera, would require a comparatively thick scintillator crystal, so resulting in unacceptable dispersion of light photons, comprises a collimator array of a high Z material with elongated, parallel wall channels with the scintillator material being disposed in one end of the channels so as to form an integrated collimator/scintillator structure. The collimator channel walls are preferably coated with light reflective material and further light reflective surfaces being translucent to gamma photons, may be provided in each channel. The scintillators may be single crystals or preferably comprise a phosphor dispersed in a thermosetting translucent matrix as disclosed in GB2012800A. The light detectors of the assembled camera may be photomultiplier tubes charge coupled devices or charge injection devices. (author)

  19. A Forward-Looking High-Resolution GPR System

    National Research Council Canada - National Science Library

    Kositsky, Joel; Milanfar, Peyman

    1999-01-01

    A high-resolution ground penetrating radar (GPR) system was designed to help define the optimal radar parameters needed for the efficient standoff detection of buried and surface-laid antitank mines...

  20. NOAA High-Resolution Sea Surface Temperature (SST) Analysis Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archive covers two high resolution sea surface temperature (SST) analysis products developed using an optimum interpolation (OI) technique. The analyses have a...

  1. High Resolution, Range/Range-Rate Imager Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Visidyne proposes to develop a design for a small, lightweight, high resolution, in x, y, and z Doppler imager to assist in the guidance, navigation and control...

  2. Hurricane Satellite (HURSAT) from Advanced Very High Resolution Radiometer (AVHRR)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Huricane Satellite (HURSAT)-Advanced Very High Resolution Radiometer (AVHRR) is used to extend the HURSAT data set such that appling the Objective Dvorak technique...

  3. Scene Classification Using High Spatial Resolution Multispectral Data

    National Research Council Canada - National Science Library

    Garner, Jamada

    2002-01-01

    ...), High-spatial resolution (8-meter), 4-color MSI data from IKONOS provide a new tool for scene classification, The utility of these data are studied for the purpose of classifying the Elkhorn Slough and surrounding wetlands in central...

  4. Methodology of high-resolution photography for mural condition database

    Science.gov (United States)

    Higuchi, R.; Suzuki, T.; Shibata, M.; Taniguchi, Y.

    2015-08-01

    Digital documentation is one of the most useful techniques to record the condition of cultural heritage. Recently, high-resolution images become increasingly useful because it is possible to show general views of mural paintings and also detailed mural conditions in a single image. As mural paintings are damaged by environmental stresses, it is necessary to record the details of painting condition on high-resolution base maps. Unfortunately, the cost of high-resolution photography and the difficulty of operating its instruments and software have commonly been an impediment for researchers and conservators. However, the recent development of graphic software makes its operation simpler and less expensive. In this paper, we suggest a new approach to make digital heritage inventories without special instruments, based on our recent our research project in Üzümlü church in Cappadocia, Turkey. This method enables us to achieve a high-resolution image database with low costs, short time, and limited human resources.

  5. A temperature-compensated high spatial resolution distributed strain sensor

    International Nuclear Information System (INIS)

    Belal, Mohammad; Cho, Yuh Tat; Ibsen, Morten; Newson, Trevor P

    2010-01-01

    We propose and demonstrate a scheme which utilizes the temperature dependence of spontaneous Raman scattering to provide temperature compensation for a high spatial resolution Brillouin frequency-based strain sensor

  6. High-resolution SPECT for small-animal imaging

    International Nuclear Information System (INIS)

    Qi Yujin

    2006-01-01

    This article presents a brief overview of the development of high-resolution SPECT for small-animal imaging. A pinhole collimator has been used for high-resolution animal SPECT to provide better spatial resolution and detection efficiency in comparison with a parallel-hole collimator. The theory of imaging characteristics of the pinhole collimator is presented and the designs of the pinhole aperture are discussed. The detector technologies used for the development of small-animal SPECT and the recent advances are presented. The evolving trend of small-animal SPECT is toward a multi-pinhole and a multi-detector system to obtain a high resolution and also a high detection efficiency. (authors)

  7. High-Resolution Reciprocal Space Mapping for Characterizing Deformation Structures

    DEFF Research Database (Denmark)

    Pantleon, Wolfgang; Wejdemann, Christian; Jakobsen, Bo

    2014-01-01

    With high-angular resolution three-dimensional X-ray diffraction (3DXRD), quantitative information is gained about dislocation structures in individual grains in the bulk of a macroscopic specimen by acquiring reciprocal space maps. In high-resolution 3D reciprocal space maps of tensile-deformed ......With high-angular resolution three-dimensional X-ray diffraction (3DXRD), quantitative information is gained about dislocation structures in individual grains in the bulk of a macroscopic specimen by acquiring reciprocal space maps. In high-resolution 3D reciprocal space maps of tensile...... dynamics is followed in situ during varying loading conditions by reciprocal space mapping: during uninterrupted tensile deformation, formation of subgrains is observed concurrently with broadening of Bragg reflections shortly after the onset of plastic deformation. When the traction is terminated, stress...

  8. Very high resolution satellite data: New challenges in image analysis

    Digital Repository Service at National Institute of Oceanography (India)

    Sathe, P.V.; Muraleedharan, P.M.

    or other natural landscapes. Having very high resolution digital data over a landscape will however create new challenges in the field of atmospheric correction, ground registration, image processing and finally the image interpretation itself. Even...

  9. Methods of photoelectrode characterization with high spatial and temporal resolution

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, Daniel V. [Department of Chemical Engineering; Columbia University in the City of New York; New York; USA; National Institute of Standards and Technology; Baxter, Jason B. [Department of Chemical and Biological Engineering; Drexel University; Philadelphia; USA; John, Jimmy [Division of Chemistry and Chemical Engineering; California Institute of Technology; Pasadena; USA; Lewis, Nathan S. [Division of Chemistry and Chemical Engineering; California Institute of Technology; Pasadena; USA; Joint Center for Artificial Photosynthesis; Moffat, Thomas P. [National Institute of Standards and Technology; Gaithersburg; USA; Ogitsu, Tadashi [Quantum Simulations Group; Lawrence Livermore National Laboratory; Livermore; USA; O' Neil, Glen D. [Department of Chemical Engineering; Columbia University in the City of New York; New York; USA; Pham, Tuan Anh [Quantum Simulations Group; Lawrence Livermore National Laboratory; Livermore; USA; Talin, A. Alec [Sandia National Laboratories; Livermore; USA; Velazquez, Jesus M. [Division of Chemistry and Chemical Engineering; California Institute of Technology; Pasadena; USA; Joint Center for Artificial Photosynthesis; Wood, Brandon C. [Quantum Simulations Group; Lawrence Livermore National Laboratory; Livermore; USA

    2015-01-01

    This article reviews computational andin situexperimental tools capable of characterizing the properties and performance of photoelectrodes used for solar fuels production with high spatial and temporal resolution.

  10. NanoComposite Polymers for High Resolution Near Infrared Detectors

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop nanocomposite materials with tuned refractive index in the near infra red spectral range as an index-matched immersion lens for high resolution infra-red...

  11. High-efficiency blazed transmission gratings for high-resolution soft x-ray spectroscopy

    Science.gov (United States)

    Heilmann, Ralf K.; Bruccoleri, Alexander R.; Schattenburg, Mark L.

    2015-09-01

    High-resolution spectroscopy of astrophysical sources is the key to gaining a quantitative understanding of the history, dynamics, and current conditions of the cosmos. A large-area (> 1,000 cm2), high resolving power (R = λ/Δλ> 3000) soft x-ray grating spectrometer (XGS) that covers the lines of C, N, O, Ne and Fe ions is the ideal tool to address a number of high-priority science questions from the 2010 Decadal Survey, such as the connection between super-massive black holes and large-scale structure via cosmic feedback, the evolution of large- scale structure, the behavior of matter at high densities, and the conditions close to black holes. While no grating missions or instruments are currently approved, an XGS aboard a potential future X-ray Surveyor could easily surpass the above performance metrics. To improve the chances for future soft x-ray grating spectroscopy missions or instruments, grating technology has to progress and advance to higher Technology Readiness Levels (TRLs). To that end we have developed Critical-Angle Transmission (CAT) gratings that combine the advantages of blazed reflection gratings (high efficiency, use of higher diffraction orders) with those of conventional transmission gratings (low mass, relaxed alignment tolerances and temperature requirements, high transparency at higher energies). A CAT grating-based spectrometer can provide performance 1-2 orders of magnitude better than current grating instruments on Chandra and Newton-XMM with minimal resource requirements. At present we have fabricated large-area freestanding CAT gratings with narrow integrated support structures from silicon-on- insulator wafers using advanced lithography and a combination of deep reactive-ion and wet etching. Our latest x-ray test results show record high absolute diffraction efficiencies in blazed orders in excess of 30% with room for improvement.

  12. Proton-irradiation technology for high-frequency high-current silicon welding diode manufacturing

    Science.gov (United States)

    Lagov, P. B.; Drenin, A. S.; Zinoviev, M. A.

    2017-05-01

    Different proton irradiation regimes were tested to provide more than 20 kHz-frequency, soft reverse recovery “snap-less” behavior, low forward voltage drop and leakage current for 50 mm diameter 7 kA/400 V welding diode Al/Si/Mo structure. Silicon diode with such parameters is very suitable for high frequency resistance welding machines of new generation for robotic welding.

  13. High efficiency hybrid silicon nanopillar-polymer solar cells.

    Science.gov (United States)

    Pudasaini, Pushpa Raj; Ruiz-Zepeda, Francisco; Sharma, Manisha; Elam, David; Ponce, Arturo; Ayon, Arturo A

    2013-10-09

    Recently, inorganic/organic hybrid solar cells have been considered as a viable alternative for low-cost photovoltaic devices because the Schottky junction between inorganic and organic materials can be formed employing low temperature processing methods. We present an efficient hybrid solar cell based on highly ordered silicon nanopillars (SiNPs) and poly(3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS). The proposed device is formed by spin coating the organic polymer PEDOT:PSS on a SiNP array fabricated using metal assisted electroless chemical etching process. The characteristics of the hybrid solar cells are investigated as a function of SiNP height. A maximum power conversion efficiency (PCE) of 9.65% has been achieved for an optimized SiNP array hybrid solar cell with nanopillar height of 400 nm, despite the absence of a back surface field enhancement. The effect of an ultrathin atomic layer deposition (ALD), grown aluminum oxide (Al2O3), as a passivation layer (recombination barrier) has also been studied for the enhanced electrical performance of the device. With the inclusion of the ultrathin ALD deposited Al2O3 between the SiNP array textured surface and the PEDOT:PSS layer, the PCE of the fabricated device was observed to increase to 10.56%, which is ∼10% greater than the corresponding device without the Al2O3 layer. The device described herein is considered to be promising toward the realization of a low-cost, high-efficiency inorganic/organic hybrid solar cell.

  14. Dynamics of High-Resolution Networks

    DEFF Research Database (Denmark)

    Sekara, Vedran

    NETWORKS are everywhere. From the smallest confines of the cells within our bodies to the webs of social relations across the globe. Networks are not static, they constantly change, adapt, and evolve to suit new conditions. In order to understand the fundamental laws that govern networks we need...... the unprecedented amounts of information collected by mobile phones to gain detailed insight into the dynamics of social systems. This dissertation presents an unparalleled data collection campaign, collecting highly detailed traces for approximately 1000 people over the course of multiple years. The availability...

  15. COST EFFECTIVE AND HIGH RESOLUTION SUBSURFACE CHARACTERIZATION USING HYDRAULIC TOMOGRAPHY

    Science.gov (United States)

    2017-08-01

    see that Approaches 1 and 2 are comparable in terms of costs if the equipment costs for hydraulic tomography are not accounted for. Equipment costs ...FINAL REPORT Cost -Effective and High-Resolution Subsurface Characterization Using Hydraulic Tomography ESTCP Project ER-201212 AUGUST...TITLE AND SUBTITLE 5a. CONTRACT NUMBER W912HQ-12-C-0024 COST -EFFECTIVE AND HIGH-RESOLUTION SUBSURFACE CHARACTERIZATION USING HYDRAULIC TOMOGRAPHY

  16. ON THE DESIGN OF HIGH RESOLUTION IMAGING SYSTEMS

    Directory of Open Access Journals (Sweden)

    A. Eckardt

    2017-05-01

    Full Text Available The design of high-resolution systems is always a consideration of many parameters. Technological parameter of the imaging system, e.g. diameter of the imaging system, mass and power, as well as storage and data transfer, have an direct impact on spacecraft size and design. The paper describes the essential design parameters for the description of high-resolution systems.

  17. High Resolution UV Spectroscopy for Solar System Exploration

    Science.gov (United States)

    Ajello, J. M.; Kanik, I.; James, G.; Liu, X.; Ciocca, M.; Noren, C.; Shemansky, D.

    1996-01-01

    A new generation of high resolution UV imaging spacecraft (Polar, Galileo, HST) are studying the airglow and aurora of the Earth and the jovian planets. To keep pace with these technological improvements we have developed a laboratory program to provide electron collision cross sections of the major molecular planetary gasses. Molecular spectra under optically thin conditions have been measured with a high resolution UV spectrometer in tandem with an electron impact collision chamber. The results of various studies are reported in this paper.

  18. Achieving Optimal High Resolution In Galvanometric Scanning Systems

    Science.gov (United States)

    Montagu, Jean I.

    1986-05-01

    This paper discusses methods of achieving the optimum in high resolution galvanometric scanning. When scanning systems have problems of repeatability, jitter, and wobble, the difficulties are often caused by inadequate mirror design, bonding, and/or alignment and the dynamic forces engendered by the driving torque. These issues are examined, and integral metal mirror mounts are compared with the conventional composite mirrors bonded to metal mounts. Galvanometer bearing suspension and drive electronics and how they relate to optimal high resolution are also addressed.

  19. Developing Visual Editors for High-Resolution Haptic Patterns

    DEFF Research Database (Denmark)

    Cuartielles, David; Göransson, Andreas; Olsson, Tony

    2012-01-01

    In this article we give an overview of our iterative work in developing visual editors for creating high resolution haptic patterns to be used in wearable, haptic feedback devices. During the past four years we have found the need to address the question of how to represent, construct and edit high...... resolution haptic patterns so that they translate naturally to the user’s haptic experience. To solve this question we have developed and tested several visual editors...

  20. High-speed digitization readout of silicon photomultipliers for time of flight positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ronzhin, A.; Los, S.; Martens, M.; Ramberg, E.; /Fermilab; Kim, H.; Chen, C.; Kao, C.; /Chicago U.; Niessen, K.; /SUNY, Buffalo; Zatserklyaniy, A.; /Puerto Rico U., Mayaguez; Mazzillo, M.; Carbone, B.; /SGS Thomson, Catania

    2011-02-01

    We report on work to develop a system with about 100 picoseconds (ps) time resolution for time of flight positron emission tomography [TOF-PET]. The chosen photo detectors for the study were Silicon Photomultipliers (SiPM's). This study was based on extensive experience in studying timing properties of SiPM's. The readout of these devices used the commercial high speed digitizer DRS4. We applied different algorithms to get the best time resolution of 155 ps Guassian (sigma) for a LYSO crystal coupled to a SiPM. We consider the work as a first step in building a prototype TOF-PET module. The field of positron-emission-tomography (PET) has been rapidly developing. But there are significant limitations in how well current PET scanners can reconstruct images, related to how fast data can be acquired, how much volume they can image, and the spatial and temporal resolution of the generated photons. Typical modern scanners now include multiple rings of detectors, which can image a large volume of the patient. In this type of scanner, one can treat each ring as a separate detector and require coincidences only within the ring, or treat the entire region viewed by the scanner as a single 3 dimensional volume. This 3d technique has significantly better sensitivity since more photon pair trajectories are accepted. However, the scattering of photons within the volume of the patient, and the effect of random coincidences limits the technique. The advent of sub-nanosecond timing resolution detectors means that there is potentially much better rejection of scattered photon events and random coincidence events in the 3D technique. In addition, if the timing is good enough, then the origin of photons pairs can be determined better, resulting in improved spatial resolution - so called 'Time-of-Flight' PET, or TOF-PET. Currently a lot of activity has occurred in applications of SiPMs for TOF-PET. This is due to the devices very good time resolution, low profile

  1. High resolution RGB color line scan camera

    Science.gov (United States)

    Lynch, Theodore E.; Huettig, Fred

    1998-04-01

    A color line scan camera family which is available with either 6000, 8000 or 10000 pixels/color channel, utilizes off-the-shelf lenses, interfaces with currently available frame grabbers, includes on-board pixel by pixel offset correction, and is configurable and controllable via RS232 serial port for computer controlled or stand alone operation is described in this paper. This line scan camera is based on an available 8000 element monochrome line scan camera designed by AOA for OEM use. The new color version includes improvements such as better packaging and additional user features which make the camera easier to use. The heart of the camera is a tri-linear CCD sensor with on-chip color balancing for maximum accuracy and pinned photodiodes for low lag response. Each color channel is digitized to 12 bits and all three channels are multiplexed together so that the resulting camera output video is either a 12 or 8 bit data stream at a rate of up to 24Megpixels/sec. Conversion from 12 to 8 bit, or user-defined gamma, is accomplished by on board user-defined video look up tables. The camera has two user-selectable operating modes; lows speed, high sensitivity mode or high speed, reduced sensitivity mode. The intended uses of the camera include industrial inspection, digital archiving, document scanning, and graphic arts applications.

  2. Use of low energy hydrogen ion implants in high efficiency crystalline silicon solar cells

    Science.gov (United States)

    Fonash, S. J.; Singh, R.

    1985-01-01

    This program is a study of the use of low energy hydrogen ion implantation for high efficiency crystalline silicon solar cells. The first quarterly report focuses on two tasks of this program: (1) an examination of the effects of low energy hydrogen implants on surface recombination speed; and (2) an examination of the effects of hydrogen on silicon regrowth and diffusion in silicon. The first part of the project focussed on the measurement of surface properties of hydrogen implanted silicon. Low energy hydrogen ions when bombarded on the silicon surface will create structural damage at the surface, deactivate dopants and introduce recombination centers. At the same time the electrically active centers such as dangling bonds will be passivated by these hydrogen ions. Thus hydrogen is expected to alter properties such as the surface recombination velocity, dopant profiles on the emitter, etc. In this report the surface recombination velocity of a hydrogen emplanted emitter was measured.

  3. High yield silicon carbide from alkylated or arylated pre-ceramic polymer

    International Nuclear Information System (INIS)

    Baney, R.H.; Gaul, J.H.

    1982-01-01

    Alkylated or arylated methylpolysilanes which exhibit ease of handling and are used to obtain silicon carbide ceramic materials in high yields contain 0 to 60 mole percent (CH 3 ) 2 Si double bond units and 40 to 100 mole percent CH 3 Si triple bond units, wherein there is also bonded to the silicon atoms other silicon atoms and additional alkyl radicals of 1 to 4 carbon atoms or phenyl. They may be prepared by reaction of a Grignard reagent RMgX, where X is halogen and R is Csub(1-4)-alkyl or phenyl, with a starting material which is a solid at 25 0 C, and is identical to the product except that the remaining bonds on the silicon atoms are attached to another silicon atom, or a chlorine or a bromine atom. Ceramics result from heating the polysilane products to 1200 0 C, optionally with fillers. (author)

  4. High impact ionization rate in silicon by sub-picosecond THz electric field pulses (Conference Presentation)

    DEFF Research Database (Denmark)

    Tarekegne, Abebe Tilahun; Iwaszczuk, Krzysztof; Hirori, Hideki

    2017-01-01

    near the antenna tips is measured. Using the NIR probing technique, we observed that the density of carriers increases by over 8 orders of magnitude in a time duration of approximately 500 fs with an incident THz pulse of peak electric field strength 700 kV/cm. This shows that a single impact......Summary form only given. Metallic antenna arrays fabricated on high resistivity silicon are used to localize and enhance the incident THz field resulting in high electric field pulses with peak electric field strength reaching several MV/cm on the silicon surface near the antenna tips. In such high...... electric field strengths high density of carriers are generated in silicon through impact ionization process. The high density of generated carriers induces a change of refractive index in silicon. By measuring the change of reflectivity of tightly focused 800 nm light, the local density of free carriers...

  5. High-resolution simulations of turbidity currents

    Science.gov (United States)

    Biegert, Edward; Vowinckel, Bernhard; Ouillon, Raphael; Meiburg, Eckart

    2017-12-01

    We employ direct numerical simulations of the three-dimensional Navier-Stokes equations, based on a continuum formulation for the sediment concentration, to investigate the physics of turbidity currents in complex situations, such as when they interact with seafloor topography, submarine engineering infrastructure and stratified ambients. In order to obtain a more accurate representation of the dynamics of erosion and resuspension, we have furthermore developed a grain-resolving simulation approach for representing the flow in the high-concentration region near and within the sediment bed. In these simulations, the Navier-Stokes flow around each particle and within the pore spaces of the sediment bed is resolved by means of an immersed boundary method, with the particle-particle interactions being taken into account via a detailed collision model. [Figure not available: see fulltext.

  6. High resolution computed tomography of auditory ossicles

    International Nuclear Information System (INIS)

    Isono, M.; Murata, K.; Ohta, F.; Yoshida, A.; Ishida, O.; Kinki Univ., Osaka

    1990-01-01

    Auditory ossicular sections were scanned at section thicknesses (mm)/section interspaces (mm) of 1.5/1.5 (61 patients), 1.0/1.0 (13 patients) or 1.5/1.0 (33 patients). At any type of section thickness/interspace, the malleal and incudal structures were observed with almost equal frequency. The region of the incudostapedial joint and each component part of the stapes were shown more frequently at a section interspace of 1.0 mm than at 1.5 mm. The visualization frequency of each auditory ossicular component on two or more serial sections was investigated. At a section thickness/section interspace of 1.5/1.5, the visualization rates were low except for large components such as the head of the malleus and the body of the incus, but at a slice interspace of 1.0 mm, they were high for most components of the auditory ossicles. (orig.)

  7. Do high-resolution convection-permitting experiments on Europe need to be driven by high resolution global runs?

    Science.gov (United States)

    Berthou, Segolene; Chan, Steven; Kendon, Elizabeth; Roberts, Malcolm; Lee, Robert; Vanniere, Benoit

    2017-04-01

    Challenges of getting appropriate climate-change scenarios over Europe both come from having a good representation of the synoptic systems reaching Europe and having a good-enough representation of local and orographic processes in Europe. Therefore we perform both the evaluation of the driving global model and its dynamical downscaling with a 2.2km regional model on the present day period, in the perspective of using this configuration in a future climate scenario. 20-year long atmosphere-only simulations with the Unified Model of the Met Office were run at different global resolutions (130km, 60km and 25km) and the highest resolution was chosen to give the boundaries of a European-wide convection permitting simulation with a 2.2km resolution. The synoptic situation of the different global resolutions are comparable in terms of latitudinal distribution of the jets and weather regimes but there is consistent improvement in the frequency of storms reaching Europe at 25km resolution. High resolution global runs therefore mainly show added value in the high-frequency synoptic drivers. Compared to high resolution precipitation datasets, the 25km resolution is showing good representation of winter precipitation distribution, although with too many days of moderate precipitation in Western Europe. It shows a dry bias in summer, consistent with a mean jet too north.

  8. Special Issue: The Silicon Age

    Science.gov (United States)

    Kittler, Martin; Yang, Deren

    2006-03-01

    The present issue of physica status solidi (a) contains a collection of articles about different aspects of current silicon research and applications, ranging from basic investigations of mono- and polycrystalline silicon materials and nanostructures to technologies for device fabrication in silicon photovoltaics, micro- and optoelectronics. Guest Editors are Martin Kittler and Deren Yang, the organizers of a recent Sino-German symposium held in Cottbus, Germany, 19-24 September 2005.The cover picture shows four examples of The Silicon Age: the structure of a thin film solar cell on low-cost SSP (silicon sheet from powder) substrate (upper left image) [1], a high-resolution transmission electron microscopy image and diffraction pattern of a single-crystalline Si nanowire (upper right) [2], a carrier lifetime map from an n-type multicrystalline silicon wafer after gettering by a grain boundary (lower left) [3], and a scanning acoustic microscopy image of a bonded 150 mm diameter wafer pair (upper right) [4].

  9. High spatial resolution compressed sensing (HSPARSE) functional MRI.

    Science.gov (United States)

    Fang, Zhongnan; Van Le, Nguyen; Choy, ManKin; Lee, Jin Hyung

    2016-08-01

    To propose a novel compressed sensing (CS) high spatial resolution functional MRI (fMRI) method and demonstrate the advantages and limitations of using CS for high spatial resolution fMRI. A randomly undersampled variable density spiral trajectory enabling an acceleration factor of 5.3 was designed with a balanced steady state free precession sequence to achieve high spatial resolution data acquisition. A modified k-t SPARSE method was then implemented and applied with a strategy to optimize regularization parameters for consistent, high quality CS reconstruction. The proposed method improves spatial resolution by six-fold with 12 to 47% contrast-to-noise ratio (CNR), 33 to 117% F-value improvement and maintains the same temporal resolution. It also achieves high sensitivity of 69 to 99% compared the original ground-truth, small false positive rate of less than 0.05 and low hemodynamic response function distortion across a wide range of CNRs. The proposed method is robust to physiological noise and enables detection of layer-specific activities in vivo, which cannot be resolved using the highest spatial resolution Nyquist acquisition. The proposed method enables high spatial resolution fMRI that can resolve layer-specific brain activity and demonstrates the significant improvement that CS can bring to high spatial resolution fMRI. Magn Reson Med 76:440-455, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

  10. Development of high-resolution detector module with depth of interaction identification for positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Niknejad, Tahereh, E-mail: tniknejad@lip.pt [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Pizzichemi, Marco [University of Milano-Bicocca (Italy); Stringhini, Gianluca [University of Milano-Bicocca (Italy); CERN, Geneve (Switzerland); Auffray, Etiennette [CERN, Geneve (Switzerland); Bugalho, Ricardo; Da Silva, Jose Carlos; Di Francesco, Agostino [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Ferramacho, Luis [PETsys Electronics, Oeiras (Portugal); Lecoq, Paul [CERN, Geneve (Switzerland); Leong, Carlos [PETsys Electronics, Oeiras (Portugal); Paganoni, Marco [University of Milano-Bicocca (Italy); Rolo, Manuel [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); INFN, Turin (Italy); Silva, Rui [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Silveira, Miguel [PETsys Electronics, Oeiras (Portugal); Tavernier, Stefaan [PETsys Electronics, Oeiras (Portugal); Vrije Universiteit Brussel (Belgium); Varela, Joao [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); CERN, Geneve (Switzerland); Zorraquino, Carlos [Biomedical Image Technologies Lab, Universidad Politécnica de Madrid (Spain); CIBER-BBN, Universidad Politécnica de Madrid (Spain)

    2017-02-11

    We have developed a Time-of-flight high resolution and commercially viable detector module for the application in small PET scanners. A new approach to depth of interaction (DOI) encoding with low complexity for a pixelated crystal array using a single side readout and 4-to-1 coupling between scintillators and photodetectors was investigated. In this method the DOI information is estimated using the light sharing technique. The detector module is a 1.53×1.53×15 mm{sup 3} matrix of 8×8 LYSO scintillator with lateral surfaces optically depolished separated by reflective foils. The crystal array is optically coupled to 4×4 silicon photomultipliers (SiPM) array and readout by a high performance front-end ASIC with TDC capability (50 ps time binning). The results show an excellent crystal identification for all the scintillators in the matrix, a timing resolution of 530 ps, an average DOI resolution of 5.17 mm FWHM and an average energy resolution of 18.29% FWHM. - Highlights: • A new method for DOI encoding for PET detectors based on light sharing is proposed. • A prototype module with LYSO scintillator matrix coupled to SiPMs array is produced. • The module has one side readout and 4-to-1 coupling between scintillators and SiPMs. • A compact TOF front-end ASIC is used. • Excellent performances are shown by the prototype module.

  11. O-space with high resolution readouts outperforms radial imaging.

    Science.gov (United States)

    Wang, Haifeng; Tam, Leo; Kopanoglu, Emre; Peters, Dana C; Constable, R Todd; Galiana, Gigi

    2017-04-01

    While O-Space imaging is well known to accelerate image acquisition beyond traditional Cartesian sampling, its advantages compared to undersampled radial imaging, the linear trajectory most akin to O-Space imaging, have not been detailed. In addition, previous studies have focused on ultrafast imaging with very high acceleration factors and relatively low resolution. The purpose of this work is to directly compare O-Space and radial imaging in their potential to deliver highly undersampled images of high resolution and minimal artifacts, as needed for diagnostic applications. We report that the greatest advantages to O-Space imaging are observed with extended data acquisition readouts. A sampling strategy that uses high resolution readouts is presented and applied to compare the potential of radial and O-Space sequences to generate high resolution images at high undersampling factors. Simulations and phantom studies were performed to investigate whether use of extended readout windows in O-Space imaging would increase k-space sampling and improve image quality, compared to radial imaging. Experimental O-Space images acquired with high resolution readouts show fewer artifacts and greater sharpness than radial imaging with equivalent scan parameters. Radial images taken with longer readouts show stronger undersampling artifacts, which can cause small or subtle image features to disappear. These features are preserved in a comparable O-Space image. High resolution O-Space imaging yields highly undersampled images of high resolution and minimal artifacts. The additional nonlinear gradient field improves image quality beyond conventional radial imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. A Very High Spatial Resolution Detector for Small Animal PET

    International Nuclear Information System (INIS)

    Kanai Shah, M.S.

    2007-01-01

    Positron Emission Tomography (PET) is an in vivo analog of autoradiography and has the potential to become a powerful new tool in imaging biological processes in small laboratory animals. PET imaging of small animals can provide unique information that can help in advancement of human disease models as well as drug development. Clinical PET scanners used for human imaging are bulky, expensive and do not have adequate spatial resolution for small animal studies. Hence, dedicated, low cost instruments are required for conducting small animal studies with higher spatial resolution than what is currently achieved with clinical as well as dedicated small animal PET scanners. The goal of the proposed project is to investigate a new all solid-state detector design for small animal PET imaging. Exceptionally high spatial resolution, good timing resolution, and excellent energy resolution are expected from the proposed detector design. The Phase I project was aimed at demonstrating the feasibility of producing high performance solid-state detectors that provide high sensitivity, spatial resolution, and timing characteristics. Energy resolution characteristics of the new detector were also investigated. The goal of the Phase II project is to advance the promising solid-state detector technology for small animal PET and determine its full potential. Detectors modules will be built and characterized and finally, a bench-top small animal PET system will be assembled and evaluated

  13. Compact and high-resolution optical orbital angular momentum sorter

    Directory of Open Access Journals (Sweden)

    Chenhao Wan

    2017-03-01

    Full Text Available A compact and high-resolution optical orbital angular momentum (OAM sorter is proposed and demonstrated. The sorter comprises a quadratic fan-out mapper and a dual-phase corrector positioned in the pupil plane and the Fourier plane, respectively. The optical system is greatly simplified compared to previous demonstrations of OAM sorting, and the performance in resolution and efficiency is maintained. A folded configuration is set up using a single reflective spatial light modulator (SLM to demonstrate the validity of the scheme. The two phase elements are implemented on the left and right halves of the SLM and connected by a right-angle prism. Experimental results demonstrate the high resolution of the compact OAM sorter, and the current limit in efficiency can be overcome by replacing with transmissive SLMs and removing the beam splitters. This novel scheme paves the way for the miniaturization and integration of high-resolution OAM sorters.

  14. Microbeam High Angular Resolution Diffraction Applied to Optoelectronic Devices

    International Nuclear Information System (INIS)

    Kazimirov, A.; Bilderback, D. H.; Sirenko, A. A.; Cai, Z.-H.; Lai, B.

    2007-01-01

    Collimating perfect crystal optics in a combination with the X-ray focusing optics has been applied to perform high angular resolution microbeam diffraction and scattering experiments on micron-size optoelectronic devices produced by modern semiconductor technology. At CHESS, we used capillary optics and perfect Si/Ge crystal(s) arrangement to perform X-ray standing waves, high angular-resolution diffraction and high resolution reciprocal space mapping analysis. At the APS, 2ID-D microscope beamline, we employed a phase zone plate producing a beam with the size of 240 nm in the horizontal plane and 350 nm in the vertical (diffraction) plane and a perfect Si (004) analyzer crystal to perform diffraction analysis of selectively grown InGaAsP and InGaAlAs-based waveguides with arc sec angular resolution

  15. Dielectric elastomers, with very high dielectric permittivity, based on silicone and ionic interpenetrating networks

    DEFF Research Database (Denmark)

    Yu, Liyun; Madsen, Frederikke Bahrt; Hvilsted, Søren

    2015-01-01

    permittivity and the Young's modulus of the elastomer. One system that potentially achieves this involves interpenetrating polymer networks (IPNs), based on commercial silicone elastomers and ionic networks from amino- and carboxylic acid-functional silicones. The applicability of these materials as DEs...... are obtained while dielectric breakdown strength and Young's modulus are not compromised. These good overall properties stem from the softening effect and very high permittivity of ionic networks – as high as ε′ = 7500 at 0.1 Hz – while the silicone elastomer part of the IPN provides mechanical integrity...

  16. Liquid Scintillation High Resolution Spectral Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Grau Carles, A.; Grau Malonda, A.

    2010-08-06

    The CIEMAT/NIST and the TDCR methods in liquid scintillation counting are based on the determination of the efficiency for total counting. This paper tries to expand these methods analysing the pulse-height spectrum of radionuclides. To reach this objective we have to generalize the equations used in the model and to analyse the influence of ionization and chemical quench in both spectra and counting efficiency. We present equations to study the influence of different photomultipliers response in systems with one, two or three photomultipliers. We study the effect of the electronic noise discriminator level in both spectra and counting efficiency. The described method permits one to study problems that up to now was not possible to approach, such as the high uncertainty in the standardization of pure beta-ray emitter with low energy when we apply the TDCR method, or the discrepancies in the standardization of some electron capture radionuclides, when the CIEMAT/NIST method is applied. (Author) 107 refs.

  17. High spectral resolution image of Barnacle Bill

    Science.gov (United States)

    1997-01-01

    The rover Sojourner's first target for measurement by the Alpha-Proton-Xray Spectrometer (APXS) was the rock named Barnacle Bill, located close to the ramp down which the rover made its egress from the lander. The full spectral capability of the Imager for Mars Pathfinder (IMP), consisting of 13 wavelength filters, was used to characterize the rock's surface. The measured area is relatively dark, and is shown in blue. Nearby on the rock surface, soil material is trapped in pits (shown in red).Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

  18. High resolution charmonium spectroscopy with antiprotons

    International Nuclear Information System (INIS)

    Seth, K.K.

    1989-01-01

    The ultimate goal of all physics is to understand the elementary interactions and their manifestations in nature. Remarkable success has been achieved in the understanding of the electromagnetic and weak interactions. However, similar success has eluded the understanding of the strong interactions. Quantum ChromoDynamics, QCD, is the attempt to construct an elementary theory of strong interactions patterned after the highly successful electroweak theory [1]. In this paper, it is claimed that QCD is the theory of strong interactions, and that: hadrons are color singlets made of quarks and antiquarks, each of three colors and (so far) three generations. (u.d), (s.c) and (b.t) and six flavors; the short range WCD interaction is correctly patterned after QED as that due to one-gluon exchange and therefore proportional to 1/r; the additional unique feature of QCD is confinement. It is well approximated by a linear confining potential proportional r. The fact of the matter is that none of the above assertions can be proved. They have to be checked against experimental observations

  19. Liquid Scintillation High Resolution Spectral Analysis

    International Nuclear Information System (INIS)

    Grau Carles, A.; Grau Malonda, A.

    2010-01-01

    The CIEMAT/NIST and the TDCR methods in liquid scintillation counting are based on the determination of the efficiency for total counting. This paper tries to expand these methods analysing the pulse-height spectrum of radionuclides. To reach this objective we have to generalize the equations used in the model and to analyse the influence of ionization and chemical quench in both spectra and counting efficiency. We present equations to study the influence of different photomultipliers response in systems with one, two or three photomultipliers. We study the effect of the electronic noise discriminator level in both spectra and counting efficiency. The described method permits one to study problems that up to now was not possible to approach, such as the high uncertainty in the standardization of pure beta-ray emitter with low energy when we apply the TDCR method, or the discrepancies in the standardization of some electron capture radionuclides, when the CIEMAT/NIST method is applied. (Author) 107 refs.

  20. FERMI: a digital Front End and Readout MIcrosystem for high resolution calorimetry

    International Nuclear Information System (INIS)

    Alexanian, H.; Appelquist, G.; Bailly, P.

    1995-01-01

    We present a digital solution for the front-end electronics of high resolution calorimeters at future colliders. It is based on analogue signal compression, high speed A/D converters, a fully programmable pipeline and a digital signal processing (DSP) chain with local intelligence and system supervision. This digital solution is aimed at providing maximal front-end processing power by performing waveform analysis using DSP methods. For the system integration of the multichannel device a multi-chip, silicon-on-silicon multi-chip module (MCM) has been adopted. This solution allows a high level of integration of complex analogue and digital functions, with excellent flexibility in mixing technologies for the different functional blocks. This type of multichip integration provides a high degree of reliability and programmability at both the function and the system level, with the additional possibility of customising the microsystem to detector-specific requirements. For enhanced reliability in high radiation environments, fault tolerance strategies, i.e. redundancy, reconfigurability, majority voting and coding for error detection and correction, are integrated into the design. ((orig.))

  1. High-Sensitivity Temperature-Independent Silicon Photonic Microfluidic Biosensors

    Science.gov (United States)

    Kim, Kangbaek

    Optical biosensors that can precisely quantify the presence of specific molecular species in real time without the need for labeling have seen increased use in the drug discovery industry and molecular biology in general. Of the many possible optical biosensors, the TM mode Si biosensor is shown to be very attractive in the sensing application because of large field amplitude on the surface and cost effective CMOS VLSI fabrication. Noise is the most fundamental factor that limits the performance of sensors in development of high-sensitivity biosensors, and noise reduction techniques require precise studies and analysis. One such example stems from thermal fluctuations. Generally SOI biosensors are vulnerable to ambient temperature fluctuations because of large thermo-optic coefficient of silicon (˜2x10 -4 RIU/K), typically requiring another reference ring and readout sequence to compensate temperature induced noise. To address this problem, we designed sensors with a novel TM-mode shallow-ridge waveguide that provides both large surface amplitude for bulk and surface sensing. With proper design, this also provides large optical confinement in the aqueous cladding that renders the device athermal using the negative thermo-optic coefficient of water (~ --1x10-4RIU/K), demonstrating cancellation of thermo-optic effects for aqueous solution operation near 300K. Additional limitations resulting from mechanical actuator fluctuations, stability of tunable lasers, and large 1/f noise of lasers and sensor electronics can limit biosensor performance. Here we also present a simple harmonic feedback readout technique that obviates the need for spectrometers and tunable lasers. This feedback technique reduces the impact of 1/f noise to enable high-sensitivity, and a DSP lock-in with 256 kHz sampling rate can provide down to micros time scale monitoring for fast transitions in biomolecular concentration with potential for small volume and low cost. In this dissertation, a novel

  2. Towards an optimum silicon heterojunction solar cell configuration for high temperature and high light intensity environment

    KAUST Repository

    Abdallah, Amir

    2017-09-22

    We report on the performance of Silicon Heterojunction (SHJ) solar cell under high operating temperature and varying irradiance conditions typical to desert environment. In order to define the best solar cell configuration that resist high operating temperature conditions, two different intrinsic passivation layers were tested, namely, an intrinsic amorphous silicon a-SiO:H with CO/SiH ratio of 0.4 and a-SiOx:H with CO/SiH ratio of 0.8, and the obtained performance were compared with those of a standard SHJ cell configuration having a-Si:H passivation layer. Our results showed how the short circuit current density J, and fill factor FF temperature-dependency are impacted by the cell\\'s configuration. While the short circuit current density J for cells with a-SiO:H layers was found to improve as compared with that of standard a-Si:H layer, introducing the intrinsic amorphous silicon oxide (a-SiO:H) layer with CO/SiH ratio of 0.8 has resulted in a reduction of the FF at room temperature due to hindering the carrier transport by the band structure. Besides, this FF was found to improve as the temperature increases from 15 to 45°C, thus, a positive FF temperature coefficient.

  3. TEM investigation of aluminium containing precipitates in high aluminium doped silicon carbide

    International Nuclear Information System (INIS)

    Wong-Leung, J.; FitzGerald, J.D.

    2002-01-01

    Full text: Silicon carbide is a promising semiconductor material for applications in high temperature and high power devices. The successful growth of good quality epilayers in this material has enhanced its potential for device applications. As a novel semiconductor material, there is a need for studying its basic physical properties and the role of dopants in this material. In this study, silicon carbide epilayers were grown on 4H-SiC wafers of (0001) orientation with a miscut angle of 8 deg at a temperature of 1550 deg C. The epilayers contained regions of high aluminium doping well above the solubility of aluminium in silicon carbide. High temperature annealing of this material resulted in the precipitation of aluminium in the wafers. The samples were analysed by secondary ion mass spectrometry and transmission electron microscopy. Selected area diffraction studies show the presence of aluminium carbide and aluminium silicon carbide phases. Copyright (2002) Australian Society for Electron Microscopy Inc

  4. Template-Growth of Highly Ordered Carbon Nanotube Arrays on Silicon POSTPRINT

    National Research Council Canada - National Science Library

    Yin, Aijun; Tzolov, Marian; Cardimona, David A; Xu, Jimmy

    2006-01-01

    .... The uniformity is ensured through the growth within the highly ordered nanopores or an alumina oxide template, which is in turn formed on silicon through anodization of aluminum of unprecedented...

  5. Development of Radiation Hard Radiation Detectors, Differences between Czochralski Silicon and Float Zone Silicon

    CERN Document Server

    Tuominen, Eija

    2012-01-01

    The purpose of this work was to develop radiation hard silicon detectors. Radiation detectors made ofsilicon are cost effective and have excellent position resolution. Therefore, they are widely used fortrack finding and particle analysis in large high-energy physics experiments. Silicon detectors willalso be used in the CMS (Compact Muon Solenoid) experiment that is being built at the LHC (LargeHadron Collider) accelerator at CERN (European Organisation for Nuclear Research). This work wasdone in the CMS programme of Helsinki Institute of Physics (HIP).Exposure of the silicon material to particle radiation causes irreversible defects that deteriorate theperformance of the silicon detectors. In HIP CMS Programme, our approach was to improve theradiation hardness of the silicon material with increased oxygen concentration in silicon material. Westudied two different methods: diffusion oxygenation of Float Zone silicon and use of high resistivityCzochralski silicon.We processed, characterised, tested in a parti...

  6. A multi-channel high-resolution time recorder system

    International Nuclear Information System (INIS)

    Zhang Lingyun; Yang Xiaojun; Song Kezhu; Wang Yanfang

    2004-01-01

    This paper introduces a multi-channel and high-speed time recorder system, which was originally designed to work in the experiments of quantum cryptography research. The novelty of the system is that all the hardware logic is performed by only one FPGA. The system can achieve several desirable features, such as simplicity, high resolution and high processing speed. (authors)

  7. Development of Silicon Sensor Characterization System for Future High Energy Physics Experiments

    OpenAIRE

    Preeti kumari; Kavita Lalwani; Ranjeet Dalal; Geetika Jain; Ashutosh Bhardwaj; Kirti Ranjan

    2015-01-01

    The Compact Muon Solenoid (CMS) is one of the general purpose experiments at the Large Hadron Collider (LHC), CERN and has its Tracker built of all silicon strip and pixel sensors. Si sensors are expected to play extremely important role in the upgrades of the existing Tracker for future high luminosity environment and will also be used in future lepton colliders. However, properties of the silicon sensors have to be carefully understood before they can be put in the extremely high luminos...

  8. Scaling of black silicon processing time by high repetition rate femtosecond lasers

    Directory of Open Access Journals (Sweden)

    Nava Giorgio

    2013-11-01

    Full Text Available Surface texturing of silicon substrates is performed by femtosecond laser irradiation at high repetition rates. Various fabrication parameters are optimized in order to achieve very high absorptance in the visible region from the micro-structured silicon wafer as compared to the unstructured one. A 70-fold reduction of the processing time is demonstrated by increasing the laser repetition rate from 1 kHz to 200 kHz. Further scaling up to 1 MHz can be foreseen.

  9. Dry Lubrication of High Temperature Silicon Nitride Rolling Contacts.

    Science.gov (United States)

    1980-11-01

    Ray Radiography A 150 mm x 15 mm x 3 mm slab was sliced from each HPSN billet received from Norton for this program. These sections were x-ray...that the micro- fissures did penetrate the silicon nitride, i.e., the microfis- sures were not confined to the thickness of the solid lubricant

  10. High-performance RF coil inductors on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Malba, V.; Young, D.; Ou, J.J.; Bernhardt, A.F.; Boser, B.E.

    1998-03-01

    Strong demand for wireless communication devices has motivated research directed toward monolithic integration of transceivers. The fundamental electronic component least compatible with silicon integrated circuits is the inductor, although a number of inductors are required to implement oscillators, filters and matching networks in cellular devices. Spiral inductors have been integrated into the silicon IC metallization sequence but have not performed adequately due to coupling to the silicon which results in parasitic capacitance and loss. We have, for the first time, fabricated three dimensional coil inductors on silicon which have significantly lower capacitive coupling and loss and which now exceed the requirements of potential applications. Quality factors of 30 at 1 GHz have been measured in single turn devices and Q > 16 in 2 and 4 turn devices. The reduced Q for multiturn devices appears to be related to eddy currents in outer turns generated by magnetic fields from current in neighboring turns. Higher Q values significantly in excess of 30 are anticipated using modified coil designs.

  11. Towards high-resolution retinal prostheses with direct optical addressing and inductive telemetry

    Science.gov (United States)

    Ha, Sohmyung; Khraiche, Massoud L.; Akinin, Abraham; Jing, Yi; Damle, Samir; Kuang, Yanjin; Bauchner, Sue; Lo, Yu-Hwa; Freeman, William R.; Silva, Gabriel A.; Cauwenberghs, Gert

    2016-10-01

    Objective. Despite considerable advances in retinal prostheses over the last two decades, the resolution of restored vision has remained severely limited, well below the 20/200 acuity threshold of blindness. Towards drastic improvements in spatial resolution, we present a scalable architecture for retinal prostheses in which each stimulation electrode is directly activated by incident light and powered by a common voltage pulse transferred over a single wireless inductive link. Approach. The hybrid optical addressability and electronic powering scheme provides separate spatial and temporal control over stimulation, and further provides optoelectronic gain for substantially lower light intensity thresholds than other optically addressed retinal prostheses using passive microphotodiode arrays. The architecture permits the use of high-density electrode arrays with ultra-high photosensitive silicon nanowires, obviating the need for excessive wiring and high-throughput data telemetry. Instead, the single inductive link drives the entire array of electrodes through two wires and provides external control over waveform parameters for common voltage stimulation. Main results. A complete system comprising inductive telemetry link, stimulation pulse demodulator, charge-balancing series capacitor, and nanowire-based electrode device is integrated and validated ex vivo on rat retina tissue. Significance. Measurements demonstrate control over retinal neural activity both by light and electrical bias, validating the feasibility of the proposed architecture and its system components as an important first step towards a high-resolution optically addressed retinal prosthesis.

  12. Diamond x-ray optics: Transparent, resilient, high-resolution, and wavefront preserving

    International Nuclear Information System (INIS)

    Shvyd’ko, Yuri; Blank, Vladimir; Terentyev, Sergey

    2017-01-01

    Diamond features a unique combination of outstanding physical properties perfect for numerous x-ray optics applications, where traditional materials such as silicon fail to perform. In the last two decades, impressive progress has been achieved in synthesizing diamond with high crystalline perfection, in manufacturing efficient, resilient, high-resolution, wavefront-preserving diamond optical components, and in implementing them in cutting-edge x-ray instruments. Diamond optics are essential for tailoring x-rays to the most challenging needs of x-ray research. Furthermore, they are becoming vital for the generation of fully coherent hard x-rays by seeded x-ray free-electron lasers. In this article, we review progress in manufacturing flawless diamond crystal components and their applications in diverse x-ray optical devices, such as x-ray monochromators, beam splitters, high-reflectance backscattering mirrors, lenses, phase plates, diffraction gratings, bent-crystal spectrographs, and windows.

  13. High resolution resistivity measurements at the Down Ampney research site

    International Nuclear Information System (INIS)

    Hallam, J.R.; Jackson, P.D.; Rainsbury, M.; Raines, M.

    1991-01-01

    A new high resolution resistivity surveying method is described for fault detection and characterisation. The resolution is shown to be significantly higher than conventional apparent resistivity profiling when applied to geological discontinuities such as faults. Nominal fault locations have been determined to an accuracy of 0.5 m, as proven by drilling. Two dimensional profiling and image enhancement of the resulting 2-D data set indicated the possibility of subsidiary fractures and/or lateral changes within the clay to clay' fault zone. The increased resolution allows greater confidence to be placed on both the fault detection and lateral perturbations derived from processed resistance and resistivity images. (Author)

  14. New detector developments for high resolution positron emission tomography

    International Nuclear Information System (INIS)

    Ziegler, S.I.; Pichler, B.; Lorenz, E.

    1998-01-01

    The strength of quantitative, functional imaging using positron emission tomography, specially in small animals, is limited due to the spatial resolution. Therefore, various tomograph designs employing new scintillators, light sensors, or coincidence electronic are investigated to improve resolution without losses in sensitivity. Luminous scintillators with short light decay time in combination with novel readout schemes using photomultipliers or semiconductor detectors are currently tested by several groups and are implemented in tomographs for small animals. This review summarises the state of development in high resolution positron emission tomography with a detailed description of a system incorporating avalanche photodiode arrays and small scintillation crystals. (orig.) [de

  15. Performance of a high resolution cavity beam position monitor system

    International Nuclear Information System (INIS)

    Walston, Sean; Boogert, Stewart; Chung, Carl; Fitsos, Pete; Frisch, Joe; Gronberg, Jeff; Hayano, Hitoshi; Honda, Yosuke; Kolomensky, Yury; Lyapin, Alexey; Malton, Stephen; May, Justin; McCormick, Douglas; Meller, Robert; Miller, David; Orimoto, Toyoko; Ross, Marc; Slater, Mark; Smith, Steve; Smith, Tonee; Terunuma, Nobuhiro; Thomson, Mark; Urakawa, Junji; Vogel, Vladimir; Ward, David; White, Glen

    2007-01-01

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than 1nm. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6nm and a tilt resolution of 2.1μrad over a dynamic range of approximately +/-20μm

  16. THz holography in reflection using a high resolution microbolometer array.

    Science.gov (United States)

    Zolliker, Peter; Hack, Erwin

    2015-05-04

    We demonstrate a digital holographic setup for Terahertz imaging of surfaces in reflection. The set-up is based on a high-power continuous wave (CW) THz laser and a high-resolution (640 × 480 pixel) bolometer detector array. Wave propagation to non-parallel planes is used to reconstruct the object surface that is rotated relative to the detector plane. In addition we implement synthetic aperture methods for resolution enhancement and compare Fourier transform phase retrieval to phase stepping methods. A lateral resolution of 200 μm and a relative phase sensitivity of about 0.4 rad corresponding to a depth resolution of 6 μm are estimated from reconstructed images of two specially prepared test targets, respectively. We highlight the use of digital THz holography for surface profilometry as well as its potential for video-rate imaging.

  17. Performance of a High Resolution Cavity Beam Position Monitor System

    Energy Technology Data Exchange (ETDEWEB)

    Walston, S; Boogert, S; Chung, C; Fitsos, P; Frisch, J; Gronberg, J; Hayano, H; Honda, Y; Kolomensky, Y; Lyapin, A; Malton, S; May, J; McCormick, D; Meller, R; Miller, D; Orimoto, T; Ross, M; Slater, M; Smith, S; Smith, T; Terunuma, N; Thomson, M; Urakawa, J; Vogel, V; Ward, D; White, G

    2006-12-18

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {micro}rad over a dynamic range of approximately {+-} 20 {micro}m.

  18. Performance of a High Resolution Cavity Beam Position Monitor System

    Energy Technology Data Exchange (ETDEWEB)

    Walston, Sean; Boogert, Stewart; Chung, Carl; Fitsos, Joe; Frisch, Joe; Gronberg, Jeff; Hayano, Hitoshi; Honda, Yosuke; Kolomensky, Yury; Lyapin, Alexey; Malton, Stephen; May, Justin; McCormick, Douglas; Meller, Robert; Miller, David John; Orimoto, Toyoko; Ross, Marc; Slater, Mark; Smith, Steve; Smith, Tonee; Terunuma, Nobuhiro; /Fermilab /UC,

    2007-06-08

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {mu}rad over a dynamic range of approximately {+-} 20 {mu}m.

  19. High-resolution spectroscopy of gases for industrial applications

    DEFF Research Database (Denmark)

    Fateev, Alexander; Clausen, Sønnik

    databases (e.g. HITRAN, HITEMP or CDSD) can normally be used for absorption spectra calculations at limited temperature/pressure ranges. Therefore experimental measurements of absorption/transmission spectra gases (e.g. CO2, H2O or SO2) at high-resolution and elevated temperatures are essential both......High-resolution spectroscopy of gases is a powerful technique which has various fundamental and practical applications: in situ simultaneous measurements of gas temperature and gas composition, radiative transfer modeling, validation of existing and developing of new databases and etc. Existing...... for analysis of complex experimental data and further development of the databases. High-temperature gas cell facilities available at DTU Chemical Engineering are presented and described. The gas cells and high-resolution spectrometers allow us to perform high-quality reference measurements of gases relevant...

  20. Detection of proximal caries with high-resolution and standard resolution digital radiographic systems.

    Science.gov (United States)

    Berkhout, W E R; Verheij, J G C; Syriopoulos, K; Li, G; Sanderink, G C H; van der Stelt, P F

    2007-05-01

    The aim of this study was to: (1) compare the diagnostic accuracy of the high-resolution and standard resolution settings of four digital imaging systems for caries diagnosis and (2) compare the effect on the diagnostic accuracy of reducing the high-resolution image sizes to the standard resolution dimensions, and vice versa. 90 extracted human premolars were mounted in groups of 5 in plaster blocks, containing 4 test teeth and 1 non-test tooth. Two blocks at a time were placed in a jig to simulate a bitewing radiograph. Radiographs were taken using four digital systems (Planmeca Dixi 2; Gendex Visualix HDI; Dürr Vistascan; Digora Optime), each at two resolution settings. Next, the teeth were sectioned and a total of 65 surfaces were incorporated in the study. Additionally, the bicubic interpolation method was applied to reduce the high-resolution original images and to enlarge the standard resolution images. The original, reduced and enlarged images were randomly shown to five observers in two random sessions. The observers were asked to assess caries depth on a 4-point scale. The observers' scores were compared with the results from a histological examination. Data were analysed using the statistical theory for multivariate discrete data. Cohen's kappa was used to determine the agreement with the gold standard. None of the comparisons between the spatial resolution settings, or the comparisons between increased or reduced image size and the original image sizes, showed significant differences in the probability of caries detection (chi2=26.59, df=26, P approximately 0.50). The four digital systems used in this study differ significantly in the probability of caries detection (chi2=41.55, df=24, PCaries diagnosis does not improve when using high-resolution settings compared with the standard settings. The use of bicubic convolution interpolation for zooming has no detectable effect on caries diagnosis and therefore is recommended to use when enlarging or reducing

  1. Feasibility of using experimental high viscosity silicone oils: a pilot study.

    Science.gov (United States)

    Sheen-Ophir, Shira; Rosner, Mordechai; Rubowitz, Alexander

    2018-01-01

    Polydimethyl silicones (silicone oils) are used in complex retinal surgeries, including difficult or recurrent retinal detachments, severe eye trauma, and other indications for long term tamponade. Two major problems with currently available silicone oils are emulsification and recurrent retinal detachment. The primary endpoint of this study was to evaluate the toxicity and safety of high viscosity silicone oils and second, the feasibility of using them with currently available vitrectomy systems. In this experimental study, 8 eyes of 8 New Zealand White rabbits underwent vitrectomy. The vitreous cavities of 2 eyes were filled with medical grade 5500 cS silicone oil, 4 eyes with 12,500 cS oil, and 2 eyes with 30,000 cS oil for 3 months, after which the animals were sacrificed and the eyes sent for histopathological examination. The duration required to inject 5 cc each of 1300, 12,500 and 30,000 cS oils, using a commercially available system (Alcon VFC Pac) were also evaluated. Retinal histopathology was comparable in all eyes, with no excess toxic effect or damage seen in eyes with experimental oils. All oils were readily injectable with the VFC Pac system. High viscosity experimental silicone oils have similar chemical and physical properties to lower viscosity oils currently used. Therefore, toxicities are expected to be similar. In a small pilot sample of 8 rabbit eyes filled with silicone oil for 3 months, histopathology in eyes with 12,500, 30,000 cS or medical grade 5500 cS silicone oil were similar. Injecting these oils using available vitrectomy equipment is feasible. New, high viscosity silicone oils may offer several advantages over currently available oils for some patients.

  2. Isotope specific resolution recovery image reconstruction in high resolution PET imaging.

    Science.gov (United States)

    Kotasidis, Fotis A; Angelis, Georgios I; Anton-Rodriguez, Jose; Matthews, Julian C; Reader, Andrew J; Zaidi, Habib

    2014-05-01

    Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution recovery image reconstruction. The

  3. Isotope specific resolution recovery image reconstruction in high resolution PET imaging

    International Nuclear Information System (INIS)

    Kotasidis, Fotis A.; Angelis, Georgios I.; Anton-Rodriguez, Jose; Matthews, Julian C.; Reader, Andrew J.; Zaidi, Habib

    2014-01-01

    Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution

  4. Ultra-high-speed wavelength conversion in a silicon photonic chip

    DEFF Research Database (Denmark)

    Hu, Hao; Ji, Hua; Galili, Michael

    2011-01-01

    We have successfully demonstrated all-optical wavelength conversion of a 640-Gbit/s line-rate return-to-zero differential phase-shift keying (RZ-DPSK) signal based on low-power four wave mixing (FWM) in a silicon photonic chip with a switching energy of only ~110 fJ/bit. The waveguide dispersion...... of the silicon nanowire is nano-engineered to optimize phase matching for FWM and the switching power used for the signal processing is low enough to reduce nonlinear absorption from twophoton- absorption (TPA). These results demonstrate that high-speed wavelength conversion is achievable in silicon chips...... with high data integrity and indicate that high-speed operation can be obtained at moderate power levels where nonlinear absorption due to TPA and free-carrier absorption (FCA) is not detrimental. This demonstration can potentially enable highspeed optical networks on a silicon photonic chip....

  5. Infrared emission high spectral resolution atlas of the stratospheric limb

    Science.gov (United States)

    Maguire, William C.; Kunde, Virgil G.; Herath, Lawrence W.

    1989-01-01

    An atlas of high resolution infrared emission spectra identifies a number of gaseous atmospheric features significant to stratospheric chemistry in the 770-900/cm and 1100-1360/cm regions at six zenith angles from 86.7 to 95.1 deg. A balloon-borne Michelson interferometer was flown to obtain about 0.03/cm resolution spectra. Two 10/cm extracts are presented here.

  6. High resolution scintillation hodoscope using a position sensitive photomultiplier

    International Nuclear Information System (INIS)

    Ditta, J.; Sillou, D.; Michalowicz, A.; Azaiez, H.; Kuroda, K.

    1983-09-01

    Using a position sensitive photomultiplier we have realized and tested a prototype of high resolution scintillation hodoscope. A space resolution of approximately 1 mm (FWHM) has been obtained by a single block of NE102A scintillator, 10 mm thick, with 10 GeV/c π - particles. An off-line analysis based on the moment method has confirmed the fact that suitable cuts in the second-order moments provides a powerful criterion for improving the image quality

  7. A high resolution TOF-PET concept with axial geometry and digital SiPM readout

    CERN Document Server

    Casella, C; Joram, C; Schneider, T

    2014-01-01

    The axial arrangement of long scintillation crystals is a promising concept in PET instrumentation to address the need for optimized resolution and sensitivity. Individual crystal readout and arrays of wavelength shifter strips placed orthogonally to the crystals lead to a 3D-detection of the annihilations photons. A fully operational demonstrator scanner, developed by the AX-PET collaboration, proved the potential of this concept in terms of energy and spatial resolution as well as sensitivity. This paper describes a feasibility study, performed on axial prototype detector modules with 100 mm long LYSO crystals, read out by the novel digital Silicon Photomultipliers (dSiPM) from Philips. With their highly integrated readout electronics and excellent intrinsic time resolution, dSiPMs allow for compact, axial detector modules which may extend the potential of the axial PET concept by time of fl ight capabilities (TOF-PET). A coincidence time resolution of 211 ps (FWHM) was achieved in the coincidence of two ax...

  8. Derivation of high spatial resolution albedo from UAV digital imagery: application over the Greenland Ice Sheet

    Science.gov (United States)

    Ryan, Jonathan C.; Hubbard, Alun; Box, Jason E.; Brough, Stephen; Cameron, Karen; Cook, Joseph M.; Cooper, Matthew; Doyle, Samuel H.; Edwards, Arwyn; Holt, Tom; Irvine-Fynn, Tristram; Jones, Christine; Pitcher, Lincoln H.; Rennermalm, Asa K.; Smith, Laurence C.; Stibal, Marek; Snooke, Neal

    2017-05-01

    Measurements of albedo are a prerequisite for modelling surface melt across the Earth's cryosphere, yet available satellite products are limited in spatial and/or temporal resolution. Here, we present a practical methodology to obtain centimetre resolution albedo products with accuracies of 5% using consumer-grade digital camera and unmanned aerial vehicle (UAV) technologies. Our method comprises a workflow for processing, correcting and calibrating raw digital images using a white reference target, and upward and downward shortwave radiation measurements from broadband silicon pyranometers. We demonstrate the method with a set of UAV sorties over the western, K-sector of the Greenland Ice Sheet. The resulting albedo product, UAV10A1, covers 280 km2, at a resolution of 20 cm per pixel and has a root-mean-square difference of 3.7% compared to MOD10A1 and 4.9% compared to ground-based broadband pyranometer measurements. By continuously measuring downward solar irradiance, the technique overcomes previous limitations due to variable illumination conditions during and between surveys over glaciated terrain. The current miniaturization of multispectral sensors and incorporation of upward facing radiation sensors on UAV packages means that this technique will likely become increasingly attractive in field studies and used in a wide range of applications for high temporal and spatial resolution surface mapping of debris, dust, cryoconite and bioalbedo and for directly constraining surface energy balance models.

  9. Relaxation of the Shallow Acceptor Center Magnetic Moment in a Highly Doped Silicon

    CERN Document Server

    Mamedov, T N; Herlach, D; Gorelkin, V N; Gritsaj, K I; Duginov, V N; Kormann, O; Major, J V; Stoikov, A V; Zimmermann, U

    2001-01-01

    Results on the temperature dependence of the residual polarization of negative muons in crystalline silicon with germanium, boron and phosphorus impurities are presented. The measurements were carried out in a magnetic field of 0.1 T transverse to the direction of the muon spin in the temperature range 4.2-300 K. It is found that in a silicon sample with a high concentration of germanium impurity (9\\cdot 10^{19} cm^{-3}), as in the samples of n- and p-type silicon with impurity concentrations up to \\sim 10^{17} cm^{-3}, the relaxation rate \

  10. Fully-depleted, back-illuminated charge-coupled devices fabricated on high-resistivity silicon

    Energy Technology Data Exchange (ETDEWEB)

    Holland, Stephen E.; Groom, Donald E.; Palaio, Nick P.; Stover, Richard J.; Wei, Mingzhi

    2002-03-28

    Charge-coupled devices (CCD's) have been fabricated on high-resistivity silicon. The resistivity, on the order of 10,000 {Omega}-cm, allows for depletion depths of several hundred microns. Fully-depleted, back-illuminated operation is achieved by the application of a bias voltage to a ohmic contact on the wafer back side consisting of a thin in-situ doped polycrystalline silicon layer capped by indium tin oxide and silicon dioxide. This thin contact allows for good short wavelength response, while the relatively large depleted thickness results in good near-infrared response.

  11. Fabrication of a high-temperature microreactor with integrated heater and sensor patterns on an ultrathin silicon membrane

    NARCIS (Netherlands)

    Tiggelaar, Roald M.; Berenschot, Johan W.; van Male, P.; Oosterbroek, R.E.; Gardeniers, Johannes G.E.; de Croon, M.H.J.M.; Schouten, J.C.; van den Berg, Albert; Elwenspoek, Michael Curt

    2005-01-01

    In this paper critical steps in the fabrication process of a microreactor for high-temperature catalytic partial oxidation gas phase reactions are evaluated. The microreactor contains a flow channel etched in silicon, capped with an ultrathin composite membrane consisting of silicon and silicon

  12. Evolution of arsenic in high fluence plasma immersion ion implanted silicon : Behavior of the as-implanted surface

    NARCIS (Netherlands)

    Vishwanath, V.; Demenev, E.; Giubertoni, D.; Vanzetti, L.; Koh, A. L.; Steinhauser, G.; Pepponi, G.; Bersani, M.; Meirer, F.; Foad, M. A.

    2015-01-01

    High fluence (>1015 ions/cm2) low-energy (3 + on (1 0 0) silicon was investigated, with the focus on stability and retention of the dopant. At this dose, a thin (∼3 nm) amorphous layer forms at the surface, which contains about 45% arsenic (As) in a silicon and oxygen matrix. The presence of silicon

  13. Development of high performance readout ASICs for silicon photomultipliers (SiPMs)

    International Nuclear Information System (INIS)

    Shen, Wei

    2012-01-01

    Silicon Photomultipliers (SiPMs) are novel kind of solid state photon detectors with extremely high photon detection resolution. They are composed of hundreds or thousands of avalanche photon diode pixels connected in parallel. These avalanche photon diodes are operated in Geiger Mode. SiPMs have the same magnitude of multiplication gain compared to the conventional photomultipliers (PMTs). Moreover, they have a lot of advantages such as compactness, relatively low bias voltage and magnetic field immunity etc. Special readout electronics are required to preserve the high performance of the detector. KLauS and STiC are two CMOS ASIC chips designed in particular for SiPMs. KLauS is used for SiPM charge readout applications. Since SiPMs have a much larger detector capacitance compared to other solid state photon detectors such as PIN diodes and APDs, a few special techniques are used inside the chip to make sure a descent signal to noise ratio for pixel charge signal can be obtained. STiC is a chip dedicated to SiPM time-of-flight applications. High bandwidth and low jitter design schemes are mandatory for such applications where time jitter less than tens of picoseconds is required. Design schemes and error analysis as well as measurement results are presented in the thesis.

  14. High-Responsivity Graphene–Boron Nitride Photodetector and Autocorrelator in a Silicon Photonic Integrated Circuit

    Energy Technology Data Exchange (ETDEWEB)

    Shiue, Ren-Jye; Gao, Yuanda; Wang, Yifei; Peng, Cheng; Robertson, Alexander D.; Efetov, Dmitri K.; Assefa, Solomon; Koppens, Frank H. L.; Hone, James; Englund, Dirk

    2015-11-11

    Graphene and other two-dimensional (2D) materials have emerged as promising materials for broadband and ultrafast photodetection and optical modulation. These optoelectronic capabilities can augment complementary metal–oxide–semiconductor (CMOS) devices for high-speed and low-power optical interconnects. Here, we demonstrate an on-chip ultrafast photodetector based on a two-dimensional heterostructure consisting of high-quality graphene encapsulated in hexagonal boron nitride. Coupled to the optical mode of a silicon waveguide, this 2D heterostructure-based photodetector exhibits a maximum responsivity of 0.36 A/W and high-speed operation with a 3 dB cutoff at 42 GHz. From photocurrent measurements as a function of the top-gate and source-drain voltages, we conclude that the photoresponse is consistent with hot electron mediated effects. At moderate peak powers above 50 mW, we observe a saturating photocurrent consistent with the mechanisms of electron–phonon supercollision cooling. This nonlinear photoresponse enables optical on-chip autocorrelation measurements with picosecond-scale timing resolution and exceptionally low peak powers.

  15. Validation of High-resolution Climate Simulations over Northern Europe.

    Science.gov (United States)

    Muna, R. A.

    2005-12-01

    Two AMIP2-type (Gates 1992) experiments have been performed with climate versions of ARPEGE/IFS model examine for North Atlantic North Europe, and Norwegian region and analyzed the effect of increasing resolution on the simulated biases. The ECMWF reanalysis or ERA-15 has been used to validate the simulations. Each of the simulations is an integration of the period 1979 to 1996. The global simulations used observed monthly mean sea surface temperatures (SST) as lower boundary condition. All aspects but the horizontal resolutions are similar in the two simulations. The first simulation has a uniform horizontal resolution of T63L. The second one has a variable resolution (T106Lc3) with the highest resolution in the Norwegian Sea. Both simulations have 31 vertical layers in the same locations. For each simulation the results were divided into two seasons: winter (DJF) and summer (JJA). The parameters investigated were mean sea level pressure, geopotential and temperature at 850 hPa and 500 hPa. To find out the causes of temperature bias during summer, latent and sensible heat flux, total cloud cover and total precipitation were analyzed. The high-resolution simulation exhibits more or less realistic climate over Nordic, Artic and European region. The overall performance of the simulations shows improvements of generally all fields investigated with increasing resolution over the target area both in winter (DJF) and summer (JJA).

  16. Automated data processing of high-resolution mass spectra

    DEFF Research Database (Denmark)

    Hansen, Michael Adsetts Edberg; Smedsgaard, Jørn

    infusion of crude extracts into the source taking advantage of the high sensitivity, high mass resolution and accuracy and the limited fragmentation. Unfortunately, there has not been a comparable development in the data processing techniques to fully exploit gain in high resolution and accuracy...... infusion analyses of crude extract to find the relationship between species from several species terverticillate Penicillium, and also that the ions responsible for the segregation can be identified. Furthermore the process can automate the process of detecting unique species and unique metabolites....

  17. Soft Tissue Foreign Body: Utility of High Resolution Ultrasonography

    Science.gov (United States)

    Reddy, Harish; Ibrahim, Jebin; Haritha, CH; Shah, Rushit Sandeep

    2017-01-01

    Introduction Minor percentage of wooden foreign bodies is radio-opaque. High Resolution Ultrasonography (HRUSG) though existing is sparsely used as a primary imaging modality for diagnosis and localization of retained foreign body. Aim To evaluate the diagnostic accuracy of High Resolution Ultrasonography (HRUSG) in diagnoses and localization of retained foreign body. Materials and Methods A prospective study with registered 46 patients with history of foreign body injury which were initially imaged with conventional radiography was enrolled. Later patients were subjected for high resolution USG of the diseased part with a linear transducer. Surface marking was done for all subjects to assist the surgical exploration. Ultrasound findings were correlated with surgical exploration and histopathological findings. Results Out of 46 patients, forty one showed foreign body with foreign body inflammatory reaction in the form of abscess and/or granulation tissue on high resolution ultrasonography. No foreign body was detected in five patients but they showed focal hypoechogenicity which represented abscess and/or haematoma. On surgical exploration, two out of 41 patients did not reveal foreign body where as rest were found to have foreign body with foreign body inflammatory reaction. Sensitivity and negative predictive value of the current study is 100%. Conclusion High resolution USG is not only an efficient modality in diagnosing and localizing the foreign body in soft tissue, but can also be utilized for guiding the foreign body removal. PMID:28892999

  18. Design and performance of a high rate, high angular resolution beam telescope used for crystal channeling studies

    International Nuclear Information System (INIS)

    Pesaresi, M; Ferguson, W; Fulcher, J; Hall, G; Raymond, M; Ryan, M; Zorba, O

    2011-01-01

    A charged particle telescope has been constructed for data taking at high rates in a CERN 400 GeV/c proton beam line. It utilises ten planes of silicon microstrip sensors, arranged as five pairs each measuring two orthogonal coordinates, with an active area of 3.8 x 3.8 cm 2 . The objective was to provide excellent angular and spatial resolution for measuring the trajectories of incident and outgoing particles. The apparatus has a long baseline, of approximately 10 m in each arm, and achieves an angular resolution in the incoming arm of 2.8 μrad and a total angular resolution on the difference of the two arms of 5.2 μrad, with performance limited by multiple scattering in the sensor layers. The sensors are instrumented by a system based on the CMS Tracker electronic readout chain, including analogue signal readout for optimal spatial resolution. The system profits from modified CMS software and hardware to provide a data acquisition capable of peak trigger rates of at least 7 kHz. We describe the sensor readout, electronic hardware and software, together with the measured performance of the telescope during studies of crystal channeling for the UA9 collaboration. Measurements of a previously unobserved periodic movement of the beam are also presented and the significance of such an effect for precise studies such as for channeling is discussed.

  19. A high resolution powder diffractometer using focusing optics

    Indian Academy of Sciences (India)

    sample environment of very low temperatures and high magnetic fields using a 7 Tesla cryogen-free superconducting magnet with a VTI having a temperature range of 1.5–. 320 K. The special sample environment and high resolution make this neutron powder diffractometer a very powerful facility for studying magnetic ...

  20. Comparison of High Resolution Negative Electron Beam Resists

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Schøler, Mikkel; Shi, Peixiong

    2006-01-01

    Four high resolution negative electron beam resists are compared: TEBN-1 from Tokuyama Corp. Japan, ma-N 2401XP and mr-L 6000AXP from microresist technology GmbH Germany, and SU-8 2000 series from MicroChem Corp., USA. Narrow linewidth high density patterns are defined by 100 kV electron beam...

  1. A high resolution powder diffractometer using focusing optics

    Indian Academy of Sciences (India)

    The instrument provides sample environment of very low temperatures and high magnetic fields using a 7 Tesla cryogen-free superconducting magnet with a VTI having a temperature range of 1.5–320 K. The special sample environment and high resolution make this neutron powder diffractometer a very powerful facility for ...

  2. Stars and planets at high spatial and spectral resolution

    NARCIS (Netherlands)

    Albrecht, Simon

    2008-01-01

    The work presented in this thesis involves the development of new instrumental techniques and analysing tools, combining high spectral resolution with high spatial information, with the aim to increase our understanding of the formation and evolution of stars and planets. First, a novel instrumental

  3. High-precision X-ray spectroscopy of highly-charged ions at the experimental storage ring using silicon microcalorimeters

    Science.gov (United States)

    Scholz, Pascal A.; Andrianov, Victor; Echler, Artur; Egelhof, Peter; Kilbourne, Caroline; Kiselev, Oleg; Kraft-Bermuth, Saskia; McCammon, Dan

    2017-10-01

    X-ray spectroscopy on highly charged heavy ions provides a sensitive test of quantum electrodynamics in very strong Coulomb fields. One limitation of the current accuracy of such experiments is the energy resolution of available X-ray detectors for energies up to 100 keV. To improve this accuracy, a novel detector concept, namely the concept of microcalorimeters, is exploited for this kind of measurements. The microcalorimeters used in the present experiments consist of silicon thermometers, ensuring a high dynamic range, and of absorbers made of high-Z material to provide high X-ray absorption efficiency. Recently, besides an earlier used detector, a new compact detector design, housed in a new dry cryostat equipped with a pulse tube cooler, was applied at a test beamtime at the experimental storage ring (ESR) of the GSI facility in Darmstadt. A U89+ beam at 75 MeV/u and a 124Xe54+ beam at various beam energies, both interacting with an internal gas-jet target, were used in different cycles. This test was an important benchmark for designing a larger array with an improved lateral sensitivity and statistical accuracy.

  4. High temperature mechanical performance of a hot isostatically pressed silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, A.A.; Ferber, M.K.; Jenkins, M.G.; Lin, C.K.J. [and others

    1996-01-01

    Silicon nitride ceramics are an attractive material of choice for designers and manufacturers of advanced gas turbine engine components for many reasons. These materials typically have potentially high temperatures of usefulness (up to 1400{degrees}C), are chemically inert, have a relatively low specific gravity (important for inertial effects), and are good thermal conductors (i.e., resistant to thermal shock). In order for manufacturers to take advantage of these inherent properties of silicon nitride, the high-temperature mechanical performance of the material must first be characterized. The mechanical response of silicon nitride to static, dynamic, and cyclic conditions at elevated temperatures, along with reliable and representative data, is critical information that gas turbine engine designers and manufacturers require for the confident insertion of silicon nitride components into gas turbine engines. This final report describes the high-temperature mechanical characterization and analyses that were conducted on a candidate structural silicon nitride ceramic. The high-temperature strength, static fatigue (creep rupture), and dynamic and cyclic fatigue performance were characterized. The efforts put forth were part of Work Breakdown Structure Subelement 3.2.1, {open_quotes}Rotor Data Base Generation.{close_quotes} PY6 is comparable to other hot isostatically pressed (HIPed) silicon nitrides currently being considered for advanced gas turbine engine applications.

  5. High resolution, position sensitive detector for energetic particle beams

    International Nuclear Information System (INIS)

    Marsh, E.P.; Strathman, M.D.; Reed, D.A.; Odom, R.W.; Morse, D.H.; Pontau, A.E.

    1993-01-01

    The performance and design of an imaging position sensitive, particle beam detector will be presented. The detector is minimally invasive, operates a wide dynamic range (>10 10 ), and exhibits high spatial resolution. The secondary electrons produced when a particle beam passes through a thin foil are imaged using stigmatic ion optics onto a two-dimensional imaging detector. Due to the low scattering cross section of the 6 nm carbon foil the detector is a minimal perturbation on the primary beam. A prototype detector with an image resolution of approximately 5 μm for a field of view of 1 mm has been reported. A higher resolution detector for imaging small beams (<50 μm) with an image resolution of better than 0.5 μm has since been developed and its design is presented. (orig.)

  6. Impurity effects in silicon for high efficiency solar cells

    Science.gov (United States)

    Hopkins, R. H.; Rohatgi, A.

    1986-01-01

    Model analyses indicate that sophisticated solar cell designs including, e.g., back surface fields, optical reflectors, surface passivation, and double layer antireflective coatings can produce devices with conversion efficiencies above 20 percent (AM1). To realize this potential, the quality of the silicon from which the cells are made must be improved; and these excellent electrical properties must be maintained during device processing. As the cell efficiency rises, the sensitivity to trace contaminants also increases. For example, the threshold Ti impurity concentration at which cell performance degrades is more than an order of magnitude lower for an 18-percent cell. Similar behavior occurs for numerous other metal species which introduce deep level traps that stimulate the recombination of photogenerated carriers in silicon. Purification via crystal growth in conjunction with gettering steps to preserve the large diffusion length of the as-grown material can lead to the production of devices with efficiencies aboved 18 percent, as has been verified experimentally.

  7. High-Resolution Spin-on-Patterning of Perovskite Thin Films for a Multiplexed Image Sensor Array.

    Science.gov (United States)

    Lee, Woongchan; Lee, Jongha; Yun, Huiwon; Kim, Joonsoo; Park, Jinhong; Choi, Changsoon; Kim, Dong Chan; Seo, Hyunseon; Lee, Hakyong; Yu, Ji Woong; Lee, Won Bo; Kim, Dae-Hyeong

    2017-10-01

    Inorganic-organic hybrid perovskite thin films have attracted significant attention as an alternative to silicon in photon-absorbing devices mainly because of their superb optoelectronic properties. However, high-definition patterning of perovskite thin films, which is important for fabrication of the image sensor array, is hardly accomplished owing to their extreme instability in general photolithographic solvents. Here, a novel patterning process for perovskite thin films is described: the high-resolution spin-on-patterning (SoP) process. This fast and facile process is compatible with a variety of spin-coated perovskite materials and perovskite deposition techniques. The SoP process is successfully applied to develop a high-performance, ultrathin, and deformable perovskite-on-silicon multiplexed image sensor array, paving the road toward next-generation image sensor arrays. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Low-Cost, High Efficiency, Silicon Based Photovoltaic Devices

    Science.gov (United States)

    2015-08-27

    solar cell (see Figure 6(b)). Metallic particles with sizes of a few tens of nanometers show resonant plasmon excitations, which lead to strong local... which propagate along the metal surface. Thus the vertical incident light is turned by 90º into a plasmonic mode that propagates in the horizontal...material in the photovoltaic industry. Silicon is nontoxic and relatively abundant in the earth’s crust , and therefore avoids any scarcity issues

  9. High-efficient n-i-p thin-film silicon solar cells

    NARCIS (Netherlands)

    Yang, G.

    2015-01-01

    In this thesis we present results of the development of n-i-p thin-film silicon solar cells on randomly textured substrates, aiming for highly efficient micromorph solar cells (i.e., solar cells based on a ?c-Si:H bottom cell and a-Si:H top cell). For the efficiency of n-i-p thin-film silicon solar

  10. Electronic GaAs-on-Silicon Material for Advanced High-Speed Optoelectronic Devices

    Science.gov (United States)

    1991-01-01

    award under the Small Business Innovation Research (SBIR) program. The contract ran from August 1988 to August 1990. The project manager was Mr. James B...Matyi, and H. Shichijo, "Growth and Characterization of LPE GaAs on GaAs-coated Si Prepared by MBE," Heteroepitaxy on Silicon: Fundamantals , Structure...heteroepitaxy, high-speed LEDs, and liquid-phase electroepitaxy of silicon and III-V compound semiconductors. James B. McNeely was the Project Manager (August

  11. High spatial resolution diffusion tensor imaging and its applications

    CERN Document Server

    Wang, J J

    2002-01-01

    Introduction Magnetic Resonance Imaging is at present the only imaging technique available to measure diffusion of water and metabolites in humans. It provides vital insights to brain connectivity and has proved to be an important tool in diagnosis and therapy planning in many neurological diseases such as brain tumour, ischaemia and multiple sclerosis. This project focuses on the development of a high resolution diffusion tensor imaging technique. In this thesis, the basic theory of diffusion tensor MR Imaging is presented. The technical challenges encountered during development of these techniques will be discussed, with proposed solutions. New sequences with high spatial resolution have been developed and the results are compared with the standard technique more commonly used. Overview The project aims at the development of diffusion tensor imaging techniques with a high spatial resolution. Chapter 2 will describe the basic physics of MRI, the phenomenon of diffusion and the measurement of diffusion by MRI...

  12. High-resolution investigations of edge effects in neutron imaging

    International Nuclear Information System (INIS)

    Strobl, M.; Kardjilov, N.; Hilger, A.; Kuehne, G.; Frei, G.; Manke, I.

    2009-01-01

    Edge enhancement is the main effect measured by the so-called inline or propagation-based neutron phase contrast imaging method. The effect has originally been explained by diffraction, and high spatial coherence has been claimed to be a necessary precondition. However, edge enhancement has also been found in conventional imaging with high resolution. In such cases the effects can produce artefacts and hinder quantification. In this letter the edge effects at cylindrical shaped samples and long straight edges have been studied in detail. The enhancement can be explained by refraction and total reflection. Using high-resolution imaging, where spatial resolutions better than 50 μm could be achieved, refraction and total reflection peaks - similar to diffraction patterns - could be separated and distinguished.

  13. High-resolution low-dose scanning transmission electron microscopy.

    Science.gov (United States)

    Buban, James P; Ramasse, Quentin; Gipson, Bryant; Browning, Nigel D; Stahlberg, Henning

    2010-01-01

    During the past two decades instrumentation in scanning transmission electron microscopy (STEM) has pushed toward higher intensity electron probes to increase the signal-to-noise ratio of recorded images. While this is suitable for robust specimens, biological specimens require a much reduced electron dose for high-resolution imaging. We describe here protocols for low-dose STEM image recording with a conventional field-emission gun STEM, while maintaining the high-resolution capability of the instrument. Our findings show that a combination of reduced pixel dwell time and reduced gun current can achieve radiation doses comparable to low-dose TEM.

  14. High spatial resolution CT image reconstruction using parallel computing

    International Nuclear Information System (INIS)

    Yin Yin; Liu Li; Sun Gongxing

    2003-01-01

    Using the PC cluster system with 16 dual CPU nodes, we accelerate the FBP and OR-OSEM reconstruction of high spatial resolution image (2048 x 2048). Based on the number of projections, we rewrite the reconstruction algorithms into parallel format and dispatch the tasks to each CPU. By parallel computing, the speedup factor is roughly equal to the number of CPUs, which can be up to about 25 times when 25 CPUs used. This technique is very suitable for real-time high spatial resolution CT image reconstruction. (authors)

  15. \\HIGH RESOLUTION 3D MODELING OF THE BEHAIM GLOBE

    Directory of Open Access Journals (Sweden)

    F. Menna

    2012-07-01

    Full Text Available The article describes the 3D surveying and modeling of the Behaim globe, the oldest still existing and intact globe of the earth, preserved at the German National Museum of Nuremberg, Germany. The work is primarily performed using high-resolution digital images and automatic photogrammetric techniques. Triangulation-based laser scanning is also employed to fill some gaps in the derived image-based 3D geometry and perform geometric comparisons. Major problems are encountered in texture mapping. The 3D modeling project and the creation of high-resolution map-projections is performed for scientific, conservation, visualization and education purposes.

  16. Progress in high-resolution x-ray holographic microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, C.; Kirz, J.; Howells, M.; McQuaid, K.; Rothman, S.; Feder, R.; Sayre, D.

    1987-07-01

    Among the various types of x-ray microscopes that have been demonstrated, the holographic microscope has had the largest gap between promise and performance. The difficulties of fabricating x-ray optical elements have led some to view holography as the most attractive method for obtaining the ultimate in high resolution x-ray micrographs; however, we know of no investigations prior to 1987 that clearly demonstrated submicron resolution in reconstructed images. Previous efforts suffered from problems such as limited resolution and dynamic range in the recording media, low coherent x-ray flux, and aberrations and diffraction limits in visible light reconstruction. We have addressed the recording limitations through the use of an undulator x-ray source and high-resolution photoresist recording media. For improved results in the readout and reconstruction steps, we have employed metal shadowing and transmission electron microscopy, along with numerical reconstruction techniques. We believe that this approach will allow holography to emerge as a practical method of high-resolution x-ray microscopy. 30 refs., 4 figs.

  17. Design and Fabrication of Two-Dimensional Semiconducting Bolometer Arrays for the High Resolution Airborne Wideband Camera (HAWC) and the Submillimeter High Angular Resolution Camera II (SHARC-II)

    Science.gov (United States)

    Voellmer, George M.; Allen, Christine A.; Amato, Michael J.; Babu, Sachidananda R.; Bartels, Arlin E.; Benford, Dominic J.; Derro, Rebecca J.; Dowell, C. Darren; Harper, D. Al; Jhabvala, Murzy D.

    2002-01-01

    The High resolution Airborne Wideband Camera (HAWC) and the Submillimeter High Angular Resolution Camera II (SHARC II) will use almost identical versions of an ion-implanted silicon bolometer array developed at the National Aeronautics and Space Administration's Goddard Space Flight Center (GSFC). The GSFC 'Pop-up' Detectors (PUD's) use a unique folding technique to enable a 12 x 32-element close-packed array of bolometers with a filling factor greater than 95 percent. A kinematic Kevlar(trademark) suspension system isolates the 200 mK bolometers from the helium bath temperature, and GSFC - developed silicon bridge chips make electrical connection to the bolometers, while maintaining thermal isolation. The JFET preamps operate at 120 K. Providing good thermal heat sinking for these, and keeping their conduction and radiation from reaching the nearby bolometers, is one of the principal design challenges encountered. Another interesting challenge is the preparation of the silicon bolometers. They are manufactured in 32-element, planar rows using Micro Electro Mechanical Systems (MEMS) semiconductor etching techniques, and then cut and folded onto a ceramic bar. Optical alignment using specialized jigs ensures their uniformity and correct placement. The rows are then stacked to create the 12 x 32-element array. Engineering results from the first light run of SHARC II at the Caltech Submillimeter Observatory (CSO) are presented.

  18. Multi-resolution voxel phantom modeling: a high-resolution eye model for computational dosimetry.

    Science.gov (United States)

    Caracappa, Peter F; Rhodes, Ashley; Fiedler, Derek

    2014-09-21

    Voxel models of the human body are commonly used for simulating radiation dose with a Monte Carlo radiation transport code. Due to memory limitations, the voxel resolution of these computational phantoms is typically too large to accurately represent the dimensions of small features such as the eye. Recently reduced recommended dose limits to the lens of the eye, which is a radiosensitive tissue with a significant concern for cataract formation, has lent increased importance to understanding the dose to this tissue. A high-resolution eye model is constructed using physiological data for the dimensions of radiosensitive tissues, and combined with an existing set of whole-body models to form a multi-resolution voxel phantom, which is used with the MCNPX code to calculate radiation dose from various exposure types. This phantom provides an accurate representation of the radiation transport through the structures of the eye. Two alternate methods of including a high-resolution eye model within an existing whole-body model are developed. The accuracy and performance of each method is compared against existing computational phantoms.

  19. Remote Measurements of the Atmosphere with High Spatial Resolution

    Science.gov (United States)

    Weinman, J. A.; Marzano, F. S.; Mugnai, A.

    2009-09-01

    Global atmosphere-ocean models are now operating at 3.5 km resolution and mesoscale weather prediction models operating at 1.7 km resolution have been used for the analysis of hurricanes. One can expect that weather prediction models will operate at resolutions better than 5 km during the coming decade. Microwave sensors have contributed valuable information about rainfall and sea surface winds. The Precipitation Radar (PR) onboard the Tropical Rainfall Measuring Mission (TRMM) can address this need. However it may be nearing the end of its life, and its replacement by the Global Precipitation Measurement (GPM) mission is expected no earlier than 2013. Recently the four Italian Cosmo-SkyMed, and the German Terra-SAR X-band synthetic aperture radars (SAR’s) have displayed rain distributions with resolution better than 0.5 km. The Quickscat also now provides distributions of rainfall and sea surface winds with 2.5 km resolution. We will describe rainfall retrieval algorithms, show rainfall distributions retrieved from Terra-SAR, and discuss errors in those measurements. We will also describe multi-frequency radar measurements of sea surface winds and rainfall during hurricanes. Although most remotely sensed rainfall and wind data can be expected to be obtained from satellites, unmanned aerial vehicles (UAV’s) with one week cruising duration and ~180 kg payloads flying at 18 km height may become attractive platforms from which severe weather can be tracked with high resolution.

  20. Preparation of highly aligned silicon oxide nanowires with stable intensive photoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Duraia, El-Shazly M., E-mail: duraia_physics@yahoo.co [Suez Canal University, Faculty of Science, Physics Department, Ismailia (Egypt); Al-Farabi Kazakh National University, Almaty (Kazakhstan); Institute of Physics and Technology, 11 Ibragimov Street, 050032 Almaty (Kazakhstan); Mansurov, Z.A. [Al-Farabi Kazakh National University, Almaty (Kazakhstan); Tokmolden, S. [Institute of Physics and Technology, 11 Ibragimov Street, 050032 Almaty (Kazakhstan); Beall, Gary W. [Texas State University-San Marcos, Department of Chemistry and Biochemistry, 601 University Dr., San Marcos, TX 78666 (United States)

    2010-02-15

    In this work we report the successful formation of highly aligned vertical silicon oxide nanowires. The source of silicon was from the substrate itself without any additional source of silicon. X-ray measurement demonstrated that our nanowires are amorphous. Photoluminescence measurements were conducted through 18 months and indicated that there is a very good intensive emission peaks near the violet regions. The FTIR measurements indicated the existence of peaks at 463, 604, 795 and a wide peak at 1111 cm{sup -1} and this can be attributed to Si-O-Si and Si-O stretching vibrations. We also report the formation of the octopus-like silicon oxide nanowires and the growth mechanism of these structures was discussed.

  1. High resolution spectroscopy in the microwave and far infrared

    Science.gov (United States)

    Pickett, Herbert M.

    1990-01-01

    High resolution rotational spectroscopy has long been central to remote sensing techniques in atmospheric sciences and astronomy. As such, laboratory measurements must supply the required data to make direct interpretation of data for instruments which sense atmospheres using rotational spectra. Spectral measurements in the microwave and far infrared regions are also very powerful tools when combined with infrared measurements for characterizing the rotational structure of vibrational spectra. In the past decade new techniques were developed which have pushed high resolution spectroscopy into the wavelength region between 25 micrometers and 2 mm. Techniques to be described include: (1) harmonic generation of microwave sources, (2) infrared laser difference frequency generation, (3) laser sideband generation, and (4) ultrahigh resolution interferometers.

  2. Science with High Spatial Resolution Far-Infrared Data

    Science.gov (United States)

    Terebey, Susan (Editor); Mazzarella, Joseph M. (Editor)

    1994-01-01

    The goal of this workshop was to discuss new science and techniques relevant to high spatial resolution processing of far-infrared data, with particular focus on high resolution processing of IRAS data. Users of the maximum correlation method, maximum entropy, and other resolution enhancement algorithms applicable to far-infrared data gathered at the Infrared Processing and Analysis Center (IPAC) for two days in June 1993 to compare techniques and discuss new results. During a special session on the third day, interested astronomers were introduced to IRAS HIRES processing, which is IPAC's implementation of the maximum correlation method to the IRAS data. Topics discussed during the workshop included: (1) image reconstruction; (2) random noise; (3) imagery; (4) interacting galaxies; (5) spiral galaxies; (6) galactic dust and elliptical galaxies; (7) star formation in Seyfert galaxies; (8) wavelet analysis; and (9) supernova remnants.

  3. High Resolution Lidar Digital Elevation Models and Low Resolution Shaded Relief Maps of Antarctica from USGS, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — Lidar high-resolution elevation digital elevation model data and low-resolution shaded relief maps of Antarctica are available for download from the U.S. Antarctic...

  4. A High Resolution Monolithic Crystal, DOI, MR Compatible, PET Detector

    Energy Technology Data Exchange (ETDEWEB)

    Robert S Miyaoka

    2012-03-06

    The principle objective of this proposal is to develop a positron emission tomography (PET) detector with depth-of-interaction (DOI) positioning capability that will achieve state of the art spatial resolution and sensitivity performance for small animal PET imaging. When arranged in a ring or box detector geometry, the proposed detector module will support <1 mm3 image resolution and >15% absolute detection efficiency. The detector will also be compatible with operation in a MR scanner to support simultaneous multi-modality imaging. The detector design will utilize a thick, monolithic crystal scintillator readout by a two-dimensional array of silicon photomultiplier (SiPM) devices using a novel sensor on the entrance surface (SES) design. Our hypothesis is that our single-ended readout SES design will provide an effective DOI positioning performance equivalent to more expensive dual-ended readout techniques and at a significantly lower cost. Our monolithic crystal design will also lead to a significantly lower cost system. It is our goal to design a detector with state of the art performance but at a price point that is affordable so the technology can be disseminated to many laboratories. A second hypothesis is that using SiPM arrays, the detector will be able to operate in a MR scanner without any degradation in performance to support simultaneous PET/MR imaging. Having a co-registered MR image will assist in radiotracer localization and may also be used for partial volume corrections to improve radiotracer uptake quantitation. The far reaching goal of this research is to develop technology for medical research that will lead to improvements in human health care.

  5. High resolution gas chromatography in dedicated petrochemical and environmental analysis

    International Nuclear Information System (INIS)

    Nijs, R. De

    1990-01-01

    Turn key systems dedicated and designed for a special application in petrochemical as well as environmental analysis are used already for many years. However, the use of high resolution gas chromatography columns in this type of equipment is only performed recently. In petrochemistry, examples of this type of systems are analyzers for light hydrocarbons, inerts and oxygenates in petrochemical streams and natural gas. In environmental monitoring analyzers for hydrocarbons and halogenated hydrocarbons in air or waste water and surface water are of importance. The use of capillary gas chromatography columns in this kind of application is resulting, when compared with packed columns, in improved separation power, a higher speed of analysis and in most cases a lower detection limit. Because of the high separation power of capillary columns, when compared with packed columns, the amount of columns needed to obtain a certain separation is less and so the analysis is simplified, becoming more reliable. For environmental analysis the use of high resolution columns in combination with thermal desorption could trap techniques in the analysis of volatile organic compound (VOC) in air results in information on ppb or even ppt level pollution of hydrocarbon and halogenated hydrocarbons. For the analysis of VOC's in water purge and trap techniques are used in combination with high resolution gas chromatography. Applications and results obtained with above mentioned equipment will be discussed. Special attention will be given to the incorporation of high resolution chromatography in this type of equipment

  6. High-resolution mask inspection in advanced fab

    Science.gov (United States)

    Maelzer, Stephanie; Poock, Andre; Reese, Bryan; Bhattacharyya, Kaustuve; Mirzaagha, Farzin; Cox, Stephen; Lang, Michael

    2006-10-01

    High resolution mask inspection in advanced wafer fabs is a necessity. Initial and progressive mask defect problem still remains an industry wide mask reliability issue. Defect incidences and its criticality vary significantly among the type of masks, technology node and layer, fab environment and mask usage. A usage and layer based qualification strategy for masks in production need to be adopted in wafer fabs. With the help of a high-resolution direct reticle inspection, early detection of critical and also non-critical defects at high capture rates is possible. A high-resolution inspection that is capable of providing necessary sensitivity to critical emerging defects (near edge) is very important in advanced nodes. At the same time, a way to disposition (make a go / no-go decision) on these defective masks is also very important. As the impact of these defects will depend on not only their size, but also on their transmission and MEEF, various defect types and characteristics have to be considered. In this technical report the adoption of such a high-resolution mask inspection system in wafer fab production is presented and discussed. Data on this work will include inspection results from advanced masks, layer and product based inspection pixel assignment, defect disposition and overall wafer fab strategies in day-to-day production towards mask inspection.

  7. Printable nanostructured silicon solar cells for high-performance, large-area flexible photovoltaics.

    Science.gov (United States)

    Lee, Sung-Min; Biswas, Roshni; Li, Weigu; Kang, Dongseok; Chan, Lesley; Yoon, Jongseung

    2014-10-28

    Nanostructured forms of crystalline silicon represent an attractive materials building block for photovoltaics due to their potential benefits to significantly reduce the consumption of active materials, relax the requirement of materials purity for high performance, and hence achieve greatly improved levelized cost of energy. Despite successful demonstrations for their concepts over the past decade, however, the practical application of nanostructured silicon solar cells for large-scale implementation has been hampered by many existing challenges associated with the consumption of the entire wafer or expensive source materials, difficulties to precisely control materials properties and doping characteristics, or restrictions on substrate materials and scalability. Here we present a highly integrable materials platform of nanostructured silicon solar cells that can overcome these limitations. Ultrathin silicon solar microcells integrated with engineered photonic nanostructures are fabricated directly from wafer-based source materials in configurations that can lower the materials cost and can be compatible with deterministic assembly procedures to allow programmable, large-scale distribution, unlimited choices of module substrates, as well as lightweight, mechanically compliant constructions. Systematic studies on optical and electrical properties, photovoltaic performance in experiments, as well as numerical modeling elucidate important design rules for nanoscale photon management with ultrathin, nanostructured silicon solar cells and their interconnected, mechanically flexible modules, where we demonstrate 12.4% solar-to-electric energy conversion efficiency for printed ultrathin (∼ 8 μm) nanostructured silicon solar cells when configured with near-optimal designs of rear-surface nanoposts, antireflection coating, and back-surface reflector.

  8. Generating High-Temporal and Spatial Resolution TIR Image Data

    Science.gov (United States)

    Herrero-Huerta, M.; Lagüela, S.; Alfieri, S. M.; Menenti, M.

    2017-09-01

    Remote sensing imagery to monitor global biophysical dynamics requires the availability of thermal infrared data at high temporal and spatial resolution because of the rapid development of crops during the growing season and the fragmentation of most agricultural landscapes. Conversely, no single sensor meets these combined requirements. Data fusion approaches offer an alternative to exploit observations from multiple sensors, providing data sets with better properties. A novel spatio-temporal data fusion model based on constrained algorithms denoted as multisensor multiresolution technique (MMT) was developed and applied to generate TIR synthetic image data at both temporal and spatial high resolution. Firstly, an adaptive radiance model is applied based on spectral unmixing analysis of . TIR radiance data at TOA (top of atmosphere) collected by MODIS daily 1-km and Landsat - TIRS 16-day sampled at 30-m resolution are used to generate synthetic daily radiance images at TOA at 30-m spatial resolution. The next step consists of unmixing the 30 m (now lower resolution) images using the information about their pixel land-cover composition from co-registered images at higher spatial resolution. In our case study, TIR synthesized data were unmixed to the Sentinel 2 MSI with 10 m resolution. The constrained unmixing preserves all the available radiometric information of the 30 m images and involves the optimization of the number of land-cover classes and the size of the moving window for spatial unmixing. Results are still being evaluated, with particular attention for the quality of the data streams required to apply our approach.

  9. GENERATING HIGH-TEMPORAL AND SPATIAL RESOLUTION TIR IMAGE DATA

    Directory of Open Access Journals (Sweden)

    M. Herrero-Huerta

    2017-09-01

    Full Text Available Remote sensing imagery to monitor global biophysical dynamics requires the availability of thermal infrared data at high temporal and spatial resolution because of the rapid development of crops during the growing season and the fragmentation of most agricultural landscapes. Conversely, no single sensor meets these combined requirements. Data fusion approaches offer an alternative to exploit observations from multiple sensors, providing data sets with better properties. A novel spatio-temporal data fusion model based on constrained algorithms denoted as multisensor multiresolution technique (MMT was developed and applied to generate TIR synthetic image data at both temporal and spatial high resolution. Firstly, an adaptive radiance model is applied based on spectral unmixing analysis of . TIR radiance data at TOA (top of atmosphere collected by MODIS daily 1-km and Landsat – TIRS 16-day sampled at 30-m resolution are used to generate synthetic daily radiance images at TOA at 30-m spatial resolution. The next step consists of unmixing the 30 m (now lower resolution images using the information about their pixel land-cover composition from co-registered images at higher spatial resolution. In our case study, TIR synthesized data were unmixed to the Sentinel 2 MSI with 10 m resolution. The constrained unmixing preserves all the available radiometric information of the 30 m images and involves the optimization of the number of land-cover classes and the size of the moving window for spatial unmixing. Results are still being evaluated, with particular attention for the quality of the data streams required to apply our approach.

  10. Constraining Stochastic Parametrisation Schemes Using High-Resolution Model Simulations

    Science.gov (United States)

    Christensen, H. M.; Dawson, A.; Palmer, T.

    2017-12-01

    Stochastic parametrisations are used in weather and climate models as a physically motivated way to represent model error due to unresolved processes. Designing new stochastic schemes has been the target of much innovative research over the last decade. While a focus has been on developing physically motivated approaches, many successful stochastic parametrisation schemes are very simple, such as the European Centre for Medium-Range Weather Forecasts (ECMWF) multiplicative scheme `Stochastically Perturbed Parametrisation Tendencies' (SPPT). The SPPT scheme improves the skill of probabilistic weather and seasonal forecasts, and so is widely used. However, little work has focused on assessing the physical basis of the SPPT scheme. We address this matter by using high-resolution model simulations to explicitly measure the `error' in the parametrised tendency that SPPT seeks to represent. The high resolution simulations are first coarse-grained to the desired forecast model resolution before they are used to produce initial conditions and forcing data needed to drive the ECMWF Single Column Model (SCM). By comparing SCM forecast tendencies with the evolution of the high resolution model, we can measure the `error' in the forecast tendencies. In this way, we provide justification for the multiplicative nature of SPPT, and for the temporal and spatial scales of the stochastic perturbations. However, we also identify issues with the SPPT scheme. It is therefore hoped these measurements will improve both holistic and process based approaches to stochastic parametrisation. Figure caption: Instantaneous snapshot of the optimal SPPT stochastic perturbation, derived by comparing high-resolution simulations with a low resolution forecast model.

  11. High resolution multiplexed functional imaging in live embryos (Conference Presentation)

    Science.gov (United States)

    Xu, Dongli; Zhou, Weibin; Peng, Leilei

    2017-02-01

    Fourier multiplexed fluorescence lifetime imaging (FmFLIM) scanning laser optical tomography (FmFLIM-SLOT) combines FmFLIM and Scanning laser optical tomography (SLOT) to perform multiplexed 3D FLIM imaging of live embryos. The system had demonstrate multiplexed functional imaging of zebrafish embryos genetically express Foster Resonant Energy Transfer (FRET) sensors. However, previous system has a 20 micron resolution because the focused Gaussian beam diverges quickly from the focused plane, makes it difficult to achieve high resolution imaging over a long projection depth. Here, we present a high-resolution FmFLIM-SLOT system with achromatic Bessel beam, which achieves 3 micron resolution in 3D deep tissue imaging. In Bessel-FmFLIM-SLOT, multiple laser excitation lines are firstly intensity modulated by a Michelson interferometer with a spinning polygon mirror optical delay line, which enables Fourier multiplexed multi-channel lifetime measurements. Then, a spatial light modulator and a prism are used to transform the modulated Gaussian laser beam to an achromatic Bessel beam. The achromatic Bessel beam scans across the whole specimen with equal angular intervals as sample rotated. After tomography reconstruction and the frequency domain lifetime analysis method, both the 3D intensity and lifetime image of multiple excitation-emission can be obtained. Using Bessel-FmFLIM-SLOT system, we performed cellular-resolution FLIM tomography imaging of live zebrafish embryo. Genetically expressed FRET sensors in these embryo will allow non-invasive observation of multiple biochemical processes in vivo.

  12. High resolution muon computed tomography at neutrino beam facilities

    International Nuclear Information System (INIS)

    Suerfu, B.; Tully, C.G.

    2016-01-01

    X-ray computed tomography (CT) has an indispensable role in constructing 3D images of objects made from light materials. However, limited by absorption coefficients, X-rays cannot deeply penetrate materials such as copper and lead. Here we show via simulation that muon beams can provide high resolution tomographic images of dense objects and of structures within the interior of dense objects. The effects of resolution broadening from multiple scattering diminish with increasing muon momentum. As the momentum of the muon increases, the contrast of the image goes down and therefore requires higher resolution in the muon spectrometer to resolve the image. The variance of the measured muon momentum reaches a minimum and then increases with increasing muon momentum. The impact of the increase in variance is to require a higher integrated muon flux to reduce fluctuations. The flux requirements and level of contrast needed for high resolution muon computed tomography are well matched to the muons produced in the pion decay pipe at a neutrino beam facility and what can be achieved for momentum resolution in a muon spectrometer. Such an imaging system can be applied in archaeology, art history, engineering, material identification and whenever there is a need to image inside a transportable object constructed of dense materials

  13. Resolution-recovery-embedded image reconstruction for a high-resolution animal SPECT system.

    Science.gov (United States)

    Zeraatkar, Navid; Sajedi, Salar; Farahani, Mohammad Hossein; Arabi, Hossein; Sarkar, Saeed; Ghafarian, Pardis; Rahmim, Arman; Ay, Mohammad Reza

    2014-11-01

    The small-animal High-Resolution SPECT (HiReSPECT) is a dedicated dual-head gamma camera recently designed and developed in our laboratory for imaging of murine models. Each detector is composed of an array of 1.2 × 1.2 mm(2) (pitch) pixelated CsI(Na) crystals. Two position-sensitive photomultiplier tubes (H8500) are coupled to each head's crystal. In this paper, we report on a resolution-recovery-embedded image reconstruction code applicable to the system and present the experimental results achieved using different phantoms and mouse scans. Collimator-detector response functions (CDRFs) were measured via a pixel-driven method using capillary sources at finite distances from the head within the field of view (FOV). CDRFs were then fitted by independent Gaussian functions. Thereafter, linear interpolations were applied to the standard deviation (σ) values of the fitted Gaussians, yielding a continuous map of CDRF at varying distances from the head. A rotation-based maximum-likelihood expectation maximization (MLEM) method was used for reconstruction. A fast rotation algorithm was developed to rotate the image matrix according to the desired angle by means of pre-generated rotation maps. The experiments demonstrated improved resolution utilizing our resolution-recovery-embedded image reconstruction. While the full-width at half-maximum (FWHM) radial and tangential resolution measurements of the system were over 2 mm in nearly all positions within the FOV without resolution recovery, reaching around 2.5 mm in some locations, they fell below 1.8 mm everywhere within the FOV using the resolution-recovery algorithm. The noise performance of the system was also acceptable; the standard deviation of the average counts per voxel in the reconstructed images was 6.6% and 8.3% without and with resolution recovery, respectively. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  14. Photonic integration and photonics-electronics convergence on silicon platform

    CERN Document Server

    Liu, Jifeng; Baba, Toshihiko; Vivien, Laurent; Xu, Dan-Xia

    2015-01-01

    Silicon photonics technology, which has the DNA of silicon electronics technology, promises to provide a compact photonic integration platform with high integration density, mass-producibility, and excellent cost performance. This technology has been used to develop and to integrate various photonic functions on silicon substrate. Moreover, photonics-electronics convergence based on silicon substrate is now being pursued. Thanks to these features, silicon photonics will have the potential to be a superior technology used in the construction of energy-efficient cost-effective apparatuses for various applications, such as communications, information processing, and sensing. Considering the material characteristics of silicon and difficulties in microfabrication technology, however, silicon by itself is not necessarily an ideal material. For example, silicon is not suitable for light emitting devices because it is an indirect transition material. The resolution and dynamic range of silicon-based interference de...

  15. High-dimensional quantum key distribution based on multicore fiber using silicon photonic integrated circuits

    DEFF Research Database (Denmark)

    Ding, Yunhong; Bacco, Davide; Dalgaard, Kjeld

    2017-01-01

    is intrinsically limited to 1 bit/photon. Here we propose and experimentally demonstrate, for the first time, a high-dimensional quantum key distribution protocol based on space division multiplexing in multicore fiber using silicon photonic integrated lightwave circuits. We successfully realized three mutually......-dimensional quantum states, and enables breaking the information efficiency limit of traditional quantum key distribution protocols. In addition, the silicon photonic circuits used in our work integrate variable optical attenuators, highly efficient multicore fiber couplers, and Mach-Zehnder interferometers, enabling...... manipulating high-dimensional quantum states in a compact and stable manner. Our demonstration paves the way to utilize state-of-the-art multicore fibers for noise tolerance high-dimensional quantum key distribution, and boost silicon photonics for high information efficiency quantum communications....

  16. A Highly Responsive Silicon Nanowire/Amplifier MOSFET Hybrid Biosensor

    Science.gov (United States)

    2015-07-21

    Hybrid Biosensor Jieun Lee1,2, Jaeman Jang1, Bongsik Choi1, Jinsu Yoon1, Jee-Yeon Kim3, Yang-Kyu Choi3, Dong Myong Kim1, Dae Hwan Kim1 & Sung-Jin Choi1...This study demonstrates a hybrid biosensor comprised of a silicon nanowire (SiNW) integrated with an amplifier MOSFET to improve the current response...of field-effect-transistor (FET)-based biosensors . The hybrid biosensor is fabricated using conventional CMOS technology, which has the potential

  17. Transport properties of microcrystalline silicon prepared at high growth rate

    Czech Academy of Sciences Publication Activity Database

    Kočka, Jan; Mates, Tomáš; Ledinský, Martin; Stuchlíková, The-Ha; Stuchlík, Jiří; Fejfar, Antonín

    2006-01-01

    Roč. 352, - (2006), s. 1092-1100 ISSN 0022-3093 R&D Projects: GA MŠk(CZ) LC510; GA MŽP(CZ) SM/300/1/03; GA AV ČR(CZ) IAA1010316; GA AV ČR(CZ) IAA1010413; GA ČR(CZ) GD202/05/H003 Institutional research plan: CEZ:AV0Z10100521 Keywords : amorphous semiconductors * silicon * crystal growth * nanocrystals * electrical and electronic properties * conductivity * atomic force and scanning tunneling microscopy * microcrystallinity * photoconductivity * Raman spectroscopy Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.362, year: 2006

  18. Isothermal treatment of SAE92XX type high silicon steels

    International Nuclear Information System (INIS)

    Paez, J.L.; Fuentes, F.; Battegliese, A.

    1996-01-01

    SAE 9260 type steels have silicon and carbon contents similar to thoseof the ductile iron matrix, and present a bainitic transformation with the same characteristics as ADI (Austempered Ductile Iron). The hypothesis is that excellent mechanical properties can be obtained by means of austempering (in times so short as to be accessible from the industrial point of view), the same as in ADI and even better because it is a rolling material instead of a cast materials. It will be compared with the mechanical properties obtained by quenching and tempering at different temperatures. (Author) 8 refs

  19. High-Resolution Electronics: Spontaneous Patterning of High-Resolution Electronics via Parallel Vacuum Ultraviolet (Adv. Mater. 31/2016).

    Science.gov (United States)

    Liu, Xuying; Kanehara, Masayuki; Liu, Chuan; Sakamoto, Kenji; Yasuda, Takeshi; Takeya, Jun; Minari, Takeo

    2016-08-01

    On page 6568, T. Minari and co-workers describe spontaneous patterning based on the parallel vacuum ultraviolet (PVUV) technique, enabling the homogeneous integration of complex, high-resolution electronic circuits, even on large-scale, flexible, transparent substrates. Irradiation of PVUV to the hydrophobic polymer surface precisely renders the selected surface into highly wettable regions with sharply defined boundaries, which spontaneously guides a metal nanoparticle ink into a series of circuit lines and gaps with the widths down to a resolution of 1 μm. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. The charge collection in silicon strip detectors

    International Nuclear Information System (INIS)

    Boehringer, T.; Hubbeling, L.; Weilhammer, P.; Kemmer, J.; Koetz, U.; Riebesell, M.; Belau, E.; Klanner, R.; Lutz, G.; Neugebauer, E.; Seebrunner, H.J.; Wylie, A.

    1983-02-01

    The charge collection in silicon detectors has been studied, by measuring the response to high-energy particles of a 20μm pitch strip detector as a function of applied voltage and magnetic field. The results are well described by a simple model. The model is used to predict the spatial resolution of silicon strip detectors and to propose a detector with optimized spatial resolution. (orig.)

  1. Duchenne muscular dystrophy: High-resolution melting curve ...

    African Journals Online (AJOL)

    Duchenne muscular dystrophy: High-resolution melting curve analysis as an affordable diagnostic mutation scanning tool in a South African cohort. ... Genetic screening for D/BMD in South Africa currently includes multiple ligase-dependent probe amplification (MLPA) for exonic deletions and duplications and linkage ...

  2. Interpretation of high resolution aeromagnetic data over southern ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 125; Issue 2 ... High resolution airborne magnetic data of parts of the southern Benue Trough were digitally processed and analyzed in order to estimate the depth of magnetic sources and to map the distribution and orientation of subsurface structural features.

  3. High Resolution Mass Spectrometry of Polyfluorinated Polyether - based Formulation

    NARCIS (Netherlands)

    Dimzon, I.K.; Trier, X; Frömel, T.; Helmus, R.; Knepper, T.P.; de Voogt, P.

    High resolution mass spectrometry (HRMS) was successfully applied to elucidate the structure of a polyfluorinated polyether (PFPE)-based formulation. The mass spectrum generated from direct injection into the MS was examined by identifying the different repeating units manually and with the aid of

  4. Dye laser light for high-resolution classical photography

    International Nuclear Information System (INIS)

    Geissler, K.K.

    1982-01-01

    The test run with the bubble chamber HOLEBC in October 1981 offered the opportunity of checking the usefulness of de-speckled dye laser light for illumination purposes in high-resolution classical dark field photography of small bubble chambers. (orig./HSI)

  5. High-resolution palaeoclimatology of the last millennium

    DEFF Research Database (Denmark)

    Vinther, Bo Møllesøe; Jones, P.D.; Briffa, K.R.

    2009-01-01

    Palaeoclimatology • high-resolution • last millennium • tree rings • dendroclimatology • chronology • uncertainty • corals • ice-cores • speleothems • documentary evidence • instrumental records • varves • borehole temperature • marine sediments • composite plus scaling • CPS • climate field...

  6. High resolution X-ray diffraction studies on unirradiated

    Indian Academy of Sciences (India)

    High-resolution X-ray diffraction technique, employing a three-crystal monochromator–collimator combination is used to study the irradiation induced defects in flux grown Sr-hexaferrite crystals irradiated with 50 MeV Li3+ ion beams at room temperature with a fluence value of 1 × 1014 ions/cm2. The diffraction curves of the ...

  7. Structure Identification in High-Resolution Transmission Electron Microscopic Images

    DEFF Research Database (Denmark)

    Vestergaard, Jacob Schack; Kling, Jens; Dahl, Anders Bjorholm

    2014-01-01

    A connection between microscopic structure and macroscopic properties is expected for almost all material systems. High-resolution transmission electron microscopy is a technique offering insight into the atomic structure, but the analysis of large image series can be time consuming. The present ...

  8. Systematic high-resolution assessment of global hydropower potential

    NARCIS (Netherlands)

    Hoes, Olivier A C; Meijer, Lourens J J; Van Der Ent, Ruud J.; Van De Giesen, Nick C.

    2017-01-01

    Population growth, increasing energy demand and the depletion of fossil fuel reserves necessitate a search for sustainable alternatives for electricity generation. Hydropower could replace a large part of the contribution of gas and oil to the present energy mix. However, previous high-resolution

  9. Application of high resolution SNP arrays in patients with congenital ...

    Indian Academy of Sciences (India)

    c Indian Academy of Sciences. RESEARCH ARTICLE. Application of high resolution SNP arrays in patients with congenital oral clefts in south .... developmental delays, autism and multiple congenital anom- alies. In these studies, the diagnostic yield was much higher than that of standard GTG-banded karyotyping (de Vries.

  10. High resolution STEM of quantum dots and quantum wires

    DEFF Research Database (Denmark)

    Kadkhodazadeh, Shima

    2013-01-01

    This article reviews the application of high resolution scanning transmission electron microscopy (STEM) to semiconductor quantum dots (QDs) and quantum wires (QWRs). Different imaging and analytical techniques in STEM are introduced and key examples of their application to QDs and QWRs...

  11. On high-resolution manoeuvres control via trajectory optimization

    Indian Academy of Sciences (India)

    This research is on a realization of control approach in line with the trajectory optimization for the purpose of dealing with overactuated spacecraft in the process of the high-resolution manoeuvres. The idea behind the research is to realize closed control loops to cope with the rotational angles and the corresponding angular ...

  12. High resolution numerical weather prediction over the Indian ...

    Indian Academy of Sciences (India)

    In this study, the Florida State University Global Spectral Model (FSUGSM), in association with a high-resolution nested regional spectral model (FSUNRSM), is used for short-range weather forecasts over the Indian domain. Three-day forecasts for each day of August 1998 were performed using different versions of the ...

  13. HIGH RESOLUTION RESISTIVITY LEAK DETECTION DATA PROCESSING & EVALUATION MEHTODS & REQUIREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    SCHOFIELD JS

    2007-10-04

    This document has two purposes: {sm_bullet} Describe how data generated by High Resolution REsistivity (HRR) leak detection (LD) systems deployed during single-shell tank (SST) waste retrieval operations are processed and evaluated. {sm_bullet} Provide the basic review requirements for HRR data when Hrr is deployed as a leak detection method during SST waste retrievals.

  14. High Resolution Stellar Spectroscopy with VBT Echelle Spectrometer

    Indian Academy of Sciences (India)

    High Resolution Stellar Spectroscopy with VBT Echelle Spectrometer. N. Kameswara Rao, S. Sriram, K. Jayakumar & F. Gabriel. Indian Institute of Astrophysics, Bangalore 560 034, India. Abstract. The optical design and performance of the recently commis- sioned fiber fed echelle spectrometer of 2.34 meter Vainu Bappu ...

  15. High resolution reflection seismic mapping of shallow coal seams

    CSIR Research Space (South Africa)

    Mngadi, SB

    2013-10-01

    Full Text Available Subsidence and collapse of unmapped shallow coal mine workings poses a risk to the public and hampers the development of valuable property. A high-resolution reflection seismic survey was conducted to determine whether it is possible to map...

  16. Tamarisk Mapping and Monitoring Using High Resolution Satellite Imagery

    Science.gov (United States)

    Jason W. San Souci; John T. Doyle

    2006-01-01

    QuickBird high resolution multispectral satellite imagery (60 cm GSD, 4 spectral bands) and calibrated products from DigitalGlobe’s AgroWatch program were used as inputs to Visual Learning System’s Feature Analyst automated feature extraction software to map localized occurrences of pervasive and aggressive Tamarisk (Tamarix ramosissima), an invasive...

  17. High Resolution Stellar Spectroscopy with VBT Echelle Spectrometer

    Indian Academy of Sciences (India)

    Introduction. An efficient high resolution spectrometer has been a long standing need at Vainu Bappu. Observatory (that could cover a large region of the spectrum extending from 4000 Å to. 1 µm in one exposure) for stellar spectroscopic programmes. The obvious choice that emerged is an echelle grating based ...

  18. High resolution PIXE using different orders of reflection

    Science.gov (United States)

    Török, I.

    1992-05-01

    A Soller-type X-ray crystal spectrometer on an ion beam of the ATOMKI 5 MV Van de Graaff generator was used to perform high resolution PIXE measurements. The measurement of the dolomitization grade of natural limestones served as a case study for several methods on how to optimize such an analysis.

  19. Pattern of interstitial lung disease detected by high resolution ...

    African Journals Online (AJOL)

    High Resolution Computed Tomography (HRCT) is the recommended imaging technique in the diagnosis, assessment and followup of these diseases. Objectives: To describe the pattern of HRCT ... This is important in narrowing the differential diagnosis as well as for pre-biopsy planning. The diagnosis of ILD requires a ...

  20. Data Evaluation Procedure for High-resolution Neutron Diffraction Methods

    Czech Academy of Sciences Publication Activity Database

    Strunz, Pavel; Lukáš, Petr; Neov, Dimitar

    2001-01-01

    Roč. 9, - (2001), s. 99-106 ISSN 1023-8166 R&D Projects: GA ČR GV202/97/K038 Institutional research plan: CEZ:AV0Z1048901 Keywords : high-resolution neutron diffraction * profile analysis * modeling Subject RIV: BM - Solid Matter Physics ; Magnetism

  1. High resolution wind turbine wake measurements with a scanning lidar

    DEFF Research Database (Denmark)

    Herges, T. G.; Maniaci, D. C.; Naughton, B. T.

    2017-01-01

    High-resolution lidar wake measurements are part of an ongoing field campaign being conducted at the Scaled Wind Farm Technology facility by Sandia National Laboratories and the National Renewable Energy Laboratory using a customized scanning lidar from the Technical University of Denmark. One...

  2. Generating high-temporal and spatial resolution tir image data

    NARCIS (Netherlands)

    Herrero Huerta, M.; Lagüela, S.; Alfieri, S.M.; Menenti, M.; Lichti, D.; Weng, Q

    2017-01-01

    Remote sensing imagery to monitor global biophysical dynamics requires the availability of thermal infrared data at high temporal and spatial resolution because of the rapid development of crops during the growing season and the fragmentation of most agricultural landscapes. Conversely, no single

  3. Gemini high-resolution optical spectrograph conceptual design

    Science.gov (United States)

    Szeto, Kei; McConnachie, Alan; Anthony, André; Bohlender, David; Crampton, David; Desaulniers, Pierre; Dunn, Jennifer; Hardy, Tim; Hill, Alexis; Monin, Dmitry; Pazder, John; Schwab, Christian; Spano, Paola; Starkenburg, Else; Thibault, Simon; Walker, Gordon; Venn, Kim; Zhang, Hu

    2012-09-01

    A multiplexed moderate resolution (R = 34,000) and a single object high resolution (R = 90,000) spectroscopic facility for the entire 340 - 950nm wavelength region has been designed for Gemini. The result is a high throughput, versatile instrument that will enable precision spectroscopy for decades to come. The extended wavelength coverage for these relatively high spectral resolutions is achieved by use of an Echelle grating with VPH cross-dispersers and for the R = 90,000 mode utilization of an image slicer. The design incorporates a fast, efficient, reliable system for acquiring targets over the7 arcmin field of Gemini. This paper outlines the science case development and requirements flow-down process that leads to the configuration of the HIA instrument and describes the overall GHOS conceptual design. In addition, this paper discusses design trades examined during the conceptual design study instrument group of the Herzberg Institute of Astrophysics has been commissioned by the Gemini Observatory as one of the three competing organizations to conduct a conceptual design study for a new Gemini High-Resolution Optical Spectrograph (GHOS). This paper outlines the science case development and requirements flow-down process that leads to the configuration of the HIA instrument and describes the overall GHOS conceptual design. In addition, this paper discusses design trades examined during the conceptual design study.

  4. Track prediction of very severe cyclone 'Nargis' using high resolution ...

    Indian Academy of Sciences (India)

    In the present study, a detailed diagnostic analysis of the system 'Nargis' is carried out initially to investigate the features associated with this unusual movement and subsequently the real time forecast of VSCS 'Nargis' using high resolution advanced version weather research forecasting (WRF) model is presented.

  5. High resolution numerical weather prediction over the Indian ...

    Indian Academy of Sciences (India)

    with the high resolution physical initialization within the FSUNRSM along with explicit speci- fication of soil temperatures. Section 5 describes the data, experimental setup and results obtained using the multimodel/multianalysis superensem- ble method, and a detailed summary, conclu- sions and scope for future work are ...

  6. On high-resolution manoeuvres control via trajectory optimization

    Indian Academy of Sciences (India)

    The outcomes are realized through the variations of the orbital parameters, including the inclination, the eccentricity, the angular momentum, the semi-major axis and so on, in the high-resolution manoeuvres. It aims to get the system under control to guarantee the performance of the three-dimensional rotational angles ...

  7. RESEARCH ARTICLE Application of high resolution SNP arrays in ...

    Indian Academy of Sciences (India)

    User

    and/or palate phenotypes. Tan et al. (2013) identified a de novo 2.3 Mb microdeletion of 1q32.2 involving the Van der Woude Syndrome locus using a high resolution single nucleotide poly-morphism (SNP) array. In our study, we used the CytoScanTM HD array platform provided by the Affymetrix Corporation to analyze 33 ...

  8. Remote parallel rendering for high-resolution tiled display walls

    KAUST Repository

    Nachbaur, Daniel

    2014-11-01

    © 2014 IEEE. We present a complete, robust and simple to use hardware and software stack delivering remote parallel rendering of complex geometrical and volumetric models to high resolution tiled display walls in a production environment. We describe the setup and configuration, present preliminary benchmarks showing interactive framerates, and describe our contributions for a seamless integration of all the software components.

  9. High energy resolution off-resonant X-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wojciech, Blachucki [Univ. of Fribourg (Switzerland). Dept. of Physics

    2015-10-16

    This work treats of the high energy resolution off-resonant X-ray spectroscopy (HEROS) method of determining the density of unoccupied electronic states in the vicinity of the absorption edge. HEROS is an alternative to the existing X-ray absorption spectroscopy (XAS) methods and opens the way for new studies not achievable before.

  10. Interpretation of high resolution aeromagnetic data over southern ...

    Indian Academy of Sciences (India)

    and Hilbert transform of magnetic data reported the existence of two main ... digital high resolution data over the existing data in which most of the .... Transform (FFT). The enhancement routines per- formed in this work include, reduction to pole (RTP), reduction to equator (RTE), first and second ver- tical derivatives (1VD ...

  11. Human enamel structure studied by high resolution electron microscopy

    International Nuclear Information System (INIS)

    Wen, S.L.

    1989-01-01

    Human enamel structural features are characterized by high resolution electron microscopy. The human enamel consists of polycrystals with a structure similar to Ca10(PO4)6(OH)2. This article describes the structural features of human enamel crystal at atomic and nanometer level. Besides the structural description, a great number of high resolution images are included. Research into the carious process in human enamel is very important for human beings. This article firstly describes the initiation of caries in enamel crystal at atomic and unit-cell level and secondly describes the further steps of caries with structural and chemical demineralization. The demineralization in fact, is the origin of caries in human enamel. The remineralization of carious areas in human enamel has drawn more and more attention as its potential application is realized. This process has been revealed by high resolution electron microscopy in detail in this article. On the other hand, the radiation effects on the structure of human enamel are also characterized by high resolution electron microscopy. In order to reveal this phenomenon clearly, a great number of electron micrographs have been shown, and a physical mechanism is proposed. 26 references

  12. High-resolution seismic imaging of the Sohagpur Gondwana basin ...

    Indian Academy of Sciences (India)

    through a high-resolution seismic reflection study along six profiles, covering the central part of the. Sohagpur basin. The study reveals (1) ~1000 m thick, gently dipping Barakar Formation, (2) thick coal seams at a depth of 350–550 m, and (3) NNW–SSE to NW–SE striking steeply dipping normal faults defining rift geometry.

  13. Workshop on high-resolution, large-acceptance spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Zeidman, B. (ed.)

    1981-01-01

    The purpose of the Workshop on High-Resolution, Large-Acceptance Spectrometers was to provide a means for exchange of information among those actively engaged in the design and construction of these new spectrometers. Thirty-seven papers were prepared for the data base.

  14. Raman Spectra of High-κ Dielectric Layers Investigated with Micro-Raman Spectroscopy Comparison with Silicon Dioxide

    Directory of Open Access Journals (Sweden)

    P. Borowicz

    2013-01-01

    Full Text Available Three samples with dielectric layers from high-κ dielectrics, hafnium oxide, gadolinium-silicon oxide, and lanthanum-lutetium oxide on silicon substrate were studied by Raman spectroscopy. The results obtained for high-κ dielectrics were compared with spectra recorded for silicon dioxide. Raman spectra suggest the similarity of gadolinium-silicon oxide and lanthanum-lutetium oxide to the bulk nondensified silicon dioxide. The temperature treatment of hafnium oxide shows the evolution of the structure of this material. Raman spectra recorded for as-deposited hafnium oxide are similar to the results obtained for silicon dioxide layer. After thermal treatment especially at higher temperatures (600°C and above, the structure of hafnium oxide becomes similar to the bulk non-densified silicon dioxide.

  15. The development of p-type silicon detectors for the high radiation regions of the LHC

    CERN Document Server

    Hanlon, M D L

    1998-01-01

    This thesis describes the production and characterisation of silicon microstrip detectors and test structures on p-type substrates. An account is given of the production and full parameterisation of a p-type microstrip detector, incorporating the ATLAS-A geometry in a beam test. This detector is an AC coupled device incorporating a continuous p-stop isolation frame and polysilicon biasing and is typical of n-strip devices proposed for operation at the LHC. It was successfully read out using the FELix-128 analogue pipeline chip and a signal to noise (s/n) of 17+-1 is reported, along with a spatial resolution of 14.6+-0.2 mu m. Diode test structures were fabricated on both high resistivity float zone material and on epitaxial material and subsequently irradiated with 24 GeV protons at the CERN PS up to a dose of (8.22+-0.23) x 10 sup 1 sup 4 per cm sup 2. An account of the measurement program is presented along with results on the changes in the effective doping concentration (N sub e sub f sub f) with irradiat...

  16. Metallurgy of high-silicon steel parts produced using Selective Laser Melting

    International Nuclear Information System (INIS)

    Garibaldi, Michele; Ashcroft, Ian; Simonelli, Marco; Hague, Richard

    2016-01-01

    The metallurgy of high-silicon steel (6.9%wt.Si) processed using Selective Laser Melting (SLM) is presented for the first time in this study. High-silicon steel has great potential as a soft magnetic alloy, but its employment has been limited due to its poor workability. The effect of SLM-processing on the metallurgy of the alloy is investigated in this work using microscopy, X-Ray Diffraction (XRD) and Electron Backscatter Diffraction (EBSD). XRD analysis suggests that the SLM high-silicon steel is a single ferritic phase (solid solution), with no sign of phase ordering. This is expected to have beneficial effects on the material properties, since ordering has been shown to make silicon steels more brittle and electrically conductive. For near-fully dense samples, columnar grains with a high aspect ratio and oriented along the build direction are found. Most importantly, a <001> fibre-texture along the build direction can be changed into a cube-texture when the qualitative shape of the melt-pool is altered (from shallow to deep) by increasing the energy input of the scanning laser. This feature could potentially open the path to the manufacture of three-dimensional grain-oriented high-silicon steels for electromechanical applications.

  17. Development of manufacturing capability for high-concentration, high-efficiency silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sinton, R.A.; Verlinden, P.J.; Crane, R.A.; Swanson, R.N. [SunPower Corp., Sunnyvale, CA (United States)

    1996-10-01

    This report presents a summary of the major results from a program to develop a manufacturable, high-efficiency silicon concentrator solar cell and a cost-effective manufacturing facility. The program was jointly funded by the Electric Power Research Institute, Sandia National Laboratories through the Concentrator Initiative, and SunPower Corporation. The key achievements of the program include the demonstration of 26%-efficient silicon concentrator solar cells with design-point (20 W/cm{sup 2}) efficiencies over 25%. High-performance front-surface passivations; that were developed to achieve this result were verified to be absolutely stable against degradation by 475 days of field exposure at twice the design concentration. SunPower demonstrated pilot production of more than 1500 of these cells. This cell technology was also applied to pilot production to supply 7000 17.7-cm{sup 2} one-sun cells (3500 yielded wafers) that demonstrated exceptional quality control. The average efficiency of 21.3% for these cells approaches the peak efficiency ever demonstrated for a single small laboratory cell within 2% (absolute). Extensive cost models were developed through this program and calibrated by the pilot-production project. The production levels achieved indicate that SunPower could produce 7-10 MW of concentrator cells per year in the current facility based upon the cell performance demonstrated during the program.

  18. Solutions on high-resolution multiple configuration system sensors

    Science.gov (United States)

    Liu, Hua; Ding, Quanxin; Guo, Chunjie; Zhou, Liwei

    2014-11-01

    For aim to achieve an improved resolution in modern image domain, a method of continuous zoom multiple configuration, with a core optics is attempt to establish model by novel principle on energy transfer and high accuracy localization, by which the system resolution can be improved with a level in nano meters. A comparative study on traditional vs modern methods can demonstrate that the dialectical relationship and their balance is important, among Merit function, Optimization algorithms and Model parameterization. The effect of system evaluated criterion that MTF, REA, RMS etc. can support our arguments qualitatively.

  19. Topography improvements in MEMS DMs for high-contrast, high-resolution imaging, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will develop and demonstrate an innovative microfabrication process to substantially improve the surface quality achievable in high-resolution...

  20. Topography improvements in MEMS DMs for high-contrast, high-resolution imaging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will develop and demonstrate an innovative microfabrication process to substantially improve the surface quality achievable in high-resolution...