Science.gov

Sample records for 320x240 pixel lec

  1. X-ray imaging using a 320 x 240 hybrid GaAs pixel detector

    SciTech Connect

    Irsigler, R.; Andersson, J.; Alverbro, J.

    1999-06-01

    The authors present room temperature measurements on 200 {micro}m thick GaAs pixel detectors, which were hybridized to silicon readout circuits. The whole detector array contains 320 x 240 square shaped pixel with a pitch of 38 {micro}m and is based on semi-insulating liquid-encapsulated Czochralski (LEC) GaAs material. After fabricating and dicing, the detector chips were indium bump flip chip bonded to CMOS readout circuits based on charge integration and finally evaluated. This readout chip was originally designed for the readout of flip chip bonded infrared detectors, but appears to be suitable for X-ray applications as well. A bias voltage between 50 V and 100 V was sufficient to operate the detector at room temperature. The detector array did respond to x-ray radiation by an increase in current due to production of electron hole pairs by the ionization processes. Images of various objects and slit patterns were acquired by using a standard X-ray source for dental imaging. The new X-ray hybrid detector was analyzed with respect to its imaging properties. Due to the high absorption coefficient for X-rays in GaAs and the small pixel size, the sensor shows a high modulation transfer function up to the Nyquist frequency.

  2. 320 x 240 uncooled IRFPA with pixel wise thin film vacuum packaging

    NASA Astrophysics Data System (ADS)

    Yon, J.-J.; Dumont, G.; Rabaud, W.; Becker, S.; Carle, L.; Goudon, V.; Vialle, C.; Hamelin, A.; Arnaud, A.

    2012-10-01

    Silicon based vacuum packaging is a key enabling technology for achieving affordable uncooled Infrared Focal Plane Arrays (IRFPA) as required by the promising mass market for very low cost IR applications, such as automotive driving assistance, energy loss monitoring in buildings, motion sensors… Among the various approaches studied worldwide, the CEA, LETI is developing a unique technology where each bolometer pixel is sealed under vacuum at the wafer level, using an IR transparent thin film deposition. This technology referred to as PLP (Pixel Level Packaging), leads to an array of hermetic micro-caps each containing a single microbolometer. Since the successful demonstration that the PLP technology, when applied on a single microbolometer pixel, can provide the required vacuum < 10-3 mbar, the authors have pushed forward the development of the technology on fully operational QVGA readout circuits CMOS base wafers (320 x 240 pixels). In this outlook, the article reports on the electro optical performance obtained from this preliminary PLP based QVGA demonstrator. Apart from the response, noise and NETD distributions, the paper also puts emphasis on additional key features such as thermal time constant, image quality, and ageing properties.

  3. High-performance and low-thermal time constant amorphous silicon-based 320 x 240 uncooled microbolometer IRFPA

    NASA Astrophysics Data System (ADS)

    Tissot, Jean-Luc; Chatard, Jean-Pierre; Fieque, Bruno; Legras, Olivier

    2005-01-01

    Uncooled infrared focal plane arrays are being developed for a wide range of thermal imaging applications. Developments are focused on the improvement of their sensitivity enabling the possibility of reducing the pixel pitch in order to decrease the total system size and weight by using smaller optics. We present the ULIS second generation technology used for producing 320 x 240 (384 x 288) and 160 x 120 IRFPA with a pixel pitch of 35 μm. This enhanced technology was developed by CEA / LETI and has been transferred to ULIS in 2003. The device architecture will be described. This device is well adapted to high volume military applications (i.e. thermal weapons sight, enhanced driver vision) and commercial applications (i.e. predictive maintenance, firefighting, thermography, medical,...) where specifications are the result of a trade-off between pixel pitch, performance and system weight. We have developed for these devices low cost packages. IRFPA electro-optical characterization is presented.

  4. Enhanced amorphous silicon technology for 320 x 240 microbolometer arrays with a pitch of 35 μm

    NASA Astrophysics Data System (ADS)

    Mottin, Eric; Martin, Jean-Luc; Ouvrier-Buffet, Jean-Louis; Vilain, Michel; Bain, Astrid; Yon, Jean-Jacques; Tissot, Jean-Luc; Chatard, Jean-Pierre

    2001-10-01

    LETI LIR has been involved in Amorphous Silicon uncooled microbolometer development for years. This technology is now in production at Sofradir and first delivery have already been done to customers. From our background in modeling and material mastering LETI/LIR concentrate now on performance enhancement. This is a key point for cost reduction due to the fact that signal to noise ratio enhancement will allow us to decrease the pitch. A new approach of packaging is also described in this paper and first results are displayed. A new technological stack of amorphous silicon fully compatible with industrial process is presented. Electro-optical results obtained from an IRCMOS 320 X 240 with 35 μm pitch are presented. NETD close to 35 mK has been obtained with our new embodiment of amorphous silicon microbolometer technology.

  5. LEC system development

    SciTech Connect

    Halbert, D.D.

    1984-03-01

    The Lajet Energy Company (LEC) 460 is described. A parabolic dish which incorporates a microprocessor to automatically point it toward the Sun from sunrise to sunset is used. The dish is composed of a set of mirrors (made of reflective polymeric film) which focus and concentrate the Sun's energy on a receiver, producing intense but controlled amounts of heat. The LEC 460 employs a design concept that permits the use of common and low cost materials. All major structural components are fabricated from low carbon, low alloy steel using methods adaptable to mass production. The mirrors are supported on a steel tubing frame. This frame is attached near its center of gravity to a cantilevered support structure. The mirrors and frame are counterbalanced by the weight of the receiver, thus reducing the energy needed to move the collector (parasitic load) and allowing movement on two axes. Each LEC 460 solar concentrator contains a reflective array consisting of twenty four 60 inch diameter mirrors.

  6. Improving LEC incentive regulation plans. [local exchange carriers (LEC)

    SciTech Connect

    Kraemer, J.S. )

    1991-02-01

    This article recommends improving local exchange carriers (LEC) incentive regulation plans. The benefits of incentive regulation to customers/ratepayers, stockholders, LEC management, and regulators is reviewed. The potential pitfalls in recession risk, investment decisions and pricing inflexibility are examined. A review of the various forms of modified rate of return incentive regulation is included as a way to examine the characteristics needed for a successful incentive regulation plan.

  7. Recent development of ultra small pixel uncooled focal plane arrays at DRS

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Skidmore, George D.; Howard, Christopher; Han, C. J.; Wood, Lewis; Peysha, Doug; Williams, Eric; Trujillo, Carlos; Emmett, Jeff; Robas, Gary; Jardine, Daniel; Wan, C.-F.; Clarke, Elwood

    2007-04-01

    DRS is a major supplier of the 25μm pixel pitch 640x480 and 320x240 infrared uncooled focal plane arrays (UFPAs) and camera products for commercial and military markets. The state-of-the-art 25μm pixel focal plane arrays currently in production provide excellent performance for soldier thermal weapon sights (TWS), vehicle driver vision enhancers (DVE), and aerial surveillance and industrial thermograph applications. To further improve sensor resolution and reduce the sensor system size, weight and cost, it is highly desired to reduce the UFPA pixel size. However, the 17μm pixel FPA presents significant design and fabrication challenges as compared with 25μm pixel FPAs. The design objectives, engineering trade-offs, and performance goals will be discussed. This paper presents an overview of the 17μm microblometer uncooled focal plane arrays and sensor electronics production and development activities at DRS. The 17 μm pixel performance data from several initial fabrication lots will be summarized. Relevant 25μm pixel performance data are provided for comparison. Thermal images and video from the 17μm pixel 640x480 UFPA will also be presented.

  8. Caenorhabditis elegans galectins LEC-6 and LEC-10 interact with similar glycoconjugates in the intestine.

    PubMed

    Maduzia, Lisa L; Yu, Evan; Zhang, Yinhua

    2011-02-11

    Galectins are a family of metazoan proteins that show binding to various β-galactoside-containing glycans. Because of a lack of proper tools, the interaction of galectins with their specific glycan ligands in the cells and tissues are largely unknown. We have investigated the localization of galectin ligands in Caenorhabditis elegans using a novel technology that relies on the high binding specificity between galectins and their endogenous ligands. Fluorescently labeled recombinant galectin fusions are found to bind to ligands located in diverse tissues including the intestine, pharynx, and the rectal valve. Consistent with their role as galactoside-binding proteins, the interaction with their ligands is inhibited by galactose or lactose. Two of the galectins, LEC-6 and LEC-10, recognize ligands that co-localize along the intestinal lumen. The ligands for LEC-6 and LEC-10 are absent in three glycosylation mutants bre-1, fut-8, and galt-1, which have been shown to be required to synthesize the Gal-β1,4-Fuc modifications of the core N-glycans unique to C. elegans and several other invertebrates. Both galectins pull down the same set of glycoproteins in a manner dependent on the presence of these carbohydrate modifications. Endogenous LEC-6 and LEC-10 are expressed in the intestinal cells, but they are localized to different subcellular compartments that do not appear to overlap with each other or with the location of their glycan targets. An altered subcellular distribution of these ligands is found in mutants lacking both galectins. These results suggest a model where LEC-6 and LEC-10 interact with glycoproteins through specific glycans to regulate their cellular fate. PMID:21115491

  9. 47 CFR 51.703 - Reciprocal compensation obligation of LECs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Reciprocal compensation obligation of LECs. 51.703 Section 51.703 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Reciprocal Compensation for Transport and Termination...

  10. Genomic Rearrangements and Functional Diversification of lecA and lecB Lectin-Coding Regions Impacting the Efficacy of Glycomimetics Directed against Pseudomonas aeruginosa.

    PubMed

    Boukerb, Amine M; Decor, Aude; Ribun, Sébastien; Tabaroni, Rachel; Rousset, Audric; Commin, Loris; Buff, Samuel; Doléans-Jordheim, Anne; Vidal, Sébastien; Varrot, Annabelle; Imberty, Anne; Cournoyer, Benoit

    2016-01-01

    LecA and LecB tetrameric lectins take part in oligosaccharide-mediated adhesion-processes of Pseudomonas aeruginosa. Glycomimetics have been designed to block these interactions. The great versatility of P. aeruginosa suggests that the range of application of these glycomimetics could be restricted to genotypes with particular lectin types. The likelihood of having genomic and genetic changes impacting LecA and LecB interactions with glycomimetics such as galactosylated and fucosylated calix[4]arene was investigated over a collection of strains from the main clades of P. aeruginosa. Lectin types were defined, and their ligand specificities were inferred. These analyses showed a loss of lecA among the PA7 clade. Genomic changes impacting lec loci were thus assessed using strains of this clade, and by making comparisons with the PAO1 genome. The lecA regions were found challenged by phage attacks and PAGI-2 (genomic island) integrations. A prophage was linked to the loss of lecA. The lecB regions were found less impacted by such rearrangements but greater lecB than lecA genetic divergences were recorded. Sixteen combinations of LecA and LecB types were observed. Amino acid variations were mapped on PAO1 crystal structures. Most significant changes were observed on LecBPA7, and found close to the fucose binding site. Glycan array analyses were performed with purified LecBPA7. LecBPA7 was found less specific for fucosylated oligosaccharides than LecBPAO1, with a preference for H type 2 rather than type 1, and Lewis(a) rather than Lewis(x). Comparison of the crystal structures of LecBPA7 and LecBPAO1 in complex with Lewis(a) showed these changes in specificity to have resulted from a modification of the water network between the lectin, galactose and GlcNAc residues. Incidence of these modifications on the interactions with calix[4]arene glycomimetics at the cell level was investigated. An aggregation test was used to establish the efficacy of these ligands. Great

  11. Genomic Rearrangements and Functional Diversification of lecA and lecB Lectin-Coding Regions Impacting the Efficacy of Glycomimetics Directed against Pseudomonas aeruginosa

    PubMed Central

    Boukerb, Amine M.; Decor, Aude; Ribun, Sébastien; Tabaroni, Rachel; Rousset, Audric; Commin, Loris; Buff, Samuel; Doléans-Jordheim, Anne; Vidal, Sébastien; Varrot, Annabelle; Imberty, Anne; Cournoyer, Benoit

    2016-01-01

    LecA and LecB tetrameric lectins take part in oligosaccharide-mediated adhesion-processes of Pseudomonas aeruginosa. Glycomimetics have been designed to block these interactions. The great versatility of P. aeruginosa suggests that the range of application of these glycomimetics could be restricted to genotypes with particular lectin types. The likelihood of having genomic and genetic changes impacting LecA and LecB interactions with glycomimetics such as galactosylated and fucosylated calix[4]arene was investigated over a collection of strains from the main clades of P. aeruginosa. Lectin types were defined, and their ligand specificities were inferred. These analyses showed a loss of lecA among the PA7 clade. Genomic changes impacting lec loci were thus assessed using strains of this clade, and by making comparisons with the PAO1 genome. The lecA regions were found challenged by phage attacks and PAGI-2 (genomic island) integrations. A prophage was linked to the loss of lecA. The lecB regions were found less impacted by such rearrangements but greater lecB than lecA genetic divergences were recorded. Sixteen combinations of LecA and LecB types were observed. Amino acid variations were mapped on PAO1 crystal structures. Most significant changes were observed on LecBPA7, and found close to the fucose binding site. Glycan array analyses were performed with purified LecBPA7. LecBPA7 was found less specific for fucosylated oligosaccharides than LecBPAO1, with a preference for H type 2 rather than type 1, and Lewisa rather than Lewisx. Comparison of the crystal structures of LecBPA7 and LecBPAO1 in complex with Lewisa showed these changes in specificity to have resulted from a modification of the water network between the lectin, galactose and GlcNAc residues. Incidence of these modifications on the interactions with calix[4]arene glycomimetics at the cell level was investigated. An aggregation test was used to establish the efficacy of these ligands. Great variations

  12. Arabidopsis Lectin Receptor Kinases LecRK-IX.1 and LecRK-IX.2 Are Functional Analogs in Regulating Phytophthora Resistance and Plant Cell Death.

    PubMed

    Wang, Yan; Cordewener, Jan H G; America, Antoine H P; Shan, Weixing; Bouwmeester, Klaas; Govers, Francine

    2015-09-01

    L-type lectin receptor kinases (LecRK) are potential immune receptors. Here, we characterized two closely-related Arabidopsis LecRK, LecRK-IX.1 and LecRK-IX.2, of which T-DNA insertion mutants showed compromised resistance to Phytophthora brassicae and Phytophthora capsici, with double mutants showing additive susceptibility. Overexpression of LecRK-IX.1 or LecRK-IX.2 in Arabidopsis and transient expression in Nicotiana benthamiana increased Phytophthora resistance but also induced cell death. Phytophthora resistance required both the lectin domain and kinase activity, but for cell death, the lectin domain was not needed. Silencing of the two closely related mitogen-activated protein kinase genes NbSIPK and NbNTF4 in N. benthamiana completely abolished LecRK-IX.1-induced cell death but not Phytophthora resistance. Liquid chromatography-mass spectrometry analysis of protein complexes coimmunoprecipitated in planta with LecRK-IX.1 or LecRK-IX.2 as bait, resulted in the identification of the N. benthamiana ABC transporter NbPDR1 as a potential interactor of both LecRK. The closest homolog of NbPDR1 in Arabidopsis is ABCG40, and coimmunoprecipitation experiments showed that ABCG40 associates with LecRK-IX.1 and LecRK-IX.2 in planta. Similar to the LecRK mutants, ABCG40 mutants showed compromised Phytophthora resistance. This study shows that LecRK-IX.1 and LecRK-IX.2 are Phytophthora resistance components that function independent of each other and independent of the cell-death phenotype. They both interact with the same ABC transporter, suggesting that they exploit similar signal transduction pathways.

  13. New insights on the evolution of Leafy cotyledon1 (LEC1) type genes in vascular plants.

    PubMed

    Cagliari, Alexandro; Turchetto-Zolet, Andreia Carina; Korbes, Ana Paula; Maraschin, Felipe Dos Santos; Margis, Rogerio; Margis-Pinheiro, Marcia

    2014-01-01

    NF-Y is a conserved oligomeric transcription factor found in all eukaryotes. In plants, this regulator evolved with a broad diversification of the genes coding for its three subunits (NF-YA, NF-YB and NF-YC). The NF-YB members can be divided into Leafy Cotyledon1 (LEC1) and non-LEC1 types. Here we presented a comparative genomic study using phylogenetic analyses to validate an evolutionary model for the origin of LEC-type genes in plants and their emergence from non-LEC1-type genes. We identified LEC1-type members in all vascular plant genomes, but not in amoebozoa, algae, fungi, metazoa and non-vascular plant representatives, which present exclusively non-LEC1-type genes as constituents of their NF-YB subunits. The non-synonymous to synonymous nucleotide substitution rates (Ka/Ks) between LEC1 and non-LEC1-type genes indicate the presence of positive selection acting on LEC1-type members to the fixation of LEC1-specific amino acid residues. The phylogenetic analyses demonstrated that plant LEC1-type genes are evolutionary divergent from the non-LEC1-type genes of plants, fungi, amoebozoa, algae and animals. Our results point to a scenario in which LEC1-type genes have originated in vascular plants after gene expansion in plants. We suggest that processes of neofunctionalization and/or subfunctionalization were responsible for the emergence of a versatile role for LEC1-type genes in vascular plants, especially in seed plants. LEC1-type genes besides being phylogenetic divergent also present different expression profile when compared with non-LEC1-type genes. Altogether, our data provide new insights about the LEC1 and non-LEC1 evolutionary relationship during the vascular plant evolution.

  14. T-LECS: The Control Software System for MOIRCS

    NASA Astrophysics Data System (ADS)

    Yoshikawa, T.; Omata, K.; Konishi, M.; Ichikawa, T.; Suzuki, R.; Tokoku, C.; Katsuno, Y.; Nishimura, T.

    2006-07-01

    MOIRCS (Multi-Object Infrared Camera and Spectrograph) is a new instrument for the Subaru Telescope. We present the system design of the control software system for MOIRCS, named T-LECS (Tohoku University - Layered Electronic Control System). T-LECS is a PC-Linux based network distributed system. Two PCs equipped with the focal plane array system operate two HAWAII2 detectors, respectively, and another PC is used for user interfaces and a database server. Moreover, these PCs control various devices for observations distributed on a TCP/IP network. T-LECS has three interfaces; interfaces to the devices and two user interfaces. One of the user interfaces is to the integrated observation control system (Subaru Observation Software System) for observers, and another one provides the system developers the direct access to the devices of MOIRCS. In order to help the communication between these interfaces, we employ an SQL database system.

  15. Smart pixels

    NASA Astrophysics Data System (ADS)

    Seitz, Peter

    2004-09-01

    Semiconductor technology progresses at a relentless pace, making it possible to provide image sensors and each pixel with an increasing amount of custom analog and digital functionality. As experience with such photosensor functionality grows, an increasing variety of modular building blocks become available for smart pixels, single-chip digital cameras and functional image sensors. Examples include a non-linear pixel response circuit for high-dynamic range imaging with a dynamic range exceeding 180 dB, low-noise amplifiers and avalanche-effect pixels for high-sensitivity detection performance approaching single-photoelectron resolution, lock-in pixels for optical time-of-flight range cameras with sub-centimeter distance resolution and in-pixel demodulation circuits for optical coherence tomography imaging. The future is seen in system-on-a-chip machine vision cameras ("seeing chips"), post-processing with non-silicon materials for the extension of the detection range to the X-ray, ultraviolet and infrared spectrum, the use of organic semiconductors for low-cost large-area photonic microsystems, as well as imaging of fields other than electromagnetic radiation.

  16. 47 CFR 64.4002 - Notification obligations of LECs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... residential); (4) A statement indicating, to the extent appropriate, that the customer's telephone service... customer has moved from one location to another within a LEC's service territory); (ii) A change in... the customer's telephone service listing is not printed in a directory and is not available...

  17. PIXEL PUSHER

    NASA Technical Reports Server (NTRS)

    Stanfill, D. F.

    1994-01-01

    Pixel Pusher is a Macintosh application used for viewing and performing minor enhancements on imagery. It will read image files in JPL's two primary image formats- VICAR and PDS - as well as the Macintosh PICT format. VICAR (NPO-18076) handles an array of image processing capabilities which may be used for a variety of applications including biomedical image processing, cartography, earth resources, and geological exploration. Pixel Pusher can also import VICAR format color lookup tables for viewing images in pseudocolor (256 colors). This program currently supports only eight bit images but will work on monitors with any number of colors. Arbitrarily large image files may be viewed in a normal Macintosh window. Color and contrast enhancement can be performed with a graphical "stretch" editor (as in contrast stretch). In addition, VICAR images may be saved as Macintosh PICT files for exporting into other Macintosh programs, and individual pixels can be queried to determine their locations and actual data values. Pixel Pusher is written in Symantec's Think C and was developed for use on a Macintosh SE30, LC, or II series computer running System Software 6.0.3 or later and 32 bit QuickDraw. Pixel Pusher will only run on a Macintosh which supports color (whether a color monitor is being used or not). The standard distribution medium for this program is a set of three 3.5 inch Macintosh format diskettes. The program price includes documentation. Pixel Pusher was developed in 1991 and is a copyrighted work with all copyright vested in NASA. Think C is a trademark of Symantec Corporation. Macintosh is a registered trademark of Apple Computer, Inc.

  18. Pixel Paradise

    NASA Technical Reports Server (NTRS)

    1998-01-01

    PixelVision, Inc., has developed a series of integrated imaging engines capable of high-resolution image capture at dynamic speeds. This technology was used originally at Jet Propulsion Laboratory in a series of imaging engines for a NASA mission to Pluto. By producing this integrated package, Charge-Coupled Device (CCD) technology has been made accessible to a wide range of users.

  19. Recovery and recycling of limestone in LEC flue gas desulfurization

    SciTech Connect

    Gardner, N.C.; Adler, R.J.; Lin, Y.C.; Unger, M.E.; Lux, K.W. )

    1992-03-01

    Prudich et al. have proposed an attractive technology called Limestone Emission Control (LEC) for removing sulfur dioxide from flue gases. Beds of 1/8 inch wet limestone particles absorb the sulfur dioxide from the gases. Sulfates and sulfites deposit on the surfaces of the particles, limiting their utilization to about 20%. The unreacted portion of the limestone can be recovered by mechanical grinding and recycling, enabling high overall sorbent utilization. Favorable economic costs derive from small equipment, simplicity, and low sorbent cost. Our research concentrates on selecting and testing on a laboratory scale suitable candidate dry and wet grinding methods for recovering limestone in LEC flue from desulfurization. A wet grinding method based on the impeller fluidizer, a new type of slurry processor, receives special attention. The impeller fluidizer is a dosed cylindrical vessel with an impeller at one end. It combines the operations of wet grinding, washing, and transporting the spent and recovered limestone as an aqueous slurry.

  20. Zinc supplementation decreases hepatic copper accumulation in LEC rat: a model of Wilson's disease.

    PubMed

    Gonzalez, Blanca P Esparza; Niño Fong, Rodolfo; Gibson, Candace J; Fuentealba, I Carmen; Cherian, M George

    2005-01-01

    The effect of dietary zinc (Zn) supplementation on copper (Cu)-induced liver damage was investigated in Long-Evans Cinnamon rats (LEC), a model for Wilson's disease (WD). Four-week-old LEC (N=64) and control Long-Evans (LE) (N=32) female rats were divided into two groups; one group was fed with a Zn-supplemented diet (group I) and the other was given a normal rodent diet (group II). LEC rats were killed at 6, 8, 10, 12, 18, and 20 wk of age; the LE control rats were killed at 6, 12, 18, and 20 wk of age. Cu concentration in the liver was reduced in LEC rats fed the Zn-supplemented diet compared with LEC rats on the normal diet between 6 and 18 wk of age. Metallothionein (MT) concentration in the livers of LEC rats in group I increased between 12 and 20 wk of age, whereas hepatic MT concentration in LEC rats from group II decreased after 12 wk. Hepatocyte apoptosis, as determined by TUNEL, was reduced in Zn-supplemented LEC rats at all ages. Cholangiocellular carcinoma was observed only in LEC rats in group II at wk 20. These results suggest that Zn supplementation can reduce hepatic Cu concentration and delay the onset of clinical and pathological changes of Cu toxicity in LEC rats. Although the actual mechanism of protection is unknown, it could be explained by sequestration of dietary Cu by intestinal MT, induced by high dietary Zn content.

  1. Recovery and recycling of limestone in LEC flue gas desulfurization

    SciTech Connect

    Gardner, N.C.; Boo, J.Y.; Culver, L. )

    1992-09-01

    Prudich et. al. have proposed an attractive technology called Limestone Emission Control (LEC) for removing sulfur dioxide from flue gases. Beds of 1/8 inch wet limestone particles absorb the sulfur dioxide from the gases on contact. Sulfite and sulfate salts deposit on the surface of the particles; however, the gas never reaches the interior, limiting the limestone utilization to approximately 20% or less. The unreacted portion of the limestone can be recovered by mechanical grinding and recycling, enabling high overall sorbent utilization. Favorable economics are derived from small equipment, simplicity, and low sorbent costs. This project is a wet method for grinding and recovering the spent limestone from the LEC process, utilizing an impeller fluidizer, a new type of slurry processor. It consists of a cylindrical vessel with an impeller at one end. The impeller, driven at high rpm, concentrates the gravel size limestone in a rotating torus at the top of the cylinder, where the coating is abraded off by particle-particle impaction. The impeller generates sufficient pressure head to serve as a slurry pump. It combines the operation of wet grinding, washing, and transporting the spent and recovered limestone as an aqueous slurry. The fluidizer may be advantageous over dry grinding in the aspects of sharpness of separation, transport convenience, equipment erosion, and sorption bed cementation.

  2. 47 CFR 69.711 - Channel terminations between LEC end offices and customer premises.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... and customer premises. 69.711 Section 69.711 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... terminations between LEC end offices and customer premises. (a) Scope. This paragraph governs requests for pricing flexibility with respect to channel terminations between LEC end offices and customer premises....

  3. Abnormal hepatic copper accumulation of spheroid composed of liver cells from LEC rats in vitro.

    PubMed

    Ueno, K; Yoshizawa, M; Satoh, T; Yoneda, S; Ohmichi, M; Yamazaki, M; Mori, Y; Suzuki, K T

    1995-11-01

    The LEC rat is a mutant strain displaying hereditary hepatitis, and shows abnormal accumulation of copper (Cu) similar to that occurring in Wilson's disease. We prepared a multicellular spheroid composed of LEC rat liver cells to investigate the mechanism for abnormal accumulation of Cu. These multicellular spheroids were prepared by detaching the monolayer on the collagen-conjugated thermo-responsive polymer coated culture dish at a temperature below the critical solution temperature and culturing on the non-adhesive substratum. Long-term cultured spheroids of LEC rat liver cells as well as SD rat liver cells were attempted. Non-parenchymal cells obtained by collagenase perfusion from the LEC liver were fewer than those from the SD liver. Cells from the LEC rat, over 11 weeks of age, did not form a cell sheet; however, a mixture of parenchymal cells from LEC rats over aged 11 weeks and non-parenchymal cells from SD rats of any age yielded intact spheroids. We examined the toxicity, the accumulation and distribution of Cu in spheroids. The accumulation of Cu in LEC spheroids was higher than that in SD spheroids. Results suggest that spheroids consisting of LEC liver cells are useful as an alternative model to in vivo tests to investigate the mechanism for abnormal accumulation of Cu in liver.

  4. 47 CFR 69.709 - Dedicated transport and special access services other than channel terminations between LEC end...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... other than channel terminations between LEC end offices and customer premises. 69.709 Section 69.709... terminations between LEC end offices and customer premises. (a) Scope. This paragraph governs requests for..., competitors unaffiliated with the price cap LEC have collocated: (1) In fifteen percent of the...

  5. Pixel Perfect

    SciTech Connect

    Perrine, Kenneth A.; Hopkins, Derek F.; Lamarche, Brian L.; Sowa, Marianne B.

    2005-09-01

    cubic warp. During image acquisitions, the cubic warp is evaluated by way of forward differencing. Unwanted pixelation artifacts are minimized by bilinear sampling. The resulting system is state-of-the-art for biological imaging. Precisely registered images enable the reliable use of FRET techniques. In addition, real-time image processing performance allows computed images to be fed back and displayed to scientists immediately, and the pipelined nature of the FPGA allows additional image processing algorithms to be incorporated into the system without slowing throughput.

  6. An evaluation of the LEC-460 solar collector

    SciTech Connect

    Strachan, J.W.

    1987-09-01

    The optical performance of the LaJet Energy Corporation's membrane faceted concentrator, Model LEC-460, was evaluated at Sandia National Laboratories, Albuquerque, using a fluxmapper, a device that measures flux intensity in the aperture plane of the collector with a movable Kendall radiometer. Three-dimensional flux intensity plots and flux contour maps were produced from the data, and numerical integration of the data was performed to obtain an estimate of the total integrated power into the aperture plane. The test results, normalized to a reference insolation value of 0.1 W/cm/sup 2/, indicated a peak flux of 172 W/cm/sup 2/ and a total integrated power of 30.2 kW. The net efficiency of the collector in a clean mirror condition was estimated to be 77.4%.

  7. Decreased tumorigenicity correlates with expression of altered cell surface carbohydrates in Lec9 CHO cells.

    PubMed Central

    Ripka, J; Shin, S; Stanley, P

    1986-01-01

    To investigate a role for surface carbohydrates in cellular malignancy, 15 different glycosylation-defective CHO cell mutants were examined for their tumorigenic and metastatic capacities after subcutaneous injection into nude mice. Most of the glycosylation mutants displayed similar or slightly decreased tumorigenicity compared with parental CHO cells. Neither parental CHO cells nor any of the mutants were observed to metastasize. However, independent isolates of one mutant type, Lec9, showed a dramatic reduction in tumor formation. The altered carbohydrates expressed at the surface of Lec9 cells appeared to be responsible for their loss of tumorigenicity, because revertants for lectin resistance were able to form tumors, and a double mutant (Lec9.Lec1) that expressed a Lec1 glycosylation phenotype also formed tumors. Finally, Lec9 cells were able to form tumors in gamma-irradiated nude mice, suggesting that recognition by an irradiation-sensitive host cell(s) was responsible for their reduced tumorigenicity in untreated nude mice. PMID:3785164

  8. Pseudomonas aeruginosa lectin LecB inhibits tissue repair processes by triggering β-catenin degradation

    PubMed Central

    Cott, Catherine; Thuenauer, Roland; Landi, Alessia; Kühn, Katja; Juillot, Samuel; Imberty, Anne; Madl, Josef; Eierhoff, Thorsten; Römer, Winfried

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that induces severe lung infections such as ventilator-associated pneumonia and acute lung injury. Under these conditions, the bacterium diminishes epithelial integrity and inhibits tissue repair mechanisms, leading to persistent infections. Understanding the involved bacterial virulence factors and their mode of action is essential for the development of new therapeutic approaches. In our study we discovered a so far unknown effect of the P. aeruginosa lectin LecB on host cell physiology. LecB alone was sufficient to attenuate migration and proliferation of human lung epithelial cells and to induce transcriptional activity of NF-κB. These effects are characteristic of impaired tissue repair. Moreover, we found a strong degradation of β-catenin, which was partially recovered by the proteasome inhibitor lactacystin. In addition, LecB induced loss of cell–cell contacts and reduced expression of the β-catenin targets c-myc and cyclin D1. Blocking of LecB binding to host cell plasma membrane receptors by soluble l-fucose prevented these changes in host cell behavior and signaling, and thereby provides a powerful strategy to suppress LecB function. Our findings suggest that P. aeruginosa employs LecB as a virulence factor to induce β-catenin degradation, which then represses processes that are directly linked to tissue recovery. PMID:26862060

  9. Recent improvements and developments in uncooled systems at BAE SYSTEMS North America

    NASA Astrophysics Data System (ADS)

    Backer, Brian S.; Butler, Neal R.; Kohin, Margaret; Gurnee, Mark N.; Whitwam, Jason T.; Breen, Tom

    2002-08-01

    BAE SYSTEMS has designed and developed MicroIR microbolometer focal plane arrays (FPAs) in three formats (160x120, 320x240, and 640x480) and with two different pixel sizes (46micrometers and 28micrometers ). In addition to successfully demonstrating these FPA technologies, BAE SYSTEMS has produced and delivered thousands of 320x240 (46micrometers pixel) imaging modules and camera cores for military, thermography, firefighting, security and numerous other applications throughout the world. Recently, BAE SYSTEMS has started production deliveries of 160x120 (46micrometers ) systems, demonstrated 320x240 and 640x480 second-generation (28micrometers ) imaging, and demonstrated second-generation thermoelectric cooler-less operation. This paper discusses these recent accomplishments and, when possible, provides quantitative NETD and performance data for our newly developed FPAs and systems. Video will be shown to demonstrate sensor performance capabilities.

  10. Single CRD containing lectin from Macrobrachium rosenbergii (MrLec) participates in innate immunity against pathogen infections.

    PubMed

    Huang, Xin; Li, Wen; Jin, Min; Ma, Fu-Tong; Huang, Ying; Shi, Yan-Ru; Zhao, Ling-Ling; Feng, Jin-Ling; Ren, Qian; Wang, Wen

    2016-04-01

    As a type of pattern-recognition proteins, lectins perform important functions in the innate immunity of crustaceans, including prawns. Although several reports showed that C-type lectin domain family (CLEC) importantly functions in host-pathogen interactions, limited research has focused on CLEC in Macrobrachium rosenbergii. In the present study, a new single CRD containing CLEC (designated as MrLec) was reported in freshwater prawns, M. rosenbergii. The full-length cDNA of MrLec consisted of 1027 bp with an open reading frame of 801 bp, which encoded a peptide of 266 amino acid residues. Genomic sequence for MrLec was also obtained from the M. rosenbergii, which contain 4 exons and 3 introns. MrLec was found to contain a single carbohydrate-recognition domain with an EPN motif. MrLec was ubiquitously distributed in various tissues of a normal prawn, particularly in the hepatopancreas and gills. MrLec expression in the gills was significantly upregulated after a challenge with Vibrio parahaemolyticus and downregulated at 24 h after MrLec RNA interference (MrLec-RNAi). The expression levels of some AMPs, including antilipopolysaccharide factor 1 (Alf1) and lysozyme 2 (Lyso2), also markedly decreased after MrLec-RNAi. Recombinant MrLec can agglutinate (Ca(2+)-dependent) and bind both Gram-negative and Gram-positive bacteria. Results suggested that MrLec participates in the recognition of invading pathogens and functions in the immune response of prawn against pathogen infections.

  11. A posteriori error estimates for the Johnson–Nédélec FEM–BEM coupling

    PubMed Central

    Aurada, M.; Feischl, M.; Karkulik, M.; Praetorius, D.

    2012-01-01

    Only very recently, Sayas [The validity of Johnson–Nédélec's BEM-FEM coupling on polygonal interfaces. SIAM J Numer Anal 2009;47:3451–63] proved that the Johnson–Nédélec one-equation approach from [On the coupling of boundary integral and finite element methods. Math Comput 1980;35:1063–79] provides a stable coupling of finite element method (FEM) and boundary element method (BEM). In our work, we now adapt the analytical results for different a posteriori error estimates developed for the symmetric FEM–BEM coupling to the Johnson–Nédélec coupling. More precisely, we analyze the weighted-residual error estimator, the two-level error estimator, and different versions of (h−h/2)-based error estimators. In numerical experiments, we use these estimators to steer h-adaptive algorithms, and compare the effectivity of the different approaches. PMID:22347772

  12. Mechanism of enhanced lipid peroxidation in the liver of Long-Evans cinnamon (LEC) rats.

    PubMed

    Yamamoto, H; Hirose, K; Hayasaki, Y; Masuda, M; Kazusaka, A; Fujita, S

    1999-11-01

    The Long-Evans Cinnamon (LEC) rat is a mutant strain of rats that accumulate copper (Cu) in the liver in much the same way as individuals who suffer from Wilson's disease (WD) and has been suggested as a model for this disease. Lipid peroxidation (LPO) is considered to be involved in the toxic action of Cu in the livers of LEC rats. We investigated the mechanism of LPO in the livers of LEC rats showing apparent signs of hepatitis. Several-fold higher LPO levels were observed in post-mitochondrial supernatant (S-9) fraction of livers from hepatitic LEC rats than in those from Wistar rats. To mimic living cells, we introduced NADPH-generating system (NADPH-gs) into the S-9 incubation system. Thus was ensured a constant supply of NADPH to vital enzymes that may be directly or indirectly involved in the generation and/or elimination of reactive oxygen species (ROSs), such as glutathione reductase (GSSG-R), which require NADPH for their reactions. The levels of LPO in liver S-9 from hepatitic LEC rats were further increased by incubating liver S-9 at 37 degrees C in the presence of NADPH-gs. This increase was inhibited by EDTA, butylated hydroxytoluene (BHT), and catalase (CAT), suggesting that some metal, most likely the accumulated Cu, and ROSs derived from hydrogen peroxide (H2O2) are involved in the increased levels of LPO in the livers of hepatitic LEC rats. The requirement of NADPH-gs for enhanced LPO in the livers of hepatitic LEC rats indicates the consumption of NADPH during reactions leading to LPO. It is known that H2O2, and consequently hydroxyl radical are generated during Cu-catalyzed glutathione (GSH) oxidation. The cyclic regeneration of GSH from GSSG by NADPH-dependent GSSG-R in the presence of NADPH-gs may cause sustained generation of hydroxyl radical in the presence of excess free Cu. The generation of H2O2 in S-9 fraction of livers from hepatitic LEC rats was observed to be significantly higher than that in S-9 fraction of livers from non

  13. PixelLearn

    NASA Technical Reports Server (NTRS)

    Mazzoni, Dominic; Wagstaff, Kiri; Bornstein, Benjamin; Tang, Nghia; Roden, Joseph

    2006-01-01

    PixelLearn is an integrated user-interface computer program for classifying pixels in scientific images. Heretofore, training a machine-learning algorithm to classify pixels in images has been tedious and difficult. PixelLearn provides a graphical user interface that makes it faster and more intuitive, leading to more interactive exploration of image data sets. PixelLearn also provides image-enhancement controls to make it easier to see subtle details in images. PixelLearn opens images or sets of images in a variety of common scientific file formats and enables the user to interact with several supervised or unsupervised machine-learning pixel-classifying algorithms while the user continues to browse through the images. The machinelearning algorithms in PixelLearn use advanced clustering and classification methods that enable accuracy much higher than is achievable by most other software previously available for this purpose. PixelLearn is written in portable C++ and runs natively on computers running Linux, Windows, or Mac OS X.

  14. 47 CFR 52.23 - Deployment of long-term database methods for number portability by LECs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Deployment of long-term database methods for... database methods for number portability by LECs. (a) Subject to paragraphs (b) and (c) of this section, all... LECs must provide a long-term database method for number portability in the 100 largest...

  15. 47 CFR 52.23 - Deployment of long-term database methods for number portability by LECs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Deployment of long-term database methods for... database methods for number portability by LECs. (a) Subject to paragraphs (b) and (c) of this section, all... LECs must provide a long-term database method for number portability in the 100 largest...

  16. 47 CFR 52.23 - Deployment of long-term database methods for number portability by LECs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Deployment of long-term database methods for... database methods for number portability by LECs. (a) Subject to paragraphs (b) and (c) of this section, all... LECs must provide a long-term database method for number portability in the 100 largest...

  17. 47 CFR 52.23 - Deployment of long-term database methods for number portability by LECs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Deployment of long-term database methods for... database methods for number portability by LECs. (a) Subject to paragraphs (b) and (c) of this section, all... LECs must provide a long-term database method for number portability in the 100 largest...

  18. 47 CFR 52.23 - Deployment of long-term database methods for number portability by LECs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Deployment of long-term database methods for... database methods for number portability by LECs. (a) Subject to paragraphs (b) and (c) of this section, all... LECs must provide a long-term database method for number portability in the 100 largest...

  19. Therapeutic effects of tetrathiomolybdate on hepatic dysfunction occurring naturally in Long-Evans Cinnamon (LEC) rats: a bona fide animal model for Wilson's disease.

    PubMed

    Sugawara, N; Lai, Y R; Sugawara, C

    1999-02-01

    Long-Evans Cinnamon (LEC) rats were fed a diet containing 7 ppm Cu and 30 ppm Cu from 60 days after birth. Fischer (Fischer group) and LEC (LEC-control group) rats fed a 7 ppm Cu diet showed normal growth throughout the whole period (60 to 125 days after birth). On the other hand, LEC rats fed the 30 ppm Cu diet had decreased body weight and showed slight jaundice at around 100 days after birth. Tetrathiomolybdate (TTM, 10 mg/kg bw) was injected sub-cutaneously at 101 and 105 days after birth into half of the LEC rats fed the 30 ppm Cu diet. LEC rats given TTM (LEC+TTM group) recovered their body weight and the jaundice rapidly disappeared. However, LEC rats without TTM (LEC-TTM group) had sharply decreased body weight and showed severe jaundice at 103 days after birth. The hepatic Cu concentration in LEC+TTM rats (460 micrograms/g) exceeded that of LEC-control rats (330 micrograms/g) at 125 days after birth. Our data suggest that TTM is effective for treatment of acute hepatic injury in the LEC rat.

  20. 47 CFR 69.711 - Channel terminations between LEC end offices and customer premises.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) ACCESS CHARGES Pricing Flexibility § 69.711 Channel... pricing flexibility with respect to channel terminations between LEC end offices and customer premises. (b) Phase I triggers. To obtain Phase I pricing flexibility, as specified in § 69.727(a) of this part,...

  1. 47 CFR 69.711 - Channel terminations between LEC end offices and customer premises.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) ACCESS CHARGES Pricing Flexibility § 69.711 Channel... pricing flexibility with respect to channel terminations between LEC end offices and customer premises. (b) Phase I triggers. To obtain Phase I pricing flexibility, as specified in § 69.727(a) of this part,...

  2. 47 CFR 69.711 - Channel terminations between LEC end offices and customer premises.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) ACCESS CHARGES Pricing Flexibility § 69.711 Channel... pricing flexibility with respect to channel terminations between LEC end offices and customer premises. (b) Phase I triggers. To obtain Phase I pricing flexibility, as specified in § 69.727(a) of this part,...

  3. 47 CFR 69.711 - Channel terminations between LEC end offices and customer premises.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) ACCESS CHARGES Pricing Flexibility § 69.711 Channel... pricing flexibility with respect to channel terminations between LEC end offices and customer premises. (b) Phase I triggers. To obtain Phase I pricing flexibility, as specified in § 69.727(a) of this part,...

  4. 47 CFR 51.705 - Incumbent LECs' rates for transport and termination.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Incumbent LECs' rates for transport and termination. 51.705 Section 51.705 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Reciprocal Compensation for Transport and Termination...

  5. 47 CFR 51.707 - Default proxies for incumbent LECs' transport and termination rates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Default proxies for incumbent LECs' transport and termination rates. 51.707 Section 51.707 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Reciprocal Compensation for Transport...

  6. The Theobroma cacao B3 domain transcription factor TcLEC2 plays a duel role in control of embryo development and maturation

    PubMed Central

    2014-01-01

    Background The Arabidopsis thaliana LEC2 gene encodes a B3 domain transcription factor, which plays critical roles during both zygotic and somatic embryogenesis. LEC2 exerts significant impacts on determining embryogenic potential and various metabolic processes through a complicated genetic regulatory network. Results An ortholog of the Arabidopsis Leafy Cotyledon 2 gene (AtLEC2) was characterized in Theobroma cacao (TcLEC2). TcLEC2 encodes a B3 domain transcription factor preferentially expressed during early and late zygotic embryo development. The expression of TcLEC2 was higher in dedifferentiated cells competent for somatic embryogenesis (embryogenic calli), compared to non-embryogenic calli. Transient overexpression of TcLEC2 in immature zygotic embryos resulted in changes in gene expression profiles and fatty acid composition. Ectopic expression of TcLEC2 in cacao leaves changed the expression levels of several seed related genes. The overexpression of TcLEC2 in cacao explants greatly increased the frequency of regeneration of stably transformed somatic embryos. TcLEC2 overexpressing cotyledon explants exhibited a very high level of embryogenic competency and when cultured on hormone free medium, exhibited an iterative embryogenic chain-reaction. Conclusions Our study revealed essential roles of TcLEC2 during both zygotic and somatic embryo development. Collectively, our evidence supports the conclusion that TcLEC2 is a functional ortholog of AtLEC2 and that it is involved in similar genetic regulatory networks during cacao somatic embryogenesis. To our knowledge, this is the first detailed report of the functional analysis of a LEC2 ortholog in a species other then Arabidopsis. TcLEC2 could potentially be used as a biomarker for the improvement of the SE process and screen for elite varieties in cacao germplasm. PMID:24758406

  7. High density pixel array

    NASA Technical Reports Server (NTRS)

    Wiener-Avnear, Eliezer (Inventor); McFall, James Earl (Inventor)

    2004-01-01

    A pixel array device is fabricated by a laser micro-milling method under strict process control conditions. The device has an array of pixels bonded together with an adhesive filling the grooves between adjacent pixels. The array is fabricated by moving a substrate relative to a laser beam of predetermined intensity at a controlled, constant velocity along a predetermined path defining a set of grooves between adjacent pixels so that a predetermined laser flux per unit area is applied to the material, and repeating the movement for a plurality of passes of the laser beam until the grooves are ablated to a desired depth. The substrate is of an ultrasonic transducer material in one example for fabrication of a 2D ultrasonic phase array transducer. A substrate of phosphor material is used to fabricate an X-ray focal plane array detector.

  8. Selecting Pixels for Kepler Downlink

    NASA Technical Reports Server (NTRS)

    Bryson, Stephen T.; Jenkins, Jon M.; Klaus, Todd C.; Cote, Miles T.; Quintana, Elisa V.; Hall, Jennifer R.; Ibrahim, Khadeejah; Chandrasekaran, Hema; Caldwell, Douglas A.; Van Cleve, Jeffrey E.; Haas, Michael R.

    2010-01-01

    The Kepler mission monitors > 100,000 stellar targets using 42 2200 1024 pixel CCDs. Bandwidth constraints prevent the downlink of all 96 million pixels per 30-minute cadence, so the Kepler spacecraft downlinks a specified collection of pixels for each target. These pixels are selected by considering the object brightness, background and the signal-to-noise of each pixel, and are optimized to maximize the signal-to-noise ratio of the target. This paper describes pixel selection, creation of spacecraft apertures that efficiently capture selected pixels, and aperture assignment to a target. Diagnostic apertures, short-cadence targets and custom specified shapes are discussed.

  9. Performance of Jay/LEC Fields Unit under mature waterflood and early tertiary operations

    SciTech Connect

    Langston, E.P.; Shirer, J.A.

    1983-10-01

    Secondary oil recovery for the Jay/Little Escambia Creek (LEC) Fields Unit will exceed initial estimates by 27 MMB (4.3 x 10 m) due to innovative reservoir management based on a comprehensive surveillance program and detailed reservoir description data. The mature waterflood was phased-in to a tertiary recovery project in 1981 and early performance is generally consistent with the planning study which predicted that 47 MMB (7.5 x 10 m) of tertiary oil will be recovered.

  10. Performance of Jay/LEC fields unit under mature waterflood and early tertiary operations

    SciTech Connect

    Langston, E.P.; Shirer, J.A.

    1983-01-01

    Secondary oil recovery for the Jay/Little Escambia Creek (LEC) fields unit will exceed initial estimates by 27 million bbl due to innovative reservoir management based on a comprehensive surveillance program and detailed reservoir description data. The mature waterflood was phased-in to a tertiary recovery project in 1981 and early performance is generally consistent with the planning study which predicted that 47 million bbl of tertiary oil will be recovered.

  11. Spectroscopy of defects induced by ohmic contact preparation in LEC GaAs particle detectors

    SciTech Connect

    Castaldini, A.; Cavallini, A.; Canali, C.; Nava, F.

    1996-12-01

    Semi-insulating LEC gallium arsenide particle detectors were realized with differently manufactured ohmic contacts to improve their performances and possibly avoid injection effects often experienced when the detectors work in full depletion conditions. I-V and C-V measurements on Schottky structures were carried out. Photo-induced current transient spectroscopy and also photo-deep level transient spectroscopy investigations, performed on both planar and Schottky structures, identified electron and hole traps. Detector performances were correlated to defects action.

  12. Fucofullerenes as tight ligands of RSL and LecB, two bacterial lectins.

    PubMed

    Buffet, Kevin; Gillon, Emilie; Holler, Michel; Nierengarten, Jean-François; Imberty, Anne; Vincent, Stéphane P

    2015-06-21

    A series of water-soluble glycofullerenes containing up to 24 fucose residues have been prepared. These compounds were tested against the two bacterial fucose-binding lectins LecB and RSL, and C60(E)12 bearing 24 fucose residues appeared to be the best known inhibitor of both lectins to date. We have shown that increasing both the valency and the length of the spacer between the central core and the peripheral sugars can be beneficial for the affinity.

  13. Structural basis of preferential binding of fucose-containing saccharide by the Caenorhabditis elegans galectin LEC-6.

    PubMed

    Makyio, Hisayoshi; Takeuchi, Tomoharu; Tamura, Mayumi; Nishiyama, Kazusa; Takahashi, Hideyo; Natsugari, Hideaki; Arata, Yoichiro; Kasai, Ken-Ichi; Yamada, Yusuke; Wakatsuki, Soichi; Kato, Ryuichi

    2013-07-01

    Galectins are a group of lectins that can bind carbohydrate chains containing β-galactoside units. LEC-6, a member of galectins of Caenorhabditis elegans, binds fucose-containing saccharides. We solved the crystal structure of LEC-6 in complex with galactose-β1,4-fucose (Galβ1-4Fuc) at 1.5 Å resolution. The overall structure of the protein and the identities of the amino-acid residues binding to the disaccharide are similar to those of other galectins. However, further structural analysis and multiple sequence alignment between LEC-6 and other galectins indicate that a glutamic acid residue (Glu67) is important for the preferential binding between LEC-6 and the fucose moiety of the Galβ1-4Fuc unit. Frontal affinity chromatography analysis indicated that the affinities of E67D and E67A mutants for Galβ1-4Fuc are lower than that of wild-type LEC-6. Furthermore, the affinities of Glu67 mutants for an endogenous oligosaccharide, which contains a Galβ1-4Fuc unit, are drastically reduced relative to that of the wild-type protein. We conclude that the Glu67 in the oligosaccharide-binding site assists the recognition of the fucose moiety by LEC-6.

  14. Multivalency effects on Pseudomonas aeruginosa biofilm inhibition and dispersal by glycopeptide dendrimers targeting lectin LecA.

    PubMed

    Bergmann, Myriam; Michaud, Gaëlle; Visini, Ricardo; Jin, Xian; Gillon, Emilie; Stocker, Achim; Imberty, Anne; Darbre, Tamis; Reymond, Jean-Louis

    2016-01-01

    The galactose specific lectin LecA partly mediates the formation of antibiotic resistant biofilms by Pseudomonas aeruginosa, an opportunistic pathogen causing lethal airways infections in immunocompromised and cystic fibrosis patients, suggesting that preventing LecA binding to natural saccharides might provide new opportunities for treatment. Here 8-fold (G3) and 16-fold (G4) galactosylated analogs of GalAG2, a tetravalent G2 glycopeptide dendrimer LecA ligand and P. aeruginosa biofilm inhibitor, were obtained by convergent chloroacetyl thioether (ClAc) ligation between 4-fold or 8-fold chloroacetylated dendrimer cores and digalactosylated dendritic arms. Hemagglutination inhibition, isothermal titration calorimetry and biofilm inhibition assays showed that G3 dendrimers bind LecA slightly better than their parent G2 dendrimers and induce complete biofilm inhibition and dispersal of P. aeruginosa biofilms, while G4 dendrimers show reduced binding and no biofilm inhibition. A binding model accounting for the observed saturation of glycopeptide dendrimer galactosyl groups and LecA binding sites is proposed based on the crystal structure of a G3 dendrimer LecA complex.

  15. Partial gene deletion in LEC rat: An animal model for Wilson disease

    SciTech Connect

    Wu, J.; Forbes, J.R.; Cox, D.W.

    1994-09-01

    Wilson disease is an inherited disorder of copper transport in which incorporation of copper into ceruloplasmin and excretion of copper into bile are greatly reduced. Copper accumulates to a toxic level in the liver and also in the brain and kidney, causing a spectrum of hepatic and neurological abnormalities. We have recently cloned the gene for Wilson disease (designated ATP7B), which encodes a putative copper-transporting P-type ATPase. The inbred mutant Long-Evans Cinnamon (LEC) rat strain shows similarity to Wilson disease in many clinical and biochemical features. We have cloned cDNAs for the rat homologue (Atp7b) of the human Wilson disease gene (ATP7B) and have shown that the two genes have {approximately}82% identity at the amino acid sequence level. Rat cDNA sequences were used to identify a partial deletion in the Atp7b gene in the LEC rat. The deletion removes at least 750 bp of the coding region at the 3{prime} end, which includes the crucial ATP binding domain and extends downstream of the gene. The proximal breakpoint has been precisely localized at the cDNA level. Our results provide convincing evidence that the LEC rat is an animal model for Wilson disease. This model will be important for studying liver pathophysiology, for developing therapy for Wilson disease, and for studying the pathway of copper transport and its possible interaction with other heavy metals.

  16. Background paper on electrical services provided by the Liberia Electricity Corporation (LEC)

    SciTech Connect

    Barron, W.F.; Hobbs, B.F.; Samuels, G.; Kawah, L.M.

    1985-07-01

    This report is one of a series of project papers providing background information for an assessment of energy options for Liberia, West Africa; it presents data on electrical services in Liberia (as of early 1983) with primary emphasis on the operations of the Liberia Electricity Corporation (LEC). The LEC is a semiautonomous agency owned by the Government of Liberia that has primary responsibility for generating electricity throughout Liberia. The LEC system consists of a central grid covering an area roughly 175 by 100 km with Monrovia as its focal point, and nine rural stations serving ten towns. The central grid has a total capacity of 177 MW (64 hydro and 113 diesel engines and gas turbines) and produced 378 million kWh in 1981. The rural stations with a total capacity of 13 MW (all diesels) produced 27 million kWh in 1981. Information provided by this paper includes historical sales data by customer class, growth in demand, hourly load data, petroleum consumption, prices, and problems. Major problems include uncollected bills, illegal hookups, inoperable generating equipment, and fuel shortages.

  17. STIS CCD Hot Pixel Annealing

    NASA Astrophysics Data System (ADS)

    Hernandez, Svea

    2013-10-01

    This purpose of this activity is to repair radiation induced hot pixel damage to theSTIS CCD by warming the CCD to the ambient instrument temperature and annealing radiation damaged pixels. Radiation damage creates hot pixels in the STIS CCD Detector. Many of these hot pixels can be repaired by warming the CCD from its normal operating temperature near-83 C to the ambient instrument temperature { +5 C} for several hours. The number of hot pixels repaired is a function of annealing temperature. The effectiveness of the CCD hot pixel annealing process is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects.

  18. Cloning and Characterization of 5′ Flanking Regulatory Sequences of AhLEC1B Gene from Arachis Hypogaea L.

    PubMed Central

    Tang, Guiying; Xu, Pingli; Liu, Wei; Liu, Zhanji; Shan, Lei

    2015-01-01

    LEAFY COTYLEDON1 (LEC1) is a B subunit of Nuclear Factor Y (NF-YB) transcription factor that mainly accumulates during embryo development. We cloned the 5′ flanking regulatory sequence of AhLEC1B gene, a homolog of Arabidopsis LEC1, and analyzed its regulatory elements using online software. To identify the crucial regulatory region, we generated a series of GUS expression frameworks driven by different length promoters with 5′ terminal and/or 3′ terminal deletion. We further characterized the GUS expression patterns in the transgenic Arabidopsis lines. Our results show that both the 65bp proximal promoter region and the 52bp 5′ UTR of AhLEC1B contain the key motifs required for the essential promoting activity. Moreover, AhLEC1B is preferentially expressed in the embryo and is co-regulated by binding of its upstream genes with both positive and negative corresponding cis-regulatory elements. PMID:26426444

  19. Biochemical and functional characterization of a C-type lectin (BpLec) from Bothrops pauloensis snake venom.

    PubMed

    Castanheira, Letícia Eulálio; Nunes, Débora Cristina de Oliveira; Cardoso, Thomaz Monteiro; Santos, Paula de Souza; Goulart, Luiz Ricardo; Rodrigues, Renata Santos; Richardson, Michael; Borges, Márcia Helena; Yoneyama, Kelly Aparecida Geraldo; Rodrigues, Veridiana M

    2013-03-01

    In the present work, we report the isolation and partial biochemical characterization of BpLec, a C-type lectin purified from Bothrops pauloensis venom by one chromatographic step on an affinity agarose column immobilized with d-galactose. This protein was homogeneous by SDS-PAGE under reducing and nonreducing conditions, and was shown to be a 33.6 kDa homodimer by MALDI TOF analysis. BpLec presented an isoeletric point of 5.36. Its partial sequence of 132 amino acids for each subunit, determined by Edman degradation, revealed high identity (between 86% and 95%) when aligned with sequences of other related proteins. BpLec was capable of agglutinating native dog and cat erythrocytes and this activity was inhibited by β-galactosides and EDTA. Its hemagglutinating activity was abolished at high temperatures and stable in any pH range. BpLec was effective in inhibiting Gram-positive but not Gram-negative bacteria. In addition, BpLec agglutinated promastigote forms of Leishmania (Leishmania) amazonensis. PMID:23178369

  20. CaLecRK-S.5, a pepper L-type lectin receptor kinase gene, confers broad-spectrum resistance by activating priming

    PubMed Central

    Woo, Joo Yong; Jeong, Kwang Ju; Kim, Young Jin; Paek, Kyung-Hee

    2016-01-01

    In Arabidopsis, several L-type lectin receptor kinases (LecRKs) have been identified as putative immune receptors. However, to date, there have been few analyses of LecRKs in crop plants. Virus-induced gene silencing of CaLecRK-S.5 verified the role of CaLecRK-S.5 in broad-spectrum resistance. Compared with control plants, CaLecRK-S.5-silenced plants showed reduced hypersensitive response, reactive oxygen species burst, secondary metabolite production, mitogen-activated protein kinase activation, and defense-related gene expression in response to Tobacco mosaic virus pathotype P0 (TMV-P0) infection. Suppression of CaLecRK-S.5 expression significantly enhanced the susceptibility to Pepper mild mottle virus pathotype P1,2,3, Xanthomonas campestris pv. vesicatoria, Phytophthora capsici, as well as TMV-P0. Additionally, β-aminobutyric acid treatment and a systemic acquired resistance assay revealed that CaLecRK-S.5 is involved in priming of plant immunity. Pre-treatment with β-aminobutyric acid before viral infection restored the reduced disease resistance phenotypes shown in CaLecRK-S.5-silenced plants. Systemic acquired resistance was also abolished in CaLecRK-S.5-silenced plants. Finally, RNA sequencing analysis indicated that CaLecRK-S.5 positively regulates plant immunity at the transcriptional level. Altogether, these results suggest that CaLecRK-S.5-mediated broad-spectrum resistance is associated with the regulation of priming. PMID:27647723

  1. The ALICE Pixel Detector

    NASA Astrophysics Data System (ADS)

    Mercado-Perez, Jorge

    2002-07-01

    The present document is a brief summary of the performed activities during the 2001 Summer Student Programme at CERN under the Scientific Summer at Foreign Laboratories Program organized by the Particles and Fields Division of the Mexican Physical Society (Sociedad Mexicana de Fisica). In this case, the activities were related with the ALICE Pixel Group of the EP-AIT Division, under the supervision of Jeroen van Hunen, research fellow in this group. First, I give an introduction and overview to the ALICE experiment; followed by a description of wafer probing. A brief summary of the test beam that we had from July 13th to July 25th is given as well.

  2. Recovery and recycling of limestone in LEC flue gas desulfurization. Final report, third year

    SciTech Connect

    Gardner, N.C.; Boo, J.Y.

    1993-12-20

    A potentially attractive flue gas desulfurization method called Limestone Emission Control (LEC) is currently being investigated by Prudich at Ohio University. In this process, beds of 1/8 inch limestone gravel particles absorb sulfur dioxide from flue gas. This forms sulfite and sulfate salts which coat limestone, blinding the surface and limiting utilization to 20%. Favorable economics can be generating when the unreacted portion of the limestone is recovered by mechanical grinding. This project is a wet method for grinding and recovering the spent limestone from the LEC process, utilizing an impeller fluidizer, a new type of slurry processor. It consists of a cylindrical vessel with an impeller at one end. The impeller generates sufficient pressure head to serve as a slurry pump. It combines the operation of wet grinding, washing, and transporting the spent and recovered limestone as an aqueous slurry. The objectives of the first two years were to operate fluidizer in a batch mode to carry grinding experiments, and to determine the removal of the sulfur coatings from the limestone when operating the fluidizer in a continuous mode. The main thrusts of the third year were to complete the grinding data and coordinate the data with reactivity determinations of the recovered limestone. Direct measurement of power requirements, operation of single impeller fluidizer, grinding of surface deposits and other methods of removing surface deposits have also been investigated along with sorption characteristics of recovered limestone, microscopic examination of the limestone surface, and limestone attrition.

  3. Enhanced seed oil production in canola by conditional expression of Brassica napus LEAFY COTYLEDON1 and LEC1-LIKE in developing seeds.

    PubMed

    Tan, Helin; Yang, Xiaohui; Zhang, Fengxia; Zheng, Xiu; Qu, Cunmin; Mu, Jinye; Fu, Fuyou; Li, Jiana; Guan, Rongzhan; Zhang, Hongsheng; Wang, Guodong; Zuo, Jianru

    2011-07-01

    The seed oil content in oilseed crops is a major selection trait to breeders. In Arabidopsis (Arabidopsis thaliana), LEAFY COTYLEDON1 (LEC1) and LEC1-LIKE (L1L) are key regulators of fatty acid biosynthesis. Overexpression of AtLEC1 and its orthologs in canola (Brassica napus), BnLEC1 and BnL1L, causes an increased fatty acid level in transgenic Arabidopsis plants, which, however, also show severe developmental abnormalities. Here, we use truncated napin A promoters, which retain the seed-specific expression pattern but with a reduced expression level, to drive the expression of BnLEC1 and BnL1L in transgenic canola. Conditional expression of BnLEC1 and BnL1L increases the seed oil content by 2% to 20% and has no detrimental effects on major agronomic traits. In the transgenic canola, expression of a subset of genes involved in fatty acid biosynthesis and glycolysis is up-regulated in developing seeds. Moreover, the BnLEC1 transgene enhances the expression of several genes involved in Suc synthesis and transport in developing seeds and the silique wall. Consistently, the accumulation of Suc and Fru is increased in developing seeds of the transgenic rapeseed, suggesting the increased carbon flux to fatty acid biosynthesis. These results demonstrate that BnLEC1 and BnL1L are reliable targets for genetic improvement of rapeseed in seed oil production.

  4. Inhibitory effects of trientine, a copper-chelating agent, on induction of DNA strand breaks in kidney cells of Long-Evans Cinnamon (LEC) rats.

    PubMed

    Hayashi, Masanobu; Miyane, Kazuhiro; Senou, Misato; Endoh, Daiji; Higuchi, Hidetoshi; Nagahata, Hajime; Nakayama, Kenji; Kon, Yasuhiro; Okui, Toyo

    2005-10-01

    The effects of treatment with trientine, a specific copper-chelating agent, on the accumulation of copper and induction of DNA strand breaks were investigated in Long-Evans Cinnamon (LEC) rats, an animal model for human Wilson's disease. Copper accumulated in the kidneys of LEC rats in an age-dependent manner from 12 to 18 weeks of age. When LEC rats were treated with trientine from 10 weeks of age, renal copper contents did not increase and were maintained at the same levels as those in 4-week-old LEC rats. Estimation of the amounts of DNA single-strand breaks (SSBs) by comet assay showed that SSBs of DNA were induced in a substantial population of LEC rat renal cortex cells around 12 weeks of age and that the amounts of SSBs increased in an age-dependent manner from 12 to 18 weeks of age. When LEC rats were treated with trientine from 10 weeks of age, the observed number of cells with DNA damage decreased, suggesting that induction of SSBs of DNA was inhibited and/or SSBs were repaired during the period of treatment with trientine. The results show that SSBs of DNA in LEC rat kidney cells are induced prior to occurrence of clinical signs of hepatic injury and that treatment of LEC rats with trientine decreases the number of DNA strand breaks.

  5. Imaging properties of pixellated scintillators with deep pixels

    NASA Astrophysics Data System (ADS)

    Barber, H. Bradford; Fastje, David; Lemieux, Daniel; Grim, Gary P.; Furenlid, Lars R.; Miller, Brian W.; Parkhurst, Philip; Nagarkar, Vivek V.

    2014-09-01

    We have investigated the light-transport properties of scintillator arrays with long, thin pixels (deep pixels) for use in high-energy gamma-ray imaging. We compared 10x10 pixel arrays of YSO:Ce, LYSO:Ce and BGO (1mm x 1mm x 20 mm pixels) made by Proteus, Inc. with similar 10x10 arrays of LSO:Ce and BGO (1mm x 1mm x 15mm pixels) loaned to us by Saint-Gobain. The imaging and spectroscopic behaviors of these scintillator arrays are strongly affected by the choice of a reflector used as an inter-pixel spacer (3M ESR in the case of the Proteus arrays and white, diffuse-reflector for the Saint-Gobain arrays). We have constructed a 3700-pixel LYSO:Ce Prototype NIF Gamma-Ray Imager for use in diagnosing target compression in inertial confinement fusion. This system was tested at the OMEGA Laser and exhibited significant optical, inter-pixel cross-talk that was traced to the use of a single-layer of ESR film as an inter-pixel spacer. We show how the optical cross-talk can be mapped, and discuss correction procedures. We demonstrate a 10x10 YSO:Ce array as part of an iQID (formerly BazookaSPECT) imager and discuss issues related to the internal activity of 176Lu in LSO:Ce and LYSO:Ce detectors.

  6. Pixelation Effects in Weak Lensing

    NASA Astrophysics Data System (ADS)

    High, F. William; Rhodes, Jason; Massey, Richard; Ellis, Richard

    2007-11-01

    Weak gravitational lensing can be used to investigate both dark matter and dark energy but requires accurate measurements of the shapes of faint, distant galaxies. Such measurements are hindered by the finite resolution and pixel scale of digital cameras. We investigate the optimum choice of pixel scale for a space-based mission, using the engineering model and survey strategy of the proposed Supernova Acceleration Probe as a baseline. We do this by simulating realistic astronomical images containing a known input shear signal and then attempting to recover the signal using the Rhodes, Refregier, & Groth algorithm. We find that the quality of shear measurement is always improved by smaller pixels. However, in practice, telescopes are usually limited to a finite number of pixels and operational life span, so the total area of a survey increases with pixel size. We therefore fix the survey lifetime and the number of pixels in the focal plane while varying the pixel scale, thereby effectively varying the survey size. In a pure trade-off for image resolution versus survey area, we find that measurements of the matter power spectrum would have minimum statistical error with a pixel scale of 0.09" for a 0.14" FWHM point-spread function (PSF). The pixel scale could be increased to ~0.16" if images dithered by exactly half-pixel offsets were always available. Some of our results do depend on our adopted shape measurement method and should be regarded as an upper limit: future pipelines may require smaller pixels to overcome systematic floors not yet accessible, and, in certain circumstances, measuring the shape of the PSF might be more difficult than those of galaxies. However, the relative trends in our analysis are robust, especially those of the surface density of resolved galaxies. Our approach thus provides a snapshot of potential in available technology, and a practical counterpart to analytic studies of pixelation, which necessarily assume an idealized shape

  7. Discovery of two classes of potent glycomimetic inhibitors of Pseudomonas aeruginosa LecB with distinct binding modes.

    PubMed

    Hauck, Dirk; Joachim, Ines; Frommeyer, Benjamin; Varrot, Annabelle; Philipp, Bodo; Möller, Heiko M; Imberty, Anne; Exner, Thomas E; Titz, Alexander

    2013-08-16

    The treatment of infections due to the opportunistic pathogen Pseudomonas aeruginosa is often difficult, as a consequence of bacterial biofilm formation. Such a protective environment shields the bacterium from host defense and antibiotic treatment and secures its survival. One crucial factor for maintenance of the biofilm architecture is the carbohydrate-binding lectin LecB. Here, we report the identification of potent mannose-based LecB inhibitors from a screening of four series of mannosides in a novel competitive binding assay for LecB. Cinnamide and sulfonamide derivatives are inhibitors of bacterial adhesion with up to a 20-fold increase in affinity to LecB compared to the natural ligand methyl mannoside. Because many lectins of the host require terminal saccharides (e.g., fucosides), such capped structures as reported here may offer a beneficial selectivity profile for the pathogenic lectin. Both classes of compounds show distinct binding modes at the protein, offering the advantage of a simultaneous development of two new lead structures as anti-pseudomonadal drugs with an anti-virulence mode of action.

  8. Deep levels in semi-insulating LEC GaAs before and after silicon implantation

    SciTech Connect

    Dindo, S.; Abdel-Motaleb, I.; Lowe, K.; Tang, W.; Young, L.

    1985-11-01

    The deep trapping levels present before ion implantation of silicon into the semi-insulating LEC GaAs starting material were investigated using optical transient current spectroscopy (OTCS). MESFET channel current deep level transient spectroscopy (DLTS) was used for the implanted material. With a silicon nitride layer used t encapsulate the GaAs for postimplantation annealing and with implantation directly into the GaAs, it was found tha of seven or more deep levels seen in the semi-insulating substrate prior to silicon implantation only the level believed to be EL12 remained. On implanting through a thin Si/sub 3/N/sub 4/ encapsulating layer and annealing under Si/sub 3/N/sub 4/, only EL2 was found. With a silicon dioxide layer as an encapsulant, two traps remained and two apparently unreported levels appeared.

  9. Performance of Jay/LEC fields unit under mature waterflood and early tertiary operations

    SciTech Connect

    Langston, E.P.; Shirer, J.A.

    1985-02-01

    Secondary oil recovery for the Jay/Little Escambia Creek (LEC) Fields Unit will exceed initial estimates by 27 X 10/sup 6/ bbl (4.3 X 10/sup 6/ m/sup 3/) because of innovative reservoir management based on a comprehensive surveillance program and detailed reservoir description data. Infill drill wells have accounted for 76 X 10/sup 6/ bbl (12 X 10/sup 6/ m/sup 3/) of oil production. The mature waterflood was phased into a tertiary recovery project in 1981, and early performance is generally consistent with the planning study, which predicted that 47 X 10/sup 6/ bbl (7.5 X 10/sup 6/ m/sup 3/) of tertiary oil will be recovered.

  10. A comparative study of heavily irradiated silicon and non irradiated SI LEC GaAs detectors

    SciTech Connect

    Biggeri, U.; Borchi, E.; Bruzzi, M.

    1998-06-01

    Silicon p{sup +}n junctions irradiated with neutron and proton fluences in the range 5 {times} 10{sup 11}--4 {times} 10{sup 15} cm{sup {minus}2} and non-irradiated Semi Insulating (SI) LEC GaAs Schottky barriers have been analyzed. In silicon the concentration N{sub t} of the main radiation-induced deep traps (Et {approx} 0.44--0.54 eV) is found to increase as N{sub t} {alpha} f achieving values up to 5 {times} 10{sup 15} cm{sup {minus}3} and a mobility saturation at 100 cm{sup 2}/Vs has been observed at the highest fluences. A quantitative comparison between heavily irradiated silicon and non-irradiated GaAs evidenced similar charge collection efficiencies, a quasi-intrinsic bulk and similar concentrations of deep defects. On this basis, a unique model, correlating the lattice disorder and the detector performance, is suggested.

  11. THE KEPLER PIXEL RESPONSE FUNCTION

    SciTech Connect

    Bryson, Stephen T.; Haas, Michael R.; Dotson, Jessie L.; Koch, David G.; Borucki, William J.; Tenenbaum, Peter; Jenkins, Jon M.; Chandrasekaran, Hema; Caldwell, Douglas A.; Klaus, Todd; Gilliland, Ronald L.

    2010-04-20

    Kepler seeks to detect sequences of transits of Earth-size exoplanets orbiting solar-like stars. Such transit signals are on the order of 100 ppm. The high photometric precision demanded by Kepler requires detailed knowledge of how the Kepler pixels respond to starlight during a nominal observation. This information is provided by the Kepler pixel response function (PRF), defined as the composite of Kepler's optical point-spread function, integrated spacecraft pointing jitter during a nominal cadence and other systematic effects. To provide sub-pixel resolution, the PRF is represented as a piecewise-continuous polynomial on a sub-pixel mesh. This continuous representation allows the prediction of a star's flux value on any pixel given the star's pixel position. The advantages and difficulties of this polynomial representation are discussed, including characterization of spatial variation in the PRF and the smoothing of discontinuities between sub-pixel polynomial patches. On-orbit super-resolution measurements of the PRF across the Kepler field of view are described. Two uses of the PRF are presented: the selection of pixels for each star that maximizes the photometric signal-to-noise ratio for that star, and PRF-fitted centroids which provide robust and accurate stellar positions on the CCD, primarily used for attitude and plate scale tracking. Good knowledge of the PRF has been a critical component for the successful collection of high-precision photometry by Kepler.

  12. Uncooled microbolometer detector: recent development at Ulis

    NASA Astrophysics Data System (ADS)

    Tissot, J. L.; Trouilleau, C.; Crastes, A.; Fièque, B.; Legras, O.

    2005-10-01

    Uncooled infrared focal plane arrays are being developed for a wide range of thermal imaging applications. Firefighting, predictive maintenance, process control and thermography are a few of the industrial applications which could take benefit from uncooled infrared detector. Therefore, to answer these markets, a 35 μm pixel-pitch uncooled IR detector technology has been developed enabling high performance 160 x 120 and 384 x 288 arrays production. Besides a wide-band version from uncooled 320 x 240 / 45 μm array has been also developed in order to address process control and more precisely industrial furnaces control. The ULIS amorphous silicon technology is well adapted to manufacture low cost detector in mass production. After some brief microbolometer technological background, we present the characterization of 35 μm pixel-pitch detector as well as the wide-band 320 x 240 infrared focal plane arrays with a pixel pitch of 45 μm.

  13. Uncooled microbolometer detector: recent developments at ULIS

    NASA Astrophysics Data System (ADS)

    Tissot, J. L.; Legras, O.; Trouilleau, C.; Crastes, A.; Fièque, B.

    2005-10-01

    Uncooled infrared focal plane arrays are being developed for a wide range of thermal imaging applications. Firefighting, predictive maintenance, process control and thermography are a few of the industrial applications which could take benefit from uncooled infrared detector. Therefore, to answer these markets, a 35 μm pixel-pitch uncooled IR detector technology has been developed enabling high performance 160 x 120 and 384 x 288 arrays production. Besides a wide-band version from uncooled 320 x 240 / 45 μm array has been also developed in order to address process control and more precisely industrial furnaces control. The ULIS amorphous silicon technology is well adapted to manufacture low cost detector in mass production. After some brief microbolometer technological background, we present the characterization of 35 μm pixel-pitch detector as well as the wide-band 320 x 240 infrared focal plane arrays with a pixel pitch of 45 μm.

  14. Uncooled microbolometer detector: recent developments at Ulis

    NASA Astrophysics Data System (ADS)

    Tissot, J. L.; Trouilleau, C.; Fieque, B.; Crastes, A.; Legras, O.

    2005-09-01

    Uncooled infrared focal plane arrays are being developed for a wide range of thermal imaging applications. Fire-fighting, predictive maintenance, process control and thermography are a few of the industrial applications which could take benefit from uncooled infrared detector. Therefore, to answer these markets, a 35 μm pixel-pitch uncooled IR detector technology has been developed enabling high performance 160 x 120 and 384 x 288 arrays production. Besides a wide-band version from uncooled 320 x 240 / 45 μm array has been also developed in order to address process control and more precisely industrial furnaces control. The ULIS amorphous silicon technology is well adapted to manufacture low cost detector in mass production. After some brief microbolometer technological background, we present the characterization of 35 μm pixel-pitch detector as well as the wide-band 320 x 240 infrared focal plane arrays with a pixel pitch of 45 μm.

  15. The Arabidopsis LecRK-VI.2 associates with the pattern-recognition receptor FLS2 and primes Nicotiana benthamiana pattern-triggered immunity.

    PubMed

    Huang, Pin-Yao; Yeh, Yu-Hung; Liu, An-Chi; Cheng, Chiu-Ping; Zimmerli, Laurent

    2014-07-01

    Pattern-triggered immunity (PTI) is broad spectrum and manipulation of PTI is believed to represent an attractive way to engineer plants with broad-spectrum disease resistance. PTI is activated upon perception of microbe-associated molecular patterns (MAMPs) by pattern-recognition receptors (PRRs). We have recently demonstrated that the L-type lectin receptor kinase-VI.2 (LecRK-VI.2) positively regulates Arabidopsis thaliana PTI. Here we show through in vitro pull-down, bimolecular fluorescence complementation and co-immunoprecipitation analyses that LecRK-VI.2 associates with the PRR FLS2. We also demonstrated that LecRK-VI.2 from the cruciferous plant Arabidopsis remains functional after interfamily transfer to the Solanaceous plant Nicotiana benthamiana. Wild tobacco plants ectopically expressing LecRK-VI.2 were indeed more resistant to virulent hemi-biotrophic and necrotrophic bacteria, but not to the fungal pathogen Botrytis cinerea suggesting that, as with Arabidopsis, the LecRK-VI.2 protective effect in N. benthamiana is bacteria specific. Ectopic expression of LecRK-VI.2 in N. benthamiana primed PTI-mediated reactive oxygen species production, mitogen-activated protein kinase (MAPK) activity, callose deposition and gene expression upon treatment with the MAMP flagellin. Our findings identified LecRK-VI.2 as a member of the FLS2 receptor complex and suggest that heterologous expression of components of PRR complexes can be used as tools to engineer plant disease resistance to bacteria.

  16. MytiLec, a Mussel R-Type Lectin, Interacts with Surface Glycan Gb3 on Burkitt’s Lymphoma Cells to Trigger Apoptosis through Multiple Pathways

    PubMed Central

    Hasan, Imtiaj; Sugawara, Shigeki; Fujii, Yuki; Koide, Yasuhiro; Terada, Daiki; Iimura, Naoya; Fujiwara, Toshiyuki; Takahashi, Keisuke G.; Kojima, Nobuhiko; Rajia, Sultana; Kawsar, Sarkar M. A.; Kanaly, Robert A.; Uchiyama, Hideho; Hosono, Masahiro; Ogawa, Yukiko; Fujita, Hideaki; Hamako, Jiharu; Matsui, Taei; Ozeki, Yasuhiro

    2015-01-01

    MytiLec; a novel lectin isolated from the Mediterranean mussel (Mytilus galloprovincialis); shows strong binding affinity to globotriose (Gb3: Galα1-4Galβ1-4Glc). MytiLec revealed β-trefoil folding as also found in the ricin B-subunit type (R-type) lectin family, although the amino acid sequences were quite different. Classification of R-type lectin family members therefore needs to be based on conformation as well as on primary structure. MytiLec specifically killed Burkitt's lymphoma Ramos cells, which express Gb3. Fluorescein-labeling assay revealed that MytiLec was incorporated inside the cells. MytiLec treatment of Ramos cells resulted in activation of both classical MAPK/ extracellular signal-regulated kinase and extracellular signal-regulated kinase (MEK-ERK) and stress-activated (p38 kinase and JNK) Mitogen-activated protein kinases (MAPK) pathways. In the cells, MytiLec treatment triggered expression of tumor necrosis factor (TNF)-α (a ligand of death receptor-dependent apoptosis) and activation of mitochondria-controlling caspase-9 (initiator caspase) and caspase-3 (activator caspase). Experiments using the specific MEK inhibitor U0126 showed that MytiLec-induced phosphorylation of the MEK-ERK pathway up-regulated expression of the cyclin-dependent kinase inhibitor p21, leading to cell cycle arrest and TNF-α production. Activation of caspase-3 by MytiLec appeared to be regulated by multiple different pathways. Our findings, taken together, indicate that the novel R-type lectin MytiLec initiates programmed cell death of Burkitt’s lymphoma cells through multiple pathways (MAPK cascade, death receptor signaling; caspase activation) based on interaction of the lectin with Gb3-containing glycosphingolipid-enriched microdomains on the cell surface. PMID:26694420

  17. cDNA and Gene Structure of MytiLec-1, A Bacteriostatic R-Type Lectin from the Mediterranean Mussel (Mytilus galloprovincialis).

    PubMed

    Hasan, Imtiaj; Gerdol, Marco; Fujii, Yuki; Rajia, Sultana; Koide, Yasuhiro; Yamamoto, Daiki; Kawsar, Sarkar M A; Ozeki, Yasuhiro

    2016-01-01

    MytiLec is an α-d-galactose-binding lectin with a unique primary structure isolated from the Mediterranean mussel (Mytilus galloprovincialis). The lectin adopts a β-trefoil fold that is also found in the B-sub-unit of ricin and other ricin-type (R-type) lectins. We are introducing MytiLec(-1) and its two variants (MytiLec-2 and -3), which both possess an additional pore-forming aerolysin-like domain, as members of a novel multi-genic "mytilectin family" in bivalve mollusks. Based on the full length mRNA sequence (911 bps), it was possible to elucidate the coding sequence of MytiLec-1, which displays an extended open reading frame (ORF) at the 5' end of the sequence, confirmed both at the mRNA and at the genomic DNA sequence level. While this extension could potentially produce a polypeptide significantly longer than previously reported, this has not been confirmed yet at the protein level. MytiLec-1 was revealed to be encoded by a gene consisting of two exons and a single intron. The first exon comprised the 5'UTR and the initial ATG codon and it was possible to detect a putative promoter region immediately ahead of the transcription start site in the MytiLec-1 genomic locus. The remaining part of the MytiLec-1 coding sequence (including the three sub-domains, the 3'UTR and the poly-A signal) was included in the second exon. The bacteriostatic activity of MytiLec-1 was determined by the agglutination of both Gram-positive and Gram-negative bacteria, which was reversed by the co-presence of α-galactoside. Altogether, these data support the classification of MytiLec-1 as a member of the novel mytilectin family and suggest that this lectin may play an important role as a pattern recognition receptor in the innate immunity of mussels.

  18. From Pixels to Planets

    NASA Technical Reports Server (NTRS)

    Brownston, Lee; Jenkins, Jon M.

    2015-01-01

    The Kepler Mission was launched in 2009 as NASAs first mission capable of finding Earth-size planets in the habitable zone of Sun-like stars. Its telescope consists of a 1.5-m primary mirror and a 0.95-m aperture. The 42 charge-coupled devices in its focal plane are read out every half hour, compressed, and then downlinked monthly. After four years, the second of four reaction wheels failed, ending the original mission. Back on earth, the Science Operations Center developed the Science Pipeline to analyze about 200,000 target stars in Keplers field of view, looking for evidence of periodic dimming suggesting that one or more planets had crossed the face of its host star. The Pipeline comprises several steps, from pixel-level calibration, through noise and artifact removal, to detection of transit-like signals and the construction of a suite of diagnostic tests to guard against false positives. The Kepler Science Pipeline consists of a pipeline infrastructure written in the Java programming language, which marshals data input to and output from MATLAB applications that are executed as external processes. The pipeline modules, which underwent continuous development and refinement even after data started arriving, employ several analytic techniques, many developed for the Kepler Project. Because of the large number of targets, the large amount of data per target and the complexity of the pipeline algorithms, the processing demands are daunting. Some pipeline modules require days to weeks to process all of their targets, even when run on NASA's 128-node Pleiades supercomputer. The software developers are still seeking ways to increase the throughput. To date, the Kepler project has discovered more than 4000 planetary candidates, of which more than 1000 have been independently confirmed or validated to be exoplanets. Funding for this mission is provided by NASAs Science Mission Directorate.

  19. Toward the Rational Design of Galactosylated Glycoclusters That Target Pseudomonas aeruginosa Lectin A (LecA): Influence of Linker Arms That Lead to Low-Nanomolar Multivalent Ligands.

    PubMed

    Wang, Shuai; Dupin, Lucie; Noël, Mathieu; Carroux, Cindy J; Renaud, Louis; Géhin, Thomas; Meyer, Albert; Souteyrand, Eliane; Vasseur, Jean-Jacques; Vergoten, Gérard; Chevolot, Yann; Morvan, François; Vidal, Sébastien

    2016-08-01

    Anti-infectious strategies against pathogen infections can be achieved through antiadhesive strategies by using multivalent ligands of bacterial virulence factors. LecA and LecB are lectins of Pseudomonas aeruginosa implicated in biofilm formation. A series of 27 LecA-targeting glycoclusters have been synthesized. Nine aromatic galactose aglycons were investigated with three different linker arms that connect the central mannopyranoside core. A low-nanomolar (Kd =19 nm, microarray) ligand with a tyrosine-based linker arm could be identified in a structure-activity relationship study. Molecular modeling of the glycoclusters bound to the lectin tetramer was also used to rationalize the binding properties observed.

  20. CMS Pixel Data Quality Monitoring

    NASA Astrophysics Data System (ADS)

    Merkel, Petra

    2010-05-01

    We present the CMS Pixel Data Quality Monitoring (DQM) system. The concept and architecture are discussed. The monitored quantities are introduced, and the methods on how to ensure that the detector takes high-quality data with large efficiency are explained. Finally we describe the automated data certification scheme, which is used to certify and classify the data from the Pixel detector for physics analyses.

  1. Local Pixel Bundles: Bringing the Pixels to the People

    NASA Astrophysics Data System (ADS)

    Anderson, Jay

    2014-12-01

    The automated galaxy-based alignment software package developed for the Frontier Fields program (hst2galign, see Anderson & Ogaz 2014 and http://www.stsci.edu/hst/campaigns/frontier-fields/) produces a direct mapping from the pixels of the flt frame of each science exposure into a common master frame. We can use these mappings to extract the flt-pixels in the vicinity of a source of interest and package them into a convenient "bundle". In addition to the pixels, this data bundle can also contain "meta" information that will allow users to transform positions from the flt pixels to the reference frame and vice-versa. Since the un-resampled pixels in the flt frames are the only true constraints we have on the astronomical scene, the ability to inter-relate these pixels will enable many high-precision studies, such as: point-source-fitting and deconvolution with accurate PSFs, easy exploration of different image-combining algorithms, and accurate faint-source finding and photometry. The data products introduced in this ISR are a very early attempt to provide the flt-level pixel constraints in a package that is accessible to more than the handful of experts in HST astrometry. The hope is that users in the community might begin using them and will provide feedback as to what information they might want to see in the bundles and what general analysis packages they might find useful. For that reason, this document is somewhat informally written, since I know that it will be modified and updated as the products and tools are optimized.

  2. Recovery and recycling of limestone in LEC flue gas desulfurization. Final report, June 1, 1990--August 31, 1991

    SciTech Connect

    Gardner, N.C.; Adler, R.J.; Lin, Y.C.; Unger, M.E.; Lux, K.W.

    1992-03-01

    Prudich et al. have proposed an attractive technology called Limestone Emission Control (LEC) for removing sulfur dioxide from flue gases. Beds of 1/8 inch wet limestone particles absorb the sulfur dioxide from the gases. Sulfates and sulfites deposit on the surfaces of the particles, limiting their utilization to about 20%. The unreacted portion of the limestone can be recovered by mechanical grinding and recycling, enabling high overall sorbent utilization. Favorable economic costs derive from small equipment, simplicity, and low sorbent cost. Our research concentrates on selecting and testing on a laboratory scale suitable candidate dry and wet grinding methods for recovering limestone in LEC flue from desulfurization. A wet grinding method based on the impeller fluidizer, a new type of slurry processor, receives special attention. The impeller fluidizer is a dosed cylindrical vessel with an impeller at one end. It combines the operations of wet grinding, washing, and transporting the spent and recovered limestone as an aqueous slurry.

  3. Pilot-scale Limestone Emission Control (LEC) process: A development project. Volume 1, Main report and appendices A, B, C, and D: Final report

    SciTech Connect

    Prudich, M.E.; Appell, K.W.; McKenna, J.D.

    1994-03-01

    ETS, Inc., a pollution consulting firm with headquarters in Roanoke, Virginia, has developed a dry, limestone-based flue gas desulfurization (FGD) system. This SO{sub 2} removal system, called Limestone Emission Control (LEC), can be designed for installation on either new or existing coal-fired boilers. In the LEC process, the SO{sub 2} in the flue gas reacts with wetted granular limestone that is contained in a moving bed. A surface layer of principally calcium sulfate (CaSO{sub 4}) is formed on the limestone. Periodic removal of this surface layer by mechanical agitation allows high utilization of the limestone granules. A nominal 5,000 acfm LEC pilot plant has been designed, fabricated and installed on the slipstream of a 70,000 pph stoker boiler providing steam to Ohio University`s Athens, Ohio campus. A total of over 90 experimental trials have been performed using the pilot-scale moving-bed LEC dry scrubber as a part of this research project with run times ranging up to a high of 125 hours. SO{sub 2} removal efficiencies as high as 99.9% were achievable for all experimental conditions studied during which sufficient humidification was added to the LEC bed. The LEC process and conventional limestone scrubbing have been compared on an equatable basis using flue gas conditions that would be expected at the outlet of the electrostatic precipitator (ESP) of a 500 MW coal-fired power plant. The LEC was found to have a definite economic advantage in both direct capital costs and operating costs. Based on the success and findings of the present project, the next step in LEC process development will be a full-scale commercial demonstration unit.

  4. Synthesis of mannoheptose derivatives and their evaluation as inhibitors of the lectin LecB from the opportunistic pathogen Pseudomonas aeruginosa.

    PubMed

    Hofmann, Anna; Sommer, Roman; Hauck, Dirk; Stifel, Julia; Göttker-Schnetmann, Inigo; Titz, Alexander

    2015-08-14

    Biofilm formation and chronic infections with Pseudomonas aeruginosa depend on lectins produced by the bacterium. The bacterial C-type lectin LecB binds to the two monosaccharides l-fucose and d-mannose and conjugates thereof. Previously, d-mannose derivatives with amide and sulfonamide substituents at C6 were reported as potent inhibitors of the bacterial lectin LecB and LecB-mediated bacterial surface adhesion. Because d-mannose establishes a hydrogen bond via its 6-OH group with Ser23 of LecB in the crystal structure and may be beneficial for binding affinity, we extended d-mannose and synthesized mannoheptoses bearing the free 6-OH group as well as amido and sulfonamido-substituents at C7. Two series of diastereomeric mannoheptoses were synthesized and the stereochemistry was determined by X-ray crystallography. The potency of the mannoheptoses as LecB inhibitors was assessed in a competitive binding assay. The data reveal a diastereoselectivity of LecB for (6S)-mannoheptose derivatives with increased activity over methyl α-d-mannoside.

  5. Role of p38 Mapk in development of acute hepatic injury in Long-Evans Cinnamon (LEC) rats, an animal model of human Wilson's disease.

    PubMed

    Kadowaki, Shingo; Meguro, Saori; Imaizumi, Yoshitaka; Sakai, Hiroshi; Endoh, Daiji; Hayashi, Masanobu

    2013-12-30

    The Long-Evans Cinnamon (LEC) rat, an animal model of human Wilson's disease, spontaneously develops fulminant hepatitis associated with severe jaundice at about 4 months of age. In this study, we examined the changes in gene expression during progression of acute hepatic injury. When levels of gene expression in the liver of LEC rats at 13 weeks of age were compared to those in rats at 4 weeks of age using oligonucleotide arrays, 1,620 genes out of 7,700 genes analyzed showed more than 2-fold differences. Expression levels of 11 of 29 genes related to stress-activating protein kinase (SAPK) changed by more than 2-fold in the liver of LEC rats, but none of the SAPK-related genes showed changes in expression levels in the liver of control rats. Activity of p38 mapk in the liver of LEC rats at 13 weeks of age was about 8.1-fold higher than that in rats at 4 weeks of age. When LEC rats were administered SB203580, a p38 mapk-specific inhibitor, by s.c. injection twice a week from 10 to 13 weeks of age, activities of p38 mapk in the liver, activities of AST and ALT and concentrations of bilirubin in sera of rats administered SB203580 significantly decreased compared to those in rats not administered. These results showed that the increase in activities of p38 mapk was related to the occurrence of acute hepatic injury in LEC rats.

  6. Cucumis sativus L-type lectin receptor kinase (CsLecRK) gene family response to Phytophthora melonis, Phytophthora capsici and water immersion in disease resistant and susceptible cucumber cultivars.

    PubMed

    Wu, Tingquan; Wang, Rui; Xu, Xiaomei; He, Xiaoming; Sun, Baojuan; Zhong, Yujuan; Liang, Zhaojuan; Luo, Shaobo; Lin, Yu'e

    2014-10-10

    L-type lectin receptor kinase (LecRK) proteins are an important family involved in diverse biological processes such as pollen development, senescence, wounding, salinity and especially in innate immunity in model plants such as Arabidopsis and tobacco. Till date, LecRK proteins or genes of cucumber have not been reported. In this study, a total of 25 LecRK genes were identified in the cucumber genome, unequally distributed across its seven chromosomes. According to similarity comparison of their encoded proteins, the Cucumis sativus LecRK (CsLecRK) genes were classified into six major clades (from Clade I to CladeVI). Expression of CsLecRK genes were tested using QRT-PCR method and the results showed that 25 CsLecRK genes exhibited different responses to abiotic (water immersion) and biotic (Phytophthora melonis and Phytophthora capsici inoculation) stresses, as well as that between disease resistant cultivar (JSH) and disease susceptible cultivar (B80). Among the 25 CsLecRK genes, we found CsLecRK6.1 was especially induced by P. melonis and P. capsici in JSH plants. All these results suggested that CsLecRK genes may play important roles in biotic and abiotic stresses.

  7. Cinnamide Derivatives of d‐Mannose as Inhibitors of the Bacterial Virulence Factor LecB from Pseudomonas aeruginosa †

    PubMed Central

    Sommer, Roman; Hauck, Dirk; Varrot, Annabelle; Wagner, Stefanie; Audfray, Aymeric; Prestel, Andreas; Möller, Heiko M.; Imberty, Anne

    2015-01-01

    Abstract Pseudomonas aeruginosa is an opportunistic Gram‐negative pathogen with high antibiotic resistance. Its lectin LecB was identified as a virulence factor and is relevant in bacterial adhesion and biofilm formation. Inhibition of LecB with carbohydrate‐based ligands results in a decrease in toxicity and biofilm formation. We recently discovered two classes of potent drug‐like glycomimetic inhibitors, that is, sulfonamides and cinnamides of d‐mannose. Here, we describe the chemical synthesis and biochemical evaluation of more than 20 derivatives with increased potency compared to the unsubstituted cinnamide. The structure–activity relationship (SAR) obtained and the extended biophysical characterization allowed the experimental determination of the binding mode of these cinnamides with LecB. The established surface binding mode now allows future rational structure‐based drug design. Importantly, all glycomimetics tested showed extended receptor residence times with half‐lives in the 5–20 min range, a prerequisite for therapeutic application. Thus, the glycomimetics described here provide an excellent basis for future development of anti‐infectives against this multidrug‐resistant pathogen. PMID:27308201

  8. Expression of ZmLEC1 and ZmWRI1 increases seed oil production in maize.

    PubMed

    Shen, Bo; Allen, William B; Zheng, Peizhong; Li, Changjiang; Glassman, Kimberly; Ranch, Jerry; Nubel, Douglas; Tarczynski, Mitchell C

    2010-07-01

    Increasing seed oil production is a major goal for global agriculture to meet the strong demand for oil consumption by humans and for biodiesel production. Previous studies to increase oil synthesis in plants have focused mainly on manipulation of oil pathway genes. As an alternative to single-enzyme approaches, transcription factors provide an attractive solution for altering complex traits, with the caveat that transcription factors may face the challenge of undesirable pleiotropic effects. Here, we report that overexpression of maize (Zea mays) LEAFY COTYLEDON1 (ZmLEC1) increases seed oil by as much as 48% but reduces seed germination and leaf growth in maize. To uncouple oil increase from the undesirable agronomic traits, we identified a LEC1 downstream transcription factor, maize WRINKLED1 (ZmWRI1). Overexpression of ZmWRI1 results in an oil increase similar to overexpression of ZmLEC1 without affecting germination, seedling growth, or grain yield. These results emphasize the importance of field testing for developing a commercial high-oil product and highlight ZmWRI1 as a promising target for increasing oil production in crops.

  9. Twinning and impurity segregation in Cr- and Fe-doped LEC InP

    NASA Astrophysics Data System (ADS)

    Holt, D. B.; Salviati, G.

    1990-03-01

    Slices of Cr- and Fe-doped LEC crystals of InP were studied by secondary electron (SE) and transmission cathodoluminescence (TCL) scanning electron microscopy. Growth striations, twins and, in the Cr-doped material, centres showing strong dot and halo contrast were seen. The twin boundaries were visible in TCL micrographs due to weak dot-and-halo (DAH) contrast at twinning dislocations so incoherent boundaries gave strong contrast and coherent twin interfaces gave contrast only at steps. The strong DAH contrast centres in InP: Cr had crystallographic forms in secondary electron SEM pictures and X-ray microanalysis showed high concentrations of Cr to be present. Weaker DAH contrast occurs at the (partial) twinning dislocations. Annealing InP: Cr at 500°C for 30 min did not produce any distinct change in the microstructure. There appeared to be two types of twin interface. Across most there was strong secondary electron channeling contrast but not across the few of the other type. Both types could be seen in TCL due to bright contrast at the dislocations along the boundary. Only weak, bright contrast was observed at twinning dislocations in InP: Fe and the absence of the gross DAH contrast centres makes it possible to study the TCL contrast properties of twins, twin interfaces and striations, which were obscured in InP: Cr.

  10. Interactions between Zn and Cu in LEC rats, an animal model of Wilson's disease.

    PubMed

    Santon, Alessandro; Giannetto, Sabrina; Sturniolo, Giacomo Carlo; Medici, Valentina; D'Incà, Renata; Irato, Paola; Albergoni, Vincenzo

    2002-03-01

    The effect of oral Zn treatment was studied in the liver and kidneys of 26 male Long-Evans Cinnamon (LEC) rats (mutant animals, 5 weeks old) in relation to both the interaction between Zn and Cu and the localisation and concentration of metallothionein (MT). Rats receiving 80 mg zinc acetate daily by gavage and control rats receiving no treatment were killed after 1 or 2 weeks. By immunohistochemical and analytical chemical techniques we revealed that treated rats had higher levels of MT in the hepatic and renal cells compared to untreated ones. Tissue Zn concentrations were significantly higher in treated rats compared to untreated whereas Cu concentrations decreased in the liver and kidneys as indicated by analytical chemical analyses. MT levels also decreased with treatment period. A histochemical procedure, obtained using autofluorescence of Cu-metallothioneins, confirms these findings: after 2 weeks, the signal decreased in both the liver and kidney sections. This gives a greater understanding of the mechanism of Cu metabolism in the two tissues considered. These results suggest that Zn acts both to compete for absorption on the luminal side of the intestinal epithelium and to induce the synthesis of MT.

  11. The CMS pixel luminosity telescope

    NASA Astrophysics Data System (ADS)

    Kornmayer, A.

    2016-07-01

    The Pixel Luminosity Telescope (PLT) is a new complement to the CMS detector for the LHC Run II data taking period. It consists of eight 3-layer telescopes based on silicon pixel detectors that are placed around the beam pipe on each end of CMS viewing the interaction point at small angle. A fast 3-fold coincidence of the pixel planes in each telescope will provide a bunch-by-bunch measurement of the luminosity. Particle tracking allows collision products to be distinguished from beam background, provides a self-alignment of the detectors, and a continuous in-time monitoring of the efficiency of each telescope plane. The PLT is an independent luminometer, essential to enhance the robustness on the measurement of the delivered luminosity and to reduce its systematic uncertainties. This will allow to determine production cross-sections, and hence couplings, with high precision and to set more stringent limits on new particle production.

  12. Stellar photometry with big pixels

    SciTech Connect

    Buonanno, R.; Iannicola, G.; European Southern Observatory, Garching )

    1989-03-01

    A new software for stellar photometry in crowded fields is presented. This software overcomes the limitations present in a traditional package like ROMAFOT when the pixel size of the detector is comparable to the scale length of point images. This is the case, for instance, with the Hubble Space Telescope-Wide Field Camera and, partially, with the Planetary Camera. The numerical solution presented here is compared to the technical solution of obtaining more exposures of the same field, each shifted by a fraction of pixel. This software will be available in MIDAS. 11 refs.

  13. Characterization of Multisugar-Binding C-Type Lectin (SpliLec) from a Bacterial-Challenged Cotton Leafworm, Spodoptera littoralis

    PubMed Central

    Seufi, AlaaEddeen M.; Galal, Fatma H.; Hafez, Elsayed E.

    2012-01-01

    Background Various proteins that display carbohydrate-binding activity in a Ca2+-dependent manner are classified into the C-type lectin family. They have one or two C-type carbohydrate-recognition domains (CRDs) composed of 110–130 amino acid residues in common. C-type lectins mediate cell adhesion, non-self recognition, and immuno-protection processes in immune responses and thus play significant roles in clearance of invaders, either as cell surface receptors for microbial carbohydrates or as soluble proteins existing in tissue fluids. The lectin of Spodoptera littoralis is still uncharacterized. Methodology A single orf encoding a deduced polypeptide consisting of an 18-residue signal peptide and a 291-residue mature peptide, termed SpliLec, was isolated from the haemolymph of the cotton leafworm, S. littoralis, after bacterial challenge using RACE-PCR. Sequence analyses of the data revealed that SpliLec consists of two CRDs. Short-form CRD1 and long-form CRD2 are stabilized by two and three highly conserved disulfide bonds, respectively. SpliLec shares homology with some dipteran lectins suggesting possible common ancestor. The purified SpliLec exhibited a 140-kDa molecular mass with a subunit molecular mass of 35 kDa. The hemagglutination assays of the SpliLec confirmed a thermally stable, multisugar-binding C-type lectin that binds different erythrocytes. The purified SpliLec agglutinated microorganisms and exhibited comparable antimicrobial activity against gram (+) and gram (−) bacteria too. Conclusions Our results suggested an important role of the SpliLec gene in cell adhesion and non-self recognition. It may cooperate with other AMPs in clearance of invaders of Spodoptera littoralis. PMID:22916161

  14. Advances in uncooled technology at BAE SYSTEMS

    NASA Astrophysics Data System (ADS)

    Backer, Brian S.; Kohin, Margaret; Leary, Arthur R.; Blackwell, Richard J.; Rumbaugh, Roy N.

    2003-09-01

    BAE SYSTEMS has made tremendous progress in uncooled technology and systems in the last year. In this paper we present performance results and imagery from our latest 640x480 and 320x240 small pixel focal plane arrays. Both were produced using submicron lithography and have achieved our lowest NETDs to date. Testing of the 320x240 devices has shown TNETDs of 30mK at F/1. Video imagery from our 640 x 480 uncooled camera installed in a POINTER Unattended Aerial Vehicle is also shown. In addition, we introduce our newest commercial imaging camera core, the SCC500 and show its vastly improved characteristics. Lastly, plans for future advancements are outlined.

  15. cDNA and Gene Structure of MytiLec-1, A Bacteriostatic R-Type Lectin from the Mediterranean Mussel (Mytilus galloprovincialis).

    PubMed

    Hasan, Imtiaj; Gerdol, Marco; Fujii, Yuki; Rajia, Sultana; Koide, Yasuhiro; Yamamoto, Daiki; Kawsar, Sarkar M A; Ozeki, Yasuhiro

    2016-01-01

    MytiLec is an α-d-galactose-binding lectin with a unique primary structure isolated from the Mediterranean mussel (Mytilus galloprovincialis). The lectin adopts a β-trefoil fold that is also found in the B-sub-unit of ricin and other ricin-type (R-type) lectins. We are introducing MytiLec(-1) and its two variants (MytiLec-2 and -3), which both possess an additional pore-forming aerolysin-like domain, as members of a novel multi-genic "mytilectin family" in bivalve mollusks. Based on the full length mRNA sequence (911 bps), it was possible to elucidate the coding sequence of MytiLec-1, which displays an extended open reading frame (ORF) at the 5' end of the sequence, confirmed both at the mRNA and at the genomic DNA sequence level. While this extension could potentially produce a polypeptide significantly longer than previously reported, this has not been confirmed yet at the protein level. MytiLec-1 was revealed to be encoded by a gene consisting of two exons and a single intron. The first exon comprised the 5'UTR and the initial ATG codon and it was possible to detect a putative promoter region immediately ahead of the transcription start site in the MytiLec-1 genomic locus. The remaining part of the MytiLec-1 coding sequence (including the three sub-domains, the 3'UTR and the poly-A signal) was included in the second exon. The bacteriostatic activity of MytiLec-1 was determined by the agglutination of both Gram-positive and Gram-negative bacteria, which was reversed by the co-presence of α-galactoside. Altogether, these data support the classification of MytiLec-1 as a member of the novel mytilectin family and suggest that this lectin may play an important role as a pattern recognition receptor in the innate immunity of mussels. PMID:27187419

  16. cDNA and Gene Structure of MytiLec-1, A Bacteriostatic R-Type Lectin from the Mediterranean Mussel (Mytilus galloprovincialis)

    PubMed Central

    Hasan, Imtiaj; Gerdol, Marco; Fujii, Yuki; Rajia, Sultana; Koide, Yasuhiro; Yamamoto, Daiki; Kawsar, Sarkar M. A.; Ozeki, Yasuhiro

    2016-01-01

    MytiLec is an α-d-galactose-binding lectin with a unique primary structure isolated from the Mediterranean mussel (Mytilus galloprovincialis). The lectin adopts a β-trefoil fold that is also found in the B-sub-unit of ricin and other ricin-type (R-type) lectins. We are introducing MytiLec(-1) and its two variants (MytiLec-2 and -3), which both possess an additional pore-forming aerolysin-like domain, as members of a novel multi-genic “mytilectin family” in bivalve mollusks. Based on the full length mRNA sequence (911 bps), it was possible to elucidate the coding sequence of MytiLec-1, which displays an extended open reading frame (ORF) at the 5′ end of the sequence, confirmed both at the mRNA and at the genomic DNA sequence level. While this extension could potentially produce a polypeptide significantly longer than previously reported, this has not been confirmed yet at the protein level. MytiLec-1 was revealed to be encoded by a gene consisting of two exons and a single intron. The first exon comprised the 5′UTR and the initial ATG codon and it was possible to detect a putative promoter region immediately ahead of the transcription start site in the MytiLec-1 genomic locus. The remaining part of the MytiLec-1 coding sequence (including the three sub-domains, the 3′UTR and the poly-A signal) was included in the second exon. The bacteriostatic activity of MytiLec-1 was determined by the agglutination of both Gram-positive and Gram-negative bacteria, which was reversed by the co-presence of α-galactoside. Altogether, these data support the classification of MytiLec-1 as a member of the novel mytilectin family and suggest that this lectin may play an important role as a pattern recognition receptor in the innate immunity of mussels. PMID:27187419

  17. Carbon, oxygen, boron, hydrogen and nitrogen in the LEC growth of SI GaAs: a thermochemical approach

    NASA Astrophysics Data System (ADS)

    Korb, J.; Flade, T.; Jurisch, M.; Köhler, A.; Reinhold, Th; Weinert, B.

    1999-03-01

    The ChemSage code [Eriksson and Hack, Metall. Trans. B 12 (1990) 1013] to minimize the total Gibbs free energy was used to calculate phase equilibria in the complex thermochemical system representing LEC GaAs crystal growth which comprises the growth atmosphere, the liquid boron oxide, the GaAs melt and solid phases including the GaAs crystal. The behaviour of C, B, O, N and H in the crystal growth melt at 1509.42 K is investigated in dependence on relevant technological parameters.

  18. Influence of multi wafer annealing of LEC GaAs substrates on the quality of epitaxial layers

    SciTech Connect

    Forker, J.; Baeumler, M.; Weyher, J.L.; Jantz, W.

    1996-12-01

    The lateral distribution of dislocations and nonradiative recombination centers in bulk LEC GaAs is reproduced in the epilayer. Combined ingot/multi wafer annealing reduces the excess As concentration at dislocations and generates As matrix precipitates. We find that the presence of matrix precipitates does not adversely affect the epitaxial layer quality. On the other hand layer defects correlated with substrate dislocations are still visible. Hence either the ingot/wafer annealing does not sufficiently reduce dislocation-correlated substrate defects migrating into the epilayer. Alternatively, nonradiative recombination centers are generated during epitaxial growth near dislocations propagating from the substrate into the epilayer.

  19. Developments in uncooled IR technology at BAE SYSTEMS

    NASA Astrophysics Data System (ADS)

    Gurnee, Mark N.; Kohin, Margaret; Blackwell, Richard J.; Butler, Neal R.; Whitwam, Jason T.; Backer, Brian S.; Leary, Arthur R.; Nielson, Thomas

    2001-10-01

    Uncooled microbolometer thermal imaging sensor technology has begun to successfully address military, government and commercial applications in the real world. BAE SYSTEMS, located in Lexington MA, has been involved in the design and development of uncooled IR technology since the early 1980s. Our current MicroIRTM products are based on vanadium oxide (VOx) microbolometers. Thousands of uncooled microbolometer thermal imaging sensors are now being produced and sold annually. A the same time, applied research and development on the technology continues to improve the basic products and make them suitable for new applications. In this paper we report on the status and improvements achieved in the MicroIRTM product line, based on 320 X 240 element and 160 X 120 element FPA's with 46 μm pixel pitch. Other near term MicroIRTM products include 320 X 240 and 640 X 480 FPA's with 28 micrometers pixel pitch and measured sensitivities below 50 mK. In the systems area we discuss development and testing of a Light Thermal Weapon Sight (LTWS) for the U.S. Army, being developed by BAE SYSTEMS in partnership with Thales, based upon our uncooled MicroIRTM focal plane arrays (FPA) and systems. The LTWS prototypes were based upon our Standard Imaging Module SIM200, which employs our LAM2C, 320 X 240 element, microbolometer FPA. Finally we discuss the 480 X 640 element FPA and its application to the Heavy Thermal Weapon Sight application.

  20. Single-pixel polarimetric imaging.

    PubMed

    Durán, Vicente; Clemente, Pere; Fernández-Alonso, Mercedes; Tajahuerce, Enrique; Lancis, Jesús

    2012-03-01

    We present an optical system that performs Stokes polarimetric imaging with a single-pixel detector. This fact is possible by applying the theory of compressive sampling to the data acquired by a commercial polarimeter without spatial resolution. The measurement process is governed by a spatial light modulator, which sequentially generates a set of preprogrammed light intensity patterns. Experimental results are presented and discussed for an object that provides an inhomogeneous polarization distribution. PMID:22378406

  1. Representing SAR complex image pixels

    NASA Astrophysics Data System (ADS)

    Doerry, A. W.

    2016-05-01

    Synthetic Aperture Radar (SAR) images are often complex-valued to facilitate specific exploitation modes. Furthermore, these pixel values are typically represented with either real/imaginary (also known as I/Q) values, or as Magnitude/Phase values, with constituent components comprised of integers with limited number of bits. For clutter energy well below full-scale, Magnitude/Phase offers lower quantization noise than I/Q representation. Further improvement can be had with companding of the Magnitude value.

  2. SAR Image Complex Pixel Representations

    SciTech Connect

    Doerry, Armin W.

    2015-03-01

    Complex pixel values for Synthetic Aperture Radar (SAR) images of uniform distributed clutter can be represented as either real/imaginary (also known as I/Q) values, or as Magnitude/Phase values. Generally, these component values are integers with limited number of bits. For clutter energy well below full-scale, Magnitude/Phase offers lower quantization noise than I/Q representation. Further improvement can be had with companding of the Magnitude value.

  3. CMOS digital pixel sensors: technology and applications

    NASA Astrophysics Data System (ADS)

    Skorka, Orit; Joseph, Dileepan

    2014-04-01

    CMOS active pixel sensor technology, which is widely used these days for digital imaging, is based on analog pixels. Transition to digital pixel sensors can boost signal-to-noise ratios and enhance image quality, but can increase pixel area to dimensions that are impractical for the high-volume market of consumer electronic devices. There are two main approaches to digital pixel design. The first uses digitization methods that largely rely on photodetector properties and so are unique to imaging. The second is based on adaptation of a classical analog-to-digital converter (ADC) for in-pixel data conversion. Imaging systems for medical, industrial, and security applications are emerging lower-volume markets that can benefit from these in-pixel ADCs. With these applications, larger pixels are typically acceptable, and imaging may be done in invisible spectral bands.

  4. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Seshadri, Suresh (Inventor); Cole, David (Inventor); Smith, Roger M (Inventor); Hancock, Bruce R. (Inventor)

    2013-01-01

    The effects of inter pixel capacitance in a pixilated array may be measured by first resetting all pixels in the array to a first voltage, where a first image is read out, followed by resetting only a subset of pixels in the array to a second voltage, where a second image is read out, where the difference in the first and second images provide information about the inter pixel capacitance. Other embodiments are described and claimed.

  5. Recovery and recycling of limestone in LEC flue gas desulfurization. Final report, September 1, 1991--August 31, 1992

    SciTech Connect

    Gardner, N.C.; Boo, J.Y.; Culver, L.

    1992-09-01

    Prudich et. al. have proposed an attractive technology called Limestone Emission Control (LEC) for removing sulfur dioxide from flue gases. Beds of 1/8 inch wet limestone particles absorb the sulfur dioxide from the gases on contact. Sulfite and sulfate salts deposit on the surface of the particles; however, the gas never reaches the interior, limiting the limestone utilization to approximately 20% or less. The unreacted portion of the limestone can be recovered by mechanical grinding and recycling, enabling high overall sorbent utilization. Favorable economics are derived from small equipment, simplicity, and low sorbent costs. This project is a wet method for grinding and recovering the spent limestone from the LEC process, utilizing an impeller fluidizer, a new type of slurry processor. It consists of a cylindrical vessel with an impeller at one end. The impeller, driven at high rpm, concentrates the gravel size limestone in a rotating torus at the top of the cylinder, where the coating is abraded off by particle-particle impaction. The impeller generates sufficient pressure head to serve as a slurry pump. It combines the operation of wet grinding, washing, and transporting the spent and recovered limestone as an aqueous slurry. The fluidizer may be advantageous over dry grinding in the aspects of sharpness of separation, transport convenience, equipment erosion, and sorption bed cementation.

  6. Pixelated filters for spatial imaging

    NASA Astrophysics Data System (ADS)

    Mathieu, Karine; Lequime, Michel; Lumeau, Julien; Abel-Tiberini, Laetitia; Savin De Larclause, Isabelle; Berthon, Jacques

    2015-10-01

    Small satellites are often used by spatial agencies to meet scientific spatial mission requirements. Their payloads are composed of various instruments collecting an increasing amount of data, as well as respecting the growing constraints relative to volume and mass; So small-sized integrated camera have taken a favored place among these instruments. To ensure scene specific color information sensing, pixelated filters seem to be more attractive than filter wheels. The work presented here, in collaboration with Institut Fresnel, deals with the manufacturing of this kind of component, based on thin film technologies and photolithography processes. CCD detectors with a pixel pitch about 30 μm were considered. In the configuration where the matrix filters are positioned the closest to the detector, the matrix filters are composed of 2x2 macro pixels (e.g. 4 filters). These 4 filters have a bandwidth about 40 nm and are respectively centered at 550, 700, 770 and 840 nm with a specific rejection rate defined on the visible spectral range [500 - 900 nm]. After an intense design step, 4 thin-film structures have been elaborated with a maximum thickness of 5 μm. A run of tests has allowed us to choose the optimal micro-structuration parameters. The 100x100 matrix filters prototypes have been successfully manufactured with lift-off and ion assisted deposition processes. High spatial and spectral characterization, with a dedicated metrology bench, showed that initial specifications and simulations were globally met. These excellent performances knock down the technological barriers for high-end integrated specific multi spectral imaging.

  7. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    2004-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  8. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    2003-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  9. Proceedings of PIXEL98 -- International pixel detector workshop

    SciTech Connect

    Anderson, D.F.; Kwan, S.

    1998-08-01

    Experiments around the globe face new challenges of more precision in the face of higher interaction rates, greater track densities, and higher radiation doses, as they look for rarer and rarer processes, leading many to incorporate pixelated solid-state detectors into their plans. The highest-readout rate devices require new technologies for implementation. This workshop reviewed recent, significant progress in meeting these technical challenges. Participants presented many new results; many of them from the weeks--even days--just before the workshop. Brand new at this workshop were results on cryogenic operation of radiation-damaged silicon detectors (dubbed the Lazarus effect). Other new work included a diamond sensor with 280-micron collection distance; new results on breakdown in p-type silicon detectors; testing of the latest versions of read-out chip and interconnection designs; and the radiation hardness of deep-submicron processes.

  10. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    1995-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  11. Serial Pixel Analog-to-Digital Converter

    SciTech Connect

    Larson, E D

    2010-02-01

    This method reduces the data path from the counter to the pixel register of the analog-to-digital converter (ADC) from as many as 10 bits to a single bit. The reduction in data path width is accomplished by using a coded serial data stream similar to a pseudo random number (PRN) generator. The resulting encoded pixel data is then decoded into a standard hexadecimal format before storage. The high-speed serial pixel ADC concept is based on the single-slope integrating pixel ADC architecture. Previous work has described a massively parallel pixel readout of a similar architecture. The serial ADC connection is similar to the state-of-the art method with the exception that the pixel ADC register is a shift register and the data path is a single bit. A state-of-the-art individual-pixel ADC uses a single-slope charge integration converter architecture with integral registers and “one-hot” counters. This implies that parallel data bits are routed among the counter and the individual on-chip pixel ADC registers. The data path bit-width to the pixel is therefore equivalent to the pixel ADC bit resolution.

  12. Penrose Pixels for Super-Resolution.

    PubMed

    Ben-Ezra, M; Lin, Zhouchen; Wilburn, Bennett; Zhang, Wei

    2011-07-01

    We present a novel approach to reconstruction-based super-resolution that uses aperiodic pixel tilings, such as a Penrose tiling or a biological retina, for improved performance. To this aim, we develop a new variant of the well-known error back projection super-resolution algorithm that makes use of the exact detector model in its back projection operator for better accuracy. Pixels in our model can vary in shape and size, and there may be gaps between adjacent pixels. The algorithm applies equally well to periodic or aperiodic pixel tilings. We present analysis and extensive tests using synthetic and real images to show that our approach using aperiodic layouts substantially outperforms existing reconstruction-based algorithms for regular pixel arrays. We close with a discussion of the feasibility of manufacturing CMOS or CCD chips with pixels arranged in Penrose tilings.

  13. Dead pixel replacement in LWIR microgrid polarimeters.

    PubMed

    Ratliff, Bradley M; Tyo, J Scott; Boger, James K; Black, Wiley T; Bowers, David L; Fetrow, Matthew P

    2007-06-11

    LWIR imaging arrays are often affected by nonresponsive pixels, or "dead pixels." These dead pixels can severely degrade the quality of imagery and often have to be replaced before subsequent image processing and display of the imagery data. For LWIR arrays that are integrated with arrays of micropolarizers, the problem of dead pixels is amplified. Conventional dead pixel replacement (DPR) strategies cannot be employed since neighboring pixels are of different polarizations. In this paper we present two DPR schemes. The first is a modified nearest-neighbor replacement method. The second is a method based on redundancy in the polarization measurements.We find that the redundancy-based DPR scheme provides an order-of-magnitude better performance for typical LWIR polarimetric data. PMID:19547086

  14. Equivalence of a Bit Pixel Image to a Quantum Pixel Image

    NASA Astrophysics Data System (ADS)

    Ortega, Laurel Carlos; Dong, Shi-Hai; Cruz-Irisson, M.

    2015-11-01

    We propose a new method to transform a pixel image to the corresponding quantum-pixel using a qubit per pixel to represent each pixels classical weight in a quantum image matrix weight. All qubits are linear superposition, changing the coefficients level by level to the entire longitude of the gray scale with respect to the base states of the qubit. Classically, these states are just bytes represented in a binary matrix, having code combinations of 1 or 0 at all pixel locations. This method introduces a qubit-pixel image representation of images captured by classical optoelectronic methods. Supported partially by the project 20150964-SIP-IPN, Mexico

  15. Activation-efficiency modeling of silicon-ion implantation in undoped, LEC-grown GaAs

    SciTech Connect

    Bindal, A.

    1988-01-01

    Constructing an accurate GaAs MESFET modeling largely depends on a complete understanding of material properties by various characterization technique sand being able to obtain reproducible device parameters. In this work, the implanted material was evaluated with respect to various implantation and annealing conditions in detail. In investigating the activation efficiency of implanted silicon in LEC-grown GaAs, atomic and carrier distributions of the implant were obtained using Secondary Ion Mass Spectroscopy (SIMS), the conventional and steo-etch C-V techniques, respectively. Based on these experimental observations, the Si activation efficiency is found to be strong functions of the implantation fluence and annealing temperature, and weak functions of the implantation energy and annealing time. In understanding the effects of various implantation and annealing conditions on Si activation, the second part of this work is devoted to Photoluminescence (PL) and Deep Level Transient Spectroscopy (DLTS) experiments. The shallow defects were investigated by photoluminescence experiments.

  16. The antioxidant effect of DL-alpha-lipoic acid on copper-induced acute hepatitis in Long-Evans Cinnamon (LEC) rats.

    PubMed

    Yamamoto, H; Watanabe, T; Mizuno, H; Endo, K; Fukushige, J; Hosokawa, T; Kazusaka, A; Fujita, S

    2001-01-01

    The Long-Evans Cinnamon (LEC) rats, due to a genetic defect, accumulate excess copper (Cu) in the liver in a manner similar to patients with Wilson's disease and spontaneously develop acute hepatitis with severe jaundice. In this study we examined the protective effect of DL-alpha-Lipoic acid (LA) against acute hepatitis in LEC rats. LA was administered to LEC rats by gavage in doses of 10, 30 and 100 mg/kg five times per week, starting at 8-weeks-old and continuing till 12-weeks-old. Although LA had little effect against the increases in serum transaminase activities, it suppressed the loss of body weight and prevented severe jaundice in a dose-dependent manner. Antioxidant system analyses in liver showed that LA treatment significantly suppressed the inactivations of catalase and glutathione peroxidase, and the induction of heme oxygenase-1, an enzyme which is inducible under oxidative stress. Furthermore, LA showed dose-dependent suppressive effect against increase in nonheme iron contents of both cytosolic and crude mitochondrial fractions in a dose-dependent manner. Although at the highest dose, LA slightly suppressed the accumulation of Cu in crude mitochondrial fraction, it had no effect on the accumulation of Cu in cytosolic fraction. While LA completely suppressed the increase in lipid peroxidation (LPO) in the microsomal fraction at the highest dose, the suppressive effect against LPO in crude mitochondrial fractions was slight. From these results, it is concluded that LA has antioxidant effects at the molecular level against the development of Cu-induced hepatitis in LEC rats. Moreover, mitochondrial oxidative damage might be involved in the development of acute hepatitis in LEC rats.

  17. [Hadamard transform spectrometer mixed pixels' unmixing method].

    PubMed

    Yan, Peng; Hu, Bing-Liang; Liu, Xue-Bin; Sun, Wei; Li, Li-Bo; Feng, Yu-Tao; Liu, Yong-Zheng

    2011-10-01

    Hadamard transform imaging spectrometer is a multi-channel digital transform spectrometer detection technology, this paper based on digital micromirror array device (DMD) of the Hadamard transform spectrometer working principle and instrument structure, obtained by the imaging sensor mixed pixel were analyzed, theory derived the solution of pixel aliasing hybrid method, simulation results show that the method is simple and effective to improve the accuracy of mixed pixel spectrum more than 10% recovery. PMID:22250574

  18. Method for fabricating pixelated silicon device cells

    SciTech Connect

    Nielson, Gregory N.; Okandan, Murat; Cruz-Campa, Jose Luis; Nelson, Jeffrey S.; Anderson, Benjamin John

    2015-08-18

    A method, apparatus and system for flexible, ultra-thin, and high efficiency pixelated silicon or other semiconductor photovoltaic solar cell array fabrication is disclosed. A structure and method of creation for a pixelated silicon or other semiconductor photovoltaic solar cell array with interconnects is described using a manufacturing method that is simplified compared to previous versions of pixelated silicon photovoltaic cells that require more microfabrication steps.

  19. Commissioning of the CMS Forward Pixel Detector

    SciTech Connect

    Kumar, Ashish; /SUNY, Buffalo

    2008-12-01

    The Compact Muon Solenoid (CMS) experiment is scheduled for physics data taking in summer 2009 after the commissioning of high energy proton-proton collisions at Large Hadron Collider (LHC). At the core of the CMS all-silicon tracker is the silicon pixel detector, comprising three barrel layers and two pixel disks in the forward and backward regions, accounting for a total of 66 million channels. The pixel detector will provide high-resolution, 3D tracking points, essential for pattern recognition and precise vertexing, while being embedded in a hostile radiation environment. The end disks of the pixel detector, known as the Forward Pixel detector, has been assembled and tested at Fermilab, USA. It has 18 million pixel cells with dimension 100 x 150 {micro}m{sup 2}. The complete forward pixel detector was shipped to CERN in December 2007, where it underwent extensive system tests for commissioning prior to the installation. The pixel system was put in its final place inside the CMS following the installation and bake out of the LHC beam pipe in July 2008. It has been integrated with other sub-detectors in the readout since September 2008 and participated in the cosmic data taking. This report covers the strategy and results from commissioning of CMS forward pixel detector at CERN.

  20. Implementation of TDI based digital pixel ROIC with 15μm pixel pitch

    NASA Astrophysics Data System (ADS)

    Ceylan, Omer; Shafique, Atia; Burak, A.; Caliskan, Can; Abbasi, Shahbaz; Yazici, Melik; Gurbuz, Yasar

    2016-05-01

    A 15um pixel pitch digital pixel for LWIR time delay integration (TDI) applications is implemented which occupies one fourth of pixel area compared to previous digital TDI implementation. TDI is implemented on 8 pixels with oversampling rate of 2. ROIC provides 16 bits output with 8 bits of MSB and 8 bits of LSB. Pixel can store 75 M electrons with a quantization noise of 500 electrons. Digital pixel TDI implementation is advantageous over analog counterparts considering power consumption, chip area and signal-to-noise ratio. Digital pixel TDI ROIC is fabricated with 0.18um CMOS process. In digital pixel TDI implementation photocurrent is integrated on a capacitor in pixel and converted to digital data in pixel. This digital data triggers the summation counters which implements TDI addition. After all pixels in a row contribute, the summed data is divided to the number of TDI pixels(N) to have the actual output which is square root of N improved version of a single pixel output in terms of signal-to-noise-ratio (SNR).

  1. Ectopic overexpression of castor bean LEAFY COTYLEDON2 (LEC2) in Arabidopsis triggers the expression of genes that encode regulators of seed maturation and oil body proteins in vegetative tissues.

    PubMed

    Kim, Hyun Uk; Jung, Su-Jin; Lee, Kyeong-Ryeol; Kim, Eun Ha; Lee, Sang-Min; Roh, Kyung Hee; Kim, Jong-Bum

    2013-01-01

    The LEAFY COTYLEDON2 (LEC2) gene plays critically important regulatory roles during both early and late embryonic development. Here, we report the identification of the LEC2 gene from the castor bean plant (Ricinus communis), and characterize the effects of its overexpression on gene regulation and lipid metabolism in transgenic Arabidopsis plants. LEC2 exists as a single-copy gene in castor bean, is expressed predominantly in embryos, and encodes a protein with a conserved B3 domain, but different N- and C-terminal domains to those found in LEC2 from Arabidopsis. Ectopic overexpression of LEC2 from castor bean under the control of the cauliflower mosaic virus (CaMV) 35S promoter in Arabidopsis plants induces the accumulation of transcripts that encodes five major transcription factors (the LEAFY COTYLEDON1 (LEC1), LEAFY COTYLEDON1-LIKE (L1L), FUSCA3 (FUS3), and ABSCISIC ACID INSENSITIVE 3 (ABI3) transcripts for seed maturation, and WRINKELED1 (WRI1) transcripts for fatty acid biosynthesis), as well as OLEOSIN transcripts for the formation of oil bodies in vegetative tissues. Transgenic Arabidopsis plants that express the LEC2 gene from castor bean show a range of dose-dependent morphological phenotypes and effects on the expression of LEC2-regulated genes during seedling establishment and vegetative growth. Expression of castor bean LEC2 in Arabidopsis increased the expression of fatty acid elongase 1 (FAE1) and induced the accumulation of triacylglycerols, especially those containing the seed-specific fatty acid, eicosenoic acid (20:1(Δ11)), in vegetative tissues.

  2. Ectopic overexpression of castor bean LEAFY COTYLEDON2 (LEC2) in Arabidopsis triggers the expression of genes that encode regulators of seed maturation and oil body proteins in vegetative tissues☆

    PubMed Central

    Kim, Hyun Uk; Jung, Su-Jin; Lee, Kyeong-Ryeol; Kim, Eun Ha; Lee, Sang-Min; Roh, Kyung Hee; Kim, Jong-Bum

    2013-01-01

    The LEAFY COTYLEDON2 (LEC2) gene plays critically important regulatory roles during both early and late embryonic development. Here, we report the identification of the LEC2 gene from the castor bean plant (Ricinus communis), and characterize the effects of its overexpression on gene regulation and lipid metabolism in transgenic Arabidopsis plants. LEC2 exists as a single-copy gene in castor bean, is expressed predominantly in embryos, and encodes a protein with a conserved B3 domain, but different N- and C-terminal domains to those found in LEC2 from Arabidopsis. Ectopic overexpression of LEC2 from castor bean under the control of the cauliflower mosaic virus (CaMV) 35S promoter in Arabidopsis plants induces the accumulation of transcripts that encodes five major transcription factors (the LEAFY COTYLEDON1 (LEC1), LEAFY COTYLEDON1-LIKE (L1L), FUSCA3 (FUS3), and ABSCISIC ACID INSENSITIVE 3 (ABI3) transcripts for seed maturation, and WRINKELED1 (WRI1) transcripts for fatty acid biosynthesis), as well as OLEOSIN transcripts for the formation of oil bodies in vegetative tissues. Transgenic Arabidopsis plants that express the LEC2 gene from castor bean show a range of dose-dependent morphological phenotypes and effects on the expression of LEC2-regulated genes during seedling establishment and vegetative growth. Expression of castor bean LEC2 in Arabidopsis increased the expression of fatty acid elongase 1 (FAE1) and induced the accumulation of triacylglycerols, especially those containing the seed-specific fatty acid, eicosenoic acid (20:1Δ11), in vegetative tissues. PMID:24363987

  3. High stroke pixel for a deformable mirror

    DOEpatents

    Miles, Robin R.; Papavasiliou, Alexandros P.

    2005-09-20

    A mirror pixel that can be fabricated using standard MEMS methods for a deformable mirror. The pixel is electrostatically actuated and is capable of the high deflections needed for spaced-based mirror applications. In one embodiment, the mirror comprises three layers, a top or mirror layer, a middle layer which consists of flexures, and a comb drive layer, with the flexures of the middle layer attached to the mirror layer and to the comb drive layer. The comb drives are attached to a frame via spring flexures. A number of these mirror pixels can be used to construct a large mirror assembly. The actuator for the mirror pixel may be configured as a crenellated beam with one end fixedly secured, or configured as a scissor jack. The mirror pixels may be used in various applications requiring high stroke adaptive optics.

  4. Sub-pixel mapping of water boundaries using pixel swapping algorithm (case study: Tagliamento River, Italy)

    NASA Astrophysics Data System (ADS)

    Niroumand-Jadidi, Milad; Vitti, Alfonso

    2015-10-01

    Taking the advantages of remotely sensed data for mapping and monitoring of water boundaries is of particular importance in many different management and conservation activities. Imagery data are classified using automatic techniques to produce maps entering the water bodies' analysis chain in several and different points. Very commonly, medium or coarse spatial resolution imagery is used in studies of large water bodies. Data of this kind is affected by the presence of mixed pixels leading to very outstanding problems, in particular when dealing with boundary pixels. A considerable amount of uncertainty inescapably occurs when conventional hard classifiers (e.g., maximum likelihood) are applied on mixed pixels. In this study, Linear Spectral Mixture Model (LSMM) is used to estimate the proportion of water in boundary pixels. Firstly by applying an unsupervised clustering, the water body is identified approximately and a buffer area considered ensuring the selection of entire boundary pixels. Then LSMM is applied on this buffer region to estimate the fractional maps. However, resultant output of LSMM does not provide a sub-pixel map corresponding to water abundances. To tackle with this problem, Pixel Swapping (PS) algorithm is used to allocate sub-pixels within mixed pixels in such a way to maximize the spatial proximity of sub-pixels and pixels in the neighborhood. The water area of two segments of Tagliamento River (Italy) are mapped in sub-pixel resolution (10m) using a 30m Landsat image. To evaluate the proficiency of the proposed approach for sub-pixel boundary mapping, the image is also classified using a conventional hard classifier. A high resolution image of the same area is also classified and used as a reference for accuracy assessment. According to the results, sub-pixel map shows in average about 8 percent higher overall accuracy than hard classification and fits very well in the boundaries with the reference map.

  5. Pixel multichip module development at Fermilab

    SciTech Connect

    Turqueti, M A; Cardoso, G; Andresen, J; Appel, J A; Christian, D C; Kwan, S W; Prosser, A; Uplegger, L

    2005-10-01

    At Fermilab, there is an ongoing pixel detector R&D effort for High Energy Physics with the objective of developing high performance vertex detectors suitable for the next generation of HEP experiments. The pixel module presented here is a direct result of work undertaken for the canceled BTeV experiment. It is a very mature piece of hardware, having many characteristics of high performance, low mass and radiation hardness driven by the requirements of the BTeV experiment. The detector presented in this paper consists of three basic devices; the readout integrated circuit (IC) FPIX2A [2][5], the pixel sensor (TESLA p-spray) [6] and the high density interconnect (HDI) flex circuit [1][3] that is capable of supporting eight readout ICs. The characterization of the pixel multichip module prototype as well as the baseline design of the eight chip pixel module and its capabilities are presented. These prototypes were characterized for threshold and noise dispersion. The bump-bonds of the pixel module were examined using an X-ray inspection system. Furthermore, the connectivity of the bump-bonds was tested using a radioactive source ({sup 90}Sr), while the absolute calibration of the modules was achieved using an X-ray source. This paper provides a view of the integration of the three components that together comprise the pixel multichip module.

  6. Micro-Pixel Image Position Sensing Testbed

    NASA Technical Reports Server (NTRS)

    Nemati, Bijan; Shao, Michael; Zhai, Chengxing; Erlig, Hernan; Wang, Xu; Goullioud, Renaud

    2011-01-01

    The search for Earth-mass planets in the habitable zones of nearby Sun-like stars is an important goal of astrophysics. This search is not feasible with the current slate of astronomical instruments. We propose a new concept for microarcsecond astrometry which uses a simplified instrument and hence promises to be low cost. The concept employs a telescope with only a primary, laser metrology applied to the focal plane array, and new algorithms for measuring image position and displacement on the focal plane. The required level of accuracy in both the metrology and image position sensing is at a few micro-pixels. We have begun a detailed investigation of the feasibility of our approach using simulations and a micro-pixel image position sensing testbed called MCT. So far we have been able to demonstrate that the pixel-to-pixel distances in a focal plane can be measured with a precision of 20 micro-pixels and image-to-image distances with a precision of 30 micro-pixels. We have also shown using simulations that our image position algorithm can achieve accuracy of 4 micro-pixels in the presence of lambda/20 wavefront errors.

  7. It's not the pixel count, you fool

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    2012-01-01

    The first thing a "marketing guy" asks the digital camera engineer is "how many pixels does it have, for we need as many mega pixels as possible since the other guys are killing us with their "umpteen" mega pixel pocket sized digital cameras. And so it goes until the pixels get smaller and smaller in order to inflate the pixel count in the never-ending pixel-wars. These small pixels just are not very good. The truth of the matter is that the most important feature of digital cameras in the last five years is the automatic motion control to stabilize the image on the sensor along with some very sophisticated image processing. All the rest has been hype and some "cool" design. What is the future for digital imaging and what will drive growth of camera sales (not counting the cell phone cameras which totally dominate the market in terms of camera sales) and more importantly after sales profits? Well sit in on the Dark Side of Color and find out what is being done to increase the after sales profits and don't be surprised if has been done long ago in some basement lab of a photographic company and of course, before its time.

  8. Investigation of asymmetry effects in a heater-magnet module for TMF VGF and LEC growth by three-dimensional numerical modeling

    NASA Astrophysics Data System (ADS)

    Kasjanow, H.; Nacke, B.; Eichler, St.; Jockel, D.; Frank-Rotsch, Ch.; Lange, P.; Kießling, F.-M.; Rudolph, P.

    2008-04-01

    Three-dimensional (3D) electromagnetic computer modeling is used to analyze the effects of asymmetry at the crystal growth by the vertical gradient freeze (VGF) and liquid encapsulation Czochralski (LEC) methods under traveling magnetic fields (TMF). Based on the results a heater-magnet module (HMM), combining the generation of heat and induction of magnetic field, was developed and optimized. It will be shown that asymmetry effects are caused by the designs of the heater-magnet coils and bus bars. They are enforced when a TMF of higher frequencies is used. It can be concluded that for VGF arrangements without container rotation the module design must be modified. Compared to that in case of LEC the effect of asymmetry can be effectively graduated by crucible and crystal rotations.

  9. LISe pixel detector for neutron imaging

    NASA Astrophysics Data System (ADS)

    Herrera, Elan; Hamm, Daniel; Wiggins, Brenden; Milburn, Rob; Burger, Arnold; Bilheux, Hassina; Santodonato, Louis; Chvala, Ondrej; Stowe, Ashley; Lukosi, Eric

    2016-10-01

    Semiconducting lithium indium diselenide, 6LiInSe2 or LISe, has promising characteristics for neutron detection applications. The 95% isotopic enrichment of 6Li results in a highly efficient thermal neutron-sensitive material. In this study, we report on a proof-of-principle investigation of a semiconducting LISe pixel detector to demonstrate its potential as an efficient neutron imager. The LISe pixel detector had a 4×4 of pixels with a 550 μm pitch on a 5×5×0.56 mm3 LISe substrate. An experimentally verified spatial resolution of 300 μm was observed utilizing a super-sampling technique.

  10. Per-Pixel Lighting Data Analysis

    SciTech Connect

    Inanici, Mehlika

    2005-08-01

    This report presents a framework for per-pixel analysis of the qualitative and quantitative aspects of luminous environments. Recognizing the need for better lighting analysis capabilities and appreciating the new measurement abilities developed within the LBNL Lighting Measurement and Simulation Toolbox, ''Per-pixel Lighting Data Analysis'' project demonstrates several techniques for analyzing luminance distribution patterns, luminance ratios, adaptation luminance and glare assessment. The techniques are the syntheses of the current practices in lighting design and the unique practices that can be done with per-pixel data availability. Demonstrated analysis techniques are applicable to both computer-generated and digitally captured images (physically-based renderings and High Dynamic Range photographs).

  11. Pilot-scale limestone emission control (LEC) process: A development project. Volume 1: Main report and appendices A, B, C, and D. Final report

    SciTech Connect

    Not Available

    1994-03-01

    ETS, Inc., a pollution consulting firm with headquarters in Roanoke, Virginia, has developed a dry, limestone-based flue gas desulfurization (FGD) system. This SO{sub 2} removal system, called Limestone Emission Control (LEC), can be designed for installation on either new or existing coal-fired boilers. In the LEC process, the SO{sub 2} in the flue gas reacts with wetted granular limestone that is contained in a moving bed. A surface layer of principally calcium sulfate (CaSO{sub 4}) is formed on the limestone. Periodic removal of this surface layer by mechanical agitation allows high utilization of the limestone granules. The primary goal of the current study is the demonstration of the techno/economic capability of the LEC system as a post-combustion FGD process capable of use in both existing and future coal-fired boiler facilities burning high-sulfur coal. A nominal 5,000 acfm LEC pilot plant has been designed, fabricated and installed on the slipstream of a 70,000 pph stoker boiler providing steam to Ohio University`s Athens, Ohio campus. The pilot plant was normally operated on the slipstream of the Ohio Univ. boiler plant flue gas, but also had the capability of operating at higher inlet SO{sub 2} concentrations (typically equivalent to 3-1/2% sulfur coal) than those normally available from the flue gas slipstream. This was accomplished by injecting SO{sub 2} gas into the slipstream inlet. The pilot plant was instrumented to provide around-the-clock operation and was fully outfitted with temperature, SO{sub 2}, gas flow and pressure drop monitors.

  12. Performance improvements for VOx microbolometer FPAs

    NASA Astrophysics Data System (ADS)

    Murphy, Daniel F.; Ray, Michael; Wyles, Jessica; Asbrock, James F.; Hewitt, C.; Wyles, Richard; Gordon, Eli; Sessler, T.; Kennedy, Adam; Baur, Stefan T.; Van Lue, David; Anderson, Steven; Chin, Richard; Gonzales, H.; Le Pere, C.; Ton, S.; Kostrzewa, Thomas

    2004-08-01

    Raytheon is producing high-quality 320 x 240 microbolometer FPAs with 25 μm pitch pixels. The 320 x 240 FPAs have a sensitivity that is comparable to microbolometer FPAs with 50 μm pixels. Typical NETD values for these FPAs are <50mK with an f/1 aperture and operating at 30 Hz frame rates. Pixel operability is greater than 99.9% on most FPAs, and uncorrected responsivity nonuniformity is less than 4% (sigma/mean). These 25 μm microbolometer detectors also have a relatively fast thermal time constant of approximately 10 msec. These arrays have produced excellent image quality, and are currently fielded in a variety of demonstration systems. The pixel size reduction facilitates a significant FPA cost reduction since the number of die printed on a wafer can be increased, and also has enabled the development of a large-format 640 x 480 FPA array. Raytheon is producing these arrays with excellent sensitivity and typical NETD values of <50mK with an f/1 aperture and operating at 30 Hz frame rates. These arrays have excellent operability and image quality. Several dual FOV prototype 640 x 480 systems have been delivered under the LCMS and UAV programs. RVS has developed a flexible uncooled front end (UFE) electronics that will serve as the basis for the camera engine systems using 320 x 240 arrays. RVS has developed a 640 x 480 Common Uncooled Engine (CUE) which is intended for small pixel, high performance applications. The CUE is the ideal cornerstone for ground and airborne systems, multi-mode sensor, weapon sight or seeker architectures, and commercial surveillance.

  13. Pixels, Imagers and Related Fabrication Methods

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)

    2016-01-01

    Pixels, imagers and related fabrication methods are described. The described methods result in cross-talk reduction in imagers and related devices by generating depletion regions. The devices can also be used with electronic circuits for imaging applications.

  14. Pixels, Imagers and Related Fabrication Methods

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)

    2014-01-01

    Pixels, imagers and related fabrication methods are described. The described methods result in cross-talk reduction in imagers and related devices by generating depletion regions. The devices can also be used with electronic circuits for imaging applications.

  15. Fabrication and evaluation of room temperature operated radiation detectors processed from undoped LEC bulk gallium arsenide material

    SciTech Connect

    McGregor, D.S.; Knoll, G.F.; Eisen, Y.; Brake, R.

    1994-09-01

    Semi-insulating undoped bulk LEC GaAs was investigated as a possible detector material for room temperature operated charged particle and gamma ray spectrometers. GaAs Schottky based diode detectors were fabricated with thicknesses of 45 microns, 100 microns, 250 microns, and 750 microns. Pulse height analysis utilizing an alpha particle source disclosed non-constant electric field distributions that decreased rapidly from the Schottky contact into the bulk of the detectors. Results from pulsed X-ray analysis and the alpha particle pulse height analysis indicate an active region width voltage dependence that strongly deviates from {radical}{bar V} behavior. Resolution at room temperature for {sup 241}Am alpha particles ranged from 2.2% to 3.1% FWHM for different detectors with a typical resolution of 2.5% FWHM. Room temperature measurements of 60 keV gamma rays ({sup 24l}Am) and 122 keV gamma rays ({sup 57}Co) resulted in observed full energy peaks with FWHM`s of 22 keV and 40 keV, respectively.

  16. Optimizing the Multivalent Binding of the Bacterial Lectin LecA by Glycopeptide Dendrimers for Therapeutic Purposes.

    PubMed

    Bouvier, Benjamin

    2016-06-27

    Bacterial lectins are nonenzymatic sugar-binding proteins involved in the formation of biofilms and the onset of virulence. The weakness of individual sugar-lectin interactions is compensated by the potentially large number of simultaneous copies of such contacts, resulting in high overall sugar-lectin affinities and marked specificities. Therapeutic compounds functionalized with sugar residues can compete with the host glycans for binding to lectins only if they are able to take advantage of this multivalent binding mechanism. Glycopeptide dendrimers, featuring treelike topologies with sugar moieties at their leaves, have already shown great promise in this regard. However, optimizing the dendrimers' amino acid sequence is necessary to match the dynamics of the lectin active sites with that of the multivalent ligands. This work combines long-time-scale coarse-grained simulations of dendrimers and lectins with a reasoned exploration of the dendrimer sequence space in an attempt to suggest sequences that could maximize multivalent binding to the galactose-specific bacterial lectin LecA. These candidates are validated by simulations of mixed dendrimer/lectin solutions, and the effects of the dendrimers on lectin dynamics are discussed. This approach is an attractive first step in the conception of therapeutic compounds based on the dendrimer scaffold and contributes to the understanding of the various classes of multivalency that underpin the ubiquitous "sugar code". PMID:27223679

  17. Design of the small pixel pitch ROIC

    NASA Astrophysics Data System (ADS)

    Liang, Qinghua; Jiang, Dazhao; Chen, Honglei; Zhai, Yongcheng; Gao, Lei; Ding, Ruijun

    2014-11-01

    Since the technology trend of the third generation IRFPA towards resolution enhancing has steadily progressed,the pixel pitch of IRFPA has been greatly reduced.A 640×512 readout integrated circuit(ROIC) of IRFPA with 15μm pixel pitch is presented in this paper.The 15μm pixel pitch ROIC design will face many challenges.As we all known,the integrating capacitor is a key performance parameter when considering pixel area,charge capacity and dynamic range,so we adopt the effective method of 2 by 2 pixels sharing an integrating capacitor to solve this problem.The input unit cell architecture will contain two paralleled sample and hold parts,which not only allow the FPA to be operated in full frame snapshot mode but also save relatively unit circuit area.Different applications need more matching input unit circuits. Because the dimension of 2×2 pixels is 30μm×30μm, an input stage based on direct injection (DI) which has medium injection ratio and small layout area is proved to be suitable for middle wave (MW) while BDI with three-transistor cascode amplifier for long wave(LW). By adopting the 0.35μm 2P4M mixed signal process, the circuit architecture can make the effective charge capacity of 7.8Me- per pixel with 2.2V output range for MW and 7.3 Me- per pixel with 2.6V output range for LW. According to the simulation results, this circuit works well under 5V power supply and achieves less than 0.1% nonlinearity.

  18. Steganography based on pixel intensity value decomposition

    NASA Astrophysics Data System (ADS)

    Abdulla, Alan Anwar; Sellahewa, Harin; Jassim, Sabah A.

    2014-05-01

    This paper focuses on steganography based on pixel intensity value decomposition. A number of existing schemes such as binary, Fibonacci, Prime, Natural, Lucas, and Catalan-Fibonacci (CF) are evaluated in terms of payload capacity and stego quality. A new technique based on a specific representation is proposed to decompose pixel intensity values into 16 (virtual) bit-planes suitable for embedding purposes. The proposed decomposition has a desirable property whereby the sum of all bit-planes does not exceed the maximum pixel intensity value, i.e. 255. Experimental results demonstrate that the proposed technique offers an effective compromise between payload capacity and stego quality of existing embedding techniques based on pixel intensity value decomposition. Its capacity is equal to that of binary and Lucas, while it offers a higher capacity than Fibonacci, Prime, Natural, and CF when the secret bits are embedded in 1st Least Significant Bit (LSB). When the secret bits are embedded in higher bit-planes, i.e., 2nd LSB to 8th Most Significant Bit (MSB), the proposed scheme has more capacity than Natural numbers based embedding. However, from the 6th bit-plane onwards, the proposed scheme offers better stego quality. In general, the proposed decomposition scheme has less effect in terms of quality on pixel value when compared to most existing pixel intensity value decomposition techniques when embedding messages in higher bit-planes.

  19. Sensor development for the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Bolla, G.; Bortoletto, D.; Horisberger, R.; Kaufmann, R.; Rohe, T.; Roy, A.

    2002-06-01

    The CMS experiment which is currently under construction at the Large Hadron Collider (LHC) at CERN (Geneva, Switzerland) will contain a pixel detector which provides in its final configuration three space points per track close to the interaction point of the colliding beams. Because of the harsh radiation environment of the LHC, the technical realization of the pixel detector is extremely challenging. The readout chip as the most damageable part of the system is believed to survive a particle fluence of 6×10 14 neq/ cm2 (All fluences are normalized to 1 MeV neutrons and therefore all components of the hybrid pixel detector have to perform well up to at least this fluence. As this requires a partially depleted operation of the silicon sensors after irradiation-induced type inversion of the substrate, an "n in n" concept has been chosen. In order to perform IV-tests on wafer level and to hold accidentally unconnected pixels close to ground potential, a resistive path between the pixels has been implemented by the openings in the p-stop implants surrounding every pixel cell. A prototype of such sensors has been produced by two different companies and especially the properties of these resistors have extensively been tested before and after irradiation.

  20. Small pixel oversampled IR focal plane arrays

    NASA Astrophysics Data System (ADS)

    Caulfield, John; Curzan, Jon; Lewis, Jay; Dhar, Nibir

    2015-06-01

    We report on a new high definition high charge capacity 2.1 Mpixel MWIR Infrared Focal Plane Array. This high definition (HD) FPA utilizes a small 5 um pitch pixel size which is below the Nyquist limit imposed by the optical systems Point Spread Function (PSF). These smaller sub diffraction limited pixels allow spatial oversampling of the image. We show that oversampling IRFPAs enables improved fidelity in imaging including resolution improvements, advanced pixel correlation processing to reduce false alarm rates, improved detection ranges, and an improved ability to track closely spaced objects. Small pixel HD arrays are viewed as the key component enabling lower size, power and weight of the IR Sensor System. Small pixels enables a reduction in the size of the systems components from the smaller detector and ROIC array, the reduced optics focal length and overall lens size, resulting in an overall compactness in the sensor package, cooling and associated electronics. The highly sensitive MWIR small pixel HD FPA has the capability to detect dimmer signals at longer ranges than previously demonstrated.

  1. Performances of THz cameras with enhanced sensitivity in sub-terahertz region

    NASA Astrophysics Data System (ADS)

    Oda, Naoki; Ishi, Tsutomu; Kurashina, Seiji; Sudou, Takayuki; Morimoto, Takao; Miyoshi, Masaru; Doi, Kohei; Goto, Hideki; Sasaki, Tokuhito; Isoyama, Goro; Kato, Ryukou; Irizawa, Akinori; Kawase, Keigo

    2015-05-01

    Uncooled microbolometer-type 640x480 and 320x240 Terahertz (THz) focal plane arrays (FPAs) with enhanced sensitivity in sub-THz region are developed, and incorporated into 640x480 and 320x240 cameras, respectively. The pixel in the THz-FPA has such a structure that an area sensitive to electromagnetic wave is suspended above read-out integrated circuit (ROIC). A thin metallic layer is formed on the top of the sensitive area, while a thick metallic layer is formed on the surface of ROIC. The structure composed of the thin metallic layer and the thick metallic layer behaves as an optical cavity. The THz-FPAs reported in this paper have a modified pixel structure which has several times longer optical-cavity length than NEC's previous pixel does, by forming a thick SiN layer on the ROIC. The extended optical-cavity structure is favorable for detecting electromagnetic wave with lower frequency. Consequently, the Minimum Detectable Power per pixel (MDP) is improved ten times in sub-THz region, especially 0.5-0.6 THz. This paper presents spectral frequency dependences of MDP values for THz-FPA with the modified pixel structure and THz-FPA with the previous pixel structure, using THz free electron laser (FEL) developed by Osaka University. The modification of pixel structure extends high sensitivity region to lower frequency region, such as sub-THz region, and the wider spectral coverage of THz camera surely expands its applicability

  2. Focal plane array with modular pixel array components for scalability

    DOEpatents

    Kay, Randolph R; Campbell, David V; Shinde, Subhash L; Rienstra, Jeffrey L; Serkland, Darwin K; Holmes, Michael L

    2014-12-09

    A modular, scalable focal plane array is provided as an array of integrated circuit dice, wherein each die includes a given amount of modular pixel array circuitry. The array of dice effectively multiplies the amount of modular pixel array circuitry to produce a larger pixel array without increasing die size. Desired pixel pitch across the enlarged pixel array is preserved by forming die stacks with each pixel array circuitry die stacked on a separate die that contains the corresponding signal processing circuitry. Techniques for die stack interconnections and die stack placement are implemented to ensure that the desired pixel pitch is preserved across the enlarged pixel array.

  3. Spatial clustering of pixels of a multispectral image

    SciTech Connect

    Conger, James Lynn

    2014-08-19

    A method and system for clustering the pixels of a multispectral image is provided. A clustering system computes a maximum spectral similarity score for each pixel that indicates the similarity between that pixel and the most similar neighboring. To determine the maximum similarity score for a pixel, the clustering system generates a similarity score between that pixel and each of its neighboring pixels and then selects the similarity score that represents the highest similarity as the maximum similarity score. The clustering system may apply a filtering criterion based on the maximum similarity score so that pixels with similarity scores below a minimum threshold are not clustered. The clustering system changes the current pixel values of the pixels in a cluster based on an averaging of the original pixel values of the pixels in the cluster.

  4. Pixel Dynamics Analysis of Photospheric Spectral Data

    NASA Astrophysics Data System (ADS)

    Rasca, Anthony P.; Chen, James; Pevtsov, Alexei A.

    2015-04-01

    Recent advances in solar observations have led to higher-resolution surface (photosphere) images that reveal bipolar magnetic features operating near the resolution limit during emerging flux events. Further improvements in resolution are expected to reveal even smaller dynamic features. Such photospheric features provide observable indications of what is happening before, during, and after flux emergence, eruptions in the corona, and other phenomena. Visible changes in photospheric active regions also play a major role in predicting eruptions that are responsible for geomagnetic plasma disturbances. A new method has been developed to extract physical information from photospheric data (e.g., SOLIS Stokes parameters) based on the statistics of pixel-by-pixel variations in spectral (absorption or emission) line quantities such as line profile Doppler shift, width, asymmetry, and flatness. Such properties are determined by the last interaction between detected photons and optically thick photospheric plasmas, and may contain extractable information on local plasma properties at sub-pixel scales. Applying the method to photospheric data with high spectral resolution, our pixel-by-pixel analysis is performed for various regions on the solar disk, ranging from quiet-Sun regions to active regions exhibiting eruptions, characterizing photospheric dynamics using spectral profiles. In particular, the method quantitatively characterizes the time profile of changes in spectral properties in photospheric features and provides improved physical constraints on observed quantities.

  5. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Seshadri, S.; Cole, D. M.; Hancock, B. R.; Smith, R. M.

    2008-01-01

    Electronic coupling effects such as Inter-Pixel Capacitance (IPC) affect the quantitative interpretation of image data from CMOS, hybrid visible and infrared imagers alike. Existing methods of characterizing IPC do not provide a map of the spatial variation of IPC over all pixels. We demonstrate a deterministic method that provides a direct quantitative map of the crosstalk across an imager. The approach requires only the ability to reset single pixels to an arbitrary voltage, different from the rest of the imager. No illumination source is required. Mapping IPC independently for each pixel is also made practical by the greater S/N ratio achievable for an electrical stimulus than for an optical stimulus, which is subject to both Poisson statistics and diffusion effects of photo-generated charge. The data we present illustrates a more complex picture of IPC in Teledyne HgCdTe and HyViSi focal plane arrays than is presently understood, including the presence of a newly discovered, long range IPC in the HyViSi FPA that extends tens of pixels in distance, likely stemming from extended field effects in the fully depleted substrate. The sensitivity of the measurement approach has been shown to be good enough to distinguish spatial structure in IPC of the order of 0.1%.

  6. Pixels, Blocks of Pixels, and Polygons: Choosing a Spatial Unit for Thematic Accuracy Assessment

    EPA Science Inventory

    Pixels, polygons, and blocks of pixels are all potentially viable spatial assessment units for conducting an accuracy assessment. We develop a statistical population-based framework to examine how the spatial unit chosen affects the outcome of an accuracy assessment. The populati...

  7. Uncooled infrared detectors toward smaller pixel pitch with newly proposed pixel structure

    NASA Astrophysics Data System (ADS)

    Tohyama, Shigeru; Sasaki, Tokuhito; Endoh, Tsutomu; Sano, Masahiko; Katoh, Kouji; Kurashina, Seiji; Miyoshi, Masaru; Yamazaki, Takao; Ueno, Munetaka; Katayama, Haruyoshi; Imai, Tadashi

    2011-06-01

    Since authors have successfully demonstrated uncooled infrared (IR) focal plane array (FPA) with 23.5 um pixel pitch, it has been widely utilized for commercial applications such as thermography, security camera and so on. One of the key issues for uncooled IR detector technology is to shrink the pixel size. The smaller the pixel pitch, the more the IR camera products become compact and the less cost. This paper proposes a new pixel structure with a diaphragm and beams which are placed in different level, to realize an uncooled IRFPA with smaller pixel pitch )<=17 μm). The upper level consists of diaphragm with VOx bolometer and IR absorber layers, while the lower level consists of the two beams, which are designed to place on the adjacent pixels. The test devices of this pixel design with 12 um, 15 um and 17 um pitch have been fabricated on the Si ROIC of QVGA (320 × 240) with 23.5 um pitch. Their performances reveal nearly equal to the IRFPA with 23.5 um pitch. For example, noise equivalent temperature difference (NETD) of 12 μm pixel is 63.1 mK with thermal time constant of 14.5 msec. In addition, this new structure is expected to be more effective for the existing IRFPA with 23.5 um pitch in order to improve the IR responsivity.

  8. Development of CMOS Pixel Sensors with digital pixel dedicated to future particle physics experiments

    NASA Astrophysics Data System (ADS)

    Zhao, W.; Wang, T.; Pham, H.; Hu-Guo, C.; Dorokhov, A.; Hu, Y.

    2014-02-01

    Two prototypes of CMOS pixel sensor with in-pixel analog to digital conversion have been developed in a 0.18 μm CIS process. The first design integrates a discriminator into each pixel within an area of 22 × 33 μm2 in order to meet the requirements of the ALICE inner tracking system (ALICE-ITS) upgrade. The second design features 3-bit charge encoding inside a 35 × 35 μm2 pixel which is motivated by the specifications of the outer layers of the ILD vertex detector (ILD-VXD). This work aims to validate the concept of in-pixel digitization which offers higher readout speed, lower power consumption and less dead zone compared with the column-level charge encoding.

  9. Optical links for the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Stucci, Stefania

    2016-07-01

    With the expected increase in the instantaneous luminosity of the LHC in the next few years, the off-detector optical read-out system of the outer two layers of the Pixel Detector of the ATLAS experiment will reach its bandwidth limits. The bandwidth will be increased with new optical receivers, which had to be redesigned since commercial solutions could not be used. The new design allows for a wider operational range in terms of data frequency and input optical power to match the on-detector transmitters of the present Pixel Detector. We report on the design and testing of prototypes of these components and the plans for the installation in the Pixel Detector read-out chain in 2015.

  10. Power Studies for the CMS Pixel Tracker

    SciTech Connect

    Todri, A.; Turqueti, M.; Rivera, R.; Kwan, S.; /Fermilab

    2009-01-01

    The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory is carrying out R&D investigations for the upgrade of the power distribution system of the Compact Muon Solenoid (CMS) Pixel Tracker at the Large Hadron Collider (LHC). Among the goals of this effort is that of analyzing the feasibility of alternative powering schemes for the forward tracker, including DC to DC voltage conversion techniques using commercially available and custom switching regulator circuits. Tests of these approaches are performed using the PSI46 pixel readout chip currently in use at the CMS Tracker. Performance measures of the detector electronics will include pixel noise and threshold dispersion results. Issues related to susceptibility to switching noise will be studied and presented. In this paper, we describe the current power distribution network of the CMS Tracker, study the implications of the proposed upgrade with DC-DC converters powering scheme and perform noise susceptibility analysis.

  11. Vivid, full-color aluminum plasmonic pixels

    PubMed Central

    Olson, Jana; Manjavacas, Alejandro; Liu, Lifei; Chang, Wei-Shun; Foerster, Benjamin; King, Nicholas S.; Knight, Mark W.; Nordlander, Peter; Halas, Naomi J.; Link, Stephan

    2014-01-01

    Aluminum is abundant, low in cost, compatible with complementary metal-oxide semiconductor manufacturing methods, and capable of supporting tunable plasmon resonance structures that span the entire visible spectrum. However, the use of Al for color displays has been limited by its intrinsically broad spectral features. Here we show that vivid, highly polarized, and broadly tunable color pixels can be produced from periodic patterns of oriented Al nanorods. Whereas the nanorod longitudinal plasmon resonance is largely responsible for pixel color, far-field diffractive coupling is used to narrow the plasmon linewidth, enabling monochromatic coloration and significantly enhancing the far-field scattering intensity of the individual nanorod elements. The bright coloration can be observed with p-polarized white light excitation, consistent with the use of this approach in display devices. The resulting color pixels are constructed with a simple design, are compatible with scalable fabrication methods, and provide contrast ratios exceeding 100:1. PMID:25225385

  12. Active Pixel Sensors: Are CCD's Dinosaurs?

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.

    1993-01-01

    Charge-coupled devices (CCD's) are presently the technology of choice for most imaging applications. In the 23 years since their invention in 1970, they have evolved to a sophisticated level of performance. However, as with all technologies, we can be certain that they will be supplanted someday. In this paper, the Active Pixel Sensor (APS) technology is explored as a possible successor to the CCD. An active pixel is defined as a detector array technology that has at least one active transistor within the pixel unit cell. The APS eliminates the need for nearly perfect charge transfer -- the Achilles' heel of CCDs. This perfect charge transfer makes CCD's radiation 'soft,' difficult to use under low light conditions, difficult to manufacture in large array sizes, difficult to integrate with on-chip electronics, difficult to use at low temperatures, difficult to use at high frame rates, and difficult to manufacture in non-silicon materials that extend wavelength response.

  13. Development of a CMOS SOI Pixel Detector

    SciTech Connect

    Arai, Y.; Hazumi, M.; Ikegami, Y.; Kohriki, T.; Tajima, O.; Terada, S.; Tsuboyama, T.; Unno, Y.; Ushiroda, Y.; Ikeda, H.; Hara, K.; Ishino, H.; Kawasaki, T.; Miyake, H.; Martin, E.; Varner, G.; Tajima, H.; Ohno, M.; Fukuda, K.; Komatsubara, H.; Ida, J.; /NONE - OKI ELECTR INDUST TOKYO

    2008-08-19

    We have developed a monolithic radiation pixel detector using silicon on insulator (SOI) with a commercial 0.15 {micro}m fully-depleted-SOI technology and a Czochralski high resistivity silicon substrate in place of a handle wafer. The SOI TEG (Test Element Group) chips with a size of 2.5 x 2.5 mm{sup 2} consisting of 20 x 20 {micro}m{sup 2} pixels have been designed and manufactured. Performance tests with a laser light illumination and a {beta} ray radioactive source indicate successful operation of the detector. We also briefly discuss the back gate effect as well as the simulation study.

  14. Commissioning of the ATLAS pixel detector

    SciTech Connect

    ATLAS Collaboration; Golling, Tobias

    2008-09-01

    The ATLAS pixel detector is a high precision silicon tracking device located closest to the LHC interaction point. It belongs to the first generation of its kind in a hadron collider experiment. It will provide crucial pattern recognition information and will largely determine the ability of ATLAS to precisely track particle trajectories and find secondary vertices. It was the last detector to be installed in ATLAS in June 2007, has been fully connected and tested in-situ during spring and summer 2008, and is ready for the imminent LHC turn-on. The highlights of the past and future commissioning activities of the ATLAS pixel system are presented.

  15. Diagnosis of abnormal biliary copper excretion by positron emission tomography with targeting of (64)Copper-asialofetuin complex in LEC rat model of Wilson's disease.

    PubMed

    Bahde, Ralf; Kapoor, Sorabh; Bhargava, Kuldeep K; Palestro, Christopher J; Gupta, Sanjeev

    2014-01-01

    Identification by molecular imaging of key processes in handling of transition state metals, such as copper (Cu), will be of considerable clinical value. For instance, the ability to diagnose Wilson's disease with molecular imaging by identifying copper excretion in an ATP7B-dependent manner will be very significant. To develop highly effective diagnostic approaches, we hypothesized that targeting of radiocopper via the asialoglycoprotein receptor will be appropriate for positron emission tomography, and examined this approach in a rat model of Wilson's disease. After complexing (64)Cu to asialofetuin we studied handling of this complex compared with (64)Cu in healthy LEA rats and diseased homozygous LEC rats lacking ATP7B and exhibiting hepatic copper toxicosis. We analyzed radiotracer clearance from blood, organ uptake, and biliary excretion, including sixty minute dynamic positron emission tomography recordings. In LEA rats, (64)Cu-asialofetuin was better cleared from blood followed by liver uptake and greater biliary excretion than (64)Cu. In LEC rats, (64)Cu-asialofetuin activity cleared even more rapidly from blood followed by greater uptake in liver, but neither (64)Cu-asialofetuin nor (64)Cu appeared in bile. Image analysis demonstrated rapid visualization of liver after (64)Cu-asialofetuin administration followed by decreased liver activity in LEA rats while liver activity progressively increased in LEC rats. Image analysis resolved this difference in hepatic activity within one hour. We concluded that (64)Cu-asialofetuin complex was successfully targeted to the liver and radiocopper was then excreted into bile in an ATP7B-dependent manner. Therefore, hepatic targeting of radiocopper will be appropriate for improving molecular diagnosis and for developing drug/cell/gene therapies in Wilson's disease.

  16. Diagnosis of abnormal biliary copper excretion by positron emission tomography with targeting of 64Copper-asialofetuin complex in LEC rat model of Wilson’s disease

    PubMed Central

    Bahde, Ralf; Kapoor, Sorabh; Bhargava, Kuldeep K; Palestro, Christopher J; Gupta, Sanjeev

    2014-01-01

    Identification by molecular imaging of key processes in handling of transition state metals, such as copper (Cu), will be of considerable clinical value. For instance, the ability to diagnose Wilson’s disease with molecular imaging by identifying copper excretion in an ATP7B-dependent manner will be very significant. To develop highly effective diagnostic approaches, we hypothesized that targeting of radiocopper via the asialoglycoprotein receptor will be appropriate for positron emission tomography, and examined this approach in a rat model of Wilson’s disease. After complexing 64Cu to asialofetuin we studied handling of this complex compared with 64Cu in healthy LEA rats and diseased homozygous LEC rats lacking ATP7B and exhibiting hepatic copper toxicosis. We analyzed radiotracer clearance from blood, organ uptake, and biliary excretion, including sixty minute dynamic positron emission tomography recordings. In LEA rats, 64Cu-asialofetuin was better cleared from blood followed by liver uptake and greater biliary excretion than 64Cu. In LEC rats, 64Cu-asialofetuin activity cleared even more rapidly from blood followed by greater uptake in liver, but neither 64Cu-asialofetuin nor 64Cu appeared in bile. Image analysis demonstrated rapid visualization of liver after 64Cu-asialofetuin administration followed by decreased liver activity in LEA rats while liver activity progressively increased in LEC rats. Image analysis resolved this difference in hepatic activity within one hour. We concluded that 64Cu-asialofetuin complex was successfully targeted to the liver and radiocopper was then excreted into bile in an ATP7B-dependent manner. Therefore, hepatic targeting of radiocopper will be appropriate for improving molecular diagnosis and for developing drug/cell/gene therapies in Wilson’s disease. PMID:25250203

  17. From hybrid to CMOS pixels ... a possibility for LHC's pixel future?

    NASA Astrophysics Data System (ADS)

    Wermes, N.

    2015-12-01

    Hybrid pixel detectors have been invented for the LHC to make tracking and vertexing possible at all in LHC's radiation intense environment. The LHC pixel detectors have meanwhile very successfully fulfilled their promises and R&D for the planned HL-LHC upgrade is in full swing, targeting even higher ionising doses and non-ionising fluences. In terms of rate and radiation tolerance hybrid pixels are unrivaled. But they have disadvantages as well, most notably material thickness, production complexity, and cost. Meanwhile also active pixel sensors (DEPFET, MAPS) have become real pixel detectors but they would by far not stand the rates and radiation faced from HL-LHC. New MAPS developments, so-called DMAPS (depleted MAPS) which are full CMOS-pixel structures with charge collection in a depleted region have come in the R&D focus for pixels at high rate/radiation levels. This goal can perhaps be realised exploiting HV technologies, high ohmic substrates and/or SOI based technologies. The paper covers the main ideas and some encouraging results from prototyping R&D, not hiding the difficulties.

  18. Uncooled infrared detectors toward smaller pixel pitch with newly proposed pixel structure

    NASA Astrophysics Data System (ADS)

    Tohyama, Shigeru; Sasaki, Tokuhito; Endoh, Tsutomu; Sano, Masahiko; Kato, Koji; Kurashina, Seiji; Miyoshi, Masaru; Yamazaki, Takao; Ueno, Munetaka; Katayama, Haruyoshi; Imai, Tadashi

    2013-12-01

    An uncooled infrared (IR) focal plane array (FPA) with 23.5 μm pixel pitch has been successfully demonstrated and has found wide commercial applications in the areas of thermography, security cameras, and other applications. One of the key issues for uncooled IRFPA technology is to shrink the pixel pitch because the size of the pixel pitch determines the overall size of the FPA, which, in turn, determines the cost of the IR camera products. This paper proposes an innovative pixel structure with a diaphragm and beams placed in different levels to realize an uncooled IRFPA with smaller pixel pitch (≦17 μm). The upper level consists of a diaphragm with VOx bolometer and IR absorber layers, while the lower level consists of the two beams, which are designed to be placed on the adjacent pixels. The test devices of this pixel design with 12, 15, and 17 μm pitch have been fabricated on the Si read-out integrated circuit (ROIC) of quarter video graphics array (QVGA) (320×240) with 23.5 μm pitch. Their performances are nearly equal to those of the IRFPA with 23.5 μm pitch. For example, a noise equivalent temperature difference of 12 μm pixel is 63.1 mK for F/1 optics with the thermal time constant of 14.5 ms. Then, the proposed structure is shown to be effective for the existing IRFPA with 23.5 μm pitch because of the improvements in IR sensitivity. Furthermore, the advanced pixel structure that has the beams composed of two levels are demonstrated to be realizable.

  19. STIS CCD Hot Pixel Annealing Cycle 11

    NASA Astrophysics Data System (ADS)

    Proffitt, Charles

    2002-07-01

    The effectiveness of the CCD hot pixel annealing process is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects. In addition CTE performance is examined by looking for traps in a low signal level flat. Follows on from proposal 8906.

  20. STIS CCD Hot Pixel Annealing Cycle 12

    NASA Astrophysics Data System (ADS)

    Maiz Apellaniz, Jesus

    2003-07-01

    The effectiveness of the CCD hot pixel annealing process is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects. In addition CTE performance is examined by looking for traps in a low signal level flat. Follows on from proposal 9612.

  1. Digital-pixel focal plane array development

    NASA Astrophysics Data System (ADS)

    Brown, Matthew G.; Baker, Justin; Colonero, Curtis; Costa, Joe; Gardner, Tom; Kelly, Mike; Schultz, Ken; Tyrrell, Brian; Wey, Jim

    2010-01-01

    Since 2006, MIT Lincoln Laboratory has been developing Digital-pixel Focal Plane Array (DFPA) readout integrated circuits (ROICs). To date, four 256 × 256 30 μm pitch DFPA designs with in-pixel analog to digital conversion have been fabricated using IBM 90 nm CMOS processes. The DFPA ROICs are compatible with a wide range of detector materials and cutoff wavelengths; HgCdTe, QWIP, and InGaAs photo-detectors with cutoff wavelengths ranging from 1.6 to 14.5 μm have been hybridized to the same digital-pixel readout. The digital-pixel readout architecture offers high dynamic range, A/C or D/C coupled integration, and on-chip image processing with low power orthogonal transfer operations. The newest ROIC designs support two-color operation with a single Indium bump connection. Development and characterization of the two-color DFPA designs is presented along with applications for this new digital readout technology.

  2. Adaptive bad pixel correction algorithm for IRFPA based on PCNN

    NASA Astrophysics Data System (ADS)

    Leng, Hanbing; Zhou, Zuofeng; Cao, Jianzhong; Yi, Bo; Yan, Aqi; Zhang, Jian

    2013-10-01

    Bad pixels and response non-uniformity are the primary obstacles when IRFPA is used in different thermal imaging systems. The bad pixels of IRFPA include fixed bad pixels and random bad pixels. The former is caused by material or manufacture defect and their positions are always fixed, the latter is caused by temperature drift and their positions are always changing. Traditional radiometric calibration-based bad pixel detection and compensation algorithm is only valid to the fixed bad pixels. Scene-based bad pixel correction algorithm is the effective way to eliminate these two kinds of bad pixels. Currently, the most used scene-based bad pixel correction algorithm is based on adaptive median filter (AMF). In this algorithm, bad pixels are regarded as image noise and then be replaced by filtered value. However, missed correction and false correction often happens when AMF is used to handle complex infrared scenes. To solve this problem, a new adaptive bad pixel correction algorithm based on pulse coupled neural networks (PCNN) is proposed. Potential bad pixels are detected by PCNN in the first step, then image sequences are used periodically to confirm the real bad pixels and exclude the false one, finally bad pixels are replaced by the filtered result. With the real infrared images obtained from a camera, the experiment results show the effectiveness of the proposed algorithm.

  3. Design Methodology: ASICs with complex in-pixel processing for Pixel Detectors

    SciTech Connect

    Fahim, Farah

    2014-10-31

    The development of Application Specific Integrated Circuits (ASIC) for pixel detectors with complex in-pixel processing using Computer Aided Design (CAD) tools that are, themselves, mainly developed for the design of conventional digital circuits requires a specialized approach. Mixed signal pixels often require parasitically aware detailed analog front-ends and extremely compact digital back-ends with more than 1000 transistors in small areas below 100μm x 100μm. These pixels are tiled to create large arrays, which have the same clock distribution and data readout speed constraints as in, for example, micro-processors. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout.

  4. Design methodology: edgeless 3D ASICs with complex in-pixel processing for pixel detectors

    SciTech Connect

    Fahim Farah, Fahim Farah; Deptuch, Grzegorz W.; Hoff, James R.; Mohseni, Hooman

    2015-08-28

    The design methodology for the development of 3D integrated edgeless pixel detectors with in-pixel processing using Electronic Design Automation (EDA) tools is presented. A large area 3 tier 3D detector with one sensor layer and two ASIC layers containing one analog and one digital tier, is built for x-ray photon time of arrival measurement and imaging. A full custom analog pixel is 65μm x 65μm. It is connected to a sensor pixel of the same size on one side, and on the other side it has approximately 40 connections to the digital pixel. A 32 x 32 edgeless array without any peripheral functional blocks constitutes a sub-chip. The sub-chip is an indivisible unit, which is further arranged in a 6 x 6 array to create the entire 1.248cm x 1.248cm ASIC. Each chip has 720 bump-bond I/O connections, on the back of the digital tier to the ceramic PCB. All the analog tier power and biasing is conveyed through the digital tier from the PCB. The assembly has no peripheral functional blocks, and hence the active area extends to the edge of the detector. This was achieved by using a few flavors of almost identical analog pixels (minimal variation in layout) to allow for peripheral biasing blocks to be placed within pixels. The 1024 pixels within a digital sub-chip array have a variety of full custom, semi-custom and automated timing driven functional blocks placed together. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout. The methodology uses the Cadence design platform, however it is not limited to this tool.

  5. Crystal structure of MytiLec, a galactose-binding lectin from the mussel Mytilus galloprovincialis with cytotoxicity against certain cancer cell types.

    PubMed

    Terada, Daiki; Kawai, Fumihiro; Noguchi, Hiroki; Unzai, Satoru; Hasan, Imtiaj; Fujii, Yuki; Park, Sam-Yong; Ozeki, Yasuhiro; Tame, Jeremy R H

    2016-01-01

    MytiLec is a lectin, isolated from bivalves, with cytotoxic activity against cancer cell lines that express globotriaosyl ceramide, Galα(1,4)Galβ(1,4)Glcα1-Cer, on the cell surface. Functional analysis shows that the protein binds to the disaccharide melibiose, Galα(1,6)Glc, and the trisaccharide globotriose, Galα(1,4)Galβ(1,4)Glc. Recombinant MytiLec expressed in bacteria showed the same haemagglutinating and cytotoxic activity against Burkitt's lymphoma (Raji) cells as the native form. The crystal structure has been determined to atomic resolution, in the presence and absence of ligands, showing the protein to be a member of the β-trefoil family, but with a mode of ligand binding unique to a small group of related trefoil lectins. Each of the three pseudo-equivalent binding sites within the monomer shows ligand binding, and the protein forms a tight dimer in solution. An engineered monomer mutant lost all cytotoxic activity against Raji cells, but retained some haemagglutination activity, showing that the quaternary structure of the protein is important for its cellular effects. PMID:27321048

  6. Crystal structure of MytiLec, a galactose-binding lectin from the mussel Mytilus galloprovincialis with cytotoxicity against certain cancer cell types

    PubMed Central

    Terada, Daiki; Kawai, Fumihiro; Noguchi, Hiroki; Unzai, Satoru; Hasan, Imtiaj; Fujii, Yuki; Park, Sam-Yong; Ozeki, Yasuhiro; Tame, Jeremy R. H.

    2016-01-01

    MytiLec is a lectin, isolated from bivalves, with cytotoxic activity against cancer cell lines that express globotriaosyl ceramide, Galα(1,4)Galβ(1,4)Glcα1-Cer, on the cell surface. Functional analysis shows that the protein binds to the disaccharide melibiose, Galα(1,6)Glc, and the trisaccharide globotriose, Galα(1,4)Galβ(1,4)Glc. Recombinant MytiLec expressed in bacteria showed the same haemagglutinating and cytotoxic activity against Burkitt’s lymphoma (Raji) cells as the native form. The crystal structure has been determined to atomic resolution, in the presence and absence of ligands, showing the protein to be a member of the β-trefoil family, but with a mode of ligand binding unique to a small group of related trefoil lectins. Each of the three pseudo-equivalent binding sites within the monomer shows ligand binding, and the protein forms a tight dimer in solution. An engineered monomer mutant lost all cytotoxic activity against Raji cells, but retained some haemagglutination activity, showing that the quaternary structure of the protein is important for its cellular effects. PMID:27321048

  7. Proteomic analysis of the hepatic tissue of Long-Evans Cinnamon (LEC) rats according to the natural course of Wilson disease.

    PubMed

    Lee, Beom H; Kim, Jae-Min; Heo, Sun H; Mun, Joo H; Kim, Jihun; Kim, Joo H; Jin, Hye Y; Kim, Gu-Hwan; Choi, Jin-Ho; Yoo, Han-Wook

    2011-09-01

    Copper-induced toxicity is important in the pathogenic process of Wilson's disease (WD). Using Long-Evans Cinnamon (LEC) rats, an animal model of WD, the study was undertaken to identify proteins involved in the process of WD and to investigate their functional roles in copper-induced hepatotoxicity. In early stages, expression levels of mitochondrial matrix proteins including agmatinase, isovaleryl coenzyme A dehydrogenase, and cytochrome b5 were downregulated. As mitochondrial injuries progressed, along with subsequent apoptotic processes, expressions of malate dehydrogenase 1, annexin A5, transferrin, S-adenosylhomocysteine hydrolase, and sulfite oxidase 1 were differentially regulated. Notably, the expression of malate dehydrogenase 1 was downregulated while the annexin A5 was overexpressed in an age-dependent manner, indicating that these proteins may be involved in the WD process. In addition, pronounced under-expression of S-adenosylhomocysteine hydrolase in elderly LEC rats, also involved in monoamine neurotransmitter metabolism, indicates that this protein might be related to the development of neurological manifestations in WD. The results of our study help to understand the pathogenic process of WD in hepatic tissues, identifying the important proteins associated with the disease process of WD, and to investigate the molecular pathogenic process underlying the development of neurological manifestations in WD.

  8. Impact of CT detector pixel-to-pixel crosstalk on image quality

    NASA Astrophysics Data System (ADS)

    Engel, Klaus J.; Spies, Lothar; Vogtmeier, Gereon; Luhta, Randy

    2006-03-01

    In Computed Tomography (CT), the image quality sensitively depends on the accuracy of the X-ray projection signal, which is acquired by a two-dimensional array of pixel cells in the detector. If the signal of X-ray photons is spread out to neighboring pixels (crosstalk), a decrease of spatial resolution may result. Moreover, streak and ring artifacts may emerge. Deploying system simulations for state-of-the-art CT detector configurations, we characterize origin and appearance of these artifacts in the reconstructed CT images for different scenarios. A uniform pixel-to-pixel crosstalk results in a loss of spatial resolution only. The Modulation Transfer Function (MTF) is attenuated, without affecting the limiting resolution, which is defined as the first zero of the MTF. Additional streak and ring artifacts appear, if the pixel-to-pixel crosstalk is non-uniform. Parallel to the system simulations we developed an analytical model. The model explains resolution loss and artifact level using the first and second derivative of the X-ray profile acquired by the detector. Simulations and analytical model are in agreement to each other. We discuss the perceptibility of ring and streak artifacts within noisy images if no crosstalk correction is applied.

  9. Empirical formula for rates of hot pixel defects based on pixel size, sensor area, and ISO

    NASA Astrophysics Data System (ADS)

    Chapman, Glenn H.; Thomas, Rohit; Koren, Zahava; Koren, Israel

    2013-02-01

    Experimentally, image sensors measurements show a continuous development of in-field permanent hot pixel defects increasing in numbers over time. In our tests we accumulated data on defects in cameras ranging from large area (<300 sq mm) DSLR's, medium sized (~40 sq mm) point and shoot, and small (20 sq mm) cell phone cameras. The results show that the rate of defects depends on the technology (APS or CCD), and on design parameters like imager area, pixel size (from 1.5 to 7 um), and gain (from ISO100 to 1600). Comparing different sensor sizes with similar pixel sizes has shown that defect rates scale linearly with sensor area, suggesting the metric of defects/year/sq mm, which we call defect density. A search was made to model this defect density as a function of the two parameters pixel size and ISO. The best empirical fit was obtained by a power law curve. For CCD imagers, the defect densities are proportional to the pixel size to the power of -2.25 times the ISO to the power of 0.69. For APS (CMOS) sensors the power law had the defect densities proportional to the pixel size to the power of -3.07 times the ISO raised to the power of 0.5. Extending our empirical formula to include ISO allows us to predict the expected defect development rate for a wide set of sensor parameters.

  10. ACS/WFC Pixel Stability - Bringing the Pixels Back to the Science

    NASA Astrophysics Data System (ADS)

    Borncamp, David; Grogin, Norman A.; Bourque, Matthew; Ogaz, Sara

    2016-06-01

    Electrical current that has been trapped within the lattice structure of a Charged Coupled Device (CCD) can be present through multiple exposures, which will have an adverse effect on its science performance. The traditional way to correct for this extra charge is to take an image with the camera shutter closed periodically throughout the lifetime of the instrument. These images, generally referred to as dark images, allow for the characterization of the extra charge that is trapped within the CCD at the time of observation. This extra current can then be subtracted out of science images to correct for the extra charge that was there at this time. Pixels that have a charge above a certain threshold of current are marked as “hot” and flagged in the data quality array. However, these pixels may not be "bad" in the traditional sense that they cannot be reliably dark-subtracted. If these pixels are shown to be stable over an anneal period, the charge can be properly subtracted and the extra noise from this dark current can be taken into account. We present the results of a pixel history study that analyzes every pixel of ACS/WFC individually and allows pixels that were marked as bad to be brought back into the science image.

  11. X-Ray induced cataract is preceded by LEC loss, and coincident with accumulation of cortical DNA, and ROS; similarities with age-related cataracts

    PubMed Central

    Zitnik, Galynn; Tsai, Ryan; Wolf, Norman

    2010-01-01

    Purpose To compare age-related cataractous (ARC) changes in unirradiated mice lenses to those induced by head-only X-irradiation of 3 month-old mice. Methods lens epithelial cells (LECs) as well as partially degraded cortical DNA were visualized in fixed sections using 4',6-diamidino-2-phenylindole (DAPI) staining, and in fresh lenses using the vital stain Hoechst 33342. reactive oxygen species (ROS) activity was also visualized directly in fresh lenses using the vital dye Dihydrorhodamine (DHR). In fixed lenses an antibody specific for 8-OH Guanosine (8-OH-G) lesions was used to visualize DNA oxidative adducts from ROS damage. Alpha smooth muscle actin was visualized using specific antibodies to determine if myofibroblasts were present. Fluorescence was quantified using Laser Scanning Confocal Microscopy (LSCM). The degree of lens opacity and cataract formation was determined by slit lamp, or from digitalized images of light reflections taken with a low magnification light microscope. Results Using DNA- and ROS-specific vital fluorescent dyes, and laser scanning confocal microscopy we have previously described 4 changes in the aging rodent lenses: 1) a significantly decreased density of surface LECs in lenses from old compared to younger mice and rats; 2) a very large increase in retained cortical nuclei and DNA fragments in the secondary lens fibers of old rodent lenses; 3) increased cortical ROS in old rodent lenses; 4) increased cataract concomitantly with the cortical DNA and ROS increases. In the current study we report that these same 4 changes also occur in an accelerated fashion in mice given head-only X-irradiation at 3 months of age. In addition to vital staining of fresh lenses, we also examined sections from fixed eyes stained with DAPI or hematoxylin and eosin (H&E) and found the same loss of surface LECs and accumulation of undigested nuclei and debris in secondary lens fibers occur with age or following X-irradiation. In addition sections from fixed

  12. Advanced monolithic pixel sensors using SOI technology

    NASA Astrophysics Data System (ADS)

    Miyoshi, Toshinobu; Arai, Yasuo; Asano, Mari; Fujita, Yowichi; Hamasaki, Ryutaro; Hara, Kazuhiko; Honda, Shunsuke; Ikegami, Yoichi; Kurachi, Ikuo; Mitsui, Shingo; Nishimura, Ryutaro; Tauchi, Kazuya; Tobita, Naoshi; Tsuboyama, Toru; Yamada, Miho

    2016-07-01

    We are developing advanced pixel sensors using silicon-on-insulator (SOI) technology. A SOI wafer is used; top silicon is used for electric circuit and bottom silicon is used as a sensor. Target applications are high-energy physics, X-ray astronomy, material science, non-destructive inspection, medical application and so on. We have developed two integration-type pixel sensors, FPIXb and INTPIX7. These sensors were processed on single SOI wafers with various substrates in n- or p-type and double SOI wafers. The development status of double SOI sensors and some up-to-date test results of n-type and p-type SOI sensors are shown.

  13. The Belle II DEPFET pixel detector

    NASA Astrophysics Data System (ADS)

    Moser, Hans-Günther

    2016-09-01

    The Belle II experiment at KEK (Tsukuba, Japan) will explore heavy flavour physics (B, charm and tau) at the starting of 2018 with unprecedented precision. Charged particles are tracked by a two-layer DEPFET pixel device (PXD), a four-layer silicon strip detector (SVD) and the central drift chamber (CDC). The PXD will consist of two layers at radii of 14 mm and 22 mm with 8 and 12 ladders, respectively. The pixel sizes will vary, between 50 μm×(55-60) μm in the first layer and between 50 μm×(70-85) μm in the second layer, to optimize the charge sharing efficiency. These innermost layers have to cope with high background occupancy, high radiation and must have minimal material to reduce multiple scattering. These challenges are met using the DEPFET technology. Each pixel is a FET integrated on a fully depleted silicon bulk. The signal charge collected in the 'internal gate' modulates the FET current resulting in a first stage amplification and therefore very low noise. This allows very thin sensors (75 μm) reducing the overall material budget of the detector (0.21% X0). Four fold multiplexing of the column parallel readout allows read out a full frame of the pixel matrix in only 20 μs while keeping the power consumption low enough for air cooling. Only the active electronics outside the detector acceptance has to be cooled actively with a two phase CO2 system. Furthermore the DEPFET technology offers the unique feature of an electronic shutter which allows the detector to operate efficiently in the continuous injection mode of superKEKB.

  14. Active-Pixel Cosmic-Ray Sensor

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.; Cunningham, Thomas J.; Holtzman, Melinda J.

    1994-01-01

    Cosmic-ray sensor comprises planar rectangular array of lateral bipolar npn floating-base transistors each of which defines pixel. Collector contacts of all transistors in each row connected to same X (column) line conductor; emitter contacts of all transistors in each column connected to same Y (row) line conductor; and current in each row and column line sensed by amplifier, output of which fed to signal-processing circuits.

  15. The Silicon Pixel Detector for ALICE Experiment

    SciTech Connect

    Fabris, D.; Bombonati, C.; Dima, R.; Lunardon, M.; Moretto, S.; Pepato, A.; Bohus, L. Sajo; Scarlassara, F.; Segato, G.; Shen, D.; Turrisi, R.; Viesti, G.; Anelli, G.; Boccardi, A.; Burns, M.; Campbell, M.; Ceresa, S.; Conrad, J.; Kluge, A.; Kral, M.

    2007-10-26

    The Inner Tracking System (ITS) of the ALICE experiment is made of position sensitive detectors which have to operate in a region where the track density may be as high as 50 tracks/cm{sup 2}. To handle such densities detectors with high precision and granularity are mandatory. The Silicon Pixel Detector (SPD), the innermost part of the ITS, has been designed to provide tracking information close to primary interaction point. The assembly of the entire SPD has been completed.

  16. CMOS Active Pixel Sensor Technology and Reliability Characterization Methodology

    NASA Technical Reports Server (NTRS)

    Chen, Yuan; Guertin, Steven M.; Pain, Bedabrata; Kayaii, Sammy

    2006-01-01

    This paper describes the technology, design features and reliability characterization methodology of a CMOS Active Pixel Sensor. Both overall chip reliability and pixel reliability are projected for the imagers.

  17. Status of the CMS pixel project

    SciTech Connect

    Uplegger, Lorenzo; /Fermilab

    2008-01-01

    The Compact Muon Solenoid Experiment (CMS) will start taking data at the Large Hadron Collider (LHC) in 2008. The closest detector to the interaction point is the silicon pixel detector which is the heart of the tracking system. It consists of three barrel layers and two pixel disks on each side of the interaction point for a total of 66 million channels. Its proximity to the interaction point means there will be very large particle fluences and therefore a radiation-tolerant design is necessary. The pixel detector will be crucial to achieve a good vertex resolution and will play a key role in pattern recognition and track reconstruction. The results from test beam runs prove that the expected performances can be achieved. The detector is currently being assembled and will be ready for insertion into CMS in early 2008. During the assembly phase, a thorough electronic test is being done to check the functionality of each channel to guarantee the performance required to achieve the physics goals. This report will present the final detector design, the status of the production as well as results from test beam runs to validate the expected performance.

  18. Soil moisture variability within remote sensing pixels

    SciTech Connect

    Charpentier, M.A.; Groffman, P.M. )

    1992-11-30

    This work is part of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), an international land-surface-atmosphere experiment aimed at improving the way climate models represent energy, water, heat, and carbon exchanges, and improving the utilization of satellite based remote sensing to monitor such parameters. This paper addresses the question of soil moisture variation within the field of view of a remote sensing pixel. Remote sensing is the only practical way to sense soil moisture over large areas, but it is known that there can be large variations of soil moisture within the field of view of a pixel. The difficulty with this is that many processes, such as gas exchange between surface and atmosphere can vary dramatically with moisture content, and a small wet spot, for example, can have a dramatic impact on such processes, and thereby bias remote sensing data results. Here the authors looked at the impact of surface topography on the level of soil moisture, and the interaction of both on the variability of soil moisture sensed by a push broom microwave radiometer (PBMR). In addition the authors looked at the question of whether variations of soil moisture within pixel size areas could be used to assign errors to PBMR generated soil moisture data.

  19. Photovoltaic retinal prosthesis with high pixel density

    NASA Astrophysics Data System (ADS)

    Mathieson, Keith; Loudin, James; Goetz, Georges; Huie, Philip; Wang, Lele; Kamins, Theodore I.; Galambos, Ludwig; Smith, Richard; Harris, James S.; Sher, Alexander; Palanker, Daniel

    2012-06-01

    Retinal degenerative diseases lead to blindness due to loss of the `image capturing' photoreceptors, while neurons in the `image-processing' inner retinal layers are relatively well preserved. Electronic retinal prostheses seek to restore sight by electrically stimulating the surviving neurons. Most implants are powered through inductive coils, requiring complex surgical methods to implant the coil-decoder-cable-array systems that deliver energy to stimulating electrodes via intraocular cables. We present a photovoltaic subretinal prosthesis, in which silicon photodiodes in each pixel receive power and data directly through pulsed near-infrared illumination and electrically stimulate neurons. Stimulation is produced in normal and degenerate rat retinas, with pulse durations of 0.5-4 ms, and threshold peak irradiances of 0.2-10 mW mm-2, two orders of magnitude below the ocular safety limit. Neural responses were elicited by illuminating a single 70 µm bipolar pixel, demonstrating the possibility of a fully integrated photovoltaic retinal prosthesis with high pixel density.

  20. Photovoltaic Retinal Prosthesis with High Pixel Density.

    PubMed

    Mathieson, Keith; Loudin, James; Goetz, Georges; Huie, Philip; Wang, Lele; Kamins, Theodore I; Galambos, Ludwig; Smith, Richard; Harris, James S; Sher, Alexander; Palanker, Daniel

    2012-06-01

    Retinal degenerative diseases lead to blindness due to loss of the "image capturing" photoreceptors, while neurons in the "image processing" inner retinal layers are relatively well preserved. Electronic retinal prostheses seek to restore sight by electrically stimulating surviving neurons. Most implants are powered through inductive coils, requiring complex surgical methods to implant the coil-decoder-cable-array systems, which deliver energy to stimulating electrodes via intraocular cables. We present a photovoltaic subretinal prosthesis, in which silicon photodiodes in each pixel receive power and data directly through pulsed near-infrared illumination and electrically stimulate neurons. Stimulation was produced in normal and degenerate rat retinas, with pulse durations from 0.5 to 4 ms, and threshold peak irradiances from 0.2 to 10 mW/mm(2), two orders of magnitude below the ocular safety limit. Neural responses were elicited by illuminating a single 70 μm bipolar pixel, demonstrating the possibility of a fully-integrated photovoltaic retinal prosthesis with high pixel density.

  1. Development of silicon micropattern pixel detectors

    NASA Astrophysics Data System (ADS)

    Heijne, E. H. M.; Antinori, F.; Beker, H.; Batignani, G.; Beusch, W.; Bonvicini, V.; Bosisio, L.; Boutonnet, C.; Burger, P.; Campbell, M.; Cantoni, P.; Catanesi, M. G.; Chesi, E.; Claeys, C.; Clemens, J. C.; Cohen Solal, M.; Darbo, G.; Da Via, C.; Debusschere, I.; Delpierre, P.; Di Bari, D.; Di Liberto, S.; Dierickx, B.; Enz, C. C.; Focardi, E.; Forti, F.; Gally, Y.; Glaser, M.; Gys, T.; Habrard, M. C.; Hallewell, G.; Hermans, L.; Heuser, J.; Hurst, R.; Inzani, P.; Jæger, J. J.; Jarron, P.; Karttaavi, T.; Kersten, S.; Krummenacher, F.; Leitner, R.; Lemeilleur, F.; Lenti, V.; Letheren, M.; Lokajicek, M.; Loukas, D.; Macdermott, M.; Maggi, G.; Manzari, V.; Martinengo, P.; Meddeler, G.; Meddi, F.; Mekkaoui, A.; Menetrey, A.; Middelkamp, P.; Morando, M.; Munns, A.; Musico, P.; Nava, P.; Navach, F.; Neyer, C.; Pellegrini, F.; Pengg, F.; Perego, R.; Pindo, M.; Pospisil, S.; Potheau, R.; Quercigh, E.; Redaelli, N.; Ridky, J.; Rossi, L.; Sauvage, D.; Segato, G.; Simone, S.; Sopko, B.; Stefanini, G.; Strakos, V.; Tempesta, P.; Tonelli, G.; Vegni, G.; Verweij, H.; Viertel, G. M.; Vrba, V.; Waisbard, J.; CERN RD19 Collaboration

    1994-09-01

    Successive versions of high speed, active silicon pixel detectors with integrated readout electronics have been developed for particle physics experiments using monolithic and hybrid technologies. Various matrices with binary output as well as a linear detector with analog output have been made. The hybrid binary matrix with 1024 cells (dimension 75 μm×500 μm) can capture events at ˜5 MHz and a selected event can then be read out in < 10 μs. In different beam tests at CERN a precision of 25 μm has been achieved and the efficiency was better than 99.2%. Detector thicknesses of 300 μm and 150 μm of silicon have been used. In a test with a 109Cd source a noise level of 170 e - r.m.s. (1.4 keV fwhm) has been measured with a threshold non-uniformity of 750 e - r.m.s. Objectives of the development work are the increase of the size of detecting area without loss of efficiency, the design of an appropriate readout architecture for collider operation, the reduction of material thickness in the detector, understanding of the threshold non-uniformity, study of the sensitivity of the pixel matrices to light and low energy electrons for scintillating fiber detector readout and last but not least, the optimization of cost and yield of the pixel detectors in production.

  2. Photovoltaic Retinal Prosthesis with High Pixel Density

    PubMed Central

    Mathieson, Keith; Loudin, James; Goetz, Georges; Huie, Philip; Wang, Lele; Kamins, Theodore I.; Galambos, Ludwig; Smith, Richard; Harris, James S.; Sher, Alexander; Palanker, Daniel

    2012-01-01

    Retinal degenerative diseases lead to blindness due to loss of the “image capturing” photoreceptors, while neurons in the “image processing” inner retinal layers are relatively well preserved. Electronic retinal prostheses seek to restore sight by electrically stimulating surviving neurons. Most implants are powered through inductive coils, requiring complex surgical methods to implant the coil-decoder-cable-array systems, which deliver energy to stimulating electrodes via intraocular cables. We present a photovoltaic subretinal prosthesis, in which silicon photodiodes in each pixel receive power and data directly through pulsed near-infrared illumination and electrically stimulate neurons. Stimulation was produced in normal and degenerate rat retinas, with pulse durations from 0.5 to 4 ms, and threshold peak irradiances from 0.2 to 10 mW/mm2, two orders of magnitude below the ocular safety limit. Neural responses were elicited by illuminating a single 70 μm bipolar pixel, demonstrating the possibility of a fully-integrated photovoltaic retinal prosthesis with high pixel density. PMID:23049619

  3. A PFM based digital pixel with off-pixel residue measurement for 15μm pitch MWIR FPAs

    NASA Astrophysics Data System (ADS)

    Abbasi, Shahbaz; Shafique, Atia; Galioglu, Arman; Ceylan, Omer; Yazici, Melik; Gurbuz, Yasar

    2016-05-01

    Digital pixels based on pulse frequency modulation (PFM) employ counting techniques to achieve very high charge handling capability compared to their analog counterparts. Moreover, extended counting methods making use of leftover charge (residue) on the integration capacitor help improve the noise performance of these pixels. However, medium wave infrared (MWIR) focal plane arrays (FPAs) having smaller pixel pitch are constrained in terms of pixel area which makes it difficult to add extended counting circuitry to the pixel. Thus, this paper investigates the performance of digital pixels employing off-pixel residue measurement. A circuit prototype of such a pixel has been designed for 15μm pixel pitch and fabricated in 90nm CMOS. The prototype is composed of a pixel front-end based on a PFM loop. The frontend is a modified version of conventional design providing a means for buffering the signal that needs to be converted to a digital value by an off-pixel ADC. The pixel has an integration phase and a residue measurement phase. Measured integration performance of the pixel has been reported in this paper for various detector currents and integration times.

  4. PIXELS: Using field-based learning to investigate students' concepts of pixels and sense of scale

    NASA Astrophysics Data System (ADS)

    Pope, A.; Tinigin, L.; Petcovic, H. L.; Ormand, C. J.; LaDue, N.

    2015-12-01

    Empirical work over the past decade supports the notion that a high level of spatial thinking skill is critical to success in the geosciences. Spatial thinking incorporates a host of sub-skills such as mentally rotating an object, imagining the inside of a 3D object based on outside patterns, unfolding a landscape, and disembedding critical patterns from background noise. In this study, we focus on sense of scale, which refers to how an individual quantified space, and is thought to develop through kinesthetic experiences. Remote sensing data are increasingly being used for wide-reaching and high impact research. A sense of scale is critical to many areas of the geosciences, including understanding and interpreting remotely sensed imagery. In this exploratory study, students (N=17) attending the Juneau Icefield Research Program participated in a 3-hour exercise designed to study how a field-based activity might impact their sense of scale and their conceptions of pixels in remotely sensed imagery. Prior to the activity, students had an introductory remote sensing lecture and completed the Sense of Scale inventory. Students walked and/or skied the perimeter of several pixel types, including a 1 m square (representing a WorldView sensor's pixel), a 30 m square (a Landsat pixel) and a 500 m square (a MODIS pixel). The group took reflectance measurements using a field radiometer as they physically traced out the pixel. The exercise was repeated in two different areas, one with homogenous reflectance, and another with heterogeneous reflectance. After the exercise, students again completed the Sense of Scale instrument and a demographic survey. This presentation will share the effects and efficacy of the field-based intervention to teach remote sensing concepts and to investigate potential relationships between students' concepts of pixels and sense of scale.

  5. Detection and evaluation of mixed pixels in Landsat agricultural scenes

    NASA Technical Reports Server (NTRS)

    Merickel, M. B.; Lundgren, J. C.; Lennington, R. K.

    1982-01-01

    A major problem area encountered in the identification and estimation of agricultural crop proportions in Landsat imagery involves the large proportion of the pixels which are mixed pixels, whose spectral response is influenced by more than one ground cover type. The development of methods for the detection and estimation of crop proportions in mixed pixels is presently reported. The procedure designated CASCADE, based on the estimation of the gradient image for the detection of mixed pixels, considers the consequences of a linear mixing model and is found to provide a method for the allocation of mixed pixels to the surrounding homogeneous region.

  6. Active pixel sensor pixel having a photodetector whose output is coupled to an output transistor gate

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Nakamura, Junichi (Inventor); Kemeny, Sabrina E. (Inventor)

    2005-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node. There is also a readout circuit, part of which can be disposed at the bottom of each column of cells and be common to all the cells in the column. A Simple Floating Gate (SFG) pixel structure could also be employed in the imager to provide a non-destructive readout and smaller pixel sizes.

  7. How many pixels does it take to make a good 4"×6" print? Pixel count wars revisited

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    2011-01-01

    In the early 1980's the future of conventional silver-halide photographic systems was of great concern due to the potential introduction of electronic imaging systems then typified by the Sony Mavica analog electronic camera. The focus was on the quality of film-based systems as expressed in the number of equivalent number pixels and bits-per-pixel, and how many pixels would be required to create an equivalent quality image from a digital camera. It was found that 35-mm frames, for ISO 100 color negative film, contained equivalent pixels of 12 microns for a total of 18 million pixels per frame (6 million pixels per layer) with about 6 bits of information per pixel; the introduction of new emulsion technology, tabular AgX grains, increased the value to 8 bit per pixel. Higher ISO speed films had larger equivalent pixels, fewer pixels per frame, but retained the 8 bits per pixel. Further work found that a high quality 3.5" x 5.25" print could be obtained from a three layer system containing 1300 x 1950 pixels per layer or about 7.6 million pixels in all. In short, it became clear that when a digital camera contained about 6 million pixels (in a single layer using a color filter array and appropriate image processing) that digital systems would challenge and replace conventional film-based system for the consumer market. By 2005 this became the reality. Since 2005 there has been a "pixel war" raging amongst digital camera makers. The question arises about just how many pixels are required and are all pixels equal? This paper will provide a practical look at how many pixels are needed for a good print based on the form factor of the sensor (sensor size) and the effective optical modulation transfer function (optical spread function) of the camera lens. Is it better to have 16 million, 5.7-micron pixels or 6 million 7.8-micron pixels? How does intrinsic (no electronic boost) ISO speed and exposure latitude vary with pixel size? A systematic review of these issues will

  8. A new 9T global shutter pixel with CDS technique

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Ma, Cheng; Zhou, Quan; Wang, Xinyang

    2015-04-01

    Benefiting from motion blur free, Global shutter pixel is very widely used in the design of CMOS image sensors for high speed applications such as motion vision, scientifically inspection, etc. In global shutter sensors, all pixel signal information needs to be stored in the pixel first and then waiting for readout. For higher frame rate, we need very fast operation of the pixel array. There are basically two ways for the in pixel signal storage, one is in charge domain, such as the one shown in [1], this needs complicated process during the pixel fabrication. The other one is in voltage domain, one example is the one in [2], this pixel is based on the 4T PPD technology and normally the driving of the high capacitive transfer gate limits the speed of the array operation. In this paper we report a new 9T global shutter pixel based on 3-T partially pinned photodiode (PPPD) technology. It incorporates three in-pixel storage capacitors allowing for correlated double sampling (CDS) and pipeline operation of the array (pixel exposure during the readout of the array). Only two control pulses are needed for all the pixels at the end of exposure which allows high speed exposure control.

  9. Prototype pixel optohybrid for the CMS phase 1 upgraded pixel detector

    NASA Astrophysics Data System (ADS)

    Troska, J.; Detraz, S.; El Nasr-Storey, S. S.; Stejskal, P.; Sigaud, C.; Soos, C.; Vasey, F.

    2012-01-01

    The CMS Pixel detector phase 1 upgrade calls for an optical readout system operating digitally at or above 320 Mb/s. Since the re-use of the existing link components as installed is excluded, we have designed a new Pixel Optohybrid (POH) for use within this system. We report on the design and choice of components as well as their measured performance. In particular, we have studied the impact upon error-free link operation of the way the data are encoded before being transmitted over the link. We have thus demonstrated the feasibility of operating the new POH within the upgraded readout system.

  10. Active pixel sensor array with electronic shuttering

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor)

    2002-01-01

    An active pixel cell includes electronic shuttering capability. The cell can be shuttered to prevent additional charge accumulation. One mode transfers the current charge to a storage node that is blocked against accumulation of optical radiation. The charge is sampled from a floating node. Since the charge is stored, the node can be sampled at the beginning and the end of every cycle. Another aspect allows charge to spill out of the well whenever the charge amount gets higher than some amount, thereby providing anti blooming.

  11. Single-pixel complementary compressive sampling spectrometer

    NASA Astrophysics Data System (ADS)

    Lan, Ruo-Ming; Liu, Xue-Feng; Yao, Xu-Ri; Yu, Wen-Kai; Zhai, Guang-Jie

    2016-05-01

    A new type of compressive spectroscopy technique employing a complementary sampling strategy is reported. In a single sequence of spectral compressive sampling, positive and negative measurements are performed, in which sensing matrices with a complementary relationship are used. The restricted isometry property condition necessary for accurate recovery of compressive sampling theory is satisfied mathematically. Compared with the conventional single-pixel spectroscopy technique, the complementary compressive sampling strategy can achieve spectral recovery of considerably higher quality within a shorter sampling time. We also investigate the influence of the sampling ratio and integration time on the recovery quality.

  12. Small pixel uncooled imaging FPAs and applications

    NASA Astrophysics Data System (ADS)

    Blackwell, Richard; Franks, Glen; Lacroix, Daniel; Hyland, Sandra; Murphy, Robert

    2010-04-01

    BAE Systems continues to make dramatic progress in uncooled microbolometer sensors and applications. This paper will review the latest advancements in microbolometer technology at BAE Systems, including the development status of 17 micrometer pixel pitch detectors and imaging modules which are entering production and will be finding their way into BAE Systems products and applications. Benefits include increased die per wafer and potential benefits to SWAP for many applications. Applications include thermal weapons sights, thermal imaging modules for remote weapon stations, vehicle situational awareness sensors and mast/pole mounted sensors.

  13. Pixel-Level Simulation of Imaging Data

    NASA Astrophysics Data System (ADS)

    Stoughton, C.; Kuropatkin, N. P.; Neilsen, E., Jr.; Harms, D. C.

    2007-10-01

    We are preparing a set of Java packages to facilitate the design and operation of imaging surveys. The packages use shapelets to describe shapes of astronomical sources, optical distortions, and shear from weak gravitational lensing. We introduce noise, bad pixels, cosmic rays, the pupil image, saturation, and other observational effects. A set of utility classes handles I/O, plotting, and interfaces to existing packages: nom.tam.fits for FITS I/O; uk.ac.starlink.table for tables; and cern.colt for algorithms. The packages have been used to generate images for the Dark Energy Survey data challenges, and will be used by SNAP to continue evaluating its design.

  14. Raffinose, a plant galactoside, inhibits Pseudomonas aeruginosa biofilm formation via binding to LecA and decreasing cellular cyclic diguanylate levels.

    PubMed

    Kim, Han-Shin; Cha, Eunji; Kim, YunHye; Jeon, Young Ho; Olson, Betty H; Byun, Youngjoo; Park, Hee-Deung

    2016-01-01

    Biofilm formation on biotic or abiotic surfaces has unwanted consequences in medical, clinical, and industrial settings. Treatments with antibiotics or biocides are often ineffective in eradicating biofilms. Promising alternatives to conventional agents are biofilm-inhibiting compounds regulating biofilm development without toxicity to growth. Here, we screened a biofilm inhibitor, raffinose, derived from ginger. Raffinose, a galactotrisaccharide, showed efficient biofilm inhibition of Pseudomonas aeruginosa without impairing its growth. Raffinose also affected various phenotypes such as colony morphology, matrix formation, and swarming motility. Binding of raffinose to a carbohydrate-binding protein called LecA was the cause of biofilm inhibition and altered phenotypes. Furthermore, raffinose reduced the concentration of the second messenger, cyclic diguanylate (c-di-GMP), by increased activity of a c-di-GMP specific phosphodiesterase. The ability of raffinose to inhibit P. aeruginosa biofilm formation and its molecular mechanism opens new possibilities for pharmacological and industrial applications. PMID:27141909

  15. Raffinose, a plant galactoside, inhibits Pseudomonas aeruginosa biofilm formation via binding to LecA and decreasing cellular cyclic diguanylate levels

    PubMed Central

    Kim, Han-Shin; Cha, Eunji; Kim, YunHye; Jeon, Young Ho; Olson, Betty H.; Byun, Youngjoo; Park, Hee-Deung

    2016-01-01

    Biofilm formation on biotic or abiotic surfaces has unwanted consequences in medical, clinical, and industrial settings. Treatments with antibiotics or biocides are often ineffective in eradicating biofilms. Promising alternatives to conventional agents are biofilm-inhibiting compounds regulating biofilm development without toxicity to growth. Here, we screened a biofilm inhibitor, raffinose, derived from ginger. Raffinose, a galactotrisaccharide, showed efficient biofilm inhibition of Pseudomonas aeruginosa without impairing its growth. Raffinose also affected various phenotypes such as colony morphology, matrix formation, and swarming motility. Binding of raffinose to a carbohydrate-binding protein called LecA was the cause of biofilm inhibition and altered phenotypes. Furthermore, raffinose reduced the concentration of the second messenger, cyclic diguanylate (c-di-GMP), by increased activity of a c-di-GMP specific phosphodiesterase. The ability of raffinose to inhibit P. aeruginosa biofilm formation and its molecular mechanism opens new possibilities for pharmacological and industrial applications. PMID:27141909

  16. A new method to improve multiplication factor in micro-pixel avalanche photodiodes with high pixel density

    NASA Astrophysics Data System (ADS)

    Sadygov, Z.; Ahmadov, F.; Khorev, S.; Sadigov, A.; Suleymanov, S.; Madatov, R.; Mehdiyeva, R.; Zerrouk, F.

    2016-07-01

    Presented is a new model describing development of the avalanche process in time, taking into account the dynamics of electric field within the depleted region of the diode and the effect of parasitic capacitance shunting individual quenching micro-resistors on device parameters. Simulations show that the effective capacitance of a single pixel, which defines the multiplication factor, is the sum of the pixel capacitance and a parasitic capacitance shunting its quenching micro-resistor. Conclusions obtained as a result of modeling open possibilities of improving the pixel gain in micropixel avalanche photodiodes with high pixel density (or low pixel capacitance).

  17. Schottky junctions on semi-insulating LEC gallium arsenide for X- and {gamma}-ray spectrometers operated at and below room temperature

    SciTech Connect

    Bertuccio, G.; Pullia, A. |; Canali, C. |; Nava, F. |; Lanzieri

    1997-04-01

    This work deals with the study of a Schottky junction used as an X- and {gamma}-ray detector in a spectrometer operated in the temperature range from {minus}30 C to +22 C. The device, fabricated on liquid encapsulated Czochralski (LEC) semi-insulating Gallium Arsenide, is designed with a noninjecting ohmic contact which allows biasing voltages up to 550 V. At room temperature (22 C) the energy resolution is found to be relatively poor (15.5-keV full-width at half-maximum (FWHM) at 59.5 keV) due to the large junction reverse current, whose density is within the typical values for Schottky junctions on SI LEC GaAs. By cooling of the detector to {minus}30 C, the noise of the reverse current is drastically lowered, thus achieving electronic noise levels around 160--180 rms electrons. At 500-V bias, the {sup 241}Am spectrum has been resolved down to an energy of 4 keV with charge collection efficiency of cce = 97% and a resolution of about 2-keV FWHM for the Np L lines and 2.4-keV FWHM for the 59.5-keV {gamma} photons. The linearity of the detector has been measured to be better than {+-}0.6% within the explored energy range (14--59 keV). From the experimental spectra, it has been analyzed how either the electronic noise or the trapping of the signal charge contribute to the energy resolution of the spectrometer. The result is that despite the high measured cce, the trapping gives a contribution higher than 1.5 keV FWHM for the 59.5-keV spectral line. A comparison between the experimental results and Monte Carlo simulations, based on the Hecht model of charge trapping in detectors, is shown to give a satisfactory justification of the observed phenomena.

  18. Regioisomerism in cationic sulfonyl-substituted [Ir(C^N)2(N^N)](+) complexes: its influence on photophysical properties and LEC performance.

    PubMed

    Ertl, Cathrin D; Gil-Escrig, Lidón; Cerdá, Jesús; Pertegás, Antonio; Bolink, Henk J; Junquera-Hernández, José M; Prescimone, Alessandro; Neuburger, Markus; Constable, Edwin C; Ortí, Enrique; Housecroft, Catherine E

    2016-08-01

    A series of regioisomeric cationic iridium complexes of the type [Ir(C^N)2(bpy)][PF6] (bpy = 2,2'-bipyridine) is reported. The complexes contain 2-phenylpyridine-based cyclometallating ligands with a methylsulfonyl group in either the 3-, 4- or 5-position of the phenyl ring. All the complexes have been fully characterized, including their crystal structures. In acetonitrile solution, all the compounds are green emitters with emission maxima between 493 and 517 nm. Whereas substitution meta to the Ir-C bond leads to vibrationally structured emission profiles and photoluminescence quantum yields of 74 and 77%, placing a sulfone substituent in a para position results in a broad, featureless emission band, an enhanced quantum yield of 92% and a shorter excited-state lifetime. These results suggest a larger ligand-centred ((3)LC) character of the emissive triplet state in the case of meta substitution and a more pronounced charge transfer (CT) character in the case of para substitution. Going from solution to the solid state (powder samples and thin films), the emission maxima are red-shifted for all the complexes, resulting in green-yellow emission. Data obtained from electrochemical measurements and density functional theory calculations parallel the photophysical trends. Light-emitting electrochemical cells (LECs) based on the complexes were fabricated and evaluated. A maximum efficiency of 4.5 lm W(-1) at a maximum luminance of 940 cd m(-2) was observed for the LEC with the complex incorporating the sulfone substituent in the 4-position when operated under pulsed current driving conditions. PMID:27171612

  19. Active pixel sensor array with multiresolution readout

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Kemeny, Sabrina E. (Inventor); Pain, Bedabrata (Inventor)

    1999-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node. There is also a readout circuit, part of which can be disposed at the bottom of each column of cells and be common to all the cells in the column. The imaging device can also include an electronic shutter formed on the substrate adjacent the photogate, and/or a storage section to allow for simultaneous integration. In addition, the imaging device can include a multiresolution imaging circuit to provide images of varying resolution. The multiresolution circuit could also be employed in an array where the photosensitive portion of each pixel cell is a photodiode. This latter embodiment could further be modified to facilitate low light imaging.

  20. Further applications for mosaic pixel FPA technology

    NASA Astrophysics Data System (ADS)

    Liddiard, Kevin C.

    2011-06-01

    In previous papers to this SPIE forum the development of novel technology for next generation PIR security sensors has been described. This technology combines the mosaic pixel FPA concept with low cost optics and purpose-designed readout electronics to provide a higher performance and affordable alternative to current PIR sensor technology, including an imaging capability. Progressive development has resulted in increased performance and transition from conventional microbolometer fabrication to manufacture on 8 or 12 inch CMOS/MEMS fabrication lines. A number of spin-off applications have been identified. In this paper two specific applications are highlighted: high performance imaging IRFPA design and forest fire detection. The former involves optional design for small pixel high performance imaging. The latter involves cheap expendable sensors which can detect approaching fire fronts and send alarms with positional data via mobile phone or satellite link. We also introduce to this SPIE forum the application of microbolometer IR sensor technology to IoT, the Internet of Things.

  1. Efficient single pixel imaging in Fourier space

    NASA Astrophysics Data System (ADS)

    Bian, Liheng; Suo, Jinli; Hu, Xuemei; Chen, Feng; Dai, Qionghai

    2016-08-01

    Single pixel imaging (SPI) is a novel technique capturing 2D images using a bucket detector with a high signal-to-noise ratio, wide spectrum range and low cost. Conventional SPI projects random illumination patterns to randomly and uniformly sample the entire scene’s information. Determined by Nyquist sampling theory, SPI needs either numerous projections or high computation cost to reconstruct the target scene, especially for high-resolution cases. To address this issue, we propose an efficient single pixel imaging technique (eSPI), which instead projects sinusoidal patterns for importance sampling of the target scene’s spatial spectrum in Fourier space. Specifically, utilizing the centrosymmetric conjugation and sparsity priors of natural images’ spatial spectra, eSPI sequentially projects two \\tfrac{π }{2}-phase-shifted sinusoidal patterns to obtain each Fourier coefficient in the most informative spatial frequency bands. eSPI can reduce requisite patterns by two orders of magnitude compared to conventional SPI, which helps a lot for fast and high-resolution SPI.

  2. Multi-scale feature learning on pixels and super-pixels for seminal vesicles MRI segmentation

    NASA Astrophysics Data System (ADS)

    Gao, Qinquan; Asthana, Akshay; Tong, Tong; Rueckert, Daniel; Edwards, Philip "Eddie"

    2014-03-01

    We propose a learning-based approach to segment the seminal vesicles (SV) via random forest classifiers. The proposed discriminative approach relies on the decision forest using high-dimensional multi-scale context-aware spatial, textual and descriptor-based features at both pixel and super-pixel level. After affine transformation to a template space, the relevant high-dimensional multi-scale features are extracted and random forest classifiers are learned based on the masked region of the seminal vesicles from the most similar atlases. Using these classifiers, an intermediate probabilistic segmentation is obtained for the test images. Then, a graph-cut based refinement is applied to this intermediate probabilistic representation of each voxel to get the final segmentation. We apply this approach to segment the seminal vesicles from 30 MRI T2 training images of the prostate, which presents a particularly challenging segmentation task. The results show that the multi-scale approach and the augmentation of the pixel based features with the super-pixel based features enhances the discriminative power of the learnt classifier which leads to a better quality segmentation in some very difficult cases. The results are compared to the radiologist labeled ground truth using leave-one-out cross-validation. Overall, the Dice metric of 0:7249 and Hausdorff surface distance of 7:0803 mm are achieved for this difficult task.

  3. Geometrical modulation transfer function for different pixel active area shapes

    NASA Astrophysics Data System (ADS)

    Yadid-Pecht, Orly

    2000-04-01

    In this work we consider the effect of the pixel active area geometrical shape on the modulation transfer function (MTF) of an image sensor. When designing a CMOS Active Pixel Sensor, or a CCD or CID sensor for this matter, the active area of the pixel would have a certain geometrical shape which might not cover the whole pixel area. To improve the device performance, it is important to understand the effect this has on the pixel sensitivity and on the resulting MTF. We perform a theoretical analysis of the MTF for the active area shape and derive explicit formulas for the transfer function for pixel arrays with a square, a rectangular and an L shaped active area (most commonly used), and generalize for any connected active area shape. Preliminary experimental results of subpixel scanning sensitivity maps and the corresponding MTFs have also bee obtained, which confirm the theoretical derivations. Both the simulation results and the MTF calculated from the point spread function measurements of the actual pixel arrays show that the active area shape contributes significantly to the behavior of the overall MTF. The results also indicate that for any potential pixel active area shape, the effect of its diversion from the square pixel could be calculated, so that tradeoff between the conflicting requirements, such as SNR and MTF, could be compared per each pixel design for better overall sensor performance.

  4. Pixel response function experimental techniques and analysis of active pixel sensor star cameras

    NASA Astrophysics Data System (ADS)

    Fumo, Patrick; Waldron, Erik; Laine, Juha-Pekka; Evans, Gary

    2015-04-01

    The pixel response function (PRF) of a pixel within a focal plane is defined as the pixel intensity with respect to the position of a point source within the pixel. One of its main applications is in the field of astrometry, which is a branch of astronomy that deals with positioning data of a celestial body for tracking movement or adjusting the attitude of a spacecraft. Complementary metal oxide semiconductor (CMOS) image sensors generally offer better radiation tolerance to protons and heavy ions than CCDs making them ideal candidates for space applications aboard satellites, but like all image sensors they are limited by their spatial frequency response, better known as the modulation transfer function. Having a well-calibrated PRF allows us to eliminate some of the uncertainty in the spatial response of the system providing better resolution and a more accurate centroid estimation. This paper describes the experimental setup for determining the PRF of a CMOS image sensor and analyzes the effect on the oversampled point spread function (PSF) of an image intensifier, as well as the effects due to the wavelength of light used as a point source. It was found that using electron bombarded active pixel sensor (EBAPS) intensification technology had a significant impact on the PRF of the camera being tested as a result of an increase in the amount of carrier diffusion between collection sites generated by the intensification process. Taking the full width at half maximum (FWHM) of the resulting data, it was found that the intensified version of a CMOS camera exhibited a PSF roughly 16.42% larger than its nonintensified counterpart.

  5. Edge pixel response studies of edgeless silicon sensor technology for pixellated imaging detectors

    NASA Astrophysics Data System (ADS)

    Maneuski, D.; Bates, R.; Blue, A.; Buttar, C.; Doonan, K.; Eklund, L.; Gimenez, E. N.; Hynds, D.; Kachkanov, S.; Kalliopuska, J.; McMullen, T.; O'Shea, V.; Tartoni, N.; Plackett, R.; Vahanen, S.; Wraight, K.

    2015-03-01

    Silicon sensor technologies with reduced dead area at the sensor's perimeter are under development at a number of institutes. Several fabrication methods for sensors which are sensitive close to the physical edge of the device are under investigation utilising techniques such as active-edges, passivated edges and current-terminating rings. Such technologies offer the goal of a seamlessly tiled detection surface with minimum dead space between the individual modules. In order to quantify the performance of different geometries and different bulk and implant types, characterisation of several sensors fabricated using active-edge technology were performed at the B16 beam line of the Diamond Light Source. The sensors were fabricated by VTT and bump-bonded to Timepix ROICs. They were 100 and 200 μ m thick sensors, with the last pixel-to-edge distance of either 50 or 100 μ m. The sensors were fabricated as either n-on-n or n-on-p type devices. Using 15 keV monochromatic X-rays with a beam spot of 2.5 μ m, the performance at the outer edge and corners pixels of the sensors was evaluated at three bias voltages. The results indicate a significant change in the charge collection properties between the edge and 5th (up to 275 μ m) from edge pixel for the 200 μ m thick n-on-n sensor. The edge pixel performance of the 100 μ m thick n-on-p sensors is affected only for the last two pixels (up to 110 μ m) subject to biasing conditions. Imaging characteristics of all sensor types investigated are stable over time and the non-uniformities can be minimised by flat-field corrections. The results from the synchrotron tests combined with lab measurements are presented along with an explanation of the observed effects.

  6. How big is an OMI pixel?

    NASA Astrophysics Data System (ADS)

    de Graaf, Martin; Sihler, Holger; Tilstra, Lieuwe G.; Stammes, Piet

    2016-08-01

    The Ozone Monitoring Instrument (OMI) is a push-broom imaging spectrometer, observing solar radiation backscattered by the Earth's atmosphere and surface. The incoming radiation is detected using a static imaging CCD (charge-coupled device) detector array with no moving parts, as opposed to most of the previous satellite spectrometers, which used a moving mirror to scan the Earth in the across-track direction. The field of view (FoV) of detector pixels is the solid angle from which radiation is observed, averaged over the integration time of a measurement. The OMI FoV is not quadrangular, which is common for scanning instruments, but rather super-Gaussian shaped and overlapping with the FoV of neighbouring pixels. This has consequences for pixel-area-dependent applications, like cloud fraction products, and visualisation.The shapes and sizes of OMI FoVs were determined pre-flight by theoretical and experimental tests but never verified after launch. In this paper the OMI FoV is characterised using collocated MODerate resolution Imaging Spectroradiometer (MODIS) reflectance measurements. MODIS measurements have a much higher spatial resolution than OMI measurements and spectrally overlap at 469 nm. The OMI FoV was verified by finding the highest correlation between MODIS and OMI reflectances in cloud-free scenes, assuming a 2-D super-Gaussian function with varying size and shape to represent the OMI FoV. Our results show that the OMPIXCOR product 75FoV corner coordinates are accurate as the full width at half maximum (FWHM) of a super-Gaussian FoV model when this function is assumed. The softness of the function edges, modelled by the super-Gaussian exponents, is different in both directions and is view angle dependent.The optimal overlap function between OMI and MODIS reflectances is scene dependent and highly dependent on time differences between overpasses, especially with clouds in the scene. For partially clouded scenes, the optimal overlap function was

  7. Development of pixel detectors for SSC vertex tracking

    SciTech Connect

    Kramer, G. . Electro-Optical and Data Systems Group); Atlas, E.L.; Augustine, F.; Barken, O.; Collins, T.; Marking, W.L.; Worley, S.; Yacoub, G.Y. ) Shapiro, S.L. ); Arens, J.F.; Jernigan, J.G. . Space Sciences Lab.); Nygren,

    1991-04-01

    A description of hybrid PIN diode arrays and a readout architecture for their use as a vertex detector in the SSC environment is presented. Test results obtained with arrays having 256 {times} 256 pixels, each 30 {mu}m square, are also presented. The development of a custom readout for the SSC will be discussed, which supports a mechanism for time stamping hit pixels, storing their xy coordinates, and storing the analog information within the pixel. The peripheral logic located on the array, permits the selection of those pixels containing interesting data and their coordinates to be selectively read out. This same logic also resolves ambiguous pixel ghost locations and controls the pixel neighbor read out necessary to achieve high spatial resolution. The thermal design of the vertex tracker and the proposed signal processing architecture will also be discussed. 5 refs., 13 figs., 3 tabs.

  8. Pixel-level plasmonic microcavity infrared photodetector

    PubMed Central

    Jing, You Liang; Li, Zhi Feng; Li, Qian; Chen, Xiao Shuang; Chen, Ping Ping; Wang, Han; Li, Meng Yao; Li, Ning; Lu, Wei

    2016-01-01

    Recently, plasmonics has been central to the manipulation of photons on the subwavelength scale, and superior infrared imagers have opened novel applications in many fields. Here, we demonstrate the first pixel-level plasmonic microcavity infrared photodetector with a single quantum well integrated between metal patches and a reflection layer. Greater than one order of magnitude enhancement of the peak responsivity has been observed. The significant improvement originates from the highly confined optical mode in the cavity, leading to a strong coupling between photons and the quantum well, resulting in the enhanced photo-electric conversion process. Such strong coupling from the localized surface plasmon mode inside the cavity is independent of incident angles, offering a unique solution to high-performance focal plane array devices. This demonstration paves the way for important infrared optoelectronic devices for sensing and imaging. PMID:27181111

  9. Pixel-level plasmonic microcavity infrared photodetector

    NASA Astrophysics Data System (ADS)

    Jing, You Liang; Li, Zhi Feng; Li, Qian; Chen, Xiao Shuang; Chen, Ping Ping; Wang, Han; Li, Meng Yao; Li, Ning; Lu, Wei

    2016-05-01

    Recently, plasmonics has been central to the manipulation of photons on the subwavelength scale, and superior infrared imagers have opened novel applications in many fields. Here, we demonstrate the first pixel-level plasmonic microcavity infrared photodetector with a single quantum well integrated between metal patches and a reflection layer. Greater than one order of magnitude enhancement of the peak responsivity has been observed. The significant improvement originates from the highly confined optical mode in the cavity, leading to a strong coupling between photons and the quantum well, resulting in the enhanced photo-electric conversion process. Such strong coupling from the localized surface plasmon mode inside the cavity is independent of incident angles, offering a unique solution to high-performance focal plane array devices. This demonstration paves the way for important infrared optoelectronic devices for sensing and imaging.

  10. Distribution fitting-based pixel labeling for histology image segmentation

    NASA Astrophysics Data System (ADS)

    He, Lei; Long, L. Rodney; Antani, Sameer; Thoma, George

    2011-03-01

    This paper presents a new pixel labeling algorithm for complex histology image segmentation. For each image pixel, a Gaussian mixture model is applied to estimate its neighborhood intensity distributions. With this local distribution fitting, a set of pixels having a full set of source classes (e.g. nuclei, stroma, connective tissue, and background) in their neighborhoods are identified as the seeds for pixel labeling. A seed pixel is labeled by measuring its intensity distance to each of its neighborhood distributions, and the one with the shortest distance is selected to label the seed. For non-seed pixels, we propose two different labeling schemes: global voting and local clustering. In global voting each seed classifies a non-seed pixel into one of the seed's local distributions, i.e., it casts one vote; the final label for the non-seed pixel is the class which gets the most votes, across all the seeds. In local clustering, each non-seed pixel is labeled by one of its own neighborhood distributions. Because the local distributions in a non-seed pixel neighborhood do not necessarily correspond to distinct source classes (i.e., two or more local distributions may be produced by the same source class), we first identify the "true" source class of each local distribution by using the source classes of the seed pixels and a minimum distance criterion to determine the closest source class. The pixel can then be labeled as belonging to this class. With both labeling schemes, experiments on a set of uterine cervix histology images show encouraging performance of our algorithm when compared with traditional multithresholding and K-means clustering, as well as state-of-the-art mean shift clustering, multiphase active contours, and Markov random field-based algorithms.

  11. Steganography on quantum pixel images using Shannon entropy

    NASA Astrophysics Data System (ADS)

    Laurel, Carlos Ortega; Dong, Shi-Hai; Cruz-Irisson, M.

    2016-07-01

    This paper presents a steganographical algorithm based on least significant bit (LSB) from the most significant bit information (MSBI) and the equivalence of a bit pixel image to a quantum pixel image, which permits to make the information communicate secretly onto quantum pixel images for its secure transmission through insecure channels. This algorithm offers higher security since it exploits the Shannon entropy for an image.

  12. Data encoding efficiency in pixel detector readout with charge information

    NASA Astrophysics Data System (ADS)

    Garcia-Sciveres, Maurice; Wang, Xinkang

    2016-04-01

    The average minimum number of bits needed for lossless readout of a pixel detector is calculated, in the regime of interest for particle physics where only a small fraction of pixels have a non-zero value per frame. This permits a systematic comparison of the readout efficiency of different encoding implementations. The calculation is compared to the number of bits used by the FE-I4 pixel readout chip of the ATLAS experiment.

  13. Fast Pixel Buffer For Processing With Lookup Tables

    NASA Technical Reports Server (NTRS)

    Fisher, Timothy E.

    1992-01-01

    Proposed scheme for buffering data on intensities of picture elements (pixels) of image increases rate or processing beyond that attainable when data read, one pixel at time, from main image memory. Scheme applied in design of specialized image-processing circuitry. Intended to optimize performance of processor in which electronic equivalent of address-lookup table used to address those pixels in main image memory required for processing.

  14. Mapping Capacitive Coupling Among Pixels in a Sensor Array

    NASA Technical Reports Server (NTRS)

    Seshadri, Suresh; Cole, David M.; Smith, Roger M.

    2010-01-01

    An improved method of mapping the capacitive contribution to cross-talk among pixels in an imaging array of sensors (typically, an imaging photodetector array) has been devised for use in calibrating and/or characterizing such an array. The method involves a sequence of resets of subarrays of pixels to specified voltages and measurement of the voltage responses of neighboring non-reset pixels.

  15. Dead pixel correction techniques for dual-band infrared imagery

    NASA Astrophysics Data System (ADS)

    Nguyen, Chuong T.; Mould, Nick; Regens, James L.

    2015-07-01

    We present two new dead pixel correction algorithms for dual-band infrared imagery. Specifically, we address the problem of repairing unresponsive elements in the sensor array using signal processing techniques to overcome deficiencies in image quality that are present following the nonuniformity correction process. Traditionally, dead pixel correction has been performed almost exclusively using variations of the nearest neighbor technique, where the value of the dead pixel is estimated based on pixel values associated with the neighboring image structure. Our approach differs from existing techniques, for the first time we estimate the values of dead pixels using information from both thermal bands collaboratively. The proposed dual-band statistical lookup (DSL) and dual-band inpainting (DIP) algorithms use intensity and local gradient information to estimate the values of dead pixels based on the values of unaffected pixels in the supplementary infrared band. The DSL algorithm is a regression technique that uses the image intensities from the reference band to estimate the dead pixel values in the band undergoing correction. The DIP algorithm is an energy minimization technique that uses the local image gradient from the reference band and the boundary values from the affected band to estimate the dead pixel values. We evaluate the effectiveness of the proposed algorithms with 50 dual-band videos. Simulation results indicate that the proposed techniques achieve perceptually and quantitatively superior results compared to existing methods.

  16. Hit efficiency study of CMS prototype forward pixel detectors

    SciTech Connect

    Kim, Dongwook; /Johns Hopkins U.

    2006-01-01

    In this paper the author describes the measurement of the hit efficiency of a prototype pixel device for the CMS forward pixel detector. These pixel detectors were FM type sensors with PSI46V1 chip readout. The data were taken with the 120 GeV proton beam at Fermilab during the period of December 2004 to February 2005. The detectors proved to be highly efficient (99.27 {+-} 0.02%). The inefficiency was primarily located near the corners of the individual pixels.

  17. Evaluation of a single-pixel one-transistor active pixel sensor for fingerprint imaging

    NASA Astrophysics Data System (ADS)

    Xu, Man; Ou, Hai; Chen, Jun; Wang, Kai

    2015-08-01

    Since it first appeared in iPhone 5S in 2013, fingerprint identification (ID) has rapidly gained popularity among consumers. Current fingerprint-enabled smartphones unanimously consists of a discrete sensor to perform fingerprint ID. This architecture not only incurs higher material and manufacturing cost, but also provides only static identification and limited authentication. Hence as the demand for a thinner, lighter, and more secure handset grows, we propose a novel pixel architecture that is a photosensitive device embedded in a display pixel and detects the reflected light from the finger touch for high resolution, high fidelity and dynamic biometrics. To this purpose, an amorphous silicon (a-Si:H) dual-gate photo TFT working in both fingerprint-imaging mode and display-driving mode will be developed.

  18. Design and characterization of high precision in-pixel discriminators for rolling shutter CMOS pixel sensors with full CMOS capability

    NASA Astrophysics Data System (ADS)

    Fu, Y.; Hu-Guo, C.; Dorokhov, A.; Pham, H.; Hu, Y.

    2013-07-01

    In order to exploit the ability to integrate a charge collecting electrode with analog and digital processing circuitry down to the pixel level, a new type of CMOS pixel sensors with full CMOS capability is presented in this paper. The pixel array is read out based on a column-parallel read-out architecture, where each pixel incorporates a diode, a preamplifier with a double sampling circuitry and a discriminator to completely eliminate analog read-out bottlenecks. The sensor featuring a pixel array of 8 rows and 32 columns with a pixel pitch of 80 μm×16 μm was fabricated in a 0.18 μm CMOS process. The behavior of each pixel-level discriminator isolated from the diode and the preamplifier was studied. The experimental results indicate that all in-pixel discriminators which are fully operational can provide significant improvements in the read-out speed and the power consumption of CMOS pixel sensors.

  19. High-sensitivity (25-μm pitch) microbolometer FPAs and application development

    NASA Astrophysics Data System (ADS)

    Murphy, Daniel F.; Ray, Michael; Wyles, Richard; Asbrock, James F.; Lum, Nancy A.; Kennedy, Adam; Wyles, Jessica; Hewitt, C.; Graham, Glen E.; Radford, William A.; Anderson, John S.; Bradley, Daryl; Chin, Richard; Kostrzewa, Thomas

    2001-10-01

    Raytheon Infrared Operations (RIO) has achieved a significant technical breakthrough in uncooled FPAs by reducing the pixel size by a factor of two while maintaining state-of-the-art sensitivity. Raytheon has produced high-quality 320 X 240 microbolometer FPAs with 25 μm pitch pixels. The 320 X 240 FPAs have a sensitivity that is comparable to microbolometer FPAs with 50 micrometers pixels. The average NETD value for these FPAs is about 35 mK with an f/1 aperture and operating at 30 Hz frame rates. Good pixel operability and excellent image quality have been demonstrated. Pixel operability is greater than 99% on some FPAs, and uncorrected responsivity nonuniformity is less than 4% (sigma/mean). The microbolometer detectors also have a relatively fast thermal time constant of approximately 10 msec. This state-of-the-art performance has been achieved as a result of an advanced micromachining fabrication process. The process allows maximization of both the thermal isolation and the optical fill-factor. The reduction in pixel size offers several potential benefits for IR systems. For a given system resolution (IFOV) requirement, the 25 μm pixels allow a factor of two reduction in both the focal length and aperture size of the sensor optics. The pixel size reduction facilitates a significant FPA cost reduction since the number of die printed on a wafer can be increased. The pixel size reduction has enabled the development of a large-format 640 X 512 FPA array applicable to wide-field-of-view, long range surveillance and targeting missions, and a 160 X 128 array where applications for miniaturization and temperature invariance are required as well as low cost and low power.

  20. Hybrid Pixel Detectors for gamma/X-ray imaging

    NASA Astrophysics Data System (ADS)

    Hatzistratis, D.; Theodoratos, G.; Zografos, V.; Kazas, I.; Loukas, D.; Lambropoulos, C. P.

    2015-09-01

    Hybrid pixel detectors are made by direct converting high-Z semi-insulating single crystalline material coupled to complementary-metal-oxide semiconductor (CMOS) readout electronics. They are attractive because direct conversion exterminates all the problems of spatial localization related to light diffusion, energy resolution, is far superior from the combination of scintillation crystals and photomultipliers and lithography can be used to pattern electrodes with very fine pitch. We are developing 2-D pixel CMOS ASICs, connect them to pixilated CdTe crystals with the flip chip and bump bonding method and characterize the hybrids. We have designed a series of circuits, whose latest member consists of a 50×25 pixel array with 400um pitch and an embedded controller. In every pixel a full spectroscopic channel with time tagging information has been implemented. The detectors are targeting Compton scatter imaging and they can be used for coded aperture imaging too. Hybridization using CMOS can overcome the limit put on pixel circuit complexity by the use of thin film transistors (TFT) in large flat panels. Hybrid active pixel sensors are used in dental imaging and other applications (e.g. industrial CT etc.). Thus X-ray imaging can benefit from the work done on dynamic range enhancement methods developed initially for visible and infrared CMOS pixel sensors. A 2-D CMOS ASIC with 100um pixel pitch to demonstrate the feasibility of such methods in the context of X-ray imaging has been designed.

  1. Novel integrated CMOS pixel structures for vertex detectors

    SciTech Connect

    Kleinfelder, Stuart; Bieser, Fred; Chen, Yandong; Gareus, Robin; Matis, Howard S.; Oldenburg, Markus; Retiere, Fabrice; Ritter, Hans Georg; Wieman, Howard H.; Yamamoto, Eugene

    2003-10-29

    Novel CMOS active pixel structures for vertex detector applications have been designed and tested. The overriding goal of this work is to increase the signal to noise ratio of the sensors and readout circuits. A large-area native epitaxial silicon photogate was designed with the aim of increasing the charge collected per struck pixel and to reduce charge diffusion to neighboring pixels. The photogate then transfers the charge to a low capacitance readout node to maintain a high charge to voltage conversion gain. Two techniques for noise reduction are also presented. The first is a per-pixel kT/C noise reduction circuit that produces results similar to traditional correlated double sampling (CDS). It has the advantage of requiring only one read, as compared to two for CDS, and no external storage or subtraction is needed. The technique reduced input-referred temporal noise by a factor of 2.5, to 12.8 e{sup -}. Finally, a column-level active reset technique is explored that suppresses kT/C noise during pixel reset. In tests, noise was reduced by a factor of 7.6 times, to an estimated 5.1 e{sup -} input-referred noise. The technique also dramatically reduces fixed pattern (pedestal) noise, by up to a factor of 21 in our tests. The latter feature may possibly reduce pixel-by-pixel pedestal differences to levels low enough to permit sparse data scan without per-pixel offset corrections.

  2. Development of a pixel readout chip for BTeV

    SciTech Connect

    D.C. Christian et al.

    1998-11-01

    A description is given of the R&D program underway at Fermilab to develop a pixel readout ASIC appropriate for use at the Tevatron collider. Results are presentetd frOm tests performed on the first prototype pixel readout chip deigned at Fermilab, and a new readout architecture is described.

  3. Method for hyperspectral imagery exploitation and pixel spectral unmixing

    NASA Technical Reports Server (NTRS)

    Lin, Ching-Fang (Inventor)

    2003-01-01

    An efficiently hybrid approach to exploit hyperspectral imagery and unmix spectral pixels. This hybrid approach uses a genetic algorithm to solve the abundance vector for the first pixel of a hyperspectral image cube. This abundance vector is used as initial state in a robust filter to derive the abundance estimate for the next pixel. By using Kalman filter, the abundance estimate for a pixel can be obtained in one iteration procedure which is much fast than genetic algorithm. The output of the robust filter is fed to genetic algorithm again to derive accurate abundance estimate for the current pixel. The using of robust filter solution as starting point of the genetic algorithm speeds up the evolution of the genetic algorithm. After obtaining the accurate abundance estimate, the procedure goes to next pixel, and uses the output of genetic algorithm as the previous state estimate to derive abundance estimate for this pixel using robust filter. And again use the genetic algorithm to derive accurate abundance estimate efficiently based on the robust filter solution. This iteration continues until pixels in a hyperspectral image cube end.

  4. Singlet mega-pixel resolution lens

    NASA Astrophysics Data System (ADS)

    Lin, Chen-Hung; Lin, Hoang Yan; Chang, Horng

    2008-03-01

    There always exist some new challenges for lens designers to keep their old-line technology update. To minimize lens volume is one of the most notified examples. In this paper we designed a single thick lens, constructed by using one oblique (reflective) surface, apart from two conventional refractive surfaces, to bend the optical path of the optical system to achieve this goal. Detail design procedure, including system layout and lens performance diagrams, will be presented. Following the first order layout, we applied aspherical form to the two refractive surfaces in order to correct the spherical aberration up to an acceptable condition. Then, the reduced aberrations such as coma, astigmatism, field curvature and distortion can easily be corrected with some calculations related to spherical aberration as shown in the publication of H. H. Hopkins (1950). Plastic material is used in the design, because the aspherical surfaces can then be manufactured in a more cost effective way. The final specification of the design is: EFL is 4.6 mm, the F number is 2.8, the over all thickness of lens is 3.6 mm, its MTF is 0.3 at 227 lp/mm in center field and chief ray angle is less than 15 degrees. Lens data as well as optical performance curves are also presented in the paper. In conclusion we have successfully finished a mega-pixel resolution lens design and its overall thickness is compatible with the state of the art.

  5. Status of the CMS Phase I pixel detector upgrade

    NASA Astrophysics Data System (ADS)

    Spannagel, S.

    2016-09-01

    A new pixel detector for the CMS experiment is being built, owing to the instantaneous luminosities anticipated for the Phase I Upgrade of the LHC. The new CMS pixel detector provides four-hit tracking while featuring a significantly reduced material budget as well as new cooling and powering schemes. A new front-end readout chip mitigates buffering and bandwidth limitations, and comprises a low-threshold comparator. These improvements allow the new pixel detector to sustain and improve the efficiency of the current pixel tracker at the increased requirements imposed by high luminosities and pile-up. This contribution gives an overview of the design of the upgraded pixel detector and the status of the upgrade project, and presents test beam performance measurements of the production read-out chip.

  6. DC-DC powering for the CMS pixel upgrade

    NASA Astrophysics Data System (ADS)

    Feld, Lutz; Fleck, Martin; Friedrichs, Marcel; Hensch, Richard; Karpinski, Waclaw; Klein, Katja; Rittich, David; Sammet, Jan; Wlochal, Michael

    2013-12-01

    The CMS experiment plans to replace its silicon pixel detector with a new one with improved rate capability and an additional detection layer at the end of 2016. In order to cope with the increased number of detector modules the new pixel detector will be powered via DC-DC converters close to the sensitive detector volume. This paper reviews the DC-DC powering scheme and reports on the ongoing R&D program to develop converters for the pixel upgrade. Design choices are discussed and results from the electrical and thermal characterisation of converter prototypes are shown. An emphasis is put on system tests with up to 24 converters. The performance of pixel modules powered by DC-DC converters is compared to conventional powering. The integration of the DC-DC powering scheme into the pixel detector is described and system design issues are reviewed.

  7. Attenuating Stereo Pixel-Locking via Affine Window Adaptation

    NASA Technical Reports Server (NTRS)

    Stein, Andrew N.; Huertas, Andres; Matthies, Larry H.

    2006-01-01

    For real-time stereo vision systems, the standard method for estimating sub-pixel stereo disparity given an initial integer disparity map involves fitting parabolas to a matching cost function aggregated over rectangular windows. This results in a phenomenon known as 'pixel-locking,' which produces artificially-peaked histograms of sub-pixel disparity. These peaks correspond to the introduction of erroneous ripples or waves in the 3D reconstruction of truly Rat surfaces. Since stereo vision is a common input modality for autonomous vehicles, these inaccuracies can pose a problem for safe, reliable navigation. This paper proposes a new method for sub-pixel stereo disparity estimation, based on ideas from Lucas-Kanade tracking and optical flow, which substantially reduces the pixel-locking effect. In addition, it has the ability to correct much larger initial disparity errors than previous approaches and is more general as it applies not only to the ground plane.

  8. Readout of TPC Tracking Chambers with GEMs and Pixel Chip

    SciTech Connect

    Kadyk, John; Kim, T.; Freytsis, M.; Button-Shafer, J.; Kadyk, J.; Vahsen, S.E.; Wenzel, W.A.

    2007-12-21

    Two layers of GEMs and the ATLAS Pixel Chip, FEI3, have been combined and tested as a prototype for Time Projection Chamber (TPC) readout at the International Linear Collider (ILC). The double-layer GEM system amplifies charge with gain sufficient to detect all track ionization. The suitability of three gas mixtures for this application was investigated, and gain measurements are presented. A large sample of cosmic ray tracks was reconstructed in 3D by using the simultaneous timing and 2D spatial information from the pixel chip. The chip provides pixel charge measurement as well as timing. These results demonstrate that a double GEM and pixel combination, with a suitably modified pixel ASIC, could meet the stringent readout requirements of the ILC.

  9. Using an Active Pixel Sensor In A Vertex Detector

    SciTech Connect

    Matis, Howard S.; Bieser, Fred; Chen, Yandong; Gareus, Robin; Kleinfelder, Stuart; Oldenburg, Markus; Retiere, Fabrice; Ritter, HansGeorg; Wieman, Howard H.; Wurzel, Samuel E.; Yamamoto, Eugene

    2004-04-22

    Research has shown that Active Pixel CMOS sensors can detect charged particles. We have been studying whether this process can be used in a collider environment. In particular, we studied the effect of radiation with 55 MeV protons. These results show that a fluence of about 2 x 10{sup 12} protons/cm{sup 2} reduces the signal by a factor of two while the noise increases by 25%. A measurement 6 months after exposure shows that the silicon lattice naturally repairs itself. Heating the silicon to 100 C reduced the shot noise and increased the collected charge. CMOS sensors have a reduced signal to noise ratio per pixel because charge diffuses to neighboring pixels. We have constructed a photogate to see if this structure can collect more charge per pixel. Results show that a photogate does collect charge in fewer pixels, but it takes about 15 ms to collect all of the electrons produced by a pulse of light.

  10. Detector apparatus having a hybrid pixel-waveform readout system

    DOEpatents

    Meng, Ling-Jian

    2014-10-21

    A gamma ray detector apparatus comprises a solid state detector that includes a plurality of anode pixels and at least one cathode. The solid state detector is configured for receiving gamma rays during an interaction and inducing a signal in an anode pixel and in a cathode. An anode pixel readout circuit is coupled to the plurality of anode pixels and is configured to read out and process the induced signal in the anode pixel and provide triggering and addressing information. A waveform sampling circuit is coupled to the at least one cathode and configured to read out and process the induced signal in the cathode and determine energy of the interaction, timing of the interaction, and depth of interaction.

  11. Single photon counting pixel detectors for synchrotron radiation experiments

    NASA Astrophysics Data System (ADS)

    Toyokawa, H.; Broennimann, Ch.; Eikenberry, E. F.; Henrich, B.; Kawase, M.; Kobas, M.; Kraft, P.; Sato, M.; Schmitt, B.; Suzuki, M.; Tanida, H.; Uruga, T.

    2010-11-01

    At the Paul Scherrer Institute PSI an X-ray single photon counting pixel detector (PILATUS) based on the hybrid-pixel detector technology was developed in collaboration with SPring-8. The detection element is a 320 or 450 μm thick silicon sensor forming pixelated pn-diodes with a pitch of 172 μm×172 μm. An array of 2×8 custom CMOS readout chips are indium bump-bonded to the sensor, which leads to 33.5 mm×83.8 mm detective area. Each pixel contains a charge-sensitive amplifier, a single level discriminator and a 20 bit counter. This design realizes a high dynamic range, short readout time of less than 3 ms, a high framing rate of over 200 images per second and an excellent point-spread function. The maximum counting rate achieves more than 2×10 6 X-rays/s/pixel.

  12. Development of a novel pixel-level signal processing chain for fast readout 3D integrated CMOS pixel sensors

    NASA Astrophysics Data System (ADS)

    Fu, Y.; Torheim, O.; Hu-Guo, C.; Degerli, Y.; Hu, Y.

    2013-03-01

    In order to resolve the inherent readout speed limitation of traditional 2D CMOS pixel sensors, operated in rolling shutter readout, a parallel readout architecture has been developed by taking advantage of 3D integration technologies. Since the rows of the pixel array are zero-suppressed simultaneously instead of sequentially, a frame readout time of a few microseconds is expected for coping with high hit rates foreseen in future collider experiments. In order to demonstrate the pixel readout functionality of such a pixel sensor, a 2D proof-of-concept chip including a novel pixel-level signal processing chain was designed and fabricated in a 0.13 μm CMOS technology. The functionalities of this chip have been verified through experimental characterization.

  13. Analysis of Multipath Pixels in SAR Images

    NASA Astrophysics Data System (ADS)

    Zhao, J. W.; Wu, J. C.; Ding, X. L.; Zhang, L.; Hu, F. M.

    2016-06-01

    As the received radar signal is the sum of signal contributions overlaid in one single pixel regardless of the travel path, the multipath effect should be seriously tackled as the multiple bounce returns are added to direct scatter echoes which leads to ghost scatters. Most of the existing solution towards the multipath is to recover the signal propagation path. To facilitate the signal propagation simulation process, plenty of aspects such as sensor parameters, the geometry of the objects (shape, location, orientation, mutual position between adjacent buildings) and the physical parameters of the surface (roughness, correlation length, permittivity)which determine the strength of radar signal backscattered to the SAR sensor should be given in previous. However, it's not practical to obtain the highly detailed object model in unfamiliar area by field survey as it's a laborious work and time-consuming. In this paper, SAR imaging simulation based on RaySAR is conducted at first aiming at basic understanding of multipath effects and for further comparison. Besides of the pre-imaging simulation, the product of the after-imaging, which refers to radar images is also taken into consideration. Both Cosmo-SkyMed ascending and descending SAR images of Lupu Bridge in Shanghai are used for the experiment. As a result, the reflectivity map and signal distribution map of different bounce level are simulated and validated by 3D real model. The statistic indexes such as the phase stability, mean amplitude, amplitude dispersion, coherence and mean-sigma ratio in case of layover are analyzed with combination of the RaySAR output.

  14. Pixel Analysis and Plasma Dynamics Characterized by Photospheric Spectral Data

    NASA Astrophysics Data System (ADS)

    Rasca, A.; Chen, J.; Pevtsov, A. A.

    2015-12-01

    Continued advances in solar observations have led to higher-resolution magnetograms and surface (photospheric) images, revealing bipolar magnetic features operating near the resolution limit during emerging flux events and other phenomena used to predict solar eruptions responsible for geomagnetic plasma disturbances. However, line of sight (LOS) magnetogram pixels only contain the net uncanceled magnetic flux, which is expected to increase for fixed regions as resolution limits improve. A pixel dynamics model utilizing Stokes I spectral profiles was previously-used to quantify changes in the Doppler shift, width, asymmetry, and tail flatness of Fe I lines at 6301.5 and 6302.5 Å and used pixel-by-pixel line profile fluctuations to characterize quiet and active regions on the Sun. We use this pixel dynamics model with circularly polarized photospheric data (e.g., SOLIS data) to estimate plasma dynamic properties at a sub-pixel level. The analysis can be extended to include the full Stokes parameters and study signatures of magnetic fields and coupled plasma properties on sub-pixel scales.

  15. Monolithic pixels on moderate resistivity substrate and sparsifying readout architecture

    NASA Astrophysics Data System (ADS)

    Giubilato, P.; Battaglia, M.; Bisello, D.; Caselle, M.; Chalmet, P.; Demaria, L.; Ikemoto, Y.; Kloukinas, K.; Mansuy, S. C.; Mattiazzo, S.; Marchioro, A.; Mugnier, H.; Pantano, D.; Potenza, A.; Rivetti, A.; Rousset, J.; Silvestrin, L.; Snoeys, W.

    2013-12-01

    The LePix projects aim realizing a new generation monolithic pixel detectors with improved performances at lesser cost with respect to both current state of the art monolithic and hybrid pixel sensors. The detector is built in a 90 nm CMOS process on a substrate of moderate resistivity. This allows charge collection by drift while maintaining the other advantages usually offered by MAPS, like having a single piece detector and using a standard CMOS production line. The collection by drift mechanism, coupled to the low capacitance design of the collecting node made possible by the monolithic approach, provides an excellent signal to noise ratio straight at the pixel cell together with a radiation tolerance far superior to conventional un-depleted MAPS. The excellent signal-to-noise performance is demonstrated by the device ability to separate the 6 keV 55Fe double peak at room temperature. To achieve high granularity (10-20 μm pitch pixels) over large detector areas maintaining high readout speed, a completely new compressing architecture has been devised. This architecture departs from the mainstream hybrid pixel sparsification approach, which uses in-pixel logic to reduce data, by using topological compression to minimize pixel area and power consumption.

  16. Monolithic pixel detectors with 0.2 μm FD-SOI pixel process technology

    NASA Astrophysics Data System (ADS)

    Miyoshi, Toshinobu; Arai, Yasuo; Chiba, Tadashi; Fujita, Yowichi; Hara, Kazuhiko; Honda, Shunsuke; Igarashi, Yasushi; Ikegami, Yoichi; Ikemoto, Yukiko; Kohriki, Takashi; Ohno, Morifumi; Ono, Yoshimasa; Shinoda, Naoyuki; Takeda, Ayaki; Tauchi, Kazuya; Tsuboyama, Toru; Tadokoro, Hirofumi; Unno, Yoshinobu; Yanagihara, Masashi

    2013-12-01

    Truly monolithic pixel detectors were fabricated with 0.2 μm SOI pixel process technology by collaborating with LAPIS Semiconductor Co., Ltd. for particle tracking experiment, X-ray imaging and medical applications. CMOS circuits were fabricated on a thin SOI layer and connected to diodes formed in the silicon handle wafer through the buried oxide layer. We can choose the handle wafer and therefore high-resistivity silicon is also available. Double SOI (D-SOI) wafers fabricated from Czochralski (CZ)-SOI wafers were newly obtained and successfully processed in 2012. The top SOI layers are used as electric circuits and the middle SOI layers used as a shield layer against the back-gate effect and cross-talk between sensors and CMOS circuits, and as an electrode to compensate for the total ionizing dose (TID) effect. In 2012, we developed two SOI detectors, INTPIX5 and INTPIX3g. A spatial resolution study was done with INTPIX5 and it showed excellent performance. The TID effect study with D-SOI INTPIX3g detectors was done and we confirmed improvement of TID tolerance in D-SOI sensors.

  17. Vertically integrated pixel readout chip for high energy physics

    SciTech Connect

    Deptuch, Grzegorz; Demarteau, Marcel; Hoff, James; Khalid, Farah; Lipton, Ronald; Shenai, Alpana; Trimpl, Marcel; Yarema, Raymond; Zimmerman, Tom; /Fermilab

    2011-01-01

    We report on the development of the vertex detector pixel readout chips based on multi-tier vertically integrated electronics for the International Linear Collider. Some testing results of the VIP2a prototype are presented. The chip is the second iteration of the silicon implementation of the prototype, data-pushed concept of the readout developed at Fermilab. The device was fabricated in the 3D MIT-LL 0.15 {micro}m fully depleted SOI process. The prototype is a three-tier design, featuring 30 x 30 {micro}m{sup 2} pixels, laid out in an array of 48 x 48 pixels.

  18. Pixel detectors in 3D technologies for high energy physics

    SciTech Connect

    Deptuch, G.; Demarteau, M.; Hoff, J.; Lipton, R.; Shenai, A.; Yarema, R.; Zimmerman, T.; /Fermilab

    2010-10-01

    This paper reports on the current status of the development of International Linear Collider vertex detector pixel readout chips based on multi-tier vertically integrated electronics. Initial testing results of the VIP2a prototype are presented. The chip is the second embodiment of the prototype data-pushed readout concept developed at Fermilab. The device was fabricated in the MIT-LL 0.15 {micro}m fully depleted SOI process. The prototype is a three-tier design, featuring 30 x 30 {micro}m{sup 2} pixels, laid out in an array of 48 x 48 pixels.

  19. Dual collection mode optical microscope with single-pixel detection

    NASA Astrophysics Data System (ADS)

    Rodríguez, A. D.; Clemente, P.; Fernández-Alonso, Mercedes; Tajahuerce, E.; Lancis, J.

    2015-07-01

    In this work we have developed a single-pixel optical microscope that provides both re ection and transmission images of the sample under test by attaching a diamond pixel layout DMD to a commercial inverted microscope. Our system performs simultaneous measurements of re ection and transmission modes. Besides, in contrast with a conventional system, in our single-element detection system both images belong, unequivocally, to the same plane of the sample. Furthermore, we have designed an algorithm to modify the shape of the projected patterns that improves the resolution and prevents the artifacts produced by the diamond pixel architecture.

  20. Consequences of Mixed Pixels on Temperature Emissivity Separation

    SciTech Connect

    Heasler, Patrick G.; Foley, Michael G.; Thompson, Sandra E.

    2007-02-01

    This report investigates the effect that a mixed pixel can have on temperature/emissivity seperation (i.e. temperature/emissivity estimation using long-wave infra-red data). Almost all temperature/emissivity estimation methods are based on a model that assumes both temperature and emissivity within the imaged pixel is homogeneous. A mixed pixel has heterogeneous temperature/emissivity and therefore does not satisfy the assumption. Needless to say, this heterogeneity causes biases in the estimates and this report quantifies the magnitude of the biases.

  1. Resolution and sensitivity improvements for VOx microbolometer FPAs

    NASA Astrophysics Data System (ADS)

    Murphy, Daniel F.; Kennedy, Adam; Ray, Michael; Wyles, Richard; Wyles, Jessica; Asbrock, James F.; Hewitt, C.; Van Lue, David; Sessler, T.; Anderson, John S.; Bradley, Daryl; Chin, Richard; Gonzales, H.; Le Pere, C.; Kostrzewa, Thomas

    2003-09-01

    Raytheon Vision Systems (RVS) has achieved a significant technical breakthrough in uncooled FPAs by reducing the pixel size by a factor of two while maintaining state-of-the-art sensitivity. Raytheon is producing high-quality 320 x 240 microbolometer FPAs with 25 μm pitch pixels. The 320 x 240 FPAs have a sensitivity that is comparable to microbolometer FPAs with 50 μm pixels. The array average NETD value for these FPAs is about 30 mK with an f/1 aperture and operating at 30 Hz frame rates. Pixel operability is greater than 99% on most FPAs, and uncorrected responsivity nonuniformity is less than 4% (sigma/mean). These 25 μm microbolometer detectors also have a relatively fast thermal time constant of approximately 10 msec. This state-of-the-art performance has been achieved as a result of an advanced micro machining fabrication process, which allows maximization of both the thermal isolation and the optical fill-factor. These arrays have produced excellent image quality, and are currently fielded in demonstration systems. The reduction in pixel size offers several potential benefits for IR systems. For a given system resolution (IFOV) requirement, the 25 μm pxiels allow a factor of two reduction in both the focal length and aperture size of the sensor optics. These FPAs are applicable to wide-field-of-view, long-range surveillance and targeting missions. The pixel size reduction facilitates a significant FPA cost reduction since the number of die printed on a wafer can be increased, and also has enabled the development of a large-format 640 x 480 FPA array. Raytheon is producing these arrays with very good sensitivity. These arrays have excellent operability and image quality. Several dual FOV prototype systems have been delivered under the LCMS and UAV programs, and are under evaluation at NVESD. Raytheon Vision Systems (RVS) has developed a flexible uncooled front end (UFE) electronics that will serve as the basis for camera engine systems using 320 x 240

  2. A germanium hybrid pixel detector with 55μm pixel size and 65,000 channels

    NASA Astrophysics Data System (ADS)

    Pennicard, D.; Struth, B.; Hirsemann, H.; Sarajlic, M.; Smoljanin, S.; Zuvic, M.; Lampert, M. O.; Fritzsch, T.; Rothermund, M.; Graafsma, H.

    2014-12-01

    Hybrid pixel semiconductor detectors provide high performance through a combination of direct detection, a relatively small pixel size, fast readout and sophisticated signal processing circuitry in each pixel. For X-ray detection above 20 keV, high-Z sensor layers rather than silicon are needed to achieve high quantum efficiency, but many high-Z materials such as GaAs and CdTe often suffer from poor material properties or nonuniformities. Germanium is available in large wafers of extremely high quality, making it an appealing option for high-performance hybrid pixel X-ray detectors, but suitable technologies for finely pixelating and bump-bonding germanium have not previously been available. A finely-pixelated germanium photodiode sensor with a 256 by 256 array of 55μm pixels has been produced. The sensor has an n-on-p structure, with 700μm thickness. Using a low-temperature indium bump process, this sensor has been bonded to the Medipix3RX photoncounting readout chip. Tests with the LAMBDA readout system have shown that the detector works successfully, with a high bond yield and higher image uniformity than comparable high-Z systems. During cooling, the system is functional around -80°C (with warmer temperatures resulting in excessive leakage current), with -100°C sufficient for good performance.

  3. Characterization of a three side abuttable CMOS pixel sensor with digital pixel and data compression for charged particle tracking

    NASA Astrophysics Data System (ADS)

    Guilloux, F.; Değerli, Y.; Flouzat, C.; Lachkar, M.; Monmarthe, E.; Orsini, F.; Venault, P.

    2016-02-01

    CMOS monolithic pixel sensor technology has been chosen to equip the new ALICE trackers for HL-LHC . PIXAM is the final prototype from an R&D program specific to the Muon Forward Tracker which intends to push significantly forward the performances of the mature rolling shutter architecture. By implementing a digital pixel allowing to readout of a group of rows in parallel, the PIXAM sensor increases the rolling shutter readout speed while keeping the same power consumption as that of analogue pixel sensors. This paper will describe shortly the ASIC architecture and will focus on the analogue and digital performances of the sensor, obtained from laboratory measurements.

  4. Coherence experiments in single-pixel digital holography.

    PubMed

    Liu, Jung-Ping; Guo, Chia-Hao; Hsiao, Wei-Jen; Poon, Ting-Chung; Tsang, Peter

    2015-05-15

    In optical scanning holography (OSH), the coherence properties of the acquired holograms depend on the single-pixel size, i.e., the active area of the photodetector. For the first time, to the best of our knowledge, we have demonstrated coherent, partial coherent, and incoherent three-dimensional (3D) imaging by experiment in such a single-pixel digital holographic recording system. We have found, for the incoherent mode of OSH, in which the detector of the largest active area is applied, the 3D location of a diffusely reflecting object can be successfully retrieved without speckle noise. For the partial coherent mode employing a smaller pixel size of the detector, significant speckles and randomly distributed bright spots appear among the reconstructed images. For the coherent mode of OSH when the size of the pixel is vanishingly small, the bright spots disappear. However, the speckle remains and the signal-to-noise ratio is low. PMID:26393741

  5. Active pixel sensors with substantially planarized color filtering elements

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Kemeny, Sabrina E. (Inventor)

    1999-01-01

    A semiconductor imaging system preferably having an active pixel sensor array compatible with a CMOS fabrication process. Color-filtering elements such as polymer filters and wavelength-converting phosphors can be integrated with the image sensor.

  6. DAQ hardware and software development for the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Stramaglia, Maria Elena

    2016-07-01

    In 2014, the Pixel Detector of the ATLAS experiment has been extended by about 12 million pixels thanks to the installation of the Insertable B-Layer (IBL). Data-taking and tuning procedures have been implemented along with newly designed readout hardware to support high bandwidth for data readout and calibration. The hardware is supported by an embedded software stack running on the readout boards. The same boards will be used to upgrade the readout bandwidth for the two outermost barrel layers of the ATLAS Pixel Detector. We present the IBL readout hardware and the supporting software architecture used to calibrate and operate the 4-layer ATLAS Pixel Detector. We discuss the technical implementations and status for data taking, validation of the DAQ system in recent cosmic ray data taking, in-situ calibrations, and results from additional tests in preparation for Run 2 at the LHC.

  7. Two-dimensional pixel array image sensor for protein crystallography

    SciTech Connect

    Beuville, E.; Beche, J.-F.; Cork, C.

    1996-07-01

    A 2D pixel array image sensor module has been designed for time resolved Protein Crystallography. This smart pixels detector significantly enhances time resolved Laue Protein crystallography by two to three orders of magnitude compared to existing sensors like films or phosphor screens coupled to CCDs. The resolution in time and dynamic range of this type of detector will allow one to study the evolution of structural changes that occur within the protein as a function of time. This detector will also considerably accelerate data collection in static Laue or monochromatic crystallography and make better use of the intense beam delivered by synchrotron light sources. The event driven pixel array detectors, based on the column Architecture, can provide multiparameter information (energy discrimination, time), with sparse and frameless readout without significant dead time. The prototype module consists of a 16x16 pixel diode array bump-bonded to the integrated circuit. The detection area is 150x150 square microns.

  8. Small pixel CZT detector for hard X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Wilson, Matthew David; Cernik, Robert; Chen, Henry; Hansson, Conny; Iniewski, Kris; Jones, Lawrence L.; Seller, Paul; Veale, Matthew C.

    2011-10-01

    A new small pixel cadmium zinc telluride (CZT) detector has been developed for hard X-ray spectroscopy. The X-ray performance of four detectors is presented and the detectors are analysed in terms of the energy resolution of each pixel. The detectors were made from CZT crystals grown by the travelling heater method (THM) bonded to a 20×20 application specific integrated circuit (ASIC) and data acquisition (DAQ) system. The detectors had an array of 20×20 pixels on a 250 μm pitch, with each pixel gold-stud bonded to an energy resolving circuit in the ASIC. The DAQ system digitised the ASIC output with 14 bit resolution, performing offset corrections and data storage to disc in real time at up to 40,000 frames per second. The detector geometry and ASIC design was optimised for X-ray spectroscopy up to 150 keV and made use of the small pixel effect to preferentially measure the electron signal. A 241Am source was used to measure the spectroscopic performance and uniformity of the detectors. The average energy resolution (FWHM at 59.54 keV) of each pixel ranged from 1.09±0.46 to 1.50±0.57 keV across the four detectors. The detectors showed good spectral performance and uniform response over almost all pixels in the 20×20 array. A large area 80×80 pixel detector will be built that will utilise the scalable design of the ASIC and the large areas of monolithic spectroscopic grade THM grown CZT that are now available. The large area detector will have the same performance as that demonstrated here.

  9. A Chip and Pixel Qualification Methodology on Imaging Sensors

    NASA Technical Reports Server (NTRS)

    Chen, Yuan; Guertin, Steven M.; Petkov, Mihail; Nguyen, Duc N.; Novak, Frank

    2004-01-01

    This paper presents a qualification methodology on imaging sensors. In addition to overall chip reliability characterization based on sensor s overall figure of merit, such as Dark Rate, Linearity, Dark Current Non-Uniformity, Fixed Pattern Noise and Photon Response Non-Uniformity, a simulation technique is proposed and used to project pixel reliability. The projected pixel reliability is directly related to imaging quality and provides additional sensor reliability information and performance control.

  10. Pixel readout electronics for LHC and biomedical applications

    NASA Astrophysics Data System (ADS)

    Blanquart, L.; Bonzom, V.; Comes, G.; Delpierre, P.; Fischer, P.; Hausmann, J.; Keil, M.; Lindner, M.; Meuser, S.; Wermes, N.

    2000-01-01

    The demanding requirements for pixel readout electronics for high-energy physics experiments and biomedical applications are reviewed. Some examples of the measured analog performance of prototype chips are given. The readout architectures of the PIxel Readout for the ATlas Experiment (PIRATE) chip suited for LHC experiments and of the Multi Picture Element Counter (MPEC) counting chip targeted for biomedical applications are presented. First results with complete chip-sensor assemblies are also shown.

  11. FPIX2, the BTeV pixel readout chip

    SciTech Connect

    David C. Christian et al.

    2003-12-10

    A radiation tolerant pixel readout chip, FPIX2, has been developed at Fermilab for use by BTeV. Some of the requirements of the BTeV pixel readout chip are reviewed and contrasted with requirements for similar devices in LHC experiments. A description of the FPIX2 is given, and results of initial tests of its performance are presented, as is a summary of measurements planned for the coming year.

  12. High-voltage pixel sensors for ATLAS upgrade

    NASA Astrophysics Data System (ADS)

    Perić, I.; Kreidl, C.; Fischer, P.; Bompard, F.; Breugnon, P.; Clemens, J.-C.; Fougeron, D.; Liu, J.; Pangaud, P.; Rozanov, A.; Barbero, M.; Feigl, S.; Capeans, M.; Ferrere, D.; Pernegger, H.; Ristic, B.; Muenstermann, D.; Gonzalez Sevilla, S.; La Rosa, A.; Miucci, A.; Nessi, M.; Iacobucci, G.; Backhaus, M.; Hügging, Fabian; Krüger, H.; Hemperek, T.; Obermann, T.; Wermes, N.; Garcia-Sciveres, M.; Quadt, A.; Weingarten, J.; George, M.; Grosse-Knetter, J.; Rieger, J.; Bates, R.; Blue, A.; Buttar, C.; Hynds, D.

    2014-11-01

    The high-voltage (HV-) CMOS pixel sensors offer several good properties: a fast charge collection by drift, the possibility to implement relatively complex CMOS in-pixel electronics and the compatibility with commercial processes. The sensor element is a deep n-well diode in a p-type substrate. The n-well contains CMOS pixel electronics. The main charge collection mechanism is drift in a shallow, high field region, which leads to a fast charge collection and a high radiation tolerance. We are currently evaluating the use of the high-voltage detectors implemented in 180 nm HV-CMOS technology for the high-luminosity ATLAS upgrade. Our approach is replacing the existing pixel and strip sensors with the CMOS sensors while keeping the presently used readout ASICs. By intelligence we mean the ability of the sensor to recognize a particle hit and generate the address information. In this way we could benefit from the advantages of the HV sensor technology such as lower cost, lower mass, lower operating voltage, smaller pitch, smaller clusters at high incidence angles. Additionally we expect to achieve a radiation hardness necessary for ATLAS upgrade. In order to test the concept, we have designed two HV-CMOS prototypes that can be readout in two ways: using pixel and strip readout chips. In the case of the pixel readout, the connection between HV-CMOS sensor and the readout ASIC can be established capacitively.

  13. Frequency distribution signatures and classification of within-object pixels

    PubMed Central

    Stow, Douglas A.; Toure, Sory I.; Lippitt, Christopher D.; Lippitt, Caitlin L.; Lee, Chung-rui

    2011-01-01

    The premise of geographic object-based image analysis (GEOBIA) is that image objects are composed of aggregates of pixels that correspond to earth surface features of interest. Most commonly, image-derived objects (segments) or objects associated with predefined land units (e.g., agricultural fields) are classified using parametric statistical characteristics (e.g., mean and standard deviation) of the within-object pixels. The objective of this exploratory study was to examine the between- and within-class variability of frequency distributions of multispectral pixel values, and to evaluate a quantitative measure and classification rule that exploits the full pixel frequency distribution of within object pixels (i.e., histogram signatures) compared to simple parametric statistical characteristics. High spatial resolution Quickbird satellite multispectral data of Accra, Ghana were evaluated in the context of mapping land cover and land use and socioeconomic status. Results show that image objects associated with land cover and land use types can have characteristic, non-normal frequency distributions (histograms). Signatures of most image objects tended to match closely the training signature of a single class or sub-class. Curve matching approaches to classifying multi-pixel frequency distributions were found to be slightly more effective than standard statistical classifiers based on a nearest neighbor classifier. PMID:22408575

  14. CMOS Active Pixel Sensor (APS) Imager for Scientific Applications

    NASA Astrophysics Data System (ADS)

    Ay, Suat U.; Lesser, Michael P.; Fossum, Eric R.

    2002-12-01

    A 512×512 CMOS Active Pixel Sensor (APS) imager has been designed, fabricate, and tested for frontside illumination suitable for use in astronomy specifically in telescope guider systems as a replacement of CCD chips. The imager features a high-speed differential analog readout, 15 μm pixel pitch, 75 % fill factor (FF), 62 dB dynamic range, 315Ke- pixel capacity, less than 0.25% fixed pattern noise (FPN), 45 dB signal to noise ratio (SNR) and frame rate of up to 40 FPS. Design was implemented in a standard 0.5 μm CMOS process technology consuming less than 200mWatts on a single 5 Volt power supply. CMOS Active Pixel Sensor (APS) imager was developed with pixel structure suitable for both frontside and backside illumination holding large number of electron in relatively small pixel pitch of 15 μm. High-speed readout and signal processing circuits were designed to achieve low fixed pattern noise (FPN) and non-uniformity to provide CCD-like analog outputs. Target spectrum range of operation for the imager is in near ultraviolet (300-400 nm) with high quantum efficiency. This device is going to be used as a test vehicle to develop backside-thinning process.

  15. High frame rate measurements of semiconductor pixel detector readout IC

    NASA Astrophysics Data System (ADS)

    Szczygiel, R.; Grybos, P.; Maj, P.

    2012-07-01

    We report on high count rate and high frame rate measurements of a prototype IC named FPDR90, designed for readouts of hybrid pixel semiconductor detectors used for X-ray imaging applications. The FPDR90 is constructed in 90 nm CMOS technology and has dimensions of 4 mm×4 mm. Its main part is a matrix of 40×32 pixels with 100 μm×100 μm pixel size. The chip works in the single photon counting mode with two discriminators and two 16-bit ripple counters per pixel. The count rate per pixel depends on the effective CSA feedback resistance and can be set up to 6 Mcps. The FPDR90 can operate in the continuous readout mode, with zero dead time. Due to the architecture of digital blocks in pixel, one can select the number of bits read out from each counter from 1 to 16. Because in the FPDR90 prototype only one data output is available, the frame rate is 9 kfps and 72 kfps for 16 bits and 1 bit readout, respectively (with nominal clock frequency of 200 MHz).

  16. Preliminary investigations of active pixel sensors in Nuclear Medicine imaging

    NASA Astrophysics Data System (ADS)

    Ott, Robert; Evans, Noel; Evans, Phil; Osmond, J.; Clark, A.; Turchetta, R.

    2009-06-01

    Three CMOS active pixel sensors have been investigated for their application to Nuclear Medicine imaging. Startracker with 525×525 25 μm square pixels has been coupled via a fibre optic stud to a 2 mm thick segmented CsI(Tl) crystal. Imaging tests were performed using 99mTc sources, which emit 140 keV gamma rays. The system was interfaced to a PC via FPGA-based DAQ and optical link enabling imaging rates of 10 f/s. System noise was measured to be >100e and it was shown that the majority of this noise was fixed pattern in nature. The intrinsic spatial resolution was measured to be ˜80 μm and the system spatial resolution measured with a slit was ˜450 μm. The second sensor, On Pixel Intelligent CMOS (OPIC), had 64×72 40 μm pixels and was used to evaluate noise characteristics and to develop a method of differentiation between fixed pattern and statistical noise. The third sensor, Vanilla, had 520×520 25 μm pixels and a measured system noise of ˜25e. This sensor was coupled directly to the segmented phosphor. Imaging results show that even at this lower level of noise the signal from 140 keV gamma rays is small as the light from the phosphor is spread over a large number of pixels. Suggestions for the 'ideal' sensor are made.

  17. Inter-pixel Size Variations as Source of Spitzer Systematics

    NASA Astrophysics Data System (ADS)

    Himes, Michael David; Harrington, Joseph; Lust, Nathaniel B.

    2016-10-01

    In the astrophysical sciences imaging devices are commonly assumed to contain evenly sized pixels, with each pixel converting light to signal with a slightly different efficiency. These variations are accounted for by exposing the detector to a uniform light source and comparing each value to the mean of the exposure and dividing by the result (flatfielding) . If the detector instead had pixels which varied in size, the same variations to uniform illumination would be recorded and subsequently removed. However, in the presence of a flux gradient such as a star, the flatfielding will alter these flux values which in turn affects any analysis of the data. This alteration would be due to varying size pixels being corrected to a unit area through the flatfield, when the pixels themselves rightfully record a non-uniform area of the point-spread function (PSF). We believe that this may be the source of Spitzer's systematic error attributed to gain variations. We demonstrate what an imaging device with inter-pixel size differences looks like from a data standpoint, its effects on estimating the widths of a point source, and investigations to properly account for size variations without altering flux values.

  18. Challenges of small-pixel infrared detectors: a review

    NASA Astrophysics Data System (ADS)

    Rogalski, A.; Martyniuk, P.; Kopytko, M.

    2016-04-01

    In the last two decades, several new concepts for improving the performance of infrared detectors have been proposed. These new concepts particularly address the drive towards the so-called high operating temperature focal plane arrays (FPAs), aiming to increase detector operating temperatures, and as a consequence reduce the cost of infrared systems. In imaging systems with the above megapixel formats, pixel dimension plays a crucial role in determining critical system attributes such as system size, weight and power consumption (SWaP). The advent of smaller pixels has also resulted in the superior spatial and temperature resolution of these systems. Optimum pixel dimensions are limited by diffraction effects from the aperture, and are in turn wavelength-dependent. In this paper, the key challenges in realizing optimum pixel dimensions in FPA design including dark current, pixel hybridization, pixel delineation, and unit cell readout capacity are outlined to achieve a sufficiently adequate modulation transfer function for the ultra-small pitches involved. Both photon and thermal detectors have been considered. Concerning infrared photon detectors, the trade-offs between two types of competing technology—HgCdTe material systems and III-V materials (mainly barrier detectors)—have been investigated.

  19. Polycrystalline CVD diamond pixel array detector for nuclear particles monitoring

    NASA Astrophysics Data System (ADS)

    Pacilli, M.; Allegrini, P.; Girolami, M.; Conte, G.; Spiriti, E.; Ralchenko, V. G.; Komlenok, M. S.; Khomic, A. A.; Konov, V. I.

    2013-02-01

    We report the 90Sr beta response of a polycrystalline diamond pixel detector fabricated using metal-less graphitic ohmic contacts. Laser induced graphitization was used to realize multiple squared conductive contacts with 1mm × 1mm area, 0.2 mm apart, on one detector side while on the other side, for biasing, a 9mm × 9mm large graphite contact was realized. A proximity board was used to wire bonding nine pixels at a time and evaluate the charge collection homogeneity among the 36 detector pixels. Different configurations of biasing were experimented to test the charge collection and noise performance: connecting the pixel at the ground potential of the charge amplifier led to best results and minimum noise pedestal. The expected exponential trend typical of beta particles has been observed. Reversing the bias polarity the pulse height distribution (PHD) does not changes and signal saturation of any pixel was observed around ±200V (0.4 V/μm). Reasonable pixels response uniformity has been evidenced even if smaller pitch 50÷100 μm structures need to be tested.

  20. Active pixel sensor having intra-pixel charge transfer with analog-to-digital converter

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra K. (Inventor); Pain, Bedabrata (Inventor); Nixon, Robert H. (Inventor); Zhou, Zhimin (Inventor)

    2003-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node and an analog-to-digital converter formed in the substrate connected to the output of the readout circuit.

  1. Active pixel sensor having intra-pixel charge transfer with analog-to-digital converter

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra K. (Inventor); Pain, Bedabrata (Inventor); Nixon, Robert H. (Inventor); Zhou, Zhimin (Inventor)

    2000-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor Integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node and an analog-to-digital converter formed in the substrate connected to the output of the readout circuit.

  2. DRS uncooled VOx infrared detector development and production status

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Han, C. J.; Skidmore, George D.; Hess, Cory

    2010-04-01

    Significant progress has been made over the past decade on uncooled focal plane array (UFPA) technology development and production capacity at DRS as well as other domestic and overseas suppliers. This resulted in the proliferation of uncooled IR detectors in commercial and military markets. The uncooled detectors are widely used in firefighting, surveillance, industrial process monitoring, machine vision, and medical applications. In the military arena, uncooled detectors are fielded among diverse systems such as weapon sights, driver enhancement viewers, helmet-mounted sights, airborne and ground surveillance sensors including UAVs and robot vehicles. Pixel dimensions have continually decreased with an increase in pixel performance. This paper presents an overview of the DRS 25- and 17-micron pixel pitch uncooled VOx detector technology development and production status. The DRS uncooled FPA products include 320x240 and 640x480 arrays while the larger 1024x768 17-micron pitch array is at engineering prototype quantities. Current production of the 25-micron pitch 320x240 and 640x480 arrays exceeds 5,000 units per month, supporting U.S. military systems such as Army thermal weapon sights (TWS) and driver vision enhancers (DVE). Next generation systems are moving towards the 17-micron pixel pitch detectors. Advancement in small pixel technology has enabled the 17-micron pitch detectors performance to surpass their 25-micron pitch counterparts. To meet future production demand of the 17-micron pitch UFPAs, DRS has made significant investment in production infrastructure to upgrade its tools. These investments include a new DUV stepper, coater, and plasma etcher plus improvements in its manufacturing techniques to enhance yield. These advanced tools reduce the minimum line width in production below 0.35μm and are now being used to manufacture the 17-micron 320x240 and 640x480 arrays. To further technology development, DRS continues to engage in R&D activities

  3. Introducing sub-wavelength pixel THz camera for the understanding of close pixel-to-wavelength imaging challenges

    NASA Astrophysics Data System (ADS)

    Bergeron, A.; Marchese, L.; Bolduc, M.; Terroux, M.; Dufour, D.; Savard, E.; Tremblay, B.; Oulachgar, H.; Doucet, M.; Le Noc, L.; Alain, C.; Jerominek, H.

    2012-06-01

    Conventional guidelines and approximations useful in macro-scale system design can become invalidated when applied to the smaller scales. An illustration of this is when camera pixel size becomes smaller than the diffraction-limited resolution of the incident light. It is sometimes believed that there is no benefit in having a pixel width smaller than the resolving limit defined by the Raleigh criterion, 1.22 λ F/#. Though this rarely occurs in today's imaging technology, terahertz (THz) imaging is one emerging area where the pixel dimensions can be made smaller than the imaging wavelength. With terahertz camera technology, we are able to achieve sub-wavelength pixel sampling pitch, and therefore capable of directly measuring if there are image quality benefits to be derived from sub-wavelength sampling. Interest in terahertz imaging is high due to potential uses in security applications because of the greater penetration depth of terahertz radiation compared to the infrared and the visible. This paper discusses the modification by INO of its infrared MEMS microbolometer detector technology toward a THz imaging platform yielding a sub-wavelength pixel THz camera. Images obtained with this camera are reviewed in this paper. Measurements were also obtained using microscanning to increase sampling resolution. Parameters such as imaging resolution and sampling are addressed. A comparison is also made with results obtained with an 8-12 μm band camera having a pixel pitch close to the diffractionlimit.

  4. VeloPix: the pixel ASIC for the LHCb upgrade

    NASA Astrophysics Data System (ADS)

    Poikela, T.; De Gaspari, M.; Plosila, J.; Westerlund, T.; Ballabriga, R.; Buytaert, J.; Campbell, M.; Llopart, X.; Wyllie, K.; Gromov, V.; van Beuzekom, M.; Zivkovic, V.

    2015-01-01

    The LHCb Vertex Detector (VELO) will be upgraded in 2018 along with the other subsystems of LHCb in order to enable full readout at 40 MHz, with the data fed directly to the software triggering algorithms. The upgraded VELO is a lightweight hybrid pixel detector operating in vacuum in close proximity to the LHC beams. The readout will be provided by a dedicated front-end ASIC, dubbed VeloPix, matched to the LHCb readout requirements and the 55 × 55 μm VELO pixel dimensions. The chip is closely related to the Timepix3, from the Medipix family of ASICs. The principal challenge that the chip has to meet is a hit rate of up to 900 Mhits/s, resulting in a required output bandwidth of more than 16 Gbit/s. The occupancy across the chip is also very non-uniform, and the radiation levels reach an integrated 400 Mrad over the lifetime of the detector.VeloPix is a binary pixel readout chip with a data driven readout, designed in 130 nm CMOS technology. The pixels are combined into groups of 2 × 4 super pixels, enabling a shared logic and a reduction of bandwidth due to combined address and time stamp information. The pixel hits are combined with other simultaneous hits in the same super pixel, time stamped, and immediately driven off-chip. The analog front-end must be sufficiently fast to accurately time stamp the data, with a small enough dead time to minimize data loss in the most occupied regions of the chip. The data is driven off chip with a custom designed high speed serialiser. The current status of the ASIC design, the chip architecture and the simulations will be described.

  5. Level-1 pixel based tracking trigger algorithm for LHC upgrade

    NASA Astrophysics Data System (ADS)

    Moon, C.-S.; Savoy-Navarro, A.

    2015-10-01

    The Pixel Detector is the innermost detector of the tracking system of the Compact Muon Solenoid (CMS) experiment at CERN Large Hadron Collider (LHC) . It precisely determines the interaction point (primary vertex) of the events and the possible secondary vertexes due to heavy flavours (b and c quarks); it is part of the overall tracking system that allows reconstructing the tracks of the charged particles in the events and combined with the magnetic field to measure their momentum. The pixel detector allows measuring the tracks in the region closest to the interaction point. The Level-1 (real-time) pixel based tracking trigger is a novel trigger system that is currently being studied for the LHC upgrade. An important goal is developing real-time track reconstruction algorithms able to cope with very high rates and high flux of data in a very harsh environment. The pixel detector has an especially crucial role in precisely identifying the primary vertex of the rare physics events from the large pile-up (PU) of events. The goal of adding the pixel information already at the real-time level of the selection is to help reducing the total level-1 trigger rate while keeping an high selection capability. This is quite an innovative and challenging objective for the experiments upgrade for the High Luminosity LHC (HL-LHC) . The special case here addressed is the CMS experiment. This document describes exercises focusing on the development of a fast pixel track reconstruction where the pixel track matches with a Level-1 electron object using a ROOT-based simulation framework.

  6. Smart pixel imaging with computational-imaging arrays

    NASA Astrophysics Data System (ADS)

    Fernandez-Cull, Christy; Tyrrell, Brian M.; D'Onofrio, Richard; Bolstad, Andrew; Lin, Joseph; Little, Jeffrey W.; Blackwell, Megan; Renzi, Matthew; Kelly, Mike

    2014-07-01

    Smart pixel imaging with computational-imaging arrays (SPICA) transfers image plane coding typically realized in the optical architecture to the digital domain of the focal plane array, thereby minimizing signal-to-noise losses associated with static filters or apertures and inherent diffraction concerns. MIT Lincoln Laboratory has been developing digitalpixel focal plane array (DFPA) devices for many years. In this work, we leverage legacy designs modified with new features to realize a computational imaging array (CIA) with advanced pixel-processing capabilities. We briefly review the use of DFPAs for on-chip background removal and image plane filtering. We focus on two digital readout integrated circuits (DROICS) as CIAs for two-dimensional (2D) transient target tracking and three-dimensional (3D) transient target estimation using per-pixel coded-apertures or flutter shutters. This paper describes two DROICs - a SWIR pixelprocessing imager (SWIR-PPI) and a Visible CIA (VISCIA). SWIR-PPI is a DROIC with a 1 kHz global frame rate with a maximum per-pixel shuttering rate of 100 MHz, such that each pixel can be modulated by a time-varying, pseudorandom, and duo-binary signal (+1,-1,0). Combining per-pixel time-domain coding and processing enables 3D (x,y,t) target estimation with limited loss of spatial resolution. We evaluate structured and pseudo-random encoding strategies and employ linear inversion and non-linear inversion using total-variation minimization to estimate a 3D data cube from a single 2D temporally-encoded measurement. The VISCIA DROIC, while low-resolution, has a 6 kHz global frame rate and simultaneously encodes eight periodic or aperiodic transient target signatures at a maximum rate of 50 MHz using eight 8-bit counters. By transferring pixel-based image plane coding to the DROIC and utilizing sophisticated processing, our CIAs enable on-chip temporal super-resolution.

  7. Super pixel density based clustering automatic image classification method

    NASA Astrophysics Data System (ADS)

    Xu, Mingxing; Zhang, Chuan; Zhang, Tianxu

    2015-12-01

    The image classification is an important means of image segmentation and data mining, how to achieve rapid automated image classification has been the focus of research. In this paper, based on the super pixel density of cluster centers algorithm for automatic image classification and identify outlier. The use of the image pixel location coordinates and gray value computing density and distance, to achieve automatic image classification and outlier extraction. Due to the increased pixel dramatically increase the computational complexity, consider the method of ultra-pixel image preprocessing, divided into a small number of super-pixel sub-blocks after the density and distance calculations, while the design of a normalized density and distance discrimination law, to achieve automatic classification and clustering center selection, whereby the image automatically classify and identify outlier. After a lot of experiments, our method does not require human intervention, can automatically categorize images computing speed than the density clustering algorithm, the image can be effectively automated classification and outlier extraction.

  8. Multiport solid-state imager characterization at variable pixel rates

    SciTech Connect

    Yates, G.J.; Albright, K.A.; Turko, B.T.

    1993-08-01

    The imaging performance of an 8-port Full Frame Transfer Charge Coupled Device (FFT CCD) as a function of several parameters including pixel clock rate is presented. The device, model CCD- 13, manufactured by English Electric Valve (EEV) is a 512 {times} 512 pixel array designed with four individual programmable bidirectional serial registers and eight output amplifiers permitting simultaneous readout of eight segments (128 horizontal {times} 256 vertical pixels) of the array. The imager was evaluated in Los Alamos National Laboratory`s High-Speed Solid-State Imager Test Station at true pixel rates as high as 50 MHz for effective imager pixel rates approaching 400 MHz from multiporting. Key response characteristics measured include absolute responsivity, Charge-Transfer-Efficiency (CTE), dynamic range, resolution, signal-to-noise ratio, and electronic and optical crosstalk among the eight video channels. Preliminary test results and data obtained from the CCD-13 will be presented and the versatility/capabilities of the test station will be reviewed.

  9. Pixel classification based color image segmentation using quaternion exponent moments.

    PubMed

    Wang, Xiang-Yang; Wu, Zhi-Fang; Chen, Liang; Zheng, Hong-Liang; Yang, Hong-Ying

    2016-02-01

    Image segmentation remains an important, but hard-to-solve, problem since it appears to be application dependent with usually no a priori information available regarding the image structure. In recent years, many image segmentation algorithms have been developed, but they are often very complex and some undesired results occur frequently. In this paper, we propose a pixel classification based color image segmentation using quaternion exponent moments. Firstly, the pixel-level image feature is extracted based on quaternion exponent moments (QEMs), which can capture effectively the image pixel content by considering the correlation between different color channels. Then, the pixel-level image feature is used as input of twin support vector machines (TSVM) classifier, and the TSVM model is trained by selecting the training samples with Arimoto entropy thresholding. Finally, the color image is segmented with the trained TSVM model. The proposed scheme has the following advantages: (1) the effective QEMs is introduced to describe color image pixel content, which considers the correlation between different color channels, (2) the excellent TSVM classifier is utilized, which has lower computation time and higher classification accuracy. Experimental results show that our proposed method has very promising segmentation performance compared with the state-of-the-art segmentation approaches recently proposed in the literature.

  10. PIXSCAN: Pixel detector CT-scanner for small animal imaging

    NASA Astrophysics Data System (ADS)

    Delpierre, P.; Debarbieux, F.; Basolo, S.; Berar, J. F.; Bonissent, A.; Boudet, N.; Breugnon, P.; Caillot, B.; Cassol Brunner, F.; Chantepie, B.; Clemens, J. C.; Dinkespiler, B.; Khouri, R.; Koudobine, I.; Mararazzo, V.; Meessen, C.; Menouni, M.; Morel, C.; Mouget, C.; Pangaud, P.; Peyrin, F.; Rougon, G.; Sappey-Marinier, D.; Valton, S.; Vigeolas, E.

    2007-02-01

    The PIXSCAN is a small animal CT-scanner based on hybrid pixel detectors. These detectors provide very large dynamic range of photons counting at very low detector noise. They also provide high counting rates with fast image readout. Detection efficiency can be optimized by selecting the sensor medium according to the working energy range. Indeed, the use of CdTe allows a detection efficiency of 100% up to 50 keV. Altogether these characteristics are expected to improve the contrast of the CT-scanner, especially for soft tissues, and to reduce both the scan duration and the absorbed dose. A proof of principle has been performed by assembling into a PIXSCAN-XPAD2 prototype the photon counting pixel detector initially built for detection of X-ray synchrotron radiations. Despite the relatively large pixel size of this detector (330×330 μm 2), we can present three-dimensional tomographic reconstruction of mice at good contrast and spatial resolution. A new photon counting chip (XPAD3) is designed in sub-micronique technology to achieve 130×130 μm 2 pixels. This improved circuit has been equipped with an energy selection circuit to act as a band-pass emission filter. Furthermore, the PIXSCAN-XPAD3 hybrid pixel detectors will be combined with the Lausanne ClearPET scanner demonstrator. CT image reconstruction in this non-conventional geometry is under study for this purpose.

  11. Pixel classification based color image segmentation using quaternion exponent moments.

    PubMed

    Wang, Xiang-Yang; Wu, Zhi-Fang; Chen, Liang; Zheng, Hong-Liang; Yang, Hong-Ying

    2016-02-01

    Image segmentation remains an important, but hard-to-solve, problem since it appears to be application dependent with usually no a priori information available regarding the image structure. In recent years, many image segmentation algorithms have been developed, but they are often very complex and some undesired results occur frequently. In this paper, we propose a pixel classification based color image segmentation using quaternion exponent moments. Firstly, the pixel-level image feature is extracted based on quaternion exponent moments (QEMs), which can capture effectively the image pixel content by considering the correlation between different color channels. Then, the pixel-level image feature is used as input of twin support vector machines (TSVM) classifier, and the TSVM model is trained by selecting the training samples with Arimoto entropy thresholding. Finally, the color image is segmented with the trained TSVM model. The proposed scheme has the following advantages: (1) the effective QEMs is introduced to describe color image pixel content, which considers the correlation between different color channels, (2) the excellent TSVM classifier is utilized, which has lower computation time and higher classification accuracy. Experimental results show that our proposed method has very promising segmentation performance compared with the state-of-the-art segmentation approaches recently proposed in the literature. PMID:26618250

  12. Method and apparatus of high dynamic range image sensor with individual pixel reset

    NASA Technical Reports Server (NTRS)

    Yadid-Pecht, Orly (Inventor); Pain, Bedabrata (Inventor); Fossum, Eric R. (Inventor)

    2001-01-01

    A wide dynamic range image sensor provides individual pixel reset to vary the integration time of individual pixels. The integration time of each pixel is controlled by column and row reset control signals which activate a logical reset transistor only when both signals coincide for a given pixel.

  13. Virus based Full Colour Pixels using a Microheater.

    PubMed

    Kim, Won-Geun; Kim, Kyujung; Ha, Sung-Hun; Song, Hyerin; Yu, Hyun-Woo; Kim, Chuntae; Kim, Jong-Man; Oh, Jin-Woo

    2015-01-01

    Mimicking natural structures has been received considerable attentions, and there have been a few practical advances. Tremendous efforts based on a self-assembly technique have been contributed to the development of the novel photonic structures which are mimicking nature's inventions. We emulate the photonic structures from an origin of colour generation of mammalian skins and avian skin/feathers using M13 phage. The structures can be generated a full range of RGB colours that can be sensitively switched by temperature and substrate materials. Consequently, we developed an M13 phage-based temperature-dependent actively controllable colour pixels platform on a microheater chip. Given the simplicity of the fabrication process, the low voltage requirements and cycling stability, the virus colour pixels enable us to substitute for conventional colour pixels for the development of various implantable, wearable and flexible devices in future. PMID:26334322

  14. Leakage current measurements of a pixelated polycrystalline CVD diamond detector

    NASA Astrophysics Data System (ADS)

    Zain, R. M.; Maneuski, D.; O'Shea, V.; Bates, R.; Blue, A.; Cunnigham, L.; Stehl, C.; Berderman, E.; Rahim, R. A.

    2013-01-01

    Diamond has several desirable features when used as a material for radiation detection. With the invention of synthetic growth techniques, it has become feasible to look at developing diamond radiation detectors with reasonable surface areas. Polycrystalline diamond has been grown using a chemical vapour deposition (CVD) technique by the University of Augsburg and detector structures fabricated at the James Watt Nanofabrication Centre (JWNC) in the University of Glasgow in order to produce pixelated detector arrays. The anode and cathode contacts are realised by depositing gold to produce ohmic contacts. Measurements of I-V characteristics were performed to study the material uniformity. The bias voltage is stepped from -1000V to 1000V to investigate the variation of leakage current from pixel to pixel. Bulk leakage current is measured to be less than 1nA.

  15. Calibration analysis software for the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Stramaglia, Maria Elena

    2016-07-01

    The calibration of the ATLAS Pixel Detector at LHC fulfils two main purposes: to tune the front-end configuration parameters for establishing the best operational settings and to measure the tuning performance through a subset of scans. An analysis framework has been set up in order to take actions on the detector given the outcome of a calibration scan (e.g. to create a mask for disabling noisy pixels). The software framework to control all aspects of the Pixel Detector scans and analyses is called calibration console. The introduction of a new layer, equipped with new FE-I4 chips, required an update of the console architecture. It now handles scans and scan analyses applied together to chips with different characteristics. An overview of the newly developed calibration analysis software will be presented, together with some preliminary results.

  16. Depleted CMOS pixels for LHC proton-proton experiments

    NASA Astrophysics Data System (ADS)

    Wermes, N.

    2016-07-01

    While so far monolithic pixel detectors have remained in the realm of comparatively low rate and radiation applications outside LHC, new developments exploiting high resistivity substrates with three or four well CMOS process options allow reasonably large depletion depths and full CMOS circuitry in a monolithic structure. This opens up the possibility to target CMOS pixel detectors also for high radiation pp-experiments at the LHC upgrade, either in a hybrid-type fashion or even fully monolithic. Several pixel matrices have been prototyped with high ohmic substrates, high voltage options, and full CMOS electronics. They were characterized in the lab and in test beams. An overview of the necessary development steps and different approaches as well as prototype results are presented in this paper.

  17. Introducing a 384x288 pixel terahertz camera core

    NASA Astrophysics Data System (ADS)

    Chevalier, C.; Mercier, L.,; Duchesne, F.; Gagnon, L.; Tremblay, B.; Terroux, M.; Généreux, F.; Paultre, J.-E.; Provençal, F.; Desroches, Y.; Marchese, L.; Jerominek, H.; Alain, C.; Bergeron, A.

    2013-03-01

    Terahertz is a field in expansion with the emergence of various security needs such as parcel inspection and through-camouflage vision. Terahertz wavebands are characterized by long wavelengths compared to the traditional infrared and visible spectra. However, it has recently been demonstrated that a 52 μm pixel pitch microscanned down to an efficient sampling pitch of 26 μm could provide useful information even using a 118.83 μm wavelength. With this in mind, INO has developed a terahertz camera core based on a 384x288 pixel 35 μm pixel pitch uncooled bolometric terahertz detector. The camera core provides full 16-bit output video rate.

  18. Virus based Full Colour Pixels using a Microheater

    NASA Astrophysics Data System (ADS)

    Kim, Won-Geun; Kim, Kyujung; Ha, Sung-Hun; Song, Hyerin; Yu, Hyun-Woo; Kim, Chuntae; Kim, Jong-Man; Oh, Jin-Woo

    2015-09-01

    Mimicking natural structures has been received considerable attentions, and there have been a few practical advances. Tremendous efforts based on a self-assembly technique have been contributed to the development of the novel photonic structures which are mimicking nature’s inventions. We emulate the photonic structures from an origin of colour generation of mammalian skins and avian skin/feathers using M13 phage. The structures can be generated a full range of RGB colours that can be sensitively switched by temperature and substrate materials. Consequently, we developed an M13 phage-based temperature-dependent actively controllable colour pixels platform on a microheater chip. Given the simplicity of the fabrication process, the low voltage requirements and cycling stability, the virus colour pixels enable us to substitute for conventional colour pixels for the development of various implantable, wearable and flexible devices in future.

  19. Planar pixel sensors for the ATLAS upgrade: beam tests results

    NASA Astrophysics Data System (ADS)

    Weingarten, J.; Altenheiner, S.; Beimforde, M.; Benoit, M.; Bomben, M.; Calderini, G.; Gallrapp, C.; George, M.; Gibson, S.; Grinstein, S.; Janoska, Z.; Jentzsch, J.; Jinnouchi, O.; Kishida, T.; La Rosa, A.; Libov, V.; Macchiolo, A.; Marchiori, G.; Muenstermann, D.; Nagai, R.; Piacquadio, G.; Ristic, B.; Rubinskiy, I.; Rummler, A.; Takubo, Y.; Troska, G.; Tsiskaridtze, S.; Tsurin, I.; Unno, Y.; Weigell, P.; Wittig, T.

    2012-10-01

    The performance of planar silicon pixel sensors, in development for the ATLAS Insertable B-Layer and High Luminosity LHC (HL-LHC) upgrades, has been examined in a series of beam tests at the CERN SPS facilities since 2009. Salient results are reported on the key parameters, including the spatial resolution, the charge collection and the charge sharing between adjacent cells, for different bulk materials and sensor geometries. Measurements are presented for n+-in-n pixel sensors irradiated with a range of fluences and for p-type silicon sensors with various layouts from different vendors. All tested sensors were connected via bump-bonding to the ATLAS Pixel read-out chip. The tests reveal that both n-type and p-type planar sensors are able to collect significant charge even after the lifetime fluence expected at the HL-LHC.

  20. Virus based Full Colour Pixels using a Microheater

    PubMed Central

    Kim, Won-Geun; Kim, Kyujung; Ha, Sung-Hun; Song, Hyerin; Yu, Hyun-Woo; Kim, Chuntae; Kim, Jong-Man; Oh, Jin-Woo

    2015-01-01

    Mimicking natural structures has been received considerable attentions, and there have been a few practical advances. Tremendous efforts based on a self-assembly technique have been contributed to the development of the novel photonic structures which are mimicking nature’s inventions. We emulate the photonic structures from an origin of colour generation of mammalian skins and avian skin/feathers using M13 phage. The structures can be generated a full range of RGB colours that can be sensitively switched by temperature and substrate materials. Consequently, we developed an M13 phage-based temperature-dependent actively controllable colour pixels platform on a microheater chip. Given the simplicity of the fabrication process, the low voltage requirements and cycling stability, the virus colour pixels enable us to substitute for conventional colour pixels for the development of various implantable, wearable and flexible devices in future. PMID:26334322

  1. Imaging by photon counting with 256x256 pixel matrix

    NASA Astrophysics Data System (ADS)

    Tlustos, Lukas; Campbell, Michael; Heijne, Erik H. M.; Llopart, Xavier

    2004-09-01

    Using 0.25µm standard CMOS we have developed 2-D semiconductor matrix detectors with sophisticated functionality integrated inside each pixel of a hybrid sensor module. One of these sensor modules is a matrix of 256x256 square 55µm pixels intended for X-ray imaging. This device is called 'Medipix2' and features a fast amplifier and two-level discrimination for signals between 1000 and 100000 equivalent electrons, with overall signal noise ~150 e- rms. Signal polarity and comparator thresholds are programmable. A maximum count rate of nearly 1 MHz per pixel can be achieved, which corresponds to an average flux of 3x10exp10 photons per cm2. The selected signals can be accumulated in each pixel in a 13-bit register. The serial readout takes 5-10 ms. A parallel readout of ~300 µs could also be used. Housekeeping functions such as local dark current compensation, test pulse generation, silencing of noisy pixels and threshold tuning in each pixel contribute to the homogeneous response over a large sensor area. The sensor material can be adapted to the energy of the X-rays. Best results have been obtained with high-resistivity silicon detectors, but also CdTe and GaAs detectors have been used. The lowest detectable X-ray energy was about 4 keV. Background measurements have been made, as well as measurements of the uniformity of imaging by photon counting. Very low photon count rates are feasible and noise-free at room temperature. The readout matrix can be used also with visible photons if an energy or charge intensifier structure is interposed such as a gaseous amplification layer or a microchannel plate or acceleration field in vacuum.

  2. Mapping Pixel Windows To Vectors For Parallel Processing

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.

    1996-01-01

    Mapping performed by matrices of transistor switches. Arrays of transistor switches devised for use in forming simultaneous connections from square subarray (window) of n x n pixels within electronic imaging device containing np x np array of pixels to linear array of n(sup2) input terminals of electronic neural network or other parallel-processing circuit. Method helps to realize potential for rapidity in parallel processing for such applications as enhancement of images and recognition of patterns. In providing simultaneous connections, overcomes timing bottleneck or older multiplexing, serial-switching, and sample-and-hold methods.

  3. CMOS VLSI Active-Pixel Sensor for Tracking

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata; Sun, Chao; Yang, Guang; Heynssens, Julie

    2004-01-01

    An architecture for a proposed active-pixel sensor (APS) and a design to implement the architecture in a complementary metal oxide semiconductor (CMOS) very-large-scale integrated (VLSI) circuit provide for some advanced features that are expected to be especially desirable for tracking pointlike features of stars. The architecture would also make this APS suitable for robotic- vision and general pointing and tracking applications. CMOS imagers in general are well suited for pointing and tracking because they can be configured for random access to selected pixels and to provide readout from windows of interest within their fields of view. However, until now, the architectures of CMOS imagers have not supported multiwindow operation or low-noise data collection. Moreover, smearing and motion artifacts in collected images have made prior CMOS imagers unsuitable for tracking applications. The proposed CMOS imager (see figure) would include an array of 1,024 by 1,024 pixels containing high-performance photodiode-based APS circuitry. The pixel pitch would be 9 m. The operations of the pixel circuits would be sequenced and otherwise controlled by an on-chip timing and control block, which would enable the collection of image data, during a single frame period, from either the full frame (that is, all 1,024 1,024 pixels) or from within as many as 8 different arbitrarily placed windows as large as 8 by 8 pixels each. A typical prior CMOS APS operates in a row-at-a-time ( grolling-shutter h) readout mode, which gives rise to exposure skew. In contrast, the proposed APS would operate in a sample-first/readlater mode, suppressing rolling-shutter effects. In this mode, the analog readout signals from the pixels corresponding to the windows of the interest (which windows, in the star-tracking application, would presumably contain guide stars) would be sampled rapidly by routing them through a programmable diagonal switch array to an on-chip parallel analog memory array. The

  4. The BTeV pixel detector and trigger system

    SciTech Connect

    Simon Kwan

    2002-12-03

    BTeV is an approved forward collider experiment at the Fermilab Tevatron dedicated to the precision studies of CP violation, mixing, and rare decays of beauty and charm hadrons. The BTeV detector has been designed to achieve these goals. One of the unique features of BTeV is a state-of-the-art pixel detector system, designed to provide accurate measurements of the decay vertices of heavy flavor hadrons that can be used in the first trigger level. The pixel vertex detector and the trigger design are described. Recent results on some of the achievements in the R and D effort are presented.

  5. Highly Reflective Multi-stable Electrofluidic Display Pixels

    NASA Astrophysics Data System (ADS)

    Yang, Shu

    Electronic papers (E-papers) refer to the displays that mimic the appearance of printed papers, but still owning the features of conventional electronic displays, such as the abilities of browsing websites and playing videos. The motivation of creating paper-like displays is inspired by the truths that reading on a paper caused least eye fatigue due to the paper's reflective and light diffusive nature, and, unlike the existing commercial displays, there is no cost of any form of energy for sustaining the displayed image. To achieve the equivalent visual effect of a paper print, an ideal E-paper has to be a highly reflective with good contrast ratio and full-color capability. To sustain the image with zero power consumption, the display pixels need to be bistable, which means the "on" and "off" states are both lowest energy states. Pixel can change its state only when sufficient external energy is given. There are many emerging technologies competing to demonstrate the first ideal E-paper device. However, none is able to achieve satisfactory visual effect, bistability and video speed at the same time. Challenges come from either the inherent physical/chemical properties or the fabrication process. Electrofluidic display is one of the most promising E-paper technologies. It has successfully demonstrated high reflectivity, brilliant color and video speed operation by moving colored pigment dispersion between visible and invisible places with electrowetting force. However, the pixel design did not allow the image bistability. Presented in this dissertation are the multi-stable electrofluidic display pixels that are able to sustain grayscale levels without any power consumption, while keeping the favorable features of the previous generation electrofluidic display. The pixel design, fabrication method using multiple layer dry film photoresist lamination, and physical/optical characterizations are discussed in details. Based on the pixel structure, the preliminary

  6. Sensor design for the ATLAS-pixel detector

    NASA Astrophysics Data System (ADS)

    Rohe, T.; Hügging, F.; Lutz, G.; Richter, R. H.; Wunstorf, R.

    1998-02-01

    The inner detector of the ATLAS experiment will contain three layers of pixel detectors. The first prototype of the sensor part will be an n +n-device in order to allow partial depleted operation after bulk inversion and a guard-ring scheme keeping the entire detector surface close to the electronic chip on ground potential. Further, a bias structure is introduced providing testability of the sensors before mounting them to the electronics. The design of the single pixel cell is the result of a detailed device simulation study.

  7. The BTeV pixel and microstrip detector

    SciTech Connect

    Simon W Kwan

    2003-06-04

    The BTeV pixel detector is one of the most crucial elements in the BTeV experiment. While the pixel detector is technically challenging, we have made great progress towards identifying viable solutions for individual components of the system. The forward silicon tracker is based on more mature technology and its design has benefited from the experience of other experiments. Nevertheless, we have started an R&D program on the forward silicon tracker and first results are expected some time next year.

  8. Development of a high density pixel multichip module at Fermilab

    SciTech Connect

    Cardoso, G.

    2001-03-08

    At Fermilab, both pixel detector multichip module and sensor hybridization are being developed for the BTeV experiment. The BTeV pixel detector is based on a design relying on a hybrid approach. With this approach, the readout chip and the sensor array are developed separately and the detector is constructed by flip-chip mating the two together. This method offers maximum flexibility in the development process, choice of fabrication technologies, and the choice of sensor material. This paper presents strategies to handle the required data rate and performance results of the first prototype and detector hybridization.

  9. Pixel multichip module design for a high energy physics experiment

    SciTech Connect

    Guilherme Cardoso et al.

    2003-11-05

    At Fermilab, a pixel detector multichip module is being developed for the BTeV experiment. The module is composed of three layers. The lowest layer is formed by the readout integrated circuits (ICs). The back of the ICs is in thermal contact with the supporting structure, while the top is flip-chip bump-bonded to the pixel sensor. A low mass flex-circuit interconnect is glued on the top of this assembly, and the readout IC pads are wire-bounded to the circuit. This paper presents recent results on the development of a multichip module prototype and summarizes its performance characteristics.

  10. Development of a high density pixel multichip module at Fermilab

    SciTech Connect

    Sergio Zimmermann et al.

    2001-09-11

    At Fermilab, a pixel detector multichip module is being developed for the BTeV experiment. The module is composed of three layers. The lowest layer is formed by the readout integrated circuits (ICs). The back of the ICs is in thermal contact with the supporting structure, while the top is flip-chip bump-bonded to the pixel sensor. A low mass flex-circuit interconnect is glued on the top of this assembly, and the readout IC pads are wire-bounded to the circuit. This paper presents recent results on the development of a multichip module prototype and summarizes its performance characteristics.

  11. Sub-pixel phase-measuring interferometry with interlace stitching

    NASA Technical Reports Server (NTRS)

    Mooney, James T.

    2005-01-01

    Measurement of mid spatial frequency figure error is critical to large precision optics for missions such as TPF-C. This presentation introduces a technique for increasing the spatial sampling resolution to meet these requirements using conventional video resolution phase-measuring interferometer. Technique involves sub-pixel data shifts, interlaced stitching and PSF deconvolution.

  12. The NUC and blind pixel eliminating in the DTDI application

    NASA Astrophysics Data System (ADS)

    Su, Xiao Feng; Chen, Fan Sheng; Pan, Sheng Da; Gong, Xue Yi; Dong, Yu Cui

    2013-12-01

    AS infrared CMOS Digital TDI (Time Delay and integrate) has a simple structure, excellent performance and flexible operation, it has been used in more and more applications. Because of the limitation of the Production process level, the plane array of the infrared detector has a large NU (non-uniformity) and a certain blind pixel rate. Both of the two will raise the noise and lead to the TDI works not very well. In this paper, for the impact of the system performance, the most important elements are analyzed, which are the NU of the optical system, the NU of the Plane array and the blind pixel in the Plane array. Here a reasonable algorithm which considers the background removal and the linear response model of the infrared detector is used to do the NUC (Non-uniformity correction) process, when the infrared detector array is used as a Digital TDI. In order to eliminate the impact of the blind pixel, the concept of surplus pixel method is introduced in, through the method, the SNR (signal to noise ratio) can be improved and the spatial and temporal resolution will not be changed. Finally we use a MWIR (Medium Ware Infrared) detector to do the experiment and the result proves the effectiveness of the method.

  13. Precision tracking with a single gaseous pixel detector

    NASA Astrophysics Data System (ADS)

    Tsigaridas, S.; van Bakel, N.; Bilevych, Y.; Gromov, V.; Hartjes, F.; Hessey, N. P.; de Jong, P.; Kluit, R.

    2015-09-01

    The importance of micro-pattern gaseous detectors has grown over the past few years after successful usage in a large number of applications in physics experiments and medicine. We develop gaseous pixel detectors using micromegas-based amplification structures on top of CMOS pixel readout chips. Using wafer post-processing we add a spark-protection layer and a grid to create an amplification region above the chip, allowing individual electrons released above the grid by the passage of ionising radiation to be recorded. The electron creation point is measured in 3D, using the pixel position for (x, y) and the drift time for z. The track can be reconstructed by fitting a straight line to these points. In this work we have used a pixel-readout-chip which is a small-scale prototype of Timepix3 chip (designed for both silicon and gaseous detection media). This prototype chip has several advantages over the existing Timepix chip, including a faster front-end (pre-amplifier and discriminator) and a faster TDC which reduce timewalk's contribution to the z position error. Although the chip is very small (sensitive area of 0.88 × 0.88mm2), we have built it into a detector with a short drift gap (1.3 mm), and measured its tracking performance in an electron beam at DESY. We present the results obtained, which lead to a significant improvement for the resolutions with respect to Timepix-based detectors.

  14. Transversal-readout CMOS active pixel image sensor

    NASA Astrophysics Data System (ADS)

    Miyatake, Shigehiro; Ishida, Kouichi; Morimoto, Takashi; Masaki, Yasuo; Tanabe, Hideki

    2001-05-01

    This paper presents a CMOS active pixel image sensor (APS) with a transversal readout architecture that eliminates the vertically striped fixed pattern noise (FPN). There are two kinds of FPNs for CMOS APSs. One originates form the pixel- to-pixel variation in dark current and source-follower threshold voltage, and the other from the column-to-column variation in column readout structures. The former may become invisible in the future due to process improvements. However, the latter, which result sin a vertically striped FPN, is and will be conspicuous without some subtraction because of the correlation in the vertical direction. The pixel consists of a photodiode, a row- and a column-reset transistor, a source follower input transistor, and a column-select transistor instead of the row-select transistor in conventional CMOS APSs. The column-select transistor is connected to a signal line, which runs horizontally instead of vertically. Every horizontal signal line is merged into a single vertical signal line via a row- select transistor, which can be made large enough to make its on-resistence variation negligible because of its low driving frequency. Therefore, the sensor has neither a vertical nor horizontal stripe FPN.

  15. High responsivity CMOS imager pixel implemented in SOI technology

    NASA Technical Reports Server (NTRS)

    Zheng, X.; Wrigley, C.; Yang, G.; Pain, B.

    2000-01-01

    Availability of mature sub-micron CMOS technology and the advent of the new low noise active pixel sensor (APS) concept have enabled the development of low power, miniature, single-chip, CMOS digital imagers in the decade of the 1990's.

  16. Pixel Analysis and Plasma Dynamics Characterized by Photospheric Spectral Data

    NASA Astrophysics Data System (ADS)

    Rasca, Anthony P.; Chen, James; Pevtsov, Alexei A.

    2016-05-01

    Recent observations of the photosphere using high spatial and temporal resolutions show small dynamic features at the resolving limit during emerging flux events. However, line-of-sight (LOS) magnetogram pixels only contain the net uncanceled magnetic flux, which is expected to increase for fixed regions as resolution limits improve. A new pixel dynamics method uses spectrographic images to characterize photospheric absorption line profiles by variations in line displacement, width, asymmetry, and peakedness and is applied to quiet-sun regions, active regions with no eruption, and an active region with an ongoing eruption. Using Stokes I images from SOLIS/VSM on 2012 March 13, variations in line width and peakedness of Fe I 6301.5 Å are shown to have a strong spatial and temporal relationship with an M7.9 X-ray flare originating from NOAA 11429. This relationship is observed as a flattening in the line profile as the X-ray flare approaches peak intensity and was not present in area scans of a non-eruptive active region on 2011 April 14. These results are used to estimate dynamic plasma properties on sub-pixel scales and provide both spatial and temporal information of sub-pixel activity at the photosphere. The analysis can be extended to include the full Stokes parameters and study signatures of magnetic fields and coupled plasma properties.

  17. The pixel tracking telescope at the Fermilab Test Beam Facility

    DOE PAGES

    Kwan, Simon; Lei, CM; Menasce, Dario; Moroni, Luigi; Ngadiuba, Jennifer; Prosser, Alan; Rivera, Ryan; Terzo, Stefano; Turqueti, Marcos; Uplegger, Lorenzo; et al

    2016-03-01

    An all silicon pixel telescope has been assembled and used at the Fermilab Test Beam Facility (FTBF) since 2009 to provide precise tracking information for different test beam experiments with a wide range of Detectors Under Test (DUTs) requiring high resolution measurement of the track impact point. The telescope is based on CMS pixel modules left over from the CMS forward pixel production. Eight planes are arranged to achieve a resolution of less than 8 μm on the 120 GeV proton beam transverse coordinate at the DUT position. In order to achieve such resolution with 100 × 150 μm2 pixelmore » cells, the planes were tilted to 25 degrees to maximize charge sharing between pixels. Crucial for obtaining this performance is the alignment software, called Monicelli, specifically designed and optimized for this system. This paper will describe the telescope hardware, the data acquisition system and the alignment software constituting this particle tracking system for test beam users.« less

  18. Experimental tests of a hybrid pixellated detector for gamma imaging

    NASA Astrophysics Data System (ADS)

    Gal, O.; Mikulec, B.; Million, M.

    2001-03-01

    In the framework of the MEDIPIX Collaboration, a hybrid pixel detector has been developed primarily for X-ray radiography. This detector consists of a 64×64 pixel photon counting chip (PCC), bump bonded to a 200 μm thick GaAs substrate. The PCC is optimised for energy depositions in the range of a few keV to a few tens of keV. The aim of this study is to evaluate the detector for applications in decommissioning of nuclear power plants where typical sources have energies in range of a few hundred keV. Tests were realised using a 137Cs gamma source (660 keV). At this energy, Monte-Carlo simulations predict that, on average, for more than 60% of primary interactions, there is at least one pixel on which the deposited energy exceeds 100 keV. Simulations also allow modelling of the spatial energy spreading. The comparison of the simulation results with experimental data should indicate if there is a significant contribution of electrical cross-coupling between pixels to the cluster size of the detected hits. The results obtained demonstrate promising perspectives for this kind of detector towards gamma imaging applications.

  19. Optimization of Focusing by Strip and Pixel Arrays

    SciTech Connect

    Burke, G J; White, D A; Thompson, C A

    2005-06-30

    Professor Kevin Webb and students at Purdue University have demonstrated the design of conducting strip and pixel arrays for focusing electromagnetic waves [1, 2]. Their key point was to design structures to focus waves in the near field using full wave modeling and optimization methods for design. Their designs included arrays of conducting strips optimized with a downhill search algorithm and arrays of conducting and dielectric pixels optimized with the iterative direct binary search method. They used a finite element code for modeling. This report documents our attempts to duplicate and verify their results. We have modeled 2D conducting strips and both conducting and dielectric pixel arrays with moment method and FDTD codes to compare with Webb's results. New designs for strip arrays were developed with optimization by the downhill simplex method with simulated annealing. Strip arrays were optimized to focus an incident plane wave at a point or at two separated points and to switch between focusing points with a change in frequency. We also tried putting a line current source at the focus point for the plane wave to see how it would work as a directive antenna. We have not tried optimizing the conducting or dielectric pixel arrays, but modeled the structures designed by Webb with the moment method and FDTD to compare with the Purdue results.

  20. Photovoltaic Pixels for Neural Stimulation: Circuit Models and Performance.

    PubMed

    Boinagrov, David; Lei, Xin; Goetz, Georges; Kamins, Theodore I; Mathieson, Keith; Galambos, Ludwig; Harris, James S; Palanker, Daniel

    2016-02-01

    Photovoltaic conversion of pulsed light into pulsed electric current enables optically-activated neural stimulation with miniature wireless implants. In photovoltaic retinal prostheses, patterns of near-infrared light projected from video goggles onto subretinal arrays of photovoltaic pixels are converted into patterns of current to stimulate the inner retinal neurons. We describe a model of these devices and evaluate the performance of photovoltaic circuits, including the electrode-electrolyte interface. Characteristics of the electrodes measured in saline with various voltages, pulse durations, and polarities were modeled as voltage-dependent capacitances and Faradaic resistances. The resulting mathematical model of the circuit yielded dynamics of the electric current generated by the photovoltaic pixels illuminated by pulsed light. Voltages measured in saline with a pipette electrode above the pixel closely matched results of the model. Using the circuit model, our pixel design was optimized for maximum charge injection under various lighting conditions and for different stimulation thresholds. To speed discharge of the electrodes between the pulses of light, a shunt resistor was introduced and optimized for high frequency stimulation.

  1. Sub-pixel localization of highways in AVIRIS images

    NASA Technical Reports Server (NTRS)

    Salu, Yehuda

    1995-01-01

    Roads and highways show up clearly in many bands of AVIRIS images. A typical lane in the U.S. is 12 feet wide, and the total width of a four lane highway, including 18 feet of paved shoulders, is 19.8 m. Such a highway will cover only a portion of any 20x20 m AVIRIS pixel that it traverses. The other portion of these pixels wil be usually covered by vegetation. An interesting problem is to precisely determine the location of a highway within the AVIRIS pixels that it traverses. This information may be used for alignment and spatial calibration of AVIRIS images. Also, since the reflection properties of highway surfaces do not change with time, and they can be determined once and for all, such information can be of help in calculating and filtering out the atmospheric noise that contaminates AVIRIS measurements. The purpose of this report is to describe a method for sub-pixel localization of highways.

  2. Silicon avalanche pixel sensor for high precision tracking

    NASA Astrophysics Data System (ADS)

    D'Ascenzo, N.; Marrocchesi, P. S.; Moon, C. S.; Morsani, F.; Ratti, L.; Saveliev, V.; Savoy Navarro, A.; Xie, Q.

    2014-03-01

    The development of an innovative position sensitive pixelated sensor to detect and measure with high precision the coordinates of the ionizing particles is proposed. The silicon avalanche pixel sensors (APiX) is based on the vertical integration of avalanche pixels connected in pairs and operated in coincidence in fully digital mode and with the processing electronics embedded on the chip. The APiX sensor addresses the need to minimize the material budget and related multiple scattering effects in tracking systems requiring a high spatial resolution in the presence of the large track occupancy. The expected operation of the new sensor features: low noise, low power consumption and suitable radiation tolerance. The APiX device provides on-chip digital information on the position of the coordinate of the impinging charged particle and can be seen as the building block of a modular system of pixelated arrays, implementing a sparsified readout. The technological challenges are the 3D integration of the device under CMOS processes and integration of processing electronics.

  3. Overview of the BTeV Pixel Detector

    SciTech Connect

    Jeffrey A Appel

    2002-12-10

    BTeV is a new Fermilab beauty and charm experiment designed to operate in the CZero region of the Tevatron collider. Critical to the success of BTeV is its pixel detector. The unique features of this pixel detector include its proximity to the beam, its operation with a beam crossing time of 132 ns, and the need for the detector information to be read out quickly enough to be used for the lowest level trigger. This talk presents an overview of the pixel detector design, giving the motivations for the technical choices made. The status of the current R&D on detector components is also reviewed. Additional Pixel 2002 talks on the BTeV pixel detector are given by Dave Christian[1], Mayling Wong[2], and Sergio Zimmermann[3]. Table 1 gives a selection of pixel detector parameters for the ALICE, ATLAS, BTeV, and CMS experiments. Comparing the progression of this table, which I have been updating for the last several years, has shown a convergence of specifications. Nevertheless, significant differences endure. The BTeV data-driven readout, horizontal and vertical position resolution better than 9 {micro}m with the {+-} 300 mr forward acceptance, and positioning in vacuum and as close as 6 mm from the circulating beams remain unique. These features are driven by the physics goals of the BTeV experiment. Table 2 demonstrates that the vertex trigger performance made possible by these features is requisite for a very large fraction of the B meson decay physics which is so central to the motivation for BTeV. For most of the physics quantities of interest listed in the table, the vertex trigger is essential. The performance of the BTeV pixel detector may be summarized by looking at particular physics examples; e.g., the B{sub s} meson decay B{sub s} {yields} D{sub s}{sup -} K{sup +}. For that decay, studies using GEANT3 simulations provide quantitative measures of performance. For example, the separation between the B{sub s} decay point and the primary proton

  4. Remote Sensing Classification Uncertainty: Validating Probabilistic Pixel Level Classification

    NASA Astrophysics Data System (ADS)

    Vrettas, Michail; Cornford, Dan; Bastin, Lucy; Pons, Xavier; Sevillano, Eva; Moré, Gerard; Serra, Pere; Ninyerola, Miquel

    2013-04-01

    There already exists an extensive literature on classification of remotely sensed imagery, and indeed classification more widely, that considers a wide range of probabilistic and non-probabilistic classification methodologies. Although for many probabilistic classification methodologies posterior class probabilities are produced per pixel (observation) these are often not communicated at the pixel level, and typically not validated at the pixel level. Most often the probabilistic classification in converted into a hard classification (of the most probable class) and the accuracy of the resulting classification is reported in terms of a global confusion matrix, or some score derived from this. For applications where classification accuracy is spatially variable and where pixel level estimates of uncertainty can be meaningfully exploited in workflows that propagate uncertainty validating and communicating the pixel level uncertainty opens opportunities for more refined and accountable modelling. In this work we describe our recent work applying and validation of a range of probabilistic classifiers. Using a multi-temporal Landsat data set of the Ebro Delta in Catalonia, which has been carefully radiometrically and geometrically corrected, we present a range of Bayesian classifiers from simple Bayesian linear discriminant analysis to a complex variational Gaussian process based classifier. Field study derived labelled data, classified into 8 classes, which primarily consider land use and the degree of flooding in what is a rice growing region, are used to train the pixel level classifiers. Our focus is not so much on the classification accuracy, but rather the validation of the probabilistic classification made by all methods. We present a range of validation plots and scores, many of which are used for probabilistic weather forecast verification, but are new to remote sensing classification including of course the standard measures of misclassification, but also

  5. Monolithic active pixel sensors (MAPS) in a VLSI CMOS technology

    NASA Astrophysics Data System (ADS)

    Turchetta, R.; French, M.; Manolopoulos, S.; Tyndel, M.; Allport, P.; Bates, R.; O'Shea, V.; Hall, G.; Raymond, M.

    2003-03-01

    Monolithic Active Pixel Sensors (MAPS) designed in a standard VLSI CMOS technology have recently been proposed as a compact pixel detector for the detection of high-energy charged particle in vertex/tracking applications. MAPS, also named CMOS sensors, are already extensively used in visible light applications. With respect to other competing imaging technologies, CMOS sensors have several potential advantages in terms of low cost, low power, lower noise at higher speed, random access of pixels which allows windowing of region of interest, ability to integrate several functions on the same chip. This brings altogether to the concept of 'camera-on-a-chip'. In this paper, we review the use of CMOS sensors for particle physics and we analyse their performances in term of the efficiency (fill factor), signal generation, noise, readout speed and sensor area. In most of high-energy physics applications, data reduction is needed in the sensor at an early stage of the data processing before transfer of the data to tape. Because of the large number of pixels, data reduction is needed on the sensor itself or just outside. This brings in stringent requirements on the temporal noise as well as to the sensor uniformity, expressed as a Fixed Pattern Noise (FPN). A pixel architecture with an additional transistor is proposed. This architecture, coupled to correlated double sampling of the signal will allow cancellation of the two dominant noise sources, namely the reset or kTC noise and the FPN. A prototype has been designed in a standard 0.25 μm CMOS technology. It has also a structure for electrical calibration of the sensor. The prototype is functional and detailed tests are under way.

  6. Dependent video coding using a tree representation of pixel dependencies

    NASA Astrophysics Data System (ADS)

    Amati, Luca; Valenzise, Giuseppe; Ortega, Antonio; Tubaro, Stefano

    2011-09-01

    Motion-compensated prediction induces a chain of coding dependencies between pixels in video. In principle, an optimal selection of encoding parameters (motion vectors, quantization parameters, coding modes) should take into account the whole temporal horizon of a GOP. However, in practical coding schemes, these choices are made on a frame-by-frame basis, thus with a possible loss of performance. In this paper we describe a tree-based model for pixelwise coding dependencies: each pixel in a frame is the child of a pixel in a previous reference frame. We show that some tree structures are more favorable than others from a rate-distortion perspective, e.g., because they entail a large descendance of pixels which are well predicted from a common ancestor. In those cases, a higher quality has to be assigned to pixels at the top of such trees. We promote the creation of these structures by adding a special discount term to the conventional Lagrangian cost adopted at the encoder. The proposed model can be implemented through a double-pass encoding procedure. Specifically, we devise heuristic cost functions to drive the selection of quantization parameters and of motion vectors, which can be readily implemented into a state-of-the-art H.264/AVC encoder. Our experiments demonstrate that coding efficiency is improved for video sequences with low motion, while there are no apparent gains for more complex motion. We argue that this is due to both the presence of complex encoder features not captured by the model, and to the complexity of the source to be encoded.

  7. SNR improvement for hyperspectral application using frame and pixel binning

    NASA Astrophysics Data System (ADS)

    Rehman, Sami Ur; Kumar, Ankush; Banerjee, Arup

    2016-05-01

    Hyperspectral imaging spectrometer systems are increasingly being used in the field of remote sensing for variety of civilian and military applications. The ability of such instruments in discriminating finer spectral features along with improved spatial and radiometric performance have made such instruments a powerful tool in the field of remote sensing. Design and development of spaceborne hyper spectral imaging spectrometers poses lot of technological challenges in terms of optics, dispersion element, detectors, electronics and mechanical systems. The main factors that define the type of detectors are the spectral region, SNR, dynamic range, pixel size, number of pixels, frame rate, operating temperature etc. Detectors with higher quantum efficiency and higher well depth are the preferred choice for such applications. CCD based Si detectors serves the requirement of high well depth for VNIR band spectrometers but suffers from smear. Smear can be controlled by using CMOS detectors. Si CMOS detectors with large format arrays are available. These detectors generally have smaller pitch and low well depth. Binning technique can be used with available CMOS detectors to meet the large swath, higher resolution and high SNR requirements. Availability of larger dwell time of satellite can be used to bin multiple frames to increase the signal collection even with lesser well depth detectors and ultimately increase the SNR. Lab measurements reveal that SNR improvement by frame binning is more in comparison to pixel binning. Effect of pixel binning as compared to the frame binning will be discussed and degradation of SNR as compared to theoretical value for pixel binning will be analyzed.

  8. Automation of Endmember Pixel Selection in SEBAL/METRIC Model

    NASA Astrophysics Data System (ADS)

    Bhattarai, N.; Quackenbush, L. J.; Im, J.; Shaw, S. B.

    2015-12-01

    The commonly applied surface energy balance for land (SEBAL) and its variant, mapping evapotranspiration (ET) at high resolution with internalized calibration (METRIC) models require manual selection of endmember (i.e. hot and cold) pixels to calibrate sensible heat flux. Current approaches for automating this process are based on statistical methods and do not appear to be robust under varying climate conditions and seasons. In this paper, we introduce a new approach based on simple machine learning tools and search algorithms that provides an automatic and time efficient way of identifying endmember pixels for use in these models. The fully automated models were applied on over 100 cloud-free Landsat images with each image covering several eddy covariance flux sites in Florida and Oklahoma. Observed land surface temperatures at automatically identified hot and cold pixels were within 0.5% of those from pixels manually identified by an experienced operator (coefficient of determination, R2, ≥ 0.92, Nash-Sutcliffe efficiency, NSE, ≥ 0.92, and root mean squared error, RMSE, ≤ 1.67 K). Daily ET estimates derived from the automated SEBAL and METRIC models were in good agreement with their manual counterparts (e.g., NSE ≥ 0.91 and RMSE ≤ 0.35 mm day-1). Automated and manual pixel selection resulted in similar estimates of observed ET across all sites. The proposed approach should reduce time demands for applying SEBAL/METRIC models and allow for their more widespread and frequent use. This automation can also reduce potential bias that could be introduced by an inexperienced operator and extend the domain of the models to new users.

  9. Hardware architecture of high-performance digital hologram generator on the basis of a pixel-by-pixel calculation scheme.

    PubMed

    Seo, Young-Ho; Lee, Yoon-Hyuk; Yoo, Ji-Sang; Kim, Dong-Wook

    2012-06-20

    In this paper we propose a hardware architecture for high-speed computer-generated hologram generation that significantly reduces the number of memory access times to avoid the bottleneck in the memory access operation. For this, we use three main schemes. The first is pixel-by-pixel calculation, rather than light source-by-source calculation. The second is a parallel calculation scheme extracted by modifying the previous recursive calculation scheme. The last scheme is a fully pipelined calculation scheme and exactly structured timing scheduling, achieved by adjusting the hardware. The proposed hardware is structured to calculate a row of a computer-generated hologram in parallel and each hologram pixel in a row is calculated independently. It consists of and input interface, an initial parameter calculator, hologram pixel calculators, a line buffer, and a memory controller. The implemented hardware to calculate a row of a 1920×1080 computer-generated hologram in parallel uses 168,960 lookup tables, 153,944 registers, and 19,212 digital signal processing blocks in an Altera field programmable gate array environment. It can stably operate at 198 MHz. Because of three schemes, external memory bandwidth is reduced to approximately 1/20,000 of the previous ones at the same calculation speed.

  10. A virtual pixel technology to enhance the resolution of monitors and for other purposes

    NASA Astrophysics Data System (ADS)

    Kading, Benjamin; Straub, Jeremy

    2015-05-01

    Current monitor and television displays utilize pixels to display an approximation of the real world collected by a camera or generated computationally. This paper proposes a virtual pixel technology which incorporates coloring LCD combination. Each physical pixel's configuration is based on a weighted average of the virtual pixels it contributes to. This allows lower pixel density displays to produce the approximation of a higher pixel density, while lowering production cost. The paper provides an overview of the proposed technology, discusses its application to monitors and extension to other areas and concludes with a discussion of the next steps to its development.

  11. A novel CMOS sensor with in-pixel auto-zeroed discrimination for charged particle tracking

    NASA Astrophysics Data System (ADS)

    Degerli, Y.; Guilloux, F.; Orsini, F.

    2014-05-01

    With the aim of developing fast and granular Monolithic Active Pixels Sensors (MAPS) as new charged particle tracking detectors for high energy physics experiments, a new rolling shutter binary pixel architecture concept (RSBPix) with in-pixel correlated double sampling, amplification and discrimination is presented. The discriminator features auto-zeroing in order to compensate process-related transistor mismatches. In order to validate the pixel, a first monolithic CMOS sensor prototype, including a pixel array of 96 × 64 pixels, has been designed and fabricated in the Tower-Jazz 0.18 μm CMOS Image Sensor (CIS) process. Results of laboratory tests are presented.

  12. High throughput optoelectronic smart pixel systems using diffractive optics

    NASA Astrophysics Data System (ADS)

    Chen, Chih-Hao

    1999-12-01

    Recent developments in digital video, multimedia technology and data networks have greatly increased the demand for high bandwidth communication channels and high throughput data processing. Electronics is particularly suited for switching, amplification and logic functions, while optics is more suitable for interconnections and communications with lower energy and crosstalk. In this research, we present the design, testing, integration and demonstration of several optoelectronic smart pixel devices and system architectures. These systems integrate electronic switching/processing capability with parallel optical interconnections to provide high throughput network communication and pipeline data processing. The Smart Pixel Array Cellular Logic processor (SPARCL) is designed in 0.8 m m CMOS and hybrid integrated with Multiple-Quantum-Well (MQW) devices for pipeline image processing. The Smart Pixel Network Interface (SAPIENT) is designed in 0.6 m m GaAs and monolithically integrated with LEDs to implement a highly parallel optical interconnection network. The Translucent Smart Pixel Array (TRANSPAR) design is implemented in two different versions. The first version, TRANSPAR-MQW, is designed in 0.5 m m CMOS and flip-chip integrated with MQW devices to provide 2-D pipeline processing and translucent networking using the Carrier- Sense-MultipleAccess/Collision-Detection (CSMA/CD) protocol. The other version, TRANSPAR-VM, is designed in 1.2 m m CMOS and discretely integrated with VCSEL-MSM (Vertical-Cavity-Surface- Emitting-Laser and Metal-Semiconductor-Metal detectors) chips and driver/receiver chips on a printed circuit board. The TRANSPAR-VM provides an option of using the token ring network protocol in addition to the embedded functions of TRANSPAR-MQW. These optoelectronic smart pixel systems also require micro-optics devices to provide high resolution, high quality optical interconnections and external source arrays. In this research, we describe an innovative

  13. A comparative study of Ir(III) complexes with pyrazino[2,3-f][1,10]phenanthroline and pyrazino[2,3-f][4,7]phenanthroline ligands in light-emitting electrochemical cells (LECs).

    PubMed

    González, Iván; Dreyse, Paulina; Cortés-Arriagada, Diego; Sundararajan, Mahesh; Morgado, Claudio; Brito, Iván; Roldán-Carmona, Cristina; Bolink, Henk J; Loeb, Bárbara

    2015-09-01

    We report the comparative study of the electrochemical and photoluminescent properties of two Ir(iii) complexes described as [Ir(F2ppy)2(N^N)][PF6], where the F2ppy ligand is 2-(2,4-difluorophenyl)pyridine and the N^N ligands are pyrazino[2,3-f][1,10]phenanthroline (ppl) and pyrazino[2,3-f][4,7]phenanthroline (ppz). The complexes were used for the fabrication of light-emitting electrochemical cells (LECs). The structures of the complexes have been corroborated by X-ray crystallography. Theoretical calculations were performed to understand the photophysical behavior of the complexes. Both in solution and solid state, the photoluminescence spectra shows that emission is significantly red-shifted in the [Ir(F2ppy)2(ppz)][PF6] complex compared with the [Ir(F2ppy)2(ppl)][PF6] complex. Besides, the [Ir(F2ppy)2(ppl)][PF6] complex exhibits a higher quantum yield and a longer excited state lifetime than the [Ir(F2ppy)2(ppz)][PF6] complex; therefore, in the last case non-radiative decay is predominant due to the stabilization of LUMO orbital (energy gap law). In the fabrication of LEC devices with the [Ir(F2ppy)2(ppl)][PF6] complex, light emission was obtained with a maximum value of luminance equal to 177 cd m(-2), while in the case of the [Ir(F2ppy)2(ppz)][PF6] complex, no luminance was observed. According to the photophysical data, the performance in LEC devices could be explained by the different position of the nitrogens in the ppl and ppz structural isomers, electronically affecting the complex, and therefore its properties. In addition, from the crystallographic analysis it is possible to note that the [Ir(F2ppy)2(ppz)][PF6] complex shows enhanced intermolecular and intramolecular interactions compared with [Ir(F2ppy)2(ppl)][PF6], and consequently a higher ordering of the molecules in the complex with ppz ligand can be expected. This higher order could favour the quenching processes, and consequently enhance the non-radiative deactivation. PMID:26219438

  14. Digital Pixel Sensor Array with Logarithmic Delta-Sigma Architecture

    PubMed Central

    Mahmoodi, Alireza; Li, Jing; Joseph, Dileepan

    2013-01-01

    Like the human eye, logarithmic image sensors achieve wide dynamic range easily at video rates, but, unlike the human eye, they suffer from low peak signal-to-noise-and-distortion ratios (PSNDRs). To improve the PSNDR, we propose integrating a delta-sigma analog-to-digital converter (ADC) in each pixel. An image sensor employing this architecture is designed, built and tested in 0.18 micron complementary metal-oxide-semiconductor (CMOS) technology. It achieves a PSNDR better than state-of-the-art logarithmic sensors and comparable to the human eye. As the approach concerns an array of many ADCs, we use a small-area low-power delta-sigma design. For scalability, each pixel has its own decimator. The prototype is compared to a variety of other image sensors, linear and nonlinear, from industry and academia. PMID:23959239

  15. Digital mammography: tradeoffs between 50- and 100-micron pixel size

    NASA Astrophysics Data System (ADS)

    Freedman, Matthew T.; Steller Artz, Dorothy E.; Jafroudi, Hamid; Lo, Shih-Chung B.; Zuurbier, Rebecca A.; Katial, Raj; Hayes, Wendelin S.; Wu, Chris Y.; Lin, Jyh-Shyan; Steinman, Richard M.; Tohme, Walid G.; Mun, Seong K.

    1995-05-01

    Improvements in mammography equipment related to a decrease in pixel size of digital mammography detectors raise questions of the possible effects of these new detectors. Mathematical modeling suggested that the benefits of moving from 100 to 50 micron detectors were slight and might not justify the cost of these new units. Experiments comparing screen film mammography, a storage phosphor 100 micron digital detector, a 50 micron digital breast spot device, 100 micron film digitization and 50 micron film digitization suggests that object conspicuity should be better for digital compared to conventional systems, but that there seemed to be minimal advantage to going from 100 to 50 microns. The 50 micron pixel system appears to provide a slight advantage in object contrast and perhaps in shape definition, but did not allow smaller objects to be detected.

  16. Measurement results of DIPIX pixel sensor developed in SOI technology

    NASA Astrophysics Data System (ADS)

    Ahmed, Mohammed Imran; Arai, Yasuo; Idzik, Marek; Kapusta, Piotr; Miyoshi, Toshinobu; Turala, Michal

    2013-08-01

    The development of integration type pixel detectors presents interest for physics communities because it brings optimization of design, simplicity of production-which means smaller cost, and reduction of detector material budget. During the last decade a lot of research and development activities took place in the field of CMOS Silicon-On-Insulator (SOI) technology resulting in improvement in wafer size, wafer resistivity and MIM capacitance. Several ideas have been tested successfully and are gradually entering into the application phase. Some of the novel concepts exploring SOI technology are pursued at KEK; several prototypes of dual mode integration type pixel (DIPIX) have been recently produced and described. This report presents initial test results of some of the prototypes including tests obtained with the infrared laser beams and Americium (Am-241) source. The Equivalent Noise Charge (ENC) of 86 e - has been measured. The measured performance demonstrates that SOI technology is a feasible choice for future applications.

  17. Development of prototype pixellated PIN CdZnTe detectors

    NASA Astrophysics Data System (ADS)

    Narita, Tomohiko; Bloser, Peter F.; Grindlay, Jonathan E.; Sudharsanan, R.; Reiche, C.; Stenstrom, Claudia

    1998-07-01

    We report initial results from the design and evaluation of two pixellated PIN Cadmium Zinc Telluride detectors and an ASIC-based readout system. The prototype imaging PIN detectors consist of 4 X 4 1.5 mm square indium anode contacts with 0.2 mm spacing and a solid cathode plane on 10 X 10 mm CdZnTe substrates of thickness 2 mm and 5 mm. The detector readout system, based on low noise preamplifier ASICs, allows for parallel readout of all channels upon cathode trigger. This prototype is under development for use in future astrophysical hard X-ray imagers with 10 - 600 keV energy response. Measurements of the detector uniformity, spatial resolution, and spectral resolution will be discussed and compared with a similar pixellated MSM detector. Finally, a prototype design for a large imaging array is outlined.

  18. Bonding techniques for hybrid active pixel sensors (HAPS)

    NASA Astrophysics Data System (ADS)

    Bigas, M.; Cabruja, E.; Lozano, M.

    2007-05-01

    A hybrid active pixel sensor (HAPS) consists of an array of sensing elements which is connected to an electronic read-out unit. The most used way to connect these two different devices is bump bonding. This interconnection technique is very suitable for these systems because it allows a very fine pitch and a high number of I/Os. However, there are other interconnection techniques available such as direct bonding. This paper, as a continuation of a review [M. Lozano, E. Cabruja, A. Collado, J. Santander, M. Ullan, Nucl. Instr. and Meth. A 473 (1-2) (2001) 95-101] published in 2001, presents an update of the different advanced bonding techniques available for manufacturing a hybrid active pixel detector.

  19. Using Trained Pixel Classifiers to Select Images of Interest

    NASA Technical Reports Server (NTRS)

    Mazzoni, D.; Wagstaff, K.; Castano, R.

    2004-01-01

    We present a machine-learning-based approach to ranking images based on learned priorities. Unlike previous methods for image evaluation, which typically assess the value of each image based on the presence of predetermined specific features, this method involves using two levels of machine-learning classifiers: one level is used to classify each pixel as belonging to one of a group of rather generic classes, and another level is used to rank the images based on these pixel classifications, given some example rankings from a scientist as a guide. Initial results indicate that the technique works well, producing new rankings that match the scientist's rankings significantly better than would be expected by chance. The method is demonstrated for a set of images collected by a Mars field-test rover.

  20. Current progress on pixel level packaging for uncooled IRFPA

    NASA Astrophysics Data System (ADS)

    Dumont, G.; Rabaud, W.; Yon, J.-J.; Carle, L.; Goudon, V.; Vialle, C.; Becker, Sébastien; Hamelin, Antoine; Arnaud, A.

    2012-06-01

    Vacuum packaging is definitely a major cost driver for uncooled IRFPA and a technological breakthrough is still expected to comply with the very low cost infrared camera market. To address this key issue, CEA-LETI is developing a Pixel Level Packaging (PLP) technology which basically consists in capping each pixel under vacuum in the direct continuation of the wafer level bolometer process. Previous CEA-LETI works have yet shown the feasibility of PLP based microbolometers that exhibit the required thermal insulation and vacuum achievement. CEA-LETI is still pushing the technology which has been now applied for the first time on a CMOS readout circuit. The paper will report on the recent progress obtained on PLP technology with particular emphasis on the optical efficiency of the PLP arrangement compared to the traditional microbolometer packaging. Results including optical performances, aging studies and compatibility with CMOS readout circuit are extensively presented.

  1. Compressive sensing spectroscopy with a single pixel camera.

    PubMed

    Starling, David J; Storer, Ian; Howland, Gregory A

    2016-07-01

    Spectrometry requires high spectral resolution and high photometric precision while also balancing cost and complexity. We address these requirements by employing a compressive-sensing camera capable of improving signal acquisition speed and sensitivity in limited signal scenarios. In particular, we implement a fast single pixel spectrophotometer with no moving parts and measure absorption and emission spectra comparable with commercial products. Our method utilizes Hadamard matrices to sample the spectra and then minimizes the total variation of the signal. The experimental setup includes standard optics and a grating, a low-cost digital micromirror device, and an intensity detector. The resulting spectrometer produces a 512 pixel spectrum with low mean-squared error and up to a 90% reduction in data acquisition time when compared with a standard spectrophotometer.

  2. New SOFRADIR 10μm pixel pitch infrared products

    NASA Astrophysics Data System (ADS)

    Lefoul, X.; Pere-Laperne, N.; Augey, T.; Rubaldo, L.; Aufranc, Sébastien; Decaens, G.; Ricard, N.; Mazaleyrat, E.; Billon-Lanfrey, D.; Gravrand, Olivier; Bisotto, Sylvette

    2014-10-01

    Recent advances in miniaturization of IR imaging technology have led to a growing market for mini thermal-imaging sensors. In that respect, Sofradir development on smaller pixel pitch has made much more compact products available to the users. When this competitive advantage is mixed with smaller coolers, made possible by HOT technology, we achieved valuable reductions in the size, weight and power of the overall package. At the same time, we are moving towards a global offer based on digital interfaces that provides our customers simplifications at the IR system design process while freeing up more space. This paper discusses recent developments on hot and small pixel pitch technologies as well as efforts made on compact packaging solution developed by SOFRADIR in collaboration with CEA-LETI.

  3. Characterization of indium and solder bump bonding for pixel detectors

    SciTech Connect

    Selcuk Cihangir and Simon Kwan

    2000-09-28

    A review of different bump-bonding processes used for pixel detectors is given. A large scale test on daisy-chained components from two vendors has been carried out at Fermilab to characterize the yield of these processes. The vendors are Advanced Interconnect Technology Ltd. (AIT) of Hong Kong and MCNC in North Carolina, US. The results from this test are presented and technical challenges encountered are discussed.

  4. Planar slim-edge pixel sensors for the ATLAS upgrades

    NASA Astrophysics Data System (ADS)

    Altenheiner, S.; Goessling, C.; Jentzsch, J.; Klingenberg, R.; Lapsien, T.; Muenstermann, D.; Rummler, A.; Troska, G.; Wittig, T.

    2012-02-01

    The ATLAS detector at CERN is a general-purpose experiment at the Large Hadron Collider (LHC). The ATLAS Pixel Detector is the innermost tracking detector of ATLAS and requires a sufficient level of hermeticity to achieve superb track reconstruction performance. The current planar n-type pixel sensors feature a pixel matrix of n+-implantations which is (on the opposite p-side) surrounded by so-called guard rings to reduce the high voltage stepwise towards the cutting edge and an additional safety margin. Because of the inactive region around the active area, the sensor modules have been shingled on top of each other's edge which limits the thermal performance and adds complexity in the present detector. The first upgrade phase of the ATLAS pixel detector will consist of the insertable b-layer (IBL), an additional b-layer which will be inserted into the present detector in 2013. Several changes in the sensor design with respect to the existing detector had to be applied to comply with the IBL's specifications and are described in detail. A key issue for the ATLAS upgrades is a flat arrangement of the sensors. To maintain the required level of hermeticity in the detector, the inactive sensor edges have to be reduced to minimize the dead space between the adjacent detector modules. Unirradiated and irradiated sensors with the IBL design have been operated in test beams to study the efficiency performance in the sensor edge region and it was found that the inactive edge width could be reduced from 1100 μm to less than 250 μm.

  5. Sub-pixel spatial resolution wavefront phase imaging

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip (Inventor); Mooney, James T. (Inventor)

    2012-01-01

    A phase imaging method for an optical wavefront acquires a plurality of phase images of the optical wavefront using a phase imager. Each phase image is unique and is shifted with respect to another of the phase images by a known/controlled amount that is less than the size of the phase imager's pixels. The phase images are then combined to generate a single high-spatial resolution phase image of the optical wavefront.

  6. Validity Assessment of Pixel Linear Spectral Mixing Through Laboratory Measurements

    NASA Astrophysics Data System (ADS)

    Mobasheri, M. R.; Dehnavi, S.; Maghsoudi, Y.

    2015-12-01

    In order to understand the characteristics of the data collected by hyperspectral imaging systems, it is important to discuss the physics behind the scene radiance field incident on the imaging system. A dominant effect in hyperspectral remote sensing is the mixing of radiant energies contributed from different materials present in a given pixel. The basic assumption of mixture modelling is that within a given scene, the surface is covered by a small number of distinct materials that have relatively constant spectral properties. It is most common to assume that the radiance reflected by different materials in a pixel can spectrally combine in a linear additive manner to produce the pixel radiance/reflectance, even when that might not be the case e.g. where the mixing process leads to nonlinear combinations of the radiance and where the linear assumption fails to hold. This can occur where there is significant relative three-dimensional structure within a given pixel. Without detailed knowledge of the dimensional structure, it can be very difficult to correctly ``un-mix'' the contributions of the various materials. This work aims to evaluate the correctness of the linear assumption in the mixture modelling using some laboratory measurements. Study was conducted using some sheets made of cellulose materials of different colours in 400-800 nm spectral range. Experimental results have shown that a correction term must be applied to the gains and offsets in the linear model. The obtained results can be extended to satellite sensors that acquire images in the above mentioned spectral range.

  7. A CMOS In-Pixel CTIA High Sensitivity Fluorescence Imager

    PubMed Central

    Murari, Kartikeya; Etienne-Cummings, Ralph; Thakor, Nitish; Cauwenberghs, Gert

    2012-01-01

    Traditionally, charge coupled device (CCD) based image sensors have held sway over the field of biomedical imaging. Complementary metal oxide semiconductor (CMOS) based imagers so far lack sensitivity leading to poor low-light imaging. Certain applications including our work on animal-mountable systems for imaging in awake and unrestrained rodents require the high sensitivity and image quality of CCDs and the low power consumption, flexibility and compactness of CMOS imagers. We present a 132×124 high sensitivity imager array with a 20.1 μm pixel pitch fabricated in a standard 0.5 μ CMOS process. The chip incorporates n-well/p-sub photodiodes, capacitive transimpedance amplifier (CTIA) based in-pixel amplification, pixel scanners and delta differencing circuits. The 5-transistor all-nMOS pixel interfaces with peripheral pMOS transistors for column-parallel CTIA. At 70 fps, the array has a minimum detectable signal of 4 nW/cm2 at a wavelength of 450 nm while consuming 718 μA from a 3.3 V supply. Peak signal to noise ratio (SNR) was 44 dB at an incident intensity of 1 μW/cm2. Implementing 4×4 binning allowed the frame rate to be increased to 675 fps. Alternately, sensitivity could be increased to detect about 0.8 nW/cm2 while maintaining 70 fps. The chip was used to image single cell fluorescence at 28 fps with an average SNR of 32 dB. For comparison, a cooled CCD camera imaged the same cell at 20 fps with an average SNR of 33.2 dB under the same illumination while consuming over a watt. PMID:23136624

  8. Analysis of the production of ATLAS indium bonded pixel modules

    NASA Astrophysics Data System (ADS)

    Alimonti, G.; Andreazza, A.; Bulgheroni, A.; Corda, G.; Di Gioia, S.; Fiorello, A.; Gemme, C.; Koziel, M.; Manca, F.; Meroni, C.; Nechaeva, P.; Paoloni, A.; Rossi, L.; Rovani, A.; Ruscino, E.

    2006-09-01

    The ATLAS collaboration is currently building 1500 pixel modules using the indium bump bonding technique developed by SELEX Sistemi Integrati (former AMS). The indium deposition and flip-chip process are described together with an overview of the chip stripping machine that allows defective modules to be reworked. The production is half-way through at the time of this writing. This paper also discusses the problems encountered during production and the adopted solutions.

  9. Active pixel imagers incorporating pixel-level amplifiers based on polycrystalline-silicon thin-film transistors.

    PubMed

    El-Mohri, Youcef; Antonuk, Larry E; Koniczek, Martin; Zhao, Qihua; Li, Yixin; Street, Robert A; Lu, Jeng-Ping

    2009-07-01

    Active matrix, flat-panel imagers (AMFPIs) employing a 2D matrix of a-Si addressing TFTs have become ubiquitous in many x-ray imaging applications due to their numerous advantages. However, under conditions of low exposures and/or high spatial resolution, their signal-to-noise performance is constrained by the modest system gain relative to the electronic additive noise. In this article, a strategy for overcoming this limitation through the incorporation of in-pixel amplification circuits, referred to as active pixel (AP) architectures, using polycrystalline-silicon (poly-Si) TFTs is reported. Compared to a-Si, poly-Si offers substantially higher mobilities, enabling higher TFT currents and the possibility of sophisticated AP designs based on both n- and p-channel TFTs. Three prototype indirect detection arrays employing poly-Si TFTs and a continuous a-Si photodiode structure were characterized. The prototypes consist of an array (PSI-1) that employs a pixel architecture with a single TFT, as well as two arrays (PSI-2 and PSI-3) that employ AP architectures based on three and five TFTs, respectively. While PSI-1 serves as a reference with a design similar to that of conventional AMFPI arrays, PSI-2 and PSI-3 incorporate additional in-pixel amplification circuitry. Compared to PSI-1, results of x-ray sensitivity demonstrate signal gains of approximately 10.7 and 20.9 for PSI-2 and PSI-3, respectively. These values are in reasonable agreement with design expectations, demonstrating that poly-Si AP circuits can be tailored to provide a desired level of signal gain. PSI-2 exhibits the same high levels of charge trapping as those observed for PSI-1 and other conventional arrays employing a continuous photodiode structure. For PSI-3, charge trapping was found to be significantly lower and largely independent of the bias voltage applied across the photodiode. MTF results indicate that the use of a continuous photodiode structure in PSI-1, PSI-2, and PSI-3 results in

  10. Active pixel imagers incorporating pixel-level amplifiers based on polycrystalline-silicon thin-film transistors

    SciTech Connect

    El-Mohri, Youcef; Antonuk, Larry E.; Koniczek, Martin; Zhao Qihua; Li Yixin; Street, Robert A.; Lu Jengping

    2009-07-15

    Active matrix, flat-panel imagers (AMFPIs) employing a 2D matrix of a-Si addressing TFTs have become ubiquitous in many x-ray imaging applications due to their numerous advantages. However, under conditions of low exposures and/or high spatial resolution, their signal-to-noise performance is constrained by the modest system gain relative to the electronic additive noise. In this article, a strategy for overcoming this limitation through the incorporation of in-pixel amplification circuits, referred to as active pixel (AP) architectures, using polycrystalline-silicon (poly-Si) TFTs is reported. Compared to a-Si, poly-Si offers substantially higher mobilities, enabling higher TFT currents and the possibility of sophisticated AP designs based on both n- and p-channel TFTs. Three prototype indirect detection arrays employing poly-Si TFTs and a continuous a-Si photodiode structure were characterized. The prototypes consist of an array (PSI-1) that employs a pixel architecture with a single TFT, as well as two arrays (PSI-2 and PSI-3) that employ AP architectures based on three and five TFTs, respectively. While PSI-1 serves as a reference with a design similar to that of conventional AMFPI arrays, PSI-2 and PSI-3 incorporate additional in-pixel amplification circuitry. Compared to PSI-1, results of x-ray sensitivity demonstrate signal gains of {approx}10.7 and 20.9 for PSI-2 and PSI-3, respectively. These values are in reasonable agreement with design expectations, demonstrating that poly-Si AP circuits can be tailored to provide a desired level of signal gain. PSI-2 exhibits the same high levels of charge trapping as those observed for PSI-1 and other conventional arrays employing a continuous photodiode structure. For PSI-3, charge trapping was found to be significantly lower and largely independent of the bias voltage applied across the photodiode. MTF results indicate that the use of a continuous photodiode structure in PSI-1, PSI-2, and PSI-3 results in optical

  11. Active pixel imagers incorporating pixel-level amplifiers based on polycrystalline-silicon thin-film transistors

    PubMed Central

    El-Mohri, Youcef; Antonuk, Larry E.; Koniczek, Martin; Zhao, Qihua; Li, Yixin; Street, Robert A.; Lu, Jeng-Ping

    2009-01-01

    Active matrix, flat-panel imagers (AMFPIs) employing a 2D matrix of a-Si addressing TFTs have become ubiquitous in many x-ray imaging applications due to their numerous advantages. However, under conditions of low exposures and∕or high spatial resolution, their signal-to-noise performance is constrained by the modest system gain relative to the electronic additive noise. In this article, a strategy for overcoming this limitation through the incorporation of in-pixel amplification circuits, referred to as active pixel (AP) architectures, using polycrystalline-silicon (poly-Si) TFTs is reported. Compared to a-Si, poly-Si offers substantially higher mobilities, enabling higher TFT currents and the possibility of sophisticated AP designs based on both n- and p-channel TFTs. Three prototype indirect detection arrays employing poly-Si TFTs and a continuous a-Si photodiode structure were characterized. The prototypes consist of an array (PSI-1) that employs a pixel architecture with a single TFT, as well as two arrays (PSI-2 and PSI-3) that employ AP architectures based on three and five TFTs, respectively. While PSI-1 serves as a reference with a design similar to that of conventional AMFPI arrays, PSI-2 and PSI-3 incorporate additional in-pixel amplification circuitry. Compared to PSI-1, results of x-ray sensitivity demonstrate signal gains of ∼10.7 and 20.9 for PSI-2 and PSI-3, respectively. These values are in reasonable agreement with design expectations, demonstrating that poly-Si AP circuits can be tailored to provide a desired level of signal gain. PSI-2 exhibits the same high levels of charge trapping as those observed for PSI-1 and other conventional arrays employing a continuous photodiode structure. For PSI-3, charge trapping was found to be significantly lower and largely independent of the bias voltage applied across the photodiode. MTF results indicate that the use of a continuous photodiode structure in PSI-1, PSI-2, and PSI-3 results in optical fill

  12. A Cherenkov camera with integrated electronics based on the ``Smart Pixel'' concept

    NASA Astrophysics Data System (ADS)

    Bulian, Norbert; Hirsch, Thomas; Hofmann, Werner; Kihm, Thomas; Kohnle, Antje; Panter, Michael; Stein, Michael

    2000-06-01

    An option for the cameras of the HESS telescopes, the concept of a modular camera based on ``Smart Pixels'' was developed. A Smart Pixel contains the photomultiplier, the high voltage supply for the photomultiplier, a dual-gain sample-and-hold circuit with a 14 bit dynamic range, a time-to-voltage converter, a trigger discriminator, trigger logic to detect a coincidence of X=1...7 neighboring pixels, and an analog ratemeter. The Smart Pixels plug into a common backplane which provides power, communicates trigger signals between neighboring pixels, and holds a digital control bus as well as an analog bus for multiplexed readout of pixel signals. The performance of the Smart Pixels has been studied using a 19-pixel test camera. .

  13. High-precision measurement of pixel positions in a charge-coupled device.

    PubMed

    Shaklan, S; Sharman, M C; Pravdo, S H

    1995-10-10

    The high level of spatial uniformity in modern CCD's makes them excellent devices for astrometric instruments. However, at the level of accuracy envisioned by the more ambitious projects such as the Astrometric Imaging Telescope, current technology produces CCD's with significant pixel registration errors. We describe a technique for making high-precision measurements of relative pixel positions. We measured CCD's manufactured for the Wide Field Planetary Camera II installed in the Hubble Space Telescope. These CCD's are shown to have significant step-and-repeat errors of 0.033 pixel along every 34th row, as well as a 0.003-pixel curvature along 34-pixel stripes. The source of these errors is described. Our experiments achieved a per-pixel accuracy of 0.011 pixel. The ultimate shot-noise limited precision of the method is less than 0.001 pixel.

  14. Pixelated spectral filter for integrated focal plane array in the long-wave IR

    NASA Astrophysics Data System (ADS)

    Kemme, S. A.; Boye, R. R.; Cruz-Cabrera, A. A.; Briggs, R. D.; Carter, T. R.; Samora, S.

    2010-04-01

    We present the design, fabrication, and characterization of a pixelated, hyperspectral arrayed component for Focal Plane Array (FPA) integration in the Long-Wave IR. This device contains tens of pixels within a single super-pixel which is tiled across the extent of the FPA. Each spectral pixel maps to a single FPA pixel with a spectral FWHM of 200nm. With this arrayed approach, remote sensing data may be accumulated with a non-scanning, "snapshot" imaging system. This technology is flexible with respect to individual pixel center wavelength and to pixel position within the array. Moreover, the entire pixel area has a single wavelength response, not the integrated linear response of a graded cavity thickness design. These requirements bar tilted, linear array technologies where the cavity length monotonically increases across the device.

  15. Small-Scale Readout Systems Prototype for the STAR PIXEL Detector

    SciTech Connect

    Szelezniak, Michal A.; Besson, Auguste; Colledani, Claude; Dorokhov, Andrei; Dulinski, Wojciech; Greiner, Leo C.; Himmi, Abdelkader; Hu, Christine; Matis, Howard S.; Ritter, Hans Georg; Rose, Andrew; Shabetai, Alexandre; Stezelberger, Thorsten; Sun, Xiangming; Thomas, Jim H.; Valin, Isabelle; Vu, Chinh Q.; Wieman, Howard H.; Winter, Marc

    2008-10-01

    A prototype readout system for the STAR PIXEL detector in the Heavy Flavor Tracker (HFT) vertex detector upgrade is presented. The PIXEL detector is a Monolithic Active Pixel Sensor (MAPS) based silicon pixel vertex detector fabricated in a commercial CMOS process that integrates the detector and front-end electronics layers in one silicon die. Two generations ofMAPS prototypes designed specifically for the PIXEL are discussed. We have constructed a prototype telescope system consisting of three small MAPS sensors arranged in three parallel and coaxial planes with a readout system based on the readout architecture for PIXEL. This proposed readout architecture is simple and scales to the size required to readout the final detector. The real-time hit finding algorithm necessary for data rate reduction in the 400 million pixel detector is described, and aspects of the PIXEL system integration into the existing STAR framework are addressed. The complete system has been recently tested and shown to be fully functional.

  16. Digital pixel readout integrated circuit architectures for LWIR

    NASA Astrophysics Data System (ADS)

    Shafique, Atia; Yazici, Melik; Kayahan, Huseyin; Ceylan, Omer; Gurbuz, Yasar

    2015-06-01

    This paper presents and discusses digital pixel readout integrated circuit architectures for long wavelength infrared (LWIR) in CMOS technology. Presented architectures are designed for scanning and staring arrays type detectors respectively. For scanning arrays, digital time delay integration (TDI) is implemented on 8 pixels with sampling rate up to 3 using CMOS 180nm technology. Input referred noise of ROIC is below 750 rms electron meanwhile power dissipation is appreciably under 30mW. ROIC design is optimized to perform at room as well as cryogenic temperatures. For staring type arrays, a digital pixel architecture relying on coarse quantization with pulse frequency modulation (PFM) and novel approach of extended integration is presented. It can achieve extreme charge handling capacity of 2.04Ge- with 20 bit output resolution and power dissipation below 350 nW in CMOS 90nm technology. Efficient mechanism of measuring the time to estimate the remaining charge on integration capacitor in order to achieve low SNR has employed.

  17. Development of thin edgeless silicon pixel sensors on epitaxial wafers

    NASA Astrophysics Data System (ADS)

    Boscardin, M.; Bosisio, L.; Contin, G.; Giacomini, G.; Manzari, V.; Orzan, G.; Rashevskaya, I.; Ronchin, S.; Zorzi, N.

    2014-09-01

    The paper reports on the development of novel p-on-n thin edgeless planar pixel sensors, compatible with ALICE front-end electronics, fabricated by FBK on epitaxial material. The focus of the activity is the minimization of the material budget required for hybrid pixel detectors. This goal has been addressed in two different stages. In the first one, planar pixel detectors fabricated on epitaxial wafers have been thinned and bonded to the readout chips. The second stage is described by the present paper: the `active edge' concept has been studied for the reduction of the dead area at the periphery of the devices. An overview of the key technological steps and of the electrical characterization of the fabricated sensors is given. In addition, the preliminary results on the static behavior of test sensors after neutron irradiation at different fluences (up to 2.5 × 1015 1 MeV-neq/cm2) are reported. The results demonstrate that these kinds of devices are a viable solution for the reduction of the material budget while maintaining the typical electrical characteristics expected from radiation silicon sensors.

  18. Demosaiced pixel super-resolution for multiplexed holographic color imaging.

    PubMed

    Wu, Yichen; Zhang, Yibo; Luo, Wei; Ozcan, Aydogan

    2016-01-01

    To synthesize a holographic color image, one can sequentially take three holograms at different wavelengths, e.g., at red (R), green (G) and blue (B) parts of the spectrum, and digitally merge them. To speed up the imaging process by a factor of three, a Bayer color sensor-chip can also be used to demultiplex three wavelengths that simultaneously illuminate the sample and digitally retrieve individual set of holograms using the known transmission spectra of the Bayer color filters. However, because the pixels of different channels (R, G, B) on a Bayer color sensor are not at the same physical location, conventional demosaicing techniques generate color artifacts in holographic imaging using simultaneous multi-wavelength illumination. Here we demonstrate that pixel super-resolution can be merged into the color de-multiplexing process to significantly suppress the artifacts in wavelength-multiplexed holographic color imaging. This new approach, termed Demosaiced Pixel Super-Resolution (D-PSR), generates color images that are similar in performance to sequential illumination at three wavelengths, and therefore improves the speed of holographic color imaging by 3-fold. D-PSR method is broadly applicable to holographic microscopy applications, where high-resolution imaging and multi-wavelength illumination are desired. PMID:27353242

  19. Sub pixel location identification using super resolved multilooking CHRIS data

    NASA Astrophysics Data System (ADS)

    Sahithi, V. S.; Agrawal, S.

    2014-11-01

    CHRIS /Proba is a multiviewing hyperspectral sensor that monitors the earth in five different zenith angles +55°, +36°, nadir, -36° and -55° with a spatial resolution of 17 m and within a spectral range of 400-1050 nm in mode 3. These multiviewing images are suitable for constructing a super resolved high resolution image that can reveal the mixed pixel of the hyperspectral image. In the present work, an attempt is made to find the location of various features constituted within the 17m mixed pixel of the CHRIS image using various super resolution reconstruction techniques. Four different super resolution reconstruction techniques namely interpolation, iterative back projection, projection on to convex sets (POCS) and robust super resolution were tried on the -36, nadir and +36 images to construct a super resolved high resolution 5.6 m image. The results of super resolution reconstruction were compared with the scaled nadir image and bicubic convoluted image for comparision of the spatial and spectral property preservance. A support vector machine classification of the best super resolved high resolution image was performed to analyse the location of the sub pixel features. Validation of the obtained results was performed using the spectral unmixing fraction images and the 5.6 m classified LISS IV image.

  20. Demosaiced pixel super-resolution for multiplexed holographic color imaging

    PubMed Central

    Wu, Yichen; Zhang, Yibo; Luo, Wei; Ozcan, Aydogan

    2016-01-01

    To synthesize a holographic color image, one can sequentially take three holograms at different wavelengths, e.g., at red (R), green (G) and blue (B) parts of the spectrum, and digitally merge them. To speed up the imaging process by a factor of three, a Bayer color sensor-chip can also be used to demultiplex three wavelengths that simultaneously illuminate the sample and digitally retrieve individual set of holograms using the known transmission spectra of the Bayer color filters. However, because the pixels of different channels (R, G, B) on a Bayer color sensor are not at the same physical location, conventional demosaicing techniques generate color artifacts in holographic imaging using simultaneous multi-wavelength illumination. Here we demonstrate that pixel super-resolution can be merged into the color de-multiplexing process to significantly suppress the artifacts in wavelength-multiplexed holographic color imaging. This new approach, termed Demosaiced Pixel Super-Resolution (D-PSR), generates color images that are similar in performance to sequential illumination at three wavelengths, and therefore improves the speed of holographic color imaging by 3-fold. D-PSR method is broadly applicable to holographic microscopy applications, where high-resolution imaging and multi-wavelength illumination are desired. PMID:27353242

  1. Demosaiced pixel super-resolution for multiplexed holographic color imaging

    NASA Astrophysics Data System (ADS)

    Wu, Yichen; Zhang, Yibo; Luo, Wei; Ozcan, Aydogan

    2016-06-01

    To synthesize a holographic color image, one can sequentially take three holograms at different wavelengths, e.g., at red (R), green (G) and blue (B) parts of the spectrum, and digitally merge them. To speed up the imaging process by a factor of three, a Bayer color sensor-chip can also be used to demultiplex three wavelengths that simultaneously illuminate the sample and digitally retrieve individual set of holograms using the known transmission spectra of the Bayer color filters. However, because the pixels of different channels (R, G, B) on a Bayer color sensor are not at the same physical location, conventional demosaicing techniques generate color artifacts in holographic imaging using simultaneous multi-wavelength illumination. Here we demonstrate that pixel super-resolution can be merged into the color de-multiplexing process to significantly suppress the artifacts in wavelength-multiplexed holographic color imaging. This new approach, termed Demosaiced Pixel Super-Resolution (D-PSR), generates color images that are similar in performance to sequential illumination at three wavelengths, and therefore improves the speed of holographic color imaging by 3-fold. D-PSR method is broadly applicable to holographic microscopy applications, where high-resolution imaging and multi-wavelength illumination are desired.

  2. Pixel diamond detectors for excimer laser beam diagnostics

    NASA Astrophysics Data System (ADS)

    Girolami, M.; Allegrini, P.; Conte, G.; Salvatori, S.

    2011-05-01

    Laser beam profiling technology in the UV spectrum of light is evolving with the increase of excimer lasers and lamps applications, that span from lithography for VLSI circuits to eye surgery. The development of a beam-profiler, able to capture the excimer laser single pulse and process the acquired pixel current signals in the time period between each pulse, is mandatory for such applications. 1D and 2D array detectors have been realized on polycrystalline CVD diamond specimens. The fast diamond photoresponse, in the ns time regime, suggests the suitability of such devices for fine tuning feedback of high-power pulsed-laser cavities, whereas solar-blindness guarantees high performance in UV beam diagnostics, also under high intensity background illumination. Offering unique properties in terms of thermal conductivity and visible-light transparency, diamond represents one of the most suitable candidate for the detection of high-power UV laser emission. The relatively high resistivity of diamond in the dark has allowed the fabrication of photoconductive vertical pixel-detectors. A semitransparent light-receiving back-side contact has been used for detector biasing. Each pixel signal has been conditioned by a multi-channel read-out electronics made up of a high-sensitive integrator and a Σ-Δ A/D converter. The 500 μs conversion time has allowed a data acquisition rate up to 2 kSPS (Sample Per Second).

  3. Simulation of charge transport in pixelated CdTe

    NASA Astrophysics Data System (ADS)

    Kolstein, M.; Ariño, G.; Chmeissani, M.; De Lorenzo, G.

    2014-12-01

    The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated semiconductor technology for nuclear medicine applications to achieve an improved image reconstruction without efficiency loss. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 106). The design is based on the use of a pixelated CdTe Schottky detector to have optimal energy and spatial resolution. An individual read-out channel is dedicated for each detector voxel of size 1 × 1 × 2 mm3 using an application-specific integrated circuit (ASIC) which the VIP project has designed, developed and is currently evaluating experimentally. The behaviour of the signal charge carriers in CdTe should be well understood because it has an impact on the performance of the readout channels. For this purpose the Finite Element Method (FEM) Multiphysics COMSOL software package has been used to simulate the behaviour of signal charge carriers in CdTe and extract values for the expected charge sharing depending on the impact point and bias voltage. The results on charge sharing obtained with COMSOL are combined with GAMOS, a Geant based particle tracking Monte Carlo software package, to get a full evaluation of the amount of charge sharing in pixelated CdTe for different gamma impact points.

  4. Demosaiced pixel super-resolution for multiplexed holographic color imaging.

    PubMed

    Wu, Yichen; Zhang, Yibo; Luo, Wei; Ozcan, Aydogan

    2016-06-29

    To synthesize a holographic color image, one can sequentially take three holograms at different wavelengths, e.g., at red (R), green (G) and blue (B) parts of the spectrum, and digitally merge them. To speed up the imaging process by a factor of three, a Bayer color sensor-chip can also be used to demultiplex three wavelengths that simultaneously illuminate the sample and digitally retrieve individual set of holograms using the known transmission spectra of the Bayer color filters. However, because the pixels of different channels (R, G, B) on a Bayer color sensor are not at the same physical location, conventional demosaicing techniques generate color artifacts in holographic imaging using simultaneous multi-wavelength illumination. Here we demonstrate that pixel super-resolution can be merged into the color de-multiplexing process to significantly suppress the artifacts in wavelength-multiplexed holographic color imaging. This new approach, termed Demosaiced Pixel Super-Resolution (D-PSR), generates color images that are similar in performance to sequential illumination at three wavelengths, and therefore improves the speed of holographic color imaging by 3-fold. D-PSR method is broadly applicable to holographic microscopy applications, where high-resolution imaging and multi-wavelength illumination are desired.

  5. Hexagonal Pixels and Indexing Scheme for Binary Images

    NASA Technical Reports Server (NTRS)

    Johnson, Gordon G.

    2004-01-01

    A scheme for resampling binaryimage data from a rectangular grid to a regular hexagonal grid and an associated tree-structured pixel-indexing scheme keyed to the level of resolution have been devised. This scheme could be utilized in conjunction with appropriate image-data-processing algorithms to enable automated retrieval and/or recognition of images. For some purposes, this scheme is superior to a prior scheme that relies on rectangular pixels: one example of such a purpose is recognition of fingerprints, which can be approximated more closely by use of line segments along hexagonal axes than by line segments along rectangular axes. This scheme could also be combined with algorithms for query-image-based retrieval of images via the Internet. A binary image on a rectangular grid is generated by raster scanning or by sampling on a stationary grid of rectangular pixels. In either case, each pixel (each cell in the rectangular grid) is denoted as either bright or dark, depending on whether the light level in the pixel is above or below a prescribed threshold. The binary data on such an image are stored in a matrix form that lends itself readily to searches of line segments aligned with either or both of the perpendicular coordinate axes. The first step in resampling onto a regular hexagonal grid is to make the resolution of the hexagonal grid fine enough to capture all the binaryimage detail from the rectangular grid. In practice, this amounts to choosing a hexagonal-cell width equal to or less than a third of the rectangular- cell width. Once the data have been resampled onto the hexagonal grid, the image can readily be checked for line segments aligned with the hexagonal coordinate axes, which typically lie at angles of 30deg, 90deg, and 150deg with respect to say, the horizontal rectangular coordinate axis. Optionally, one can then rotate the rectangular image by 90deg, then again sample onto the hexagonal grid and check for line segments at angles of 0deg, 60deg

  6. Modeling of Pixelated Detector in SPECT Pinhole Reconstruction

    PubMed Central

    Feng, Bing; Zeng, Gengsheng L.

    2014-01-01

    A challenge for the pixelated detector is that the detector response of a gamma-ray photon varies with the incident angle and the incident location within a crystal. The normalization map obtained by measuring the flood of a point-source at a large distance can lead to artifacts in reconstructed images. In this work, we investigated a method of generating normalization maps by ray-tracing through the pixelated detector based on the imaging geometry and the photo-peak energy for the specific isotope. The normalization is defined for each pinhole as the normalized detector response for a point-source placed at the focal point of the pinhole. Ray-tracing is used to generate the ideal flood image for a point-source. Each crystal pitch area on the back of the detector is divided into 60 × 60 sub-pixels. Lines are obtained by connecting between a point-source and the centers of sub-pixels inside each crystal pitch area. For each line ray-tracing starts from the entrance point at the detector face and ends at the center of a sub-pixel on the back of the detector. Only the attenuation by NaI(Tl) crystals along each ray is assumed to contribute directly to the flood image. The attenuation by the silica (SiO2) reflector is also included in the ray-tracing. To calculate the normalization for a pinhole, we need to calculate the ideal flood for a point-source at 360 mm distance (where the point-source was placed for the regular flood measurement) and the ideal flood image for the point-source at the pinhole focal point, together with the flood measurement at 360 mm distance. The normalizations are incorporated in the iterative OSEM reconstruction as a component of the projection matrix. Applications to single-pinhole and multi-pinhole imaging showed that this method greatly reduced the reconstruction artifacts. PMID:25574058

  7. Method of fabrication of display pixels driven by silicon thin film transistors

    DOEpatents

    Carey, Paul G.; Smith, Patrick M.

    1999-01-01

    Display pixels driven by silicon thin film transistors are fabricated on plastic substrates for use in active matrix displays, such as flat panel displays. The process for forming the pixels involves a prior method for forming individual silicon thin film transistors on low-temperature plastic substrates. Low-temperature substrates are generally considered as being incapable of withstanding sustained processing temperatures greater than about 200.degree. C. The pixel formation process results in a complete pixel and active matrix pixel array. A pixel (or picture element) in an active matrix display consists of a silicon thin film transistor (TFT) and a large electrode, which may control a liquid crystal light valve, an emissive material (such as a light emitting diode or LED), or some other light emitting or attenuating material. The pixels can be connected in arrays wherein rows of pixels contain common gate electrodes and columns of pixels contain common drain electrodes. The source electrode of each pixel TFT is connected to its pixel electrode, and is electrically isolated from every other circuit element in the pixel array.

  8. Building Detector Modules for the (S)CMS Pixel Barrel Detector

    NASA Astrophysics Data System (ADS)

    König, S.; PSI Pixel Group

    2009-12-01

    For the barrel part of the CMS pixel tracker about 800 silicon pixel detector modules are required. The modules are bump bonded, assembled and tested at the Paul Scherrer Institute. This article gives the production results of the module assembly for the CMS experiment and shows the evolution of the barrel pixel module design for the first phase of the LHC luminosity upgrade.

  9. Performance of Pixel-Readout Micro-Pixel Chamber with Analog-Readout System Used as X-ray Polarimeter

    NASA Astrophysics Data System (ADS)

    Katagiri, Hideaki; Ono, Kenichi; Uchiyama, Hideki; Tsuru, Takeshi Go; Matsumoto, Hironori; Hyodo, Yoshiaki; Kubo, Hidetoshi; Miuchi, Kentaro; Tanimori, Toru

    2007-12-01

    We developed an analog-readout system for a pixel-readout micro-pixel chamber (μ-PIC) to be used as an astronomical X-ray polarimeter, and demonstrated that the sensitivity of the new system reached up to that predicted by a simulation. A pixel-readout μ-PIC is a micro-pattern gaseous detector with a fine position resolution and good stability at sufficient gain operation, and is suited for astronomical X-ray polarimetry. However, as shown by Katagiri et al. (2007), the sensitivity to X-ray polarization was found to be statistically lower by a significant amount than that expected from the simulation of Ueno et al. [Nucl. Instrum. Methods Phys. Res., Sect. A 525 (2004) 28] because of the readout system and background produced by the scattering of the X-ray beam in air. We therefore developed a new readout system and carried out a beam test with aluminum tubes that reduced the background. As a result, we demonstrated that for collimated beams, the modulation factors, which are indicators of the sensitivity to X-ray polarization, were 0.24± 0.08 at 8 keV and 0.18± 0.07 at 15 keV in a neon-based gas mixture, and 0.18± 0.04 at 15 keV in an argon-based mixture. These values are consistent with those predicted by the simulation within errors.

  10. Droplet Combustion Experiment movie

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The Droplet Combustion Experiment (DCE) was designed to investigate the fundamental combustion aspects of single, isolated droplets under different pressures and ambient oxygen concentrations for a range of droplet sizes varying between 2 and 5 mm. The DCE principal investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1 mission (STS-83, April 4-8 1997; the shortened mission was reflown as MSL-1R on STS-94). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (1.1 MB, 12-second MPEG, screen 320 x 240 pixels; downlinked video, higher quality not available)A still JPG composite of this movie is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300164.html.

  11. Sub-pixel calibration for Weak Lensing and Astrometry

    NASA Astrophysics Data System (ADS)

    Shao, Michael

    We have recently developed and demonstrated a new method of sub-pixel detector calibration that offers orders of magnitude improvement in astrometry with CCD focal planes. Using this technique we have demonstrated centroiding of images to 1e 5 lambda/D in laboratory conditions. Our method allows reconstructing the true optical point spread function (PSF) of a telescope from pixelated stellar images. Although this technique was originally developed for centroiding of images across a large focal plane, it can also be applied to weak lensing program on WFIRST. We use a laser metrology technique to measure geometric imperfections in the focal plane array from pixel placement errors to non-uniform quantum efficiency (QE) within every pixel. With precise sub-pixel calibration one can use dithered images (e.g., a 2×2 dither) to derive Nyquist-sampled image of stars. The WFIRST telescope has a large 0.28 sq.deg field of view (FOV) with theoretical PSF varying considerably over that FOV. However, even at high galactic latitude there will be over 1,000 stars brighter than 16 mag and, with Nyquist-sampled images, it should be possible to calculate the spatially varying PSF at 1,000 locations in the focal plane. With knowledge of the optical PSF and sub-pixel calibration of the detector, one can remove biases in the shapes of galaxies introduced by the spatially varying PSF. The technique of sub-pixel calibration has so far only been demonstrated in with visible CCD detectors and applied to achieve ultra-precise image centroiding. The purpose of this proposal is to extend the technique of removing biases in the shape of galaxies due to pixilation and spatially varying PSF and to extend the calibration of visible detectors to NIR detectors. The new technique could be used to enable 4 10 microarcsecond (μas) astrometry within the 0.28 sq.deg FOV of the WFIRST telescope. Using the upcoming Gaia catalogue accurate to ~10 μas, we will be able to stitch the HgCdTe arrays on

  12. Pixel-wise absolute phase unwrapping using geometric constraints of structured light system.

    PubMed

    An, Yatong; Hyun, Jae-Sang; Zhang, Song

    2016-08-01

    This paper presents a method to unwrap phase pixel by pixel by solely using geometric constraints of the structured light system without requiring additional image acquisition or another camera. Specifically, an artificial absolute phase map, Φmin, at a given virtual depth plane z = zmin, is created from geometric constraints of the calibrated structured light system; the wrapped phase is pixel-by-pixel unwrapped by referring to Φmin. Since Φmin is defined in the projector space, the unwrapped phase obtained from this method is absolute for each pixel. Experimental results demonstrate the success of this proposed novel absolute phase unwrapping method. PMID:27505808

  13. CMOS Hybrid Pixel Detectors for Scientific, Industrial and Medical Applications

    NASA Astrophysics Data System (ADS)

    Broennimann, Christian

    2009-03-01

    Crystallography is the principal technique for determining macromolecular structures at atomic resolution and uses advantageously the high intensity of 3rd generation synchrotron X-ray sources . Macromolecular crystallography experiments benefit from excellent beamline equipment, recent software advances and modern X-ray detectors. However, the latter do not take full advantage of the brightness of modern synchrotron sources. CMOS Hybrid pixel array detectors, originally developed for high energy physics experiments, meet these requirements. X-rays are recorded in single photon counting mode and data thus are stored digitally at the earliest possible stage. This architecture leads to several advantages over current detectors: No detector noise is added to the signal. Readout time is reduced to a few milliseconds. The counting rates are matched to beam intensities at protein crystallography beamlines at 3rd generation synchrotrons. The detector is not sensitive to X-rays during readout; therefore no mechanical shutter is required. The detector has a very sharp point spread function (PSF) of one pixel, which allows better resolution of adjacent reflections. Low energy X-rays can be suppressed by the comparator At the Paul Scherrer Institute (PSI) in Switzerland the first and largest array based on this technology was constructed: The Pilatus 6M detector. The detector covers an area of 43.1 x 44.8 cm2 , has 6 million pixels and is read out noise free in 3.7 ms. Since June 2007 the detector is in routine operation at the beamline 6S of the Swiss Light Source (SLS). The company DETCRIS Ltd, has licensed the technology from PSI and is commercially offering the PILATUS detectors. Examples of the wide application range of the detectors will be shown.

  14. Optical differentiation wavefront sensor based on binary pixelated transmission filters

    NASA Astrophysics Data System (ADS)

    Qiao, J.; Travinsky, A.; Ding, G.; Dorrer, C.

    2015-03-01

    High-resolution wavefront sensors are used in a wide range of applications. The Shack-Hartmann sensor is the industry standard and mostly used for this kind of analysis. However, with this sensor the analysis can only be performed for narrowband radiation, the recoverable curvature of the wavefront slopes is also restricted by the size of a single lens in the microlens array. The high-resolution Shack Hartmann wavefront sensor (>128×128) is also significantly expensive. The optical differentiation wavefront sensor, on the other hand, consists of only simple and therefore inexpensive components, offers greater signal to noise ratio, allows for high-resolution analysis of wavefront curvature, and is potentially capable of performing broadband measurements. When a transmission mask with linear attenuation along a spatial direction modulates the far field of an optical wave, the spatial wavefront slope along that direction can be recovered from the fluence in the near field after modulation. With two orthogonal measurements one can recover the complete wavefront of the optical wave. In this study the characteristics of such a wavefront sensor are investigated when the linear transmission modulation is implemented with a pixelated binary filter. Such a filter can be produced as a gray-scale quasi-continuous transmission pattern constructed using arrays of small (e.g., 10-micron) transparent or opaque pixels and therefore it can simply be fabricated by conventional lithography techniques. Simulations demonstrate the potential ability of such a pixelated filter to match the performance of a filter with continuously varying transmission, while offering the advantage of better transmission control and reduction of fabrication costs.

  15. Single-pixel camera with one graphene photodetector.

    PubMed

    Li, Gongxin; Wang, Wenxue; Wang, Yuechao; Yang, Wenguang; Liu, Lianqing

    2016-01-11

    Consumer cameras in the megapixel range are ubiquitous, but the improvement of them is hindered by the poor performance and high cost of traditional photodetectors. Graphene, a two-dimensional micro-/nano-material, recently has exhibited exceptional properties as a sensing element in a photodetector over traditional materials. However, it is difficult to fabricate a large-scale array of graphene photodetectors to replace the traditional photodetector array. To take full advantage of the unique characteristics of the graphene photodetector, in this study we integrated a graphene photodetector in a single-pixel camera based on compressive sensing. To begin with, we introduced a method called laser scribing for fabrication the graphene. It produces the graphene components in arbitrary patterns more quickly without photoresist contamination as do traditional methods. Next, we proposed a system for calibrating the optoelectrical properties of micro/nano photodetectors based on a digital micromirror device (DMD), which changes the light intensity by controlling the number of individual micromirrors positioned at + 12°. The calibration sensitivity is driven by the sum of all micromirrors of the DMD and can be as high as 10(-5)A/W. Finally, the single-pixel camera integrated with one graphene photodetector was used to recover a static image to demonstrate the feasibility of the single-pixel imaging system with the graphene photodetector. A high-resolution image can be recovered with the camera at a sampling rate much less than Nyquist rate. The study was the first demonstration for ever record of a macroscopic camera with a graphene photodetector. The camera has the potential for high-speed and high-resolution imaging at much less cost than traditional megapixel cameras.

  16. Study of silicon pixel sensor for synchrotron radiation detection

    NASA Astrophysics Data System (ADS)

    Li, Zhen-Jie; Jia, Yun-Cong; Hu, Ling-Fei; Liu, Peng; Yin, Hua-Xiang

    2016-03-01

    The silicon pixel sensor (SPS) is one of the key components of hybrid pixel single-photon-counting detectors for synchrotron radiation X-ray detection (SRD). In this paper, the design, fabrication, and characterization of SPSs for single beam X-ray photon detection is reported. The designed pixel sensor is a p+-in-n structure with guard-ring structures operated in full-depletion mode and is fabricated on 4-inch, N type, 320 μm thick, high-resistivity silicon wafers by a general Si planar process. To achieve high energy resolution of X-rays and obtain low dark current and high breakdown voltage as well as appropriate depletion voltage of the SPS, a series of technical optimizations of device structure and fabrication process are explored. With optimized device structure and fabrication process, excellent SPS characteristics with dark current of 2 nA/cm2, full depletion voltage < 50 V and breakdown voltage >150 V are achieved. The fabricated SPSs are wire bonded to ASIC circuits and tested for the performance of X-ray response to the 1W2B synchrotron beam line of the Beijing Synchrotron Radiation Facility. The measured S-curves for SRD demonstrate a high discrimination for different energy X-rays. The extracted energy resolution is high (<20% for X-ray photon energy >10 keV) and the linear properties between input photo energy and the equivalent generator amplitude are well established. It confirmed that the fabricated SPSs have a good energy linearity and high count rate with the optimized technologies. The technology is expected to have a promising application in the development of a large scale SRD system for the Beijing Advanced Photon Source. Supported by Prefabrication Research of Beijing Advanced Photon Source (R&D for BAPS) and National Natural Science Foundation of China (11335010)

  17. Charge amplitude distribution of the Gossip gaseous pixel detector

    NASA Astrophysics Data System (ADS)

    Blanco Carballo, V. M.; Chefdeville, M.; Colas, P.; Giomataris, Y.; van der Graaf, H.; Gromov, V.; Hartjes, F.; Kluit, R.; Koffeman, E.; Salm, C.; Schmitz, J.; Smits, S. M.; Timmermans, J.; Visschers, J. L.

    2007-12-01

    The Gossip gaseous pixel detector is being developed for the detection of charged particles in extreme high radiation environments as foreseen close to the interaction point of the proposed super LHC. The detecting medium is a thin layer of gas. Because of the low density of this medium, only a few primary electron/ion pairs are created by the traversing particle. To get a detectable signal, the electrons drift towards a perforated metal foil (Micromegas) whereafter they are multiplied in a gas avalanche to provide a detectable signal. The gas avalanche occurs in the high field between the Micromegas and the pixel readout chip (ROC). Compared to a silicon pixel detector, Gossip features a low material budget and a low cooling power. An experiment using X-rays has indicated a possible high radiation tolerance exceeding 10 16 hadrons/cm 2. The amplified charge signal has a broad amplitude distribution due to the limited statistics of the primary ionization and the statistical variation of the gas amplification. Therefore, some degree of inefficiency is inevitable. This study presents experimental results on the charge amplitude distribution for CO 2/DME (dimethyl-ether) and Ar/iC 4H 10 mixtures. The measured curves were fitted with the outcome of a theoretical model. In the model, the physical Landau distribution is approximated by a Poisson distribution that is convoluted with the variation of the gas gain and the electronic noise. The value for the fraction of pedestal events is used for a direct calculation of the cluster density. For some gases, the measured cluster density is considerably lower than given in literature.

  18. A New Pixels Flipping Method for Huge Watermarking Capacity of the Invoice Font Image

    PubMed Central

    Li, Li; Hou, Qingzheng; Lu, Jianfeng; Dai, Junping; Mao, Xiaoyang; Chang, Chin-Chen

    2014-01-01

    Invoice printing just has two-color printing, so invoice font image can be seen as binary image. To embed watermarks into invoice image, the pixels need to be flipped. The more huge the watermark is, the more the pixels need to be flipped. We proposed a new pixels flipping method in invoice image for huge watermarking capacity. The pixels flipping method includes one novel interpolation method for binary image, one flippable pixels evaluation mechanism, and one denoising method based on gravity center and chaos degree. The proposed interpolation method ensures that the invoice image keeps features well after scaling. The flippable pixels evaluation mechanism ensures that the pixels keep better connectivity and smoothness and the pattern has highest structural similarity after flipping. The proposed denoising method makes invoice font image smoother and fiter for human vision. Experiments show that the proposed flipping method not only keeps the invoice font structure well but also improves watermarking capacity. PMID:25489606

  19. Large area CMOS bio-pixel array for compact high sensitive multiplex biosensing.

    PubMed

    Sandeau, Laure; Vuillaume, Cassandre; Contié, Sylvain; Grinenval, Eva; Belloni, Federico; Rigneault, Hervé; Owens, Roisin M; Fournet, Margaret Brennan

    2015-02-01

    A novel CMOS bio-pixel array which integrates assay substrate and assay readout is demonstrated for multiplex and multireplicate detection of a triplicate of cytokines with single digit pg ml(-1) sensitivities. Uniquely designed large area bio-pixels enable individual assays to be dedicated to and addressed by single pixels. A capability to simultaneously measure a large number of targets is provided by the 128 available pixels. Chemiluminescent assays are carried out directly on the pixel surface which also detects the emitted chemiluminescent photons, facilitating a highly compact sensor and reader format. The high sensitivity of the bio-pixel array is enabled by the high refractive index of silicon based pixels. This in turn generates a strong supercritical angle luminescence response significantly increasing the efficiency of the photon collection over conventional farfield modalities. PMID:25490928

  20. A new pixels flipping method for huge watermarking capacity of the invoice font image.

    PubMed

    Li, Li; Hou, Qingzheng; Lu, Jianfeng; Xu, Qishuai; Dai, Junping; Mao, Xiaoyang; Chang, Chin-Chen

    2014-01-01

    Invoice printing just has two-color printing, so invoice font image can be seen as binary image. To embed watermarks into invoice image, the pixels need to be flipped. The more huge the watermark is, the more the pixels need to be flipped. We proposed a new pixels flipping method in invoice image for huge watermarking capacity. The pixels flipping method includes one novel interpolation method for binary image, one flippable pixels evaluation mechanism, and one denoising method based on gravity center and chaos degree. The proposed interpolation method ensures that the invoice image keeps features well after scaling. The flippable pixels evaluation mechanism ensures that the pixels keep better connectivity and smoothness and the pattern has highest structural similarity after flipping. The proposed denoising method makes invoice font image smoother and fiter for human vision. Experiments show that the proposed flipping method not only keeps the invoice font structure well but also improves watermarking capacity.

  1. Design optimization of pixel sensors using device simulations for the phase-II CMS tracker upgrade

    NASA Astrophysics Data System (ADS)

    Jain, G.; Bhardwaj, A.; Dalal, R.; Eber, R.; Eichorn, T.; Fernandez, M.; Lalwani, K.; Messineo, A.; Palomo, F. R.; Peltola, T.; Printz, M.; Ranjan, K.; Villa, I.; Hidalgo, S.

    2016-07-01

    In order to address the problems caused by the harsh radiation environment during the high luminosity phase of the LHC (HL-LHC), all silicon tracking detectors (pixels and strips) in the CMS experiment will undergo an upgrade. And so to develop radiation hard pixel sensors, simulations have been performed using the 2D TCAD device simulator, SILVACO, to obtain design parameters. The effect of various design parameters like pixel size, pixel depth, implant width, metal overhang, p-stop concentration, p-stop depth and bulk doping density on the leakage current and critical electric field are studied for both non-irradiated as well as irradiated pixel sensors. These 2D simulation results of planar pixels are useful for providing insight into the behaviour of non-irradiated and irradiated silicon pixel sensors and further work on 3D simulation is underway.

  2. A new pixels flipping method for huge watermarking capacity of the invoice font image.

    PubMed

    Li, Li; Hou, Qingzheng; Lu, Jianfeng; Xu, Qishuai; Dai, Junping; Mao, Xiaoyang; Chang, Chin-Chen

    2014-01-01

    Invoice printing just has two-color printing, so invoice font image can be seen as binary image. To embed watermarks into invoice image, the pixels need to be flipped. The more huge the watermark is, the more the pixels need to be flipped. We proposed a new pixels flipping method in invoice image for huge watermarking capacity. The pixels flipping method includes one novel interpolation method for binary image, one flippable pixels evaluation mechanism, and one denoising method based on gravity center and chaos degree. The proposed interpolation method ensures that the invoice image keeps features well after scaling. The flippable pixels evaluation mechanism ensures that the pixels keep better connectivity and smoothness and the pattern has highest structural similarity after flipping. The proposed denoising method makes invoice font image smoother and fiter for human vision. Experiments show that the proposed flipping method not only keeps the invoice font structure well but also improves watermarking capacity. PMID:25489606

  3. Extraction of electrical characteristics from pixels of multifrequency EIT images.

    PubMed

    Fitzgerald, A J; Thomas, B J; Cornish, B H; Michael, G J; Ward, L C

    1997-05-01

    Computer modelling has shown that electrical characteristics of individual pixels may be extracted from within multiple-frequency electrical impedance tomography (MFEIT) images formed using a reference data set obtained from a purely resistive, homogeneous medium. In some applications it is desirable to extract the electrical characteristics of individual pixels from images where a purely resistive, homogeneous reference data set is not available. One such application of the technique of MFEIT is to allow the acquisition of in vivo images using reference data sets obtained from a non-homogeneous medium with a reactive component. However, the reactive component of the reference data set introduces difficulties with the extraction of the true electrical characteristics from the image pixels. This study was a preliminary investigation of a technique to extract electrical parameters from multifrequency images when the reference data set has a reactive component. Unlike the situation in which a homogeneous, resistive data set is available, it is not possible to obtain the impedance and phase information directly from the image pixel values of the MFEIT images data set, as the phase of the reactive reference is not known. The method reported here to extract the electrical characteristics (the Cole-Cole plot) initially assumes that this phase angle is zero. With this assumption, an impedance spectrum can be directly extracted from the image set. To obtain the true Cole-Cole plot a correction must be applied to account for the inherent rotation of the extracted impedance spectrum about the origin, which is a result of the assumption. This work shows that the angle of rotation associated with the reactive component of the reference data set may be determined using a priori knowledge of the distribution of frequencies of the Cole-Cole plot. Using this angle of rotation, the true Cole-Cole plot can be obtained from the impedance spectrum extracted from the MFEIT image data

  4. Independent pixel and Monte Carlo estimates of stratocumulus albedo

    NASA Technical Reports Server (NTRS)

    Cahalan, Robert F.; Ridgway, William; Wiscombe, Warren J.; Gollmer, Steven; HARSHVARDHAN

    1994-01-01

    Monte Carlo radiative transfer methods are employed here to estimate the plane-parallel albedo bias for marine stratocumulus clouds. This is the bias in estimates of the mesoscale-average albedo, which arises from the assumption that cloud liquid water is uniformly distributed. The authors compare such estimates with those based on a more realistic distribution generated from a fractal model of marine stratocumulus clouds belonging to the class of 'bounded cascade' models. In this model the cloud top and base are fixed, so that all variations in cloud shape are ignored. The model generates random variations in liquid water along a single horizontal direction, forming fractal cloud streets while conserving the total liquid water in the cloud field. The model reproduces the mean, variance, and skewness of the vertically integrated cloud liquid water, as well as its observed wavenumber spectrum, which is approximately a power law. The Monte Carlo method keeps track of the three-dimensional paths solar photons take through the cloud field, using a vectorized implementation of a direct technique. The simplifications in the cloud field studied here allow the computations to be accelerated. The Monte Carlo results are compared to those of the independent pixel approximation, which neglects net horizontal photon transport. Differences between the Monte Carlo and independent pixel estimates of the mesoscale-average albedo are on the order of 1% for conservative scattering, while the plane-parallel bias itself is an order of magnitude larger. As cloud absorption increases, the independent pixel approximation agrees even more closely with the Monte Carlo estimates. This result holds for a wide range of sun angles and aspect ratios. Thus, horizontal photon transport can be safely neglected in estimates of the area-average flux for such cloud models. This result relies on the rapid falloff of the wavenumber spectrum of stratocumulus, which ensures that the smaller

  5. Position-Sensitive Nuclear Spectroscopy with Pixel Detectors

    SciTech Connect

    Granja, Carlos; Vykydal, Zdenek; Jakubek, Jan; Pospisil, Stanislav

    2007-10-26

    State-of-the-art hybrid semiconductor pixel detectors such as Medipix2 are suitable for energy- and position-sensitive nuclear spectroscopy. In addition to excellent energy- and spatial-resolution, these devices can operate in spectroscopic, single-quantum counting and/or on-line tracking mode. A devoted compact USB-readout interface provides functionality and ease of operation. The compact and versatile Medipix2/USB radiation camera provides visualization, vacuum and room-temperature operation as a real-time portable active nuclear emulsion.

  6. Monolithic pixel detectors in a deep submicron SOI process

    SciTech Connect

    Deptuch, Grzegorz; /Fermilab

    2009-10-01

    A compact charge-signal processing chain, composed of a two-stage semi-gaussian preamplifier-signal shaping filter, a discriminator and a binary counter, implemented in a prototype pixel detector using 0.20 {micro}m CMOS Silicon on Insulator process, is presented. The gain of the analog chain was measured 0.76 V/fC at the signal peaking time about 300 ns and the equivalent noise charge referred to the input of 80 e{sup -1}.

  7. A CMOS Active Pixel Sensor for Charged Particle Detection

    SciTech Connect

    Matis, Howard S.; Bieser, Fred; Kleinfelder, Stuart; Rai, Gulshan; Retiere, Fabrice; Ritter, Hans George; Singh, Kunal; Wurzel, Samuel E.; Wieman, Howard; Yamamoto, Eugene

    2002-12-02

    Active Pixel Sensor (APS) technology has shown promise for next-generation vertex detectors. This paper discusses the design and testing of two generations of APS chips. Both are arrays of 128 by 128 pixels, each 20 by 20 {micro}m. Each array is divided into sub-arrays in which different sensor structures (4 in the first version and 16 in the second) and/or readout circuits are employed. Measurements of several of these structures under Fe{sup 55} exposure are reported. The sensors have also been irradiated by 55 MeV protons to test for radiation damage. The radiation increased the noise and reduced the signal. The noise can be explained by shot noise from the increased leakage current and the reduction in signal is due to charge being trapped in the epi layer. Nevertheless, the radiation effect is small for the expected exposures at RHIC and RHIC II. Finally, we describe our concept for mechanically supporting a thin silicon wafer in an actual detector.

  8. A generic readout environment for prototype pixel detectors

    NASA Astrophysics Data System (ADS)

    Turqueti, Marcos; Rivera, Ryan; Prosser, Alan; Kwan, Simon

    2010-11-01

    Pixel detectors for experimental particle physics research have been implemented with a variety of readout formats and potentially generate massive amounts of data. Examples include the PSI46 device for the Compact Muon Solenoid (CMS) experiment which implements an analog readout, the Fermilab FPIX2.1 device with a digital readout, and the Fermilab Vertically Integrated Pixel device. The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory has developed a data acquisition system flexible and powerful enough to meet the various needs of these devices to support laboratory test bench as well as test beam applications. The system is called CAPTAN (Compact And Programmable daTa Acquisition Node) and is characterized by its flexibility, versatility and scalability by virtue of several key architectural features. These include a vertical bus that permits the user to stack multiple boards, a gigabit Ethernet link that permits high speed communications to the system and a core group of boards that provide specific processing and readout capabilities for the system. System software based on distributed computing techniques supports an expandable network of CAPTANs. In this paper, we describe the system architecture and give an overview of its capabilities.

  9. Pixelated transmission-mode diamond X-ray detector

    PubMed Central

    Zhou, Tianyi; Ding, Wenxiang; Gaowei, Mengjia; De Geronimo, Gianluigi; Bohon, Jen; Smedley, John; Muller, Erik

    2015-01-01

    Fabrication and testing of a prototype transmission-mode pixelated diamond X-ray detector (pitch size 60–100 µm), designed to simultaneously measure the flux, position and morphology of an X-ray beam in real time, are described. The pixel density is achieved by lithographically patterning vertical stripes on the front and horizontal stripes on the back of an electronic-grade chemical vapor deposition single-crystal diamond. The bias is rotated through the back horizontal stripes and the current is read out on the front vertical stripes at a rate of ∼1 kHz, which leads to an image sampling rate of ∼30 Hz. This novel signal readout scheme was tested at beamline X28C at the National Synchrotron Light Source (white beam, 5–15 keV) and at beamline G3 at the Cornell High Energy Synchrotron Source (monochromatic beam, 11.3 keV) with incident beam flux ranges from 1.8 × 10−2 to 90 W mm−2. Test results show that the novel detector provides precise beam position (positional noise within 1%) and morphology information (error within 2%), with an additional software-controlled single channel mode providing accurate flux measurement (fluctuation within 1%). PMID:26524304

  10. Pixelated transmission-mode diamond X-ray detector.

    PubMed

    Zhou, Tianyi; Ding, Wenxiang; Gaowei, Mengjia; De Geronimo, Gianluigi; Bohon, Jen; Smedley, John; Muller, Erik

    2015-11-01

    Fabrication and testing of a prototype transmission-mode pixelated diamond X-ray detector (pitch size 60-100 µm), designed to simultaneously measure the flux, position and morphology of an X-ray beam in real time, are described. The pixel density is achieved by lithographically patterning vertical stripes on the front and horizontal stripes on the back of an electronic-grade chemical vapor deposition single-crystal diamond. The bias is rotated through the back horizontal stripes and the current is read out on the front vertical stripes at a rate of ∼ 1 kHz, which leads to an image sampling rate of ∼ 30 Hz. This novel signal readout scheme was tested at beamline X28C at the National Synchrotron Light Source (white beam, 5-15 keV) and at beamline G3 at the Cornell High Energy Synchrotron Source (monochromatic beam, 11.3 keV) with incident beam flux ranges from 1.8 × 10(-2) to 90 W mm(-2). Test results show that the novel detector provides precise beam position (positional noise within 1%) and morphology information (error within 2%), with an additional software-controlled single channel mode providing accurate flux measurement (fluctuation within 1%).

  11. Monolithic Active Pixel Matrix with Binary Counters (MAMBO) ASIC

    SciTech Connect

    Khalid, Farah F.; Deptuch, Grzegorz; Shenai, Alpana; Yarema, Raymond J.; /Fermilab

    2010-11-01

    Monolithic Active Matrix with Binary Counters (MAMBO) is a counting ASIC designed for detecting and measuring low energy X-rays from 6-12 keV. Each pixel contains analogue functionality implemented with a charge preamplifier, CR-RC{sup 2} shaper and a baseline restorer. It also contains a window comparator which can be trimmed by 4 bit DACs to remove systematic offsets. The hits are registered by a 12 bit ripple counter which is reconfigured as a shift register to serially output the data from the entire ASIC. Each pixel can be tested individually. Two diverse approaches have been used to prevent coupling between the detector and electronics in MAMBO III and MAMBO IV. MAMBO III is a 3D ASIC, the bottom ASIC consists of diodes which are connected to the top ASIC using {mu}-bump bonds. The detector is decoupled from the electronics by physically separating them on two tiers and using several metal layers as a shield. MAMBO IV is a monolithic structure which uses a nested well approach to isolate the detector from the electronics. The ASICs are being fabricated using the SOI 0.2 {micro}m OKI process, MAMBO III is 3D bonded at T-Micro and MAMBO IV nested well structure was developed in collaboration between OKI and Fermilab.

  12. Memory color assisted illuminant estimation through pixel clustering

    NASA Astrophysics Data System (ADS)

    Zhang, Heng; Quan, Shuxue

    2010-01-01

    The under constrained nature of illuminant estimation determines that in order to resolve the problem, certain assumptions are needed, such as the gray world theory. Including more constraints in this process may help explore the useful information in an image and improve the accuracy of the estimated illuminant, providing that the constraints hold. Based on the observation that most personal images have contents of one or more of the following categories: neutral objects, human beings, sky, and plants, we propose a method for illuminant estimation through the clustering of pixels of gray and three dominant memory colors: skin tone, sky blue, and foliage green. Analysis shows that samples of the above colors cluster around small areas under different illuminants and their characteristics can be used to effectively detect pixels falling into each of the categories. The algorithm requires the knowledge of the spectral sensitivity response of the camera, and a spectral database consisted of the CIE standard illuminants and reflectance or radiance database of samples of the above colors.

  13. pPXF: Penalized Pixel-Fitting stellar kinematics extraction

    NASA Astrophysics Data System (ADS)

    Cappellari, Michele

    2012-10-01

    pPXF is an IDL (and free GDL or FL) program which extracts the stellar kinematics or stellar population from absorption-line spectra of galaxies using the Penalized Pixel-Fitting method (pPXF) developed by Cappellari & Emsellem (2004, PASP, 116, 138). Additional features implemented in the pPXF routine include: Optimal template: Fitted together with the kinematics to minimize template-mismatch errors. Also useful to extract gas kinematics or derive emission-corrected line-strengths indexes. One can use synthetic templates to study the stellar population of galaxies via "Full Spectral Fitting" instead of using traditional line-strengths.Regularization of templates weights: To reduce the noise in the recovery of the stellar population parameters and attach a physical meaning to the output weights assigned to the templates in term of the star formation history (SFH) or metallicity distribution of an individual galaxy.Iterative sigma clipping: To clean the spectra from residual bad pixels or cosmic rays.Additive/multiplicative polynomials: To correct low frequency continuum variations. Also useful for calibration purposes.

  14. The pixel detector for the CMS phase-II upgrade

    NASA Astrophysics Data System (ADS)

    Dinardo, M. E.

    2015-04-01

    The high luminosity phase of the Large Hadron Collider (HL-LHC) requires a major pixel detector R&D effort to develop both readout chip and sensor that are capable to withstand unprecedented extremely high radiation. The target integrated luminosity of 3000 fb-1, that the HL-LHC is expected to deliver over about 10 years of operation, translates into a hadron fluence of 2×1016 1 MeV eq.n. / cm2, or equivalently 10 MGy of radiation dose in silicon, at about 3 cm from the interaction region where the first layer of the pixel detector could be located. The CMS collaboration has undertaken two baseline sensor R&D programs on thin n-on-p planar and 3D silicon sensor technologies. Together with the ATLAS collaboration it has also been established a common R&D effort for the development of the readout chip in the 65 nm CMOS technology. Status, progresses, and prospects of the CMS R&D effort are presented and discussed in this article.

  15. Multilayer fluorescence imaging on a single-pixel detector.

    PubMed

    Guo, Kaikai; Jiang, Shaowei; Zheng, Guoan

    2016-07-01

    A critical challenge for fluorescence imaging is the loss of high frequency components in the detection path. Such a loss can be related to the limited numerical aperture of the detection optics, aberrations of the lens, and tissue turbidity. In this paper, we report an imaging scheme that integrates multilayer sample modeling, ptychography-inspired recovery procedures, and lensless single-pixel detection to tackle this challenge. In the reported scheme, we directly placed a 3D sample on top of a single-pixel detector. We then used a known mask to generate speckle patterns in 3D and scanned this known mask to different positions for sample illumination. The sample was then modeled as multiple layers and the captured 1D fluorescence signals were used to recover multiple sample images along the z axis. The reported scheme may find applications in 3D fluorescence sectioning, time-resolved and spectrum-resolved imaging. It may also find applications in deep-tissue fluorescence imaging using the memory effect. PMID:27446679

  16. A new design for the gas pixel detector

    NASA Astrophysics Data System (ADS)

    Muleri, Fabio; Bellazzini, Ronaldo; Brez, Alessandro; Costa, Enrico; Fabiani, Sergio; Minuti, Massimo; Pinchera, Michele; Rubini, Alda; Soffitta, Paolo; Spandre, Gloria

    2012-09-01

    The Gas Pixel Detector, developed and continuously improved by Pisa INFN in collaboration with INAF-IAPS, can visualize the tracks produced within a low Z gas by photoelectrons of few keV. By reconstructing the impact point and the original direction of the photoelectrons, the GPD can measure the linear polarization of X-rays, while preserving the information on the absorption point, the energy and the time of arrival of individual photons. The Gas Pixel Detector filled with He-DME mixture at 1 bar is sensitive in the 2-10 keV energy range and this configuration has been the basis of a number of mission proposals, such as POLARIX or XPOL on-board XEUS/IXO, or the X-ray Imaging Polarimetry Explorer (XIPE) submitted in response to ESA small mission call in 2012. We have recently improved the design by modifying the geometry of the absorption cell to minimize any systematic effect which could leave a residual polarization signal for non polarized source. We report on the testing of this new concept with preliminary results on the new design performance.

  17. Large format, small pixel pitch and hot detectors at SOFRADIR

    NASA Astrophysics Data System (ADS)

    Reibel, Y.; Rouvie, A.; Nedelcu, A.; Augey, T.; Pere-Laperne, N.; Rubaldo, L.; Billon-Lanfrey, D.; Gravrand, O.; Rothman, J.; Destefanis, G.

    2013-10-01

    Recently Sofradir joined a very small circle of IR detector manufacturers with expertise every aspect of the cooled and uncooled IR technologies, all under one roof by consolidating all IR technologies available in France. These different technologies are complementary and are used depending of the needs of the applications mainly concerning the detection range needs as well as their ability to detect in bad weather environmental conditions. SNAKE (InGaAs) and SCORPIO LW (MCT) expand Sofradir's line of small pixel pitch TV format IR detectors from the mid-wavelength to the short and long wavelengths. Our dual band MW-LW QWIP detectors (25μm, 384×288 pixels) benefit to tactical platforms giving an all-weather performance and increasing flexibility in the presence of battlefield obscurants. In parallel we have been pursuing further infrared developments on future MWIR detectors, such as the VGA format HOT detector that consumes 2W and the 10μm pitch IR detector which gives us a leading position in innovation. These detectors are designed for long-range surveillance equipment, commander or gunner sights, ground-to-ground missile launchers and other applications that require higher resolution and sensitivity to improve reconnaissance and target identification. This paper discusses the system level performance in each detector type.

  18. Capacitively coupled hybrid pixel assemblies for the CLIC vertex detector

    NASA Astrophysics Data System (ADS)

    Tehrani, N. Alipour; Arfaoui, S.; Benoit, M.; Dannheim, D.; Dette, K.; Hynds, D.; Kulis, S.; Perić, I.; Petrič, M.; Redford, S.; Sicking, E.; Valerio, P.

    2016-07-01

    The vertex detector at the proposed CLIC multi-TeV linear e+e- collider must have minimal material content and high spatial resolution, combined with accurate time-stamping to cope with the expected high rate of beam-induced backgrounds. One of the options being considered is the use of active sensors implemented in a commercial high-voltage CMOS process, capacitively coupled to hybrid pixel ASICs. A prototype of such an assembly, using two custom designed chips (CCPDv3 as active sensor glued to a CLICpix readout chip), has been characterised both in the lab and in beam tests at the CERN SPS using 120 GeV/c positively charged hadrons. Results of these characterisation studies are presented both for single and dual amplification stages in the active sensor, where efficiencies of greater than 99% have been achieved at -60 V substrate bias, with a single hit resolution of 6.1 μm . Pixel cross-coupling results are also presented, showing the sensitivity to placement precision and planarity of the glue layer.

  19. Amplifier based broadband pixel for sub-millimeter wave imaging

    NASA Astrophysics Data System (ADS)

    Sarkozy, Stephen; Drewes, Jonathan; Leong, Kevin M. K. H.; Lai, Richard; Mei, X. B. (Gerry); Yoshida, Wayne; Lange, Michael D.; Lee, Jane; Deal, William R.

    2012-09-01

    Broadband sub-millimeter wave technology has received significant attention for potential applications in security, medical, and military imaging. Despite theoretical advantages of reduced size, weight, and power compared to current millimeter wave systems, sub-millimeter wave systems have been hampered by a fundamental lack of amplification with sufficient gain and noise figure properties. We report a broadband pixel operating from 300 to 340 GHz, biased off a single 2 V power supply. Over this frequency range, the amplifiers provide > 40 dB gain and <8 dB noise figure, representing the current state-of-art performance capabilities. This pixel is enabled by revolutionary enhancements to indium phosphide (InP) high electron mobility transistor technology, based on a sub-50 nm gate and indium arsenide composite channel with a projected maximum oscillation frequency fmax>1.0 THz. The first sub-millimeter wave-based images using active amplification are demonstrated as part of the Joint Improvised Explosive Device Defeat Organization Longe Range Personnel Imager Program. This development and demonstration may bring to life future sub-millimeter-wave and THz applications such as solutions to brownout problems, ultra-high bandwidth satellite communication cross-links, and future planetary exploration missions.

  20. Photon crosstalk in pixel array for x-ray imaging

    NASA Astrophysics Data System (ADS)

    Kim, Myung Soo; Kim, Giyoon; Kang, Dong-uk; Lee, Daehee; Cho, Gyuseong

    2014-09-01

    A large-area X-ray CMOS image sensor (LXCIS) is widely used in mammography, non-destructive inspection, and animal CT. For LXCIS, in spite of weakness such as low spatial and energy resolution, a Indirect method using scintillator like CsI(Tl) or Gd2O2S is still well-used because of low cost and easy manufacture. A photo-diode for X-ray imaging has large area about 50 ~ 200 um as compared with vision image sensors. That is because X-ray has feature of straight and very small light emission of a scintillator. Moreover, notwithstanding several structure like columnar, the scintillator still emit a diffusible light. This diffusible light from scintillator can make spatial crosstalk in X-ray photodiode array because of a large incidence angle. Moreover, comparing with vision image sensors, X-ray sensor doesn't have micro lens for gathering the photons to photo-diode. In this study, we simulated the affection of spatial crosstalk in X-ray sensor by comparing optical sensor. Additionally, the chip, which was fabricated in 0.18 um 1P5M process by Hynix in Korea, was tested to know the effect of spatial crosstalk by changing design parameters. From these works, we found out that spatial crosstalk is affected by pixel pitch, incident angle of photons, and micro lens on each pixels.

  1. The effect of split pixel HDR image sensor technology on MTF measurements

    NASA Astrophysics Data System (ADS)

    Deegan, Brian M.

    2014-03-01

    Split-pixel HDR sensor technology is particularly advantageous in automotive applications, because the images are captured simultaneously rather than sequentially, thereby reducing motion blur. However, split pixel technology introduces artifacts in MTF measurement. To achieve a HDR image, raw images are captured from both large and small sub-pixels, and combined to make the HDR output. In some cases, a large sub-pixel is used for long exposure captures, and a small sub-pixel for short exposures, to extend the dynamic range. The relative size of the photosensitive area of the pixel (fill factor) plays a very significant role in the output MTF measurement. Given an identical scene, the MTF will be significantly different, depending on whether you use the large or small sub-pixels i.e. a smaller fill factor (e.g. in the short exposure sub-pixel) will result in higher MTF scores, but significantly greater aliasing. Simulations of split-pixel sensors revealed that, when raw images from both sub-pixels are combined, there is a significant difference in rising edge (i.e. black-to-white transition) and falling edge (white-to-black) reproduction. Experimental results showed a difference of ~50% in measured MTF50 between the falling and rising edges of a slanted edge test chart.

  2. Hardware solutions for the 65k pixel X-ray camera module of 75 μm pixel size

    NASA Astrophysics Data System (ADS)

    Kasinski, K.; Maj, P.; Grybos, P.; Koziol, A.

    2016-02-01

    We present three hardware solutions designed for a detector module built with a 2 cm × 2 cm hybrid pixel detector built from a single 320 or 450 μ m thick silicon sensor designed and fabricated by Hamamatsu and two UFXC32k readout integrated circuits (128 × 256 pixels with 75μ m pitch, designed in CMOS 130 nm at AGH-UST). The chips work in a single photon counting mode and provide ultra-fast X-ray imaging. The presented hardware modules are designed according to requirements of various tests and applications: ṡDevice A: a fast and flexible system for tests with various radiation sources. ṡDevice B: a standalone, all-in-one imaging device providing three standard interfaces (USB 2.0, Ethernet, Camera Link) and up to 640 MB/s bandwidth. ṡDevice C: a prototype large-area imaging system. The paper shows the readout system structure for each case with highlighted circuit board designs with details on power distribution and cooling on both FR4 and LTCC (low temperature co-fired ceramic) based circuits.

  3. Integrated Lens Antennas for Multi-Pixel Receivers

    NASA Technical Reports Server (NTRS)

    Lee, Choonsup; Chattopadhyay, Goutam

    2011-01-01

    Future astrophysics and planetary experiments are expected to require large focal plane arrays with thousands of detectors. Feedhorns have excellent performance, but their mass, size, fabrication challenges, and expense become prohibitive for very large focal plane arrays. Most planar antenna designs produce broad beam patterns, and therefore require additional elements for efficient coupling to the telescope optics, such as substrate lenses or micromachined horns. An antenna array with integrated silicon microlenses that can be fabricated photolithographically effectively addresses these issues. This approach eliminates manual assembly of arrays of lenses and reduces assembly errors and tolerances. Moreover, an antenna array without metallic horns will reduce mass of any planetary instrument significantly. The design has a monolithic array of lens-coupled, leaky-wave antennas operating in the millimeter- and submillimeter-wave frequencies. Electromagnetic simulations show that the electromagnetic fields in such lens-coupled antennas are mostly confined in approximately 12 15 . This means that one needs to design a small-angle sector lens that is much easier to fabricate using standard lithographic techniques, instead of a full hyper-hemispherical lens. Moreover, this small-angle sector lens can be easily integrated with the antennas in an array for multi-pixel imager and receiver implementation. The leaky antenna is designed using double-slot irises and fed with TE10 waveguide mode. The lens implementation starts with a silicon substrate. Photoresist with appropriate thickness (optimized for the lens size) is spun on the substrate and then reflowed to get the desired lens structure. An antenna array integrated with individual lenses for higher directivity and excellent beam profile will go a long way in realizing multi-pixel arrays and imagers. This technology will enable a new generation of compact, low-mass, and highly efficient antenna arrays for use in multi-pixel

  4. Quantification and adjustment of pixel-locking in particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Hearst, R. J.; Ganapathisubramani, B.

    2015-10-01

    A quantification metric is provided to determine the degree to which a particle image velocimetry data set is pixel-locked. The metric is calculated by integrating the histogram equalization transfer function and normalizing by the worst-case scenario to return the percentage pixel-locked. When this metric is calculated for each position in the vector field, it is shown that pixel-locking is non-uniform across the field. Hence, pixel-locking adjustments should be made on a vector-by-vector basis rather than uniformly across a field, although the latter is the common practice. A methodology is provided to compensate for the effects of pixel-locking on a vector-by-vector basis. This includes applying a Gaussian filter directly to the images, processing the images with window deformation, ensuring the vector fields are in pixel displacements, applying histogram equalization calculated at each vector coordinate, and mapping the adjusted vector fields to physical space.

  5. A Wideband Circularly Polarized Pixelated Dielectric Resonator Antenna.

    PubMed

    Trinh-Van, Son; Yang, Youngoo; Lee, Kang-Yoon; Hwang, Keum Cheol

    2016-01-01

    The design of a wideband circularly polarized pixelated dielectric resonator antenna using a real-coded genetic algorithm (GA) is presented for far-field wireless power transfer applications. The antenna consists of a dielectric resonator (DR) which is discretized into 8 × 8 grid DR bars. The real-coded GA is utilized to estimate the optimal heights of the 64 DR bars to realize circular polarization. The proposed antenna is excited by a narrow rectangular slot etched on the ground plane. A prototype of the proposed antenna is fabricated and tested. The measured -10 dB reflection and 3 dB axial ratio bandwidths are 32.32% (2.62-3.63 GHz) and 14.63% (2.85-3.30 GHz), respectively. A measured peak gain of 6.13 dBic is achieved at 3.2 GHz. PMID:27563897

  6. Measurement of pixel response functions of a fully depleted CCD

    NASA Astrophysics Data System (ADS)

    Kobayashi, Yukiyasu; Niwa, Yoshito; Yano, Taihei; Gouda, Naoteru; Hara, Takuji; Yamada, Yoshiyuki

    2014-07-01

    We describe the measurement of detailed and precise Pixel Response Functions (PRFs) of a fully depleted CCD. Measurements were performed under different physical conditions, such as different wavelength light sources or CCD operating temperatures. We determined the relations between these physical conditions and the forms of the PRF. We employ two types of PRFs: one is the model PRF (mPRF) that can represent the shape of a PRF with one characteristic parameter and the other is the simulated PRF (sPRF) that is the resultant PRF from simulating physical phenomena. By using measured, model, and simulated PRFs, we determined the relations between operational parameters and the PRFs. Using the obtained relations, we can now estimate a PRF under conditions that will be encountered during the course of Nano-JASMINE observations. These estimated PRFs will be utilized in the analysis of the Nano-JASMINE data.

  7. A semiconductor radiation imaging pixel detector for space radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Kroupa, Martin; Bahadori, Amir; Campbell-Ricketts, Thomas; Empl, Anton; Hoang, Son Minh; Idarraga-Munoz, John; Rios, Ryan; Semones, Edward; Stoffle, Nicholas; Tlustos, Lukas; Turecek, Daniel; Pinsky, Lawrence

    2015-07-01

    Progress in the development of high-performance semiconductor radiation imaging pixel detectors based on technologies developed for use in high-energy physics applications has enabled the development of a completely new generation of compact low-power active dosimeters and area monitors for use in space radiation environments. Such detectors can provide real-time information concerning radiation exposure, along with detailed analysis of the individual particles incident on the active medium. Recent results from the deployment of detectors based on the Timepix from the CERN-based Medipix2 Collaboration on the International Space Station (ISS) are reviewed, along with a glimpse of developments to come. Preliminary results from Orion MPCV Exploration Flight Test 1 are also presented.

  8. Nano-fabricated pixelated micropolarizer array for visible imaging polarimetry

    SciTech Connect

    Zhang, Zhigang; Cheng, Teng; Qiu, Kang; Zhang, Qingchuan E-mail: wgchu@nanoctr.cn; Wu, Xiaoping; Dong, Fengliang; Chu, Weiguo E-mail: wgchu@nanoctr.cn

    2014-10-15

    Pixelated micropolarizer array (PMA) is a novel concept for real-time visible imaging polarimetry. A 320 × 240 aluminum PMA fabricated by electron beam lithography is described in this paper. The period, duty ratio, and depth of the grating are 140 nm, 0.5, and 100 nm, respectively. The units are standard square structures and the metal nanowires of the grating are collimating and uniformly thick. The extinction ratio of 75 and the maximum polarization transmittance of 78.8% demonstrate that the PMA is suitable for polarization imaging. When the PMA is applied to real-time polarization imaging, the degree of linear polarization image and the angle of linear polarization image are calculated from a single frame image. The polarized target object is highlighted from the unpolarized background, and the surface contour of the target object can be reflected by the polarization angle.

  9. Simulation of the dynamic inefficiency of the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Bartók, M.

    2015-05-01

    The Pixel Detector is the innermost part of the CMS Tracker. It therefore has to prevail in the harshest environment in terms of particle fluence and radiation. There are several mechanisms that may decrease the efficiency of the detector. These are mainly caused by data acquisition (DAQ) problems and/or Single Event Upsets (SEU). Any remaining efficiency loss is referred to as the dynamic inefficiency. It is caused by various mechanisms inside the Readout Chip (ROC) and depends strongly on the data occupancy. In the 2012 data, at high values of instantaneous luminosity the inefficiency reached 2% (in the region closest to the interaction point) which is not negligible. In the 2015 run higher instantaneous luminosity is expected, which will result in lower efficiencies; therefore this effect needs to be understood and simulated. A data-driven method has been developed to simulate dynamic inefficiency, which has been shown to successfully simulate the effects.

  10. A semiconductor radiation imaging pixel detector for space radiation dosimetry.

    PubMed

    Kroupa, Martin; Bahadori, Amir; Campbell-Ricketts, Thomas; Empl, Anton; Hoang, Son Minh; Idarraga-Munoz, John; Rios, Ryan; Semones, Edward; Stoffle, Nicholas; Tlustos, Lukas; Turecek, Daniel; Pinsky, Lawrence

    2015-07-01

    Progress in the development of high-performance semiconductor radiation imaging pixel detectors based on technologies developed for use in high-energy physics applications has enabled the development of a completely new generation of compact low-power active dosimeters and area monitors for use in space radiation environments. Such detectors can provide real-time information concerning radiation exposure, along with detailed analysis of the individual particles incident on the active medium. Recent results from the deployment of detectors based on the Timepix from the CERN-based Medipix2 Collaboration on the International Space Station (ISS) are reviewed, along with a glimpse of developments to come. Preliminary results from Orion MPCV Exploration Flight Test 1 are also presented. PMID:26256630

  11. CMOS Monolithic Active Pixel Sensors (MAPS): Developments and future outlook

    NASA Astrophysics Data System (ADS)

    Turchetta, R.; Fant, A.; Gasiorek, P.; Esbrand, C.; Griffiths, J. A.; Metaxas, M. G.; Royle, G. J.; Speller, R.; Venanzi, C.; van der Stelt, P. F.; Verheij, H.; Li, G.; Theodoridis, S.; Georgiou, H.; Cavouras, D.; Hall, G.; Noy, M.; Jones, J.; Leaver, J.; Machin, D.; Greenwood, S.; Khaleeq, M.; Schulerud, H.; Østby, J. M.; Triantis, F.; Asimidis, A.; Bolanakis, D.; Manthos, N.; Longo, R.; Bergamaschi, A.

    2007-12-01

    Re-invented in the early 1990s, on both sides of the Atlantic, Monolithic Active Pixel Sensors (MAPS) in a CMOS technology are today the most sold solid-state imaging devices, overtaking the traditional technology of Charge-Coupled Devices (CCD). The slow uptake of CMOS MAPS started with low-end applications, for example web-cams, and is slowly pervading the high-end applications, for example in prosumer digital cameras. Higher specifications are required for scientific applications: very low noise, high speed, high dynamic range, large format and radiation hardness are some of these requirements. This paper will present a brief overview of the CMOS Image Sensor technology and of the requirements for scientific applications. As an example, a sensor for X-ray imaging will be presented. This sensor was developed within a European FP6 Consortium, intelligent imaging sensors (I-ImaS).

  12. Monolithic active pixel radiation detector with shielding techniques

    DOEpatents

    Deptuch, Grzegorz W.

    2016-09-06

    A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

  13. Interactive Isogeometric Volume Visualization with Pixel-Accurate Geometry.

    PubMed

    Fuchs, Franz G; Hjelmervik, Jon M

    2016-02-01

    A recent development, called isogeometric analysis, provides a unified approach for design, analysis and optimization of functional products in industry. Traditional volume rendering methods for inspecting the results from the numerical simulations cannot be applied directly to isogeometric models. We present a novel approach for interactive visualization of isogeometric analysis results, ensuring correct, i.e., pixel-accurate geometry of the volume including its bounding surfaces. The entire OpenGL pipeline is used in a multi-stage algorithm leveraging techniques from surface rendering, order-independent transparency, as well as theory and numerical methods for ordinary differential equations. We showcase the efficiency of our approach on different models relevant to industry, ranging from quality inspection of the parametrization of the geometry, to stress analysis in linear elasticity, to visualization of computational fluid dynamics results. PMID:26731454

  14. Interactive Isogeometric Volume Visualization with Pixel-Accurate Geometry.

    PubMed

    Fuchs, Franz G; Hjelmervik, Jon M

    2016-02-01

    A recent development, called isogeometric analysis, provides a unified approach for design, analysis and optimization of functional products in industry. Traditional volume rendering methods for inspecting the results from the numerical simulations cannot be applied directly to isogeometric models. We present a novel approach for interactive visualization of isogeometric analysis results, ensuring correct, i.e., pixel-accurate geometry of the volume including its bounding surfaces. The entire OpenGL pipeline is used in a multi-stage algorithm leveraging techniques from surface rendering, order-independent transparency, as well as theory and numerical methods for ordinary differential equations. We showcase the efficiency of our approach on different models relevant to industry, ranging from quality inspection of the parametrization of the geometry, to stress analysis in linear elasticity, to visualization of computational fluid dynamics results.

  15. Spatial optical phase-modulating metadevice with subwavelength pixelation.

    PubMed

    Cencillo-Abad, Pablo; Plum, Eric; Rogers, Edward T F; Zheludev, Nikolay I

    2016-08-01

    Dynamic control over optical wavefronts enables focusing, diffraction and redirection of light on demand, however, sub-wavelength resolution is required to avoid unwanted diffracted beams that are present in commercial spatial light modulators. Here we propose a realistic metadevice that dynamically controls the optical phase of reflected beams with sub-wavelength pixelation in one dimension. Based on reconfigurable metamaterials and nanomembrane technology, it consists of individually moveable metallic nanowire actuators that control the phase of reflected light by modulating the optical path length. We demonstrate that the metadevice can provide on-demand optical wavefront shaping functionalities of diffraction gratings, beam splitters, phase-gradient metasurfaces, cylindrical mirrors and mirror arrays - with variable focal distance and numerical aperture - without unwanted diffraction.

  16. Spatial optical phase-modulating metadevice with subwavelength pixelation.

    PubMed

    Cencillo-Abad, Pablo; Plum, Eric; Rogers, Edward T F; Zheludev, Nikolay I

    2016-08-01

    Dynamic control over optical wavefronts enables focusing, diffraction and redirection of light on demand, however, sub-wavelength resolution is required to avoid unwanted diffracted beams that are present in commercial spatial light modulators. Here we propose a realistic metadevice that dynamically controls the optical phase of reflected beams with sub-wavelength pixelation in one dimension. Based on reconfigurable metamaterials and nanomembrane technology, it consists of individually moveable metallic nanowire actuators that control the phase of reflected light by modulating the optical path length. We demonstrate that the metadevice can provide on-demand optical wavefront shaping functionalities of diffraction gratings, beam splitters, phase-gradient metasurfaces, cylindrical mirrors and mirror arrays - with variable focal distance and numerical aperture - without unwanted diffraction. PMID:27505842

  17. Pixel color feature enhancement for road signs detection

    NASA Astrophysics Data System (ADS)

    Zhang, Qieshi; Kamata, Sei-ichiro

    2010-02-01

    Road signs play an important role in our daily life which used to guide drivers to notice variety of road conditions and cautions. They provide important visual information that can help drivers operating their vehicles in a manner for enhancing traffic safety. The occurrence of some accidents can be reduced by using automatic road signs recognition system which can alert the drivers. This research attempts to develop a warning system to alert the drivers to notice the important road signs early enough to refrain road accidents from happening. For solving this, a non-linear weighted color enhancement method by pixels is presented. Due to the advantage of proposed method, different road signs can be detected from videos effectively. With suitably coefficients and operations, the experimental results have proved that the proposed method is robust, accurate and powerful in road signs detection.

  18. A Wideband Circularly Polarized Pixelated Dielectric Resonator Antenna

    PubMed Central

    Trinh-Van, Son; Yang, Youngoo; Lee, Kang-Yoon; Hwang, Keum Cheol

    2016-01-01

    The design of a wideband circularly polarized pixelated dielectric resonator antenna using a real-coded genetic algorithm (GA) is presented for far-field wireless power transfer applications. The antenna consists of a dielectric resonator (DR) which is discretized into 8 × 8 grid DR bars. The real-coded GA is utilized to estimate the optimal heights of the 64 DR bars to realize circular polarization. The proposed antenna is excited by a narrow rectangular slot etched on the ground plane. A prototype of the proposed antenna is fabricated and tested. The measured −10 dB reflection and 3 dB axial ratio bandwidths are 32.32% (2.62–3.63 GHz) and 14.63% (2.85–3.30 GHz), respectively. A measured peak gain of 6.13 dBic is achieved at 3.2 GHz. PMID:27563897

  19. Transillumination imaging through biological tissue by single-pixel detection

    NASA Astrophysics Data System (ADS)

    Durán, Vicente; Soldevila, Fernando; Irles, Esther; Clemente, Pere; Tajahuerce, Enrique; Andrés, Pedro; Lancis, Jesús

    2015-07-01

    One challenge that has long held the attention of scientists is that of clearly seeing objects hidden by turbid media, as smoke, fog or biological tissue, which has major implications in fields such as remote sensing or early diagnosis of diseases. Here, we combine structured incoherent illumination and bucket detection for imaging an absorbing object completely embedded in a scattering medium. A sequence of low-intensity microstructured light patterns is launched onto the object, whose image is accurately reconstructed through the light fluctuations measured by a single-pixel detector. Our technique is noninvasive, does not require coherent sources, raster scanning nor time-gated detection and benefits from the compressive sensing strategy. As a proof of concept, we experimentally retrieve the image of a transilluminated target both sandwiched between two holographic diffusers and embedded in a 6mm-thick sample of chicken breast.

  20. High-resolution confocal Raman microscopy using pixel reassignment.

    PubMed

    Roider, Clemens; Ritsch-Marte, Monika; Jesacher, Alexander

    2016-08-15

    We present a practical modification of fiber-coupled confocal Raman scanning microscopes that is able to provide high confocal resolution in conjunction with high light collection efficiency. For this purpose, the single detection fiber is replaced by a hexagonal lenslet array in combination with a hexagonally packed round-to-linear multimode fiber bundle. A multiline detector is used to collect individual Raman spectra for each fiber. Data post-processing based on pixel reassignment allows one to improve the lateral resolution by up to 41% compared to a single fiber of equal light collection efficiency. We present results from an experimental implementation featuring seven collection fibers, yielding a resolution improvement of about 30%. We believe that our implementation represents an attractive upgrade for existing confocal Raman microscopes that employ multi-line detectors. PMID:27519099

  1. Signal processing algorithms for staring single pixel hyperspectral sensors

    NASA Astrophysics Data System (ADS)

    Manolakis, Dimitris; Rossacci, Michael; O'Donnell, Erin; D'Amico, Francis M.

    2006-08-01

    Remote sensing of chemical warfare agents (CWA) with stand-off hyperspectral sensors has a wide range of civilian and military applications. These sensors exploit the spectral changes in the ambient photon flux produced thermal emission or absorption after passage through a region containing the CWA cloud. In this work we focus on (a) staring single-pixel sensors that sample their field of view at regular intervals of time to produce a time series of spectra and (b) scanning single or multiple pixel sensors that sample their FOV as they scan. The main objective of signal processing algorithms is to determine if and when a CWA enters the FOV of the sensor. We shall first develop and evaluate algorithms for staring sensors following two different approaches. First, we will assume that no threat information is available and we design an adaptive anomaly detection algorithm to detect a statistically-significant change in the observed spectrum. The algorithm processes the observed spectra sequentially-in-time, estimates adaptively the background, and checks whether the next spectrum differs significantly from the background based on the Mahalanobis distance or the distance from the background subspace. In the second approach, we will assume that we know the spectral signature of the CWA and develop sequential-in-time adaptive matched filter detectors. In both cases, we assume that the sensor starts its operation before the release of the CWA; otherwise, staring at a nearby CWA-free area is required for background estimation. Experimental evaluation and comparison of the proposed algorithms is accomplished using data from a long-wave infrared (LWIR) Fourier transform spectrometer.

  2. 2D Sub-Pixel Disparity Measurement Using QPEC / Medicis

    NASA Astrophysics Data System (ADS)

    Cournet, M.; Giros, A.; Dumas, L.; Delvit, J. M.; Greslou, D.; Languille, F.; Blanchet, G.; May, S.; Michel, J.

    2016-06-01

    In the frame of its earth observation missions, CNES created a library called QPEC, and one of its launcher called Medicis. QPEC / Medicis is a sub-pixel two-dimensional stereo matching algorithm that works on an image pair. This tool is a block matching algorithm, which means that it is based on a local method. Moreover it does not regularize the results found. It proposes several matching costs, such as the Zero mean Normalised Cross-Correlation or statistical measures (the Mutual Information being one of them), and different match validation flags. QPEC / Medicis is able to compute a two-dimensional dense disparity map with a subpixel precision. Hence, it is more versatile than disparity estimation methods found in computer vision literature, which often assume an epipolar geometry. CNES uses Medicis, among other applications, during the in-orbit image quality commissioning of earth observation satellites. For instance the Pléiades-HR 1A & 1B and the Sentinel-2 geometric calibrations are based on this block matching algorithm. Over the years, it has become a common tool in ground segments for in-flight monitoring purposes. For these two kinds of applications, the two-dimensional search and the local sub-pixel measure without regularization can be essential. This tool is also used to generate automatic digital elevation models, for which it was not initially dedicated. This paper deals with the QPEC / Medicis algorithm. It also presents some of its CNES applications (in-orbit commissioning, in flight monitoring or digital elevation model generation). Medicis software is distributed outside the CNES as well. This paper finally describes some of these external applications using Medicis, such as ground displacement measurement, or intra-oral scanner in the dental domain.

  3. Urban Image Classification: Per-Pixel Classifiers, Sub-Pixel Analysis, Object-Based Image Analysis, and Geospatial Methods. 10; Chapter

    NASA Technical Reports Server (NTRS)

    Myint, Soe W.; Mesev, Victor; Quattrochi, Dale; Wentz, Elizabeth A.

    2013-01-01

    Remote sensing methods used to generate base maps to analyze the urban environment rely predominantly on digital sensor data from space-borne platforms. This is due in part from new sources of high spatial resolution data covering the globe, a variety of multispectral and multitemporal sources, sophisticated statistical and geospatial methods, and compatibility with GIS data sources and methods. The goal of this chapter is to review the four groups of classification methods for digital sensor data from space-borne platforms; per-pixel, sub-pixel, object-based (spatial-based), and geospatial methods. Per-pixel methods are widely used methods that classify pixels into distinct categories based solely on the spectral and ancillary information within that pixel. They are used for simple calculations of environmental indices (e.g., NDVI) to sophisticated expert systems to assign urban land covers. Researchers recognize however, that even with the smallest pixel size the spectral information within a pixel is really a combination of multiple urban surfaces. Sub-pixel classification methods therefore aim to statistically quantify the mixture of surfaces to improve overall classification accuracy. While within pixel variations exist, there is also significant evidence that groups of nearby pixels have similar spectral information and therefore belong to the same classification category. Object-oriented methods have emerged that group pixels prior to classification based on spectral similarity and spatial proximity. Classification accuracy using object-based methods show significant success and promise for numerous urban 3 applications. Like the object-oriented methods that recognize the importance of spatial proximity, geospatial methods for urban mapping also utilize neighboring pixels in the classification process. The primary difference though is that geostatistical methods (e.g., spatial autocorrelation methods) are utilized during both the pre- and post

  4. Method of anti-aliasing with the use of the new pixel model

    NASA Astrophysics Data System (ADS)

    Romanyuk, Olexander N.; Pavlov, Sergii V.; Melnyk, Olexander V.; Romanyuk, Sergii O.; Smolarz, Andrzej; Bazarova, Madina

    2015-12-01

    The paper proposes additional evaluation functions to mark the segment area that cuts straight line to determine the intensity of the color pixel. For anti-aliasing purposes a twelve-angle pixel model is suggested. Additional evaluation functions are used to identify the pixel color intensity. These functions can be calculated independently. A structure of a device is proposed for hardware implementation of anti-aliasing.

  5. IV and CV curves for irradiated prototype BTeV silicon pixel sensors

    SciTech Connect

    Maria R. Coluccia et al.

    2002-07-16

    The authors present IV and CV curves for irradiated prototype n{sup +}/n/p{sup +} silicon pixel sensors, intended for use in the BTeV experiment at Fermilab. They tested pixel sensors from various vendors and with two pixel isolation layouts: p-stop and p-spray. Results are based on exposure with 200 MeV protons up to 6 x 10{sup 14} protons/cm{sup 2}.

  6. 1T Pixel Using Floating-Body MOSFET for CMOS Image Sensors

    PubMed Central

    Lu, Guo-Neng; Tournier, Arnaud; Roy, François; Deschamps, Benoît

    2009-01-01

    We present a single-transistor pixel for CMOS image sensors (CIS). It is a floating-body MOSFET structure, which is used as photo-sensing device and source-follower transistor, and can be controlled to store and evacuate charges. Our investigation into this 1T pixel structure includes modeling to obtain analytical description of conversion gain. Model validation has been done by comparing theoretical predictions and experimental results. On the other hand, the 1T pixel structure has been implemented in different configurations, including rectangular-gate and ring-gate designs, and variations of oxidation parameters for the fabrication process. The pixel characteristics are presented and discussed. PMID:22389592

  7. Characterization of Pixelated Cadmium-Zinc-Telluride Detectors for Astrophysical Applications

    NASA Technical Reports Server (NTRS)

    Gaskin, Jessica; Sharma, Dharma; Ramsey, Brian; Seller, Paul

    2003-01-01

    Comparisons of charge sharing and charge loss measurements between two pixelated Cadmium-Zinc-Telluride (CdZnTe) detectors are discussed. These properties along with the detector geometry help to define the limiting energy resolution and spatial resolution of the detector in question. The first detector consists of a 1-mm-thick piece of CdZnTe sputtered with a 4x4 array of pixels with pixel pitch of 750 microns (inter-pixel gap is 100 microns). Signal readout is via discrete ultra-low-noise preamplifiers, one for each of the 16 pixels. The second detector consists of a 2-mm-thick piece of CdZnTe sputtered with a 16x16 array of pixels with a pixel pitch of 300 microns (inter-pixel gap is 50 microns). This crystal is bonded to a custom-built readout chip (ASIC) providing all front-end electronics to each of the 256 independent pixels. These detectors act as precursors to that which will be used at the focal plane of the High Energy Replicated Optics (HERO) telescope currently being developed at Marshall Space Flight Center. With a telescope focal length of 6 meters, the detector needs to have a spatial resolution of around 200 microns in order to take full advantage of the HERO angular resolution. We discuss to what degree charge sharing will degrade energy resolution but will improve our spatial resolution through position interpolation.

  8. Increased space-bandwidth product in pixel super-resolved lensfree on-chip microscopy

    PubMed Central

    Greenbaum, Alon; Luo, Wei; Khademhosseinieh, Bahar; Su, Ting-Wei; Coskun, Ahmet F.; Ozcan, Aydogan

    2013-01-01

    Pixel-size limitation of lensfree on-chip microscopy can be circumvented by utilizing pixel-super-resolution techniques to synthesize a smaller effective pixel, improving the resolution. Here we report that by using the two-dimensional pixel-function of an image sensor-array as an input to lensfree image reconstruction, pixel-super-resolution can improve the numerical aperture of the reconstructed image by ~3 fold compared to a raw lensfree image. This improvement was confirmed using two different sensor-arrays that significantly vary in their pixel-sizes, circuit architectures and digital/optical readout mechanisms, empirically pointing to roughly the same space-bandwidth improvement factor regardless of the sensor-array employed in our set-up. Furthermore, such a pixel-count increase also renders our on-chip microscope into a Giga-pixel imager, where an effective pixel count of ~1.6–2.5 billion can be obtained with different sensors. Finally, using an ultra-violet light-emitting-diode, this platform resolves 225 nm grating lines and can be useful for wide-field on-chip imaging of nano-scale objects, e.g., multi-walled-carbon-nanotubes.

  9. Enhanced correction methods for high density hot pixel defects in digital imagers

    NASA Astrophysics Data System (ADS)

    Chapman, Glenn H.; Thomas, Rahul; Thomas, Rohit; Koren, Zahava; Koren, Israel

    2015-03-01

    Our previous research has found that the main defects in digital cameras are "Hot Pixels" which increase at a nearly constant temporal rate. Defect rates have been shown to grow as a power law of the pixel size and ISO, potentially causing hundreds to thousands of defects per year in cameras with <2 micron pixels, thus making image correction crucial. This paper discusses a novel correction method that uses a weighted combination of two terms - traditional interpolation and hot pixel parameters correction. The weights are based on defect severity, ISO, exposure time and complexity of the image. For the hot pixel parameters component, we have studied the behavior of hot pixels under illumination and have created a new correction model that takes this behavior into account. We show that for an image with a slowly changing background, the classic interpolation performs well. However, for more complex scenes, the correction improves when a weighted combination of both components is used. To test our algorithm's accuracy, we devised a novel laboratory experimental method for extracting the true value of the pixel that currently experiences a hot pixel defect. This method involves a simple translation of the imager based on the pixel size and other optical distances.

  10. Fast Contour-Tracing Algorithm Based on a Pixel-Following Method for Image Sensors.

    PubMed

    Seo, Jonghoon; Chae, Seungho; Shim, Jinwook; Kim, Dongchul; Cheong, Cheolho; Han, Tack-Don

    2016-03-09

    Contour pixels distinguish objects from the background. Tracing and extracting contour pixels are widely used for smart/wearable image sensor devices, because these are simple and useful for detecting objects. In this paper, we present a novel contour-tracing algorithm for fast and accurate contour following. The proposed algorithm classifies the type of contour pixel, based on its local pattern. Then, it traces the next contour using the previous pixel's type. Therefore, it can classify the type of contour pixels as a straight line, inner corner, outer corner and inner-outer corner, and it can extract pixels of a specific contour type. Moreover, it can trace contour pixels rapidly because it can determine the local minimal path using the contour case. In addition, the proposed algorithm is capable of the compressing data of contour pixels using the representative points and inner-outer corner points, and it can accurately restore the contour image from the data. To compare the performance of the proposed algorithm to that of conventional techniques, we measure their processing time and accuracy. In the experimental results, the proposed algorithm shows better performance compared to the others. Furthermore, it can provide the compressed data of contour pixels and restore them accurately, including the inner-outer corner, which cannot be restored using conventional algorithms.

  11. Reducing the effect of pixel crosstalk in phase only spatial light modulators.

    PubMed

    Persson, Martin; Engström, David; Goksör, Mattias

    2012-09-24

    A method for compensating for pixel crosstalk in liquid crystal based spatial light modulators is presented. By modifying a commonly used hologram generating algorithm to account for pixel crosstalk, the intensity errors in obtained diffraction spot intensities are significantly reduced. We also introduce a novel method for characterizing the pixel crosstalk in phase-only spatial light modulators, providing input for the hologram generating algorithm. The methods are experimentally evaluated and an improvement of the spot uniformity by more than 100% is demonstrated for an SLM with large pixel crosstalk. PMID:23037382

  12. Electronic holographic device based on macro-pixel with local coherence

    NASA Astrophysics Data System (ADS)

    Moon, Woonchan; Kwon, Jaebeom; Kim, Hwi; Hahn, Joonku

    2015-09-01

    Holography has been regarded as one of the most ideal technique for three-dimensional (3D) display because it records and reconstructs both amplitude and phase of object wave simultaneously. Nevertheless, many people think that this technique is not suitable for commercialization due to some significant problems. In this paper, we propose an electronic holographic 3D display based on macro-pixel with local coherence. Here, the incident wave within each macro-pixel is coherent but the wave in one macro-pixel is not mutually coherent with the wave in the other macro-pixel. This concept provides amazing freedom in distribution of the pixels in modulator. The relative distance between two macro-pixels results in negligible change of interference pattern in observation space. Also it is possible to make the sub-pixels in a macro-pixel in order to enlarge the field of view (FOV). The idea has amazing effects to reduce the data capacity of the holographic display. Moreover, the dimension of the system is can be remarkably downsized by micro-optics. As a result, the holographic display will be designed to have full parallax with large FOV and screen size. We think that the macro-pixel idea is a practical solution in electronic holography since it can provide reasonable FOV and large screen size with relatively small amount of data.

  13. Shape determination of microcalcifications in simulated digital mammography images with varying pixel size

    NASA Astrophysics Data System (ADS)

    Ruschin, Mark; Bath, Magnus; Hemdal, Bengt; Tingberg, Anders

    2005-04-01

    The purpose of this work was to study how the pixel size of digital detectors can affect shape determination of microcalcifications in mammography. Screen-film mammograms containing microcalcifications clinically proven to be indicative of malignancy were digitised at 100 lines/mm using a high-resolution Tango drum scanner. Forty microcalcifications were selected to cover an appropriate range of sizes, shapes and contrasts typically found of malignant cases. Based on the measured MTF and NPS of the combined screen-film and scanner system, these digitised images were filtered to simulate images acquired with a square sampling pixel size of 10 μm x 10 μm and a fill factor of one. To simulate images acquired with larger pixel sizes, these finely sampled images were re-binned to yield a range of effective pixel sizes from 20 μm up to 140 μm. An alternative forced-choice (AFC) observer experiment was conducted with eleven observers for this set of digitised microcalcifications to determine how pixel size affects the ability to discriminate shape. It was found that observer score increased with decreasing pixel size down to 60 μm (p<0.01), at which point no significant advantage was obtained by using smaller pixel sizes due to the excessive relative noise-per-pixel. The relative gain in shape discrimination ability at smaller pixel sizes was larger for microcalcifications that were smaller than 500 μm and circular.

  14. Error analysis of filtering operations in pixel-duplicated images of diabetic retinopathy

    NASA Astrophysics Data System (ADS)

    Mehrubeoglu, Mehrube; McLauchlan, Lifford

    2010-08-01

    In this paper, diabetic retinopathy is chosen for a sample target image to demonstrate the effectiveness of image enlargement through pixel duplication in identifying regions of interest. Pixel duplication is presented as a simpler alternative to data interpolation techniques for detecting small structures in the images. A comparative analysis is performed on different image processing schemes applied to both original and pixel-duplicated images. Structures of interest are detected and and classification parameters optimized for minimum false positive detection in the original and enlarged retinal pictures. The error analysis demonstrates the advantages as well as shortcomings of pixel duplication in image enhancement when spatial averaging operations (smoothing filters) are also applied.

  15. Fast Contour-Tracing Algorithm Based on a Pixel-Following Method for Image Sensors.

    PubMed

    Seo, Jonghoon; Chae, Seungho; Shim, Jinwook; Kim, Dongchul; Cheong, Cheolho; Han, Tack-Don

    2016-01-01

    Contour pixels distinguish objects from the background. Tracing and extracting contour pixels are widely used for smart/wearable image sensor devices, because these are simple and useful for detecting objects. In this paper, we present a novel contour-tracing algorithm for fast and accurate contour following. The proposed algorithm classifies the type of contour pixel, based on its local pattern. Then, it traces the next contour using the previous pixel's type. Therefore, it can classify the type of contour pixels as a straight line, inner corner, outer corner and inner-outer corner, and it can extract pixels of a specific contour type. Moreover, it can trace contour pixels rapidly because it can determine the local minimal path using the contour case. In addition, the proposed algorithm is capable of the compressing data of contour pixels using the representative points and inner-outer corner points, and it can accurately restore the contour image from the data. To compare the performance of the proposed algorithm to that of conventional techniques, we measure their processing time and accuracy. In the experimental results, the proposed algorithm shows better performance compared to the others. Furthermore, it can provide the compressed data of contour pixels and restore them accurately, including the inner-outer corner, which cannot be restored using conventional algorithms. PMID:27005632

  16. Design of a 3D-IC multi-resolution digital pixel sensor

    NASA Astrophysics Data System (ADS)

    Brochard, N.; Nebhen, J.; Dubois, J.; Ginhac, D.

    2016-04-01

    This paper presents a digital pixel sensor (DPS) integrating a sigma-delta analog-to-digital converter (ADC) at pixel level. The digital pixel includes a photodiode, a delta-sigma modulation and a digital decimation filter. It features adaptive dynamic range and multiple resolutions (up to 10-bit) with a high linearity. A specific row decoder and column decoder are also designed to permit to read a specific pixel chosen in the matrix and its neighborhood of 4 x 4. Finally, a complete design with the CMOS 130 nm 3D-IC FaStack Tezzaron technology is also described, revealing a high fill-factor of about 80%.

  17. Supervised pixel classification using a feature space derived from an artificial visual system

    NASA Astrophysics Data System (ADS)

    Baxter, Lisa C.; Coggins, James M.

    1991-06-01

    Image segmentation involves labelling pixels according to their membership in image regions. This requires the understanding of what a region is. Using supervised pixel classification, the paper investigates how groups of pixels labelled manually according to perceived image semantics map onto the feature space created by an Artificial Visual System. Multiscale structure of regions are investigated and it is shown that pixels form clusters based on their geometric roles in the image intensity function, not by image semantics. A tentative abstract definition of a 'region' is proposed based on this behavior.

  18. Compact all-CMOS spatiotemporal compressive sensing video camera with pixel-wise coded exposure.

    PubMed

    Zhang, Jie; Xiong, Tao; Tran, Trac; Chin, Sang; Etienne-Cummings, Ralph

    2016-04-18

    We present a low power all-CMOS implementation of temporal compressive sensing with pixel-wise coded exposure. This image sensor can increase video pixel resolution and frame rate simultaneously while reducing data readout speed. Compared to previous architectures, this system modulates pixel exposure at the individual photo-diode electronically without external optical components. Thus, the system provides reduction in size and power compare to previous optics based implementations. The prototype image sensor (127 × 90 pixels) can reconstruct 100 fps videos from coded images sampled at 5 fps. With 20× reduction in readout speed, our CMOS image sensor only consumes 14μW to provide 100 fps videos.

  19. Indium gallium arsenide imaging with smaller cameras, higher-resolution arrays, and greater material sensitivity

    NASA Astrophysics Data System (ADS)

    Ettenberg, Martin H.; Cohen, Marshall J.; Brubaker, Robert M.; Lange, Michael J.; O'Grady, Matthew T.; Olsen, Gregory H.

    2002-08-01

    Indium Gallium Arsenide (InGaAs) photodiode arrays have numerous commercial, industrial, and military applications. During the past 10 years, great strides have been made in the development of these devices starting with simple 256-element linear photodiode arrays and progressing to the large 640 x 512 element area arrays now readily available. Linear arrays are offered with 512 elements on a 25 micron pitch with no defective pixels, and are used in spectroscopic monitors for wavelength division multiplexing (WDM) systems as well as in machine vision applications. A 320 x 240 solid-state array operates at room temperature, which allows development of a camera which is smaller than 25 cm3 in volume, weighs less than 100 g and uses less than 750 mW of power. Two dimensional focal plane arrays and cameras have been manufactured with detectivity, D*, greater than 1014 cm-(root)Hz/W at room temperature and have demonstrated the ability to image at night. Cameras are also critical tools for the assembly and performance monitoring of optical switches and add-drop multiplexers in the telecommunications industry. These same cameras are used for the inspection of silicon wafers and fine art, laser beam profiling, and metals manufacturing. By varying the Indium content, InGaAs photodiode arrays can be tailored to cover the entire short-wave infrared spectrum from 1.0 micron to 2.5 microns. InGaAs focal plane arrays and cameras sensitive to 2.0 micron wavelength light are now available in 320 x 240 formats.

  20. First Light with a 67-Million-Pixel WFI Camera

    NASA Astrophysics Data System (ADS)

    1999-01-01

    The newest astronomical instrument at the La Silla observatory is a super-camera with no less than sixty-seven million image elements. It represents the outcome of a joint project between the European Southern Observatory (ESO) , the Max-Planck-Institut für Astronomie (MPI-A) in Heidelberg (Germany) and the Osservatorio Astronomico di Capodimonte (OAC) near Naples (Italy), and was installed at the 2.2-m MPG/ESO telescope in December 1998. Following careful adjustment and testing, it has now produced the first spectacular test images. With a field size larger than the Full Moon, the new digital Wide Field Imager is able to obtain detailed views of extended celestial objects to very faint magnitudes. It is the first of a new generation of survey facilities at ESO with which a variety of large-scale searches will soon be made over extended regions of the southern sky. These programmes will lead to the discovery of particularly interesting and unusual (rare) celestial objects that may then be studied with large telescopes like the VLT at Paranal. This will in turn allow astronomers to penetrate deeper and deeper into the many secrets of the Universe. More light + larger fields = more information! The larger a telescope is, the more light - and hence information about the Universe and its constituents - it can collect. This simple truth represents the main reason for building ESO's Very Large Telescope (VLT) at the Paranal Observatory. However, the information-gathering power of astronomical equipment can also be increased by using a larger detector with more image elements (pixels) , thus permitting the simultaneous recording of images of larger sky fields (or more details in the same field). It is for similar reasons that many professional photographers prefer larger-format cameras and/or wide-angle lenses to the more conventional ones. The Wide Field Imager at the 2.2-m telescope Because of technological limitations, the sizes of detectors most commonly in use in

  1. a Comparison of Sub-Pixel Mapping Methods for Coastal Areas

    NASA Astrophysics Data System (ADS)

    Liu, Qingxiang; Trinder, John; Turner, Ian

    2016-06-01

    This paper presents the comparisons of three soft classification methods and three sub-pixel mapping methods for the classification of coastal areas at sub-pixel level. Specifically, SPOT-7 multispectral images covering the coastal area of Perth are selected as the experiment dataset. For the soft classification, linear spectral unmixing model, supervised fully-fuzzy classification method and the support vector machine are applied to generate the fraction map. Then for the sub-pixel mapping, the sub-pixel/pixel attraction model, pixel swapping and wavelets method are compared. Besides, the influence of the correct fraction constraint is explored. Moreover, a post-processing step is implemented according to the known spatial knowledge of coastal areas. The accuracy assessment of the fraction values indicates that support vector machine generates the most accurate fraction result. For sub-pixel mapping, wavelets method outperforms the other two methods with overall classification accuracy of 91.79% and Kappa coefficient of 0.875 after the post-processing step and it also performs best for waterline extraction with mean distance of 0.71m to the reference waterline. In this experiment, the use of correct fraction constraint decreases the classification accuracy of sub-pixel mapping methods and waterline extraction. Finally, the post-processing step improves the accuracy of sub-pixel mapping methods, especially for those with correct coefficient constraint. The most significant improvement of overall accuracy is as much as 4% for the sub-pixel/pixel attraction model with correct coefficient constraint.

  2. Signal and noise of diamond pixel detectors at high radiation fluences

    NASA Astrophysics Data System (ADS)

    Tsung, J.-W.; Havranek, M.; Hügging, F.; Kagan, H.; Krüger, H.; Wermes, N.

    2012-09-01

    CVD diamond is an attractive material option for LHC vertex detectors mainly because of its strong radiation-hardness causal to its large band gap and strong lattice. In particular, pixel detectors operating close to the interaction point profit from tiny leakage currents and small pixel capacitances of diamond resulting in low noise figures when compared to silicon. On the other hand, the charge signal from traversing high energy particles is smaller in diamond than in silicon by a factor of about 2.2. Therefore, a quantitative determination of the signal-to-noise ratio (S/N) of diamond in comparison with silicon at fluences in excess of 1015 neq cm-2, which are expected for the LHC upgrade, is important. Based on measurements of irradiated diamond sensors and the FE-I4 pixel readout chip design and performance, we determine the signal and the noise of diamond pixel detectors irradiated with high particle fluences. To characterize the effect of the radiation damage on the materials and the signal decrease, the change of the mean free path λe/h of the charge carriers is determined as a function of irradiation fluence. We make use of the FE-I4 pixel chip developed for ATLAS upgrades to realistically estimate the expected noise figures: the expected leakage current at a given fluence is taken from calibrated calculations and the pixel capacitance is measured using a purposely developed chip (PixCap). We compare the resulting S/N figures with those for planar silicon pixel detectors using published charge loss measurements and the same extrapolation methods as for diamond. It is shown that the expected S/N of a diamond pixel detector with pixel pitches typical for LHC, exceeds that of planar silicon pixels at fluences beyond 1015 particles cm-2, the exact value only depending on the maximum operation voltage assumed for irradiated silicon pixel detectors.

  3. Adhesive Testing for the BTeV Pixel Detector

    SciTech Connect

    Lei, C.M.; Kwan, Simon; Hicks, D.; Hahn, Eileen; Hoffman, Jay; Austin, Sharon; Jones, Renee; /Fermilab

    2005-12-01

    The basic unit of the BTeV pixel detector is a multi-chip module which is comprised of a silicon sensor module bump-bonded to a number of readout chips. The pixel module will then be glued to a high intensity interconnect (HDI) cable using electrically conductive adhesive, and then onto a substrate using another kind of adhesive with reasonable thermal conductivity. This report is mostly addressed to the need of the latter--the substrate adhesive. The aim of this technical note is to summarize the testing efforts and results of this substrate adhesive covering a period since 2001 till the end of 2004. The substrate will serve two purposes: mechanical support and cooling of the modules. Stresses and strains will be generated when there is a thermal change on the substrate. In addition, since there are many kinds of materials, with different coefficient of thermal expansion (CTE), being glued together to form the complete detector assembly, the substrate may get distorted due to the CTE mismatches. As stress is directly proportional to the material modulus, a significant amount of effort was concentrated in understanding the adhesive modulus. There are other constraints which need to be considered as well. For instance, the detector will be placed in a vacuum close to the beam, and it will be exposed to significant radiation during operation. As there are so many requirements on the adhesive, it is certainly not that easy to find one that meets all the demands. With a reasonable screening that the adhesive candidates being radiation hard and have low outgassing, searching for suitable adhesives was focused on those with low modulus. That is because (1) a mechanically reliable and fail-proof adhesive structure with low stress is needed, and (2) the leaking current characteristics of the modules will increase if mechanical stresses are too high. However, much of the technical information needed is usually not available from the vendor and therefore testing on our own

  4. EDITORIAL: Micro-pixellated LEDs for science and instrumentation

    NASA Astrophysics Data System (ADS)

    Dawson, Martin D.; Neil, Mark A. A.

    2008-05-01

    This Cluster Issue of Journal of Physics D: Applied Physics highlights micro-pixellated gallium nitride light-emitting diodes or `micro-LEDs', an emerging technology offering considerable attractions for a broad range of scientific and instrumentation applications. It showcases the results of a Research Councils UK (RCUK) Basic Technology Research programme (http://bt-onethousand.photonics.ac.uk), running from 2004-2008, which has drawn together a multi-disciplinary and multi-institutional research partnership to develop these devices and explore their potential. Images of LEDs Examples of GaN micro-pixel LEDs in operation. Images supplied courtesy of the Guest Editors. The partnership, of physicists, engineers and chemists drawn from the University of Strathclyde, Heriot-Watt University, the University of Sheffield and Imperial College London, has sought to move beyond the established mass-market uses of gallium nitride LEDs in illumination and lighting. Instead, it focuses on specialised solid-state micro-projection devices the size of a match-head, containing up to several thousand individually-addressable micro-pixel elements emitting light in the ultraviolet or visible regions of the spectrum. Such sources are pattern-programmable under computer control and can project into materials fixed or high-frame rate optical images or spatially-controllable patterns of nanosecond excitation pulses. These materials can be as diverse as biological cells and tissues, biopolymers, photoresists and organic semiconductors, leading to new developments in optical microscopy, bio-sensing and chemical sensing, mask-free lithography and direct writing, and organic electronics. Particular areas of interest are multi-modal microscopy, integrated forms of organic semiconductor lasers, lab-on-a-chip, GaN/Si optoelectronics and hybrid inorganic/organic semiconductor structures. This Cluster Issue contains four invited papers and ten contributed papers. The invited papers serve to set

  5. Optimization of convergent collimators for pixelated SPECT systems

    SciTech Connect

    Capote, Ricardo M.; Matela, Nuno; Conceicao, Raquel C.; Almeida, Pedro

    2013-06-15

    Purpose: The optimization of the collimator design is essential to obtain the best possible sensitivity in single photon emission computed tomography imaging. The aim of this work is to present a methodology for maximizing the sensitivity of convergent collimators, specifically designed to match the pitch of pixelated detectors, for a fixed spatial resolution value and to present some initial results using this approach. Methods: Given the matched constraint, the optimal collimator design cannot be simply found by allowing the highest level of septal penetration and spatial resolution consistent with the imposed restrictions, as it is done for the optimization of conventional collimators. Therefore, an algorithm that interactively calculates the collimator dimensions, with the maximum sensitivity, which respect the imposed restrictions was developed and used to optimize cone and fan beam collimators with tapered square-shaped holes for low (60-300 keV) and high energy radiation (300-511 keV). The optimal collimator dimensions were locally calculated based on the premise that each hole and septa of the convergent collimator should locally resemble an appropriate optimal matched parallel collimator. Results: The optimal collimator dimensions, calculated for subcentimeter resolutions (3 and 7.5 mm), common pixel sizes (1.6, 2.1, and 2.5 mm), and acceptable septal penetration at 140 keV, were approximately constant throughout the collimator, despite their different hole incidence angles. By using these input parameters and a less strict septal penetration value of 5%, the optimal collimator dimensions and the corresponding mass per detector area were calculated for 511 keV. It is shown that a low value of focal distance leads to improvements in the average sensitivity at a fixed source-collimator distance and resolution. The optimal cone beam performance outperformed that of other optimal collimation geometries (fan and parallel beam) in imaging objects close to the

  6. Development and characterization of the latest X-ray SOI pixel sensor for a future astronomical mission

    NASA Astrophysics Data System (ADS)

    Nakashima, Shinya; Gando Ryu, Syukyo; Tanaka, Takaaki; Go Tsuru, Takeshi; Takeda, Ayaki; Arai, Yasuo; Imamura, Toshifumi; Ohmoto, Takafumi; Iwata, Atsushi

    2013-12-01

    We have been developing active pixel sensors based on silicon-on-insulator technology for future X-ray astronomy missions. Recently we fabricated the new prototype named “XRPIX2”, and investigated its spectroscopic performance. For comparison and evaluation of different chip designs, XRPIX2 consists of 3 pixel types: Small Pixel, Large Pixel 1, and Large Pixel 2. In Small Pixel, we found that the gains of the 68% pixels are within 1.4% of the mean value, and the energy resolution is 656 eV (FWHM) for 8 keV X-rays, which is the best spectroscopic performance in our development. The pixel pitch of Large Pixel 1 and Large Pixel 2 is twice as large as that of Small Pixel. Charge sharing events are successfully reduced for Large Pixel 1. Moreover Large Pixel 2 has multiple nodes for charge collection in a pixel. We confirmed that the multi-nodes structure is effective to increase charge collection efficiency.

  7. Comparison of Sub-Pixel Classification Approaches for Crop-Specific Mapping

    EPA Science Inventory

    This paper examined two non-linear models, Multilayer Perceptron (MLP) regression and Regression Tree (RT), for estimating sub-pixel crop proportions using time-series MODIS-NDVI data. The sub-pixel proportions were estimated for three major crop types including corn, soybean, a...

  8. Controlled pixelation of inverse opaline structures towards reflection-mode displays.

    PubMed

    Lee, Su Yeon; Kim, Shin-Hyun; Hwang, Hyerim; Sim, Jae Young; Yang, Seung-Man

    2014-04-16

    Pixelated inverse opals with red, green, and blue colors were prepared by hybridizing convective assembly of colloidal particles and photolithography techniques. The brilliant structural colors, high mechanical stability, and small feature size of the pixels were simultaneously accomplished, thereby providing color reflectors potentially useful for display devices. Moreover, this hybridized method provides a general means to create multi-colored photonic crystals. PMID:24458607

  9. Beam test results for the BTeV silicon pixel detector

    SciTech Connect

    Jeffrey A. Appel, G. Chiodini et al.

    2000-09-28

    The authors report the results of the BTeV silicon pixel detector tests carried out in the MTest beam at Fermilab in 1999--2000. The pixel detector spatial resolution has been studied as a function of track inclination, sensor bias, and readout threshold.

  10. Simulation on the Charged Particle Response of the STAR Heavy Flavor Tracker Pixel Detector

    NASA Astrophysics Data System (ADS)

    Cimaroli, Alex; Li, Xin

    2009-10-01

    The main task of the STAR experiment, located at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, is to study the quark-gluon plasma (QGP), which is believed to have been created a few microseconds after the ``Big Bang.'' Heavy quarks are ideal tools for studying the properties of QGP. The Heavy Flavor Tracker (HFT) is the central part of the STAR future heavy flavor physics program and will enable STAR to directly measure heavy flavor mesons. The core of HFT is a pixel detector (PIXEL) using CMOS Active PIXEL Sensor. This poster will describe the development of a detailed simulation of the pixel detector response to charged particles and the corresponding fast simulation that dramatically enhances the simulation speed with little sacrifice in accuracy. The full simulation randomly generates ionized electrons along an incoming track and diffuses the electrons inside the pixel array until they are collected by the electronics or recombined inside a pixel. With the same result, the fast simulation, which quickens processing time from one hour to 5 seconds, generates a grid inside a single pixel and create a map of probability distribution functions for a single ionized electron generated from a grid point. We will also discuss the study of pixel detector position resolution using a simple clustering algorithm.

  11. Modulation efficiency of double-phase hologram complex light modulation macro-pixels.

    PubMed

    Choi, Sujin; Roh, Jinyoung; Song, Hoong; Sung, Geeyoung; An, Jungkwuen; Seo, Wontaek; Won, Kanghee; Ungnapatanin, Jesada; Jung, Myounghoon; Yoon, Yongzoon; Lee, Hong-Seok; Oh, Chang-Hyun; Hahn, Joonku; Kim, Hwi

    2014-09-01

    The modulation efficiency of the double-phase hologram macro-pixel that is designed for complex modulation of light waves is defined and analyzed. The scale-down of the double-phase hologram macro-pixel associated with the construction of complex spatial light modulators is discussed.

  12. DISPLAY OF PIXEL LOSS AND REPLICATION IN REPROJECTING RASTER DATA FROM THE SINUSOIDAL PROJECTION

    EPA Science Inventory

    Recent studies show the sinusoidal projection to be a superior planar projection for representing global raster datasets. This study uses the sinusoidal projection as a basis for evaluating pixel loss and replication in eight other planar map projections. The percent of pixels ...

  13. Fast Contour-Tracing Algorithm Based on a Pixel-Following Method for Image Sensors

    PubMed Central

    Seo, Jonghoon; Chae, Seungho; Shim, Jinwook; Kim, Dongchul; Cheong, Cheolho; Han, Tack-Don

    2016-01-01

    Contour pixels distinguish objects from the background. Tracing and extracting contour pixels are widely used for smart/wearable image sensor devices, because these are simple and useful for detecting objects. In this paper, we present a novel contour-tracing algorithm for fast and accurate contour following. The proposed algorithm classifies the type of contour pixel, based on its local pattern. Then, it traces the next contour using the previous pixel’s type. Therefore, it can classify the type of contour pixels as a straight line, inner corner, outer corner and inner-outer corner, and it can extract pixels of a specific contour type. Moreover, it can trace contour pixels rapidly because it can determine the local minimal path using the contour case. In addition, the proposed algorithm is capable of the compressing data of contour pixels using the representative points and inner-outer corner points, and it can accurately restore the contour image from the data. To compare the performance of the proposed algorithm to that of conventional techniques, we measure their processing time and accuracy. In the experimental results, the proposed algorithm shows better performance compared to the others. Furthermore, it can provide the compressed data of contour pixels and restore them accurately, including the inner-outer corner, which cannot be restored using conventional algorithms. PMID:27005632

  14. Compensation for radiation damage of SOI pixel detector via tunneling

    NASA Astrophysics Data System (ADS)

    Yamada, M.; Arai, Y.; Fujita, Y.; Hamasaki, R.; Ikegami, Y.; Kurachi, I.; Miyoshi, T.; Nishimura, R.; Tauchi, K.; Tsuboyama, T.

    2016-09-01

    We are developing a method for removing holes trapped in the oxide layer of a silicon-on-insulator (SOI) monolithic pixel detector after irradiation. Radiation that passes through the detector generates positive charge by trapped holes in the buried oxide layer (BOX) underneath the MOSFET. The positive potential caused by these trapped holes modifies the characteristics of the MOSFET of the signal readout circuit. In order to compensate for the effect of the positive potential, we tried to recombine the trapped holes with electrons via Fowler-Nordheim (FN) tunneling. By applying high voltage to the buried p-well (BPW) under the oxide layer with the MOSFET fixed at 0 V, electrons are injected into the BOX by FN tunneling. X-rays cause a negative shift in the threshold voltage Vth of the MOSFET. We can successfully recover Vth close to its pre-irradiation level after applying VBPW ≥ 120 V. However, the drain leakage current increased after applying VBPW; we find that this can be suppressed by applying a negative voltage to the BPW.

  15. Ultrahigh-temperature emitter pixel development for scene projectors

    NASA Astrophysics Data System (ADS)

    Sparkman, Kevin; LaVeigne, Joe; McHugh, Steve; Lannon, John; Goodwin, Scott

    2014-05-01

    To meet the needs of high fidelity infrared sensors, under the Ultra High Temperature (UHT) development program, Santa Barbara Infrared Inc. (SBIR) has developed new infrared emitter materials capable of achieving extremely high temperatures. The current state of the art arrays based on the MIRAGE-XL generation of scene projectors is capable of producing imagery with mid-wave infrared (MWIR) apparent temperatures up to 700K with response times of 5 ms. The Test Resource Management Center (TRMC) Test and Evaluation/Science and Technology (TandE/SandT) Program through the U.S. Army Program Executive Office for Simulation, Training and Instrumentations (PEO STRI) has contracted with SBIR and its partners to develop a new resistive array based on these new materials, using a high current Read-In Integrated Circuit (RIIC) capable of achieving higher temperatures as well as faster frame rates. The status of that development will be detailed within this paper, including performance data from prototype pixels.

  16. Preliminary study for pixel identification on a modular gamma camera

    NASA Astrophysics Data System (ADS)

    Soluri, A.; Atzeni, G.; Ucci, A.; Cusanno, F.; Massari, R.

    2014-02-01

    Our group has recently investigated and produced new scintigraphic prototypes based on advanced scintillation structure. The aim of this study is to demonstrate the use of scintillation matrices with size equal to the overall area of the Position Sensitive Photomultiplier Tube (PSPMT), to design a modular gamma camera and study the solution of the dead area problems optimizing the overall pixel identification. In this paper we investigate the response of different combinations with crystals integrated within tungsten structure, coupled with H8500, R8900-C12 and R11265-M64 Hamamatsu PSPMTs. Several scintillation matrices, whose dimensions match to the physical area of the PSPMT, have been analysed so that we have also studied limits of detection for the elements of the matrix in the critical zones of the PSPMT, i.e. corners and borders. In order to enhance the detectability of scintillation elements we improved the light collection by depositing metallic layers or treating the tungsten structure with different coating materials, and shaping the external elements of the scintillation matrices. The results have shown good energy resolution and the proposed method can be applied in medical imaging for obtaining high efficiency scintillation devices.

  17. EVEREST: Pixel Level Decorrelation of K2 Light Curves

    NASA Astrophysics Data System (ADS)

    Luger, Rodrigo; Agol, Eric; Kruse, Ethan; Barnes, Rory; Becker, Andrew; Foreman-Mackey, Daniel; Deming, Drake

    2016-10-01

    We present EPIC Variability Extraction and Removal for Exoplanet Science Targets (EVEREST), an open-source pipeline for removing instrumental noise from K2 light curves. EVEREST employs a variant of pixel level decorrelation to remove systematics introduced by the spacecraft’s pointing error and a Gaussian process to capture astrophysical variability. We apply EVEREST to all K2 targets in campaigns 0–7, yielding light curves with precision comparable to that of the original Kepler mission for stars brighter than {K}p≈ 13, and within a factor of two of the Kepler precision for fainter targets. We perform cross-validation and transit injection and recovery tests to validate the pipeline, and compare our light curves to the other de-trended light curves available for download at the MAST High Level Science Products archive. We find that EVEREST achieves the highest average precision of any of these pipelines for unsaturated K2 stars. The improved precision of these light curves will aid in exoplanet detection and characterization, investigations of stellar variability, asteroseismology, and other photometric studies. The EVEREST pipeline can also easily be applied to future surveys, such as the TESS mission, to correct for instrumental systematics and enable the detection of low signal-to-noise transiting exoplanets. The EVEREST light curves and the source code used to generate them are freely available online.

  18. Field-portable pixel super-resolution colour microscope.

    PubMed

    Greenbaum, Alon; Akbari, Najva; Feizi, Alborz; Luo, Wei; Ozcan, Aydogan

    2013-01-01

    Based on partially-coherent digital in-line holography, we report a field-portable microscope that can render lensfree colour images over a wide field-of-view of e.g., >20 mm(2). This computational holographic microscope weighs less than 145 grams with dimensions smaller than 17×6×5 cm, making it especially suitable for field settings and point-of-care use. In this lensfree imaging design, we merged a colorization algorithm with a source shifting based multi-height pixel super-resolution technique to mitigate 'rainbow' like colour artefacts that are typical in holographic imaging. This image processing scheme is based on transforming the colour components of an RGB image into YUV colour space, which separates colour information from brightness component of an image. The resolution of our super-resolution colour microscope was characterized using a USAF test chart to confirm sub-micron spatial resolution, even for reconstructions that employ multi-height phase recovery to handle dense and connected objects. To further demonstrate the performance of this colour microscope Papanicolaou (Pap) smears were also successfully imaged. This field-portable and wide-field computational colour microscope could be useful for tele-medicine applications in resource poor settings.

  19. Fully depleted, thick, monolithic CMOS pixels with high quantum efficiency

    NASA Astrophysics Data System (ADS)

    Clarke, A.; Stefanov, K.; Johnston, N.; Holland, A.

    2015-04-01

    The Centre for Electronic Imaging (CEI) has an active programme of evaluating and designing Complementary Metal-Oxide Semiconductor (CMOS) image sensors with high quantum efficiency, for applications in near-infrared and X-ray photon detection. This paper describes the performance characterisation of CMOS devices made on a high resistivity 50 μ m thick p-type substrate with a particular focus on determining the depletion depth and the quantum efficiency. The test devices contain 8 × 8 pixel arrays using CCD-style charge collection, which are manufactured in a low voltage CMOS process by ESPROS Photonics Corporation (EPC). Measurements include determining under which operating conditions the devices become fully depleted. By projecting a spot using a microscope optic and a LED and biasing the devices over a range of voltages, the depletion depth will change, causing the amount of charge collected in the projected spot to change. We determine if the device is fully depleted by measuring the signal collected from the projected spot. The analysis of spot size and shape is still under development.

  20. Improvement to the signaling interface for CMOS pixel sensors

    NASA Astrophysics Data System (ADS)

    Shi, Zhan; Tang, Zhenan; Feng, Chong; Cai, Hong

    2016-10-01

    The development of the readout speed of CMOS pixel sensors (CPS) is motivated by the demanding requirements of future high energy physics (HEP) experiments. As the interface between CPS and the data acquisition (DAQ) system, which inputs clock from the DAQ system and outputs data from CPS, the signaling interface should also be improved in terms of data rates. Meanwhile, the power consumption of the signaling interface should be maintained as low as possible. Consequently, a reduced swing differential signaling (RSDS) driver was adopted instead of a low-voltage differential signaling (LVDS) driver to transmit data from CPS to the DAQ system. In order to increase the capability of data rates, a serial source termination technique was employed. A LVDS/RSDS receiver was employed for transmitting clock from the DAQ system to CPS. A new method of generating hysteresis and a special current comparator were used to achieve a higher speed with lower power consumption. The signaling interface was designed and submitted for fabrication in a 0.18 μm CMOS image sensor (CIS) process. Measurement results indicate that the RSDS driver and the LVDS receiver can operate correctly at a data rate of 2 Gb/s with a power consumption of 19.1 mW.

  1. Smart-Pixel Array Processors Based on Optimal Cellular Neural Networks for Space Sensor Applications

    NASA Technical Reports Server (NTRS)

    Fang, Wai-Chi; Sheu, Bing J.; Venus, Holger; Sandau, Rainer

    1997-01-01

    A smart-pixel cellular neural network (CNN) with hardware annealing capability, digitally programmable synaptic weights, and multisensor parallel interface has been under development for advanced space sensor applications. The smart-pixel CNN architecture is a programmable multi-dimensional array of optoelectronic neurons which are locally connected with their local neurons and associated active-pixel sensors. Integration of the neuroprocessor in each processor node of a scalable multiprocessor system offers orders-of-magnitude computing performance enhancements for on-board real-time intelligent multisensor processing and control tasks of advanced small satellites. The smart-pixel CNN operation theory, architecture, design and implementation, and system applications are investigated in detail. The VLSI (Very Large Scale Integration) implementation feasibility was illustrated by a prototype smart-pixel 5x5 neuroprocessor array chip of active dimensions 1380 micron x 746 micron in a 2-micron CMOS technology.

  2. Robust autonomous detection of the defective pixels in detectors using a probabilistic technique.

    PubMed

    Ghosh, Siddhartha; Froebrich, Dirk; Freitas, Alex

    2008-12-20

    Detection of defective pixels in solid-state detectors/sensor arrays has received limited research attention. Few approaches currently exist for detecting the defective pixels using real images captured with cameras equipped with such detectors, and they are ad hoc and limited in their applicability. In this paper, we present a probabilistic novel integrated technique for autonomously detecting the defective pixels in image sensor arrays. It can be applied to images containing rich scene information, captured with any digital camera equipped with a solid-state detector, to detect different kinds of defective pixels in the detector. We apply our technique to the detection of various defective pixels in an experimental camera equipped with a charge coupled device (CCD) array and two out of the four HgCdTe detectors of the UKIRT's wide field camera (WFCAM) used for infrared (IR) astronomy [Astron. Astrophys.467, 777-784 (2007)]. PMID:19104544

  3. A novel CMOS digital pixel sensor for 1D barcode scanning

    NASA Astrophysics Data System (ADS)

    Yan, Mei; DeGeronimo, Gianluigi; O'Connor, Paul; Carlson, Bradley S.

    2004-06-01

    A 1-D CMOS digital pixel image sensor system architecture is presented. Each pixel contains a photodiode, a low-power charge-sensitive amplifier, low noise sample/hold circuit, an 8-bit single-slope ADC, a 12-bit shift register and timing & control logic. The pixel is laid out on a 4μm pitch to enable a cost efficient implementation of high-resolution pixel arrays. Fixed pattern noise (FPN) is reduced by a charge-sensitive feedback amplifier, and the reset noise is cancelled by correlated double sampling read out. A prototype chip containing 512 pixels has been fabricated in the TSMC .25um logic process. A 40μV/e- conversion gain is measured with 100 e- rms read noise.

  4. Development of a DC-DC conversion powering scheme for the CMS Phase-1 pixel upgrade

    NASA Astrophysics Data System (ADS)

    Feld, L.; Fimmers, C.; Karpinski, W.; Klein, K.; Lipinski, M.; Preuten, M.; Rauch, M.; Rittich, D.; Sammet, J.; Wlochal, M.

    2014-01-01

    A novel powering scheme based on the DC-DC conversion technique will be exploited to power the CMS Phase-1 pixel detector. DC-DC buck converters for the CMS pixel project have been developed, based on the AMIS5 ASIC designed by CERN. The powering system of the Phase-1 pixel detector is described and the performance of the converter prototypes is detailed, including power efficiency, stability of the output voltage, shielding, and thermal management. Results from a test of the magnetic field tolerance of the DC-DC converters are reported. System tests with pixel modules using many components of the future pixel barrel system are summarized. Finally first impressions from a pre-series of 200 DC-DC converters are presented.

  5. Electrical characterization of irradiated prototype silicon pixel sensors for BTeV

    SciTech Connect

    Maria Rita Coluccia et al.

    2002-11-13

    The pixel detector in the BteV experiment at the Tevatron (Fermi Laboratory) is an important detector component for high-resolution tracking and vertex identification. For this task the hybrid pixel detector has to work in a very harsh radiation environment with up to 10{sup 14} minimum ionizing particles/cm{sup 2}/year. Radiation hardness of prototype n{sup +}/n/p{sup +} silicon pixel sensors has been investigated. We present Electrical characterization curves for irradiated prototype n{sup +}/n/p{sup +} sensors, intended for use in the BTeV experiment. We tested pixel sensors from various vendors and with two pixel isolation techniques: p-stop and p-spray. Results are based on irradiation with 200 MeV protons up to 6 x 10{sup 14} protons/cm{sup 2}.

  6. Methods of editing cloud and atmospheric layer affected pixels from satellite data

    NASA Technical Reports Server (NTRS)

    Nixon, P. R. (Principal Investigator); Wiegand, C. L.; Richardson, A. J.; Johnson, M. P.; Goodier, B. G.

    1981-01-01

    The location and migration of cloud, land and water features were examined in spectral space (reflective VIS vs. emissive IR). Daytime HCMM data showed two distinct types of cloud affected pixels in the south Texas test area. High altitude cirrus and/or cirrostratus and "subvisible cirrus" (SCi) reflected the same or only slightly more than land features. In the emissive band, the digital counts ranged from 1 to over 75 and overlapped land features. Pixels consisting of cumulus clouds, or of mixed cumulus and landscape, clustered in a different area of spectral space than the high altitude cloud pixels. Cumulus affected pixels were more reflective than land and water pixels. In August the high altitude clouds and SCi were more emissive than similar clouds were in July. Four-channel TIROS-N data were examined with the objective of developing a multispectral screening technique for removing SCi contaminated data.

  7. Bilateral bad pixel and Stokes image reconstruction for microgrid polarimetric imagers

    NASA Astrophysics Data System (ADS)

    LeMaster, Daniel A.; Ratliff, Bradley M.

    2015-09-01

    Uncorrected or poorly corrected bad pixels reduce the effectiveness of polarimetric clutter suppression. In conventional microgrid processing, bad pixel correction is accomplished as a separate step from Stokes image reconstruction. Here, these two steps are combined to speed processing and provide better estimates of the entire image, including missing samples. A variation on the bilateral filter enables both edge preservation in the Stokes imagery and bad pixel suppression. Understanding the newly presented filter requires two key insights. First, the adaptive nature of the bilateral filter is extended to correct for bad pixels by simply incorporating a bad pixel mask. Second, the bilateral filter for Stokes estimation is the sum of the normalized bilateral filters for estimating each analyzer channel individually. This paper describes the new approach and compares it to our legacy method using simulated imagery.

  8. Commissioning of the upgraded ATLAS Pixel Detector for Run2 at LHC

    NASA Astrophysics Data System (ADS)

    Dobos, Daniel

    2016-07-01

    The Pixel Detector of the ATLAS experiment has shown excellent performance during the whole Run-1 of LHC. Taking advantage of the long showdown, the detector was extracted from the experiment and brought to the surface, to equip it with new service quarter panels, to repair modules and to ease installation of the Insertable B-Layer, a fourth layer of pixel detectors, installed in May 2014 between the existing Pixel Detector and a new smaller radius beam-pipe at a radius of 3.3 cm. To cope with the high radiation and pixel occupancy due to the proximity to the interaction point, a new read-out chip and two different silicon sensor technologies (planar and 3D) have been developed. An overview of the refurbishing of the Pixel Detector and of the IBL project as well as early performance tests using cosmic rays and beam data will be presented.

  9. MONOLITHIC ACTIVE PIXEL MATRIX WITH BINARY COUNTERS IN AN SOI PROCESS.

    SciTech Connect

    DUPTUCH,G.; YAREMA, R.

    2007-06-07

    The design of a Prototype monolithic active pixel matrix, designed in a 0.15 {micro}m CMOS SOI Process, is presented. The process allowed connection between the electronics and the silicon volume under the layer of buried oxide (BOX). The small size vias traversing through the BOX and implantation of small p-type islands in the n-type bulk result in a monolithic imager. During the acquisition time, all pixels register individual radiation events incrementing the counters. The counting rate is up to 1 MHz per pixel. The contents of counters are shifted out during the readout phase. The designed prototype is an array of 64 x 64 pixels and the pixel size is 26 x 26 {micro}m{sup 2}.

  10. Laser pixelation of thick scintillators for medical imaging applications: x-ray studies

    NASA Astrophysics Data System (ADS)

    Sabet, Hamid; Kudrolli, Haris; Marton, Zsolt; Singh, Bipin; Nagarkar, Vivek V.

    2013-09-01

    To achieve high spatial resolution required in nuclear imaging, scintillation light spread has to be controlled. This has been traditionally achieved by introducing structures in the bulk of scintillation materials; typically by mechanical pixelation of scintillators and fill the resultant inter-pixel gaps by reflecting materials. Mechanical pixelation however, is accompanied by various cost and complexity issues especially for hard, brittle and hygroscopic materials. For example LSO and LYSO, hard and brittle scintillators of interest to medical imaging community, are known to crack under thermal and mechanical stress; the material yield drops quickly with large arrays with high aspect ratio pixels and therefore the pixelation process cost increases. We are utilizing a novel technique named Laser Induced Optical Barriers (LIOB) for pixelation of scintillators that overcomes the issues associated with mechanical pixelation. In this technique, we can introduce optical barriers within the bulk of scintillator crystals to form pixelated arrays with small pixel size and large thickness. We applied LIOB to LYSO using a high-frequency solid-state laser. Arrays with different crystal thickness (5 to 20 mm thick), and pixel size (0.8×0.8 to 1.5×1.5 mm2) were fabricated and tested. The width of the optical barriers were controlled by fine-tuning key parameters such as lens focal spot size and laser energy density. Here we report on LIOB process, its optimization, and the optical crosstalk measurements using X-rays. There are many applications that can potentially benefit from LIOB including but not limited to clinical/pre-clinical PET and SPECT systems, and photon counting CT detectors.

  11. Efficient implementation of the adaptive scale pixel decomposition algorithm

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Bhatnagar, S.; Rau, U.; Zhang, M.

    2016-08-01

    Context. Most popular algorithms in use to remove the effects of a telescope's point spread function (PSF) in radio astronomy are variants of the CLEAN algorithm. Most of these algorithms model the sky brightness using the delta-function basis, which results in undesired artefacts when used to image extended emission. The adaptive scale pixel decomposition (Asp-Clean) algorithm models the sky brightness on a scale-sensitive basis and thus gives a significantly better imaging performance when imaging fields that contain both resolved and unresolved emission. Aims: However, the runtime cost of Asp-Clean is higher than that of scale-insensitive algorithms. In this paper, we identify the most expensive step in the original Asp-Clean algorithm and present an efficient implementation of it, which significantly reduces the computational cost while keeping the imaging performance comparable to the original algorithm. The PSF sidelobe levels of modern wide-band telescopes are significantly reduced, allowing us to make approximations to reduce the computational cost, which in turn allows for the deconvolution of larger images on reasonable timescales. Methods: As in the original algorithm, scales in the image are estimated through function fitting. Here we introduce an analytical method to model extended emission, and a modified method for estimating the initial values used for the fitting procedure, which ultimately leads to a lower computational cost. Results: The new implementation was tested with simulated EVLA data and the imaging performance compared well with the original Asp-Clean algorithm. Tests show that the current algorithm can recover features at different scales with lower computational cost.

  12. 128x128-pixel long-wavelength infrared acquisition camera

    NASA Astrophysics Data System (ADS)

    Levan, Paul D.; Colucci, D'nardo; Cowan, William D.; Figie, Brian D.; Stewart, Eric J.

    1994-07-01

    This paper describes a Phillips Laboratory internal design for a high sensitivity, large field of view IR acquisition camera. Currently, the acquisition of a satellite with the 1.5 meter telescope of the Starfire Optical Range typically requires a sunlit target and dark sky. However, the level of thermal radiation from such a satellite is often sufficiently high in the long wavelength IR (LWIR) to permit detection with ground based telescopes irrespective of target illumination. The drawbacks of LWIR acquisition include the high levels of thermal radiation from both the telescope and the atmosphere which pose two constraints: (1), the 'background signal' usually exceeds the target signal and must be removed on time scales over which it is relatively constant, and (2), associated with the background signal is a noise level that dominates all system noise sources. The background signal level at the detector array for our application varies between 1015 to 1016 photons sec-1 cm-2, depending on the IR bandpass used. Our optical design for the LWIR acquisition camera maps a 128x128 pixel detector array onto a two milliradian (mrad) scene. The optical design uses two aspheric lenses, one to re-image the field onto a cold field stop, and the telescope pupil onto a cryogenic chopping mirror and collocated radiation stop. The second lens re-images the field stop onto the detector array. Aberrations are designed to be better than diffraction limited over the entire two mrad field of view. The end product of the acquisition system is a video display of the IR scene, with the background signal removed. A user then positions mouse-driven cross hairs over a target in the scene. The resulting position and time update is used to revise the target ephemeris, and to provide pointing information for target acquisition by other SOR tracking platforms.

  13. A 128 × 128 Pixel Complementary Metal Oxide Semiconductor Image Sensor with an Improved Pixel Architecture for Detecting Modulated Light Signals

    NASA Astrophysics Data System (ADS)

    Yamamoto, Koji; Oya, Yu; Kagawa, Keiichiro; Nunoshita, Masahiro; Ohta, Jun; Watanabe, Kunihiro

    A complementary metal oxide semiconductor (CMOS) image sensor for the detection of modulated light under background illumination has been developed. When an object is illuminated by a modulated light source under background illumination the sensor enables the object alone to be captured. This paper describes improvements in pixel architecture for reducing fixed pattern noise (FPN) and improving the sensitivity of the image sensor. The improved 128 × 128 pixel CMOS image sensor with a column parallel analog-to-digital converter (ADC) circuit was fabricated using 0.35-mm CMOS technology. The resulting captured images are shown and the properties of improved pixel architecture are described. The image sensor has FPN of 1/28 that of the previous image sensor and an improved pixel architecture comprising a common in-pixel amp and a correlated double sampling (CDS) circuit. The use of a split photogate increases the sensitivity of the image sensor to 1.3 times that of the previous image sensor.

  14. Reduced utilization of Man5GlcNAc2-P-P-lipid in a Lec9 mutant of Chinese hamster ovary cells: analysis of the steps in oligosaccharide-lipid assembly.

    PubMed

    Hall, C W; McLachlan, K R; Krag, S S; Robbins, A R

    1997-11-01

    Recently we reported that CHB11-1-3, a Chinese hamster ovary cell mutant defective in glycosylation of asparagine-linked proteins, is defective in the synthesis of dolichol [Quellhorst et al., 343:19-26, 1997: Arch Biochem Biophys]. CHB11-1-3 was found to be in the Lec9 complementation group, which synthesizes polyprenol rather than dolichol. In this paper, levels of various polyprenyl derivatives in CHB11-1-3 are compared to levels of the corresponding dolichyl derivatives in parental cells. CHB11-1-3 was found to maintain near normal levels of Man5GlcNAc2-P-P-polyprenol and mannosylphosphorylpolyprenol, despite reduced rates of synthesis, by utilizing those intermediates at a reduced rate. The Man5GlcNAc2 oligosaccharide attached to prenol in CHB11-1-3 cells and to dolichol in parental cells is the same structure, as determined by acetolysis. Man5GlcNAc2-P-P-polyprenol and Man5GlcNAc5-P-P-dolichol both appeared to be translocated efficiently in an in vitro reaction. Glycosylation of G protein was compared in vesicular stomatitus virus (VSV)-infected parent and mutant; although a portion of G protein was compared in vesicular stomatitus virus (VSV)-infected parent and mutant; although a portion of G protein was normally glycosylated in CHB11-1-3 cells, a large portion of G was underglycosylated, resulting in the addition of either one or no oligosaccharide to G. Addition of a single oligosaccharide occurred randomly rather than preferentially at one of the two sites.

  15. The upgraded Pixel Detector of the ATLAS Experiment for Run 2 at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Backhaus, M.

    2016-09-01

    During Run 1 of the Large Hadron Collider (LHC), the ATLAS Pixel Detector has shown excellent performance. The ATLAS collaboration took advantage of the first long shutdown of the LHC during 2013 and 2014 and extracted the ATLAS Pixel Detector from the experiment, brought it to surface and maintained the services. This included the installation of new service quarter panels, the repair of cables, and the installation of the new Diamond Beam Monitor (DBM). Additionally, a completely new innermost pixel detector layer, the Insertable B-Layer (IBL), was constructed and installed in May 2014 between a new smaller beam pipe and the existing Pixel Detector. With a radius of 3.3 cm the IBL is located extremely close to the interaction point. Therefore, a new readout chip and two new sensor technologies (planar and 3D) are used in the IBL. In order to achieve best possible physics performance the material budget was improved with respect to the existing Pixel Detector. This is realized using lightweight staves for mechanical support and a CO2 based cooling system. This paper describes the improvements achieved during the maintenance of the existing Pixel Detector as well as the performance of the IBL during the construction and commissioning phase. Additionally, first results obtained during the LHC Run 2 demonstrating the distinguished tracking performance of the new Four Layer ATLAS Pixel Detector are presented.

  16. Fast distributed large-pixel-count hologram computation using a GPU cluster.

    PubMed

    Pan, Yuechao; Xu, Xuewu; Liang, Xinan

    2013-09-10

    Large-pixel-count holograms are one essential part for big size holographic three-dimensional (3D) display, but the generation of such holograms is computationally demanding. In order to address this issue, we have built a graphics processing unit (GPU) cluster with 32.5 Tflop/s computing power and implemented distributed hologram computation on it with speed improvement techniques, such as shared memory on GPU, GPU level adaptive load balancing, and node level load distribution. Using these speed improvement techniques on the GPU cluster, we have achieved 71.4 times computation speed increase for 186M-pixel holograms. Furthermore, we have used the approaches of diffraction limits and subdivision of holograms to overcome the GPU memory limit in computing large-pixel-count holograms. 745M-pixel and 1.80G-pixel holograms were computed in 343 and 3326 s, respectively, for more than 2 million object points with RGB colors. Color 3D objects with 1.02M points were successfully reconstructed from 186M-pixel hologram computed in 8.82 s with all the above three speed improvement techniques. It is shown that distributed hologram computation using a GPU cluster is a promising approach to increase the computation speed of large-pixel-count holograms for large size holographic display.

  17. Simultaneous real-time visible and infrared video with single-pixel detectors

    NASA Astrophysics Data System (ADS)

    Edgar, Matthew. P.; Gibson, Graham M.; Bowman, Richard W.; Sun, Baoqing; Radwell, Neal; Mitchell, Kevin J.; Welsh, Stephen S.; Padgett, Miles J.

    2015-05-01

    Conventional cameras rely upon a pixelated sensor to provide spatial resolution. An alternative approach replaces the sensor with a pixelated transmission mask encoded with a series of binary patterns. Combining knowledge of the series of patterns and the associated filtered intensities, measured by single-pixel detectors, allows an image to be deduced through data inversion. In this work we extend the concept of a ‘single-pixel camera’ to provide continuous real-time video at 10 Hz , simultaneously in the visible and short-wave infrared, using an efficient computer algorithm. We demonstrate our camera for imaging through smoke, through a tinted screen, whilst performing compressive sampling and recovering high-resolution detail by arbitrarily controlling the pixel-binning of the masks. We anticipate real-time single-pixel video cameras to have considerable importance where pixelated sensors are limited, allowing for low-cost, non-visible imaging systems in applications such as night-vision, gas sensing and medical diagnostics.

  18. Development of a mixed pixel filter for improved dimension estimation using AMCW laser scanner

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Sohn, Hoon; Cheng, Jack C. P.

    2016-09-01

    Accurate dimension estimation is desired in many fields, but the traditional dimension estimation methods are time-consuming and labor-intensive. In the recent decades, 3D laser scanners have become popular for dimension estimation due to their high measurement speed and accuracy. Nonetheless, scan data obtained by amplitude-modulated continuous-wave (AMCW) laser scanners suffer from erroneous data called mixed pixels, which can influence the accuracy of dimension estimation. This study develops a mixed pixel filter for improved dimension estimation using AMCW laser scanners. The distance measurement of mixed pixels is firstly formulated based on the working principle of laser scanners. Then, a mixed pixel filter that can minimize the classification errors between valid points and mixed pixels is developed. Validation experiments were conducted to verify the formulation of the distance measurement of mixed pixels and to examine the performance of the proposed mixed pixel filter. Experimental results show that, for a specimen with dimensions of 840 mm × 300 mm, the overall errors of the dimensions estimated after applying the proposed filter are 1.9 mm and 1.0 mm for two different scanning resolutions, respectively. These errors are much smaller than the errors (4.8 mm and 3.5 mm) obtained by the scanner's built-in filter.

  19. Improving Photometry and Stellar Signal Preservation with Pixel-Level Systematic Error Correction

    NASA Technical Reports Server (NTRS)

    Kolodzijczak, Jeffrey J.; Smith, Jeffrey C.; Jenkins, Jon M.

    2013-01-01

    The Kepler Mission has demonstrated that excellent stellar photometric performance can be achieved using apertures constructed from optimally selected CCD pixels. The clever methods used to correct for systematic errors, while very successful, still have some limitations in their ability to extract long-term trends in stellar flux. They also leave poorly correlated bias sources, such as drifting moiré pattern, uncorrected. We will illustrate several approaches where applying systematic error correction algorithms to the pixel time series, rather than the co-added raw flux time series, provide significant advantages. Examples include, spatially localized determination of time varying moiré pattern biases, greater sensitivity to radiation-induced pixel sensitivity drops (SPSDs), improved precision of co-trending basis vectors (CBV), and a means of distinguishing the stellar variability from co-trending terms even when they are correlated. For the last item, the approach enables physical interpretation of appropriately scaled coefficients derived in the fit of pixel time series to the CBV as linear combinations of various spatial derivatives of the pixel response function (PRF). We demonstrate that the residuals of a fit of soderived pixel coefficients to various PRF-related components can be deterministically interpreted in terms of physically meaningful quantities, such as the component of the stellar flux time series which is correlated with the CBV, as well as, relative pixel gain, proper motion and parallax. The approach also enables us to parameterize and assess the limiting factors in the uncertainties in these quantities.

  20. Human vision-based algorithm to hide defective pixels in LCDs

    NASA Astrophysics Data System (ADS)

    Kimpe, Tom; Coulier, Stefaan; Van Hoey, Gert

    2006-02-01

    Producing displays without pixel defects or repairing defective pixels is technically not possible at this moment. This paper presents a new approach to solve this problem: defects are made invisible for the user by using image processing algorithms based on characteristics of the human eye. The performance of this new algorithm has been evaluated using two different methods. First of all the theoretical response of the human eye was analyzed on a series of images and this before and after applying the defective pixel compensation algorithm. These results show that indeed it is possible to mask a defective pixel. A second method was to perform a psycho-visual test where users were asked whether or not a defective pixel could be perceived. The results of these user tests also confirm the value of the new algorithm. Our "defective pixel correction" algorithm can be implemented very efficiently and cost-effectively as pixel-dataprocessing algorithms inside the display in for instance an FPGA, a DSP or a microprocessor. The described techniques are also valid for both monochrome and color displays ranging from high-quality medical displays to consumer LCDTV applications.

  1. PImMS, a fast event-triggered monolithic pixel detector with storage of multiple timestamps

    NASA Astrophysics Data System (ADS)

    John, J. J.; Brouard, M.; Clark, A.; Crooks, J.; Halford, E.; Hill, L.; Lee, J. W. L.; Nomerotski, A.; Pisarczyk, R.; Sedgwick, I.; Slater, C. S.; Turchetta, R.; Vallance, C.; Wilman, E.; Winter, B.; Yuen, W. H.

    2012-08-01

    PImMS, or Pixel Imaging Mass Spectrometry, is a novel high-speed monolithic CMOS imaging sensor tailored to mass spectrometry requirements, also suitable for other dark-field applications. In its application to time-of-flight mass spectrometry, the sensor permits ion arrival time distributions to be combined with 2D imaging, providing additional information about the initial position or velocity of ions under study. PImMS1, the first generation sensor in this family, comprises an array of 72 by 72 pixels on a 70 μm by 70 μm pitch. Pixels independently record digital timestamps when events occur over an adjustable threshold. Each pixel contains 4 memories to record timestamps at a resolution of 25 ns. The sensor was designed and manufactured in the INMAPS 0.18 μm process. This allows the inclusion of significant amounts of circuitry (over 600 transistors) within each pixel while maintaining good detection efficiency. We present an overview of the pixel and sensor architecture, explain its functioning and present test results, ranging from characterisation of the analogue front end of the pixel, to verification of its digital functions, to some first images captured on mass spectrometers. We conclude with an overview of the upcoming second generation of PImMS sensors.

  2. Simultaneous real-time visible and infrared video with single-pixel detectors.

    PubMed

    Edgar, Matthew P; Gibson, Graham M; Bowman, Richard W; Sun, Baoqing; Radwell, Neal; Mitchell, Kevin J; Welsh, Stephen S; Padgett, Miles J

    2015-01-01

    Conventional cameras rely upon a pixelated sensor to provide spatial resolution. An alternative approach replaces the sensor with a pixelated transmission mask encoded with a series of binary patterns. Combining knowledge of the series of patterns and the associated filtered intensities, measured by single-pixel detectors, allows an image to be deduced through data inversion. In this work we extend the concept of a 'single-pixel camera' to provide continuous real-time video at 10 Hz , simultaneously in the visible and short-wave infrared, using an efficient computer algorithm. We demonstrate our camera for imaging through smoke, through a tinted screen, whilst performing compressive sampling and recovering high-resolution detail by arbitrarily controlling the pixel-binning of the masks. We anticipate real-time single-pixel video cameras to have considerable importance where pixelated sensors are limited, allowing for low-cost, non-visible imaging systems in applications such as night-vision, gas sensing and medical diagnostics. PMID:26001092

  3. Automatic Extraction of Closed Pixel Clusters for Target Cueing in Hyperspectral Images

    SciTech Connect

    Paglieroni, D W; Perkins, D E

    2001-06-05

    Traditional algorithms for automatic target cueing (ATC) in hyperspectral images, such as the RX algorithm, treat anomaly detection as a simple hypothesis testing problem. Each decision threshold gives rise to a different set of anomalous pixels. The clustered Rx algorithm generates target cues by grouping anomalous pixels into spatial clusters, and retaining only those clusters that satisfy target specific spatial constraints. It produces one set of target cues for each of several decision thresholds, and conservatively requires {Omicron}(K{sup 2}) operations per pixel, where K is the number of spectral bands (which varies from hundreds to thousands in hyperspectral images). A novel ATC algorithm, known as ''Pixel Cluster Cueing'' (PCC), is discussed. PCC groups pixels into clusters based on spectral similarity and spatial proximity, and then selects only those clusters that satisfy target-specific spatial constraints as target cues. PCC requires only {Omicron}(K) operations per pixel, and it produces only one set of target cues because it is not an anomaly detection algorithm, i.e., it does not use a decision threshold to classify individual pixels as anomalies. PCC is compared both computationally and statistically to the RX algorithm.

  4. Design, optimization and evaluation of a "smart" pixel sensor array for low-dose digital radiography

    NASA Astrophysics Data System (ADS)

    Wang, Kai; Liu, Xinghui; Ou, Hai; Chen, Jun

    2016-04-01

    Amorphous silicon (a-Si:H) thin-film transistors (TFTs) have been widely used to build flat-panel X-ray detectors for digital radiography (DR). As the demand for low-dose X-ray imaging grows, a detector with high signal-to-noise-ratio (SNR) pixel architecture emerges. "Smart" pixel is intended to use a dual-gate photosensitive TFT for sensing, storage, and switch. It differs from a conventional passive pixel sensor (PPS) and active pixel sensor (APS) in that all these three functions are combined into one device instead of three separate units in a pixel. Thus, it is expected to have high fill factor and high spatial resolution. In addition, it utilizes the amplification effect of the dual-gate photosensitive TFT to form a one-transistor APS that leads to a potentially high SNR. This paper addresses the design, optimization and evaluation of the smart pixel sensor and array for low-dose DR. We will design and optimize the smart pixel from the scintillator to TFT levels and validate it through optical and electrical simulation and experiments of a 4x4 sensor array.

  5. Simultaneous real-time visible and infrared video with single-pixel detectors.

    PubMed

    Edgar, Matthew P; Gibson, Graham M; Bowman, Richard W; Sun, Baoqing; Radwell, Neal; Mitchell, Kevin J; Welsh, Stephen S; Padgett, Miles J

    2015-01-01

    Conventional cameras rely upon a pixelated sensor to provide spatial resolution. An alternative approach replaces the sensor with a pixelated transmission mask encoded with a series of binary patterns. Combining knowledge of the series of patterns and the associated filtered intensities, measured by single-pixel detectors, allows an image to be deduced through data inversion. In this work we extend the concept of a 'single-pixel camera' to provide continuous real-time video at 10 Hz , simultaneously in the visible and short-wave infrared, using an efficient computer algorithm. We demonstrate our camera for imaging through smoke, through a tinted screen, whilst performing compressive sampling and recovering high-resolution detail by arbitrarily controlling the pixel-binning of the masks. We anticipate real-time single-pixel video cameras to have considerable importance where pixelated sensors are limited, allowing for low-cost, non-visible imaging systems in applications such as night-vision, gas sensing and medical diagnostics.

  6. Electrical characterization of CMOS 1T charge-modulation pixel in two design configurations

    NASA Astrophysics Data System (ADS)

    Tournier, Arnaud; Roy, François; Lu, Guo-Neng; Deschamps, Benoît

    2008-02-01

    To evaluate electrical characteristics of the 1T charge-modulation pixel, we propose two design configurations: one is a 2.2μm-pitch, rectangular-gate pixel, and the other is a 1.4μm-pitch, ring-gate pixel. The former allows the transistor size to be minimized, but requires surrounding STI (Shallow Trench Isolation) to reduce electrical crosstalk. The latter is advantageous in terms of pixel size and fill factor, mainly thanks to STI suppression. The two design configurations are respectively integrated in test chips. Our measured results confirm the scaling law: reducing pixel size improves conversion gain, but degrades full well capacity (FWC). They also show that dark current of the 1.4μm-pitch ring-gate pixel is much lower than the 2.2μm-pitch rectangular-gate counterpart. This low dark current achievement may be explained by: i) suppression of STI-induced surface leakage current component, ii) smooth-shape layout to minimize band-to-band tunneling effect, and iii) smaller pixel size with smaller depletion areas which has, accordingly, lower thermally-generated dark current components. The 1.4μm-pitch ring-gate pixel also has lower noise, especially much lower dark FPN. This seems to confirm that dark FPN may have a large contribution from dark current generation. The dynamic range for the 1.4μm-pitch pixel is larger, meaning that signal-to-noise ratio outweighs FWC degradation. However, the sensitivity, like FWC, is also degraded in the same proportion. There are possibilities of improvements especially by process optimization.

  7. Charge Loss and Charge Sharing Measurements for Two Different Pixelated Cadmium-Zinc-Telluride Detectors

    NASA Technical Reports Server (NTRS)

    Gaskin, Jessica; Sharma, Dharma; Ramsey, Brian; Seller, Paul

    2003-01-01

    As part of ongoing research at Marshall Space Flight Center, Cadmium-Zinc- Telluride (CdZnTe) pixilated detectors are being developed for use at the focal plane of the High Energy Replicated Optics (HERO) telescope. HERO requires a 64x64 pixel array with a spatial resolution of around 200 microns (with a 6m focal length) and high energy resolution (< 2% at 60keV). We are currently testing smaller arrays as a necessary first step towards this goal. In this presentation, we compare charge sharing and charge loss measurements between two devices that differ both electronically and geometrically. The first device consists of a 1-mm-thick piece of CdZnTe that is sputtered with a 4x4 array of pixels with pixel pitch of 750 microns (inter-pixel gap is 100 microns). The signal is read out using discrete ultra-low-noise preamplifiers, one for each of the 16 pixels. The second detector consists of a 2-mm-thick piece of CdZnTe that is sputtered with a 16x16 array of pixels with a pixel pitch of 300 microns (inter-pixel gap is 50 microns). Instead of using discrete preamplifiers, the crystal is bonded to an ASIC that provides all of the front-end electronics to each of the 256 pixels. what degree the bias voltage (i.e. the electric field) and hence the drift and diffusion coefficients affect our measurements. Further, we compare the measured results with simulated results and discuss to

  8. Development of n-in-p pixel modules for the ATLAS upgrade at HL-LHC

    NASA Astrophysics Data System (ADS)

    Macchiolo, A.; Nisius, R.; Savic, N.; Terzo, S.

    2016-09-01

    Thin planar pixel modules are promising candidates to instrument the inner layers of the new ATLAS pixel detector for HL-LHC, thanks to the reduced contribution to the material budget and their high charge collection efficiency after irradiation. 100-200 μm thick sensors, interconnected to FE-I4 read-out chips, have been characterized with radioactive sources and beam tests at the CERN-SPS and DESY. The results of these measurements are reported for devices before and after irradiation up to a fluence of 14 ×1015 neq /cm2 . The charge collection and tracking efficiency of the different sensor thicknesses are compared. The outlook for future planar pixel sensor production is discussed, with a focus on sensor design with the pixel pitches (50×50 and 25×100 μm2) foreseen for the RD53 Collaboration read-out chip in 65 nm CMOS technology. An optimization of the biasing structures in the pixel cells is required to avoid the hit efficiency loss presently observed in the punch-through region after irradiation. For this purpose the performance of different layouts have been compared in FE-I4 compatible sensors at various fluence levels by using beam test data. Highly segmented sensors will represent a challenge for the tracking in the forward region of the pixel system at HL-LHC. In order to reproduce the performance of 50×50 μm2 pixels at high pseudo-rapidity values, FE-I4 compatible planar pixel sensors have been studied before and after irradiation in beam tests at high incidence angle (80°) with respect to the short pixel direction. Results on cluster shapes, charge collection and hit efficiency will be shown.

  9. Study on pixel matching method of the multi-angle observation from airborne AMPR measurements

    NASA Astrophysics Data System (ADS)

    Hou, Weizhen; Qie, Lili; Li, Zhengqiang; Sun, Xiaobing; Hong, Jin; Chen, Xingfeng; Xu, Hua; Sun, Bin; Wang, Han

    2015-10-01

    For the along-track scanning mode, the same place along the ground track could be detected by the Advanced Multi-angular Polarized Radiometer (AMPR) with several different scanning angles from -55 to 55 degree, which provides a possible means to get the multi-angular detection for some nearby pixels. However, due to the ground sample spacing and spatial footprint of the detection, the different sizes of footprints cannot guarantee the spatial matching of some partly overlap pixels, which turn into a bottleneck for the effective use of the multi-angular detected information of AMPR to study the aerosol and surface polarized properties. Based on our definition and calculation of t he pixel coincidence rate for the multi-angular detection, an effective multi-angle observation's pixel matching method is presented to solve the spatial matching problem for airborne AMPR. Assuming the shape of AMPR's each pixel is an ellipse, and the major axis and minor axis depends on the flying attitude and each scanning angle. By the definition of coordinate system and origin of coordinate, the latitude and longitude could be transformed into the Euclidian distance, and the pixel coincidence rate of two nearby ellipses could be calculated. Via the traversal of each ground pixel, those pixels with high coincidence rate could be selected and merged, and with the further quality control of observation data, thus the ground pixels dataset with multi-angular detection could be obtained and analyzed, providing the support for the multi-angular and polarized retrieval algorithm research in t he next study.

  10. HUBBLE SPACE TELESCOPE PIXEL ANALYSIS OF THE INTERACTING S0 GALAXY NGC 5195 (M51B)

    SciTech Connect

    Lee, Joon Hyeop; Kim, Sang Chul; Ree, Chang Hee; Kim, Minjin; Jeong, Hyunjin; Lee, Jong Chul; Kyeong, Jaemann E-mail: sckim@kasi.re.kr E-mail: mkim@kasi.re.kr E-mail: jclee@kasi.re.kr

    2012-08-01

    We report the properties of the interacting S0 galaxy NGC 5195 (M51B), revealed in a pixel analysis using the Hubble Space Telescope/Advanced Camera for Surveys images in the F435W, F555W, and F814W (BVI) bands. We analyze the pixel color-magnitude diagram (pCMD) of NGC 5195, focusing on the properties of its red and blue pixel sequences and the difference from the pCMD of NGC 5194 (M51A; the spiral galaxy interacting with NGC 5195). The red pixel sequence of NGC 5195 is redder than that of NGC 5194, which corresponds to the difference in the dust optical depth of 2 < {Delta}{tau}{sub V} < 4 at fixed age and metallicity. The blue pixel sequence of NGC 5195 is very weak and spatially corresponds to the tidal bridge between the two interacting galaxies. This implies that the blue pixel sequence is not an ordinary feature in the pCMD of an early-type galaxy, but that it is a transient feature of star formation caused by the galaxy-galaxy interaction. We also find a difference in the shapes of the red pixel sequences on the pixel color-color diagrams (pCCDs) of NGC 5194 and NGC 5195. We investigate the spatial distributions of the pCCD-based pixel stellar populations. The young population fraction in the tidal bridge area is larger than that in other areas by a factor >15. Along the tidal bridge, young populations seem to be clumped particularly at the middle point of the bridge. On the other hand, the dusty population shows a relatively wide distribution between the tidal bridge and the center of NGC 5195.

  11. HST/WFC3 Characteristics: gain, post-flash stability, UVIS low-sensitivity pixels, persistence, IR flats and bad pixel table

    NASA Astrophysics Data System (ADS)

    Gunning, Heather C.; Baggett, Sylvia; Gosmeyer, Catherine M.; Long, Knox S.; Ryan, Russell E.; MacKenty, John W.; Durbin, Meredith

    2015-08-01

    The Wide Field Camera 3 (WFC3) is a fourth-generation imaging instrument on the Hubble Space Telescope (HST). Installed in May 2009, WFC3 is comprised of two observational channels covering wavelengths from UV/Visible (UVIS) to infrared (IR); both have been performing well on-orbit. We discuss the gain stability of both WFC3 channel detectors from ground testing through present day. For UVIS, we detail a low-sensitivity pixel population that evolves during the time between anneals, but is largely reset by the annealing procedure. We characterize the post-flash LED lamp stability, used and recommended to mitigate CTE effects for observations with less than 12e-/pixel backgrounds. We present mitigation options for IR persistence during and after observations. Finally, we give an overview on the construction of the IR flats and provide updates on the bad pixel table.

  12. Pixel partition method using Markov random field for measurements of closely spaced objects by optical sensors

    NASA Astrophysics Data System (ADS)

    Wang, Xueying; Li, Jun; Sheng, Weidong; An, Wei; Du, Qinfeng

    2015-10-01

    ABSTRACT In Space-based optical system, during the tracking for closely spaced objects (CSOs), the traditional method with a constant false alarm rate(CFAR) detecting brings either more clutter measurements or the loss of target information. CSOs can be tracked as Extended targets because their features on optical sensor's pixel-plane. A pixel partition method under the framework of Markov random field(MRF) is proposed, simulation results indicate: the method proposed provides higher pixel partition performance than traditional method, especially when the signal-noise-rate is poor.

  13. The pixel rectangle index used in object based building extraction from high resolution images

    NASA Astrophysics Data System (ADS)

    Cui, W. H.; Feng, X.; Qin, K.

    2014-03-01

    An improved high resolution object-based building extraction method based on Pixel Rectangle Index is presented in this paper. We use Minimum Span Tree optimal theory to realize object-based high resolution image segmentation. First, we proposed a rotation invariant Pixel Rectangle Index by introducing the principal direction of homogeneous area. Second, we improved the calculation of edge-weight by introducing the band-weight and Pixel Rectangle Index. The QuickBird high resolution images were used to do the building extraction experiment. The experiment result proved that this method can obtain high extraction accuracy and this algorithm can be efficiently used in remote sensing images.

  14. A programmable, low noise, multichannel asic for readout of pixelated amorphous silicon arrays

    SciTech Connect

    Yarema, R. J.

    1998-08-01

    Pixelated amorphous silicon arrays used for detecting X-rays have a number of special requirements for the readout electronics. Because the pixel detector is a high density array, custom integrated circuits are very desirable for reading out the column signals and addressing the rows of pixels to be read out. In practice, separate chips are used for readout and addressing. This paper discusses a custom integrated circuit for processing the analog column signals. The chip has 32 channels of low noise integrators followed by sample and hold circuits which perform a correlated double sample. The chip has several programmable features including gain, bandwidth, and readout configuration.

  15. Energy-recycling pixel for active-matrix organic light-emitting diode display

    NASA Astrophysics Data System (ADS)

    Yang, Che-Yu; Cho, Ting-Yi; Chen, Yen-Yu; Yang, Chih-Jen; Meng, Chao-Yu; Yang, Chieh-Hung; Yang, Po-Chuan; Chang, Hsu-Yu; Hsueh, Chun-Yuan; Wu, Chung-Chih; Lee, Si-Chen

    2007-06-01

    The authors report a pixel structure for active-matrix organic light-emitting diode (OLED) displays that has a hydrogenated amorphous silicon solar cell inserted between the driving polycrystalline Si thin-film transistor and the pixel OLED. Such an active-matrix OLED pixel structure not only exhibits a reduced reflection (and thus improved contrast) compared to conventional OLEDs but also is capable of recycling both incident photon energies and internally generated OLED radiation. Such a feature of energy recycling may be of use for portable/mobile electronics, which are particularly power aware.

  16. Restoration of hot pixels in digital imagers using lossless approximation techniques

    NASA Astrophysics Data System (ADS)

    Hadar, O.; Shleifer, A.; Cohen, E.; Dotan, Y.

    2015-09-01

    During the last twenty years, digital imagers have spread into industrial and everyday devices, such as satellites, security cameras, cell phones, laptops and more. "Hot pixels" are the main defects in remote digital cameras. In this paper we prove an improvement of existing restoration methods that use (solely or as an auxiliary tool) some average of the surrounding single pixel, such as the method of the Chapman-Koren study 1,2. The proposed method uses the CALIC algorithm and adapts it to a full use of the surrounding pixels.

  17. Beam test results of the BTeV silicon pixel detector

    SciTech Connect

    Gabriele Chiodini et al.

    2000-09-28

    The authors have described the results of the BTeV silicon pixel detector beam test. The pixel detectors under test used samples of the first two generations of Fermilab pixel readout chips, FPIX0 and FPIX1, (indium bump-bonded to ATLAS sensor prototypes). The spatial resolution achieved using analog charge information is excellent for a large range of track inclination. The resolution is still very good using only 2-bit charge information. A relatively small dependence of the resolution on bias voltage is observed. The resolution is observed to depend dramatically on the discriminator threshold, and it deteriorates rapidly for threshold above 4000e{sup {minus}}.

  18. Low-power clock distribution circuits for the Macro Pixel ASIC

    NASA Astrophysics Data System (ADS)

    Gaioni, L.; De Canio, F.; Manghisoni, M.; Ratti, L.; Re, V.; Traversi, G.; Marchioro, A.; Kloukinas, K.

    2015-01-01

    Clock distribution circuits account for a significant fraction of the power dissipation of the Macro Pixel ASIC (MPA), designed for the pixel layer readout of the so-called Pixel-Strip module in the innermost part of the CMS tracker at the HL-LHC. This work reviews different CMOS circuit architectures envisioned for low power clock distribution in the MPA. Two main topologies will be discussed, based on standard supply voltage and on auxiliary, reduced supply. Circuit performance, in terms of power consumption and speed, is evaluated for each of the proposed solutions and compared with that relevant to standard CMOS drivers.

  19. Designing multiplane computer-generated holograms with consideration of the pixel shape and the illumination wave.

    PubMed

    Kämpfe, Thomas; Kley, Ernst-Bernhard; Tünnermann, Andreas

    2008-07-01

    The majority of image-generating computer-generated holograms (CGHs) are calculated on a discrete numerical grid, whose spacing is defined by the desired pixel size. For single-plane CGHs the influence of the pixel shape and the illumination wave on the actual output distribution is minor and can be treated separately from the numerical calculation. We show that in the case of multiplane CGHs this influence is much more severe. We introduce a new method that takes the pixel shape into account during the design and derive conditions to retain an illumination-wave-independent behavior.

  20. 18k Channels single photon counting readout circuit for hybrid pixel detector

    NASA Astrophysics Data System (ADS)

    Maj, P.; Grybos, P.; Szczygiel, R.; Zoladz, M.; Sakumura, T.; Tsuji, Y.

    2013-01-01

    We have performed measurements of an integrated circuit named PXD18k designed for hybrid pixel semiconductor detectors used in X-ray imaging applications. The PXD18k integrated circuit, fabricated in CMOS 180 nm technology, has dimensions of 9.64 mm×20 mm and contains approximately 26 million transistors. The core of the IC is a matrix of 96×192 pixels with 100 μm×100 μm pixel size. Each pixel works in a single photon counting mode. A single pixel contains two charge sensitive amplifiers with Krummenacher feedback scheme, two shapers, two discriminators (with independent thresholds A and B) and two 16-bit ripple counters. The data are read out via eight low voltage differential signaling (LVDS) outputs with 100 Mbps rate. The power consumption is dominated by analog blocks and it is about 23 μW/pixel. The effective peaking time at the discriminator input is 30 ns and is mainly determined by the time constants of the charge sensitive amplifier (CSA). The gain is equal to 42.5 μV/e- and the equivalent noise charge is 168 e- rms (with bump-bonded silicon pixel detector). Thanks to the use of trim DACs in each pixel, the effective threshold spread at the discriminator input is only 1.79 mV. The dead time of the front end electronics for a standard setting is 172 ns (paralyzable model). In the standard readout mode (when the data collection time is separated from the time necessary to readout data from the chip) the PXD18k IC works with two energy thresholds per pixel. The PXD18k can also be operated in the continuous readout mode (with a zero dead time) where one can select the number of bits readout from each pixel to optimize the PXD18k frame rate. For example, for reading out 16 bits/pixel the frame rate is 2.7 kHz and for 4 bits/pixel it rises to 7.1 kHz.

  1. Overview and present status of the CMS Phase 1 pixel upgrade

    NASA Astrophysics Data System (ADS)

    Lipinski, M.

    2016-07-01

    During Run 2 of the LHC a significant luminosity increase to 2 ×1034cm-2s-1 is foreseen. As the innermost tracking device of CMS, the silicon pixel detector has to cope with large particle fluxes and radiation damage. To maintain the present high tracking efficiency, the current pixel detector will be replaced during an extended winter shutdown in 2016/2017. The design of the new detector is described, with a special focus on the construction and testing of the pixel modules.

  2. Automated procedures for the assembly of the CMS Phase 1 upgrade pixel modules

    NASA Astrophysics Data System (ADS)

    Wade, Alex; CMS Collaboration

    2016-03-01

    The Phase 1 upgrade of the pixel tracker for the CMS experiment requires the assembly of approximately 1000 modules consisting of pixel sensors bump bonded to readout chips. The precision assembly of modules in this volume is made possible using several robotic processes for dispensing epoxy,positioning of sensor components, automatic wire-bonding and robotic deposition of elastomer for wire bond encapsulation. We will describe the these processes in detail, along with the measurements that quanitfy the quality of assembled modules, and describe the subsequent steps in which the sensor modules are used in the construction of the Phase 1 pixel tracker. With support from USCMS.

  3. Design and test of clock distribution circuits for the Macro Pixel ASIC

    NASA Astrophysics Data System (ADS)

    Gaioni, L.; De Canio, F.; Manghisoni, M.; Ratti, L.; Re, V.; Traversi, G.

    2016-07-01

    Clock distribution circuits account for a significant fraction of the power dissipation of the Macro Pixel ASIC (MPA), designed for the pixel layer readout of the so-called Pixel-Strip module in the innermost part of the CMS tracker at the High Luminosity LHC. A test chip including low power clock distribution circuits of the MPA has been designed in a 65 nm CMOS technology and thoroughly tested. This work summarizes the experimental results relevant to the prototype chip, focusing particularly on the power and speed performance and compares such results with those coming from circuit simulations.

  4. ACTIVE-EYES: an adaptive pixel-by-pixel image-segmentation sensor architecture for high-dynamic-range hyperspectral imaging.

    PubMed

    Christensen, Marc P; Euliss, Gary W; McFadden, Michael J; Coyle, Kevin M; Milojkovic, Predrag; Haney, Michael W; van der Gracht, Joeseph; Athale, Ravindra A

    2002-10-10

    The ACTIVE-EYES (adaptive control for thermal imagers via electro-optic elements to yield an enhanced sensor) architecture, an adaptive image-segmentation and processing architecture, based on digital micromirror (DMD) array technology, is described. The concept provides efficient front-end processing of multispectral image data by adaptively segmenting and routing portions of the scene data concurrently to an imager and a spectrometer. The goal is to provide a large reduction in the amount of data required to be sensed in a multispectral imager by means of preprocessing the data to extract the most useful spatial and spectral information during detection. The DMD array provides the flexibility to perform a wide range of spatial and spectral analyses on the scene data. The spatial and spectral processing for different portions of the input scene can be tailored in real time to achieve a variety of preprocessing functions. Since the detected intensity of individual pixels may be controlled, the spatial image can be analyzed with gain varied on a pixel-by-pixel basis to enhance dynamic range. Coarse or fine spectral resolution can be achieved in the spectrometer by use of dynamically controllable or addressable dispersion elements. An experimental prototype, which demonstrated the segmentation between an imager and a grating spectrometer, was demonstrated and shown to achieve programmable pixelated intensity control. An information theoretic analysis of the dynamic-range control aspect was conducted to predict the performance enhancements that might be achieved with this architecture. The results indicate that, with a properly configured algorithm, the concept achieves the greatest relative information recovery from a detected image when the scene is made up of a relatively large area of moderate-dynamic-range pixels and a relatively smaller area of strong pixels that would tend to saturate a conventional sensor. PMID:12389978

  5. Improving Kepler Pipeline Sensitivity with Pixel Response Function Photometry.

    NASA Astrophysics Data System (ADS)

    Morris, Robert L.; Bryson, Steve; Jenkins, Jon Michael; Smith, Jeffrey C

    2014-06-01

    We present the results of our investigation into the feasibility and expected benefits of implementing PRF-fitting photometry in the Kepler Science Processing Pipeline. The Kepler Pixel Response Function (PRF) describes the expected system response to a point source at infinity and includes the effects of the optical point spread function, the CCD detector responsivity function, and spacecraft pointing jitter. Planet detection in the Kepler pipeline is currently based on simple aperture photometry (SAP), which is most effective when applied to uncrowded bright stars. Its effectiveness diminishes rapidly as target brightness decreases relative to the effects of noise sources such as detector electronics, background stars, and image motion. In contrast, PRF photometry is based on fitting an explicit model of image formation to the data and naturally accounts for image motion and contributions of background stars. The key to obtaining high-quality photometry from PRF fitting is a high-quality model of the system's PRF, while the key to efficiently processing the large number of Kepler targets is an accurate catalog and accurate mapping of celestial coordinates onto the focal plane. If the CCD coordinates of stellar centroids are known a priori then the problem of PRF fitting becomes linear. A model of the Kepler PRF was constructed at the time of spacecraft commissioning by fitting piecewise polynomial surfaces to data from dithered full frame images. While this model accurately captured the initial state of the system, the PRF has evolved dynamically since then and has been seen to deviate significantly from the initial (static) model. We construct a dynamic PRF model which is then used to recover photometry for all targets of interest. Both simulation tests and results from Kepler flight data demonstrate the effectiveness of our approach. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA’s Science

  6. Non-linear pixels in the USNO Tektronix 2048 X 2048 CCD

    NASA Astrophysics Data System (ADS)

    Levison, Harold F.

    Approximately 4.4 percent of the pixels on the USNO Tektronix 2048 x 2048 CCD are nonlinear. These nonlinearities can be fit by analytic functions in two regimes. When I(exp) is less than about 400 ADU, the bad pixels are fit by I(obs)/I(exp) = 1 - fe exp gIobs. For I(exp) of more than about 600 ADU, I(exp) = aI(obs) exp b is used. Unfortunately, it was not possible to find an analytic function that fit all pixels between these two regimes. since the CCD must be preflashed to remove charge transfer inefficiencies, it is only necessary to fit the nonlinearities at high charge levels. Using the second fitting function, it was possible to correct 93 percent of the bad pixels over approximately 2 orders of magnitude in the illumination.

  7. Compact all-CMOS spatiotemporal compressive sensing video camera with pixel-wise coded exposure.

    PubMed

    Zhang, Jie; Xiong, Tao; Tran, Trac; Chin, Sang; Etienne-Cummings, Ralph

    2016-04-18

    We present a low power all-CMOS implementation of temporal compressive sensing with pixel-wise coded exposure. This image sensor can increase video pixel resolution and frame rate simultaneously while reducing data readout speed. Compared to previous architectures, this system modulates pixel exposure at the individual photo-diode electronically without external optical components. Thus, the system provides reduction in size and power compare to previous optics based implementations. The prototype image sensor (127 × 90 pixels) can reconstruct 100 fps videos from coded images sampled at 5 fps. With 20× reduction in readout speed, our CMOS image sensor only consumes 14μW to provide 100 fps videos. PMID:27137331

  8. Characterization of M-π-n CdTe pixel detectors coupled to HEXITEC readout chip

    NASA Astrophysics Data System (ADS)

    Veale, M. C.; Kalliopuska, J.; Pohjonen, H.; Andersson, H.; Nenonen, S.; Seller, P.; Wilson, M. D.

    2012-01-01

    Segmentation of the anode-side of an M-π-n CdTe diode, where the pn-junction is diffused into the detector bulk, produces large improvements in the spatial and energy resolution of CdTe pixel detectors. It has been shown that this fabrication technique produces very high inter-pixel resistance and low leakage currents are obtained by physical isolation of the pixels of M-π-n CdTe detectors. In this paper the results from M-π-n CdTe detectors stud bonded to a spectroscopic readout ASIC are reported. The CdTe pixel detectors have 250 μm pitch and an area of 5 × 5 mm2 with thicknesses of 1 and 2 mm. The polarization and energy resolution dependence of the M-π-n CdTe detectors as a function of detector thickness are discussed.

  9. Performance of silicon pixel detectors at small track incidence angles for the ATLAS Inner Tracker upgrade

    NASA Astrophysics Data System (ADS)

    Viel, Simon; Banerjee, Swagato; Brandt, Gerhard; Carney, Rebecca; Garcia-Sciveres, Maurice; Hard, Andrew Straiton; Kaplan, Laser Seymour; Kashif, Lashkar; Pranko, Aliaksandr; Rieger, Julia; Wolf, Julian; Wu, Sau Lan; Yang, Hongtao

    2016-09-01

    In order to enable the ATLAS experiment to successfully track charged particles produced in high-energy collisions at the High-Luminosity Large Hadron Collider, the current ATLAS Inner Detector will be replaced by the Inner Tracker (ITk), entirely composed of silicon pixel and strip detectors. An extension of the tracking coverage of the ITk to very forward pseudorapidity values is proposed, using pixel modules placed in a long cylindrical layer around the beam pipe. The measurement of long pixel clusters, detected when charged particles cross the silicon sensor at small incidence angles, has potential to significantly improve the tracking efficiency, fake track rejection, and resolution of the ITk in the very forward region. The performance of state-of-the-art pixel modules at small track incidence angles is studied using test beam data collected at SLAC and CERN.

  10. Smart-pixel spatial light modulator for incorporation in an optoelectronic neural network.

    PubMed

    Bar-Tana, I; Sharpe, J P; McKnight, D J; Johnson, K M

    1995-02-01

    We present the design, fabrication, and testing of a novel liquid-crystal-on-silicon optically addressed spatial light modulator for use as a weight matrix in an ART-1 optoelectronic neural processor. Each pixel in the 50 x 83 element array occupies 75 microm x 75 microm and consists of a photodetector, a threshold circuit, a 1-bit (flip-flop) memory element, and a liquid-crystal modulating mirror. The array is designed to switch all the pixels initially to the ON state. Subsequently each pixel is independently switched to the OFF state if a superthreshold amount of light falls upon the pixel's photodetector. The device has a contrast ratio of 20:1, a switch-on time (10-90% rise time) of 500 micros, and a switch-off time of ~500 micros (depending on the externally set threshold). Measured device uniformities and interpixel coupling are also described. PMID:19859168

  11. Pixel detectors in double beta decay experiments, a new approach for background reduction

    SciTech Connect

    Jose, J. M.; Čermák, P.; Štekl, I.; Rukhadze, E. N.; Rukhadze, N. I.; Brudanin, V. B.; Fiederle, M.; Fauler, A.; Loaiza, P.

    2013-08-08

    Double beta decay (ββ) experiments are challenging frontiers in contemporary physics. These experiments have the potential to investigate more about neutrinos (eg. nature and mass). The main challenge for these experiments is the reduction of background. The group at IEAP, CTU in Prague is investigating a new approach using pixel detectors Timepix. Pixel detector offer background reduction capabilities with its ability to identify the particle interaction (from the 2D signature it generates). However, use of pixel detectors has some challenges such as the presence of readout electronics near the sensing medium and heat dissipation. Different aspects of pixel setup (identification of radio-impurities, selection of radio-pure materials) and proposed experimental setup are presented. Also, results of preliminary background measurements (performed on the surface and in the underground laboratories) using the prototype setups are presented.

  12. 4.3 μm quantum cascade detector in pixel configuration.

    PubMed

    Harrer, A; Schwarz, B; Schuler, S; Reininger, P; Wirthmüller, A; Detz, H; MacFarland, D; Zederbauer, T; Andrews, A M; Rothermund, M; Oppermann, H; Schrenk, W; Strasser, G

    2016-07-25

    We present the design simulation and characterization of a quantum cascade detector operating at 4.3μm wavelength. Array integration and packaging processes were investigated. The device operates in the 4.3μm CO2 absorption region and consists of 64 pixels. The detector is designed fully compatible to standard processing and material growth methods for scalability to large pixel counts. The detector design is optimized for a high device resistance at elevated temperatures. A QCD simulation model was enhanced for resistance and responsivity optimization. The substrate illuminated pixels utilize a two dimensional Au diffraction grating to couple the light to the active region. A single pixel responsivity of 16mA/W at room temperature with a specific detectivity D* of 5⋅107 cmHz/W was measured. PMID:27464155

  13. Plasmonic cavity-apertures as dynamic pixels for the simultaneous control of colour and intensity

    PubMed Central

    Yun, Hansik; Lee, Seung-Yeol; Hong, Keehoon; Yeom, Jiwoon; Lee, Byoungho

    2015-01-01

    Despite steady technological progress, displays are still subject to inherent limitations in resolution improvement and pixel miniaturization because a series of colours is generally expressed by a combination of at least three primary colour pixels. Here we propose a structure comprising a metal cavity and a nanoaperture, which we refer to as a cavity-aperture, to simultaneously control the colour and intensity of transmitted light in a single pixel. The metal cavity constructs plasmonic standing waves to organize the spatial distribution of amplitudes according to wavelength, and the nanoaperture permits light with a specific wavelength and amplitude to pass through it, depending on the nanoaperature's relative position in the cavity and the polarization state of the incident light. Therefore, the cavity-aperture has the potential to function as a dynamic colour pixel. This design method may be helpful in developing various photonic devices, such as micro-imaging systems and multiplexed sensors. PMID:25990071

  14. The FE-I4 Pixel Readout Chip and the IBL Module

    SciTech Connect

    Barbero, Marlon; Arutinov, David; Backhaus, Malte; Fang, Xiao-Chao; Gonella, Laura; Hemperek, Tomasz; Karagounis, Michael; Hans, Kruger; Kruth, Andre; Wermes, Norbert; Breugnon, Patrick; Fougeron, Denis; Gensolen, Fabrice; Menouni, Mohsine; Rozanov, Alexander; Beccherle, Roberto; Darbo, Giovanni; Caminada, Lea; Dube, Sourabh; Fleury, Julien; Gnani, Dario; /LBL, Berkeley /NIKHEF, Amsterdam /Gottingen U. /SLAC

    2012-05-01

    FE-I4 is the new ATLAS pixel readout chip for the upgraded ATLAS pixel detector. Designed in a CMOS 130 nm feature size process, the IC is able to withstand higher radiation levels compared to the present generation of ATLAS pixel Front-End FE-I3, and can also cope with higher hit rate. It is thus suitable for intermediate radii pixel detector layers in the High Luminosity LHC environment, but also for the inserted layer at 3.3 cm known as the 'Insertable B-Layer' project (IBL), at a shorter timescale. In this paper, an introduction to the FE-I4 will be given, focusing on test results from the first full size FE-I4A prototype which has been available since fall 2010. The IBL project will be introduced, with particular emphasis on the FE-I4-based module concept.

  15. The DC-DC conversion power system of the CMS Phase-1 pixel upgrade

    NASA Astrophysics Data System (ADS)

    Feld, L.; Karpinski, W.; Klein, K.; Lipinski, M.; Preuten, M.; Rauch, M.; Schmitz, St.; Wlochal, M.

    2015-01-01

    The pixel detector of the CMS experiment will be exchanged during the year-end technical stop in 2016/2017, as part of the experiment's Phase-1 upgrade. The new device will feature approximately twice the number of readout channels, and consequently the power consumption will be doubled. By moving to a DC-DC conversion powering scheme, it is possible to power the new pixel detector with the existing power supplies and cable plant. The power system of the Phase-1 pixel detector is described and the performance of the new components, including DC-DC converters, DC-DC converter motherboards and various power distribution boards, is detailed. The outcome of system tests in terms of electrical behaviour, thermal management and pixel module performance is discussed.

  16. Charge Sharing and Charge Loss in a Cadmium-Zinc-Telluride Fine-Pixel Detector Array

    NASA Technical Reports Server (NTRS)

    Gaskin, J. A.; Sharma, D. P.; Ramsey, B. D.; Six, N. Frank (Technical Monitor)

    2002-01-01

    Because of its high atomic number, room temperature operation, low noise, and high spatial resolution a Cadmium-Zinc-Telluride (CZT) multi-pixel detector is ideal for hard x-ray astrophysical observation. As part of on-going research at MSFC (Marshall Space Flight Center) to develop multi-pixel CdZnTe detectors for this purpose, we have measured charge sharing and charge loss for a 4x4 (750micron pitch), lmm thick pixel array and modeled these results using a Monte-Carlo simulation. This model was then used to predict the amount of charge sharing for a much finer pixel array (with a 300micron pitch). Future work will enable us to compare the simulated results for the finer array to measured values.

  17. ASICs in nanometer and 3D technologies for readout of hybrid pixel detectors

    NASA Astrophysics Data System (ADS)

    Maj, Piotr; Grybos, Pawel; Kmon, Piotr; Szczygiel, Robert

    2013-07-01

    Hybrid pixel detectors working in a single photon counting mode are very attractive solutions for material science and medical X-ray imaging applications. Readout electronics of these detectors has to match the geometry of pixel detectors with an area of readout channel of 100 μm × 100 μm (or even less) and very small power consumption (a few tens of μW). New solutions of readout ASICs are going into directions of better spatial resolutions, higher data throughput and more advanced functionality. We report on the design and measurement results of two pixel prototype ASICs in nanometer technology and 3D technology which offer fast signal processing, low noise performance and advanced functionality per single readout pixel cell.

  18. Large Area Crop Inventory Experiment (LACIE). The boundary pixel study in Kansas and North Dakota

    NASA Technical Reports Server (NTRS)

    Register, D. T. (Principal Investigator); Ona, A. L.

    1979-01-01

    The author has identified the following significant results. The statistical mapping approach to handling boundary pixels can be used as a standard for objectively comparing the cluster based technique, the maximum likelihood estimate based technique, and multicategory labeling.

  19. Si pixel detectors in the detection of EC/EC decay

    SciTech Connect

    Jose, J. M.; Čermák, P.; Fajt, L.; Štekl, I.; Rukhadze, N. I.; Shitov, Yu. A.

    2015-08-17

    The SPT collaboration has been investigating the applicability of pixel detectors in the detection of two neutrino double electron capture (2νEC/EC) in{sup 106}Cd. The collaboration has proposed a Silicon Pixel Telescope (SPT) where a pair of Si pixel detectors with enriched Cd foil in the middle forms the detection unit. The Pixel detector gives spatial information along with energy of the particle, thus helps to identify and remove the background signals. Four units of SPT prototype (using 0.5 and 1 mm Si sensors) were fabricated and installed in the LSM underground laboratory, France. Recent progress in the SPT experiment and preliminary results from background measurements are presented.

  20. Assembly procedure for the silicon pixel ladder for PHENIX silicon vertex tracker.

    SciTech Connect

    Onuki, Y.; PHENIX Collaboration, et al.

    2009-05-08

    The silicon vertex tracker (VTX) will be installed in the summer of 2010 to enhance the physics capabilities of the Pioneering High Energy Nuclear Interaction eXperiment (PHENIX) experiment at Brookhaven National Laboratory. The VTX consists of two types of silicon detectors: a pixel detector and a strip detector. The pixel detector consists of 30 pixel ladders placed on the two inner cylindrical layers of the VTX. The ladders are required to be assembled with high precision, however, they should be assembled in both cost and time efficient manner. We have developed an assembly bench for the ladder with several assembly fixtures and a quality assurance (Q/A) system using a 3D measurement machine. We have also developed an assembly procedure for the ladder, including a method for dispensing adhesive uniformly and encapsulation of bonding wires. The developed procedures were adopted in the assembly of the first pixel ladder and satisfy the requirements.