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Sample records for large focal plane

  1. Large Format Uncooled Focal Plane Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Black Forest Engineering has identified innovative modifications in uncooled focal plane array (UFPA) architecture and processing that allows development of large...

  2. Large Format Uncooled Focal Plane Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Uncooled focal plane arrays have improved dramatically and array sizes of 320x240 elements in a 50-?m pitch are commercially available at affordable cost. Black...

  3. Design of large aperture focal plane shutter

    Science.gov (United States)

    Hu, Jia-wen; Ma, Wen-li; Huang, Jin-long

    2012-09-01

    To satisfy the requirement of large telescope, a large aperture focal plane shutter with aperture size of φ200mm was researched and designed to realize, which could be started and stopped in a relative short time with precise position, and also the blades could open and close at the same time at any orientation. Timing-belts and stepper motors were adopted as the drive mechanism. Velocity and position of the stepper motors were controlled by the PWM pulse generated by DSP. Exponential curve is applied to control the velocity of the stepper motors to make the shutter start and stop in a short time. The closing/open time of shutter is 0.2s, which meets the performance requirements of large telescope properly.

  4. Innovative focal plane design for large space telescopes

    Science.gov (United States)

    Jahn, Wilfried; Ferrari, Marc; Hugot, Emmanuel

    2016-07-01

    Future large drift-scan space telescopes, providing high angular resolution and sensitive observations, require long linear focal planes covering large fields of view. In order to reach higher on-earth spatial resolution while keeping a large field of view, the use of homothetic imaging systems is prohibitive for VIS/IR applications. Based on Integral Field Unit technology developed for ground based instrumentation, we present an innovative optical system reorganizing a 1D field of view on a 2D detector array. Such a solution presents a high gain in terms of volume and weight, allowing compact cryogenic systems for IR observations.

  5. Cosmology Large Angular Scale Surveyor (CLASS) Focal Plane Development

    CERN Document Server

    Chuss, D T; Amiri, M; Appel, J; Bennett, C L; Colazo, F; Denis, K L; Dünner, R; Essinger-Hileman, T; Eimer, J; Fluxa, P; Gothe, D; Halpern, M; Harrington, K; Hilton, G; Hinshaw, G; Hubmayr, J; Iuliano, J; Marriage, T A; Miller, N; Moseley, S H; Mumby, G; Petroff, M; Reintsema, C; Rostem, K; U-Yen, K; Watts, D; Wagner, E; Wollack, E J; Xu, Z; Zeng, L

    2015-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization of the Cosmic Microwave Background to search for and characterize the polarized signature of inflation. CLASS will operate from the Atacama Desert and observe $\\sim$70% of the sky. A variable-delay polarization modulator (VPM) modulates the polarization at $\\sim$10 Hz to suppress the 1/f noise of the atmosphere and enable the measurement of the large angular scale polarization modes. The measurement of the inflationary signal across angular scales that span both the recombination and reionization features allows a test of the predicted shape of the polarized angular power spectra in addition to a measurement of the energy scale of inflation. CLASS is an array of telescopes covering frequencies of 38, 93, 148, and 217 GHz. These frequencies straddle the foreground minimum and thus allow the extraction of foregrounds from the primordial signal. Each focal plane contains feedhorn-coupled transition-edge sensors that simultaneously d...

  6. Cosmology Large Angular Scale Surveyor (CLASS) Focal Plane Development

    Science.gov (United States)

    Chuss, D. T.; Ali, A.; Amiri, M.; Appel, J.; Bennett, C. L.; Colazo, F.; Denis, K. L.; Dunner, R.; Essinger-Hileman, T.; Eimer, J.; Fluxa, P.; Gothe, D.; Halpern, M.; Harrington, K.; Hilton, G.; Hinshaw, G.; Hubmayr, J.; Iuliano, J.; Marriage, T. A.; Miller, N.; Moseley, S. H.; Mumby, G.; Petroff, M.; Reintsema, C.; Rostem, K.; U-yen, K.; Watts, D.; Wagner, E.; Wollack, E. J.; Xu, Z.; Zeng, L.

    2015-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization of the Cosmic Microwave Background to search for and characterize the polarized signature of inflation. CLASS will operate from the Atacama Desert and observe approx.70% of the sky. A variable-delay polarization modulator provides modulation of the polarization at approx.10Hz to suppress the 1/f noise of the atmosphere and enable the measurement of the large angular scale polarization modes. The measurement of the inflationary signal across angular scales that spans both the recombination and reionization features allows a test of the predicted shape of the polarized angular power spectra in addition to a measurement of the energy scale of inflation. CLASS is an array of telescopes covering frequencies of 38, 93, 148, and 217 GHz. These frequencies straddle the foreground minimum and thus allow the extraction of foregrounds from the primordial signal. Each focal plane contains feedhorn-coupled transition-edge sensors that simultaneously detect two orthogonal linear polarizations. The use of single-crystal silicon as the dielectric for the on-chip transmission lines enables both high efficiency and uniformity in fabrication. Integrated band definition has been implemented that both controls the bandpass of the single-mode transmission on the chip and prevents stray light from coupling to the detectors.

  7. Cosmology Large Angular Scale Surveyor (CLASS) Focal Plane Development

    Science.gov (United States)

    Chuss, D. T.; Ali, A.; Amiri, M.; Appel, J.; Bennett, C. L.; Colazo, F.; Denis, K. L.; Dünner, R.; Essinger-Hileman, T.; Eimer, J.; Fluxa, P.; Gothe, D.; Halpern, M.; Harrington, K.; Hilton, G.; Hinshaw, G.; Hubmayr, J.; Iuliano, J.; Marriage, T. A.; Miller, N.; Moseley, S. H.; Mumby, G.; Petroff, M.; Reintsema, C.; Rostem, K.; U-Yen, K.; Watts, D.; Wagner, E.; Wollack, E. J.; Xu, Z.; Zeng, L.

    2016-08-01

    The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization of the Cosmic Microwave Background to search for and characterize the polarized signature of inflation. CLASS will operate from the Atacama Desert and observe ˜ 70 % of the sky. A variable-delay polarization modulator provides modulation of the polarization at ˜ 10 Hz to suppress the 1/ f noise of the atmosphere and enable the measurement of the large angular scale polarization modes. The measurement of the inflationary signal across angular scales that spans both the recombination and reionization features allows a test of the predicted shape of the polarized angular power spectra in addition to a measurement of the energy scale of inflation. CLASS is an array of telescopes covering frequencies of 38, 93, 148, and 217 GHz. These frequencies straddle the foreground minimum and thus allow the extraction of foregrounds from the primordial signal. Each focal plane contains feedhorn-coupled transition-edge sensors that simultaneously detect two orthogonal linear polarizations. The use of single-crystal silicon as the dielectric for the on-chip transmission lines enables both high efficiency and uniformity in fabrication. Integrated band definition has been implemented that both controls the bandpass of the single-mode transmission on the chip and prevents stray light from coupling to the detectors.

  8. Large-format and multispectral QWIP infrared focal plane arrays

    Science.gov (United States)

    Goldberg, Arnold C.; Choi, Kwong-Kit; Jhabvala, Murzy; La, Anh; Uppal, Parvez N.; Winn, Michael L.

    2003-09-01

    The next generation of infrared (IR) focal plane arrays (FPAs) will need to be a significant improvement in capability over those used in present-day second generation FLIRs. The Army's Future Combat System requires that the range for target identification be greater than the range of detection for an opposing sensor. To accomplish this mission, the number of pixels on the target must be considerably larger than that possible with 2nd generation FLIR. Therefore, the 3rd generation FLIR will need to be a large format staring FPA with more than 1000 pixels on each side. In addition, a multi-spectral capability will be required to allow operability in challenging ambient environments, discriminate targets from decoys, and to take advantage of the smaller diffraction blur in the MWIR for enhanced image resolution. We report on laboratory measurements of a large format (1024 x 1024 pixels) single-color LWIR IR FPA made using the corrugated quantum well infrared photodetector (QWIP) structure by the ARL/NASA team. The pixel pitch is 18 μm and the spectral response peaks at 8.8 μm with a 9.2 μm cutoff. We report on recent results using a MWIR/LWIR QWIP FPA to image the boost phase of a launch vehicle for missile defense applications and a LWIR/LWIR FPA designed specifically for detecting the disturbed soil associated with buried land mines. Finally, we report on the fabrication of a new read-out integrated circuit (ROIC) specifically designed for multi-spectral operation.

  9. Large format focal plane array integration with precision alignment, metrology and accuracy capabilities

    Science.gov (United States)

    Neumann, Jay; Parlato, Russell; Tracy, Gregory; Randolph, Max

    2015-09-01

    Focal plane alignment for large format arrays and faster optical systems require enhanced precision methodology and stability over temperature. The increase in focal plane array size continues to drive the alignment capability. Depending on the optical system, the focal plane flatness of less than 25μm (.001") is required over transition temperatures from ambient to cooled operating temperatures. The focal plane flatness requirement must also be maintained in airborne or launch vibration environments. This paper addresses the challenge of the detector integration into the focal plane module and housing assemblies, the methodology to reduce error terms during integration and the evaluation of thermal effects. The driving factors influencing the alignment accuracy include: datum transfers, material effects over temperature, alignment stability over test, adjustment precision and traceability to NIST standard. The FPA module design and alignment methodology reduces the error terms by minimizing the measurement transfers to the housing. In the design, the proper material selection requires matched coefficient of expansion materials minimizes both the physical shift over temperature as well as lowering the stress induced into the detector. When required, the co-registration of focal planes and filters can achieve submicron relative positioning by applying precision equipment, interferometry and piezoelectric positioning stages. All measurements and characterizations maintain traceability to NIST standards. The metrology characterizes the equipment's accuracy, repeatability and precision of the measurements.

  10. Measuring the Flatness of Focal Plane for Very Large Mosaic CCD Camera

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Jiangang; Estrada, Juan; Cease, Herman; Diehl, H.Thomas; Flaugher, Brenna L.; Kubik, Donna; Kuk, Keivin; Kuropatkine, Nickolai; Lin, Huan; Montes, Jorge; Scarpine, Vic; /Fermilab

    2010-06-08

    Large mosaic multiCCD camera is the key instrument for modern digital sky survey. DECam is an extremely red sensitive 520 Megapixel camera designed for the incoming Dark Energy Survey (DES). It is consist of sixty two 4k x 2k and twelve 2k x 2k 250-micron thick fully-depleted CCDs, with a focal plane of 44 cm in diameter and a field of view of 2.2 square degree. It will be attached to the Blanco 4-meter telescope at CTIO. The DES will cover 5000 square-degrees of the southern galactic cap in 5 color bands (g, r, i, z, Y) in 5 years starting from 2011. To achieve the science goal of constraining the Dark Energy evolution, stringent requirements are laid down for the design of DECam. Among them, the flatness of the focal plane needs to be controlled within a 60-micron envelope in order to achieve the specified PSF variation limit. It is very challenging to measure the flatness of the focal plane to such precision when it is placed in a high vacuum dewar at 173 K. We developed two image based techniques to measure the flatness of the focal plane. By imaging a regular grid of dots on the focal plane, the CCD offset along the optical axis is converted to the variation the grid spacings at different positions on the focal plane. After extracting the patterns and comparing the change in spacings, we can measure the flatness to high precision. In method 1, the regular dots are kept in high sub micron precision and cover the whole focal plane. In method 2, no high precision for the grid is required. Instead, we use a precise XY stage moves the pattern across the whole focal plane and comparing the variations of the spacing when it is imaged by different CCDs. Simulation and real measurements show that the two methods work very well for our purpose, and are in good agreement with the direct optical measurements.

  11. Beamlet focal plane diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Caird, J.A.; Nielsen, N.D.; Patton, H.G.; Seppala, L.G.; Thompson, C.E.; Wegner, P.J.

    1996-12-01

    This paper describes the major optical and mechanical design features of the Beamlet Focal Plane Diagnostic system as well as measurements of the system performance, and typical data obtained to date. We also discuss the NIF requirements on the focal spot that we are interested in measuring, and some of our plans for future work using this system.

  12. SNAP focal plane

    Energy Technology Data Exchange (ETDEWEB)

    Lampton, Michael L.; Kim, A.; Akerlof, C.W.; Aldering, G.; Amanullah, R.; Astier, P.; Barrelet, E.; Bebek, C.; Bergstrom, L.; Berkovitz, J.; Bernstein, G.; Bester, M.; Bonissent, A.; Bower, C.; Carithers Jr., W.C.; Commins, E.D.; Day, C.; Deustua, S.E.; DiGennaro,R.; Ealet, A.; Ellis, R.S.; Eriksson, M.; Fruchter, A.; Genat, J.-F.; Goldhaber, G.; Goobar, A.; Groom, D.; Harris, S.E.; Harvey, P.R.; Heetderks, H.D.; Holland, S.E.; Huterer, D.; Karcher, A.; Kolbe, W.; Krieger, B.; Lafever, R.; Lamoureux, J.; Levi, M.E.; Levin, D.S.; Linder,E.V.; Loken, S.C.; Malina, R.; Massey, R.; McKay, T.; McKee, S.P.; Miquel, R.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Nugent, P.; Oluseyi, H.; Pain, R.; Palaio, N.; Pankow, D.; Perlmutter, S.; Pratt, R.; Prieto, E.; Refregier, A.; Rhodes, J.; Robinson, K.; Roe, N.; Sholl, M.; Schubnell, M.; Smadja, G.; Smoot, G.; Spadafora, A.; Tarle, G.; Tomasch,A.; von der Lippe, H.; Vincent, R.; Walder, J.-P.; Wang, G.

    2002-07-29

    The proposed SuperNova/Acceleration Probe (SNAP) mission will have a two-meter class telescope delivering diffraction-limited images to an instrumented 0.7 square-degree field sensitive in the visible and near-infrared wavelength regime. We describe the requirements for the instrument suite and the evolution of the focal plane design to the present concept in which all the instrumentation--visible and near-infrared imagers, spectrograph, and star guiders--share one common focal plane.

  13. SNAP Satellite Focal Plane Development

    Energy Technology Data Exchange (ETDEWEB)

    Bebek, C.; Akerlof, C.; Aldering, G.; Amanullah, R.; Astier, P.; Baltay, C.; Barrelet, E.; Basa, S.; Bercovitz, J.; Bergstrom, L.; Berstein, G.P.; Bester, M.; Bohlin, R.; Bonissent, A.; Bower, C.; Campbell, M.; Carithers, W.; Commins, E.; Day, C.; Deustua, S.; DiGennaro, R.; Ealet, A.; Ellis, R.; Emmett, W.; Eriksson, M.; Fouchez,D.; Fruchter, A.; Genat, J-F.; Goldhaber, G.; Goobar, A.; Groom, D.; Heetderks, H.; Holland, S.; Huterer, D.; Johnson, W.; Kadel, R.; Karcher,A.; Kim, A.; Kolbe, W.; Lafever, R.; Lamoureaux, J.; Lampton, M.; Lefevre, O.; Levi, M.; Levin, D.; Linder, E.; Loken, S.; Malina, R.; Mazure, A.; McKay, T.; McKee, S.; Miquel, R.; Morgan, N.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Roe, N.; Nugent, P.; Oluseyi, H.; Pain, R.; Palaio, N.; Pankow, D.; Perlmutter, S.; Prieto, E.; Rabinowitz,D.; Refregier, A.; Rhodes, J.; Schubnell, M.; Sholl, M.; Smadja, G.; Smith, R.; Smoot, G.; Snyder, J.; Spadafora, A.; Szymkowiak, A.; Tarle,G.; Taylor, K.; Tilquin, A.; Tomasch, A.; Vincent, D.; von der Lippe, H.; Walder, J-P.; Wang, G.

    2003-07-07

    The proposed SuperNova/Acceleration Probe (SNAP) mission will have a two-meter class telescope delivering diffraction-limited images to an instrumented 0.7 square degree field in the visible and near-infrared wavelength regime. The requirements for the instrument suite and the present configuration of the focal plane concept are presented. A two year R&D phase, largely supported by the Department of Energy, is just beginning. We describe the development activities that are taking place to advance our preparedness for mission proposal in the areas of detectors and electronics.

  14. Low-Noise, UV-to-SWIR Broadband Photodiodes for Large-Format Focal Plane Array Sensors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Broadband focal plane arrays, operating in UV-to-SWIR wavelength range, are required for atmospheric monitoring of greenhouse gases. Currently, separate image...

  15. Low-Noise, UV-to-SWIR Broadband Photodiodes for Large-Format Focal Plane Array Sensors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Broadband focal plane arrays, operating in UV-to-SWIR wavelength range, are required for atmospheric monitoring of greenhouse gases. Currently, separate image...

  16. Infrared microspectroscopic imaging using a large radius germanium internal reflection element and a focal plane array detector.

    Science.gov (United States)

    Patterson, Brian M; Havrilla, George J; Marcott, Curtis; Story, Gloria M

    2007-11-01

    Previously, we established the ability to collect infrared microspectroscopic images of large areas using a large radius hemisphere internal reflection element (IRE) with both a single point and a linear array detector. In this paper, preliminary work in applying this same method to a focal plane array (FPA) infrared imaging system is demonstrated. Mosaic tile imaging using a large radius germanium hemispherical IRE on a FPA Fourier transform infrared microscope imaging system can be used to image samples nearly 1.5 mm x 2 mm in size. A polymer film with a metal mask is imaged using this method for comparison to previous work. Images of hair and skin samples are presented, highlighting the complexity of this method. Comparisons are made between the linear array and FPA methods.

  17. RF/Optical Demonstration: Focal Plane Assembly

    Science.gov (United States)

    Hoppe, D. J.; Chung, S.; Kovalik, J.; Gama, E.; Fernandez, M. M.

    2016-11-01

    In this article, we describe the second-generation focal plane optical assembly employed in the RF/optical demonstration at DSS-13. This assembly receives reflected light from the two mirror segments mounted on the RF primary. The focal plane assembly contains a fast steering mirror (FSM) to stabilize the focal plane spot, a pupil camera to aid in aligning the two segments, and several additional cameras for receiving the optical signal prior to as well as after the FSM loop.

  18. Very large scale heterogeneous integration (VLSHI) and wafer-level vacuum packaging for infrared bolometer focal plane arrays

    Science.gov (United States)

    Forsberg, Fredrik; Roxhed, Niclas; Fischer, Andreas C.; Samel, Björn; Ericsson, Per; Hoivik, Nils; Lapadatu, Adriana; Bring, Martin; Kittilsland, Gjermund; Stemme, Göran; Niklaus, Frank

    2013-09-01

    Imaging in the long wavelength infrared (LWIR) range from 8 to 14 μm is an extremely useful tool for non-contact measurement and imaging of temperature in many industrial, automotive and security applications. However, the cost of the infrared (IR) imaging components has to be significantly reduced to make IR imaging a viable technology for many cost-sensitive applications. This paper demonstrates new and improved fabrication and packaging technologies for next-generation IR imaging detectors based on uncooled IR bolometer focal plane arrays. The proposed technologies include very large scale heterogeneous integration for combining high-performance, SiGe quantum-well bolometers with electronic integrated read-out circuits and CMOS compatible wafer-level vacuum packing. The fabrication and characterization of bolometers with a pitch of 25 μm × 25 μm that are arranged on read-out-wafers in arrays with 320 × 240 pixels are presented. The bolometers contain a multi-layer quantum well SiGe thermistor with a temperature coefficient of resistance of -3.0%/K. The proposed CMOS compatible wafer-level vacuum packaging technology uses Cu-Sn solid-liquid interdiffusion (SLID) bonding. The presented technologies are suitable for implementation in cost-efficient fabless business models with the potential to bring about the cost reduction needed to enable low-cost IR imaging products for industrial, security and automotive applications.

  19. Mosaic of spatial large scale CMOS focal plane array%空间大规模CMOS面阵焦平面拼接技术

    Institute of Scientific and Technical Information of China (English)

    雍朝良; 林剑春; 赵明; 陈凡胜

    2012-01-01

    为了提高空间遥感器的时间分辨率,采用更大规模的红外焦平面阵列和可见焦平面阵列是未来高时间分辨率空间遥感的发展趋势.目前,由于大规模阵列探测器受到CMOS工艺的限制,不能满足空间高时间分辨率发展的要求.为了满足大规模焦平面遥感应用的要求,提出了一种大规模阵列焦平面机械的拼接方法.该方法采用精密压电陶瓷电机,完成探测器焦平面的微米量级位置调整,并通过激光测距仪测量以及计算机平面拟合来确定探测器焦平面的空间位置,进而实现了大规模非连续CMOS焦平面阵列的机械式拼接.%In order to improve the time resolution of space remote sensor, using more large -scale infrared focal plane array and visible focal plane array are the future trend of the high time resolution space remote sensing. By now, the scale of the massive array detector is limited by the CMOS technology, thus it is unable to meet the requirements of the development of the space high time resolution detect. In order to meet the needs of large focal plane remote sensing application a novel method of assembling the large scale FPA (Focal Plane Array)was presnted. The precision piezoelectric ceramic motor was used to complete the position adjustment of focal plane of the detector in micrometer. Laser range finder measurement and computer plane fitting were used to determine the spatial position of the detector focal plane, thereby large-scale non-continuous mechanical splicing of the CMOS focal plane array was achieved.

  20. Focal Plane Instrumentation of VERITAS

    CERN Document Server

    Nagai, T; Sleege, G; Petry, D

    2007-01-01

    VERITAS is a new atmospheric Cherenkov imaging telescope array to detect very high energy gamma rays above 100 GeV. The array is located in southern Arizona, USA, at an altitude of 1268m above sea level. The array consists of four 12-m telescopes of Davies-Cotton design and structurally resembling the Whipple 10-m telescope. The four focal plane instruments are equipped with high-resolution (499 pixels) fast photo-multiplier-tube (PMT) cameras covering a 3.5 degree field of view with 0.15 degree pixel separation. Light concentrators reduce the dead-space between PMTs to 25% and shield the PMTs from ambient light. The PMTs are connected to high-speed preamplifiers allowing operation at modest anode current and giving good single photoelectron peaks in situ. Electronics in the focus box provides real-time monitoring of the anode currents for each pixel and ambient environmental conditions. A charge injection subsystem installed in the focus box allows daytime testing of the trigger and data acquisition system b...

  1. Smart focal plane technologies for ELT instruments

    Science.gov (United States)

    Cunningham, Colin R.; Ramsay-Howat, Suzanne K.; Garzon, Francisco; Parry, Ian R.; Prieto, Eric; Robertson, David J.; Zamkotsian, Frederic

    2004-07-01

    Smart Focal Planes are devices that enable the efficient sampling of a telescope's focal plane to feed spectroscopic and imaging instruments. Examples are integral field units (fiber and image slicers), cryogenic beam manipulators, and MOEMS (micro-opto-electromechanical systems) such as miniature slit shutters. These technologies are critical in making best use of the current 8m class telescopes for key science goals such as spectroscopic surveys of high redshift galaxies, and will be even more important for Extremely Large Telescope (ELT) instruments. In fact, the density of pixels in an ELT focal plane with several milliarcsecond resolution will mean that sub-sampling of the field will be needed even for imaging. We have proposed a joint European project to develop these technologies, building on expertise from partners in the UK, France, the Netherlands, Spain, Germany and others, and led by the UK. We describe the current status of these technologies, showing how they will contribute to the feasibility and performance of proposed instruments for ELTs, and concentrating on capabilities within Europe. We then outline the proposed future developments, highlighting the technical challenges, such as the difficulties of manufacturing and verifying complex image slicers with thousands of optical surfaces, and building highly reliable cryogenic mechanisms such as pick-off arms, beam steering mirrors and reconfigurble slit mechanisms.

  2. Fast & Furious focal-plane wavefront sensing

    NARCIS (Netherlands)

    Korkiakoski, V.A.; Keller, C.U.; Doelman, N.; Kenworthy, M.; Otten, G.; Verhaegen, M.H.G.

    2014-01-01

    We present two complementary algorithms suitable for using focal-plane measurements to control a wavefront corrector with an extremely high-spatial resolution. The algorithms use linear approximations to iteratively minimize the aberrations seen by the focal-plane camera. The first algorithm, Fast &

  3. Focal-plane sensor-processor chips

    CERN Document Server

    Zarándy, Ákos

    2011-01-01

    Focal-Plane Sensor-Processor Chips explores both the implementation and application of state-of-the-art vision chips. Presenting an overview of focal plane chip technology, the text discusses smart imagers and cellular wave computers, along with numerous examples of current vision chips.

  4. Solid-state curved focal plane arrays

    Science.gov (United States)

    Nikzad, Shouleh (Inventor); Hoenk, Michael (Inventor); Jones, Todd (Inventor)

    2010-01-01

    The present invention relates to curved focal plane arrays. More specifically, the present invention relates to a system and method for making solid-state curved focal plane arrays from standard and high-purity devices that may be matched to a given optical system. There are two ways to make a curved focal plane arrays starting with the fully fabricated device. One way, is to thin the device and conform it to a curvature. A second way, is to back-illuminate a thick device without making a thinned membrane. The thick device is a special class of devices; for example devices fabricated with high purity silicon. One surface of the device (the non VLSI fabricated surface, also referred to as the back surface) can be polished to form a curved surface.

  5. Optical interconnections to focal plane arrays

    Energy Technology Data Exchange (ETDEWEB)

    Rienstra, J.L.; Hinckley, M.K.

    2000-11-01

    The authors have successfully demonstrated an optical data interconnection from the output of a focal plane array to the downstream data acquisition electronics. The demonstrated approach included a continuous wave laser beam directed at a multiple quantum well reflectance modulator connected to the focal plane array analog output. The output waveform from the optical interconnect was observed on an oscilloscope to be a replica of the input signal. They fed the output of the optical data link to the same data acquisition system used to characterize focal plane array performance. Measurements of the signal to noise ratio at the input and output of the optical interconnection showed that the signal to noise ratio was reduced by a factor of 10 or more. Analysis of the noise and link gain showed that the primary contributors to the additional noise were laser intensity noise and photodetector receiver noise. Subsequent efforts should be able to reduce these noise sources considerably and should result in substantially improved signal to noise performance. They also observed significant photocurrent generation in the reflectance modulator that imposes a current load on the focal plane array output amplifier. This current loading is an issue with the demonstrated approach because it tends to negate the power saving feature of the reflectance modulator interconnection concept.

  6. MTI Focal Plane Assembly Design and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Ballard, M.; Rienstra, J.L.

    1999-06-17

    The focal plane assembly for the Multispectral Thermal Imager (MTI) consists of sensor chip assemblies, optical filters, and a vacuum enclosure. Sensor chip assemblies, composed of linear detector arrays and readout integrated circuits, provide spatial resolution in the cross-track direction for the pushbroom imager. Optical filters define 15 spectral bands in a range from 0.45 {micro}m to 10.7 {micro}m. All the detector arrays are mounted on a single focal plane and are designed to operate at 75 K. Three pairs of sensor chip assemblies (SCAs) are required to provide cross-track coverage in all 15 spectral bands. Each pair of SCAs includes detector arrays made from silicon, iridium antimonide, and mercury cadmium telluride. Read out integrated circuits multiplex the signals from the detectors to 18 separate video channels. Optical filter assemblies defining the spectral bands are mounted over the linear detector arrays. Each filter assembly consists of several filter strips bonded together side-by-side. The MTI focal plane assembly has been integrated with the rest of the payload and has undergone detailed testing and calibration. This paper includes representative test data for the various spectral bands and the overall performance of the focal plane assembly.

  7. Laser Dazzling of Focal Plane Array Cameras

    NARCIS (Netherlands)

    Schleijpen, H.M.A.; Dimmeler, A.; Eberle, B; Heuvel, J.C. van den; Mieremet, A.L.; Bekman, H.H.P.T.; Mellier, B.

    2007-01-01

    Laser countermeasures against infrared focal plane array cameras aim to saturate the full camera image. In this paper we will discuss the results of dazzling experiments performed with MWIR lasers. In the “low energy” pulse regime we observe an increasing saturated area with increasing power. The si

  8. Focal Plane Image Assembly of Subpixel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper describes the scanning assembly principle and construction of scanning assembly sample.The factors that affect assembly accuracy are analyzed.There are two steps in CCD focal plane scanning assembly.The first is rough assembly,and the second is accurate assembly.In this paper,the moiré fringe is introduced in judging assembly accuracy directly and accurately.The equation for optical transmission characteristics of CCD Moiré fringes is presented.The measurement of Moiré fringes can be completed when some conditions are satisfied.2D-assembly error can be obtained by using digital correlation filtering technique.Finally,the result of focal plane scanning assembly is presented.The result is in good accordance with theory.

  9. Staring Focal Plane Array System Modeling

    Science.gov (United States)

    1989-12-01

    mod- eling. This chapter presents background material needed to understand basic Focal Plane Array technology, the linear systems theory commonly... Linear systems theory is commonly used to assess the performance of imaging systems by describing the system’s response to different spatial frequencies...account for the nonlinearities (edge enhancement, adaptive spatial filtering) intro- duced by the eye/brain is not clear. How far can linear systems theory and

  10. Characterization of DECam focal plane detectors

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, H.Thomas; Angstadt, Robert; Campa, Julia; Cease, Herman; Derylo, Greg; Emes, John H.; Estrada, Juan; Kibik, Donna; Flaugher, Brenna L.; Holland, Steve E.; Jonas, Michelle; /Fermilab /Madrid, CIEMAT /LBL, Berkeley /Argonne /Pennsylvania U.

    2008-06-01

    DECam is a 520 Mpix, 3 square-deg FOV imager being built for the Blanco 4m Telescope at CTIO. This facility instrument will be used for the 'Dark Energy Survey' of the southern galactic cap. DECam has chosen 250 ?m thick CCDs, developed at LBNL, with good QE in the near IR for the focal plane. In this work we present the characterization of these detectors done by the DES team, and compare it to the DECam technical requirements. The results demonstrate that the detectors satisfy the needs for instrument.

  11. Characterization of DECam focal plane detectors

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, H.Thomas; Angstadt, Robert; Campa, Julia; Cease, Herman; Derylo, Greg; Emes, John H.; Estrada, Juan; Kibik, Donna; Flaugher, Brenna L.; Holland, Steve E.; Jonas, Michelle; /Fermilab /Madrid, CIEMAT /LBL, Berkeley /Argonne /Pennsylvania U.

    2008-06-01

    DECam is a 520 Mpix, 3 square-deg FOV imager being built for the Blanco 4m Telescope at CTIO. This facility instrument will be used for the 'Dark Energy Survey' of the southern galactic cap. DECam has chosen 250 ?m thick CCDs, developed at LBNL, with good QE in the near IR for the focal plane. In this work we present the characterization of these detectors done by the DES team, and compare it to the DECam technical requirements. The results demonstrate that the detectors satisfy the needs for instrument.

  12. Fast & Furious focal-plane wavefront sensing

    CERN Document Server

    Korkiakoski, Visa; Doelman, Niek; Kenworthy, Matthew; Otten, Gilles; Verhaegen, Michel

    2014-01-01

    We present two complementary algorithms suitable for using focal-plane measurements to control a wavefront corrector with an extremely high spatial resolution. The algorithms use linear approximations to iteratively minimize the aberrations seen by the focal-plane camera. The first algorithm, Fast & Furious (FF), uses a weak-aberration assumption and pupil symmetries to achieve fast wavefront reconstruction. The second algorithm, an extension to FF, can deal with an arbitrary pupil shape; it uses a Gerchberg-Saxton style error reduction to determine the pupil amplitudes. Simulations and experimental results are shown for a spatial light modulator controlling the wavefront with a resolution of 170 x 170 pixels. The algorithms increase the Strehl ratio from ~0.75 to 0.98-0.99, and the intensity of the scattered light is reduced throughout the whole recorded image of 320 x 320 pixels. The remaining wavefront rms error is estimated to be ~0.15 rad with FF and ~0.10 rad with FF-GS.

  13. Quantum-Well Infrared Photodetector (QWIP) Focal Plane Assembly

    Science.gov (United States)

    Jhabvala, Murzy; Jhabvala, Christine A.; Ewin, Audrey J.; Hess, Larry A.; Hartmann, Thomas M.; La, Anh T.

    2012-01-01

    A paper describes the Thermal Infrared Sensor (TIRS), a QWIP-based instrument intended to supplement the Operational Land Imager (OLI) for the Landsat Data Continuity Mission (LDCM). The TIRS instrument is a far-infrared imager operating in the pushbroom mode with two IR channels: 10.8 and 12 microns. The focal plane will contain three 640x512 QWIP arrays mounted on a silicon substrate. The silicon substrate is a custom-fabricated carrier board with a single layer of aluminum interconnects. The general fabrication process starts with a 4-in. (approx.10-cm) diameter silicon wafer. The wafer is oxidized, a single substrate contact is etched, and aluminum is deposited, patterned, and alloyed. This technology development is aimed at incorporating three large-format infrared detecting arrays based on GaAs QWIP technology onto a common focal plane with precision alignment of all three arrays. This focal plane must survive the rigors of flight qualification and operate at a temperature of 43 K (-230 C) for five years while orbiting the Earth. The challenges presented include ensuring thermal compatibility among all the components, designing and building a compact, somewhat modular system and ensuring alignment to very tight levels. The multi-array focal plane integrated onto a single silicon substrate is a new application of both QWIP array development and silicon wafer scale integration. The Invar-based assembly has been tested to ensure thermal reliability.

  14. Composite x-ray image assembly for large-field digital mammography with one- and two-dimensional positioning of a focal plane array

    Science.gov (United States)

    Halama, G.; McAdoo, J.; Liu, H.

    1998-01-01

    To demonstrate the feasibility of a novel large-field digital mammography technique, a 1024 x 1024 pixel Loral charge-coupled device (CCD) focal plane array (FPA) was positioned in a mammographic field with one- and two-dimensional scan sequences to obtain 950 x 1800 pixel and 3600 x 3600 pixel composite images, respectively. These experiments verify that precise positioning of FPAs produced seamless composites and that the CCD mosaic concept has potential for high-resolution, large-field imaging. The proposed CCD mosaic concept resembles a checkerboard pattern with spacing left between the CCDs for the driver and readout electronics. To obtain a complete x-ray image, the mosaic must be repositioned four times, with an x-ray exposure at each position. To reduce the patient dose, a lead shield with appropriately patterned holes is placed between the x-ray source and the patient. The high-precision motorized translation stages and the fiber-coupled-scintillating-screen-CCD sensor assembly were placed in the position usually occupied by the film cassette. Because of the high mechanical precision, seamless composites were constructed from the subimages. This paper discusses the positioning, image alignment procedure, and composite image results. The paper only addresses the formation of a seamless composite image from subimages and will not consider the effects of the lead shield, multiple CCDs, or the speed of motion.

  15. Smart trigger logic for focal plane arrays

    Science.gov (United States)

    Levy, James E; Campbell, David V; Holmes, Michael L; Lovejoy, Robert; Wojciechowski, Kenneth; Kay, Randolph R; Cavanaugh, William S; Gurrieri, Thomas M

    2014-03-25

    An electronic device includes a memory configured to receive data representing light intensity values from pixels in a focal plane array and a processor that analyzes the received data to determine which light values correspond to triggered pixels, where the triggered pixels are those pixels that meet a predefined set of criteria, and determines, for each triggered pixel, a set of neighbor pixels for which light intensity values are to be stored. The electronic device also includes a buffer that temporarily stores light intensity values for at least one previously processed row of pixels, so that when a triggered pixel is identified in a current row, light intensity values for the neighbor pixels in the previously processed row and for the triggered pixel are persistently stored, as well as a data transmitter that transmits the persistently stored light intensity values for the triggered and neighbor pixels to a data receiver.

  16. Electro-Optical Characteristics of P+n In0.53Ga0.47As Hetero-Junction Photodiodes in Large Format Dense Focal Plane Arrays

    Science.gov (United States)

    DeWames, R.; Littleton, R.; Witte, K.; Wichman, A.; Bellotti, E.; Pellegrino, J.

    2015-08-01

    This paper is concerned with focal plane array (FPA) data and use of analytical and three-dimensional numerical simulation methods to determine the physical effects and processes limiting performance. For shallow homojunction P+n designs the temperature dependence of dark current for T InGaAs interface. In this description the fitting property is the effective conductivity, σ eff( T), in mho cm-1. Variation in the data suggests σ eff (300 K) values of 1.2 × 10-11-4.6 × 10-11 mho cm-1). Substrate removal extends the quantum efficiency (QE) spectral band into the visible region. However, dead-layer effects limit the QE to 10% at a wavelength of 0.5 μm. For starlight-no moon illumination conditions, the signal-to-noise ratio is estimated to be 50 at an operating temperature of 300 K. A major result of the 3D numerical simulation of the device is the prediction of a perimeter G-R current not associated with the properties of the metallurgical interface. Another is the prediction that for a junction positioned in the larger band gap InP cap layer the QE is bias-dependent and that a relatively large reverse bias ≥0.9 V is needed for the QE to saturate to the shallow homojunction value. At this higher bias the dark current is larger than the shallow homojunction value. The 3D numerical model and the analytical model agree in predicting and explaining the measured radiatively limited diffusion current originating at the n-side of the junction. The calculations of the area-dependent G-R current for the condition studied are also in agreement. Unique advantages of the 3D numerical simulation are the ability to mimic real device structures, achieve deeper understanding of the real physical effects associated with the various methods of junction formation, and predict how device designs will function.

  17. Achromatic Focal Plane Mask for Exoplanet Imaging Coronagraphy

    Science.gov (United States)

    Newman, Kevin Edward; Belikov, Ruslan; Guyon, Olivier; Balasubramanian, Kunjithapatham; Wilson, Dan

    2013-01-01

    Recent advances in coronagraph technologies for exoplanet imaging have achieved contrasts close to 1e10 at 4 lambda/D and 1e-9 at 2 lambda/D in monochromatic light. A remaining technological challenge is to achieve high contrast in broadband light; a challenge that is largely limited by chromaticity of the focal plane mask. The size of a star image scales linearly with wavelength. Focal plane masks are typically the same size at all wavelengths, and must be sized for the longest wavelength in the observational band to avoid starlight leakage. However, this oversized mask blocks useful discovery space from the shorter wavelengths. We present here the design, development, and testing of an achromatic focal plane mask based on the concept of optical filtering by a diffractive optical element (DOE). The mask consists of an array of DOE cells, the combination of which functions as a wavelength filter with any desired amplitude and phase transmission. The effective size of the mask scales nearly linearly with wavelength, and allows significant improvement in the inner working angle of the coronagraph at shorter wavelengths. The design is applicable to almost any coronagraph configuration, and enables operation in a wider band of wavelengths than would otherwise be possible. We include initial results from a laboratory demonstration of the mask with the Phase Induced Amplitude Apodization coronagraph.

  18. A compact thermal infrared imaging radiometer with high spatial resolution and wide swath for a small satellite using a large format uncooled infrared focal plane array

    Science.gov (United States)

    Tatsumi, Kenji; Sakuma, Fumihiro; Kikuchi, Masakuni; Tanii, Jun; Kawanishi, Toneo; Ueno, Shinichi; Kuga, Hideki

    2014-10-01

    In this paper, we present a feasibility study for the potential of a high spatial resolution and wide swath thermal infrared (TIR) imaging radiometer for a small satellite using a large format uncooled infrared focal plane array (IR-FPA). The preliminary TIR imaging radiometer designs were performed. One is a panchromatic (mono-band) imaging radiometer (8-12μm) with a large format 2000 x 1000 pixels uncooled IR-FPA with a pixel pitch of 15 μm. The other is a multiband imaging radiometer (8.8μm, 10.8μm, 11.4μm). This radiometer is employed separate optics and detectors for each wave band. It is based on the use of a 640 x 480 pixels uncooled IR-FPA with a pixel pitch of 25 μm. The thermal time constant of an uncooled IR-FPA is approximately 10-16ms, and introduces a constraint to the satellite operation to achieve better signal-to-noise ratio, MTF and linearity performances. The study addressed both on-ground time-delayintegration binning and staring imaging solutions, although a staring imaging was preferred after trade-off. The staring imaging requires that the line of sight of the TIR imaging radiometer gazes at a target area during the acquisition time of the image, which can be obtained by rotating the satellite or a steering mirror around the pitch axis. The single band radiometer has been designed to yield a 30m ground sample distance over a 30km swath width from a satellite altitude of 500km. The radiometric performance, enhanced with staring imaging, is expected to yield a NETD less than 0.5K for a 300K ground scene. The multi-band radiometer has three spectral bands with spatial resolution of 50m and swath width of 24km. The radiometric performance is expected to yield a NETD less than 0.85K. We also showed some preliminary simulation results on volcano, desert/urban scenes, and wildfire.

  19. Hyperspectral Longwave Infrared Focal Plane Array and Camera Based on Quantum Well Infrared Photodetectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a hyperspectral focal plane array and camera imaging in a large number of sharp hyperspectral bands in the thermal infrared. The camera is...

  20. Nonuniformity compensation for IR focal plane array sensors

    Science.gov (United States)

    Venkateswarlu, Ronda; Er, Meng H.; Gan, Yu H.; Fong, Yew C.

    1997-08-01

    Recent reports indicate that cooled and uncooled IR focal plane array sensors are progressing to a field-worthy level for commercial and defense applications. They offer higher sensitivity, amenability to signal processing and mechanical simplicity. However these sensors contain large detector-to- detector dark current (offset) and responsivity (gain) variations. These variations result in a severe problem called fixed pattern noise that can mask/distort the image obtained from the sensor. The correction process is generally termed as nonuniformity compensation. Conventional two-point compensation techniques are accurate enough, but require built-in controllable temperature references along with mechanical and electro-optical shutters. Therefore this compensation technique detracts the mechanical simplicity of using IR focal plane arrays. Scene-based nonuniformity techniques dispenses with the requirement of temperature references and shutters, but are not accurate enough for certain applications. This paper discusses two-point and scene-based nonuniformity compensation algorithms and proposes an empirical formula to automatically calculate the scene constants, which is an essential step towards practical applications. This paper reports the analyzed results of testing the algorithms on a number of IR images. A practical problem of 'artifacts' which arise when using scene-based nonuniformity compensation is also discussed. A common hardware scheme to implement both the algorithms is also presented in this paper.

  1. Application of cooled IR focal plane arrays in thermographic cameras

    Science.gov (United States)

    Vollheim, B.; Gaertner, M.; Dammass, G.; Krausz, M.

    2016-05-01

    The usage of cooled IR Focal Plane Array detectors in thermographic or radiometric thermal imaging cameras, respectively, leads to special demands on these detectors, which are discussed in this paper. For a radiometric calibration of wide temperature measuring ranges from -40 up to 2,000 °C, a linear and time-stable response of the photodiode array has to be ensured for low as well as high radiation intensities. The maximum detectable photon flux is limited by the allowed shift of the photodiode's bias that should remain in the linear part of the photodiode's I(V) curve even for the highest photocurrent. This limits the measurable highest object temperature in practice earlier than the minimum possible integration time. Higher temperature measuring ranges are realized by means of neutral or spectral filters. Defense and Security applications normally provide images at the given ambient temperature with small hot spots. The usage of radiometric thermal imagers for thermography often feature larger objects with a high temperature contrast to the background. This should not generate artifacts in the image, like pixel patterns or stripes. Further issues concern the clock regime or the sub-frame capabilities of the Read-Out-Circuit and the frame rate dependency of the signal. We will briefly describe the demands on the lens design for thermal imaging cameras when using cooled IR Focal Plane Array detectors with large apertures.

  2. LiteBIRD: Mission Overview and Focal Plane Layout

    Science.gov (United States)

    Matsumura, T.; Akiba, Y.; Arnold, K.; Borrill, J.; Chendra, R.; Chinone, Y.; Cukierman, A.; de Haan, T.; Dobbs, M.; Dominjon, A.; Elleflot, T.; Errard, J.; Fujino, T.; Fuke, H.; Goeckner-wald, N.; Halverson, N.; Harvey, P.; Hasegawa, M.; Hattori, K.; Hattori, M.; Hazumi, M.; Hill, C.; Hilton, G.; Holzapfel, W.; Hori, Y.; Hubmayr, J.; Ichiki, K.; Inatani, J.; Inoue, M.; Inoue, Y.; Irie, F.; Irwin, K.; Ishino, H.; Ishitsuka, H.; Jeong, O.; Karatsu, K.; Kashima, S.; Katayama, N.; Kawano, I.; Keating, B.; Kibayashi, A.; Kibe, Y.; Kida, Y.; Kimura, K.; Kimura, N.; Kohri, K.; Komatsu, E.; Kuo, C. L.; Kuromiya, S.; Kusaka, A.; Lee, A.; Linder, E.; Matsuhara, H.; Matsuoka, S.; Matsuura, S.; Mima, S.; Mitsuda, K.; Mizukami, K.; Morii, H.; Morishima, T.; Nagai, M.; Nagasaki, T.; Nagata, R.; Nakajima, M.; Nakamura, S.; Namikawa, T.; Naruse, M.; Natsume, K.; Nishibori, T.; Nishijo, K.; Nishino, H.; Nitta, T.; Noda, A.; Noguchi, T.; Ogawa, H.; Oguri, S.; Ohta, I. S.; Otani, C.; Okada, N.; Okamoto, A.; Okamoto, A.; Okamura, T.; Rebeiz, G.; Richards, P.; Sakai, S.; Sato, N.; Sato, Y.; Segawa, Y.; Sekiguchi, S.; Sekimoto, Y.; Sekine, M.; Seljak, U.; Sherwin, B.; Shinozaki, K.; Shu, S.; Stompor, R.; Sugai, H.; Sugita, H.; Suzuki, T.; Suzuki, A.; Tajima, O.; Takada, S.; Takakura, S.; Takano, K.; Takei, Y.; Tomaru, T.; Tomita, N.; Turin, P.; Utsunomiya, S.; Uzawa, Y.; Wada, T.; Watanabe, H.; Westbrook, B.; Whitehorn, N.; Yamada, Y.; Yamasaki, N.; Yamashita, T.; Yoshida, M.; Yoshida, T.; Yotsumoto, Y.

    2016-08-01

    LiteBIRD is a proposed CMB polarization satellite project to probe the inflationary B-mode signal. The satellite is designed to measure the tensor-to-scalar ratio with a 68 % confidence level uncertainty of σ _r<10^{-3}, including statistical, instrumental systematic, and foreground uncertainties. LiteBIRD will observe the full sky from the second Lagrange point for 3 years. We have a focal plane layout for observing frequency coverage that spans 40-402 GHz to characterize the galactic foregrounds. We have two detector candidates, transition-edge sensor bolometers and microwave kinetic inductance detectors. In both cases, a telecentric focal plane consists of approximately 2× 10^3 superconducting detectors. We will present the mission overview of LiteBIRD, the project status, and the TES focal plane layout.

  3. Development status of the AIRS IR focal plane assembly

    Science.gov (United States)

    Libonate, G. Scott; Denley, Brian; Krueger, Eric E.; Rutter, James H., Jr.; Stobie, James A.; Terzis, C. L.

    1997-10-01

    The atmospheric infrared sounder (AIRS) is a high resolution IR spectrometer (lambda/(Delta) (lambda) congruent 1200) which will map global temperatures and identify atmospheric aerosols from orbit by monitoring key atmospheric absorption lines. The focal plane consists of ten bilinear photovoltaic (PV) and two photoconductive (PC) HgCdTe detector arrays (modules) sampling a 3.7 to 15.4 micrometer spectral window in 15 bands. To attain the desired temperature accuracy, tight constraints on focal plane performance parameters such as linearity better than 0.1%, quantum efficiency (QE) on the order of 70%, low noise or noise equivalent quantum flux density (NEQFD), and no outages at key spectral lines have been imposed. Assessment of focal plane performance begins at the detector and readout levels where flight candidate detector arrays and CMOS readouts are selected. PV detector arrays and their readouts are hybridized (PC modules are wire-bonded directly) into modules which are then individually tested under simulated flight conditions. Five of the twelve module types are incorporated into an engineering-level (EM) focal plane upon which the module level tests are repeated as a prelude to the fabrication and testing of a separate, fully populated, flight-level (PFM) focal plane. Module testing has demonstrated that many difficult system requirements have been met, and work continues to optimize module performance. Lockheed Martin IR Imaging Systems' (LMIRIS) overall design of the infrared (IR) detector/Dewar assembly and focal plane development program is given, followed by a summary of PV and PC module data.

  4. Wavelet Transform of Fixed Pattern Noise in Focal Plane Arrays

    Science.gov (United States)

    1994-02-01

    AD-A276 963 1111111111 I NAWCWPNS TP 8185 Wavelet Transform of Fixed Pattern Noise in Focal Plane Arrays OTIC by ELECTE Dr. Gary Hewer MAR 151994 and...REPORT TYPE AND DATES COVERED IFebruary 1994 Final; 199 ,L TTLE ND SBTILE LFUNDNG UBER Wavelet Transform of Fixed Pattern Noise in Focal Plane Arrays...nonlinearity 71,(w) = sgn(w)(IwI-t). with threshold t to each empirical sample value w in the wavelet transform d scales. After thresholding the wavelet

  5. The bolometric focal plane array of the Polarbear CMB experiment

    CERN Document Server

    Arnold, K; Anthony, A E; Barron, D; Boettger, D; Borrill, J; Chapman, S; Chinone, Y; Dobbs, M A; Errard, J; Fabbian, G; Flanigan, D; Fuller, G; Ghribi, A; Grainger, W; Halverson, N; Hasegawa, M; Hattori, K; Hazumi, M; Holzapfel, W L; Howard, J; Hyland, P; Jaffe, A; Keating, B; Kermish, Z; Kisner, T; Jeune, M Le; Lee, A T; Linder, E; Lungu, M; Matsuda, F; Matsumura, T; Miller, N J; Meng, X; Morii, H; Moyerman, S; Myers, M J; Nishino, H; Paar, H; Quealy, E; Reichardt, C; Richards, P L; Ross, C; Shimizu, A; Shimmin, C; Shimon, M; Sholl, M; Siritanasak, P; Spieler, H; Stebor, N; Steinbach, B; Stompor, R; Suzuki, A; Tomaru, T; Tucker, C; Zahn, O

    2012-01-01

    The Polarbear Cosmic Microwave Background (CMB) polarization experiment is currently observing from the Atacama Desert in Northern Chile. It will characterize the expected B-mode polarization due to gravitational lensing of the CMB, and search for the possible B-mode signature of inflationary gravitational waves. Its 250 mK focal plane detector array consists of 1,274 polarization-sensitive antenna-coupled bolometers, each with an associated lithographed band-defining filter. Each detector's planar antenna structure is coupled to the telescope's optical system through a contacting dielectric lenslet, an architecture unique in current CMB experiments. We present the initial characterization of this focal plane.

  6. Performance of an Achromatic Focal Plane Mask for Exoplanet Imaging Coronagraphy

    Science.gov (United States)

    Newman, Kevin; Belikov, Ruslan; Pluzhnik, Eugene; Balasubramanian, Kunjithapatham; Wilson, Dan

    2014-01-01

    Coronagraph technology combined with wavefront control is close to achieving the contrast and inner working angle requirements in the lab necessary to observe the faint signal of an Earth-like exoplanet in monochromatic light. An important remaining technological challenge is to achieve high contrast in broadband light. Coronagraph bandwidth is largely limited by chromaticity of the focal plane mask, which is responsible for blocking the stellar PSF. The size of a stellar PSF scales linearly with wavelength; ideally, the size of the focal plane mask would also scale with wavelength. A conventional hard-edge focal plane mask has a fixed size, normally sized for the longest wavelength in the observational band to avoid starlight leakage. The conventional mask is oversized for shorter wavelengths and blocks useful discovery space. Recently we presented a solution to the size chromaticity challenge with a focal plane mask designed to scale its effective size with wavelength. In this paper, we analyze performance of the achromatic size-scaling focal plane mask within a Phase Induced Amplitude Apodization (PIAA) coronagraph. We present results from wavefront control around the achromatic focal plane mask, and demonstrate the size-scaling effect of the mask with wavelength. The edge of the dark zone, and therefore the inner working angle of the coronagraph, scale with wavelength. The achromatic mask enables operation in a wider band of wavelengths compared with a conventional hard-edge occulter.

  7. Cryogenic mechatronic design of the HIFI Focal Plane Chopper

    NARCIS (Netherlands)

    Huisman, R.; Aalders, J. W. G.; Eggens, M. J.; Evers, J.; Jacobs, H. M.; van Leeuwen, B. J.; Nieuwenhuizen, A. C. T.; Ploeger, G. R.; Wildeman, K. J.; Jayawardhana, B.; Scherpen, J. M. A.

    2011-01-01

    This paper discusses the cryogenic mechatronic development of the Focal Plane Chopper (FPC) mechanism in the Heterodyne Instrument for the Far Infrared (HIFI) which is one of the science instruments on board the Herschel space telescope. The extreme cryogenic environment, in which the mechanism has

  8. Dense Focal Plane Arrays for Pushbroom Satellite Radiometers

    DEFF Research Database (Denmark)

    Iupikov, O. A.; Ivashina, M. V.; Pontoppidan, K.

    2014-01-01

    Performance of a dense focal plane array feeding an offset toroidal reflector antenna system is studied and discussed in the context of a potential application in multi-beam radiometers for ocean surveillance. We present a preliminary design of the array feed for the 5-m diameter antenna at X...

  9. Focal Plane Alignment Utilizing Optical CMM

    Science.gov (United States)

    Liebe, Carl Christian; Meras, Patrick L.; Clark, Gerald J.; Sedaka, Jack J.; Kaluzny, Joel V.; Hirsch, Brian; Decker, Todd A.; Scholtz, Christopher R.

    2012-01-01

    In many applications, an optical detector has to be located relative to mechanical reference points. One solution is to specify stringent requirements on (1) mounting the optical detector relative to the chip carrier, (2) soldering the chip carrier onto the printed circuit board (PCB), and (3) installing the PCB to the mechanical structure of the subsystem. Figure 1 shows a sketch of an optical detector mounted relative to mechanical reference with high positional accuracy. The optical detector is typically a fragile wafer that cannot be physically touched by any measurement tool. An optical coordinate measuring machine (CMM) can be used to position optical detectors relative to mechanical reference points. This approach will eliminate all requirements on positional tolerances. The only requirement is that the PCB is manufactured with oversized holes. An exaggerated sketch of this situation is shown in Figure 2. The sketch shows very loose tolerances on mounting the optical detector in the chip carrier, loose tolerance on soldering the chip carrier to the PCB, and finally large tolerance on where the mounting screws are located. The PCB is held with large screws and oversized holes. The PCB is mounted loosely so it can move freely around. The optical CMM measures the mechanical reference points. Based on these measurements, the required positions of the optical detector corners can be calculated. The optical CMM is commanded to go to the position where one detector corner is supposed to be. This is indicated with the cross-hairs in Figure 2(a). This figure is representative of the image of the optical CMM monitor. Using a suitable tapping tool, the PCB is manually tapped around until the corner of the optical detector is at the crosshairs of the optical CMM. The CMM is commanded to another corner, and the process is repeated a number of times until all corners of the optical detector are within a distance of 10 to 30 microns of the required position. The situation

  10. Next generation sub-millimeter wave focal plane array coupling concepts: an ESA TRP project to develop multichroic focal plane pixels for future CMB polarization experiments

    Science.gov (United States)

    Trappe, N.; Bucher, M.; De Bernardis, P.; Delabrouille, J.; Deo, P.; DePetris, M.; Doherty, S.; Ghribi, A.; Gradziel, M.; Kuzmin, L.; Maffei, B.; Mahashabde, S.; Masi, S.; Murphy, J. A.; Noviello, F.; O'Sullivan, C.; Pagano, L.; Piacentini, F.; Piat, M.; Pisano, G.; Robinson, M.; Stompor, R.; Tartari, A.; van der Vorst, M.; Verhoeve, P.

    2016-07-01

    The main objective of this activity is to develop new focal plane coupling array concepts and technologies that optimise the coupling from reflector optics to the large number of detectors for next generation sub millimetre wave telescopes particularly targeting measurement of the polarization of the cosmic microwave background (CMB). In this 18 month TRP programme the consortium are tasked with developing, manufacturing and experimentally verifying a prototype multichroic pixel which would be suitable for the large focal plane arrays which will be demanded to reach the required sensitivity of future CMB polarization missions. One major development was to have multichroic operation to potentially reduce the required focal plane size of a CMB mission. After research in the optimum telescope design and definition of requirements based on a stringent science case review, a number of compact focal plane architecture concepts were investigated before a pixel demonstrator consisting of a planar mesh lens feeding a backend Resonant Cold Electron Bolometer RCEB for filtering and detection of the dual frequency signal was planned for manufacture and test. In this demonstrator the frequencies of the channels was chosen to be 75 and 105 GHz in the w band close to the peak CMB signal. In the next year the prototype breadboards will be developed to test the beams produced by the manufactured flat lenses fed by a variety of antenna configurations and the spectral response of the RCEBs will also be verified.

  11. METHOD FOR DETERMINATION OF FOCAL PLANE LOCATION OF FOCUSING COMPONENTS

    Directory of Open Access Journals (Sweden)

    A. I. Ivashko

    2017-01-01

    Full Text Available Mass-production of different laser systems often requires utilization of the focal spot size method for determination of output laser beam spatial characteristics. The main challenge of this method is high accuracy maintenance of a CCD camera beam profiler in the collecting lens focal plane. The aim of our work is development of new method for placing of photodetector array in the collecting lens focal plane with high accuracy.Proposed technique is based on focusing of several parallel laser beams. Determination of the focal plane position requires only longitudinal translation of the CCD-camera to find a point of laser beams intersection. Continuous-wave (CW diode-pumped laser emitting in the spectral region near 1μm was created to satisfy the requirements of the developed technique. Designed microchip laser generates two stigmatic Gaussian beams with automatically parallel beam axes due to independent pumping of different areas of the one microchip crystal having the same cavity mirrors.It was theoretically demonstrated that developed method provides possibility of the lenses focal plane determination with 1 % accuracy. The microchip laser generates two parallel Gaussian beams with divergence of about 10 mrad. Laser output power can be varied in the range of 0.1–1.5 W by changing the pumping laser diode electrical current. The distance between two beam axes can be changed in the range of 0.5–5.0 mm.We have proposed method for determination of positive lens focal plane location by using of CCDcamera and two laser beams with parallel axes without utilization of additional optical devices. We have developed CW longitudinally diode pumped microchip laser emitting in the 1-μm spectral region that can be used in the measuring instrument that doesn’t require precision mechanical components for determination of focal plane location with 1 % accuracy. The overall dimensions of laser head was 70 × 40 × 40 mm3 and maximum power consumption was

  12. Precise annealing of focal plane arrays for optical detection

    Energy Technology Data Exchange (ETDEWEB)

    Bender, Daniel A.

    2015-09-22

    Precise annealing of identified defective regions of a Focal Plane Array ("FPA") (e.g., exclusive of non-defective regions of the FPA) facilitates removal of defects from an FPA that has been hybridized and/or packaged with readout electronics. Radiation is optionally applied under operating conditions, such as under cryogenic temperatures, such that performance of an FPA can be evaluated before, during, and after annealing without requiring thermal cycling.

  13. BICEP3 focal plane design and detector performance

    CERN Document Server

    Hui, H; Ahmed, Z; Alexander, K D; Amiri, M; Barkats, D; Benton, S J; Bischoff, C A; Bock, J J; Boenish, H; Bowens-Rubin, R; Buder, I; Bullock, E; Buza, V; Connors, J; Filippini, J P; Fliescher, S; Grayson, J A; Halpern, M; Harrison, S; Hilton, G C; Hristov, V V; Irwin, K D; Kang, J; Karkare, K S; Karpel, E; Kefeli, S; Kernasovskiy, S A; Kovac, J M; Kuo, C L; Leitch, E M; Lueker, M; Megerian, K G; Monticue, V; Namikawa, T; Netterfield, C B; Nguyen, H T; O'Brient, R; Ogburn, R W; Pryke, C; Reintsema, C D; Richter, S; Schwarz, R; Sorensen, C; Sheehy, C D; Staniszewski, Z K; Steinbach, B; Teply, G P; Thompson, K L; Tolan, J E; Tucker, C; Turner, A D; Vieregg, A G; Wandui, A; Weber, A C; Wiebe, D V; Willmert, J; Wu, W L K; Yoon, K W

    2016-01-01

    BICEP3, the latest telescope in the BICEP/Keck program, started science observations in March 2016. It is a 550mm aperture refractive telescope observing the polarization of the cosmic microwave background at 95 GHz. We show the focal plane design and detector performance, including spectral response, optical efficiency and preliminary sensitivity of the upgraded BICEP3. We demonstrate 9.72$\\mu$K$\\sqrt{\\textrm{s}}$ noise performance of the BICEP3 receiver.

  14. Performance overview of the Euclid infrared focal plane detector subsystems

    Science.gov (United States)

    Waczynski, A.; Barbier, R.; Cagiano, S.; Chen, J.; Cheung, S.; Cho, H.; Cillis, A.; Clémens, J.-C.; Dawson, O.; Delo, G.; Farris, M.; Feizi, A.; Foltz, R.; Hickey, M.; Holmes, W.; Hwang, T.; Israelsson, U.; Jhabvala, M.; Kahle, D.; Kan, Em.; Kan, Er.; Loose, M.; Lotkin, G.; Miko, L.; Nguyen, L.; Piquette, E.; Powers, T.; Pravdo, S.; Runkle, A.; Seiffert, M.; Strada, P.; Tucker, C.; Turck, K.; Wang, F.; Weber, C.; Williams, J.

    2016-07-01

    In support of the European space agency (ESA) Euclid mission, NASA is responsible for the evaluation of the H2RG mercury cadmium telluride (MCT) detectors and electronics assemblies fabricated by Teledyne imaging systems. The detector evaluation is performed in the detector characterization laboratory (DCL) at the NASA Goddard space flight center (GSFC) in close collaboration with engineers and scientists from the jet propulsion laboratory (JPL) and the Euclid project. The Euclid near infrared spectrometer and imaging photometer (NISP) will perform large area optical and spectroscopic sky surveys in the 0.9-2.02 μm infrared (IR) region. The NISP instrument will contain sixteen detector arrays each coupled to a Teledyne SIDECAR application specific integrated circuit (ASIC). The focal plane will operate at 100K and the SIDECAR ASIC will be in close proximity operating at a slightly higher temperature of 137K. This paper will describe the test configuration, performance tests and results of the latest engineering run, also known as pilot run 3 (PR3), consisting of four H2RG detectors operating simultaneously. Performance data will be presented on; noise, spectral quantum efficiency, dark current, persistence, pixel yield, pixel to pixel uniformity, linearity, inter pixel crosstalk, full well and dynamic range, power dissipation, thermal response and unit cell input sensitivity.

  15. SIRTF Focal Plane Survey: A Pre-flight Error Analysis

    Science.gov (United States)

    Bayard, David S.; Brugarolas, Paul B.; Boussalis, Dhemetrios; Kang, Bryan H.

    2003-01-01

    This report contains a pre-flight error analysis of the calibration accuracies expected from implementing the currently planned SIRTF focal plane survey strategy. The main purpose of this study is to verify that the planned strategy will meet focal plane survey calibration requirements (as put forth in the SIRTF IOC-SV Mission Plan [4]), and to quantify the actual accuracies expected. The error analysis was performed by running the Instrument Pointing Frame (IPF) Kalman filter on a complete set of simulated IOC-SV survey data, and studying the resulting propagated covariances. The main conclusion of this study is that the all focal plane calibration requirements can be met with the currently planned survey strategy. The associated margins range from 3 to 95 percent, and tend to be smallest for frames having a 0.14" requirement, and largest for frames having a more generous 0.28" (or larger) requirement. The smallest margin of 3 percent is associated with the IRAC 3.6 and 5.8 micron array centers (frames 068 and 069), and the largest margin of 95 percent is associated with the MIPS 160 micron array center (frame 087). For pointing purposes, the most critical calibrations are for the IRS Peakup sweet spots and short wavelength slit centers (frames 019, 023, 052, 028, 034). Results show that these frames are meeting their 0.14" requirements with an expected accuracy of approximately 0.1", which corresponds to a 28 percent margin.

  16. Kalman Filter for Calibrating a Telescope Focal Plane

    Science.gov (United States)

    Kang, Bryan; Bayard, David

    2006-01-01

    The instrument-pointing frame (IPF) Kalman filter, and an algorithm that implements this filter, have been devised for calibrating the focal plane of a telescope. As used here, calibration signifies, more specifically, a combination of measurements and calculations directed toward ensuring accuracy in aiming the telescope and determining the locations of objects imaged in various arrays of photodetectors in instruments located on the focal plane. The IPF Kalman filter was originally intended for application to a spaceborne infrared astronomical telescope, but can also be applied to other spaceborne and ground-based telescopes. In the traditional approach to calibration of a telescope, (1) one team of experts concentrates on estimating parameters (e.g., pointing alignments and gyroscope drifts) that are classified as being of primarily an engineering nature, (2) another team of experts concentrates on estimating calibration parameters (e.g., plate scales and optical distortions) that are classified as being primarily of a scientific nature, and (3) the two teams repeatedly exchange data in an iterative process in which each team refines its estimates with the help of the data provided by the other team. This iterative process is inefficient and uneconomical because it is time-consuming and entails the maintenance of two survey teams and the development of computer programs specific to the requirements of each team. Moreover, theoretical analysis reveals that the engineering/ science iterative approach is not optimal in that it does not yield the best estimates of focal-plane parameters and, depending on the application, may not even enable convergence toward a set of estimates.

  17. Focal-plane detector system for the KATRIN experiment

    CERN Document Server

    Amsbaugh, J F; Beglarian, A; Bergmann, T; Bichsel, H; Bodine, L I; Bonn, J; Boyd, N M; Burritt, T H; Chaoui, Z; Chilingaryan, S; Corona, T J; Doe, P J; Dunmore, J A; Enomoto, S; Fischer, J; Formaggio, J A; Fränkle, F M; Furse, D; Gemmeke, H; Glück, F; Harms, F; Harper, G C; Hartmann, J; Howe, M A; Kaboth, A; Kelsey, J; Knauer, M; Kopmann, A; Leber, M L; Martin, E L; Middleman, K J; Myers, A W; Oblath, N S; Parno, D S; Peterson, D A; Petzold, L; Phillips, D G; Renschler, P; Robertson, R G H; Schwarz, J; Steidl, M; Tcherniakhovski, D; Thümmler, T; Van Wechel, T D; VanDevender, B A; Vöcking, S; Wall, B L; Wierman, K L; Wilkerson, J F; Wüstling, S

    2014-01-01

    The focal-plane detector system for the KArlsruhe TRItium Neutrino (KATRIN) experiment consists of a multi-pixel silicon p-i-n-diode array, custom readout electronics, two superconducting solenoid magnets, an extreme high-vacuum system, a high-vacuum system, calibration and monitoring devices, a scintillating veto, and a custom data-acquisition system. It is designed to detect the low-energy electrons selected by the KATRIN main spectrometer. We describe the system and summarize its performance, both before and after its final installation.

  18. New focal plane detector system for the broad range spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Sjoreen, T.P.

    1984-01-01

    A focal plane detector system consisting of a vertical drift chamber, parallel plate avalanche counters, and an ionization chamber with segmented anodes has been installed in the Broad Range Spectrometer at the Holifield Facility at Oak Ridge. The system, which has been designed for use with light-heavy ions with energies ranging from 10 to 25 MeV/amu, has a position resolution of approx. 0.1 mm, a scattering angle resolution of approx. 3 mrad, and a mass resolution of approx. 1/60.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Focal-plane detector system for the KATRIN experiment

    Energy Technology Data Exchange (ETDEWEB)

    Amsbaugh, J.F. [Center for Experimental Nuclear Physics and Astrophysics, Department of Physics, University of Washington, Seattle, WA 98195 (United States); Barrett, J. [Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Beglarian, A.; Bergmann, T. [Institute for Data Processing and Electronics, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen (Germany); Bichsel, H.; Bodine, L.I. [Center for Experimental Nuclear Physics and Astrophysics, Department of Physics, University of Washington, Seattle, WA 98195 (United States); Bonn, J. [Institute of Physics, Johannes Gutenberg-Universität Mainz, 55099 Mainz (Germany); Boyd, N.M.; Burritt, T.H. [Center for Experimental Nuclear Physics and Astrophysics, Department of Physics, University of Washington, Seattle, WA 98195 (United States); Chaoui, Z. [Laboratory of Optoelectronics and Devices, University of Setif, UFA Setif, Setif 19000 (Algeria); Chilingaryan, S. [Institute for Data Processing and Electronics, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen (Germany); Corona, T.J. [Department of Physics, University of North Carolina, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Doe, P.J.; Dunmore, J.A.; Enomoto, S. [Center for Experimental Nuclear Physics and Astrophysics, Department of Physics, University of Washington, Seattle, WA 98195 (United States); Formaggio, J.A. [Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Fränkle, F.M. [Department of Physics, University of North Carolina, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Furse, D. [Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); and others

    2015-04-01

    The focal-plane detector system for the KArlsruhe TRItium Neutrino (KATRIN) experiment consists of a multi-pixel silicon p-i-n-diode array, custom readout electronics, two superconducting solenoid magnets, an ultra high-vacuum system, a high-vacuum system, calibration and monitoring devices, a scintillating veto, and a custom data-acquisition system. It is designed to detect the low-energy electrons selected by the KATRIN main spectrometer. We describe the system and summarize its performance after its final installation.

  1. Antenna coupled detectors for 2D staring focal plane arrays

    Science.gov (United States)

    Gritz, Michael A.; Kolasa, Borys; Lail, Brian; Burkholder, Robert; Chen, Leonard

    2013-06-01

    Millimeter-wave (mmW)/sub-mmW/THz region of the electro-magnetic spectrum enables imaging thru clothing and other obscurants such as fog, clouds, smoke, sand, and dust. Therefore considerable interest exists in developing low cost millimeter-wave imaging (MMWI) systems. Previous MMWI systems have evolved from crude mechanically scanned, single element receiver systems into very complex multiple receiver camera systems. Initial systems required many expensive mmW integrated-circuit low-noise amplifiers. In order to reduce the cost and complexity of the existing systems, attempts have been made to develop new mmW imaging sensors employing direct detection arrays. In this paper, we report on Raytheon's recent development of a unique focal plane array technology, which operates broadly from the mmW through the sub-mmW/THz region. Raytheon's innovative nano-antenna based detector enables low cost production of 2D staring mmW focal plane arrays (mmW FPA), which not only have equivalent sensitivity and performance to existing MMWI systems, but require no mechanical scanning.

  2. Planck 2015 results. XII. Full Focal Plane simulations

    CERN Document Server

    Ade, P A R; Arnaud, M; Ashdown, M; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Bartlett, J G; Bartolo, N; Battaner, E; Benabed, K; Beno\\^\\it, A; Benoit-Lévy, A; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bock, J J; Bonaldi, A; Bonavera, L; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Bucher, M; Burigana, C; Butler, R C; Calabrese, E; Cardoso, J -F; Castex, G; Catalano, A; Challinor, A; Chamballu, A; Chiang, H C; Christensen, P R; Clements, D L; Colombi, S; Colombo, L P L; Combet, C; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Désert, F -X; Dickinson, C; Diego, J M; Dolag, K; Dole, H; Donzelli, S; Doré, O; Douspis, M; Ducout, A; Dupac, X; Efstathiou, G; Elsner, F; Enßlin, T A; Eriksen, H K; Fergusson, J; Finelli, F; Forni, O; Frailis, M; Fraisse, A A; Franceschi, E; Frejsel, A; Galeotta, S; Galli, S; Ganga, K; Ghosh, T; Giard, M; Giraud-Héraud, Y; Gjerløw, E; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Gudmundsson, J E; Hansen, F K; Hanson, D; Harrison, D L; Henrot-Versillé, S; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hornstrup, A; Hovest, W; Huffenberger, K M; Hurier, G; Jaffe, A H; Jaffe, T R; Jones, W C; Juvela, M; Karakci, A; Keihänen, E; Keskitalo, R; Kiiveri, K; Kisner, T S; Kneissl, R; Knoche, J; Kunz, M; Kurki-Suonio, H; Lagache, G; Lamarre, J -M; Lasenby, A; Lattanzi, M; Lawrence, C R; Leonardi, R; Lesgourgues, J; Levrier, F; Liguori, M; Lilje, P B; Linden-Vørnle, M; Lindholm, V; López-Caniego, M; Lubin, P M; Mac\\'\\ias-Pérez, J F; Maggio, G; Maino, D; Mandolesi, N; Mangilli, A; Maris, M; Martin, P G; Mart\\'\\inez-González, E; Masi, S; Matarrese, S; McGehee, P; Meinhold, P R; Melchiorri, A; Melin, J -B; Mendes, L; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Moss, A; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Netterfield, C B; Nørgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; Oxborrow, C A; Paci, F; Pagano, L; Pajot, F; Paoletti, D; Pasian, F; Patanchon, G; Pearson, T J; Perdereau, O; Perotto, L; Perrotta, F; Pettorino, V; Piacentini, F; Piat, M; Pierpaoli, E; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polenta, G; Pratt, G W; Prézeau, G; Prunet, S; Puget, J -L; Rachen, J P; Rebolo, R; Reinecke, M; Remazeilles, M; Renault, C; Renzi, A; Ristorcelli, I; Rocha, G; Roman, M; Rosset, C; Rossetti, M; Roudier, G; Rubiño-Martín, J A; Rusholme, B; Sandri, M; Santos, D; Savelainen, M; Scott, D; Seiffert, M D; Shellard, E P S; Spencer, L D; Stolyarov, V; Stompor, R; Sudiwala, R; Sutton, D; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Terenzi, L; Toffolatti, L; Tomasi, M; Tristram, M; Tucci, M; Tuovinen, J; Valenziano, L; Valiviita, J; Van Tent, B; Vielva, P; Villa, F; Wade, L A; Wandelt, B D; Wehus, I K; Welikala, N; Yvon, D; Zacchei, A; Zonca, A

    2015-01-01

    We present the 8th Full Focal Plane simulation set (FFP8), deployed in support of the Planck 2015 results. FFP8 consists of 10 fiducial mission realizations reduced to 18144 maps, together with the most massive suite of Monte Carlo realizations of instrument noise and CMB ever generated, comprising $10^4$ mission realizations reduced to about $10^6$ maps. The resulting maps incorporate the dominant instrumental, scanning, and data analysis effects; remaining subdominant effects will be included in future updates. Generated at a cost of some 25 million CPU-hours spread across multiple high-performance-computing (HPC) platforms, FFP8 is used for the validation and verification of analysis algorithms, as well as their implementations, and for removing biases from and quantifying uncertainties in the results of analyses of the real data.

  3. Combined Approach for Nonuniformity Correction in Infrared Focal Plane Array

    Institute of Scientific and Technical Information of China (English)

    XUE Hui

    2009-01-01

    A new algorithm of nonuniformity correction for infrared focal plane array(IRFPA) is reported,which is a combined algorithm based on both the two-point correction and artificial neural networks correction.The combined algorithm is calibrated by two-point correction,and the calibrated correction coefficients are automatically modified by BP algorithm.So it is not only calibrated,but also real-time processed.In adaptive nonuniformity correction algorithm,the phenomena ghost artifact and target fade-out are avoided by edge extraction.In order to get intensified image,the modified median filters are adopted.The simulated data indicates the proposed scheme is an effective algorithm.

  4. Fixed Pattern Noise Compensation Techniques For Staring Infrared Focal Planes

    Science.gov (United States)

    Carrison, C. L.; Foss, N. A.

    1980-10-01

    To utilize the full performance advantages of staring infrared imaging systems currently under development, it is necessary to compensate for the characteristic fixed pattern "noise" which is present at the output from these infrared focal planes. Since many of the applications for staring sensor systems require low power dissipation configurations, it is necessary to develop automatic nonuniformity compensation electronics which have much lower power dissipation requirements than conventional digital compensation techniques. This paper discusses the sources of the nonuniformities and describes the typical characteristics of elevated temperature staring arrays. An analysis is given which shows how detector/charge-coupled device electrical coupling techniques strongly influence the compensation implementation, and finally a review of circuit configurations for the compensation function will be given which shows that very low power dissipation circuitry can be developed which meets the performance power dissipation requirements.

  5. Characteristics of stereo images from detectors in focal plane array.

    Science.gov (United States)

    Son, Jung-Young; Yeom, Seokwon; Chun, Joo-Hwan; Guschin, Vladmir P; Lee, Dong-Su

    2011-07-01

    The equivalent ray geometry of two horizontally aligned detectors at the focal plane of the main antenna in a millimeter wave imaging system is analyzed to reveal the reason why the images from the detectors are fused as an image with a depth sense. Scanning the main antenna in both horizontal and vertical directions makes each detector perform as a camera, and the two detectors can work like a stereo camera in the millimeter wave range. However, the stereo camera geometry is different from that of the stereo camera used in the visual spectral range because the detectors' viewing directions are diverging to each other and they are a certain distance apart. The depth sense is mainly induced by the distance between detectors. The images obtained from the detectors in the millimeter imaging system are perceived with a good depth sense. The disparities responsible for the depth sense are identified in the images.

  6. Optical-based spectral modeling of infrared focal plane arrays

    Science.gov (United States)

    Mouzali, Salima; Lefebvre, Sidonie; Rommeluère, Sylvain; Ferrec, Yann; Primot, Jérôme

    2016-07-01

    We adopt an optical approach in order to model and predict the spectral signature of an infrared focal plane array. The modeling is based on a multilayer description of the structure and considers a one-dimensional propagation. It provides a better understanding of the physical phenomena occurring within the pixels, which is useful to perform radiometric measurements, as well as to reliably predict the spectral sensitivity of the detector. An exhaustive model is presented, covering the total spectral range of the pixel response. A heuristic model is also described, depicting a complementary approach that separates the different optical phenomena inside the pixel structure. Promising results are presented, validating the models through comparison with experimental results. Finally, advantages and limitations of this approach are discussed.

  7. Planck 2015 results. XII. Full focal plane simulations

    Science.gov (United States)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bock, J. J.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bucher, M.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Castex, G.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H. C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dolag, K.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Ghosh, T.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Karakci, A.; Keihänen, E.; Keskitalo, R.; Kiiveri, K.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; Lindholm, V.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; McGehee, P.; Meinhold, P. R.; Melchiorri, A.; Melin, J.-B.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Roman, M.; Rosset, C.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Spencer, L. D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; Welikala, N.; Yvon, D.; Zacchei, A.; Zonca, A.

    2016-09-01

    We present the 8th full focal plane simulation set (FFP8), deployed in support of the Planck 2015 results. FFP8 consists of 10 fiducial mission realizations reduced to 18 144 maps, together with the most massive suite of Monte Carlo realizations of instrument noise and CMB ever generated, comprising 104 mission realizations reduced to about 106 maps. The resulting maps incorporate the dominant instrumental, scanning, and data analysis effects, and the remaining subdominant effects will be included in future updates. Generated at a cost of some 25 million CPU-hours spread across multiple high-performance-computing (HPC) platforms, FFP8 is used to validate and verify analysis algorithms and their implementations, and to remove biases from and quantify uncertainties in the results of analyses of the real data.

  8. Implementation of a 4x8 NIR and CCD Mosaic Focal Plane Technology

    Science.gov (United States)

    Jelinsky, Patrick; Bebek, C. J.; Besuner, R. W.; Haller, G. M.; Harris, S. E.; Hart, P. A.; Heetderks, H. D.; Levi, M. E.; Maldonado, S. E.; Roe, N. A.; Roodman, A. J.; Sapozhnikov, L.

    2011-01-01

    Mission concepts for NASA's Wide Field Infrared Survey Telescope (WFIRST), ESA's EUCLID mission, as well as for ground based observations, have requirements for large mosaic focal planes to image visible and near infrared (NIR) wavelengths. We have developed detectors, readout electronics and focal plane design techniques that can be used to create very large scalable focal plane mosaic cameras. In our technology, CCDs and HgCdTe detectors can be intermingled on a single, silicon carbide (SiC) cold plate. This enables optimized, wideband observing strategies. The CCDs, developed at Lawrence Berkeley National Laboratory, are fully-depleted, p-channel devices that are backside illuminated capable of operating at temperatures as low as 110K and have been optimized for the weak lensing dark energy technique. The NIR detectors are 1.7µm and 2.0µm wavelength cutoff H2RG® HgCdTe, manufactured by Teledyne Imaging Sensors under contract to LBL. Both the CCDs and NIR detectors are packaged on 4-side abuttable SiC pedestals with a common mounting footprint supporting a 44.16mm mosaic pitch and are coplanar. Both types of detectors have direct-attached, readout electronics that convert the detector signal directly to serial, digital data streams and allow a flexible, low cost data acquisition strategy, despite the large data volume. A mosaic of these detectors can be operated at a common temperature that achieves the required dark current and read noise performance in both types of detectors necessary for dark energy observations. We report here the design and integration for a focal plane designed to accommodate a 4x8 heterogeneous array of CCDs and HgCdTe detectors. Our current implementation contains over 1/4-billion pixels.

  9. Focal-Plane Arrays of Quantum-Dot Infrared Photodetectors

    Science.gov (United States)

    Gunapala, Sarath; Wilson, Daniel; Hill, Cory; Liu, John; Bandara, Sumith; Ting, David

    2007-01-01

    Focal-plane arrays of semiconductor quantum-dot infrared photodetectors (QDIPs) are being developed as superior alternatives to prior infrared imagers, including imagers based on HgCdTe devices and, especially, those based on quantum-well infrared photodetectors (QWIPs). HgCdTe devices and arrays thereof are difficult to fabricate and operate, and they exhibit large nonunformities and high 1/f (where f signifies frequency) noise. QWIPs are easier to fabricate and operate, can be made nearly uniform, and exhibit lower 1/f noise, but they exhibit larger dark currents, and their quantization only along the growth direction prevents them from absorbing photons at normal incidence, thereby limiting their quantum efficiencies. Like QWIPs, QDIPs offer the advantages of greater ease of operation, greater uniformity, and lower 1/f noise, but without the disadvantages: QDIPs exhibit lower dark currents, and quantum efficiencies of QDIPs are greater because the three-dimensional quantization of QDIPs is favorable to the absorption of photons at normal or oblique incidence. Moreover, QDIPs can be operated at higher temperatures (around 200 K) than are required for operation of QWIPs. The main problem in the development of QDIP imagers is to fabricate quantum dots with the requisite uniformity of size and spacing. A promising approach to be tested soon involves the use of electron-beam lithography to define the locations and sizes of quantum dots. A photoresist-covered GaAs substrate would be exposed to the beam generated by an advanced, high-precision electron beam apparatus. The exposure pattern would consist of spots typically having a diameter of 4 nm and typically spaced 20 nm apart. The exposed photoresist would be developed by either a high-contrast or a low-contrast method. In the high-contrast method, the spots would be etched in such a way as to form steep-wall holes all the way down to the substrate. The holes would be wider than the electron beam spots perhaps as

  10. Focal plane wavefront sensor achromatization : The multireference self-coherent camera

    CERN Document Server

    Delorme, J -R; Baudoz, P; Rousset, G; Mazoyer, J; Dupuis, O

    2016-01-01

    High contrast imaging and spectroscopy provide unique constraints for exoplanet formation models as well as for planetary atmosphere models. But this can be challenging because of the planet-to-star small angular separation and high flux ratio. Recently, optimized instruments like SPHERE and GPI were installed on 8m-class telescopes. These will probe young gazeous exoplanets at large separations (~1au) but, because of uncalibrated aberrations that induce speckles in the coronagraphic images, they are not able to detect older and fainter planets. There are always aberrations that are slowly evolving in time. They create quasi-static speckles that cannot be calibrated a posteriori with sufficient accuracy. An active correction of these speckles is thus needed to reach very high contrast levels (>1e7). This requires a focal plane wavefront sensor. Our team proposed the SCC, the performance of which was demonstrated in the laboratory. As for all focal plane wavefront sensors, these are sensitive to chromatism and...

  11. FOCAL PLANE WAVEFRONT SENSING USING RESIDUAL ADAPTIVE OPTICS SPECKLES

    Energy Technology Data Exchange (ETDEWEB)

    Codona, Johanan L.; Kenworthy, Matthew, E-mail: jlcodona@gmail.com [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2013-04-20

    Optical imperfections, misalignments, aberrations, and even dust can significantly limit sensitivity in high-contrast imaging systems such as coronagraphs. An upstream deformable mirror (DM) in the pupil can be used to correct or compensate for these flaws, either to enhance the Strehl ratio or suppress the residual coronagraphic halo. Measurement of the phase and amplitude of the starlight halo at the science camera is essential for determining the DM shape that compensates for any non-common-path (NCP) wavefront errors. Using DM displacement ripples to create a series of probe and anti-halo speckles in the focal plane has been proposed for space-based coronagraphs and successfully demonstrated in the lab. We present the theory and first on-sky demonstration of a technique to measure the complex halo using the rapidly changing residual atmospheric speckles at the 6.5 m MMT telescope using the Clio mid-IR camera. The AO system's wavefront sensor measurements are used to estimate the residual wavefront, allowing us to approximately compute the rapidly evolving phase and amplitude of speckle halo. When combined with relatively short, synchronized science camera images, the complex speckle estimates can be used to interferometrically analyze the images, leading to an estimate of the static diffraction halo with NCP effects included. In an operational system, this information could be collected continuously and used to iteratively correct quasi-static NCP errors or suppress imperfect coronagraphic halos.

  12. Focal Plane Wavefront Sensing using Residual Adaptive Optics Speckles

    CERN Document Server

    Codona, Johanan L

    2013-01-01

    Optical imperfections, misalignments, aberrations, and even dust can significantly limit sensitivity in high-contrast imaging systems such as coronagraphs. An upstream deformable mirror (DM) in the pupil can be used to correct or compensate for these flaws, either to enhance Strehl ratio or suppress residual coronagraphic halo. Measurement of the phase and amplitude of the starlight halo at the science camera is essential for determining the DM shape that compensates for any non-common-path (NCP) wavefront errors. Using DM displacement ripples to create a series of probe and anti-halo speckles in the focal plane has been proposed for space-based coronagraphs and successfully demonstrated in the lab. We present the theory and first on-sky demonstration of a technique to measure the complex halo using the rapidly-changing residual atmospheric speckles at the 6.5m MMT telescope using the Clio mid-IR camera. The AO system's wavefront sensor (WFS) measurements are used to estimate the residual wavefront, allowing ...

  13. A CMOS Imager with Focal Plane Compression using Predictive Coding

    Science.gov (United States)

    Leon-Salas, Walter D.; Balkir, Sina; Sayood, Khalid; Schemm, Nathan; Hoffman, Michael W.

    2007-01-01

    This paper presents a CMOS image sensor with focal-plane compression. The design has a column-level architecture and it is based on predictive coding techniques for image decorrelation. The prediction operations are performed in the analog domain to avoid quantization noise and to decrease the area complexity of the circuit, The prediction residuals are quantized and encoded by a joint quantizer/coder circuit. To save area resources, the joint quantizerlcoder circuit exploits common circuitry between a single-slope analog-to-digital converter (ADC) and a Golomb-Rice entropy coder. This combination of ADC and encoder allows the integration of the entropy coder at the column level. A prototype chip was fabricated in a 0.35 pm CMOS process. The output of the chip is a compressed bit stream. The test chip occupies a silicon area of 2.60 mm x 5.96 mm which includes an 80 X 44 APS array. Tests of the fabricated chip demonstrate the validity of the design.

  14. Intelligent sensors research using pulse-coupled neural networks for focal plane image processing

    Science.gov (United States)

    Tarr, Gregory L.; Carreras, Richard A.; DeHainaut, Christopher R.; Clastres, Xavier; Freyss, Laurent; Samuelides, Manuel

    1996-03-01

    An important difference between biological vision systems and their electronic counterparts is the large number of feedback signals controlling each aspect of the image collection process. For every forward path of information in the brain, from sensor to comprehension, there appears to be several neural bundles which send information back to the sensor to modify the way the information is collected. In this paper we will examine the role of such feedback signals and suggest algorithms for intelligent processing of images directly on the focal plane, using feedback. We consider first what form these signals might take and how they can be used to implement functions common to conventional image processing with the objective of moving the computation out of the digital domain and place much of its on the focal plane, or analog processing close to the focal plane. While this work falls under the general heading of artificial neural networks, it goes beyond the static processing of signals suggested by the McCulloch and Pitts model of the neuron and the Laplacian image processing suggested by Carver Mead by including the dynamics of temporal encoding in the analysis process.

  15. Liquid crystal microlens with tunable-focus over focal plane driven by low-voltage signal

    Science.gov (United States)

    Kang, Shengwu; Rong, Xing; Zhang, Xinyu; Xie, Changsheng; Zhang, Tianxu

    2012-11-01

    A liquid crystal (LC) microlens with a new type of electrode pattern is designed. The both bottom and top ITO electrodes of LC microlens are placed face to face, and are separated by glass spacer with the thickness in micron scale, and then LC materials are injected into the cell constructed by them. Because of the two electrodes directly and closely facing the LC layer injected, the design can largely decrease the driving signal voltage for LC lens. The bottom electrode is designed with one round hole pattern. The top electrode is four circle patterns. The diameters of round hole and circle are 500μm and 160μm, respectively. Each circle pattern electrode can be used to focus incident light into different region over the focal plane of LC lens. When the four circle electrodes are driven by different signal at the same time, the focus can be moved off-axis over the focal plane of LC lens, and thus the voltage amplitude can be varied in the range from 0Vrms to 20Vrms. So, we realize a LC microlens with tunable-focus over the focal plane of LC lens driven by low-amplitude voltage signal.

  16. Synthesis of fully continuous phase screens for tailoring the focal plane irradiance profiles

    Energy Technology Data Exchange (ETDEWEB)

    Dixit, S.; Feit, M.

    1996-04-26

    We present an iterative procedure for constructing fully continuous phase screens for tailoring the focal plane intensity distributions. This algorithm alleviates the stagnations experienced in the application of the Gerchberg-Saxton algorithm with a random initial phase screen and leads to efficient distribution of the incident energy into the desired focal plane profile.

  17. System and method for generating a deselect mapping for a focal plane array

    Science.gov (United States)

    Bixler, Jay V; Brandt, Timothy G; Conger, James L; Lawson, Janice K

    2013-05-21

    A method for generating a deselect mapping for a focal plane array according to one embodiment includes gathering a data set for a focal plane array when exposed to light or radiation from a first known target; analyzing the data set for determining which pixels or subpixels of the focal plane array to add to a deselect mapping; adding the pixels or subpixels to the deselect mapping based on the analysis; and storing the deselect mapping. A method for gathering data using a focal plane array according to another embodiment includes deselecting pixels or subpixels based on a deselect mapping; gathering a data set using pixels or subpixels in a focal plane array that are not deselected upon exposure thereof to light or radiation from a target of interest; and outputting the data set.

  18. Detectors and Focal Plane Modules for Weather Satellites

    Science.gov (United States)

    D'Souza, A. I.; Robinson, E.; Masterjohn, S.; Ely, P.; Khalap, V.; Babu, S.; Smith, D. S.

    2016-01-01

    Weather satellite instruments require detectors with a variety of wavelengths ranging from the visible to VLWIR. One of the remote sensing applications is the geostationary GOES-ABI imager covering wavelengths from the 450 to 490 nm band through the 13.0 to 13.6 micron band. There are a total of 16 spectral bands covered. The Cross-track infrared Sounder (CrIS) is a Polar Orbiting interferometric sensor that measures earth radiances at high spectral resolution, using the data to provide pressure, temperature and moisture profiles of the atmosphere. The pressure, temperature and moisture sounding data are used in weather prediction models that track storms, predict levels of precipitation etc. The CrIS instrument contains SWIR (lamba(sub c) approximately 5 micron at 98K), MWIR (lambda(sub c) approximately 9 micron at 98K) and LWIRs (lamba(sub c) approximately 15.5 micron at 81K) bands in three Focal Plane Array Assemblies (FPAAs). GOES-ABI contains three focal plane modules (FPMs), (i) a visible-near infrared module consisting of three visible and three near infrared channels, (ii) a MWIR module comprised of five channels from 3.9 micron to 8.6 micron and (iii) a 9.6 micron to 13.3 micron, five-channel LWIR module. The VNIR FPM operates at 205 K, and the MWIR and LWIR FPMs operate at 60 K. Each spectral channel has a redundant array built into a single detector chip. Switching is thus permitted from the primary selected array in each channel to the redundant array, given any degradation in performance of the primary array during the course of the mission. Silicon p-i-n detectors are used for the 0.47 micron to 0.86 micron channels. The thirteen channels above 1 micron are fabricated in various compositions of Hg1-xCdxTe, and in this particular case using two different detector architectures. The 1.38 micron to 9.61 micron channels are all fabricated in Hg1-xCdxTe grown by Liquid Phase Epitaxy (LPE) using the HDVIP detector architecture. Molecular beam epitaxy (MBE

  19. Detectors and Focal Plane Modules for Weather Instruments

    Science.gov (United States)

    D'Souza, A.I.; Robinson, E.; Masterjohn, S.; Khalap, V.; Bhargava, S.; Rangel, E.; Babu, S.; Smith, D. S.

    2016-01-01

    Weather satellite instruments require detectors with a variety of wavelengths ranging from the visible to VLWIR. The Cross-track infrared Sounder (CrIS) is a Polar Orbiting interferometric sensor that measures earth radiances at high spectral resolution, using the data to provide pressure, temperature and moisture profiles of the atmosphere. The pressure, temperature and moisture sounding data are used in weather prediction models that track storms, predict levels of precipitation etc. The CrIS instrument contains SWIR (lambda(sub c) (is) approximately 5 micrometers at 98 K), MWIR (lambda(sub c) (is) approximately 9 micrometers at 98 K) and LWIRs (lambda(sub c) (is) approximately 15.4 ?m at 81 K) bands in three Focal Plane Array Assemblies (FPAAs). CrIS detectors are 850 micrometers diameter detectors with each FPAA consisting of nine photovoltaic detectors arranged in a 3 x 3 pattern. Molecular beam epitaxy (MBE)-grown Hg1-xCdxTe material are used for the detectors fabricated in a modified Double Layer Planar Heterostructure (DLPH) architecture. Each detector has an accompanying cold preamplifier. SWIR and MWIR FPAAs operate at 98 K and the LWIR FPAA at 81 K, permitting the use of passive radiators to cool the detectors. D* requirements at peak 14.01 micrometers wavelength are greater than 5.0E+10 Jones for LWIR, greater than 7.5E+10 Jones at 8.26 micrometers for MWIR and greater than 3.0E+11 Jones at peak 4.64 micrometers wavelength for SWIR. All FPAAs exceeded the D* requirements. Measured mean values for the nine photodiodes in each of the LWIR, MWIR and SWIR FPAAs are D* = 5.3 x 10(exp 10) cm-Hz1/2/W at 14.0 micrometers, 9.6 x 10(exp 10) cm-Hz1/2/W at 8.0 micrometers and 3.4 x 10(exp 11) cm-Hz1/2/W at 4.64 micrometers.

  20. Detectors and focal plane modules for weather instruments

    Science.gov (United States)

    D'Souza, A. I.; Robinson, E.; Masterjohn, S.; Khalap, V.; Bhargava, S.; Rangel, E.; Babu, S.; Smith, D. S.

    2016-05-01

    Weather satellite instruments require detectors with a variety of wavelengths ranging from the visible to VLWIR. The Cross-track infrared Sounder (CrIS) is a Polar Orbiting interferometric sensor that measures earth radiances at high spectral resolution, using the data to provide pressure, temperature and moisture profiles of the atmosphere. The pressure, temperature and moisture sounding data are used in weather prediction models that track storms, predict levels of precipitation etc. The CrIS instrument contains SWIR (λc ~ 5 μm at 98 K), MWIR (λc ~ 9 μm at 98 K) and LWIRs (λc ~ 15.4 μm at 81 K) bands in three Focal Plane Array Assemblies (FPAAs). CrIS detectors are 850 μm diameter detectors with each FPAA consisting of nine photovoltaic detectors arranged in a 3 x 3 pattern. Molecular beam epitaxy (MBE)-grown Hg1-xCdxTe material are used for the detectors fabricated in a modified Double Layer Planar Heterostructure (DLPH) architecture. Each detector has an accompanying cold preamplifier. SWIR and MWIR FPAAs operate at 98 K and the LWIR FPAA at 81 K, permitting the use of passive radiators to cool the detectors. D* requirements at peak 14.01 μm wavelength are >= 5.0E+10 Jones for LWIR, >= 7.5E+10 Jones at 8.26 μm for MWIR and >= 3.0E+11 Jones at peak 4.64 μm wavelength for SWIR. All FPAAs exceeded the D* requirements. Measured mean values for the nine photodiodes in each of the LWIR, MWIR and SWIR FPAAs are D* = 5.3 x 1010 cm-Hz1/2/W at 14.0 μm, 9.6 x 1010 cm-Hz1/2/W at 8.0 μm and 3.4 x 1011 cm-Hz1/2/W at 4.64 μm.

  1. Technology for advanced focal plane arrays of HgCdTe and AIGaN

    CERN Document Server

    He, Li; Ni, Guoqiang

    2016-01-01

    This book introduces the basic framework of advanced focal plane technology based on the third-generation infrared focal plane concept. The essential concept, research advances, and future trends in advanced sensor arrays are comprehensively reviewed. Moreover, the book summarizes recent research advances in HgCdTe/AlGaN detectors for the infrared/ultraviolet waveband, with a particular focus on the numerical method of detector design, material epitaxial growth and processing, as well as Complementary Metal-Oxide-Semiconductor Transistor readout circuits. The book offers a unique resource for all graduate students and researchers interested in the technologies of focal plane arrays or electro-optical imaging sensors.

  2. A 260 megapixel visible/NIR mixed technology focal plane for space

    Science.gov (United States)

    Besuner, Robert W.; Bebek, Christopher J.; Haller, Gunther M.; Harris, Stewart E.; Hart, Philip A.; Heetderks, Henry D.; Jelinsky, Patrick N.; Lampton, Michael L.; Levi, Michael E.; Maldonado, Sergio E.; Roe, Natalie A.; Roodman, Aaron J.; Sapozhnikov, Leonid

    2011-10-01

    Mission concepts for NASA's Wide Field Infrared Survey Telescope (WFIRST)1,2, ESA's Euclid3,4 mission, as well as next-generation ground-based surveys require large mosaic focal planes sensitive in both visible and near infrared (NIR) wavelengths. We have developed space-qualified detectors, readout electronics and focal plane design techniques that can be used to intermingle CCDs and NIR detectors on a single, silicon carbide (SiC) cold plate. This enables optimized, wideband observing strategies. The CCDs, developed at Lawrence Berkeley National Laboratory, are fully-depleted, pchannel devices that are backside illuminated and capable of operating at temperatures down to 120K. The NIR detectors are 1.7 μm and 2.0 μm wavelength cutoff H2RG® HgCdTe, manufactured by Teledyne Imaging Sensors under contract to LBNL. Both the CCDs and NIR detectors are packaged on 4-side abuttable SiC pedestals with a common mounting footprint supporting a 44 mm mosaic pitch. Both types of detectors have direct-attached readout electronics that convert the detector signal directly to serial, digital data streams and allow a flexible, low cost data acquisition strategy to enable large data rates. A mosaic of these detectors can be operated at a common temperature that achieves the required dark current and read noise performance necessary for dark energy observations. We report here the qualification testing and performance verification for a focal plane that accommodates a 4x8 array of CCDs and HgCdTe detectors.

  3. A DSP-based Readout and Online Processing System for a new Focal-plane Polarimeter at AGOR

    NARCIS (Netherlands)

    Hagemann, M; Bassini, R; van den Berg, AM; Ellinghaus, F; Frekers, D; Hannen, VM; Haupke, T; Heyse, J; Jacobs, E; Kirsch, M; Krusemann, B; Sohlbach, H; Wortche, HJ

    1999-01-01

    A Focal-Plane Polarimeter (FPP) for the large acceptance Big-Bite Spectrometer (BBS) at AGOR using a novel readout architecture has been commissioned at the KVI Groningen. The instrument is optimized for medium-energy polarized proton scattering near or at 0 degrees. For the handling of the high

  4. Leaky Lens Based UWB Focal Plane Arrays for Sub-mm Wave Imaging Based on Kinetic Inductance Detectors

    NARCIS (Netherlands)

    Neto, A.

    2008-01-01

    A novel strategy for broad band focal plane array design is proposed. Its purpose is to couple the radiation from a Large FID reflector system to an array of Kinetic Inductance detectors that are being investigated and realized at SRON. To maximize the benefits from using their BW properties the ide

  5. In-line X-slot element focal plane array of kinetic inductance detectors

    NARCIS (Netherlands)

    Iacono, A.; Freni, A.; Neto, A.; Gerini, G.

    2011-01-01

    Kinetic Inductance Detectors are very promising THz imaging devices to be used in Focal Plane Array configuration. In this work a new antenna feed element has been studied and optimized. Preliminary results on array configuration are also shown.

  6. High Resolution, Radiation Tolerant Focal Plane Array for Lunar And Deep Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aerius Photonics and its partners propose the development of a high resolution, radiation hardened 3-D FLASH Focal Plane Array (FPA), with performance expected to be...

  7. Beam control for LINC-NIRVANA: from the binocular entrance pupil to the combined focal plane

    Science.gov (United States)

    Bertram, T.; Trowitzsch, J.; Herbst, T. M.; Ragazzoni, R.

    2012-07-01

    LINC-NIRVANA is the near-infrared interferometric imaging camera for the Large Binocular Telescope. Once operational, it will provide an unprecedented combination of angular resolution, sensitivity and field of view. To meet the tight requirements that result from long exposure interferometric imaging over a large field of view, active control beyond fringe tracking and adaptive optics has to be in place in the telescope and in the instrument domain. The incoming beams of the binocular telescope have to be controlled along the entire optical path, from the entrance pupil to the combined focal plane. The beams have to coincide in the focal plane of the science detector, their pointing origins, offsets, orientations, plate scales, and distortions have to match each other and must not change during the observation. Non-common path effects between AO and science channel, flexure and thermal effects have to be compensated and offioading requests from the adaptive optics and fringe tracking systems have to be arbitrated without introducing unwanted optical path length differences or changes in the geometry of the binocular entrance pupil. Beam Control aspects include pointing, co-pointing and field derotation, active optics and collimation control. In this presentation, the constraints for coherent imaging over a 1.5 arcminute field of view are discussed together with a concept for a distributed control scheme.

  8. Focal plane detector for QDD spectrography in Institute of Nuclear Study and detector for SMART 2nd focal plane in RIKEN

    Energy Technology Data Exchange (ETDEWEB)

    Fuchi, Yoshihide [Tokyo Univ., Tanashi (Japan). Inst. for Nuclear Study

    1996-09-01

    The focal plane detector for QDD spectrography in Institute of Nuclear Study was composed of drift space and a proportional counter tube, and the latter is composed of position detector and two delta E detector for recognizing the particles. In this detector, a uniform parallel electric field can be obtained by placing a guard plate at the same height as that of a drift plate outer place of the detector. On the other hand, the detector for SMART 2nd focal plate in RIKEN is composed of drift space and a single wire proportional counter, and has two cathode read out single wire drift counters set so as to hold the focal plane. (G.K.)

  9. Terahertz 3D printed diffractive lens matrices for field-effect transistor detector focal plane arrays.

    Science.gov (United States)

    Szkudlarek, Krzesimir; Sypek, Maciej; Cywiński, Grzegorz; Suszek, Jarosław; Zagrajek, Przemysław; Feduniewicz-Żmuda, Anna; Yahniuk, Ivan; Yatsunenko, Sergey; Nowakowska-Siwińska, Anna; Coquillat, Dominique; But, Dmytro B; Rachoń, Martyna; Węgrzyńska, Karolina; Skierbiszewski, Czesław; Knap, Wojciech

    2016-09-05

    We present the concept, the fabrication processes and the experimental results for materials and optics that can be used for terahertz field-effect transistor detector focal plane arrays. More specifically, we propose 3D printed arrays of a new type - diffractive multi-zone lenses of which the performance is superior to that of previously used mono-zone diffractive or refractive elements and evaluate them with GaN/AlGaN field-effect transistor terahertz detectors. Experiments performed in the 300-GHz atmospheric window show that the lens arrays offer both a good efficiency and good uniformity, and may improve the signal-to-noise ratio of the terahertz field-effect transistor detectors by more than one order of magnitude. In practice, we tested 3 × 12 lens linear arrays with printed circuit board THz detector arrays used in postal security scanners and observed significant signal-to-noise improvements. Our results clearly show that the proposed technology provides a way to produce cost-effective, reproducible, flat optics for large-size field-effect transistor THz-detector focal plane arrays.

  10. On-focal-plane superconducting signal processing for low- and intermediate-temperature operation

    Science.gov (United States)

    Smetana, Daryl L.; Carson, John C.

    1991-11-01

    The marriage of superconducting electronics with Z-plane FPA readout structures offer the potential for high speed, low power parallel digital processing on-focal plane. This paper reports on some early research into this marriage of two technologies conducted by Irvine Sensors Corporation (ISC) and TRW. Progress is reviewed for both low and high temperature superconducting technologies.

  11. A superconducting focal plane array for ultraviolet, optical, and near-infrared astrophysics

    CERN Document Server

    Mazin, Benjamin A; Meeker, Seth R; O'Brien, Kieran; McHugh, Sean; Langman, Eric

    2011-01-01

    Microwave Kinetic Inductance Detectors, or MKIDs, have proven to be a powerful cryogenic detector technology due to their sensitivity and the ease with which they can be multiplexed into large arrays. A MKID is an energy sensor based on a photon-variable superconducting inductance in a lithographed microresonator, and is capable of functioning as a photon detector across the electromagnetic spectrum as well as a particle detector. Here we describe the first successful effort to create a photon-counting, energy-resolving ultraviolet, optical, and near infrared MKID focal plane array. These new Optical Lumped Element (OLE) MKID arrays have significant advantages over semiconductor detectors like charge coupled devices (CCDs). They can count individual photons with essentially no false counts and determine the energy and arrival time of every photon with good quantum efficiency. Their physical pixel size and maximum count rate is well matched with large telescopes. These capabilities enable powerful new astrophy...

  12. Fabrication of a Cryogenic Bias Filter for Ultrasensitive Focal Plane

    Science.gov (United States)

    Chervenak, James; Wollack, Edward

    2012-01-01

    A fabrication process has been developed for cryogenic in-line filtering for the bias and readout of ultrasensitive cryogenic bolometers for millimeter and submillimeter wavelengths. The design is a microstripline filter that cuts out, or strongly attenuates, frequencies (10 50 GHz) that can be carried by wiring staged at cryogenic temperatures. The filter must have 100-percent transmission at DC and low frequencies where the bias and readout lines will carry signal. The fabrication requires the encapsulation of superconducting wiring in a dielectric-metal envelope with precise electrical characteristics. Sufficiently thick insulation layers with high-conductivity metal layers fully surrounding a patterned superconducting wire in arrayable formats have been demonstrated. A degenerately doped silicon wafer has been chosen to provide a metallic ground plane. A metallic seed layer is patterned to enable attachment to the ground plane. Thick silicon dioxide films are deposited at low temperatures to provide tunable dielectric isolation without degrading the metallic seed layer. Superconducting wiring is deposited and patterned using microstripline filtering techniques to cut out the relevant frequencies. A low Tc superconductor is used so that it will attenuate power strongly above the gap frequency. Thick dielectric is deposited on top of the circuit, and then vias are patterned through both dielectric layers. A thick conductive film is deposited conformally over the entire circuit, except for the contact pads for the signal and bias attachments to complete the encapsulating ground plane. Filters are high-aspect- ratio rectangles, allowing close packing in one direction, while enabling the chip to feed through the wall of a copper enclosure. The chip is secured in the copper wall using a soft metal seal to make good thermal and electrical contact to the outer shield.

  13. Multiple detector focal plane array ultraviolet spectrometer for the AMPS laboratory

    Science.gov (United States)

    Feldman, P. D.

    1975-01-01

    The possibility of meeting the requirements of the amps spectroscopic instrumentation by using a multi-element focal plane detector array in a conventional spectrograph mount was examined. The requirements of the detector array were determined from the optical design of the spectrometer which in turn depends on the desired level of resolution and sensitivity required. The choice of available detectors and their associated electronics and controls was surveyed, bearing in mind that the data collection rate from this system is so great that on-board processing and reduction of data are absolutely essential. Finally, parallel developments in instrumentation for imaging in astronomy were examined, both in the ultraviolet (for the Large Space Telescope as well as other rocket and satellite programs) and in the visible, to determine what progress in that area can have direct bearing on atmospheric spectroscopy.

  14. The self-coherent camera as a focal plane fine phasing sensor

    CERN Document Server

    Janin-Potiron, Pierre; Baudoz, Pierre; Carbillet, Marcel

    2016-01-01

    Direct imaging of Earth-like exoplanets requires high contrast imaging capability and high angular resolution. Primary mirror segmentation is a key technological solution for large-aperture telescopes because it opens the path toward significantly increasing the angular resolution. The segments are kept aligned by an active optics system that must reduce segment misalignments below tens of nm RMS to achieve the high optical quality required for astronomical science programs. The development of cophasing techniques is mandatory for the next generation of space- and ground-based segmented telescopes, which both share the need for increasing spatial resolution. We propose a new focal plane cophasing sensor that exploits the scientific image of a coronagraphic instrument to retrieve simultaneously piston and tip-tilt misalignments. The self-coherent camera phasing sensor (SCC-PS) adequately combines the SCC properties to segmented telescope architectures with adapted segment misalignment estimators and image proc...

  15. New CMOS readout circuit with background suppression and CDS for infrared focal plane array applications

    Institute of Scientific and Technical Information of China (English)

    LI Xin-yi; ZHAO Yi-qiang; YAO Su-ying

    2009-01-01

    A high injection, large dynamic range, stable detector bias, small area and low power consumption CMOS readout circuit with background current suppression and correlated double sampling (CDS) for a high-resolution infrared focal plane array applications is proposed. The detector bias error in this structure is less than 0.1 mV. The input resistance is ideally zero, which is important to obtain high injection efficiency. Unit-cell occupies 10 μm × 15 μm area and consumes less than 0.4 mW power. Charge storage capacity is 3 × 108 electrons. The function and performance of the proposed readout circuit have been verified by experimental results.

  16. Fabrication of Transition Edge Sensor Microcalorimeters for X-Ray Focal Planes

    Science.gov (United States)

    Chervenak, James A.; Adams, Joseph S.; Audley, Heather; Bandler, Simon R.; Betancourt-Martinez, Gabriele; Eckart, Megan E.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline; Lee, Sang Jun; Mateo, Jennette; Sadleir, John E.; Smith, Stephen J.; Wassell, Edward; Yoon, Wonsik

    2015-01-01

    Requirements for focal planes for x-ray astrophysics vary widely depending on the needs of the science application such as photon count rate, energy band, resolving power, and angular resolution. Transition edge sensor x-ray calorimeters can encounter limitations when optimized for these specific applications. Balancing specifications leads to choices in, for example, pixel size, thermal sinking arrangement, and absorber thickness and material. For the broadest specifications, instruments can benefit from multiple pixel types in the same array or focal plane. Here we describe a variety of focal plane architectures that anticipate science requirements of x-ray instruments for heliophysics and astrophysics. We describe the fabrication procedures that enable each array and explore limitations for the specifications of such arrays, including arrays with multiple pixel types on the same array.

  17. Focal plane wavefront sensor achromatization: The multireference self-coherent camera

    Science.gov (United States)

    Delorme, J. R.; Galicher, R.; Baudoz, P.; Rousset, G.; Mazoyer, J.; Dupuis, O.

    2016-04-01

    Context. High contrast imaging and spectroscopy provide unique constraints for exoplanet formation models as well as for planetary atmosphere models. But this can be challenging because of the planet-to-star small angular separation (105). Recently, optimized instruments like VLT/SPHERE and Gemini/GPI were installed on 8m-class telescopes. These will probe young gazeous exoplanets at large separations (≳1 au) but, because of uncalibrated phase and amplitude aberrations that induce speckles in the coronagraphic images, they are not able to detect older and fainter planets. Aims: There are always aberrations that are slowly evolving in time. They create quasi-static speckles that cannot be calibrated a posteriori with sufficient accuracy. An active correction of these speckles is thus needed to reach very high contrast levels (>106-107). This requires a focal plane wavefront sensor. Our team proposed a self coherent camera, the performance of which was demonstrated in the laboratory. As for all focal plane wavefront sensors, these are sensitive to chromatism and we propose an upgrade that mitigates the chromatism effects. Methods: First, we recall the principle of the self-coherent camera and we explain its limitations in polychromatic light. Then, we present and numerically study two upgrades to mitigate chromatism effects: the optical path difference method and the multireference self-coherent camera. Finally, we present laboratory tests of the latter solution. Results: We demonstrate in the laboratory that the multireference self-coherent camera can be used as a focal plane wavefront sensor in polychromatic light using an 80 nm bandwidth at 640 nm (bandwidth of 12.5%). We reach a performance that is close to the chromatic limitations of our bench: 1σ contrast of 4.5 × 10-8 between 5 and 17 λ0/D. Conclusions: The performance of the MRSCC is promising for future high-contrast imaging instruments that aim to actively minimize the speckle intensity so as to

  18. Optimized focal and pupil plane masks for vortex coronagraphs on telescopes with obstructed apertures

    Science.gov (United States)

    Ruane, Garreth J.; Absil, Olivier; Huby, Elsa; Mawet, Dimitri; Delacroix, Christian; Carlomagno, Brunella; Piron, Pierre; Swartzlander, Grover A.

    2015-09-01

    We present methods for optimizing pupil and focal plane optical elements that improve the performance of vortex coronagraphs on telescopes with obstructed or segmented apertures. Phase-only and complex masks are designed for the entrance pupil, focal plane, and the plane of the Lyot stop. Optimal masks are obtained using both analytical and numerical methods. The latter makes use of an iterative error reduction algorithm to calculate "correcting" optics that mitigate unwanted diffraction from aperture obstructions. We analyze the achieved performance in terms of starlight suppression, contrast, off-axis image quality, and chromatic dependence. Manufacturing considerations and sensitivity to aberrations are also discussed. This work provides a path to joint optimization of multiple coronagraph planes to maximize sensitivity to exoplanets and other faint companions.

  19. Optimized focal and pupil plane masks for vortex coronagraphs on telescopes with obstructed apertures

    CERN Document Server

    Ruane, Garreth J; Huby, Elsa; Mawet, Dimitri; Delacroix, Christian; Carlomagno, Brunella; Piron, Pierre; Swartzlander, Grover A

    2015-01-01

    We present methods for optimizing pupil and focal plane optical elements that improve the performance of vortex coronagraphs on telescopes with obstructed or segmented apertures. Phase-only and complex masks are designed for the entrance pupil, focal plane, and the plane of the Lyot stop. Optimal masks are obtained using both analytical and numerical methods. The latter makes use of an iterative error reduction algorithm to calculate "correcting" optics that mitigate unwanted diffraction from aperture obstructions. We analyze the achieved performance in terms of starlight suppression, contrast, off-axis image quality, and chromatic dependence. Manufacturing considerations and sensitivity to aberrations are also discussed. This work provides a path to joint optimization of multiple coronagraph planes to maximize sensitivity to exoplanets and other faint companions.

  20. A new monolithic approach for mid-IR focal plane arrays

    Science.gov (United States)

    Xie, Chengzhi; Pusino, Vincenzo; Khalid, Ata; Aziz, Mohsin; Steer, Matthew J.; Cumming, David R. S.

    2016-10-01

    Antimonide-based photodetectors have recently been grown on a GaAs substrate by molecular beam epitaxy (MBE) and reported to have comparable performance to the devices grown on more expensive InSb and GaSb substrates. We demonstrated that GaAs, in addition to providing a cost saving substrate for antimonide-based semiconductor growth, can be used as a functional material to fabricate transistors and realize addressing circuits for the heterogeneously grown photodetectors. Based on co-integration of a GaAs MESFET with an InSb photodiode, we recently reported the first demonstration of a switchable and mid-IR sensible photo-pixel on a GaAs substrate that is suitable for large-scale integration into a focal plane array. In this work we report on the fabrication steps that we had to develop to deliver the integrated photo-pixel. Various highly controllable etch processes, both wet and dry etch based, were established for distinct material layers. Moreover, in order to avoid thermally-induced damage to the InSb detectors, a low temperature annealed Ohmic contact was used, and the processing temperature never exceeded 180 °C. Furthermore, since there is a considerable etch step (> 6 μm) that metal must straddle in order to interconnect the fabricated devices, we developed an intermediate step using polyimide to provide a smoothing section between the lower MESFET and upper photodiode regions of the device. This heterogeneous technology creates great potential to realize a new type of monolithic focal plane array of addressable pixels for imaging in the medium wavelength infrared range without the need for flip-chip bonding to a CMOS readout chip.

  1. Radionuclide imaging with coded apertures and three-dimensional image reconstruction from focal-plane tomography

    Energy Technology Data Exchange (ETDEWEB)

    Chang, L.T.

    1976-05-01

    Two techniques for radionuclide imaging and reconstruction have been studied;; both are used for improvement of depth resolution. The first technique is called coded aperture imaging, which is a technique of tomographic imaging. The second technique is a special 3-D image reconstruction method which is introduced as an improvement to the so called focal-plane tomography. (auth)

  2. Chemical imaging of cotton fibers using an infrared microscope and a focal-plane array detector

    Science.gov (United States)

    In this presentation, the chemical imaging of cotton fibers with an infrared microscope and a Focal-Plane Array (FPA) detector will be discussed. Infrared spectroscopy can provide us with information on the structure and quality of cotton fibers. In addition, FPA detectors allow for simultaneous spe...

  3. Calibrating a high-Esolution wavefront corrector with a static focal-Plane camera

    NARCIS (Netherlands)

    Korkiakoski, V.; Doelman, N.J.; Codona, J.; Kenworthy, M.; Otten, G.; Keller, C.U.

    2013-01-01

    We present a method to calibrate a high-resolution wavefront (WF)-correcting device with a single, static camera, located in the focal-plane; no moving of any component is needed. The method is based on a localized diversity and differential optical transfer functions to compute both the phase and a

  4. A focal plane detector design for a wide-band Laue-lens telescope

    DEFF Research Database (Denmark)

    Caroli, E.; Auricchio, N.; Amati, L.

    2005-01-01

    , and the detection of nuclear and annihilation lines. Recently the development of high energy Laue lenses with broad energy bandpasses from 60 to 600 keV have been proposed for a Hard X ray focusing Telescope (HAXTEL) in order to study the X-ray continuum of celestial sources. The required focal plane detector...

  5. Statistical framework for the utilization of simultaneous pupil plane and focal plane telemetry for exoplanet imaging. I. Accounting for aberrations in multiple planes.

    Science.gov (United States)

    Frazin, Richard A

    2016-04-01

    A new generation of telescopes with mirror diameters of 20 m or more, called extremely large telescopes (ELTs), has the potential to provide unprecedented imaging and spectroscopy of exoplanetary systems, if the difficulties in achieving the extremely high dynamic range required to differentiate the planetary signal from the star can be overcome to a sufficient degree. Fully utilizing the potential of ELTs for exoplanet imaging will likely require simultaneous and self-consistent determination of both the planetary image and the unknown aberrations in multiple planes of the optical system, using statistical inference based on the wavefront sensor and science camera data streams. This approach promises to overcome the most important systematic errors inherent in the various schemes based on differential imaging, such as angular differential imaging and spectral differential imaging. This paper is the first in a series on this subject, in which a formalism is established for the exoplanet imaging problem, setting the stage for the statistical inference methods to follow in the future. Every effort has been made to be rigorous and complete, so that validity of approximations to be made later can be assessed. Here, the polarimetric image is expressed in terms of aberrations in the various planes of a polarizing telescope with an adaptive optics system. Further, it is shown that current methods that utilize focal plane sensing to correct the speckle field, e.g., electric field conjugation, rely on the tacit assumption that aberrations on multiple optical surfaces can be represented as aberration on a single optical surface, ultimately limiting their potential effectiveness for ground-based astronomy.

  6. Focal plane actuation to achieve ultra-high resolution on suborbital balloon payloads

    Science.gov (United States)

    Scowen, Paul A.; Miller, Alex; Challa, Priya; Veach, Todd; Groppi, Chris; Mauskopf, Phil

    2014-07-01

    Over the past few years there has been remarkable success flying imaging telescope systems suspended from suborbital balloon payload systems. These imaging systems have covered optical, ultraviolet, sub-­-millimeter and infrared passbands (i.e. BLAST, STO, SBI, Fireball and others). In recognition of these advances NASA is now considering ambitious programs to promote planetary imaging from high altitude at a fraction of the cost of similar fully orbital systems. The challenge with imaging from a balloon payload is delivering the full diffraction-­-limited resolution of the system from a moving payload. Good progress has been made with damping mechanisms and oscillation control to remove most macroscopic movement in the departures of the imaging focal plane from a static configuration, however a jitter component remains that is difficult to remove using external corrections. This paper reports on work to demonstrate in the laboratory the utility and performance of actuating a detector focal plane (of whatever type) to remove the final jitter terms using an agile hexapod design. The input to this demonstration is the jitter signal generated by the pointing system of a previously flown balloon mission (the Stratospheric Terahertz Observatory, STO). Our group has a mature jitter compensation system that thermally isolates the control head from the focal plane itself. This allows the hexapod to remain at ambient temperature in a vacuum environment with the focal plane cooled to cryogenic temperatures. Our lab design mounts the focal plane on the hexapod in a custom cryostat and delivers an active optical stimulus together with the corresponding jitter signal, using the actuation of the hexapod to correct for the departures from a static, stable configuration. We believe this demonstration will make the case for inclusion of this technological solution in future balloon-­-borne imaging systems requiring ultra-­-high resolution.

  7. SWIR InGaAs focal plane arrays in France

    Science.gov (United States)

    Rouvié, A.; Huet, O.; Hamard, S.; Truffer, J. P.; Pozzi, M.; Decobert, J.; Costard, E.; Zécri, M.; Maillart, P.; Reibel, Y.; Pécheur, A.

    2013-06-01

    SWIR detection band benefits from natural (sun, night glow, thermal radiation) or artificial (eye safe lasers) photons sources combined to low atmospheric absorption and specific contrast compared to visible wavelengths. It gives the opportunity to address a large spectrum of applications such as defense and security (night vision, active imaging), space (earth observation), transport (automotive safety) or industry (non destructive process control). InGaAs material appears as a good candidate to satisfy SWIR detection needs. The lattice matching with InP constitutes a double advantage to this material: attractive production capacity and uncooled operation thanks to low dark current level induced by high quality material. The study of InGaAs FPA has begun few years ago with III-VLab, gathering expertise in InGaAs material growth and imaging technology respectively from Alcatel-Lucent and Thales, its two mother companies. This work has led to put quickly on the market a 320x256 InGaAs module. The recent transfer of imagery activities from III-VLab to Sofradir allows developing new high performances products, satisfying customers' new requirements. Especially, a 640x512 InGaAs module with a pitch of 15µm is actually under development to fill the needs of low light level imaging.

  8. Polarization dOTF: on-sky focal plane wavefront sensing

    CERN Document Server

    Brooks, Keira J; Kenworthy, Matthew A; Crawford, Steven M; Codona, Johanan L

    2016-01-01

    The differential Optical Transfer Function (dOTF) is a focal plane wavefront sensing method that uses a diversity in the pupil plane to generate two different focal plane images. The difference of their Fourier transforms recovers the complex amplitude of the pupil down to the spatial scale of the diversity. We produce two simultaneous PSF images with diversity using a polarizing filter at the edge of the telescope pupil, and a polarization camera to simultaneously record the two images. Here we present the first on-sky demonstration of polarization dOTF at the 1.0m South African Astronomical Observatory telescope in Sutherland, and our attempt to validate it with simultaneous Shack-Hartmann wavefront sensor images.

  9. WSPEC: A waveguide filter-bank focal plane array spectrometer for millimeter wave astronomy and cosmology

    CERN Document Server

    Bryan, Sean; Che, George; Doyle, Simon; Flanigan, Daniel; Groppi, Christopher; Johnson, Bradley; Jones, Glenn; Mauskopf, Philip; McCarrick, Heather; Monfardini, Alessandro; Mroczkowski, Tony

    2015-01-01

    Imaging and spectroscopy at (sub-)millimeter wavelengths are key frontiers in astronomy and cosmology. Large area spectral surveys with moderate spectral resolution (R=50-200) will be used to characterize large scale structure and star formation through intensity mapping surveys in emission lines such as the CO rotational transitions. Such surveys will also be used to study the SZ effect, and will detect the emission lines and continuum spectrum of individual objects. WSPEC is an instrument proposed to target these science goals. It is a channelizing spectrometer realized in rectangular waveguide, fabricated using conventional high-precision metal machining. Each spectrometer is coupled to free space with a machined feed horn, and the devices are tiled into a 2D array to fill the focal plane of the telescope. The detectors will be aluminum Lumped-Element Kinetic Inductance Detectors (LEKIDs). To target the CO lines and SZ effect, we will have bands at 135-175 GHz and 190-250 GHz, each Nyquist-sampled at R~200...

  10. A superconducting focal plane array for ultraviolet, optical, and near-infrared astrophysics.

    Science.gov (United States)

    Mazin, Benjamin A; Bumble, Bruce; Meeker, Seth R; O'Brien, Kieran; McHugh, Sean; Langman, Eric

    2012-01-16

    Microwave Kinetic Inductance Detectors, or MKIDs, have proven to be a powerful cryogenic detector technology due to their sensitivity and the ease with which they can be multiplexed into large arrays. A MKID is an energy sensor based on a photon-variable superconducting inductance in a lithographed microresonator, and is capable of functioning as a photon detector across the electromagnetic spectrum as well as a particle detector. Here we describe the first successful effort to create a photon-counting, energy-resolving ultraviolet, optical, and near infrared MKID focal plane array. These new Optical Lumped Element (OLE) MKID arrays have significant advantages over semiconductor detectors like charge coupled devices (CCDs). They can count individual photons with essentially no false counts and determine the energy and arrival time of every photon with good quantum efficiency. Their physical pixel size and maximum count rate is well matched with large telescopes. These capabilities enable powerful new astrophysical instruments usable from the ground and space. MKIDs could eventually supplant semiconductor detectors for most astronomical instrumentation, and will be useful for other disciplines such as quantum optics and biological imaging.

  11. WSPEC: A Waveguide Filter-Bank Focal Plane Array Spectrometer for Millimeter Wave Astronomy and Cosmology

    Science.gov (United States)

    Bryan, Sean; Aguirre, James; Che, George; Doyle, Simon; Flanigan, Daniel; Groppi, Christopher; Johnson, Bradley; Jones, Glenn; Mauskopf, Philip; McCarrick, Heather; Monfardini, Alessandro; Mroczkowski, Tony

    2016-07-01

    Imaging and spectroscopy at (sub-)millimeter wavelengths are key frontiers in astronomy and cosmology. Large area spectral surveys with moderate spectral resolution (R=50-200) will be used to characterize large-scale structure and star formation through intensity mapping surveys in emission lines such as the CO rotational transitions. Such surveys will also be used to study the the Sunyaev Zeldovich (SZ) effect, and will detect the emission lines and continuum spectrum of individual objects. WSPEC is an instrument proposed to target these science goals. It is a channelizing spectrometer realized in rectangular waveguide, fabricated using conventional high-precision metal machining. Each spectrometer is coupled to free space with a machined feed horn, and the devices are tiled into a 2D array to fill the focal plane of the telescope. The detectors will be aluminum lumped-element kinetic inductance detectors (LEKIDs). To target the CO lines and SZ effect, we will have bands at 135-175 and 190-250 GHz, each Nyquist-sampled at R≈ 200 resolution. Here, we discuss the instrument concept and design, and successful initial testing of a WR10 (i.e., 90 GHz) prototype spectrometer. We recently tested a WR5 (180 GHz) prototype to verify that the concept works at higher frequencies, and also designed a resonant backshort structure that may further increase the optical efficiency. We are making progress towards integrating a spectrometer with a LEKID array and deploying a prototype device to a telescope for first light.

  12. High contrast imaging through adaptive transmittance control in the focal plane

    Science.gov (United States)

    Dhadwal, Harbans S.; Rastegar, Jahangir; Feng, Dake

    2016-05-01

    High contrast imaging, in the presence of a bright background, is a challenging problem encountered in diverse applications ranging from the daily chore of driving into a sun-drenched scene to in vivo use of biomedical imaging in various types of keyhole surgeries. Imaging in the presence of bright sources saturates the vision system, resulting in loss of scene fidelity, corresponding to low image contrast and reduced resolution. The problem is exacerbated in retro-reflective imaging systems where the light sources illuminating the object are unavoidably strong, typically masking the object features. This manuscript presents a novel theoretical framework, based on nonlinear analysis and adaptive focal plane transmittance, to selectively remove object domain sources of background light from the image plane, resulting in local and global increases in image contrast. The background signal can either be of a global specular nature, giving rise to parallel illumination from the entire object surface or can be represented by a mosaic of randomly orientated, small specular surfaces. The latter is more representative of real world practical imaging systems. Thus, the background signal comprises of groups of oblique rays corresponding to distributions of the mosaic surfaces. Through the imaging system, light from group of like surfaces, converges to a localized spot in the focal plane of the lens and then diverges to cast a localized bright spot in the image plane. Thus, transmittance of a spatial light modulator, positioned in the focal plane, can be adaptively controlled to block a particular source of background light. Consequently, the image plane intensity is entirely due to the object features. Experimental image data is presented to verify the efficacy of the methodology.

  13. Focal-plane CMOS wavelet feature extraction for real-time pattern recognition

    Science.gov (United States)

    Olyaei, Ashkan; Genov, Roman

    2005-09-01

    Kernel-based pattern recognition paradigms such as support vector machines (SVM) require computationally intensive feature extraction methods for high-performance real-time object detection in video. The CMOS sensory parallel processor architecture presented here computes delta-sigma (ΔΣ)-modulated Haar wavelet transform on the focal plane in real time. The active pixel array is integrated with a bank of column-parallel first-order incremental oversampling analog-to-digital converters (ADCs). Each ADC performs distributed spatial focal-plane sampling and concurrent weighted average quantization. The architecture is benchmarked in SVM face detection on the MIT CBCL data set. At 90% detection rate, first-level Haar wavelet feature extraction yields a 7.9% reduction in the number of false positives when compared to classification with no feature extraction. The architecture yields 1.4 GMACS simulated computational throughput at SVGA imager resolution at 8-bit output depth.

  14. Quantitative Characterization of Super-Resolution Infrared Imaging Based on Time-Varying Focal Plane Coding

    Science.gov (United States)

    Wang, X.; Yuan, Y.; Zhang, J.; Chen, Y.; Cheng, Y.

    2014-10-01

    High resolution infrared image has been the goal of an infrared imaging system. In this paper, a super-resolution infrared imaging method using time-varying coded mask is proposed based on focal plane coding and compressed sensing theory. The basic idea of this method is to set a coded mask on the focal plane of the optical system, and the same scene could be sampled many times repeatedly by using time-varying control coding strategy, the super-resolution image is further reconstructed by sparse optimization algorithm. The results of simulation are quantitatively evaluated by introducing the Peak Signal-to-Noise Ratio (PSNR) and Modulation Transfer Function (MTF), which illustrate that the effect of compressed measurement coefficient r and coded mask resolution m on the reconstructed image quality. Research results show that the proposed method will promote infrared imaging quality effectively, which will be helpful for the practical design of new type of high resolution ! infrared imaging systems.

  15. Physics with a focal plane proton polarimeter for hall A at CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, R. [Continuous Electron Beam Accelerator Facility, Newport News, Virginia 23606 (United States)]|[Rutgers University, Piscataway, New Jersey 08855 (United States); Baker, F.T. [University of Georgia, Athens, Georgia 30602 (United States); Bimbot, L. [Rutgers University, Piscataway, New Jersey 08855 (United States); Brash, E. [College of William and Mary, Williamsburg, Virginia 23187 (United States); Glashausser, C. [Rutgers University, Piscataway, New Jersey 08855 (United States); Jones, M. [College of William and Mary, Williamsburg, Virginia 23187 (United States); Kumbartzki, G. [Rutgers University, Piscataway, New Jersey 08855 (United States); Nanda, S. [Continuous Electron Beam Accelerator Facility, Newport News, Virginia 23606 (United States); Perdrisat, C. [College of William and Mary, Williamsburg, Virginia 23187 (United States); Punjabi, V. [Norfolk State University, Norfolk, Virginia 23504 (United States); Ransome, R. [Rutgers University, Piscataway, New Jersey 08855 (United States); Rutt, P. [Rutgers University, Piscataway, New Jersey 08855 (United States)]|[University of Georgia, Athens, Georgia 30602 (United States)

    1995-09-01

    A focal plane polarimeter intended for the CEBAF Hall A high resolution hadron spectrometer is under construction at Rutgers University and the College of William and Mary. Experiments with focal plane polarimeters are only now beginning at electron accelerators; they play a prominent role in the list of approved experiments for Hall A. Construction of the polarimeter is in progress, it is expected to be brought to CEBAF in spring 1995. Several coincidence (e,e{prime}{bar p}) and singles ({gamma},{bar p}) measurements by the Hall A Collaboration are expected to start in 1996. In this paper we describe the polarimeter and the physics program planned for it. {copyright} {ital 1995 American Institute of Physics.}

  16. Focal-Plane Imaging of Crossed Beams in Nonlinear Optics Experiments

    Science.gov (United States)

    Bivolaru, Daniel; Herring, G. C.

    2007-01-01

    An application of focal-plane imaging that can be used as a real time diagnostic of beam crossing in various optical techniques is reported. We discuss two specific versions and demonstrate the capability of maximizing system performance with an example in a combined dual-pump coherent anti-Stokes Raman scattering interferometric Rayleigh scattering experiment (CARS-IRS). We find that this imaging diagnostic significantly reduces beam alignment time and loss of CARS-IRS signals due to inadvertent misalignments.

  17. Focal Plane Array Sensor for Imaging Infrared Seeker of Antitank Guided Missile

    Directory of Open Access Journals (Sweden)

    A.V.R. Warrier

    1995-07-01

    Full Text Available Technological issues and Processes for fabrication of mercury cadmium telluride detector arrays, charge coupled device readout arrays and integration of these into a focal plane array sensor have been discussed. Mini arrays of 16 X 16 size have been realised and tested to prove the technology and process schedule with a view to scaling up this for larger arrays to be used in the antitank guided missile.

  18. 128 x 128 MWIR InSb focal plane and camera system

    Science.gov (United States)

    Parrish, William J.; Blackwell, John D.; Paulson, Robert C.; Arnold, Harold

    1991-09-01

    The need for increased resolution and sensitivity in IR systems applications has provided the impetus for the development of high-performance second-generation staring focal plane array technology. Previously, the availability of these focal plane array components has been limited and the costs associated with delivery of useful hardware have been high. Utilizing proven InSb detector technology and foundry silicon CMOS processes, a high performance, affordable hybrid focal plane array and support electronics system has been developed. The 128 X 128 array of photovoltac InSb detectors on 50 micrometers centers is interfaced with the silicon readout by aligning and cold welding indium bumps on each detector with the corresponding indium bump on the silicon readout. The detector is then thinned so that it can be illuminated through the backside. The 128 X 128 channel signal processing integrated circuit performs the function of interfacing with the detectors, integrating the detector current, and multiplexing the signals. It is fabricated using a standard double poly, single metal, p-well CMOS process. The detector elements achieve a high quantum efficiency response from less than 1 micrometers to greater than 5 micrometers with an optical fill factor of 90%. The hybrid focal plane array can operate to a maximum frame rate of 1,000 Hz. D* values at 1.7 X 1014 photons/cm2/sec illumination conditions approach the BLIP value of 9.4 X 1011 cm(root)Hz/W with a capacity of 4 X 107 carriers and a dynamic range of greater than 60,000. A NE(Delta) T value of .018 C and a MRT value of .020 C have been measured. The devices operate with only 3 biases and 3 clocks.

  19. Self-Calibration Method Based on Surface Micromaching of Light Transceiver Focal Plane for Optical Camera

    Directory of Open Access Journals (Sweden)

    Jin Li

    2016-10-01

    Full Text Available In remote sensing photogrammetric applications, inner orientation parameter (IOP calibration of remote sensing camera is a prerequisite for determining image position. However, achieving such a calibration without temporal and spatial limitations remains a crucial but unresolved issue to date. The accuracy of IOP calibration methods of a remote sensing camera determines the performance of image positioning. In this paper, we propose a high-accuracy self-calibration method without temporal and spatial limitations for remote sensing cameras. Our method is based on an auto-collimating dichroic filter combined with a surface micromachining (SM point-source focal plane. The proposed method can autonomously complete IOP calibration without the need of outside reference targets. The SM procedure is used to manufacture a light transceiver focal plane, which integrates with point sources, a splitter, and a complementary metal oxide semiconductor sensor. A dichroic filter is used to fabricate an auto-collimation light reflection element. The dichroic filter, splitter, and SM point-source focal plane are integrated into a camera to perform an integrated self-calibration. Experimental measurements confirm the effectiveness and convenience of the proposed method. Moreover, the method can achieve micrometer-level precision and can satisfactorily complete real-time calibration without temporal or spatial limitations.

  20. Design of corrugated-horn-coupled MKID focal plane for CMB B-mode polarization

    Science.gov (United States)

    Sekimoto, Yutaro; Sekiguchi, Shigeyuki; Shu, Shibo; Sekine, Masakazu; Nitta, Tom; Naruse, Masato; Dominjon, Agnes; Hasebe, Takashi; Shan, Wenlei; Noguchi, Takashi; Miyachi, Akihira; Mita, Makoto; Kawasaki, Shigeo

    2016-07-01

    A focal plane based on MKID has been designed for cosmic microwave background (CMB) B-mode polarization experiments. We are designing and developing a focal plane with broadband corrugated horn array, planar OMT, 180 degree hybrid, bandpass filters, and MKIDs. The focal plane consists of 3 octave bands (55 - 108 GHz, 80 - 160 GHz, 160 - 320 GHz), 10 hexagonal modules. Broadband corrugated horn-array has been directly machined from an Al block and measured to have a good beam shape which is consistent with electromagnetic field simulations in octave bands. The horn array is designed to be low standing-wave, light weight, and electromagnetic shield. The broadband 4 probes ortho-mode transducer (OMT) is fabricated on Si membrane of an SOI wafer. A broadband 180 degree hybrid made with coplanar waveguide (CPW) is used to reduce higher modes of the circular waveguide. Two bandpass filters of each polarization are patterned with Nb microstrip. A prototype of the broadband corrugated horn coupled MKIDs has been fabricated and tested.

  1. a computational modeling for image motion velocity on focal plane of aerial & aerospace frame camera

    Science.gov (United States)

    Zhang, X.; Jin, G.; Li, Z. Y.

    As the resolving power and geometric accuracy of aerial aerospace imaging is demanded to be higher the researches in technology of IMC become very important In order to compensate the image motion on focal plane the rule of FPIMV Focal Plane Image Motion Velocity should be grasped while the posture of aircraft and the modes of imaging are under changing In this paper a reasonable computational modeling scheme to the problem is introduced Coordinates transformation method is utilized for calculation of forward FPIMV under different condition of vertical and sloped imaging meanwhile integrated with three axes posture and angle velocity of aircraft Forward FPIMV combine with pitch roll and yaw FPIMV is considered simultaneously and the derivation calculating expressions of frame camera FPIMV under different conditions is presented in detail The solution is applied to computational simulation and has been confirmed to be effective based on the calculation result and it lays the foundation for our farther researches on frame camera IMC technology Key words IMC FPIMV Focal Plane Image Motion Velocity Coordinates transformation method

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

    Science.gov (United States)

    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.

  3. A DSP-based readout and online processing system for a new focal-plane polarimeter at AGOR

    Energy Technology Data Exchange (ETDEWEB)

    Hagemann, M.; Bassini, R.; Berg, A.M. van den; Ellinghaus, F.; Frekers, D.; Hannen, V.M.; Haeupke, T.; Heyse, J.; Jacobs, E.; Kirsch, M.; Kruesemann, B.; Rakers, S.; Sohlbach, H.; Woertche, H.J. E-mail: wortche@ikp.uni-muenster.de

    1999-11-21

    A Focal-Plane Polarimeter (FPP) for the large acceptance Big-Bite Spectrometer (BBS) at AGOR using a novel readout architecture has been commissioned at the KVI Groningen. The instrument is optimized for medium-energy polarized proton scattering near or at 0 deg. . For the handling of the high counting rates at extreme forward angles and for the suppression of small-angle scattering in the graphite analyzer, a high-performance data processing DSP system connecting to the LeCroy FERA and PCOS ECL bus architecture has been made operational and tested successfully. Details of the system and the functions of the various electronic components are described.

  4. Long Focal Length Large Mirror Fabrication System

    Science.gov (United States)

    Bennett, H. E.

    2003-01-01

    The goals of this ambitious program are (1) to develop systems to make large superpolished optical mirrors, (2) to develop low scatter polishing techniques using centrifugal elutriation, (3) to develop a means of measuring scatter at any point on the mirror, (4) to polish a Hindle sphere to measure the optical figure of a one meter diameter convex mandrel, and (5) to fabricate low scatter, large adaptive optic graphite filled, cyanate ester replica transfer mirrors using these mandrels. Deliverables are a 30 cm diameter superpolished composite AO mirror. We fabricated a 1/3rd meter superpolished zerodur flat mandrel and with the support of our major subcontractor, Composite Mirror Applications Inc (CMA) we have demonstrated a 30 cm lightweight cyanate ester mirror with an rms microroughness between 0.6 and 0.8 nm and 8 faceplate influence function of 5 cm. The influence function was chosen to be comparable to the atmospheric correlation coefficient r(sub 0) which is about 5 cm at sea level. There was no print-thru of the graphite fibers in the cyanate ester surface (the bane of many previous efforts to use cyanate ester mirrors). Our subcontractor has devised a means for developing a 30-50 nm thick layer of graphite free pure ester resin on the surface of the mirrors. This graphite fiber filled material has a thermal expansion coefficient in the 10(exp -8) centimeter per Kelvin range (the same range of expansion coefficient as Zerodur and ULE glasses) and does not take up water and swell, so it is a nearly ideal mirror material in these areas. Unfortunately for these 0.8mm thick faceplates, the number of plies is not enough to result in isometric coverage. Isolated figure irregularities can appear, making it necessary to go to thicker faceplates. The influence function will then only approximate the length of r(sub 0), at higher altitudes or longer wavelengths. The influence function goes as the cube of the thickness, so we are now making a faceplate optimized for

  5. Analysis of receiving sensitivity of multi-beam antenna systems with a focal plane array (in Russian)

    CERN Document Server

    Iupikov, O

    2016-01-01

    In this paper, we present a numerical electromagnetic model of a focal plane array in combination with a multi-channel receiver. Initial experimental validation results are shown that confirm the expected predictions from the model.

  6. Photonic antenna enhanced middle wave and longwave infrared focal plane array with low noise and high operating temperature Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Photodetectors and focal plane arrays (FPAs) covering the middle-wave and longwave infrared (MWIR/LWIR) are of great importance in numerous NASA applications,...

  7. Dualband MW/LW Strained Layer Superlattice Focal Plane Arrays For Satellite-Based Wildfire Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Dualband focal plane arrays (FPAs) based on gallium-free Type-II strained layer superlattice (SLS) photodiodes have recently experienced significant advances. We...

  8. Polarimeter on a Chip: Antenna-Coupled Microbolometers and Polarimeters for Submillimeterwave and Millimeterwave Focal Planes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future missions to study astrophysical sources at millimeter and submillimeter wavelengths require focal planes of 1000's of detectors that must operate at the...

  9. The self-coherent camera as a focal plane fine phasing sensor

    Science.gov (United States)

    Janin-Potiron, P.; Martinez, P.; Baudoz, P.; Carbillet, M.

    2016-08-01

    Context. Direct imaging of Earth-like exoplanets requires very high contrast imaging capability and high angular resolution. Primary mirror segmentation is a key technological solution for large-aperture telescopes because it opens the path toward significantly increasing the angular resolution. The segments are kept aligned by an active optics system that must reduce segment misalignments below tens of nm rms to achieve the high optical quality required for astronomical science programs. Aims: The development of cophasing techniques is mandatory for the next generation of space- and ground-based segmented telescopes, which both share the need for increasing spatial resolution. We propose a new focal plane cophasing sensor that exploits the scientific image of a coronagraphic instrument to retrieve simultaneously piston and tip-tilt misalignments. Methods: The self-coherent camera phasing sensor (SCC-PS) adequately combines the SCC properties to segmented telescope architectures with adapted segment misalignment estimators and image processing. An overview of the system architecture, and a thorough performance and sensitivity analysis, including a closed-loop efficiency, are presented by means of numerical simulations. Results: The SCC-PS estimates simultaneously piston and tip-tilt misalignments and corrects them in closed-loop operation in a few iterations. As opposed to numerous phasing sensor concepts the SCC-PS does not require any a priori on the signal at the segment boundaries or any dedicated optical path. We show that the SCC-PS has a moderate sensitivity to misalignments, virtually none to pupil shear, and is by principle insensitive to segment gaps and edge effects. Primary mirror phasing can be achieved with a relatively bright natural guide star with the SCC-PS. Conclusions: The SCC-PS is a noninvasive concept and an efficient phasing sensor from the image domain. It is an attractive candidate for segment cophasing at the instrument level or

  10. An uncooled microbolometer focal plane array using heating based resistance nonuniformity compensation

    Science.gov (United States)

    Tepegoz, Murat; Oguz, Alp; Toprak, Alperen; Senveli, S. Ufuk; Canga, Eren; Tanrikulu, M. Yusuf; Akin, Tayfun

    2012-06-01

    This paper presents the performance evaluation of a unique method called heating based resistance nonuniformity compensation (HB-RNUC). The HB-RNUC method utilizes a configurable bias heating duration for each pixel in order to minimize the readout integrated circuit (ROIC) output voltage distribution range. The outputs of each individual pixel in a resistive type microbolometer differ from each other by a certain amount due to the resistance non-uniformity throughout the focal plane array (FPA), which is an inevitable result of the microfabrication process. This output distribution consumes a considerable portion of the available voltage headroom of the ROIC unless compensated properly. The conventional compensation method is using on-chip DACs to apply specific bias voltages to each pixel such that the output distribution is confined around a certain point. However, on-chip DACs typically occupy large silicon area, increase the output noise, and consume high power. The HB-RNUC method proposes modifying the resistances of the pixels instead of the bias voltages, and this task can be accomplished by very simple circuit blocks. The simplicity of the required blocks allows utilizing a low power, low noise, and high resolution resistance nonuniformity compensation operation. A 9-bit HB-RNUC structure has been designed, fabricated, and tested on a 384x288 microbolometer FPA ROIC on which 35μm pixel size detectors are monolithically implemented, in order to evaluate its performance. The compensation operation reduces the standard deviation of the ROIC output distribution from 470 mV to 9 mV under the same readout gain and bias settings. The analog heating channels of the HB-RNUC block dissipate around 4.1 mW electrical power in this condition, and the increase in the output noise due to these blocks is lower than 10%.

  11. Testing System Based on Virtual Instrument for Readout Circuit of Infrared Focal Plane Array

    Institute of Scientific and Technical Information of China (English)

    XUE Lian; MENG Li-ya; YUAN Xiang-hui

    2008-01-01

    Readout integrated circuit(ROIC) is one of the most important components for hybrid-integrated infrared focal plane array(IRFPA). And it should be tested to ensure the product yield before bonding. This paper presents an on-wafer testing system based on Labview for ROIC of IRFPA. The quantitative measurement can be conducted after determining whether there is row crosstalk or not in this system. This low-cost system has the benefits of easy expansion, upgrading, and flexibility, and it has been employed in the testing of several kinds of IRFPA ROICs to measure the parameters of saturated output voltage, non-uniformity, dark noise and dynamic range, etc.

  12. Extended short-wavelength spectral response from InGaAs focal plane arrays

    Science.gov (United States)

    Hoelter, Theodore R.; Barton, Jeffrey B.

    2003-09-01

    InGaAs detector material used in near infrared focal plane arrays (NIR FPAs) has typically been limited in spectral response to a range from approximately 900 nm to 1700 nm. Through special processing techniques, the spectral response can be extended down through the visible spectrum and into the ultraviolet. Test results showing preliminary spectral response from 350nm to 1700 nm, responsivity, sensitivity, corrected uniformity and simultaneous imaging of NIR and visible signals will be presented along with a discussion of anticipated applications for this new sensor technology.

  13. QWIP focal plane array theoretical model of 3-D imaging LADAR system

    OpenAIRE

    El Mashade, Mohamed Bakry; AbouElez, Ahmed Elsayed

    2016-01-01

    The aim of this research is to develop a model for the direct detection three-dimensional (3-D) imaging LADAR system using Quantum Well Infrared Photodetector (QWIP) Focal Plane Array (FPA). This model is employed to study how to add 3-D imaging capability to the existing conventional thermal imaging systems of the same basic form which is sensitive to 3–5 mm (mid-wavelength infrared, MWIR) or 8–12 mm (long-wavelength infrared, LWIR) spectral bands. The integrated signal photoelectrons in cas...

  14. Upgrade of the TAMU MDM-focal plane detector with MicroMegas technology

    Energy Technology Data Exchange (ETDEWEB)

    Spiridon, A., E-mail: aspiridon@comp.tamu.edu [Cyclotron Institute, Texas A& M University, College Station, TX 77843 (United States); Pollacco, E. [IRFU, CEA Saclay, Gif-sur-Yvette (France); Roeder, B.T.; Saastamoinen, A.; Chyzh, R.; Dag, M.; Tribble, R.E. [Cyclotron Institute, Texas A& M University, College Station, TX 77843 (United States); Trache, L.; Pascovici, G. [National Institute of Physics and Nuclear Engineering, Bucharest-Magurele RO-077125 (Romania); De Oliveira, R. [CERN, Geneva (Switzerland)

    2016-06-01

    A gridded ionization chamber used as a focal plane detector at the back of the TAMU-MDM spectrometer was modified to use MicroMegas technology for the purpose of improving energy resolution and particle identification. The upgraded system was tested in experimental conditions with several heavy-ion beams at 12 MeV/u and found to achieve resolutions between 3.2% and 4.8%. This is a significant improvement over the previous performance of 10–15% obtained using the existing, conventional ionization chambers.

  15. A Method to Measure the Flatness of the LSST Focal Plane Assembly in Situ

    CERN Document Server

    Langeveld, W

    2005-01-01

    In this note I describe an inexpensive and simple laser-based method to measure the flatness of the LSST focal plane assembly (FPA) in situ, i.e. while the FPA is inside its cryostat, at -100 C and under vacuum. The method may also allow measurement of the distance of the FPA to lens L3, and may be sensitive enough to measure gravity- and pressure-induced deformations of L3 as well. The accuracy of the method shows promise to be better than 1 micron.

  16. Focal-plane optimization for detector noise limited performance in cryogenic Fourier transform spectrometer /FTS/ sensors

    Science.gov (United States)

    Mcguirk, M.; Logan, L.

    1980-01-01

    A study was performed to determine the optimum focal plane configuration including optics, filters and detector-preamplifier selection. The configuration was optimized particularly with respect to minimizing the noise level, but fabrication considerations for a cryogenic environment were also taken into account. The noise terms from source, background, detector electronics and charged particle radiation were quantitatively evaluated. It appears that noise equivalent spectral radiance less than 10 to the -11th W/sq cm per sr per kayser can be achieved between 2.5 and 20 microns.

  17. The investigation of properties of short-lived SF isotopes (Z > 100 at the focal plane of VASSILISSA separator

    Directory of Open Access Journals (Sweden)

    Svirikhin Alexandr

    2013-12-01

    Full Text Available For experiments aimed at the study of spontaneous fission of transfermium nuclei improvements in the focal plane detector system of recoil separator VASSILISSA have been made. A neutron detector consisting of 54 3He-filled counters has been mounted around the focal-plane detector chamber. The reaction 48Ca + 206Pb = 2n + 252No is used for tuning the separator settings and calibrating the detector system with the spontaneous fission of the 252No. The average neutron number per 252No spontaneous fission event is as large as ν̅ = 4.06 ± 0.12. The short-lived heavy isotopes 244,246Fm, produced in the complete fusion reactions 40Ar + 206,208Pb, are investigated. The average number of neutrons per spontaneous fission of 244,246Fm from the experimental data were (ν̅ = 3.3 ± 0.3 and (ν̅ = 3.55 ± 0.50, respectively. Both values are determined for the first time.

  18. Effects of Non-Elevation-Focalized Linear Array Transducer on Ultrasound Plane-Wave Imaging

    Directory of Open Access Journals (Sweden)

    Congzhi Wang

    2016-11-01

    Full Text Available Plane-wave ultrasound imaging (PWUS has become an important method of ultrasound imaging in recent years as its frame rate has exceeded 10,000 frames per second, allowing ultrasound to be used for two-dimensional shear wave detection and functional brain imaging. However, compared to the traditional focusing and scanning method, PWUS images always suffer from a degradation of lateral resolution and contrast. To improve the image quality of PWUS, many different beamforming algorithms have been proposed and verified. Yet the influence of transducer structure is rarely studied. For this paper, the influence of using an acoustic lens for PWUS was evaluated. Two linear array transducers were fabricated. One was not self-focalized in the elevation direction (non-elevation-focalized transducer, NEFT; the other one was a traditional elevation-focalized transducer (EFT. An initial simulation was conducted to show the influence of elevation focusing. Then the images obtained with NEFT on a standard ultrasound imaging phantom were compared with those obtained with EFT. It was demonstrated that, in a relatively deep region, the contrast of an NEFT image is better than that of an EFT image. These results indicate that a more sophisticated design of ultrasound transducer would further improve the image quality of PWUS.

  19. Removing defocused objects from single focal plane scans of cytological slides

    Directory of Open Access Journals (Sweden)

    David Friedrich

    2016-01-01

    Full Text Available Background: Virtual microscopy and automated processing of cytological slides are more challenging compared to histological slides. Since cytological slides exhibit a three-dimensional surface and the required microscope objectives with high resolution have a low depth of field, these cannot capture all objects of a single field of view in focus. One solution would be to scan multiple focal planes; however, the increase in processing time and storage requirements are often prohibitive for clinical routine. Materials and Methods: In this paper, we show that it is a reasonable trade-off to scan a single focal plane and automatically reject defocused objects from the analysis. To this end, we have developed machine learning solutions for the automated identification of defocused objects. Our approach includes creating novel features, systematically optimizing their parameters, selecting adequate classifier algorithms, and identifying the correct decision boundary between focused and defocused objects. We validated our approach for computer-assisted DNA image cytometry. Results and Conclusions: We reach an overall sensitivity of 96.08% and a specificity of 99.63% for identifying defocused objects. Applied on ninety cytological slides, the developed classifiers automatically removed 2.50% of the objects acquired during scanning, which otherwise would have interfered the examination. Even if not all objects are acquired in focus, computer-assisted DNA image cytometry still identified more diagnostically or prognostically relevant objects compared to manual DNA image cytometry. At the same time, the workload for the expert is reduced dramatically.

  20. Closed-loop focal plane wavefront control with the SCExAO instrument

    Science.gov (United States)

    Martinache, Frantz; Jovanovic, Nemanja; Guyon, Olivier

    2016-09-01

    Aims: This article describes the implementation of a focal plane based wavefront control loop on the high-contrast imaging instrument SCExAO (Subaru Coronagraphic Extreme Adaptive Optics). The sensor relies on the Fourier analysis of conventional focal-plane images acquired after an asymmetric mask is introduced in the pupil of the instrument. Methods: This absolute sensor is used here in a closed-loop to compensate for the non-common path errors that normally affects any imaging system relying on an upstream adaptive optics system.This specific implementation was used to control low-order modes corresponding to eight zernike modes (from focus to spherical). Results: This loop was successfully run on-sky at the Subaru Telescope and is used to offset the SCExAO deformable mirror shape used as a zero-point by the high-order wavefront sensor. The paper details the range of errors this wavefront-sensing approach can operate within and explores the impact of saturation of the data and how it can be bypassed, at a cost in performance. Conclusions: Beyond this application, because of its low hardware impact, the asymmetric pupil Fourier wavefront sensor (APF-WFS) can easily be ported in a wide variety of wavefront sensing contexts, for ground- as well space-borne telescopes, and for telescope pupils that can be continuous, segmented or even sparse. The technique is powerful because it measures the wavefront where it really matters, at the level of the science detector.

  1. Closed-loop focal plane wavefront control with the SCExAO instrument

    CERN Document Server

    Martinache, Frantz; Guyon, Olivier

    2016-01-01

    This article describes the implementation of a focal plane based wavefront control loop on the high-contrast imaging instrument SCExAO (Subaru Coronagraphic Extreme Adaptive Optics). The sensor relies on the Fourier analysis of conventional focal-plane images acquired after an asymmetric mask is introduced in the pupil of the instrument. This absolute sensor is used here in a closed-loop to compensate the non-common path errors that normally affects any imaging system relying on an upstream adaptive optics system.This specific implementation was used to control low order modes corresponding to eight zernike modes (from focus to spherical). This loop was successfully run on-sky at the Subaru Telescope and is used to offset the SCExAO deformable mirror shape used as a zero-point by the high-order wavefront sensor. The paper precises the range of errors this wavefront sensing approach can operate within and explores the impact of saturation of the data and how it can be bypassed, at a cost in performance. Beyond...

  2. A focal plane detector design for a wide-band Laue-lens telescope

    CERN Document Server

    Caroli, E; Amati, L; Bezsmolnyy, Y; Budtz-Jorgensen, C; Silva, R M C; Frontera, F; Pisa, A; Del Sordo, S; Stephen, J B; Ventura, G; Caroli, Ezio; Auricchio, Natalia; Amati, Lorenzo; Bezsmolnyy, Yuriy; Budtz-Jorgensen, Carl; Silva, Rui M. Curado da; Frontera, Filippo; Pisa, Alessandro; Sordo, Stefano Del; Stephen, John B.; Ventura, Giulio

    2006-01-01

    The energy range above 60 keV is important for the study of many open problems in high energy astrophysics such as the role of Inverse Compton with respect to synchrotron or thermal processes in GRBs, non thermal mechanisms in SNR, the study of the high energy cut-offs in AGN spectra, and the detection of nuclear and annihilation lines. Recently the development of high energy Laue lenses with broad energy bandpasses from 60 to 600 keV have been proposed for a Hard X ray focusing Telescope (HAXTEL) in order to study the X-ray continuum of celestial sources. The required focal plane detector should have high detection efficiency over the entire operative range, a spatial resolution of about 1 mm, an energy resolution of a few keV at 500 keV and a sensitivity to linear polarization. We describe a possible configuration of the focal plane detector based on several CdTe/CZT pixelated layers stacked together to achieve the required detection efficiency at high energy. Each layer can operate both as a separate posit...

  3. Radiation hardening of low-noise readout integrated circuit for infrared focal plane arrays

    Science.gov (United States)

    Lee, Min Su; Lee, Yong Soo; Lee, Hee Chul

    2010-04-01

    A radiation-resistant readout integrated circuit for focal plane arrays was studied to improve the reliability of infrared image systems operating in a radioactive environment, such as in space or in the surroundings of a nuclear reactor. First, as radiation-hardened NMOSFET structure, which includes a layout modification technique, was proposed. The readout integrated circuit for infrared focal plane arrays was then designed on basis of the proposed NMOSFET layout. Commercial 0.35 um process technology was used to fabricate the proposed unit NMOSFET and the designed readout integrated circuit which is based on the proposed NMOSFET. The measured electrical characteristics of the fabricated unit NMOSFET and readout integrated circuit are in good agreement with the simulated results. For verification of the radiation tolerance, the fabricated chip was exposed to 1 Mrad (Si) of gamma radiation, which is high enough to guarantee reliable usage in space or in a very harsh radiation environment. While exposed to gamma radiation, the fabricated chip was connected to a power supply (3.3 V) for testing under the worst conditions. After being exposed to 1 Mrad of gamma radiation, the unit NMOSFET showed only a slight increment of a few picoamperes in the leakage current, and the designed readout integrated circuit showed little change at an output voltage of less than 10% of a proper output voltage. The changes in the characteristics of the unit NMOSFET and the designed readout infrared integrated circuit are at an allowable level in relation to process variation.

  4. Image interpolation and denoising for division of focal plane sensors using Gaussian processes.

    Science.gov (United States)

    Gilboa, Elad; Cunningham, John P; Nehorai, Arye; Gruev, Viktor

    2014-06-16

    Image interpolation and denoising are important techniques in image processing. These methods are inherent to digital image acquisition as most digital cameras are composed of a 2D grid of heterogeneous imaging sensors. Current polarization imaging employ four different pixelated polarization filters, commonly referred to as division of focal plane polarization sensors. The sensors capture only partial information of the true scene, leading to a loss of spatial resolution as well as inaccuracy of the captured polarization information. Interpolation is a standard technique to recover the missing information and increase the accuracy of the captured polarization information. Here we focus specifically on Gaussian process regression as a way to perform a statistical image interpolation, where estimates of sensor noise are used to improve the accuracy of the estimated pixel information. We further exploit the inherent grid structure of this data to create a fast exact algorithm that operates in ����(N(3/2)) (vs. the naive ���� (N³)), thus making the Gaussian process method computationally tractable for image data. This modeling advance and the enabling computational advance combine to produce significant improvements over previously published interpolation methods for polarimeters, which is most pronounced in cases of low signal-to-noise ratio (SNR). We provide the comprehensive mathematical model as well as experimental results of the GP interpolation performance for division of focal plane polarimeter.

  5. Multispectral Thermal Imager Optical Assembly Performance and Intergration of the Flight Focal Plane Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Blake, Dick; Byrd, Don; Christensen, Wynn; Henson, Tammy; Krumel, Les; Rappoport, William; Shen, Gon-Yen

    1999-06-08

    The Multispectral Thermal Imager Optical Assembly (OA) has been fabricated, assembled, successfully performance tested, and integrated into the flight payload structure with the flight Focal Plane Assembly (FPA) integrated and aligned to it. This represents a major milestone achieved towards completion of this earth observing E-O imaging sensor that is to be operated in low earth orbit. The OA consists of an off-axis three mirror anastigmatic (TMA) telescope with a 36 cm unobscured clear aperture, a wide-field-of-view (WFOV) of 1.82° along the direction of spacecraft motion and 1.38° across the direction of spacecraft motion. It also contains a comprehensive on-board radiometric calibration system. The OA is part of a multispectral pushbroom imaging sensor which employs a single mechanically cooled focal plane with 15 spectral bands covering a wavelength range from 0.45 to 10.7 µm. The OA achieves near diffraction-limited performance from visible to the long-wave infrared (LWIR) wavelengths. The two major design drivers for the OA are 80% enpixeled energy in the visible bands and radiometric stability. Enpixeled energy in the visible bands also drove the alignment of the FPA detectors to the OA image plane to a requirement of less than ± 20 µm over the entire visible detector field of view (FOV). Radiometric stability requirements mandated a cold Lyot stop for stray light rejection and thermal background reduction. The Lyot stop is part of the FPA assembly and acts as the aperture stop for the imaging system. The alignment of the Lyot stop to the OA drove the centering and to some extent the tilt alignment requirements of the FPA to the OA.

  6. Focal depths and fault plane solutions of earthquakes and active tectonics of the Himalaya

    Science.gov (United States)

    Baranowski, J.; Armbruster, J.; Seeber, L.; Molnar, P.

    1984-01-01

    Synthetic seismograms were compared with long-period body waves for nine earthquakes with epicenters in the Himalayan arc to determine depths of foci and to improve fault plane solutions. Focal depths are shallow (10-20 km). Inferred slip vectors are locally perpendicular to the mountain range; they plunge very gently (about 10 deg) in the eastern sections of the range and more steeply (about 25 deg) in western sections. Assuming India to be a rigid plate, the radially oriented slip vectors imply that southern Tibet extends at about half the rate of underthrusting in the Himalaya and therefore probably at about 5-10 mm/yr. The shallow depths and gentle dips of the fault planes, at least for the events in the eastern half of the range, are consistent with coherent underthrusting of the Indian plate beneath, at least, the Lesser Himalaya. The steeper dips of fault planes in the western part of the arc might reflect deformation of the overriding thrust plate or simply a steepening of the main underthrusting zone beneath the Greater Himalaya.

  7. Empirical Green's Function Approach for Utilizing Millisecond Focal and Pupil Plane Telemetry in Exoplanet Imaging

    CERN Document Server

    Frazin, Richard A

    2016-01-01

    Millisecond focal plane telemetry is now becoming practical due to a new generation of near-IR detector arrays with sub-electron noise that are capable of kHz readout rates. Combining these data with those simultaneously available from the wavefront sensing system allows the possibility of self-consistently determining the optical aberrations (the cause of quasi-static speckles) and the planetary image. This approach may be especially advantageous for finding planets within about 3 $\\lambda / D$ of the star where differential imaging is ineffective. As shown in a recent article by the author (J. Opt. Soc. Am. A., 33, 712, 2016), one must account for unknown aberrations in several non-conjugate planes of the optical system, which, in turn, requires ability to computational propagate the field between these planes. These computations are likely to be difficult to implement and expensive. Here, a far more convenient alternative based on empirical Green's functions is provided. It is shown that the empirical Gree...

  8. A novel MEMS-based focal plane array for infrared imaging

    Institute of Scientific and Technical Information of China (English)

    LI Chaobo; JIAO Binbin; SHI Shali; YE Tianchun; CHEN Dapeng; ZHANG Qingchuan; GUO Zheying; DONG Fengliang; WU Xiaoping

    2007-01-01

    On the basis of opto-mechanical effect and micro electromechanical system(MEMS)technology,a novel substrate-free focal plane array(FPA)with the thermal isolated structure for uncooled infrared imaging is developed,even as alternate evaporated Au on SiN cantilever is used for thermal isolation.A human thermal image is obtained successfully by using the infrared imaging system composed of the FPA and optical detecting system.The experiment results show that the realization of thermal isolation structure in substrate-free FPA increases the temperature rise of the deflecting leg effectively,whereas the noise equivalent temperature difierence(NETDl is about 200 mK.

  9. An innovative concept for the AsteroidFinder/SSB focal plane assembly

    CERN Document Server

    Schindler, Karsten; Koncz, Alexander; Solbrig, Michael; Michaelis, Harald

    2016-01-01

    This paper gives a summary on the system concept and design of the focal plane assembly of AsteroidFinder/SSB, a small satellite mission which is currently under development at the German Aerospace Center (DLR). An athermal design concept has been developed in accordance to the requirements of the instrument and spacecraft. Key aspects leading to this approach have been a trade-off study of the mechanical telescope interface, the definition of electrical and thermal interfaces and a material selection which minimizes thermally induced stresses. As a novelty, the structure will be manufactured from a machinable AlN-BN composite ceramic. To enable rapid design iterations and development, an integrated modeling approach has been used to conduct a thermo-mechanical analysis of the proposed concept in order to prove its feasibility. The steady-state temperature distribution for various load cases and the resulting stress and strain within the assembly have both been computed using a finite element simulation.

  10. Spatial noise limited NETD performance of a HgCdTe hybrid focal plane array

    Science.gov (United States)

    Gopal, Vishnu

    1996-04-01

    This paper presents a model for theoretically estimating the residual spatial noise in a direct injection readout hybrid focal plane array (FPA) consisting of photovoltaic detectors. The procedure consists of computing the response of the pixels after taking into account the nonlinearity induced by the transfer function in the hybrid configuration and the estimated r.m.s. response nonuniformity from the known input parameters of the detector and readout arrays. A linear two point nonuniformity compensation algorithm is applied to the computed pixel responses to calculate the residual spatial noise. Signal-to-spatial noise ratio is then used to estimate the spatial noise limited NETD performance of MWIR and LWIR Hg 1- x Cd x Te hybrid FPAs.

  11. Nonuniformity compensation methods for the thermal imager based on uncooled focal plane array

    Science.gov (United States)

    Wu, Cheng; Su, Junhong

    2000-05-01

    Because of the detector material, manufacturing technology and optical system, there is a obvious signal responsivity variation in sensor elements of uncooled focal plane array (UFPA), that is same as the cooled FPA. This variations results in a severe fixed pattern noise. There have been a lot of varied ways to compensate the nonuniformity of FPA detectors now. This paper briefly describes several main nonuniformity compensation (NUC) methods discussed below, and considering the properties of UFPA detectors, the precision and rate of NUC, a practical NUC methods applying to UFPA is given. The aim is to simplify the hardware and software of NUC for UFPA, and to satisfy the requests of use in the real world simultaneously.

  12. Radiation Channels Close to a Plasmonic Nanowire Visualized by Back Focal Plane Imaging

    Science.gov (United States)

    Hartmann, Nicolai; Piatkowski, Dawid; Ciesielski, Richard; Mackowski, Sebastian; Hartschuh, Achim

    2014-01-01

    We investigated the angular radiation patterns, a key characteristic of an emitting system, from individual silver nanowires decorated with rare earth ion-doped nanocrystals. Back focal plane radiation patterns of the nanocrystal photoluminescence after local two-photon excitation can be described by two emission channels: Excitation of propagating surface plasmons in the nanowire followed by leakage radiation and direct dipolar emission observed also in the absence of the nanowire. Theoretical modeling reproduces the observed radiation patterns which strongly depend on the position of excitation along the nanowire. Our analysis allows to estimate the branching ratio into both emission channels and to determine the diameter dependent surface plasmon quasi-momentum, important parameters of emitter-plasmon structures. PMID:24131299

  13. Complete Focal Plane Compression Based on CMOS Image Sensor Using Predictive Coding

    Institute of Scientific and Technical Information of China (English)

    Yao Suying; Yu Xiao; Gao Jing; Xu Jiangtao

    2015-01-01

    In this paper, a CMOS image sensor(CIS) is proposed, which can accomplish both decorrelation and en-tropy coding of image compression directly on the focal plane. The design is based on predictive coding for image decorrelation. The predictions are performed in analog domain by 2×2 pixel units. Both the prediction residuals and original pixel values are quantized and encoded in parallel. Since the residuals have a peak distribution around zero, the output codewords can be replaced by the valid part of the residuals’ binary mode. The compressed bit stream is accessible directly at the output of CIS without extra disposition. Simulation results show that the proposed approach achieves a compression rate of 2. 2 and PSNR of 51 on different test images.

  14. Automated alignment of a reconfigurable optical system using focal-plane sensing and Kalman filtering

    CERN Document Server

    Fang, Joyce

    2016-01-01

    Automation of alignment tasks can provide improved efficiency and greatly increase the flexibility of an optical system. Current optical systems with automated alignment capabilities are typically designed to include a dedicated wavefront sensor. Here, we demonstrate a self-aligning method for a reconfigurable system using only focal plane images. We define a two lens optical system with eight degrees of freedom. Images are simulated given misalignment parameters using ZEMAX software. We perform a principal component analysis (PCA) on the simulated dataset to obtain Karhunen-Lo\\`eve (KL) modes, which form the basis set whose weights are the system measurements. A model function which maps the state to the measurement is learned using nonlinear least squares fitting and serves as the measurement function for the nonlinear estimator (Extended and Unscented Kalman filters) used to calculate control inputs to align the system. We present and discuss both simulated and experimental results of the full system in op...

  15. Development of solar-blind AlGaN 128x128 Ultraviolet Focal Plane Arrays

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper reports the development of solar-blind aluminum gallium nitride (AlGaN) 128×128 UV Focal Plane Arrays (FPAs). The back-illuminated hybrid FPA archi- tecture consists of an 128x128 back-illuminated AlGaN PIN detector array that is bump-mounted to a matching 128x128 silicon CMOS readout integrated circuit (ROIC) chip. The 128×128 p-i-n photodiode arrays with cuton and cutoff wave-lengths of 233 and 258 nm, with a sharp reduction in response to UVB (280―320 nm) light. Several examples of solar-blind images are provided. This solar-blind band FPA has much better application prospect.

  16. Direct view zoom scope with single focal plane and adaptable reticle

    Energy Technology Data Exchange (ETDEWEB)

    Bagwell, Brett

    2016-11-15

    A direct view telescopic sight includes objective lens, eyepiece, and prism erector assemblies. The objective lens assembly is mounted to receive light of an image from an object direction and direct the light along an optical path. The eyepiece assembly is mounted to receive the light along the optical path and to emit the light of the image along an eye-ward direction. The prism erector assembly is positioned between the objective lens and eyepiece assemblies and includes first and second prism elements through which the optical path passes. The first and second prism elements invert the image. A reticle element is disposed on or adjacent to a surface of one of the first or second prism elements to combine a reticle on the image. The image is brought into focus at only a single focal plane between the objective lens and eyepiece assemblies at a given time.

  17. Static scene statistical algorithm for nonuniformity correction in focal-plane arrays

    Science.gov (United States)

    Catarius, Adrian M.; Seal, Michael D.

    2015-10-01

    A static scene statistical nonuniformity correction (S3NUC) method was developed based on the higher-order moments of a linear statistical model of a photodetection process. S3NUC relieves the requirement for calibrated targets or a moving scene for NUC by utilizing two data sets of different intensities but requires low scene intensity levels. The first-, second-, and third-order moments of the two data sets are used to estimate the gain and bias values for the detectors in a focal-plane array (FPA). These gain and bias values may then be used to correct the nonuniformities between detectors or to initialize other continuous calibration methods. S3NUC was successfully applied to simulated data as well as measured data at visible wavelengths.

  18. Automated alignment of a reconfigurable optical system using focal-plane sensing and Kalman filtering

    Science.gov (United States)

    Fang, Joyce; Savransky, Dmitry

    2016-08-01

    Automation of alignment tasks can provide improved efficiency and greatly increase the flexibility of an optical system. Current optical systems with automated alignment capabilities are typically designed to include a dedicated wavefront sensor. Here, we demonstrate a self-aligning method for a reconfigurable system using only focal plane images. We define a two lens optical system with eight degrees of freedom. Images are simulated given misalignment parameters using ZEMAX software. We perform a principal component analysis (PCA) on the simulated dataset to obtain Karhunen-Lo\\`eve (KL) modes, which form the basis set whose weights are the system measurements. A model function which maps the state to the measurement is learned using nonlinear least squares fitting and serves as the measurement function for the nonlinear estimator (Extended and Unscented Kalman filters) used to calculate control inputs to align the system. We present and discuss both simulated and experimental results of the full system in operation.

  19. An innovative concept for the AsteroidFinder/SSB focal plane assembly

    Science.gov (United States)

    Schindler, Karsten; Tschentscher, Matthias; Koncz, Alexander; Solbrig, Michael; Michaelis, Harald

    2012-06-01

    This paper gives a summary on the system concept and design of the focal plane assembly of AsteroidFinder/SSB, a small satellite mission which is currently under development at the German Aerospace Center (DLR). An athermal design concept has been developed in accordance to the requirements of the instrument and spacecraft. Key aspects leading to this approach have been a trade-off study of the mechanical telescope interface, the definition of electrical and thermal interfaces and a material selection which minimizes thermally induced stresses. As a novelty, the structure will be manufactured from a machinable AlN-BN composite ceramic. To enable rapid design iterations and development, an integrated modeling approach has been used to conduct a thermo-mechanical analysis of the proposed concept in order to proof its feasibility. The steady-state temperature distribution for various load cases and the resulting stress and strain within the assembly have both been computed using a finite element simulation.

  20. Development of solar-blind AIGaN 128×128 Ultraviolet Focal Plane Arrays

    Institute of Scientific and Technical Information of China (English)

    YUAN YongGang; ZHANG Yan; CHU KaiHui; LI XiangYang; ZHAO DeGang; YANG Hui

    2008-01-01

    This paper reports the development of solar-blind aluminum gallium nitride (AlGaN) 128×128 UV Focal Plane Arrays (FPAs). The back-illuminated hybrid FPA archi-tecture consists of an 128×128 back-illuminated AIGaN PIN detector array that is bump-mounted to a matching 128×128 silicon CMOS readout integrated circuit (ROIC) chip. The 128×128 p-i-n photodiode arrays with cuton and cutoff wave-lengths of 233 and 258 nm, with a sharp reduction in response to UVB (280-320 nm) light. Several examples of solar-blind images are provided. This solar-blind band FPA has much better application prospect.

  1. Focal plane wave-front sensing algorithm for high-contrast imaging

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    High-contrast imaging provided by a coronagraph is critical for the direction imaging of the Earth-like planet orbiting its bright parent star.A major limitation for such direct imaging is the speckle noise that is induced from the wave-front error of an optical system.We derive an algorithm for the wave-front measurement directly from 3 focal plane images.The 3 images are achieved through a deformable mirror to provide specific phases for the optics system.We introduce an extra amplitude modulation on one deformable mirror configuration to create an uncorrelated wave-front,which is a critical procedure for wave-front sensing.The simulation shows that the reconstructed wave-front is consistent with the original wave-front theoretically,which indicates that such an algorithm is a promising technique for the wave-front measurement for the high-contrast imaging.

  2. Development of analog-digital readout integrated circuits for infrared focal plane arrays

    Science.gov (United States)

    Dem'yanenko, M. A.; Kozlov, A. I.; Marchishin, I. V.; Ovsyuk, V. N.

    2016-11-01

    This paper describes the design of readout integrated circuits (ROICs) for hybrid infrared focal plane arrays (IR FPAs). This work contains the estimation of the noise equivalent temperature difference (NETD) of IR FPAs based on frame and row integration of pixel signals in the spectral ranges of 8 to 14 and 3 to 5 μm. This paper also describes the development of ROICs for IR FPAs created with the use of mercury—cadmium—telluride (MCT) photodiodes and quantum well infrared photodetectors (QWIPs). The designed ROICs ensure the use of matrix and linear photodetector chips, including those with increased dark currents, in order to produce IR FPAs with temperature resolution corresponding to the world level of array analogs.

  3. Focal plane wave-front sensin8 algorithm for high-contrast imaging

    Institute of Scientific and Technical Information of China (English)

    DOU JiangPei; REN DeQing; ZHU YongTian; ZHANG Xi

    2009-01-01

    High-contrast imaging provided by a coronagraph is critical for the direction imaging of the Earth-like planet orbiting its bright parent star. A major limitation for such direct imaging is the speckle noise that is induced from the wave-front error of an optical system. We derive an algorithm for the wave-front measurement directly from 3 focal plane images. The 3 images are achieved through a deformable mirror to provide specific phases for the optics system. We introduce an extra amplitude modulation on one deformable mirror configuration to create an uncorrelated wave-front, which is a critical procedure for wave-front sensing. The simulation shows that the reconstructed wave-front is consistent with the original wave-front theoretically, which indicates that such an algorithm is a promising technique for the wave-front measurement for the high-contrast imaging.

  4. An All Silicon Feedhorn-Coupled Focal Plane for Cosmic Microwave Background Polarimetry

    Science.gov (United States)

    Hubmayr, J.; Appel, J. W.; Austermann, J. E.; Beall, J. A.; Becker, D.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Cho, H. M.; hide

    2011-01-01

    Upcoming experiments aim to produce high fidelity polarization maps of the cosmic microwave background. To achieve the required sensitivity, we are developing monolithic, feedhorn-coupled transition edge sensor polarimeter arrays operating at 150 GHz. We describe this focal plane architecture and the current status of this technology, focusing on single-pixel polarimeters being deployed on the Atacama B-mode Search (ABS) and an 84-pixel demonstration feedhorn array backed by four 10-pixel polarimeter arrays. The feedhorn array exhibits symmetric beams, cross-polar response less than -23 dB and excellent uniformity across the array. Monolithic polarimeter arrays, including arrays of silicon feedhorns, will be used in the Atacama Cosmology Telescope Polarimeter (ACTPol) and the South Pole Telescope Polarimeter (SPTpol) and have been proposed for upcoming balloon-borne instruments.

  5. Compensation of focal plane image motion perturbations with optical correlator in feedback loop

    Science.gov (United States)

    Janschek, Klaus; Tchernykh, Valerij; Dyblenko, Serguei; Flandin, Gregory; Harnisch, Bernd

    2004-11-01

    The paper presents a concept of a smart pushbroom imaging system with compensation of attitude instability effects. The compensation is performed by active opto-mechatronic stabilization of the focal plane image motion in a closed loop system with visual feedback on base of an auxiliary matrix image sensor and an onboard optical correlator. In this way the effects of the attitude instability, vibrations and micro shocks can be neutralized, the image quality improved and the requirements to satellite attitude stability reduced. To prove the feasibility and to estimate the effectiveness of the image motion stabilization, a performance model of the smart imaging system has been developed and a simulation experiment has been carried out. The description of the performance model and the results of the simulation experiment are also given.

  6. Mercury-Cadmium-Telluride Focal Plane Array Performance Under Non-Standard Operating Conditions

    Science.gov (United States)

    Richardson, Brandon S.; Eastwood, Michael L.; Bruce, Carl F.; Green, Robert O.; Coles, J. B.

    2011-01-01

    This paper highlights a new technique that allows the Teledyne Scientific & Imaging LLC TCM6604A Mercury-Cadmium-Telluride (MCT) Focal Plane Array (FPA) to operate at room temperature. The Teledyne MCT FPA has been a standard in Imaging Spectroscopy since its creation in the 1980's. This FPA has been used in applications ranging from space instruments such as CRISM, M3 and ARTEMIS to airborne instruments such as MaRS and the Next Generation AVIRIS Instruments1. Precise focal plane alignment is always a challenge for such instruments. The current FPA alignment process results in multiple cold cycles requiring week-long durations, thereby increasing the risk and cost of a project. These alignment cycles are necessary because optimal alignment is approached incrementally and can only be measured with the FPA and Optics at standard operating conditions, requiring a cold instrument. Instruments using this FPA are normally cooled to temperatures below 150K for the MCT FPA to properly function. When the FPA is run at higher temperatures the dark current increases saturating the output. This paper covers the prospect of warm MCT FPA operation from a theoretical and experimental perspective. We discuss the empirical models and physical laws that govern MCT material properties and predict the optimal settings that will result in the best MCT PA performance at 300K. Theoretical results are then calculated for the proposed settings. We finally present the images and data obtained using the actual system with the warm MCT FPA settings. The paper concludes by emphasizing the strong positive correlation between the measured values and the theoretical results.

  7. Non-local means-based nonuniformity correction for infrared focal-plane array detectors

    Science.gov (United States)

    Yu, Hui; Zhang, Zhi-jie; Chen, Fu-sheng; Wang, Chen-sheng

    2014-11-01

    The infrared imaging systems are normally based on the infrared focal-plane array (IRFPA) which can be considered as an array of independent detectors aligned at the focal plane of the imaging system. Unfortunately, every detector on the IRFPA may have a different response to the same input infrared signal which is known as the nonuniformity problem. Then we can observe the fixed pattern noise (FPN) from the resulting images. Standard nonuniformity correction (NUC) methods need to be recalibrated after a short period of time due the temporal drift of the FPN. Scene-based nonuniformity correction (NUC) techniques eliminate the need for calibration by correction coefficients based on the scene being viewed. However, in the scene-based NUC method the problem of ghosting artifacts widely seriously decreases the image quality, which can degrade the performance of many applications such as target detection and track. This paper proposed an improved scene-based method based on the retina-like neural network approach. The method incorporates the use of non-local means (NLM) method into the estimation of the gain and the offset of each detector. This method can not only estimates the accurate correction coefficient but also restrict the ghosting artifacts efficiently. The proposed method relies on the use of NLM method which is a very successful image denoising method. And then the NLM used here can preserve the image edges efficiently and obtain a reliable spatial estimation. We tested the proposed NUC method by applying it to an IR sequence of frames. The performance of the proposed method was compared the other well-established adaptive NUC techniques.

  8. Mercury-Cadmium-Telluride Focal Plane Array Performance Under Non-Standard Operating Conditions

    Science.gov (United States)

    Richardson, Brandon S.; Eastwood, Michael L.; Bruce, Carl F.; Green, Robert O.; Coles, J. B.

    2011-01-01

    This paper highlights a new technique that allows the Teledyne Scientific & Imaging LLC TCM6604A Mercury-Cadmium-Telluride (MCT) Focal Plane Array (FPA) to operate at room temperature. The Teledyne MCT FPA has been a standard in Imaging Spectroscopy since its creation in the 1980's. This FPA has been used in applications ranging from space instruments such as CRISM, M3 and ARTEMIS to airborne instruments such as MaRS and the Next Generation AVIRIS Instruments1. Precise focal plane alignment is always a challenge for such instruments. The current FPA alignment process results in multiple cold cycles requiring week-long durations, thereby increasing the risk and cost of a project. These alignment cycles are necessary because optimal alignment is approached incrementally and can only be measured with the FPA and Optics at standard operating conditions, requiring a cold instrument. Instruments using this FPA are normally cooled to temperatures below 150K for the MCT FPA to properly function. When the FPA is run at higher temperatures the dark current increases saturating the output. This paper covers the prospect of warm MCT FPA operation from a theoretical and experimental perspective. We discuss the empirical models and physical laws that govern MCT material properties and predict the optimal settings that will result in the best MCT PA performance at 300K. Theoretical results are then calculated for the proposed settings. We finally present the images and data obtained using the actual system with the warm MCT FPA settings. The paper concludes by emphasizing the strong positive correlation between the measured values and the theoretical results.

  9. Focal plane actuation by hexapod for the development of a high-resolution suborbital telescope

    Science.gov (United States)

    Miller, Alexander D.; Scowen, Paul A.; Veach, Todd J.

    2016-07-01

    We present a prototype hexapod image stabilization system as the key instrument for a proposed suborbital balloon mission. The unique design thermally isolates an off-the-shelf non-cryogenic hexapod from a liquid nitrogen cooled focal plane, enabling its use in a cryogenic environment. Balloon gondolas currently achieve 1-2 arcsecond pointing error, but cannot correct for unavoidable jitter movements ( 20 micron amplitude at 20 Hz at the worst) caused by wind rushing over balloon surfaces, thermal variations, and vibrations from cryocoolers, and reaction wheels. The jitter causes image blur during exposures and limits the resolution of the system. Removal of this final jitter term decreases pointing error by an order of magnitude and allows for true diffraction-limited observation. Tip-tilt pointing systems have been used for these purposes in the past, but require additional optics and introduce multiple reflections. The hexapod system, rather, is compact and can be plugged into the focal point of nearly any configuration. For a 0.8m telescope the improvement in resolution by this system would provide 0.1" angular resolution at 300nm, which is comparable to Hubble for a fraction of the cost. On an actual balloon, the hexapod system would actuate the focal plane to counteract the jitter using position information supplied by guidestar cameras. However, in the lab, we instead simulate guide camera tracking, using a 1024 × 1024 e2v science-grade CCD to take long exposures of a target attached to an XY stage driven with the balloon jitter signal recorded during the STO mission. Further confirmation of the positional accuracy and agility of the hexapod is achieved using a laser and fast-sampling position-sensitive diode. High-resolution time domain multispectral imaging of the gas giants, especially in the UV range, is of particular interest to the planetary community, and a suborbital telescope with the hexapod stabilization in place would provide a wealth of new

  10. Charge integration successive approximation analog-to-digital converter for focal plane applications using a single amplifier

    Science.gov (United States)

    Zhou, Zhimin (Inventor); Pain, Bedabrata (Inventor)

    1999-01-01

    An analog-to-digital converter for on-chip focal-plane image sensor applications. The analog-to-digital converter utilizes a single charge integrating amplifier in a charge balancing architecture to implement successive approximation analog-to-digital conversion. This design requires minimal chip area and has high speed and low power dissipation for operation in the 2-10 bit range. The invention is particularly well suited to CMOS on-chip applications requiring many analog-to-digital converters, such as column-parallel focal-plane architectures.

  11. Tests of the Monte Carlo simulation of the photon-tagger focal-plane electronics at the MAX IV Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Preston, M.F. [Lund University, SE-221 00 Lund (Sweden); Myers, L.S. [Duke University, Durham, NC 27708 (United States); Annand, J.R.M. [University of Glasgow, Glasgow G12 8QQ, Scotland (United Kingdom); Fissum, K.G., E-mail: kevin.fissum@nuclear.lu.se [Lund University, SE-221 00 Lund (Sweden); Hansen, K.; Isaksson, L. [MAX IV Laboratory, Lund University, SE-221 00 Lund (Sweden); Jebali, R. [Arktis Radiation Detectors Limited, 8045 Zürich (Switzerland); Lundin, M. [MAX IV Laboratory, Lund University, SE-221 00 Lund (Sweden)

    2014-04-21

    Rate-dependent effects in the electronics used to instrument the tagger focal plane at the MAX IV Laboratory were recently investigated using the novel approach of Monte Carlo simulation to allow for normalization of high-rate experimental data acquired with single-hit time-to-digital converters (TDCs). The instrumentation of the tagger focal plane has now been expanded to include multi-hit TDCs. The agreement between results obtained from data taken using single-hit and multi-hit TDCs demonstrate a thorough understanding of the behavior of the detector system.

  12. Finding the Dark Hole with the Lights On: A New Approach to Focal Plane Wavefront Sensing

    CERN Document Server

    Frazin, Richard A

    2016-01-01

    In direct imaging of exoplanets from space, achieving the required dynamic range (i.e., planet-to-star contrast in brightness) currently relies on coronagraphic technology combined with active control of one or more deformable mirrors (DMs) to create a dark region in the image plane, sometimes called a "dark hole." While many algorithms have been proposed for this purpose, all of them employ focal plane wavefront sensing (FPWS) in order to calculate the optimal DM configuration to create the desired dark hole. All current algorithms are limited by their own success in that, as the dark hole is achieved, the FPWS procedure becomes shot-noise limited due to he low intensity in the dark hole. This article proposes a FPWS procedure that allows determination of the optimal DM configuration without relying on information obtained when the DM is near the optimal configuration. This article gives regression procedures for FPWS that do not assume the DM step size is small, which should allow two important improvements...

  13. Performance enhancement of uncooled infrared focal plane array by integrating metamaterial absorber

    Science.gov (United States)

    Ma, Wei; Wen, Yongzheng; Yu, Xiaomei; Feng, Yun; Zhao, Yuejin

    2015-03-01

    This letter presents an infrared (IR) focal plane array (FPA) with metamaterial absorber (MMA) integrated to enhance its performance. A glass substrate, on which arrays of bimaterial cantilevers are fabricated as the thermal-sensitive pixels by a polyimide surface sacrificial process, is employed to allow the optical readout from the back side of the substrate. Whereas the IR wave radiates onto the FPA from the front side, which consequently avoids the energy loss caused by the silicon substrate compared with the previous works. This structure also facilitates the integration of MMA by introducing a layer of periodic square resonators atop the SiNx structural layer to form a metal/dielectric/metal stack with the gold mirror functioning as the ground plane. A comparative experiment was carried out on the FPAs that use MMA and ordinary SiNx as the absorbers, respectively. The performance improvement was verified by the evaluation of the absorbers as well as the imaging results of both FPAs.

  14. Antennas for Terahertz Applications: Focal Plane Arrays and On-chip Non-contact Measurement Probes

    Science.gov (United States)

    Trichopoulos, Georgios C.

    The terahertz (THz) band provides unique sensing opportunities that enable several important applications such as biomedical imaging, remote non-destructive inspection of packaged goods, and security screening. THz waves can penetrate most materials and can provide unique spectral information in the 0.1--10 THz band with high resolution. In contrast, other imaging modalities, like infrared (IR), suffer from low penetration depths and are thus not attractive for non-destructive evaluation. However, state-of-the-art THz imaging systems typically employ mechanical raster scans using a single detector to acquire two-dimensional images. Such devices tend to be bulky and complicated due to the mechanical parts, and are thus rather expensive to develop and operate. Thus, large-format (e.g. 100x100 pixels) and all-electronics based THz imaging systems are badly needed to alleviate the space, weight and power (SWAP) factors and enable cost effective utilization of THz waves for sensing and high-data-rate communications. In contrast, photonic sensors are very compact because light can couple directly to the photodiode without residing to radiation coupling topologies. However, in the THz band, due to the longer wavelengths and much lower photon energies, highly efficient antennas with optimized input impedance have to be integrated with THz sensors. Here, we implement novel antenna engineering techniques that are optimized to take advantage of recent technological advances in solid-state THz sensing devices. For example, large-format focal plane arrays (FPAs) have been the Achilles' heel of THz imaging systems. Typically, optical components (lenses, mirrors) are employed in order to improve the optical performance of FPAs, however, antenna sensors suffer from degraded performance when they are far from the optical axis, thus minimizing the number of useful FPA elements. By modifying the radiation pattern of FPA antennas we manage to alleviate the off-axis aberration

  15. Performance of MWIR and SWIR HgCdTe-based focal plane arrays at high operating temperatures

    Science.gov (United States)

    Melkonian, Leon; Bangs, James; Elizondo, Lee; Ramey, Ron; Guerrero, Ernesto

    2010-04-01

    Raytheon Vision Systems (RVS) is producing large format, high definition HgCdTe-based MWIR and SWIR focal plane arrays (FPAs) with pitches of 15 μm and smaller for various applications. Infrared sensors fabricated from HgCdTe have several advantages when compared to those fabricated from other materials -- such as a highly tunable bandgap, high quantum efficiencies, and R0A approaching theoretical limits. It is desirable to operate infrared sensors at elevated operating temperatures in order to increase the cooler life and reduce the required system power. However, the sensitivity of many infrared sensors, including those made from HgCdTe, declines significantly above a certain temperature due to the noise resulting from increasing detector dark current. In this paper we provide performance data on a MWIR and a SWIR focal plane array operating at temperatures up to 160K and 170K, respectively. The FPAs used in the study were grown by molecular beam epitaxy (MBE) on silicon substrates, processed into a 1536x1024 format with a 15 μm pixel pitch, and hybridized to a silicon readout integrated circuit (ROIC) via indium bumps to form a sensor chip assembly (SCA). This data shows that the noise equivalent delta temperature (NEDT) is background limited at f/3.4 in the SWIR SCA (cutoff wavelength of 3.7 μm at 130K) up to 140K and in the MWIR SCA (cutoff wavelength of 4.8 μm at 115K) up to 115K.

  16. HEB heterodyne focal plane arrays: a terahertz technology for high sensitivity near-range security imaging systems

    Science.gov (United States)

    Gerecht, Eyal; Gu, Dazhen; Yngvesson, Sigfrid; Rodriguez-Morales, Fernando; Zannoni, R.; Nicholson, John

    2005-05-01

    We have achieved the first demonstration of a low-noise heterodyne array operating at a frequency above 1 THz (1.6 THz). The prototype array has three elements, consisting of NbN hot electron bolometer (HEB) detectors on silicon substrates. We use a quasi-optical design to couple the signal and local oscillator (LO) power to the detector. We also demonstrate, for the first time, how the HEB detectors can be intimately integrated in the same block with monolithic microwave integrated circuit (MMIC) IF amplifiers. Such focal plane arrays can be increased in size to a few hundred elements using the next generation fabrication architecture for compact and easy assembly. Future HEB-based focal plane arrays will make low-noise heterodyne imaging systems with high angular resolution possible from 500 GHz to several terahertz. Large low-noise HEB arrays are well suited for real-time video imaging at any frequency over the entire terahertz spectrum. This is made possible by virtue of the extremely low local oscillator power requirements of the HEB detectors (a few hundred nanowatts to a microwatt per pixel). The operating temperature is 4 to 6 K, which can be provided by a compact and mobile cryocooler system, developed as a spin-off from the space program. The terahertz HEB imager consists of a computer-controlled optical system mounted on an elevation and azimuth scanning translator which provides a two-dimensional image of the target. We present preliminary measured data at the symposium for a terahertz security system of this type.

  17. CdTe Focal Plane Detector for Hard X-Ray Focusing Optics

    Science.gov (United States)

    Seller, Paul; Wilson, Matthew D.; Veale, Matthew C.; Schneider, Andreas; Gaskin, Jessica; Wilson-Hodge, Colleen; Christe, Steven; Shih, Albert Y.; Inglis, Andrew; Panessa, Marco

    2015-01-01

    The demand for higher resolution x-ray optics (a few arcseconds or better) in the areas of astrophysics and solar science has, in turn, driven the development of complementary detectors. These detectors should have fine pixels, necessary to appropriately oversample the optics at a given focal length, and an energy response also matched to that of the optics. Rutherford Appleton Laboratory have developed a 3-side buttable, 20 millimeter x 20 millimeter CdTe-based detector with 250 micrometer square pixels (80 x 80 pixels) which achieves 1 kiloelectronvolt FWHM (Full-Width Half-Maximum) @ 60 kiloelectronvolts and gives full spectroscopy between 5 kiloelectronvolts and 200 kiloelectronvolts. An added advantage of these detectors is that they have a full-frame readout rate of 10 kilohertz. Working with NASA Goddard Space Flight Center and Marshall Space Flight Center, 4 of these 1 millimeter-thick CdTe detectors are tiled into a 2 x 2 array for use at the focal plane of a balloon-borne hard-x-ray telescope, and a similar configuration could be suitable for astrophysics and solar space-based missions. This effort encompasses the fabrication and testing of flight-suitable front-end electronics and calibration of the assembled detector arrays. We explain the operation of the pixelated ASIC readout and measurements, front-end electronics development, preliminary X-ray imaging and spectral performance, and plans for full calibration of the detector assemblies. Work done in conjunction with the NASA Centers is funded through the NASA Science Mission Directorate Astrophysics Research and Analysis Program.

  18. Hierarchical Phased Array Antenna Focal Plane for Cosmic Microwave Background Polarization and Sub-mm Observations

    Science.gov (United States)

    Lee, Adrian

    We propose to develop planar-antenna-coupled superconducting bolometer arrays for observations at sub-millimeter to millimeter wavelengths. Our pixel architecture features a dual-polarization, log-periodic antenna with a 5:1 bandwidth ratio, followed by a filter bank that divides the total bandwidth into several broad photometric bands. We propose to develop an hierarchical phased array of our basic pixel type that gives optimal mapping speed (sensitivity) over a much broader range of frequencies. The advantage of this combination of an intrinsically broadband pixel with hierarchical phase arraying include a combination of greatly reduced focal-plane mass, higher array sensitivity, and a larger number of spectral bands compared to focal-plane designs using conventional single-color pixels. These advantages have the potential to greatly reduce cost and/or increase performance of NASA missions in the sub-millimeter to millimeter bands. For CMB polarization, a wide frequency range of about 30 to 400 GHz is required to subtract galactic foregrounds. As an example, the multichroic architecture we propose could reduce the focal plane mass of the EPIC-IM CMB polarization mission study concept by a factor of 4, with great savings in required cryocooler performance and therefore cost. We have demonstrated the lens-coupled antenna concept in the POLARBEAR groundbased CMB polarization experiment which is now operating in Chile. That experiment uses a single-band planar antenna that gives excellent beam properties and optical efficiency. POLARBEAR recently succeeded in detecting gravitational lensing B-modes in the CMB polarization. In the laboratory, we have measured two octaves of total bandwidth in the log-periodic sinuous antenna. We have built filter banks of 2, 3, and 7 bands with 4, 6, and 14 bolometers per pixel for two linear polarizations. Pixels of this type are slated to be deployed on the ground in POLARBEAR and SPT-3G and proposed to be used on a balloon by EBEX

  19. Examination of cotton fibers and common contaminants using an infrared microscope and a focal-plane array detector

    Science.gov (United States)

    The chemical imaging of cotton fibers and common contaminants in fibers is presented. Chemical imaging was performed with an infrared microscope equipped with a Focal-Plane Array (FPA) detector. Infrared spectroscopy can provide us with information on the structure and quality of cotton fibers. In a...

  20. Leaky Lens Based UWB Focal Plane Arrays for Sub-mm Wave Imaging Based on Kinetic Inductance Detectors

    NARCIS (Netherlands)

    Neto, A.; Iacono, A.; Gerini, G.; Baselmans, J.J.A.; Yates, S.J.C.; Baryshev, A.; Hoovers, H.F.C.

    2009-01-01

    This work highlights some of the results of a cooperation between TNO and SRON (Space Research Organization Netherlands) which is now going on with renewed efforts since almost two years. A novel strategy for broad band focal plane array design is proposed. Its purpose is to couple the radiation fro

  1. A Statistical Framework for Utilization of Simultaneous Pupil Plane and Focal Plane Telemetry for Exoplanet Imaging, Part I: Accounting for Polarization Aberration in Multiple Planes

    CERN Document Server

    Frazin, Richard A

    2016-01-01

    A new generation of telescopes with mirror diameters of 20 m or more, called extremely large telescopes (ELTs) has the potential to provide unprecedented imaging and spectroscopy of exo-planetary systems, if the difficulties in achieving the extremely high dynamic range required to differentiate the planetary signal from the star can be overcome to a sufficient degree. Fully utilizing the potential of ELTs for exoplanet imaging will likely require simultaneous and self-consistent determination both the planetary image and the unknown aberrations in multiple planes of the optical system, using statistical inference based on the wavefront sensor and science camera data streams. This paper is the first in a series on this subject, in which a formalism is established for the exoplanet imaging problem in a polarizing optical system that has optical aberrations in multiple planes. Every effort has been made to be rigorous and complete, so that that validity of approximations to be made later can be assessed. It is ...

  2. Adaptive scene-based nonuniformity correction method for infrared-focal plane arrays

    Science.gov (United States)

    Torres, Sergio N.; Vera, Esteban M.; Reeves, Rodrigo A.; Sobarzo, Sergio K.

    2003-08-01

    The non-uniform response in infrared focal plane array (IRFPA) detectors produces corrupted images with a fixed-pattern noise. In this paper we present an enhanced adaptive scene-based non-uniformity correction (NUC) technique. The method simultaneously estimates detector's parameters and performs the non-uniformity compensation using a neural network approach. In addition, the proposed method doesn't make any assumption on the kind or amount of non-uniformity presented on the raw data. The strength and robustness of the proposed method relies in avoiding the presence of ghosting artifacts through the use of optimization techniques in the parameter estimation learning process, such as: momentum, regularization, and adaptive learning rate. The proposed method has been tested with video sequences of simulated and real infrared data taken with an InSb IRFPA, reaching high correction levels, reducing the fixed pattern noise, decreasing the ghosting, and obtaining an effective frame by frame adaptive estimation of each detector's gain and offset.

  3. Required composition uniformity of Hg1-xCdxTe substrate for focal plane arrays

    Science.gov (United States)

    Gopal, Vishnu

    1996-10-01

    This paper presents a comparison of theoretically predicted spatial NETD and mean temporal NETD as a function of the composition uniformity of Hg(subscript 1-x)Cd(subscript x)Te substrate used in the fabrication of IR detector arrays. The prediction of the spatial NETD is based on the residual spatial noise left behind in the FPA after implementing a linear two point nonuniformity compensation algorithm. The effect of using an optical filter on the spatial NETD is also included to show that the specifications on the composition uniformity of the Hg(subscript 1-x)Cd(subscript x)Te substrate can be partially relaxed by using an optical filter whose cut-off wavelength is less than the cutoff wavelength of the photodiodes of mean response. The composition uniformity leading to temporal noise rather than the spatial noise limited performances are suggested to be indicating the required composition uniformity of Hg(subscript 1-x)Cd(subscript x)Te substrate for focal plane arrays (FPA). The results are presented for both MWIR and LWIR HgCdTe hybrid FPAs.

  4. Research progress on a focal plane array ladar system using chirped amplitude modulation

    Science.gov (United States)

    Stann, Barry L.; Abou-Auf, Ahmed; Aliberti, Keith; Dammann, John; Giza, Mark; Dang, Gerard; Ovrebo, Greg; Redman, Brian; Ruff, William; Simon, Deborah

    2003-08-01

    The Army Research Laboratory is researching a focal plane array (FPA) ladar architecture that is applicable for smart munitions, reconnaissance, face recognition, robotic navigation, etc.. Here we report on progress and test results attained over the past year related to the construction of a 32x32 pixel FPA ladar laboratory breadboard. The near-term objective of this effort is to evaluate and demonstrate an FPA ladar using chirped amplitude modulation; knowledge gained will then be used to build a field testable version with a larger array format. The ladar architecture achieves ranging based on a frequency modulation/continuous wave technique implemented by directly amplitude modulating a near-IR diode laser transmitter with a radio frequency (rf) subcarrier that is linearly frequency modulated (chirped amplitude modulation). The diode's output is collected and projected to form an illumination field in the downrange image area. The returned signal is focused onto an array of optoelectronic mixing, metal-semiconductor-metal detectors where it is detected and mixed with a delayed replica of the laser modulation signal that modulates the responsivity of each detector. The output of each detector is an intermediate frequency (IF) signal resulting from the mixing process whose frequency is proportional to the target range. This IF signal is continuously sampled over a period of the rf modulation. Following this, a signal processor calculates the discrete fast Fourier transform over the IF waveform in each pixel to establish the ranges and amplitudes of all scatterers.

  5. High-resolution focal plane array IR detection modules and digital signal processing technologies at AIM

    Science.gov (United States)

    Cabanski, Wolfgang A.; Breiter, Rainer; Koch, R.; Mauk, Karl-Heinz; Rode, Werner; Ziegler, Johann; Eberhardt, Kurt; Oelmaier, Reinhard; Schneider, Harald; Walther, Martin

    2000-07-01

    Full video format focal plane array (FPA) modules with up to 640 X 512 pixels have been developed for high resolution imaging applications in either mercury cadmium telluride (MCT) mid wave (MWIR) infrared (IR) or platinum silicide (PtSi) and quantum well infrared photodetector (QWIP) technology as low cost alternatives to MCT for high performance IR imaging in the MWIR or long wave spectral band (LWIR). For the QWIP's, a new photovoltaic technology was introduced for improved NETD performance and higher dynamic range. MCT units provide fast frame rates > 100 Hz together with state of the art thermal resolution NETD rates of 30 - 60 Hz and provide thermal resolutions of NETD exchangeability of the units. New modular image processing hardware platforms and software for image visualization and nonuniformity correction including scene based self learning algorithms had to be developed to accomplish for the high data rates of up to 18 M pixels/s with 14-bit deep data, allowing to take into account nonlinear effects to access the full NETD by accurate reduction of residual fixed pattern noise. The main features of these modules are summarized together with measured performance data for long range detection systems with moderately fast to slow F-numbers like F/2.0 - F/3.5. An outlook shows most recent activities at AIM, heading for multicolor and faster frame rate detector modules based on MCT devices.

  6. Design and performance of the ULTRA 320x240 uncooled focal plane array and sensor

    Science.gov (United States)

    Herring, Robert J.; Howard, Philip E.

    1996-06-01

    The ULTRA (Uncooled, Low cost, Technology Reinvestment Alliance) Consortium, consisting of the Honeywell Technology Center of Honeywell Incorporated, the Autonetics Missile Systems Division of Rockwell International Corporation, Inframetrics Incorporated, and the New Jersey Institute of Technology, has been formally working together over the past year in an effort to develop, manufacture and sell industrial and military sensors and components incorporating silicon microbolometer uncooled focal plane array (UFPA) technology. Towards that end, Rockwell has been actively engaged in developing the UFPA component, with assistance from Honeywell, with the intention of being a merchant supplier of the UFPA. Inframetrics has been developing subsystems required to construct and characterize a prototype sensor, and NJIT is designing a Multi-Wavelength Imaging Pyrometry system around the performance of the uncooled prototype sensor. TRP Office funding administered by ARPA has been key to the significant advances made over the course of the year in this program. This paper will describe both the UFPA component specification and the prototype sensor. It will give a architectural overview of the detector array, with the anticipated performance characteristics. Multiplexer design and simulation, and array processing, will be addressed. A description of the array packaging, interface requirements, and unique design considerations will be provided. Anticipated and actual component performance will be explained and contrasted. The background of the sensor development will be presented. An overview of the camera architecture will be given, with some discussion of trade-offs in subsystem design of the sensor. Specific emphasis is placed on the radiometric evaluation of the sensor.

  7. An improved retina-like nonuniformity correction for infrared focal-plane array

    Science.gov (United States)

    Yu, Hui; Zhang, Zhi-jie; Wang, Chen-sheng

    2015-11-01

    The non-uniform response in infrared focal plane array (IRFPA) detectors produces corrupted images with nonuniformity noise. This paper mainly proposes an improved adaptive nonuniformity correction (NUC) method based on the retina-like neural network approach. The main purpose of NUC method is to obtain reliable estimations of gain and offset parameters. In this paper the two correction parameters are updated with two different learning rates respectively for the purpose of updating these two parameters synchronously. And then more accurate estimations of the two correction parameters can be obtained. Again, in order to reduce the ghost artifacts normally introduced by the strong edge effectively, the proposed algorithm employs the non-local means (NLM) method to estimate the desired target value of each detector. The proposed NUC method has been tested by applying it to the IR sequence of frames with simulated nonuniformity noise and real nonuniformity noise, respectively. The performance comparisons are implemented with the well-established scene-based NUC techniques. And the experimental results show the efficiency of the proposed method.

  8. An Improved Scene-based Nonuniformity Correction Algorithm for Infrared Focal Plane Arrays Using Neural Networks

    Institute of Scientific and Technical Information of China (English)

    SUI Jing; JIN Wei-qi; DONG Li-quan; WANG Xia; GUO Hong

    2006-01-01

    The improved scene-based adaptive nonuniformity correction (NUC) algorithms using a neural network (NNT) approach for infrared image sequences are presented and analyzed. The retina-like neural networks using steepest descent model was the first proposed infrared focal plane arrays (IRFPA) nonuniformity compensation method, which can perform parameter estimation of the sensors over time on a frame by frame basis. To increase the strength and the robustness of the NNT algorithm and to avoid the presence of ghosting artifacts, some optimization techniques, including momentum term,regularization factor and adaptive learning rate, were executed in the parameter learning process. In this paper, the local median filtering result of Xij ( n ) is proposed as an alternative value of desired network output of neuron Xij ( n ), denoted as Tij ( n ), which is the local spatial average of Xij ( n ) in traditional NNT methods. Noticeably, the NUC algorithm is inter-frame adaptive in nature and does not rely on any statistical assumptions on the scene data in the image sequence.Applications of this algorithm to the simulated video sequences and real infrared data taken with PV320 show that the correction results of image sequence are better than that of using original NNT approach, especially for the short-time image sequences (several hundred frames) subjected to the dense impulse noises with a number of dead or saturated pixels.

  9. Test stand for non-uniformity correction of microbolometer focal plane arrays used in thermal cameras

    Science.gov (United States)

    Krupiński, Michał; Bareła, Jaroslaw; Firmanty, Krzysztof; Kastek, Mariusz

    2013-10-01

    Uneven response of particular detectors (pixels) to the same incident power of infrared radiation is an inherent feature of microbolometer focal plane arrays. As a result an image degradation occurs, known as Fixed Pattern Noise (FPN), which distorts the thermal representation of an observed scene and impairs the parameters of a thermal camera. In order to compensate such non-uniformity, several NUC correction methods are applied in digital data processing modules implemented in thermal cameras. Coefficients required to perform the non-uniformity correction procedure (NUC coefficients) are determined by calibrating the camera against uniform radiation sources (blackbodies). Non-uniformity correction is performed in a digital processing unit in order to remove FPN pattern in the registered thermal images. Relevant correction coefficients are calculated on the basis of recorded detector responses to several values of radiant flux emitted from reference IR radiation sources (blackbodies). The measurement of correction coefficients requires specialized setup, in which uniform, extended radiation sources with high temperature stability are one of key elements. Measurement stand for NUC correction developed in Institute of Optoelectronics, MUT, comprises two integrated extended blackbodies with the following specifications: area 200×200 mm, stabilized absolute temperature range +15 °C÷100 °C, and uniformity of temperature distribution across entire surface +/-0.014 °C. Test stand, method used for the measurement of NUC coefficients and the results obtained during the measurements conducted on a prototype thermal camera will be presented in the paper.

  10. Locally adaptive regression filter-based infrared focal plane array non-uniformity correction

    Science.gov (United States)

    Li, Jia; Qin, Hanlin; Yan, Xiang; Huang, He; Zhao, Yingjuan; Zhou, Huixin

    2015-10-01

    Due to the limitations of the manufacturing technology, the response rates to the same infrared radiation intensity in each infrared detector unit are not identical. As a result, the non-uniformity of infrared focal plane array, also known as fixed pattern noise (FPN), is generated. To solve this problem, correcting the non-uniformity in infrared image is a promising approach, and many non-uniformity correction (NUC) methods have been proposed. However, they have some defects such as slow convergence, ghosting and scene degradation. To overcome these defects, a novel non-uniformity correction method based on locally adaptive regression filter is proposed. First, locally adaptive regression method is used to separate the infrared image into base layer containing main scene information and the detail layer containing detailed scene with FPN. Then, the detail layer sequence is filtered by non-linear temporal filter to obtain the non-uniformity. Finally, the high quality infrared image is obtained by subtracting non-uniformity component from original image. The experimental results show that the proposed method can significantly eliminate the ghosting and the scene degradation. The results of correction are superior to the THPF-NUC and NN-NUC in the aspects of subjective visual and objective evaluation index.

  11. Empirical frequency domain model for fixed-pattern noise in infrared focal plane arrays

    Science.gov (United States)

    Pérez, Francisco; Pezoa, Jorge E.; Figueroa, Miguel; Torres, Sergio N.

    2014-11-01

    In this paper, a new empirical model for the spatial structure of the fixed-pattern noise (FPN) observed in infrared (IR) focal-plane arrays (FPA) is presented. The model was conceived after analyzing, in the spatial frequency domain, FPN calibration data from different IR cameras and technologies. The analysis showed that the spatial patterns of the FPN are retained in the phase spectrum, while the noise intensity is determined by the magnitude spectrum. Thus, unlike traditional representations, the proposed model abstracts the FPN structure using one matrix for its magnitude spectrum and another matrix for its phase spectrum. Three applications of the model are addressed here. First, an algorithm is provided for generating random samples of the FPN with the same spatial pattern of the actual FPN. Second, the model is used to assess the performance of non-uniformity correction (NUC) algorithms in the presence of spatially correlated and uncorrelated FPN. Third, the model is used to improve the NUC capability of a method that requires, as a reference, a proper FPN sample.

  12. High Dynamic Range adaptive ΔΣ-based Focal Plane Array architecture

    KAUST Repository

    Yao, Shun

    2012-10-16

    In this paper, an Adaptive Delta-Sigma based architecture for High Dynamic Range (HDR) Focal Plane Arrays is presented. The noise shaping effect of the Delta-Sigma modulation in the low end, and the distortion noise induced in the high end of Photo-diode current were analyzed in detail. The proposed architecture can extend the DR for about 20N log2 dB at the high end of Photo-diode current with an N bit Up-Down counter. At the low end, it can compensate for the larger readout noise by employing Extended Counting. The Adaptive Delta-Sigma architecture employing a 4-bit Up-Down counter achieved about 160dB in the DR, with a Peak SNR (PSNR) of 80dB at the high end. Compared to the other HDR architectures, the Adaptive Delta-Sigma based architecture provides the widest DR with the best SNR performance in the extended range.

  13. Two-color HgCdTe infrared staring focal plane arrays

    Science.gov (United States)

    Smith, Edward P.; Pham, Le T.; Venzor, Gregory M.; Norton, Elyse; Newton, Michael; Goetz, Paul; Randall, Valerie; Pierce, Gregory; Patten, Elizabeth A.; Coussa, Raymond A.; Kosai, Ken; Radford, William A.; Edwards, John; Johnson, Scott M.; Baur, Stefan T.; Roth, John A.; Nosho, Brett; Jensen, John E.; Longshore, Randolph E.

    2003-12-01

    Raytheon Vision Systems (RVS) in collaboration with HRL Laboratories is contributing to the maturation and manufacturing readiness of third-generation two-color HgCdTe infrared staring focal plane arrays (FPAs). This paper will highlight data from the routine growth and fabrication of 256x256 30μm unit-cell staring FPAs that provide dual-color detection in the mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) spectral regions. FPAs configured for MWIR/MWIR, MWIR/LWIR and LWIR/LWIR detection are used for target identification, signature recognition and clutter rejection in a wide variety of space and ground-based applications. Optimized triple-layer-heterojunction (TLHJ) device designs and molecular beam epitaxy (MBE) growth using in-situ controls has contributed to individual bands in all two-color FPA configurations exhibiting high operability (>99%) and both performance and FPA functionality comparable to state-of-the-art single-color technology. The measured spectral cross talk from out-of-band radiation for either band is also typically less than 10%. An FPA architecture based on a single mesa, single indium bump, and sequential mode operation leverages current single-color processes in production while also providing compatibility with existing second-generation technologies.

  14. Development of miniature Stirling cryocooler technology for Infrared Focal Plane array

    Directory of Open Access Journals (Sweden)

    Manmohan Singh

    2013-12-01

    Full Text Available A reliable miniature cryocooler is one of the basic and foremost requirements for successful operation of high performance cooled infrared focal plane array (IRFPA used for defence applications. Technological complexity and requirement of long duration fail-safe operation of the cryocooler demands robust design, fabrication and assembly with tolerances and, perfection of an array of sub-technologies. The paper presents the progress of the development activities in Stirling cryocooler technology at SSPL, which evolved through essential milestones like the development of single and dual piston linear motor driven split coolers to the state-of-the-art integral Brushless DC (BLDC motor crank-driven type highly miniaturized coolers of capacities ranging from 0.25 to 0.5W at 80K. The theoretical investigations in the design of Stirling cycle cryocooler have been reported and the issues related to the design aspects are discussed in sufficient details. Experimental results of cryocooler performance tests are also presented. The paper also focuses on regenerator design optimization. The results of optimizations have been shown at the end considering a sample data.Defence Science Journal, 2013, 63(6, pp.571-580, DOI:http://dx.doi.org/10.14429/dsj.63.5756

  15. GRIFEX Payload Data System Architecture for On-Orbit Focal Plane Array Evaluation

    Science.gov (United States)

    Bekker, D. L.; Bryk, M.; DeLucca, J.; Franklin, B.; Hancock, B.; Klesh, A. T.; Meehan, C.; Meshkaty, N.; Nichols, J.; Pingree, P.; Rider, D. M.; Werne, T.; Wu, J.

    2012-12-01

    The GEO-CAPE ROIC In-Flight Performance Experiment (GRIFEX) is 3U CubeSat mission with the goal of on-orbit verification of a high performance focal plane array (FPA). The FPA is a custom silicon PIN diode array hybridized to the JPL-developed GEO-CAPE readout integrated circuit (ROIC). The FPA is 128 x 128 pixels, with a frame rate of up to 16 kHz, and 14 bits-per-pixel dynamic range. The FPA is designed to meet the measurement requirements of the PanFTS instrument, currently in development for the Earth Science Decadal Survey Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission. The GRIFEX FPA will operate at 8 kHz frame rate, producing a 1.84 Gbps data stream. This data will be buffered in the GRIFEX data system and will be telemetered to a ground station at the University of Michigan in short bursts when the GRIFEX CubeSat is in view of the station. The work presented here highlights the development of the GRIFEX payload data system, with emphasis on the system architecture, data storage strategy, and payload operations. Considerations for low power design and radiation robustness are also discussed. Initial images and a characterization of the FPA performance is presented. The GRIFEX mission is a joint effort between JPL (payload) and the University of Michigan (CubeSat). The launch is scheduled for 2014.

  16. Status of the JWST/MIRI Focal Plane System and Cooler

    Science.gov (United States)

    Ressler, Michael E.; Goodson, G. B.; Khorrami, M. A.; Larson, M. E.; Mahoney, J. C.; Sukhatme, K. G.

    2009-01-01

    The Mid-Infrared Instrument (MIRI) is a multipurpose imager, coronagraph, and spectrometer for the James Webb Space Telescope. It provides wavelength coverage from 5 through 28 microns and is an integral contributor to all four of JWST's primary science themes. MIRI is being developed as a partnership between NASA and ESA, with JPL providing the Focal Plane System (FPS, consisting of the detectors, control electronics, and flight software) and the cooler, and a consortium of European astronomical institutes providing the optical bench and structure. The flight FPS is being prepared for delivery to the European Consortium for its integration into the optical bench, while the cooler is nearing its Critical Design Review. We describe the capabilities of the FPS and cooler, present test results and the predicted sensitivity performance of the FPS, and update the current status of each these systems. The research described in this poster was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  17. A Frequency Selective Surface based focal plane receiver for the OLIMPO balloon-borne telescope

    CERN Document Server

    Mahashabde, Sumedh; Bengtsson, Andreas; Andrén, Daniel; Tarasov, Michael; Salatino, Maria; de Bernardis, Paolo; Masi, Silvia; Kuzmin, Leonid

    2015-01-01

    We describe here a focal plane array of Cold-Electron Bolometer (CEB) detectors integrated in a Frequency Selective Surface (FSS) for the 350 GHz detection band of the OLIMPO balloon-borne telescope. In our architecture, the two terminal CEB has been integrated in the periodic unit cell of the FSS structure and is impedance matched to the embedding impedance seen by it and provides a resonant interaction with the incident sub-mm radiation. The detector array has been designed to operate in background noise limited condition for incident powers of 20 pW to 80 pW, making it possible to use the same pixel in both photometric and spectrometric configurations. We present high frequency and dc simulations of our system, together with fabrication details. The frequency response of the FSS array, optical response measurements with hot/cold load in front of optical window and with variable temperature black body source inside cryostat are presented. A comparison of the optical response to the CEB model and estimations...

  18. Optical sensitivity non-uniformity analysis and optimization of a tilt optical readout focal plane array

    Science.gov (United States)

    Fu, Jianyu; Shang, Haiping; Shi, Haitao; Li, Zhigang; Ou, Yi; Chen, Dapeng; Zhang, Qingchuan

    2016-02-01

    An optical readout focal plane array (FPA) usually has a differently tilted reflector/absorber at the initial state due to the micromachining technique. The angular deviation of the reflector/absorber has a strong impact on the optical sensitivity non-uniformity, which is a key factor which affects the imaging uniformity. In this study, a theoretical analysis has been developed, and it is found that the stress matching in SiO2-Aluminum (Al) bilayer leg could make a contribution towards reducing the optical sensitivity non-uniformity. Ion implantation of phosphorus (P) has been utilized to control the stress in SiO2 film. By controlling the implantation energy and dose, the stress and stress stability are modified. The optical readout FPA has been successfully fabricated with the stress-control technique based on P+ implantation. It is demonstrated that the gray response non-uniformity of optical readout FPA has decreased from 25.69% to 10.7%.

  19. High-Performance MWIR HgCdTe on Si Substrate Focal Plane Array Development

    Science.gov (United States)

    Bommena, R.; Ketharanathan, S.; Wijewarnasuriya, P. S.; Dhar, N. K.; Kodama, R.; Zhao, J.; Buurma, C.; Bergeson, J. D.; Aqariden, F.; Velicu, S.

    2015-09-01

    The development of low noise-equivalent differential temperature (NEDT), high-operability midwave infrared (MWIR) focal plane arrays (FPAs) fabricated from molecular beam epitaxial (MBE)-grown HgCdTe on Si-based substrates is reported. High-quality n-type MWIR HgCdTe layers with a cutoff wavelength of 4.90 μm at 77 K and a carrier concentration of 1-2 × 1015 cm-3 were grown on CdTe/Si substrates by MBE. Highly uniform composition and thickness over 3-inch areas were demonstrated, and low surface defect densities (voids ~5 × 102 cm-2, micro-defects ~5 × 103 cm-2) and etch pit density (~3.5 × 106 cm-2) were measured. This material was used to fabricate 320 × 256, 30 μm pitch FPAs with planar device architecture; arsenic implantation was used to achieve p-type doping. Radiometric and noise characterization was also performed. A low NEDT of 13.8 m K at 85 K for a 1 ms integration time with f/#2 optics was measured. The NEDT operability was 99% at 120 K with a mean dark current noise of 8.14 × 10-13 A/pixel. High-quality thermal images were obtained from the FPA up to a temperature of 150 K.

  20. Thermal Model for a Mars Instrument with Thermo-electric Cooled Focal Plane

    Science.gov (United States)

    Ladner, D. R.; Martin, J. P.

    2006-04-01

    Two thermal models have been developed for a low mass (1.5 kg) Mars rover arm candidate instrument that employs a thermoelectric cooler (TEC) to cool a CCD focal plane. The Mineral Identification and Composition Analyzer (MICA) is a miniature instrument that employs X-ray scattering and visual imaging to determine nondestructively the mineralogy of a rock sample in-situ. Both thermal models incorporate the key components of MICA's CCD subsystem - CCD, heat sink, and lower radiator. The System Model includes the instrument's internal heat sources, including electronics, X-ray source, TEC dissipation, and the extreme diurnal temperature excursions of the ambient Martian atmosphere (~175 K to 255 K) and sky (~130 K to 200 K), convection (wind), and solar / IR radiation. The CCD Subsystem Model includes a passive thermal switch that provides heat sink cool-down by night and isolation by day. With or without the heat switch, TEC operation provides extended life for data collection at the upper end of the CCD operating range, ~ 208 K. Model parameter variation allows the instrument designer to optimize thermal capacities, thermal resistances, and internal heater power to hold critical electronics and mechanical components within their temperature operating limits. The charting feature of either model provides mechanical design guidance to ensure acceptable conditions for data collection over the experiment timeline.

  1. A Sub-pixel Image Processing Algorithm of a Detector Based on Staring Focal Plane Array

    Institute of Scientific and Technical Information of China (English)

    LI Ya-qiong; JIN Wei-qi; XU Chao; WANG Xia

    2008-01-01

    Optical micro-scanning technology can be used to increase spatial resolution of many optical imaging systems, especially thermal imaging system. One of its key issues is relevant image processing algorithm. A fast reconstruction algo-rithm is proposed for two dimensional 2×2 micro-scanning based on the sub-pixel imaging and reconstruction principle of two-dimensional stating focal plane arrays (FPA). Specifically, three initialization methods are presented and implemented with the simulated data, their performances are compared according to image quality index . Experiment results show that, by the first initialization approach, tirnely over-sampled image can be accurately recovered, although special field diaphragm is needed. In the second initialization, the extrapolation approximation in obtaining reconstruction results is better than either bilinear interpolation or over-sampling reconstruction, without requiting any special process on system. The proposed algorithm has simple structure, low computational cost and can be realized in real-time. A high-resolution image can be obtained by low-resolution detectors. So, the algorithm has potential applications in visible light and infrared imaging area.

  2. Noise characteristics analysis of short wave infrared InGaAs focal plane arrays

    Science.gov (United States)

    Yu, Chunlei; Li, Xue; Yang, Bo; Huang, Songlei; Shao, Xiumei; Zhang, Yaguang; Gong, Haimei

    2017-09-01

    The increasing application of InGaAs short wave infrared (SWIR) focal plane arrays (FPAs) in low light level imaging requires ultra-low noise FPAs. This paper presents the theoretical analysis of FPA noise, and point out that both dark current and detector capacitance strongly affect the FPA noise. The impact of dark current and detector capacitance on FPA noise is compared in different situations. In order to obtain low noise performance FPAs, the demand for reducing detector capacitance is higher especially when pixel pitch is smaller, integration time is shorter, and integration capacitance is larger. Several InGaAs FPAs were measured and analyzed, the experiments' results could be well fitted to the calculated results. The study found that the major contributor of FPA noise is coupled noise with shorter integration time. The influence of detector capacitance on FPA noise is more significant than that of dark current. To investigate the effect of detector performance on FPA noise, two kinds of photodiodes with different concentration of the absorption layer were fabricated. The detectors' performance and noise characteristics were measured and analyzed, the results are consistent with that of theoretical analysis.

  3. The scintillating fiber focal plane detector for the use of Kaos as a double arm spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ayerbe Gayoso, Carlos Antonio

    2012-05-25

    calculating the transfer matrix of track parameters from the fiber detector focal plane to the primary vertex. This transfer matrix has been calculated to first order using beam transport optics and has been checked by quasielastic scattering off a carbon target, where the full kinematics is determined by measuring the recoil proton momentum. The reconstruction accuracy for the emission parameters at the quasielastic vertex was found to be on the order of 0.3 % in first test realized. The design, construction process, commissioning, testing and characterization of the fiber hodoscope are presented in this work which has been developed at the Institut fuer Kernphysik of the Johannes Gutenberg - Universitaet Mainz.

  4. On the reliability of focal plane solutions using first motion readings

    Science.gov (United States)

    Hofstetter, A.

    2014-01-01

    First motion fault plane solutions provide invaluable important information on the mechanism of seismogenic faults and the orientation of the local stress field. However, there are severe limitations and shortcomings regarding the reliability of the calculated solution and how accurately it reflects the real earthquake mechanism. In this study, we examine the dependence of the three mechanisms of ideal strike slip, normal, and thrust on different quality estimators, i.e., event location, velocity model, and reverse polarity stations. We intentionally perturb the original fault plane solutions by changing only one of the parameters that control the solution at a time and compare the perturbed solutions with the real one. Finally, we randomly perturb all the parameters for each earthquake in a large set of events. We then discuss the effect of the perturbations on the reliability of the solution.

  5. Polydendrocytes display large lineage plasticity following focal cerebral ischemia.

    Directory of Open Access Journals (Sweden)

    Pavel Honsa

    Full Text Available Polydendrocytes (also known as NG2 glial cells constitute a fourth major glial cell type in the adult mammalian central nervous system (CNS that is distinct from other cell types. Although much evidence suggests that these cells are multipotent in vitro, their differentiation potential in vivo under physiological or pathophysiological conditions is still controversial.To follow the fate of polydendrocytes after CNS pathology, permanent middle cerebral artery occlusion (MCAo, a commonly used model of focal cerebral ischemia, was carried out on adult NG2creBAC:ZEG double transgenic mice, in which enhanced green fluorescent protein (EGFP is expressed in polydendrocytes and their progeny. The phenotype of the EGFP(+ cells was analyzed using immunohistochemistry and the patch-clamp technique 3, 7 and 14 days after MCAo. In sham-operated mice (control, EGFP(+ cells in the cortex expressed protein markers and displayed electrophysiological properties of polydendrocytes and oligodendrocytes. We did not detect any co-labeling of EGFP with neuronal, microglial or astroglial markers in this region, thus proving polydendrocyte unipotent differentiation potential under physiological conditions. Three days after MCAo the number of EGFP(+ cells in the gliotic tissue dramatically increased when compared to control animals, and these cells displayed properties of proliferating cells. However, in later phases after MCAo a large subpopulation of EGFP(+ cells expressed protein markers and electrophysiological properties of astrocytes that contribute to the formation of glial scar. Importantly, some EGFP(+ cells displayed membrane properties typical for neural precursor cells, and moreover these cells expressed doublecortin (DCX--a marker of newly-derived neuronal cells. Taken together, our data indicate that polydendrocytes in the dorsal cortex display multipotent differentiation potential after focal ischemia.

  6. Performance of 128×128 solar-blind AlGaN ultraviolet focal plane arrays

    Science.gov (United States)

    Yuan, Yongang; Zhang, Yan; Liu, Dafu; Chu, Kaihui; Wang, Ling; Li, Xiangyang

    2009-07-01

    Ozone layer intensively absorbs 240nm to 285 nm incidence, when the sunshine goes through stratospheric. There is almost no UVC (200nm-280nm) band radiation existing below stratospheric. Because the radiation target presents a strong contrast between atmosphere and background, solar-blind band radiation is very useful. Wide band gap materials, especially III-V nitride materials, have attracted extensive interest. The direct band gap of GaN and A1N is 3.4 and 6.2 eV, respectively. Since they are miscible with each other and form a complete series of AlGaN alloys, AlGaN has direct band gaps from 3.4 to 6.2 eV, corresponding to cutoff wavelengths from 365 to 200 nm. A back-illuminated hybrid FPA has been developed by Shanghai Institute of Technical Physics Chinese Academy of Science. This paper reports the performance of the 128x128 solar-blind AlGaN UV Focal Plane Arrays (FPAs). More and more a CTIA (capacitivetransimpedance) readout circuit architecture has been proven to be well suited for AlGaN detectors arrays. The bared readout circuit was first tested to find out optimal analog reference voltage. Second, this ROIC was tested in a standard 20-pin shielded dewar at 115 K to 330K. Then, a new test system was set up to obtain test UV FPA noise, swing voltage, data valid time, operating speed, dynamic range, UV response etc. The results show that 128x128 back-illuminated AlGaN PIN detector SNR is as high as 74db at the speed of above30 frame per second. Also, some noise test method is mentioned.

  7. Kepler Commissioning Data for Measurement of the Pixel Response Function and Focal Plane Geometry

    Science.gov (United States)

    Bryson, Stephen T.

    2017-01-01

    This document describes the Kepler PRF/FPG data release. This data was taken on April 27-29, 2009, during Kepler's commissioning phase in order to measure the pixel response function (PRF) (Bryson et al., 2010a) and focal plane geometry (FPG) (Tenenbaum and Jenkins, 2010). 33,424 stellar targets were observed for 243 long cadences, each with a duration of 14.7 minutes (half the duration of a normal Kepler long cadence). During these 243 cadences the Kepler photometer was moved, pointing in a dither pattern to facilitate PRF measurement. Motion occurred during the even cadences (second, fourth, etc.), with the telescope in stable fine point at each pointing in the dither pattern during the odd cadences (first, third, etc.). The first and last cadences were at the center of the dither pattern. Motion cadences are included in this release, but they do not contain any data. For details on how this data was used to derive the Kepler PRF and FPG models, see Bryson et al. (2010a) and Tenenbaum and Jenkins (2010). Descriptions of the PRF and FPG models are found in Thompson et al. (2016), x2.3.5.17 and x2.3.5.16 respectively. The data in this release can be used to recompute the Kepler PRF and FPG. Such a reconstruction, however, would not reflect measured seasonal changes in the PRF described in Van Cleve et al. (2016b), x5.2.The dither pattern is shown in Figure 1. The crosses show the commanded pointings and the circles show the measured pointings. Measured pointings are different from the commanded pointings due to the early state of calibration of the fine guidance sensors during commissioning (Van Cleve et al., 2016a). The measured offsets from the center of the pattern are given in RADEC offsets and pixel offsets in Table 1. The order of the offsets was randomized during data collection to avoid time-dependent systematics.

  8. Vacuum packaging of InGaAs focal plane array with four-stage thermoelectric cooler

    Science.gov (United States)

    Mo, De-feng; Liu, Da-fu; Yang, Li-yi; Xu, Qin-fei; Li, Xue

    2013-09-01

    The InGaAs focal plane array (FPA) detectors, covering the near-infrared 1~2.4 μm wavelength range, have been developed for application in space-based spectroscopy of the Earth atmosphere. This paper shows an all-metal vacuum package design for area array InGaAs detector of 1024×64 pixels, and its architecture will be given. Four-stage thermoelectric cooler (TEC) is used to cool down the FPA chip. To acquire high heat dissipation for TEC's Joule-heat, tungsten copper (CuW80) and kovar (4J29) is used as motherboard and cavity material respectively which joined by brazing. The heat loss including conduction, convection and radiation is analyzed. Finite element model is established to analyze the temperature uniformity of the chip substrate which is made of aluminum nitride (AlN). The performance of The TEC with and without heat load in vacuum condition is tested. The results show that the heat load has little influence to current-voltage relationship of TEC. The temperature difference (ΔT) increases as the input current increases. A linear relationship exists between heat load and ΔT of the TEC. Theoretical analysis and calculation show that the heat loss of radiation and conduction is about 187 mW and 82 mW respectively. Considering the Joule-heat of readout circuit and the heat loss of radiation and conduction, the FPA for a 220 K operation at room temperature can be achieved. As the thickness of AlN chip substrate is thicker than 1 millimeter, the temperature difference can be less than 0.3 K.

  9. On-sky performance evaluation and calibration of a polarization-sensitive focal plane array

    Science.gov (United States)

    Vorobiev, Dmitry; Ninkov, Zoran; Brock, Neal; West, Ray

    2016-07-01

    The advent of pixelated micropolarizer arrays (MPAs) has facilitated the development of polarization-sensitive focal plane arrays (FPAs) based on charge-coupled devices (CCDs) and active pixel sensors (APSs), which are otherwise only able to measure the intensity of light. Polarization sensors based on MPAs are extremely compact, light-weight, mechanically robust devices with no moving parts, capable of measuring the degree and angle of polarization of light in a single snapshot. Furthermore, micropolarizer arrays based on wire grid polarizers (so called micro-grid polarizers) offer extremely broadband performance, across the optical and infrared regimes. These devices have potential for a wide array of commercial and research applications, where measurements of polarization can provide critical information, but where conventional polarimeters could be practically implemented. To date, the most successful commercial applications of these devices are 4D Technology's PhaseCam laser interferometers and PolarCam imaging polarimeters. Recently, MPA-based polarimeters have been identified as a potential solution for space-based telescopes, where the small size, snapshot capability and low power consumption (offered by these devices) are extremely desirable. In this work, we investigated the performance of MPA-based polarimeters designed for astronomical polarimetry using the Rochester Institute of Technology Polarization Imaging Camera (RITPIC). We deployed RITPIC on the 0.9 meter SMARTS telescope at the Cerro Tololo Inter-American Observatory and observed a variety of astronomical objects (calibration stars, variable stars, reflection nebulae and planetary nebulae). We use our observations to develop calibration procedures that are unique to these devices and provide an estimate for polarimetric precision that is achievable.

  10. High temperature operation In1-xAlxSb infrared focal plane

    Science.gov (United States)

    Lyu, Yanqiu; Si, Junjie; Cao, Xiancun; Zhang, Liang; Peng, Zhenyu; Ding, Jiaxin; Yao, Guansheng; Zhang, Xiaolei; Reobrazhenskiy, Valeriy

    2016-05-01

    A high temperature operation mid-wavelength 128×128 infrared focal plane arrays (FPA) based on low Al component In1-xAlxSb was presented in this work. InAlSb materials were grown on InSb (100) substrates using MBE technology, which was confirmed by XRD and AFM analyses. We have designed and grown two structures with and without barrier. The pixel of the detector had a conventional PIN structure with a size of 50μmx50μm. The device fabrication process consisted of mesa etching, passivation, metallization and flip-chip hybridization with readout integrated circuit (ROIC), epoxy backfill, lap and polish. Diode resistance, imaging, NETD and operability results are presented for a progression of structures that reduce the diode leakage current as the temperature is raised above 80K. These include addition of a thin region of InAlSb to reduce p-contact leakage current, and construction of the whole device from InAlSb to reduce thermal generation in the active region of the detector. An increase in temperature to 110K, whilst maintaining full 80K performance, is achieved. The I-V curves were measured at different temperature. Quantum efficiency, pixel operability, non-uniformity, and the mean NETD values of the FPAs were measured at 110K. This gives the prospect of significant benefits for the cooling systems, including, for example, use of argon in Joule-Thomson coolers or an increase in the life and/or decrease in the cost, power consumption and cool-down time of Stirling engines by several tens of percent.

  11. Development of high performance SWIR InGaAs focal plane array

    Science.gov (United States)

    Nagi, Richie; Bregman, Jeremy; Mizuno, Genki; Oduor, Patrick; Olah, Robert; Dutta, Achyut K.; Dhar, Nibir K.

    2015-05-01

    Banpil Photonics has developed a novel InGaAs based photodetector array for Short-Wave Infrared (SWIR) imaging, for the most demanding security, defense, and machine vision applications. These applications require low noise from both the detector and the readout integrated circuit arrays. In order to achieve high sensitivity, it is crucial to minimize the dark current generated by the photodiode array. This enables the sensor to function in extremely low light situations, which enables it to successfully exploit the benefits of the SWIR band. In addition to minimal dark current generation, it is essential to develop photodiode arrays with higher operating temperatures. This is critical for reducing the power consumption of the device, as less energy is spent in cooling down the focal plane array (in order to reduce the dark current). We at Banpil Photonics are designing, simulating, fabricating and testing SWIR InGaAs arrays, and have achieved low dark current density at room temperature. This paper describes Banpil's development of the photodetector array. We also highlight the fabrication technique used to reduce the amount of dark current generated by the photodiode array, in particular the surface leakage current. This technique involves the deposition of strongly negatively doped semiconductor material in the area between the pixels. This process reduces the number of dangling bonds present on the edges of each pixel, which prevents electrons from being swept across the surface of the pixels. This in turn drastically reduces the amount of surface leakage current at each pixel, which is a major contributor towards the total dark current. We present the optical and electrical characterization data, as well as the analysis that illustrates the dark current mechanisms. Also highlighted are the challenges and potential opportunities for further reduction of dark current, while maintaining other parameters of the photodiode array, such as size, weight, temperature

  12. A CMOS imager using focal-plane pinhole effect for confocal multibeam scanning microscopy

    Science.gov (United States)

    Seo, Min-Woong; Wang, An; Li, Zhuo; Yasutomi, Keita; Kagawa, Keiichiro; Kawahito, Shoji

    2012-03-01

    A CMOS imager for confocal multi-beam scanning microscopy, where the pixel itself works as a pinhole, is proposed. This CMOS imager is suitable for building compact, low-power, and confocal microscopes because the complex Nipkow disk with a precisely aligned pinhole array can be omitted. The CMOS imager is composed of an array of sub-imagers, and can detect multiple beams at the same time. To achieve a focal-plane pinhole effect, only one pixel in each subimager, which is at the conjugate position of a light spot, accumulates the photocurrent, and the other pixels are unread. This operation is achieved by 2-dimensional vertical and horizontal shift registers. The proposed CMOS imager for the confocal multi-beam scanning microscope system was fabricated in 0.18-μm standard CMOS technology with a pinned photodiode option. The total area of the chip is 5.0mm × 5.0mm. The number of effective pixels is 256(Horizontal) × 256(Vertical). The pixel array consists of 32(H) × 32(V) sub-imagers each of which has 8(H) × 8(V) pixels. The pixel is an ordinary 4-transistor active pixel sensor using a pinned photodiode and the pixel size is 7.5μm × 7.5μm with a fillfactor of 45%. The basic operations such as normal image acquisition and selective pixel readout were experimentally confirmed. The sensitivity and the pixel conversion gain were 25.9 ke-/lx•sec and 70 μV/e- respectively.

  13. The Focal Plane Package of the Solar Optical telescope on Solar B

    Science.gov (United States)

    Tarbell, Theodore D.

    2006-06-01

    The Solar-B satellite will be launched into a full-sun low-earth orbit in the fall of 2006 from Japan's Uchinoura Space center. It includes the 50-cm diameter Solar Optical Telescope with its Focal Plane Package (FPP), for near-UV and visible observations of the photosphere and chromosphere at very high (diffraction limited) angular resolution. The FPP has a Spectro-Polarimeter (SP) for precision measurements of photospheric vector magnetic fields over a 160 x 320 arcsecond field of view; a Narrowband Filter Imager (NFI) with a tunable birefringent filter for magnetic, Doppler, and intensity maps over the same field of view; and a Broadband Filter Imager (BFI) for highest resolution images in six wavelengths (G band, Ca II H, continua, etc.) over two-thirds of that field of view. A polarization modulator in the telescope allows measurement of Stokes parameters at all wavelengths in the SP and NFI. The NFI wavelengths include both photospheric and chromospheric lines (Fe I, Mg b, Na D, H-alpha). All images are stabilized by a tip-tilt mirror and correlation tracker. This presentation will include pictures and description of the instrument, results from calibration and sun testing, portions of the draft science plan, and some preliminary JOP's. Solar-B is an international cooperative mission between JAXA/ISAS of Japan, NASA of the United States, and PPARC of the United Kingdom. The Solar Optical Telescope has been developed by the National Astronomical Observatory of Japan, Mitsubishi Electric Company, and JAXA/ISAS. The FPP has been developed by the Lockheed Martin Advanced Technology Center, High Altitude Observatory, and NASA.

  14. Compton polarimeter as a focal plane detector for hard X-ray telescope: sensitivity estimation with Geant4 simulations

    Science.gov (United States)

    Chattopadhyay, T.; Vadawale, S. V.; Pendharkar, J.

    2013-04-01

    X-ray polarimetry can be an important tool for investigating various physical processes as well as their geometries at the celestial X-ray sources. However, X-ray polarimetry has not progressed much compared to the spectroscopy, timing and imaging mainly due to the extremely photon-hungry nature of X-ray polarimetry leading to severely limited sensitivity of X-ray polarimeters. The great improvement in sensitivity in spectroscopy and imaging was possible due to focusing X-ray optics which is effective only at the soft X-ray energy range. Similar improvement in sensitivity of polarisation measurement at soft X-ray range is expected in near future with the advent of GEM based photoelectric polarimeters. However, at energies >10 keV, even spectroscopic and imaging sensitivities of X-ray detector are limited due to lack of focusing optics. Thus hard X-ray polarimetry so far has been largely unexplored area. On the other hand, typically the polarisation degree is expected to increase at higher energies as the radiation from non-thermal processes is dominant fraction. So polarisation measurement in hard X-ray can yield significant insights into such processes. With the recent availability of hard X-ray optics (e.g. with upcoming NuSTAR, Astro-H missions) which can focus X-rays from 5 KeV to 80 KeV, sensitivity of X-ray detectors in hard X-ray range is expected to improve significantly. In this context we explore feasibility of a focal plane hard X-ray polarimeter based on Compton scattering having a thin plastic scatterer surrounded by cylindrical array scintillator detectors. We have carried out detailed Geant4 simulation to estimate the modulation factor for 100 % polarized beam as well as polarimetric efficiency of this configuration. We have also validated these results with a semi-analytical approach. Here we present the initial results of polarisation sensitivities of such focal plane Compton polarimeter coupled with the reflection efficiency of present era hard X

  15. (abstract) 9 (micro)m Cutoff 640x480 Quantum Well Infrared Photodetector (QWIP) Focal Plane Array Camera

    Science.gov (United States)

    Gunapala, S. D.; Sundaram, M.; Liu, J. K.; Bandara, S. V.; Shott, C. A.; Hoelter, T.

    1997-01-01

    Long wavelength infrared (LWIR) detectors, 8 (micro)m to 12 (micro)m, are of great interest for a variety of ground-based and space-borne applications. These applications have placed stringent requirements on the performance of the infrared detectors and arrays including high detectivity, low dark current, uniformity, radiation hardness, and low power dissipation. I will discuss the development and progress of GaAs based long-wavelength quantum well infrared photodetectors (QWIPs) to meet those stringent requirements and the demonstration of a 9 (micro)m cutoff 640x480 QUIP focal plane array camera. The noise equivalent temperature difference of the focal plane array is 25 mK at 300 K background and the operating temperature is 70 K.

  16. Angular acceptance analysis of an infrared focal plane array with a built-in stationary Fourier transform spectrometer.

    Science.gov (United States)

    Gillard, Frédéric; Ferrec, Yann; Guérineau, Nicolas; Rommeluère, Sylvain; Taboury, Jean; Chavel, Pierre

    2012-06-01

    Stationary Fourier transform spectrometry is an interesting concept for building reliable field or embedded spectroradiometers, especially for the mid- and far- IR. Here, a very compact configuration of a cryogenic stationary Fourier transform IR (FTIR) spectrometer is investigated, where the interferometer is directly integrated in the focal plane array (FPA). We present a theoretical analysis to explain and describe the fringe formation inside the FTIR-FPA structure when illuminated by an extended source positioned at a finite distance from the detection plane. The results are then exploited to propose a simple front lens design compatible with a handheld package.

  17. Portable sequential multicolor thermal imager based on a MCT 384 x 288 focal plane array

    Science.gov (United States)

    Breiter, Rainer; Cabanski, Wolfgang A.; Mauk, Karl-Heinz; Rode, Werner; Ziegler, Johann

    2001-10-01

    AIM has developed a sequential multicolor thermal imager to provide customers with a test system to realize real-time spectral selective thermal imaging. In contrast to existing PC based laboratory units, the system is miniaturized with integrated signal processing like non-uniformity correction and post processing functions such as image subtraction of different colors to allow field tests in military applications like detection of missile plumes or camouflaged targets as well as commercial applications like detection of chemical agents, pollution control, etc. The detection module used is a 384 X 288 mercury cadmium telluride (MCT) focal plane array (FPA) available in the mid wave (MWIR) or long wave spectral band LWIR). A compact command and control electronics (CCE) provides clock and voltage supply for the detector as well as 14 bit deep digital conversion of the analog detector output. A continuous rotating wheel with four facets for filters provides spectral selectivity. The customer can choose between various types of filter characteristics, e.g. a 4.2 micrometer bandpass filter for CO2 detection in the MWIR band. The rotating wheel can be synchronized to an external source giving the rotation speed, typical 25 l/s. A position sensor generates the four frame start signals for synchronous operation of the detector -- 100 Hz framerate for the four frames per rotation. The rotating wheel is exchangeable for different configurations and also plates for a microscanner operation to improve geometrical resolution are available instead of a multicolor operation. AIM's programmable MVIP image processing unit is used for signal processing like non- uniformity correction and controlling the detector parameters. The MVIP allows to output the four subsequent images as four quarters of the video screen to prior to any observation task set the integration time for each color individually for comparable performance in each spectral color and after that also to determine

  18. The development of InGaAs short wavelength infrared focal plane arrays with high performance

    Science.gov (United States)

    Li, Xue; Gong, Haimei; Fang, Jiaxiong; shao, Xiumei; Tang, Hengjing; Huang, Songlei; Li, Tao; Huang, Zhangcheng

    2017-01-01

    High performance, various specifications InGaAs focal plane arrays(FPAs) were studied in Shanghai Institute of Technical Physics (SITP). On the one hand, the typical linear 256 × 1, 512 × 1 and 1024 × 1 FPAs were obtained for response wavelengths from 0.9 μm to 1.7 μm. The typical 320 × 256 FPAs and special sizes 512 × 128, 512 × 256 FPAs for the near infrared multi-spectral imaging were studied. The performance of InGaAs FPAs from 0.9 μm to 1.7 μm has improved enormously. The average peak detectivity, the response non-uniformity and non-operable pixel of the FPAs are superior to 3 × 1012 cm Hz1/2/W, 5% and 1% at the room temperature. On the other hand, the development of the extended InGaAs FPAs was also focused in SITP. The dark current of InGaAs detectors with the response wavelength from 1.0 μm to 2.5 μm decreases to about 10 nA/cm2 at 200 K. The dark current mechanisms for extended InGaAs detectors were studied by P/A photodiodes. The special sizes 512 × 256 FPAs has been fabricated since 2011. The average peak detectivity, the response non-uniformity and non-operable pixel of the FPAs are superior to 5 × 1011 cm Hz1/2/W, 8% and 2% at 200 K. In order to verify the performance of FPAs, the short wavelength infrared lens was used to form optical imaging system. The buildings, water, trees are sharply imaged by 320 × 256 FPAs with 0.9-1.7 μm wavelength and 512 × 1 FPAs with 0.9-2.5 μm wavelength at about hundreds of meters distance as target at daylight.

  19. Pleiades HR in Flight Geometrical Calibration : Location and Mapping of the Focal Plane

    Science.gov (United States)

    de Lussy, F.; Greslou, D.; Dechoz, C.; Amberg, V.; Delvit, J. M.; Lebegue, L.; Blanchet, G.; Fourest, S.

    2012-07-01

    The Pleiades system, ORFEO system optical component (Optical and Radar Federated Earth Observation) consists of a constellation of two satellites for very High Resolution panchromatic and multispectral optical observation of the Earth. Its mission is to cover all European civilian needs (mapping, tracking floods and fires) and defence in the category of metric resolution: 0.7m Nadir. The first Pleiades satellite was launched at the end of last year. One of the key objectives of the Pleiades HR (PHR) project is to achieve a location accuracy that will allow the use of images in GIS (Geographical Information System) without geometrical model improvement by refining on ground control points. The image location without refined model was specified with the precision of the most commonly used tool ie the civil GPS. So the location accuracy has been specified at less than 12m for 90% of the images on a nominal satellite configuration. Very special care has been taken all along the PHR project realization to achieve this very good location accuracy. The final touch is given during the in-orbit commissioning phase which lasts until June 2012. The geometric quality implies to tune the parameters involved in the geolocation model (geometric calibration): besides attitude and orbit restitution tuning (not considered here), it consists in estimating the biases between the instrument orientation and the AOCS reference frame, and also the sight line of each detector in the focal plane. This is called static geometrical model. The analysis of dynamic perturbations outside of the model are the second most important image quality objective of in-flight commissioning, not described in this paper. Finally "image quality assessment" consists in evaluating the image quality obtained in the final products. For geolocation model, it is quantified by the absolute geolocation and the pointing accuracies, and it is a main contributor in length alteration and planimetric and altimetric

  20. THE IMAGING PROPERTIES OF THE GAS PIXEL DETECTOR AS A FOCAL PLANE POLARIMETER

    Energy Technology Data Exchange (ETDEWEB)

    Fabiani, S.; Costa, E.; Del Monte, E.; Muleri, F.; Soffitta, P.; Rubini, A. [INAF-IAPS, via del Fosso del Cavaliere 100, I-00133 Roma (Italy); Bellazzini, R.; Brez, A.; De Ruvo, L.; Minuti, M.; Pinchera, M.; Sgró, C.; Spandre, G. [INFN Sezione di Pisa, Largo B. Pontecorvo, 3, I-56127 Pisa (Italy); Spiga, D.; Tagliaferri, G.; Pareschi, G.; Basso, S.; Citterio, O. [INAF-Osservatorio Astronomico di Brera, via Brera 28, I-20121 Milano (Italy); Burwitz, V.; Burkert, W., E-mail: sergio.fabiani@iaps.inaf.it [Max-Planck-Institut für extraterrestrische Physik, Gautinger Str. 45, D-82061 Neuired (Germany); and others

    2014-06-01

    X-rays are particularly suited to probing the physics of extreme objects. However, despite the enormous improvements of X-ray astronomy in imaging, spectroscopy, and timing, polarimetry remains largely unexplored. We propose the photoelectric polarimeter Gas Pixel Detector (GPD) as a candidate instrument to fill the gap created by more than 30 yr without measurements. The GPD, in the focus of a telescope, will increase the sensitivity of orders of magnitude. Moreover, since it can measure the energy, the position, the arrival time, and the polarization angle of every single photon, it allows us to perform polarimetry of subsets of data singled out from the spectrum, the light curve, or an image of the source. The GPD has an intrinsic, very fine imaging capability, and in this work we report on the calibration campaign carried out in 2012 at the PANTER X-ray testing facility of the Max-Planck-Institut für extraterrestrische Physik of Garching (Germany) in which, for the first time, we coupled it with a JET-X optics module with a focal length of 3.5 m and an angular resolution of 18 arcsec at 4.5 keV. This configuration was proposed in 2012 aboard the X-ray Imaging Polarimetry Explorer (XIPE) in response to the ESA call for a small mission. We derived the imaging and polarimetric performance for extended sources like pulsar wind nebulae and supernova remnants as case studies for the XIPE configuration and also discuss possible improvements by coupling the detector with advanced optics that have a finer angular resolution and larger effective areas to study extended objects with more detail.

  1. The Imaging Properties of the Gas Pixel Detector as a Focal Plane Polarimeter

    Science.gov (United States)

    Fabiani, S.; Costa, E.; Del Monte, E.; Muleri, F.; Soffitta, P.; Rubini, A.; Bellazzini, R.; Brez, A.; de Ruvo, L.; Minuti, M.; Pinchera, M.; Sgró, C.; Spandre, G.; Spiga, D.; Tagliaferri, G.; Pareschi, G.; Basso, S.; Citterio, O.; Burwitz, V.; Burkert, W.; Menz, B.; Hartner, G.

    2014-06-01

    X-rays are particularly suited to probing the physics of extreme objects. However, despite the enormous improvements of X-ray astronomy in imaging, spectroscopy, and timing, polarimetry remains largely unexplored. We propose the photoelectric polarimeter Gas Pixel Detector (GPD) as a candidate instrument to fill the gap created by more than 30 yr without measurements. The GPD, in the focus of a telescope, will increase the sensitivity of orders of magnitude. Moreover, since it can measure the energy, the position, the arrival time, and the polarization angle of every single photon, it allows us to perform polarimetry of subsets of data singled out from the spectrum, the light curve, or an image of the source. The GPD has an intrinsic, very fine imaging capability, and in this work we report on the calibration campaign carried out in 2012 at the PANTER X-ray testing facility of the Max-Planck-Institut für extraterrestrische Physik of Garching (Germany) in which, for the first time, we coupled it with a JET-X optics module with a focal length of 3.5 m and an angular resolution of 18 arcsec at 4.5 keV. This configuration was proposed in 2012 aboard the X-ray Imaging Polarimetry Explorer (XIPE) in response to the ESA call for a small mission. We derived the imaging and polarimetric performance for extended sources like pulsar wind nebulae and supernova remnants as case studies for the XIPE configuration and also discuss possible improvements by coupling the detector with advanced optics that have a finer angular resolution and larger effective areas to study extended objects with more detail.

  2. Effect of the focal plane position on CO2 laser beam cutting of injection molded polycarbonate sheets

    Science.gov (United States)

    Moradi, Mahmoud; Mehrabi, Omid; Azdast, Taher; Benyounis, Khaled Y.

    2016-11-01

    In the present research, the effect of laser beam focal plane position (FPP) on the kerf quality of the polycarbonate laser cutting is investigated. Low power CO2 laser is used as the heat source of the cutting runs. In the experiments, FPP is varied from 0 to -4mm while other processing parameters (i.e. laser power, cutting speed and gas pressure) are considered constant. Upper and lower kerf width, kerf taper, upper heat affected zone and surface roughness of the kerf wall are also considered as the responses. Observations signified that reducing the position of the laser beam focal point from zero to - 3mm reduces the upper and lower kerf width. However reducing FPP below -3mm leads to an increase in the kerf width. Results also reveals that upper heat affected zone value reduces by reduction in FPP. Moreover the best kerf wall surface roughness occurred at FPP= -3mm.

  3. Development of a hard x-ray focal plane compton polarimeter: a compact polarimetric configuration with scintillators and Si photomultipliers

    Science.gov (United States)

    Chattopadhyay, T.; Vadawale, S. V.; Goyal, S. K.; Mithun, N. P. S.; Patel, A. R.; Shukla, R.; Ladiya, T.; Shanmugam, M.; Patel, V. R.; Ubale, G. P.

    2016-02-01

    X-ray polarization measurement of cosmic sources provides two unique parameters namely degree and angle of polarization which can probe the emission mechanism and geometry at close vicinity of the compact objects. Specifically, the hard X-ray polarimetry is more rewarding because the sources are expected to be intrinsically highly polarized at higher energies. With the successful implementation of Hard X-ray optics in NuSTAR, it is now feasible to conceive Compton polarimeters as focal plane detectors. Such a configuration is likely to provide sensitive polarization measurements in hard X-rays with a broad energy band. We are developing a focal plane hard X-ray Compton polarimeter consisting of a plastic scintillator as active scatterer surrounded by a cylindrical array of CsI(Tl) scintillators. The scatterer is 5 mm diameter and 100 mm long plastic scintillator (BC404) viewed by normal PMT. The photons scattered by the plastic scatterer are collected by a cylindrical array of 16 CsI(Tl) scintillators (5 mm × 5 mm × 150 mm) which are read by Si Photomultiplier (SiPM). Use of the new generation SiPMs ensures the compactness of the instrument which is essential for the design of focal plane detectors. The expected sensitivity of such polarimetric configuration and complete characterization of the plastic scatterer, specially at lower energies have been discussed in [11, 13]. In this paper, we characterize the CsI(Tl) absorbers coupled to SiPM. We also present the experimental results from the fully assembled configuration of the Compton polarimeter.

  4. The Mid-Infrared Instrument for the James Webb Space Telescope, VIII: The MIRI Focal Plane System

    CERN Document Server

    Ressler, M E; Franklin, B R; Mahoney, J C; Thelen, M P; Bouchet, P; Colbert, J W; Cracraft, Misty; Dicken, D; Gastaud, R; Goodson, G B; Eccleston, Paul; Moreau, V; Rieke, G H; Schneider, Analyn

    2015-01-01

    We describe the layout and unique features of the focal plane system for MIRI. We begin with the detector array and its readout integrated circuit (combining the amplifier unit cells and the multiplexer), the electronics, and the steps by which the data collection is controlled and the output signals are digitized and delivered to the JWST spacecraft electronics system. We then discuss the operation of this MIRI data system, including detector readout patterns, operation of subarrays, and data formats. Finally, we summarize the performance of the system, including remaining anomalies that need to be corrected in the data pipeline.

  5. The coronagraphic Modal Wavefront Sensor: a hybrid focal-plane sensor for the high-contrast imaging of circumstellar environments

    CERN Document Server

    Wilby, Michael J; Snik, Frans; Korkiakoski, Visa; Pietrow, Alexander G M

    2016-01-01

    The raw coronagraphic performance of current high-contrast imaging instruments is limited by the presence of a quasi-static speckle (QSS) background, resulting from instrumental non-common path errors (NCPEs). Rapid development of efficient speckle subtraction techniques in data reduction has enabled final contrasts of up to 10-6 to be obtained, however it remains preferable to eliminate the underlying NCPEs at the source. In this work we introduce the coronagraphic Modal Wavefront Sensor (cMWS), a new wavefront sensor suitable for real-time NCPE correction. This pupil-plane optic combines the apodizing phase plate coronagraph with a holographic modal wavefront sensor, to provide simultaneous coronagraphic imaging and focal-plane wavefront sensing using the science point spread function. We first characterise the baseline performance of the cMWS via idealised closed-loop simulations, showing that the sensor successfully recovers diffraction-limited coronagraph performance over an effective dynamic range of +/...

  6. Resolution and mass range performance in distance-of-flight mass spectrometry with a multichannel focal-plane camera detector.

    Science.gov (United States)

    Graham, Alexander W G; Ray, Steven J; Enke, Christie G; Felton, Jeremy A; Carado, Anthony J; Barinaga, Charles J; Koppenaal, David W; Hieftje, Gary M

    2011-11-15

    Distance-of-flight mass spectrometry (DOFMS) is a velocity-based mass-separation technique in which ions are separated in space along the plane of a spatially selective detector. In the present work, a solid-state charge-detection array, the focal-plane camera (FPC), was incorporated into the DOFMS platform. Use of the FPC with our DOFMS instrument resulted in improvements in analytical performance, usability, and versatility over a previous generation instrument that employed a microchannel-plate/phosphor DOF detector. Notably, FPC detection provided resolution improvements of at least a factor of 2, with typical DOF linewidths of 300 μm (R((fwhm)) = 1000). The merits of solid-state detection for DOFMS are evaluated, and methods to extend the DOFMS mass range are considered.

  7. A case of hepatocellular carcinoma arising within large focal nodular hyperplasia with review of the literature

    Institute of Scientific and Technical Information of China (English)

    Theodoros Petsas; Athanassios Tsamandas; Irene Tsota; Dionisios Karavias; Chrysoula Karatza; Vassilios Vassiliou; Dimitrios Kardamakis

    2006-01-01

    Focal nodular hyperplasia (FNH) is a relatively rare benign hepatic tumor, usually presenting as a solitary lesion; however, multiple localizations have also been described. The association of FNH with other hepatic lesions, such as adenomas and haemangiomas has been reported by various authors. We herein report a case of a hepatocellular carcinoma arising within a large focal nodular hyperplasia, in a young female patient.

  8. Development of a Hard X-ray focal plane Compton Polarimeter: A compact polarimetric configuration with Scintillators and Si photomultipliers

    CERN Document Server

    Chattopadhyay, T; Goyal, S K; S., Mithun N P; Patel, A R; Shukla, R; Ladiya, T; Shanmugam, M; Patel, V R; Ubale, G P

    2015-01-01

    X-ray polarization measurement of cosmic sources provides two unique parameters namely degree and angle of polarization which can probe the emission mechanism and geometry at close vicinity of the compact objects. Specifically, the hard X-ray polarimetry is more rewarding because the sources are expected to be intrinsically highly polarized at higher energies. With the successful implementation of Hard X-ray optics in NuSTAR, it is now feasible to conceive Compton polarimeters as focal plane detectors. Such a configuration is likely to provide sensitive polarization measurements in hard X-rays with a broad energy band. We are developing a focal plane hard X-ray Compton polarimeter consisting of a plastic scintillator as active scatterer surrounded by a cylindrical array of CsI(Tl) scintillators. The scatterer is 5 mm diameter and 100 mm long plastic scintillator (BC404) viewed by normal PMT. The photons scattered by the plastic scatterer are collected by a cylindrical array of 16 CsI(Tl) scintillators (5 mm x...

  9. Focal plane generation of multi-resolution and multi-scale image representation for low-power vision applications

    Science.gov (United States)

    Fernández-Berni, J.; Carmona-Galán, R.; Carranza-González, L.; Zarándy, A.; Rodríguez-Vázquez, Á.

    2011-06-01

    Early vision stages represent a considerably heavy computational load. A huge amount of data needs to be processed under strict timing and power requirements. Conventional architectures usually fail to adhere to the specifications in many application fields, especially when autonomous vision-enabled devices are to be implemented, like in lightweight UAVs, robotics or wireless sensor networks. A bioinspired architectural approach can be employed consisting of a hierarchical division of the processing chain, conveying the highest computational demand to the focal plane. There, distributed processing elements, concurrent with the photosensitive devices, influence the image capture and generate a pre-processed representation of the scene where only the information of interest for subsequent stages remains. These focal-plane operators are implemented by analog building blocks, which may individually be a little imprecise, but as a whole render the appropriate image processing very efficiently. As a proof of concept, we have developed a 176x144-pixel smart CMOS imager that delivers lighter but enriched representations of the scene. Each pixel of the array contains a photosensor and some switches and weighted paths allowing reconfigurable resolution and spatial filtering. An energy-based image representation is also supported. These functionalities greatly simplify the operation of the subsequent digital processor implementing the high level logic of the vision algorithm. The resulting figures, 5.6mW@30fps, permit the integration of the smart image sensor with a wireless interface module (Imote2 from Memsic Corp.) for the development of vision-enabled WSN applications.

  10. Calibration of optical tweezers with positional detection in the back focal plane

    DEFF Research Database (Denmark)

    Tolic-Nørrelykke, S.F.; Schäffer, E.; Howard, J.;

    2006-01-01

    be moved instead, e. g., by acousto-optic deflectors. Near surfaces, this precision requires an improved formula for the hydrodynamical interaction between an infinite plane and a microsphere in nonconstant motion parallel to it. We give such a formula. (c) 2006 American Institute of Physics....

  11. An Infrared Focal Plane Array Camera System for Stereo-based Radiometric Imaging

    Science.gov (United States)

    1999-01-01

    Plane Array Calibrated System ( FPACS ) utilizes several features to help ensure radiometric accuracy. Some features help minimize unwanted radiation...possible, and beyond that, the FPACS design ensures that the operator is made aware when operating conditions may lead to radiometric inaccuracies. Primary...components of FPACS are illustrated in Fig. 1. Components are 1) Optics, 2) FPA/Dewar, 3) Camera Electronics, 4) Pan & Tilt platform, and 4) Windows

  12. Conversion electron spectroscopy at the FMA focal plane: Decay studies of proton-rich N {approximately} 82 nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nisius, D.; Janssens, R.V.F.; Ahmad, I. [and others

    1995-08-01

    The FMA has proven to be an ideal instrument for the detailed study of the decay of microsecond isomers behind the focal plane following mass selection. In reactions leading to the population of nuclei with isomeric lifetimes longer than their flight time through the device, decay gamma rays and conversion electrons can be detected in an environment free from the backgrounds of prompt radiation and delta electrons. This was a very successful technique to study proton (h{sub 11/2}){sup n} seniority isomers in nuclei with Z > 64 and N {approximately} 82. Since isomeric decay gamma rays are emitted isotropically, conversion electrons are essential for the assignment of multipolarities in these nuclei. Furthermore, the low-energy transitions that depopulate isomeric states are typically highly converted and can escape gamma-ray detection, but they can be identified by their conversion electrons.

  13. Focal-plane wavefront sensing for active optics in the VST based on an analytical optical aberration model

    Science.gov (United States)

    Holzlöhner, R.; Taubenberger, S.; Rakich, A. P.; Noethe, L.; Schipani, P.; Kuijken, K.

    2016-08-01

    We study a novel focal plane wavefront sensing and active optics control scheme at the VST on Cerro Paranal, an f/5.5 survey telescope with a 1x1 degree field of view and a 2.6m primary mirror. This scheme analyzes the elongation pattern of stellar PSFs across the full science image (256 Mpixels) and compares their second moments with an analytical model based on 5th-order geometrical optics. We consider 11 scalar degrees of freedom in mirror misalignments and deformations (M2 piston, tip/tilt and lateral displacement, detector tip/tilt, plus M1 figure astigmatism and trefoil). Using a numerical optimization method, we extract up to 4000 stars and complete the fitting process in under one minute. We demonstrate successful closed-loop active optics control based on maximum likelihood filtering.

  14. State of the art of AIM LWIR and VLWIR MCT 2D focal plane detector arrays for higher operating temperatures

    Science.gov (United States)

    Figgemeier, H.; Hanna, S.; Eich, D.; Mahlein, K.-M.; Fick, W.; Schirmacher, W.; Thöt, R.

    2016-05-01

    In this paper AIM presents its latest results on both n-on-p and p-on-n low dark current planar MCT photodiode technology LWIR and VLWIR two-dimensional focal plane detector arrays with a cut-off wavelength >11μm at 80K and a 640x512 pixel format at a 20μm pitch. Thermal dark currents significantly reduced as compared to `Tennant's Rule 07' at a yet good detection efficiency >60% as well as results from NETD and photo response performance characterization are presented. The demonstrated detector performance paces the way for a new generation of higher operating temperature LWIR MCT FPAs with a <30mK NETD up to a 110K detector operating temperature and with good operability.

  15. Snapshot linear-Stokes imaging spectropolarimeter using division-of-focal-plane polarimetry and integral field spectroscopy.

    Science.gov (United States)

    Mu, Tingkui; Pacheco, Shaun; Chen, Zeyu; Zhang, Chunmin; Liang, Rongguang

    2017-02-13

    In this paper, the design and experimental demonstration of a snapshot linear-Stokes imaging spectropolarimeter (SLSIS) is presented. The SLSIS, which is based on division-of-focal-plane polarimetry with four parallel linear polarization channels and integral field spectroscopy with numerous slit dispersive paths, has no moving parts and provides video-rate Stokes-vector hyperspectral datacubes. It does not need any scanning in the spectral, spatial or polarization dimension and offers significant advantages of rapid reconstruction without heavy computation during post-processing. The principle and the experimental setup of the SLSIS are described in detail. The image registration, Stokes spectral reconstruction and calibration procedures are included, and the system is validated using measurements of tungsten light and a static scene. The SLSIS's snapshot ability to resolve polarization spectral signatures is demonstrated using measurements of a dynamic scene.

  16. Development of Ultra-Low Noise, High Performance III-V Quantum Well Infrared Photodetectors (QWIPs) for Focal Plane Array Staring Image Sensor Systems

    Science.gov (United States)

    1993-08-01

    omem . 0o70,88 PUNK t~fq b iet fat tht ccle0l1oM of •.ea •as•fa" o0110 8 Itod =0* " 𔄂•1• 8 ao.. .1. nCfa OW totf for *Wct 811. 481JruftlC0 . Wo l...aperture sizes . Detailed results are depicted in Section 3.4. 1 5. Completed noise characterization on four different types of III-V QWIPs. From the...quantum well dopant density, biaxial strain strength, and structure parameters, the PSL-QWIPs can be used for 8-14 pm long-wavelength large size focal plane

  17. Focal plane array detectors with micro-bolometer structure and its application in IR and THz imaging

    Science.gov (United States)

    Wang, Jun; Mou, Wenchao; Gou, Jun; Jiang, Yadong

    2016-10-01

    Focal Plane Array (FPA) detector has characteristics of low cost, operating at room temperature, compatibility with the silicon CMOS technology, and high detecting performance, therefore it becomes a hot spot in infrared (IR) or terahertz (THz) detect field recently. However, the tradition structure of micro-bolometer has the conflict of the pixel size and thermal performance. In order to improve the detecting performance of small pixel size bolometer, high fill factor and low thermal conductance design should be considered. In IR detecting, double layers structure is an efficient method to improve the absorption of micro-bolometer and reduce thermal conductance. The three-dimension model of small size micro-bolometer was built in this article. The thermal and mechanical characters of those models were simulated and optimized, and finally the double layer structure micro-bolometer was fabricated with multifarious semiconductor recipes on the readout integrated chip wafer. For THz detecting, to improve the detecting performance, different dimension THz detectors based on micro-bridge structure were designed and fabricated to get optimizing micro-bolometer parameters from the test results of membrane deformation. A nanostructured titanium thin film absorber is integrated in the micro-bridge structure of the VOx micro-bolometer to enhance the absorption of THz radiation. Continuous-wave THz detection and imaging are demonstrated with a 2.52 THz far infrared CO2 laser and fabricated 320×240 vanadium oxide micro-bolometer focal plane array with optimized cell structure. With this detecting system, THz imaging of metal concealed in wiping cloth and envelope is demonstrated.

  18. Low-power focal-plane dynamic texture segmentation based on programmable image binning and diffusion hardware

    Science.gov (United States)

    Fernández-Berni, Jorge; Carmona-Galán, Ricardo

    2009-05-01

    Stand-alone applications of vision are severely constrained by their limited power budget. This is one of the main reasons why vision has not yet been widely incorporated into wireless sensor networks. For them, image processing should be suscribed to the sensor node in order to reduce network traffic and its associated power consumption. In this scenario, operating the conventional acquisition-digitization-processing chain is unfeasible under tight power limitations. A bio-inspired scheme can be followed to meet the timing requirements while maintaining a low power consumption. In our approach, part of the low-level image processing is conveyed to the focal-plane thus speeding up system operation. Moreover, if a moderate accuracy is permissible, signal processing is realized in the analog domain, resulting in a highly efficient implementation. In this paper we propose a circuit to realize dynamic texture segmentation based on focal-plane spatial bandpass filtering of image subdivisions. By the appropriate binning, we introduce some constrains into the spatial extent of the targeted texture. By running time-controlled linear diffusion within each bin, a specific band of spatial frequencies can be highlighted. Measuring the average energy of the components in that band at each image bin the presence of a targeted texture can be detected and quantified. The resulting low-resolution representation of the scene can be then employed to track the texture along an image flow. An application specific chip, based on this analysis, is being developed for natural spaces monitoring by means of a network of low-power vision systems.

  19. High-contrast single-particle tracking by selective focal plane illumination microscopy.

    Science.gov (United States)

    Ritter, Jörg G; Veith, Roman; Siebrasse, Jan-Peter; Kubitscheck, Ulrich

    2008-05-12

    Wide-field single molecule microscopy is a versatile tool for analyzing dynamics and molecular interactions in biological systems. In extended three-dimensional systems, however, the method suffers from intrinsic out-of-focus fluorescence. We constructed a high-resolution selective plane illumination microscope (SPIM) to efficiently solve this problem. The instrument is an optical sectioning microscope featuring the high speed and high sensitivity of a video microscope. We present theoretical calculations and quantitative measurements of the illumination light sheet thickness yielding 1.7 microm (FWHM) at 543 nm, 2.0 microm at 633 nm, and a FWHM of the axial point spread function of 1.13 microm. A direct comparison of selective plane and epi-illumination of model samples with intrinsic background fluorescence illustrated the clear advantage of SPIM for such samples. Single fluorescent quantum dots in aqueous solution are readily visualized and tracked proving the suitability of our setup for the study of fast and dynamic processes in spatially extended biological specimens.

  20. A simulation study on the focal plane detector of the LAUE project

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, M., E-mail: mkhalil@in2p3.fr [APC Laboratory, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France); Department of Physics and Earth Sciences, University of Ferrara, Via Saragat, 1, 44100 Ferrara (Italy); Frontera, F. [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat, 1, 44100 Ferrara (Italy); INAF/IASF-Bologna, Via P. Gobetti 101, Bologna (Italy); Caroli, E. [INAF/IASF-Bologna, Via P. Gobetti 101, Bologna (Italy); Virgilli, E.; Valsan, V. [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat, 1, 44100 Ferrara (Italy)

    2015-06-21

    The LAUE project, supported by the Italian Space Agency (ASI), is devoted to the development of a long focal length (even 20 m or longer) Laue lens for gamma ray astronomy between 80 and 600 keV. These lenses take advantage of Bragg diffraction to focus radiation onto a small spot drastically improving the signal to noise ratio as well as reducing the required size of the detector significantly. In this paper we present a Monte-Carlo simulation study with MEGALIB to optimize, for space applications, the detector size to achieve high detection efficiency, and to optimize the position resolution of the detector to reconstruct the Point Spread Function of the lens considered for the LAUE project. Then we will show simulations, using the SILVACO semiconductor simulation toolkit, on the optimized detector to estimate its capacitance per channel and depletion voltage. In all of the simulations, two materials were compared; a low density material (Silicon) and a high density material (Germanium). - Highlights: • The quantized Hall plateaus and Shubnikov de Haas oscillations in transition metal doped topological insulators are observed. • The evidence of a two-dimensional/layered transport of the bulk electrons is reported. • An obvious ferromagnetism in doped topological insulators is observed. • Care should be taken to pindown the transport of the topological SS in topological insulators.

  1. On-sky demonstration of low-order wavefront sensing and control with focal plane phase mask coronagraphs

    CERN Document Server

    Singh, Garima; Guyon, Olivier; Baudoz, Pierre; Jovanovic, Nemanja; Martinache, Frantz; Kudo, Tomoyuki; Serabyn, Eugene; Kuhn, Jonas

    2015-01-01

    The ability to characterize exoplanets by spectroscopy of their atmospheres requires direct imaging techniques to isolate planet signal from the bright stellar glare. One of the limitations with the direct detection of exoplanets, either with ground- or space-based coronagraphs, is pointing errors and other low-order wavefront aberrations. The coronagraphic detection sensitivity at the diffraction limit therefore depends on how well low-order aberrations upstream of the focal plane mask are corrected. To prevent starlight leakage at the inner working angle of a phase mask coronagraph, we have introduced a Lyot-based low-order wavefront sensor (LLOWFS), which senses aberrations using the rejected starlight diffracted at the Lyot plane. In this paper, we present the implementation, testing and results of LLOWFS on the Subaru Coronagraphic Extreme Adaptive Optics system (SCExAO) at the Subaru Telescope. We have controlled thirty-five Zernike modes of a H-band vector vortex coronagraph in the laboratory and ten Z...

  2. RMT focal plane sensitivity to seismic network geometry and faulting style

    Science.gov (United States)

    Johnson, Kendra L.; Hayes, Gavin P.; Herrmann, Robert B.; Benz, Harley M.; McNamara, Dan E.; Bergman, Eric

    2016-07-01

    Modern tectonic studies often use regional moment tensors (RMTs) to interpret the seismotectonic framework of an earthquake or earthquake sequence; however, despite extensive use, little existing work addresses RMT parameter uncertainty. Here, we quantify how network geometry and faulting style affect RMT sensitivity. We examine how data-model fits change with fault plane geometry (strike and dip) for varying station configurations. We calculate the relative data fit for incrementally varying geometries about a best-fitting solution, applying our workflow to real and synthetic seismograms for both real and hypothetical station distributions and earthquakes. Initially, we conduct purely observational tests, computing RMTs from synthetic seismograms for hypothetical earthquakes and a series of well-behaved network geometries. We then incorporate real data and station distributions from the International Maule Aftershock Deployment (IMAD), which recorded aftershocks of the 2010 MW 8.8 Maule earthquake, and a set of regional stations capturing the ongoing earthquake sequence in Oklahoma and southern Kansas. We consider RMTs computed under three scenarios: (1) real seismic records selected for high data quality; (2) synthetic seismic records with noise computed for the observed source-station pairings and (3) synthetic seismic records with noise computed for all possible station-source pairings. To assess RMT sensitivity for each test, we observe the `fit falloff', which portrays how relative fit changes when strike or dip varies incrementally; we then derive the ranges of acceptable strikes and dips by identifying the span of solutions with relative fits larger than 90 per cent of the best fit. For the azimuthally incomplete IMAD network, Scenario 3 best constrains fault geometry, with average ranges of 45° and 31° for strike and dip, respectively. In Oklahoma, Scenario 3 best constrains fault dip with an average range of 46°; however, strike is best constrained by

  3. Megapixel mercury cadmium telluride focal plane arrays for infrared imaging out to 12 microns Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the fabrication of large format, long wave infrared (LWIR) mercury cadmium telluride (HgCdTe or MCT) detector arrays where the cutoff wavelength is...

  4. Hyperspectral Longwave Infrared Focal Plane Array and Camera Based on Quantum Well Infrared Photodetectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a hyperspectral camera imaging in a large number of sharp hyperspectral bands in the thermal infrared. The camera is particularly suitable for...

  5. Lead Chalcogenide on Silicon Infrared Focal Plane Arrays for Thermal Imaging(Review Paper

    Directory of Open Access Journals (Sweden)

    Hans Zogg

    2001-01-01

    Full Text Available "Narrow gap IV-VI [lead chalcogenides like Pbl-xSnxSe and PbTe] layers grown epitaxially on silicon( III substrates by molecular beam epitaxy exhibit high quality despite the large lattice and thermal expansion mismatch. A CaF2 buffer layer is employed for compatibility. Due to easy glide of misfit dislocations in the IV- VI layers, thei1rtal strains relax even at cryogenic. temperatures and after many temperature cyclings. The high permittivities of the IV- VI layers effectively shield the electric fields from charged defects. Higher quality devices are obtained from lower quality material, at variance to narrow gap 11- VI and 111- V compounds. Material characterisation and sensor array properties have been reviewed. Schottky barrier or p-n+ sensor arrays have been delineated using standard photolithography. At low temperatures, the sensitivities are limited by defects, mainly dislocations, and the device performance is predicted by the dislocation density. At higher temperatures, the ultimate theoretical sensitivity is obtained with Schottky barrier devices despite large mismatch and with only 3 µm thickness of the layers. First chara'cterisations of a 96 x 128 array on a silicon substrate containing the read-out circuits show that the concept is functional and gives high yield.

  6. A large aperture balloon-borne telescope for a submillimeter wavelength survey of the galactic plane

    Science.gov (United States)

    Silverberg, R. F.; Hauser, M. G.; Walser, D. W.; Flanick, A.; Silver, A. D.; Smith, J.; Gezari, D. Y.; Kelsall, T.; Cheung, L. H.; Skillman, T. L., Jr.

    1983-01-01

    A balloon-borne, 1.2 meter Cassegrain telescope with a servo-controlled chopping secondary mirror has been developed and used to survey the Galactic Plane at submillimeter wavelengths. The telescope pointing system uses a gyroscope as the primary stabilization reference and makes use of microprocessors for pointing control, on-board data collection, and telemetry formatting. A description of the telescope, multi-channel liquid-helium-cooled focal plane and the aspect and orientation subsystems are presented.

  7. The self-coherent camera as a focal plane phasing sensor

    Science.gov (United States)

    Janin-Potiron, P.; Martinez, P.; Baudoz, P.; Carbillet, M.

    2016-09-01

    Exoplanets imaging requires very high angular resolution that will be reached with the forthcoming generation of extremely large telescopes. In order to achieve the high performance required for the astronomical science programs, the errors due to segment misalignment must be reduced to tens of nm. Therefore the development of new co-phasing techniques is of critical importance for ground-based telescopes, and to a large extent for future space-based missions. We propose a new co-phasing method directly exploiting the scientific image delivered by the self coherent camera (SCC) by adequately combining segment misalignment estimators (piston and tip/tilt) and image processing. The extension of the SCC concept towards a co-phasing sensor is presented and its parameter space and performance for phasing a segmented telescope are studied by means of intensive numerical simulations. The self-coherent camera phasing sensor (SCC-PS) is shown to be capable of estimating accurately and simultaneously piston and tip/tilt misalignments and to correct them in close-loop operation in a few iterations. The final residual RMS values over the pupil obtained with the SCC-PS are compared to similar simulations of another co-phasing sensor and we show that the SCC-PS gives the same or even better results by requiring less iterations. By contrast to several phasing sensor concepts the SCC-PS does not require any a priori knowledge on the signal at the segment boundaries, or a dedicated optical path. The SCC-PS is a non-invasive concept that works directly on the scientific image of the instrument, either in a coronagrahic or a non-coronagraphic observing mode. The primary results obtained in this study are very promising and demonstrate that the SCC-PS is a serious candidate for segment co-phasing at the instrument level or at the telescope level for both ground- and space-based applications.

  8. High-performance visible/UV CCD focal plane technology for spacebased applications

    Science.gov (United States)

    Burke, B. E.; Mountain, R. W.; Gregory, J. A.; Huang, J. C. M.; Cooper, M. J.; Savoye, E. D.; Kosicki, B. B.

    1993-01-01

    We describe recent technology developments aimed at large CCD imagers for space based applications in the visible and UV. Some of the principal areas of effort include work on reducing device degradation in the natural space-radiation environment, improvements in quantum efficiency in the visible and UV, and larger-device formats. One of the most serious hazards for space based CCD's operating at low signal levels is the displacement damage resulting from bombardment by energetic protons. Such damage degrades charge-transfer efficiency and increases dark current. We have achieved improved hardness to proton-induced displacement damage by selective ion implants into the CCD channel and by reduced temperature of operation. To attain high quantum efficiency across the visible and UV we have developed a technology for back-illuminated CCD's. With suitable antireflection (AR) coatings such devices have quantum efficiencies near 90 percent in the 500-700-nm band. In the UV band from 200 to 400 nm, where it is difficult to find coatings that are sufficiently transparent and can provide good matching to the high refractive index of silicon, we have been able to substantially increase the quantum efficiency using a thin film of HfO2 as an AR coating. These technology efforts were applied to a 420 x 420-pixel frame-transfer imager, and future work will be extended to a 1024 x 1024-pixel device now under development.

  9. High-performance visible/UV CCD focal plane technology for spacebased applications

    Science.gov (United States)

    Burke, B. E.; Mountain, R. W.; Gregory, J. A.; Huang, J. C. M.; Cooper, M. J.; Savoye, E. D.; Kosicki, B. B.

    1993-01-01

    We describe recent technology developments aimed at large CCD imagers for space based applications in the visible and UV. Some of the principal areas of effort include work on reducing device degradation in the natural space-radiation environment, improvements in quantum efficiency in the visible and UV, and larger-device formats. One of the most serious hazards for space based CCD's operating at low signal levels is the displacement damage resulting from bombardment by energetic protons. Such damage degrades charge-transfer efficiency and increases dark current. We have achieved improved hardness to proton-induced displacement damage by selective ion implants into the CCD channel and by reduced temperature of operation. To attain high quantum efficiency across the visible and UV we have developed a technology for back-illuminated CCD's. With suitable antireflection (AR) coatings such devices have quantum efficiencies near 90 percent in the 500-700-nm band. In the UV band from 200 to 400 nm, where it is difficult to find coatings that are sufficiently transparent and can provide good matching to the high refractive index of silicon, we have been able to substantially increase the quantum efficiency using a thin film of HfO2 as an AR coating. These technology efforts were applied to a 420 x 420-pixel frame-transfer imager, and future work will be extended to a 1024 x 1024-pixel device now under development.

  10. The imaging properties of the Gas Pixel Detector as a focal plane polarimeter

    CERN Document Server

    Fabiani, S; Del Monte, E; Muleri, F; Soffitta, P; Rubini, A; Bellazzini, R; Brez, A; de Ruvo, L; Minuti, M; Pinchera, M; Sgrò, C; Spandre, G; Spiga, D; Tagliaferri, G; Pareschi, G; Basso, S; Citterio, O; Burwitz, V; Burkert, W; Menz, B; Hartner, G

    2014-01-01

    X-rays are particularly suited to probe the physics of extreme objects. However, despite the enormous improvements of X-ray Astronomy in imaging, spectroscopy and timing, polarimetry remains largely unexplored. We propose the photoelectric polarimeter Gas Pixel Detector (GPD) as an instrument candidate to fill the gap of more than thirty years of lack of measurements. The GPD, in the focus of a telescope, will increase the sensitivity of orders of magnitude. Moreover, since it can measure the energy, the position, the arrival time and the polarization angle of every single photon, allows to perform polarimetry of subsets of data singled out from the spectrum, the light curve or the image of source. The GPD has an intrinsic very fine imaging capability and in this work we report on the calibration campaign carried out in 2012 at the PANTER X-ray test facility of the Max-Planck-Institut f\\"ur extraterrestrische Physik of Garching (Germany) in which, for the first time, we coupled it to a JET-X optics module wit...

  11. InGaAs focal plane array developments at III-V Lab

    Science.gov (United States)

    Rouvié, Anne; Reverchon, Jean-Luc; Huet, Odile; Djedidi, Anis; Robo, Jean-Alexandre; Truffer, Jean-Patrick; Bria, Toufiq; Pires, Mauricio; Decobert, Jean; Costard, Eric

    2012-06-01

    SWIR detection band benefits from natural (sun, night glow, thermal radiation) or artificial (eye safe lasers) photons sources combined to low atmospheric absorption and specific contrast compared to visible wavelengths. It gives the opportunity to address a large spectrum of applications such as defense and security (night vision, active imaging), space (earth observation), transport (automotive safety) or industry (non destructive process control). InGaAs material appears as a good candidate to satisfy SWIR detection needs. The lattice matching with InP constitutes a double advantage to this material: attractive production capacity and uncooled operation thanks to low dark current level induced by high quality material. For few years, III-VLab has been studying InGaAs imagery, gathering expertise in InGaAs material growth and imaging technology respectively from Alcatel-Lucent and Thales, its two mother companies. This work has lead to put quickly on the market a 320x256 InGaAs module, exhibiting high performances in terms of dark current, uniformity and quantum efficiency. In this paper, we present the last developments achieved in our laboratory, mainly focused on increasing the pixels number to VGA format associated to pixel pitch decrease (15μm) and broadening detection spectrum toward visible wavelengths. Depending on targeted applications, different Read Out Integrated Circuits (ROIC) have been used. Low noise ROIC have been developed by CEA LETI to fit the requirements of low light level imaging whereas logarithmic ROIC designed by NIT allows high dynamic imaging adapted for automotive safety.

  12. Guided filter and adaptive learning rate based non-uniformity correction algorithm for infrared focal plane array

    Science.gov (United States)

    Sheng-Hui, Rong; Hui-Xin, Zhou; Han-Lin, Qin; Rui, Lai; Kun, Qian

    2016-05-01

    Imaging non-uniformity of infrared focal plane array (IRFPA) behaves as fixed-pattern noise superimposed on the image, which affects the imaging quality of infrared system seriously. In scene-based non-uniformity correction methods, the drawbacks of ghosting artifacts and image blurring affect the sensitivity of the IRFPA imaging system seriously and decrease the image quality visibly. This paper proposes an improved neural network non-uniformity correction method with adaptive learning rate. On the one hand, using guided filter, the proposed algorithm decreases the effect of ghosting artifacts. On the other hand, due to the inappropriate learning rate is the main reason of image blurring, the proposed algorithm utilizes an adaptive learning rate with a temporal domain factor to eliminate the effect of image blurring. In short, the proposed algorithm combines the merits of the guided filter and the adaptive learning rate. Several real and simulated infrared image sequences are utilized to verify the performance of the proposed algorithm. The experiment results indicate that the proposed algorithm can not only reduce the non-uniformity with less ghosting artifacts but also overcome the problems of image blurring in static areas.

  13. Digital readout integrated circuit (DROIC) implementing time delay and integration (TDI) for scanning type infrared focal plane arrays (IRFPAs)

    Science.gov (United States)

    Ceylan, Omer; Shafique, Atia; Burak, Abdurrahman; Caliskan, Can; Yazici, Melik; Abbasi, Shahbaz; Galioglu, Arman; Kayahan, Huseyin; Gurbuz, Yasar

    2016-11-01

    This paper presents a digital readout integrated circuit (DROIC) implementing time delay and integration (TDI) for scanning type infrared focal plane arrays (IRFPAs) with a charge handling capacity of 44.8 Me- while achieving quantization noise of 198 e- and power consumption of 14.35 mW. Conventional pulse frequency modulation (PFM) method is supported by a single slope ramp ADC technique to have a very low quantization noise together with a low power consumption. The proposed digital TDI ROIC converts the photocurrent into digital domain in two phases; in the first phase, most significant bits (MSBs) are generated by the conventional PFM technique in the charge domain, while in the second phase least significant bits (LSBs) are generated by a single slope ramp ADC in the time domain. A 90 × 8 prototype has been fabricated and verified, showing a significantly improved signal-to-noise ratio (SNR) of 51 dB for low illumination levels (280,000 collected electrons), which is attributed to the TDI implementation method and very low quantization noise due to the single slope ADC implemented for LSBs. Proposed digital TDI ROIC proves the benefit of digital readouts for scanning arrays enabling smaller pixel pitches, better SNR for the low illumination levels and lower power consumption compared to analog TDI readouts for scanning arrays.

  14. Identification and Quantification of Microplastics in Wastewater Using Focal Plane Array-Based Reflectance Micro-FT-IR Imaging.

    Science.gov (United States)

    Tagg, Alexander S; Sapp, Melanie; Harrison, Jesse P; Ojeda, Jesús J

    2015-06-16

    Microplastics (microplastics in these matrices has not been investigated. Although efficient methods for the analysis of microplastics in sediment samples and marine organisms have been published, no methods have been developed for detecting these pollutants within organic-rich wastewater samples. In addition, there is no standardized method for analyzing microplastics isolated from environmental samples. In many cases, part of the identification protocol relies on visual selection before analysis, which is open to bias. In order to address this, a new method for the analysis of microplastics in wastewater was developed. A pretreatment step using 30% hydrogen peroxide (H2O2) was employed to remove biogenic material, and focal plane array (FPA)-based reflectance micro-Fourier-transform (FT-IR) imaging was shown to successfully image and identify different microplastic types (polyethylene, polypropylene, nylon-6, polyvinyl chloride, polystyrene). Microplastic-spiked wastewater samples were used to validate the methodology, resulting in a robust protocol which was nonselective and reproducible (the overall success identification rate was 98.33%). The use of FPA-based micro-FT-IR spectroscopy also provides a considerable reduction in analysis time compared with previous methods, since samples that could take several days to be mapped using a single-element detector can now be imaged in less than 9 h (circular filter with a diameter of 47 mm). This method for identifying and quantifying microplastics in wastewater is likely to provide an essential tool for further research into the pathways by which microplastics enter the environment.

  15. Development of High-Performance eSWIR HgCdTe-Based Focal-Plane Arrays on Silicon Substrates

    Science.gov (United States)

    Park, J. H.; Pepping, J.; Mukhortova, A.; Ketharanathan, S.; Kodama, R.; Zhao, J.; Hansel, D.; Velicu, S.; Aqariden, F.

    2016-09-01

    We report the development of high-performance and low-cost extended short-wavelength infrared (eSWIR) focal-plane arrays (FPAs) fabricated from molecular beam epitaxial (MBE)-grown HgCdTe on Si-based substrates. High-quality n-type eSWIR HgCdTe (cutoff wavelength ˜2.68 μm at 77 K, electron carrier concentration 5.82 × 1015 cm-3) layers were grown on CdTe/Si substrates by MBE. High degrees of uniformity in composition and thickness were demonstrated over three-inch areas, and low surface defect densities (voids 9.56 × 101 cm-2, micro-defects 1.67 × 103 cm-2) were measured. This material was used to fabricate 320 × 256 format, 30 μm pitch FPAs with a planar device architecture using arsenic implantation to achieve p-type doping. The dark current density of test devices showed good uniformity between 190 K and room temperature, and high-quality eSWIR imaging from hybridized FPAs was obtained with a median dark current density of 2.63 × 10-7 A/cm2 at 193 K with a standard deviation of 1.67 × 10-7 A/cm2.

  16. Design, fabrication and testing of 17um pitch 640x480 uncooled infrared focal plane array detector

    Science.gov (United States)

    Jiang, Lijun; Liu, Haitao; Chi, Jiguang; Qian, Liangshan; Pan, Feng; Liu, Xiang

    2015-10-01

    Uncooled infrared focal plane array (UIRFPA) detectors are widely used in industrial thermography cameras, night vision goggles, thermal weapon sights, as well as automotive night vision systems. To meet the market requirement for smaller pixel pitch and higher resolution, we have developed a 17um pitch 640x480 UIRFPA detector. The detector is based on amorphous silicon (a-Si) microbolometer technology, the readout integrated circuit (ROIC) is designed and manufactured with 0.35um standard CMOS technology on 8 inch wafer, the microbolometer is fabricated monolithically on the ROIC using an unique surface micromachining process developed inside the company, the fabricated detector is vacuum packaged with hermetic metal package and tested. In this paper we present the design, fabrication and testing of the 17um 640x480 detector. The design trade-off of the detector ROIC and pixel micro-bridge structure will be discussed, by comparison the calculation and simulation to the testing results. The novel surface micromachining process using silicon sacrificial layer will be presented, which is more compatible with the CMOS process than the traditional process with polyimide sacrificial layer, and resulted in good processing stability and high fabrication yield. The performance of the detector is tested, with temperature equivalent temperature difference (NETD) less than 60mK at F/1 aperture, operability better than 99.5%. The results demonstrate that the detector can meet the requirements of most thermography and night vision applications.

  17. A 250 frames-per-second 640 by 480 pixel division-of-focal-plane polarimeter for the visible spectrum

    Science.gov (United States)

    York, Timothy; Marinov, Radoslav; Gruev, Viktor

    2014-05-01

    The most common method of polarimetery involves imaging a scene through a polarization analyzer at multiple configurations. Switching among these configurations requires capturing multiple images of the scene, limiting the ability to capture real-time polarization data due to multiple scene sampling and motion artifacts. Advances in nanofabrication technology have allowed direct integration of polarization analyzers onto the sensor, enabling the capture of multiple analyzer intensities from a single frame. Using this technique, we have fabricated a high frame rate, VGA resolution, division of focal plane polarization imager for the visible spectrum. The imaging sensor is realized by monolithic integration of aluminum nanowires with an array of CCD imaging elements. The pixelated nanowire polarization filters are at four different orientations offset by 45° This allows for recording of the first three Stokes parameters at every super pixel, and subsequently the degree of linear polarization and angle of polarization are computed at 250 frames per second at full VGA resolution and over 1000 when limited to a subsection of the array. The imaging sensor also employs a per pixel calibration scheme which mitigates the variations in the aluminum nanowire sizes. We present an optical characterization of the sensor, and then utilize the increased frame rate to capture high speed polarization images of pieces of polycarbonate plastic placed under stress. The high frame rate allows us to recover strain information that regular rate sensors cannot.

  18. A per-pixel Log2ADC for high dynamic range, 1000FPS digital focal plane arrays (DFPA)

    Science.gov (United States)

    Petilli, Eugene

    2016-09-01

    Intrinsix has developed a Digital Focal Plane Array (DFPA) architecture based on a novel piecewise linear Log2 ADC (LADC) with "lossless" analog compression which enables ultra-high dynamic range ROICs that use less power than other extended dynamic range technologies. The LADC provides dynamic range of 126dB with a constant 75dB SNR over the entire frame. The companding 13bit mantissa, 3bit radix per pixel LADCs compress the 21bit signals into efficient 16 bit data words. The Read Out IC (ROIC) is compatible with most IR and LWIR detectors including two-color SLS (photodiode) and uBolometers. The DFPA architecture leverages two (staggered frame prime and redundant) MIPI CSI-3 interfaces to achieve full HD DFPA at 1000 frames/sec; an equivalent uncompressed data rate of 100Gb/sec. The LADC uses direct injection into a moderate sized integrating capacitor and several comparators create a stream of multi-bit data values. These values are accumulated in an SRAM based log2ALU and the radix of the ALU is combined with the data to generate a feedback current to the integrating capacitor, closing the delta loop. The integration time and a single pole low pass IIR filter are configurable using control signals to the log2ALU. The feedback current is at least partially generated using PWM for high linearity.

  19. The design and application of large area intensive lens array focal spots measurement system

    Science.gov (United States)

    Chen, Bingzhen; Yao, Shun; Yang, Guanghui; Dai, Mingchong; Wang, Zhiyong

    2014-12-01

    Concentrating Photovoltaic (CPV) modules are getting thinner and using smaller cells now days. Correspondingly, large area intensive lens arrays with smaller unit dimension and shorter focal length are wanted. However, the size and power center of lens array focal spots usually differ from the design value and are hard to measure, especially under large area situation. It is because the machining error and deformation of material of the lens array are hard to simulate in the optical design process. Thus the alignment error between solar cells and focal spots in the module assembly process will be hard to control. Under this kind of situation, the efficiency of CPV module with thinner body and smaller cells is much lower than expected. In this paper, a design of large area lens array focal spots automatic measurement system is presented, as well as its prototype application results. In this system, a four-channel parallel light path and its corresponding image capture and process modules are designed. These modules can simulate focal spots under sunlight and have the spots image captured and processed using charge coupled devices and certain gray level algorithm. Thus the important information of focal spots such as spot size and location will be exported. Motion control module based on grating scale signal and interval measurement method are also employed in this system in order to get test results with high speed and high precision on large area lens array no less than 1m×0.8m. The repeatability of the system prototype measurement is +/-10μm with a velocity of 90 spot/min. Compared to the original module assembled using coordinates from optical design, modules assembled using data exported from the prototype is 18% higher in output power, reaching a conversion efficiency of over 31%. This system and its design can be used in the focal spot measurement of planoconvex lens array and Fresnel lens array, as well as other kinds of large area lens array application

  20. Low dark current MCT-based focal plane detector arrays for the LWIR and VLWIR developed at AIM

    Science.gov (United States)

    Gassmann, Kai Uwe; Eich, Detlef; Fick, Wolfgang; Figgemeier, Heinrich; Hanna, Stefan; Thöt, Richard

    2015-10-01

    For nearly 40 years AIM develops, manufactures and delivers photo-voltaic and photo-conductive infrared sensors and associated cryogenic coolers which are mainly used for military applications like pilotage, weapon sights, UAVs or vehicle platforms. In 2005 AIM started to provide the competences also for space applications like IR detector units for the SLSTR instrument on board of the Sentinel 3 satellite, the hyperspectral SWIR Imager for EnMAP or pushbroom detectors for high resolution Earth observation satellites. Meanwhile AIM delivered more than 25 Flight Models for several customers. The first European pulse-tube cooler ever operating on-board of a satellite is made by AIM. AIM homes the required infrared core capabilities such as design and manufacturing of focal plane assemblies, detector housing technologies, development and manufacturing of cryocoolers and also data processing for thermal IR cameras under one roof which enables high flexibility to react to customer needs and assures economical solutions. Cryogenically cooled Hg(1-x)CdxTe (MCT) quantum detectors are unequalled for applications requiring high imaging as well as high radiometric performance in the infrared spectral range. Compared with other technologies, they provide several advantages, such as the highest quantum efficiency, lower power dissipation compared to photoconductive devices and fast response times, hence outperforming micro-bolometer arrays. However, achieving an excellent MCT detector performance at long (LWIR) and very long (VLWIR) infrared wavelengths is challenging due to the exponential increase in the thermally generated photodiode dark current with increasing cut-off wavelength and / or operating temperature. Dark current is a critical design driver, especially for LWIR / VLWIR multi-spectral imagers with moderate signal levels or hyper-spectral Fourier spectrometers operating deep into the VLWIR spectral region. Consequently, low dark current (LDC) technologies are the

  1. A readout integrated circuit based on DBI-CTIA and cyclic ADC for MEMS-array-based focal plane

    Science.gov (United States)

    Miao, Liu; Dong, Wu; Zheyao, Wang

    2016-11-01

    A readout integrated circuit (ROIC) for a MEMS (microelectromechanical system)-array-based focal plane (MAFP) intended for imaging applications is presented. The ROIC incorporates current sources for diode detectors, scanners, timing sequence controllers, differential buffered injection-capacitive trans-impedance amplifier (DBI-CTIA) and 10-bit cyclic ADCs, and is integrated with MAFP using 3-D integration technology. A small-signal equivalent model is built to include thermal detectors into circuit simulations. The biasing current is optimized in terms of signal-to-noise ratio and power consumption. Layout design is tailored to fulfill the requirements of 3-D integration and to adapt to the size of MAFP elements, with not all but only the 2 bottom metal layers to complete nearly all the interconnections in DBI-CTIA and ADC in a 40 μm wide column. Experimental chips are designed and fabricated in a 0.35 μm CMOS mixed signal process, and verified in a code density test of which the results indicate a (0.29/-0.31) LSB differential nonlinearity (DNL) and a (0.61/-0.45) LSB integral nonlinearity (INL). Spectrum analysis shows that the effective number of bits (ENOB) is 9.09. The ROIC consumes 248 mW of power at most if not to cut off quiescent current paths when not needed. Project supported by by National Natural Science Foundation of China (No. 61271130), the Beijing Municipal Science and Tech Project (No. D13110100290000), the Tsinghua University Initiative Scientific Research Program (No. 20131089225), and the Shenzhen Science and Technology Development Fund (No. CXZZ20130322170740736).

  2. Colloidal quantum dot Vis-SWIR imaging: demonstration of a focal plane array and camera prototype (Presentation Recording)

    Science.gov (United States)

    Klem, Ethan J. D.; Gregory, Christopher W.; Temple, Dorota S.; Lewis, Jay S.

    2015-08-01

    RTI has developed a photodiode technology based on solution-processed PbS colloidal quantum dots (CQD). These devices are capable of providing low-cost, high performance detection across the Vis-SWIR spectral range. At the core of this technology is a heterojunction diode structure fabricated using techniques well suited to wafer-scale fabrication, such as spin coating and thermal evaporation. This enables RTI's CQD diodes to be processed at room temperature directly on top of read-out integrated circuits (ROIC), without the need for the hybridization step required by traditional SWIR detectors. Additionally, the CQD diodes can be fabricated on ROICs designed for other detector material systems, effectively allowing rapid prototype demonstrations of CQD focal plane arrays at low cost and on a wide range of pixel pitches and array sizes. We will show the results of fabricating CQD arrays directly on top of commercially available ROICs. Specifically, the ROICs are a 640 x 512 pixel format with 15 µm pitch, originally developed for InGaAs detectors. We will show that minor modifications to the surface of these ROICs make them suitable for use with our CQD detectors. Once completed, these FPAs are then assembled into a demonstration camera and their imaging performance is evaluated. In addition, we will discuss recent advances in device architecture and processing resulting in devices with room temperature dark currents of 2-5 nA/cm^2 and sensitivity from 350 nm to 1.7 μm. This combination of high performance, dramatic cost reduction, and multi-band sensitivity is ideally suited to expand the use of SWIR imaging in current applications, as well as to address applications which require a multispectral sensitivity not met by existing technologies.

  3. Uncooled SWIR InGaAs/GaAsSb type-II quantum well focal plane array

    Science.gov (United States)

    Inada, H.; Miura, K.; Mori, H.; Nagai, Y.; Iguchi, Y.; Kawamura, Y.

    2010-04-01

    Low dark current photodiodes (PDs) in the short wavelength infrared (SWIR) upto 2.5μm region, are expected for many applications. HgCdTe (MCT) is predominantly used for infrared imaging applications. However, because of high dark current, MCT device requires a refrigerator such as stirling cooler, which increases power consumption, size and cost of the sensing system. Recently, InGaAs/GaAsSb type II quantum well structures were considered as attractive material system for realizing low dark current PDs owing to lattice-matching to InP substrate. Planar type PIN-PDs were successfully fabricated. The absorption layer with 250 pair-InGaAs(5nm)/GaAsSb(5nm) quantum well structures was grown on S-doped (100) InP substrates by solid source molecular beam epitaxy method. InP and InGaAs were used for cap layer and buffer layer, respectively. The p-n junctions were formed in the absorption layer by the selective diffusion of zinc. Diameter of light-receiving region was 140μm. Low dark current was obtained by improving GaAsSb crystalline quality. Dark current density was 0.92mA/cm2 which was smaller than that of a conventional MCT. Based on the same process as the discrete device, a 320x256 planar type focal plane array was also fabricated. Each PD has 15μm diameter and 30μm pitch and it was bonded to read-out IC by using indium bump flip chip process. Finally, we have successfully demonstrated the 320 x256 SWIR image at room temperature. This result means that planer type PD array with the type II InGaAs/GaAsSb quantum well structure is a promising candidate for uncooled applications.

  4. Recent development of SWIR focal plane array with InGaAs/GaAsSb type-II quantum wells

    Science.gov (United States)

    Inada, Hiroshi; Machinaga, Kenichi; Balasekaran, Sundararajan; Miura, Kouhei; Kawahara, Takahiko; Migita, Masaki; Akita, Katsushi; Iguchi, Yasuhiro

    2016-05-01

    HgCdTe (MCT) is predominantly used for infrared imaging applications even in SWIR region. However, MCT is expensive and contains environmentally hazardous substances. Therefore, its application has been restricted mainly military and scientific use and was not spread to commercial use. InGaAs/GaAsSb type-II quantum well structures are considered as an attractive material for realizing low dark current PDs owing to lattice-matching to InP substrate. Moreover, III-V compound material systems are suitable for commercial use. In this report, we describe successful operation of focal plane array (FPA) with InGaAs/GaAsSb quantum wells and mention improvement of optical characteristics. Planar type pin-PDs with 250-pairs InGaAs(5nm)/GaAsSb(5nm) quantum well absorption layer were fabricated. The p-n junction was formed in the absorption layer by the selective diffusion of zinc. Electrical and optical characteristics of FPA or pin-PDs were investigated. Dark current of 1μA/cm2 at 210K, which showed good uniformity and led to good S/N ratio in SWIR region, was obtained. Further, we could successfully reduce of stray light in the cavity of FPA with epoxy resin. As a result, the clear image was taken with 320x256 format and 7% contrast improvement was achieved. Reliability test of 10,000 heat cycles was carried out. No degradations were found in FPA characteristics of the epoxy coated sample. This result means FPA using InGaAs/GaAsSb type-II quantum wells is a promising candidate for commercial applications.

  5. Focused, phased-array plane piston and spherically-shaped concave piston transducers: comparison for the same aperture and focal point.

    Science.gov (United States)

    Warriner, Renée K; Cobbold, Richard S C

    2012-04-01

    It has sometimes been assumed that the phased-array plane piston transducer and the spherically-shaped concave piston transducer are equivalent structures when both have the same aperture and focal point. This assumption has not been previously examined, nor has an expression for the on-axis impulse response of the focused, phased-array plane piston transducer been derived. It is shown in this paper how such an expression can be obtained. Comparisons of the impulse response for both structures show similarities, as well as some differences that could be significant as the observation point approaches the focal point. Comparisons are also performed for wide-band pulses close to the focus as well as for sinusoidal excitation. A physical explanation for the cause of the impulse response discrepancy is shown to be due to the nature of the piston focusing delay and its effect on the Rayleigh integral.

  6. MultiFocus Polarization Microscope (MF-PolScope) for 3D polarization imaging of up to 25 focal planes simultaneously.

    Science.gov (United States)

    Abrahamsson, Sara; McQuilken, Molly; Mehta, Shalin B; Verma, Amitabh; Larsch, Johannes; Ilic, Rob; Heintzmann, Rainer; Bargmann, Cornelia I; Gladfelter, Amy S; Oldenbourg, Rudolf

    2015-03-23

    We have developed an imaging system for 3D time-lapse polarization microscopy of living biological samples. Polarization imaging reveals the position, alignment and orientation of submicroscopic features in label-free as well as fluorescently labeled specimens. Optical anisotropies are calculated from a series of images where the sample is illuminated by light of different polarization states. Due to the number of images necessary to collect both multiple polarization states and multiple focal planes, 3D polarization imaging is most often prohibitively slow. Our MF-PolScope system employs multifocus optics to form an instantaneous 3D image of up to 25 simultaneous focal-planes. We describe this optical system and show examples of 3D multi-focus polarization imaging of biological samples, including a protein assembly study in budding yeast cells.

  7. Fourier transform infrared spectrochemical imaging: review of design and applications with a focal plane array and multiple beam synchrotron radiation source.

    Science.gov (United States)

    Hirschmugl, Carol J; Gough, Kathleen M

    2012-05-01

    The beamline design, microscope specifications, and initial results from the new mid-infrared beamline (IRENI) are reviewed. Synchrotron-based spectrochemical imaging, as recently implemented at the Synchrotron Radiation Center in Stoughton, Wisconsin, demonstrates the new capability to achieve diffraction limited chemical imaging across the entire mid-infrared region, simultaneously, with high signal-to-noise ratio. IRENI extracts a large swath of radiation (320 hor. × 25 vert. mrads(2)) to homogeneously illuminate a commercial infrared (IR) microscope equipped with an IR focal plane array (FPA) detector. Wide-field images are collected, in contrast to single-pixel imaging from the confocal geometry with raster scanning, commonly used at most synchrotron beamlines. IRENI rapidly generates high quality, high spatial resolution data. The relevant advantages (spatial oversampling, speed, sensitivity, and signal-to-noise ratio) are discussed in detail and demonstrated with examples from a variety of disciplines, including formalin-fixed and flash-frozen tissue samples, live cells, fixed cells, paint cross-sections, polymer fibers, and novel nanomaterials. The impact of Mie scattering corrections on this high quality data is shown, and first results with a grazing angle objective are presented, along with future enhancements and plans for implementation of similar, small-scale instruments.

  8. Eliminating accommodation-convergence conflicts in stereoscopic displays: Can multiple-focal-plane displays elicit continuous and consistent vergence and accommodation responses?

    Science.gov (United States)

    MacKenzie, Kevin J.; Watt, Simon J.

    2010-02-01

    Conventional stereoscopic displays present images at a fixed focal distance. Depth variations in the depicted scene therefore result in conflicts between the stimuli to vergence and to accommodation. The resulting decoupling of accommodation and vergence responses can cause adverse consequences, including reduced stereo performance, difficulty fusing binocular images, and fatigue and discomfort. These problems could be eliminated if stereo displays could present correct focus cues. A promising approach to achieving this is to present each eye with a sum of images presented at multiple focal planes, and to approximate continuous variations in focal distance by distributing light energy across image planes - a technique referred to as depth-filtering1. Here we describe a novel multi-plane display in which we can measure accommodation and vergence responses. We report an experiment in which we compare these oculomotor responses to real stimuli and depth-filtered simulations of the same distance. Vergence responses were generally similar across conditions. Accommodation responses to depth-filtered images were inaccurate, however, showing an overshoot of the target, particularly in response to a small step-change in stimulus distance. This is surprising because we have previously shown that blur-driven accommodation to the same stimuli, viewed monocularly, is accurate and reliable. We speculate that an initial convergence-driven accommodation response, in combination with a weaker accommodative stimulus from depth-filtered images, leads to this overshoot. Our results suggest that stereoscopic multi-plane displays can be effective, but require smaller image-plane separations than monocular accommodation responses suggest.

  9. A TRP Channel in the Lysosome Regulates Large Particle Phagocytosis via Focal Exocytosis

    OpenAIRE

    2013-01-01

    Phagocytosis of large extracellular particles such as apoptotic bodies requires delivery of the intracellular endosomal and lysosomal membranes to form plasmalemmal pseudopods. Here we identified Mucolipin TRP channel 1 (TRPML1) as the key lysosomal Ca2+ channel regulating focal exocytosis and phagosome biogenesis. Both particle ingestion and lysosomal exocytosis are inhibited by synthetic TRPML1 blockers, and are defective in macrophages isolated from TRPML1 knockout mice. Furthermore, TRPML...

  10. The coronagraphic Modal Wavefront Sensor: a hybrid focal-plane sensor for the high-contrast imaging of circumstellar environments

    Science.gov (United States)

    Wilby, M. J.; Keller, C. U.; Snik, F.; Korkiakoski, V.; Pietrow, A. G. M.

    2017-01-01

    The raw coronagraphic performance of current high-contrast imaging instruments is limited by the presence of a quasi-static speckle (QSS) background, resulting from instrumental Non-Common Path Errors (NCPEs). Rapid development of efficient speckle subtraction techniques in data reduction has enabled final contrasts of up to 10-6 to be obtained, however it remains preferable to eliminate the underlying NCPEs at the source. In this work we introduce the coronagraphic Modal Wavefront Sensor (cMWS), a new wavefront sensor suitable for real-time NCPE correction. This combines the Apodizing Phase Plate (APP) coronagraph with a holographic modal wavefront sensor to provide simultaneous coronagraphic imaging and focal-plane wavefront sensing with the science point-spread function. We first characterise the baseline performance of the cMWS via idealised closed-loop simulations, showing that the sensor is able to successfully recover diffraction-limited coronagraph performance over an effective dynamic range of ±2.5 radians root-mean-square (rms) wavefront error within 2-10 iterations, with performance independent of the specific choice of mode basis. We then present the results of initial on-sky testing at the William Herschel Telescope, which demonstrate that the sensor is capable of NCPE sensing under realistic seeing conditions via the recovery of known static aberrations to an accuracy of 10 nm (0.1 radians) rms error in the presence of a dominant atmospheric speckle foreground. We also find that the sensor is capable of real-time measurement of broadband atmospheric wavefront variance (50% bandwidth, 158 nm rms wavefront error) at a cadence of 50 Hz over an uncorrected telescope sub-aperture. When combined with a suitable closed-loop adaptive optics system, the cMWS holds the potential to deliver an improvement of up to two orders of magnitude over the uncorrected QSS floor. Such a sensor would be eminently suitable for the direct imaging and spectroscopy of

  11. Short wave infrared InGaAs focal plane arrays detector: the performance optimization of photosensitive element

    Science.gov (United States)

    Gao, Xin-jiang; Tang, Zun-lie; Zhang, Xiu-chuan; Chen, Yang; Jiang, Li-qun; Cheng, Hong-bing

    2009-07-01

    Significant progress has been achieved in technology of the InGaAs focal plane arrays (FPA) detector operating in short wave infrared (SWIR) last two decades. The no cryogenic cooling, low manufacturing cost, low power, high sensitivity and maneuverability features inherent of InGaAs FPA make it as a mainstream SWIR FPA in a variety of critical military, national security, aerospace, telecommunications and industrial applications. These various types of passive image sensing or active illumination image detecting systems included range-gated imaging, 3-Dimensional Ladar, covert surveillance, pulsed laser beam profiling, machine vision, semiconductor inspection, free space optical communications beam tracker, hyperspectroscopy imaging and many others. In this paper the status and perspectives of hybrid InGaAs FPA which is composed of detector array (PDA) and CMOS readout integrate circuit (ROIC) are reviewed briefly. For various low light levels applications such as starlight or night sky illumination, we have made use of the interface circuit of capacitive feedback transimpedance amplifier (CTIA) in which the integration capacitor was adjustable, therefore implements of the physical and electrical characteristics matches between detector arrays and readout intergrate circuit was achieved excellently. Taking into account the influences of InGaAs detector arrays' optoelectronic characteristics on performance of the FPA, we discussed the key parameters of the photodiode in detailed, and the tradeoff between the responsivity, dark current, impedance at zero bias and junction capacitance of photosensitive element has been made to root out the impact factors. As a result of the educed approach of the photodiode's characteristics optimizing which involve with InGaAs PDA design and process, a high performance InGaAs FPA of 30um pixel pitch and 320×256 format has been developed of which the response spectrum range over 0.9um to 1.7um, the mean peak detectivity (λ=1.55

  12. The translated conceptual survey of physics / stablization of the focal plane in two photon excitation fluorescence microscopy

    Science.gov (United States)

    Wada, Asma

    excitation wavelengths in the near infrared (NIR). The (NIR) wavelength regime, 750- 1100nm, penetrates deep (>100 μm) into tissue, and has been used to image to depths of up to 1 mm. Further, the longer excitation wavelengths are less absorbing than the traditional ultraviolet wavelengths used in confocal microscopy, and are consequently less damaging. As a result, (TPEF) is presently the preferred tool for visualizing dynamics by biologists. One important aspect of imaging living systems, however, is that they move! This adds to the challenge of trying to study some particular biological function(s). This thesis begins to address this issue by combining a simple micro controller circuit that can be linked to a remote focusing scheme that will make it possible to lock a focal plane to a specific depth inside a living, moving specimen.

  13. Studies on design of 351  nm focal plane diagnostic system prototype and focusing characteristic of SGII-upgraded facility at half achievable energy performance.

    Science.gov (United States)

    Liu, Chong; Ji, Lailin; Yang, Lin; Zhao, Dongfeng; Zhang, Yanfeng; Liu, Dong; Zhu, Baoqiang; Lin, Zunqi

    2016-04-01

    In order to obtain the intensity distribution of a 351 nm focal spot and smoothing by spectral dispersion (SSD) focal plane profile of a SGII-upgraded facility, a type of off-axis imaging system with three spherical mirrors, suitable for a finite distance source point to be imaged near the diffraction limit has been designed. The quality factor of the image system is 1.6 times of the diffraction limit tested by a 1053 nm point source. Because of the absence of a 351 nm point source, we can use a Collins diffraction imaging integral with respect to λ=351  nm, corresponding to a quality factor that is 3.8 times the diffraction limit at 351 nm. The calibration results show that at least the range of ±10  mrad of view field angle and ±50  mm along the axial direction around the optimum object distance can be satisfied with near diffraction limited image that is consistent with the design value. Using this image system, the No. 2 beam of the SGII-upgraded facility has been tested. The test result of the focal spot of final optics assembly (FOA) at 351 nm indicates that about 80% of energy is encompassed in 14.1 times the diffraction limit, while the output energy of the No. 2 beam is 908 J at 1053 nm. According to convolution theorem, the true value of a 351 nm focal spot of FOA is about 12 times the diffraction limit because of the influence of the quality factor. Further experimental studies indicate that the RMS value along the smoothing direction is less than 15.98% in the SSD spot test experiment. Computer simulations show that the quality factor of the image system used in the experiment has almost no effect on the SSD focal spot test. The image system can remarkably distort the SSD focal spot distribution under the circumstance of the quality factor 15 times worse than the diffraction limit. The distorted image shows a steep slope in the contour of the SSD focal spot along the smoothing direction that otherwise has a relatively flat top region

  14. Interface and facet control during Czochralski growth of (111) InSb crystals for cost reduction and yield improvement of IR focal plane array substrates

    Science.gov (United States)

    Gray, Nathan W.; Perez-Rubio, Victor; Bolke, Joseph G.; Alexander, W. B.

    2014-10-01

    Focal plane arrays (FPAs) made on InSb wafers are the key cost-driving component in IR imaging systems. The electronic and crystallographic properties of the wafer directly determine the imaging device performance. The "facet effect" describes the non-uniform electronic properties of crystals resulting from anisotropic dopant segregation during bulk growth. When the segregation coefficient of dopant impurities changes notably across the melt/solid interface of a growing crystal the result is non-uniform electronic properties across wafers made from these crystals. The effect is more pronounced in InSb crystals grown on the (111) axis compared with other orientations and crystal systems. FPA devices made on these wafers suffer costly yield hits due to inconsistent device response and performance. Historically, InSb crystal growers have grown approximately 9-19 degree off-axis from the (111) to avoid the facet effect and produced wafers with improved uniformity of electronic properties. It has been shown by researchers in the 1960s that control of the facet effect can produce uniform small diameter crystals. In this paper, we share results employing a process that controls the facet effect when growing large diameter crystals from which 4, 5, and 6" wafers can be manufactured. The process change resulted in an increase in wafers yielded per crystal by several times, all with high crystal quality and uniform electronic properties. Since the crystals are grown on the (111) axis, manufacturing (111) oriented wafers is straightforward with standard semiconductor equipment and processes common to the high-volume silicon wafer industry. These benefits result in significant manufacturing cost savings and increased value to our customers.

  15. Modeling and optimization of the antenna system with focal plane array for the new generation radio telescopes with wide field of view

    CERN Document Server

    Iupikov, O

    2016-01-01

    The model of the reflector antenna system with focal plane array, low-noise amplifier and beamformer is developed in the work. The beamformer strategy is suggested to reduce the receiving sensitivity ripple inside field of view of the telescope, while the sensitivity itself drops slightly (less than 10%). The system APERTIF (which is currently under development in Netherlands Institute For Radioastronomy, ASTRON) has been analyzed using developed model, and numerical results are presented. The obtained numerical results have been verified experimentally in anechoic chamber as well as on one of the dishes of the Westerbork Synthesis Radio Telescope (all measurements have been done in ASTRON).

  16. 15-micro-m 128 x 128 GaAs/Al(x)Ga(1-x) As Quantum Well Infrared Photodetector Focal Plane Array Camera

    Science.gov (United States)

    Gunapala, Sarath D.; Park, Jin S.; Sarusi, Gabby; Lin, True-Lon; Liu, John K.; Maker, Paul D.; Muller, Richard E.; Shott, Craig A.; Hoelter, Ted

    1997-01-01

    In this paper, we discuss the development of very sensitive, very long wavelength infrared GaAs/Al(x)Ga(1-x)As quantum well infrared photodetectors (QWIP's) based on bound-to-quasi-bound intersubband transition, fabrication of random reflectors for efficient light coupling, and the demonstration of a 15 micro-m cutoff 128 x 128 focal plane array imaging camera. Excellent imagery, with a noise equivalent differential temperature (N E(delta T)) of 30 mK has been achieved.

  17. The Mechanical Design of a Kinematic Mount for the Mid Infrared Instrument Focal Plane Module on the James Webb Space Telescope

    Science.gov (United States)

    Thelen, Michael P.; Moore, Donald M.

    2009-01-01

    The detector assembly for the Mid Infrared Instrument (MIRI) of the James Webb Space Telescope (JWST) is mechanically supported in the Focal Plane Module (FPM) Assembly with an efficient hexapod design. The kinematic mount design allows for precision adjustment of the detector boresight to assembly alignment fiducials and maintains optical alignment requirements during flight conditions of launch and cryogenic operations below 7 Kelvin. This kinematic mounting technique is able to be implemented in a variety of optical-mechanical designs and is capable of micron level adjustment control and stability over wide dynamic and temperature ranges.

  18. Synchrotron Infrared Confocal Microspectroscopic Spatial Resolution or a Customized Synchrotron/focal Plane Array System Enhances Chemical Imaging of Biological Tissue or Cells

    Energy Technology Data Exchange (ETDEWEB)

    D Wetzel; M Nasse; =

    2011-12-31

    Spectroscopy and spatially resolved chemical imaging of biological materials using an infrared microscope is greatly enhanced with confocal image plane masking to 5-6 {mu} with a third generation microspectrometer and illumination with a synchrotron radiation source compared to globar illuminated and array detection or singly masked system. Steps toward this instrumental achievement are illustrated with spectra and images of biological tissue sections, including single cells, brain, aorta, and grain specimens. A recent, customized synchrotron infrared microspectrometer installation enables focal plane array detection to achieve both rapid and high definition chemical imaging. Localization of the ester carbonyl population in single modified starch granules was used to provide direct comparison of the two advanced imaging capabilities.

  19. Synchrotron infrared confocal microspectroscopic spatial resolution or a customized synchrotron/focal plane array system enhances chemical imaging of biological tissue or cells

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, David L., E-mail: dwetzel@ksu.edu [Microbeam Molecular Spectroscopy Laboratory, Kansas State University, Manhattan, KS (United States); Nasse, Michael J. [Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI (United States); Synchrotron Radiation Center, University of Wisconsin-Madison, Stoughton, WI (United States)

    2011-09-01

    Spectroscopy and spatially resolved chemical imaging of biological materials using an infrared microscope is greatly enhanced with confocal image plane masking to 5-6 {mu}m with a third generation microspectrometer and illumination with a synchrotron radiation source compared to globar illuminated and array detection or singly masked system. Steps toward this instrumental achievement are illustrated with spectra and images of biological tissue sections, including single cells, brain, aorta, and grain specimens. A recent, customized synchrotron infrared microspectrometer installation enables focal plane array detection to achieve both rapid and high definition chemical imaging. Localization of the ester carbonyl population in single modified starch granules was used to provide direct comparison of the two advanced imaging capabilities.

  20. Optimizing snake locomotion in the plane. II. Large transverse friction

    CERN Document Server

    Alben, Silas

    2013-01-01

    We determine analytically the form of optimal snake locomotion when the coefficient of transverse friction is large, the typical regime for biological and robotic snakes. We find that the optimal snake motion is a retrograde traveling wave, with a wave amplitude that decays as the -1/4 power of the coefficient of transverse friction. This result agrees well with our numerical computations.

  1. Focal-Plane Sensing-Processing: A Power-Efficient Approach for the Implementation of Privacy-Aware Networked Visual Sensors

    Directory of Open Access Journals (Sweden)

    Jorge Fernández-Berni

    2014-08-01

    Full Text Available The capture, processing and distribution of visual information is one of the major challenges for the paradigm of the Internet of Things. Privacy emerges as a fundamental barrier to overcome. The idea of networked image sensors pervasively collecting data generates social rejection in the face of sensitive information being tampered by hackers or misused by legitimate users. Power consumption also constitutes a crucial aspect. Images contain a massive amount of data to be processed under strict timing requirements, demanding high-performance vision systems. In this paper, we describe a hardware-based strategy to concurrently address these two key issues. By conveying processing capabilities to the focal plane in addition to sensing, we can implement privacy protection measures just at the point where sensitive data are generated. Furthermore, such measures can be tailored for efficiently reducing the computational load of subsequent processing stages. As a proof of concept, a full-custom QVGA vision sensor chip is presented. It incorporates a mixed-signal focal-plane sensing-processing array providing programmable pixelation of multiple image regions in parallel. In addition to this functionality, the sensor exploits reconfigurability to implement other processing primitives, namely block-wise dynamic range adaptation, integral image computation and multi-resolution filtering. The proposed circuitry is also suitable to build a granular space, becoming the raw material for subsequent feature extraction and recognition of categorized objects.

  2. Focal-plane sensing-processing: a power-efficient approach for the implementation of privacy-aware networked visual sensors.

    Science.gov (United States)

    Fernández-Berni, Jorge; Carmona-Galán, Ricardo; del Río, Rocío; Kleihorst, Richard; Philips, Wilfried; Rodríguez-Vázquez, Ángel

    2014-08-19

    The capture, processing and distribution of visual information is one of the major challenges for the paradigm of the Internet of Things. Privacy emerges as a fundamental barrier to overcome. The idea of networked image sensors pervasively collecting data generates social rejection in the face of sensitive information being tampered by hackers or misused by legitimate users. Power consumption also constitutes a crucial aspect. Images contain a massive amount of data to be processed under strict timing requirements, demanding high-performance vision systems. In this paper, we describe a hardware-based strategy to concurrently address these two key issues. By conveying processing capabilities to the focal plane in addition to sensing, we can implement privacy protection measures just at the point where sensitive data are generated. Furthermore, such measures can be tailored for efficiently reducing the computational load of subsequent processing stages. As a proof of concept, a full-custom QVGA vision sensor chip is presented. It incorporates a mixed-signal focal-plane sensing-processing array providing programmable pixelation of multiple image regions in parallel. In addition to this functionality, the sensor exploits reconfigurability to implement other processing primitives, namely block-wise dynamic range adaptation, integral image computation and multi-resolution filtering. The proposed circuitry is also suitable to build a granular space, becoming the raw material for subsequent feature extraction and recognition of categorized objects.

  3. Transarterial embolisation of a large focal nodular hyperplasia, using microspheres, in a paediatric patient.

    Science.gov (United States)

    Oliveira, Catarina; Gil-Agostinho, Alfredo; Gonçalves, Isabel; Noruegas, Maria José

    2015-07-10

    Benign liver tumours are uncommon in children, haemangiomas being the most frequent. Focal nodular hyperplasia (FNH) represents about 2% of paediatric liver tumours. In children, as in adults, a conservative approach is generally recommended. However, large lesions (greater than 5 cm) are more frequent in the paediatric age group, and in these cases, as well as in growing lesions, surgical removal may be advised. Transarterial embolisation (TAE) has been a successful alternative option described in older patients, especially in cases where surgical removal is not possible. This minimally invasive procedure may also become an option in the paediatric group. The authors report the case of a boy with a large FNH treated with TAE using microspheres. 2015 BMJ Publishing Group Ltd.

  4. Determining temperature distribution in tissue in the focal plane of the high (>100 W/cm(2)) intensity focused ultrasound beam using phase shift of ultrasound echoes.

    Science.gov (United States)

    Karwat, Piotr; Kujawska, Tamara; Lewin, Peter A; Secomski, Wojciech; Gambin, Barbara; Litniewski, Jerzy

    2016-02-01

    In therapeutic applications of High Intensity Focused Ultrasound (HIFU) the guidance of the HIFU beam and especially its focal plane is of crucial importance. This guidance is needed to appropriately target the focal plane and hence the whole focal volume inside the tumor tissue prior to thermo-ablative treatment and beginning of tissue necrosis. This is currently done using Magnetic Resonance Imaging that is relatively expensive. In this study an ultrasound method, which calculates the variations of speed of sound in the locally heated tissue volume by analyzing the phase shifts of echo-signals received by an ultrasound scanner from this very volume is presented. To improve spatial resolution of B-mode imaging and minimize the uncertainty of temperature estimation the acoustic signals were transmitted and received by 8 MHz linear phased array employing Synthetic Transmit Aperture (STA) technique. Initially, the validity of the algorithm developed was verified experimentally in a tissue-mimicking phantom heated from 20.6 to 48.6 °C. Subsequently, the method was tested using a pork loin sample heated locally by a 2 MHz pulsed HIFU beam with focal intensity ISATA of 129 W/cm(2). The temperature calibration of 2D maps of changes in the sound velocity induced by heating was performed by comparison of the algorithm-determined changes in the sound velocity with the temperatures measured by thermocouples located in the heated tissue volume. The method developed enabled ultrasound temperature imaging of the heated tissue volume from the very inception of heating with the contrast-to-noise ratio of 3.5-12 dB in the temperature range 21-56 °C. Concurrently performed, conventional B-mode imaging revealed CNR close to zero dB until the temperature reached 50 °C causing necrosis. The data presented suggest that the proposed method could offer an alternative to MRI-guided temperature imaging for prediction of the location and extent of the thermal lesion prior to applying the

  5. RTIA readout circuit for infrared focal plane array using active resistor%有源电阻RTIA红外焦平面读出电路

    Institute of Scientific and Technical Information of China (English)

    胡滨; 李威; 李平; 阙滨城

    2012-01-01

    提出了一种基于有源电阻的电阻反馈跨导放大器(RTIA)红外焦平面读出电路,该电路采用工作在亚阈区的MOS管实现1011Ω以上的有源大电阻,不仅能与热释电红外探测器的高阻抗良好匹配,而且配合两管共源放大器可针对热释电微弱信号进行高增益电流放大.同时,简单的三管单元结构能够方便地置于像元之下,相比于采用特殊高阻材料实现的RTIA,不附加材料和工艺.经上华0.5 μmCMOS工艺流片验证,在5V电源电压下,该电路增益40 dB,输出摆幅3V,在高低温测试下表现出了良好的增益带宽稳定性,适用于PZT和BST等热释电大阵列探测器.%A Resistive Trans-impedance Amplifier (RTIA) readout circuit for Uncooled Focal Plane Array (UFPA) using active resistor was proposed in this paper. By using a sub-threshold MOSFET as a 1011 Ω and above feedback resistor, a high gain current amplifier could be realized by common source structure which consisted of two transistors. The simple three transistors could be easily integrated under pixel and it had good impedance matching with pyroelectric infrared detector. Compared with traditional RTIAs which use special high-resistance materials as feedback resistor, the novel RTIA was low cost because no additional materials and processes were needed. The circuit was successfully manufactured by 0.5 μm standard CMOS process of CSMC foundry. 40 dB gain and 3 V output swing were realized by this design and the gain and bandwidth of the chip kept stable during high and low temperature tests. So it can be used for large arrays pyroelectric detectors such as Lead Zirconate Titanate (PZT) and Barium Strontium Titanate (BST), etc.

  6. Distance equation of infrared focal plane array rotation search system%红外面阵旋转搜索系统作用距离方程

    Institute of Scientific and Technical Information of China (English)

    钱惟贤; 陈钱; 顾国华

    2011-01-01

    The infrared focal plane array rotation search system(IFPARSS) is controversial and denied by the mainstream view. In this paper, the multiple pixels' correlation (MPC) of IFPARSS in space domain and time doamin was studied. MPC was used to increase the SNR of the target effectively after the process of pixel's gray accumulation, and thus improve the target detecting distance. Moreover, according the MPC, the IFPARSS point target detecting distance equation was deduced. And through this equation, the superiorty of IFPARSS was proven. Then the simulations of distance equation were carried out. And the focal plane array search system with rotation and static state by distance range, the focal plane array search system and the linear array search system by the distance equation were compared. The simulation results show that the IFPARSS is useful and the view that denies the IFPARSS is wrong.%红外面阵旋转搜索系统一直倍受争议,文中对此进行了讨论.研究了红外面阵旋转搜索系统存在的多像元探测相关性,对多像元相关性进行相关像素灰度积累可以有效提高目标探测信噪比,并最终提升探测作用距离.基于多像元相关性,文中推导了面阵旋转搜索系统考虑多像元相关性的点源探测作用距离方程,以及考虑数据关联等作用的有效作用距离方程.对面阵旋转的作用距离方程、有效作用距离方程进行了仿真,同时对面阵旋转与静止时的作用距离、面阵旋转搜索系统和线阵旋转搜索系统的性能进行了比较.最终通过仿真数据证明了面阵旋转搜索系统的实用价值.

  7. Loss of spatial coherence and limiting of focal plane intensity by small-scale laser-beam filamentation

    Energy Technology Data Exchange (ETDEWEB)

    Schweinsberg, Aaron; Kuper, Jerry [The Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Boyd, Robert W. [The Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Department of Physics and School of Electrical Engineering and Computer Science, University of Ottawa, Ottawa, Ontario, Canda K1N 6N5 (Canada)

    2011-11-15

    We describe a nonlinear optical mechanism that leads to a decrease of the degree of (transverse) spatial coherence of a laser beam as a function of propagation distance. This prediction is in direct contrast with those of the van Cittert-Zernike theorem, which applies to propagation through a linear, homogeneous material. The mechanism by which coherence is lost is the growth of small phase irregularities initially present on the laser wave front. We develop a detailed theoretical model of this effect and present experimental results that validate this model. The practical importance of this result is that by being able to controllably decrease the spatial coherence of a laser beam, one can limit the maximum intensity that is produced in its focal region. By limiting the intensity, one can prevent laser damage to bulk optical components or to sensitive photodetectors. This mechanism thus provides an alternative to current approaches of sensor protection based on optical power limiting.

  8. Autofocus technique for three-dimensional imaging, direct-detection laser radar using Geiger-mode avalanche photodiode focal-plane array.

    Science.gov (United States)

    Oh, Min Seok; Kong, Hong Jin; Kim, Tae Hoon; Jo, Sung Eun

    2010-12-15

    An autofocus technique is proposed for a three-dimensional imaging, direct-detection laser radar system that uses a Geiger-mode avalanche photodiode focal plane array (GmAPD-FPA). This technique is implemented by pointing laser pulses on a target of interest and observing its scattered photon distribution on a GmAPD-FPA. Measuring the standard deviation of the photon distribution on a GmAPD-FPA enables the best focus condition to be found. The feasibility of this technique is demonstrated experimentally by employing a 1 × 8 pixel GmAPD-FPA. It is shown that the spatial resolution improves when the GmAPD-FPA is located in the best focus position found by the autofocus technique.

  9. Division of focal plane polarimeter-based 3 × 4 Mueller matrix microscope: a potential tool for quick diagnosis of human carcinoma tissues

    Science.gov (United States)

    Chang, Jintao; He, Honghui; Wang, Ye; Huang, Yi; Li, Xianpeng; He, Chao; Liao, Ran; Zeng, Nan; Liu, Shaoxiong; Ma, Hui

    2016-05-01

    A polarization microscope is a useful tool to reveal the optical anisotropic nature of a specimen and can provide abundant microstructural information about samples. We present a division of focal plane (DoFP) polarimeter-based polarization microscope capable of simultaneously measuring both the Stokes vector and the 3×4 Mueller matrix with an optimal polarization illumination scheme. The Mueller matrix images of unstained human carcinoma tissue slices show that the m24 and m34 elements can provide important information for pathological observations. The characteristic features of the m24 and m34 elements can be enhanced by polarization staining under illumination by a circularly polarized light. Hence, combined with a graphics processing unit acceleration algorithm, the DoFP polarization microscope is capable of real-time polarization imaging for potential quick clinical diagnoses of both standard and frozen slices of human carcinoma tissues.

  10. 被动毫米波焦面阵成像技术%Passive millimeter wave focal plane array imaging technology

    Institute of Scientific and Technical Information of China (English)

    王楠楠; 邱景辉; 张鹏宇; 邓维波

    2011-01-01

    以安全检查为背景,研究了近距离被动毫米波焦面阵成像的关键技术.其中包括采用基模高斯波束法结合几何光学法分析系统准光路;设计多波束宽角扫描透镜天线;提出一种新型结构的介质棒天线,该天线易于排成紧密阵列且能够为透镜提供良好的照射;研制工作于Ka频段的高灵敏度、小型化直接检波式辐射计等.给出了20通道被动毫米波焦面阵成像系统的实验结果,表明该系统可用于室内近距离探测人体隐匿物品.%Under the background of safety inspection, the key technologies of near-range passive millimeter wave focal plane array imaging are studied. The analysis of the system quasi-optics were carried out using fundamental Gaussian beam method combined with geometrical optics method. A multi-beam wide-angle scanning lens antenna was designed. A new dielectric rod antenna was devised, which is prone to be aligned in close arrays and provide good radiation to the lens. Miniaturized direct-detection radiometers were fabricated with high-sensitive in Ka-band . Experimental results of the 20-chan-nel passive millimeter wave focal plane array imaging system are presented, which can be used to detect hidden objects on human bodies in near range indoors.

  11. Controlling dental enamel-cavity ablation depth with optimized stepping parameters along the focal plane normal using a three axis, numerically controlled picosecond laser.

    Science.gov (United States)

    Yuan, Fusong; Lv, Peijun; Wang, Dangxiao; Wang, Lei; Sun, Yuchun; Wang, Yong

    2015-02-01

    The purpose of this study was to establish a depth-control method in enamel-cavity ablation by optimizing the timing of the focal-plane-normal stepping and the single-step size of a three axis, numerically controlled picosecond laser. Although it has been proposed that picosecond lasers may be used to ablate dental hard tissue, the viability of such a depth-control method in enamel-cavity ablation remains uncertain. Forty-two enamel slices with approximately level surfaces were prepared and subjected to two-dimensional ablation by a picosecond laser. The additive-pulse layer, n, was set to 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70. A three-dimensional microscope was then used to measure the ablation depth, d, to obtain a quantitative function relating n and d. Six enamel slices were then subjected to three dimensional ablation to produce 10 cavities, respectively, with additive-pulse layer and single-step size set to corresponding values. The difference between the theoretical and measured values was calculated for both the cavity depth and the ablation depth of a single step. These were used to determine minimum-difference values for both the additive-pulse layer (n) and single-step size (d). When the additive-pulse layer and the single-step size were set 5 and 45, respectively, the depth error had a minimum of 2.25 μm, and 450 μm deep enamel cavities were produced. When performing three-dimensional ablating of enamel with a picosecond laser, adjusting the timing of the focal-plane-normal stepping and the single-step size allows for the control of ablation-depth error to the order of micrometers.

  12. A TRP channel in the lysosome regulates large particle phagocytosis via focal exocytosis.

    Science.gov (United States)

    Samie, Mohammad; Wang, Xiang; Zhang, Xiaoli; Goschka, Andrew; Li, Xinran; Cheng, Xiping; Gregg, Evan; Azar, Marlene; Zhuo, Yue; Garrity, Abigail G; Gao, Qiong; Slaugenhaupt, Susan; Pickel, Jim; Zolov, Sergey N; Weisman, Lois S; Lenk, Guy M; Titus, Steve; Bryant-Genevier, Marthe; Southall, Noel; Juan, Marugan; Ferrer, Marc; Xu, Haoxing

    2013-09-16

    Phagocytosis of large extracellular particles such as apoptotic bodies requires delivery of the intracellular endosomal and lysosomal membranes to form plasmalemmal pseudopods. Here, we identified mucolipin TRP channel 1 (TRPML1) as the key lysosomal Ca2+ channel regulating focal exocytosis and phagosome biogenesis. Both particle ingestion and lysosomal exocytosis are inhibited by synthetic TRPML1 blockers and are defective in macrophages isolated from TRPML1 knockout mice. Furthermore, TRPML1 overexpression and TRPML1 agonists facilitate both lysosomal exocytosis and particle uptake. Using time-lapse confocal imaging and direct patch clamping of phagosomal membranes, we found that particle binding induces lysosomal PI(3,5)P2 elevation to trigger TRPML1-mediated lysosomal Ca2+ release specifically at the site of uptake, rapidly delivering TRPML1-resident lysosomal membranes to nascent phagosomes via lysosomal exocytosis. Thus phagocytic ingestion of large particles activates a phosphoinositide- and Ca2+-dependent exocytosis pathway to provide membranes necessary for pseudopod extension, leading to clearance of senescent and apoptotic cells in vivo.

  13. Focal Plane Assembly and Calibrating of CMOS Star Sensor%CMOS星敏感器焦平面装配及标定

    Institute of Scientific and Technical Information of China (English)

    钟兴; 金光; 王栋; 邢飞

    2011-01-01

    Focal plane's misalignment is analyzed theoretically to match the requirement of high precision CMOS star sensor. System for assembly and calibrating measurement of CMOS star sensor is established. Defocusing distance and tilt of detector plane are acquired by on-axis and off-axis star sensor imaging test through collimator's image plane moving. Some CMOS star sensor with 50 mm focal length, F/l .25, and 20° field of view is successfully assembled under direction of testing data. Defocusing distance is less than 0.01 mm, and tilt is less than 2'. Principal distance test and distortion calibration are done with measuring system. Principal distance is calculated to be 49.77 mm, and the error is 0.007 2 mm. Distortion of star sensor system is calibrated by third order polynomial fitting data, and the residual error caused by distortion can be reduced to 6.6" when measuring single star.%针对高精度CMOS星敏感器的使用要求,本文对焦平面装配的误差进行了理论分析,搭建了CMOS星敏感器装配及标定测试系统,利用长焦距平行光管像面移动测量方法进行了星敏感器轴上和轴外的星点成像,获取了焦平面离焦量及倾斜数据.在这些数据指导下,成功完成了对某焦距50 mm,相对孔径1/1.25,全视场20°的CMOS星敏感器的焦平面装配,轴上点离焦小于0.01 mm,倾斜小于2′.对装配后的星敏感器在高精度气浮转台上进行了主距测试和畸变标定,标定计算得到主距为49.77 mm,精度0.007 2 mm.利用三阶多项式拟合的方法对系统畸变进行了修正,修正后的残余畸变对单个星点测量的精度影响可减小到6.6”左右,满足高精度星敏感器的使用要求.

  14. Simultaneous quantitative evaluation of in-plane and out-of-plane deformation by use of a carrier method of large image-shearing shearography

    Institute of Scientific and Technical Information of China (English)

    Ping Sun; Ruijin Liu; Qing Han; Xiaofeng Wang

    2006-01-01

    A carrier method for separating out-of-plane displacement from in-plane components based on large imageshearing shearography is presented. A reference surface is fixed on the side of a test object. They are illuminated by two expanded symmetric illuminations respectively. The carrier is introduced by rotating the reference surface to modulate the displacement of an object. By using Fourier transform to demodulate the modulated fringe pattern, two phase maps, which include out-of-plane and in-plane displacements, can be obtained. Then the out-of-plane displacement can be easily separated from in-plane displacement by subtraction and addition of the two unwrapped phase distributions. The principle of the method is presented and proved by a typical three-point-bending experiment. Experimental results show that the method enjoys high visibility of carrier fringes. The system does not need a special beam as a reference light and has simple optical setup.

  15. Simulation research on the process of large scale ship plane segmentation intelligent workshop

    Science.gov (United States)

    Xu, Peng; Liao, Liangchuang; Zhou, Chao; Xue, Rui; Fu, Wei

    2017-04-01

    Large scale ship plane segmentation intelligent workshop is a new thing, and there is no research work in related fields at home and abroad. The mode of production should be transformed by the existing industry 2.0 or part of industry 3.0, also transformed from "human brain analysis and judgment + machine manufacturing" to "machine analysis and judgment + machine manufacturing". In this transforming process, there are a great deal of tasks need to be determined on the aspects of management and technology, such as workshop structure evolution, development of intelligent equipment and changes in business model. Along with them is the reformation of the whole workshop. Process simulation in this project would verify general layout and process flow of large scale ship plane section intelligent workshop, also would analyze intelligent workshop working efficiency, which is significant to the next step of the transformation of plane segmentation intelligent workshop.

  16. Influence of light sheet separation on SPIV measurement in a large field spanwise plane

    DEFF Research Database (Denmark)

    Foucaut, J M; Coudert, S.; Braud, C.

    2014-01-01

    guidelines for both setup and measurements of such flow configurations, a large region of overlap between two SPIV systems on the same laser light sheet is acquired in a plane normal to the streamwise direction of a high Reynolds turbulent boundary layer flow. A simple separation of the two light sheets......Stereoscopic particle image velocimetry (SPIV) is nowadays a well-established measurement technique for turbulent flows. However, the accuracy and the spatial resolution are still highly questionable in the presence of complex flow with both strong gradients and out-of-plane motions. To give...

  17. Derivatization technique to increase the spectral selectivity of two-dimensional Fourier transform infrared focal plane array imaging: analysis of binder composition in aged oil and tempera paint.

    Science.gov (United States)

    Zumbühl, Stefan; Scherrer, Nadim C; Eggenberger, Urs

    2014-01-01

    The interpretation of standard Fourier transform infrared spectra (FT-IR) on oil-based paint samples often suffers from interfering bands of the different compounds, namely, binder, oxidative aging products, carboxylates formed during aging, and several pigments and fillers. The distinction of the aging products such as ketone and carboxylic acid functional groups pose the next problem, as these interfere with the triglyceride esters of the oil. A sample preparation and derivatization technique using gaseous sulfur tetrafluoride (SF4), was thus developed with the aim to discriminate overlapping signals and achieve a signal enhancement on superposed compounds. Of particular interest in this context is the signal elimination of the broad carboxylate bands of the typical reaction products developing during the aging processes in oil-based paints, as well as signal interference originating from several typical pigments in this spectral range. Furthermore, it is possible to distinguish the different carbonyl-containing functional groups upon selective alteration. The derivatization treatment can be applied to both microsamples and polished cross sections. It increases the selectivity of the infrared spectroscopy technique in a fundamental manner and permits the identification and two-dimensional (2D) localization of binder components in aged paint samples at the micrometer scale. The combination of SF4 derivatization with high-resolution 2D FT-IR focal plane array (FPA) imaging delivers considerable advances to the study of micro-morphological processes involving organic compounds.

  18. Determination of charge-carrier diffusion length in the photosensing layer of HgCdTe n-on-p photovoltaic infrared focal plane array detectors

    Energy Technology Data Exchange (ETDEWEB)

    Vishnyakov, A. V.; Stuchinsky, V. A., E-mail: stuchin@isp.nsc.ru; Brunev, D. V.; Zverev, A. V.; Dvoretsky, S. A. [Institute of Semiconductor Physics, Russian Academy of Science, Siberian Division, 13, Acad. Lavrent' ev Avenue, Novosibirsk 630090 (Russian Federation)

    2014-03-03

    In the present paper, we propose a method for evaluating the bulk diffusion length of minority charge carriers in the photosensing layer of photovoltaic focal plane array (FPA) photodetectors. The method is based on scanning a strip-shaped illumination spot with one of the detector diodes at a low level of photocurrents j{sub ph} being registered; such scanning provides data for subsequent analysis of measured spot-scan profiles within a simple diffusion model. The asymptotic behavior of the effective (at j{sub ph} ≠ 0) charge-carrier diffusion length l{sub d} {sub eff} as a function of j{sub ph} for j{sub ph} → 0 inferred from our experimental data proved to be consistent with the behavior of l{sub d} {sub eff} vs j{sub ph} as predicted by the model, while the obtained values of the bulk diffusion length of minority carriers (electrons) in the p-HgCdTe film of investigated HgCdTe n-on-p FPA photodetectors were found to be in a good agreement with the previously reported carrier diffusion-length values for HgCdTe.

  19. Large scale flows in transitional plane Couette flow: a key ingredient of the spot growth mechanism

    CERN Document Server

    Couliou, M

    2015-01-01

    Using Particle Image Velocimetry (PIV) in a new experimental plane Couette flow, we investigate the dynamics of turbulent patches invading formerly laminar flows. We evidence experimentally for the first time in this geometry the existence of large scale flows. These flows appear as soon as laminar and turbulent domains coexist. Spectral analysis is used to study the dynamical evolution of these large scales as well as that of the small scales associated with turbulence. We show that large-scale flows grow before turbulent spots develop and we point out the crucial role they play in the growth mechanism and possibly also in the emergence of organised patterns.

  20. On the integrability of large N plane-wave matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    Klose, Thomas E-mail: thklose@aei.mpg.de; Plefka, Jan E-mail: plefka@aei.mpg.de

    2004-02-16

    We show the three-loop integrability of large N plane-wave matrix theory in a subsector of states comprised of two complex light scalar fields. This is done by diagonalizing the theory's Hamiltonian in perturbation theory and taking the large N limit. At one-loop level the result is known to be equal to the Heisenberg spin-1/2 chain, which is a well-known integrable system. Here, integrability implies the existence of hidden conserved charges and results in a degeneracy of parity pairs in the spectrum. In order to confirm integrability at higher loops, we show that this degeneracy is not lifted and that (corrected) conserved charges exist. Plane-wave matrix theory is intricately connected to N=4 super-Yang-Mills, as it arises as a consistent reduction of the gauge theory on a three-sphere. We find that after appropriately renormalizing the mass parameter of the plane-wave matrix theory the effective Hamiltonian is identical to the dilatation operator of N=4 super-Yang-Mills theory in the considered subsector. Our results therefore represent a strong support for the conjectured three-loop integrability of planar N=4 SYM and are in disagreement with a recent dual string theory finding. Finally, we study the stability of the large N integrability against nonsupersymmetric deformations of the model.

  1. Wind turbine wakes in forest and neutral plane wall boundary layer large-eddy simulations

    Science.gov (United States)

    Schröttle, Josef; Piotrowski, Zbigniew; Gerz, Thomas; Englberger, Antonia; Dörnbrack, Andreas

    2016-09-01

    Wind turbine wake flow characteristics are studied in a strongly sheared and turbulent forest boundary layer and a neutral plane wall boundary layer flow. The reference simulations without wind turbine yield similar results as earlier large-eddy simulations by Shaw and Schumann (1992) and Porte-Agel et al. (2000). To use the fields from the homogeneous turbulent boundary layers on the fly as inflow fields for the wind turbine wake simulations, a new and efficient methodology was developed for the multiscale geophysical flow solver EULAG. With this method fully developed turbulent flow fields can be achieved upstream of the wind turbine which are independent of the wake flow. The large-eddy simulations reproduce known boundary-layer statistics as mean wind profile, momentum flux profile, and eddy dissipation rate of the plane wall and the forest boundary layer. The wake velocity deficit is more asymmetric above the forest and recovers faster downstream compared to the velocity deficit in the plane wall boundary layer. This is due to the inflection point in the mean streamwise velocity profile with corresponding turbulent coherent structures of high turbulence intensity in the strong shear flow above the forest.

  2. Phase change thermal control design and verification of focal plane in aerial camera%航空相机焦面组件相变温控设计及验证

    Institute of Scientific and Technical Information of China (English)

    郭亮; 吴清文; 丁亚林; 张洪文; 张继超; 冷雪; 李延伟

    2013-01-01

    航空相机焦面组件是机载电子设备中具有严格温度要求的重要组件,其工作期间温度过高产生的热噪声和暗电流将导致成像质量下降。讨论分析了某型航空相机焦面组件热设计的特点,采用封装有相变材料的相变温控系统进行散热,根据结构特点和导热路径,给出了热设计方案。采用有限元数值分析方法,建立了热平衡方程和热分析计算模型,应用热分析软件IDEAS-TMG在给定温度边界条件下进行瞬态仿真分析,给出了组件的热响应性能。热分析结果表明:焦面组件和散热器工作温度范围分别为18~31.1℃、18~28.2℃。所获得的分析结果能够满足热控指标要求。最后通过热实验对采用相变温控系统的热设计方案进行了验证,验证实验结果与数值分析结果吻合较好,结果对比最大偏差均不超过5%,验证了数值分析的正确性和温度预示的有效性。实验过程中焦面组件和散热器工作温度范围分别为18~32.3℃、18~29.6℃。%Focal plane in aerial plane, which has strict temperature requirement, is an important component in airborne electronic devices. The quality imaging of focal plane will fall off due to thermal noise and dark current generated during its working process. The characteristic of thermal design for focal plane in aerial camera was discussed and analyzed. Phase change system encapsulating phase change material was adopted to eliminate heat. According to the design feature and heat transfer path in focal plane, thermal design scheme of component was given. Thermal equilibrium equation and numerical analysis model of the heat transfer in focal plane were established by finite element analysis method. Based on the given temperature boundary condition, transient-state thermal analysis of component was carried out through IDEAS-TMG, which was a finite element thermal analysis software. The thermal response performance of

  3. Large eddy simulation of a particle-laden turbulent plane jet

    Institute of Scientific and Technical Information of China (English)

    金晗辉; 罗坤; 樊建人; 岑可法

    2003-01-01

    Gas-solid two-phase turbulent plane jet is applied to many natural situations and in engineering systems. To predict the particle dispersion in the gas jet is of great importance in industrial applications and in the designing of engineering systems. A large eddy simulation of the two-phase plane jet was conducted to investigate the particle dispersion patterns. The particles with Stokes numbers equal to 0.0028, 0.3, 2.5, 28 (corresponding to particle diameter 1 μm, 10 μm, 30 μm, 100 μm, respectively) in Re=11 300 gas flow were studied. The simulation results of gas phase motion agreed well with previous experimental results. And the simulation results of the solid particles motion showed that particles with different Stokes number have different spatial dispersion; and that particles with intermediate Stokes number have the largest dispersion ratio.

  4. Large eddy simulation of a particle-laden turbulent plane jet.

    Science.gov (United States)

    Jin, Han-Hui; Luo, Kun; Fan, Jian-Ren; Cen, Ke-Fa

    2003-01-01

    Gas-solid two-phase turbulent plane jet is applied to many natural situations and in engineering systems. To predict the particle dispersion in the gas jet is of great importance in industrial applications and in the designing of engineering systems. A large eddy simulation of the two-phase plane jet was conducted to investigate the particle dispersion patterns. The particles with Stokes numbers equal to 0.0028, 0.3, 2.5, 28 (corresponding to particle diameter 1 microm, 10 microm, 30 microm, 100 microm, respectively) in Re = 11 300 gas flow were studied. The simulation results of gas phase motion agreed well with previous experimental results. And the simulation results of the solid particles motion showed that particles with different Stokes number have different spatial dispersion; and that particles with intermediate Stokes number have the largest dispersion ratio.

  5. Large eddy simulation of a particle—laden turbulent plane jet

    Institute of Scientific and Technical Information of China (English)

    金含辉; 罗坤; 樊建人; 岑可法

    2003-01-01

    Gas-solid two-phase turbulent plane jet is applied to many natural situations and in engineering systems.To predict the particle dispersion in the gas jet is of great importance in industrial applications and in the designing of engineering systems.A large eddy simulation of the two-phase plane jet eas conducted to in-vestigate the particle dispersion patterns.The particles with Stokes numbers equal to 0.0028,0.3,2.5,28(corresponding to particle diamster 1μm,10μm,30μm,100μm,respectively)in Re=11300 gas flow were strudied.The simulation results of gas phase motion agreed well with previous experimental results.And the simulation results of the solid particles motion showed that particles with different Stokes number have dif-ferent spatial dispersion;and that particles with intermediate Stokes number have the largest dispersion ratio.

  6. Application of color structured light pattern to measurement of large out-of-plane deformation

    Institute of Scientific and Technical Information of China (English)

    Xing Lü; Jun-Hong Zhou; Dong-Dong Liu; Jue Zhang

    2011-01-01

    Measurement of out-of-plane deformation is significant to understanding of the deflection mechanisms of the plate and tube structures.In this study,a new surface contouring technique with color structured light is applied to measure the out-of-plane deformation of structures with one-shot projection.Through color fringe recognizing,decoding and triangulation processing for the captured images corresponding to each deformation state,the feasibility of the method is testified by the measurement of elastic deflections of a flexible square plate,showing good agreement with those from the calibrated displacement driver.The plastic deformation of two alloy aluminum rectangular tubes is measured to show the technique application to surface topographic evaluation of the buckling structures with large displacements.

  7. Cost-Driven Design of a Large Scale X-Plane

    Science.gov (United States)

    Welstead, Jason R.; Frederic, Peter C.; Frederick, Michael A.; Jacobson, Steven R.; Berton, Jeffrey J.

    2017-01-01

    A conceptual design process focused on the development of a low-cost, large scale X-plane was developed as part of an internal research and development effort. One of the concepts considered for this process was the double-bubble configuration recently developed as an advanced single-aisle class commercial transport similar in size to a Boeing 737-800 or Airbus A320. The study objective was to reduce the contractor cost from contract award to first test flight to less than $100 million, and having the first flight within three years of contract award. Methods and strategies for reduced cost are discussed.

  8. Confirmation of Auger-1 Minority-Carrier Lifetimes in Hg0.77Cd0.23Te and Prediction of Dark Current for Long-Wave Infrared Focal-Plane Arrays

    Science.gov (United States)

    Destefanis, V.; Kerlain, A.

    2016-09-01

    Minority-carrier lifetime measurements have been carried out on Hg0.77Cd0.23Te (111)B materials with gap suitable for detection in the Long-Wave Infrared (LWIR) band. The materials were grown on top of CdZnTe substrates using a liquid-phase epitaxy (LPE) process. From measurements done at 80 K, a clear difference in terms of minority-carrier lifetimes was obtained, as expected, between p-intrinsic (≤5 ns) and n-extrinsic doped samples (420 ns). Minority-carrier lifetimes were also measured as a function of temperature for the n-type samples. Auger-1-limited lifetimes were demonstrated over a wide temperature range (from 80 K to 300 K) with negligible Radiative or Shockley-Read-Hall lifetime contributions. Predictions of dark current densities are made from those lifetime measurements, assuming an Auger-1-limited lifetime. The agreement is very good between the predictions and dark current densities measured from p-on- n 640 × 512 pixels LWIR HgCdTe focal-plane arrays with 15- μm pitch from SOFRADIR, Agreement between predicted and measured dark currents and Rule'07 for LWIR is also demonstrated herein. Finally, minority-carrier lifetime measurements are demonstrated as a predictive method for focal-plane array performance. State-of-the-art dark currents from SOFRADIR p-on- n LWIR focal-plane arrays based upon high-quality HgCdTe materials are also illustrated.

  9. Identification of microplastic in effluents of waste water treatment plants using focal plane array-based micro-Fourier-transform infrared imaging.

    Science.gov (United States)

    Mintenig, S M; Int-Veen, I; Löder, M G J; Primpke, S; Gerdts, G

    2017-01-01

    The global presence of microplastic (MP) in aquatic ecosystems has been shown by various studies. However, neither MP concentrations nor their sources or sinks are completely known. Waste water treatment plants (WWTPs) are considered as significant point sources discharging MP to the environment. This study investigated MP in the effluents of 12 WWTPs in Lower Saxony, Germany. Samples were purified by a plastic-preserving enzymatic-oxidative procedure and subsequent density separation using a zinc chloride solution. For analysis, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FT-IR) and focal plane array (FPA)-based transmission micro-FT-IR imaging were applied. This allowed the identification of polymers of all MP down to a size of 20 μm. In all effluents MP was found with quantities ranging from 0 to 5 × 10(1) m(-3) MP > 500 μm and 1 × 10(1) to 9 × 10(3) m(-3) MP < 500 μm. By far, polyethylene was the most frequent polymer type in both size classes. Quantities of synthetic fibres ranged from 9 × 10(1) to 1 × 10(3) m(-3) and were predominantly made of polyester. Considering the annual effluxes of tested WWTPs, total discharges of 9 × 10(7) to 4 × 10(9) MP particles and fibres per WWTP could be expected. Interestingly, one tertiary WWTP had an additionally installed post-filtration that reduced the total MP discharge by 97%. Furthermore, the sewage sludge of six WWTPs was examined and the existence of MP, predominantly polyethylene, revealed. Our findings suggest that WWTPs could be a sink but also a source of MP and thus can be considered to play an important role for environmental MP pollution. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Combined Nonuniformity Correction Algorithm of Infrared Focal Plane Arrays%红外焦平面联合非均匀性校正算法

    Institute of Scientific and Technical Information of China (English)

    洪闻青; 杨南生; 王晓东; 苏俊波; 苏兰; 胡志斌

    2011-01-01

    分别分析了红外焦平面阵列(IRFPA)基于定标的非均匀性校正(NUC)算法和基于场景的NUC算法的优势和问题.在此基础上提出了联合NUC算法,其中利用基于定标的两点校正法来初步消除探测器的非均匀性,然后再采用基于场景的时域高通校正法和新型自适应滤波校正法来抑制探测器非均匀性参数漂移的影响,同时减弱系统噪声对成像质量的破坏.实验结果表明,与两点法、时域高通法以及传统自适应滤波法等具有较大工程应用价值的NUC算法相比,联合NUC算法具有稳定而且性能更为优良的校正效果.%The advantages and disadvantages in nonuniformity correction (NUC) algorithms based on calibration and scene of infrared focal plane arrays (IRFPA) are analysed separately. The combined NUC algorithm is presented.Two-point NUC algorithm based on calibration is adopted to remove the nonuniformity of the detector simply. The influences of detectors' NUC parameters which will change with time are weakened by using the scene-based temporal high-pass filter algorithm and new-style adaptive filter algorithm. The disadvantages for image quality introduced by ynoises are weakened too. The experimental results show that the combined NUC algorithm is more stable and better than some NUC algorithms with great value in project applications, such as two point NUC algorithm, temporal highpass filter NUC algorithm and former adaptive filter NUC algorithm.

  11. Focusing Mechanism of Big Dimension Focal Plane%一种适用于大尺寸焦面的调焦机构

    Institute of Scientific and Technical Information of China (English)

    崔永鹏; 何欣; 王忠善

    2015-01-01

    A kind of focusing structure making use of two worm wheels and two screws was designed,which has tall frequency and tall precision to compensate the shortcomings of traditional focusing structures.According to theory of mechanics of materials, the relation between the amount of supporting and the member’s distortion was analyzed. According to advantage of two supports which tested the direction precision and was tested in a dynamic environment, we had designed and manufactured a new focusing structure. The result of test proves that the frequency in three directions of the focusing mechanism are higher than 220 Hz, and the direction precision is better than 2 after the dynamic environment testing. The focusing mechanism has nice capability to stand against vibration, tall precision, smooth moving, and high dependability, which can make use of fixated and exact removing big dimension focal plane.%设计了一种采用双蜗轮蜗杆、双滚珠丝杠配合的两点驱动式调焦机构,弥补了传统调焦机构组件基频低、指向精度差的缺点。依据材料力学理论,分析了支撑点数量对构件变形的影响;依据两点支撑的优势设计,研制了新型调焦机构,并进行了力学环境试验验证和指向精度的测试。试验和测试结果表明:该调焦机构三个方向的一阶基频大于220 Hz,试验前后焦面指向精度优于2″。该调焦机构抗力学性能强、指向精度高、运行平稳、可靠性高,适用于空间遥感相机大尺寸长焦面的支撑与精密调整。

  12. Large displacement bi-directional out-of-plane Lorentz actuator array for surface manipulation

    Science.gov (United States)

    Park, Byoungyoul; Afsharipour, Elnaz; Chrusch, Dwayne; Shafai, Cyrus; Andersen, David; Burley, Greg

    2017-08-01

    This paper presents a large displacement out-of-plane Lorentz actuator array for surface manipulation. Actuators are formed from single crystal silicon flexible serpentine springs on either side of a rigid crossbar containing a narrow contact pillar. A rigid mounting rail system was employed to enable a 5  ×  5 array, which offers scalability of the array size. Analytical and finite element models were used to optimize actuator design. Individual actuators were tested to show linear deflection response of  ±150 µm motion, using a  ±14.7 mA current in the presence of a 0.48 T magnetic field. This actuator array is suitable for various 2D surface modification applications due to its large deformation with low current and temperature of operation, and narrow contact area to a target surface.

  13. 128×128InSb探测器结构模型研究%Structural modeling of 128 × 128 InSb focal plane array detector

    Institute of Scientific and Technical Information of China (English)

    孟庆端; 张晓玲; 张立文; 吕衍秋

    2012-01-01

    热冲击下红外焦平面探测器的高碎裂概率制约着其成品率.为明晰碎裂机理,基于等效设想,利用小面阵等效大面阵解决了128×128面阵探测器三维结构建模所需单元数过多的问题,同时综合考虑材料线膨胀系数的温度依赖性、材料强度的各向异性、表面加工损伤效应,合理选取InSb材料性能参数,建立起128×128面阵探测器结构有限元分析模型.模拟结果表明:热冲击下最大Von Mises应力值出现在N电极区域,其极值呈非连续分布,这意味着热冲击下128×128面阵探测器的裂纹起源于N电极区域,且不止一条.上述结论与碎裂统计分析报告中典型裂纹起源地及裂纹分布这两方面相符合,这为后续面阵探测器碎裂诱因的研究及结构可靠性设计提供了切实可行的研究思路.%Higher fracture probability appearing in InSb infrared focal plane array (IRFPA) subjected to thermal shock test, restricts its final yield. In order to understand the fracture mechanism, in light of the proposed equivalent method, where a 32×32 array is employed to replace the real 128×128 array, to a three - dimensional structural model of IRFPA is developed by taking into account the temperature dependence of thermal expansion coefficient, anisotropic mechanical strength of InSb chip, damaging effects of the surface of the InSb chip, and a reduction of 90% the out-of-plane elastic modulus. Simulation results show that a maximum Von Mises stress appears in the N electrode zone in InSb chip, and the extremum values present a non-continuous distribution. This means that the cracks is most likely to emerge in the region of N electrode, besides, the number of crack tracks is more than one. These are well consistent with the 128×128 InSb IRFPA fracture statistics results under thermal shock test. All these are beneficial to the further study of fracture inducing factors and structural reliability design

  14. A Statistical Framework for Utilization of Simultaneous Pupil Plane and Focal Plane Telemetry for Exoplanet Imaging, Part II: The Science Camera Image as a Function of the Wavefront Sensor Field

    CERN Document Server

    Frazin, Richard A

    2016-01-01

    In an effort to transcend the limitations of differential imaging of exoplanets in the era of extremely large telescopes (ELTs), the first paper in this series established a rigorous, fully polarimetric framework for determining the science camera (SC) image given a turbulent wavefront and unknown aberrations in multiple planes the optical system. This article builds on the structure developed in Paper I in order to rigorously express the polarimetric SC image in terms of the field impinging on the wavefront sensor (WFS), thereby providing a direct connection between the measurements made in both subsystems. This formulation allows the SC image to be written as a function of the WFS measurements, including the following unknown quantities which can, in principle, be estimated via statistical inference: the non-common path aberration (NCPA), WFS gain errors, aberrations downstream of the beamsplitter, and the planetary image. It is demonstrated that WFS bias error is mathematically equivalent to NCPA. Thus, wi...

  15. Explicit Computations of Instantons and Large Deviations in Beta-Plane Turbulence

    Science.gov (United States)

    Laurie, J.; Bouchet, F.; Zaboronski, O.

    2012-12-01

    We use a path integral formalism and instanton theory in order to make explicit analytical predictions about large deviations and rare events in beta-plane turbulence. The path integral formalism is a concise way to get large deviation results in dynamical systems forced by random noise. In the most simple cases, it leads to the same results as the Freidlin-Wentzell theory, but it has a wider range of applicability. This approach is however usually extremely limited, due to the complexity of the theoretical problems. As a consequence it provides explicit results in a fairly limited number of models, often extremely simple ones with only a few degrees of freedom. Few exception exist outside the realm of equilibrium statistical physics. We will show that the barotropic model of beta-plane turbulence is one of these non-equilibrium exceptions. We describe sets of explicit solutions to the instanton equation, and precise derivations of the action functional (or large deviation rate function). The reason why such exact computations are possible is related to the existence of hidden symmetries and conservation laws for the instanton dynamics. We outline several applications of this apporach. For instance, we compute explicitly the very low probability to observe flows with an energy much larger or smaller than the typical one. Moreover, we consider regimes for which the system has multiple attractors (corresponding to different numbers of alternating jets), and discuss the computation of transition probabilities between two such attractors. These extremely rare events are of the utmost importance as the dynamics undergo qualitative macroscopic changes during such transitions.

  16. Implicit large eddy simulation of unsteady cloud cavitation around a plane- convex hydrofoil

    Institute of Scientific and Technical Information of China (English)

    罗先武; 季斌

    2015-01-01

    The present paper focuses on the erosive cavitation behavior around a plane convex hydrofoil. The Zwart-Gerber-Belamri cavitation model is implemented in a library form to be used with the OpenFOAM. The implicit large eddy simulation (ILES) is app- lied to analyze the three dimensional unsteady cavitating flow around a plane convex hydrofoil. The numerical results in the cases under the hydrodynamic-conditions, which were experimentally tested at the high speed cavitation tunnel of the École Polytechnique Fédérale de Lausanne (EPFL), clearly show the sheet cavitation development, the shedding and the collapse of vapor clouds. It is noted that the cavitation evolutions including the maximum vapor length, the detachment and the oscillation frequency, are captured fairly well. Furthermore, the pressure pulses due to the cavitation development as well as the complex vortex structures are reasona- bly well predicted. Consequently, it may be concluded that the present numerical method can be used to investigate the unsteady cavitation around hydrofoils with a satisfactory accuracy.

  17. Large positive in-plane magnetoresistance induced by localized states at nanodomain boundaries in graphene

    Science.gov (United States)

    Wu, Han-Chun; Chaika, Alexander N.; Hsu, Ming-Chien; Huang, Tsung-Wei; Abid, Mourad; Abid, Mohamed; Aristov, Victor Yu; Molodtsova, Olga V.; Babenkov, Sergey V.; Niu, Yuran; Murphy, Barry E.; Krasnikov, Sergey A.; Lübben, Olaf; Liu, Huajun; Chun, Byong Sun; Janabi, Yahya T.; Molotkov, Sergei N.; Shvets, Igor V.; Lichtenstein, Alexander I.; Katsnelson, Mikhail I.; Chang, Ching-Ray

    2017-02-01

    Graphene supports long spin lifetimes and long diffusion lengths at room temperature, making it highly promising for spintronics. However, making graphene magnetic remains a principal challenge despite the many proposed solutions. Among these, graphene with zig-zag edges and ripples are the most promising candidates, as zig-zag edges are predicted to host spin-polarized electronic states, and spin-orbit coupling can be induced by ripples. Here we investigate the magnetoresistance of graphene grown on technologically relevant SiC/Si(001) wafers, where inherent nanodomain boundaries sandwich zig-zag structures between adjacent ripples of large curvature. Localized states at the nanodomain boundaries result in an unprecedented positive in-plane magnetoresistance with a strong temperature dependence. Our work may offer a tantalizing way to add the spin degree of freedom to graphene.

  18. A novel shape memory alloy microactuator for large in-plane strokes and forces

    Science.gov (United States)

    Kabla, M.; Ben-David, E.; Shilo, D.

    2016-07-01

    This paper describes a novel concept for in-plane actuators based on a thin free-standing shape memory alloy (SMA) film. The presented guidelines can be used to design a variety of actuators that can provide a combination of large strokes and forces for linear and rotary motions. A prototype actuator demonstrated a displacement of 45 μm related to 4.5% of the SMA film length, and a force of up to 115 mN related to a stress of 230 MPa in the SMA film without plastic deformations. These capabilities allow the actuator to work against the stiff springs that are essential for the devices’ ability to sustain vibrations, impacts, and accelerations.

  19. Interface Lattice Engineering of Si Composite Wafers for Large-Format HgCdTe Infrared Focal Plane Arrays

    Science.gov (United States)

    2012-08-07

    sessile dislocation. Examples of such sessile dislocation coalescence are the Lomer lock a 2 [011̄] + a 2 [101] → a 2 [110], (2.22) or a Lomer-Cottrell...Hg droplets condensing on to the layer. This will leave concentric circular marks where the Hg drop forms and evaporates away as seen in figure 5.2(d...sake, also assume that bα+ bβ = bsessile, where the result is a sessile dislocation. Finally, stipulate that when is near a side wall, α dislocations

  20. Changes in Joint Contact Mechanics in a Large Quadrupedal Animal Model After Partial Meniscectomy and a Focal Cartilage Injury.

    Science.gov (United States)

    Heckelsmiller, David J; James Rudert, M; Baer, Thomas E; Pedersen, Douglas R; Fredericks, Douglas C; Goetz, Jessica E

    2017-05-01

    Acute mechanical damage and the resulting joint contact abnormalities are central to the initiation and progression of post-traumatic osteoarthritis (PTOA). Study of PTOA is typically performed in vivo with replicate animals using artificially induced injury features. The goal of this work was to measure changes in a joint contact stress in the knee of a large quadruped after creation of a clinically realistic overload injury and a focal cartilage defect. Whole-joint overload was achieved by excising a 5-mm wedge of the anterior medial meniscus. Focal cartilage defects were created using a custom pneumatic impact gun specifically developed and mechanically characterized for this work. To evaluate the effect of these injuries on joint contact mechanics, Tekscan (Tekscan, Inc., South Boston, MA) measurements were obtained pre-operatively, postmeniscectomy, and postimpact (1.2-J) in a nonrandomized group of axially loaded cadaveric sheep knees. Postmeniscectomy, peak contact stress in the medial compartment is increased by 71% (p = 0.03) and contact area is decreased by 35% (p = 0.001); the center of pressure (CoP) shifted toward the cruciate ligaments in both the medial (p = 0.004) and lateral (p = 0.03) compartments. The creation of a cartilage defect did not significantly change any aspect of contact mechanics measured in the meniscectomized knee. This work characterizes the mechanical environment present in a quadrupedal animal knee joint after two methods to reproducibly induce joint injury features that lead to PTOA.

  1. 应用于红外成像导引头的非制冷焦平面探测器%Uncooled Focal Plane Arrays Detector Applied for Infrared Imaging Seeker

    Institute of Scientific and Technical Information of China (English)

    李煜; 白丕绩; 陶禹; 袁名松

    2016-01-01

    With great progress in fabrication technology, medium(large)scale, high temperature response and small pixel pitch UFPAs(Uncooled Focal Plane Arrays)detectors are produced. For its high cost-effectiveness, compactness and easy maintenance etc, seeker using UFPAs detector has become an important member in the infrared imaging seeker family. Some kinds of domestic and foreign representative weapons such as anti-tank missile, precision attack missile, precision guided bomb, anti-ship missile etc. and specifications of UFPAs used in infrared imaging guidance systems are introduced in detail. Finally, the characteristics and development trend of UFPAs for uncooled infrared imaging guidance systems are summarized.%随着非制冷探测器技术的迅猛发展,中大规模、高灵敏度的非制冷焦平面器件实现工程化应用.使用非制冷焦平面器件的红外成像导引头具有效费比高、结构紧凑、易维护等优点,已成为红外成像导引头的重要成员之一.介绍了国内外几款采用非制冷红外成像导引头的反坦克导弹、精确攻击导弹、精确炸弹、反舰导弹,以及所使用的非制冷焦平面器件的性能参数,总结了用于红外成像制导系统的非制冷焦平面器件的特点及发展趋势.

  2. Research on an FM/cw ladar system using a 64 × 64 InGaAs metal-semiconductor-metal self-mixing focal plane array of detectors.

    Science.gov (United States)

    Gao, Jian; Sun, Jianfeng; Cong, Mingyu

    2017-04-01

    Frequency-modulated/continuous-wave imaging systems are a focal plane array (FPA) ladar architecture that is applicable to smart munitions, reconnaissance, face recognition, robotic navigation, etc. In this paper, we report a 64×64 pixel FPA ladar system we built using a 1550 nm amplified laser diode transmitter and an InAlAs/InGaAs metal-semiconductor-metal self-mixing detector array and the test results attained over the years it was constructed. Finally, we gained 4D imaging (3D range + 1D intensity) of the target with the range of 220 m.

  3. 15-{micro}m 128 x 128 GaAs/Al{sub x}Ga{sub 1{minus}x}As quantum well infrared photodetector focal plane array camera

    Energy Technology Data Exchange (ETDEWEB)

    Gunapala, S.D.; Park, J.S.; Sarusi, G.; Lin, T.L.; Liu, J.K.; Maker, P.D.; Muller, R.E. [Jet Propulsion Lab., Pasadena, CA (United States); Shott, C.A.; Hoelter, T. [Amber, Goleta, CA (United States)

    1997-01-01

    In this paper, the authors discuss the development of very sensitive, very long wavelength infrared GaAs/Al{sub x}Ga{sub 1{minus}x}As quantum well infrared photodetectors (QWIP`s) based on bound-to-quasi-bound intersubband transition, fabrication of random reflectors for efficient light coupling, and the demonstration of a 15-{micro}m cutoff 128 x 128 focal plane array imaging camera. Excellent imagery, with a noise equivalent differential temperature (NE{Delta}T) of 30 mK has been achieved.

  4. COSIGN – developing an optical software controlled data plane for future large-scale datacenter networks

    DEFF Research Database (Denmark)

    Galili, Michael; Kamchevska, Valerija; Fagertun, Anna Manolova;

    2015-01-01

    This talk will present the work of the EU project COSIGN targeting the development of optical data plane solutions for future high-capacity datacenter networks (DCNs). Optical data planes with high capacity and high flexibility through software control are developed in order to enable a coherent...

  5. 基于焦平面归一化响应特性的红外非均匀性校正%Nonuniformity Correction Based on Unified Photoresponse Characteristics of Infrared Focal Plane Arrays

    Institute of Scientific and Technical Information of China (English)

    左超; 陈钱; 顾国华

    2011-01-01

    The nonuniformity in the infrared focal plane array limits the quality of infrared imaging system. A new nonuniformity correction procedure based on the unified photoresponse characteristics of infrared focal plane arrays and the correction ratio based on the chi-square histogram were presented. The correction output of each detector took both its observed value and the average response of the focal plane array into account. The correction parameters were obtained by establishing the relationship between the difference of the observed value and its ideal response and the average response of the focal plane array. The proposed correction ratio took into account of both spatial and temporal response characteristics of focal plane arrays, thus it gave more reasonable results on the measurement of the degree of nonuniformity. Experimental results show that its performance is better than that of the two-point correction and the quadratic curve fitting correction using the input values, and has excellent correction capability to the pixels with abnormal responses. In addition, the algorithm has the advantages of high correction precision, less correction factors and easy to real-time processing, which enhances its utility value.%红外焦平面阵列的非均匀性噪音是制约红外成像质量的主要因素,非均匀性校正是红外焦平面器件应用的一个关键技术.本文提出了一种基于焦平面归一化响应特性且易于实现的非均匀性校正算法,并基于像元分布的卡方直方图提出一种新的图像非均匀性评估方法,即校正比例.该方法的校正输出考虑了每个像元的观测值与焦平面的响应信号的平均值,校正参量通过将像元的输出与其理想校正结果之间的偏差用焦平面响应的平均值建立联系而计算得到.提出的校正比例兼顾考虑了焦平面响应的时间与空间特性,比现有的图像非均匀性评估方法更能合理衡量焦

  6. Large-sized out-of-plane stretchable electrodes based on poly-dimethylsiloxane substrate

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Namsun [School of Mechatronics, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Lee, Jongho [School of Mechatronics, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Research Institute for Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Kim, Sohee, E-mail: soheekim@gist.ac.kr [School of Mechatronics, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Department of Medical System Engineering (DMSE), Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of)

    2014-12-15

    This paper describes a reliable fabrication method of stretchable electrodes based on poly-dimethylsiloxane (PDMS) substrate. The electrode traces and pads were formed in out-of-plane structures to improve the flexibility and stretchability of the electrode array. The suspended traces and pads were attached to the PDMS substrate via parylene posts that were located nearby the traces and under the pads. As only conventional micro-electro-mechanical systems techniques were used, the out-of-plane electrode arrays were clearly fabricated at wafer level with high yield and reliability. Also, bi-layer out-of-plane electrodes were formed through additional fabrication steps in addition to mono-layer out-of-plane electrodes. The mechanical characteristics such as the stretchability, flexibility, and foldability of the fabricated electrodes were evaluated, resulting in stable electrical connection of the metal traces with up to 32.4% strain and up to 360° twist angle over 25 mm. The durability in stretched condition was validated by cyclic stretch test with 10% and 20% strain, resulting in electrical disconnection at 8600 cycles when subjected to 20% strain. From these results, it is concluded that the proposed fabrication method produced highly reliable, out-of-plane and stretchable electrodes, which would be used in various flexible and stretchable electronics applications.

  7. 基于衬底温度的红外焦平面联合非均匀性校正%Combined nonuniformity correction algorithm of infrared focal plane arrays based on substrate temperature

    Institute of Scientific and Technical Information of China (English)

    唐艳秋; 孙强; 赵建; 姚凯男

    2016-01-01

    The advantages and disadvantages in nonuniformity correction (NUC) algorithms based on calibration and scene of infrared focal plane arrays(IRFPA) were analysed separately. The combined NUC algorithm was presented. The thermal imaging system extracted the gain and offset factor from the FLASH which storged beforehand according to the substrate temperature of the IRFPA at the moment of power on. These factor was adopted to remove the nonuniformity of the detector simply. Based on the analysis of the characteristic of residual noise after initial correction, the P-M filter was used to replace the linear spatial average filter in the Neural Network nonuniformity correction algorithm (NN-NUC), which could preserve the image edge. Experimental results show that the proposed algorithm can accelerate the rate of convergence, reduces the correction error largely, and avoids the image degradation caused by the response drift of IRFPA.%分别分析了红外焦平面阵列(IRFPA)基于定标的非均匀性校正法(NUC)和基于场景的NUC算法各自的优势和问题,在此基础上提出了联合非均匀性校正方法。根据上电时刻焦平面衬底的温度值,从FLASH中提取事先存储的对应温度区间的增益和偏置校正参数,初步消除探测器的非均匀性。通过分析初步校正后图像残余非均匀性噪声的特性,提出了用具有保边缘特性的P-M滤波取代传统神经网络算法中的四邻域均值滤波来获得期望图像,从而减小了图像边缘误差。实验结果表明,该算法收敛速度快,校正精度高,有效避免了因红外焦平面响应特性漂移而引起的图像降质。

  8. 二极管原理非制冷红外焦平面阵列的集成设计%Integration of uncooled diode infrared focal plane array

    Institute of Scientific and Technical Information of China (English)

    王玮冰; 陈大鹏; 明安杰; 欧文; 刘战峰

    2011-01-01

    The design and fabrication of uncooled diode infrared focal plane array (FPA) have been developed for the applications of low cost and high performance uncooled infrared imaging technology. The design and integration of FPA and readout integrated circuit(ROIC), as well as the process integration of CMOS and MEMS are the important parts in the research and development of uncooled diode infrared FPA. Silicon on insulator (SOI) diode FPA takes great advantage of standard CMOS process for large scale array implementation and integration. The design of ROIC was based on standard CMOS process. 320x240 diode FPA was fabricated with both of CMOS and MEMS processes, and finally tested with the temperature coefficient of around -1.5 mV/K for diode forward voltage at a constant current bias. Analysis and experiments prove the high feasibility of the design and manufacture of uncooled diode FPA which is a low cost infrared technology in the wide field.%面向非制冷红外成像的低成本高性能应用,二极管原理的红外焦平面阵列的设计和工艺实现得到研究和发展.焦平面和读出电路的设计集成以及CMOS和MEMS工艺集成是此项技术的研究重点.基于SOI的二极管原理焦平面阵列在低成本的利用CMOS工艺实现大规模阵列集成方面有很大的优势.读出电路是基于标准CMOS工艺进行设计的.320×240规模的焦平面阵列利用CMOS标准工艺和MEMS工艺集成已经得到了结构实验结果.研究并测得二极管像元的正向压降的温度变化率约为-1.5mV/K.分析和实验证明了二极管原理非制冷红外焦平面阵列的设计和工艺可行性,是一项可以低成本广泛应用的红外成像技术.

  9. PTAS for k-tour cover problem on the plane for moderately large values of k

    DEFF Research Database (Denmark)

    Adamaszek, Anna; Czumaj, Artur; Lingas, Andrzej

    2009-01-01

    Let P be a set of n points in the Euclidean plane and let O be the origin point in the plane. In the k-tour cover problem (called frequently the capacitated vehicle routing problem), the goal is to minimize the total length of tours that cover all points in P, such that each tour starts and ends...... in O and covers at most k points from P. The k-tour cover problem is known to be NP-hard. It is also known to admit constant factor approximation algorithms for all values of k and even a polynomial-time approximation scheme (PTAS) for small values of k, i.e., k=O(log n / log log n). We significantly...

  10. Radiation of de-excited electrons at large times in a strong electromagnetic plane wave

    CERN Document Server

    Kazinski, P O

    2013-01-01

    The late time asymptotics of the physical solutions to the Lorentz-Dirac equation in the electromagnetic external fields of simple configurations -- the constant homogeneous field, the linearly polarized plane wave (in particular, the constant uniform crossed field), and the circularly polarized plane wave -- are found. The solutions to the Landau-Lifshitz equation for the external electromagnetic fields admitting a two-parametric symmetry group, which include as a particular case the above mentioned field configurations, are obtained. General properties of the total radiation power of a charged particle are established. In particular, for a circularly polarized wave and constant uniform crossed fields, the total radiation power in the asymptotic regime is independent of the charge and the external field strength, when expressed in terms of the proper-time, and equals a half of the rest energy of a charged particle divided by its proper-time. The spectral densities of the radiation power formed on the late ti...

  11. Characterization of the large area plane-symmetric low-pressure DC glow discharge

    Science.gov (United States)

    Avtaeva, S.; Gorokhovsky, V.; Myers, S.; Robertson, S.; Shunko, E.; Zembower, Z.

    2016-10-01

    Electron density and temperature as well as nitrogen dissociation degree in the low-pressure (10-50 mTorr) large area plane-symmetric DC glow discharge in Ar-N2 mixtures are studied by probes and spectral methods. Electron density measured by a hairpin probe is in good agreement with that derived from the intensity ratio of the N2 2nd positive system bands IC , 1 - 3/IC , 0 - 2 and from the intensity ratio of argon ions and atom lines IArII/IArI, while Langmuir probe data provides slightly higher values of electron density. Electron density in the low-pressure DC glow discharge varies with the discharge conditions in the limits of 108-1010 cm- 3. The concept of electron temperature can be used in low-pressure glow discharges with reservations. The intensity ratio of (0-0) vibrational bands of N2 1st negative and 2nd positive systems I391.4/I337.1 exhibits the electron temperature of 1.5-2.5 eV when argon fraction in the mixture is higher than nitrogen fraction and this ratio quickly increases with nitrogen fraction up to 10 eV in pure nitrogen. The electron temperature calculated from Langmuir probe I-V characteristics assuming a Maxwellian EEDF, gives Te 0.3-0.4 eV. In-depth analysis of the EEDF using the second derivative of Langmuir probe I-V characteristics shows that in a low-pressure glow discharge the EEDF is non-Maxwellian. The EEDF has two populations of electrons: the main background non-Maxwellian population of ;cold; electrons with the mean electron energy of 0.3-0.4 eV and the small Maxwellian population of ;hot; electrons with the mean electron energy of 1.0-2.5 eV. Estimations show that with electron temperature lower than 1 eV the rate of the direct electron impact ionization of N2 is low and the main mechanism of N2 ionization becomes most likely Penning and associative ionization. In this case, assumptions of the intensity ratio IN2+ , 391/IN2 , 337 method are violated. In the glow discharge, N2 dissociation degree reaches about 7% with the argon

  12. "Short-term time prediction" of large EQs by the use of "Large Scale Piezoelectricity" generated by the focal areas loaded with excess stress load

    CERN Document Server

    Thanassoulas, C

    2008-01-01

    In this work, it is demonstrated that the Earth's preseismic electric field, which is registered by a pair of electrodes in contact to the ground surface at certain distance from the epicentral area, corresponds to the gradient of the total field generated in the focal area as a function of time and distance from it. The original form of the generated preseismic field follows closely the theoretical piezoelectric potential form. The later is obtained after integration in time of the original registered potential grad data values. Consequently, the time of occurrence of the imminent earthquake (collapsing of the rock formation) is estimated by the classical laws of rock fracturing based on theoretical Rock Mechanics. The methodology has been tested on the grad potential data, registered in Greece, before four large EQs which took place in the regional area as follows: Izmit, Turkey EQ (M = 7.8R, 17th August, 1999), Milos, Greece EQ (M = 5.6R, 21st May, 2002), Kythira Greece EQ (M = 6.9R, 8th January, 2006) and...

  13. Radiation of de-excited electrons at large times in a strong electromagnetic plane wave

    Science.gov (United States)

    Kazinski, P. O.

    2013-12-01

    The late time asymptotics of the physical solutions to the Lorentz-Dirac equation in the electromagnetic external fields of simple configurations-the constant homogeneous field, the linearly polarized plane wave (in particular, the constant uniform crossed field), and the circularly polarized plane wave-are found. The solutions to the Landau-Lifshitz equation for the external electromagnetic fields admitting a two-parametric symmetry group, which include as a particular case the above mentioned field configurations, are obtained. Some general properties of the total radiation power of a charged particle are established. In particular, for a circularly polarized wave and constant uniform crossed fields, the total radiation power in the asymptotic regime is independent of the charge and the external field strength, when expressed in terms of the proper-time, and equals a half the rest energy of a charged particle divided by its proper-time. The spectral densities of the radiation power formed on the late time asymptotics are derived for a charged particle moving in the external electromagnetic fields of the simple configurations pointed above. This provides a simple method to verify experimentally that the charged particle has reached the asymptotic regime.

  14. Pupil plane optimization for single-mode multiaxial optical interferometry with a large number of telescopes

    CERN Document Server

    Le Bouquin, J B; Bouquin, Jean-Baptiste Le; Tatulli, Eric

    2006-01-01

    Incoming optical interferometers will allow spectro-imaging at high angular resolution. Non-homothetic Fizeau concept combines good sensitivity and high spectral resolution capabilities. However, one critical issue is the design of the beam recombination scheme, at the heart of the instrument. We tackle the possibility of reducing the number of pixels that are coding the fringes by compressing the pupil plane. Shrinking the number of pixels -- which drastically increases with the number of recombined telescopes -- is indeed a key issue that enables to reach higher limiting magnitude, but also allows to lower the required spectral resolution and fasten the fringes reading process. By means of numerical simulations, we study the performances of existing estimators of the visibility with respect to the compression process. We show that, not only the model based estimator lead to better signal to noise ratio (SNR) performances than the Fourier ones, but above all it is the only one which prevent from introducing ...

  15. Radiation of de-excited electrons at large times in a strong electromagnetic plane wave

    Energy Technology Data Exchange (ETDEWEB)

    Kazinski, P.O., E-mail: kpo@phys.tsu.ru

    2013-12-15

    The late time asymptotics of the physical solutions to the Lorentz–Dirac equation in the electromagnetic external fields of simple configurations–the constant homogeneous field, the linearly polarized plane wave (in particular, the constant uniform crossed field), and the circularly polarized plane wave–are found. The solutions to the Landau–Lifshitz equation for the external electromagnetic fields admitting a two-parametric symmetry group, which include as a particular case the above mentioned field configurations, are obtained. Some general properties of the total radiation power of a charged particle are established. In particular, for a circularly polarized wave and constant uniform crossed fields, the total radiation power in the asymptotic regime is independent of the charge and the external field strength, when expressed in terms of the proper-time, and equals a half the rest energy of a charged particle divided by its proper-time. The spectral densities of the radiation power formed on the late time asymptotics are derived for a charged particle moving in the external electromagnetic fields of the simple configurations pointed above. This provides a simple method to verify experimentally that the charged particle has reached the asymptotic regime. -- Highlights: •Late time asymptotics of the solutions to the Lorentz–Dirac equation are studied. •General properties of the total radiation power of electrons are established. •The total radiation power equals a half the rest energy divided by the proper-time. •Spectral densities of radiation formed on the late time asymptotics are derived. •Possible experimental verification of the results is proposed.

  16. 高帧频低噪声红外焦平面信息获取系统%Information Acquisition System for Thermal Infrared Focal Plane Array with High Frame-rate and Low-noise

    Institute of Scientific and Technical Information of China (English)

    程高超; 陈小文; 王湘波; 李春来; 王建宇

    2013-01-01

    A kind of high-rate and low-noise information acquisition system for French cooled 320×256 HgCdTe long wave infrared focal plane arrays MARS LW K508 was designed. The system consists of detector drive, signal processing, data acquisition and sequential control, image transmission and processing modules. Experimental results show that the frame frequency of the system can be up to 200 frame/s, the RMS is 0.7-0.8 mV (300 K) and images after nonuniformity correction are clear, which can be used in the high-end thermal infrared focal plane field such as surface thermal infrared spectral detection and high-speed infrared surveillance and imaging.%  设计了一种针对法国引进制冷型高性能320×256元HgCdTe长波红外焦平面探测器MARS LW K508的信息获取系统。该系统包括红外光学镜头、探测器驱动电路、信号处理电路、数据采集与控制电路、图像传输与处理软件等。经过测试,系统在全帧读出时可实现最高200 Hz的帧频,面对300 K黑体目标测试得到均值噪声为0.7~0.8 mV,综合灵敏度优于0.1 K。系统获取的图像经过校正后质量良好。该系统可用于地表热红外成像光谱探测、高速红外监视成像等高端热红外焦平面应用领域。

  17. INFLUENCE OF LARGE-SCALE VORTICAL STRUCTURES ON THE PARTICLE DISPERSION IN A PLANE MIXING LAYER

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The present study considers the developing mixing layer that is formed by merging of two free streams initially separated by a splitter plate. To investigate the influence of the vortical structures on the particle dispersion, numerical simulation was conducted when the velocity ratio, defined as R=(U∞-U-∞)/(U∞+U-∞), is 0.5. Large-Eddy Simulation (LES) was employed to understand the effect of large-scale vortical structures originated by the Kelvin-Helmholtz instability on the partical dispersion. The flyash with the particle sizes 10, 50, 100, 150, and 200μm respectively were loaded at the origin of the two-dimensional mixing layer. It is confirmed that the particle dispersion depends strongly on the motion of large-scale vortical structures. The particle dispersion is visualized numerically by following the particle trajectories in the mixing layer undergoing pairing interaction.

  18. Measuring the (d, sup 2 He) reaction with the focal-plane detection system of the BBS magnetic spectrometer at AGOR

    CERN Document Server

    Rakers, S; Bassini, R; Baeumer, C; Berg, A M; Frekers, D; De Frenne, D; Hagemann, M; Hannen, V M; Harakeh, M N; Hartig, M; Henderson, R; Heyse, J; Huu, M A D; Jacobs, E; Mielke, M; Schippers, J M; Schmidt, R; Werf, S Y; Wörtche, H J

    2002-01-01

    At intermediate energies, the (d, sup 2 He) charge-exchange reaction can be used to observe Gamow-Teller strength in the beta sup + direction. sup 2 He denotes the two-proton system being in the singlet sup 1 S sub 0 state. In the present experiment the two protons, which in the laboratory frame are emitted into the forward direction, have been momentum analyzed and detected in coincidence by the same spectrometer and detector. Protons from deuteron breakup processes can induce a large accidental coincidence background because of the much larger breakup cross-section as compared to the (d, sup 2 He) cross-section. Nevertheless, background-free sup 2 He spectra with a resolution of 145 keV at an incident energy of 170 MeV are obtained, allowing the identification of many levels with high precision in the residual nuclei. The essential features of the detection system and the data-acquisition and analysis techniques which make our (d, sup 2 He) experiments possible are described. Two nuclei, sup 1 sup 2 C and s...

  19. A priori tests of large Eddy simulation of the compressible plane mixing layer

    NARCIS (Netherlands)

    Vreman, A.W.; Geurts, Bernardus J.; Kuerten, Johannes G.M.

    1995-01-01

    Three important aspects for the assessment of the possibilities of Large Eddy Simulation (LES) of compressible flow are investigated. In particular the magnitude of all subgrid-terms, the role of the discretization errors and the correlation of the turbulent stress tensor with several subgrid-models

  20. A priori tests of large eddy simulation of the compressible plane mixing layer

    NARCIS (Netherlands)

    Vreman, Bert; Geurts, Bernard; Kuerten, Hans

    1995-01-01

    Three important aspects for the assessment of the possibilities of Large Eddy Simulation (LES) of compressible flow are investigated. In particular the magnitude of all subgrid-terms, the role of the discretization errors and the correlation of the turbulent stress tensor with several subgrid-models

  1. Thermal Design of Focal Plane Assembly on Space-borne Camera Based on Thermo-Electric Cooling Technology%基于热电制冷技术的某星载相机焦面组件热设计

    Institute of Scientific and Technical Information of China (English)

    连新昊; 颜吟雪

    2011-01-01

    热电制冷(Thermo-Electric Cooling,TEC)技术是利用帕尔帖效应的一种制冷方法,它不需要任何工质,无活动部件,结构简单,非常适宜于微型制冷领域或有特殊要求的场合.文章将TEC技术应用于某星载相机焦面组件的热设计,解决了探测器恒温控制问题.仿真分析结果表明,基于TEC技术的热设计方案在满足探测器恒温控制的同时,控温功耗比传统方案降低了90%.%Thermo-Electric Cooling (TEC) technology, based on Peltier effect, is one of the refrigeration methods. In view of the advantages of TEC, such as simple structure, no refrigerant, no moving parts, it is particularly suitable for micro-refrigeration or other special occasions. TEC technology, which is applied in thermal design of focal plane assembly on space-borne camera, solved the problem that how to keep sensor's temperature constant The simulation results showed that thermal design based on TEC technology could keep sensor's temperature constant, and meanwhile, its power used for controlling temperature reduced by 90% compared with traditional thermal design.

  2. Distributed calculation method for large-pixel-number holograms by decomposition of object and hologram planes.

    Science.gov (United States)

    Jackin, Boaz Jessie; Miyata, Hiroaki; Ohkawa, Takeshi; Ootsu, Kanemitsu; Yokota, Takashi; Hayasaki, Yoshio; Yatagai, Toyohiko; Baba, Takanobu

    2014-12-15

    A method has been proposed to reduce the communication overhead in computer-generated hologram (CGH) calculations on parallel and distributed computing devices. The method uses the shifting property of Fourier transform to decompose calculations, thereby avoiding data dependency and communication. This enables the full potential of parallel and distributed computing devices. The proposed method is verified by simulation and optical experiments and can achieve a 20 times speed improvement compared to conventional methods, while using large data sizes.

  3. Effect of small in-plane anisotropy in the large-D phase systems based on Ni{sup 2+} (S=1) ions in Heisenberg antiferromagnetic chains

    Energy Technology Data Exchange (ETDEWEB)

    Rudowicz, Czesław, E-mail: crudowicz@zut.edu.pl

    2014-03-01

    Heisenberg antiferromagnetic chains based on Ni{sup 2+} ions with integer spin S=1 exhibit intriguing behavior, e.g. the Haldane gap phase and the large-D phase. The predicted transitions between the two phases and the Neel phase has generated search for real candidate systems. Crucial to this search is the interplay between the ‘in-plane anisotropy’, i.e. the rhombic zero-field splitting (ZFS) E-term, and the ‘planar anisotropy’, i.e. the axial ZFS D-term. This paper clarifies intricate properties of orthorhombic ZFS Hamiltonians (H{sub ZFS}) and inconsistencies revealed by critical survey of pertinent studies. Reporting the non-standard (D, E) sets with λ=E/D out of the standard range (0, 1/3) alongside the standard sets with λ∝(0, 1/3) indicates that these properties are not recognized. We show that direct comparisons of the non-standard and standard sets are meaningless and lead to incorrect conclusions on the strength of the ‘in-plane anisotropy’ (E) as compared with the ‘planar anisotropy’ (D). To remedy such problems, the ZFSP sets reported for the large-D phase candidate systems are reanalyzed using orthorhombic standardization. The six physically equivalent ZFSP sets are determined in the conventional (D, E) and Stevens (b{sub 2}{sup 0}, b{sub 2}{sup 2}) notation. These considerations help understanding intricacies inherent in orthorhombic H{sub ZFS} and provide consistent data for future modeling of ZFS parameters in the large-D phase and Haldane gap systems.

  4. Precision Laser Annealing of Focal Plane Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Bender, Daniel A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); DeRose, Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Starbuck, Andrew Lea [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Verley, Jason C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jenkins, Mark W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    We present results from laser annealing experiments in Si using a passively Q-switched Nd:YAG microlaser. Exposure with laser at fluence values above the damage threshold of commercially available photodiodes results in electrical damage (as measured by an increase in photodiode dark current). We show that increasing the laser fluence to values in excess of the damage threshold can result in annealing of a damage site and a reduction in detector dark current by as much as 100x in some cases. A still further increase in fluence results in irreparable damage. Thus we demonstrate the presence of a laser annealing window over which performance of damaged detectors can be at least partially reconstituted. Moreover dark current reduction is observed over the entire operating range of the diode indicating that device performance has been improved for all values of reverse bias voltage. Additionally, we will present results of laser annealing in Si waveguides. By exposing a small (<10 um) length of a Si waveguide to an annealing laser pulse, the longitudinal phase of light acquired in propagating through the waveguide can be modified with high precision, <15 milliradian per laser pulse. Phase tuning by 180 degrees is exhibited with multiple exposures to one arm of a Mach-Zehnder interferometer at fluence values below the morphological damage threshold of an etched Si waveguide. No reduction in optical transmission at 1550 nm was found after 220 annealing laser shots. Modeling results for laser annealing in Si are also presented.

  5. Medical Applications of IR Focal Plane Arrays

    Science.gov (United States)

    2007-11-02

    imaging in deep venous thrombosis, coming up with definitive conclusions. Kunihiko Mabuchi (Japan) describes the development of an image processing... Hemodialysis Shunts", Proc. 19th Annual Intl. IEEE/EMBS Conf., Chicago, II., Nov. 1997. 60. Marcott, C, Reeder, R., Paschelis, E., Boskey, A., "FT-IR...major thrust for all the infrared measurements. These, coupled with standard equipment and methods will definitely give us the further validation

  6. Focal plane arrays for THz imaging

    NARCIS (Netherlands)

    Iacono, A.; Bencivenni, C.; Freni, A.; Neto, A.; Gerini, G.

    2012-01-01

    The growing attention for Terahertz technology finds support in the high number of applications which will benefit by its use. In the space science sector, the investigation of the THz frequency range will improve the knowledge of the universe, giving a clearer view on its origin and its evolution.

  7. Analysis of the Elastic Large Deflection Behavior for Metal Plates under Nonuniformly Distributed Lateral Pressure with In-Plane Loads

    Directory of Open Access Journals (Sweden)

    Jeom Kee Paik

    2012-01-01

    Full Text Available The Galerkin method is applied to analyze the elastic large deflection behavior of metal plates subject to a combination of in-plane loads such as biaxial loads, edge shear and biaxial inplane bending moments, and uniformly or nonuniformly distributed lateral pressure loads. The motive of the present study was initiated by the fact that metal plates of ships and ship-shaped offshore structures at sea are often subjected to non-uniformly distributed lateral pressure loads arising from cargo or water pressure, together with inplane axial loads or inplane bending moments, but the current practice of the maritime industry usually applies some simplified design methods assuming that the non-uniform pressure distribution in the plates can be replaced by an equivalence of uniform pressure distribution. Applied examples are presented, demonstrating that the current plate design methods of the maritime industry may be inappropriate when the non-uniformity of lateral pressure loads becomes more significant.

  8. Benchmarking of depth of field for large out-of-plane deformations with single camera digital image correlation

    Science.gov (United States)

    Van Mieghem, Bart; Ivens, Jan; Van Bael, Albert

    2017-04-01

    A problem that arises when performing stereo digital image correlation in applications with large out-of-plane displacements is that the images may become unfocused. This unfocusing could result in correlation instabilities or inaccuracies. When performing DIC measurements and expecting large out-of-plane displacements researchers either trust on their experience or use the equations from photography to estimate the parameters affecting the depth of field (DOF) of the camera. A limitation of the latter approach is that the definition of sharpness is a human defined parameter and that it does not reflect the performance of the digital image correlation system. To get a more representative DOF value for DIC applications, a standardised testing method is presented here, making use of real camera and lens combinations as well as actual image correlation results. The method is based on experimental single camera DIC measurements of a backwards moving target. Correlation results from focused and unfocused images are compared and a threshold value defines whether or not the correlation results are acceptable even if the images are (slightly) unfocused. By following the proposed approach, the complete DOF of a specific camera/lens combination as function of the aperture setting and distance from the camera to the target can be defined. The comparison between the theoretical and the experimental DOF results shows that the achievable DOF for DIC applications is larger than what theoretical calculations predict. Practically this means that the cameras can be positioned closer to the target than what is expected from the theoretical approach. This leads to a gain in resolution and measurement accuracy.

  9. 应用于非制冷焦平面器件上的PMN-PT铁电薄膜%PMN-PT Thin Film for Uncooled Infrared Focal Plane Array Applications

    Institute of Scientific and Technical Information of China (English)

    李振豪; 李琳; 普朝光

    2011-01-01

    利用射频磁控溅射方法生长掺钛铌镁酸铅-钛酸铅(lead magnesio-niobate titanate,PMN-PT)薄膜,研究PMN-PT薄膜的热处理技术,并测试制备的PMN-PT薄膜样品的晶向结构及电性能。结果表明:PMN-PT薄膜在450℃退火就能完全晶化成钙钛矿结构,其热释电系数达到0.9×10-8C/(cm2K),有望解决目前阻碍集成式铁电型非制冷焦平面探测器技术发展的瓶颈问题,即铁电薄膜晶化生长所需的高温与读出电路可承受温度的兼容性问题。%lead magnesio–niobate titanate(PMN–PT) ferroelectric thin films were prepared by radio-frequency magnetron sputtering.An annealing procedure for PMN–PT thin films with pre-annealing process was studied.After the annealing procedure was applied,performances of the thin films were investigated.Experimental results show that pre-annealing at 300 ℃ for 5 min followed by an-nealing at 450 ℃ for 5 min are enough for the perovskite formation of PMN–PT films.The test of samples performance with py-roelectric coefficients of 0.9 × 10–8 C/(cm2?K) for PMN–PT thin films indicates that the low annealing procedure might play an im-portant role in the development of monolithic ferroelectric uncooled focal plane arrays.

  10. 线性菲涅耳反射聚光器聚焦光斑能流密度分布的计算%Calculation of Flux Density Distribution on Focal Plane in Linear Fresnel Reflector

    Institute of Scientific and Technical Information of China (English)

    赵金龙; 李林; 崔正军; 陈洪晶; 熊勇刚; 马晓辉; 刘国军

    2012-01-01

    The spot flux-density distribution on the focal plane of linear Fresnel reflecting (LFR) concentrators is calculated with Matlab program by the ray-tracing method, with the shape of the sun, cosine loss, shading and blocking loss, taken into account in the process. Three-dimensional optical geometric model is established and the spot flux-density distribution is calculated with Matlab program. The model is demonstrated and justified by comparing simulation results of this Matlab program with that of SolTrace software developed by the U. S. National Renewable Energy Laboratory (NREL). The effects of different mirror shapes for LFR are also compared in order to obtain the higher efficiency of concentrator field.%利用光线追迹的方法,考虑太阳形状、余弦损失、阴影及遮挡损失的影响,建立线性菲涅耳反射(LFR)聚光器的三维光学几何模型,给出其光斑能流密度分布的计算式,采用Matlab软件编程实现该算法.将计算结果与美国国家可再生能源实验室(NREL)开发的SolTrace软件仿真结果相对比,光斑能流密度分布曲线基本吻合,证明了该算法的正确性.为了获得更高的镜场聚光效率,对比了不同反射镜面型对LFR聚光器的影响.

  11. Development and Testing of a Power Trough System Using a Structurally-Efficient, High-Performance, Large-Aperture Concentrator with Thin Glass Reflector and Focal Point Rotation

    Energy Technology Data Exchange (ETDEWEB)

    May, E. K.; Forristall, R.

    2005-11-01

    Industrial Solar Technology has assembled a team of experts to develop a large-aperture parabolic trough for the electric power market that moves beyond cost and operating limitations of 1980's designs based on sagged glass reflectors. IST's structurally efficient space frame design will require nearly 50% less material per square meter than a Solel LS-2 concentrator and the new trough will rotate around the focal point. This feature eliminates flexhoses that increase pump power, installation and maintenance costs. IST aims to deliver a concentrator module costing less than $100 per square meter that can produce temperatures up to 400 C. The IST concentrator is ideally suited for application of front surface film reflectors and ensures that US corporations will manufacture major components, except for the high temperature receivers.

  12. 基于PM扩散的红外焦平面阵列神经网络非均匀校正算法%Neural Network Non-uniformity Correction for Infrared Focal Plane Array Based on Perona Malik Diffusion

    Institute of Scientific and Technical Information of China (English)

    杨硕; 赵保军; 毛二可; 唐林波

    2013-01-01

    该文针对红外图像中含有非均匀性噪声和高斯噪声的退化模型,提出了一种基于各向异性(Perona Malik, PM)扩散的神经网络非均匀校正(PM-NN-NUC)算法。建立了关于非均匀校正的极小化模型。通过对新模型的最陡下降方程和偏微分方程的推导,可以看出PM-NN-NUC算法利用了神经网络校正和PM扩散在滤波过程中的相似性,不仅直接用于产生神经网络校正的期望值,还作用于计算迭代步长,而校正系数又反作用于PM的扩散过程,更好地将 PM 扩散和神经网络校正统一地结合在一起。通过对实际含噪红外图像进行实验,证明新模型可抑制非均匀噪声,并防止图像产生退化。%A new Neural Network Non-Uniformity Correction (PM-NN-NUC) algorithm is proposed for InfraRed Focal Plane Array (IRFPA) based on Perona Malik (PM) diffusion for the situation of degradation model both containing fix pattern noise and Gaussian noise in infrared image. A minimize model is established concerning Non-Uniformity Correction (NUC). It can be seen that PM-NN-NUC uses a similarity in the filtering process on Neural Network Non-Uniformity Correction and PM diffusion, and not only generates the expectation directly but also calculates the iterative step. Correction coefficient reacts on PM diffusion process and combines with PM diffusion and Neural Network Non-Uniformity Correction uniformly. The results of real infrared thermal image show that the proposed algorithm eliminates the fixed pattern noise effectively, but also has excellent performance for the image degraded with fade-out.

  13. Design of equivalent pixel circuit for infrared focal plane array%用于红外焦平面阵列的等效像元电路设计

    Institute of Scientific and Technical Information of China (English)

    戴山彪; 陈力颖; 邢海英; 王健; 杨晓龙

    2015-01-01

    An equivalent pixel circuit for 300 ×400 infrared focal plane array readout circuit structure is presented in this paper.The circuit′s electrical characteristics are equivalent to that of the vanadium oxide (VOx film)micro -mechanical systems (MEMS).It can simulate the variation of the branch current when the MEMS pixel changes.Be-fore the growth of physical structure of MEMS (VOx film),the infrared array detector readout circuit has been fabrica-ted.The equivalent pixel circuit is designed to test the electrical properties of the readout circuit.It can remove the defective products and reduce packaging costs.The circuit has been designed and fabricated with a GlobalFoundry 0.35 μm process.The test results indicate that the equivalent circuit has the same electrical properties as the MEMS pixel when the integrating current is 0 ~200 nA.%提出了一种用于300×400红外焦平面阵列读出电路的等效像元电路结构。该电路与氧化钒(VOx 薄膜)制成的微机械系统(MEMS)的电特性等效,并能够模拟 MEMS 像元改变时支路电流的变化。红外面阵探测器读出电路在流片后,生长 MEMS 物理结构(VOx 薄膜)前,该等效像元电路结构用于读出电路的电性能测试,从而剔除不良品,减少封装成本。该电路采用了 GlobalFoundry 0.35μm 工艺设计并流片。测试结果表明,当积分电流为0~200 nA 时,该等效像元电路的电性能与 MEMS 像元一致。

  14. Large-Area, UV-Optimized, Back-Illuminated Silicon Photomultiplier Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Large-area (3m2), UV-sensitive focal plane arrays are needed for observation of air showers from ultra-high energy cosmic rays (JEM-EUSO) as well as for...

  15. Atypical language laterality is associated with large-scale disruption of network integration in children with intractable focal epilepsy.

    Science.gov (United States)

    Ibrahim, George M; Morgan, Benjamin R; Doesburg, Sam M; Taylor, Margot J; Pang, Elizabeth W; Donner, Elizabeth; Go, Cristina Y; Rutka, James T; Snead, O Carter

    2015-04-01

    Epilepsy is associated with disruption of integration in distributed networks, together with altered localization for functions such as expressive language. The relation between atypical network connectivity and altered localization is unknown. In the current study we tested whether atypical expressive language laterality was associated with the alteration of large-scale network integration in children with medically-intractable localization-related epilepsy (LRE). Twenty-three right-handed children (age range 8-17) with medically-intractable LRE performed a verb generation task in fMRI. Language network activation was identified and the Laterality index (LI) was calculated within the pars triangularis and pars opercularis. Resting-state data from the same cohort were subjected to independent component analysis. Dual regression was used to identify associations between resting-state integration and LI values. Higher positive values of the LI, indicating typical language localization were associated with stronger functional integration of various networks including the default mode network (DMN). The normally symmetric resting-state networks showed a pattern of lateralized connectivity mirroring that of language function. The association between atypical language localization and network integration implies a widespread disruption of neural network development. These findings may inform the interpretation of localization studies by providing novel insights into reorganization of neural networks in epilepsy.

  16. Vortex pinning and lock-in effect in a layered superconductor with large in-plane anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Mansky, P.A.; Danner, G.; Chaikin, P.M. [Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)

    1995-09-01

    We use ac susceptibility to study the vortex pinning force anisotropy and the magnetic lock-in effect in the organic superconductor (TMTSF){sub 2}ClO{sub 4}, which is believed to have an in-plane anisotropy of {gamma}{sub {ital b}{ital a}}{similar_to}10 and a maximum out-of-plane anisotropy {gamma}{sub {ital c}{ital a}}{similar_to}100. Our measurements show only weak effects of the in-plane anisotropy. The pinning force for Josephson vortices (parallel to the conducting planes) is nearly independent of their orientation, except for a small but narrow peak (full width at half maximum {congruent}6{degree}) when the vortices are parallel to the TMTSF stacks ({ital a} axis). The pinning force initially {ital decreases} {ital as} {ital the} {ital vortices} {ital unlock} {ital from} {ital the} {ital layers}, contrary to the behavior previously observed in the organic superconductor (BEDT-TTF){sub 2}Cu(SCN){sub 2}. The lock-in threshold field is only weakly dependent on the initial angle of the Josephson vortices in the {ital ab} plane.

  17. A novel orally available inhibitor of focal adhesion signaling increases survival in a xenograft model of diffuse large B-cell lymphoma with central nervous system involvement.

    Science.gov (United States)

    Bosch, Rosa; Moreno, María José; Dieguez-Gonzalez, Rebeca; Céspedes, María Virtudes; Gallardo, Alberto; Trias, Manuel; Grañena, Albert; Sierra, Jorge; Casanova, Isolda; Mangues, Ramon

    2013-08-01

    Central nervous system dissemination is a relatively uncommon but almost always fatal complication in diffuse large B-cell lymphoma patients. Optimal therapy for central nervous involvement in this malignancy has not been established. In this paper, we aimed to evaluate the therapeutic effect of E7123, a celecoxib derivative that inhibits focal adhesion signaling, in a novel xenograft model of diffuse large B-cell lymphoma with central nervous system involvement. Cells obtained after disaggregation of HT subcutaneous tumors (HT-SC cells) were intravenously injected in NOD/SCID mice. These mice received oral vehicle or 75 mg/kg of E7123 daily until they were euthanized for weight loss or signs of sickness. The antitumor effect of E7123 was validated in an independent experiment using a bioluminescent mouse model. Intravenously injected HT-SC cells showed higher take rate and higher central nervous system tropism (associated with increased expression of β1-integrin and p130Cas proteins) than HT cells. The oral administration of E7123 significantly increased survival time in 2 independent experiments using mice injected with unmodified or bioluminescent HT-SC cells. We have developed a new xenograft model of diffuse large B-cell lymphoma with central nervous system involvement that can be used in the pre-clinical evaluation of new drugs for this malignancy. E7123 is a new, well-tolerated and orally available therapeutic agent that merits further investigation since it may improve current management of diffuse large B-cell lymphoma patients with central nervous system involvement.

  18. Large field SPIV with separated sheets in a spanwise plane of a turbulent boundary layer with vortex generators

    DEFF Research Database (Denmark)

    Foucaut, J.M.; Coudert, S.; Braud, C.

    2012-01-01

    The Stereoscopic PIV is nowadays a well established measurement technique for turbulent flows. However, the accuracy and the spatial resolution are still highly questionable in presence of complex flow with both strong gradients and out of plane motions. To give guidelines for both setup and meas......The Stereoscopic PIV is nowadays a well established measurement technique for turbulent flows. However, the accuracy and the spatial resolution are still highly questionable in presence of complex flow with both strong gradients and out of plane motions. To give guidelines for both setup...

  19. Scalable fine-grained parallelization of plane-wave-based ab initio molecular dynamics for large supercomputers.

    Science.gov (United States)

    Vadali, Ramkumar V; Shi, Yan; Kumar, Sameer; Kale, Laxmikant V; Tuckerman, Mark E; Martyna, Glenn J

    2004-12-01

    Many systems of great importance in material science, chemistry, solid-state physics, and biophysics require forces generated from an electronic structure calculation, as opposed to an empirically derived force law to describe their properties adequately. The use of such forces as input to Newton's equations of motion forms the basis of the ab initio molecular dynamics method, which is able to treat the dynamics of chemical bond-breaking and -forming events. However, a very large number of electronic structure calculations must be performed to compute an ab initio molecular dynamics trajectory, making the efficiency as well as the accuracy of the electronic structure representation critical issues. One efficient and accurate electronic structure method is the generalized gradient approximation to the Kohn-Sham density functional theory implemented using a plane-wave basis set and atomic pseudopotentials. The marriage of the gradient-corrected density functional approach with molecular dynamics, as pioneered by Car and Parrinello (R. Car and M. Parrinello, Phys Rev Lett 1985, 55, 2471), has been demonstrated to be capable of elucidating the atomic scale structure and dynamics underlying many complex systems at finite temperature. However, despite the relative efficiency of this approach, it has not been possible to obtain parallel scaling of the technique beyond several hundred processors on moderately sized systems using standard approaches. Consequently, the time scales that can be accessed and the degree of phase space sampling are severely limited. To take advantage of next generation computer platforms with thousands of processors such as IBM's BlueGene, a novel scalable parallelization strategy for Car-Parrinello molecular dynamics is developed using the concept of processor virtualization as embodied by the Charm++ parallel programming system. Charm++ allows the diverse elements of a Car-Parrinello molecular dynamics calculation to be interleaved with low

  20. Fabrication of flexible oriented magnetic thin films with large in-plane uniaxial anisotropy by roll-to-roll nanoimprint lithography

    Science.gov (United States)

    Thantirige, Rukshan M.; John, Jacob; Pradhan, Nihar R.; Carter, Kenneth R.; Tuominen, Mark T.

    2016-06-01

    Here, we report wafer scale fabrication of densely packed Fe nanostripe-based magnetic thin films on a flexible substrate and their magnetic anisotropy properties. We find that Fe nanostripes exhibit large in-plane uniaxial anisotropy and nearly square hysteresis loops with energy products (BHmax) exceeding 3 MGOe at room temperature. High density Fe nanostripes were fabricated on 70 nm flexible polyethylene terephthalate (PET) gratings, which were made by a roll-to-roll (R2R) UV nanoimprint lithography technique. We observed large in-plane uniaxial anisotropies along the long dimension of nanostripes that can be attributed to the shape. Temperature dependent hysteresis measurements confirm that the magnetization reversal is driven by non-coherent rotation reversal processes.

  1. Stress tensor and focal mechanisms in the Dead Sea basin

    Science.gov (United States)

    Hofstetter, A.; Dorbath, C.; Dorbath, L.; Braeuer, B.; Weber, M.

    2016-04-01

    We use the recorded seismicity, confined to the Dead Sea basin and its boundaries, by the Dead Sea Integrated Research (DESIRE) portable seismic network and the Israel and Jordan permanent seismic networks for studying the mechanisms of earthquakes in the Dead Sea basin. The observed seismicity in the Dead Sea basin is divided into nine regions according to the spatial distribution of the earthquakes and the known tectonic features. The large number of recording stations and the adequate station distribution allowed the reliable determinations of 494 earthquake focal mechanisms. For each region, based on the inversion of the observed polarities of the earthquakes, we determine the focal mechanisms and the associated stress tensor. For 159 earthquakes, out of the 494 focal mechanisms, we could determine compatible fault planes. On the eastern side, the focal mechanisms are mainly strike-slip mechanism with nodal planes in the N-S and E-W directions. The azimuths of the stress axes are well constrained presenting minimal variability in the inversion of the data, which is in agreement with the Eastern Boundary fault on the east side of the Dead Sea basin and what we had expected from the regional geodynamics. However, larger variabilities of the azimuthal and dip angles are observed on the western side of the basin. Due to the wider range of azimuths of the fault planes, we observe the switching of σ1 and σ2 or the switching of σ2 and σ3 as major horizontal stress directions. This observed switching of stress axes allows having dip-slip and normal mechanisms in a region that is dominated by strike-slip motion.

  2. Vergence and accommodation to multiple-image-plane stereoscopic displays: 'Real world' responses with practical image-plane separations?

    Science.gov (United States)

    MacKenzie, K. J.; Dickson, R. A.; Watt, S. J.

    2011-03-01

    Conventional stereoscopic displays present images on a single focal plane. The resulting mismatch between the stimuli to the eyes' focusing response (accommodation) and to convergence causes fatigue and poor stereo performance. One promising solution is to distribute image intensity across a number of relatively widely spaced image planes - a technique referred to as depth filtering. Previously, we found this elicits accurate, continuous monocular accommodation responses with image-plane separations as large as 1.1 Diopters, suggesting that a relatively small (i.e. practical) number of image planes is sufficient to eliminate vergence-accommodation conflicts over a large range of simulated distances. However, accommodation responses have been found to overshoot systematically when the same stimuli are viewed binocularly. Here, we examined the minimum image-plane spacing required for accurate accommodation to binocular depth-filtered images. We compared accommodation and vergence responses to step changes in depth for depth-filtered stimuli, using image-plane separations of 0.6-1.2 D, and equivalent real stimuli. Accommodation responses to real and depth-filtered stimuli were equivalent for image-plane separations of ~0.6-0.9 D, but inaccurate thereafter. We conclude that depth filtering can be used to precisely match accommodation and vergence demand in a practical stereoscopic display, using a relatively small number of image planes.

  3. Fabrication of Flexible Oriented Magnetic Thin Films with Large in-plane Uniaxial Anisotropy by Roll-to-roll Nanoimprint Lithography

    OpenAIRE

    Thantirige, Rukshan M.; John, Jacob; Pradhan, Nihar R.; Carter, Kenneth R.; Tuominen, Mark T.

    2015-01-01

    Here, we report wafer scale fabrication of densely packed Fe nanostripe-based magnetic thin films on a flexible substrate and their magnetic anisotropy properties. We find that Fe nanostripes exhibit large in-plane uniaxial anisotropy and nearly square hysteresis loops with energy products (BH)max exceeding 3 MGOe at room temperature. High density Fe nanostripes were fabricated on 70 nm flexible polyethylene terephthalate (PET) gratings, which were made by roll-to-roll (R2R) UV nanoimprintlit...

  4. Vergence and accommodation to multiple-image-plane stereoscopic displays: ``real world'' responses with practical image-plane separations?

    Science.gov (United States)

    MacKenzie, Kevin J.; Dickson, Ruth A.; Watt, Simon J.

    2012-01-01

    Conventional stereoscopic displays present images on a single focal plane. The resulting mismatch between the stimuli to the eyes' focusing response (accommodation) and to convergence causes fatigue and poor stereo performance. One solution is to distribute image intensity across a number of widely spaced image planes--a technique referred to as depth filtering. Previously, we found this elicits accurate, continuous monocular accommodation responses with image-plane separations as large as 1.1 Diopters (D, the reciprocal of distance in meters), suggesting that a small number of image planes could eliminate vergence-accommodation conflicts over a large range of simulated distances. Evidence exists, however, of systematic differences between accommodation responses to binocular and monocular stimuli when the stimulus to accommodation is degraded, or at an incorrect distance. We examined the minimum image-plane spacing required for accurate accommodation to binocular depth-filtered images. We compared accommodation and vergence responses to changes in depth specified by depth filtering, using image-plane separations of 0.6 to 1.2 D, and equivalent real stimuli. Accommodation responses to real and depth-filtered stimuli were equivalent for image-plane separations of ~0.6 to 0.9 D, but differed thereafter. We conclude that depth filtering can be used to precisely match accommodation and vergence demand in a practical stereoscopic display.

  5. Three-Dimensional Interaction of a Large Number of Dense DEP Particles on a Plane Perpendicular to an AC Electrical Field

    Directory of Open Access Journals (Sweden)

    Chuanchuan Xie

    2017-01-01

    Full Text Available The interaction of dielectrophoresis (DEP particles in an electric field has been observed in many experiments, known as the “particle chains phenomenon”. However, the study in 3D models (spherical particles is rarely reported due to its complexity and significant computational cost. In this paper, we employed the iterative dipole moment (IDM method to study the 3D interaction of a large number of dense DEP particles randomly distributed on a plane perpendicular to a uniform alternating current (AC electric field in a bounded or unbounded space. The numerical results indicated that the particles cannot move out of the initial plane. The similar particles (either all positive or all negative DEP particles always repelled each other, and did not form a chain. The dissimilar particles (a mixture of positive and negative DEP particles always attracted each other, and formed particle chains consisting of alternately arranged positive and negative DEP particles. The particle chain patterns can be randomly multitudinous depending on the initial particle distribution, the electric properties of particles/fluid, the particle sizes and the number of particles. It is also found that the particle chain patterns can be effectively manipulated via tuning the frequency of the AC field and an almost uniform distribution of particles in a bounded plane chip can be achieved when all of the particles are similar, which may have potential applications in the particle manipulation of microfluidics.

  6. A Novel Technique for the Production of Large Area Z-coordinate Readout Planes for the BaBar Muon System

    Energy Technology Data Exchange (ETDEWEB)

    Convery, M.R.; Kim, P.C.; /SLAC; Paar, H.P.; /UC, San Diego; Rogers, C.H.; Schindler, R.H.; Swain, S.K.; Young, C.C.; /SLAC

    2005-09-30

    The BABAR detector, at the Stanford Linear Accelerator Center is a general purpose detector for the study of e{sup +}e{sup -} interactions at the {Upsilon}(4S) resonance. BABAR's muon detection system consists of two parts: a hexagonal barrel region and two planar endcap regions each containing 18 layers of iron ({approx} 3.6{lambda}), with resistive plate chambers within the inter-iron gaps. These chambers have suffered deterioration in performance over the past few years and are being replaced by limited streamer tube chambers in the barrel. Each layer of the system consists of a set of up to 10 streamer tube modules oriented parallel to the beamline providing the azimuthal coordinate ({Phi}) and a single ''Z-plane'' with strips oriented perpendicular the streamer tubes providing the coordinate (Z) along the beamline. The large area Z-planes (up to 12 m{sup 2}) are 1 mm thick and contain 96 strips that detect the induced charge from avalanches on the streamer tube wires. This paper reports on the novel construction technique of the Z-planes.

  7. Dispersive growth and laser-induced rippling of large-area singlelayer MoS2 nanosheets by CVD on c-plane sapphire substrate

    Science.gov (United States)

    Liu, Hongfei; Chi, Dongzhi

    2015-06-01

    Vapor-phase growth of large-area two-dimensional (2D) MoS2 nanosheets via reactions of sulfur with MoO3 precursors vaporized and transferred from powder sources onto a target substrate has been rapidly progressing. Recent studies revealed that the growth yield of high quality singlelayer (SL) MoS2 is essentially controlled by quite a few parameters including the temperature, the pressure, the amount/weight of loaded source precursors, and the cleanup of old precursors. Here, we report a dispersive growth method where a shadow mask is encapsulated on the substrate to ‘indirectly’ supply the source precursors onto the laterally advancing growth front at elevated temperatures. With this method, we have grown large-area (up to millimeters) SL-MoS2 nanosheets with a collective in-plane orientation on c-plane sapphire substrates. Regular ripples (~1 nm in height and ~50 nm in period) have been induced by laser scanning into the SL-MoS2 nanosheets. The MoS2 ripples easily initiate at the grain boundaries and extend along the atomic steps of the substrate. Such laser-induced ripple structures can be fundamental materials for studying their effects, which have been predicted to be significant but hitherto not evidenced, on the electronic, mechanical, and transport properties of SL-MoS2.

  8. Thin power law film flow down an inclined plane: consistent shallow water models and stability under large scale perturbations

    CERN Document Server

    Noble, Pascal

    2012-01-01

    In this paper we derive consistent shallow water equations for thin films of power law fluids down an incline. These models account for the streamwise diffusion of momentum which is important to describe accurately the full dynamic of the thin film flows when instabilities like roll-waves arise. These models are validated through a comparison with Orr Sommerfeld equations for large scale perturbations. We only consider laminar flow for which the boundary layer issued from the interaction of the flow with the bottom surface has an influence all over the transverse direction to the flow. In this case the concept itself of thin film and its relation with long wave asymptotic leads naturally to flow conditions around a uniform free surface Poiseuille flow. The apparent viscosity diverges at the free surface which, in turn, introduces a singularity in the formulation of the Orr-Sommerfeld equations and in the derivation of shallow water models. We remove this singularity by introducing a weaker formulation of Cauc...

  9. [Asterixis in focal brain lesions].

    Science.gov (United States)

    Velasco, F; Gomez, J C; Zarranz, J J; Lambarri, I; Ugalde, J

    2004-05-01

    Asterixis is a motor control disorder characterized by the presence of abnormal movements of the lower limbs in the vertical plane during posture maintenance. Asterixis is usually bilateral and associated with toxic-metabolic metabolic encephalopathies. Unilateral asterixis is less frequent and it normally indicates focal brain damage. We report the cases of four patients (two males/two females), aged 57 to 83 years, suffering from uni or bilateral asterixis associated with focal brain damage. All patients underwent CT brain scan and a neurophysiological study (parietal EMG and/or PES). In addition, any toxic-metabolic cause that could be produced by this clinical phenomenon was ruled out with the appropriate testing. Unilateral asterixis is a clinical symptom that may indicate the presence of focal brain damage. Often, it is ignored or overlooked during routine neurological examinations. On the other hand, the presence of a bilateral asterixis is not always indicative of a toxic-metabolic encephalopathy.Rarely, such as in one of the cases herein presented, bilateral asterixis can also appear associated with structural brain lesions. Although asterixis diagnosis is fundamentally clinical, the neurophysiological study contributes to verify the diagnosis.

  10. A Census of Large-Scale ($\\ge$ 10 pc), Velocity-Coherent, Dense Filaments in the Northern Galactic Plane: Automated Identification Using Minimum Spanning Tree

    CERN Document Server

    Wang, Ke; Burkert, Andreas; Walmsley, C Malcolm; Beuther, Henrik; Henning, Thomas

    2016-01-01

    Large-scale gaseous filaments with length up to the order of 100 pc are on the upper end of the filamentary hierarchy of the Galactic interstellar medium. Their association with respect to the Galactic structure and their role in Galactic star formation are of great interest from both observational and theoretical point of view. Previous "by-eye" searches, combined together, have started to uncover the Galactic distribution of large filaments, yet inherent bias and small sample size limit conclusive statistical results to be drawn. Here, we present (1) a new, automated method to identify large-scale velocity-coherent dense filaments, and (2) the first statistics and the Galactic distribution of these filaments. We use a customized minimum spanning tree algorithm to identify filaments by connecting voxels in the position-position-velocity space, using the Bolocam Galactic Plane Survey spectroscopic catalog. In the range of $7.^{\\circ}5 \\le l \\le 194^{\\circ}$, we have identified 54 large-scale filaments and der...

  11. Comparison of different approaches to the numerical calculation of the LMJ focal

    Directory of Open Access Journals (Sweden)

    Bourgeade A.

    2013-11-01

    Full Text Available The beam smoothing in the focal plane of high power lasers is of particular importance to laser-plasma interaction studies in order to minimize plasma parametric and hydrodynamic instabilities on the target. Here we investigate the focal spot structure in different geometrical configurations where standard paraxial hypotheses are no longer verified. We present numerical studies in the cases of single flat top square beam, LMJ quadruplet and complete ring of quads with large azimuth angle. Different calculations are made with Fresnel diffraction propagation model in the paraxial approximation and full vector Maxwell's equations. The first model is based on Fourier transform from near to far field method. The second model uses first spherical wave decomposition in plane waves with Fourier transform and propagates them to the focal spot. These two different approaches are compared with Miró [1] modeling results using paraxial or Feit and Fleck options. The methods presented here are generic for focal spot calculations. They can be used for other complex geometric configurations and various smoothing techniques. The results will be used as boundary conditions in plasma interaction computations.

  12. FORMATION OF THE INITIAL DISTRIBUTION OF PLASMA COMPONENTS ON THE PHASE PLANE OF LARGE PARTICLES METHOD IN ELECTRIC ARC SYNTHESIS CNS

    Directory of Open Access Journals (Sweden)

    G. V. Abramov

    2014-01-01

    Full Text Available The article deals with the modeling of charged particles in a multicomponent plasma of electric arc discharge with binary collisions in the synthesis of carbon nanostructures (CNS. One of the common methods of obtaining the quality of fullerenes and nanotubes is arc synthesis under inert gas (helium. The determination of the necessary conditions and the mechanism of formation of carbon clusters in the plasma forming set CNS will more effectively and efficiently manage this process. Feature of the problem is that in a plasma arc discharge is a large number of particle interactions and on the cathode surface. Due to the high temperatures and high energy concentration in plasma detailed experimental investigation difficult to carry out. With the aim of avoiding difficult and costly physical experiments developed numerical methods for the analysis of plasma processes. In this article to solve a system of equations of Maxwell - Boltzmann basis for the authors had taken the method of large particles, which reduces the amount of computation and reduce the demands on computing resources. The authors cites the general design scheme of the large particles, and the algorithm of particle distribution of a multicomponent plasma in the phase plane at the initial time. In conclusion, the author argues that the results in the future will define the zone satisfies the energy conditions, the probability of formation of a plasma cluster groups of carbon involved in the synthesis of the CNS.

  13. The precursory electric signals, observed before the Izmit Turkey EQ (Mw = 7.6, August 17th, 1999), analyzed in terms of a hypothetically pre-activated, in the focal area, large scale piezoelectric mechanism

    CERN Document Server

    Thanassoulas, C

    2011-01-01

    The generated, prior to the Izmit Turkey large EQ, preseismic electric signals were recorded in Greece by the VOL Earth's electric field monitoring site. In order to explain their peculiar character and their generating mechanism, a large scale piezoelectric mechanism was assumed that was initiated in the Izmit seismogenic region long before the EQ occurrence time. The theoretical analysis of the adopted physical model justifies the generation of a number of specific electric signals that can be emitted from the focal area before the rock formation failure. The processing of the registered by the VOL monitoring site raw data revealed the presence of similar signals as the expected theoretical ones. Therefore, it is concluded that long before the Izmit EQ occurrence a large scale piezoelectric mechanism was initiated that was modulated too by the tidally triggered lithospheric oscillation and therefore generated the observed preseismic electric signals. The adopted piezoelectric model provides critical informa...

  14. Research of aerial camera focal pane micro-displacement measurement system based on Michelson interferometer

    Science.gov (United States)

    Wang, Shu-juan; Zhao, Yu-liang; Li, Shu-jun

    2014-09-01

    The aerial camera focal plane in the correct position is critical to the imaging quality. In order to adjust the aerial camera focal plane displacement caused in the process of maintenance, a new micro-displacement measuring system of aerial camera focal plane in view of the Michelson interferometer has been designed in this paper, which is based on the phase modulation principle, and uses the interference effect to realize the focal plane of the micro-displacement measurement. The system takes He-Ne laser as the light source, uses the Michelson interference mechanism to produce interference fringes, changes with the motion of the aerial camera focal plane interference fringes periodically, and records the periodicity of the change of the interference fringes to obtain the aerial camera plane displacement; Taking linear CCD and its driving system as the interference fringes picking up tool, relying on the frequency conversion and differentiating system, the system determines the moving direction of the focal plane. After data collecting, filtering, amplifying, threshold comparing, counting, CCD video signals of the interference fringes are sent into the computer processed automatically, and output the focal plane micro displacement results. As a result, the focal plane micro displacement can be measured automatically by this system. This system uses linear CCD as the interference fringes picking up tool, greatly improving the counting accuracy and eliminated the artificial counting error almost, improving the measurement accuracy of the system. The results of the experiments demonstrate that: the aerial camera focal plane displacement measurement accuracy is 0.2nm. While tests in the laboratory and flight show that aerial camera focal plane positioning is accurate and can satisfy the requirement of the aerial camera imaging.

  15. Offshore double-planed shallow seismic zone in the NE Japan forearc region revealed by sP depth phases recorded by regional networks

    Science.gov (United States)

    Gamage, S.S.N.; Umino, N.; Hasegawa, A.; Kirby, S.H.

    2009-01-01

    We detected the sP depth phase at small epicentral distances of about 150 km or more in the seismograms of shallow earthquakes in the NE Japan forearc region. The focal depths of 1078 M > 3 earthquakes that occurred from 2000 to 2006 were precisely determined using the time delay of the sP phase from the initial P-wave arrival. The distribution of relocated hypocentres clearly shows the configuration of a double-planed shallow seismic zone beneath the Pacific Ocean. The upper plane has a low dip angle near the Japan Trench, increasing gradually to ???30?? at approximately 100 km landward of the Japan Trench. The lower plane is approximately parallel to the upper plane, and appears to be the near-trench counterpart of the lower plane of the double-planed deep seismic zone beneath the land area. The distance between the upper and lower planes is 28-32 km, which is approximately the same as or slightly smaller than that of the double-planed deep seismic zone beneath the land area. Focal mechanism solutions of the relocated earthquakes are determined from P-wave initial motion data. Although P-wave initial motion data for these offshore events are not ideally distributed on the focal sphere, we found that the upper-plane events that occur near the Japan Trench are characterized by normal faulting, whereas lower-plane events are characterized by thrust faulting. This focal mechanism distribution is the opposite to that of the double-planed deep seismic zone beneath the land area. The characteristics of these focal mechanisms for the shallow and deep doubled-planed seismic zones can be explained by a bending-unbending model of the subducting Pacific plate. Some of relocated earthquakes took place in the source area of the 1933 Mw8.4 Sanriku earthquake at depths of 10-23 km. The available focal mechanisms for these events are characterized by normal faulting. Given that the 1933 event was a large normal-fault event that occurred along a fault plane dipping landward, the

  16. 10.6μm激光对HgCdTe焦平面器件热应力的分析%Theoretical analysis of thermal-stress effect of HgCdTe infrared focal plane device induced by 10.6 μm laser

    Institute of Scientific and Technical Information of China (English)

    郝向南; 聂劲松; 李化; 卞进田; 雷鹏

    2012-01-01

    建立了HgCdTe红外焦平面器件的多膜层理论模型,利用有限元分析的方法,对10.6 μm激光辐照下HgCdTe红外焦平面器件的升温情况与热应力分布情况进行模拟,并通过参考已有文献的实验结果,验证了理论模型的合理性.理论分析结果表明:激光作用时探测器的温度场变化剧烈,200 W/cm2连续激光作用1 s后,HgCdTe感光层所受热应力为-986 MPa;脉宽100 ns,功率密度15 MW/cm2脉冲激光作用后,HgCdTe感光层所受热应力为-1300 MPa,都比器件制造过程中由于热失配而产生的热应力大;应力损伤发生的概率增大,可能比热损伤先发生,是HgCdTe红外焦平面器件激光损伤中的重要原因.%Muti-layer theoretical Model of HgCdTe Infrared Focal Plane Device was established. With the method of finite element analysis, temperature field and thermal-stress field induced by 10.6 μm laser were simulated. By considering experiments carried out in other papers as reference,the rationality and feasibility of the muti-layer model are proved. Results of theoretical analysis indicates that the temperature field changes greatly when irradiated by laser. With CW laser of 200 W/cm2 power density irradiating the sensor for 1 s, thermal-stress of HgCdTe photo-sensitive surface is -986MPa:With pulsed laser of 100 ns and 15 MW/cm2 irradiating the sensor,thermal-stress of HgCdTe photo-sensitive surface is - 1300 Mpa. The thermal-stress mentioned above are both beyond that caused by thermal-mismatch in the production process. Besides, the probability of thermal-stress damage increases and may happen before thermal damage,which should be an important factor in the research of laser damage to HgCdTe Infrared Focal Plane Device.

  17. Optimization Design of Long Focal Distance and Large Aperture Infrared Optical System%长焦距大口径红外光学系统的优化设计

    Institute of Scientific and Technical Information of China (English)

    付学志; 王日胜; 胡兵; 李岩

    2015-01-01

    针对某长焦距大口径光电设备的特殊要求,基于卡塞格林光学折反系统达到了较好的红外成像质量和紧凑的结构尺寸。首先通过计算对红外光学系统进行了初步焦距分配;然后对卡塞格林反射组件和红外组件进行了分段优化设计,特别是为克服温度变化对焦距和像质的影响,在后组设计三片透镜作为调焦组,保证了成像质量;最后,为了消除杂光的影响,分别对轴上、轴外光线进行追迹并设计了主、次镜遮光罩。设计结果分析表明主要指标均满足设计要求。%According to the special requirements of a large aperture and long focal length optical equipment, better quality of infrared imaging and compact structure was achieved based on Cassegrain optical catadioptric system. Firstly, focal length assignment was calculated. Then, Cassegrain reflect component and infrared component was optimized respectively. Specially, in order to overcome the impact of temperature’s change on focal length and image quality, designed three lenses as focus group. Lastly, the main and subordinate lens’s hoods were designed to eliminate the influence of stray light. The design results show that the main indexes meet the design requirements.

  18. La détection infrarouge avec les plans focaux non refroidis : état de l'artUncooled focal plane infrared detectors: the state of the art

    Science.gov (United States)

    Tissot, Jean-Luc

    2003-12-01

    The emergence of uncooled detectors has opened new opportunities for IR detection for both military and commercial applications. Development of such devices involves a lot of trade-offs between the different parameters that define the technological stack. These trade-offs explain the number of different architectures that are under worldwide development. The key factor is to find a high sensitivity and low noise thermometer material compatible with silicon technology in order to achieve high thermal isolation in the smallest area as possible. Ferroelectric thermometer based hybrid technology and electrical resistive thermometer based (microbolometer) technology are under development. LETI and ULIS have chosen from the very beginning to develop first a monolithic microbolometer technology fully compatible with commercially available CMOS technology and secondly amorphous silicon based thermometer. This silicon approach has the greatest potential for reducing infrared detector manufacturing cost. After the development of the technology, the transfer to industrial facilities has been performed in a short period of time and the production is now ramping up with ULIS team in new facilities. LETI and ULIS are now working to facilitate the IRFPA integration into equipment in order to address a very large market. Achievement of this goal needs the development of smart sensors with on-chip advanced functions and the decrease of manufacturing cost of IRFPA by decreasing the pixel pitch and simplifying the vacuum package. We present in this paper the technology developed by CEA/LETI and its improvement for being able to designs 384×288 and 160×120 arrays with a pitch of 35 μm. Thermographic application needs high stability infrared detector with a precise determination of the amount of absorbed infrared flux. Hence, infrared detector with internal temperature stabilized shield has been developed and characterized. These results will be presented. To cite this article: J

  19. Transparent meta-analysis: does aging spare prospective memory with focal vs. non-focal cues?

    Directory of Open Access Journals (Sweden)

    Bob Uttl

    Full Text Available BACKGROUND: Prospective memory (ProM is the ability to become aware of a previously-formed plan at the right time and place. For over twenty years, researchers have been debating whether prospective memory declines with aging or whether it is spared by aging and, most recently, whether aging spares prospective memory with focal vs. non-focal cues. Two recent meta-analyses examining these claims did not include all relevant studies and ignored prevalent ceiling effects, age confounds, and did not distinguish between prospective memory subdomains (e.g., ProM proper, vigilance, habitual ProM (see Uttl, 2008, PLoS ONE. The present meta-analysis focuses on the following questions: Does prospective memory decline with aging? Does prospective memory with focal vs. non-focal cues decline with aging? Does the size of age-related declines with focal vs. non-focal cues vary across ProM subdomains? And are age-related declines in ProM smaller than age-related declines in retrospective memory? METHODS AND FINDINGS: A meta-analysis of event-cued ProM using data visualization and modeling, robust count methods, and conventional meta-analysis techniques revealed that first, the size of age-related declines in ProM with both focal and non-focal cues are large. Second, age-related declines in ProM with focal cues are larger in ProM proper and smaller in vigilance. Third, age-related declines in ProM proper with focal cues are as large as age-related declines in recall measures of retrospective memory. CONCLUSIONS: The results are consistent with Craik's (1983 proposal that age-related declines on ProM tasks are generally large, support the distinction between ProM proper vs. vigilance, and directly contradict widespread claims that ProM, with or without focal cues, is spared by aging.

  20. Bimaxillary Oral Focal Mucinosis.

    Science.gov (United States)

    Yadav, Sunil; Malik, Sunita; Mittal, Hitesh Chander; Singh, Gurdarshan; Kamra, Hemlata

    2016-10-01

    Oral focal mucinosis is considered as oral counterpart of cutaneous focal mucinosis. The preoperative diagnosis of mucinosis is almost impossible because of its rarity and clinical similarity to other lesions of various etiologies. The histological diagnosis of oral mucinosis is important to better understand the etiopathogenesis, treatment modalities, and any recurrence of the lesion besides differentiating from the other soft tissue lesions.The purpose of this paper is to report the first case of bimaxillary involvement with dome-shaped elevated, rounded, asymptomatic, normally colored swelling in left posterior palatal mucosa and left mandibular posterior region in a 25-year old woman who was diagnosed as oral focal mucinosis histopathologically.

  1. Focal neurological deficits

    Science.gov (United States)

    ... Other examples of focal loss of function include: Horner syndrome : small pupil on one side, one-sided ... 403. Read More Alertness - decreased Fine motor control Horner syndrome Hypotonia Movement - uncoordinated Muscle function loss Neurologic ...

  2. Large Sky Area Multi-Object Fiber Spectroscopic Telescope

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yongheng

    2011-01-01

    The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is a meridian reflecting Schmidt telescope with a clear aperture of four meters, a focal length of 20 meters and a field of view of five degrees. By using active optics technique to control its reflecting corrector, the LAMOST is made a unique astronomical instrument in combining a large aperture with a wide field of view. The available large focal plane of 1.75 meter in diameter can accommodate up to 4,000 fibers,

  3. Monolithic Micromachined Quartz Resonator based Infrared Focal Plane Arrays

    Science.gov (United States)

    2012-05-05

    etching of glass using nitrogen trifluoride based gas . MEMS Personnel Working on the Project • Dr. Srinivas Tadigadapa, Professor, Penn State...source could be varied. • The RF power supplied operated at 13.56 MHz. RF Power Supply RF Matching Network Gas Inlet ICP Source Antenna Magnetic...500-2000 Substrate Power Watts 100-475 O2 Flow Rate sccm 5-100 SF6 Flow Rate sccm 5-50 C4F8 Flow Rate sccm 5-50 CH4 Flow Rate sccm 5-50 Ar Flow

  4. Flexible focal plane arrays for UVOIR wide field instrumentation

    CERN Document Server

    Hugot, Emmanuel; Chambion, Bertrand; Moulin, Gaid; Nikitushkina, Liubov; Gaschet, Christophe; Henry, David; Getin, Stéphane; Ferrari, Marc; Gaeremynck, Yann

    2016-01-01

    LAM and CEA-LETI are developing the technology of deformable detectors, for UV, VIS or NIR applications. Such breakthrough devices will be a revolution for future wide field imagers and spectrographs, firstly by improving the image quality with better off-axis sharpness, resolution, brightness while scaling down the optical system, secondly by overcoming the manufacturing issues identified so far and by offering a flexibility and versatility in optical design. The technology of curved detectors can benefit of the developments of active and deformable structures, to provide a flexibility and a fine tuning of the detectors curvature by thinning down the substrate without modifying the fabrication process of the active pixels. We present studies done so far on optical design improvements, the technological demonstrators we developed and their performances as well as the future five-years roadmap for these developments.

  5. Polarimetric Multiwavelength Focal Plane Arrays for ACE and CLARREO Project

    Data.gov (United States)

    National Aeronautics and Space Administration — High-performance polarimetric and nonpolarimetric sensing is crucial to upcoming NASA missions, including ACE and CLARREO and the multi-agency VIIRS NPP project. The...

  6. Low-noise readout circuit for SWIR focal plane arrays

    Science.gov (United States)

    Altun, Oguz; Tasdemir, Ferhat; Nuzumlali, Omer Lutfi; Kepenek, Reha; Inceturkmen, Ercihan; Akyurek, Fatih; Tunca, Can; Akbulut, Mehmet

    2017-02-01

    This paper reports a 640x512 SWIR ROIC with 15um pixel pitch that is designed and fabricated using 0.18um CMOS process. Main challenge of SWIR ROIC design is related to input circuit due to pixel area and noise limitations. In this design, CTIA with single stage amplifier is utilized as input stage. The pixel design has three pixel gain options; High Gain (HG), Medium Gain (MG), and Low Gain (LG) with corresponding Full-Well-Capacities of 18.7ké, 190ké and 1.56Mé, respectively. According to extracted simulation results, 5.9é noise is achieved at HG mode and 200é is achieved at LG mode of operation. The ROIC can be programmed through an SPI interface. It supports 1, 2 and 4 output modes which enables the user to configure the detector to work at 30, 60 and 120fps frame rates. In the 4 output mode, the total power consumption of the ROIC is less than 120mW. The ROIC is powered from a 3.3V analog supply and allows for an output swing range in excess of 2V. Anti-blooming feature is added to prevent any unwanted blooming effect during readout.

  7. Thermal Microphotonic Focal Plane Array (TM-FPA).

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, Frederick Bossert; Lentine, Anthony L.; Wright, Jeremy Benjamin; Watts, Michael R.; Shaw, Michael J.; Rakich, Peter T.; Nielson, Gregory N.; Peters, David William; Zortman, William A.

    2009-10-01

    The advent of high quality factor (Q) microphotonic-resonators has led to the demonstration of high-fidelity optical sensors of many physical phenomena (e.g. mechanical, chemical, and biological sensing) often with far better sensitivity than traditional techniques. Microphotonic-resonators also offer potential advantages as uncooled thermal detectors including significantly better noise performance, smaller pixel size, and faster response times than current thermal detectors. In particular, microphotonic thermal detectors do not suffer from Johnson noise in the sensor, offer far greater responsivity, and greater thermal isolation as they do not require metallic leads to the sensing element. Such advantages make the prospect of a microphotonic thermal imager highly attractive. Here, we introduce the microphotonic thermal detection technique, present the theoretical basis for the approach, discuss our progress on the development of this technology and consider future directions for thermal microphotonic imaging. Already we have demonstrated viability of device fabrication with the successful demonstration of a 20{micro}m pixel, and a scalable readout technique. Further, to date, we have achieved internal noise performance (NEP{sub Internal} < 1pW/{radical}Hz) in a 20{micro}m pixel thereby exceeding the noise performance of the best microbolometers while simultaneously demonstrating a thermal time constant ({tau} = 2ms) that is five times faster. In all, this results in an internal detectivity of D*{sub internal} = 2 x 10{sup 9}cm {center_dot} {radical}Hz/W, while roughly a factor of four better than the best uncooled commercial microbolometers, future demonstrations should enable another order of magnitude in sensitivity. While much work remains to achieve the level of maturity required for a deployable technology, already, microphotonic thermal detection has demonstrated considerable potential.

  8. InGaAs focal plane array developments and perspectives

    Science.gov (United States)

    Rouvié, A.; Coussement, J.; Huet, O.; Truffer, J. P.; Pozzi, M.; Oubensaid, E. H.; Hamard, S.; Chaffraix, V.; Costard, E.

    2015-05-01

    SWIR spectral band is an attractive domain thanks to its intrinsic properties. Close to visible wavelengths, SWIR images interpretation is made easier for field actors. Besides complementary information can be extracted from SWIR band and bring significant added value in several fields of applications such as defense and security (night vision, active imaging), space (earth observation), transport (automotive safety) or industry (non destructive process control). Among the various new technologies able to detect SWIR wavelengths, InGaAs appears as a key technology. Initially developed for optical telecommunications, this material guaranties performances, stability and reliability and is compatible with attractive production capacity. Thanks to high quality material, very low dark current levels can be achieved at ambient temperature. Then uncooled operation can be set up, allowing compact and low power systems. Since the recent transfer of InGaAs imaging activities from III-Vlab, Sofradir provides a framework for the production activity with the manufacturing of high performances products: CACTUS320 SW. The developments towards VGA format with 15μm pixel pitch, lead today to the industrialization of a new product: SNAKE. On one side, the InGaAs detection array presents high performances in terms of dark current and quantum efficiency. On the other side, the low noise ROIC has different additional functionalities. Then this 640x512 @ 15μm sensor appears as well suited to answer the needs of a wide range of applications. In this paper, we will present the Sofradir InGaAs technology, the performances of our last product SNAKE and the perspectives of InGaAs new developments.

  9. Design and alignment of the MIPAS focal plane system

    NARCIS (Netherlands)

    Smorenburg, C.; Visser, H.; Moddemeijer, K.

    1996-01-01

    The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is selected by ESA for the ENVISAT-mission, scheduled for launch in 1999. The instrument will measure the concentration of atmospheric trace gases in the earth atmosphere in a spectral region from 4.15-14.6 rim. MIPAS consists of

  10. Infrared Focal Plane Arrays Based on Semiconductor Quantum Dots

    Science.gov (United States)

    2002-01-01

    studied in the framework of this, including the collaborating researchers in each of them, are detailed below: 1. “Ultra Small InAs/GaInP/ InP Quantum Dots ”: with...of detectors, which will be attached to Si based signal processors. D:\\FINAL REPORT.doc 4 Part 1 Ultra Small InAs/GaInP/ InP Quantum Dots The heights of...an ensemble of self-assembled InAs/GaAs or InAs/ InP quantum dots (QDs) are typically in the range of 10-30 monolayers [1]. Here, we report on InAs

  11. Planck focal plane instruments: advanced modelization and combined analysis

    Science.gov (United States)

    Zonca, Andrea; Mennella, Aniello

    2012-08-01

    This thesis is the result of my work as research fellow at IASF-MI, Milan section of the Istituto di Astrofisica Spaziale e Fisica Cosmica, part of INAF, Istituto Nazionale di Astrofisica. This work started in January 2006 in the context of the PhD school program in Astrophysics held at the Physics Department of Universita' degli Studi di Milano under the supervision of Aniello Mennella. The main topic of my work is the software modelling of the Low Frequency Instrument (LFI) radiometers. The LFI is one of the two instruments on-board the European Space Agency Planck Mission for high precision measurements of the anisotropies of the Cosmic Microwave Background (CMB). I was also selected to participate at the International Doctorate in Antiparticles Physics, IDAPP. IDAPP is funded by the Italian Ministry of University and Research (MIUR) and coordinated by Giovanni Fiorentini (Universita' di Ferrara) with the objective of supporting the growing collaboration between the Astrophysics and Particles Physics communities. It is an international program in collaboration with the Paris PhD school, involving Paris VI, VII and XI Universities, leading to a double French-Italian doctoral degree title. My work was performed with the co-tutoring of Jean-Michel Lamarre, Instrument Scientist of the High Frequency Instrument (HFI), the bolometric instrument on-board Planck. Thanks to this collaboration I had the opportunity to work with the HFI team for four months at the Paris Observatory, so that the focus of my activity was broadened and included the study of cross-correlation between HFI and LFI data. Planck is the first CMB mission to have on-board the same satellite very different detection technologies, which is a key element for controlling systematic effects and improve measurements quality.

  12. MEMS Terahertz Focal Plane Array With Optical Readout

    Science.gov (United States)

    2016-06-01

    V. CONCLUSION ......................................................................................... 49 APPENDIX A. MATLAB CODE FOR THZ TO IR...EXPERIMENTAL RESULTS ................................................................................................ 51 APPENDIX B. MATLAB CODE FOR...THZ TO IR SIMULATION RESULTS ...... 55 APPENDIX C. MATLAB CODE FOR LENS SETUP .......................................... 61 APPENDIX D. ACHROMAT

  13. Plasmonic Enhanced Type-II Superlattice Focal Plane Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SVT Associates proposes an novel type II superlattice structure to extend the cutoff wavelength and CBIRD SL photo diode structure with unipolar barriers to suppress...

  14. NIRCA ASIC for the readout of focal plane arrays

    Science.gov (United States)

    Pâhlsson, Philip; Steenari, David; Øya, Petter; Otnes Berge, Hans Kristian; Meier, Dirk; Olsen, Alf; Hasanbegovic, Amir; Altan, Mehmet A.; Najafiuchevler, Bahram; Talebi, Jahanzad; Azman, Suleyman; Gheorghe, Codin; Ackermann, Jörg; Mæhlum, Gunnar; Johansen, Tor Magnus; Stein, Timo

    2016-05-01

    This work is a continuation of our preliminary tests on NIRCA - the Near Infrared Readout and Controller ASIC [1]. The primary application for NIRCA is future astronomical science and Earth observation missions where NIRCA will be used with mercury cadmium telluride image sensors (HgCdTe, or MCT) [2], [3]. Recently we have completed the ASIC tests in the cryogenic environment down to 77 K. We have verified that NIRCA provides to the readout integrated circuit (ROIC) regulated power, bias voltages, and fully programmable digital sequences with sample control of the analogue to digital converters (ADC). Both analog and digital output from the ROIC can be acquired and image data is 8b/10bencoded and delivered via serial interface. The NIRCA also provides temperature measurement, and monitors several analog and digital input channels. The preliminary work confirms that NIRCA is latch-up immune and able to operate down to 77 K. We have tested the performance of the 12-bit ADC with pre-amplifier to have 10.8 equivalent number of bits (ENOB) at 1.4 Msps and maximum sampling speed at 2 Msps. The 1.8-V and 3.3-V output regulators and the 10-bit DACs show good linearity and work as expected. A programmable sequencer is implemented as a micro-controller with a custom instruction set. Here we describe the special operations of the sequencer with regards to the applications and a novel approach to parallel real-time hardware outputs. The test results of the working prototype ASIC show good functionality and performance from room temperature down to 77 K. The versatility of the chip makes the architecture a possible candidate for other research areas, defense or industrial applications that require analog and digital acquisition, voltage regulation, and digital signal generation.

  15. Phase stability and large in-plane resistivity anisotropy in the 112-type iron-based superconductor Ca1 -xLaxFeAs2

    Science.gov (United States)

    Kang, Chang-Jong; Birol, Turan; Kotliar, Gabriel

    2017-01-01

    The recently discovered high-Tc superconductor Ca1 -xLaxFeAs2 is a unique compound not only because of its low-symmetry crystal structure but also because of its electronic structure, which hosts Dirac-like metallic bands resulting from (spacer) zigzag As chains. We present a comprehensive first-principles theoretical study of the electronic and crystal structures of Ca1 -xLaxFeAs2 . After discussing the connection between the crystal structure of the 112 family, which Ca1 -xLaxFeAs2 is a member of, with the other known structures of Fe pnictide superconductors, we check the thermodynamic phase stability of CaFeAs2, and similar hyphothetical compounds SrFeAs2 and BaFeAs2 which, we find, are slightly higher in energy. We calculate the optical conductivity of Ca1 -xLaxFeAs2 using the DFT+DMFT method and predict a large in-plane resistivity anisotropy in the normal phase, which does not originate from electronic nematicity, but is enhanced by the electronic correlations. In particular, we predict a 0.34 eV peak in the y y component of the optical conductivity of the 30% La-doped compound, which corresponds to coherent interband transitions within a fast-dispersing band arising from the zigzag As chains, which are unique to this compound. We also study the Landau free energy for Ca1 -xLaxFeAs2 including the order parameter relevant for the nematic transition and find that the free energy does not have any extra terms that could induce ferro-orbital order. This explains why the presence of As chains does not broaden the nematic transition in Ca1 -xLaxFeAs2 .

  16. [Focal epithelial hyperplasia].

    Science.gov (United States)

    Vera-Iglesias, E; García-Arpa, M; Sánchez-Caminero, P; Romero-Aguilera, G; Cortina de la Calle, P

    2007-11-01

    Focal epithelial hyperplasia is a rare disease of the oral mucosa caused by the human papilloma virus (HPV). It appears as a benign epithelial growth, usually in the mucosa of the lower lip. It is mainly associated with HPV serotypes 13 and 32 and there is a clear racial predilection for the disease in Native Americans and Eskimos. We describe the case of a 17-year-old girl from Ecuador with multiple papular lesions in both lips that were clinically and histologically consistent with focal epithelial hyperplasia. Analysis by polymerase chain reaction detected HPV serotype 13.

  17. Focal and generalized alopecia.

    Science.gov (United States)

    O'Dair, H A; Foster, A P

    1995-07-01

    Focal or generalized alopecia is defined as hair loss affecting the ventral, lateral, perineal, and dorsal aspects of the trunk of the cat, usually in a symmetric pattern. This may be attributable to failure of hair coat production, excess loss of hair due to self trauma, or excess shedding of whole hairs. Self trauma is the most common cause of hair loss and is associated particularly with flea allergy dermatitis. Other causes of hair loss are reviewed.

  18. Proximal Focal Femoral Deficiency

    OpenAIRE

    Vishal Kalia, Vibhuti

    2008-01-01

    Proximal focal femoral deficiency (PFFD) is a developmental disorder of the proximal segment of thefemur and of acetabulum resulting in shortening of the affected limb and impairment of the function. It isa spectrum of congenital osseous anomalies characterized by a deficiency in the structure of the proximalfemur. The diagnosis is often made by radiological evaluation which includes identification and descriptionof PFFD and evaluation of associated limb anomalies by plain radiographs. Contra...

  19. Oral focal epithelial hyperplasia.

    Science.gov (United States)

    López-Jornet, Pía; Camacho-Alonso, Fabio; Berdugo, Lucero

    2010-01-01

    Focal epithelial hyperplasia (FEH) is a benign, asymptomatic disease. It appears as papules, principally on the lower lip, although it can also be found on the retro-commissural mucosa and tongue and, less frequently, on the upper lip, gingiva and palate. FEH is caused by human papillomavirus subtype 13 or 32. The condition occurs in many populations and ethnic groups. We present the clinical case of a 31-year-old male with lesions that clinically and histologically corresponded to FEH.

  20. Novel CCD image processor for Z-plane architecture

    Science.gov (United States)

    Kemeny, S. E.; Eid, E.-S.; Fossum, E. R.

    1989-09-01

    The use of charge-coupled device (CCD) circuits in Z-plane architectures for focal-plane image processing is discussed. The low-power, compact layout nature of CCDs makes them attractive for Z-plane application. Three application areas are addressed: non-uniformity compensation using CCD MDAC circuits, neighborhood image processing functions implemented with CCD circuits, and the use of CCDs for buffering multiple image frames. Such buffering enables spatial-temporal image transformation for lossless compression.

  1. Focal adhesions and assessment of cytotoxicity

    NARCIS (Netherlands)

    van Kooten, TG; Klein, CL; Wagner, M; Kirkpatrick, CJ

    1999-01-01

    Focal adhesions are highly ordered assemblies of transmembrane receptors, extracellular matrix proteins, and a large number of cytoplasmic proteins, including structural proteins, as well as tyrosine kinases, phosphatases, and their substrates. They are now accepted as a prime component of signal tr

  2. Focal cortical dysplasia - review.

    Science.gov (United States)

    Kabat, Joanna; Król, Przemysław

    2012-04-01

    Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults.Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed - from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized.Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe.Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes.New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life.Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias.THE MOST COMMON FINDINGS ON MRI IMAGING INCLUDE: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy.However, in type I cortical dysplasia, MR imaging is often normal, and also in both types

  3. Multi-focal multiphoton lithography.

    Science.gov (United States)

    Ritschdorff, Eric T; Nielson, Rex; Shear, Jason B

    2012-03-01

    Multiphoton lithography (MPL) provides unparalleled capabilities for creating high-resolution, three-dimensional (3D) materials from a broad spectrum of building blocks and with few limitations on geometry, qualities that have been key to the design of chemically, mechanically, and biologically functional microforms. Unfortunately, the reliance of MPL on laser scanning limits the speed at which fabrication can be performed, making it impractical in many instances to produce large-scale, high-resolution objects such as complex micromachines, 3D microfluidics, etc. Previously, others have demonstrated the possibility of using multiple laser foci to simultaneously perform MPL at numerous sites in parallel, but use of a stage-scanning system to specify fabrication coordinates resulted in the production of identical features at each focal position. As a more general solution to the bottleneck problem, we demonstrate here the feasibility for performing multi-focal MPL using a dynamic mask to differentially modulate foci, an approach that enables each fabrication site to create independent (uncorrelated) features within a larger, integrated microform. In this proof-of-concept study, two simultaneously scanned foci produced the expected two-fold decrease in fabrication time, and this approach could be readily extended to many scanning foci by using a more powerful laser. Finally, we show that use of multiple foci in MPL can be exploited to assign heterogeneous properties (such as differential swelling) to micromaterials at distinct positions within a fabrication zone.

  4. 大面阵CMOS快照模式焦平面读出电路设计分析%Analysis of Large Scale CMOS Snapshot Readout Circuit for Focal Plane Array

    Institute of Scientific and Technical Information of China (English)

    刘震宇; 赵建忠

    2008-01-01

    针对一款大面阵(640×512元)快照模式制冷型红外焦平面用的读出电路进行了初步分析验证.该读出电路采用改进DI结构,先积分后读出的积分控制模式,像素尺寸为25μm×25μm,芯片已在0.5μm双硅双铝(DPDM)标准CMOS工艺下试制.首先对该电路结构及工作原理进行分析,并对输入级等电路的传输特性进行仿真验证,最后给出探测器阵列与读出电路芯片互连后的测试结果.结果表明该读出电路适用于小像素、大规模的红外焦平面阵列.

  5. The mass fraction of AGN and the Fundamental Plane of black hole activity from a large X-ray selected sample of LINERs

    CERN Document Server

    Nisbet, D M

    2015-01-01

    A sample of 576 X-ray selected LINERs was constructed by combining data from the 3XMM-DR4 and SDSS-DR7 catalogues. The sample was used to investigate the fraction of galaxies hosting a LINER, finding that the fraction is a strong function of both stellar mass and black hole mass (scaling to the power of 1.6 +/- 0.2 and 0.6 +/- 0.1 respectively) and that it rises close to unity at the highest black hole masses and lowest X-ray luminosities. After obtaining radio flux densities from the FIRST survey, the sample was also used to investigate the Fundamental Plane of black hole activity - a scale-invariant relationship between black hole mass, X-ray luminosity and radio luminosity that is believed to hold across at least nine orders of magnitude of mass. There are key advantages in using only LINERs for the derivation as these are the counterparts of the "low-hard" X-ray binaries for which the relationship is tightest. The Fundamental Plane was found to be log (L_R / erg/s) = (0.65 +/- 0.07) log (L_X / 10^42 erg/s...

  6. 大芯径光谱传光光纤焦比退化特性研究%Focal Ratio Degradation of Large Core Spectrum Light-transmitting Optical Fiber

    Institute of Scientific and Technical Information of China (English)

    王森; 朱冰

    2011-01-01

    Ray tracing was used to analyze the Focal Ratio Degradation (FRD) properties of fibers, which is caused by the light transmitting in the fibers with offset and bending when we set the fibers and observe stars in astronomy. We analyzed and calculated the conditions of the fibers used in the Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST) according to the parameters of the fiber cables used in the LAMOST. These works provide useful reference in this project. According to the analysis and computation, the designed aim error of fibers should be less than 32 μm at least.The least bending radii is 300 mm when the fibers are installed for observation in the LAMOST projection.%针对天文光谱观测系统使用的传光光纤在布放和观测过程中因弯曲和入射中心未对准光纤中心而导致的焦比退化效应,采用光学追迹方法进行了分析计算.根据我国大天区面积多目标光纤光谱望远镜(LAMOST)工程中实际使用的光纤光缆的参数,分析并计算了所用传光光纤的使用条件,为工程应用提供参考.根据分析计算的结果,在LAMOST工程中光纤对准误差设计值为不大于32 μm的条件下,LAMOST工程中光纤光缆施工安装及观测使用过程中最小弯曲半径应限制在不小于300 mm.

  7. SMILE Microscopy : fast and single-plane based super-resolution volume imaging

    CERN Document Server

    Mondal, Partha Pratim

    2016-01-01

    Fast 3D super-resolution imaging is essential for decoding rapidly occurring biological processes. Encoding single molecules to their respective planes enable simultaneous multi-plane super-resolution volume imaging. This saves the data-acquisition time and as a consequence reduce radiation-dose that lead to photobleaching and other undesirable photochemical reactions. Detection and subsequent identification of the locus of individual molecule (both on the focal plane and off-focal planes) holds the key. Experimentally, this is achieved by accurate calibration of system PSF size and its natural spread in off-focal planes using sub-diffraction fluorescent beads. Subsequently the identification and sorting of single molecules that belong to different axial planes is carried out (by setting multiple cut-offs to respective PSFs). Simultaneous Multiplane Imaging based Localization Encoded (SMILE) microscopy technique eliminates the need for multiple z-plane scanning and thereby provides a truly simultaneous multip...

  8. Regulation of G protein-linked guanine nucleotide exchange factors for Rho, PDZ-RhoGEF, and LARG by tyrosine phosphorylation: evidence of a role for focal adhesion kinase.

    Science.gov (United States)

    Chikumi, Hiroki; Fukuhara, Shigetomo; Gutkind, J Silvio

    2002-04-05

    A recently identified family of guanine nucleotide exchange factors for Rho that includes PDZ-RhoGEF, LARG, and p115RhoGEF exhibits a unique structural feature consisting in the presence of area of similarity to regulators of G protein signaling (RGS). This RGS-like (RGL) domain provides a structural motif by which heterotrimeric G protein alpha subunits of the Galpha(12) family can bind and regulate the activity of RhoGEFs. Hence, these newly discovered RGL domain-containing RhoGEFs provide a direct link from Galpha(12) and Galpha(13) to Rho. Recently available data suggest, however, that tyrosine kinases can regulate the ability of G protein-coupled receptors (GPCRs) to stimulate Rho, although the underlying molecular mechanisms are still unknown. Here, we found that the activation of thrombin receptors endogenously expressed in HEK-293T cells leads to a remarkable increase in the levels of GTP-bound Rho within 1 min (11-fold) and a more limited but sustained activation (4-fold) thereafter, which lasts even for several hours. Interestingly, tyrosine kinase inhibitors did not affect the early phase of Rho activation, immediately after thrombin addition, but diminished the levels of GTP-bound Rho during the delayed phase. As thrombin receptors stimulate focal adhesion kinase (FAK) potently, we explored whether this non-receptor tyrosine kinase participates in the activation of Rho by GPCRs. We obtained evidence that FAK can be activated by thrombin, Galpha(12), Galpha(13), and Galpha(q) through both Rho-dependent and Rho-independent mechanisms and that PDZ-RhoGEF and LARG can in turn be tyrosine-phosphorylated through FAK in response to thrombin, thereby enhancing the activation of Rho in vivo. These data indicate that FAK may act as a component of a positive feedback loop that results in the sustained activation of Rho by GPCRs, thus providing evidence of the existence of a novel biochemical route by which tyrosine kinases may regulate the activity of Rho through

  9. Focal evolution induced by combination of nonspiral and spiral phase plates

    Institute of Scientific and Technical Information of China (English)

    Xiumin Gao; Jian Wang

    2007-01-01

    Focusing properties of Gaussian beam induced by nonspiral and spiral phase plates are investigated numerically. The nonspiral phase plate introduces phase singularity to the incident beam, and the spiral one adjusts the radial phase distribution. Intensity distributions in geometrical focal plane show that the parameters of phase plates can alter the intensity distributions considerably. And local dark focal spots may be obtained, the focal spot may evolve into a circle, a two-peak spot, or a curve line, which indicates that the combination of nonspiral and spiral phase plates can be used to form novel focal spots.

  10. Determinations of directions of the mean stress field in Sichuan-Yunnan region from a number of focal mechanism solutions

    Institute of Scientific and Technical Information of China (English)

    ZHONG Ji-mao; CHENG Wan-zheng

    2006-01-01

    Based on the spatial orientation and slip direction of the fault plane solutions, we present the expression of corresponding mechanical axis tensor in geographic coordinate system, and then put forward a method for calculating average mechanical axis tensor and its eigenvalues, which involves solving the corresponding eigenequation. The method for deducing mean stress field from T, B, and P axes parameters of a number of focal mechanism solutions has been verified by inverting data of mean stress fields in Fuyun region and in Tangshan region with fitting method of slip direction, and both results are consistent. To study regional average stress field, we need to choose a population of focal mechanism solutions of earthquakes in the massifs where there are significant tectonic structures. According to the focal mechanism solutions of 256 moderate-strong earthquakes occurred in 13 seismic zones of Sichuan-Yunnan region, the quantitative analysis results of stress tensor in each seismic zone have been given. The algorithm of such method is simple and convenient, which makes the method for analyzing tectonic stress field with large amount of focal mechanism solution data become quantified.

  11. Systemic focal epileptogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Remler, M.P.; Marcussen, W.H.

    1986-01-01

    Rats that receive radiation to 0.25 cc of one cerebral hemisphere are clinically and electroencephalographically normal until there is a breakdown of the blood-brain barrier (BBB) at 3 to 6 months postradiation. This BBB lesion can be detected by transient focal seizure activity produced by the BBB-excluded systemic convulsant bicuculline methiodide. In two rats the seizure activity induced by this one injection was self-sustaining. In seven of 15 other rats tested, the subsequent administration of repeated 2 mg/kg injections created a chronic focus that continued to spike with great frequency for 3 weeks or more without further administration of any convulsant. In three of eight other rats, implanted minipumps delivering 180 micrograms/h of bicuculline methiodide produced self-sustaining epileptic activity.

  12. Focal femoral condyle resurfacing.

    LENUS (Irish Health Repository)

    Brennan, S A

    2013-03-01

    Focal femoral inlay resurfacing has been developed for the treatment of full-thickness chondral defects of the knee. This technique involves implanting a defect-sized metallic or ceramic cap that is anchored to the subchondral bone through a screw or pin. The use of these experimental caps has been advocated in middle-aged patients who have failed non-operative methods or biological repair techniques and are deemed unsuitable for conventional arthroplasty because of their age. This paper outlines the implant design, surgical technique and biomechanical principles underlying their use. Outcomes following implantation in both animal and human studies are also reviewed. Cite this article: Bone Joint J 2013;95-B:301-4.

  13. Extensive focal epithelial hyperplasia.

    Science.gov (United States)

    Hashemipour, Maryam Alsadat; Shoryabi, Ali; Adhami, Shahrzad; Mehrabizadeh Honarmand, Hoda

    2010-01-01

    Heck's disease or focal epithelial hyperplasia is a benign contagious disease caused by human papillomavirus types 13 or 32. It occurs with low frequency in the Iranian population. This condition is characterized by the occurrence of multiple, small papules or nodules in the oral cavity, especially on the labial and buccal mucosa and tongue. In some populations, up to 39% of children are affected. Conservative surgical excision of lesions may be performed for diagnostic or aesthetic purposes. The risk of recurrence after this therapy is minimal, and there seems to be no malignant transformation potential. In the present work, we presented the clinical case of a 12-year-old Iranian girl with oral lesions that clinically and histologically correspond to Heck's disease.

  14. Proximal Focal Femoral Deficiency

    Directory of Open Access Journals (Sweden)

    Vishal Kalia, Vibhuti

    2008-01-01

    Full Text Available Proximal focal femoral deficiency (PFFD is a developmental disorder of the proximal segment of thefemur and of acetabulum resulting in shortening of the affected limb and impairment of the function. It isa spectrum of congenital osseous anomalies characterized by a deficiency in the structure of the proximalfemur. The diagnosis is often made by radiological evaluation which includes identification and descriptionof PFFD and evaluation of associated limb anomalies by plain radiographs. Contrast arthrography orMagnetic Resonance Imaging is indicated when radiological features are questionable and to disclose thepresence and location of the femoral head and any cartilagenous anlage. The disorder is more commonlyunilateral and is apparent at birth. However, bilateral involvement is rarely seen. Therapy of the disorder isdirected towards satisfactory ambulation and specific treatment depending on the severity of dysplasia.

  15. Relative Motion between the Rivera and North American Plates: Constraints from Focal Mechanisms

    Science.gov (United States)

    Suárez, Gerardo; Jaramillo, Said H.; Bandy, William

    2010-05-01

    The direction and velocity of the Rivera Plate in western Mexico relative to the North American plate has been a source of controversy. The southeastern segment of this plate boundary has been the site of one of the largest subduction events observed in Mexico during the last 100 years: the 3 June 1932 earthquake (Mw 8.2). To the northwest of the rupture zone of the 1932 event, however, there are no other known large subduction events, either from the historical or instrumental record. We analyze all focal mechanisms in this northern segment of the plate boundary to define the direction of relative motion between these two plates. The largest event occurred beneath the Tres Marias Escarpment, the earthquake of 4 December 1948. The recomputed magnitude yields Mw 6.4. This event caused widespread damage in a penal colony on the Tres Marias Islands. Although the focal mechanism of the 1948 event is not well constrained, the first arrival data collected shows reverse faulting with P axes oriented in a NE-SW direction. This mechanism coincides with other two fault plane solutions of more recent events. These mechanisms indicate reverse faulting beneath the Tres Marias Escarpment. To the northwest of the Islas Marias, in area where no clear physiographic feature defines the plate limits, we identify a group of strike-slip events, where the E-W trending nodal plane indicates right-lateral motion. These mechanisms suggest that the relative motion between Rivera and North America may be taken up by right-lateral strike slip motion. The accuracy of the locations does not allow to define in detail the geometry of this plate boundary. The slip vectors determined from these focal mechanisms are compared with the flow lines resulting from the various poles of relative motion between Rivera and North America to constrain its location.

  16. Atypical focal nodular hyperplasia of the liver

    Institute of Scientific and Technical Information of China (English)

    Muhammad Rizwan Khan; Taimur Saleem; Tanveer Ul Haq; Kanwal Aftab

    2011-01-01

    BACKGROUND: Focal nodular hyperplasia, a benign hepatic tumor, is usually asymptomatic. However, rarely the entity can cause symptoms, mandating intervention. METHOD: We present a case of focal nodular hyperplasia of the liver, which caused a considerable diagnostic dilemma due to its atypical presentation. RESULTS: A 29-year-old woman presented with a 15-year history of a progressively increasing mass in the right upper quadrant which was associated with pain and emesis. Examination showed a firm, mobile mass palpable below the right subcostal margin. A computed tomography scan of the abdomen showed an exophytic mass arising from hepatic segments III and IVb. Trucut biopsy of the hepatic mass was equivocal. Angiography showed a vascular tumor that was supplied by a tortuous branch of the proper hepatic artery. Surgical intervention for removal of the mass was undertaken. Intra-operatively, two large discrete tumors were found and completely resected. Histopathological examination showed features consistent with focal nodular hyperplasia. CONCLUSION: This description of an unusual case of focal nodular hyperplasia of the liver highlights the point that the diagnosis of otherwise benign hepatic tumors may be difficult despite extensive work-up in some cases.

  17. Statistical earthquake focal mechanism forecasts

    CERN Document Server

    Kagan, Yan Y

    2013-01-01

    Forecasts of the focal mechanisms of future earthquakes are important for seismic hazard estimates and Coulomb stress and other models of earthquake occurrence. Here we report on a high-resolution global forecast of earthquake rate density as a function of location, magnitude, and focal mechanism. In previous publications we reported forecasts of 0.5 degree spatial resolution, covering the latitude range magnitude, and focal mechanism. In previous publications we reported forecasts of 0.5 degree spatial resolution, covering the latitude range from -75 to +75 degrees, based on the Global Central Moment Tensor earthquake catalog. In the new forecasts we've improved the spatial resolution to 0.1 degree and the latitude range from pole to pole. Our focal mechanism estimates require distance-weighted combinations of observed focal mechanisms within 1000 km of each grid point. Simultaneously we calculate an average rotation angle between the forecasted mechanism and all the surrounding mechanisms, using the method ...

  18. Molecular Mechanisms of Mechanosensitivity in Focal Adhesions

    OpenAIRE

    2016-01-01

    Physical environment guides tissue regeneration and morphology in both health and disease. In the past three decades, several experiments illustrated that mechanical cues are captured and transduced to biochemical signals in the cellular level (mechanotransduction) mediated by cell adhesion. Cells adhere to their microenvironment through large protein assemblies known as focal adhesions that directly couple intra- and extra-cellular matrices and play a critical role in many vital cell functio...

  19. Dominant fault plane orientations of intermediate-depth earthquakes beneath South America

    Science.gov (United States)

    Warren, Linda M.

    2014-07-01

    The South American subduction zone exhibits considerable variation: the subduction angle alternates between flat and steep; the subducting plate has complex structures; and arc volcanism in the overlying plate has gaps. I investigate the effect of these differences in incoming plate structure and slab geometry on intermediate-depth earthquakes, specifically their fault orientations and rupture characteristics, and find that slab geometry has the largest impact on fault orientation. I use rupture directivity to estimate rupture direction and rupture velocity and to distinguish the fault plane from the auxiliary plane of the focal mechanism. From analysis of 163 large (Mw≥5.7) intermediate-depth (60-360 km depth) earthquakes from along the length of South America, estimated rupture azimuths and plunges show no trends, appearing to be randomly distributed on the determined population of fault plane orientations, and a majority of earthquakes are made up of multiple subevents. As seen in other subduction zones, subduction segments descending at normal angles have predominantly subhorizontal faults. Flat slab segments also have a dominant fault orientation, but those earthquakes slip along the conjugate nodal plane of the focal mechanism. In strongly curved slab segments, such as at the downdip edge of flat segments where the slab resubducts, earthquakes may slip along either nodal plane orientation. While both fault orientations could be consistent with the reactivation of fossil outer rise faults, the fault orientations are also consistent with expectations for newly created faults in agreement with the ambient stress field. Fault reactivation alone does not explain why different fault orientations are active in segments with different geometries, so the preferred explanation for having regionally consistent fault orientations is that they minimize the total work of the system. The previously observed predominance of subhorizontal faults appears to be a consequence

  20. Plane-polar Fresnel and far-field computations using the Fresnel-Wilcox and Jacobi-Bessel expansions. [for large aperture antennas

    Science.gov (United States)

    Rahmat-Samii, Y.; Galindo-Israel, V.

    1981-01-01

    It is pointed out that the computation of the Fresnel fields for large aperture antennas is significant for many applications. The present investigation is concerned with an approach for the effective utilization of the coefficients of the Jacobi-Bessel series for the far-field to obtain an analytically continuous representation of the antenna field which is valid from the Fresnel region into the far field. Attention is given to exact formulations and closed form solutions, Fresnel and Fresnel small angle approximations, aspects of field expansion, the accuracy of the Fresnel and Fresnel small angle approximations, and the Jacobi-Bessel expansion applied to the Fresnel small angle approximation.

  1. Fourier plane image amplifier

    Science.gov (United States)

    Hackel, L.A.; Hermann, M.R.; Dane, C.B.; Tiszauer, D.H.

    1995-12-12

    A solid state laser is frequency tripled to 0.3 {micro}m. A small portion of the laser is split off and generates a Stokes seed in a low power oscillator. The low power output passes through a mask with the appropriate hole pattern. Meanwhile, the bulk of the laser output is focused into a larger stimulated Brillouin scattering (SBS) amplifier. The low power beam is directed through the same cell in the opposite direction. The majority of the amplification takes place at the focus which is the fourier transform plane of the mask image. The small holes occupy large area at the focus and thus are preferentially amplified. The amplified output is now imaged onto the multichip module where the holes are drilled. Because of the fourier plane amplifier, only about 1/10th the power of a competitive system is needed. This concept allows less expensive masks to be used in the process and requires much less laser power. 1 fig.

  2. The MOND Fundamental Plane

    CERN Document Server

    Cardone, V F; Diaferio, A; Tortora, C; Molinaro, R

    2010-01-01

    Modified Newtonian Dynamics (MOND) has been shown to be able to fit spiral galaxy rotation curves as well as giving a theoretical foundation for empirically determined scaling relations, such as the Tully - Fisher law, without the need for a dark matter halo. As a complementary analysis, one should investigate whether MOND can also reproduce the dynamics of early - type galaxies (ETGs) without dark matter. As a first step, we here show that MOND can indeed fit the observed central velocity dispersion $\\sigma_0$ of a large sample of ETGs assuming a simple MOND interpolating functions and constant anisotropy. We also show that, under some assumptions on the luminosity dependence of the Sersic n parameter and the stellar M/L ratio, MOND predicts a fundamental plane for ETGs : a log - linear relation among the effective radius $R_{eff}$, $\\sigma_0$ and the mean effective intensity $\\langle I_e \\rangle$. However, we predict a tilt between the observed and the MOND fundamental planes.

  3. Fourier plane image amplifier

    Science.gov (United States)

    Hackel, Lloyd A.; Hermann, Mark R.; Dane, C. Brent; Tiszauer, Detlev H.

    1995-01-01

    A solid state laser is frequency tripled to 0.3 .mu.m. A small portion of the laser is split off and generates a Stokes seed in a low power oscillator. The low power output passes through a mask with the appropriate hole pattern. Meanwhile, the bulk of the laser output is focused into a larger stimulated Brillouin scattering (SBS) amplifier. The low power beam is directed through the same cell in the opposite direction. The majority of the amplification takes place at the focus which is the fourier transform plane of the mask image. The small holes occupy large area at the focus and thus are preferentially amplified. The amplified output is now imaged onto the multichip module where the holes are drilled. Because of the fourier plane amplifier, only .about.1/10th the power of a competitive system is needed. This concept allows less expensive masks to be used in the process and requires much less laser power.

  4. Fixed Sagittal Plane Imbalance

    OpenAIRE

    Savage, Jason W.; Patel, Alpesh A.

    2014-01-01

    Study Design Literature review. Objective To discuss the evaluation and management of fixed sagittal plane imbalance. Methods A comprehensive literature review was performed on the preoperative evaluation of patients with sagittal plane malalignment, as well as the surgical strategies to address sagittal plane deformity. Results Sagittal plane imbalance is often caused by de novo scoliosis or iatrogenic flat back deformity. Understanding the etiology and magnitude of sagittal malalignment is ...

  5. FOCAL MOTOR SEIZURES WITH TYPICAL AUTOMATISMS (FOCAL AUTOMOTOR SEIZURES

    Directory of Open Access Journals (Sweden)

    M. B. Mironov

    2014-01-01

    Full Text Available The paper deals with the study of a group of patients with focal automotor seizures, by taking into consideration their nosological, anamnestic, clinical, electroencephalographic, and neuroimaging features.

  6. Distributed storage in the plane

    NARCIS (Netherlands)

    Altman, Eitan; Avrachenkov, Konstatin; Goseling, Jasper

    2013-01-01

    We consider storage devices located in the plane according to a general point process and specialize the results for the homogeneous Poisson process. A large data file is stored at the storage devices, which have limited storage capabilities. Hence, they can only store parts of the data. Clients can

  7. Distributed storage in the plane

    NARCIS (Netherlands)

    Altman, Eitan; Avrachenkov, Konstatin; Goseling, Jasper

    2014-01-01

    We consider storage devices located in the plane according to a general point process and specialize the results for the homogeneous Poisson process. A large data file is stored at the storage devices, which have limited storage capabilities. Hence, they can only store parts of the data. Clients can

  8. Distributed storage in the plane

    NARCIS (Netherlands)

    Altman, Eitan; Avrachenkov, Konstatin; Goseling, Jasper

    2013-01-01

    We consider storage devices located in the plane according to a general point process and specialize the results for the homogeneous Poisson process. A large data file is stored at the storage devices, which have limited storage capabilities. Hence, they can only store parts of the data. Clients can

  9. Distributed storage in the plane

    NARCIS (Netherlands)

    Altman, Eitan; Avrachenkov, Konstatin; Goseling, Jasper

    2014-01-01

    We consider storage devices located in the plane according to a general point process and specialize the results for the homogeneous Poisson process. A large data file is stored at the storage devices, which have limited storage capabilities. Hence, they can only store parts of the data. Clients can

  10. Tunable focalizers: axicons, lenses, and axilenses

    Science.gov (United States)

    Ojeda-Castañeda, Jorge; Gómez-Sarabia, Cristina M.; Ledesma, Sergio

    2013-09-01

    We propose the use of a pair of phase masks, which have both radial and angular variations, for implementing several varifocal devices. One mask of the proposed pair has a complex amplitude transmittance that is the complex conjugate of the other member of the pair. We show that the overall complex amplitude transmittance has only a radial variation after introducing an in-plane rotation, say by an angle β, between the members of the pair. However, we note that the optical power is proportional to the rotation angle β. As examples of the proposed method, we show that the refractive pair is useful for implementing varifocal lenses, tunable axicons, controllable axilenses, as well as annularly distributed focalizers.

  11. Genetics Home Reference: focal dermal hypoplasia

    Science.gov (United States)

    ... Home Health Conditions focal dermal hypoplasia focal dermal hypoplasia Enable Javascript to view the expand/collapse boxes. ... PDF Open All Close All Description Focal dermal hypoplasia is a genetic disorder that primarily affects the ...

  12. Azimuthal diffusion of the large-scale-circulation plane, and absence of significant non-Boussinesq effects, in turbulent convection near the ultimate-state transition

    CERN Document Server

    He, Xiaozhou; Ahlers, Guenter

    2016-01-01

    We present measurements of the orientation $\\theta_0$ and temperature amplitude $\\delta$ of the large-scale circulation in a cylindrical sample of turbulent Rayleigh-Benard convection (RBC) with aspect ratio $\\Gamma \\equiv D/L = 1.00$ ($D$ and $L$ are the diameter and height respectively) and for the Prandtl number $Pr \\simeq 0.8$. Results for $\\theta_0$ revealed a preferred orientation with upflow in the West, consistent with a broken azimuthal invariance due to Earth's Coriolis force [see \\cite{BA06b}]. They yielded the azimuthal diffusivity $D_\\theta$ and a corresponding Reynolds number $Re_{\\theta}$ for Rayleigh numbers over the range $2\\times 10^{12} < Ra < 1.5\\times 10^{14}$. In the classical state ($Ra < 2\\times 10^{13}$) the results were consistent with the measurements by \\cite{BA06a} for $Ra < 10^{11}$ and $Pr = 4.38$ which gave $Re_{\\theta} \\propto Ra^{0.28}$, and with the Prandtl-number dependence $Re_{\\theta} \\propto Pr^{-1.2}$ as found previously also for the velocity-fluctuation Rey...

  13. An empirical assessment of the focal species hypothesis.

    Science.gov (United States)

    Lindenmayer, D B; Lane, P W; Westgate, M J; Crane, M; Michael, D; Okada, S; Barton, P S

    2014-12-01

    Biodiversity surrogates and indicators are commonly used in conservation management. The focal species approach (FSA) is one method for identifying biodiversity surrogates, and it is underpinned by the hypothesis that management aimed at a particular focal species will confer protection on co-occurring species. This concept has been the subject of much debate, in part because the validity of the FSA has not been subject to detailed empirical assessment of the extent to which a given focal species actually co-occurs with other species in an assemblage. To address this knowledge gap, we used large-scale, long-term data sets of temperate woodland birds to select focal species associated with threatening processes such as habitat isolation and loss of key vegetation attributes. We quantified co-occurrence patterns among focal species, species in the wider bird assemblage, and species of conservation concern. Some, but not all, focal species were associated with high levels of species richness. One of our selected focal species was negatively associated with the occurrence of other species (i.e., it was an antisurrogate)-a previously undescribed property of nominated focal species. Furthermore, combinations of focal species were not associated with substantially elevated levels of bird species richness, relative to levels associated with individual species. Our results suggest that although there is some merit to the underpinning concept of the FSA, there is also a need to ensure that actions are sufficiently flexible because management tightly focused on a given focal species may not benefit some other species, including species of conservation concern, such of which might not occur in species-rich assemblages. © 2014 Society for Conservation Biology.

  14. The computed cranial focal point

    NARCIS (Netherlands)

    Jong, G.A. de; Maal, T.J.J.; Delye, H.

    2015-01-01

    INTRODUCTION: Stereophotogrammetry is a radiation-free method for monitoring skull development after craniosynostosis repair. Lack of clear fixed reference points complicate longitudinal comparison of 3D photographs. Therefore we developed the 'computed cranial focal point' (CCFP). METHODS: The CCFP

  15. Traceability of high focal length cameras with diffractive optical elements

    Science.gov (United States)

    Lages Martins, L.; Silva Ribeiro, A.; Sousa, J. Alves e.

    2016-11-01

    This paper describes the use of diffractive optical elements (DOEs) for metrological traceable geometrical testing of high focal length cameras applied in the observation of large- scale structures. DOEs and related mathematical models are briefly explained. Laboratorial activities and results are described for the case of a high focal length camera used for longdistance displacement measurement of a long-span (2278 m) suspension bridge.

  16. Fault plane orientations of intermediate-depth earthquakes in the Middle America Trench

    Science.gov (United States)

    Warren, Linda M.; Langstaff, Meredith A.; Silver, Paul G.

    2008-01-01

    Intermediate-depth earthquakes are often attributed to dehydration embrittlement reactivating preexisting weak zones. The orientation of presubduction faults is particularly well known offshore of Middle America, where seismic reflection profiles show outer rise faults dipping toward the trench and extending >20 km into the lithosphere. If water is transported along these faults and incorporated into hydrous minerals, the faults may be reactivated later when the minerals dehydrate. In this case, the fault plane orientations should be the same in the outer rise and at depth, after accounting for the angle of subduction. To test this hypothesis, we analyze the directivity of 54 large (MW ≥ 5.7) earthquakes between 35 and 220 km depth in the Middle America Trench. For 12 of these earthquakes, the directivity vector allows us to identify the fault plane of the focal mechanism. Between 35 and 85 km depth, we observe both subhorizontal and subvertical fault planes. The subvertical fault planes are consistent with the reactivation of outer rise faults, whereas the subhorizontal fault planes suggest the formation of new faults. Deeper than 85 km, we only observe subhorizontal faults, indicating that the outer rise faults are no longer being reactivated. The similarity with previous results from the colder Tonga-Kermadec subduction zone suggests that the mechanism generating these earthquakes, and controlling fault plane orientations, depends on pressure rather than temperature or other tectonic parameters and that the observed rupture characteristics constitute a basic feature of intermediate-depth seismicity. Exclusively subhorizontal faults may result from isobaric rupture propagation or the hindrance of seismic slip on preexisting weak subvertical planes.

  17. Large magnetoresistance in current-perpendicular-to-plane pseudo spin-valves using Co{sub 2}Fe(Ga{sub 0.5}Ge{sub 0.5}) Heusler alloy and AgZn spacer

    Energy Technology Data Exchange (ETDEWEB)

    Du, Ye; Hono, K. [Magnetic Materials Unit, National Institute for Materials Science, Tsukuba 305-0047 (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571 (Japan); Furubayashi, T.; Sasaki, T. T.; Sakuraba, Y.; Takahashi, Y. K. [Magnetic Materials Unit, National Institute for Materials Science, Tsukuba 305-0047 (Japan)

    2015-09-14

    Fully epitaxial pseudo spin-valves (PSVs) using 10-nm-thick Co{sub 2}Fe(Ga{sub 0.5}Ge{sub 0.5}) (CFGG) ferromagnetic layers and a 5-nm-thick AgZn space layer annealed at 630 °C show a large current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) output with resistance-change area product, ΔRA, of 21.5 mΩ μm{sup 2} and MR ratio of 59.6% at room temperature. These values are substantially enhanced to ΔRA of 59.8 mΩ μm{sup 2} and MR ratio of 200.0% at 10 K. The large MR is attributed to the high spin polarization of the CFGG electrodes with the enhanced L2{sub 1} ordering induced by the atomic diffusion of Zn through the CFGG layers. The CPP-PSV shows relatively large ΔRA of 10.9 mΩ μm{sup 2} with the MR ratio of 25.6% for the low annealing temperature of 350 °C, which is a practically useful feature for read sensor applications.

  18. A novel Region of Interest (ROI) imaging technique for biplane imaging in interventional suites: high-resolution small field-of-view imaging in the frontal plane and dose-reduced, large field-of-view standard-resolution imaging in the lateral plane

    Science.gov (United States)

    Swetadri Vasan, Setlur Nagesh; Ionita, C.; Bednarek, D. R.; Rudin, Stephen

    2014-03-01

    Endovascular-Image-Guided-Interventional (EIGI) treatment of neuro-vascular conditions such as aneurysms, stenosed arteries, and vessel thrombosis make use of treatment devices such as stents, coils, and balloons which have very small feature sizes, 10's of microns to a few 100's of microns, and hence demand a high resolution imaging system. The current state-of-the-art flat panel detector (FPD) has about a 200-um pixel size with the Nyquist of 2.5 lp/mm. For higher-resolution imaging a charge-coupled device (CCD) based Micro-Angio - Fluoroscope (MAF-CCD) with a pixel size of 35um (Nyquist of 11 lp/mm) was developed and previously reported. Although the detector addresses the high resolution needs, the Field-Of-View (FOV) is limited to 3.5 cm x 3.5 cm, which is much smaller than current FPDs. During the use of the MAF-CCD for delicate parts of the intervention, it may be desirable to have real-time monitoring outside the MAF FOV with a low dose, and lower, but acceptable, quality image. To address this need, a novel imaging technique for biplane imaging systems has been developed, using an MAFCCD in the frontal plane and a dose-reduced standard large FOV imager in the lateral plane. The dose reduction is achieved by using a combination of ROI fluoroscopy and spatially different temporal filtering, a technique that has been previously presented. In order to evaluate this technique, a simulation using images acquired during an actual EIGI treatment on a patient, followed by an actual implementation on phantoms is presented.

  19. Focal Conic Flower Textures at Curved Interfaces

    Directory of Open Access Journals (Sweden)

    Daniel A. Beller

    2013-12-01

    Full Text Available Focal conic domains (FCDs in smectic-A liquid crystals have drawn much attention, both for their exquisitely structured internal form and for their ability to direct the assembly of micromaterials and nanomaterials in a variety of patterns. A key to directing FCD assembly is control over the eccentricity of the domain. Here, we demonstrate a new paradigm for creating spatially varying FCD eccentricity by confining a hybrid-aligned smectic with curved interfaces. In particular, we manipulate interface behavior with colloidal particles in order to experimentally produce two examples of what has recently been dubbed the flower texture [C. Meyer et al., Focal Conic Stacking in Smectic A Liquid Crystals: Smectic Flower and Apollonius Tiling, Materials 2, 499, 2009MATEG91996-194410.3390/ma2020499], where the focal hyperbolæ diverge radially outward from the center of the texture, rather than inward as in the canonical éventail or fan texture. We explain how this unconventional assembly can arise from appropriately curved interfaces. Finally, we present a model for this system that applies the law of corresponding cones, showing how FCDs may be embedded smoothly within a “background texture” of large FCDs and concentric spherical layers, in a manner consistent with the qualitative features of the smectic flower. Such understanding could potentially lead to disruptive liquid-crystal technologies beyond displays, including patterning, smart surfaces, microlens arrays, sensors, and nanomanufacturing.

  20. Recovery of Deep Moonquake Focal Mechanisms

    Science.gov (United States)

    Weber, Renee C.; Knapmeyer, Martin

    2012-01-01

    Deep moonquakes are clustered not only in space but also in time: their recurrence times correspond to the durations of the anomalistic and draconic months, with some clusters preferring one of the two periods, while others are active with both periods. A key constraint for the understanding of the connection between the orbital motion of the Moon and its seismic activity is the focal mechanism: the orientation of the fault surface on which failure occurs during the quake. Due to the small aperture of the Apollo seismic network and the strong scattering of seismic waves within the lunar crust, the evaluation of P wave first motions to constrain the strike and dip of the fault planes is not feasible. Instead we evaluate the amplitude ratios of P and S waves. Seismograms are rotated into the P-SV-SH coordinate frame and amplitudes are determined as averages over short time windows after the arrival to reduce the impact of the scattering coda, which is independent of the source orientation. We allow for reversals of the fault motion, as observed for some clusters in previous studies, by taking into account the absolute amplitude only, without sign. An empirical site correction factor is applied to correct for amplitude distortions in the crust. We construct ensembles of fault plane solutions using an exhaustive grid search by accepting all orientations that reproduce the measured amplitude ratios within the observed standard deviations. Since all events of a given cluster are supposed to share the same fault plane, the combination of the individual inversion results further constrains the orientation. We evaluate 106 events from 25 different moonquake clusters. The most active cluster A001 contributes 37 events, while others contribute 1 to 9 events per cluster. Comparison of fault orientations with the variation of the tidal stress results in preferred orientations.

  1. Deep Earthquake Mechanics Inferred From Fault-Plane Orientations in Central South America

    Science.gov (United States)

    Warren, L. M.; Biryol, C. B.; Beck, S. L.

    2007-12-01

    To place constraints on the physical mechanisms of deep earthquakes, we analyze the rupture properties of >30 intraslab earthquakes with MW >5.7 in central South America (15°--25°S). For all earthquakes, we perform a directivity analysis to estimate the rupture vector and identify the fault plane. After comparing the results with synthetics, we can distinguish the fault plane of the focal mechanism for ~1/3 of these earthquakes. For the largest earthquakes, we also invert for the slip distribution on the fault plane. At intermediate depths, we test whether earthquakes result from dehydration embrittlement reactivating the steep, trenchward-dipping faults of the outer rise. After accounting for the angle of subduction, these faults would be approximately vertical. This prediction contrasts with the orientation of faults identified between 100--300 km depth, which are all subhorizontal and instead suggest the creation of a new system of faults. The exclusive occurrence of subhorizontal faults agrees with previous studies in the Tonga-Kermadec and Middle America subduction zones. The similarity in results between the three subduction zones despite large differences in temperature, subduction velocity, and subduction angle suggests that the earthquake-generating mechanism is controlled by pressure rather than tectonic parameters. Deeper than 300 km, earthquakes occur along both subhorizontal and subvertical fault planes.

  2. Super-oscillatory focusing of circularly polarized light by ultra-long focal length planar lens based on binary amplitude-phase modulation

    Science.gov (United States)

    Chen, Gang; Li, Yuyan; Yu, Anping; Wen, Zhongquan; Dai, Luru; Chen, Li; Zhang, Zhihai; Jiang, Senlin; Zhang, Kun; Wang, Xianyou; Lin, Feng

    2016-06-01

    In traditional optics, the focal spot size of a conventional lens is restricted to the diffraction limit 0.5λ/NA, where λ is the wavelength in vacuum and NA is the numerical aperture of the lens. Recently, various sub-diffraction focusing optical devices have been demonstrated, but they usually have short focal length and high numerical aperture. Moreover, they always suffer the problem of huge sidelobes near the focal spot and small field of view, especially when the focal spot size is less than the super-oscillation criteria 0.38λ/NA. To address the problem, here, we reported a far-field sub-diffraction point-focusing lens based on binary phase and amplitude modulation with ultra-long focal length 252.8 μm (399.5λ) and small numerical aperture 0.78, and experimentally demonstrated a super-oscillatory focusing of circularly polarized light with spot size 287 nm (0.454λ), smaller than the diffraction limit 0.64λ and the super-oscillation criterion 0.487λ. What’s more, on the focal plane, in the measured area within the radius of 142λ, the largest sidelobe intensity is less than 26% of the central lobe intensity. Such ultra-long distance super-oscillatory focusing with small sidelobes and large field of view has great potential applications in far-field super-resolution microscopy, ultra-high-density optical storage and nano-fabrication.

  3. Super-oscillatory focusing of circularly polarized light by ultra-long focal length planar lens based on binary amplitude-phase modulation.

    Science.gov (United States)

    Chen, Gang; Li, Yuyan; Yu, Anping; Wen, Zhongquan; Dai, Luru; Chen, Li; Zhang, Zhihai; Jiang, Senlin; Zhang, Kun; Wang, Xianyou; Lin, Feng

    2016-06-29

    In traditional optics, the focal spot size of a conventional lens is restricted to the diffraction limit 0.5λ/NA, where λ is the wavelength in vacuum and NA is the numerical aperture of the lens. Recently, various sub-diffraction focusing optical devices have been demonstrated, but they usually have short focal length and high numerical aperture. Moreover, they always suffer the problem of huge sidelobes near the focal spot and small field of view, especially when the focal spot size is less than the super-oscillation criteria 0.38λ/NA. To address the problem, here, we reported a far-field sub-diffraction point-focusing lens based on binary phase and amplitude modulation with ultra-long focal length 252.8 μm (399.5λ) and small numerical aperture 0.78, and experimentally demonstrated a super-oscillatory focusing of circularly polarized light with spot size 287 nm (0.454λ), smaller than the diffraction limit 0.64λ and the super-oscillation criterion 0.487λ. What's more, on the focal plane, in the measured area within the radius of 142λ, the largest sidelobe intensity is less than 26% of the central lobe intensity. Such ultra-long distance super-oscillatory focusing with small sidelobes and large field of view has great potential applications in far-field super-resolution microscopy, ultra-high-density optical storage and nano-fabrication.

  4. Characterization of the time-dependent strain field at seismogenic depths using first-motion focal mechanisms: Observations of large-scale decadal variations in stress along the San Andrea fault system

    Science.gov (United States)

    Sipkin, S.A.; Silver, P.G.

    2003-01-01

    We present a method for summing moment tensors derived from first-motion focal mechanisms to study temporal dependence in features of the subsurface regional strain field. Time-dependent processes are inferred by comparing mechanisms summed over differing time periods. We apply this methodology to seismogenic zones in central and southern California using focal mechanisms produced by the Northern and Southern California Seismograph Networks for events during 1980-1999. We find a consistent pattern in both the style of deformation (strike-slip versus compressional) and seismicity rate across the entire region. If these temporal variations are causally related, it suggests a temporal change in the regional-scale stress field. One change consistent with the observations is a rotation in the regional maximum horizontal compressive stress direction, followed by a reversal to the original direction. Depending upon the dominant style of deformation locally, this change in orientation of the regional stress will tend to either enhance or hinder deformation. The mode of enhanced deformation can range from increased microseismicity and creep to major earthquakes. We hypothesize that these temporal changes in the regional stress field are the result of subtle changes in apparent relative plate motion between the Pacific and North American plates, perhaps due to long-range postseismic stress diffusion. Others have hypothesized that small changes in plate motion over thousands of years, and/or over decades, are responsible for changes in the style of deformation in southern California. We propose that such changes, over the course of just a few years, also affect the style of deformation.

  5. Grupo Focal em Pesquisas Sociais

    OpenAIRE

    Maria Lúcia Silva Servo; Pricila Oliveira Araújo

    2012-01-01

    Este artigo tem como objetivo discutir a técnica de grupo focal em pesquisas sociais. Apresenta-se as concepções sobre grupo focal. Traz-se os postulados de Pichon-Rivière sobre grupo operativo, os instrumentos de planificação, os vetores do campo grupal para nortear a dinâmica e a observação do campo grupal, bem como a organização, a operacionalização e a análise dos dados das sessões de grupo focal. Através desta técnica de coleta de dados em pesquisas sociais, é possível a construção do EC...

  6. Grupo Focal em Pesquisas Sociais

    OpenAIRE

    Maria Lúcia Silva Servo; Pricila Oliveira Araújo

    2012-01-01

    Este artigo tem como objetivo discutir a técnica de grupo focal em pesquisas sociais. Apresenta-se as concepções sobre grupo focal. Traz-se os postulados de Pichon-Rivière sobre grupo operativo, os instrumentos de planificação, os vetores do campo grupal para nortear a dinâmica e a observação do campo grupal, bem como a organização, a operacionalização e a análise dos dados das sessões de grupo focal. Através desta técnica de coleta de dados em pesquisas sociais, é possível a construção do EC...

  7. Single-plane multiple speckle pattern phase retrieval using a deformable mirror

    DEFF Research Database (Denmark)

    Almoro, Percival F.; Glückstad, Jesper; Hanson, Steen Grüner

    2010-01-01

    A design for a single-plane multiple speckle pattern phase retrieval technique using a deformable mirror (DM) is analyzed within the formalism of complex ABCD-matrices, facilitating its use in conjunction with dynamic wavefronts. The variable focal length DM positioned at a Fourier plane of a lens...

  8. Large Binocular Telescope Project

    Science.gov (United States)

    Hill, John M.

    1997-03-01

    The large binocular telescope (LBT) project have evolved from concepts first proposed in 1985. The present partners involved in the design and construction of this 2 by 8.4 meter binocular telescope are the University of Arizona, Italy represented by the Osservatorio Astrofisico di Arcetri and the Research Corporation based in Tucson, Arizona. These three partners have committed sufficient funds to build the enclosure and the telescope populated with a single 8.4 meter optical train -- approximately 40 million dollars (1989). Based on this commitment, design and construction activities are now moving forward. Additional partners are being sought. The next mirror to be cast at the Steward Observatory Mirror Lab in the fall of 1996 will be the first borosilicate honeycomb primary for LBT. The baseline optical configuration of LBT includes wide field Cassegrain secondaries with optical foci above the primaries to provide a corrected one degree field at F/4. The infrared F/15 secondaries are a Gregorian design to allow maximum flexibility for adaptive optics. The F/15 secondaries are undersized to provide a low thermal background focal plane which is unvignetted over a 4 arcminute diameter field-of-view. The interferometric focus combining the light from the two 8.4 meter primaries will reimage two folded Gregorian focal planes to a central location. The telescope elevation structure accommodates swing arms which allow rapid interchange of the various secondary and tertiary mirrors. Maximum stiffness and minimal thermal disturbance continue to be important drivers for the detailed design of the telescope. The telescope structure accommodates installation of a vacuum bell jar for aluminizing the primary mirrors in-situ on the telescope. The detailed design of the telescope structure will be completed in 1996 by ADS Italia (Lecco) and European Industrial Engineering (Mestre). The final enclosure design is now in progress at M3 Engineering (Tucson), EIE and ADS Italia

  9. Unitals in Projective Planes

    CERN Document Server

    Barwick, Susan

    2008-01-01

    Unitals are key structures in projective planes, and have connections with other structures in algebra. This book presents a monograph on unitals embedded in finite projective planes. It offers a survey of the research literature on embedded unitals. It is suitable for graduate students and researchers who want to learn about this topic

  10. Focal epithelial hyperplasia: Case report.

    Science.gov (United States)

    Puriene, Alina; Rimkevicius, Arunas; Gaigalas, Mindaugas

    2011-01-01

    The purpose of the present article is to present a 15 year-old patient with focal epithelial hyperplasia and to review the references on the subject-related etiological, pathological, diagnostic and treatment aspects. Focal epithelial hyperplasia is a rare human papilloma virus (HPV) related to oral lesion with very low frequency within our population. Surgical treatment with a biopsy was performed, acanthosis and parakeratosis are consistent histopathological features, since the patient had no history of sexual contact and HIV infection, the virus was probably acquired from environmental sources.

  11. The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz detector array of bolometric polarimeters

    CERN Document Server

    Appel, John W; Amiri, Mandana; Araujo, Derek; Bennett, Charles L; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dunner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Hilton, Gene; Hinshaw, Gary F; Huang, Caroline; Irwin, Kent; Jones, Glenn; Karakla, John; Kogut, Alan J; Larson, David; Limon, Michele; Lowry, Lindsay; Marriage, Tobias; Mehrle, Nicholas; Miller, Amber D; Miller, Nathan; Moseleyb, Samuel H; Novakh, Giles; Reintsemad, Carl; Rostemab, Karwan; Stevensonb, Thomas; Towner, Deborah; U-Yen, Kongpop; Wagner, Emily; Watts, Duncan; Wollack, Edward; Xu, Zhilei; Zeng, Lingzhen

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) experiment aims to map the polarization of the Cosmic Microwave Background (CMB) at angular scales larger than a few degrees. Operating from Cerro Toco in the Atacama Desert of Chile, it will observe over 65% of the sky at 38, 93, 148, and 217 GHz. In this paper we discuss the design, construction, and characterization of the CLASS 38 GHz detector focal plane, the first ever Q-band bolometric polarimeter array.

  12. The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz Detector Array of Bolometric Polarimeters

    Science.gov (United States)

    Appel, John W.; Ali, Aamir; Amiri, Mandana; Araujo, Derek; Bennett, Charles L.; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T.; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dunner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Kogut, Alan J..; Miller, Nathan; Moseley, Samuel H.; Stevenson, Thomas; Towner, Deborah; U-Yen, Kongpop; Wollack, Edward

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) experiment aims to map the polarization of the Cosmic Microwave Background (CMB) at angular scales larger than a few degrees. Operating from Cerro Toco in the Atacama Desert of Chile, it will observe over 65% of the sky at 38, 93, 148, and 217 GHz. In this paper we discuss the design, construction, and characterization of the CLASS 38 GHz detector focal plane, the first ever Q-band bolometric polarimeter array.

  13. Focal Mechanism of Semi-Volcanic Deep Low-Frequency Earthquakes in Eastern Shimane

    Science.gov (United States)

    Aso, N.; Ohta, K.; Ide, S.

    2012-12-01

    Many deep low-frequency earthquakes (LFEs) occur near the island arc Mohorovicic discontinuities and far from both active volcanoes and plate boundaries. They are quite similar to volcanic LFEs beneath active volcanoes, which infers some fluid movement in the source region, and we regard them as "semi-volcanic" LFEs [Aso et al., 2011; 2012 (submitted)]. Several previous studies determined the focal mechanisms of volcanic and semi-volcanic LFEs using a small portion of information of the waveforms. Although the estimated focal mechanisms are various, they may not necessary support the variety of the actual physical process, owing to the large determination error [e.g., Nishidomi and Takeo, 1996; Ohmi and Obara, 2002; Nakamichi et al., 2003]. Here we determine the focal mechanisms by waveform inversion for LFEs in eastern Shimane in western Japan, where many LFEs occurred in a quiet region. The locations are also close to the fault plane of the 2000 western Tottori earthquake of Mw6.6, and right beneath Yokota volcano, which is a Quaternary volcanic cluster. We estimated the focal mechanisms of semi-volcanic LFEs in eastern Shimane by moment tensor inversion. The data are velocity seismograms at five stations of Hi-net near the epicenters. For each seismogram, we extracted a 1.5-second time window beginning from 0.2 seconds before the arrivals of either P-wave in a vertical component or S-wave in a horizontal component. The arrival time of each phase is picked manually first, and then corrected to minimize the variance between observed and synthetic waveforms. The local site amplification is estimated using far-field body waves from deep intraslab earthquakes, and collected for each seismogram. The synthetic waveforms were calculated using the discrete wavenumber integration method developed by Takeo [1985] for a horizontally layered structure. For 38 LFEs, which are equal to or larger than M1.2 (JMA magnitude) and recorded at all five stations, the focal mechanisms

  14. SPECT in Focal Epilepsies

    Directory of Open Access Journals (Sweden)

    Roderick Duncan

    2000-01-01

    Full Text Available Brain perfusion changes during seizures were first observed in the 1930s. Single Photon Emission Computed Tomography (SPECT was developed in the 1970s, and tracers suitable for the imaging of regional cerebral perfusion (rCP became available in the 1980s. The method was first used to study rCP in the interictal phase, and this showed areas of low perfusion in a proportion of cases, mainly in patients with temporal lobe epilepsies. However, the trapping paradigm of tracers such as hexamethyl propyleneamine oxime (HMPAO provided a practicable method of studying changes in rCP during seizures, and a literature was established in the late 1980s and early 1990s showing a typical sequence of changes during and after seizures of mesial temporal lobe origin; the ictal phase was associated with large increases in perfusion throughout the temporal lobe, with first the lateral, then the mesial temporal lobe becoming hypoperfused in the postictal phase. Activation and inhibition of other structures, such as the basal ganglia and frontal cortex, were also seen. Studies of seizures originating elsewhere in the brain have shown a variety of patterns of change, according to the structures involved. These changes have been used practically to aid the process of localisation of the epileptogenic zone so that epilepsy surgery can be planned.

  15. Focal fits during chlorambucil therapy

    Science.gov (United States)

    Naysmith, A.; Robson, R. H.

    1979-01-01

    An elderly man receiving chlorambucil for chronic lymphatic leukaemia developed focal fits. The onset and frequency were dose related. There was no evidence of metabolic disturbance or of meningeal leukaemia. Although reported in children and well recognized in animals, chlorambucil-induced fits in an adult have not been previously recorded. PMID:118440

  16. Focal lesions of the patella

    Energy Technology Data Exchange (ETDEWEB)

    Hedayati, B. [Royal national Orthopaedic Hospital Stanmore, Brockley Hill Stanmore, Department of Radiology, Middlesex (United Kingdom); Lewisham Hospital NHS Trust, Department of Radiology, London (United Kingdom); Saifuddin, A. [Royal national Orthopaedic Hospital Stanmore, Brockley Hill Stanmore, Department of Radiology, Middlesex (United Kingdom)

    2009-08-15

    Focal lesions of the patella may be identified during the investigation of anterior knee pain or as an incidental finding on radiological images. This pictorial review describes the radiographic appearances of a wide range of conditions that have been seen in this sesamoid bone. Where appropriate, computed tomography and magnetic resonance features have been included. (orig.)

  17. Linear Instability of the Plane Couette and Plane Poiseuille Flows

    CERN Document Server

    Chefranov, Sergey G

    2015-01-01

    We show possibility of the Plane Couette (PC) flow instability for Reynolds number Re>Reth=140. This new result of the linear hydrodynamic stability theory is obtained on the base of refusal from the traditionally used assumption on longitudinal periodicity of the disturbances along the direction of the fluid flow. We found that earlier existing understanding on the linear stability of this flow for any arbitrary large Reynolds number is directly related with an assumption on the separation of the variables of the spatial variability for the disturbance field and their periodicity in linear theory of stability. By the refusal from the pointed assumptions also for the Plane Poiseuille (PP) flow, we get a new threshold Reynolds value Reth=1040 that with 4% accuracy agrees with the experiment contrary to more than 500% discrepancy for the earlier known estimate Reth=5772 obtained in the frame of the linear theory but when using the "normal" disturbance form (S. A. Orszag, 1971).

  18. Fixed sagittal plane imbalance.

    Science.gov (United States)

    Savage, Jason W; Patel, Alpesh A

    2014-12-01

    Study Design Literature review. Objective To discuss the evaluation and management of fixed sagittal plane imbalance. Methods A comprehensive literature review was performed on the preoperative evaluation of patients with sagittal plane malalignment, as well as the surgical strategies to address sagittal plane deformity. Results Sagittal plane imbalance is often caused by de novo scoliosis or iatrogenic flat back deformity. Understanding the etiology and magnitude of sagittal malalignment is crucial in realignment planning. Objective parameters have been developed to guide surgeons in determining how much correction is needed to achieve favorable outcomes. Currently, the goals of surgery are to restore a sagittal vertical axis Sagittal plane malalignment is an increasingly recognized cause of pain and disability. Treatment of sagittal plane imbalance varies according to the etiology, location, and severity of the deformity. Fixed sagittal malalignment often requires complex reconstructive procedures that include osteotomy correction. Reestablishing harmonious spinopelvic alignment is associated with significant improvement in health-related quality-of-life outcome measures and patient satisfaction.

  19. Plane waves as tractor beams

    CERN Document Server

    Forgács, Péter; Romańczukiewicz, Tomasz

    2013-01-01

    It is shown that in a large class of systems plane waves can act as tractor beams: i.e., an incident plane wave can exert a pulling force on the scatterer. The underlying physical mechanism for the pulling force is due to the sufficiently strong scattering of the incoming wave into another mode having a larger wave number, in which case excess momentum is created behind the scatterer. Such a tractor beam or negative radiation pressure effect arises naturally in systems where the coupling between the scattering channels is due to Aharonov-Bohm (AB) gauge potentials. It is demonstrated that this effect is also present if the AB potential is an induced, ("artificial") gauge potential such as the one found in J. March-Russell, J. Preskill, F. Wilczek, Phys. Rev. Lett. 58 2567 (1992).

  20. Focal rigidity of flat tori

    Directory of Open Access Journals (Sweden)

    Ferry Kwakkel

    2011-12-01

    Full Text Available Given a closed Riemannian manifold (M, g, i.e. compact and boundaryless, there is a partition of its tangent bundle TM = ∪iΣi called the focal decomposition of TM. The sets Σi are closely associated to focusing of geodesics of (M, g, i.e. to the situation where there are exactly i geodesic arcs of the same length joining points p and q in M. In this note, we study the topological structure of the focal decomposition of a closed Riemannian manifold and its relation with the metric structure of the manifold. Our main result is that flat n-tori, n > 2, are focally rigid in the sense that if two flat tori are focally equivalent then the tori are isometric up to rescaling. The case n = 2 was considered before by F. Kwakkel.Dada uma variedade Riemanniana (M, g fechada, isto é, compacta e sem bordo, existe uma partição de seu fibrado tangente TM = ∪iΣi chamada decomposição focal de TM. Os conjuntos Σi estão intimamente associados ao modo como focalizam as geodésicas de (M,g, isto é, à situação em que existem exatamente i arcos de geodésica de mesmo comprimento unindo pontos p e q em M. Nesta nota, estudamos a estrutura topológica da decomposição focal de uma variedade Riemanniana fechada e sua relação com a estrutura métrica de M. Nosso principal resultado é que n-toros planos, n > 2, são focalmente rigidos, isto é, se dois toros planos são focalmente equivalentes, então os dois toros são isométricos módulo mudança de escala. O caso n = 2 foi considerado anteriormente por F. Kwakkel.

  1. Why do aftershocks occur? Relationship between mainshock rupture and aftershock sequence based on highly resolved hypocenter and focal mechanism distributions

    Science.gov (United States)

    Yukutake, Yohei; Iio, Yoshihisa

    2017-05-01

    In order to clarify the origin of aftershocks, we precisely analyze the hypocenters and focal mechanisms of the aftershocks following the 2000 Western Tottori Earthquake, which occurred in the western part of Japan, using data from dense seismic observations. We investigate whether aftershocks occur on the mainshock fault plane on which coseismic slip occurred or they represent the rupture of fractures surrounding the mainshock fault plane. Based on the hypocenter distribution of the aftershocks, the subsurface fault structure of the mainshock is estimated using principal component analysis. As a result, we can obtain the detail fault structure composed of 8 best-fit planes. We demonstrate that the aftershocks around the mainshock fault are distributed within zones of 1.0-1.5 km in thicknesses, and their focal mechanisms are significantly diverse. This result suggests that most of the aftershocks represent the rupture of fractures surrounding the mainshock fault rather than the rerupture of the mainshock fault. The aftershocks have a much wider zone compared with the exhumed fault zone in field observations, suggesting that many aftershocks occur outside the fault damage zone. We find that most aftershocks except in and around the large-slip region are well explained by coseismic stress changes. These results suggest that the thickness of the aftershock distribution may be controlled by the stress changes caused by the heterogeneous slip distribution during the mainshock. The aftershock is also distributed within a much wider zone than the hypocenter distribution observed in swarm activity in the geothermal region, which is thought to be caused by the migration of hydrothermal fluid. This result implies a difference in generation processes: Stress changes due to the mainshock contribute primarily to the occurrence of aftershocks, whereas earthquake swarms in the geothermal region are caused by fluid migration within the localized zone. [Figure not available: see

  2. Focal length estimation guided with object distribution on FocaLens dataset

    Science.gov (United States)

    Yan, Han; Zhang, Yu; Zhang, Shunli; Zhao, Sicong; Zhang, Li

    2017-05-01

    The focal length information of an image is indispensable for many computer vision tasks. In general, focal length can be obtained via camera calibration using specific planner patterns. However, for images taken by an unknown device, focal length can only be estimated based on the image itself. Currently, most of the single-image focal length estimation methods make use of predefined geometric cues (such as vanishing points or parallel lines) to infer focal length, which constrains their applications mainly on manmade scenes. The machine learning algorithms have demonstrated great performance in many computer vision tasks, but these methods are seldom used in the focal length estimation task, partially due to the shortage of labeled images for training the model. To bridge this gap, we first introduce a large-scale dataset FocaLens, which is especially designed for single-image focal length estimation. Taking advantage of the FocaLens dataset, we also propose a new focal length estimation model, which exploits the multiscale detection architecture to encode object distributions in images to assist focal length estimation. Additionally, an online focal transformation approach is proposed to further promote the model's generalization ability. Experimental results demonstrate that the proposed model trained on FocaLens can not only achieve state-of-the-art results on the scenes with distinct geometric cues but also obtain comparable results on the scenes even without distinct geometric cues.

  3. Focal cortical dysplasia – review

    Science.gov (United States)

    Kabat, Joanna; Król, Przemysław

    2012-01-01

    Summary Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults. Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed – from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized. Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe. Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes. New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life. Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias. The most common findings on MRI imaging include: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy. However, in type I cortical dysplasia, MR imaging is often normal, and also

  4. Fault Plane Orientations of Intermediate-Depth Earthquakes in South America

    Science.gov (United States)

    Warren, L. M.

    2013-12-01

    Extending from Colombia in the north to Chile and Argentina in the south, the South American subduction zone exhibits considerable variation: the subduction angle alternates between flat and steep; the subducting plate has complex structures such as ridges, plateaus, and fracture zones; and late Cenozoic volcanism in the overlying plate has gaps. I investigate the effect of these differences in incoming plate structure and subduction geometry on intermediate-depth earthquakes and use the results to test hypotheses for why intermediate-depth earthquakes occur. For all large (Mw ≥5.7) intermediate-depth earthquakes (60-360 km depth) in South America since 1990, I analyze rupture directivity to try to distinguish which of the two possible fault planes of the focal mechanism slipped in the earthquake. Of the 163 earthquakes that met the selection criteria, half were recorded with a sufficient distribution of stations to determine if there was directivity to the rupture and fault planes were identified for 31 events. Fault plane orientations are spatially coherent. In regions with "normal" subduction angles, such as the Central Volcanic Zone (southern Peru to central Chile), results are consistent with previous studies in Central America and the western Pacific subduction zones: most earthquakes rupture along subhorizontal faults and rupture azimuths are randomly distributed. In the Peruvian Flat Slab, identified fault planes dip eastward. After taking into account the angle of subduction, these faults are perpendicular to the faults that rupture in regions with normal subduction angles. Within sharply curved slab segments, such as the rebending of the plate at the eastern edge of the Peruvian flat slab, both orientations of faults slip. The observed flip in dominant fault plane orientation on either side of sharply curved slab segments suggests that bending and unbending stresses have an important role in controlling fault orientations. Pre-existing weak zones may

  5. Musical anhedonia after focal brain damage.

    Science.gov (United States)

    Belfi, Amy M; Evans, Erin; Heskje, Jonah; Bruss, Joel; Tranel, Daniel

    2017-03-01

    People listen to music because it is pleasurable. However, there are individual differences in the reward value of music. At the extreme low end of this continuum, individuals who derive no pleasure from music are said to have 'musical anhedonia.' Cases of acquired musical anhedonia following focal brain damage are rare, with only a handful having been reported in the scientific literature. Here, we surveyed a large sample of patients with focal brain damage to identify the frequency, specificity, and neural correlates of acquired musical anhedonia. Participants completed the Musical anhedonia Questionnaire and the Barcelona Music Reward Questionnaire (Mas-Herrero et al., 2013) to assess changes in musical enjoyment and reward following brain injury. Neuroanatomical data were analyzed with a proportional MAP-3 method to create voxelwise lesion proportion difference maps. No clear or consistent neuroanatomical correlates of musical anhedonia were identified. One patient with damage to the right-hemisphere putamen and internal capsule displayed specific and severe acquired musical anhedonia. These findings indicate that acquired musical anhedonia is very uncommon, a result which is consistent with the fact that only a small number of such cases have been reported in the literature. This rarity could have positive implications for the therapeutic potentialities of music in patients with severe neurological disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Inhibition of focal adhesion kinase (FAK) signaling in focal adhesions decreases cell motility and proliferation.

    OpenAIRE

    1996-01-01

    It has been proposed that the focal adhesion kinase (FAK) mediates focal adhesion formation through tyrosine phosphorylation during cell adhesion. We investigated the role of FAK in focal adhesion structure and function. Loading cells with a glutathione-S-transferase fusion protein (GST-Cterm) containing the FAK focal adhesion targeting sequence, but not the kinase domain, decreased the association of endogenous FAK with focal adhesions. This displacement of endogenous FAK in both BALB/c 3T3 ...

  7. Implementation of focal zooming on the Nike KrF laser

    Science.gov (United States)

    Kehne, D. M.; Karasik, M.; Aglitsky, Y.; Smyth, Z.; Terrell, S.; Weaver, J. L.; Chan, Y.; Lehmberg, R. H.; Obenschain, S. P.

    2013-01-01

    In direct drive inertial confinement laser fusion, a pellet containing D-T fuel is imploded by ablation arising from absorption of laser energy at its outer surface. For optimal coupling, the focal spot of the laser would continuously decrease to match the reduction in the pellet's diameter, thereby minimizing wasted energy. A krypton-fluoride laser (λ = 248 nm) that incorporates beam smoothing by induced spatial incoherence has the ability to produce a high quality focal profile whose diameter varies with time, a property known as focal zooming. A two-stage focal zoom has been demonstrated on the Nike laser at the Naval Research Laboratory. In the experiment, a 4.4 ns laser pulse was created in which the on-target focal spot diameter was 1.3 mm (full width at half maximum) for the first 2.4 ns and 0.28 mm for the final 2 ns. These two diameters appear in time-integrated focal plane equivalent images taken at several locations in the amplification chain. Eight of the zoomed output beams were overlapped on a 60 μm thick planar polystyrene target. Time resolved images of self-emission from the rear of the target show the separate shocks launched by the two corresponding laser focal diameters.

  8. Implementation of focal zooming on the Nike KrF laser

    Energy Technology Data Exchange (ETDEWEB)

    Kehne, D. M.; Karasik, M.; Weaver, J. L.; Chan, Y.; Obenschain, S. P. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Aglitsky, Y. [Science Applications International, McLean, Virginia 22150 (United States); Smyth, Z.; Lehmberg, R. H. [Research Support Instruments, Inc., Lanham, Maryland 20706 (United States); Terrell, S. [Commonwealth Technologies, Inc., Alexandria, Virginia 22315 (United States)

    2013-01-15

    In direct drive inertial confinement laser fusion, a pellet containing D-T fuel is imploded by ablation arising from absorption of laser energy at its outer surface. For optimal coupling, the focal spot of the laser would continuously decrease to match the reduction in the pellet's diameter, thereby minimizing wasted energy. A krypton-fluoride laser ({lambda}= 248 nm) that incorporates beam smoothing by induced spatial incoherence has the ability to produce a high quality focal profile whose diameter varies with time, a property known as focal zooming. A two-stage focal zoom has been demonstrated on the Nike laser at the Naval Research Laboratory. In the experiment, a 4.4 ns laser pulse was created in which the on-target focal spot diameter was 1.3 mm (full width at half maximum) for the first 2.4 ns and 0.28 mm for the final 2 ns. These two diameters appear in time-integrated focal plane equivalent images taken at several locations in the amplification chain. Eight of the zoomed output beams were overlapped on a 60 {mu}m thick planar polystyrene target. Time resolved images of self-emission from the rear of the target show the separate shocks launched by the two corresponding laser focal diameters.

  9. In plane oscillation of a bifilar pendulum

    Science.gov (United States)

    Hinrichsen, Peter F.

    2016-11-01

    The line tensions, the horizontal and vertical accelerations as well as the period of large angle oscillations parallel to the plane of a bifilar suspension are presented and have been experimentally investigated using strain gauges and a smart phone. This system has a number of advantages over the simple pendulum for studying large angle oscillations, and for measuring the acceleration due to gravity.

  10. Interferon Induced Focal Segmental Glomerulosclerosis

    Science.gov (United States)

    Bayram Kayar, Nuket; Alpay, Nadir; Hamdard, Jamshid; Emegil, Sebnem; Bag Soydas, Rabia; Baysal, Birol

    2016-01-01

    Behçet's disease is an inflammatory disease of unknown etiology which involves recurring oral and genital aphthous ulcers and ocular lesions as well as articular, vascular, and nervous system involvement. Focal segmental glomerulosclerosis (FSGS) is usually seen in viral infections, immune deficiency syndrome, sickle cell anemia, and hyperfiltration and secondary to interferon therapy. Here, we present a case of FSGS identified with kidney biopsy in a patient who had been diagnosed with Behçet's disease and received interferon-alpha treatment for uveitis and presented with acute renal failure and nephrotic syndrome associated with interferon. PMID:27847659

  11. Focal epithelial hyperplasia: Heck disease.

    Science.gov (United States)

    Cohen, P R; Hebert, A A; Adler-Storthz, K

    1993-09-01

    Two sisters of Mexican ancestry had focal epithelial hyperplasia (FEH). The lesions on the oral mucosa of the older child were initially misinterpreted as representing sexual abuse. Microscopic evaluation of a hematoxylin and eosin-stained section from a lower lip papule demonstrated the histologic features of FEH. Although human papillomavirus (HPV) type 13 and HPV32 have been most consistently present in FEH lesions, types 6, 11, 13, and 32 were not detected in the paraffin-embedded tissue specimen of our patient using an in situ hybridization technique. The lesions persisted or recurred during management using destructive modalities; subsequently, they completely resolved spontaneously.

  12. Focal epithelial hyperplasia (Heck's disease

    Directory of Open Access Journals (Sweden)

    Parichehr Gheliani

    2011-11-01

    Full Text Available Focal epithelial hyperplasia (Heck is a rare lesion caused by human papilloma virus subtype 13 or 32 and presents as multiple small white or pink papules on the mucosal surface of lips, buccal mucosa and tongue usually seen in children and adolescent of American Indian and Eskimo background. This disease has a genetic basis. The site of new lesions and recurrence are unpredictable. Continued follow up of the patient is often necessary. In this report, a 50-year-old woman is described with benign papillomatous lesions on dorsal surface of tongue for 15 years

  13. Eight plane IPND mechanical testing.

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, A.; Guarino, V.; Wood, K.; Nephew, T.; Ayres, D.; Lee, A.; High Energy Physics; FNAL

    2008-03-18

    A mechanical test of an 8 plane IPND mechanical prototype, which was constructed using extrusions from the testing/tryout of the 16 cell prototype extrusion die in Argonne National Laboratory, was conducted. There were 4 vertical and 4 horizontal planes in this 8 plane IPND prototype. Each vertical plane had four 16 cell extrusions, while each horizontal plane had six 16 cell extrusions. Each plane was glued together using the formulation of Devcon adhesive, Devcon 60. The vertical extrusions used in the vertical planes shares the same dimensions as the horizontal extrusions in the horizontal planes with the average web thickness of 2.1 mm and the average wall thickness of 3.1 mm. This mechanical prototype was constructed with end-seals on the both ends of the vertical extrusions. The gaps were filled with epoxy between extrusions and end-seals. The overall dimension of IPND is 154.8 by 103.1 by 21.7 inches with the weight of approximately 1200 kg, as shown in a figure. Two similar mechanical tests of 3 layer and 11 layer prototypes have been done in order to evaluate the strength of the adhesive joint between extrusions in the NOvA detector. The test showed that the IPND prototype was able to sustain under the loading of weight of itself and scintillator. Two FEA models were built to verify the measurement data from the test. The prediction from FEA slice model seems correlated reasonably well to the test result, even under a 'rough' estimated condition for the wall thickness (from an untuned die) and an unknown property of 'garage type' extrusion. A full size of FEA 3-D model also agrees very well with the test data from strain gage readings. It is worthy to point out that the stress distribution of the structure is predominantly determined by the internal pressure, while the buckling stability relies more on the loading weight from the extrusions themselves and scintillate. Results of conducted internal pressure tests, including 3- cell, 11

  14. Butterfly Wings Are Three-Dimensional: Pupal Cuticle Focal Spots and Their Associated Structures in Junonia Butterflies.

    Science.gov (United States)

    Taira, Wataru; Otaki, Joji M

    2016-01-01

    Butterfly wing color patterns often contain eyespots, which are developmentally determined at the late larval and early pupal stages by organizing activities of focal cells that can later form eyespot foci. In the pupal stage, the focal position of a future eyespot is often marked by a focal spot, one of the pupal cuticle spots, on the pupal surface. Here, we examined the possible relationships of the pupal focal spots with the underneath pupal wing tissues and with the adult wing eyespots using Junonia butterflies. Large pupal focal spots were found in two species with large adult eyespots, J. orithya and J. almana, whereas only small pupal focal spots were found in a species with small adult eyespots, J. hedonia. The size of five pupal focal spots on a single wing was correlated with the size of the corresponding adult eyespots in J. orithya. A pupal focal spot was a three-dimensional bulge of cuticle surface, and the underside of the major pupal focal spot exhibited a hollowed cuticle in a pupal case. Cross sections of a pupal wing revealed that the cuticle layer shows a curvature at a focal spot, and a positional correlation was observed between the cuticle layer thickness and its corresponding cell layer thickness. Adult major eyespots of J. orithya and J. almana exhibited surface elevations and depressions that approximately correspond to the coloration within an eyespot. Our results suggest that a pupal focal spot is produced by the organizing activity of focal cells underneath the focal spot. Probably because the focal cell layer immediately underneath a focal spot is thicker than that of its surrounding areas, eyespots of adult butterfly wings are three-dimensionally constructed. The color-height relationship in adult eyespots might have an implication in the developmental signaling for determining the eyespot color patterns.

  15. Butterfly Wings Are Three-Dimensional: Pupal Cuticle Focal Spots and Their Associated Structures in Junonia Butterflies.

    Directory of Open Access Journals (Sweden)

    Wataru Taira

    Full Text Available Butterfly wing color patterns often contain eyespots, which are developmentally determined at the late larval and early pupal stages by organizing activities of focal cells that can later form eyespot foci. In the pupal stage, the focal position of a future eyespot is often marked by a focal spot, one of the pupal cuticle spots, on the pupal surface. Here, we examined the possible relationships of the pupal focal spots with the underneath pupal wing tissues and with the adult wing eyespots using Junonia butterflies. Large pupal focal spots were found in two species with large adult eyespots, J. orithya and J. almana, whereas only small pupal focal spots were found in a species with small adult eyespots, J. hedonia. The size of five pupal focal spots on a single wing was correlated with the size of the corresponding adult eyespots in J. orithya. A pupal focal spot was a three-dimensional bulge of cuticle surface, and the underside of the major pupal focal spot exhibited a hollowed cuticle in a pupal case. Cross sections of a pupal wing revealed that the cuticle layer shows a curvature at a focal spot, and a positional correlation was observed between the cuticle layer thickness and its corresponding cell layer thickness. Adult major eyespots of J. orithya and J. almana exhibited surface elevations and depressions that approximately correspond to the coloration within an eyespot. Our results suggest that a pupal focal spot is produced by the organizing activity of focal cells underneath the focal spot. Probably because the focal cell layer immediately underneath a focal spot is thicker than that of its surrounding areas, eyespots of adult butterfly wings are three-dimensionally constructed. The color-height relationship in adult eyespots might have an implication in the developmental signaling for determining the eyespot color patterns.

  16. Idiopathic focal epilepsies: the "lost tribe".

    Science.gov (United States)

    Pal, Deb K; Ferrie, Colin; Addis, Laura; Akiyama, Tomoyuki; Capovilla, Giuseppe; Caraballo, Roberto; de Saint-Martin, Anne; Fejerman, Natalio; Guerrini, Renzo; Hamandi, Khalid; Helbig, Ingo; Ioannides, Andreas A; Kobayashi, Katsuhiro; Lal, Dennis; Lesca, Gaetan; Muhle, Hiltrud; Neubauer, Bernd A; Pisano, Tiziana; Rudolf, Gabrielle; Seegmuller, Caroline; Shibata, Takashi; Smith, Anna; Striano, Pasquale; Strug, Lisa J; Szepetowski, Pierre; Valeta, Thalia; Yoshinaga, Harumi; Koutroumanidis, Michalis

    2016-09-01

    term "benign" is often used in connection with the IFEs and is increasingly being challenged. Certainly most of these disorders are not associated with the devastating cognitive and behavioural problems seen with early childhood epileptic encephalopathies, such as West or Dravet syndromes. However, it is clear that specific, and sometimes persistent, neuropsychological deficits in attention, language and literacy accompany many of the IFEs that, when multiplied by the large numbers affected, make up a significant public health problem. Understanding the nature, distribution, evolution, risk and management of these is an important area of current research. A corollary to such questions regarding comorbidities is the role of focal interictal spikes and their enduring impact on cognitive functioning. What explains the paradox that epilepsies characterised by abundant interictal epileptiform abnormalities are often associated with very few clinical seizures? This is an exciting area in both clinical and experimental arenas and will eventually have important implications for clinical management of the whole child, taking into account not just seizures, but also adaptive functioning and quality of life. For several decades, we have accepted an evidence-free approach to using or not using antiepileptic drugs in IFEs. There is huge international variation and only a handful of studies examining neurocognitive outcomes. Clearly, this is a situation ready for an overhaul in practice. Fundamental to understanding treatment is knowledge of aetiology. In recent years, there have been several significant discoveries in IFEs from studies of copy number variation, exome sequencing, and linkage that prompt reconsideration of the "unknown cause" classification and strongly suggest a genetic aetiology. The IFE are strongly age-related, both with regards to age of seizure onset and remission. Does this time window solely relate to a similar age-related gene expression, or are there

  17. Lines, Circles, Planes and Spheres

    CERN Document Server

    Purdy, George B

    2009-01-01

    Let $S$ be a set of $n$ points in $\\mathbb{R}^3$, no three collinear and not all coplanar. If at most $n-k$ are coplanar and $n$ is sufficiently large, the total number of planes determined is at least $1 + k \\binom{n-k}{2}-\\binom{k}{2}(\\frac{n-k}{2})$. For similar conditions and sufficiently large $n$, (inspired by the work of P. D. T. A. Elliott in \\cite{Ell67}) we also show that the number of spheres determined by $n$ points is at least $1+\\binom{n-1}{3}-t_3^{orchard}(n-1)$, and this bound is best possible under its hypothesis. (By $t_3^{orchard}(n)$, we are denoting the maximum number of three-point lines attainable by a configuration of $n$ points, no four collinear, in the plane, i.e., the classic Orchard Problem.) New lower bounds are also given for both lines and circles.

  18. Pathogenesis of Focal Segmental Glomerulosclerosis

    Directory of Open Access Journals (Sweden)

    Beom Jin Lim

    2016-11-01

    Full Text Available Focal segmental glomerulosclerosis (FSGS is characterized by focal and segmental obliteration of glomerular capillary tufts with increased matrix. FSGS is classified as collapsing, tip, cellular, perihilar and not otherwise specified variants according to the location and character of the sclerotic lesion. Primary or idiopathic FSGS is considered to be related to podocyte injury, and the pathogenesis of podocyte injury has been actively investigated. Several circulating factors affecting podocyte permeability barrier have been proposed, but not proven to cause FSGS. FSGS may also be caused by genetic alterations. These genes are mainly those regulating slit diaphragm structure, actin cytoskeleton of podocytes, and foot process structure. The mode of inheritance and age of onset are different according to the gene involved. Recently, the role of parietal epithelial cells (PECs has been highlighted. Podocytes and PECs have common mesenchymal progenitors, therefore, PECs could be a source of podocyte repopulation after podocyte injury. Activated PECs migrate along adhesion to the glomerular tuft and may also contribute to the progression of sclerosis. Markers of activated PECs, including CD44, could be used to distinguish FSGS from minimal change disease. The pathogenesis of FSGS is very complex; however, understanding basic mechanisms of podocyte injury is important not only for basic research, but also for daily diagnostic pathology practice.

  19. Influence of focal spot on characteristics of very small diameter radiosurgical beams.

    Science.gov (United States)

    Sham, Edwin; Seuntjens, Jan; Devic, Slobodan; Podgorsak, Ervin B

    2008-07-01

    Percentage depth dose (PDD) distributions and beam profiles of very small diameter (1.5-5 mm) megavoltage radiosurgical beams calculated with Monte Carlo (MC) technique critically depend on the diameter of the circular focal spot used in the simulation: The smaller is the field diameter, the larger is the effect. Thus, in simulations of radiosurgical fields that have diameters of the order of the focal spot size, an accurate focal spot geometry should be used. We used a simplified moving slit technique in conjunction with a diode detector for evaluation of the focal spot size and shape of a megavoltage 6 MV linac as well as for determination of the equivalent focal spot diameter of the linac for use in MC simulations. The measured total diode signal contains three components: A direct focal spot signal, a background signal, and an extra-focal radiation signal. A single profile scan of the focal spot signal is Gaussian like in shape, and its full width at half maximum is used to define the focal spot dimension for this scan. The focal spot of our 6 MV linac is approximated with a Gaussian circle, and when the geometry of the effective focal spot circle is used in MC simulations, the agreement between MC-calculated and measured PDD distributions as well as beam profiles is good even for radiosurgical fields as small as 1.5 mm in diameter. Our results also confirm that matching the penumbral areas of accurately measured large-field beam profiles to the same areas of the MC-calculated beam profiles reliably leads to a realistic effective focal spot size for use in MC simulations of very small diameter beams.

  20. Anomalously large gap anisotropy in the [ital a]-[ital b] plane of Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[delta

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Z.; Dessau, D.S.; Wells, B.O.; King, D.M.; Spicer, W.E.; Arko, A.J.; Marshall, D.; Lombardo, L.W.; Kapitulnik, A.; Dickinson, P.; Doniach, S.; DiCarlo, J.; Loeser, T.; Park, C.H. (Department of Applied Physics, Stanford University, Stanford, California 94305 (United States) Solid State Electronics Laboratory and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305-4055 (United States) Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States))

    1993-03-08

    Superconducting gap anisotropy at least an order of magnitude larger than that of the conventional superconductors has been observed in the [ital a]-[ital b] plane of Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[delta

  1. Boundaries in digital planes

    Directory of Open Access Journals (Sweden)

    Efim Khalimsky

    1990-01-01

    Full Text Available The importance of topological connectedness properties in processing digital pictures is well known. A natural way to begin a theory for this is to give a definition of connectedness for subsets of a digital plane which allows one to prove a Jordan curve theorem. The generally accepted approach to this has been a non-topological Jordan curve theorem which requires two different definitions, 4-connectedness, and 8-connectedness, one for the curve and the other for its complement.

  2. BKP plane partitions

    Energy Technology Data Exchange (ETDEWEB)

    Foda, Omar; Wheeler, Michael [Department of Mathematics and Statistics, University of Melbourne, Parkville, Victoria 3010 (Australia)

    2007-01-15

    Using BKP neutral fermions, we derive a product expression for the generating function of volume-weighted plane partitions that satisfy two conditions. If we call a set of adjacent equal height-h columns, h > 0, an h-path, then 1. Every h-path can assume one of two possible colours. 2. There is a unique way to move along an h-path from any column to another.

  3. Periodontitis in patients with focal tuberculosis

    Directory of Open Access Journals (Sweden)

    Alexandrova Е.А.

    2010-12-01

    Full Text Available The research goal is to investigate the mechanisms of formation and peculiarities of periodontitis in patients with focal tuberculosis. Patients with periodontitis and focal tuberculosis are proved to develop local inflammatory reaction with increased infection and activation of proinflammatory cytokines in parodontal pockets fluid. The main risk factor of frequent and durable recurrence of parodontal pathology in case of focal tuberculosis was the development of pathologic process as a cause of disbalance of lipid peroxidation and antioxidant system, endotoxicosis syndrome

  4. Focal properties of geodesic waveguide lenses

    Science.gov (United States)

    Verber, C. M.; Vahey, D. W.; Wood, V. E.

    1976-01-01

    The focal properties of uncorrected geodesic lenses in ion-exchanged glass waveguides are reported. A 13.8-mm-focal-length lens resolved beams with an angular separation of 27.6 mrad, while a 28-mm-focal-length lens resolved beams with an angular separation of only 3.3 mrad. Intensity profiles of the focal region of the former lens revealed a 40-micron spot size when the input aperture was 5 mm, and a spot size of 7.7 microns when the aperture was reduced to 1 mm. This value is close to the diffraction-limited spot size of 5.7 microns.

  5. The Large Binocular Telescope Project

    Science.gov (United States)

    Hill, J. M.

    1995-05-01

    The Large Binocular Telescope (LBT) Project has evolved from concepts first proposed in 1985. The present partners involved in the design and construction of this 2 x 8.4 meter binocular telescope are the University of Arizona, Italy represented by the Osservatorio Astrofisico di Arcetri and the Research Corporation based in Tucson. These three partners have committed sufficient funds to build the enclosure and the telescope populated with a single 8.4 meter optical train --- approximately 40 million dollars (1989). Based on this commitment, design and construction activities are now moving forward. Additional partners are being sought. The next mirror to be cast at the Steward Observatory Mirror Lab in spring of 1996 will be the first borosilicate honeycomb primary for LBT. The baseline optical configuration of LBT includes wide field Cassegrain secondaries with optical foci above the primaries to provide a corrected one degree field at F/4. The infrared F/15 secondaries are a Gregorian design to allow maximicrons flexibility for adaptive optics. The F/15 secondaries are undersized to provide a low thermal background focal plane which is unvignetted over a 4 arcminute diameter field-of-view. The interferometric focus combining the light from the two 8.4 meter primaries will reimage two folded Gregorian focal planes to a central location. The telescope elevation structure accommodates swing arms which allow rapid interchange of the various secondary and tertiary mirrors. Maximicrons stiffness and minimal thermal disturbance continue to be important drivers for the detailed design of the telescope. The telescope structure accommodates installation of a vacuum bell jar for aluminizing the primary mirrors in-situ on the telescope. The detailed design of the telescope structure will be completed in 1995 by ADS Italia (Lecco) and European Industrial Engineering (Mestre). The final enclosure design is now in progress at M3 Engineering (Tucson) and ADS Italia

  6. Focal epithelial hyperplasia - an update.

    Science.gov (United States)

    Said, Ahmed K; Leao, Jair C; Fedele, Stefano; Porter, Stephen R

    2013-07-01

    Focal epithelial hyperplasia (FEH) is an asymptomatic benign mucosal disease, which is mostly observed in specific groups in certain geographical regions. FEH is usually a disease of childhood and adolescence and is generally associated with people who live in poverty and of low socioeconomic status. Clinically, FEH is typically characterized by multiple, painless, soft, sessile papules, plaques or nodules, which may coalesce to give rise to larger lesions. Human papillomavirus (HPV), especially genotypes 13 and 32, have been associated and detected in the majority of FEH lesions. The clinical examination and social history often allow diagnosis, but histopathological examination of lesional tissue is usually required to confirm the exact diagnosis. FEH sometimes resolves spontaneously however, treatment is often indicated as a consequence of aesthetic effects or any interference with occlusion. There remains no specific therapy for FEH, although surgical removal, laser excision or possibly topical antiviral agents may be of benefit. There remains no evidence that FEH is potentially malignant.

  7. An Introduction to the E-ELT Instrumentation and Post-focal Adaptive Optics Module Studies

    Science.gov (United States)

    D'Odorico, S.; Ramsay, S.; Hubin, N.; Gonzalez, J. C.; Zerbi, F. M.

    2010-06-01

    The following eleven articles provide short summaries of the conceptual design studies for the European Extremely Large Telescope instruments and post-focal adaptive optics modules. The background and scope of these studies is outlined in this introduction.

  8. Focal fatty infiltra- tion and focal fatty sparing of the liver

    African Journals Online (AJOL)

    Enrique

    Focal fatty infiltration of the liver is caused by focal ... has also been described in children.1. The most common cause is alcohol abuse, although diabetes, obesity, cer- tain drugs, toxins ... infiltration was not initially consid- ered are reported.

  9. Earthquake focal mechanisms and stress orientations in the eastern Swiss Alps

    Energy Technology Data Exchange (ETDEWEB)

    Marschall, I.; Deichmann, N. [Swiss Seismological Service, ETH Zuerich, Zuerich (Switzerland); Marone, F. [Paul Scherrer Institute PSI, Villigen (Switzerland)

    2013-04-15

    This study presents an updated set of earthquake focal mechanisms in the Helvetic and Penninic/Austroalpine domains of the eastern Swiss Alps. In eight cases, based on high-precision relative hypocentre locations of events within individual earthquake sequences, it was possible to identify the active fault plane. Whereas the focal mechanisms in the Helvetic domain are mostly strike-slip, the Penninic/Austroalpine domain is dominated by normal-faulting mechanisms. Given this systematic difference in faulting style, an inversion for the stress field was performed separately for the two regions. The stress field in the Penninic/Austroalpine domain is characterized by extension oriented obliquely to the E-W strike of the orogen. Hence, the Penninic nappes, which were emplaced as large-scale compressional structures during the Alpine orogenesis, are now deforming in an extensional mode. This contrasts with the more compressional strike-slip regime in the Helvetic domain towards the northern Alpine front. Relative to the regional stress field seen in the northern Alpine foreland with a NNW-SSE compression and an ENE-WSW extension, the orientation of the least compressive stress in the Penninic/Austroalpine domain is rotated counter-clockwise by about 40 °C. Following earlier studies, the observed rotation of the orientation of the least compressive stress in the Penninic/Austroalpine region can be explained as the superposition of the regional stress field of the northern foreland and a uniaxial extensional stress perpendicular to the local trend of the Alpine mountain belt. (authors)

  10. Image plane sweep volume illumination.

    Science.gov (United States)

    Sundén, Erik; Ynnerman, Anders; Ropinski, Timo

    2011-12-01

    In recent years, many volumetric illumination models have been proposed, which have the potential to simulate advanced lighting effects and thus support improved image comprehension. Although volume ray-casting is widely accepted as the volume rendering technique which achieves the highest image quality, so far no volumetric illumination algorithm has been designed to be directly incorporated into the ray-casting process. In this paper we propose image plane sweep volume illumination (IPSVI), which allows the integration of advanced illumination effects into a GPU-based volume ray-caster by exploiting the plane sweep paradigm. Thus, we are able to reduce the problem complexity and achieve interactive frame rates, while supporting scattering as well as shadowing. Since all illumination computations are performed directly within a single rendering pass, IPSVI does not require any preprocessing nor does it need to store intermediate results within an illumination volume. It therefore has a significantly lower memory footprint than other techniques. This makes IPSVI directly applicable to large data sets. Furthermore, the integration into a GPU-based ray-caster allows for high image quality as well as improved rendering performance by exploiting early ray termination. This paper discusses the theory behind IPSVI, describes its implementation, demonstrates its visual results and provides performance measurements.

  11. The INTEGRAL Galactic Plane Scanning

    CERN Document Server

    Fiocchi, Mariateresa

    2013-01-01

    After the first nine years of INTEGRAL operational life, the discovery of new sources and source types, a large fraction of which are highly transient or highly absorbed, is certainly one of the most compelling results and legacies of INTEGRAL. Frequent monitoring of the Galactic Plane in AO8 and AO9 campaigns allowed us to detect transient sources, both known and new, confirming that the gamma-ray sky is dominated by the extreme variability of different classes of objects. Regular scans of the Galactic Plane by INTEGRAL provide the most sensitive hard X-ray wide survey to date of our Galaxy, with flux limits of the order of 0.3 mCrab for an exposure time of ~2Ms. Many transient sources have been detected on a wide range of time scales (~hours to months) and identified by triggered followup observations, mainly by Swift/XRT and optical/infrared telescopes. These discoveries are very important to characterize the X-ray binary population in our Galaxy, that is necessary input for evolution studies. The transien...

  12. The HAWC Galactic Plane Survey

    Science.gov (United States)

    Hui, Michelle

    2016-03-01

    The High Altitude Water Cherenkov (HAWC) Observatory is an all-sky surveying instrument that covers 2/3 of the sky in 24 hours. It is designed with an emphasis on continuous sky coverage for transient events, and on the measurement of extended and large-scale structures. The array is located in Sierra Negra, Mexico at an elevation of 4,100 m and was inaugurated in March 2015. The HAWC array consists of 300 water Cherenkov detectors and is sensitive to extensive air showers triggered by cosmic rays and gamma rays from 100 GeV to >100 TeV. Thanks to its modular design, data taking began in Summer 2013 with 1/3 of the array. Analysis of the first year of data with the partial array shows detections that are coincident with known TeV supernova remnants and pulsar wind nebulae along the Galactic plane. Spectral and morphological analyses are ongoing to study the particle population and acceleration mechanism of these objects. With a growing data set taken with the completed array, source searches are underway for both point-like and extended emission along the Galactic plane, which contain many objects such as pulsar wind nebulae, young star clusters, and binaries.

  13. Plane and geodetic surveying

    CERN Document Server

    Johnson, Aylmer

    2004-01-01

    Plane and Geodetic Surveying blends theory and practice, conventional techniques and GPS, to provide the ideal book for students of surveying.Detailed guidance is given on how and when the principle surveying instruments (theodolites, Total Stations, levels and GPS) should be used. Concepts and formulae needed to convert instrument readings into useful results are explained. Rigorous explanations of the theoretical aspects of surveying are given, while at the same time a wealth of useful advice about conducting a survey in practice is provided. An accompanying least squares adjustment program

  14. An adaptive joint focal-mechanism inversion method for microseismic data: Application to Aneth CO2 Enhanced Oil Recovery Field

    Science.gov (United States)

    Chen, Y.; Chen, T.; Huang, L.

    2016-12-01

    A good azimuthal coverage of geophones is essentially important for focal-mechanism inversion of passive seismic data. However, microseismic monitoring for CO2 injection-induced seisimicity using borehole geophones often suffers from a poor azimuthal coverage of geophones, leading to large uncertainties in inversion. The focal mechanisms of microseismic events occurred within a small region are often similar to one another. We develop an adaptive focal-mechanism inversion method to invert microseismic events with similar focal mechanisms. We first classify microseismic events with similar focal mechanisms into clusters, and then invert the events in a cluster with the same focal mechanism simultaneously. Such inversion strategy is capable of improving convergent rate and reducing inversion uncertainty with abundant data from different azimuths. We develop a new double-difference focal-mechanism inversion method to further improve focal-mechanism inversion by minimizing the residual between observed and synthetic waveforms for pairs of microseismic events at adjacent locations. Our new algorithm allows us to constrain the focal mechanisms among events adjacent to one another. We apply our new adaptive joint focal-mechanism inversion method to microseismic data acquired using a borehole geophone string at a CO2 enhanced oil recovery field in Aneth, Utah. We compare our inversion results with those obtained from inverting focal mechanism for each microseismic event independently, demonstrating that our new inversion method greatly reduce the inversion uncertainty caused by the limited azimuthal coverage of borehole geophones.

  15. Thermally induced changes in the focal distance of composite mirrors - Composites with a zero coefficient of thermal expansion of the radius of curvature

    Science.gov (United States)

    Dolgin, Benjamin P.

    1992-01-01

    Calculations are presented of the coefficient of thermal expansion (CTE) of the radius of curvature of the reflector face sheets made of a quasi-isotropic composite. It is shown that, upon cooling, the change of the CTE of the focal distance of the mirror is equal to that of the radius of the curvature of the reflector face sheet. The CTE of the radius of the curvature of a quasi-isotropic composite face sheet depends on both the in-plane and the out-of-plane CTEs. The zero in-plane CTE of a face sheet does not guarantee mirrors with no focal length changes.

  16. Focality, stochasticity and neuroanatomic propagation in ALS pathogenesis.

    Science.gov (United States)

    Ravits, John

    2014-12-01

    Amyotrophic lateral sclerosis (ALS) phenotypes such as limb ALS, bulbar ALS, primary lateral sclerosis and primary muscular atrophy are highly heterogeneous and exist on a continuum. These are largely determined by the neuroanatomy of the underlying pathological changes, which can be clinically imputed. Deconstructing these early in disease, before temporal-spatial summation induces complexity, shows that ALS begins focally at a seemingly random location and progresses contiguously. This suggests that focality and anatomic propagation of pathology are significant parts of pathogenesis-disease propagates over space as well as progresses over time. Focality and neuroanatomic propagation can explain how dominant genetic traits manifest with heterogeneous phenotypes, since the anatomic site of outbreak is a prime determinant of phenotype. Focality and neuroanatomic propagation can also explain why frontotemporal dementia (FTD), a neurodegeneration closely related to ALS, has heterogeneous phenotypes, since here too the anatomic site of the outbreak is a prime determinant of phenotype. There are two distinct types of neuroanatomic propagation: contiguous propagation, which occurs side-to-side regionally through the extracellular matrix independent of synaptic connection; and network propagation, which occurs end-to-end dependent on synaptic connections and axonal transmission in connected neuronal networks. The molecular basis of neuroanatomic propagation is unknown, although prion-like misfolding and templating of pathogenic proteins is a compelling unifying hypothesis.

  17. The Aerodynamic Plane Table

    Science.gov (United States)

    Zahm, A F

    1924-01-01

    This report gives the description and the use of a specially designed aerodynamic plane table. For the accurate and expeditious geometrical measurement of models in an aerodynamic laboratory, and for miscellaneous truing operations, there is frequent need for a specially equipped plan table. For example, one may have to measure truly to 0.001 inch the offsets of an airfoil at many parts of its surface. Or the offsets of a strut, airship hull, or other carefully formed figure may require exact calipering. Again, a complete airplane model may have to be adjusted for correct incidence at all parts of its surfaces or verified in those parts for conformance to specifications. Such work, if but occasional, may be done on a planing or milling machine; but if frequent, justifies the provision of a special table. For this reason it was found desirable in 1918 to make the table described in this report and to equip it with such gauges and measures as the work should require.

  18. Pathogenetic mechanisms of focal cortical dysplasia.

    Science.gov (United States)

    Marin-Valencia, Isaac; Guerrini, Renzo; Gleeson, Joseph G

    2014-07-01

    Focal cortical dysplasias (FCDs) constitute a prevalent cause of intractable epilepsy in children, and is one of the leading conditions requiring epilepsy surgery. Despite recent advances in the cellular and molecular biology of these conditions, the pathogenetic mechanisms of FCDs remain largely unknown. The purpose if this work is to review the molecular underpinnings of FCDs and to highlight potential therapeutic targets. A systematic review of the literature regarding the histologic, molecular, and electrophysiologic aspects of FCDs was conducted. Disruption of the mammalian target of rapamycin (mTOR) signaling comprises a common pathway underlying the structural and electrical disturbances of some FCDs. Other mechanisms such as viral infections, prematurity, head trauma, and brain tumors are also posited. mTOR inhibitors (i.e., rapamycin) have shown positive results on seizure management in animal models and in a small cohort of patients with FCD. Encouraging progress has been achieved on the molecular and electrophysiologic basis of constitutive cells in the dysplastic tissue. Despite the promising results of mTOR inhibitors, large-scale randomized trials are in need to evaluate their efficacy and side effects, along with additional mechanistic studies for the development of novel, molecular-based diagnostic and therapeutic approaches. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

  19. Quantifying the effect of off-focal radiation on the output of kilovoltage x-ray systems.

    Science.gov (United States)

    Ali, E S M; Rogers, D W O

    2008-09-01

    In a typical x-ray tube, off-focal radiation is mainly generated by the backscattered electrons that reenter the anode outside the focal spot. In this study, BEAMnrc (an EGSnrc user-code) is modified to simulate off-focal radiation. The modified BEAMnrc code is used to study the characteristics of electrons that backscatter from the anode, and to quantify their effect on the output of typical x-ray systems. Results show that the first generation backscatter coefficient is approximately 50% for tungsten anodes at diagnostic energies, and approximately 38% for molybdenum anodes at mammography energies. Second and higher generations of backscatter have a relatively minor contribution. At the patient plane, our simulation results are in excellent agreement with experimental measurements in the literature for the spectral shape of both the primary and the off-focal components, and also for the integral off-focal-to-primary ratio. The spectrum of the off-focal component at the patient plane is softer than the primary, which causes a slight softening in the overall spectrum. For typical x-ray systems, the off-focal component increases patient exposure (for a given number of incident primary electrons) by up to 11% and reduces the half-value layer and the effective energy of the average spectrum by up to 7% and 3%, respectively. The larger effects are for grounded cathode tubes, smaller interelectrode distance, higher tube voltage, lighter filtration, and less collimation. Simulation time increases by approximately 30% when the off-focal radiation is included, but the overall simulation time remains of the order of a few minutes. This study concludes that the off-focal radiation can have a non-negligible effect on the output parameters of x-ray systems and that it should be included in x-ray tube simulations for more realistic modeling of these systems.

  20. Research on Control Process of Large Scale Antenna Back Shelf Making Planeness%大型天线背架制造平面度控制工艺研究

    Institute of Scientific and Technical Information of China (English)

    孙汶; 赵书行; 万忠

    2011-01-01

    大型天线背架是用铝质型材拼焊而成的桁架结构,外廓尺寸为2 639 mm×2 620 mm×230mm,长、宽度足寸较大,厚度尺寸较小,刚度低,焊接、加工等都会产生较大的变形.天线背架顶部由380个槽的槽底组成平面的平面度要求为0.25 mm.控制制造过程中的变形,特别是控制加工380个槽的变形,保证其槽底的平面度0.25 mm的要求,是制造天线背架的核心,也是工艺的难点.本文阐述了天线背架制造过程中,控制变形的工艺流程和工艺手段,重点阐述了380个槽加工及保证槽底平面度的夹具,以及其设计原理和调整方法.%Large scale back shelf is the truss work through welding of aluminium proximate matter, the scale of gabarit is 2 639×2 620×230 nun. The length and the width are big but the thickness is small and rigidity is low that make the weld and process generating more deformation. The planeness requiement of plane formed by bottoms of 380 grooves of antenna back shelf top is 0. 25 mm. Must control the deformation under the manufacturing, especaily the deformation of 380 groovesi make sue of the requiemnts of 0. 25 mm of planeness of groove bottoms, it is the core and the difficulty pointe of making antenna back shelf. The paper described the process fiow and process ways of controlling deformation under making process of antenna back shelf, presented the process of 380 grooves and clamp of ensuring planeness of groove bottoms in details and also gave the desigh principle and adusting way.