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Sample records for adjacent focal planes

  1. SNAP focal plane

    SciTech Connect

    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.

  2. SNAP Satellite Focal Plane Development

    SciTech Connect

    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.

  3. Smov Baseline Focal Plane Check

    NASA Astrophysics Data System (ADS)

    Gilmozzi, Roberto

    1994-01-01

    This test will be executed during the period after the servicing mission and before the extension of the COSTAR assembly. Its purpose is to verify that the FOS, HRS, and FOC focal planes have not been altered by the activities performed by Story and the Astronauts during the servicing mission. A large unknown deviation in aperture position would severly impact subsequent COSTAR alignment activities. If this test reveals a deviation, we may be able to compensate for any offsets prior to the complex and delicate COSTAR alignment calibrations. This enhanced version of the Heptathlon is designed to verify course alignments and measure relative aperture positions to within a few arcsecs. SPECIAL REQUIREMENTS: ***This test uses pre-servicing parameters for HRS, FOS, and FOC and the Cycle 4 parameters for WFPC2.*** ***This test requires special alignment and special guide stars.** ***This test requires special commanding for telemetry setups.**

  4. RF/Optical Demonstration: Focal Plane Assembly

    NASA Astrophysics Data System (ADS)

    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.

  5. Digital scanner infrared focal plane technology

    NASA Astrophysics Data System (ADS)

    Ortiz, M. A.; Malone, N. R.; Harris, M.; Shin, J.; Byers, S.; Price, D.; Vampola, J.

    2011-09-01

    Advancements in finer geometry and technology advancements in circuit design now allow placement of digital architecture on cryogenic focal planes while using less power than heritage analog designs. These advances in technology reduce the size, weight, and power of modern focal planes. In addition, the interface to the focal plane is significantly simplified and is more immune to Electromagnetic Interference (EMI). The cost of the customer's instrument after integration with the digital scanning Focal Plane Array (FPA) has been significantly reduced by placing digital architecture such as Analog to digital convertors and Low Voltage Differential Signaling (LVDS) Inputs and Outputs (I/O) on the Read Out Integrated Circuit (ROIC).

  6. Mosaic focal plane for star sensors

    NASA Astrophysics Data System (ADS)

    Chang, N. C.

    1981-02-01

    The basic principles of star sensors are reviewed with reference to the advantages of replacing photodiodes, image dissectors, and vidicons with mosaic charge transfer device (CTD) focal planes. The desirable characteristics of CTD focal planes include: high uniformity, high transfer effect, low dark current, low hot and cold spots, low dead space, low angular misalignment, high coplanarity, and high thermal stability. An implementation of a mosaic CTD array star sensor which achieves high angular position accuracy and frequency attitude update is presented. Two focal plane packaging concepts, the planar and vertical board packagings, are examined.

  7. Focal Plane Metrology for the LSST Camera

    SciTech Connect

    A Rasmussen, Andrew P.; Hale, Layton; Kim, Peter; Lee, Eric; Perl, Martin; Schindler, Rafe; Takacs, Peter; Thurston, Timothy; /SLAC

    2007-01-10

    Meeting the science goals for the Large Synoptic Survey Telescope (LSST) translates into a demanding set of imaging performance requirements for the optical system over a wide (3.5{sup o}) field of view. In turn, meeting those imaging requirements necessitates maintaining precise control of the focal plane surface (10 {micro}m P-V) over the entire field of view (640 mm diameter) at the operating temperature (T {approx} -100 C) and over the operational elevation angle range. We briefly describe the hierarchical design approach for the LSST Camera focal plane and the baseline design for assembling the flat focal plane at room temperature. Preliminary results of gravity load and thermal distortion calculations are provided, and early metrological verification of candidate materials under cold thermal conditions are presented. A detailed, generalized method for stitching together sparse metrology data originating from differential, non-contact metrological data acquisition spanning multiple (non-continuous) sensor surfaces making up the focal plane, is described and demonstrated. Finally, we describe some in situ alignment verification alternatives, some of which may be integrated into the camera's focal plane.

  8. Solid-state curved focal plane arrays

    NASA Technical Reports Server (NTRS)

    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.

  9. Achromatic phase shifting focal plane masks

    NASA Astrophysics Data System (ADS)

    Newman, Kevin

    The search for life on other worlds is an exciting scientific endeavor that could change the way we perceive our place in the universe. Thousands of extrasolar planets have been discovered using indirect detection techniques. One of the most promising methods for discovering new exoplanets and searching for life is direct imaging with a coronagraph. Exoplanet coronagraphy of Earth-like planets is a challenging task, but we have developed many of the tools necessary to make it feasible. The Phase-Induced Amplitude Apodization (PIAA) Coronagraph is one of the highest-performing architectures for direct exoplanet imaging. With a complex phase-shifting focal plane mask, the PIAA Complex Mask Coronagraph (PIAACMC) can approach the theoretical performance limit for any direct detection technique. The architecture design is flexible enough to be applied to any arbitrary aperture shape, including segmented and obscured apertures. This is an important feature for compatibility with next-generation ground and space-based telescopes. PIAA and PIAACMC focal plane masks have been demonstrated in monochromatic light. An important next step for high-performance coronagraphy is the development of broadband phase-shifting focal plane masks. In this dissertation, we present an algorithm for designing the PIAA and PIAACMC focal plane masks to operate in broadband. We also demonstrate manufacturing of the focal plane masks, and show laboratory results. We use simulations to show the potential performance of the coronagraph system, and the use of wavefront control to correct for mask manufacturing errors. Given the laboratory results and simulations, we show new areas of exoplanet science that can potentially be explored using coronagraph technology. The main conclusion of this dissertation is that we now have the tools required to design and manufacture PIAA and PIAACMC achromatic focal plane masks. These tools can be applied to current and future telescope systems to enable new

  10. MTI Focal Plane Assembly Design and Performance

    SciTech Connect

    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.

  11. Optical interconnections to focal plane arrays

    SciTech Connect

    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.

  12. Dual band QWIP focal plane array

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath D. (Inventor); Choi, Kwong Kit (Inventor); Bandara, Sumith V. (Inventor)

    2005-01-01

    A quantum well infrared photodetector (QWIP) that provides two-color image sensing. Two different quantum wells are configured to absorb two different wavelengths. The QWIPs are arrayed in a focal plane array (FPA). The two-color QWIPs are selected for readout by selective electrical contact with the two different QWIPs or by the use of two different wavelength sensitive gratings.

  13. High speed multi focal plane optical system

    NASA Technical Reports Server (NTRS)

    Minott, P. O. (Inventor)

    1983-01-01

    An apparatus for eliminating beamsplitter generated optical aberrations in a pupil concentric optical system providing a plurality of spatially separated images on different focal planes or surfaces is presented. The system employs a buried surface beamsplitter having spherically curved entrance and exit faces which are concentric to a system aperture stop with the entrance face being located in the path of a converging light beam directed there from an image forming objective element which is also concentric to the aperture stop.

  14. Focal plane scanner with reciprocating spatial window

    NASA Technical Reports Server (NTRS)

    Mao, Chengye (Inventor)

    2000-01-01

    A focal plane scanner having a front objective lens, a spatial window for selectively passing a portion of the image therethrough, and a CCD array for receiving the passed portion of the image. All embodiments have a common feature whereby the spatial window and CCD array are mounted for simultaneous relative reciprocating movement with respect to the front objective lens, and the spatial window is mounted within the focal plane of the front objective. In a first embodiment, the spatial window is a slit and the CCD array is one-dimensional, and successive rows of the image in the focal plane of the front objective lens are passed to the CCD array by an image relay lens interposed between the slit and the CCD array. In a second embodiment, the spatial window is a slit, the CCD array is two-dimensional, and a prism-grating-prism optical spectrometer is interposed between the slit and the CCD array so as to cause the scanned row to be split into a plurality of spectral separations onto the CCD array. In a third embodiment, the CCD array is two-dimensional and the spatial window is a rectangular linear variable filter (LVF) window, so as to cause the scanned rows impinging on the LVF to be bandpass filtered into spectral components onto the CCD array through an image relay lens interposed between the LVF and the CCD array.

  15. Integrated focal-plane array /IFPA/ approach to large-area infrared focal plane architecture

    NASA Astrophysics Data System (ADS)

    Warren, R. E.

    1980-01-01

    A modular approach to IFPA design is presented which makes it possible to obtain a high-density infrared focal plane amendable to parallel manufacturing techniques as well as to serial plane integration and test. The percent fill factor of the design is dependent on the dimension of the individual detectors; each submodule is manufactured from identical components. The technologies including cables, interconnects, multilayer interconnect structures, and subassembly test requirements, which have direct application to scanning as well as staring integrated focal plane arrays, are discussed.

  16. Characterization of DECam focal plane detectors

    SciTech Connect

    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.

  17. The Simbol-X Focal Plane

    NASA Astrophysics Data System (ADS)

    Laurent, P.

    2009-05-01

    The Simbol-X focal plane is designed to detect photons focused by the mirror in the 0.5 to 100 keV energy band. Composed of two detectors, it will measure the position, energy, and arrival time of each incoming X-ray. On top of it will be a collimator to shield all photons not coming from the mirror field of view. The whole system is surrounded by an active and passive shielding in order to ensure the required very low background.

  18. Error compensation research on the focal plane attitude measurement instrument

    NASA Astrophysics Data System (ADS)

    Zhou, Hongfei; Zhang, Feifan; Zhai, Chao; Zhou, Zengxiang; Liu, Zhigang; Wang, Jianping

    2016-07-01

    The surface accuracy of astronomical telescope focal plate is a key indicator to precision stellar observation. Combined with the six DOF parallel focal plane attitude measurement instrument that had been already designed, space attitude error compensation of the attitude measurement instrument for the focal plane was studied in order to measure the deformation and surface shape of the focal plane in different space attitude accurately.

  19. Phase retrieval in the focal plane

    NASA Astrophysics Data System (ADS)

    Gaessler, W.; Peter, D.; Storz, C.

    Phase retrieval in the focal plane is a very appealing technique, which would simplify the optomechanics of an Adaptive Optics (AO) system a lot and could gain sensitivity under certain conditions. For conventional AO systems the limiting magnitude of the system does not depend on the diameter of the telescope, since any wave front sensor splits the light into sub-apertures, which are in number related to the telescope diameter. Having this in mind the phase retrieval technique looks promising as it breaks this paradigm in the diffraction limited case and thus yields some gain in limiting magnitude with larger telescope diameter. Until now this path was not followed deeply in astronomical AO systems, as the solution of the inversion is non unique and demands much higher calculation power as in conventional AO. This might change with state of the art computers. We give a short overview of some existing techniques and algorithms of focal plane AO and report results of other groups, which tested them in laboratory and on sky. To solve the drawback of the large computational demands and to increase the sensitivity we propose a bootstrapping process with dynamical binning.

  20. Smart trigger logic for focal plane arrays

    DOEpatents

    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.

  1. Design of large aperture focal plane shutter

    NASA Astrophysics Data System (ADS)

    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.

  2. Stabilized dispersive focal plane systems for space

    NASA Astrophysics Data System (ADS)

    Roming, Peter W. A.; Bayless, Amanda J.; Beebe, Chip R.; Brooks, Mark J.; Davis, Michael W.; Klar, Robert A.; Roberts, John M.; Rose, Randall J.; Winters, Gregory S.

    2012-09-01

    As the costs of space missions continue to rise, the demand for compact, low mass, low-cost technologies that maintain high reliability and facilitate high performance is increasing. One such technology is the stabilized dispersive focal plane system (SDFPS). This technology provides image stabilization while simultaneously delivering spectroscopic or direct imaging functionality using only a single optical path and detector. Typical systems require multiple expensive optical trains and/or detectors, sometimes at the expense of photon throughput. The SDFPS is ideal for performing wide-field low-resolution space-based spectroscopic and direct-imaging surveys. In preparation for a suborbital flight, we have built and ground tested a prototype SDFPS that will concurrently eliminate unwanted image blurring due to the lack of adequate platform stability, while producing images in both spectroscopic and direct-imaging modes. We present the overall design, testing results, and potential scientific applications.

  3. ORFEUS focal plane instrumentation: The Berkeley spectrometer

    NASA Technical Reports Server (NTRS)

    Hurwitz, Mark; Bowyer, Stuart

    1988-01-01

    A spectrograph for the ORFEUS mission that incorporates four varied line-space, spherically figured diffraction gratings was designed. The ORFEUS, a 1-m normal incidence telescope is equipped with 2 focal plane spectrographs. The Berkeley spectrograph was developed with an optimizing raytracing computer code. Each grating accepts the light from 20 percent of the aperture of the telescope primary mirror and has a unique set of characteristics to cover a sub-bandpass within the 390 to 1200 A spectral range. Two photon-counting detectors incorporating a time delay readout system are used to record the spectra from all four gratings simultaneously. The nominal design achieves a spectral resolution (FWHM) in excess of 5500 at all wavelengths within the bandpass. The resolution is limited primarily by the detector spatial resolution. The 1 sigma astigmatism of this design varies between 13 and 150 micrometer on the same focal surface. An independent, direct imaging system tracks the drift of the target within the spectrometer aperture and allows measurement of the misalignment between the telescope optical axis and that of the external star tracker. The resolution and astigmatism achievable with this design are superior to those of a standard Rowland spectrograph designed with the same constraints.

  4. Multiwavelength infrared focal plane array detector

    NASA Technical Reports Server (NTRS)

    Forrest, Stephen R. (Inventor); Olsen, Gregory H. (Inventor); Kim, Dong-Su (Inventor); Lange, Michael J. (Inventor)

    1995-01-01

    A multiwavelength focal plane array infrared detector is included on a common substrate having formed on its top face a plurality of In.sub.x Ga.sub.1-x As (x.ltoreq.0.53) absorption layers, between each pair of which a plurality of InAs.sub.y P.sub.1-y (y<1) buffer layers are formed having substantially increasing lattice parameters, respectively, relative to said substrate, for preventing lattice mismatch dislocations from propagating through successive ones of the absorption layers of decreasing bandgap relative to said substrate, whereby a plurality of detectors for detecting different wavelengths of light for a given pixel are provided by removing material above given areas of successive ones of the absorption layers, which areas are doped to form a pn junction with the surrounding unexposed portions of associated absorption layers, respectively, with metal contacts being formed on a portion of each of the exposed areas, and on the bottom of the substrate for facilitating electrical connections thereto.

  5. HgCdTe hybrid focal plane

    NASA Astrophysics Data System (ADS)

    Rode, J. P.

    1984-09-01

    Second-generation IR systems, consisting of 2-D mosaics of IR detectors, have been under intense development for the last few years. One of the most successful architectures has been a HgCdTe hybrid focal plane array (FPA), using a Si charge-coupled device (CCD) readout chip interfaced to epitaxial HgCdTe. Detection is made by backside-illuminated photovoltaic detectors with high fill factors and quantum efficiency. The detectors are coupled into the CCD by In bumps which mass bond each detector in the mosaic to a CCD input. Advances have been made in uniform, large area HgCdTe detector material that can be grown with a bandgap from less than 0.1 eV to greater than 1 eV. CCD architectures have been developed with simple, linear inputs and dynamic ranges up to 80 dB. Hybrid FPAs are currently being tested in prototype imaging systems, for detecting thermal differences as well as reflected sunlight in the IR. In the 3-5μm region, these arrays have proven capable of noise-equivalent temperature differences as low as 0.01 K, acquired at a 400 Hz frame rate. In addition to improving current imaging systems, these area arrays allow new system concepts to be brought to fruition.

  6. Advanced dynamic pyroelectric focal plane array

    NASA Astrophysics Data System (ADS)

    Unglaub, Ricardo A. G.; Celinska, Jolanta B.; McWilliams, Christopher R.; Paz de Araujo, Carlos A.; Forbes, Timothy; Pankin, Jayson D.

    2010-04-01

    The pyroelectric effect has been characterized for single-pixel elements consisting of strontium bismuth tantalate (SBT) ferroelectric material as the sensing elements. These pixels have been integrated into second-generation focal plane arrays. The constituent second-generation pixels include thermal insulating layers and an infrared absorber layer. The MEMS-less arrays are operated in active mode, a technique that eliminates radiation choppers found in other passive pyroelectric IR imagers. This paper addresses the results of precursor 2x2 to 14x14 second-generation arrays of SBT elements, the active detection mechanism, and the unique read-out, interrogation signal, and the synchronization electronics. The second-generation 14x14 pixels array was implemented to demonstrate the performance of an active pyroelectric array as a precursor to larger size arrays using different pixel dimensions. The active mode detection eliminates the use of a chopper, enables the dynamic partition of the array into pixel domains in which pixel sensitivity in the domains can be adjusted independently. This unique feature in IR detection can be applied to the simultaneous tracking of diverse contrast objects. In addition, by controlling the thickness of the absorber material the arrays can be optimized for maximum response at specified wavelengths by means of quarter-wavelength interferometry.

  7. Deep ultraviolet (254 nm) focal plane array

    NASA Astrophysics Data System (ADS)

    Cicek, Erdem; Vashaei, Zahra; McClintock, Ryan; Razeghi, Manijeh

    2011-10-01

    We report the synthesis, fabrication and testing of a 320 × 256 focal plane array (FPA) of back-illuminated, solarblind, p-i-n, AlxGa1-xN-based detectors, fully realized within our research laboratory. We implemented a novel pulsed atomic layer deposition technique for the metalorganic chemical vapor deposition (MOCVD) growth of crackfree, thick, and high Al composition AlxGa1-xN layers. Following the growth, the wafer was processed into a 320 × 256 array of 25 μm × 25 μm pixels on a 30 μm pixel-pitch and surrounding mini-arrays. A diagnostic mini-array was hybridized to a silicon fan-out chip to allow the study of electrical and optical characteristics of discrete pixels of the FPA. At a reverse bias of 1 V, an average photodetector exhibited a low dark current density of 1.12×10-8 A/cm2. Solar-blind operation is observed throughout the array with peak detection occurring at wavelengths of 256 nm and lower and falling off three orders of magnitude by 285 nm. After indium bump deposition and dicing, the FPA is hybridized to a matching ISC 9809 readout integrated circuit (ROIC). By developing a novel masking technology, we significantly reduced the visible response of the ROIC and thus the need for external filtering to achieve solar- and visible-blind operation is eliminated. This allowed the FPA to achieve high external quantum efficiency (EQE): at 254 nm, average pixels showed unbiased peak responsivity of 75 mA/W, which corresponds to an EQE of ~37%. Finally, the uniformity of the FPA and imaging properties are investigated.

  8. Compact Focal Plane Assembly for Planetary Science

    NASA Technical Reports Server (NTRS)

    Brown, Ari; Aslam, Shahid; Huang, Wei-Chung; Steptoe-Jackson, Rosalind

    2013-01-01

    A compact radiometric focal plane assembly (FPA) has been designed in which the filters are individually co-registered over compact thermopile pixels. This allows for construction of an ultralightweight and compact radiometric instrument. The FPA also incorporates micromachined baffles in order to mitigate crosstalk and low-pass filter windows in order to eliminate high-frequency radiation. Compact metal mesh bandpass filters were fabricated for the far infrared (FIR) spectral range (17 to 100 microns), a game-changing technology for future planetary FIR instruments. This fabrication approach allows the dimensions of individual metal mesh filters to be tailored with better than 10- micron precision. In contrast, conventional compact filters employed in recent missions and in near-term instruments consist of large filter sheets manually cut into much smaller pieces, which is a much less precise and much more labor-intensive, expensive, and difficult process. Filter performance was validated by integrating them with thermopile arrays. Demonstration of the FPA will require the integration of two technologies. The first technology is compact, lightweight, robust against cryogenic thermal cycling, and radiation-hard micromachined bandpass filters. They consist of a copper mesh supported on a deep reactive ion-etched silicon frame. This design architecture is advantageous when constructing a lightweight and compact instrument because (1) the frame acts like a jig and facilitates filter integration with the FPA, (2) the frame can be designed so as to maximize the FPA field of view, (3) the frame can be simultaneously used as a baffle for mitigating crosstalk, and (4) micron-scale alignment features can be patterned so as to permit high-precision filter stacking and, consequently, increase the filter bandwidth and sharpen the out-of-band rolloff. The second technology consists of leveraging, from another project, compact and lightweight Bi0.87Sb0.13/Sb arrayed thermopiles

  9. Test chamber for low-background IR focal plane testing

    NASA Technical Reports Server (NTRS)

    Staller, Craig; Capps, Richard W.; Butler, Douglas; Moss, Nancy; Norwood, Wynn

    1989-01-01

    A unique and versatile vacuum chamber has been designed for JPL's IR Focal Plane Technology Group. This chamber is equipped with multiple ports for cryogen and electrical vacuum feedthroughs, pumping units, vacuum gages, sources, and detector camera heads. The design incorporates a liquid-nitrogen-cooled optical table and radiation shield for low-background IR detector testing. Focal planes can be tested at temperatures ranging from 300 K to that of liquid helium. This paper describes the design and construction of this low-background IR focal plane test chamber and discusses some of its distinctive features. An analysis of the test chamber's performance is also presented.

  10. Radiation-Induced Transient Effects in Near Infrared Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Reed, Robert A.; Pickel, J.; Marshall, P.; Waczynski, A.; McMurray, R.; Gee, G.; Polidan, E.; Johnson, S.; McKeivey, M.; Ennico, K.; Johnson, R.

    2004-01-01

    This viewgraph presentation describes a test simulate the transient effects of cosmic ray impacts on near infrared focal plane arrays. The objectives of the test are to: 1) Characterize proton single events as function of energy and angle of incidence; 2) Measure charge spread (crosstalk) to adjacent pixels; 3) Assess transient recovery time.

  11. Orion: The Largest Infrared Hybrid Focal Plane in Production

    NASA Astrophysics Data System (ADS)

    Fowler, Albert M.; Merrill, Michael; Ball, William J.; Henden, Arne A.; Vrba, Frederick J.; McCreight, Craig R.

    2003-03-01

    Orion is a program to develop a 2048x2048 infrared focal plane using InSb PV detectors. It is the natural follow-on to the successful Aladdin 1024x1024 program, which was the largest IR focal plane of the 90's. Although the pixels are somewhat smaller than Aladdin, the overall focal plane is over 50mm in size and for the present is the largest IR focal plane of the 21st century. The work is being done by Raytheon Infrared Operations (RIO but better known as SBRC) by many of the same people who created the Aladdin focal plane. The design is very similar to the successful Aladdin design with the addition of reference pixels to lower noise and drift effects in long integrations. So far we have made five focal plane modules with hybridized InSb detectors. In this paper we will discuss the unique design features of this device as well as present test data taken from these devices.

  12. Cryogenic focal plane flatness measurement with optical zone slope tracking

    NASA Astrophysics Data System (ADS)

    Edelstein, Jerry; Sirk, Martin; Jelinsky, Patrick N.; Besuner, Robert W.; Hoff, Matthew; Perry, Paul; Heetderks, Henry D.; Bebek, Christopher J.; Levi, Michael E.

    2011-10-01

    We describe a non-contact optical measurement method used to determine the surface flatness of a cryogenic sensor array developed for the JDEM mission. Large focal planes envisioned for future visible to near infra-red astronomical large area point-source surveys such as JDEM, WFIRST, or EUCLID must operate at cryogenic temperatures while maintaining focal plane flatness within a few 10's of μm over half-meter scales. These constraints are imposed by sensitivity conditions that demand low noise observations from the sensors and the large-field, fast optical telescopes necessary to obtain the science yield. Verifying cryogenic focal plane flatness is challenging because μm level excursions need to be measured within and across many multi-cm sized sensors using no physical contact and while situated within a high-vacuum chamber. We have used an optical metrology Shack-Hartmann scheme to measure the 36x18 cm focal plane developed for the JDEM mission at the Lawrence Berkeley National Laboratory. The focal plane holds a 4x8 array of CCDs and HgCdTe detectors. The flatness measurement scheme uses a telescope-fed micro-lens array that samples the focal plane to determine slope changes of individual sensor zones.

  13. Monolithically integrated HgCdTe focal plane arrays

    NASA Astrophysics Data System (ADS)

    Velicu, Silviu; Lee, Tae-Seok; Ashokan, Renganathan; Grein, Christoph H.; Boieriu, Paul; Chen, Y. P.; Dinan, John H.; Lianos, Dimitrios

    2003-12-01

    The cost and performance of hybrid HgCdTe infrared focal plane arrays are constrained by the necessity of fabricating the detector arrays on a CdZnTe substrate. These substrates are expensive, fragile, are available only in small rectangular formats, and are not a good thermal expansion match to the silicon readout integrated circuit. We discuss in this paper an infrared sensor technology based on monolithically integrated infrared focal plane arrays that could replace the conventional hybrid focal plane array technology. We have investigated the critical issues related to the growth of HgCdTe on Si read-out integrated circuits and the fabrication of monolithic focal plane arrays: (1) the design of Si read-out integrated circuits and focal plane array layouts, (2) the low temperature cleaning of Si(001) wafers, (3) growth of CdTe and HgCdTe layers on read-out integrated circuits, (4) array fabrication, interconnection between focal plane array and read-out integrated circuit input nodes and demonstration of the photovoltaic operation, and (5) maintenance of the read-out integrated circuit characteristics after substrate cleaning, molecular beam epitaxy growth and device fabrication. Crystallographic, optical and electrical properties of the grown layers are presented. Electrical properties for diodes fabricated on misoriented Si and read-out integrated circuit substrates are discussed. The fabrication of arrays with demonstrated I-V properties show that monolithic integration of HgCdTe-based infrared focal plane arrays on Si read-out integrated circuits is feasible and could be implemented in the 3rd generation of infrared systems.

  14. Orion: A 1-5 Micron Focal Plane for the 21st Century

    NASA Astrophysics Data System (ADS)

    Fowler, A. M.; Merrill, K. M.; Ball, W.; Henden, A.; Vrba, F.; McCreight, C.

    The Orion program is a project to develop a 2Kx2K infrared focal plane using InSb p-on-n diodes for detectors. It is the natural follow-up to the successful Aladdin 1Kx1K program started in the early 90's. The work is being done at the Raytheon Infrared Operations Division (RIO, previously known as the Santa Barbara Research Center) by many of the same people who created the Aladdin focal plane. The design is very similar to the successful Aladdin design with the addition of reference pixels, whole array readout (no quadrants), two-adjacent-side buttability, and a packaging design that includes going directly to the ultimate focal plane size of 4Kx4K. So far we have successfully made a limited number of hybrid modules with InSb detectors. In this paper we will describe the design features and test data taken from some of these devices.

  15. LiteBIRD: Mission Overview and Focal Plane Layout

    NASA Astrophysics Data System (ADS)

    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.

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

    DTIC Science & Technology

    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

  17. Tissue microenvironments within functional cortical subdivisions adjacent to focal stroke.

    PubMed

    Katsman, Diana; Zheng, Jian; Spinelli, Kateri; Carmichael, S Thomas

    2003-09-01

    Stroke produces a region of complete cell death and areas of partial damage, injury, and gliosis. The spatial relationship of these regions of damage to the infarct core and within spared neuronal circuits has not been identified. A model of cortical stroke was developed within functional subsets of the somatosensory cortex. Infarct size, regions of apoptosis, oxidative DNA damage, heat shock protein induction, and subtypes of reactive gliosis were precisely mapped with the somatosensory body map, quantified, and interrelated. Three tissue microenvironments were recognized: zones of partial ischemic damage, heat shock protein induction, and distributed gliosis. These three zones involved progressively more distant cortical regions, each larger than the infarct core. The zone of partial ischemic damage represents an overlap region of apoptotic cell death, oxidative DNA damage, loss of synaptic connections, and local reactive gliosis. The zone of distributed gliosis occupies distinct functional areas of the somatosensory cortex. The tissue reorganization induced by stroke is much larger than the stroke site itself. Adjacent tissue microenvironments are sites of distinct reactive cellular signaling and may serve as a link between the processes of acute cell death and delayed neuronal plasticity after focal stroke.

  18. Design study of the accessible focal plane telescope for shuttle

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The design and cost analysis of an accessible focal plane telescope for Spacelab is presented in blueprints, tables, and graphs. Topics covered include the telescope tube, the telescope mounting, the airlock plus Spacelab module aft plate, the instrument adapter, and the instrument package. The system allows access to the image plane with instrumentation that can be operated by a scientist in a shirt sleeve environment inside a Spacelab module.

  19. Prototype focal plane assembly for multispectral remote sensing

    SciTech Connect

    Rienstra, J.L.; Vampola, J.A.

    1995-09-01

    Sandia National Laboratories and several subsystem contractors are developing technologies applicable to multispectral remote sensing. A prototype multispectral sensor system is under development. The three major subsystems making up the prototype sensor are the focal plane assembly (FPA), the cryocooler, and the telescope. This paper covers the focal plane assembly, which is the basis of the sensor system. The focal plane assembly includes sensor chip assemblies, optical filters, and a vacuum enclosure with cold shielding The optical filters define 15 spectral bands in a range from 0.45 {mu}m to 10.7 {mu}m. All the linear arrays are mounted on a single motherboard and are designed to operate at 75 K. The four spectral bands covering the visible to near infrared have roughly 2400 pixels each, and the remaining 11 spectral bands have roughly 600 pixels each. The average total rate of multispectral data from the FPA is approximately 16.4 megapixels per second. The diverse requirements for the focal plane assembly make this a challenging, sensor to design and build.

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

    NASA Technical Reports Server (NTRS)

    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.

  1. Multispectral Focal Plane Assembly for Satellite Remote Sensing

    SciTech Connect

    Rienstra, J.; Ballard, M.

    1997-12-31

    Sandia National Laboratories and several subsystem contractors are developing technologies applicable to multispectral remote sensing from space. A proof of concept multispectral sensor system is under development. The objective of building this sensor is to demonstrate and evaluate multispectral imaging technologies for various applications. The three major subsystems making up the sensor are the focal plane assembly (FPA), the cryocooler, and the telescope. This paper covers the focal plane assembly, which is the basis of the sensor system. The focal plane assembly includes sensor chip assemblies, optical filters, and a vacuum enclosure with cold shielding. Linear detector arrays provide spatial resolution in the cross-track direction for a pushbroom imager configuration. The optical filters define 15 spectral bands in a range from 0.45 microns to 10.7 microns. All the detector arrays are mounted on a single focal plane and are designed to operate at 75 K. No beam splitters are used. The four spectral bands covering the visible to near infrared have roughly 2400 pixels each, and the remaining 11 spectral bands have roughly 600 pixels each. The average total rate of multispectral data from the FPA is approximately 15.4 megapixels per second. At the time this paper is being written, the multispectral focal plane assembly is in the fabrication phase. A thermal/mechanical mockup has been built and tested for the vibration environment and to determine the thermal load. Some of the sensor chip assemblies and filters have been built and tested. Several notable features of the design are covered in the paper as well as preliminary test data.

  2. Signal processing on the focal plane array: an overview

    NASA Astrophysics Data System (ADS)

    Graham, Roger W.; Trautfield, Walter C.; Taylor, Scott M.; Murray, Mark P.; Mesh, Frank J.; Horn, Stuart B.; Finch, James A.; Dang, Khoa V.; Caulfield, John T.

    2000-12-01

    Raytheon's Infrared Operations (RIO) has invented and developed a new class of focal plane arrays; the Adaptive IR Sensor (AIRS) and Thinfilm Analog Image Processor (TAIP). The AIRS FPA is based upon biologically inspired on-focal- plane circuitry, which adaptively removes detector and optic temperature drift and l/f induced fixed pattern noise. This third-generation multimode IRFPA, also called a Smart FPA, is a 256x256-array format capable of operation in four modes: 1) Direct Injection (DI), 2) Adaptive Non-uniformity Correction (NUC), 3) Motion/Edge Detection, and 4) Subframe Averaging. Also the 320x240 TAIP results have shown excellent image processing in the form of Spatial and Temporal processing.

  3. Uncooled infrared focal plane array imaging in China

    NASA Astrophysics Data System (ADS)

    Lei, Shuyu

    2015-06-01

    This article reviews the development of uncooled infrared focal plane array (UIFPA) imaging in China in the past decade. Sensors based on optical or electrical read-out mechanism were developed but the latter dominates the market. In resistive bolometers, VOx and amorphous silicon are still the two major thermal-sensing materials. The specifications of the IRFPA made by different manufactures were collected and compared. Currently more than five Chinese companies and institutions design and fabricate uncooled infrared focal plane array. Some devices have sensitivity as high as 30 mK; the largest array for commercial products is 640×512 and the smallest pixel size is 17 μm. Emphasis is given on the pixel MEMS design, ROIC design, fabrication, and packaging of the IRFPA manufactured by GWIC, especially on design for high sensitivities, low noise, better uniformity and linearity, better stabilization for whole working temperature range, full-digital design, etc.

  4. Precise annealing of focal plane arrays for optical detection

    DOEpatents

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  6. On-chip ADC for infrared focal plane arrays

    NASA Astrophysics Data System (ADS)

    Gao, Lei; Chen, Guo-qiang; Wang, Pan; Ding, Rui-jun

    2013-09-01

    This paper presents a low power and small area analog-digital converter (ADC) for infrared focal plane arrays (IRFPA) readout integrated circuit (ROIC). Successive approximation register (SAR) ADC architecture is used in this IRFPA readout integrated circuit. Each column of the IRFPA shares one SAR ADC. The most important part is the three-level DAC. Compared to the previous design, this three-level DAC needs smaller area, has lower power, and more suitable for IRFPA ROIC. In this DAC, its most significant bit (MSB) sub-DAC uses charge scaling, while the least significant bit (LSB) sub-DAC uses voltage scaling. Where the MSB sub-DAC consists of a four-bit charge scaling DAC and a five-bit sub-charge scaling DAC. We need to put a scaling capacitor Cs between these two sub-DACs. Because of the small area, we have more design methods to make the ADC has a symmetrical structure and has higher accuracy. The ADC also needs a high resolution comparator. In this design the comparator uses three-stage operational amplifier structure to have a 77dB differential gain. As the IR focal plane readout circuit signal is stepped DC signal, the circuit design time without adding the sample and hold circuit, so we can use a DC signal instead of infrared focal plane readout circuit output analog signals to be simulated. The simulation result shows that the resolution of the ADC is 12 bit.

  7. Achromatic Focal Plane Mask for Exoplanet Imaging Coronagraphy

    NASA Technical Reports Server (NTRS)

    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.

  8. Kalman Filter for Calibrating a Telescope Focal Plane

    NASA Technical Reports Server (NTRS)

    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.

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

    SciTech Connect

    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.

  10. Focal plane detectors possible detector technologies for OWL/AIRWATCH

    SciTech Connect

    Flyckt, Esso

    1998-06-15

    New satellite-born projects OWL and AIRWATCH will need single-photon focal-plane detectors of a million pixels in a design which is optimized to the focusing optics and electronics at acceptable cost. We discuss different phototube possibilities and their pros and cons with crude cost estimates. We conclude that a multichannel-photomultiplier solution is safe. A better compromise may be to adapt a 6 or 9 inch X-ray image intensifier tube or develop a 12 inch image intensifier for detecting individual photons, and adapt the optics to have many mirror modules. The possibility of developing super-large-area phototubes is also discussed.

  11. Analysis and modeling for thermal focal plane arrays

    NASA Astrophysics Data System (ADS)

    Tuer, T. W.; Ball, B. W.; Freeling, J. R.; Lennington, J. W.; Lindquist, G. H.

    1984-07-01

    The development of a first principles computer simulation of a generic pyroelectric thermal detector is described. Formulation of the pertinent equations (based on a thorough literature survey) is presented. This simulation incorporates a finite difference treatment of the transient three-dimensional thermal response of composite focal plane arrays, with treatments of the signal generation, readout and processing including all pertinent noise sources. A number of simplified problems having analytical solutions were treated to validate various portions of the simulation to within a few percent. Performance estimates were made for conceptual several configurations and materials.

  12. Orion: A 1 5 Micron Focal Plane for the 21st Century

    NASA Astrophysics Data System (ADS)

    Fowler, Albert M.; Merrill, K. Michael; Ball, William; Henden, Arne; Vrba, Fred; McCreight, Craig

    2002-08-01

    The Orion program is a project to develop a 2K × 2K infrared focal plane using InSb p-on-n diodes for detectors. It is the natural follow-up to the successful Aladdin 1K × 1Kprogram started in the early 90’s. The work is being done at the Raytheon Infrared Operations Division (RIO, previously known as the Santa Barbara Research Center) by many of the same people who created the Aladdin focal plane. The design is very similarto the successful Aladdin design with the addition of reference pixels, whole array readout (no quadrants), two-adjacent-side buttability, and a packaging design that includes going directly to the ultimate focal plane size of 4K × 4K. So far we have successfully made a limited number of hybrid modules with InSb detectors. In this paper we will describe the design features and test data taken from some of these devices.

  13. Radiometric infrared focal plane array imaging system for thermographic applications

    NASA Technical Reports Server (NTRS)

    Esposito, B. J.; Mccafferty, N.; Brown, R.; Tower, J. R.; Kosonocky, W. F.

    1992-01-01

    This document describes research performed under the Radiometric Infrared Focal Plane Array Imaging System for Thermographic Applications contract. This research investigated the feasibility of using platinum silicide (PtSi) Schottky-barrier infrared focal plane arrays (IR FPAs) for NASA Langley's specific radiometric thermal imaging requirements. The initial goal of this design was to develop a high spatial resolution radiometer with an NETD of 1 percent of the temperature reading over the range of 0 to 250 C. The proposed camera design developed during this study and described in this report provides: (1) high spatial resolution (full-TV resolution); (2) high thermal dynamic range (0 to 250 C); (3) the ability to image rapid, large thermal transients utilizing electronic exposure control (commandable dynamic range of 2,500,000:1 with exposure control latency of 33 ms); (4) high uniformity (0.5 percent nonuniformity after correction); and (5) high thermal resolution (0.1 C at 25 C background and 0.5 C at 250 C background).

  14. Continuing developments in biologically inspired smart focal plane concepts

    NASA Astrophysics Data System (ADS)

    McCarley, Paul L.; Wehling, Martin F.; Massie, Mark A.

    1995-05-01

    The Neuromorphic IR FPA Sensor developed by Amber Engineering, Inc., Goleta, CA for the Wright Laboratory Armament Directorate's Advanced Guidance Division, performs a Difference of Gaussians filtering function, similar to what occurs in the outer plexiform layer of the primate retinal system. This function requires a computationally intensive (digital-wise) spatial-temporal data smoothing operation, which is executed on the focal plane, at the seeker frame rate, while the image data is still in the analog domain. Implementation of analog operation provides great flexibility, not only in terms of the speed and power dissipation advantages, but also with the interface of other processes to the analog system. The fact that the human visual system is essentially based upon analog techniques helps to emphasize the point; nature has invested millions of years in the development of sensors and processing `wetware' which are highly tuned to their environment. Our goal is to take further advantage of the lessons which nature can teach us, and advance the state of the art in imaging detection and tracking by taking the next step to develop neuromorphic/corticomorphic focal plane devices. This paper will discuss some of the concepts the authors have been investigation in formulating advanced `smart' FPAs for future guided missile seeker applications.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Curved-Focal-Plane Arrays Using Deformed-Membrane Photodetectors

    NASA Technical Reports Server (NTRS)

    Nikzad, Shouleh; Jones, Todd

    2004-01-01

    A versatile and simple approach to the design and fabrication of curved-focal-plane arrays of silicon-based photodetectors is being developed. This approach is an alternative to the one described in "Curved Focal-Plane Arrays Using Back- Illuminated High-Purity Photodetectors" (NPO-30566), NASA Tech Briefs, Vol. 27, No. 10 (October 2003), page 10a. As in the cited prior article, the basic idea is to improve the performance of an imaging instrument and simplify the optics needed to obtain a given level of performance by making an image sensor (in this case, an array of photodetectors) conform to a curved focal surface, instead of designing the optics to project an image onto a flat focal surface. There is biological precedent for curved-focal-surface designs: retinas - the image sensors in eyes - conform to the naturally curved focal surfaces of eye lenses. The present approach is applicable to both front-side- and back-side-illuminated, membrane photodetector arrays and is being demonstrated on charge-coupled devices (CCDs). The very-large scale integrated (VLSI) circuitry of such a CCD or other array is fabricated on the front side of a silicon substrate, then the CCD substrate is attached temporarily to a second substrate for mechanical support, then material is removed from the back to obtain the CCD membrane, which typically has a thickness between 10 and 20 m. In the case of a CCD designed to operate in back-surface illumination, delta doping can be performed after thinning to enhance the sensitivity. This approach is independent of the design and method of fabrication of the front-side VLSI circuitry and does not involve any processing of a curved silicon substrate. In this approach, a third substrate would be prepared by polishing one of its surfaces to a required focal-surface curvature. A CCD membrane fabricated as described above would be pressed against, deformed into conformity with, and bonded to, the curved surface. The technique used to press and

  17. UV photodetectors, focal plane arrays, and avalanche photodiodes

    NASA Astrophysics Data System (ADS)

    McClintock, Ryan

    2007-12-01

    The study of III-Nitride based optoelectronics devices is a maturing field, but there are still many underdeveloped areas in which to make a contribution of new and original research. This work specifically targets the goals of realizing high-efficiency back-illuminated solar-blind photodetectors, solar-blind focal plane arrays, and visible- and solar-blind Avalanche photodiodes. Achieving these goals has required systematic development of the material growth and characterization, device modeling and design, device fabrication and processing, and the device testing and qualification. This work describes the research conducted and presents relevant devices results. The AlGaN material system has a tunable direct bandgap that is ideally suited to detection of ultraviolet light, however this material system suffers from several key issues, making realization of high-efficiency photodetectors difficult: large dislocation densities, low n-type and p-type doping efficiency, and lattice and thermal expansion mismatches leading to cracking of the material. All of these problems are exacerbated by the increased aluminum compositions necessary in back-illuminated and solar-blind devices. Overcoming these obstacles has required extensive development and optimization of the material growth techniques necessary: this includes everything from the growth of the buffer and template, to the growth of the active region. The broad area devices realized in this work demonstrate a quantum efficiency that is among the highest ever reported for a back-illuminated solar-blind photodetector (responsivity of 157 mA/W at 280nm, external quantum efficiency of 68%). Taking advantage of the back illuminated nature of these detectors, we have successfully developed the technology to hybridize and test a solar-blind focal plane array camera. The initial focal plane array shows good uniformity and reasonable operability, and several images from this first camera are presented. However, in order to

  18. Integrated focal plane arrays for millimeter-wave astronomy

    NASA Astrophysics Data System (ADS)

    Bock, James J.; Goldin, Alexey; Hunt, Cynthia; Lange, Andrew E.; Leduc, Henry G.; Day, Peter K.; Vayonakis, Anastasios; Zmuidzinas, Jonas

    2002-02-01

    We are developing focal plane arrays of bolometric detectors for sub-millimeter and millimeter-wave astrophysics. We propose a flexible array architecture using arrays of slot antennae coupled via low-loss superconducting Nb transmission line to microstrip filters and antenna-coupled bolometers. By combining imaging and filtering functions with transmission line, we are able to realize unique structures such as a multi-band polarimeter and a planar, dispersive spectrometer. Micro-strip bolometers have significantly smaller active volume than standard detectors with extended absorbers, and can realize higher sensitivity and speed of response. The integrated array has natural immunity to stray radiation or spectral leaks, and minimizes the suspended mass operating at 0.1-0.3 K. We also discuss future space-borne spectroscopy and polarimetry applications. .

  19. Blocked impurity band hybrid infrared focal plane arrays for astronomy

    NASA Technical Reports Server (NTRS)

    Reynolds, D. B.; Seib, D. H.; Stetson, S. B.; Herter, T.; Rowlands, N.

    1989-01-01

    High-performance infrared hybrid focal plane arrays using 10- x 50-element Si:As blocked-impurity-band (BIB) detectors (cutoff wavelength = 28 microns) and matching switched MOSFET multiplexers have been developed and characterized for space astronomy. Use of impurity-band-conduction technology provides detectors which are nuclear-radiation-hard and free of the many anomalies associated with conventional silicon photoconductive detectors. Emphasis in the present work is on recent advances in detector material quality which have led to significantly improved detector and hybrid characteristics. Results demonstrating increased quantum efficiency (particularly at short-wavelength infrared), obtained by varying the BIB detector properties (infrared active layer thickness and arsenic doping profile), are summarized. Measured read noise and dark current for different temperatures are reported. The hybrid array performance achieved demonstrates that BIB detectors are well suited for use in astronomical instrumentation.

  20. Robust Approach for Nonuniformity Correction in Infrared Focal Plane Array

    PubMed Central

    Boutemedjet, Ayoub; Deng, Chenwei; Zhao, Baojun

    2016-01-01

    In this paper, we propose a new scene-based nonuniformity correction technique for infrared focal plane arrays. Our work is based on the use of two well-known scene-based methods, namely, adaptive and interframe registration-based exploiting pure translation motion model between frames. The two approaches have their benefits and drawbacks, which make them extremely effective in certain conditions and not adapted for others. Following on that, we developed a method robust to various conditions, which may slow or affect the correction process by elaborating a decision criterion that adapts the process to the most effective technique to ensure fast and reliable correction. In addition to that, problems such as bad pixels and ghosting artifacts are also dealt with to enhance the overall quality of the correction. The performance of the proposed technique is investigated and compared to the two state-of-the-art techniques cited above. PMID:27834893

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  4. Strained layer superlattice focal plane array having a planar structure

    DOEpatents

    Kim, Jin K; Carroll, Malcolm S; Gin, Aaron; Marsh, Phillip F; Young, Erik W; Cich, Michael J

    2012-10-23

    An infrared focal plane array (FPA) is disclosed which utilizes a strained-layer superlattice (SLS) formed of alternating layers of InAs and In.sub.xGa.sub.1-xSb with 0.ltoreq.x.ltoreq.0.5 epitaxially grown on a GaSb substrate. The FPA avoids the use of a mesa structure to isolate each photodetector element and instead uses impurity-doped regions formed in or about each photodetector for electrical isolation. This results in a substantially-planar structure in which the SLS is unbroken across the entire width of a 2-D array of the photodetector elements which are capped with an epitaxially-grown passivation layer to reduce or eliminate surface recombination. The FPA has applications for use in the wavelength range of 3-25 .mu.m.

  5. Integration of IR focal plane arrays with massively parallel processor

    NASA Astrophysics Data System (ADS)

    Esfandiari, P.; Koskey, P.; Vaccaro, K.; Buchwald, W.; Clark, F.; Krejca, B.; Rekeczky, C.; Zarandy, A.

    2008-04-01

    The intent of this investigation is to replace the low fill factor visible sensor of a Cellular Neural Network (CNN) processor with an InGaAs Focal Plane Array (FPA) using both bump bonding and epitaxial layer transfer techniques for use in the Ballistic Missile Defense System (BMDS) interceptor seekers. The goal is to fabricate a massively parallel digital processor with a local as well as a global interconnect architecture. Currently, this unique CNN processor is capable of processing a target scene in excess of 10,000 frames per second with its visible sensor. What makes the CNN processor so unique is that each processing element includes memory, local data storage, local and global communication devices and a visible sensor supported by a programmable analog or digital computer program.

  6. Fast speed MWIR imager for uncooled focal plane array

    NASA Astrophysics Data System (ADS)

    Lin, Liu

    2007-12-01

    Recent advances of uncooled detector technology especially the development of uncooled micro-bolometer array hold promise for us to develop low-cost and compact MWIR earth observation imager. For comparative lower radiometric performance of uncooled focal plane array, fast speed optical system operating in large spectral bands is compatible. In addition, in order to exhibit advantages over imagers based on cooled detector technology, the optical system should be as compact as possible which means fewer elements, smaller size and light weight. In this article, a high speed optical design meeting these requirement is provided with 100mm focal length, F/1 F number,+/-2.5°field of view woking in 3-5um wave band. The fast speed MWIR imager has properties mentioned as follows: First, the optical system utilizes a hybrid system including refractive and diffractive elements. Second, the optical system realizes athermalization in simple passive way through distributing power among the refractive elements. It can work under typical temperature scope from -20°C to 60°C for typical space application. Third, Because of high speed aperture, the design makes use of aspheric surface to correct spherical aberration and spherochromatism .Finally, we use Ge and Si material. instead of expensive ZnS material.

  7. Kalman filtering techniques for focal plane electric field estimation.

    PubMed

    Groff, Tyler D; Jeremy Kasdin, N

    2013-01-01

    For a coronagraph to detect faint exoplanets, it will require focal plane wavefront control techniques to continue reaching smaller angular separations and higher contrast levels. These correction algorithms are iterative and the control methods need an estimate of the electric field at the science camera, which requires nearly all of the images taken for the correction. The best way to make such algorithms the least disruptive to science exposures is to reduce the number required to estimate the field. We demonstrate a Kalman filter estimator that uses prior knowledge to create the estimate of the electric field, dramatically reducing the number of exposures required to estimate the image plane electric field while stabilizing the suppression against poor signal-to-noise. In addition to a significant reduction in exposures, we discuss the relative merit of this algorithm to estimation schemes that do not incorporate prior state estimate history, particularly in regard to estimate error and covariance. Ultimately the filter will lead to an adaptive algorithm which can estimate physical parameters in the laboratory for robustness to variance in the optical train.

  8. Spitzer Space Telescope: Focal Plane Survey Final Report. Appendix B:; IRAC

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    This final report summarizes the results and accuracies of the Spitzer Space Telescope focal plane survey. Accuracies achieved are compared to the focal plane survey calibration requirements put forth in the SIRTF IOC-SV Mission Plan [14] and pre-flight predictions made in [2]. The results of this focal plane survey are presently being used to support in-flight precision pointing, precision incremental offsets, IRS peakup array calibration, and ground pointing reconstruction...

  9. Advanced simulation methods to detect resonant frequency stack up in focal plane design

    NASA Astrophysics Data System (ADS)

    Adams, Craig; Malone, Neil R.; Torres, Raymond; Fajardo, Armando; Vampola, John; Drechsler, William; Parlato, Russell; Cobb, Christopher; Randolph, Max; Chiourn, Surath; Swinehart, Robert

    2014-09-01

    Wire used to connect focal plane electrical connections to external electrical circuitry can be modeled using the length, diameter and loop height to determine the resonant frequency. The design of the adjacent electric board and mounting platform can also be analyzed. The combined resonant frequency analysis can then be used to decouple the different component resonant frequencies to eliminate the potential for metal fatigue in the wires. It is important to note that the nominal maximum stress values that cause metal fatigue can be much less than the ultimate tensile stress limit or the yield stress limit and are degraded further at resonant frequencies. It is critical that tests be done to qualify designs that are not easily simulated due to material property variation and complex structures. Sine wave vibration testing is a critical component of qualification vibration and provides the highest accuracy in determining the resonant frequencies which can be reduced or uncorrelated improving the structural performance of the focal plane assembly by small changes in design damping or modern space material selection. Vibration flow down from higher levels of assembly needs consideration for intermediary hardware, which may amplify or attenuate the full up system vibration profile. A simple pass through of vibration requirements may result in over test or missing amplified resonant frequencies that can cause system failure. Examples are shown of metal wire fatigue such as discoloration and microscopic cracks which are visible at the submicron level by the use of a scanning electron microscope. While it is important to model and test resonant frequencies the Focal plane must also be constrained such that Coefficient of Thermal expansion mismatches are allowed to move and not overstress the FPA.

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

    NASA Technical Reports Server (NTRS)

    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.

  11. Imaging Polarimetry With Polarization-Sensitive Focal Planes

    NASA Astrophysics Data System (ADS)

    Vorobiev, Dmitry; Ninkov, Z.

    2014-01-01

    We present a compact, lightweight, snapshot imaging polarimeter designed for operation in the near-infrared (NIR) and mid-infrared (MIR). Flux, polarization and spectral energy distribution are the fundamental measurements through which we infer properties of the sources of radiation such as intensity, temperature, chemical composition, emission mechanisms and structure. In recent decades, many scientific fields that utilize radiometry and spectroscopy have benefited from revolutionary improvements in instrumentation, for example, charge-coupled devices, hybridized infrared arrays, multi-object spectrometers and adaptive optics. Advances in polarimetric instrumentation have been more modest. Recently, the fabrication of microgrid polarizer arrays (MGPAs), facilitated the development of polarization-sensitive focal planes. These devices have inherent capability to measure the degree and angle of polarization across a scene (i.e., imaging polarimetry) instantaneously, without the need for multiple exposures and moving optics or multiple detectors. MGPA-based devices are compact, lightweight, and mechanically robust and perfectly suited for deployment on space-based and airborne platforms. We describe the design, operation and expected performance of MGPA-based imaging polarimeters and identify the applications for which these polarimeters are best suited.

  12. Advancement in 17-micron pixel pitch uncooled focal plane arrays

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Skidmore, George; Howard, Christopher; Clarke, Elwood; Han, C. J.

    2009-05-01

    This paper provides an update of 17 micron pixel pitch uncooled microbolometer development at DRS. Since the introduction of 17 micron pitch 640x480 focal plane arrays (FPAs) in 2006, significant progress has been made in sensor performance and manufacturing processes. The FPAs are now in initial production with an FPA noise equivalent temperature difference (NETD), detector thermal time constant, and pixel operability equivalent or better than that of the current 25 micron pixel pitch production FPAs. NETD improvement was achieved without compromising detector thermal response or thermal time constant by simultaneous reduction in bolometer heat capacity and thermal conductance. In addition, the DRS unique "umbrella" microbolometer cavities were optically tuned to optimize detector radiation absorption for specific spectral band applications. The 17 micron pixel pitch FPAs are currently being considered for the next generation soldier systems such as thermal weapon sights (TWS), vehicle driver vision enhancers (DVE), digitally fused enhanced night vision goggles (DENVG) and unmanned air vehicle (UAV) surveillance sensors, because of overall thermal imaging system size, weight and power advantages.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Stress analysis of the space telescope focal plane structure joint

    NASA Technical Reports Server (NTRS)

    Foster, W. A., Jr.; Shoemaker, W. L.

    1985-01-01

    Two major efforts were begun concerning the Space Telescope focal plane structure joint. The 3-D solid finite element modeling of the bipod flexure plate was carried out. Conceptual models were developed for the load transfer through the three major bolts to the flexure plate. The flexure plate drawings were reconstructed using DADAM for the purpose of developing a file from which the coordinates of any point on the flexure plate could be determined and also to locate the attachment points of the various components which connect with the flexure plate. For modeling convenience the CADAM drawing of the flexure plate has been divided into several regions which will be subdivided into finite elements using MSGMESH, which is a finite element mesh generator available with MSC/NASTRAN. In addition to the CADAM work on the flexure plate, an effort was also begun to develop computer aided drawings of the peripheral beam which will be used to assist in modeling the connection between it and the flexure plate.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Focal plane mechanical design of the NISP/Euclid instrument

    NASA Astrophysics Data System (ADS)

    Bonnefoi, Anne; Bon, William; Niclas, Mathieu; Solheim, Bjarte G. B.; Torvanger, Oyvind; Schistad, Robert; Foulon, Benjamin; Garcia, José; Vives, Sébastien

    2016-07-01

    Currently in phase C, the Euclid mission selected by ESA in the Cosmic Vision program is dedicated to understand dark energy and dark matter. NISP (standing for Near Infrared Spectro-Photometer) is one of the two instruments of the mission. NISP will combine a photometer and a spectrometer working in the near-IR (0.9-2 microns). Its detection subsystem (called NI-DS) is based on a mosaic of 16 IR detectors cooled down to 90K which are supported by a molybdenum plate. The front-end readout electronics (working at 130K) are supported by another structure in Aluminum. The NI-DS is mounted on the rest of the instrument thanks to a panel in Silicon Carbide (SiC). Finally an optical baffle in Titanium will prevent the rogue light to reach the detectors. On top of the complexity due to the wide range of temperatures and the various materials imposed at the interfaces; the NI-DS has also to incorporate an internal adjustment capability of the position of the focal plane in tip/tilt and focus. This article will present current status of the development of the detection system of NISP.

  17. FOCAL PLANE WAVEFRONT SENSING USING RESIDUAL ADAPTIVE OPTICS SPECKLES

    SciTech Connect

    Codona, Johanan L.; Kenworthy, Matthew

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    DOEpatents

    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.

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

    SciTech Connect

    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.

  1. Detectors and Focal Plane Modules for Weather Satellites

    NASA Technical Reports Server (NTRS)

    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

  2. Detectors and focal plane modules for weather satellites

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    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 μm 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 (λc ~ 5 μm at 98K), MWIR (λc ~ 9 μm at 98K) and LWIRs (λc ~ 15.5 μm 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 μm to 8.6 μm and (iii) a 9.6 μm to 13.3 μm, 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 μm to 0.86 μm channels. The thirteen channels above 1 μm are fabricated in various compositions of Hg1-xCdxTe, and in this particular case using two different detector architectures. The 1.38 μm to 9.61 μm channels are all fabricated in Hg1-xCdxTe grown by Liquid Phase Epitaxy (LPE) using the HDVIP detector architecture. Molecular beam epitaxy (MBE)-grown Hg1-xCdxTe material are used for the LWIR 10.35 μm to 13.3 μm channels fabricated in Double

  3. Validating Phasing and Geometry of Large Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Standley, Shaun P.; Gautier, Thomas N.; Caldwell, Douglas A.; Rabbette, Maura

    2011-01-01

    The Kepler Mission is designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-sized and smaller planets in or near the habitable zone. The Kepler photometer is an array of 42 CCDs (charge-coupled devices) in the focal plane of a 95-cm Schmidt camera onboard the Kepler spacecraft. Each 50x25-mm CCD has 2,200 x 1,024 pixels. The CCDs accumulate photons and are read out every six seconds to prevent saturation. The data is integrated for 30 minutes, and then the pixel data is transferred to onboard storage. The data is subsequently encoded and transmitted to the ground. During End-to-End Information System (EEIS) testing of the Kepler Mission System (KMS), there was a need to verify that the pixels requested by the science team operationally were correctly collected, encoded, compressed, stored, and transmitted by the FS, and subsequently received, decoded, uncompressed, and displayed by the Ground Segment (GS) without the outputs of any CCD modules being flipped, mirrored, or otherwise corrupted during the extensive FS and GS processing. This would normally be done by projecting an image on the focal plane array (FPA), collecting the data in a flight-like way, and making a comparison between the original data and the data reconstructed by the science data system. Projecting a focused image onto the FPA through the telescope would normally involve using a collimator suspended over the telescope opening. There were several problems with this approach: the collimation equipment is elaborate and expensive; as conceived, it could only illuminate a limited section of the FPA (.25 percent) during a given test; the telescope cover would have to be deployed during testing to allow the image to be projected into the telescope; the equipment was bulky and difficult to situate in temperature-controlled environments; and given all the above, test setup, execution, and repeatability were significant concerns. Instead of using this complicated approach of

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Infrared focal plane performance in the South Atlantic anomaly

    NASA Technical Reports Server (NTRS)

    Junga, Frank A.

    1989-01-01

    Proton-induced pulse height distributions (PHD's) in Si:XX detectors were studied analytically and experimentally. In addition, a preliminary design for a flight experiment to characterize the response of Si:XX detectors to the trapped proton environment and verify PHD models was developed. PHD's were computed for two orbit altitudes for a variety of shielding configurations. Most of the proton-induced pulses have amplitudes less that about 3.5 x 10(exp 5) e-h pairs. Shielding has a small effect on the shape of the PHD's. The primary effect of shielding is to reduce the total number of pulses produced. Proton-induced PHD's in a Si:Sb focal plane array bombarded by a unidirectional 67-MeV beam were measured. The maximum pulse height recorded was 6 x 10(exp 5) pairs. The distribution had two peaks: the larger peak corresponded to 3.8 x 10(exp 5) pairs and the smaller peak to 1.2 x 10(exp 5) pairs. The maximum pulse height and the larger peak are within a factor of two of predicted values. The low-energy peak was not expected, but is believed to be an artifact of inefficient charge collection in the detector. The planned flight experiment will be conducted on a Space Shuttle flight. Lockheed's helium extended life dewar (HELD) will be used to provide the required cryogenic environment for the detector. Two bulk Si:Sb arrays and two Si:As impurity band conduction arrays will be tested. The tests will be conducted while the Space Shuttle passes through the South Atlantic Anomaly. PHD's will be recorded and responsivity changes tracked. This experiment will provide a new database on proton-induced PHD's, compare two infrared detector technologies in a space environment, and provide the data necessary to validate PHD modeling.

  6. Infrared focal plane performance in the South Atlantic anomaly

    NASA Astrophysics Data System (ADS)

    Junga, Frank A.

    1989-09-01

    Proton-induced pulse height distributions (PHD's) in Si:XX detectors were studied analytically and experimentally. In addition, a preliminary design for a flight experiment to characterize the response of Si:XX detectors to the trapped proton environment and verify PHD models was developed. PHD's were computed for two orbit altitudes for a variety of shielding configurations. Most of the proton-induced pulses have amplitudes less that about 3.5 x 10(exp 5) e-h pairs. Shielding has a small effect on the shape of the PHD's. The primary effect of shielding is to reduce the total number of pulses produced. Proton-induced PHD's in a Si:Sb focal plane array bombarded by a unidirectional 67-MeV beam were measured. The maximum pulse height recorded was 6 x 10(exp 5) pairs. The distribution had two peaks: the larger peak corresponded to 3.8 x 10(exp 5) pairs and the smaller peak to 1.2 x 10(exp 5) pairs. The maximum pulse height and the larger peak are within a factor of two of predicted values. The low-energy peak was not expected, but is believed to be an artifact of inefficient charge collection in the detector. The planned flight experiment will be conducted on a Space Shuttle flight. Lockheed's helium extended life dewar (HELD) will be used to provide the required cryogenic environment for the detector. Two bulk Si:Sb arrays and two Si:As impurity band conduction arrays will be tested. The tests will be conducted while the Space Shuttle passes through the South Atlantic Anomaly. PHD's will be recorded and responsivity changes tracked. This experiment will provide a new database on proton-induced PHD's, compare two infrared detector technologies in a space environment, and provide the data necessary to validate PHD modeling.

  7. Design of diffractive microlens array integration with focal plane arrays

    NASA Astrophysics Data System (ADS)

    Chen, Sihai; Yi, Xinjian; Li, Yi; He, Miao; Chen, Sixiang; Kong, Lingbin

    2000-10-01

    The IR spectrum from 3 to 5micrometers has numerous applications in both military and civil industries. High performance at high operating temperature is often important in these applications. Conventional Focal Plane Arrays (FPAs) without integration with concentrator such as microlens have poor sensitivity and low signal-to-noise ratio because of their lower fill factor. The binary optics microlens arrays reported in this paper are designed for integration with FPAs. Thus, the FPAs' fill factor, sensitivity, and signal- to-noise ratio can be improved while retaining a given image resolution and optical collection area. In the paper, we discussed the 256(Horizontal)x290(Vertical) microlens arrays designed for a center wavelength of 4micrometers , with 50micrometers (Horizontalx33micrometers (Vertical) quadrate pixel dimension and a speed (F number) of F/1.96. PtSi FPAs were fabricated on the front side of a 400-micrometers -thick Si substrate. The designed diffractive microlens arrays will be etched on the back side of the same wafer in a register fashion and it will be reported in other paper. Considering the diffraction efficiency, 8-phase-level approximation is enough. For the diffraction efficiency of 8-phase-level diffractive microlens reaches 95%. The process only need three mask-level, so we designed and fabricated three masks with the same dimension 4'x4'. Also, a set of fine verniers was designed and fabricated on each mask to allow accurate alignment during the fabrication process. Through a computer simulation, the microlens arrays are nearly diffraction limited, with the diffraction efficiency of 93%, a bit lower than the theoretical value of 95%. Introduction of microlens arrays has the ability to increase the FPAs' fill factor to 100%, while it is only about 21.6% without microlens. To our knowledge, this is the first trial of integration large area microlens arrays with FPAs at home.

  8. Focal-plane electric field sensing with pupil-plane holograms

    NASA Astrophysics Data System (ADS)

    Por, Emiel H.; Keller, Christoph U.

    2016-07-01

    The direct detection and spectral characterization of exoplanets requires a coronagraph to suppress the diffracted star light. Amplitude and phase aberrations in the optical train fill the dark zone of the coronagraph with quasi-static speckles that limit the achievable contrast. Focal-plane electric field sensing, such as phase diversity introduced by a deformable mirror (DM), is a powerful tool to minimize this residual star light. The residual electric field can be estimated by sequentially applying phase probes on the DM to inject star light with a well-known amplitude and phase into the dark zone and analyzing the resulting intensity images. The DM can then be used to add light with the same amplitude but opposite phase to destructively interfere with this residual star light. Using a static phase-only pupil-plane element we create holographic copies of the point spread function (PSF), each superimposed with a certain pupil-plane phase probe. We therefore obtain all intensity images simultaneously while still retaining a central, unaltered science PSF. The electric field sensing method only makes use of the holographic copies, allowing for correction of the residual electric field while retaining the central PSF for uninterrupted science data collection. In this paper we demonstrate the feasibility of this method with numerical simulations.

  9. Experimental characterization, evaluation, and diagnosis of advanced hybrid infrared focal plane array electro-optical performance

    NASA Astrophysics Data System (ADS)

    Lomheim, Terrence S.; Schumann, Lee W.; Kohn, Stanley E.

    1998-07-01

    High performance scanning time-delay-and-integration and staring hybrid focal plane devices with very large formats, small pixel sizes, formidable frame and line rates, on-chip digital programmability, and high dynamic ranges, are being developed for a myriad of defense, civil, and commercial applications that span the spectral range from shortwave infrared (SWIR) to longwave infrared (LWIR). An essential part in the development of such new advanced hybrid infrared focal planes is empirical validation of their electro-optical (EO) performance. Many high-reliability, high-performance applications demand stringent and near flawless EO performance over a wide variety of operating conditions and environments. Verification of focal plane performance compliance over this wide range of parametric conditions requires the development and use of accurate, flexible, and statistically complete test methods and associated equipment. In this paper we review typical focal plane requirements, the ensuing measurement requirements (quantity, accuracy, repeatability, etc.), test methodologies, test equipment requirements, electronics and computer-based data acquisition requirements, statistical data analysis and display requirements, and associated issues. We also discuss special test requirements for verifying the performance of panchromatic thermal and multispectral imaging focal planes where characterization of dynamic modulation transfer function (MTF), and point-image response and optical overload is generally required. We briefly overview focal plane radiation testing. We conclude with a discussion of the technical challenges of characterizing future advanced hybrid focal plane testing where it is anticipated that analog-to- digital conversion will be included directly on focal plane devices, thus creating the scenario of 'photons-in-to-bits- out' within the focal plane itself.

  10. Detectors and focal plane modules for weather instruments

    NASA Astrophysics Data System (ADS)

    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.

  11. Detectors and Focal Plane Modules for Weather Instruments

    NASA Technical Reports Server (NTRS)

    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.

  12. Advances in Focal Plane Wavefront Estimation for Directly Imaging Exoplanets

    NASA Astrophysics Data System (ADS)

    Eldorado Riggs, A. J.; Kasdin, N. Jeremy; Groff, Tyler Dean

    2015-01-01

    To image cold exoplanets directly in visible light, an instrument on a telescope needs to suppress starlight by about 9 orders of magnitude at small separations from the star. A coronagraph changes the point spread function to create regions of high contrast where exoplanets or disks can be seen. Aberrations on the optics degrade the contrast by several orders of magnitude, so all high-contrast imaging systems incorporate one or more deformable mirrors (DMs) to recover regions of high contrast. With a coronagraphic instrument planned for the WFIRST-AFTA space telescope, there is a pressing need for faster, more robust estimation and control schemes for the DMs. Non-common path aberrations limit conventional phase conjugation schemes to medium star-to-planet contrast ratios of about 1e-6. High-contrast imaging requires estimation and control of both phase and amplitude in the same beam path as the science camera. Field estimation is a challenge since only intensity is measured; the most common approach, including that planned for WFIRST-AFTA, is to use DMs to create diversity, via pairs of small probe shapes, thereby allowing disambiguation of the electric field. Most implementations of DM Diversity require at least five images per electric field estimate and require narrowband measurements. This paper describes our new estimation algorithms that improve the speed (by using fewer images) and bandwidth of focal plane wavefront estimation. For narrowband estimation, we are testing nonlinear, recursive algorithms such as an iterative extended Kalman filter (IEKF) to use three images each iteration and build better, more robust estimates. We are also exploring the use of broadband estimation without the need for narrowband sub-filters and measurements. Here we present simulations of these algorithms with realistic noise and small signals to show how they might perform for WFIRST-AFTA. Once validated in simulations, we will test these algorithms experimentally in

  13. Focal-plane irradiance tailoring using the concept of Woofer-Tweeter deformable mirrors.

    PubMed

    Feng, Zexin; Huang, Lei; Gong, Mali

    2014-04-21

    Deformable mirror (DM) is a common-used active freeform optical element. We introduce the concept of Woofer-Tweeter DM system for controlling focal-plane irradiance profiles. We firstly determine a freeform reflective surface for transforming a given incident laser beam into the desired focal-plane irradiance distribution by numerically solving a standard Monge-Ampère equation. Then, we use a low-bandwidth Woofer DM to approximate the required freeform reflective surface and a high-bandwidth Tweeter DM to compensate the residual error. Simulation results show that, compared with single DMs, the Woofer-Tweeter DM system brings the best focal-plane irradiance performances.

  14. LWIR scene simulator developed for end-to-end performance evaluation of focal planes

    NASA Technical Reports Server (NTRS)

    Thompson, Niels A.; Bowser, William M.; Song, Sung H.; Skiff, Laura T.; Powell, William W.; Romero, Charles

    1992-01-01

    The development of a long-wave infrared optical simulator facilitates evaluation of the end-to-end performance of long wavelength infrared (LWIR) focal plane arrays (FPAs) in a system-like environment. This simulator provides selectable structured scene inputs to a focal plane module or array. Background irradiances as low as 10 exp 10 photons/sq cm s are achievable when the simulator is cooled with liquid helium. The optical simulator can generate single or multiple targets of controllable intensities, and uniform or structured background irradiances. The infrared scenes can be viewed in a stationary mode or dynamically scanned across the focal plane.

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

    NASA Technical Reports Server (NTRS)

    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

  16. 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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  19. Kinoform phase plates for focal plane irradiance profile control

    SciTech Connect

    Dixit, S.N.; Lawson, J.K.; Manes, K.R.; Powell, H.T. ); Nugent, K.A. )

    1994-03-15

    A versatile, rapidly convergent, iterative algorithm is presented for the construction of kinoform phase plates for tailoring the far-field intensity distribution of laser beams. The method consists of repeated Fourier transforming between the near-field and the far-field planes with constraints imposed in each plane. For application to inertial confinement fusion, the converged far-field pattern contains more than 95% of the incident energy inside a desired region and is relatively insensitive to beam aberrations.

  20. Correlation between Focal Nodular Low Signal Changes in Hoffa's Fat Pad Adjacent to Anterior Femoral Cartilage and Focal Cartilage Defect Underlying This Region and Its Possible Implication

    PubMed Central

    Ng, Wuey Min

    2016-01-01

    Purpose. This study investigates the association between focal nodular mass with low signal in Hoffa's fat pad adjacent to anterior femoral cartilage of the knee (FNMHF) and focal cartilage abnormality in this region. Method. The magnetic resonance fast imaging employing steady-state acquisition sequence (MR FIESTA) sagittal and axial images of the B1 and C1 region (described later) of 148 patients were independently evaluated by two reviewers and categorized into four categories: normal, FNMHF with underlying focal cartilage abnormality, FNMHF with normal cartilage, and cartilage abnormality with no FNMHF. Results. There was a significant association (p = 0.00) between FNMHF and immediate adjacent focal cartilage abnormality with high interobserver agreement. The absence of focal nodular lesions next to the anterior femoral cartilage has a very high negative predictive value for chondral injury (97.8%). Synovial biopsy of focal nodular lesion done during arthroscopy revealed some fibrocollagenous tissue and no inflammatory cells. Conclusion. We postulate that the FNMHF adjacent to the cartilage defects is a form of normal healing response to the cartilage damage. One patient with FHMHF and underlying cartilage abnormality was rescanned six months later. In this patient, the FNMHF disappeared and normal cartilage was observed in the adjacent region which may support this theory. PMID:27213085

  1. Materials, devices, techniques, and applications for Z-plane focal plane array technology II; Proceedings of the Meeting, San Diego, CA, July 12, 13, 1990

    NASA Astrophysics Data System (ADS)

    Carson, John C.

    1990-11-01

    Various papers on materials, devices, techniques, and applications for X-plane focal plane array technology are presented. Individual topics addressed include: application of Z-plane technology to the remote sensing of the earth from GEO, applications of smart neuromorphic focal planes, image-processing of Z-plane technology, neural network Z-plane implementation with very high interconnection rates, using a small IR surveillance satellite for tactical applications, establishing requirements for homing applications, Z-plane technology. Also discussed are: on-array spike suppression signal processing, algorithms for on-focal-plane gamma circumvention and time-delay integration, current HYMOSS Z-technology, packaging of electrons for on- and off-FPA signal processing, space/performance qualification of tape automated bonded devices, automation in tape automated bonding, high-speed/high-volume radiometric testing of Z-technology focal planes, 128-layer HYMOSS-module fabrication issues, automation of IRFPA production processes.

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

    NASA Technical Reports Server (NTRS)

    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.

  3. Focal-plane detector system for the KATRIN experiment

    DOE PAGES

    Amsbaugh, J. F.; Barrett, J.; Beglarian, A.; ...

    2015-01-09

    Here, the local plane detector system for the KArlsiuhe 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.

  4. Low power, highly linear output buffer. [for infrared focal plane arrays

    NASA Technical Reports Server (NTRS)

    Foley, D.; Butler, N.; Stobie, J.

    1992-01-01

    A class AB CMOS output buffer has been designed for use on an IR focal plane array. Given the requirements for power dissipation and load capacitance a class A output, such as a source follower, would be unsuitable. The approach taken uses a class AB amplifier configured as a charge integrator. Thus it converts a charge packet in the focal plane multiplexer to a voltage which is then the output of the focal plane. With a quiescent current of 18 micro-a and a load capacitance of 100 pf, the amplifier has an open loop unity gain bandwidth of 900 khz. Integral nonlinearity is better than .03 percent over 5.5 volts when run with VDD-VSS = 6v.

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

    NASA Technical Reports Server (NTRS)

    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.

  6. An Integrated Optimal Estimation Approach to Spitzer Space Telescope Focal Plane Survey

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    This paper discusses an accurate and efficient method for focal plane survey that was used for the Spitzer Space Telescope. The approach is based on using a high-order 37-state Instrument Pointing Frame (IPF) Kalman filter that combines both engineering parameters and science parameters into a single filter formulation. In this approach, engineering parameters such as pointing alignments, thermomechanical drift and gyro drifts are estimated along with science parameters such as plate scales and optical distortions. This integrated approach has many advantages compared to estimating the engineering and science parameters separately. The resulting focal plane survey approach is applicable to a diverse range of science instruments such as imaging cameras, spectroscopy slits, and scanning-type arrays alike. The paper will summarize results from applying the IPF Kalman Filter to calibrating the Spitzer Space Telescope focal plane, containing the MIPS, IRAC, and the IRS science Instrument arrays.

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

    SciTech Connect

    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.

  8. Evaluation of calibration methods for visible-spectrum division-of-focal-plane polarimeters

    NASA Astrophysics Data System (ADS)

    Powell, S. B.; Gruev, Viktor

    2013-09-01

    Polarization imaging sensors using the division-of-focal-plane paradigm have recently emerged on the market. These sensors, due to their compact design, are ideal for field work. One of the major drawbacks in these sensors is the spatial variation of the optical response of individual pixels across the imaging array. These spatial variations are due to variations in the nanowires of the pixelated polarization filters. In this paper, we describe and compare two methods for calibrating a division of focal plane sensors. We present theoretical and experimental data for these calibration methods.

  9. Method of fabricating multiwavelength infrared focal plane array detector

    NASA Technical Reports Server (NTRS)

    Forrest, Stephen R. (Inventor); Olsen, Gregory H. (Inventor); Kim, Dong-Su (Inventor); Lange, Michael J. (Inventor)

    1996-01-01

    A multiwavelength local plane array infrared detector is included on a common substrate having formed on its top face a plurality of In.sub.x Ga.sub.1-x As (x.ltoreq.0.53) absorption layers, between each pair of which a plurality of InAs.sub.y P.sub.1-y (y.ltoreq.1) buffer layers are formed having substantially increasing lattice parameters, respectively, relative to said substrate, for preventing lattice mismatch dislocations from propagating through successive ones of the absorption layers of decreasing bandgap relative to said substrate, whereby a plurality of detectors for detecting different wavelengths of light for a given pixel are provided by removing material above given areas of successive ones of the absorption layers, which areas are doped to form a pn junction with the surrounding unexposed portions of associated absorption layers, respectively, with metal contacts being formed on a portion of each of the exposed areas, and on the bottom of the substrate for facilitating electrical connections thereto.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  12. High-precision method for determining the position of laser beam focal plane

    SciTech Connect

    Malashko, Ya I; Kleimenov, A N; Potemkin, I B; Khabibulin, V M

    2013-12-31

    The method of wavefront doubled-frequency spherical modulation for determining the laser beam waist position has been simulated and experimentally studied. The error in determining the focal plane position is less than 10{sup -5} D. The amplitude of the control doubled-frequency electric signal is experimentally found to correspond to 12% of the total radiation power. (laser beams)

  13. Development and Testing of an Innovative Two-Arm Focal-Plane Thermal Strap (TAFTS)

    NASA Technical Reports Server (NTRS)

    Urquiza, E.; Vasquez, C.; Rodriguez, J.; Van Gorp, B.

    2011-01-01

    Maintaining temperature stability in optical focal planes comes with the intrinsic challenge of creating a pathway that is both extremely flexible mechanically and highly conductive thermally. The task is further complicated because science-caliber optical focal planes are extremely delicate, yet their mechanical resiliency is rarely tested and documented. The mechanical engineer tasked with the thermo-mechanical design must then create a highly conductive thermal link that minimizes the tensile and shear stresses transmitted to the focal plane without design parameters on an acceptable stiffness. This paper will describe the development and testing of the thermal link developed for the Portable Remote Imaging Spectrometer (PRISM) instrument. It will provide experimentally determined mechanical stiffness plots in the three axes of interest. Analytical and experimental thermal conductance results for the two-arm focal-plane thermal strap (TAFTS), from cryogenic to room temperatures, are also presented. The paper also briefly describes some elements of the fabrication process followed in developing a novel design solution, which provides high conductance and symmetrical mechanical loading, while providing enhanced flexibility in all three degrees of freedom.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Sound propagation through a discretely inhomogeneous thermoelastic plane layer adjacent to heat-conducting liquids

    NASA Astrophysics Data System (ADS)

    Tolokonnikov, L. A.; Larin, N. V.

    2017-01-01

    An analytical solution of the problem of the propagation of a plane sound wave through a discretely inhomogeneous thermoelastic layer adjacent to inviscid heat-conducting liquids is obtained. Results of calculations of the dependences of the transmission coefficient on the wave incidence angle and frequency for discretely inhomogeneous and continuously inhomogeneous thermoelastic layers are given. It is shown that a thermoelastic layer with continuously inhomogeneous thickness can be simulated using a system of homogeneous thermoelastic layers.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Uncooled bolometer-type Terahertz focal plane array and camera for real-time imaging

    NASA Astrophysics Data System (ADS)

    Oda, Naoki

    2010-08-01

    Real-time Terahertz (THz) imaging technologies which make use of uncooled bolometer-type infrared focal plane arrays (FPAs) and quantum cascade lasers (QCLs) will be reviewed. A description of how THz focal plane array and THz imagers have been developed on the basis of infrared technologies, especially the improvement in both THz sensitivity of bolometer-type FPA and THz transmittance of materials for lens and vacuum package window will be given. Characteristics of 320×240 THz-FPA, such as relation of noise equivalent power (NEP) to wavelength and real-time THz imageries will be presented. One of the imageries indicates that THz technology is promising for label-free detection of reaction of small molecules with proteins.

  18. Solar-Driven Background Intensity Variations in a Focal Plane Array

    SciTech Connect

    Eyer, H.H.; Guillen, J.L.L.; Vittitoe, C.N.

    1998-12-03

    Portions of a series of end-of-life tests are described for a Sandia National Li~boratories- designed space-based sensor that utilizes a mercury-cadmium-telluride focal plane array. Variations in background intensity are consistent with the hypothesis that seasonal variations in solar position cause changes in the pattern of shadows falling across the compartment containing the optical elements, filter-band components, and focal plane array. When the sensor compartment is most fully illuminated by the sun, background intensities are large and their standard deviations tend to be large. During the winter season, when the compartment is most fully shadowed by surrounding structure, backgrounci intensities are small and standard deviations tend to be small. Details in the surrounding structure are speculated to produce transient shadows that complicate background intensifies as a function of time or of sensor position in orbit.

  19. Status of on-focal-plane signal processing utilizing 3D silicon technology

    NASA Astrophysics Data System (ADS)

    Carson, John C.

    1994-03-01

    3D silicon technology has been under development since 1980, primarily aimed at on-focal- plane signal processing to solve a variety of military sensor systems problems. The thrust has been to bring more and more parallel analog and digital processing into the closest possible proximity to the detector array. At this time on-focal-plane functionality includes preamplification, spatial and temporal matched filtering, nonuniformity correction, neural networks, analog-digital conversion, digital logic, and digital memory. Historically, a custom- built specialty technology constrained by cost in its applicability, 3D silicon has undergone a dual-use conversion to include high-volume, low-cost commercial computer electronics. 3D silicon is on the way to becoming the lowest-cost-per-gate technology available and, because of this, sensor system design and performance will be revolutionized.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Real Time Imaging Analysis Using a Terahertz Quantum Cascade Laser and a Microbolometer Focal Plane Array

    DTIC Science & Technology

    2008-12-01

    sensing area, assuming that the device remains approximately in thermodynamic equilibrium, the heat balance equation can be expressed as o d TP G T C...11. Modulated radiation incident on focal plane array. .........................................17 Figure 12. Temperature change in a pixel for P0...for b) 4.3 and c) 4.9 THz windows. HITRAN (solid line) and FTIR results (dashed line). Lasing spectra of QCL’s are depicted with dashed vertical

  2. Short wavelength HgCdTe staring focal plane for low background astronomy applications

    NASA Technical Reports Server (NTRS)

    Hall, D.; Stobie, J.; Hartle, N.; Lacroix, D.; Maschhoff, K.

    1989-01-01

    The design of a 128x128 staring short wave infrared (SWIR) HgCdTe focal plane incorporating charge integrating transimpedance input preamplifiers is presented. The preamplifiers improve device linearity and uniformity, and provide signal gain ahead of the miltiplexer and readout circuitry. Detector's with cutoff wavelength of 2.5 microns and operated at 80 K have demonstrated impedances in excess of 10(exp 16) ohms with 60 percent quantum efficiency. Focal plane performance using a smaller format device is presented which demonstrates the potential of this approach. Although the design is capable of achieving less than 30 rms electrons with todays technology, initial small format devices demonstrated a read noise of 100 rms electrons and were limited by the atypical high noise performance of the silicon process run. Luminescence from the active silicon circuitry in the multiplexer limits the minimum detector current to a few hundred electrons per second. Approaches to eliminate this excessive source of current is presented which should allow the focal plane to achieve detector background limited performance.

  3. Focal plane resolution and overlapped array time delay and integrate imaging

    NASA Astrophysics Data System (ADS)

    Grycewicz, Thomas J.; Cota, Stephen A.; Lomheim, Terrence S.; Kalman, Linda S.

    2010-06-01

    In this paper we model sub-pixel image registration for a generic earth-observing satellite system with a focal plane using two offset time delay and integrate (TDI) arrays in the focal plane to improve the achievable ground resolution over the resolution achievable with a single array. The modeling process starts with a high-resolution image as ground truth. The Parameterized Image Chain Analysis & Simulation Software (PICASSO) modeling tool is used to degrade the images to match the optical transfer function, sampling, and noise characteristics of the target system. The model outputs a pair of images with a separation close to the nominal half-pixel separation between the overlapped arrays. A registration estimation algorithm is used to measure the offset for image reconstruction. The two images are aligned and summed on a grid with twice the capture resolution. We compare the resolution in images between the inputs before overlap, the reconstructed image, and a simulation for the image which would have been captured on a focal plane with twice the resolution. We find the performance to always be better than the lower resolution baseline, and to approach the performance of the high-resolution array in the ideal case. We show that the overlapped array imager significantly outperforms both the conventional high- and low-resolution imagers in conditions with high image smear.

  4. MIXS on BepiColombo and its DEPFET based focal plane instrumentation

    NASA Astrophysics Data System (ADS)

    Treis, J.; Andricek, L.; Aschauer, F.; Heinzinger, K.; Herrmann, S.; Hilchenbach, M.; Lauf, T.; Lechner, P.; Lutz, G.; Majewski, P.; Porro, M.; Richter, R. H.; Schaller, G.; Schnecke, M.; Schopper, F.; Soltau, H.; Stefanescu, A.; Strüder, L.; de Vita, G.

    2010-12-01

    Focal plane instrumentation based on DEPFET Macropixel devices, being a combination of the Detector-Amplifier structure DEPFET with a silicon drift chamber (SDD), has been proposed for the MIXS (Mercury Imaging X-ray Spectrometer) instrument on ESA's Mercury exploration mission BepiColombo. MIXS images X-ray fluorescent radiation from the Mercury surface with a lightweight X-ray mirror system on the focal plane detector to measure the spatially resolved element abundance in Mercury's crust. The sensor needs to have an energy resolution better than 200 eV FWHM at 1 keV and is required to cover an energy range from 0.5 to 10 keV, for a pixel size of 300×300μm2. Main challenges for the instrument are radiation damage and the difficult thermal environment in the mercury orbit. The production of the first batch of flight devices has been finished at the MPI semiconductor laboratory. Prototype modules have been assembled to verify the electrical properties of the devices; selected results are presented here. The prototype devices, Macropixel prototypes for the SIMBOL-X focal plane, are electrically fully compatible, but have a pixel size of 0.5×0.5 mm2. Excellent homogeneity and near Fano-limited energy resolution at high readout speeds have been observed on these devices.

  5. Accuracy and uncertainty in random speckle modulation transfer function measurement of infrared focal plane arrays

    NASA Astrophysics Data System (ADS)

    Barnard, Kenneth J.; Jacobs, Eddie L.; Plummer, Philip J.

    2016-12-01

    This paper expands upon a previously reported random speckle technique for measuring the modulation transfer function of midwave infrared focal plane arrays by considering a number of factors that impact the accuracy of the estimated modulation transfer function. These factors arise from assumptions in the theoretical derivation and bias in the estimation procedure. Each factor is examined and guidelines are determined to maintain accuracy within 2% of the true value. The uncertainty of the measurement is found by applying a one-factor ANOVA analysis and confidence intervals are established for the results. The small magnitude of the confidence intervals indicates a very robust technique capable of distinguishing differences in modulation transfer function among focal plane arrays on the order of a few percent. This analysis directly indicates the high quality of the random speckle modulation transfer function measurement technique. The methodology is applied to a focal plane array and results are presented that emphasize the need for generating independent random speckle realizations to accurately assess measured values.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Focal plane actuation for the development of a high resolution suborbital telescope

    NASA Astrophysics Data System (ADS)

    Duke Miller, Alex; Scowen, Paul A.; Veach, Todd

    2016-01-01

    We present a hexapod stabilized focal plane as the key instrument for a proposed suborbital balloon mission. Balloon gondolas currently achieve 1-2 arcsecond pointing error, but cannot correct for unavoidable jitter movements (~50μm at 20hz) caused by wind rushing over balloon surfaces, thermal variations, cryocoolers, and reaction wheels. The jitter causes image blur during exposures and is the limiting resolution of the system. To solve this, the hexapod system actuates the focal plane to counteract the jitter through real-time closed loop feedback from star-trackers. Removal of this final jitter term decreases pointing error by an order of magnitude and allows for true diffraction-limited observation. This boost in resolution will allow for Hubble-quality imaging for a fraction of the cost. 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. The design also thermally isolates the hexapod from the cryogenic focal plane enabling the use of well-established non-cryogenic hexapod technology. High-resolution time domain multispectral imaging of the gas giant outer planets, 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 data. On an Antarctic ~100-day Long-Duration-Balloon mission the continued high-resolution imaging of gas giant storm systems would provide cloud formation and evolution data second to only a Flagship orbiter.

  9. InstantScope: a low-cost whole slide imaging system with instant focal plane detection.

    PubMed

    Guo, Kaikai; Liao, Jun; Bian, Zichao; Heng, Xin; Zheng, Guoan

    2015-09-01

    We report the development of a high-throughput whole slide imaging (WSI) system by adapting a cost-effective optomechanical add-on kit to existing microscopes. Inspired by the phase detection concept in professional photography, we attached two pinhole-modulated cameras at the eyepiece ports for instant focal plane detection. By adjusting the positions of the pinholes, we can effectively change the view angle for the sample, and as such, we can use the translation shift of the two pinhole-modulated images to identify the optimal focal position. By using a small pinhole size, the focal-plane-detection range is on the order of millimeter, orders of magnitude longer than the objective's depth of field. We also show that, by analyzing the phase correlation of the pinhole-modulated images, we can determine whether the sample contains one thin section, folded sections, or multiple layers separated by certain distances - an important piece of information prior to a detailed z scan. In order to achieve system automation, we deployed a low-cost programmable robotic arm to perform sample loading and $14 stepper motors to drive the microscope stage to perform x-y scanning. Using a 20X objective lens, we can acquire a 2 gigapixel image with 14 mm by 8 mm field of view in 90 seconds. The reported platform may find applications in biomedical research, telemedicine, and digital pathology. It may also provide new insights for the development of high-content screening instruments.

  10. Curved Focal-Plane Arrays Using Back-Illuminated High-Purity Photodetectors

    NASA Technical Reports Server (NTRS)

    Nikzad, Shouleh; Hoenk, Michael E.

    2003-01-01

    Curved-focal-plane arrays of back-illuminated silicon-based photodetectors are being developed. The basic idea is to improve the performance of an imaging instrument and simplify the optics needed to obtain a given level of performance by making an image sensor (e.g., a photographic film or an array of photodetectors) conform to a curved focal surface, instead of following the customary practice of designing the optics to project an image onto a flat focal surface. Eyes are natural examples of optical systems that have curved focal surfaces on which image sensors (retinas) are located. One prior approach to implementation of this concept involves the use of curved-input-surface microchannel plates as arrays of photodetectors. In comparison with microchannel plates, these curved-focal-plane arrays would weigh less, operate at much lower voltages, and consume less power. It should also be possible to fabricate the proposed devices at lower cost. It would be possible to fabricate an array of photodetectors and readout circuitry in the form of a very-large-scale integrated (VLSI) circuit on a curved focal surface, but it would be difficult and expensive to do so. In a simple and inexpensive alternate approach, a device (see figure) would have (1) a curved back surface, onto which light would be focused; and (2) a flat front surface, on which VLSI circuitry would be fabricated by techniques that are well established for flat surfaces. The device would be made from ultrapure silicon, in which it is possible to form high-resistivity, thick photodetectors that are fully depleted through their thicknesses. (As used here, "thick means having a thickness between a fraction of a millimeter and a few millimeters.) The back surface would be polished to the curvature of the focal surface of the intended application. To enable the collection of charge carriers excited by photons near the back surface or in the bulk of the device, it would be necessary to form a transparent or

  11. A Design of Focal-plane Compensation of Aviation Imaging Equipment Based on MS5534C

    NASA Astrophysics Data System (ADS)

    Lina, Zheng; Xue, Leng; Jiufei, Zhou; Yong, He; Jinbao, Fu

    This paper proposes an auto-compensation method for defocusing distance caused by temperature and pressure in aviation imaging equipment. As the host computer, the TMS320F2812 is the core controller and the digital pressure sensor MS5534C from Intersema Company is used as slave computer. The controller acquires the output of the temperature and the pressure from the sensor through MCBSP interface. By the change of temperature and pressure which results in defocusing distance, the software is adopted to compensate the defocusing distance and thereby keeps the stabilization of focal plane in aviation imaging equipment. The design proposal and the software flow is shown in the paper, furthermore the new system has simple interface, small size and real-time function. With many flight tests, the defocusing distance after the compensation of temperature and pressure is far less than the half focal depth of the optical system and it is fully satisfied with the requirements of imaging.

  12. Hemispherical infrared focal plane arrays: a new design parameter for the instruments

    NASA Astrophysics Data System (ADS)

    Fendler, M.; Dumas, D.; Chemla, F.; Cohen, M.; Laporte, P.; Tekaya, K.; Le Coarer, E.; Primot, J.; Ribot, H.

    2012-07-01

    In ground based astronomy, mainly all designs of sky survey telescopes are limited by the requirement that the detecting surface is flat whereas the focal surface is curved. Two kinds of solution have been investigated up to now. The first one consists in adding optical systems to flatten the image surface; however this solution complicates the design and increases the system size. Somehow, this solution increases, in the same time, the weight and price of the instrument. The second solution consists in curving artificially the focal surface by using a mosaic of several detectors, which are positioned in a spherical shape. However, this attempt is dedicated to low curvature and is limited by the technical difficulty to control the detectors alignment and tilt between each others. Today we would like to propose an ideal solution which is to curve the focal plane array in a spherical shape, thanks to our monolithic process developed at CEA-LETI based on thinned silicon substrates which allows a 100% optical fill factor. Two infrared uncooled cameras have been performed, using 320 x 256 pixels and 25 μm pitch micro-bolometer arrays curved at a bending radius of 80 mm. These two micro-cameras illustrate the optical system simplification and miniaturization involved by curved focal plane arrays. Moreover, the advantages of curved detectors on the optical performances (Point Spreading Function), as well as on volume and cost savings have been highlighted by the simulation of the opto-mechanical architecture of the spectrometer OptiMOS-EVE for the European Extremely Large Telescope (E-ELT).

  13. Design and performance of the eROSITA focal plane instrumentation

    NASA Astrophysics Data System (ADS)

    Meidinger, Norbert; Andritschke, Robert; Aschauer, Florian; Elbs, Johannes; Eraerds, Tanja; Granato, Stefanie; Hälker, Olaf; Hartner, Gisela; Mießner, Danilo; Pietschner, Daniel; Predehl, Peter; Reiffers, Jonas; Strüder, Lothar; von Kienlin, Andreas; Walther, Sabine

    2012-07-01

    We developed and tested X-ray PNCCD focal plane detectors for the eROSITA (extended ROentgen Survey with an Imaging Telescope Array) space telescope. General scientific goal of the eROSITA project is the exploration of the X-ray universe in the energy band from about 0.2 keV up to 10 keV with excellent energy, time, and spatial resolution in combination with large effective telescope areas. The observational program divides into an all-sky survey and pointed observations. The mission duration is scheduled for 7.5 years. The German instrument will be launched in near future to the Lagrange point L2 on the Russian satellite SRG. The detection of single X-ray photons with precise information about their energy, angle of incidence and time is accomplished for eROSITA by an array of seven identical and independent PNCCD cameras. Each camera is assigned to a dedicated mirror system of Wolter-I type. The key component of the camera is a 5 cm • 3 cm large, back-illuminated, 450 μm thick and fully depleted frame store PNCCD chip. This chip is a further development of the sensor type that is in operation as focal plane detector on the XMMNewton satellite since launch in 1999 to date. Development and production of the CCDs for the eROSITA project were performed by the MPI Halbleiterlabor, as already in the past for the XMM-Newton project. According to the status of the project, a complete design of the seven flight cameras including the camera electronics and the filter wheel has been developed. Various functional and performance tests have been accomplished for a detailed characterization of the eROSITA camera system. We focus here especially on the focal plane detector design and the performance of the detectors, which are essential for the success of the X-ray astronomy space project.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. The effect of averaging adjacent planes for artifact reduction in matrix inversion tomosynthesis

    SciTech Connect

    Godfrey, Devon J.; Page McAdams, H.; Dobbins, James T. III

    2013-02-15

    Purpose: Matrix inversion tomosynthesis (MITS) uses linear systems theory and knowledge of the imaging geometry to remove tomographic blur that is present in conventional backprojection tomosynthesis reconstructions, leaving in-plane detail rendered clearly. The use of partial-pixel interpolation during the backprojection process introduces imprecision in the MITS modeling of tomographic blur, and creates low-contrast artifacts in some MITS planes. This paper examines the use of MITS slabs, created by averaging several adjacent MITS planes, as a method for suppressing partial-pixel artifacts. Methods: Human chest tomosynthesis projection data, acquired as part of an IRB-approved pilot study, were used to generate MITS planes, three-plane MITS slabs (MITSa3), five-plane MITS slabs (MITSa5), and seven-plane MITS slabs (MITSa7). These were qualitatively examined for partial-pixel artifacts and the visibility of normal and abnormal anatomy. Additionally, small (5 mm) subtle pulmonary nodules were simulated and digitally superimposed upon human chest tomosynthesis projection images, and their visibility was qualitatively assessed in the different reconstruction techniques. Simulated images of a thin wire were used to generate modulation transfer function (MTF) and slice-sensitivity profile curves for the different MITS and MITS slab techniques, and these were examined for indications of partial-pixel artifacts and frequency response uniformity. Finally, mean-subtracted, exposure-normalized noise power spectra (ENNPS) estimates were computed and compared for MITS and MITS slab reconstructions, generated from 10 sets of tomosynthesis projection data of an acrylic slab. The simulated in-plane MTF response of each technique was also combined with the square root of the ENNPS estimate to yield stochastic signal-to-noise ratio (SNR) information about the different reconstruction techniques. Results: For scan angles of 20 Degree-Sign and 5 mm plane separation, seven MITS

  16. Three-Dimensional Integration Technology for Advanced Focal Planes and Integrated Circuits

    SciTech Connect

    Keast, Craig

    2007-02-28

    Over the last five years MIT Lincoln Laboratory (MIT-LL) has developed a three-dimensional (3D) circuit integration technology that exploits the advantages of silicon-on-insulator (SOI) technology to enable wafer-level stacking and micrometer-scale electrical interconnection of fully fabricated circuit wafers. Advanced focal plane arrays have been the first applications to exploit the benefits of this 3D integration technology because the massively parallel information flow present in 2D imaging arrays maps very nicely into a 3D computational structure as information flows from circuit-tier to circuit-tier in the z-direction. To date, the MIT-LL 3D integration technology has been used to fabricate four different focal planes including: a 2-tier 64 x 64 imager with fully parallel per-pixel A/D conversion; a 3-tier 640 x 480 imager consisting of an imaging tier, an A/D conversion tier, and a digital signal processing tier; a 2-tier 1024 x 1024 pixel, 4-side-abutable imaging modules for tiling large mosaic focal planes, and a 3-tier Geiger-mode avalanche photodiode (APD) 3-D LIDAR array, using a 30 volt APD tier, a 3.3 volt CMOS tier, and a 1.5 volt CMOS tier. Recently, the 3D integration technology has been made available to the circuit design research community through DARPA-sponsored Multiproject fabrication runs. The first Multiproject Run (3DL1) completed fabrication in early 2006 and included over 30 different circuit designs from 21 different research groups. 3D circuit concepts explored in this run included stacked memories, field programmable gate arrays (FPGAs), and mixed-signal circuits. The second Multiproject Run (3DM2) is currently in fabrication and includes particle detector readouts designed by Fermilab. This talk will provide a brief overview of MIT-LL's 3D-integration process, discuss some of the focal plane applications where the technology is being applied, and provide a summary of some of the Multiproject Run circuit results.

  17. Ballistic imaging of biological media with collimated illumination and focal plane detection

    NASA Astrophysics Data System (ADS)

    Brezner, Barak; Cahen, Sarah; Glasser, Ziv; Sternklar, Shmuel; Granot, Er'el

    2015-07-01

    A simple, affordable method for imaging through biological tissue is investigated. The method consists of (1) imaging with a wavelength that has a relatively small scattering coefficient (1310 nm in this case) and (2) collimated illumination together with (3) focal plane detection to enhance the detection of the ballistic photons relative to the diffusive light. We demonstrate ballistic detection of an object immersed in a 1-cm-thick cuvette filled with 4% Intralipid, which is equivalent to ˜1 to 2 cm of skin tissue. With the same technology, a ballistic image of a 1-mm-wide object in 10-mm-thick chicken breast is also presented.

  18. Review of Concepts and Applications for Multispectral/Hyperspectral Focal Plane Array (FPA) Technology

    NASA Technical Reports Server (NTRS)

    McAdoo, James A.

    2001-01-01

    Multispectral, and ultimately hyperspectral, focal plane arrays (FPAs) represent the logical extension of two-color FPA technology, which has already shown its utility in military applications. Incorporating the spectral discrimination function directly in the FPA would offer the potential for orders-of-magnitude increase in remote sensor system performance. It would allow reduction or even elimination of optical components currently required to provide spectral discrimination in atmospheric remote sensors. The result would be smaller, simpler instruments with higher performance than exist today.

  19. Development and production of the H4RG-15 focal plane array

    NASA Astrophysics Data System (ADS)

    Blank, Richard; Beletic, James W.; Cooper, Donald; Farris, Mark; Hall, Donald N. B.; Hodapp, Klaus; Luppino, Gerard; Piquette, Eric; Xu, Min

    2012-07-01

    In preparation for the large number of infrared pixels required in the era of Extremely Large Telescopes, Teledyne, in partnership with the University of Hawaii and GL Scientific, has been funded to develop the next generation of largeformat infrared focal plane array for ground-based astronomy; the 4096 × 4096 pixel (15 micron pitch) H4RG-15. Teledyne has successfully designed, produced, and tested the first generation H4RG-15 prototype arrays. This paper reports on the functionality and performance test results of the H4RG-15 prototypes and provides status of the 2012 pilot production effort.

  20. Extrinsic charge-extraction device /XCED/ - An extrinsic-silicon focal-plane array architecture

    NASA Astrophysics Data System (ADS)

    Pocock, D. N.; Chiu, K. Y.; Missman, R. A.; Nuttall, D. E.

    1980-01-01

    The XCED (extrinsic charge-extraction device) is a unique focal-plane array structure designed for staring infrared-imaging applications. Extrinsic-silicon detectors, MOS integrating storage capacitors, and unique accumulation mode multiplexing devices are combined in a two-dimensional array within a single monolithic chip. Zinc-doped silicon has been studied and utilized to fabricate detectors sensitive in the 2 to 4 micron spectral band with BLIP operating temperatures above 110 K. The potentially severe problems for staring arrays of element-to-element nonuniformities and detector storage saturation have been solved. Preliminary results and thermal imagery are shown for a 16 x 16 element array.

  1. MUSTANG 2: A Large Focal Plane Array for the 100 m Green Bank Telescope

    NASA Astrophysics Data System (ADS)

    Dicker, S. R.; Ade, P. A. R.; Aguirre, J.; Brevik, J. A.; Cho, H. M.; Datta, R.; Devlin, M. J.; Dober, B.; Egan, D.; Ford, J.; Ford, P.; Hilton, G.; Irwin, K. D.; Mason, B. S.; Marganian, P.; Mello, M.; McMahon, J. J.; Mroczkowski, T.; Rosenman, M.; Tucker, C.; Vale, L.; White, S.; Whitehead, M.; Young, A. H.

    2014-09-01

    This paper describes MUSTANG 2, a 338 element focal plane array that is being built for the Green Bank Telescope. Each element consists of a profiled feedhorn coupled to two transition edge sensor bolometers, one for each polarization. Initial deployment will be with 32 detectors, but once fully populated, MUSTANG 2 will be capable of mapping a area to Jy in 1 h with good image fidelity on angular scales from to . As well as an instrument overview, the choice of bandpass and the design of the feeds, detectors and readout are given.

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

    SciTech Connect

    Langeveld, Willy; /SLAC

    2005-10-26

    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.

  3. Signal-to-noise analysis of Stokes parameters in division of focal plane polarimeters.

    PubMed

    Perkins, Robert; Gruev, Viktor

    2010-12-06

    An analysis of the temporal noise in the Stokes parameters computed by division of focal plane polarimeters is presented. Theoretical estimations of the Stokes parameter signal-to-noise ratios for CCD polarization imaging sensors with both 4-polarizer and 2-polarizer micropolarization filter arrays are derived. The theoretical derivation is verified with measurements from an integrated polarization imaging sensor composed of a CCD imaging array and aluminum nanowire polarization filters. The measured data obtained from the CCD polarimeters matches the theoretical derivations of the temporal noise model of the Stokes parameters.

  4. Design of the CRISM cryogenic system and focal plane assembly isolation system

    NASA Astrophysics Data System (ADS)

    Lees, Jeffrey; Schaefer, Ed; Fasold, Melisa

    2005-08-01

    This Paper will discuss the design of a triple redundant cryogenically cooled and isolated Focal Plane Assembly (FPA) for the Compact Remote Imaging Spectrometer for Mars (CRISM) instrument. The FPA is required to operate in the temperature range of 90 - 100K. The CRISM FPA isolation system was constructed from a ceramic fiber composite. The FPA was cooled by one of three cryocoolers individually connected to one of three diode heat pipes that were all connected to the FPA. The total heat load imposed by the isolation system was about 250 milliwatts at operating temperature. CRISM is expected to launch in August of 2005.

  5. Quantum Well and Quantum Dot Modeling for Advanced Infrared Detectors and Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Ting, David; Gunapala, S. D.; Bandara, S. V.; Hill, C. J.

    2006-01-01

    This viewgraph presentation reviews the modeling of Quantum Well Infrared Detectors (QWIP) and Quantum Dot Infrared Detectors (QDIP) in the development of Focal Plane Arrays (FPA). The QWIP Detector being developed is a dual band detector. It is capable of running on two bands Long-Wave Infrared (LWIR) and Medium Wavelength Infrared (MWIR). The same large-format dual-band FPA technology can be applied to Quantum Dot Infrared Photodetector (QDIP) with no modification, once QDIP exceeds QWIP in single device performance. Details of the devices are reviewed.

  6. Regional Stress Orientations and Slip Compatibility of Earthquake Focal Mechanism Nodal Planes in the New Madrid Seismic Zone

    NASA Astrophysics Data System (ADS)

    Hurd, O.; Zoback, M. D.

    2011-12-01

    In this study we revisit the question of slip on faults in the New Madrid seismic zone in the context of the regional stress field. Specifically, we utilize newly available data to investigate whether fault slip is compatible with the regional stress field and laboratory-determined coefficients of friction (as originally argued by M.D. Zoback and M.L. Zoback, Science, 1981) or if there is evidence for either local sources of stress or anomalously low fault strength. Ten new, well-constrained earthquake focal plane mechanisms from the New Madrid seismic zone are available to update regional stress data and two earthquake focal plane mechanisms originally published in the 1970's have recently been revised. Utilizing these data, we demonstrate that the earthquakes occur on nodal planes which are optimally-oriented for shear failure in the current stress field assuming hydrostatic pore pressure in the brittle crust and coefficients of friction (μ) of about 0.6. The average SHmax orientation inferred from P-axes of the 12 focal mechanisms is N84E +/- 21°, which is consistent with the overall trend of SHmax in the region. In a manner similar to the study by M.L. Zoback (JGR, 1992), which utilized a slightly smaller (and in two cases, less reliable) set of focal mechanisms in this area, we use the orientation of the focal mechanism nodal planes combined with independent stress data to investigate the compatibility of slip on both nodal planes in the current stress field. First, the relative magnitudes of the three principal stresses are calculated from the nodal plane and stress orientations. Next, we utilize Mohr-Coulomb failure criterion to calculate the theoretically-optimal orientation of a fault plane for different coefficients of friction. Lastly, we calculate the difference in orientation between the theoretically-optimal planes and the focal mechanism nodal planes and identify the nodal plane with the smaller difference as the preferred nodal plane. For μ = 0

  7. 3D numerical model for a focal plane view in case of mosaic grating compressor for high energy CPA chain.

    PubMed

    Montant, S; Marre, G; Blanchot, N; Rouyer, C; Videau, L; Sauteret, C

    2006-12-11

    An important issue, mosaic grating compressor, is studied to recompress pulses for multiPetawatt, high energy laser systems. Alignment of the mosaic elements is crucial to control the focal spot and thus the intensity on target. No theoretical approach analyses the influence of compressor misalignment on spatial and temporal profiles in the focal plane. We describe a simple 3D numerical model giving access to the focal plane view after a compressor. This model is computationally inexpensive since it needs only 1D Fourier transforms to access to the temporal profile. We present simulations of monolithic and mosaic grating compressors.

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

    PubMed Central

    Wang, Congzhi; Xiao, Yang; Xia, Jingjing; Qiu, Weibao; Zheng, Hairong

    2016-01-01

    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. PMID:27845751

  9. Conceptual design of wide-field focal plane with InGaAs image sensors

    NASA Astrophysics Data System (ADS)

    Komiyama, Y.; Nakaya, H.; Kashikawa, N.; Uchida, T.

    2016-08-01

    We present a conceptual design to implement wide-field focal plane assembly with InGaAs image sensors which are being tested intensively and reveled to be promising for astronomical use. InGaAs image sensors are sensitive up to 1.7 microns and would open a new window for the wide-field near-infrared (NIR) imaging survey once large format sensors are developed. The sensors are not necessarily cooled down to below 100 K, which is the case for prevailing NIR image sensors such as HgCdTe, enabling us to develop the NIR camera based on the technique developed for the CCD camera in optical wavelength. The major technical challenges to employ InGaAS image sensors for wide-field NIR camera are implementation of focal plane assembly and thermal design. In this article, we discuss these difficulties and show how we can conquer based on our experience to build Hyper Suprime-Cam, which is a wide-field imager with 116 2k4k CCDs attached to Subaru Telescope.

  10. Holographic optical tweezers combined with back-focal-plane displacement detection.

    PubMed

    Marsà, Ferran; Farré, Arnau; Martín-Badosa, Estela; Montes-Usategui, Mario

    2013-12-16

    A major problem with holographic optical tweezers (HOTs) is their incompatibility with laser-based position detection methods, such as back-focal-plane interferometry (BFPI). The alternatives generally used with HOTs, like high-speed video tracking, do not offer the same spatial and temporal bandwidths. This has limited the use of this technique in precise quantitative experiments. In this paper, we present an optical trap design that combines digital holography and back-focal-plane displacement detection. We show that, with a particularly simple setup, it is possible to generate a set of multiple holographic traps and an additional static non-holographic trap with orthogonal polarizations and that they can be, therefore, easily separated for measuring positions and forces with the high positional and temporal resolutions of laser-based detection. We prove that measurements from both polarizations contain less than 1% crosstalk and that traps in our setup are harmonic within the typical range. We further tested the instrument in a DNA stretching experiment and we discuss an interesting property of this configuration: the small drift of the differential signal between traps.

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

    PubMed

    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.

  12. Noise analysis for infrared focal plane arrays CMOS readout integrated circuit

    NASA Astrophysics Data System (ADS)

    Lin, Jiamu; Ding, Ruijun; Chen, Honglei; Shen, Xiao; Liu, Fei

    2008-12-01

    With the development of the infrared focal plane detectors, the internal noises in the infrared focal plane arrays (IRFPAs) CMOS readout integrated circuit gradually became an important factor of the development of the IRFPAs. The internal noises in IRFPAs CMOS readout integrated circuit are researched in this work. Part of the motivation for this work is to analyze the mechanism and influence of the internal noises in readout integrated circuit. And according to the signal transporting process, many kinds of internal noises are analyzed. According to the results of theory analysis, it is shown that 1/f noise, KTC noise and pulse switch noise have greater amplitude in frequency domain. These noises have seriously affected the performance of output signal. Also this work has frequency test on the signals of a readout integrated circuit chip which is using DI readout mode. After analyzing the frequency test results, it is shown that 1/f noises and pulse switch noises are the main components of the internal noises in IRFPAS CMOS readout integrated circuit and they are the noises which give a major impact to the output signal. In accordance with the type of noise, some design methods for noise suppression are put forward. And after the simulation of these methods with EDA software, the results show that noises have been reduced. The results of this work gave the referenced gist for improving the noise suppression design of IRFPAs CMOS readout integrated circuit.

  13. Range-gated imaging with an indium-gallium-arsenide-based focal plane array

    NASA Astrophysics Data System (ADS)

    Brubaker, Robert M.; Ettenberg, Martin H.; O'Grady, Matthew T.; Blessinger, Michael A.; Dries, J. C.

    2004-08-01

    Range-gated imaging using indium gallium arsenide based focal plane arrays enables both depth and intensity imaging with eye-safe lasers while remaining covert to night vision goggles. We report on a focal plane array consisting of an indium gallium arsenide photodiode array hybrid-integrated with a CMOS readout circuit, resulting in an all solid state device. A 5 V supply avoids the complication of high voltage supplies and improves reliability, while also allowing the device to be small and lightweight. The spectral sensitivity of InGaAs extends from 0.9 microns to 1.7 microns, allowing the use of commercially available pulsed lasers with 1.5 micron wavelength, several millijoule pulse energies, and nanosecond scale pulse durations. SUI is developing a 320 x 256 pixel imager with the ability to conduct range gated imaging with sub-100 ns gates, while also allowing a 16 ms integration time for imaging in a staring mode. The pixels are fabricated on a 25 micron pitch for a compact device, and all pixels are gated simultaneously for "snapshot" exposure. High in-pixel gain with nearly noiseless amplification and low dark current enable high sensitivity imaging from ultra-short gates to video rate imaging.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. A method for pulsed scannerless laser imaging using focal plane array

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi-peng; Wang, Ke-yong; Deng, Jia-hao; Hai, Yan

    2011-06-01

    Laser imaging techniques have advantages for EMI (Electro Magnetic Interference) immunity and abundant image information. This contribution describes the research activity on the scannerless laser imaging detection technique using direct detection aimed at laser fuze applications. The technique using a pulsed laser to illuminate the target and a focal plane array can be used as a receiver. The range information is achieved by means of a direct time of light measurement. Information about the reflectivity of the target is gathered by recording the amplitude of the received pulse. In this paper a high-repetition-frequency, narrow pulse semiconductor laser floodlight emitting system is designed; corresponding optics is used to generate the homogenously illuminated FOI (field of illumination). The echo of laser is collected by receiving optical system fed to focal plane array. Some experiments were done with the emitting and receiving systems that had been designed. Experiments show the validity and rationality of this method. The scannerless structure is robust and provides instantaneous snapshot-type imaging. Avoiding any moving mechanical parts, scannerless laser imaging system have distinct characteristics such as small, compact, high frame rate, wide field of view and high reliability. It is an optimal approach to realize laser imaging fuze.

  16. Solid-state image sensor with focal-plane digital photon-counting pixel array

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Pain, Bedabrata (Inventor)

    1995-01-01

    A photosensitive layer such as a-Si for a UV/visible wavelength band is provided for low light level imaging with at least a separate CMOS amplifier directly connected to each PIN photodetector diode to provide a focal-plane array of NxN pixels, and preferably a separate photon-counting CMOS circuit directly connected to each CMOS amplifier, although one row of counters may be time shared for reading out the photon flux rate of each diode in the array, together with a buffer memory for storing all rows of the NxN image frame before transfer to suitable storage. All CMOS circuitry is preferably fabricated in the same silicon layer as the PIN photodetector diode for a monolithic structure, but when the wavelength band of interest requires photosensitive material different from silicon, the focal-plane array may be fabricated separately on a different semiconductor layer bump-bonded or otherwise bonded for a virtually monolithic structure with one free terminal of each diode directly connected to the input terminal of its CMOS amplifier and digital counter for integration of the photon flux rate at each photodetector of the array.

  17. InstantScope: a low-cost whole slide imaging system with instant focal plane detection

    PubMed Central

    Guo, Kaikai; Liao, Jun; Bian, Zichao; Heng, Xin; Zheng, Guoan

    2015-01-01

    We report the development of a high-throughput whole slide imaging (WSI) system by adapting a cost-effective optomechanical add-on kit to existing microscopes. Inspired by the phase detection concept in professional photography, we attached two pinhole-modulated cameras at the eyepiece ports for instant focal plane detection. By adjusting the positions of the pinholes, we can effectively change the view angle for the sample, and as such, we can use the translation shift of the two pinhole-modulated images to identify the optimal focal position. By using a small pinhole size, the focal-plane-detection range is on the order of millimeter, orders of magnitude longer than the objective’s depth of field. We also show that, by analyzing the phase correlation of the pinhole-modulated images, we can determine whether the sample contains one thin section, folded sections, or multiple layers separated by certain distances – an important piece of information prior to a detailed z scan. In order to achieve system automation, we deployed a low-cost programmable robotic arm to perform sample loading and $14 stepper motors to drive the microscope stage to perform x-y scanning. Using a 20X objective lens, we can acquire a 2 gigapixel image with 14 mm by 8 mm field of view in 90 seconds. The reported platform may find applications in biomedical research, telemedicine, and digital pathology. It may also provide new insights for the development of high-content screening instruments. PMID:26417493

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

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    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 (<1 arcsec) and high flux ratio (>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

  20. Focal plane alignment and detector characterization for the Subaru prime focus spectrograph

    NASA Astrophysics Data System (ADS)

    Hart, Murdock; Barkhouser, Robert H.; Carr, Michael; Golebiowski, Mirek; Gunn, James E.; Hope, Stephen C.; Smee, Stephen A.

    2014-07-01

    We describe the infrastructure being developed to align and characterize the detectors for the Subaru Measure- ment of Images and Redshifts (SuMIRe) Prime Focus Spectrograph (PFS). PFS will employ four three-channel spectrographs with an operating wavelength range of 3800 °A to 12600 °A. Each spectrograph will be comprised of two visible channels and one near infrared (NIR) channel, where each channel will use a separate Schmidt camera to image the captured spectra onto their respective detectors. In the visible channels, Hamamatsu 2k × 4k CCDs will be mounted in pairs to create a single 4k × 4k detector, while the NIR channel will use a single Teledyne 4k × 4k H4RG HgCdTe device. The fast f/1.1 optics of the Schmidt cameras will give a shallow depth of focus necessitating an optimization of the focal plane array flatness. The minimum departure from flatness of the focal plane array for the visible channels is set the by the CCD flatness, typically 10 μm peak-to-valley. We will adjust the coplanarity for a pair of CCDs such that the flatness of the array is consistent with the flatness of the detectors themselves. To achieve this we will use an optical non-contact measurement system to measure surface flatness and coplanarity at both ambient and operating temperatures, and use shims to adjust the coplanarity of the CCDs. We will characterize the performance of the detectors for PFS consistent with the scientific goals for the project. To this end we will measure the gain, linearity, full well, quantum efficiency (QE), charge diffusion, charge transfer inefficiency (CTI), and noise properties of these devices. We also desire to better understand the non-linearity of the photon transfer curve for the CCDs, and the charge persistence/reciprocity problems of the HgCdTe devices. To enable the metrology and characterization of these detectors we are building two test cryostats nearly identical in design. The first test cryostat will primarily be used for the

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

    NASA Technical Reports Server (NTRS)

    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.

  2. Visualization of Subsurface Defects in Composites using a Focal Plane Array Infrared Camera

    NASA Technical Reports Server (NTRS)

    Plotnikov, Yuri A.; Winfree, William P.

    1999-01-01

    A technique for enhanced defect visualization in composites via transient thermography is presented in this paper. The effort targets automated defect map construction for multiple defects located in the observed area. Experimental data were collected on composite panels of different thickness with square inclusions and flat bottom holes of different depth and orientation. The time evolution of the thermal response and spatial thermal profiles are analyzed. The pattern generated by carbon fibers and the vignetting effect of the focal plane array camera make defect visualization difficult. An improvement of the defect visibility is made by the pulse phase technique and the spatial background treatment. The relationship between a size of a defect and its reconstructed image is analyzed as well. The image processing technique for noise reduction is discussed.

  3. Status of AlGaN based focal plane arrays for UV solar blind detection

    NASA Astrophysics Data System (ADS)

    Reverchon, Jean-Luc; Mazzeo, Giovanni; Dussaigne, Amélie; Duboz, Jean-Yves

    2005-10-01

    The fast development of nitrides has given the opportunity to investigate AlGaN as a material for ultraviolet solar blind detection in competition with technologies based on photocathodes, MCP intensifiers, back thinned CCD or hybrid CMOS focal plane arrays. All of the them must be associated to UV blocking filters. These new detectors present both an intrinsic spectral selectivity and an extremely low dark current at room temperature. First we will present the ultimate properties of the AlGaN based devices. These spectral properties are analysed in regards to the sharp cut off required for solar blind detection around 280nm, and we will quantify how the stringent difficulties to achieve solar blind filters can be reduced. We also investigated the electrical capabilities of Schottky diodes or Metal-Semiconductor-Metal (MSM) technologies to detect extremely low UV signal. We will especially present results from a linear array based on a CCD readout multiplexor.

  4. Methodology for testing infrared focal plane arrays in simulated nuclear radiation environments

    NASA Astrophysics Data System (ADS)

    Divita, E. L.; Mills, R. E.; Koch, T. L.; Gordon, M. J.; Wilcox, R. A.; Williams, R. E.

    1992-07-01

    This paper summarizes test methodology for focal plane array (FPA) testing that can be used for benign (clear) and radiation environments, and describes the use of custom dewars and integrated test equipment in an example environment. The test methodology, consistent with American Society for Testing Materials (ASTM) standards, is presented for the total accumulated gamma dose, transient dose rate, gamma flux, and neutron fluence environments. The merits and limitations of using Cobalt 60 for gamma environment simulations and of using various fast-neutron reactors and neutron sources for neutron simulations are presented. Test result examples are presented to demonstrate test data acquisition and FPA parameter performance under different measurement conditions and environmental simulations.

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

    NASA Technical Reports Server (NTRS)

    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.; Crites, A. T.; Essinger-Hileman, T.; Fox, A.; George, E. M.; Halverson, N. W.; Harrington, N. L.; Henning, J. W.; Hilton, G. C.; Irwin, K. D.; Li, D.; Niemack, M. D.; Nibarger, J. P.; VanLanen, J.; Newburgh, L. B.; Parker, L. P.

    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.

  6. ACE16k: a 128x128 focal plane analog processor with digital I/O.

    PubMed

    Cembrano, Gustavo Liñan; Rodríguez-Vázquez, Angel; Espejo Meana, Servando; Domínguez-Castro, Rafael

    2003-12-01

    This paper presents a new generation 128x128 Focal-Plane Analog Programmable Array Processor -FPAPAP, from a system level perspective. It has been manufactured in a 0.35 microm standard digital 1P-5M CMOS technology. It has been designed to achieve the high-speed and moderate-accuracy -8b- requirements of most real time -early-vision applications. External data interchange and control are completely digital. The chip contains close to four million transistors, 90% of them working in analog mode. It achieves peak computing values of 0.33TeraOPS while keeping power consumption at reasonable limits -82.5GOPS/W. Preliminary experimental results are also provided in the paper.

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

    PubMed

    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 8 degrees of freedom. Images are simulated given misalignment parameters using ZEMAX software. We perform a principal component analysis on the simulated data set to obtain Karhunen-Loève 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 simulated and experimental results of the full system in operation.

  8. Time resolved photo-luminescent decay characterization of mercury cadmium telluride focal plane arrays

    DOE PAGES

    Soehnel, Grant

    2015-01-20

    The minority carrier lifetime is a measurable material property that is an indication of infrared detector device performance. To study the utility of measuring the carrier lifetime, an experiment has been constructed that can time resolve the photo-luminescent decay of a detector or wafer sample housed inside a liquid nitrogen cooled Dewar. Motorized stages allow the measurement to be scanned over the sample surface, and spatial resolutions as low as 50µm have been demonstrated. A carrier recombination simulation was developed to analyze the experimental data. Results from measurements performed on 4 mercury cadmium telluride focal plane arrays show strong correlationmore » between spatial maps of the lifetime, dark current, and relative response.« less

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Time resolved photo-luminescent decay characterization of mercury cadmium telluride focal plane arrays

    SciTech Connect

    Soehnel, Grant

    2015-01-20

    The minority carrier lifetime is a measurable material property that is an indication of infrared detector device performance. To study the utility of measuring the carrier lifetime, an experiment has been constructed that can time resolve the photo-luminescent decay of a detector or wafer sample housed inside a liquid nitrogen cooled Dewar. Motorized stages allow the measurement to be scanned over the sample surface, and spatial resolutions as low as 50µm have been demonstrated. A carrier recombination simulation was developed to analyze the experimental data. Results from measurements performed on 4 mercury cadmium telluride focal plane arrays show strong correlation between spatial maps of the lifetime, dark current, and relative response.

  11. Long-Wavelength Infrared (LWIR) Quantum Dot Infrared Photodetector (QDIP) Focal Plane Array

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath D.; Bandara, S. V.; Liu, J. K.; Hill, C. J.; Rafol, S. B.; Mumolo, J. M.; Shott, C. A.

    2006-01-01

    We have exploited the artificial atomlike properties of epitaxially self-assembled quantum dots for the development of high operating temperature long wavelength infrared (LWIR) focal plane arrays. Quantum dots are nanometer-scale islands that form spontaneously on a semiconductor substrate due to lattice mismatch. QDIPs are expected to outperform quantum well infrared detectors (QWIPs) and are expected to offer significant advantages over II-VI material based focal plane arrays. QDIPs are fabricated using robust wide bandgap III-V materials which are well suited to the production of highly uniform LWIR arrays. We have used molecular beam epitaxy (MBE) technology to grow multi-layer LWIR quantum dot structures based on the InAs/InGaAs/GaAs material system. JPL is building on its significant QWIP experience and is basically building a Dot-in-the-Well (DWELL) device design by embedding InAs quantum dots in a QWIP structure. This hybrid quantum dot/quantum well device offers additional control in wavelength tuning via control of dot-size and/or quantum well sizes. In addition the quantum wells can trap electrons and aide in ground state refilling. Recent measurements have shown a 10 times higher photoconductive gain than the typical QWIP device, which indirectly confirms the lower relaxation rate of excited electrons (photon bottleneck) in QDPs. Subsequent material and device improvements have demonstrated an absorption quantum efficiency (QE) of approx. 3%. Dot-in-the-well (DWELL) QDIPs were also experimentally shown to absorb both 45 deg. and normally incident light. Thus we have employed a reflection grating structure to further enhance the quantum efficiency. JPL has demonstrated wavelength control by progressively growing material and fabricating devices structures that have continuously increased in LWIR response. The most recent devices exhibit peak responsivity out to 8.1 microns. Peak detectivity of the 8.1 micrometer devices has reached approx. 1 x 10(exp 10

  12. Strained-layer superlattice focal plane array having a planar structure

    DOEpatents

    Kim, Jin K.; Carroll, Malcolm S.; Gin, Aaron; Marsh, Phillip F.; Young, Erik W.; Cich, Michael J.

    2010-07-13

    An infrared focal plane array (FPA) is disclosed which utilizes a strained-layer superlattice (SLS) formed of alternating layers of InAs and In.sub.xGa.sub.1-xSb with 0.ltoreq.x.ltoreq.0.5 epitaxially grown on a GaSb substrate. The FPA avoids the use of a mesa structure to isolate each photodetector element and instead uses impurity-doped regions formed in or about each photodetector for electrical isolation. This results in a substantially-planar structure in which the SLS is unbroken across the entire width of a 2-D array of the photodetector elements which are capped with an epitaxially-grown passivation layer to reduce or eliminate surface recombination. The FPA has applications for use in the wavelength range of 3-25 .mu.m.

  13. First Photometric Performance Results of the Kepler Single String Focal Plane

    NASA Astrophysics Data System (ADS)

    Koch, David G.; Borucki, W.; Dunham, E.; Geary, J.; Jenkins, J.; Argabright, V.; Bauer, R.; Dumont, C.; McArthur, S.; Peters, D.; Philbrick, R.; Rudeen, A.; VanCleve, J.; Witteborn, F.

    2006-12-01

    The Kepler Mission is designed to detect Earth-size and smaller exoplanets using space based transit photometry. An engineering model (EM) consisting of two flight-like CCDs and the associated control and data acquisition boards representing a portion of the flight focal plane has been built to qualify the flight design. In addition to all of the flight environmental qualification tests, this single-string EM has been photometrically tested using the Kepler Technology Demonstration facility (Koch et al, SPIE, 4013, 508-519, 2000), which includes a star field simulator and the ability to generate Earth-size transit signals in various stars. We present a description of the test methodology, the photometric performance test results and a comparison to the mission design requirements.

  14. W-band planar antennas for next generation sub-millimeter focal plane arrays

    NASA Astrophysics Data System (ADS)

    Deo, Prafulla; Robinson, Matthew; Maffei, Bruno; Pisano, Giampaolo; Trappe, Neil

    2016-07-01

    Current and future generations of astronomical instruments in the millimetre (mm) and sub-mm range are in need of increased sensitivity through the use of ever larger focal planes with 1000s of pixels. Mass, dimensions and manufacture requirements, mainly for new space missions, is driving the technology to go from feedhorn, and generally waveguide based cold optics to planar coupled detectors, while maintaining RF performance. The present results of a current ESA TRP are presented with respect to the work on planar antennae that will be coupled to cold bolometric detectors through the use of planar mesh lenses. Two planar antennae operating at W-band are developed, namely, a broadband sinuous antenna and a variation on the classical dual-slot antenna to realise multi-band functionality.

  15. A math model for high velocity sensoring with a focal plane shuttered camera.

    NASA Technical Reports Server (NTRS)

    Morgan, P.

    1971-01-01

    A new mathematical model is presented which describes the image produced by a focal plane shutter-equipped camera. The model is based upon the well-known collinearity condition equations and incorporates both the translational and rotational motion of the camera during the exposure interval. The first differentials of the model with respect to exposure interval, delta t, yield the general matrix expressions for image velocities which may be simplified to known cases. The exposure interval, delta t, may be replaced under certain circumstances with a function incorporating blind velocity and image position if desired. The model is tested using simulated Lunar Orbiter data and found to be computationally stable as well as providing excellent results, provided that some external information is available on the velocity parameters.

  16. Low dark current LWIR HgCdTe focal plane arrays at AIM

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    Cryogenically cooled HgCdTe (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. AIM will present its latest results on n-on-p as well as p-on-n low dark current planar MCT photodiode focal plane detector arrays at cut-off wavelengths >11 μm at 80 K. Dark current densities below the Rule'07 have been demonstrated for n-on-p devices. Slightly higher dark current densities and excellent cosmetics with very low cluster and point defect densities have been demonstrated for p-on-n devices.

  17. The focal plane adaptive optics test box of the Observatoire du Mont-Mégantic

    NASA Astrophysics Data System (ADS)

    Deschênes, William; Brousseau, Denis; Lavigne, Jean-Francois; Thibault, Simon; Véran, Jean-Pierre

    2014-08-01

    With the upcoming construction of Extremely Large Telescopes, several existing technologies are being pushed beyond their performance limit and it becomes essential to develop and evaluate new alternatives. The "Observatoire du Mont Mégantic" (OMM) hosts a telescope having a 1.6-meter diameter primary. The OMM telescope is known to be an excellent location to develop and test precursor instruments which are then upscaled to larger telescopes (ex. SPIOMM which led to SITELLE at the CFHT). We present a specifically designed focal plane box for the OMM which will allow to evaluate, directly on-sky, the performance of a number of next generation adaptive optics related technologies The system will able us to compare the performance of several new wavefront sensors in contrast with the current standard, the Shack-Hartman wavefront sensor.

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

    PubMed Central

    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

  19. A focal-plane detector for the recoil-mass spectrometer of LNL

    NASA Astrophysics Data System (ADS)

    Guerrieri, A.; Maron, G.; Montagnoli, G.; Napoli, D. R.; Prete, G.

    1990-12-01

    A focal-plane detector for a recoil-mass spectrometer has been developed. It consists of a 14 × 14 cm 2 position-sensitive parallel-plate avalanche counter backed by a 43 cm long Bragg chamber. Both detectors work in the same gas volume thus reducing the dead layers. The intrinsic resolution of the position detector is ±0.5 mm, and an overall timing resolution of 660 ps FWHM was measured with 5.5 MeV α-particles. The Bragg chamber allows the identification of elements with energy high enough to overcome the Bragg peak: in all cases it allows the separation between the reaction channels and the beam scattering. The detector has already been used with a good reliability in a variety of transfer and fusion experiments at the LNL Recoil Mass Spectrometer.

  20. Argus: A W-band 16-pixel focal plane array for the Green Bank Telescope

    NASA Astrophysics Data System (ADS)

    Devaraj, Kiruthika; Church, Sarah; Cleary, Kieran; Frayer, David; Gawande, Rohit; Goldsmith, Paul; Gundersen, Joshua; Harris, Andrew; Kangaslahti, Pekka; Readhead, Tony; Reeves, Rodrigo; Samoska, Lorene; Sieth, Matt; Voll, Patricia

    2015-05-01

    We are building Argus, a 16-pixel square-packed focal plane array that will cover the 75-115.3 GHz frequency range on the Robert C. Byrd Green Bank Telescope (GBT). The primary research area for Argus is the study of star formation within our Galaxy and nearby galaxies. Argus will map key molecules that trace star formation, including carbon monoxide (CO) and hydrogen cyanide (HCN). An additional key science area is astrochemistry, which will be addressed by observing complex molecules in the interstellar medium, and the study of formation of solar systems, which will be addressed by identifying dense pre-stellar cores and by observing comets in our solar system. Argus has a highly scalable architecture and will be a technology path finder for larger arrays. The array is modular in construction, which will allow easy replacement of malfunctioning and poorly performing components.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Development of a 2K x 2K GaAs QWIP Focal Plane Array

    NASA Technical Reports Server (NTRS)

    Jhabvala, M.; Choi, K.; Jhabvala, C.; Kelly, D.; Hess, L.; Ewin, A.; La, A.; Wacynski, A.; Sun, J.; Adachi, T.; Costen, N.; Ni, Q.; Snodgrass, Stephen; Foltz, Roger

    2013-01-01

    We are developing the next generation of GaAs Quantum Well Infrared Photodetector (QWIP) focal plane arrays (FPAs) in preparation for future NASA space-borne Earth observing missions. It is anticipated that these missions will require both wider ground spatial coverage as well as higher ground imaging resolution. In order to demonstrate our capability in meeting these future goals we have taken a two-tiered approach in the next stage of advanced QWIP focal plane array development. We will describe our progress in the development of a 512 x 3,200 (512 x 3K) array format for this next generation thermal imaging array for the NASA Landsat project. However, there currently is no existing readout integrated circuit (ROIC) for this format array.so to demonstrate the ability to scale-up an existing ROIC we developed a 1,920 x 2,048 (2K x 2K) array and it hybridized to a Raytheon SB419 CTIA readout integrated circuit that was scaled up from their existing 512 x 640 SB339 ROIC. Two versions of the 512 x 3K QWIP array were fabricated to accommodate a future design scale-up of both the Indigo 9803 ROIC based on a 25 micron pixel dimension and a scale up of the Indigo 9705 ROIC based on a 30 micron pixel dimension. Neither readout for the 512 x 3K has yet to be developed but we have fabricated both versions of the array. We describe the design, development and test results of this effort as well as the specific applications these FPAs are intended to address.

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

    NASA Technical Reports Server (NTRS)

    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.

  4. ART-XC/SRG: status of the x-ray focal plane detector development

    NASA Astrophysics Data System (ADS)

    Levin, Vasily; Pavlinsky, Mikhail; Akimov, Valeriy; Kuznetsova, Maria; Rotin, Alexey; Krivchenko, Alexander; Lapshov, Igor; Oleinikov, Vladimir

    2014-07-01

    The Russian Space Research Institute (IKI) has developed CdTe detectors for the focal plane of the ART-XC/SRG instrument. The CdTe crystal has dimensions about 30 × 30 × 1 mm. Top and bottom sides of the detector each contain 48 strips and a guard ring. The ASIC VA64TA1 is connected to the CdTe crystal by AC-coupling for both DSSD sides. This approach allows one to have the same ground level for both electronic parts and to operate detectors with different leakage currents without reconfiguration of the VA64TA1 chips. One CdTe crystal and two ASICs are integrated with thermal sensors and Peltier cooler in a big hybrid integrated circuit. This detector is hermetically sealed by a cover with beryllium window. For ground testing the detector volume is filled with dry nitrogen. Peltier cooler is used during ground tests only. Together with the hermetic case package it allows us to operate the detector at low temperature during all ART-XC telescope development tests. When in space, the detector cooling will be provided by a radiator and heat pipes. Polarization rate temperature and voltage dependences as well as splitting charges between electrodes are being studied. IKI manufactured dozen X-ray cameras with detectors and supporting electronics for EM, QM and flight model of the ART-XC telescope. Spectroscopic and imaging performances of the detectors were tested on the IKI's X-Ray Calibration Facility. Current status of the focal plane detector development and testing will be presented.

  5. Monolithic in-based III-V compound semiconductor focal plane array cell with single stage CCD output

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Cunningham, Thomas J. (Inventor); Krabach, Timothy N. (Inventor); Staller, Craig O. (Inventor)

    1995-01-01

    A monolithic semiconductor imager includes an indium-based III-V compound semiconductor monolithic active layer of a first conductivity type, an array of plural focal plane cells on the active layer, each of the focal plane cells including a photogate over a top surface of the active layer, a readout circuit dedicated to the focal plane cell including plural transistors formed monolithically with the monolithic active layer and a single-stage charge coupled device formed monolithically with the active layer between the photogate and the readout circuit for transferring photo-generated charge accumulated beneath the photogate during an integration period to the readout circuit. The photogate includes thin epitaxial semiconductor layer of a second conductivity type overlying the active layer and an aperture electrode overlying a peripheral portion of the thin epitaxial semiconductor layer, the aperture electrode being connectable to a photogate bias voltage.

  6. Monolithic in-based III-V compound semiconductor focal plane array cell with single stage CCD output

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Cunningham, Thomas J. (Inventor); Krabach, Timothy N. (Inventor); Staller, Craig O. (Inventor)

    1994-01-01

    A monolithic semiconductor imager includes an indium-based III-V compound semiconductor monolithic active layer of a first conductivity type, an array of plural focal plane cells on the active layer, each of the focal plane cells including a photogate over a top surface of the active layer, a readout circuit dedicated to the focal plane cell including plural transistors formed monolithically with the monolithic active layer and a single-stage charge coupled device formed monolithically with the active layer between the photogate and the readout circuit for transferring photo-generated charge accumulated beneath the photogate during an integration period to the readout circuit. The photogate includes thin epitaxial semiconductor layer of a second conductivity type overlying the active layer and an aperture electrode overlying a peripheral portion of the thin epitaxial semiconductor layer, the aperture electrode being connectable to a photogate bias voltage.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed

    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.

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

    SciTech Connect

    Ma, Wei; Wen, Yongzheng; Yu, Xiaomei

    2015-03-16

    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 SiN{sub x} 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 SiN{sub x} as the absorbers, respectively. The performance improvement was verified by the evaluation of the absorbers as well as the imaging results of both FPAs.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Tolic-Noerrelykke, Simon F.; Schaeffer, Erik; Howard, Jonathon; Pavone, Francesco S.; Juelicher, Frank; Flyvbjerg, Henrik

    2006-10-15

    We explain and demonstrate a new method of force and position calibrations for optical tweezers with back-focal-plane photodetection. The method combines power spectral measurements of thermal motion and the response to a sinusoidal motion of a translation stage. It consequently does not use the drag coefficient of the trapped object as an input. Thus, neither the viscosity, nor the size of the trapped object, nor its distance to nearby surfaces needs to be known. The method requires only a low level of instrumentation and can be applied in situ in all spatial dimensions. It is both accurate and precise: true values are returned, with small error bars. We tested this experimentally, near and far from surfaces in the lateral directions. Both position and force calibrations were accurate to within 3%. To calibrate, we moved the sample with a piezoelectric translation stage, but the laser beam could 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.

  13. Present-day Focal Mechanisms and Stress Field of the Sichuan-Yunnan Active Block and Its Adjacent Region

    NASA Astrophysics Data System (ADS)

    zhao, cuiping; luo, jun; zhou, lianqing

    2013-04-01

    Focal mechanism solutions together with the depths of 66 M 3.5 moderate earthquakes occurred in the Sichuan Yunnan active block and its adjacent regions from Aug.1st, 2007 to Sep.15th, 2012was obtained by CAP method. Furthermore, by combining the results with the focal mechanism solutions from Harvard University, we investigated the characteristics of the stress field in the study area. We discussed the spatial distribution of the focal mechanisms and the focal depths, and then analyzed its dynamics. Four conclusions are drawn as follows. (1)Focal mechanism solutions show zoning characteristic. Along the ANH-ZMH-XJ faults(the eastern border of Sichuan-Yunnan block), the earthquakes are mostly left-lateral strike-slip mechanism. Along the HSH fault, the earthquakes are mostly right-lateral strike-slip mechanism. Around the XGLL block and in its interior, there exists remarkable normal fault mechanism with different fault striking and direction of P and T stress axis. Along the arc boundary of Sichuan-Yunnan block with the Sichuan basin, the earthquakes are reverse fault mechanism. (2) The inversed regional stress field shows complicated local feature. On and to the east side of the eastern border of Sichuan-Yunnan block, the stress field is similar with the stress field of the Eastern China block, which is from the relative motion of Philippine plate towards the Urasia plate. Whereas to the west side of the eastern border of Sichuan-Yunnan block, the stress field is much more complicated, indicting the strong influence of local structures to the stress field, especially the NE striking of JPS-YL over-thrusting tectonic structure located in the interior of Sichuan-Yunnan block.(3)The moment center depths of events occurred in the Sichuan-Yunnan active block are within 15km deep, and mostly among 5~15km, suggesting that the brittle seismic layer is among the depth of 5~15km in the upper and middle crust.

  14. CdTe focal plane detector for hard x-ray focusing optics

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

    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 mm x 20 mm CdTe-based detector with 250 μm square pixels (80x80 pixels) which achieves 1 keV FWHM @ 60 keV and gives full spectroscopy between 5 keV and 200 keV. An added advantage of these detectors is that they have a full-frame readout rate of 10 kHz. Working with NASA Goddard Space Flight Center and Marshall Space Flight Center, 4 of these 1mm-thick CdTe detectors are tiled into a 2x2 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 flightsuitable 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.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  17. High Sensitivity Long-Wavelength Infrared QWIP Focal Plane Array Based Instrument for Remote Sensing of Icy Satellites

    NASA Technical Reports Server (NTRS)

    Gunapala, S.; Bandara, S.; Ivanov, A.

    2003-01-01

    GaAs based Quantum Well Infrared Photodetector (QWIP) technology has shown remarkable success in advancing low cost, highly uniform, high-operability, large format multi-color focal plane arrays. QWIPs afford greater flexibility than the usual extrinsically doped semiconductor IR detectors. The wavelength of the peak response and cutoff can be continuously tailored over a range wide enough to enable light detection at any wavelength range between 6 and 20 micron. The spectral band-width of these detectors can be tuned from narrow (Deltalambda/lambda is approximately 10%) to wide (Deltalambda/lambda is approximately 40%) allowing various applications. Furthermore, QWIPs offer low cost per pixel and highly uniform large format focal plane arrays due to mature GaAs/AlGaAs growth and processing technologies. The other advantages of GaAs/AlGaAs based QWIPS are higher yield, lower l/f noise and radiation hardness (1.5 Mrad). In this presentation, we will discuss our recent demonstrations of 640x512 pixel narrow-band, broad-band, multi-band focal plane arrays, and the current status of the development of 1024x1024 pixel long-wavelength infrared QWIP focal plane arrays.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  19. Low dark current LWIR and VLWIR HgCdTe focal plane arrays at AIM

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    In this paper AIM presents an update on its results for 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 640×512 pixel format. The arrays are stitched from two 512×320 pixel photodiode arrays at a 20μm pixel 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 over a wide operating temperature range. The improvements made allow for the same dark current performance at a 20K higher operating temperature than with previous AIM technology. The demonstrated detector performance paces the way for a new generation of higher operating temperature low SWaP LWIR MCT FPAs with a <30mK NETD up to a 110K detector operating temperature and with good operability. Alternatively, lower dark currents at common operating temperatures may be attained, enabling cutting edge next generation LWIR/VLWIR detectors for space instruments.

  20. NOTE: Design and fabrication of a high sensitivity focal plane array for uncooled IR imaging

    NASA Astrophysics Data System (ADS)

    Yu, Xiaomei; Yi, Yuliang; Ma, Shenglin; Liu, Ming; Liu, Xiaohua; Dong, Liquan; Zhao, Yuejin

    2008-05-01

    This note reports on the development of a novel cantilever-based focal plane array (FPA) for uncooled infrared (IR) imaging. The FPA of 160 × 120 pixels consisted of a 1 µm thick low stress SiNx structure layer, a thin gold reflection layer and a thick gold bimaterial layer. A bulk silicon process that includes silicon-glass anodic bonding and deep reactive ion etching techniques was developed selectively to remove the substrate silicon and form silicon frames for every FPA pixel. The thermomechanical sensitivity of the cantilever pixel was measured as 0.11 µm K-1, the noise-equivalent temperature difference of the FPA was theoretically estimated to be below 60 mK and the response time was calculated to be 15 ms. An optical readout system was used to measure deflections of all cantilevers in the FPA simultaneously, and thermal images of the human body were captured in good time. One of the unique advantages of this honeycomb-like FPA is the selective removal of the silicon substrate, which could increase the IR absorption efficiency by 48% compared with that fabricated by a traditional surface sacrificial layer process.

  1. CCD Centroiding Experiment for Correcting a Distorted Image on the Focal Plane

    NASA Astrophysics Data System (ADS)

    Yano, Taihei; Araki, Hiroshi; Gouda, Naoteru; Kobayashi, Yukiyasu; Tsujimoto, Takuji; Nakajima, Tadashi; Kawano, Nobuyuki; Tazawa, Seiichi; Yamada, Yoshiyuki; Hanada, Hideo; Asari, Kazuyoshi; Tsuruta, Seiitsu

    2006-10-01

    JASMINE (Japan Astrometry Satellite Mission for Infrared Exploration) and ILOM (In situ Lunar Orientation Measurement) are space missions that are in progress at the National Astronomical Observatory of Japan. These two projects require a common astrometric technique to obtain precise positions of star images on solid-state detectors in order to accomplish their objectives. In the laboratory, we have carried out measurements of the centroid of artificial star images on a CCD array in order to investigate the precision of the positions of the stars, using an algorithm for estimating them from photon-weighted means of the stars. In the calibration of the position of a star image at the focal plane, we have also taken into account the lowest order distortion due to optical aberrations, which is proportional to the cube of the distance from the optical axis. Accordingly, we find that the precision of the measurement for the positions of the stars reaches below 1/100 pixel for one measurement.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. New data acquisition system for the focal plane polarimeter of the Grand Raiden spectrometer

    SciTech Connect

    Tamii, A.; Sakaguchi, H.; Takeda, H.; Yosoi, M.; Akimune, H.; Fujiwara, M.; Ogata, H.; Tanaka, M.; Togawa, H.

    1996-10-01

    This paper describes a new data acquisition system for the focal plane polarimeter of the Grand Raiden spectrometer at the Research Center for Nuclear Physics (RCNP) in Osaka, Japan. Data are acquired by a Creative Electronic Systems (CES) Starburst, which is a CAMAC auxiliary crate controller equipped with a Digital Equipment Corporation (DEC) J11 microprocessor., The data on the Starburst are transferred to a VME single-board computer. A VME reflective memory module broadcasts the data to other systems through a fiber-optic link. A data transfer rate of 2.0 Mbytes/s between VME modules has been achieved by reflective memories. This rate includes the overhead of buffer management. The overall transfer rate, however, is limited by the performance of the Starburst to about 160 Kbytes/s at maximum. In order to further improve the system performance, the authors developed a new readout module called the Rapid Data Transfer Module (RDTM). RDTM`s transfer data from LeCroy PCOS III`s or 4298`s, and FERA/FERET`s directly to CES 8170 High Speed Memories (HSM) in VME crates. The data transfer rate of the RDTM from PCOS III`s to the HSM is about 4 Mbytes/s.

  4. Coronagraph Focal-Plane Phase Masks Based on Photonic Crystal Technology: Recent Progress and Observational Strategy

    NASA Technical Reports Server (NTRS)

    Murakami, Naoshi; Nishikawa, Jun; Sakamoto, Moritsugu; Ise, Akitoshi; Oka, Kazuhiko; Baba, Naoshi; Murakami, Hiroshi; Tamura, Motohide; Traub, Wesley A.; Mawet, Dimitri; Moody, Dwight C.; Kern, Brian D.; Trauger, John T.; Serabyn, Eugene; Hamaguchi, Shoki; Oshiyama, Fumika

    2012-01-01

    Photonic crystal, an artificial periodic nanostructure of refractive indices, is one of the attractive technologies for coronagraph focal-plane masks aiming at direct imaging and characterization of terrestrial extrasolar planets. We manufactured the eight-octant phase mask (8OPM) and the vector vortex mask (VVM) very precisely using the photonic crystal technology. Fully achromatic phase-mask coronagraphs can be realized by applying appropriate polarization filters to the masks. We carried out laboratory experiments of the polarization-filtered 8OPM coronagraph using the High-Contrast Imaging Testbed (HCIT), a state-of-the-art coronagraph simulator at the Jet Propulsion Laboratory (JPL). We report the experimental results of 10-8-level contrast across several wavelengths over 10% bandwidth around 800nm. In addition, we present future prospects and observational strategy for the photonic-crystal mask coronagraphs combined with differential imaging techniques to reach higher contrast. We proposed to apply a polarization-differential imaging (PDI) technique to the VVM coronagraph, in which we built a two-channel coronagraph using polarizing beam splitters to avoid a loss of intensity due to the polarization filters. We also proposed to apply an angular-differential imaging (ADI) technique to the 8OPM coronagraph. The 8OPM/ADI mode avoids an intensity loss due to a phase transition of the mask and provides a full field of view around central stars. We present results of preliminary laboratory demonstrations of the PDI and ADI observational modes with the phase-mask coronagraphs.

  5. Evolution of miniature detectors and focal plane arrays for infrared sensors

    NASA Technical Reports Server (NTRS)

    Watts, Louis A.

    1993-01-01

    Sensors that are sensitive in the infrared spectral region have been under continuous development since the WW2 era. A quest for the military advantage of 'seeing in the dark' has pushed thermal imaging technology toward high spatial and temporal resolution for night vision equipment, fire control, search track, and seeker 'homing' guidance sensing devices. Similarly, scientific applications have pushed spectral resolution for chemical analysis, remote sensing of earth resources, and astronomical exploration applications. As a result of these developments, focal plane arrays (FPA) are now available with sufficient sensitivity for both high spatial and narrow bandwidth spectral resolution imaging over large fields of view. Such devices combined with emerging opto-electronic developments in integrated FPA data processing techniques can yield miniature sensors capable of imaging reflected sunlight in the near IR and emitted thermal energy in the Mid-wave (MWIR) and longwave (LWIR) IR spectral regions. Robotic space sensors equipped with advanced versions of these FPA's will provide high resolution 'pictures' of their surroundings, perform remote analysis of solid, liquid, and gas matter, or selectively look for 'signatures' of specific objects. Evolutionary trends and projections of future low power micro detector FPA developments for day/night operation or use in adverse viewing conditions are presented in the following test.

  6. Using a focal-plane array to estimate antenna pointing errors

    NASA Technical Reports Server (NTRS)

    Zohar, S.; Vilnrotter, V. A.

    1991-01-01

    The use of extra collecting horns in the focal plane of an antenna as a means of determining the Direction of Arrival (DOA) of the signal impinging on it, provided it is within the antenna beam, is considered. Our analysis yields a relatively simple algorithm to extract the DOA from the horns' outputs. An algorithm which, in effect, measures the thermal noise of the horns' signals and determines its effect on the uncertainty of the extracted DOA parameters is developed. Both algorithms were implemented in software and tested in simulated data. Based on these tests, it is concluded that this is a viable approach to the DOA determination. Though the results obtained are of general applicability, the particular motivation for the present work is their application to the pointing of a mechanically deformed antenna. It is anticipated that the pointing algorithm developed for a deformed antenna could be obtained as a small perturbation of the algorithm developed for an undeformed antenna. In this context, it should be pointed out that, with a deformed antenna, the array of horns and its associated circuitry constitute the main part of the deformation-compensation system. In this case, the pointing system proposed may be viewed as an additional task carried out by the deformation-compensation hardware.

  7. A novel readout method for focal plane array imaging in the presence of large dark current

    NASA Astrophysics Data System (ADS)

    Qiu, Changqing

    1999-08-01

    This research was an investigation of a novel readout method for focal plane array (FPA) optical imaging, especially for very sensitive detectors with large dark current. The readout method is based on periodically blocking the optical input enabling the removal of the dark current integration from the output. The research demonstrated that it is feasible to modulate the optical input with the designed readout circuit and thus achieve longer signal integration time to enhance the signal-to- noise ratio. Study of a proposed circuit model showed that in theory the correlated readout method could increase the output voltage swing and reduce the noise level by attenuating low frequency noise, thereby effectively improving the FPA dynamic range. Circuits based on standard CMOS circuitry were designed, simulated by PSpice, fabricated using Orbit 2μm n-well technology, and tested with a PI-4000 system. In the circuit evaluation, the output noise due to the clock switching phenomena, the gate signal feedthrough and the charge relaxation, was considered to be the critical problem. The most promising design for minimizing this problem had a CMOS current steering circuit at the input of a high CMRR operational amplifier. Simulation and test results showed that a modified capacitive transimpedance amplifier (CTIA) could subtract dark current output and reduce the output signal due to any difference between the frequencies of the optical input modulation signal and the switch modulation signal. In conclusion, the correlated readout circuit was shown to be a promising approach for advancing FPA technology.

  8. The focal plane assembly for the Athena X-ray Integral Field Unit instrument

    NASA Astrophysics Data System (ADS)

    Jackson, B. D.; van Weers, H.; van der Kuur, J.; den Hartog, R.; Akamatsu, H.; Argan, A.; Bandler, S. R.; Barbera, M.; Barret, D.; Bruijn, M. P.; Chervenak, J. A.; Dercksen, J.; Gatti, F.; Gottardi, L.; Haas, D.; den Herder, J.-W.; Kilbourne, C. A.; Kiviranta, M.; Lam-Trong, T.; van Leeuwen, B.-J.; Macculi, C.; Piro, L.; Smith, S. J.

    2016-07-01

    This paper summarizes a preliminary design concept for the focal plane assembly of the X-ray Integral Field Unit on the Athena spacecraft, an imaging microcalorimeter that will enable high spectral resolution imaging and point-source spectroscopy. The instrument's sensor array will be a 3840-pixel transition edge sensor (TES) microcalorimeter array, with a frequency domain multiplexed SQUID readout system allowing this large-format sensor array to be operated within the thermal constraints of the instrument's cryogenic system. A second TES detector will be operated in close proximity to the sensor array to detect cosmic rays and secondary particles passing through the sensor array for off-line coincidence detection to identify and reject events caused by the in-orbit high-energy particle background. The detectors, operating at 55 mK, or less, will be thermally isolated from the instrument cryostat's 2 K stage, while shielding and filtering within the FPA will allow the instrument's sensitive sensor array to be operated in the expected environment during both on-ground testing and in-flight operation, including straylight from the cryostat environment, low-energy photons entering through the X-ray aperture, low-frequency magnetic fields, and high-frequency electric fields.

  9. 320 x 256 Complementary Barrier Infrared Detector Focal Plane Array for Long-Wave Infrared Imaging

    NASA Technical Reports Server (NTRS)

    Nguyen, Jean; Rafol, Sir B.; Soibel, Alexander; Khoskhlagh, Arezou; Ting, David Z.-Y.; Liu, John K.; Mumolo, Jason M.; Gunapala, Sarath D.

    2012-01-01

    A 320 x 256 Complementary Barrier Infrared (CBIRD) focal plane array for long-wavelength infrared (LWIR) imaging is reported. The arrays were grown by molecular beam expitaxy (MBE) with a 300 period 1.9 um thick absorber. The mean dark current density of 2.2 x 10-4 A/cm2 was measured at an operating bias of 128 mV with a long wavelength cutoff of 8.8 ?m observed at 50% of the peak. The maximum quantum efficiency was 54% measured at 5.6 ?m. Operating at T = 80K, the array yielded an 81% fill factor with 97% operability. Good imagery with a mean noise equivalent different temperature (NE?T) of 18.6 mK and a mean detectivity of D* = 1.3 x 1011 cm-Hz1/2/W was achieved. The substrate was thinned using mechanical lapping and neither an AR coating nor a passivation layer was applied. This article provides the details of the fabrication process for achieving low-dark current LWIR CBIRD arrays. Discussion for an effective hard mask for excellent pattern transfer is given and appropriate mounting techniques for good thermal contact during the dry etching process is described. The challenges and differences between etching large 200 ?m test diodes and small 28 ?m FPA pixels are given.

  10. Micromachined room-temperature microbolometer for millimeter-wave detection and focal-plane imaging arrays

    NASA Astrophysics Data System (ADS)

    Rahman, Arifur; Duerr, Erik K.; de Lange, Gert; Hu, Qing

    1997-06-01

    We have combined silicon micromachining technology with planar circuits to fabricated room-temperature niobium microbolometers for millimeter-wave detection. In this type of detector, a thin niobium film, with a dimension much smaller than the wavelength, is fabricated on a 1-micrometers thick Si3N4 membrane of square and cross geometries. The Nb film acts both as a radiation absorber and temperature sensor. Incident radiation is coupled into the microbolometer by a 0.37 (lambda) dipole antenna with a center frequency of 95 GHz and a 3-db bandwidth of 15%, which is impedance matched with the Nb film. The dipole antennas is placed inside a micromachined pyramidal cavity formed by anisotropically etched Si wafers. To increase the Gaussian beam coupling efficiency, a machined square or circular horn is placed in front of the micromachined section. Circular horns interface more easily with die-based manufacturing processes; therefore, we have developed simulation tools that allow us to model circular machined horns. We have fabricated both single element receivers and 3 X 3 focal-plane arrays using uncooled Nb microbolometers. An electrical NEP level of 8.3 X 10-11 W/(root)Hz has been achieved for a single- element receiver. This NEP level is better than that of the commercial room-temperature pyroelectric millimeter-wave detectors. The frequency response of the microbolometer has a ln(1/f) dependence with frequency, and the roll-off frequency is approximately 35 kHz.

  11. Evolution of miniature detectors and focal plane arrays for infrared sensors

    NASA Astrophysics Data System (ADS)

    Watts, Louis A.

    1993-06-01

    Sensors that are sensitive in the infrared spectral region have been under continuous development since the WW2 era. A quest for the military advantage of 'seeing in the dark' has pushed thermal imaging technology toward high spatial and temporal resolution for night vision equipment, fire control, search track, and seeker 'homing' guidance sensing devices. Similarly, scientific applications have pushed spectral resolution for chemical analysis, remote sensing of earth resources, and astronomical exploration applications. As a result of these developments, focal plane arrays (FPA) are now available with sufficient sensitivity for both high spatial and narrow bandwidth spectral resolution imaging over large fields of view. Such devices combined with emerging opto-electronic developments in integrated FPA data processing techniques can yield miniature sensors capable of imaging reflected sunlight in the near IR and emitted thermal energy in the Mid-wave (MWIR) and longwave (LWIR) IR spectral regions. Robotic space sensors equipped with advanced versions of these FPA's will provide high resolution 'pictures' of their surroundings, perform remote analysis of solid, liquid, and gas matter, or selectively look for 'signatures' of specific objects. Evolutionary trends and projections of future low power micro detector FPA developments for day/night operation or use in adverse viewing conditions are presented in the following test.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. A novel design of infrared focal plane array with digital read out interface

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoyang; Ding, Ruijun; Lu, Wei; Zhou, Chun

    2010-10-01

    Infrared focal plane array (IRFPA) with digital read out interface is a key sign of the third generation IRFPA, which plays an important role in the reliability and miniaturization of infrared systems. A readout integrated circuit (ROIC) of IRFPA with digital readout interface based on dual ramp single slope (DRSS) analog to digital converter (ADC) architecture is presented in the paper. The design is realized using shared ADCs in column-wise and these ADCs are consisted of simplified DRSS architecture and shared units. Sample, conversion and readout are proceeded simultaneously in order to adapt large scale and high readout frame rate application. This circuit also shows many advantages, including small area and low power consumption. Simulation result shows that this architecture can be expand to 320×256 pixel array with a frame rate of 100 frames per second or a larger size whit lower frame rate, the quantized resolution of this circuit is 12 bit, and the analog power consumption is only 17μw per ADC.

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

    PubMed

    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.

  15. Mechanical design of mounts for IGRINS focal plane arrays and field flattening lenses

    NASA Astrophysics Data System (ADS)

    Oh, Jae Sok; Park, Chan; Cha, Sang-Mok; Yuk, In-Soo; Kim, Kang-Min; Chun, Moo-Young; Ko, Kyeongyeon; Oh, Heeyeong; Jeong, Ueejeong; Nah, Jakyoung; Lee, Hanshin; Pavel, Michael; Jaffe, Daniel T.

    2014-07-01

    IGRINS, the Immersion GRating INfrared Spectrometer, is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG focal plane array (FPA) detectors. The mechanical mounts for these detectors and for the final (field-flattening) lens in the optical train serve a critical function in the overall instrument design: Optically, they permit the only positional compensation in the otherwise "build to print" design. Thermally, they permit setting and control of the detector operating temperature independently of the cryostat bench. We present the design and fabrication of the mechanical mount as a single module. The detector mount includes the array housing, housing for the SIDECAR ASIC, a field flattener lens holder, and a support base. The detector and ASIC housing will be kept at 65 K and the support base at 130 K. G10 supports thermally isolate the detector and ASIC housing from the support base. The field flattening lens holder attaches directly to the FPA array housing and holds the lens with a six-point kinematic mount. Fine adjustment features permit changes in axial position and in yaw and pitch angles. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the computer simulation, the designed detector mount meets the optical and thermal requirements very well.

  16. The nonuniformity measurement and image processing algorithm evaluation for uncooled microbolometer infrared focal plane arrays

    NASA Astrophysics Data System (ADS)

    Qian, Yunsheng; Chang, BenKang; Zhang, Junju; Xing, Suxia; Yu, Shuizhong; Yang, Ji

    2005-01-01

    The great achievements were achieved in the manufacturing of uncooled microbolometer infrared focal plane arrays(UFPA). By this technique infrared system can be made in the formation of small volume, light weight, low price and being portable. It promotes greatly the utilization of infrared system in many fields. The main disadvantage of UFPA is non-uniformity. Despite non-uniformity of UFPA has been greatly improved, non-uniformity still restricts the performance of uncooled infrared system. In this paper, the attention is focused on the technology and methods measuring the non-uniformity of UFPA. The system that can measure the non-uniformity of UFPA and evaluate the image processing algorithms is developed. The measurement system consists of blackbody, infrared optics, control units, processing circuit, high-speed A/D converter, computer and software. To obtain the output signals of UFPA, the drive circuit and control circuit of thermoelectric stabilizer(TEC) of UFPA are developed. In the drive circuit, the CPLD device is employed to insure a small size circuit. In the TEC circuit, a kind of highly integrated and cost-effective, high-effiency, switch-mode driver is used to insure temperature stability of 0.01°C. The system is used to measure non-uniformity of microbolometer detectors which are produced by ULIS company. It can also present the evaluation of algorithm. The results are given and analyzed.

  17. Modeling of HgCdTe focal plane array spectral inhomogeneities

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    Infrared focal plane arrays (IRFPA) are widely used to perform high quality measurements such as spectrum acquisition at high rate, ballistic missile defense, gas detection, and hyperspectral imaging. For these applications, the fixed pattern noise represents one of the major limiting factors of the array performance. This sensor imperfection refers to the nonuniformity between pixels, and is partially caused by disparities of the cut-off wavenumbers. In this work, we focus particularly on mercury cadmium telluride (HgCdTe), which is the most important material of IR cooled detector applications. Among the many advantages of this ternary alloy is the tunability of the bandgap energy with Cadmium composition, as well as the high quantum efficiency. In order to predict and understand spectral inhomogeneities of HgCdTe-based IRFPA, we propose a modeling approach based on the description of optical phenomena inside the pixels. The model considers the p-n junctions as a unique absorbent bulk layer, and derives the sensitivity of the global structure to both Cadmium composition and HgCdTe layer thickness. For this purpose, HgCdTe optical and material properties were necessary to be known at low temperature (80K), in our operating conditions. We therefore achieved the calculation of the real part of the refractive index using subtracti

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

    NASA Astrophysics Data System (ADS)

    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. CCD TV focal plane guider development and comparison to SIRTF applications

    NASA Technical Reports Server (NTRS)

    Rank, David M.

    1989-01-01

    It is expected that the SIRTF payload will use a CCD TV focal plane fine guidance sensor to provide acquisition of sources and tracking stability of the telescope. Work has been done to develop CCD TV cameras and guiders at Lick Observatory for several years and have produced state of the art CCD TV systems for internal use. NASA decided to provide additional support so that the limits of this technology could be established and a comparison between SIRTF requirements and practical systems could be put on a more quantitative basis. The results of work carried out at Lick Observatory which was designed to characterize present CCD autoguiding technology and relate it to SIRTF applications is presented. Two different design types of CCD cameras were constructed using virtual phase and burred channel CCD sensors. A simple autoguider was built and used on the KAO, Mt. Lemon and Mt. Hamilton telescopes. A video image processing system was also constructed in order to characterize the performance of the auto guider and CCD cameras.

  20. Solid-state Image Sensor with Focal-plane Digital Photon-counting Pixel Array

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.; Pain, Bedabrata

    1997-01-01

    A solid-state focal-plane imaging system comprises an NxN array of high gain. low-noise unit cells. each unit cell being connected to a different one of photovoltaic detector diodes, one for each unit cell, interspersed in the array for ultra low level image detection and a plurality of digital counters coupled to the outputs of the unit cell by a multiplexer(either a separate counter for each unit cell or a row of N of counters time shared with N rows of digital counters). Each unit cell includes two self-biasing cascode amplifiers in cascade for a high charge-to-voltage conversion gain (greater than 1mV/e(-)) and an electronic switch to reset input capacitance to a reference potential in order to be able to discriminate detection of an incident photon by the photoelectron (e(-))generated in the detector diode at the input of the first cascode amplifier in order to count incident photons individually in a digital counter connected to the output of the second cascade amplifier. Reseting the input capacitance and initiating self-biasing of the amplifiers occurs every clock cycle of an integratng period to enable ultralow light level image detection by the may of photovoltaic detector diodes under such ultralow light level conditions that the photon flux will statistically provide only a single photon at a time incident on anyone detector diode during any clock cycle.

  1. Performance of Hg1‑xCdxTe infrared focal plane array at elevated temperature

    NASA Astrophysics Data System (ADS)

    Singh, Anand; Pal, Ravinder

    2017-04-01

    The simulated optical and electrical performance of the infrared HgCdTe focal plane array (FPA) for elevated operation temperature is reported. The depleted absorber layer is explored for equilibrium mode of operation up to 160 K. A resonant cavity is created to improve photon-matter interaction and hence, reduces the required absorption volume. The volume of the active region of HgCdTe detector is reduced by 70% in this manner. Dark current density is decreased without compromising the quantum efficiency. The effect of the reduced band filling effect leading to higher absorption coefficient and more efficient utilization of incident flux is employed. High quantum efficiency is achieved in a thin compositionally graded n+/ν/π/p HgCdTe photo-diode. This architecture helps to minimize the requirement of charge handling capacity in the CMOS read-out integrated circuit (ROIC) as the operation temperature is increased. Quantum efficiency ∼30% or above is shown to be sufficient for Noise Equivalent Temperature Difference (NETD) less than 20 mK with the reported design.

  2. Automated optical testing of LWIR objective lenses using focal plane array sensors

    NASA Astrophysics Data System (ADS)

    Winters, Daniel; Erichsen, Patrik; Domagalski, Christian; Peter, Frank; Heinisch, Josef; Dumitrescu, Eugen

    2012-10-01

    The image quality of today's state-of-the-art IR objective lenses is constantly improving while at the same time the market for thermography and vision grows strongly. Because of increasing demands on the quality of IR optics and increasing production volumes, the standards for image quality testing increase and tests need to be performed in shorter time. Most high-precision MTF testing equipment for the IR spectral bands in use today relies on the scanning slit method that scans a 1D detector over a pattern in the image generated by the lens under test, followed by image analysis to extract performance parameters. The disadvantages of this approach are that it is relatively slow, it requires highly trained operators for aligning the sample and the number of parameters that can be extracted is limited. In this paper we present lessons learned from the R and D process on using focal plane array (FPA) sensors for testing of long-wave IR (LWIR, 8-12 m) optics. Factors that need to be taken into account when switching from scanning slit to FPAs are e.g.: the thermal background from the environment, the low scene contrast in the LWIR, the need for advanced image processing algorithms to pre-process camera images for analysis and camera artifacts. Finally, we discuss 2 measurement systems for LWIR lens characterization that we recently developed with different target applications: 1) A fully automated system suitable for production testing and metrology that uses uncooled microbolometer cameras to automatically measure MTF (on-axis and at several o-axis positions) and parameters like EFL, FFL, autofocus curves, image plane tilt, etc. for LWIR objectives with an EFL between 1 and 12mm. The measurement cycle time for one sample is typically between 6 and 8s. 2) A high-precision research-grade system using again an uncooled LWIR camera as detector, that is very simple to align and operate. A wide range of lens parameters (MTF, EFL, astigmatism, distortion, etc.) can be

  3. High temperature operation In1-xAlxSb infrared focal plane

    NASA Astrophysics Data System (ADS)

    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.

  4. 480 x 8 hybrid HgCdTe infrared focal plane arrays

    NASA Astrophysics Data System (ADS)

    Kobayashi, Masako; Wada, Hideo; Okamura, Toshihiro; Kudo, Jun-ichi; Tanikawa, Kunihiro; Hikida, Soichiro; Miyamoto, Yoshihiro; Miyazaki, Shinji; Yoshida, Yukihiro

    2001-10-01

    This paper explains the technologies used for high-performance long linear arrays based on HgCdTe/CMOS hybrid multiplexers with bidirectional Time Delay and Integration (TDI) functions, and it describes the development of the first high-resolution Forward Looking Infrared (FLIR) system with the SXGA format. Long-wavelength Infrared (LWIR) photodiode arrays are fabricated using liquid-phase epitaxially grown HgCdTe on a CdZnTe substrate. Each photodiode array consists of 480x8-element n+/n-on-p diodes formed by B+ implantation. Each photodiode is surrounded by a crosswise drain diode to define the detection area. The diodes with a 10.3-μm cutoff wavelength had a typical zero-bias resistance of 10 MΩ and a shunt resistance of 1 GΩ. Four CMOS Read Out Integrated Circuits (ROICs) were used for bidirectional TDI and multiplex operations where each ROIC summed up and multiplexed eight signals from 120 channels. The ROIC also includes pixel deselection and gain control circuits along with the corresponding memory and writing means. The Infrared Focal Plane Arrays (IRFPAs) had a typical Noise Equivalent Temperature Difference (NETD) of 18 mK after TDI with F/1.55 optics and 10-μs integration. The FLIR system using the 480x8 IRFPA demonstrated a high spatial resolution of 1280 horizontal lines by 960 vertical lines (SXGA format) and NETD of less than 30 mK. The unique algorithm for image enhancement was successfully confirmed to be efficient.

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

    NASA Astrophysics Data System (ADS)

    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

  6. High performance type II superlattice focal plane array with 6μm cutoff wavelength

    NASA Astrophysics Data System (ADS)

    Miura, Kouhei; Machinaga, Ken-ichi; Balasekaran, Sundararajan; Kawahara, Takahiko; Migita, Masaki; Inada, Hiroshi; Iguchi, Yasuhiro; Sakai, Michito; Murooka, Junpei; Katayama, Haruyoshi; Kimata, Masafumi

    2016-05-01

    The cutoff wavelength of 6μm is preferable for the full usage of the atmospheric window in the mid-wavelength region. An InAs/GaSb type-II superlattice (T2SL) is the only known infrared material that has a theoretically predicted high performance and also the cutoff wavelength can be easily controlled by changing the thickness of InAs and GaSb. In this study, we used a p-i-n structure with InAs/GaSb T2SL absorber and also barrier layers which was grown on a Tedoped GaSb substrate by molecular beam epitaxy. A mesa-type focal plane array (FPA) with 320×256 pixels and 30μm pixel pitch was fabricated. Mesa structures were formed by inductively coupled plasma reactive ion etching with halogen gas mixture. Prior to the deposition of the SiO2 passivation film, N2 plasma treatment was applied for reducing the dark currents. Measured dark current of the sensor was 4x10-7A/cm2 at temperature of 77K and reverse bias of -20mV. The quantum efficiency was 0.35 and the detectivity was 4.1x1012cm/Hz1/2W. The sensor array was hybridized with the commercially available readout integrated circuit using indium bumps. The noise equivalent differential temperature measured with F/2.3 optics was 31mK at 77K. The operability was over 99%. This FPA is suitable for full usage of the atmospheric window in the mid-wavelength region.

  7. Hemispherical curved monolithic cooled and uncooled infrared focal plane arrays for compact cameras

    NASA Astrophysics Data System (ADS)

    Tekaya, Kevin; Fendler, Manuel; Dumas, Delphine; Inal, Karim; Massoni, Elisabeth; Gaeremynck, Yann; Druart, Guillaume; Henry, David

    2014-06-01

    InfraRed (IR) sensor systems like night vision goggles, missile approach warning systems and telescopes have an increasing interest in decreasing their size and weight. At the same time optical aberrations are always more difficult to optimize with larger Focal Plane Arrays (FPAs) and larger field of view. Both challenges can now take advantage of a new optical parameter thanks to flexible microelectronics technologies: the FPA spherical curvature. This bio-inspired approach can correct optical aberrations and reduce the number of lenses in camera conception. Firstly, a new process to curve thin monolithic devices has been applied to uncooled microbolometers FPAs. A functional 256×320 25μm pitch (roughly 1cm2) uncooled FPA has been thinned and curved. Its electrical response showed no degradation after our process (variation of less than 2.3% on the response). Then a two lenses camera with a curved FPA is designed and characterized in comparison with a two lenses camera with a flat FPA. Their Modulation Transfer Functions (MTFs) show clearly an improvement in terms of beams dispersion. Secondly, a new process to fabricate monolithic cooled flip-chip MCT-IRCMOS FPAs was developed leading to the first spherical cooled IR FPA: with a radius of 550 mm. Other radii are achieved. A standard opto-electrical characterization at 80 K of the imager shows no additional short circuit and no mean response alteration compared to a standard IRCMOS shown in reference. Noise is also studied with a black body between 20 and 30°C.

  8. Two-dimensional focal plane detector arrays for LWIR/VLWIR space and airborne sounding missions

    NASA Astrophysics Data System (ADS)

    Hanna, S.; Bauer, A.; Bitterlich, H.; Bruder, M.; Haas, L.-D.; Haiml, M.; Hofmann, K.; Mahlein, K.-M.; Nothaft, H.-P.; Schallenberg, T.; Weber, A.; Wendler, J.; Wollrab, R.; Ziegler, J.

    2010-10-01

    An increasing need for high-precision atmospheric data especially in the long wavelength infrared (LWIR) and very long wavelength infrared (VLWIR) spectral ranges has arisen in the past years not only for the analysis of climate change and its effect on the earth's ecosystem, but also for weather forecast and atmospheric monitoring purposes. Spatially and spectrally resolved atmospheric emission data are advantageously gathered through limb or nadir sounding using an imaging Fourier transform (FT) interferometer with a two-dimensional (2D) high-speed focal plane detector array (FPA). In this paper, AIM reports on its latest results on MCT VLWIR FPAs for Fourier transform infrared sounding applications in the 8-15μm spectral range. The performance of a (112x112) pixel photodiode array with a 40μm pixel pitch incorporating extrinsic p-doping for low dark current, a technique for linearity improvement at high photon fluxes, pixel guards, pixel select/de-select, and a (2x2) super-pixel architecture is discussed. The customized read-out integrated circuit (ROIC) supporting integrate while-read (IWR) operation has a buffered direct injection (BDI) input stage and a full well capacity (FWC) of 143 Megaelectrons per super-pixel. It consists of two independently operating halves with two analog video outputs each. The full frame rate is typically 4k frames/sec, making it suitable for use with rapid scan FT infrared spectrometers. At a 55K operating temperature and an ~14.4μm cut-off wavelength, a photo response of 12.1mV/K and a noise equivalent temperature difference of 24.8mK at half well filling are demonstrated for a 286K reference scene. The nonlinearity error is <0.5%.

  9. Correction of NIRI/ Altair non-common path aberrations using focal plane sharpening

    NASA Astrophysics Data System (ADS)

    Ball, Jesse G.; Lai, Olivier; Trujillo, Chadwick; White, John

    2016-07-01

    Non-common path aberrations (NCPA), in an adaptive optics system, are static aberrations induced by the science and wavefront sensor's (WFS) separate light paths, for which the latter is corrected (although not present in the former), and the former is not. It was suspected1 that this type of aberration may significantly affect the image quality performance of Altair + NIRI, the Gemini North Observatory's adaptive optics facility instrument and the near-infrared imaging camera. A simple and effective focal plane sharpening technique was developed to optimize these static aberrations for Altair & NIRI at f/32, and 2.12μm. By varying the shape of the deformable mirror (DM) to introduce Zernike aberration coefficients through a reasonable range of values, the images produced were read out on the NIRI detector and analyzed for Strehl ratio. Fitting a second-order polynomial to this data set gave an optimized value for each coefficient out to Z49. The Strehl ratio was improved by 6% +/- 2% and the Z5 (45° astigmatism) term showed the only appreciable error contribution to the current NCPA offset of 0.15μm in k-prime (2.12μm). Aside from resulting in a slight improvement in image quality, the technique developed is non-invasive and will be implemented in other instruments and cameras that typically couple with Altair and have outdated or erroneous NCPA files currently. Furthermore, some high spatial-frequency structure in the PSF was found that limited the effect of these corrections, and may be a key component in further investigations towards image quality degradation in Altair + NIRI.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Development of high performance SWIR InGaAs focal plane array

    NASA Astrophysics Data System (ADS)

    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

  15. Enchanced interference cancellation and telemetry reception in multipath environments with a single paraboic dish antenna using a focal plane array

    NASA Technical Reports Server (NTRS)

    Mukai, Ryan (Inventor); Vilnrotter, Victor A. (Inventor)

    2011-01-01

    An Advanced Focal Plane Array ("AFPA") for parabolic dish antennas that exploits spatial diversity to achieve better channel equalization performance in the presence of multipath (better than temporal equalization alone), and which is capable of receiving from two or more sources within a field-of-view in the presence of multipath. The AFPA uses a focal plane array of receiving elements plus a spatio-temporal filter that keeps information on the adaptive FIR filter weights, relative amplitudes and phases of the incoming signals, and which employs an Interference Cancelling Constant Modulus Algorithm (IC-CMA) that resolves multiple telemetry streams simultaneously from the respective aero-nautical platforms. This data is sent to an angle estimator to calculate the target's angular position, and then on to Kalman filters FOR smoothing and time series prediction. The resulting velocity and acceleration estimates from the time series data are sent to an antenna control unit (ACU) to be used for pointing control.

  16. 1024 x 1024 pixel mid-wavelength and long-wavelength infrared QWIP focal plane arrays for imaging applications

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Hill, C. J.; Rafol, S. B.; Mumolo, J. M.; Trinh, J. T.; Tidrow, M. Z.; LeVan, P. D.

    2005-01-01

    Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 10(24) x 10(24) pixel quantum well infrared photodetector (QWIP) focal planes have been demonstrated with excellent imaging performance. The MWIR QWIP detector array has demonstrated a noise equivalent differential temperature (NEAT) of 17 mK at a 95 K operating temperature with f/2.5 optics at 300 K background and the LWIR detector array has demonstrated a NEAT of 13 mK at a 70 K operating temperature with the same optical and background conditions as the MWIR detector array after the subtraction of system noise. Both MWIR and LWIR focal planes have shown background limited performance (BLIP) at 90 K and 70 K operating temperatures respectively, with similar optical and background conditions. In this paper, we will discuss the performance in terms of quantum efficiency, NE(delta)T, uniformity, operability and modulation transfer functions.

  17. Simultaneous imaging of multiple focal planes for three-dimensional microscopy using ultra-high-speed adaptive optics.

    PubMed

    Duocastella, Martí; Sun, Bo; Arnold, Craig B

    2012-05-01

    Traditional white-light and fluorescent imaging techniques provide powerful methods to extract high-resolution information from two-dimensional (2-D) sections, but to retrieve information from a three-dimensional (3-D) volume they require relatively slow scanning methods that result in increased acquisition time. Using an ultra-high speed liquid lens, we circumvent this problem by simultaneously acquiring images from multiple focal planes. We demonstrate this method by imaging microparticles and cells flowing in 3-D microfluidic channels.

  18. A Simple Model for Predicting the Flux Distribution through the Focal Plane of a Multifaceted-Concentrator Solar Furnace.

    DTIC Science & Technology

    1984-12-06

    Concentrators ," Solar Energy Re- search Institute Report SERI/TR-631-336 (April 1980). 4. Jaffe, L.D., "Optimization of Dish Solar Collectors with and Without...NO. 5 A Simple Model for Predicting the Flux Distribution Through the Focal Plane of a Multifaceted- Concentrator Solar Furnace by D.E.E. Carlson, R.B...Diver, and E.A. Fletcher Prepared for Publication In Journal of Solar Energy Engineering University of Minnesota Mechanical Engineering Department

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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 < 20 mK for short snapshot integration times of typically 2 ms. PtSi and QWIP modules are usually operated in a rolling frame integration mode with frame rates of 30 - 60 Hz and provide thermal resolutions of NETD < 80 mK for PtSi and NETD < 20 mK for QWIP, respectively. Due to the lower quantum efficiency compared to MCT, however, the integration time is typically chosen to be as long 10 - 20 ms. The heat load of the integrated detector cooler assemblies (IDCAs) could be reduced to an amount as low, that a 1 W split liner cooler provides sufficient cooling power to operate the modules -- including the QWIP with 60 K operation temperature -- at ambient temperatures up to 65 degrees Celsius. Miniaturized command/control electronics (CCE) available for all modules provide a standardized digital interface, with 14 bit analogue to digital conversion for state to the art correctability, access to highly dynamic scenes without any loss of information and simplified 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

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

    NASA Astrophysics Data System (ADS)

    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

  3. Microbolometer Terahertz Focal Plane Array and Camera with Improved Sensitivity in the Sub-Terahertz Region

    NASA Astrophysics Data System (ADS)

    Oda, Naoki; Kurashina, Seiji; Miyoshi, Masaru; Doi, Kohei; Ishi, Tsutomu; Sudou, Takayuki; Morimoto, Takao; Goto, Hideki; Sasaki, Tokuhito

    2015-10-01

    A pixel in an uncooled microbolometer terahertz (THz) focal plane array (FPA) has a suspended structure above read-out integrated circuit (ROIC) substrate. An optical cavity structure is formed between a thin metallic layer deposited on the suspended structure and a thick metallic layer deposited on the ROIC surface. The geometrical optical cavity length for our previous pixel structure, 3-4 μm, is extended three times, so that responsivity can be increased in the sub-THz region. This modification is carried out by depositing a thick SiN layer on the thick metallic layer. The modified pixel structure is applied to 640 × 480 and 320 × 240 THz-FPAs with 23.5 μm pixel pitch. Minimum detectable powers per pixel (MDP) are evaluated for these FPAs at 4.3, 2.5, 0.6, and 0.5 THz, and the MDP values are found to be improved by a factor of ten at 0.6 and 0.5 THz. The MDP values of the THz-FPAs developed in this work are compared with those of other THz detectors, such as uncooled antenna-coupled CMOS (complimentary metal-oxide semiconductor) THz-FPAs and cooled bolometer arrays. It is found that our THz-FPAs are more sensitive in the sub-THz region than the CMOS THz-FPAs, while they are much less sensitive than the cooled bolometer arrays. These THz-FPAs are incorporated into a 640 × 480 THz camera and 320 × 240 THz camera, and imaging equipment is developed. The equipment consists of a linearly polarized sub-THz source, a collimator lens, a beam homogenizer, two wire grids, a quarter-wave plate, and two THz cameras, and sub-THz images are demonstrated. It should be mentioned for the equipment that imaging of transmission and reflection is realized by moving only the quarter-wave plate, and the reflection image is taken along a direction normal to a sample surface so that the reflection image is hardly deformed.

  4. Starch-based second-harmonic-generated collinear frequency-resolved optical gating pulse characterization at the focal plane of a high-numerical-aperture lens.

    PubMed

    Amat-Roldán, Ivan; Cormack, Iain G; Loza-Alvarez, Pablo; Artigas, David

    2004-10-01

    We report the use of starch as an ideal nonlinear medium with which to perform collinear frequency-resolved optical gating measurements of ultrashort pulses at the focal plane of a high-numerical-aperture (NA) lens. We achieved these measurements by simply sandwiching starch granules (suspended in water) between two coverslips and placing them within the focal plane of a high-NA lens. The natural nonlinear characteristics of starch allow the correct phase matching of pulses at the focal plane of a high-NA lens at different wavelengths. This elegant arrangement overcomes all the complexity and problems that were previously associated with pulse characterization within a multiphoton microscope.

  5. Quasi-plane shear wave propagation induced by acoustic radiation force with a focal line region: a simulation study.

    PubMed

    Guo, Min; Abbott, Derek; Lu, Minhua; Liu, Huafeng

    2016-03-01

    Shear wave propagation speed has been regarded as an attractive indicator for quantitatively measuring the intrinsic mechanical properties of soft tissues. While most existing techniques use acoustic radiation force (ARF) excitation with focal spot region based on linear array transducers, we try to employ a special ARF with a focal line region and apply it to viscoelastic materials to create shear waves. First, a two-dimensional capacitive micromachined ultrasonic transducer with 64 × 128 fully controllable elements is realised and simulated to generate this special ARF. Then three-dimensional finite element models are developed to simulate the resulting shear wave propagation through tissue phantom materials. Three different phantoms are explored in our simulation study using: (a) an isotropic viscoelastic medium, (b) within a cylindrical inclusion, and (c) a transverse isotropic viscoelastic medium. For each phantom, the ARF creates a quasi-plane shear wave which has a preferential propagation direction perpendicular to the focal line excitation. The propagation of the quasi-plane shear wave is investigated and then used to reconstruct shear moduli sequentially after the estimation of shear wave speed. In the phantom with a transverse isotropic viscoelastic medium, the anisotropy results in maximum speed parallel to the fiber direction and minimum speed perpendicular to the fiber direction. The simulation results show that the line excitation extends the displacement field to obtain a large imaging field in comparison with spot excitation, and demonstrate its potential usage in measuring the mechanical properties of anisotropic tissues.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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.

  8. HgCdTe p-on- n Focal-Plane Array Fabrication Using Arsenic Incorporation During MBE Growth

    NASA Astrophysics Data System (ADS)

    Gravrand, O.; Ballet, Ph.; Baylet, J.; Baier, N.

    2009-08-01

    Extrinsic p-type doping during molecular-beam epitaxy (MBE) growth represents an essential generic toolbox for advanced heterostructures based on the HgCdTe material system: PiN diodes, mesa avalanche photodiodes (APD) or third-generation multispectral focal-plane arrays. Today, arsenic appears to be the best candidate to fulfill this role and our group is actively working on its incorporation during MBE growth, using an original radio frequency (RF) plasma source for arsenic. Such a cell is supposed to deliver a monatomic As flux, and as expected we observed high As electrical activation rates after annealing short-wave (SW), mid-wave (MW), and long-wave (LW) layers. At last, a couple of technological runs have been carried out in the MW range in order to validate the approach on practical devices. p-on- n focal-plane arrays (FPA) have been fabricated using a mesa delineated technology on an As-on-In doped metallurgical heterojunction layer grown on a lattice-matched CdZnTe layer (320 × 256, 30 μm pitch, 5 μm cutoff at 77 K). Observed diodes exhibit very interesting electro-optical characteristics: large shunt impedance, high quantum efficiency, and no noticeable excess noise. The resulting focal-plane arrays were observed to be very uniform, leading to high operabilities. Noise equivalent temperature difference (NETD) distributions are very similar to those observed with the As ion-implanted p-on- n technology, fabricated in our laboratory as well. In our opinion, those excellent results demonstrate the feasibility of our MBE in situ arsenic doping process. Good electrical activation rates and high-quality layers can be obtained. We believe that such an approach allows precise control of the p-doping profile in the HgCdTe layer, which is necessary for advanced structure designs.

  9. Infrared hyperspectral imaging using a broadly tunable external cavity quantum cascade laser and microbolometer focal plane array

    SciTech Connect

    Phillips, Mark C.; Ho, Nicolas

    2008-02-04

    A versatile mid-infrared hyperspectral imaging system is demonstrated by combining a broadly tunable external cavity quantum cascade laser and a microbolometer focal plane array. The tunable mid-infrared laser provided high brightness illumination over a tuning range from 985 cm-1 to 1075 cm-1 (9.30-10.15 μm). Hypercubes containing images at 300 wavelengths separated by 0.3 cm 1 were obtained in 12 s. High spectral resolution chemical imaging of methanol vapor was demonstrated for both static and dynamic systems. The system was also used to image and characterize multiple component liquid and solid samples.

  10. A K-band spectroscopic focal plane array for the Robert C. Byrd Green Bank radio telescope

    NASA Astrophysics Data System (ADS)

    Morgan, Matthew; White, Steve; Lockman, Jay; Bryerton, Eric; Saini, Kamaljeet; Norrod, Rorger; Simon, Bob; Srikanth, Sivasankaran; Anderson, Gary; Pisano, Daniel

    2008-08-01

    This paper presents the design and current status of a K-Band Focal Plane Array (KFPA) for the Green Bank Telescope (GBT). The prototype array will go online with 7 independent dual-polarized beams, but the design target is a fully-populated instrument with approximately 60 beams on the sky. This project presents a number of technical challenges, including the architecture of a cryostat capable of supporting 60 independent receivers, design of high- performance components that fit behind the aperture of a compact feedhorn, and stable transmission of the large-volume of receiver data from the telescope to a remote building for back-end processing.

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

    NASA Astrophysics Data System (ADS)

    Hagemann, M.; Bassini, R.; van den Berg, A. M.; Ellinghaus, F.; Frekers, D.; Hannen, V. M.; Häupke, T.; Heyse, J.; Jacobs, E.; Kirsch, M.; Krüsemann, B.; Rakers, S.; Sohlbach, H.; Wörtche, H. J.

    1999-11-01

    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°. 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.

  12. Spectroscopy of transfermium nuclei using the GABRIELA set up at the focal plane of the VASSILISSA recoil separator

    NASA Astrophysics Data System (ADS)

    Hauschild, K.; Lopez-Martens, A.; Dorvaux, O.; Piot, J.; Curien, D.; Gall, B.; Yeremin, A. V.; Chelnokov, M. L.; Chepigin, V. I.; Isaev, A. V.; Izosimov, I. N.; Kabachenko, A. P.; Katrasev, D. E.; Kuznetsov, A. N.; Malyshev, O. N.; Popeko, A. G.; Sokol, E. A.; Svirikhin, A. I.; Wiborg-Hagen, T.; Nyhus, H. T.; Siem, S.; Drafta, G.; Pantelica, D.; Scintee, N.; Görgen, A.; Kutsarova, T.; Mullins, S.; Šáro, Š.

    2010-06-01

    An IN2P3-JINR collaboration has launched a project called GABRIELA at the Flerov Laboratory for Nuclear Reactions (FLNR) within the Joint Institute for Nuclear Research (JINR) in Dubna (Russia). The goal of the project is to perform gamma-ray and internal conversion electron spectroscopy of heavy nuclei produced in fusion-evaporation reactions and transported to the focal plane of the recoil separator VASSILISSA. During five experimental campaigns of GABRIELA, the detection system has gained in sensitivity and new spectroscopic information has been obtained for 249Fm, 251Fm, 253No and 255Lr. In this contribution new results for 253No will be discussed.

  13. Spectroscopy of transfermium nuclei using the GABRIELA set up at the focal plane of the VASSILISSA recoil separator

    NASA Astrophysics Data System (ADS)

    Hauschild, K.; Lopez-Martens, A.; Briançon, Ch.; Désesquelles, P.; Garcia-Santamaria, S.; Korichi, A.; Robin, J.; Dorvaux, O.; Piot, J.; Curien, D.; Gall, B.; Khalfallah, F.; Khouaja, A.; Rousseau, M.; Stuttgé, L.; Rowley, N.; Yeremin, A. V.; Belozerov, A. V.; Chelnokov, M. L.; Chepigin, V. I.; Gorshkov, V. A.; Isaev, A. V.; Izosimov, I. N.; Kabachenko, A. P.; Katrasev, D. E.; Kutznetzov, A. N.; Malyshev, O. N.; Popeko, A. G.; Sagaidak, R. N.; Shutov, A. V.; Sokol, E. A.; Svirikhin, A. I.; Wiborg-Hagen, T.; Guttormsen, M.; Larsen, A. C.; Nyhus, H. T.; Siem, S.; Syed, N. U. H.; Hanappe, F.; Bouchat, V.; Jones, P.; Borcea, R.; Drafta, G.; Pantelica, D.; Rotaru, F.; Scintee, N.; Zamfir, V.; Görgen, A.; Theisen, Ch.; Minkova, A.; Kutsarova, T.; Stodel, Ch.; Mullins, S.; Lieder, E.; Antalic, S.; Šáro, Š.; Venhart, M.

    2010-04-01

    An IN2P3-JINR collaboration has launched a project called GABRIELA at the Flerov Laboratory for Nuclear Reactions (FLNR) within the Joint Institute for Nuclear Research (JINR) in Dubna (Russia). The goal of the project is to perform gamma-ray and internal conversion electron spectroscopy of heavy nuclei produced in fusion-evaporation reactions and transported to the focal plane of the recoil separator VASSILISSA. During five experimental campaigns of GABRIELA, the detection system has gained in sensitivity and new spectroscopic information has been obtained for 249Fm, 251Fm, 253No and 255Lr.

  14. Results of ground tests and calibration of x-ray focal plane detectors for ART-XC/SRG instrument

    NASA Astrophysics Data System (ADS)

    Levin, Vasily; Pavlinsky, Mikhail; Akimov, Valery; Kuznetsova, Maria; Rotin, Alexey; Krivchenko, Aleksandr; Lapshov, Igor; Oleynikov, Vladimir

    2016-07-01

    The Russian Space Research Institute (IKI) has developed seven flight models and three spare models of the X-ray detectors for the ART-XC/SRG telescope. Each detector situated in the focal plane of ART-XC X-ray optics and includes CdTe die, front-end electronics, data processing, storage and telemetry units. In the Space Research Institute performed a vibration, thermal cycling and thermal vacuum tests of X-ray detectors. During this tests have been studied the leakage current stability, polarization rate, spectroscopic and imaging performance in the working temperature range. The current status of the X-ray detectors development and testing presented.

  15. Resolution and Mass Range Performance in Distance-of-Flight Mass Spectrometry with a Multichannel Focal-Plane Camera Detector

    SciTech Connect

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

    2011-10-05

    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 two, with typical DOF linewidths of 300 {micro}m (R(FWHM)=1000). Merits of solid-state detection for DOFMS are evaluated and methods to extend the DOFMS mass range are considered.

  16. Resolution and Mass Range Performance in Distance-of-flight Mass Spectrometry with a Multichannel Focal-Plane Camera Detector.

    SciTech Connect

    Graham, Alexander W.; 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.

  17. Microfabrication and Device Parameter Testing of the Focal Plane Arrays for the Spider and BICEP2/Keck CMB Polarimeters

    NASA Astrophysics Data System (ADS)

    Bonetti, J. A.; Turner, A. D.; Kenyon, M.; Orlando, A.; Brevik, J. A.; Trangsrud, A.; Sudiwala, R.; Leduc, H. G.; Nguyen, H. T.; Day, P. K.; Bock, J. J.; Golwala, S. R.; Sayers, J.; Kovac, J. M.; Lange, A. E.; Jones, W. C.; Kuo, C. L.

    2009-12-01

    Spider and BICEP2/Keck are projects to study the polarization of the cosmic microwave background (CMB). The focal planes for both require large format arrays of superconducting transition edge sensors (TES's). A major challenge for these projects is fabricating arrays with high uniformity in device parameters. A microfabrication process is described that meets this challenge. The results from device testing are discussed. Each focal plane is composed of 4 square wafers (tiles), and each wafer contains 128 membrane-isolated, polarization-sensitive, antenna-coupled TES's. After processing, selected wafers are pre-screened in a quick-turn-around, cryogen-free, 3He fridge. The pre-screening is performed with a commercial resistance bridge and measures transition temperatures (Tc) and normal state resistances (Rn). After pre-screening, 4 tiles at a time are fully characterized in a testbed employing a SQUID readout and SQUID mulitplexing. The tests demonstrate the values of Tc, Rn, thermal conductance, g, and the standard deviations of each, across a wafer and from wafer to wafer, are within design specifications.

  18. The WIYN one degree imager 2014: performance of the partially populated focal plane and instrument upgrade path

    NASA Astrophysics Data System (ADS)

    Harbeck, Daniel R.; Boroson, Todd; Lesser, Michael; Rajagopal, Jayadev; Yeatts, Andrey; Corson, Charles; Liu, Wilson; Dell'Antonio, Ian; Kotulla, Ralf; Ouellette, David; Hooper, Eric; Smith, Mike; Bredthauer, Richard; Martin, Pierre; Muller, Gary; Knezek, Patricia; Hunten, Mark

    2014-07-01

    The One Degree Imager (ODI) was deployed during the summer of 2012 at the WIYN 3.5m telescope, located on Kitt Peak near Tucson, AZ (USA). ODI is an optical imager designed to deliver atmosphere-limited image quality (≤ 0.4" FWHM) over a one degree field of view, and uses Orthogonal Transfer Array (OTA) detectors to also allow for on-chip tip/tilt image motion compensation. At this time, the focal plane is partially populated ("pODI") with 13 out of 64 OTA detectors, providing a central scientifically usable field of view of about 24' x 24'; four of the thirteen detectors are installed at outlying positions to probe image quality at all field angles. The image quality has been verified to be indeed better than 0.4'' FWHM over the full field when atmospheric conditions allow. Based on over one year of operations, we summarize pODIs performance and lessons learned. As pODI has proven the viability of the ODI instrument, the WIYN consortium is engaging in an upgrade project to add 12 more detectors to the focal plane enlarging the scientifically usable field of view to about 40' x 40'. A design change in the new detectors has successfully addressed a low light level charge transfer inefficiency.

  19. A method using focal plane analysis to determine the performance of reflector antennas

    NASA Technical Reports Server (NTRS)

    Cramer, P. W.; Imbriale, W. A.; Rengarajan, S. R.

    1995-01-01

    Reflector antenna optimization schemes using array feeds have been used to recover antenna losses resulting from antenna distortions and aberrations and to generate contour coverage patterns. Historically, these optimizations have been carried out using the antenna far-field scattered patterns. The far-field patterns must be calculated separately for each of the array feed elements. For large or complex antennas (which include beam-waveguide antennas), the far-field calculation times can be prohibitive. This article presents a method with which the optimization can be carried out in the antenna focal region, where the scattering calculation needs only to be done once independently of the number of the elements in the array. This article also includes the results of a study, utilizing this unique technique, to determine the capabilities and limitations of using array feeds to compensate for gravitational induced losses in large reflector antennas.

  20. The spectral archive of cosmic X-ray sources observed by the Einstein Observatory Focal Plane Crystal Spectrometer

    NASA Technical Reports Server (NTRS)

    Lum, Kenneth S. K.; Canizares, Claude R.; Clark, George W.; Coyne, Joan M.; Markert, Thomas H.; Saez, Pablo J.; Schattenburg, Mark L.; Winkler, P. F.

    1992-01-01

    The Einstein Observatory Focal Plane Crystal Spectrometer (FPCS) used the technique of Bragg spectroscopy to study cosmic X-ray sources in the 0.2-3 keV energy range. The high spectral resolving power (E/Delta-E is approximately equal to 100-1000) of this instrument allowed it to resolve closely spaced lines and study the structure of individual features in the spectra of 41 cosmic X-ray sources. An archival summary of the results is presented as a concise record the FPCS observations and a source of information for future analysis by the general astrophysics community. For each observation, the instrument configuration, background rate, X-ray flux or upper limit within the energy band observed, and spectral histograms are given. Examples of the contributions the FPCS observations have made to the understanding of the objects observed are discussed.

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

    PubMed Central

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

    2017-01-01

    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. PMID:28191819

  2. Coaxial Dual-wavelength Interferometric Method for a Thermal Infrared Focal-plane-array with Integrated Gratings

    NASA Astrophysics Data System (ADS)

    Shang, Yuanfang; Ye, Xiongying; Cao, Liangcai; Song, Pengfei; Feng, Jinyang

    2016-05-01

    Uncooled infrared (IR) focal-plane-array (FPA) with both large sensing range and high sensitivity is a great challenge due to the limited dynamic range of the detected signals. A coaxial dual-wavelength interferometric system was proposed here to detect thermal-induced displacements of an ultrasensitive FPA based on polyvinyl-chloride(PVC)/gold bimorph cantilevers and carbon nanotube (CNT)-based IR absorbing films. By alternately selecting the two displacement measurements performed by λ1 (=640 nm) and λ2 (=660 nm), the temperature measuring range with greater than 50% maximum sensitivity can be extended by eight-fold in comparison with the traditional single-wavelength mode. Meanwhile, the relative measurement error over the full measuring range is below 0.4%. In addition, it offers a feasible approach for on-line and on-wafer FPA characterization with great convenience and high efficiency.

  3. Spectroscopy of transfermium nuclei using the GABRIELA set up at the focal plane of the VASSILISSA recoil separator

    SciTech Connect

    Hauschild, K.; Lopez-Martens, A.; Dorvaux, O.; Piot, J.; Curien, D.; Gall, B.; Yeremin, A. V.; Chelnokov, M. L.; Chepigin, V. I.; Isaev, A. V.; Izosimov, I. N.; Kabachenko, A. P.; Katrasev, D. E.; Kuznetsov, A. N.; Malyshev, O. N.; Popeko, A. G.; Sokol, E. A.; Svirikhin, A. I.; Wiborg-Hagen, T.; Nyhus, H. T

    2010-06-01

    An IN2P3-JINR collaboration has launched a project called GABRIELA at the Flerov Laboratory for Nuclear Reactions (FLNR) within the Joint Institute for Nuclear Research (JINR) in Dubna (Russia). The goal of the project is to perform gamma-ray and internal conversion electron spectroscopy of heavy nuclei produced in fusion-evaporation reactions and transported to the focal plane of the recoil separator VASSILISSA. During five experimental campaigns of GABRIELA, the detection system has gained in sensitivity and new spectroscopic information has been obtained for {sup 249}Fm, {sup 251}Fm, {sup 253}No and {sup 255}Lr. In this contribution new results for {sup 253}No will be discussed.

  4. Solid state active/passive night vision imager using continuous-wave laser diodes and silicon focal plane arrays

    NASA Astrophysics Data System (ADS)

    Vollmerhausen, Richard H.

    2013-04-01

    Passive imaging offers covertness and low power, while active imaging provides longer range target acquisition without the need for natural or external illumination. This paper describes a focal plane array (FPA) concept that has the low noise needed for state-of-the-art passive imaging and the high-speed gating needed for active imaging. The FPA is used with highly efficient but low-peak-power laser diodes to create a night vision imager that has the size, weight, and power attributes suitable for man-portable applications. Video output is provided in both the active and passive modes. In addition, the active mode is Class 1 eye safe and is not visible to the naked eye or to night vision goggles.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. 640 x 512 Pixels Long-Wavelength Infrared (LWIR) Quantum-Dot Infrared Photodetector (QDIP) Imaging Focal Plane Array

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath D.; Bandara, Sumith V.; Hill, Cory J.; Ting, David Z.; Liu, John K.; Rafol, Sir B.; Blazejewski, Edward R.; Mumolo, Jason M.; Keo, Sam A.; Krishna, Sanjay; Chang, Y. -C.; Shott, Craig A.

    2007-01-01

    Epitaxially grown self-assembled. InAs-InGaAs-GaAs quantum dots (QDs) are exploited for the development of large-format long-wavelength infrared focal plane arrays (FPAs). The dot-in-a-well (DWELL) structures were experimentally shown to absorb both 45 degrees and normal incident light, therefore, a reflection grating structure was used to enhance the quantum efficiency. The devices exhibit peak responsivity out to 8.1 micrometers, with peak detectivity reaching approximately 1 X 10(exp 10) Jones at 77 K. The devices were fabricated into the first long-wavelength 640 x 512 pixel QD infrared photodetector imaging FPA, which has produced excellent infrared imagery with noise equivalent temperature difference of 40 mK at 60-K operating temperature.

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

    SciTech Connect

    Nisius, D.; Janssens, R.V.F.; Ahmad, I.

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

    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.

  10. Test results of Spacelab 2 infrared telescope focal plane. [photoconductive detector fabrication and JFET transimpedance amplifier design

    NASA Technical Reports Server (NTRS)

    Young, E. T.; Rieke, G. H.; Gautier, T. N.; Hoffmann, W. F.; Low, F. J.; Poteet, W.; Fazio, G. G.; Koch, D.; Traub, W. A.; Urban, E. W.

    1981-01-01

    The small helium cooled infrared telescope for Spacelab 2 is designed for sensitive mapping of extended, low-surface-brightness celestial sources as well as highly sensitive investigations of the shuttle contamination environment (FPA) for this mission is described as well as the design for a thermally isolated, self-heated J-FET transimpedance amplifier. This amplifier is Johnson noise limited for feedback resistances from less than 10 to the 8th power Omega to greater than 2 x 10 to the 10th power Omega at T = 4.2K. Work on the focal plane array is complete. Performance testing for qualification of the flight hardware is discussed, and results are presented. All infrared data channels are measured to be background limited by the expected level of zodiacal emission.

  11. A 160 x 120 pixel uncooled TEC-less infrared radiation focal plane array on a standard ceramic package

    NASA Astrophysics Data System (ADS)

    Funaki, Hideyuki; Honda, Hiroto; Fujiwara, Ikuo; Yagi, Hitoshi; Ishii, Kouichi; Sasaki, Keita

    2009-05-01

    We have developed a 32 μm pitch and 160 × 120 pixel uncooled infrared radiation focal plane array (IRFPA) on SOI by 0.35 μm CMOS technology and bulk-micromachining. For IR detection, we use silicon single crystal series p-n junctions which can realize high uniformity of temperature coefficient and low voltage drift. We have also developed a low-noise CMOS readout circuit on the same SOI which can calibrate the substrate temperature variation in every frame period, comparing two types of pixels, a bulk-micromachined infrared detection pixel and a non-micromachined reference pixel. Then the FPA requires no thermo-electric cooler (TEC) and is mounted on a low-cost standard ceramic package for the consumer products market.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Design and verification of focal plane assembly thermal control system of one space-based astronomy telescope

    NASA Astrophysics Data System (ADS)

    Yang, Wen-gang; Fan, Xue-wu; Wang, Chen-jie; Wang, Ying-hao; Feng, Liang-jie; Du, Yun-fei; Ren, Guo-rui; Wang, Wei; Li, Chuang; Gao, Wei

    2015-10-01

    One space-based astronomy telescope will observe astronomy objects whose brightness should be lower than 23th magnitude. To ensure the telescope performance, very low system noise requirements need extreme low CCD operating temperature (lower than -65°C). Because the satellite will be launched in a low earth orbit, inevitable space external heat fluxes will result in a high radiator sink temperature (higher than -65°C). Only passive measures can't meet the focal plane cooling specification and active cooling technologies must be utilized. Based on detailed analysis on thermal environment of the telescope and thermal characteristics of focal plane assembly (FPA), active cooling system which is based on thermo-electric cooler (TEC) and heat rejection system (HRS) which is based on flexible heat pipe and radiator have been designed. Power consumption of TECs is dependent on the heat pumped requirements and its hot side temperature. Heat rejection capability of HRS is mainly dependent on the radiator size and temperature. To compromise TEC power consumption and the radiator size requirement, thermal design of FPA must be optimized. Parasitic heat loads on the detector is minimized to reduce the heat pumped demands of TECs and its power consumption. Thermal resistance of heat rejection system is minimized to reject the heat dissipation of TECs from the hot side to the radiator efficiently. The size and surface coating of radiator are optimized to compromise heat reject ion requirements and system constraints. Based on above work, transient thermal analysis of FPA is performed. FPA prototype model has been developed and thermal vacuum/balance test has been accomplished. From the test, temperature of key parts and working parameters of TECs in extreme cases have been acquired. Test results show that CCD can be controlled below -65°C and all parts worked well during the test. All of these verified the thermal design of FPA and some lessons will be presented in this

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

    PubMed

    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.

  16. Improved performance of HgCdTe infrared detector focal plane arrays by modulating light field based on photonic crystal structure

    SciTech Connect

    Liang, Jian; Hu, Weida Ye, Zhenhua; Li, Zhifeng; Chen, Xiaoshuang Lu, Wei; Liao, Lei

    2014-05-14

    An HgCdTe long-wavelength infrared focal plane array photodetector is proposed by modulating light distributions based on the photonic crystal. It is shown that a promising prospect of improving performance is better light harvest and dark current limitation. To optimize the photon field distributions of the HgCdTe-based photonic crystal structure, a numerical method is built by combining the finite-element modeling and the finite-difference time-domain simulation. The optical and electrical characteristics of designed HgCdTe mid-wavelength and long-wavelength photon-trapping infrared detector focal plane arrays are obtained numerically. The results indicate that the photon crystal structure, which is entirely compatible with the large infrared focal plane arrays, can significantly reduce the dark current without degrading the quantum efficiency compared to the regular mesa or planar structure.

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

    SciTech Connect

    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.; 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.

  18. Toward 17µm pitch heterogeneously integrated Si/SiGe quantum well bolometer focal plane arrays

    NASA Astrophysics Data System (ADS)

    Ericsson, Per; Fischer, Andreas C.; Forsberg, Fredrik; Roxhed, Niclas; Samel, Björn; Savage, Susan; Stemme, Göran; Wissmar, Stanley; Öberg, Olof; Niklaus, Frank

    2011-06-01

    Most of today's commercial solutions for un-cooled IR imaging sensors are based on resistive bolometers using either Vanadium oxide (VOx) or amorphous Silicon (a-Si) as the thermistor material. Despite the long history for both concepts, market penetration outside high-end applications is still limited. By allowing actors in adjacent fields, such as those from the MEMS industry, to enter the market, this situation could change. This requires, however, that technologies fitting their tools and processes are developed. Heterogeneous integration of Si/SiGe quantum well bolometers on standard CMOS read out circuits is one approach that could easily be adopted by the MEMS industry. Due to its mono crystalline nature, the Si/SiGe thermistor material has excellent noise properties that result in a state-ofthe- art signal-to-noise ratio. The material is also stable at temperatures well above 450°C which offers great flexibility for both sensor integration and novel vacuum packaging concepts. We have previously reported on heterogeneous integration of Si/SiGe quantum well bolometers with pitches of 40μm x 40μm and 25μm x 25μm. The technology scales well to smaller pixel pitches and in this paper, we will report on our work on developing heterogeneous integration for Si/SiGe QW bolometers with a pixel pitch of 17μm x 17μm.

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

    NASA Astrophysics Data System (ADS)

    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

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

    USGS Publications Warehouse

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

    2016-01-01

    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

  1. Trade-offs and difficulties of the vertical photoconductor: a novel device structure suitable for HgCdTe two-dimensional infrared focal plane arrays

    NASA Astrophysics Data System (ADS)

    Bhan, R. K.; Dhar, V.; Mittal, Vandana

    1999-10-01

    Recently Siliquini and Faraone [J.F. Siliquini, L. Faraone, Infrared Phys. Technol. 38 (1997) 205] have proposed vertical photoconductive device (PC) based two-dimensional long wavelength infrared region focal plane arrays (LWIR FPAs). In this note, we examine some trade-offs and difficulties of this proposed structure.

  2. Focal plane arrays for submillimeter waves using two-dimensional electron gas elements: A grant under the Innovative Research Program

    NASA Technical Reports Server (NTRS)

    Yngvesson, K. Sigfrid; Lau, Kei-May

    1992-01-01

    This final report describes a three-year research effort, aimed at developing new types of THz low noise receivers, based on bulk effect ('hot electron') nonlinearities in the Two-Dimensional Electron Gas (2DEG) Medium, and the inclusion of such receivers in focal plane arrays. 2DEG hot electron mixers have been demonstrated at 35 and 94 GHz with three orders of magnitude wider bandwidth than previous hot electron mixers, which use bulk InSb. The 2DEG mixers employ a new mode of operation, which was invented during this program. Only moderate cooling is required for this mode, to temperatures in the range 20-77 K. Based on the results of this research, it is now possible to design a hot electron mixer focal plane array for the THz range, which is anticipated to have a DSB receiver noise temperature of 500-1000K. In our work on this grant, we have found similar results the the Cronin group (resident at the University of Bath, UK). Neither group has so far demonstrated heterodyne detection in this mode, however. We discovered and explored some new effects in the magnetic field mode, and these are described in the report. In particular, detection of 94 GHz and 238 GHz, respectively, by a new effect, 'Shubnikov de Haas detection', was found to be considerably stronger in our materials than the cyclotron resonance detection. All experiments utilized devices with an active 2DEG region of size of the order of 10-40 micrometers long, and 20-200 micrometers wide, formed at the heterojunction between AlGaAs and GaAs. All device fabrication was performed in-house. The materials for the devices were also grown in-house, utilizing OMCVD (Organo Metallic Chemical Vapor Deposition). In the course of this grant, we developed new techniques for growing AlGaAs/GaAs with mobilities equalling the highest values published by any laboratory. We believe that the field of hot electron mixers and detectors will grow substantially in importance in the next few years, partly as a result of

  3. Real-time 3D millimeter wave imaging based FMCW using GGD focal plane array as detectors

    NASA Astrophysics Data System (ADS)

    Levanon, Assaf; Rozban, Daniel; Kopeika, Natan S.; Yitzhaky, Yitzhak; Abramovich, Amir

    2014-03-01

    Millimeter wave (MMW) imaging systems are required for applications in medicine, communications, homeland security, and space technology. This is because there is no known ionization hazard for biological tissue, and atmospheric attenuation in this range of the spectrum is relatively low. The lack of inexpensive room temperature imaging systems makes it difficult to give a suitable MMW system for many of the above applications. 3D MMW imaging system based on chirp radar was studied previously using a scanning imaging system of a single detector. The system presented here proposes to employ a chirp radar method with a Glow Discharge Detector (GDD) Focal Plane Array (FPA) of plasma based detectors. Each point on the object corresponds to a point in the image and includes the distance information. This will enable 3D MMW imaging. The radar system requires that the millimeter wave detector (GDD) will be able to operate as a heterodyne detector. Since the source of radiation is a frequency modulated continuous wave (FMCW), the detected signal as a result of heterodyne detection gives the object's depth information according to value of difference frequency, in addition to the reflectance of the image. In this work we experimentally demonstrate the feasibility of implementing an imaging system based on radar principles and FPA of GDD devices. This imaging system is shown to be capable of imaging objects from distances of at least 10 meters.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Crack-free AlGaN for solar-blind focal plane arrays through reduced area epitaxy

    NASA Astrophysics Data System (ADS)

    Cicek, E.; McClintock, R.; Vashaei, Z.; Zhang, Y.; Gautier, S.; Cho, C. Y.; Razeghi, M.

    2013-02-01

    We report on crack reduction for solar-blind ultraviolet detectors via the use of a reduced area epitaxy (RAE) method to regrow on patterned AlN templates. With the RAE method, a pre-deposited AlN template is patterned into isolated mesas in order to reduce the formation of cracks in the subsequently grown high Al-content AlxGa1-xN structure. By restricting the lateral dimensions of the epitaxial growth area, the biaxial strain is relaxed by the edges of the patterned squares, which resulted in ˜97% of the pixels being crack-free. After successful implementation of RAE method, we studied the optical characteristics, the external quantum efficiency, and responsivity of average pixel-sized detectors of the patterned sample increased from 38% and 86.2 mA/W to 57% and 129.4 mA/W, respectively, as the reverse bias is increased from 0 V to 5 V. Finally, we discussed the possibility of extending this approach for focal plane array, where crack-free large area material is necessary for high quality imaging.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. MCT-Based LWIR and VLWIR 2D Focal Plane Detector Arrays for Low Dark Current Applications at AIM

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    We present our latest results on n-on- p as well as on p-on- n low dark current planar mercury cadmium telluride (MCT) photodiode technology long wavelength infrared (LWIR) and very long wavelength infrared (VLWIR) two-dimensional focal plane arrays (FPAs) with quantum efficiency (QE) cut-off wavelength >11 μm at 80 K and a 512 × 640 pixel format FPA at 20 μm pitch stitched from two 512 × 320 pixel photodiode arrays. Significantly reduced dark currents as compared with Tennant's "Rule 07" are demonstrated in both polarities while retaining good detection efficiency ≥60% for operating temperatures between 30 K and 100 K. This allows for the same dark current performance at 20 K higher operating temperature than with previous AIM INFRAROT-MODULE GmbH (AIM) technology. For p-on- n LWIR MCT FPAs, broadband photoresponse nonuniformity of only about 1.2% is achieved at 55 K with low defective pixel numbers. For an n-on- p VLWIR MCT FPA with 13.6 μm cut-off at 55 K, excellent photoresponse nonuniformity of about 3.1% is achieved at moderate defective pixel numbers. This advancement in detector technology paves the way for outstanding signal-to-noise ratio performance infrared detection, enabling cutting-edge next-generation LWIR/VLWIR detectors for space instruments and devices with higher operating temperature and low size, weight, and power for field applications.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Magnetization transfer and T2 quantitation in normal appearing cortical gray matter and white matter adjacent to focal abnormality in patients with traumatic brain injury.

    PubMed

    Kumar, Rajesh; Gupta, Rakesh K; Rao, Sajja B; Chawla, Sanjeev; Husain, Mazhar; Rathore, Ram K S

    2003-10-01

    Traumatic brain injury (TBI) is one of the commonest causes of morbidity and mortality in the developed countries with posttraumatic epilepsy and functional disability being its major sequelae. The purpose of this study was to test the hypothesis whether the normal appearing adjacent gray and white matter regions on T2 and T1 weighted magnetization transfer (MT) weighted images show any abnormality on quantitative imaging in patients with TBI. A total of 51 patients with TBI and 10 normal subjects were included in this study. There were significant differences in T2 and MT ratio values of T2 weighted and T1 weighted MT normal appearing gray matter regions adjacent to focal image abnormality compared to normal gray matter regions in the normal individuals as corresponding contralateral regions of the TBI patient's group (p < 0.05). However the adjoining normal appearing white matter quantitative values did not show any significant change compared to the corresponding contralateral normal white matter values. We conclude that quantitative T2 and MT ratio values provide additional abnormality in patients with TBI that is not discernable on conventional T2 weighted and T1 weighted MT imaging especially in gray matter. This additional information may be of value in overall management of these patients with TBI.

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

    NASA Astrophysics Data System (ADS)

    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

  13. Reliable Transport over SpaceWire for James Webb Space Telescope (JWST) Focal Plane Electronics (FPE) Network

    NASA Technical Reports Server (NTRS)

    Rakow, Glenn; Schnurr, Richard; Dailey, Christopher; Shakoorzadeh, Kamdin

    2003-01-01

    NASA's James Webb Space Telescope (JWST) faces difficult technical and budgetary challenges to overcome before it is scheduled launch in 2010. The Integrated Science Instrument Module (ISIM), shares these challenges. The major challenge addressed in this paper is the data network used to collect, process, compresses and store Infrared data. A total of 114 Mbps of raw information must be collected from 19 sources and delivered to the two redundant data processing units across a twenty meter deployed thermally restricted interface. Further data must be transferred to the solid-state recorder and the spacecraft. The JWST detectors are kept at cryogenic temperatures to obtain the sensitivity necessary to measure faint energy sources. The Focal Plane Electronics (FPE) that sample the detector, generate packets from the samples, and transmit these packets to the processing electronics must dissipate little power in order to help keep the detectors at these cold temperatures. Separating the low powered front-end electronics from the higher-powered processing electronics, and using a simple high-speed protocol to transmit the detector data minimize the power dissipation near the detectors. Low Voltage Differential Signaling (LVDS) drivers were considered an obvious choice for physical layer because of their high speed and low power. The mechanical restriction on the number cables across the thermal interface force the Image packets to be concentrated upon two high-speed links. These links connect the many image packet sources, Focal Plane Electronics (FPE), located near the cryogenic detectors to the processing electronics on the spacecraft structure. From 12 to 10,000 seconds of raw data are processed to make up an image, various algorithms integrate the pixel data Loss of commands to configure the detectors as well as the loss of science data itself may cause inefficiency in the use of the telescope that are unacceptable given the high cost of the observatory. This

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

    PubMed

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

    2015-06-16

    Microplastics (<5 mm) have been documented in environmental samples on a global scale. While these pollutants may enter aquatic environments via wastewater treatment facilities, the abundance of 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. Design, development, characterization and qualification of infrared focal plane area array detectors for space-borne imaging applications

    NASA Astrophysics Data System (ADS)

    Jain, Ankur; Banerjee, Arup

    2016-05-01

    This paper discusses the design, development, characterization and qualification aspects of large format Infrared Focal Plane Arrays (IRFPA) required for panchromatic, multi-, hyper- and ultra-spectral imaging applications from a space-borne imager. Detection of feeble radiant flux from the intended target in narrow spectral bands requires a highly sensitive low noise sensor array with high well capacity. For this the photodiode arrays responsive in desired spectral band are grown using different growth techniques and flip-chip bonded with a suitable Si Read-out ICs (ROICs) for signal conditioning. IR detectors require cryogenic cooling to achieve background limited performance. Although passive radiative cooling is always the preferred choice of cooling in space, it is not suitable for cooling IRFPAs due to high thermal loads. To facilitate characterization of IRFPAs and cool them to desired cryogenic temperature, an Integrated Detector Dewar Cooler Assembly (IDDCA) is essential where the detector array sits over the cold tip of an active cooler and the detector cooler assembly is vacuum sealed in a thermally isolated Dewar. A cold shield above the sensor array inside the Dewar restricts its field-of-view and a cold filter fine tunes its spectral response. In this paper, various constituents of an IRFPA like sensor array materials, growth techniques, ROICs, filters, cold shields, cooling techniques etc., their types and selection criteria for different applications are discussed in detail. Design aspects of IRFPA characterization test bench, challenges involved in radiometric and spectral characterization and space qualification of such IDDCA based IRFPAs are also discussed.

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

    NASA Astrophysics Data System (ADS)

    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).

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. A theoretical study of the local electronic structure of two adjacent CuOplanes in YBa 2Cu 3O 7

    NASA Astrophysics Data System (ADS)

    Suter, H. U.; Stoll, E. P.; Hüsser, P.; Schafroth, S.; Meier, P. F.

    1997-08-01

    To reveal the local electronic structure of the two adjacent CuOplanes in YBa 2Cu 3O 7, ab initio studies on a small cluster (Cu 2Y 4O 8) were performed. Electron correlation was investigated with both density functional theory and Møller-Plesset theory. The ionisation energies, electron affinities adn the singlet-triplet differences are discussed with respect to model Hamiltonians of high-T c compounds.

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

    PubMed

    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.

  1. Long-Wavelength 640 x 484 GaAs/Al(x)Ga(1-x)As Quantum Well Infrared Photodetector Focal Plane Array Camera

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Hong, W.; Sundaram, M.; Carralejo, R.; Shott, C. A.; Maker, P. D.; Miller, R. E.

    1997-01-01

    A 9 micrometers cutoff 640 x 484 hand-held quantum well infrared photodetector (QWIP) camera has been demonstrated. Excellent imagery, with a noise equivalent differential temperature (NE.deltaT) of 43 mK has been achieved. In this paper, we discuss the development of this very sensitive long wavelength infrared (LWIR) camera based on a GaAs/AlGaAs QWIP focal plane array (FPA) and its performance in quantum efficiency, NE.deltaT, uniformity, and operability.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    Wada, Asma

    advantages arise from the fact that (TPEF) imaging is done with 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.

  5. AlGaN-based focal plane arrays for selective UV imaging at 310nm and 280nm and route toward deep UV imaging

    NASA Astrophysics Data System (ADS)

    Reverchon, Jean-Luc; Robo, Jean-Alexandre; Truffer, Jean-Patrick; Caumes, Jean-Pascal; Mourad, Idir; Brault, Julien; Duboz, Jean-Yves

    2007-10-01

    The fast development of nitrides has given the opportunity to investigate AlGaN as a material for ultraviolet detection. Such camera present an intrinsic spectral selectivity and an extremely low dark current at room temperature. It can compete with technologies based on photocathodes, MCP intensifiers, back thinned CCD or hybrid CMOS focal plane arrays (FPA) for low flux measurements. AlGaN based cameras allow UV imaging without filters or with simplified ones in harsh solar blind conditions. Few results on camera have been shown in the last years, but the ultimate performances of AlGaN photodiodes couldn't be achieved due to parasitic illumination of multiplexers, responsivity of p layers in p-i-n structures, or use of cooled readout circuit. Such issues have prevented up to now a large development of this technology. We present results on focal plane array of 320x256 pixels with a pitch of 30μm for which Schottky photodiodes are multiplexed with a readout circuit protected by black matrix at room temperature. Theses focal plane present a peak reponsivity around 280nm and 310nm with a rejection of visible light of four decades only limited by internal photoemission in contact. Then we will show the capability to outdoor measurements. The noise figure is due to readout noise of the multiplexer and we will investigate the ultimate capabilities of Schottky diodes or Metal- Semiconductor-Metal (MSM) technologies to detect extremely low signal. Furthermore, we will consider deep UV measurements on single pixels MSM from 32nm to 61nm in a front side illumination configuration. Finally, we will define technology process allowing backside illumination and deep UV imaging.

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

    NASA Technical Reports Server (NTRS)

    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.

  7. 15-micro-m 128 x 128 GaAs/Al(x)Ga(1-x) As Quantum Well Infrared Photodetector Focal Plane Array Camera

    NASA Technical Reports Server (NTRS)

    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.

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

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    Wetzel, David L.; Nasse, Michael J.

    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 μm 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.

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

    PubMed Central

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

    2014-01-01

    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. PMID:25195849

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

    PubMed

    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.

  12. Comparison of designs of off-axis Gregorian telescopes for millimeter-wave large focal-plane arrays.

    PubMed

    Hanany, Shaul; Marrone, Daniel P

    2002-08-01

    We compare the diffraction-limited field of view (FOV) provided by four types of off-axis Gregorian telescopes: the classical Gregorian, the aplanatic Gregorian, and the designs that cancel astigmatism and both astigmatism and coma. The analysis is carried out with telescope parameters that are appropriate for satellite and balloonborne millimeter- and submillimeter-wave astrophysics. We find that the design that cancels both coma and astigmatism provides the largest flat FOV, approximately 21 square deg. We also find that the FOV can be increased by approximately 15% by means of optimizing the shape and location of the focal surface.

  13. 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.

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Analysis of the Maillard reaction in human hair using Fourier transform infrared spectroscopic imaging and a focal-plane array detector.

    PubMed

    Jung, In-Keun; Park, Sang-Chul; Bin, Sung-Ah; Roh, Young Sup; Lee, John Hwan; Kim, Boo-Min

    2016-03-01

    The Maillard reaction has been well researched and used in the food industry and the fields of environmental science and organic chemistry. Here, we induced the Maillard reaction inside human hair and analyzed its effects by using Fourier transform infrared spectroscopy with a focal-plane array (FTIR-FPA) detector. We used arginine (A), glycine (G), and D-xylose (X) to generate the Maillard reaction by dissolving them in purified water and heating it to 150 °C. This label-free process generated a complex compound (named AGX after its ingredients) with a monomer structure, which was determined by using nuclear magnetic resonance (NMR) and FTIR-FPA. This compound was stable in hair and substantially increased its tensile strength. To our knowledge, we are the first to report the formation of this monomer in human hair, and our study provides insights into a new method that could be used to improve the condition of damaged or aging hair.

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

    PubMed

    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.

  17. Quasi-optical verification of the focal plane optics of the heterodyne instrument for the far-infrared (HIFI)

    NASA Astrophysics Data System (ADS)

    Candotti, Massimo; Cahill, Gary A.; Finn, Timothy J.; Jellema, Willem; Lavelle, John; Murphy, J. Anthony; O'Sullivan, Creidhe; Trappe, Neil A.

    2004-09-01

    HIFI is one of the three instruments for the Herschel Space Observatory, an ESA cornerstone mission. HIFI is a high resolution spectrometer operating at wavelengths between 157 and 625 µm. The need for a compact layout reducing the volume and mass as much as possible has important consequences for the optical design. Many mirrors are located in the near-field of the propagating beam. Especially in the long wavelength limit diffraction effects might therefore introduce significant amplitude and phase distortions. A classical geometrical optical approach is consequently inadequate. In this paper we present a rigorous quasi-optical analysis of the entire optical system including the signal path, local oscillator path and onboard calibration source optical layout. In order to verify the results of the front-to-end coherent propagation of the detector beams, near-field measurement facilities capable of measuring both amplitude and phase have beam developed. A remarkable feature of these facilities is that the absolute coordinates of the measured field components are known to within fractions of a wavelength. Both measured and simulated fields can therefore compared directly since they are referenced to one single absolute position. We present a comparison of experimental data with software predictions obtained from the following packages: GRASP (Physical Optics Analysis) and GLAD (Plane Wave Decomposition). We also present preliminary results for a method to correct for phase aberrations and optimize the mirror surfaces without changing the predesigned mechanical layout of the optical system.

  18. 4K×4K format 10μm pixel pitch H4RG-10 hybrid CMOS silicon visible focal plane array for space astronomy

    NASA Astrophysics Data System (ADS)

    Bai, Yibin; Tennant, William; Anglin, Selmer; Wong, Andre; Farris, Mark; Xu, Min; Holland, Eric; Cooper, Donald; Hosack, Joseph; Ho, Kenneth; Sprafke, Thomas; Kopp, Robert; Starr, Brian; Blank, Richard; Beletic, James W.; Luppino, Gerard A.

    2012-07-01

    Teledyne’s silicon hybrid CMOS focal plane array technology has matured into a viable, high performance and high- TRL alternative to scientific CCD sensors for space-based applications in the UV-visible-NIR wavelengths. This paper presents the latest results from Teledyne’s low noise silicon hybrid CMOS visible focal place array produced in 4K×4K format with 10 μm pixel pitch. The H4RG-10 readout circuit retains all of the CMOS functionality (windowing, guide mode, reference pixels) and heritage of its highly successful predecessor (H2RG) developed for JWST, with additional features for improved performance. Combined with a silicon PIN detector layer, this technology is termed HyViSI™ (Hybrid Visible Silicon Imager). H4RG-10 HyViSI™ arrays achieve high pixel interconnectivity (<99.99%), low readout noise (<10 e- rms single CDS), low dark current (<0.5 e-/pixel/s at 193K), high quantum efficiency (<90% broadband), and large dynamic range (<13 bits). Pixel crosstalk and interpixel capacitance (IPC) have been predicted using detailed models of the hybrid structure and these predictions have been confirmed by measurements with Fe-55 Xray events and the single pixel reset technique. For a 100-micron thick detector, IPC of less than 3% and total pixel crosstalk of less than 7% have been achieved for the HyViSI™ H4RG-10. The H4RG-10 array is mounted on a lightweight silicon carbide (SiC) package and has been qualified to Technology Readiness Level 6 (TRL-6). As part of space qualification, the HyViSI™ H4RG-10 array passed radiation testing for low earth orbit (LEO) environment.

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

    SciTech Connect

    Vishnyakov, A. V.; Stuchinsky, V. A. Brunev, D. V.; Zverev, A. V.; Dvoretsky, S. A.

    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.

  20. Study of LWIR and VLWIR Focal Plane Array Developments: Comparison Between p-on- n and Different n-on- p Technologies on LPE HgCdTe

    NASA Astrophysics Data System (ADS)

    Gravrand, O.; Mollard, L.; Largeron, C.; Baier, N.; Deborniol, E.; Chorier, Ph.

    2009-08-01

    The very long infrared wavelength (>14 μm) is a very challenging range for the design of mercury cadmium telluride (HgCdTe) large focal plane arrays (FPAs). The need (mainly expressed by the space industry) for very long wave FPAs appears very difficult to fulfil. High homogeneity, low defect rate, high quantum efficiency, low dark current, and low excess noise are required. Indeed, for such wavelength, the corresponding HgCdTe gap becomes smaller than 100 meV and each step from the metallurgy to the technology becomes critical. This paper aims at presenting a status of long and very long wave FPAs developments at DEFIR (LETI-LIR/Sofradir joint venture). This study will focus on results obtained in our laboratory for three different ion implanted technologies: n-on- p mercury vacancies doped technology, n-on- p extrinsic doped technology, and p-on- n arsenic on indium technology. Special focus is given to 15 μm cutoff n/ p FPA fabricated in our laboratory demonstrating high uniformity, diffusion and shot noise limited photodiodes at 50 K.

  1. Diffractive microlens with a cascade focal plane fabricated by single mask UV-photolithography and common KOH:H2O etching

    NASA Astrophysics Data System (ADS)

    Zhang, Xinyu; Li, Hui; Liu, Kan; Luo, Jun; Xie, Changsheng; Ji, An; Zhang, Tianxu

    2010-10-01

    A diffractive microlens with a cascade focal plane along the main optical axis of the device is fabricated using a low-cost technique mainly including single mask ultraviolet (UV) photolithography and dual-step KOH:H2O etching. Based on the evolutionary behavior of converse pyramid-shaped microholes (CPSMs) preshaped over a {1 0 0}-oriented silicon wafer in KOH etchant, the first-step KOH etching is performed to transfer initial square micro-openings in a SiO2 film grown by plasma enhanced chemical vapor deposition (PECVD) and patterned by single mask UV-photolithography, into CPSMs with needed dimension. After completely removing a thinned SiO2 mask, basic annular phase steps with a relatively steep sidewall and scheduled height can be shaped in the overlapped etching region between the neighboring silicon concave-arc microstructures evolved from CPSMs through the second-step KOH etching. Morphological measurements demonstrate a desirable surface of the silicon microlens with a roughness in nanometer scale and the feature height of the phase steps formed in the submicrometer range. Conventional optics measurements of the plastic diffractive microlens obtained by further hot embossing the fine microrelief phase map over the nickel mask made through a common electrochemical method indicate a highly efficient cascaded focusing performance.

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

    NASA Astrophysics Data System (ADS)

    Vishnyakov, A. V.; Stuchinsky, V. A.; Brunev, D. V.; Zverev, A. V.; Dvoretsky, S. A.

    2014-03-01

    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 jph 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 jph ≠ 0) charge-carrier diffusion length ld eff as a function of jph for jph → 0 inferred from our experimental data proved to be consistent with the behavior of ld eff vs jph 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.

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

    NASA Technical Reports Server (NTRS)

    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.

  4. Design and tolerance of a free-form optical system for an optical see-through multi-focal-plane display.

    PubMed

    Hu, Xinda; Hua, Hong

    2015-11-20

    By elegantly combining recent advancements of free-form optical technology and multi-focal-plane (MFP) display technology, we developed a high-performance true 3D augmented reality (AR) display that is capable of rendering a large volume of 3D scenes with accurate focus cues; this display overcomes the accommodation-convergence discrepancy problem in conventional AR display. In this paper, we concentrate on various aspects of engineering challenges in the design and integration of a free-form optical see-through eyepiece with MFP technology for our AR display prototype. We present the design and optimization strategy in coupling free-form optics with a rotational-symmetric lens system to achieve high image quality. A comprehensive tolerance analysis of this complicated optical system is also presented, including an effective tolerance method for random surface figure errors on aspheric and free-form surfaces. Finally, the image quality of the virtual display is evaluated, which shows the as-built performance matches very well with the optical design results and tolerance analysis.

  5. Focal plane infrared readout circuit

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor)

    2002-01-01

    An infrared imager, such as a spectrometer, includes multiple infrared photodetectors and readout circuits for reading out signals from the photodetectors. Each readout circuit includes a buffered direct injection input circuit including a differential amplifier with active feedback provided through an injection transistor. The differential amplifier includes a pair of input transistors, a pair of cascode transistors and a current mirror load. Photocurrent from a photodetector can be injected onto an integration capacitor in the readout circuit with high injection efficiency at high speed. A high speed, low noise, wide dynamic range linear infrared multiplexer array for reading out infrared detectors with large capacitances can be achieved even when short exposure times are used. The effect of image lag can be reduced.

  6. Pixel isolation of low dark-current large-format InAs/GaSb superlattice complementary barrier infrared detector focal plane arrays with high fill factor

    NASA Astrophysics Data System (ADS)

    Nguyen, Jean; Hill, Cory J.; Rafol, Don; Keo, Sam; Soibel, Alexander; Ting, David Z.-Y.; Mumolo, Jason; Liu, John; Gunapala, Sarath D.

    2011-01-01

    Low dark current and high fill factor are two crucial characteristics for the realization of the InAs/GaSb superlattice (SL) technology as third generation focal plane arrays (FPAs). Recent development proved high performance results for the complementary barrier infrared detector (CBIRD) design, and a high-quality etch technique is required to minimize surface leakage currents. We report on a n-CBIRD with 10.3 μm cutoff, exhibiting a responsivity of 1.7 A/W and dark current density of 1×10-5 A/cm2 at 77K under 0.2 V bias, without AR coating and without passivation. Results from four different mesa isolation techniques are compared on single element diodes: chemical wet etch using C4H6O6:H3PO4:H2O2:H2O, BCl3/Ar inductively coupled plasma (ICP), CH4/H2/Ar ICP, and CH4/H2/BCl3/Cl2/Ar ICP. The CH4/H2/BCl3/Cl2/Ar etched structures yielded more than 2.5 times improvement in dark current density and nearvertical sidewalls. Using this etching technique, we then implement a 1k x 1k p-CBIRD array with 11.5 μm cutoff and peak responsivity of 3 A/W. Operating at T = 80K, the array yielded a 81% fill factor with 98% operability and performance results of 21% quantum efficiency, 53 mK NE▵T, and NEI of 6.9×1013 photons/sec-cm2.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Isolating stem cells in the inter-follicular epidermis employing synchrotron radiation-based Fourier-transform infrared microspectroscopy and focal plane array imaging.

    PubMed

    Patel, Imran I; Harrison, Wesley J; Kerns, Jemma G; Filik, Jacob; Wehbe, Katia; Carmichael, Paul L; Scott, Andrew D; Philpott, Mike P; Frogley, Mark D; Cinque, Gianfelice; Martin, Francis L

    2012-10-01

    Normal function and physiology of the epidermis is maintained by the regenerative capacity of this tissue via adult stem cells (SCs). However, definitive identifying markers for SCs remain elusive. Infrared (IR) spectroscopy exploits the ability of cellular biomolecules to absorb in the mid-IR region (λ = 2.5-25 μm), detecting vibrational transitions of chemical bonds. In this study, we exploited the cell's inherent biochemical composition to discriminate SCs of the inter-follicular skin epidermis based on IR-derived markers. Paraffin-embedded samples of human scalp skin (n = 4) were obtained, and 10-μm thick sections were mounted for IR spectroscopy. Samples were interrogated in transmission mode using synchrotron radiation-based Fourier-transform IR (FTIR) microspectroscopy (15 × 15 μm) and also imaged employing globar-source FTIR focal plane array (FPA) imaging (5.4 × 5.4 μm). Dependent on the location of derived spectra, wavenumber-absorbance/intensity relationships were examined using unsupervised principal component analysis. This approach showed clear separation and spectral differences dependent on cell type. Spectral biomarkers concurrently associated with segregation of SCs, transit-amplifying cells and terminally-differentiated cells of epidermis were primarily PO(2)(-) vibrational modes (1,225 and 1,080 cm(-1)), related to DNA conformational alterations. FPA imaging coupled with hierarchical cluster analysis also indicated the presence of specific basal layer cells potentially originating from the follicular bulge, suggested by co-clustering of spectra. This study highlights PO (2) (-) vibrational modes as potential putative SC markers.

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

    NASA Astrophysics Data System (ADS)

    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 < 300 K depends on the intrinsic carrier concentration of the In0.53Ga0.47As material, implying that the dominant dark currents are generation and recombination (G-R) currents originating in the depletion regions of the double layer planar heterostructure (DLPH) photodiode. In the analytical model differences from bulk G-R behavior are modeled with a G-R like perimeter-dependent shunt current conjectured to originate at the InP/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

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

    PubMed

    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.

  11. Mixed Linear/Square-Root Encoded Single-Slope Ramp Provides Low-Noise ADC with High Linearity for Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Wrigley, Chris J.; Hancock, Bruce R.; Newton, Kenneth W.; Cunningham, Thomas J.

    2013-01-01

    Single-slope analog-to-digital converters (ADCs) are particularly useful for onchip digitization in focal plane arrays (FPAs) because of their inherent monotonicity, relative simplicity, and efficiency for column-parallel applications, but they are comparatively slow. Squareroot encoding can allow the number of code values to be reduced without loss of signal-to-noise ratio (SNR) by keeping the quantization noise just below the signal shot noise. This encoding can be implemented directly by using a quadratic ramp. The reduction in the number of code values can substantially increase the quantization speed. However, in an FPA, the fixed pattern noise (FPN) limits the use of small quantization steps at low signal levels. If the zero-point is adjusted so that the lowest column is onscale, the other columns, including those at the center of the distribution, will be pushed up the ramp where the quantization noise is higher. Additionally, the finite frequency response of the ramp buffer amplifier and the comparator distort the shape of the ramp, so that the effective ramp value at the time the comparator trips differs from the intended value, resulting in errors. Allowing increased settling time decreases the quantization speed, while increasing the bandwidth increases the noise. The FPN problem is solved by breaking the ramp into two portions, with some fraction of the available code values allocated to a linear ramp and the remainder to a quadratic ramp. To avoid large transients, both the value and the slope of the linear and quadratic portions should be equal where they join. The span of the linear portion must cover the minimum offset, but not necessarily the maximum, since the fraction of the pixels above the upper limit will still be correctly quantized, albeit with increased quantization noise. The required linear span, maximum signal and ratio of quantization noise to shot noise at high signal, along with the continuity requirement, determines the number of

  12. Multi-spectral Infrared Photodetectors and Focal Plane Arrays based on Band-engineered Type-II Indium-Arsenic / Gallium-Antimony Superlattices and its Variants

    NASA Astrophysics Data System (ADS)

    Huang, Edward Kwei-wei

    designs used in LWIR detectors were more "resistant" to the surface traps generated from the optimized ICP etching developed, than higher bandgap superlattices from the SWIR to the MWIR. Empirical evidence suggests that such a phenomenon could be explained through relative surface trap positions to the Fermi level, as well as to the conduction and valence band-edges of the designed superlattice. From an optical standpoint, high quantum efficiencies demand thick active regions and therefore high aspect ratio trenches to be defined in the semiconductor in order to preserve the optical detector volume or fill factor. Etched trenches as deep as 12microm and roughly 3microm in width have been demonstrated. These achievements provide the foundation for focal plane array development, especially for multi-spectral detectors where multiple p-n junctions are stacked together. Understanding how to etch the superlattice pixel has enabled a wide variety of hybrid IR FPAs to be demonstrated. Prior to multi-color camera development, single color cameras were first evaluated in the MWIR and LWIR. Background limited performances were achieved in both wavelength regimes with temperature sensitivities as low as 9mK (MWIR F#2.3 lens) and 19mK (LWIR F#2.0 lens) where as high as 99% of the pixels were found operable. The milestones achieved and realized make T2SLs a prime candidate for multi-color sensing. As requirements for infrared sensing become more stringent, demanding identification of the object rather than mere detection, imagers sensitive to a single waveband are no longer adequate in some applications. In these scenarios, the ability to see in multiple infrared wavebands through a single aperture camera is indispensable. In this work, dual-band material structures that sense the active SWIR to the passive LWIR were designed in combinations of SWIR/MWIR, MWIR/MWIR, MWIRL/LWIR, and LWIR/LWIR to operate as back-to-back diodes where both bands could either be imaged sequentially or

  13. 8-9 and 14-15 Micron Two-Color 640x486 GaAs/AlGaAs Quantum Well Infrared Photodetector (QWIP) Focal Plane Array Camera

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Singh, A.; Liu, J. K.; Rafol, S. B.; Luong, E. M.; Mumolo, J. M.; Tran, N. Q.; Vincent, J. D.; Shott, C. A.

    2000-01-01

    An optimized long-wavelength two-color Quantum Well Infrared Photodetector (QWIP) device structure has been designed. This device structure was grown on a three inch semi-insulating GaAs substrate by molecular beam epitaxy (MBE). This wafer was processed into several 640x486 format monolithically integrated 8-9 and 14-15 micron two color (or dual wavelength) QWIP focal plane arrays (FPAs). These FPAs were then hybridized to 640x486 silicon CMOS readout multiplexers. A thinned (i.e., substrate removed) FPA hybrid was integrated into a liquid helium cooled dewar to perform electrical and optical characterization and to demonstrate simultaneous two-color imagery. The 8-9 micron detectors in the FPA have shown background limited performance (BLIP) at 70 K operating temperature, at 300 K background with f/2 cold stop. The 14-15 micron detectors of the FPA have reached BLIP at 40 K operating temperature at the same background conditions. In this presentation we discuss the performance of this long-wavelength dualband QWIP FPA in quantum efficiency, detectivity, noise equivalent temperature difference (NEAT), uniformity, and operability.

  14. Study of the polarization dependence of the photoelectric effect in the soft X-ray band - A focal plane photoelectric stellar X-ray polarimeter for the Spectrum-X-Gamma mission

    NASA Technical Reports Server (NTRS)

    Heckler, A.; Blaer, A.; Kaaret, P.; Novick, R.

    1989-01-01

    An experimental study of the polarization dependence of the photoelectric effect in cesium iodide in the soft X-ray band was started (Heckler et al., 1989). At a grazing angle of 10 degrees and a photon energy of 2.6 keV, it is found that the photoelectric yield from a thin layer of evaporated cesium iodide varies by 12.4 percent as the polarization vector of the incident X-ray beam is rotated about the line-of-sight. The rotation angle corresponding to the maximum photoyield is displaced by 16 degrees from the normal to the photocathode. This modulation and phase shift are in good agreement with the results recently reported by Fraser, et al. (1989) It is shown that a focal plane stellar X-ray polarimeter based on this photoelectric effect will be substantially more efficient than convential X-ray polarimeters such as those based on either Bragg reflection or scattering from low atomic number targets.

  15. Focal Plane Array Technology for IR Detectors

    DTIC Science & Technology

    1996-06-01

    Bulk Crystals CdTe, CdSe , CdS, CdO, ZnTe, Cd(SSe) Continue: (HgCd)Te, (CdZn)Te Crystal growth: Vertical Bridgman Method (VBM), Horizontal Bridgman ...Method (HBM), Vertical Zone Melting (VZM), Vapour Phase Transport Method (VPTM), Travelling Heater Method (THM) Continue: Bridgman Growth from Melt of...growth of (HgCd)Te, is shown in Figs.2.1-2.2. Our Bridgman growth from melt of constant composition (BGCC) is based on a demand to ensure melt of

  16. Focal Plane Alignment Utilizing Optical CMM

    NASA Technical Reports Server (NTRS)

    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 is sketched in Figure 2(b) (the figure also shows the tapping tool and where to tap). At this point the fasteners for the PCB are torqued slightly so the PCB can still move. The PCB location is adjusted again with the tapping tool. This process is repeated 3 to 4 times until the final torque is achieved. The oversized mounting holes are then filled with a liquid bonding agent to secure the board in position (not shown in the sketch). A 10- to 30-micron mounting accuracy has been achieved utilizing this method..

  17. Medical Applications of IR Focal Plane Arrays

    DTIC Science & Technology

    2007-11-02

    near infrared reflectometer was designed and fabricated using laser (814 nm and 751 nm ) diodes and separate photodiode detector circuits. Because the...States pioneered the clinical use of infrared imaging in the late 1960s in neurology, surgery, oncology, dentistry , and dermatology. It became very...medicine, dermatology, ophthalmology, and dentistry . The impact of the above findings and developments form the basis for the continued exploitation of

  18. Precision Laser Annealing of Focal Plane Arrays

    SciTech Connect

    Bender, Daniel A.; DeRose, Christopher; Starbuck, Andrew Lea; Verley, Jason C.; Jenkins, Mark W.

    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.

  19. Statistical Earthquake Focal Mechanism Forecasts

    NASA Astrophysics Data System (ADS)

    Kagan, Y. Y.; Jackson, D. D.

    2013-12-01

    The new whole Earth focal mechanism forecast, based on the GCMT catalog, has been created. In the present forecast, the sum of normalized seismic moment tensors within 1000 km radius is calculated and the P- and T-axes for the focal mechanism are evaluated on the basis of the sum. Simultaneously we calculate an average rotation angle between the forecasted mechanism and all the surrounding mechanisms. This average angle shows tectonic complexity of a region and indicates the accuracy of the prediction. The method was originally proposed by Kagan and Jackson (1994, JGR). Recent interest by CSEP and GEM has motivated some improvements, particularly to extend the previous forecast to polar and near-polar regions. The major problem in extending the forecast is the focal mechanism calculation on a spherical surface. In the previous forecast as our average focal mechanism was computed, it was assumed that longitude lines are approximately parallel within 1000 km radius. This is largely accurate in the equatorial and near-equatorial areas. However, when one approaches the 75 degree latitude, the longitude lines are no longer parallel: the bearing (azimuthal) difference at points separated by 1000 km reach about 35 degrees. In most situations a forecast point where we calculate an average focal mechanism is surrounded by earthquakes, so a bias should not be strong due to the difference effect cancellation. But if we move into polar regions, the bearing difference could approach 180 degrees. In a modified program focal mechanisms have been projected on a plane tangent to a sphere at a forecast point. New longitude axes which are parallel in the tangent plane are corrected for the bearing difference. A comparison with the old 75S-75N forecast shows that in equatorial regions the forecasted focal mechanisms are almost the same, and the difference in the forecasted focal mechanisms rotation angle is close to zero. However, though the forecasted focal mechanisms are similar

  20. An uncommon focal epithelial hyperplasia manifestation.

    PubMed

    dos Santos-Pinto, Lourdes; Giro, Elisa Maria Aparecida; Pansani, Cyneu Aguiar; Ferrari, Junia; Massucato, Elaine Maria Sgavioli; Spolidório, Luis Carlos

    2009-01-01

    Focal epithelial hyperplasia is a rare, contagious disease associated with infection of the oral mucosa by human papillomavirus types 13 or 32, characterized by multiple soft papules of the same color as the adjacent normal mucosa. It mainly affects the lower lip, buccal mucosa, and tongue. The purpose of this case report was to describe a rare verrucal lesion located in the upper gingiva that was clinically and histologically consistent with focal epithelial hyperplasia.

  1. A Review of Focal Reducer Interferometer Systems

    DTIC Science & Technology

    1986-06-01

    searches. G.Courtes has also proposed a design for a focal reducer for the E.S.O. 3.6m. Ritchey -Chretien telescope (Fig. 4b). He uses a Schmidt camera...spaced components, with a modified Wynne camera design (Fig. 7). The instrument proposed used folded optics and would operate at the F/8 Ritchey Cretien ...G.Courtes for the 3.6m Ritchey Chretien telescope . a, telescope focal plane and field lens; b, collimator; c, camera. Figure 5 The focal reducer of A.B

  2. Analysis and Evaluation of Technical Data on the Photochromic and Non-Linear Optical Properties of Materials. Appendix. Eye/Sensor Protection by an Optical Fuse Mirror at a Focal Plane: Feasibility Assessment

    DTIC Science & Technology

    1989-08-07

    Outside the focal point the film need not be free standing but may be supported on a suitale sustance . One could envision a mirror/fuse system, located...8217 5U7SRAII to* - free filf% nsSJ P I0H o n the-wl wctijtvity. radially or in de9 mq ri of ia. less thar, focused spot size for artica! gains 10 to S or i Wst0...1. 15 P ! 08 0, ~l 1. O7i t.343 V . 98 OS OMBE 11 1. 19 -k i.1901 0.1391 B. Om 0. b376 0.52 CB CAS63 loc 1.656-06 1.6573? 0.154S 0.010C 0.B6, C.263S

  3. Focal Choroidal Excavation

    PubMed Central

    Cebeci, Zafer; Bayraktar, Şerife; Oray, Merih; Kır, Nur

    2016-01-01

    Focal choroidal excavation is a choroidal pit that can be detected by optical coherence tomography. Central serous chorioretinopathy, choroidal neovascularization and polypoidal choroidal vasculopathy are pathologies associated with focal choroidal excavation. In this article, we present the follow-up and treatment outcomes of three eyes of two patients with focal choroidal excavation. PMID:28050329

  4. Focal Choroidal Excavation.

    PubMed

    Cebeci, Zafer; Bayraktar, Şerife; Oray, Merih; Kır, Nur

    2016-12-01

    Focal choroidal excavation is a choroidal pit that can be detected by optical coherence tomography. Central serous chorioretinopathy, choroidal neovascularization and polypoidal choroidal vasculopathy are pathologies associated with focal choroidal excavation. In this article, we present the follow-up and treatment outcomes of three eyes of two patients with focal choroidal excavation.

  5. Statistical earthquake focal mechanism forecasts

    NASA Astrophysics Data System (ADS)

    Kagan, Yan Y.; Jackson, David D.

    2014-04-01

    Forecasts of the focal mechanisms of future shallow (depth 0-70 km) 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° spatial resolution, covering the latitude range from -75° to +75°, based on the Global Central Moment Tensor earthquake catalogue. In the new forecasts we have improved the spatial resolution to 0.1° 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 gridpoint. Simultaneously, we calculate an average rotation angle between the forecasted mechanism and all the surrounding mechanisms, using the method of Kagan & Jackson proposed in 1994. This average angle reveals the level of tectonic complexity of a region and indicates the accuracy of the prediction. The procedure becomes problematical where longitude lines are not approximately parallel, and where shallow earthquakes are so sparse that an adequate sample spans very large distances. North or south of 75°, the azimuths of points 1000 km away may vary by about 35°. We solved this problem by calculating focal mechanisms on a plane tangent to the Earth's surface at each forecast point, correcting for the rotation of the longitude lines at the locations of earthquakes included in the averaging. The corrections are negligible between -30° and +30° latitude, but outside that band uncorrected rotations can be significantly off. Improved forecasts at 0.5° and 0.1° resolution are posted at http://eq.ess.ucla.edu/kagan/glob_gcmt_index.html.

  6. Seismotectonics of Northeastern United States and adjacent Canada

    SciTech Connect

    Yang, J.; Aggarwal, Y.P.

    1981-06-10

    Data for local earthquakes recorded by a network of stations in northeastern United States and adjacent Canada were analyzed to study the seismicity, the relationship between earthquakes and known faults, the state of stress, and crustal and upper mantle velocity structure. In addition, portable seismographs were deployed in the field to study aftershocks. As a result, accurate locations for about 364 local earthquakes (2< or =m/sub b/< or =5) and 22 focal mechanism solutions were determined. A comparison of the spatial distribution of these events (1970--1979) with historical earthquakes (1534--1959) reveals that seismic activity in the northeast is relatively stationary in space: those areas that have had little or no seismicity historically are relatively aseismic today, whereas the historically active areas are also active today. The instrumental locations, historical seismicity, and focal mechanism solutions show an internal consistency that help us distinguish two distinct seismogenic provinces. (1) The Adirondack-western Quebec province is a northwesterly trending zone of seismic activity, about 200 km wide and at least 500 km long, extending from the SE Adirondacks into western Quebec, Canada. Thrust faulting on planes striking NNW to NW appears to predominate, and the inferred axis of maximum horizontal compression is largely uniform and trends WSW, nearly parallel to the calculated absolute plate motion of North America. Little or no seismicity is found where anorthosite outcrops at the surface. Correlations between gravity anomalies and earthquake locations suggest that seismic activity in this zone is localized to regions of steep NE or SW gradient in Bouguer anomalies. This zone does not appear to extend southeastward to Boston, as proposed by some workers. (2) The Appalachian province is a northeasterly trending zone of seismic activity extending from northern Virginia to New Brunswick, Canada.

  7. Research of aerial camera focal pane micro-displacement measurement system based on Michelson interferometer

    NASA Astrophysics Data System (ADS)

    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.

  8. Seismotectonics of northeastern United States and adjacent Canada

    NASA Astrophysics Data System (ADS)

    Yang, Jih-Ping; Aggarwal, Yash Pal

    1981-06-01

    Data for local earthquakes recorded by a network of stations in northeastern United States and adjacent Canada were analyzed to study the seismicity, the relationship between earthquakes and known faults, the state of stress, and crustal and upper mantle velocity structure. In addition, portable seismographs were deployed in the field to study aftershocks. As a result, accurate locations for about 364 local earthquakes (2 ≤ mb ≤ 5) and 22 focal mechanism solutions were determined. A comparison of the spatial distribution of these events (1970-1979) with historical earthquakes (1534-1959) reveals that seismic activity in the northeast is relatively stationary in space: those areas that have had little or no seismicity historically are relatively aseismic today, whereas the historically active areas are also active today. The instrumental locations, historical seismicity, and focal mechanism solutions show an internal consistency that help us distinguish two distinct seismogenic provinces. (1) The Adirondack-western Quebec province is a northwesterly trending zone of seismic activity, about 200 km wide and at least 500 km long, extending from the SE Adirondacks into western Quebec, Canada. Thrust faulting on planes striking NNW to NW appears to predominate, and the inferred axis of maximum horizontal compression is largely uniform and trends WSW, nearly parallel to the calculated absolute plate motion of North America. Little or no seismicity is found where anorthosite outcrops at the surface. Correlations between gravity anomalies and earthquake locations suggest that seismic activity in this zone is localized to regions of steep NE or SW gradient in Bouguer anomalies. This zone does not appear to extend southeastward to Boston, as proposed by some workers. (2) The Appalachian province is a northeasterly trending zone of seismic activity extending from northern Virginia to New Brunswick, Canada. Highangle reverse or thrust faulting on N to NE trending planes

  9. Partial (focal) seizure

    MedlinePlus

    ... Jacksonian seizure; Seizure - partial (focal); Temporal lobe seizure; Epilepsy - partial seizures ... Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff ... Practice . 7th ed. Philadelphia, PA: Elsevier; 2016:chap 101. ...

  10. Focal Mechanism determination of local M

    NASA Astrophysics Data System (ADS)

    Vales, Dina; Custório, Susana; Carrilho, Fernando

    2015-04-01

    We determine the focal mechanisms of local small (ML<3.9) earthquakes that occurred between 2013 and 2014 in mainland Portugal. These low magnitude events were recorded by several stations that provide first-motion polarity solutions. However, only few stations are located near the epicenter and record a waveform with a signal-to-noise ratio (SNR) high enough to allow full waveform modelling. To overcome this limitation, we used a new approach called cyclic scanning of the polarity solutions (CSPS) (Fojtíková and Zahradnik, 2014), which performs a joint inversion of full waveform and first motion polarities to retrieve the focal mechanism. This methodology has the advantage of yielding reliable focal mechanism solutions, even when high SNR waveforms are available from only a few near field stations (or in the limiting case, only with one single station). To apply the CSPS method one needs to: i) run the the FOCal MEChanism (FOCMEC) code (Snoke, 2003) to obtain a suite of the DC solutions corresponding to the first motion polarities, and then ii) perform the waveform modelling in order to decrease the uncertainty. The ISOLated Asperities (ISOLA) software (Sokos and Zahradník, 2008, 2013) is used in this second step. We applied this method to weak events recorded by a network of 30 broadband seismic stations that transmit data in real-time to Instituto Português do Mar e da Atmosfera (IPMA), the institution responsible for seismic monitoring in Portugal. We interpret the obtained fault plane solutions in light of active faults and regional tectonics, and in comparison with focal mechanisms previously inferred for events in the region. The focal mechanisms obtained for small earthquakes allow us to significantly expand the database of available focal mechanisms in mainland Portugal, contributing to the understanding of active deformation in the region.

  11. Testing wetland axioms at a watershed scale: Case studies of the aggregate hydrologic effects of non-adjacent wetlands

    EPA Science Inventory

    Wetlands not adjacent to streams (i.e. “non-adjacent wetlands”) are hypothesized to affect downgradient hydrology in a number of ways. Non-adjacent wetlands may, for example, attenuate peak flows, serve as focal points for groundwater recharge, and decrease streamflow...

  12. Enabling Large Focal Plane Arrays Through Mosaic Hybridization

    NASA Technical Reports Server (NTRS)

    Miller, Timothy M.; Jhabvala, Christine A.; Leong, Edward; Costen, Nicholas P.; Sharp, Elmer; Adachi, Tomoko; Benford, Dominic J.

    2012-01-01

    We have demonstrated advances in mosaic hybridization that will enable very large format far-infrared detectors. Specifically we have produced electrical detector models via mosaic hybridization yielding superconducting circuit paths by hybridizing separately fabricated sub-units onto a single detector unit. The detector model was made on a 100mm diameter wafer while four model readout quadrant chips were made from a separate 100mm wafer. The individually fabricated parts were hybridized using a flip-chip bonder to assemble the detector-readout stack. Once all of the hybridized readouts were in place, a single, large and thick silicon substrate was placed on the stack and attached with permanent epoxy to provide strength and a Coefficient of Thermal Expansion match to the silicon components underneath. Wirebond pads on the readout chips connect circuits to warm readout electronics; and were used to validate the successful superconducting electrical interconnection of the model mosaic-hybrid detector. This demonstration is directly scalable to 150 mm diameter wafers, enabling pixel areas over ten times the area currently available.

  13. NIRCA ASIC for the readout of focal plane arrays

    NASA Astrophysics Data System (ADS)

    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.

  14. Latest Generation CMOS Hybrid Focal Planes: First Astrometric Results

    DTIC Science & Technology

    2010-01-01

    ABSTRACT
 
 We
 present
 the
 first
 ground‐based
 astrometric
 testing
 results
conducted
using
the
second‐generation
 H4RG ‐10
A2
 CMOS
hybrid...format,
Teledyne
Imaging
Sensors
(TIS)
 H4RG 
Hybrid
 Visible
 Silicon
 Imager
 (HyViSI)
 Sensor
 Chip
 Assemblies
 (SCAs)
 since
 the
 development
 of...the
 first
 generation‐A1
 detector
 in
 2006
 (Dorland
 et
 al.
 2007).

 Indeed,
 USNO
 has
 continued
 to
 support
 a
 myriad
 of
 H4RG

  15. MEMS Terahertz Focal Plane Array With Optical Readout

    DTIC Science & Technology

    2016-06-01

    THz sensing can be achieved by integrating a metamaterial absorber with bi-material legs to form a sensor . Moveable mirror- like surfaces on the...optical readout system. In this thesis, the construction of the optical readout system for characterization of sensor pixels as well as THz imaging is...THz sensing can be achieved by integrating a metamaterial absorber with bi-material legs to form a sensor . Moveable mirror-like surfaces on the

  16. Focal plane optics in far-infrared and submillimeter astronomy

    NASA Technical Reports Server (NTRS)

    Hildebrand, R. H.

    1985-01-01

    The construction of airborne observatories, high mountain-top observatories, and space observatories designed especially for infrared and submillimeter astronomy has opened fields of research requiring new optical techniques. A typical far-IR photometric study involves measurement of a continuum spectrum in several passbands between approx 30 microns and 1000 microns and diffraction-limited mapping of the source. At these wavelengths, diffraction effects strongly influence the design of the field optics systems which couple the incoming flux to the radiation sensors (cold bolometers). The Airy diffraction disk for a typical telescope at submillimeter wavelengths approx 100 microns-1000 microns is many millimeters in diameter; the size of the field stop must be comparable. The dilute radiation at the stop is fed through a Winston nonimaging concentrator to a small cavity containing the bolometer. The purpose of this paper is to review the principles and techniques of infrared field optics systems, including spectral filters, concentrators, cavities, and bolometers (as optical elements), with emphasis on photometric systems for wavelengths longer than 60 microns.

  17. Focal plane optics in far-infrared and submillimeter astronomy

    NASA Technical Reports Server (NTRS)

    Hildebrand, R. H.

    1986-01-01

    The construction of airborne observatories, high mountain-top observatories, and space observatories designed especially for infrared and submillimeter astronomy has opened fields of research requiring new optical techniques. A typical far-IR photometric study involves measurement of a continuum spectrum in several passbands between approx 30 microns and 1000 microns and diffraction-limited mapping of the source. At these wavelengths, diffraction effects strongly influence the design of the field optics systems which couple the incoming flux to the radiation sensors (cold bolometers). The Airy diffraction disk for a typical telescope at submillimeter wavelengths approx 100 microns-1000 microns is many millimeters in diameter; the size of the field stop must be comparable. The dilute radiation at the stop is fed through a Winston nonimaging concentrator to a small cavity containing the bolometer. The purpose of this paper is to review the principles and techniques of infrared field optics systems, including spectral filters, concentrators, cavities, and bolometers (as optical elements), with emphasis on photometric systems for wavelengths longer than 60 microns.

  18. Monolithic Micromachined Quartz Resonator based Infrared Focal Plane Arrays

    DTIC Science & Technology

    2012-05-05

    Ping Kao, David L. Allara, Srinivas Tadigadapa. Study of Adsorption of Globular Proteins on Hydrophobic Surfaces, IEEE Sensors Journal, (11 2011): 0...David Allara, Srinivas Tadigadapa. Investigation of spontaneously adsorbed globular protein films using high-frequency bulk acoustic wave resonators...Conference. 2010/09/05 00:00:00, . : , 2012/05/08 20:19:32 9 Ping Kao, Matthew P. Chang, David Allara, Srinivas Tadigadapa. Systematic studies on globular

  19. Planck focal plane instruments: advanced modelization and combined analysis

    NASA Astrophysics Data System (ADS)

    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.

  20. Focal plane infrared readout circuit with automatic background suppression

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor); Yang, Guang (Inventor); Sun, Chao (Inventor); Shaw, Timothy J. (Inventor); Wrigley, Chris J. (Inventor)

    2002-01-01

    A circuit for reading out a signal from an infrared detector includes a current-mode background-signal subtracting circuit having a current memory which can be enabled to sample and store a dark level signal from the infrared detector during a calibration phase. The signal stored by the current memory is subtracted from a signal received from the infrared detector during an imaging phase. The circuit also includes a buffered direct injection input circuit and a differential voltage readout section. By performing most of the background signal estimation and subtraction in a current mode, a low gain can be provided by the buffered direct injection input circuit to keep the gain of the background signal relatively small, while a higher gain is provided by the differential voltage readout circuit. An array of such readout circuits can be used in an imager having an array of infrared detectors. The readout circuits can provide a high effective handling capacity.

  1. Analysis and Modeling for Thermal Focal Plane Arrays.

    DTIC Science & Technology

    1984-07-10

    or de- cision, unless so designated by other documentation., Tia docuirent a bci aj-2t1 vd kmr pWlj-? rohlus. -rd WJ0: its a esearch 2002 HOGBACK ...SCIENTIFIC & TECHNICAL REPORT paration FINAL TECHNICAL REPORT 2002 HOGBACK ROAD. SUITE 19 ANN ARBOR. MICHIGAN 48104 10 JULY 1984 CDRL A004 Accession For NTIS...PROGRAM ELEMENT. PROJECT. TASK AREA & WORK UNIT NUMBERS Nichols Research Corporation 2002 Hogback Road, Suite 19 Ann Arbor, MI 48104 .. 11

  2. New developments on InGaAs focal plane array

    NASA Astrophysics Data System (ADS)

    Coussement, J.; Rouvié, A.; Oubensaid, E. H.; Huet, O.; Hamard, S.; Truffer, J.-P.; Pozzi, M.; Maillart, P.; Reibel, Y.; Costard, E.; Billon-Lanfrey, D.

    2014-06-01

    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 recent transfer of imagery activities from III-VLab to Sofradir provides a framework for the production activity with the manufacturing of high performances products: CACTUS320 SW and CACTUS640 SW. The developments, begun at III-Vlab towards VGA format with 15μm pixel pitch, lead today to the industrialization of a new product: SNAKE SW. 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 640×512 @ 15μm module appears as well suited to answer the needs of a wide range of applications. In this paper, we will present the Sofradir InGaAs technology, some performances optimization and the last developments leading to SNAKE SW.

  3. Thermal Microphotonic Focal Plane Array (TM-FPA).

    SciTech Connect

    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.

  4. Enabling Large Focal Plane Arrays Through Mosaic Hybridization

    NASA Technical Reports Server (NTRS)

    Miller, Timothy M.; Jhabvala, Christine A.; Leong, Edward; Costen, Nick P.; Sharp, Elmer; Adachi, Tomoko; Benford, Dominic J.

    2012-01-01

    We have demonstrated advances in mosaic hybridization that will enable very large format far-infrared detectors. Specifically we have produced electrical detector models via mosaic hybridization yielding superconducting circuit patbs by hybridizing separately fabricated sub-units onto a single detector unit. The detector model was made on a 100mm diameter wafer while four model readout quadrant chips were made from a separate 100mm wafer. The individually fabric.ted parts were hybridized using a Suss FCI50 flip chip bonder to assemble the detector-readout stack. Once all of the hybridized readouts were in place, a single, large and thick silicon substrate was placed on the stack and attached with permanent epoxy to provide strength and a Coefficient of Thermal Expansion match to the silicon components underneath. Wirebond pads on the readout chips connect circuits to warm readout electronics; and were used to validate the successful superconducting electrical interconnection of the model mosaic-hybrid detector. This demonstration is directly scalable to 150 mm diameter wafers, enabling pixel areas over ten times the area currently available.

  5. Analysis of the thermal modes of Focal Plane Arrays

    NASA Astrophysics Data System (ADS)

    Pevtsov, E. Ph; Demenkova, T. A.; Luchnikov, P. A.; Vetrova, V. V.

    2017-01-01

    Techniques and programs for calculation and modeling of thermal characteristics of MEMS-designs of radiation thermal receivers are offered. Comparative estimates of characteristics of radiation receivers with heatsensitive thin films are executed. Results of researches can be used for development of original programs for modeling of thermal receivers of radiation.

  6. Focal plane arrays from UV up to VLWIR

    NASA Astrophysics Data System (ADS)

    Costard, E.; Nedelcu, A.; Achouche, M.; Reverchon, J. L.; Truffer, J. P.; Huet, O.; Dua, L.; Robo, J. A.; Marcadet, X.; Brière de l'Isle, N.; Facoetti, H.; Bois, P.

    2007-10-01

    Since 2002, the THALES Group has been manufacturing sensitive arrays using QWIP technology based on GaAs and related III-V compounds, at the Alcatel-Thales-III-V Lab (formerly part of THALES Research and Technology Laboratory). In the past researchers claimed many advantages of QWIPs. Uniformity was one of these and has been the key parameter for the production to start. Another widely claimed advantage for QWIPs was the so-called band-gap engineering and versatility of the III-V processing allowing the custom design of quantum structures to fulfil the requirements of specific applications such as very long wavelength (VLWIR) or multispectral detection. In this presentation, we give the status of our LWIR QWIP production line, and also the current status of QWIPs for MWIR (<5μm) and VLWIR (>15μm) arrays. As the QWIP technology cannot cover the full electromagnetic spectrum, we develop other semiconductor compounds for SWIR and UV applications. We present here the status of our first FPA realization in UV with GaN alloy, and at 1.5μm with InGaAs photodiodes.

  7. SWIR InGaAs focal plane arrays in France

    NASA Astrophysics Data System (ADS)

    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. Focal Plane Arrays of Voltage-Biased Superconducting Bolometers

    NASA Technical Reports Server (NTRS)

    Myers, Michael J.; Clarke, John; Gildemeister, J. M.; Lee, Adrian T.; Richards, P. L.; Schwan, Dan; Skidmore, J. T.; Spieler, Helmuth; Yoon, Jongsoo

    2001-01-01

    The 200-micrometer to 3-mm wavelength range has great astronomical and cosmological significance. Science goals include characterization of the cosmic microwave background, measurement of the Sunyaev-Zel'dovich effect in galaxy clusters, and observations of forming galaxies. Cryogenic bolometers are the most sensitive broadband detectors in this frequency range. Because single bolometer pixels are reaching the photon noise limit for many observations, the development of large arrays will be critical for future science progress. Voltage-biased superconducting bolometers (VSBs) have several advantages compared to other cryogenic bolometers. Their strong negative electrothermal feedback enhances their linearity, speed, and stability. The large noise margin of the SQUID readout enables multiplexed readout schemes, which are necessary for developing large arrays. In this paper, we discuss the development of a large absorber-coupled array, a frequency-domain SQUID readout multiplexer, and an antenna-coupled VSB design.

  9. Optically coupled focal plane arrays using lenslets and multiplexers

    DOEpatents

    Veldkamp, Wilfrid B.

    1991-01-01

    A detector array including a substrate having an array of diffractive lenses formed on the top side of the substrate and an array of sensor elements formed on the backside of the substrate. The sensor elements within the sensor array are oriented on the backside so that each sensor is aligned to receive light from a corresponding diffractive lens of the lens array. The detector array may also include a second substrate having an array of diffractive elements formed on one of its surfaces, the second substrate being disposed above and in proximity to the top side of the other substrate so that the elements on the second substrate are substantially aligned with corresponding sensor elements and diffractive lenses on the other substrate.

  10. [Focal epithelial hyperplasia].

    PubMed

    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.

  11. Vitelliform focal choroidal excavation.

    PubMed

    Or, Chris; Forooghian, Farzin

    2014-05-30

    Focal choroidal excavations (FCE) are characterized by foveal or perifoveal choroid excavations seen on optical coherence tomography (OCT). The authors report a case of FCE associated with a vitelliform lesion within the excavation. A case of FCE associated with a small vitelliform lesion has been described previously, but the larger extent of the vitelliform lesion observed in the current case has not been previously reported. This may represent a novel category of FCE, vitelliform focal choroidal excavation, in which deposition of vitelliform material is associated with its development.

  12. X-ray sources of medical linear accelerators: focal and extra-focal radiation.

    PubMed

    Jaffray, D A; Battista, J J; Fenster, A; Munro, P

    1993-01-01

    A computerized tomography (CT) reconstruction technique has been used to make quantitative measurements of the size and shape of the focal spot in medical linear accelerators. Using this technique, we have measured the focal spots in a total of nine accelerators, including (i) two Varian Clinac 2100c's, (ii) two Atomic Energy of Canada Ltd. (AECL) Therac-25's, (iii) two AECL Therac 6's, (iv) a Siemens KD-2, (v) a Varian Clinac 600c (4 MV), and (vi) an AECL Therac-20. Some of these focal spots were monitored for changes over a 2-yr period. It has been found that (i) the size and shape of the source spot varies greatly between accelerators of different design ranging from 0.5 to 3.4 mm in full width at half maximum (FWHM); and (ii) for accelerators of the same design, the focal spots are very similar. In addition to the measurements of the focal spot, a new technique for measuring the magnitude and distribution of extra-focal radiation originating from the linear accelerator head (flattening filter, primary collimator) has also been developed. The extra-focal radiation produced by a Varian Clinac 2100c accelerator was measured using this technique and it was found that the extra-focal radiation accounts for as much as 8% of the total photon fluence reaching the isocenter. The majority (75%) of this extra-focal radiation originates from within a circle 6 cm in diameter at the target plane. The source MTFs for each of the measured focal spots have been calculated in order to assess their influence on the spatial resolution of verification images. The limiting spatial resolution (i.e., 10% modulation) for all the source MTFs is 1.8 mm-1 or greater when used for transmission radiography at a magnification of 1.2. The extra-focal radiation, which produces a low-frequency drop in the source MTFs of up to 8%, changes with field size. As a result, the source MTFs of linear accelerators depend not only on the design of individual accelerators and image magnification, but also

  13. Oral focal epithelial hyperplasia.

    PubMed

    Bassioukas, K; Danielides, V; Georgiou, I; Photos, E; Zagorianakou, P; Skevas, A

    2000-01-01

    Focal epithelial hyperplasia (FEH) or Heck disease, is a rare viral infection of the oral mucosa caused by HPV 13 or HPV 32. In Caucasians there have been only a few cases reported. We present the first case in Greece in a young Caucasian girl in which HPV 13 was detected with PCR analysis. The patient was successfully treated with CO2 laser.

  14. Focal region fields of distorted reflectors

    NASA Technical Reports Server (NTRS)

    Buris, N. E.; Kauffman, J. F.

    1988-01-01

    The problem of the focal region fields scattered by an arbitrary surface reflector under uniform plane wave illumination is solved. The physical optics (PO) approximation is used to calculate the current induced on the reflector. The surface of the reflector is described by a number of triangular domain-wise 5th degree bivariate polynomials. A 2-dimensional Gaussian quadrature is employed to numerically evaluate the integral expressions of the scattered fields. No Freshnel or Fraunhofer zone approximations are made. The relation of the focal fields problem to surface compensation techniques and other applications are mentioned. Several examples of distorted parabolic reflectors are presented. The computer code developed is included, together with instructions on its usage.

  15. Oral focal epithelial hyperplasia.

    PubMed

    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.

  16. Creation of identical multiple focal spots with prescribed axial distribution.

    PubMed

    Yu, Yanzhong; Zhan, Qiwen

    2015-10-01

    We present a scheme for the construction of coaxially equidistant multiple focal spots with identical intensity profiles for each individual focus and a predetermined number and spacing. To achieve this, the radiation field from an antenna is reversed and then gathered by high numerical aperture objective lenses. Radiation patterns from three types of line sources, i.e., the electric current, magnetic current and electromagnetic current distributions, with cosine-squared taper are respectively employed to generate predominately longitudinally polarized bright spots, azimuthally polarized doughnuts, and focal spots with a perfect spherically symmetric intensity distribution. The required illuminations at the pupil plane of a 4Pi focusing configuration for the creation of these identical multiple focal spots can be easily derived by solving the inverse problem of the antenna radiation field. These unique focal field distributions may find potential applications in laser direct writing and optical microscopy, as well as multiple-particle trapping, alignment, and acceleration along the optical axis.

  17. [Focal epithelial hyperplasia].

    PubMed

    Delgado, Yolanda; Torrelo, Antonio; Colmenero, Isabel; Zambrano, Antonio

    2005-12-01

    Focal epithelial hyperplasia (FEH) is a benign proliferation of the oral mucosa with well defined clinical and histological characteristics. It has been associated with infection of the oral mucosa by types 13 and 32 of the human papillomavirus (HPV), and to a lesser extent, with other types. Its clinical course is variable, although it usually persists for months or years; cases with spontaneous resolution have been described, as have others with prolonged persistence. We present the case of an Ecuadorian boy whose visit was motivated by lesions in the oral mucosa consistent with a diagnosis of FEH, which were confirmed in the histological study, and in which HPV type 13 DNA was identified.

  18. Focal adhesions in osteoneogenesis

    PubMed Central

    Biggs, M.J.P; Dalby, M.J

    2010-01-01

    As materials technology and the field of tissue engineering advances, the role of cellular adhesive mechanisms, in particular the interactions with implantable devices, becomes more relevant in both research and clinical practice. A key tenet of medical device technology is to use the exquisite ability of biological systems to respond to the material surface or chemical stimuli in order to help develop next-generation biomaterials. The focus of this review is on recent studies and developments concerning focal adhesion formation in osteoneogenesis, with an emphasis on the influence of synthetic constructs on integrin mediated cellular adhesion and function. PMID:21287830

  19. Extensive focal epithelial hyperplasia.

    PubMed

    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.

  20. Composite focal mechanism for microearthquakes along the northeastern border of the Caribbean plate

    SciTech Connect

    Frankel, A.

    1982-05-01

    Seismograms from a local seismic network in the Virgin Islands portion of the northeastern Caribbean are used to determine a composite focal mechanism for 26 microearthquakes along the North America--Caribbean plate boundary. Only one nodal plane of the focal mechanism could be constrained from P-wave first motion data alone. P/SV amplitude ratios observed for these events were compared to theoretical amplitude ratios calculated for different focal mechanisms. This procedure constrained the dip of the second nodal plane to be shallower than about 50/sup 0/, ruling out the possibility of a transform fault in this portion of the plate boundary. The resulting focal mechanism indicates that oblique underthrusting of the North American plate beneath the Caribbean plate occurs in the area. This oblique motion is accommodated along a thrust plane that dips at a relatively shallow angle beneath the Virgin Islands platform.

  1. Electromyogram-evoked focal myositis

    PubMed Central

    Snipes, George; Quan, Carolyn

    2017-01-01

    Focal myositis is a rarely reported inflammatory disease of skeletal muscle, particularly of an extremity. It is often misinterpreted as an infectious syndrome, leading to prolonged antibiotic use and a delay in immunosuppressive therapy. Without a confirmed etiology to date, we present a case of recurrent focal myositis following an electromyogram. PMID:28127151

  2. Genetics Home Reference: focal dermal hypoplasia

    MedlinePlus

    ... 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 ...

  3. Deep Moonquake Focal Mechanisms: Recovery and Implications

    NASA Technical Reports Server (NTRS)

    Weber, Renee C.; Knapmeyer, Martin

    2012-01-01

    A defining characteristic of deep moonquakes is their tendency to occur with tidal periodicity, prompting previous studies to infer that they are related to the buildup and release of tidal stress within the Moon [refs]. In studies of tidal forcing, a key constraint is the focal mechanism: the fault parameters describing the type of failure moonquakes represent. The quality of the lunar seismic data and the limited source/receiver geometries of the Apollo seismic network prohibit the determination of deep moonquake fault parameters using first-motion polarities, as is typically done in terrestrial seismology [ref]. Without being able to resolve tidal stress onto a known failure plane, we can examine only gross qualities of the tidal stress tensor with respect to moonquake occurrence, so we cannot fully address the role of tidal stress in moonquake generation.

  4. Polarization structuring for focal volume shaping in high-resolution microscopy

    NASA Astrophysics Data System (ADS)

    Iglesias, Ignacio; Vohnsen, Brian

    2007-03-01

    We examined pupil-plane polarization structures for high numerical-aperture objective lenses that generate light distributions at the focal volume similar to those produced by purely radial and azimuthal polarizations. The engineered structures can be dynamically generated with spatial light modulators without the need for additional moving parts in the optical system. Computer simulations show that the method can be considered a valuable addition to the tools available for controlling the interaction of light with matter at the focal region.

  5. Stress tensor and focal mechanisms in the Dead Sea basin

    NASA Astrophysics Data System (ADS)

    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.

  6. Recovery of Deep Moonquake Focal Mechanisms

    NASA Technical Reports Server (NTRS)

    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.

  7. Continuously variable focal length lens

    DOEpatents

    Adams, Bernhard W; Chollet, Matthieu C

    2013-12-17

    A material preferably in crystal form having a low atomic number such as beryllium (Z=4) provides for the focusing of x-rays in a continuously variable manner. The material is provided with plural spaced curvilinear, optically matched slots and/or recesses through which an x-ray beam is directed. The focal length of the material may be decreased or increased by increasing or decreasing, respectively, the number of slots (or recesses) through which the x-ray beam is directed, while fine tuning of the focal length is accomplished by rotation of the material so as to change the path length of the x-ray beam through the aligned cylindrical slows. X-ray analysis of a fixed point in a solid material may be performed by scanning the energy of the x-ray beam while rotating the material to maintain the beam's focal point at a fixed point in the specimen undergoing analysis.

  8. Genetic models of focal epilepsies.

    PubMed

    Boillot, Morgane; Baulac, Stéphanie

    2016-02-15

    Focal epilepsies were for a long time thought to be acquired disorders secondary to cerebral lesions. However, the important role of genetic factors in focal epilepsies is now well established. Several focal epilepsy syndromes are now proven to be monogenic disorders. While earlier genetic studies suggested a strong contribution of ion channel and neurotransmitter receptor genes, later work has revealed alternative pathways, among which the mammalian target of rapamycin (mTOR) signal transduction pathway with DEPDC5. In this article, we provide an update on the mutational spectrum of neuronal nicotinic acetylcholine receptor genes (CHRNA4, CHRNB2, CHRNA2) and KCNT1 causing autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), and of LGI1 in autosomal dominant epilepsy with auditory features (ADEAF). We also emphasize, through a review of the current literature, the contribution of in vitro and in vivo models developed to unveil the pathogenic mechanisms underlying these two epileptic syndromes.

  9. Focal epithelial hyperplasia: Case report.

    PubMed

    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.

  10. Deep Moonquake Focal Mechanisms: Recovery and Implications

    NASA Technical Reports Server (NTRS)

    Knapmeyer, Martin; Weber, Renee C.

    2011-01-01

    A defining characteristic of deep moonquakes is their tendency to occur with tidal periodicity, prompting previous studies to infer that they are related to the buildup and release of tidal stress within the Moon. In studies of tidal forcing, a key constraint is the focal mechanism: the fault parameters describing the type of failure moonquakes represent. The quality of the lunar seismic data and the limited source/receiver geometries of the Apollo seismic network prohibit the determination of deep moonquake fault parameters using first-motion polarities, as is typically done in terrestrial seismology. Without being able to resolve tidal stress onto a known failure plane, we can examine only gross qualities of the tidal stress tensor with respect to moonquake occurrence, so we cannot fully address the role of tidal stress in moonquake generation. We will examine the extent to which shear (S) and compression (P) wave amplitude ratios can constrain moonquake fault geometry by determining whether, for a given cluster, there exists a focal mechanism that can produce a radiation pattern consistent with the amplitudes measured by the Apollo instruments. Amplitudes are read in the ray coordinate frame, directly from seismograms for which the P and S arrivals are clearly identifiable on all long-period channels of the four Apollo stations. We apply an empirical station correction to account for site effects and the differences between P- and S-wave attenuation. Instead of focusing on the best fitting solution only, we formulate the inverse problem using a falsification criterion: all source orientations that do not reproduce the observed SV/P ratios within an error margin derived from the uncertainty of amplitude readings are rejected. All others are accepted as possible solutions. The inversion is carried out using an exhaustive grid search on a regular grid with predefined step size, encompassing all possible combinations of strike, dip and slip. To assess the

  11. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  12. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  13. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  14. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  15. Variable focal length deformable mirror

    DOEpatents

    Headley, Daniel; Ramsey, Marc; Schwarz, Jens

    2007-06-12

    A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.

  16. Focal hyperhidrosis: diagnosis and management

    PubMed Central

    Haider, Aamir; Solish, Nowell

    2005-01-01

    HYPERHIDROSIS, A CONDITION CHARACTERIZED by excessive sweating, can be generalized or focal. Generalized hyperhidrosis involves the entire body and is usually part of an underlying condition, most often an infectious, endocrine or neurologic disorder. Focal hyperhidrosis is idiopathic, occurring in otherwise healthy people. It affects 1 or more body areas, most often the palms, armpits, soles or face. Almost 3% of the general population, largely people aged between 25 and 64 years, experience hyperhidrosis. The condition carries a substantial psychological and social burden, since it interferes with daily activities. However, patients rarely seek a physician's help because many are unaware that they have a treatable medical disorder. Early detection and management of hyperhidrosis can significantly improve a patient's quality of life. There are various topical, systemic, surgical and nonsurgical treatments available with efficacy rates greater than 90%–95%. PMID:15632408

  17. Stigmatic flat focal field spectrograph

    NASA Astrophysics Data System (ADS)

    Niemczyk, T. M.; Gobeli, G. W.

    Advances in two dimensional detectors have created a need for a spectrograph that can produce high fidelity images. Aberrations that detract from image quality in conventional spectrographs are discussed. Ray trace and experimental results obtained for a unique spectrograph designed for use with array detectors, i.e., designed to produce high fidelity images, are presented. The spectrograph employs toroidal mirrors to achieve stigmatic imaging in a flat focal field.

  18. Almost Unilateral Focal Dermal Hypoplasia

    PubMed Central

    Lee, Solam; Choe, Sung Jay

    2017-01-01

    Focal dermal hypoplasia, caused by mutations in PORCN, is an X-linked ectodermal dysplasia, also known as Goltz syndrome. Only seven cases of unilateral or almost unilateral focal dermal hypoplasia have been reported in the English literature and there have been no previously reported cases in the Republic of Korea. A 19-year-old female presented with scalp defects, skin lesions on the right leg and the right trunk, and syndactyly of the right fourth and fifth toes. Cutaneous examination revealed multiple atrophic plaques and a brown and yellow mass with fat herniation and telangiectasia that was mostly located on the lower right leg. She had syndactyly on the right foot and the scalp lesion appeared to be an atrophic, membranous, fibrotic alopecic scar. A biopsy of the calf revealed upper dermal extension of fat cells, dermal atrophy, and loss of dermal collagen. A diagnosis of almost unilateral focal dermal hypoplasia was made on the basis of physical and histologic findings. Henceforth, the patient was referred to a plastic surgeon and an orthopedics department to repair her syndactyly. PMID:28223754

  19. Persistent Focal Behavior and Physical Activity Performance

    ERIC Educational Resources Information Center

    Erfle, Stephen E.

    2014-01-01

    This article examines the proclivity and performance attributes of focal students across time and activities using data from 9,345 students. Three systematic focal behavior partitions are examined: Across activities, across time, and across activities and time. A student's performance is focal if it ends in 0 or 5 for push-ups and 0 for curl-ups.…

  20. Fourier plane imaging microscopy

    SciTech Connect

    Dominguez, Daniel Peralta, Luis Grave de; Alharbi, Nouf; Alhusain, Mdhaoui; Bernussi, Ayrton A.

    2014-09-14

    We show how the image of an unresolved photonic crystal can be reconstructed using a single Fourier plane (FP) image obtained with a second camera that was added to a traditional compound microscope. We discuss how Fourier plane imaging microscopy is an application of a remarkable property of the obtained FP images: they contain more information about the photonic crystals than the images recorded by the camera commonly placed at the real plane of the microscope. We argue that the experimental results support the hypothesis that surface waves, contributing to enhanced resolution abilities, were optically excited in the studied photonic crystals.

  1. Multifocal projection: a multiprojector technique for increasing focal depth.

    PubMed

    Bimber, Oliver; Emmerling, Andreas

    2006-01-01

    In this paper, we describe a novel multifocal projection concept that applies conventional video projectors and camera feedback. Multiple projectors with differently adjusted focal planes, but overlapping image areas are used. They can be either differently positioned in the environment or can be integrated into a single projection unit. The defocus created on an arbitrary surface is estimated automatically for each projector pixel. If this is known, a final image with minimal defocus can be composed in real-time from individual pixel contributions of all projectors. Our technique is independent of the surfaces' geometry, color and texture, the environment light, as well as of the projectors' position, orientation, luminance, and chrominance.

  2. Implementation of focal zooming on the Nike KrF laser.

    PubMed

    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.

  3. Implementation of focal zooming on the Nike KrF laser

    SciTech Connect

    Kehne, D. M.; Karasik, M.; Weaver, J. L.; Chan, Y.; Obenschain, S. P.; Aglitsky, Y.; Smyth, Z.; Lehmberg, R. H.; Terrell, S.

    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.

  4. Focal epithelial hyperplasia: Heck disease.

    PubMed

    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.

  5. Interferon Induced Focal Segmental Glomerulosclerosis

    PubMed Central

    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

  6. Stereo display with time-multiplexed focal adjustment

    PubMed Central

    Hoffman, David M.; Hands, Philip J.W.; Kirby, Andrew K.; Love, Gordon D.; Banks, Martin S.

    2011-01-01

    In stereo displays, binocular disparity creates a striking impression of depth. However, such displays present focus cues—blur and accommodation—that specify a different depth than disparity, thereby causing a conflict. This conflict causes several problems including misperception of the 3D layout, difficulty fusing binocular images, and visual fatigue. To address these problems, we developed a display that preserves the advantages of conventional stereo displays, while presenting correct or nearly correct focus cues. In our new stereo display each eye views a display through a lens that switches between four focal distances at very high rate. The switches are synchronized to the display, so focal distance and the distance being simulated on the display are consistent or nearly consistent with one another. Focus cues for points in-between the four focal planes are simulated by using a depth-weighted blending technique. We will describe the design of the new display, discuss the retinal images it forms under various conditions, and describe an experiment that illustrates the effectiveness of the display in maximizing visual performance while minimizing visual fatigue. PMID:21479104

  7. Analysis of a photonic nanojet assuming a focused incident beam instead of a plane wave

    NASA Astrophysics Data System (ADS)

    Dong, Aotuo; Su, Chin

    2014-12-01

    The analysis of a photonic nanojet formed by dielectric spheres almost always assumes that the incident field is a plane wave. In this work, using vector spherical harmonics representations, we analyze the case of a more realistic incident field consisting of a focused beam formed by a microscope objective. Also included is the situation in which the sphere is not at the focal plane of the focus beam. We find that the dimension of the nanojet beam waist is less sensitive with respect to the azimuthal angle when compared with the plane wave case. Also, by shifting the particle away from the focal plane, the nanojet beam waist can be positioned outside the particle which otherwise would be inside or at the particle surface. Inherently, no such adjustment is possible with an incident plane wave assumption.

  8. Slab buckling and its effect on the distributions and focal mechanisms of deep-focus earthquakes

    NASA Astrophysics Data System (ADS)

    Myhill, R.

    2013-02-01

    This integrated study of deep earthquake locations and focal mechanisms investigates the relationship between the shape of subducting slabs and seismic behaviour in Wadati-Benioff zones. High quality earthquake locations are used to map the shapes of subducting slabs which have reached the upper-lower mantle boundary. The resulting slab models reveal the presence of large slab folds in the mantle transition zone. The distributions and focal mechanisms of deep earthquakes are analysed to determine whether these folds have a role in governing Wadati-Benioff zone seismicity. Bands or lineations of dense seismicity are associated with the hinge zones of identified folds. The focal mechanisms of earthquakes within these bands reveal that the mapped fold hinges are commonly perpendicular to the directions of maximum coseismic extension and compression. The hinges plunge at a variety of angles, resulting in systematic deviations from the downdip stress field expected within planar slabs. Slab synforms are typified by earthquake focal mechanisms indicating in-plane compression (e.g. Izu-Bonin, Tonga), while antiforms have earthquake focal mechanisms indicating in-plane extension (e.g. Solomons) or a mixture of in-plane compression and extension (e.g. Tonga). Slab buckling explains both the clustering of earthquakes and the observed focal mechanism orientations within fold hinges. The localization of strain within buckle zones results in several of the peaks observed in regional earthquake depth distributions. During buckling, the directions of maximum shortening and extension are expected to be perpendicular to the fold hinges, in agreement with deep earthquake moment tensors. Displacement of the minimum-strain surface away from the centre of each seismogenic zone can explain the predominance of in-plane compression within synforms and in-plane extension within antiforms. More complex local variation in focal mechanism orientations in the Tonga slab can be explained by a

  9. Pathogenesis of Focal Segmental Glomerulosclerosis

    PubMed Central

    Lim, Beom Jin; Yang, Jae Won; Do, Woo Sung; Fogo, Agnes B.

    2016-01-01

    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. PMID:27744657

  10. Angle amplifying optics using plane and ellipsoidal reflectors

    DOEpatents

    Glass, Alexander J.

    1977-01-01

    An optical system for providing a wide angle input beam into ellipsoidal laser fusion target illumination systems. The optical system comprises one or more pairs of centrally apertured plane and ellipsoidal mirrors disposed to accept the light input from a conventional lens of modest focal length and thickness, to increase the angular divergence thereof to a value equivalent to that of fast lenses, and to direct the light into the ellipsoidal target illumination system.

  11. Axial Plane Optical Microscopy

    PubMed Central

    Li, Tongcang; Ota, Sadao; Kim, Jeongmin; Wong, Zi Jing; Wang, Yuan; Yin, Xiaobo; Zhang, Xiang

    2014-01-01

    We present axial plane optical microscopy (APOM) that can, in contrast to conventional microscopy, directly image a sample's cross-section parallel to the optical axis of an objective lens without scanning. APOM combined with conventional microscopy simultaneously provides two orthogonal images of a 3D sample. More importantly, APOM uses only a single lens near the sample to achieve selective-plane illumination microscopy, as we demonstrated by three-dimensional (3D) imaging of fluorescent pollens and brain slices. This technique allows fast, high-contrast, and convenient 3D imaging of structures that are hundreds of microns beneath the surfaces of large biological tissues. PMID:25434770

  12. Composite axilens-axicon diffractive optical elements for generation of ring patterns with high focal depth

    NASA Astrophysics Data System (ADS)

    Dharmavarapu, Raghu; Vijayakumar, A.; Brunner, R.; Bhattacharya, Shanti

    2016-03-01

    A binary Fresnel Zone Axilens (FZA) is designed for the infinite conjugate mode and the phase profile of a refractive axicon is combined with it to generate a composite Diffractive Optical Element (DOE). The FZA designed for two focal lengths generates a line focus along the propagation direction extending between the two focal planes. The ring pattern generated by the axicon is focused through this distance and the radius of the ring depends on the propagation distance. Hence, the radius of the focused ring pattern can be tuned, during the design process, within the two focal planes. The integration of the two functions was carried out by shifting the location of zones of FZA with respect to the phase profile of the refractive axicon resulting in a binary composite DOE. The FZAs and axicons were designed for different focal depth values and base angles respectively, in order to achieve different ring radii within the focal depth of each element. The elements were simulated using scalar diffraction formula and their focusing characteristics were analyzed. The DOEs were fabricated using electron beam direct writing and evaluated using a fiber coupled diode laser. The tunable ring patterns generated by the DOEs have prospective applications in microdrilling as well as microfabrication of circular diffractive and refractive optical elements.

  13. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  14. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  15. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  16. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  17. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  18. Precise measurement of planeness.

    PubMed

    Schulz, G; Schwider, J

    1967-06-01

    Interference methods are reviewed-particularly those developed at the German Academy of Sciences in Berlin-with which the deviations of an optically flat surface from the ideal plane can be measured with a high degree of exactness. One aid to achieve this is the relative methods which measure the differences in planeness between two surfaces. These are then used in the absolute methods which determine the absolute planeness of a surface. This absolute determination can be effected in connection with a liquid surface, or (as done by the authors) only by suitable evaluation of relative measurements between unknown plates in various positional combinations. Experimentally, one uses two- or multiple-beam interference fringes of equal thickness(1) or of equal inclination. The fringes are observed visually, scanned, or photographed, and in part several wavelengths or curves of equal density (Aquidensiten) are employed. The survey also brings the following new methods: a relative method, where, with the aid of fringes of superposition, the fringe separation is subdivided equidistantly thus achieving an increase of measuring precision, and an absolute method which determines the deviations of a surface from ideal planeness along arbitrary central sections, without a liquid surface, from four relative interference photographs.

  19. Plane Jane(s).

    ERIC Educational Resources Information Center

    Greenman, Geri

    2001-01-01

    Describes an assignment that was used in an advanced drawing class in which the students created self-portraits, breaking up their images using planes and angles to suggest their bone structure. Explains that the students also had to include three realistic portions in their drawings. (CMK)

  20. Focal epithelial hyperplasia - an update.

    PubMed

    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.

  1. Phase screens for the control of the focal irradiance of the Nova laser

    SciTech Connect

    Lawson, J.K.; Dixit, S.N.; Eimerl, D.; Henesian, M.A.; Manes, K.R.; Morgan, A.J.; Powell, H.T.; Thomas, I.M.; Trenholme, J.B.; Woods, B.W.

    1993-09-17

    The authors report on the design and fabrication of continuous contour (kinoform) phase plates for homogenizing the focal plane irradiance of high-power, inertial confinement fusion laser systems. These kinoform phase plates are designed using an iterative algorithm. They offer the flexibility of controlling the overall shape of the far-field irradiance profile and the ability to concentrate the energy within a central region of the focal profile. These properties make kinoforms superior to the conventional, binary random phase plates for many applications. Potential methods for fabrication of such kinoform phase plates are discussed.

  2. Parameter Plane Design Method

    DTIC Science & Technology

    1989-03-01

    Th usr a toente aninteer a thca sms b esta 1 Fp-ocsing 2. Enter P1 values, lwgt, ldig - > 9 Table I give us proper values. Table 1. PARAMETER TABLE...necessary and identify by block number) In this thesis a control systems analysis package is developed using parameter plane methods. It is an interactive...designer is able to choose values of the parameters which provide a good compromise between cost and dynamic behavior. 20 Distribution Availability of

  3. Thermally induced changes in the focal distance of composite mirrors - Composites with a zero coefficient of thermal expansion of the radius of curvature

    NASA Technical Reports Server (NTRS)

    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.

  4. Focal liver lesions found incidentally

    PubMed Central

    Algarni, Abdullah A; Alshuhri, Abdullah H; Alonazi, Majed M; Mourad, Moustafa Mabrouk; Bramhall, Simon R

    2016-01-01

    Incidentally found focal liver lesions are a common finding and a reason for referral to hepatobiliary service. They are often discovered in patients with history of liver cirrhosis, colorectal cancer, incidentally during work up for abdominal pain or in a trauma setting. Specific points should considered during history taking such as risk factors of liver cirrhosis; hepatitis, alcohol consumption, substance exposure or use of oral contraceptive pills and metabolic syndromes. Full blood count, liver function test and tumor markers can act as a guide to minimize the differential diagnosis and to categorize the degree of liver disease. Imaging should start with B-mode ultrasound. If available, contrast enhanced ultrasound is a feasible, safe, cost effective option and increases the ability to reach a diagnosis. Contrast enhanced computed tomography should be considered next. It is more accurate in diagnosis and better to study anatomy for possible operation. Contrast enhanced magnetic resonance is the gold standard with the highest sensitivity. If doubt still remains, the options are biopsy or surgical excision. PMID:27028805

  5. Focal brain inflammation and autism.

    PubMed

    Theoharides, Theoharis C; Asadi, Shahrzad; Patel, Arti B

    2013-04-09

    Increasing evidence indicates that brain inflammation is involved in the pathogenesis of neuropsychiatric diseases. Autism spectrum disorders (ASD) are characterized by social and learning disabilities that affect as many as 1/80 children in the USA. There is still no definitive pathogenesis or reliable biomarkers for ASD, thus significantly curtailing the development of effective therapies. Many children with ASD regress at about age 3 years, often after a specific event such as reaction to vaccination, infection, stress or trauma implying some epigenetic triggers, and may constitute a distinct phenotype. ASD children respond disproportionally to stress and are also affected by food and skin allergies. Corticotropin-releasing hormone (CRH) is secreted under stress and together with neurotensin (NT) stimulates mast cells and microglia resulting in focal brain inflammation and neurotoxicity. NT is significantly increased in serum of ASD children along with mitochondrial DNA (mtDNA). NT stimulates mast cell secretion of mtDNA that is misconstrued as an innate pathogen triggering an auto-inflammatory response. The phosphatase and tensin homolog (PTEN) gene mutation, associated with the higher risk of ASD, which leads to hyper-active mammalian target of rapamycin (mTOR) signalling that is crucial for cellular homeostasis. CRH, NT and environmental triggers could hyperstimulate the already activated mTOR, as well as stimulate mast cell and microglia activation and proliferation. The natural flavonoid luteolin inhibits mTOR, mast cells and microglia and could have a significant benefit in ASD.

  6. Early vision and focal attention

    NASA Astrophysics Data System (ADS)

    Julesz, Bela

    1991-07-01

    At the thirty-year anniversary of the introduction of the technique of computer-generated random-dot stereograms and random-dot cinematograms into psychology, the impact of the technique on brain research and on the study of artificial intelligence is reviewed. The main finding-that stereoscopic depth perception (stereopsis), motion perception, and preattentive texture discrimination are basically bottom-up processes, which occur without the help of the top-down processes of cognition and semantic memory-greatly simplifies the study of these processes of early vision and permits the linking of human perception with monkey neurophysiology. Particularly interesting are the unexpected findings that stereopsis (assumed to be local) is a global process, while texture discrimination (assumed to be a global process, governed by statistics) is local, based on some conspicuous local features (textons). It is shown that the top-down process of "shape (depth) from shading" does not affect stereopsis, and some of the models of machine vision are evaluated. The asymmetry effect of human texture discrimination is discussed, together with recent nonlinear spatial filter models and a novel extension of the texton theory that can cope with the asymmetry problem. This didactic review attempts to introduce the physicist to the field of psychobiology and its problems-including metascientific problems of brain research, problems of scientific creativity, the state of artificial intelligence research (including connectionist neural networks) aimed at modeling brain activity, and the fundamental role of focal attention in mental events.

  7. Finger-specific loss of independent control of movements in musicians with focal dystonia.

    PubMed

    Furuya, S; Altenmüller, E

    2013-09-05

    The loss of independent control of finger movements impairs the dexterous use of the hand. Focal hand dystonia is characterised by abnormal structural and functional changes at the cortical and subcortical regions responsible for individuated finger movements and by the loss of surround inhibition in the finger muscles. However, little is known about the pathophysiological impact of focal dystonia on the independent control of finger movements. Here we addressed this issue by asking pianists with and without focal dystonia to repetitively strike a piano key with one of the four fingers as fast as possible while the remaining digits kept the adjacent keys depressed. Using principal component analysis and cluster analysis to the derived keystroke data, we successfully classified pianists according to the presence or absence of dystonic symptoms with classification rates and cross-validation scores of approximately 90%. This confirmed the effects of focal dystonia on the individuated finger movements. Interestingly, the movement features that contributed to successful classification differed across fingers. Compared to healthy pianists, pianists with an affected index finger were characterised predominantly by stronger keystrokes, whereas pianists with affected middle or ring fingers exhibited abnormal temporal control of the keystrokes, such as slowness and rhythmic inconsistency. The selective alternation of the movement features indicates a finger-specific loss of the independent control of finger movements in focal dystonia of musicians.

  8. Analysis of Altered Micro RNA Expression Profiles in Focal Cortical Dysplasia IIB.

    PubMed

    Li, Lin; Liu, Chang-Qing; Li, Tian-Fu; Guan, Yu-Guang; Zhou, Jian; Qi, Xue-Ling; Yang, Yu-Tao; Deng, Jia-Hui; Xu, Zhi-Qing David; Luan, Guo-Ming

    2016-04-01

    Focal cortical dysplasia type IIB is a commonly encountered subtype of developmental malformation of the cerebral cortex and is often associated with pharmacoresistant epilepsy. In this study, to investigate the molecular etiology of focal cortical dysplasia type IIB, the authors performed micro ribonucleic acid (RNA) microarray on surgical specimens from 5 children (2 female and 3 male, mean age was 73.4 months, range 50-112 months) diagnosed of focal cortical dysplasia type IIB and matched normal tissue adjacent to the lesion. In all, 24 micro RNAs were differentially expressed in focal cortical dysplasia type IIB, and the microarray results were validated using quantitative real-time polymerase chain reaction (PCR). Then the putative target genes of the differentially expressed micro RNAs were identified by bioinformatics analysis. Moreover, biological significance of the target genes was evaluated by investigating the pathways in which the genes were enriched, and the Hippo signaling pathway was proposed to be highly related with the pathogenesis of focal cortical dysplasia type IIB.

  9. Dual Common Planes for Time Multiplexing of Dual-Color QWIPs

    NASA Technical Reports Server (NTRS)

    Rafol, Sir B.; Gunapala, Srath; Bandara, Sumith; Liu, John; Mumolo, Jason

    2006-01-01

    A proposed improved method of externally controlled time multiplexing of the readouts of focal-plane arrays of pairs of stacked quantum-well infrared photodetectors (QWIPs) that operate in different wavelength bands is based on a dual-detector-common-plane circuit configuration. The method would be implemented in a QWIP integrated-circuit chip hybridized with a readout integrated-circuit (ROIC) chip.

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

    NASA Technical Reports Server (NTRS)

    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.

  11. The Aerodynamic Plane Table

    NASA Technical Reports Server (NTRS)

    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.

  12. Fourier plane image amplifier

    DOEpatents

    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.

  13. Fourier plane image amplifier

    DOEpatents

    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.

  14. Do focal colors look particularly "colorful"?

    PubMed

    Witzel, Christoph; Franklin, Anna

    2014-04-01

    If the most typical red, yellow, green, and blue were particularly colorful (i.e., saturated), they would "jump out to the eye." This would explain why even fundamentally different languages have distinct color terms for these focal colors, and why unique hues play a prominent role in subjective color appearance. In this study, the subjective saturation of 10 colors around each of these focal colors was measured through a pairwise matching task. Results show that subjective saturation changes systematically across hues in a way that is strongly correlated to the visual gamut, and exponentially related to sensitivity but not to focal colors.

  15. Unilateral Isolated Proximal Femoral Focal Deficiency

    PubMed Central

    Doğer, Emek; Köpük, Şule Y.; Çakıroğlu, Yiğit; Çakır, Özgür; Yücesoy, Gülseren

    2013-01-01

    Objective. To discuss a patient with a prenatal diagnosis of unilateral isolated femoral focal deficiency. Case. Antenatal diagnosis of unilateral isolated femoral focal deficiency was made at 20 weeks of gestation. The length of left femur was shorter than the right, and fetal femur length was below the fifth percentile. Proximal femoral focal deficiency was diagnosed. After delivery, the diagnosis was confirmed with skeletal radiographs and magnetic resonance imaging. In prenatal ultrasonographic examination, the early recognition and exclusion of skeletal dysplasias is important; moreover, treatment plans should be initiated, and valuable information should be provided to the family. PMID:23984135

  16. Optical design of the post-focal relay of MAORY

    NASA Astrophysics Data System (ADS)

    Lombini, M.; De Rosa, A.; Ciliegi, P.; Cortecchia, F.; Diolaiti, E.; Patti, Mauro; Bonaglia, M.; Busoni, L.; De Caprio, V.; Esposito, S.; Feautrier, P.; Rabou, P.; Riva, M.; Stadler, E.

    2016-08-01

    The Multi Conjugate Adaptive Optics RelaY (MAORY) for the European Extremely Large Telescope is planned to be located on the straight-through port of the telescope Nasmyth platform and shall re-image the telescope focal plane to a wide field camera (MICADO) and a possible future second instrument. By means of natural and artificial (laser) reference sources for wavefront sensing, and of deformable mirrors for wavefront correction, MAORY shall be able to compensate the wavefront disturbances affecting the scientific observations, achieving high Strehl ratio and high sky coverage. A trade-off study among different design options has been carried out addressing optical performance at the exit ports (wave front error, field distortion, throughput), structure stability, interface constraints (mass, size, location and accessibility of the two client instruments), and the overall adaptive optics performance. We discuss the baseline configuration of the opto-mechanical design.

  17. Characterization of the Coupling Between Adjacent Finite Ground Coplanar (FGC) Waveguides

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Katehi, Linda P. B.; Tentzeris, Emmanouil M.

    1997-01-01

    Coupling between adjacent Finite Ground Coplanar (FGC) waveguides as a function of the line geometry is presented for the first time. A two Dimension-Finite Difference Time Domain (2D-FDTD) analysis and measurements are used to show that the coupling decreases as the line to line separation and the grOUnd plane width increases. Furthermore, it is shown that for a given spacing between the center lines of two FGC lines, the coupling is lower if the ground plane width is smaller Lastly, electric field plots generated from the 2D-FDTD technique are presented which demonstrate a strong slotline mode is established in the coupled FGC line.

  18. On the time-course of adjacent and non-adjacent transposed-letter priming

    PubMed Central

    Ktori, Maria; Kingma, Brechtsje; Hannagan, Thomas; Holcomb, Phillip J.; Grainger, Jonathan

    2014-01-01

    We compared effects of adjacent (e.g., atricle-ARTICLE) and non-adjacent (e.g., actirle-ARTICLE) transposed-letter (TL) primes in an ERP study using the sandwich priming technique. TL priming was measured relative to the standard double-substitution condition. We found significantly stronger priming effects for adjacent transpositions than non-adjacent transpositions (with 2 intervening letters) in behavioral responses (lexical decision latencies), and the adjacent priming effects emerged earlier in the ERP signal, at around 200 ms post-target onset. Non-adjacent priming effects emerged about 50 ms later and were short-lived, being significant only in the 250-300 ms time-window. Adjacent transpositions on the other hand continued to produce priming in the N400 time-window (300-500 ms post-target onset). This qualitatively different pattern of priming effects for adjacent and non-adjacent transpositions is discussed in the light of different accounts of letter transposition effects, and the utility of drawing a distinction between positional flexibility and positional noise. PMID:25364497

  19. Infrared imaging of cotton fibers using a focal-plane array detector

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vibrational spectroscopy studies can be used to examine the quality and structure of cotton fibers. An emerging area of research relates to the imaging of cotton fibers. Herein, we report the use of a Fourier-transform infrared (FTIR) microscope to image developing cotton fibers. Studies were perfor...

  20. A High-Energy Focal-Plane Gas Scintillation Proportional Counter

    NASA Technical Reports Server (NTRS)

    Ramsey, B. D.; Austin, R. A.; Apple, J. A.; Dietz, K. L.

    1999-01-01

    We have developed a high-pressure Gas Scintillation Proportional Counter (GSPC) for the focus of a hard-x-ray telescope. It features an absorption region 50 mm in diameter and 50 mm deep, filled with Xenon + 4% He at 10(exp 6) Pa total pressure, which gives useful response (greater than 75% efficiency) up to the mirror cut-off of 70 keV. Tests with a prototype unit show an energy resolution of 3.5% at 60 keV and a spatial resolution of 0.35 mm from 30-50 keV. Two flight units are currently under construction for a balloon flight in September 1999. Full details of their design and performance will be presented together with available quick-look background data from the flight.

  1. Flagging and correction of pattern noise in the Kepler focal plane array

    NASA Astrophysics Data System (ADS)

    Kolodziejczak, Jeffery J.; Caldwell, Douglas A.; Van Cleve, Jeffery E.; Clarke, Bruce D.; Jenkins, Jon M.; Cote, Miles T.; Klaus, Todd C.; Argabright, Vic S.

    2010-07-01

    In order for Kepler to achieve its required <20 PPM photometric precision for magnitude 12 and brighter stars, instrument-induced variations in the CCD readout bias pattern (our "2D black image"), which are either fixed or slowly varying in time, must be identified and the corresponding pixels either corrected or removed from further data processing. The two principle sources of these readout bias variations are crosstalk between the 84 science CCDs and the 4 fine guidance sensor (FGS) CCDs and a high frequency amplifier oscillation on <40% of the CCD readout channels. The crosstalk produces a synchronous pattern in the 2D black image with time-variation observed in <10% of individual pixel bias histories. We will describe a method of removing the crosstalk signal using continuously-collected data from masked and over-clocked image regions (our "collateral data"), and occasionally-collected full-frame images and reverse-clocked readout signals. We use this same set to detect regions affected by the oscillating amplifiers. The oscillations manifest as time-varying moiré pattern and rolling bands in the affected channels. Because this effect reduces the performance in only a small fraction of the array at any given time, we have developed an approach for flagging suspect data. The flags will provide the necessary means to resolve any potential ambiguity between instrument-induced variations and real photometric variations in a target time series. We will also evaluate the effectiveness of these techniques using flight data from background and selected target pixels.

  2. Military Applications of Curved Focal Plane Arrays Developed by the HARDI Program

    DTIC Science & Technology

    2011-01-01

    considered one of the main founders of geometrical optics, modern photography, and cinematography . Among his inventions are the Petzval portrait lens... special frequencies, (b) the variation of intensity as a function of special frequency, (c) the image variation of intensity as a result of an...parameters for the HARDI systems to be designed for various applications. To do this, we needed a toolcomputer codeto study the effects of various

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

    NASA Astrophysics Data System (ADS)

    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.

  4. Progress in development of H4RG-10 infrared focal plane arrays for WFIRST-AFTA

    NASA Astrophysics Data System (ADS)

    Piquette, Eric C.; McLevige, William; Auyeung, John; Wong, Andre

    2014-07-01

    We describe progress in the development and demonstration of Teledyne's new high resolution large format FPA for astronomy, the H4RG-10 IR. The H4RG-10 is the latest in Teledyne's H×RG line of sensors, in a 4096×4096 format using 10 micron pixels. It is offered as a hybrid sensor using either a silicon p-i-n detector array (HyViSI) or a HgCdTe photodiode array with standard infrared cutoff wavelength of 1.75μm, 2.5μm, or 5.3μm (with custom cutoff wavelengths also available). The HgCdTe sensor arrays are fully substrate removed to provide high quantum efficiency, response to visible wavelengths, and minimize cosmic ray and fringing mitigation. Packaging using either CE6 or SiC bases is available. Teledyne is currently fabricating H4RG-10 SWIR FPAs for NASA's WFIRST space telescope instrument. Initial array performance has been tested and will be presented. Key results include the demonstration of low dark current (array mean dark current of <0.01e-/s/pixel at 100K), low noise (<10 e-/CDS read noise), and high array operability (>99% pixels). The paper discusses the sensor configuration and features, the performance achieved to date including QE, dark current, noise maps and histograms, and the remaining challenges.

  5. The Constellation-X Focal Plane Microcalorimeter Array: An NTD-Germanium Solution

    NASA Technical Reports Server (NTRS)

    Beeman, J.; Silver, E.; Bandler, S.; Schnopper, H.; Murray, S.; Madden, N.; Landis, D.; Haller, E. E.; Barbera, M.

    2001-01-01

    The hallmarks of Neutron Transmutation Doped (NTD) germanium cryogenic thermistors include high reliability, reproducibility, and long term stability of bulk carrier transport properties. Using micro-machined NTD Ge thermistors with integral 'flying' leads, we can now fabricate two-dimensional arrays that are built up from a series of stacked linear arrays. We believe that this modular approach of building, assembling, and perhaps replacing individual modules of detectors is essential to the successful fabrication and testing of large multi-element instruments. Details of construction are presented.

  6. Si:Ga focal plane arrays for satellite and ground-based telescopes

    NASA Astrophysics Data System (ADS)

    Mottier, P.; Agnese, P.; Lagage, P. O.

    1991-09-01

    A brief description of IR sensor devices for astronomical observation in the 4-17 micron wavelength band using Si:Ga detectors is given. These devices are to equip ISOCAM, a camera which will operate from the Infrared Space Observatory, the European satellite expected to be launched in May 1993, and C10-mu, a French astronomical camera based at the Canadian French Hawaii Telescope. These sensor devices are polylithic dies: the photoconductor array is hybridized by indium bumps to the readout circuit. Reliability tests show that neither thermal cycles nor strong acceleration or vibrations degrade the mechanical behavior of such a structure. A comparison between ISOCAM and the C10-mu detector is presented in tabular form.

  7. Intensified-CCD focal plane detector for space applications A second generation

    NASA Technical Reports Server (NTRS)

    Torr, M. R.; Torr, D. G.; Baum, R.; Spielmaker, R.

    1986-01-01

    An intensified-CCD detector system developed for space applications from commercially available components is described. This detector uses components which are readily available and are mechanically, thermally, and optically coupled to produce the final compact system. The CCD is cooled using a Peltier-effect thermoelectric cooler to reduce thermal noise. The image is formed on the photocathode of a proximity-focused image intensifier and is transferred fiber-optically from the intensifier to the CDD. Various photocathode and window materials are used to optimize the system for use within the wavelength range extending from the far UV to the near IR. The basic design, including the image intensifier, intensifier-CCD interface, CCD array, cooling, electronics, and mounting, and the detector performance are described in detail.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Segmentation of Three Dimensional Cell Culture Models from aSingle Focal Plane

    SciTech Connect

    Chang, Hang; Parvin, Bahram

    2006-11-01

    Three dimensional cell culture models offer new opportunities for development of computational techniques for segmentation and localization. These assays have a unique signature of a clump of cells that correspond to a functioning colony. Often the nuclear compartment is labeled and then imaged with fluorescent microscopy to provide context for protein localization. These colonies are first delineated from background using the level set method. Within each colony, nuclear regions are then bounded by their center of mass through radial voting, and a local neighborhood for each nucleus is established through Voronoi tessellation. Finally, the level set method is applied again within each Voronoi region to delineate the nuclear compartment. The paper concludes with the application of the proposed method to a dataset of experimental data demonstrating a stable solution when iterative radial voting and level set methods are used synergistically.

  10. An Indium Gallium Arsenide Visible/SWIR Focal Plane Array for Low Light Level Imaging

    NASA Technical Reports Server (NTRS)

    Cohen, Marshall J.; Ettenberg, Martin H.; Lange, Michael J.; Olsen, Gregory H.

    1999-01-01

    PIN photodiodes fabricated from indium gallium arsenide lattice-matched to indium phosphide substrates (In(.53)Ga(.47)As/InP) exhibit low reverse saturation current densities (JD < 10(exp -8) A/sq cm), and high shunt resistance-area products (RoA > 10(exp 6) omega-sq cm) at T=290K. Backside-illuminated, hybrid-integrated InGaAs FPAs are sensitive from 0.9 micrometers to 1.7 micrometers. 290K detectivities, D(*), greater than 10(exp 14) cm-(square root of Hz/W) are demonstrated. This represents the highest room temperature detectivity of any infrared material. The long wavelength cutoff (1.7 micrometers) makes In(.53)Ga(.47)As an idea match to the available airglow that has major peaks at 1.3 micrometers and 1.6 micrometers. The short wavelength 'cut-on' at 0.9 micrometers is due to absorption in the InP substrate. We will report on new InGaAs FPA epitaxial structures and processing techniques. These have resulted in improved performance in the form of a 10 x increase in detectivity and visible response via removal of the InP substrate. The resulting device features visible and SWIR response with greater than 15% quantum efficiency at 0.5 micrometers while maintaining the long wavelength cutoff. Imaging has been demonstrated under overcast starlight/urban glow conditions with cooling provided by a single stage thermoelectric cooler. Details on the material structure and device fabrication, quantitative characterization of spectral response and detectivity, as well as examples of night vision imagery are presented.

  11. Buffer direct injection readout integrated circuit design for dual band infrared focal plane array detector

    NASA Astrophysics Data System (ADS)

    Sun, Tai-Ping; Lu, Yi-Chuan; Shieh, Hsiu-Li; Tang, Shiang-Feng; Lin, Wen-Jen

    2013-05-01

    This paper proposes dual-mode buffer direct injection (BDI) and direct injection (DI) readout circuit design. The DI readout circuit has the advantage of being a simple circuit, requiring a small layout area, and low power consumption. The internal resistance of the photodetector will affect the photocurrent injection efficiency. We used a buffer amplifier to design the BDI readout circuit since it would reduce the input impedance and raise the injection efficiency. This paper will discuss and analyze the power consumption, injection efficiency, layout area, and circuit noise. The circuit is simulated using a TSMC 0.35 um Mixed Signal 2P4M CMOS 5 V process. The dimension of the pixel area is 30×30 μm. We have designed a 10×8 array for the readout circuit of the interlaced columns. The input current ranges from 1 nA to 10 nA, when the measurement current is 10 pA to 10 nA. The integration time was varied. The circuit output swing was 2 V. The total root mean square noise voltage was 4.84 mV. The signal to noise ratio was 52 dB, and the full chip circuit power consumption was 9.94 mW.

  12. An abuttable CCD imager for visible and X-ray focal plane arrays

    NASA Technical Reports Server (NTRS)

    Burke, Barry E.; Mountain, Robert W.; Harrison, David C.; Bautz, Marshall W.; Doty, John P.

    1991-01-01

    A frame-transfer silicon charge-coupled-device (CCD) imager has been developed that can be closely abutted to other imagers on three sides of the imaging array. It is intended for use in multichip arrays. The device has 420 x 420 pixels in the imaging and frame-store regions and is constructed using a three-phase triple-polysilicon process. Particular emphasis has been placed on achieving low-noise charge detection for low-light-level imaging in the visible and maximum energy resolution for X-ray spectroscopic applications. Noise levels of 6 electrons at 1-MHz and less than 3 electrons at 100-kHz data rates have been achieved. Imagers have been fabricated on 1000-Ohm-cm material to maximize quantum efficiency and minimize split events in the soft X-ray regime.

  13. Flagging and Correction of Pattern Noise in the Kepler Focal Plane Array

    NASA Technical Reports Server (NTRS)

    Kolodziejczak, Jeffery J.; Caldwell, Douglas A.; VanCleve, Jeffrey E.; Clarke, Bruce D.; Jenkins, Jon M.; Cote, Miles T.; Klaus, Todd C.; Argabright, Vic S.

    2010-01-01

    In order for Kepler to achieve its required less than 20 PPM photometric precision for magnitude 12 and brighter stars, instrument-induced variations in the CCD readout bias pattern (our "2D black image"), which are either fixed or slowly varying in time, must be identified and the corresponding pixels either corrected or removed from further data processing. The two principle sources of these readout bias variations are crosstalk between the 84 science CCDs and the 4 fine guidance sensor (FGS) CCDs and a high frequency amplifier oscillation on less than 40% of the CCD readout channels. The crosstalk produces a synchronous pattern in the 2D black image with time-variation observed in less than 10% of individual pixel bias histories. We will describe a method of removing the crosstalk signal using continuously-collected data from masked and over-clocked image regions (our "collateral data"), and occasionally-collected full-frame images and reverse-clocked readout signals. We use this same set to detect regions affected by the oscillating amplifiers. The oscillations manifest as time-varying moir pattern and rolling bands in the affected channels. Because this effect reduces the performance in only a small fraction of the array at any given time, we have developed an approach for flagging suspect data. The flags will provide the necessary means to resolve any potential ambiguity between instrument-induced variations and real photometric variations in a target time series. We will also evaluate the effectiveness of these techniques using flight data from background and selected target pixels.

  14. HgCdTe heterostructures on Si (310) substrates for midinfrared focal plane arrays

    SciTech Connect

    Yakushev, M. V. Brunev, D. V.; Varavin, V. S.; Vasilyev, V. V.; Dvoretskii, S. A.; Marchishin, I. V.; Predein, A. V.; Sabinina, I. V.; Sidorov, Yu. G.; Sorochkin, A. V.

    2011-03-15

    Results of studies of the molecular beam epitaxial growth of HgCdTe alloys on Si substrates as large as 100 mm in diameter are presented. Optimum conditions for obtaining HgCdTe/Si(310) heterostructures of the device quality for the spectral range of 3-5 {mu}m are determined. The results of measurements and discussion of photoelectric parameters of an infrared photodetector of a format of 320 Multiplication-Sign 256 elements with a step of 30 {mu}m based on a hybrid assembly of a matrix photosensitive cell with a Si multiplexer are presented. A high stability of photodetector parameters to thermocycling from room temperature to liquid-nitrogen temperature is shown.

  15. Focal Plane Detectors for the Advanced Gamma-Ray Imaging System (AGIS)

    SciTech Connect

    Otte, A. N.; Williams, D. A.; Byrum, K.; Drake, G.; Horan, D.; Smith, A.; Wagner, R. G.; Falcone, A.; Funk, S.; Tajima, H.; Mukherjee, R.

    2008-12-24

    The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation observatory in ground-based very high energy gamma-ray astronomy. Design goals are ten times better sensitivity, higher angular resolution, and a lower energy threshold than existing Cherenkov telescopes. Simulations show that a substantial improvement in angular resolution may be achieved if the pixel diameter is reduced to the order of 0.05 deg, i.e. two to three times smaller than the pixel diameter of current Cherenkov telescope cameras. At these dimensions, photon detectors with smaller physical dimensions can be attractive alternatives to the classical photomultiplier tube (PMT). Furthermore, the operation of an experiment with the size of AGIS requires photon detectors that are among other things more reliable, more durable, and possibly higher efficiency photon detectors. Alternative photon detectors we are considering for AGIS include both silicon photomultipliers (SiPMs) and multi-anode photomultipliers (MAPMTs). Here we present results from laboratory testing of MAPMTs and SiPMs along with results from the first incorporation of these devices into cameras on test bed Cherenkov telescopes.

  16. Thermal Imaging with Novel Infrared Focal Plane Arrays and Quantitative Analysis of Thermal Imagery

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Rafol, S. B.; Bandara, S. V.; Liu, J. K.; Mumolo, J. M.; Soibel, A.; Ting, D. Z.; Tidrow, Meimei

    2012-01-01

    We have developed a single long-wavelength infrared (LWIR) quantum well infrared photodetector (QWIP) camera for thermography. This camera has been used to measure the temperature profile of patients. A pixel coregistered simultaneously reading mid-wavelength infrared (MWIR)/LWIR dual-band QWIP camera was developed to improve the accuracy of temperature measurements especially with objects with unknown emissivity. Even the dualband measurement can provide inaccurate results due to the fact that emissivity is a function of wavelength. Thus we have been developing a four-band QWIP camera for accurate temperature measurement of remote object.

  17. Broadband and multi-color large format infrared focal plane arrays for static imaging interferometers

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Rafol, S. B.; Mumolo, J. M.; Reininger, F. M.; Fastenau, J. M.; Liu, A. K.

    2001-01-01

    In this presentation, we will discuss the development of this large format broadband infrared FPA based on a GaAs/AlGaAs materials system and its performance in quantum efficiency, noise equivalent differential temperature, uniformity, and operability.

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

    NASA Technical Reports Server (NTRS)

    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.

  19. Real-time, continuous-wave terahertz imaging using a microbolometer focal-plane array

    NASA Technical Reports Server (NTRS)

    Hu, Qing (Inventor); Min Lee, Alan W. (Inventor)

    2010-01-01

    The present invention generally provides a terahertz (THz) imaging system that includes a source for generating radiation (e.g., a quantum cascade laser) having one or more frequencies in a range of about 0.1 THz to about 10 THz, and a two-dimensional detector array comprising a plurality of radiation detecting elements that are capable of detecting radiation in that frequency range. An optical system directs radiation from the source to an object to be imaged. The detector array detects at least a portion of the radiation transmitted through the object (or reflected by the object) so as to form a THz image of that object.

  20. Real-Time Terahertz Imaging Using a Quantum Cascade Laser and Uncooled Microbolometer Focal Plane Array

    DTIC Science & Technology

    2008-06-01

    1] D. Arnone, C. Ciesla, and M. Pepper , “Terahertz imaging comes into view,” Physics World 4, 35-40 (2000). [2] D. M. Mittleman, M. Gupta, R...of the 26th Annu. Int. Conf. of the IEEE (IEEE, 2004), pp. 1302-1305. [16] B. Ferguson , S. Wang, D. Gray, D. Abbott and X. -C. Zhang...using Kirchhoff migration," Opt. Lett. 26, 1513-1515 (2001). [30] B. Ferguson , S. Wang, D. Gray, D. Abbot, and X.-C. Zhang, "T-ray computed

  1. Further Developments in Improved Sensitivity, Low-cost Uncooled IR Detector Focal Plane Arrays

    DTIC Science & Technology

    2010-11-01

    spin coating . .......................................................................................................................................7...acid functionalized BaTiO3 nanoparticles on PtTi/Si substrates using spin coating and drop casting. ARL Achieved integration of electrical contacts...inert gas flow. The system is currently under testing. Figure 6. SEM images of BaTiO3 films featuring 210 nm thickness prepared by spin coating .

  2. Real-time nonlinear correction of back-focal-plane detection in optical tweezers

    SciTech Connect

    Aggarwal, Tanuj; Salapaka, Murti

    2010-12-15

    Photodiode based detection of laser trapped beads using forward scattered light is a frequently employed technique for position measurement. There is a nonlinear relationship between photodiode outputs and bead position but for small displacements linear approximation holds well. Traditionally, the nonlinearity is compensated by normalizing the photodiode's position signal with the intensity signal and then using a polynomial fit in the range where voltage to position mapping is one to one. In this article, this range is extended by using the intensity signal as an independent input along with the two position signals. A map from the input signals to the actual position values is obtained. This mapping is one-to-one for a larger range that results in an increased detection range. An artificial neural network that facilitates implementation is employed for this purpose. This scheme is implemented on a Field Programmable Gate Array based data acquisition and control hardware with closed loop bandwidth of 50 kHz. Detection of the order of 350 nm from the center of detection laser is demonstrated for a 500 nm diameter bead compared to 180 nm achieved by a polynomial fit.

  3. Shaped pupil Lyot coronagraphs: high-contrast solutions for restricted focal planes

    NASA Astrophysics Data System (ADS)

    Zimmerman, Neil T.; Eldorado Riggs, A. J.; Jeremy Kasdin, N.; Carlotti, Alexis; Vanderbei, Robert J.

    2016-01-01

    Coronagraphs of the apodized pupil and shaped pupil varieties use the Fraunhofer diffraction properties of amplitude masks to create regions of high contrast in the vicinity of a target star. Here we present a hybrid coronagraph architecture in which a binary, hard-edged shaped pupil mask replaces the gray, smooth apodizer of the apodized pupil Lyot coronagraph (APLC). For any contrast and bandwidth goal in this configuration, as long as the prescribed region of contrast is restricted to a finite area in the image, a shaped pupil is the apodizer with the highest transmission. We relate the starlight cancellation mechanism to that of the conventional APLC. We introduce a new class of solutions in which the amplitude profile of the Lyot stop, instead of being fixed as a padded replica of the telescope aperture, is jointly optimized with the apodizer. Finally, we describe shaped pupil Lyot coronagraph (SPLC) designs for the baseline architecture of the Wide-Field Infrared Survey Telescope-Astrophysics Focused Telescope Assets (WFIRST-AFTA) coronagraph. These SPLCs help to enable two scientific objectives of the WFIRST-AFTA mission: (1) broadband spectroscopy to characterize exoplanet atmospheres in reflected starlight and (2) debris disk imaging.

  4. Spectral Analysis of the Primary Flight Focal Plane Arrays for the Thermal Infrared Sensor

    NASA Technical Reports Server (NTRS)

    Montanaro, Matthew; Reuter, Dennis C.; Markham, Brian L.; Thome, Kurtis J.; Lunsford, Allen W.; Jhabvala, Murzy D.; Rohrbach, Scott O.; Gerace, Aaron D.

    2011-01-01

    Thermal Infrared Sensor (TIRS) is a (1) New longwave infrared (10 - 12 micron) sensor for the Landsat Data Continuity Mission, (2) 185 km ground swath; 100 meter pixel size on ground, (3) Pushbroom sensor configuration. Issue of Calibration are: (1) Single detector -- only one calibration, (2) Multiple detectors - unique calibration for each detector -- leads to pixel-to-pixel artifacts. Objectives are: (1) Predict extent of residual striping when viewing a uniform blackbody target through various atmospheres, (2) Determine how different spectral shapes affect the derived surface temperature in a realistic synthetic scene.

  5. Fabrication of a Cryogenic Terahertz Emitter for Bolometer Focal Plane Calibrations

    NASA Technical Reports Server (NTRS)

    Chervenak, James; Brown, Ari; Wollack, Edward

    2012-01-01

    A fabrication process is reported for prototype emitters of THz radiation, which operate cryogenically, and should provide a fast, stable blackbody source suitable for characterization of THz devices. The fabrication has been demonstrated and, at the time of this reporting, testing was underway. The emitter is similar to a monolithic silicon bolometer in design, using both a low-noise thermometer and a heater element on a thermally isolated stage. An impedance-matched, high-emissivity coat ing is also integrated to tune the blackbody properties. This emitter is designed to emit a precise amount of power as a blackbody spectrum centered on terahertz frequencies. The emission is a function of the blackbody temperature. An integrated resistive heater and thermometer system can control the temperature of the blackbody with greater precision than previous incarnations of calibration sources that relied on blackbody emission. The emitter is fabricated using a silicon- on-insulator substrate wafer. The buried oxide is chosen to be less than 1 micron thick, and the silicon device thickness is 1-2 microns. Layers of phosphorus compensated with boron are implanted into and diffused throughout the full thickness of the silicon device layer to create the thermometer and heater components. Degenerately doped wiring is implanted to connect the devices to wire-bondable contact pads at the edge of the emitter chip. Then the device is micromachined to remove the thick-handle silicon behind the thermometer and heater components, and to thermally isolate it on a silicon membrane. An impedance- matched emissive coating (ion assisted evaporated Bi) is applied to the back of the membrane to enable high-efficiency emission of the blackbody spectrum.

  6. Low SWaP MWIR detector based on XBn focal plane array

    NASA Astrophysics Data System (ADS)

    Klipstein, P. C.; Gross, Y.; Aronov, D.; ben Ezra, M.; Berkowicz, E.; Cohen, Y.; Fraenkel, R.; Glozman, A.; Grossman, S.; Klin, O.; Lukomsky, I.; Marlowitz, T.; Shkedy, L.; Shtrichman, I.; Snapi, N.; Tuito, A.; Yassen, M.; Weiss, E.

    2013-06-01

    Over the past few years, a new type of High Operating Temperature (HOT) photon detector has been developed at SCD, which operates in the blue part of the MWIR window of the atmosphere (3.4-4.2 μm). This window is generally more transparent than the red part of the MWIR window (4.4-4.9 μm), especially for mid and long range applications. The detector has an InAsSb active layer, and is based on the new "XBn" device concept. We have analyzed various electrooptical systems at different atmospheric temperatures, based on XBn-InAsSb operating at 150K and epi-InSb at 95K, respectively, and find that the typical recognition ranges of both detector technologies are similar. Therefore, for very many applications there is no disadvantage to using XBn-InAsSb instead of InSb. On the other hand XBn technology confers many advantages, particularly in low Size, Weight and Power (SWaP) and in the high reliability of the cooler and Integrated Detector Cooler Assembly (IDCA). In this work we present a new IDCA, designed for 150K operation. The 15 μm pitch 640×512 digital FPA is housed in a robust, light-weight, miniaturised Dewar, attached to Ricor's K562S Stirling cycle cooler. The complete IDCA has a diameter of 28 mm, length of 80 mm and weight of < 300 gm. The total IDCA power consumption is ~ 3W at a 60Hz frame rate, including an external miniature proximity card attached to the outside of the Dewar. We describe some of the key performance parameters of the new detector, including its NETD, RNU and operability, pixel cross-talk, and early stage yield results from our production line.

  7. Improved charge injection device and a focal plane interface electronics board for stellar tracking

    NASA Technical Reports Server (NTRS)

    Michon, G. J.; Burke, H. K.

    1984-01-01

    An improved Charge Injection Device (CID) stellar tracking sensor and an operating sensor in a control/readout electronics board were developed. The sensor consists of a shift register scanned, 256x256 CID array organized for readout of 4x4 subarrays. The 4x4 subarrays can be positioned anywhere within the 256x256 array with a 2 pixel resolution. This allows continuous tracking of a number of stars simultaneously since nine pixels (3x3) centered on any star can always be read out. Organization and operation of this sensor and the improvements in design and semiconductor processing are described. A hermetic package incorporating an internal thermoelectric cooler assembled using low temperature solders was developed. The electronics board, which contains the sensor drivers, amplifiers, sample hold circuits, multiplexer, analog to digital converter, and the sensor temperature control circuits, is also described. Packaged sensors were evaluated for readout efficiency, spectral quantum efficiency, temporal noise, fixed pattern noise, and dark current. Eight sensors along with two tracker electronics boards were completed, evaluated, and delivered.

  8. Hydrocarbon provinces and productive trends in Libya and adjacent areas

    SciTech Connect

    Missallati, A.A. Ltd., Tripoli )

    1988-08-01

    According to the age of major reservoirs, hydrocarbon occurrences in Libya and adjacent areas can be grouped into six major systems which, according to their geographic locations, can be classified into two major hydrocarbon provinces: (1) Sirte-Pelagian basins province, with major reservoirs ranging from middle-late Mesozoic to early Tertiary, and (2) Murzog-Ghadames basins province, with major reservoirs ranging from early Paleozoic to early Mesozoic. In the Sirte-Pelagian basins province, hydrocarbons have been trapped in structural highs or in stratigraphic wedge-out against structural highs and in carbonate buildups. Here, hydrocarbon generation is characterized by the combined effect of abundant structural relief and reservoir development in the same hydrocarbon systems of the same age, providing an excellent example of hydrocarbon traps in sedimentary basins that have undergone extensive tensional fracturing in a shallow marine environment. In the Murzog-Ghadames basins province, hydrocarbons have been trapped mainly in structural highs controlled by paleostructural trends as basement arches which acted as focal points for oil migration and accumulation.

  9. NASA Connect: 'Plane Weather'

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Excerpt from the NASA Connect show 'Plane Weather' This clip explains what high and low pressure weather systems are, and how they form. Weather affects our daily lives. The elements of weather: rain, wind, fog, ice and snow affect the operation and flight of an airplane. In this program, NASA and FAA researchers will introduce students to math, science, and weather; demonstrate how these elements influence flight; and show how NASA and FAA research is used to limit the effects of these elements on flight. Students will examine: the tools, techniques, and technologies used by engineers and scientists to detect these and other climatological factors affecting aircraft in flight. The lesson and classroom experiment will involve students in the scientific process and emphasizing problem solving, measurement, and reasoning skills.

  10. NASA Connect: 'Plane Weather'

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Excerpt from the NASA Connect show 'Plane Weather' This clip explains what high and low pressure weather systems are, and how these affect weather patterns. Weather affects our daily lives. The elements of weather: rain, wind, fog, ice and snow affect the operation and flight of an airplane. In this program, NASA and FAA researchers will introduce students to math, science, and weather; demonstrate how these elements influence flight; and show how NASA and FAA research is used to limit the effects of these elements on flight. Students will examine: the tools, techniques, and technologies used by engineers and scientists to detect these and other climatological factors affecting aircraft in flight. The lesson and classroom experiment will involve students in the scientific process and emphasizing problem solving, measurement, and reasoning skills.

  11. Finding the Focal Axes of Offset Antennas

    NASA Technical Reports Server (NTRS)

    Schmidt, R. F.

    1982-01-01

    Focal axis of offset paraboloidal reflector antennas determined by direct measurement instead of trial and error. Two feed horns transmit sum or difference pattern to antenna under test, which reflects energy to far-field detector. When axis of feed horns coincides with focal axis of antenna reflector, far-field detector records minimum in amplitude difference and maximum in absolute-magnitude phase difference between sum and difference signals.

  12. Fault parameter constraints using relocated earthquakes: A validation of first-motion focal-mechanism data

    USGS Publications Warehouse

    Kilb, Debi; Hardebeck, J.L.

    2006-01-01

    We estimate the strike and dip of three California fault segments (Calaveras, Sargent, and a portion of the San Andreas near San Jaun Bautistia) based on principle component analysis of accurately located microearthquakes. We compare these fault orientations with two different first-motion focal mechanism catalogs: the Northern California Earthquake Data Center (NCEDC) catalog, calculated using the FPFIT algorithm (Reasenberg and Oppenheimer, 1985), and a catalog created using the HASH algorithm that tests mechanism stability relative to seismic velocity model variations and earthquake location (Hardebeck and Shearer, 2002). We assume any disagreement (misfit >30° in strike, dip, or rake) indicates inaccurate focal mechanisms in the catalogs. With this assumption, we can quantify the parameters that identify the most optimally constrained focal mechanisms. For the NCEDC/FPFIT catalogs, we find that the best quantitative discriminator of quality focal mechanisms is the station distribution ratio (STDR) parameter, an indicator of how the stations are distributed about the focal sphere. Requiring STDR > 0.65 increases the acceptable mechanisms from 34%–37% to 63%–68%. This suggests stations should be uniformly distributed surrounding, rather than aligning, known fault traces. For the HASH catalogs, the fault plane uncertainty (FPU) parameter is the best discriminator, increasing the percent of acceptable mechanisms from 63%–78% to 81%–83% when FPU ≤ 35°. The overall higher percentage of acceptable mechanisms and the usefulness of the formal uncertainty in identifying quality mechanisms validate the HASH approach of testing for mechanism stability.

  13. Acoustic Emission, b-values and Foliation Plane Anisotropy

    NASA Astrophysics Data System (ADS)

    Sehizadeh, Mahdi; Nasseri, Mohammad H.; Ye, Sheng; Young, R. Paul

    2016-04-01

    The b-value and D-value are two parameters related to size and distance distribution of earthquakes. There are many different factors affecting b-value such as stress state, thermal gradients, focal mechanism and heterogeneity. For example, the literature shows that the b-value changes systematically with respect to the focal mechanism. In laboratory experiments, foliation planes introduce a weakness in samples and can be considered as a potential for rupture or pre-existing faults, so they may exhibit similar relationships. The D-value defines the degree of clustering of earthquakes and would be expected to have a defined relationship with respect to the anisotropy. Using a unique facility in the Rock Fracture Dynamics laboratory at the University of Toronto, three sets of polyaxial experiments have been performed on cubic samples with foliation planes systematically oriented at different angles to the principal stress direction. During these tests, samples were loaded under controlled true-triaxial stress conditions until they failed or had severe damage and acoustic emission events were recorded using 18 sensors around the samples. The paper describes how the combination of stress state and foliation planes affects the b-value and D-value under laboratory conditions.

  14. Sighting optics including an optical element having a first focal length and a second focal length

    DOEpatents

    Crandall, David Lynn

    2011-08-01

    One embodiment of sighting optics according to the teachings provided herein may include a front sight and a rear sight positioned in spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus, for a user, images of the front sight and the target.

  15. Resolution in 3D in multifocal plane microscopy

    NASA Astrophysics Data System (ADS)

    Chao, Jerry; Ram, Sripad; Abraham, Anish V.; Ward, E. Sally; Ober, Raimund J.

    2008-02-01

    Using single molecule microscopy, biological interactions can be imaged and studied at the level of individual biomolecules. When characterizing an imaged biological interaction, the distance separating the two participating biomolecules can provide valuable information. Therefore, the resolvability of an imaging setup is of practical significance in the analysis of the acquired image data. Importantly, the resolvability of the imaging setup needs evaluation in the 3D context, since in general biomolecules reside in 3D space within the cellular environment. We recently introduced an information-theoretic 2D resolution measure which shows that the resolution limit due to Rayleigh's criterion can be overcome. This new result predicts that the resolution of optical microscopes is not limited, but rather can be improved with increased photon counts detected from the single molecules. The 2D result was subsequently extended to the 3D context, and the proposed information-theoretic 3D resolution measure can readily be used to determine the resolvability of a conventional single focal plane imaging setup. Here, we consider the 3D resolution measure for a multifocal plane microscope setup, an imaging system which allows the concurrent imaging of multiple focal planes within a specimen. The technique is useful in applications such as the tracking of subcellular objects in 3D. By comparing their 3D resolution measures, we find a two-plane setup to outperform a comparable conventional single-plane setup in resolvability over a range of axial locations for the single molecule pair. Moreover, we investigate and compare the impact of noise on the resolvability of the two setups.

  16. Transparent Meta-Analysis: Does Aging Spare Prospective Memory with Focal vs. Non-Focal Cues?

    PubMed Central

    Uttl, Bob

    2011-01-01

    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. PMID:21304905

  17. Focal Adhesion-Independent Cell Migration.

    PubMed

    Paluch, Ewa K; Aspalter, Irene M; Sixt, Michael

    2016-10-06

    Cell migration is central to a multitude of physiological processes, including embryonic development, immune surveillance, and wound healing, and deregulated migration is key to cancer dissemination. Decades of investigations have uncovered many of the molecular and physical mechanisms underlying cell migration. Together with protrusion extension and cell body retraction, adhesion to the substrate via specific focal adhesion points has long been considered an essential step in cell migration. Although this is true for cells moving on two-dimensional substrates, recent studies have demonstrated that focal adhesions are not required for cells moving in three dimensions, in which confinement is sufficient to maintain a cell in contact with its substrate. Here, we review the investigations that have led to challenging the requirement of specific adhesions for migration, discuss the physical mechanisms proposed for cell body translocation during focal adhesion-independent migration, and highlight the remaining open questions for the future.

  18. Measuring microfocus focal spots using digital radiography

    SciTech Connect

    Fry, David A

    2009-01-01

    Measurement of microfocus spot size can be important for several reasons: (1) Quality assurance during manufacture of microfocus tubes; (2) Tracking performance and stability of microfocus tubes; (3) Determining magnification (especially important for digital radiography where the native spatial resolution of the digital system is not adequate for the application); (4) Knowledge of unsharpness from the focal spot alone. The European Standard EN 12543-5 is based on a simple geometrical method of calculating focal spot size from unsharpness of high magnification film radiographs. When determining microfocus focal spot dimensions using unsharpness measurements both signal-to-noise (SNR) and magnification can be important. There is a maximum accuracy that is a function of SNR and therefore an optimal magnification. Greater than optimal magnification can be used but it will not increase accuracy.

  19. 3D fluorescence anisotropy imaging using selective plane illumination microscopy

    PubMed Central

    Hedde, Per Niklas; Ranjit, Suman; Gratton, Enrico

    2015-01-01

    Fluorescence anisotropy imaging is a popular method to visualize changes in organization and conformation of biomolecules within cells and tissues. In such an experiment, depolarization effects resulting from differences in orientation, proximity and rotational mobility of fluorescently labeled molecules are probed with high spatial resolution. Fluorescence anisotropy is typically imaged using laser scanning and epifluorescence-based approaches. Unfortunately, those techniques are limited in either axial resolution, image acquisition speed, or by photobleaching. In the last decade, however, selective plane illumination microscopy has emerged as the preferred choice for three-dimensional time lapse imaging combining axial sectioning capability with fast, camera-based image acquisition, and minimal light exposure. We demonstrate how selective plane illumination microscopy can be utilized for three-dimensional fluorescence anisotropy imaging of live cells. We further examined the formation of focal adhesions by three-dimensional time lapse anisotropy imaging of CHO-K1 cells expressing an EGFP-paxillin fusion protein. PMID:26368202

  20. Extensive Focal Epithelial Hyperplasia: A Case Report.

    PubMed

    Mansouri, Zahra; Bakhtiari, Sedigheh; Noormohamadi, Robab

    2015-01-01

    Focal epithelial hyperplasia (FEH) or Heck's disease is a rare viral infection of the oral mucosa caused by human papilloma virus especially subtypes 13 or 32. The frequency of this disease varies widely from one geographic region and ethnic groups to another. This paper reports an Iranian case of extensive focal epithelial hyperplasia. A 35-year-old man with FEH is described, in whom the lesions had persisted for more than 25 years. The lesion was diagnosed according to both clinical and histopathological features. Dental practitioner should be aware of these types of lesions and histopathological examination together and a careful clinical observation should be carried out for a definitive diagnosis.

  1. A simple method for focal length measurement

    NASA Astrophysics Data System (ADS)

    Ma, Hua; Ren, Huan; Zhang, Lin; Shi, Zhengdong; Yuan, Quan; Yang, Yi

    2016-09-01

    A simple method for focal length measurement based on image processing is demonstrated and discussed. The collimated beam, detector, motorized translation stage and computer make up of this test system. The two spots pass through the tested lens is accepted by detector, which is transferred twice by motorized translation stage. By acquired the difference of two spots by image processing, the focal length of the tested lens can be gained. The error sources in the measurement are analyzed. Then the results of experiment show that the relative error was 0.1%. This method can be used in workshop and labs for its convenience and low cost.

  2. Natural course of symptomatic focal choroidal excavation.

    PubMed

    Pierro, Luisa; Casalino, Giuseppe; Introini, Ugo; Gagliardi, Marco; Sergenti, Jessica; Cascavilla, Maria Lucia; Bandello, Francesco

    2015-01-01

    A 32-year-old man was referred to the authors' department for nonspecified macular dystrophy with persistent metamorphopsia in the right eye diagnosed 10 years before and followed using optical coherence tomography. The patient underwent a comprehensive ocular examination, including multimodal imaging evaluation and electrofunctional testing. The diagnosis was consistent with nonconforming focal choroid excavation. Over 10 years, no complications occurred, visual acuity was stable, and optical coherence tomography showed no progression of the lesion during follow-up. In this case, nonconforming symptomatic focal choroid excavation was a nonprogressive condition with good long-term visual outcome.

  3. [Liver ultrasound: focal lesions and diffuse diseases].

    PubMed

    Segura Grau, A; Valero López, I; Díaz Rodríguez, N; Segura Cabral, J M

    2016-01-01

    Liver ultrasound is frequently used as a first-line technique for the detection and characterization of the most common liver lesions, especially those incidentally found focal liver lesions, and for monitoring of chronic liver diseases. Ultrasound is not only used in the Bmode, but also with Doppler and, more recently, contrast-enhanced ultrasound. It is mainly used in the diagnosis of diffuse liver diseases, such as steatosis or cirrhosis. This article presents a practical approach for diagnosis workup, in which the different characteristics of the main focal liver lesions and diffuse liver diseases are reviewed.

  4. Crystal diffraction lens with variable focal length

    DOEpatents

    Smither, R.K.

    1991-04-02

    A method and apparatus for altering the focal length of a focusing element of one of a plurality of pre-determined focal lengths by changing heat transfer within selected portions of the element by controlled quantities is disclosed. Control over heat transfer is accomplished by manipulating one or more of a number of variables, including: the amount of heat or cold applied to surfaces; type of fluids pumped through channels for heating and cooling; temperatures, directions of flow and rates of flow of fluids; and placement of channels. 19 figures.

  5. Crystal diffraction lens with variable focal length

    DOEpatents

    Smither, Robert K.

    1991-01-01

    A method and apparatus for altering the focal length of a focusing element o one of a plurality of pre-determined focal lengths by changing heat transfer within selected portions of the element by controlled quantities. Control over heat transfer is accomplished by manipulating one or more of a number of variables, including: the amount of heat or cold applied to surfaces; type of fluids pumped through channels for heating and cooling; temperatures, directions of flow and rates of flow of fluids; and placement of channels.

  6. Actinic Granuloma with Focal Segmental Glomerulosclerosis

    PubMed Central

    Phasukthaworn, Ruedee; Chanprapaph, Kumutnart; Vachiramon, Vasanop

    2016-01-01

    Actinic granuloma is an uncommon granulomatous disease, characterized by annular erythematous plaque with central clearing predominately located on sun-damaged skin. The pathogenesis is not well understood, ultraviolet radiation is recognized as precipitating factor. We report a case of a 52-year-old woman who presented with asymptomatic annular erythematous plaques on the forehead and both cheeks persisting for 2 years. The clinical presentation and histopathologic findings support the diagnosis of actinic granuloma. During that period of time, she also developed focal segmental glomerulosclerosis. The association between actinic granuloma and focal segmental glomerulosclerosis needs to be clarified by further studies. PMID:27293392

  7. [Antiperspirants for the therapy of focal hyperhidrosis].

    PubMed

    Streker, M; Kerscher, M

    2012-06-01

    In Europe often no clear distinction is made between deodorant and antiperspirant. Particularly in Germany, the labeling "deo" is used for both. Only antiperspirants are capable of influencing the activity of eccrine sweat glands. In the treatment of focal hyperhidrosis, the use of aluminum chloride solutions represents the first choice. The efficacy is well documented in a variety of studies. Subjective side effects include pruritus and - less often - irritant dermatitis, which can be treated symptomatically and usually does not require discontinuation of the treatment. Rare variants of focal hyperhidrosis like auriculotemporal syndrome, Ross syndrome and nevus sudoriferus also are suitable for treatment with topical aluminum chloride hexahydrate solutions.

  8. Adjacent Segment Pathology after Anterior Cervical Fusion

    PubMed Central

    Chung, Jae Yoon; Park, Jong-Beom; Seo, Hyoung-Yeon

    2016-01-01

    Anterior cervical fusion has become a standard of care for numerous pathologic conditions of the cervical spine. However, subsequent development of clinically significant disc disease at levels adjacent to fused discs is a serious long-term complication of this procedure. As more patients live longer after surgery, it is foreseeable that adjacent segment pathology (ASP) will develop in increasing numbers of patients. Also, ASP has been studied more intensively with the recent popularity of motion preservation technologies like total disc arthroplasty. The true nature and scope of ASP remains poorly understood. The etiology of ASP is most likely multifactorial. Various factors including altered biomechanical stresses, surgical disruption of soft tissue and the natural history of cervical disc disease contribute to the development of ASP. General factors associated with disc degeneration including gender, age, smoking and sports may play a role in the development of ASP. Postoperative sagittal alignment and type of surgery are also considered potential causes of ASP. Therefore, a spine surgeon must be particularly careful to avoid unnecessary disruption of the musculoligamentous structures, reduced risk of direct injury to the disc during dissection and maintain a safe margin between the plate edge and adjacent vertebrae during anterior cervical fusion. PMID:27340541

  9. A modified method for determining the focal ratio degradation and length properties of optical fibres in astronomy

    NASA Astrophysics Data System (ADS)

    Yan, Yunxiang; Wang, Gang; Sun, Weimin; Luo, A.-Li; Ma, Zhenyu; Li, Jian; Wang, Shuqing

    2017-04-01

    Focal ratio degradation (FRD) is a major contributor to throughput and light loss in a fibre spectroscopic telescope system. We combine the guided mode theory in geometric optics and a well-known model, the power distribution model (PDM), to predict and explain the FRD dependence properties. We present a robust method by modifying the energy distribution method with f-intercept to control the input condition. This method provides a way to determine the proper position of the fibre end on the focal plane to improve energy utilization and FRD performance, which lifts the relative throughput up to 95 per cent with variation of output focal ratio less than 2 per cent. This method can also help to optimize the arrangement of the position of focal-plane plate to enhance the coupling efficiency in a telescope. To investigate length properties, we modified the PDM by introducing a new parameter, the focal distance f, into the original model to make it available for a multiposition measurement system. The results show that the modified model is robust and feasible for measuring the key parameter d0 to simulate the transmission characteristics. The output focal ratio in the experiment does not follow the prediction trend but shows an interesting phenomenon: the output focal ratio increases first to the peak, then decreases and remains stable finally with increasing fibre length longer than 15 m. This provides a reference for choosing the appropriate length of fibre to improve the FRD performance for the design of the fibre system in a telescope.

  10. FMC: a one-liner Python program to manage, classify and plot focal mechanisms

    NASA Astrophysics Data System (ADS)

    Álvarez-Gómez, José A.

    2014-05-01

    The analysis of earthquake focal mechanisms (or Seismic Moment Tensor, SMT) is a key tool on seismotectonics research. Each focal mechanism is characterized by several location parameters of the earthquake hypocenter, the earthquake size (magnitude and scalar moment tensor) and some geometrical characteristics of the rupture (nodal planes orientations, SMT components and/or SMT main axes orientations). The aim of FMC is to provide a simple but powerful tool to manage focal mechanism data. The data should be input to the program formatted as one of two of the focal mechanisms formatting options of the GMT (Generic Mapping Tools) package (Wessel and Smith, 1998): the Harvard CMT convention and the single nodal plane Aki and Richards (1980) convention. The former is a SMT format that can be downloaded directly from the Global CMT site (http://www.globalcmt.org/), while the later is the simplest way to describe earthquake rupture data. FMC is programmed in Python language, which is distributed as Open Source GPL-compatible, and therefore can be used to develop Free Software. Python runs on almost any machine, and has a wide support and presence in any operative system. The program has been conceived with the modularity and versatility of the classical UNIX-like tools. Is called from the command line and can be easily integrated into shell scripts (*NIX systems) or batch files (DOS/Windows systems). The program input and outputs can be done by means of ASCII files or using standard input (or redirection "<"), standard output (screen or redirection ">") and pipes ("|"). By default FMC will read the input and write the output as a Harvard CMT (psmeca formatted) ASCII file, although other formats can be used. Optionally FMC will produce a classification diagram representing the rupture type of the focal mechanisms processed. In order to count with a detailed classification of the focal mechanisms I decided to classify the focal mechanism in a series of fields that include

  11. Sensory-motor integration in focal dystonia.

    PubMed

    Avanzino, Laura; Tinazzi, Michele; Ionta, Silvio; Fiorio, Mirta

    2015-12-01

    Traditional definitions of focal dystonia point to its motor component, mainly affecting planning and execution of voluntary movements. However, focal dystonia is tightly linked also to sensory dysfunction. Accurate motor control requires an optimal processing of afferent inputs from different sensory systems, in particular visual and somatosensory (e.g., touch and proprioception). Several experimental studies indicate that sensory-motor integration - the process through which sensory information is used to plan, execute, and monitor movements - is impaired in focal dystonia. The neural degenerations associated with these alterations affect not only the basal ganglia-thalamic-frontal cortex loop, but also the parietal cortex and cerebellum. The present review outlines the experimental studies describing impaired sensory-motor integration in focal dystonia, establishes their relationship with changes in specific neural mechanisms, and provides new insight towards the implementation of novel intervention protocols. Based on the reviewed state-of-the-art evidence, the theoretical framework summarized in the present article will not only result in a better understanding of the pathophysiology of dystonia, but it will also lead to the development of new rehabilitation strategies.

  12. [Focal epithelial hyperplasia. An unusual clinical aspect].

    PubMed

    Bodokh, I; Lacour, J P; Rainero, C; Orth, G; Perrin, C; Hoffman, P; Santini, J; Ortonne, J P

    1993-01-01

    We report a case of focal epithelial hyperplasia in a child born in France of Algerian parents. The clinical appearance was unusual in that certain lesions were verrucous and pediculate. A virological study revealed the presence of papillomavirus 32, one of the two types of HPV specifically associated with this entity.

  13. Pure Gerstmann's syndrome from a focal lesion.

    PubMed

    Roeltgen, D P; Sevush, S; Heilman, K M

    1983-01-01

    It is controversial whether a focal lesion can specifically induce Gerstmann's syndrome (dyscalculia, left-right disorientation, finger agnosia, and agraphia). Also, Gerstmann's tetrad has been attributed to other cerebral symptoms, particularly aphasia. We examined a patient who had all four symptoms of Gerstmann's syndrome, without other symptoms or signs, and who had a discrete left parietal lesion.

  14. Complex source description of focal regions.

    PubMed

    Monzon, Cesar; Forester, Donald W; Moore, Peter

    2006-04-01

    Closed-form solutions of the two-dimensional homogeneous wave equation are presented that provide focal-region descriptions corresponding to a converging bundle of rays. The solutions do have evanescent wave content and can be described as a source-sink pair or particle-antiparticle pair, collocated in complex space, with the complex location being critical in the determination of beam shape and focal region size. The wave solutions are not plagued by singularities, have a finite energy, and have a limitation on how small the focal size can get, with a penalty for limiting small spot sizes in the form of impractically high associated reactive energy. The electric-field-defined spot-size limiting value is 0.35lambda x 0.35lambda, which is about 38% of the Poynting-vector-defined minimum spot size (0.8lambda x 0.4lambda) and corresponds to a condition related to the maximum possible beam angle. A multiple set of solutions is introduced, and the elementary solutions are used to produce new solutions via superposition, resulting in fields with chiral character or with increased depth of focus. We do not claim generality, as the size of focal regions exhibited by the closed-form solutions has a lower bound and hence is not able to account for Pendry's "ideal lens" scenario.

  15. Estimation of focal and extra-focal radiation profiles based on Gaussian modeling in medical linear accelerators.

    PubMed

    Anai, Shigeo; Arimura, Hidetaka; Nakamura, Katsumasa; Araki, Fujio; Matsuki, Takaomi; Yoshikawa, Hideki; Yoshidome, Satoshi; Shioyama, Yoshiyuki; Honda, Hiroshi; Ikeda, Nobuo

    2011-07-01

    The X-ray source or focal radiation is one of the factors that can degrade the conformal field edge in stereotactic body radiotherapy. For that reason, it is very important to estimate the total focal radiation profiles of linear accelerators, which consists of X-ray focal-spot radiation and extra-focal radiation profiles. Our purpose in this study was to propose an experimental method for estimating the focal-spot and extra-focal radiation profiles of linear accelerators based on triple Gaussian functions. We measured the total X-ray focal radiation profiles of the accelerators by moving a slit in conjunction with a photon field p-type silicon diode. The slit width was changed so that the extra-focal radiation could be optimally included in the total focal radiation. The total focal radiation profiles of an accelerator at 4-MV and 10-MV energies were approximated with a combination of triple Gaussian functions, which correspond to the focal-spot radiation, extra-focal radiation, and radiation transmitted through the slit assembly. As a result, the ratios of the Gaussian peak value of the extra-focal radiation to that of the focal spot for 4 and 10 MV were 0.077 and 0.159, respectively. The peak widths of the focal-spot and extra-focal radiation profiles were 0.57 and 25.0 mm for 4 MV, respectively, and 0.60 and 22.0 mm for 10 MV, respectively. We concluded that the proposed focal radiation profile model based on the triple Gaussian functions may be feasible for estimating the X-ray focal-spot and extra-focal radiation profiles.

  16. Testing wetland axioms at a watershed scale: Case studies of the aggregate hydrologic effects of non-adjacent wetlands

    NASA Astrophysics Data System (ADS)

    Evenson, G.; Golden, H. E.; Lane, C.; D'Amico, E.

    2015-12-01

    Wetlands not adjacent to streams (i.e. "non-adjacent wetlands") are hypothesized to affect downgradient hydrology in a number of ways. Non-adjacent wetlands may, for example, attenuate peak flows, serve as focal points for groundwater recharge, and decrease streamflow variability. The lack of spatially and temporally continuous data elucidating these relationships makes hydrological models an important medium for testing these hypotheses at broad spatial scales (e.g., mesoscale watersheds). We present results from two case studies that apply a hydrological model modified to represent non-adjacent wetland hydrological processes and thereby evaluate their watershed-scale aggregate hydrological effects. We focus on non-adjacent wetlands in two North American landscapes: (1) a ~202 km2 watershed in the Coastal Plain with an extensive distribution of Carolina Bay wetlands and (2) a ~1672 km2 watershed in the Great Plains, which is characterized by a dense distribution of landscape depressions (i.e., prairie potholes). Preliminary results suggest that non-adjacent wetlands significantly affect downgradient hydrology in both landscapes - specifically the baseflow and quickflow components of the hydrograph. However, the emergent watershed-scale hydrological effects of non-adjacent wetlands in the two diverse landscapes differ widely, primarily in response to the varying importance of wetland (e.g., discharge, recharge, flow-through) and wetland to stream transport (e.g., surface, shallow subsurface, deep groundwater flows) functions in these systems. We highlight the watershed-scale hydrological effects of non-adjacent wetlands in these two physiographic settings and describe the need for additional analyses of wetlands in disparate landscapes, using alternative conceptual and simulation models.

  17. Spontaneous gesture and spatial language: Evidence from focal brain injury

    PubMed Central

    Göksun, Tilbe; Lehet, Matthew; Malykhina, Katsiaryna; Chatterjee, Anjan

    2015-01-01

    People often use spontaneous gestures when communicating spatial information. We investigated focal brain-injured individuals to test the hypotheses that (1) naming motion event components of manner-path (represented by verbs-prepositions in English) are impaired selectively, (2) gestures compensate for impaired naming. Patients with left or right hemisphere damage (LHD or RHD) and elderly control participants were asked to describe motion events (e.g., running across) depicted in brief videos. Damage to the left posterior middle frontal gyrus, left inferior frontal gyrus, and left anterior superior temporal gyrus (aSTG) produced impairments in naming paths of motion; lesions to the left caudate and adjacent white matter produced impairments in naming manners of motion. While the frequency of spontaneous gestures were low, lesions to the left aSTG significantly correlated with greater production of path gestures. These suggest that producing prepositions-verbs can be separately impaired and gesture production compensates for naming impairments when damage involves left aSTG. PMID:26283001

  18. Irreversible Electroporation for Focal Ablation at the Porta Hepatis

    SciTech Connect

    Kasivisvanathan, Veeru; Thapar, Ankur Oskrochi, Youssof; Picard, John; Leen, Edward L. S.

    2012-12-15

    Patients with chemotherapy-refractory liver metastases who are not candidates for surgery may be treated with focal ablation techniques with established survival benefits. Irreversible electroporation is the newest of these and has the putative advantages of a nonthermal action, preventing damage to adjacent biliary structures and bowel. This report describes the use of irreversible electroporation in a 61-year-old man with a solitary chemoresistant liver metastasis unsuitable for radiofrequency ablation as a result of its proximity to the porta hepatis. At 3 months, tumor size was decreased on computed tomography from 28 Multiplication-Sign 19 to 20 Multiplication-Sign 17 mm, representing stable disease according to the response evaluation criteria in solid tumors. This corresponded to a decrease in tumor volume size from 5.25 to 3.16 cm{sup 3}. There were no early or late complications. Chemoresistant liver metastases in the proximity of the porta hepatis that are considered to be too high a risk for conventional surgery or thermal ablation may be considered for treatment by the novel ablation technique of irreversible electroporation.

  19. Light scattering by adjacent red blood cells: a mathematical model

    NASA Astrophysics Data System (ADS)

    Uzunoglou, Nikolaos K.; Stamatakos, Georgios; Koutsouris, Dimitrios; Yova-Loukas, Dido M.

    1995-01-01

    Simple approximate scattering theories such as the Rayleigh-Gans theory are not generally applicable to the case of light scattering by red blood cell (RBC) aggregates, including thrombus. This is mainly due to the extremely short distance separating erythrocytes in the aggregates (of the order of 25 nm) as well as to the substantial size of the aggregates. Therefore, in this paper a new mathematical model predicting the electromagnetic field produced by the scattering of a plane electromagnetic wave by a system of two adjacent RBCs is presented. Each RBC is modeled as a homogeneous dielectric ellipsoid of complex index of refraction surrounded by transparent plasma. The relative position and orientation of the ellipsoids are arbitrary. Scattering is formulated in terms of an integral equation which, however, contains two singular kernels. The singular equation is transformed into a pair of nonsingular integral equations for the Fourier transform of the internal field of each RBC. The latter equations are solved by reducing them by quadrature into a matrix equation. The resulting solutions are used to estimate the scattering amplitude. Convergence aspects concerning the numerical calculation of the matrix elements originating from the interaction between the RBCs are also presented.

  20. Adjacent-level arthroplasty following cervical fusion.

    PubMed

    Rajakumar, Deshpande V; Hari, Akshay; Krishna, Murali; Konar, Subhas; Sharma, Ankit

    2017-02-01

    OBJECTIVE Adjacent-level disc degeneration following cervical fusion has been well reported. This condition poses a major treatment dilemma when it becomes symptomatic. The potential application of cervical arthroplasty to preserve motion in the affected segment is not well documented, with few studies in the literature. The authors present their initial experience of analyzing clinical and radiological results in such patients who were treated with arthroplasty for new or persistent arm and/or neck symptoms related to neural compression due to adjacent-segment disease after anterior cervical discectomy and fusion (ACDF). METHODS During a 5-year period, 11 patients who had undergone ACDF anterior cervical discectomy and fusion (ACDF) and subsequently developed recurrent neck or arm pain related to adjacent-level cervical disc disease were treated with cervical arthroplasty at the authors' institution. A total of 15 devices were implanted (range of treated levels per patient: 1-3). Clinical evaluation was performed both before and after surgery, using a visual analog scale (VAS) for pain and the Neck Disability Index (NDI). Radiological outcomes were analyzed using pre- and postoperative flexion/extension lateral radiographs measuring Cobb angle (overall C2-7 sagittal alignment), functional spinal unit (FSU) angle, and range of motion (ROM). RESULTS There were no major perioperative complications or device-related failures. Statistically significant results, obtained in all cases, were reflected by an improvement in VAS scores for neck/arm pain and NDI scores for neck pain. Radiologically, statistically significant increases in the overall lordosis (as measured by Cobb angle) and ROM at the treated disc level were observed. Three patients were lost to follow-up within the first year after arthroplasty. In the remaining 8 cases, the duration of follow-up ranged from 1 to 3 years. None of these 8 patients required surgery for the same vertebral level during the follow