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Sample records for 130nm hybrid pixel

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

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

    NASA Astrophysics Data System (ADS)

    Wermes, N.

    2015-12-01

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

  3. The TDCpix readout ASIC: A 75 ps resolution timing front-end for the NA62 Gigatracker hybrid pixel detector

    NASA Astrophysics Data System (ADS)

    Kluge, A.; Aglieri Rinella, G.; Bonacini, S.; Jarron, P.; Kaplon, J.; Morel, M.; Noy, M.; Perktold, L.; Poltorak, K.

    2013-12-01

    The TDCpix is a novel pixel readout ASIC for the NA62 Gigatracker detector. NA62 is a new experiment being installed at the CERN Super Proton Synchrotron. Its Gigatracker detector shall provide on-beam tracking and time stamping of individual particles with a time resolution of 150 ps rms. It will consist of three tracking stations, each with one hybrid pixel sensor. The peak flow of particles crossing the detector modules reaches 1.27 MHz/mm2 for a total rate of about 0.75 GHz. Ten TDCpix chips will be bump-bonded to every silicon pixel sensor. Each chip shall perform time stamping of 100 M particle hits per second with a detection efficiency above 99% and a timing accuracy better than 200 ps rms for an overall three-station-setup time resolution of better than 150 ps. The TDCpix chip has been designed in a 130 nm CMOS technology. It will feature 45×40 square pixels of 300×300 μm2 and a complex End of Column peripheral region including an array of TDCs based on DLLs, four high speed serializers, a low-jitter PLL, readout and control circuits. This contribution will describe the complete design of the final TDCpix ASIC. It will discuss design choices, the challenges faced and some of the lessons learned. Furthermore, experimental results from the testing of circuit prototypes will be presented. These demonstrate the achievement of key performance figures such as a time resolution of the processing chain of 75 ps rms with a laser sent to the center of the pixel and the capability of time stamping charged particles with an overall resolution below 200 ps rms.

  4. Integrated High Resolution Digital Color Light Sensor in 130 nm CMOS Technology

    PubMed Central

    Strle, Drago; Nahtigal, Uroš; Batistell, Graciele; Zhang, Vincent Chi; Ofner, Erwin; Fant, Andrea; Sturm, Johannes

    2015-01-01

    This article presents a color light detection system integrated in 130 nm CMOS technology. The sensors and corresponding electronics detect light in a CIE XYZ color luminosity space using on-chip integrated sensors without any additional process steps, high-resolution analog-to-digital converter, and dedicated DSP algorithm. The sensor consists of a set of laterally arranged integrated photodiodes that are partly covered by metal, where color separation between the photodiodes is achieved by lateral carrier diffusion together with wavelength-dependent absorption. A high resolution, hybrid, ∑∆ ADC converts each photo diode’s current into a 22-bit digital result, canceling the dark current of the photo diodes. The digital results are further processed by the DSP, which calculates normalized XYZ or RGB color and intensity parameters using linear transformations of the three photo diode responses by multiplication of the data with a transformation matrix, where the coefficients are extracted by training in combination with a pseudo-inverse operation and the least-mean square approximation. The sensor system detects the color light parameters with 22-bit accuracy, consumes less than 60 μA on average at 10 readings per second, and occupies approx. 0.8 mm2 of silicon area (including three photodiodes and the analog part of the ADC). The DSP is currently implemented on FPGA. PMID:26205275

  5. Integrated High Resolution Digital Color Light Sensor in 130 nm CMOS Technology.

    PubMed

    Strle, Drago; Nahtigal, Uroš; Batistell, Graciele; Zhang, Vincent Chi; Ofner, Erwin; Fant, Andrea; Sturm, Johannes

    2015-01-01

    This article presents a color light detection system integrated in 130 nm CMOS technology. The sensors and corresponding electronics detect light in a CIE XYZ color luminosity space using on-chip integrated sensors without any additional process steps, high-resolution analog-to-digital converter, and dedicated DSP algorithm. The sensor consists of a set of laterally arranged integrated photodiodes that are partly covered by metal, where color separation between the photodiodes is achieved by lateral carrier diffusion together with wavelength-dependent absorption. A high resolution, hybrid, ∑∆ ADC converts each photo diode's current into a 22-bit digital result, canceling the dark current of the photo diodes. The digital results are further processed by the DSP, which calculates normalized XYZ or RGB color and intensity parameters using linear transformations of the three photo diode responses by multiplication of the data with a transformation matrix, where the coefficients are extracted by training in combination with a pseudo-inverse operation and the least-mean square approximation. The sensor system detects the color light parameters with 22-bit accuracy, consumes less than 60 μA on average at 10 readings per second, and occupies approx. 0.8 mm(2) of silicon area (including three photodiodes and the analog part of the ADC). The DSP is currently implemented on FPGA. PMID:26205275

  6. Capacitively coupled hybrid pixel assemblies for the CLIC vertex detector

    NASA Astrophysics Data System (ADS)

    Tehrani, N. Alipour; Arfaoui, S.; Benoit, M.; Dannheim, D.; Dette, K.; Hynds, D.; Kulis, S.; Perić, I.; Petrič, M.; Redford, S.; Sicking, E.; Valerio, P.

    2016-07-01

    The vertex detector at the proposed CLIC multi-TeV linear e+e- collider must have minimal material content and high spatial resolution, combined with accurate time-stamping to cope with the expected high rate of beam-induced backgrounds. One of the options being considered is the use of active sensors implemented in a commercial high-voltage CMOS process, capacitively coupled to hybrid pixel ASICs. A prototype of such an assembly, using two custom designed chips (CCPDv3 as active sensor glued to a CLICpix readout chip), has been characterised both in the lab and in beam tests at the CERN SPS using 120 GeV/c positively charged hadrons. Results of these characterisation studies are presented both for single and dual amplification stages in the active sensor, where efficiencies of greater than 99% have been achieved at -60 V substrate bias, with a single hit resolution of 6.1 μm . Pixel cross-coupling results are also presented, showing the sensitivity to placement precision and planarity of the glue layer.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  8. Imaging performance of the hybrid pixel detectors XPAD3-S

    NASA Astrophysics Data System (ADS)

    Brunner, F. Cassol; Clemens, J. C.; Hemmer, C.; Morel, C.

    2009-03-01

    Hybrid pixel detectors, originally developed for tracking particles in high-energy physics experiments, have recently been used in material sciences and macromolecular crystallography. Their capability to count single photons and to apply a threshold on the photon energy suggests that they could be optimal digital x-ray detectors in low energy beams such as for small animal computed tomography (CT). To investigate this issue, we have studied the imaging performance of photon counting hybrid pixel detectors based on the XPAD3-S chip. Two detectors are considered, connected either to a Si or to a CdTe sensor, the latter being of interest for its higher efficiency. Both a standard 'International Electrotechnical Commission' (IEC) mammography beam and a beam used for mouse CT results published in the literature are employed. The detector stability, linearity and noise are investigated as a function of the dose for several imaging exposures (~0.1-400 µGy). The perfect linearity of both detectors is confirmed, but an increase in internal noise for counting statistics higher than ~5000 photons has been found, corresponding to exposures above ~110 µGy and ~50 µGy for the Si and CdTe sensors, respectively. The noise power spectrum (NPS), the modulation transfer function (MTF) and the detective quantum efficiency (DQE) are then measured for two energy threshold configurations (5 keV and 18 keV) and three doses (~3, 30 and 300 µGy), in order to obtain a complete estimation of the detector performances. In general, the CdTe sensor shows a clear superiority with a maximal DQE(0) of ~1, thanks to its high efficiency (~100%). The DQE of the Si sensor is more dependent on the radiation quality, due to the energy dependence of its efficiency its maximum is ~0.4 with respect to the softer radiation. Finally, we compare the XPAD3-S DQE with published curves of other digital devices in a similar radiation condition. The XPAD3-S/CdTe detector appears to be the best with the highest

  9. Development of a low power Delay-Locked Loop in two 130 nm CMOS technologies

    NASA Astrophysics Data System (ADS)

    Firlej, M.; Fiutowski, T.; Idzik, M.; Moron, J.; Swientek, K.

    2016-02-01

    The design and measurement results of two low power DLL prototypes for applications in particle physics readout systems are presented. The DLLs were fabricated in two different 130 nm CMOS technologies, called process A and process B, giving the opportunity to compare these two CMOS processes. Both circuits generate 64 uniform clock phases and operate at similar frequency range, from 20 MHz up to 60 MHz (10 MHz - 90 MHz in process B). The period jitter of both DLLs is in the range 2.5 ps - 12.1 ps (RMS) and depends on the selected output phase. The complete DLL functionality was experimentally verified, confirming a very low and frequency scalable power consumption of around 0.7 mW at typical 40 MHz input. The DLL prototype, designed in process A, occupies 680 μm × 210 μm, while the same circuit designed in process B occupies 430 μm × 190 μm.

  10. Characterization of optical proximity matching for 130-nm node gate line width

    NASA Astrophysics Data System (ADS)

    Zheng, Sandra; Zhang, Gary; Wang, ChangAn; Detweiler, Shangting F.

    2003-06-01

    As IC density shrinks based on Moore"s law, optical lithography continually is scaled to print ever-smaller features by using resolution enhancement techniques such as phase shift mask, optical proximity correction (OPC), off-axis illumination and sub-resolution assistant features. OPC has been playing a key role to maximize the overlapping process window through pitch in the sub-wavelength optical lithography. As an important cost control measure, one general OPC model is applied to the full exposure field across multiple scanners. To implement this technique, optical proximity matching of line width across the field and across multiple tools turns out to be very crucial particularly at gate pattern. In addition, it is very important to obtain reliable critical dimension (CD) data sets with low noise level and high accuracy from the metrology tool. Otherwise, extracting the real scanner fingerprint in term of CD can not be achieved with precision in the order of 1nm~2nm. Scatterometry CD measurements have demonstrated excellent results to overcome this problem. The methodology of Scatterometry is emerging as one of the best metrology tool candidates in terms of gate line width control for technology nodes beyond 130nm. This paper investigates the sources of error that consume the CD budget of optical proximity matching for line through pitch (LTP). The study focuses on the 130nm technology node and uses experimental data and Prolith resist vector model based simulations. Scatterometer CD measurements of LTP are used for the first time and effectively correlated to lens aberrations and effective partial coherence (EPC) measurements which were extracted by Litel In-situ Interferometer (ISI) and Source Metrology Instrument (SMI). Implications of optical proximity matching are also discussed for future technology nodes. From the results, the paper also demonstrates the efficacy of scatterometer line through pitch measurements for OPC characterization.

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

    SciTech Connect

    Meng, Ling-Jian

    2014-10-21

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

  12. 130-nm reticle inspection using multibeam UV-wavelength database inspection

    NASA Astrophysics Data System (ADS)

    Aquino, Christopher M.; Schlaffer, Robert

    2002-07-01

    The TeraStar family of reticle inspection systems were introduced in 2000 with die-to-die and STARlightT capability. These tools set the standard for high-resolution reticle inspection for the 130 nm design rule and below. The latest addition to the TeraStar family is the TeraStar SLF77, which extends the tool platform to include die-to-database inspection capability. Sensitivity for Chrome on Glass is 100 nm with much greater tolerance for inspecting aggressive OPC features such as serifs and assist lines. Many advanced reticles that are not inspectable on previous generation inspection tools are all inspectable on the TeraStar SLF77. Data prep times and file structure have been significantly improved with the average prep time being less than 10 percent of the 365UV-HR and average output file size less than 25 percent of the GigaPrep. The TeraStar SLF77 incorporates all the features of the TeraStar family such as triple-beam optics and TeraPro HP High Productivity Modes with the ability to run STARlight inspections concurrently with either die-to-die or die-to-database pattern inspections. Advanced registration algorithms accommodate subtle plate and machine errors to provide high sensitivity with low false detections. Advanced image overlay inspects small lines and OPC features and is very independent of defect shape and location. The TeraStar SLF77 has removed the barriers that existed with previous generation database inspection tools and made advanced reticle die-to-database inspection cost effective. Last October, KLA-Tencor introduced the TeraStar SLF77 and the three beta sites have recently completed beta evaluation. Here we present the first results from the use of the TeraStar in a production environment triple beam die-to-database inspection system. We have also shipped more than ten systems to customers worldwide. This paper describes the implementation of productivity improvements at the beta sites, performance on 130nm node customer product reticles

  13. Recent Developments of HEP Pixel Detector Readout Chips

    NASA Astrophysics Data System (ADS)

    Caminada, Lea

    This article reviews the development of readout integrated circuits for hybrid pixel particle physics detectors. The 250-nm feature size chips in the presently operating ATLAS and CMS experiments are compared with the current state of the art in 130-nm feature size represented by the FE-I4 chip that will be used to add a new beam pipe layer for the ATLAS experiment in 2013 and the upgrade options of the CMS pixel readout chip. This includes a discussion of the array and pixel size, analog performance, readout architecture, power consumption, power distribution options and radiation hardness. Finally, recent work in 65-nm feature size as a means to continue the evolution of readout chip technology towards smaller feature size, higher rate, and lower power is presented.

  14. A history of hybrid pixel detectors, from high energy physics to medical imaging

    NASA Astrophysics Data System (ADS)

    Delpierre, P.

    2014-05-01

    The aim of this paper is to describe the development of hybrid pixel detectors from the origin to the application on medical imaging. We are going to recall the need for fast 2D detectors in the high energy physics experiments and to follow the different pixel electronic circuits created to satisfy this demand. The adaptation of these circuits for X-rays will be presented as well as their industrialization. Today, a number of applications are open for these cameras, particularly for biomedical imaging applications. Some developments for clinical CT will also be shown.

  15. Cryogenic Lifetime Studies of 130 nm and 65 nm CMOS Technologies for High-Energy Physics Experiments

    SciTech Connect

    Hoff, James R.; Deptuch, G. W.; Wu, Guoying; Gui, Ping

    2015-06-04

    The Long Baseline Neutrino Facility intends to use unprecedented volumes of liquid argon to fill a time projection chamber in an underground facility. Research is under way to place the electronics inside the cryostat. For reasons of efficiency and economics, the lifetimes of these circuits must be well in excess of 20 years. The principle mechanism for lifetime degradation of MOSFET devices and circuits operating at cryogenic temperatures is hot carrier degradation. Choosing a process technology that is, as much as possible, immune to such degradation and developing design techniques to avoid exposure to such damage are the goals. This, then, requires careful investigation and a basic understanding of the mechanisms that underlie hot carrier degradation and the secondary effects they cause in circuits. In this work, commercially available 130 nm and 65 nm nMOS transistors operating at cryogenic temperatures are investigated. Our results show that both technologies achieve the lifetimes required by the experiment. Minimal design changes are necessary in the case of the 130 nm process and no changes whatsoever are necessary for the 65 nm process.

  16. A novel pixel design with hybrid type isolation scheme for low dark current in CMOS image sensor

    NASA Astrophysics Data System (ADS)

    Choi, Sung Ho; Kim, Yi Tae; Oh, Min Seok; Park, Young Hwan; Cho, Jeong Jin; Jang, Young Heub; Han, Hyung Jun; Choi, Jong Won; Park, Ho Woo; Jung, Sang Il; Oh, Hoon Sang; Ahn, Jung Chak; Goto, Hiroshige; Choi, Chi Young; Roh, Yonghan

    2013-02-01

    New isolation scheme for CMOS image sensor pixel is proposed and its improved dark current performance is reported. It is well known that shallow trench isolation (STI) is one of major sources of dark current in imager pixel due to the existence of interfacial defects at STI/Si interface. On the account STI-free structure over the whole pixel area was previously reported for reducing dark current. As the size of pixel pitch is shrunk, however, it becomes increasingly difficult to isolate in-pixel transistors electrically without STI. In this work, we implemented hybrid type isolation scheme of removing STI around photodiode to suppress the dark current and remaining STI near transistors to guarantee the electrical isolation of transistors in pixel. It was successfully achieved that the dark current was significantly reduced by removing the STI around the photodiode together with normal operation of in-pixel transistors.

  17. Response of a hybrid pixel detector (MEDIPIX3) to different radiation sources for medical applications

    SciTech Connect

    Chumacero, E. Miguel; De Celis Alonso, B.; Martínez Hernández, M. I.; Vargas, G.; Moreno Barbosa, E.; Moreno Barbosa, F.

    2014-11-07

    The development in semiconductor CMOS technology has enabled the creation of sensitive detectors for a wide range of ionizing radiation. These devices are suitable for photon counting and can be used in imaging and tomography X-ray diagnostics. The Medipix[1] radiation detection system is a hybrid silicon pixel chip developed for particle tracking applications in High Energy Physics. Its exceptional features (high spatial and energy resolution, embedded ultra fast readout, different operation modes, etc.) make the Medipix an attractive device for applications in medical imaging. In this work the energy characterization of a third-generation Medipix chip (Medipix3) coupled to a silicon sensor is presented. We used different radiation sources (strontium 90, iron 55 and americium 241) to obtain the response curve of the hybrid detector as a function of energy. We also studied the contrast of the Medipix as a measure of pixel noise. Finally we studied the response to fluorescence X rays from different target materials (In, Pd and Cd) for the two data acquisition modes of the chip; single pixel mode and charge summing mode.

  18. Response of a hybrid pixel detector (MEDIPIX3) to different radiation sources for medical applications

    NASA Astrophysics Data System (ADS)

    Chumacero, E. Miguel; De Celis Alonso, B.; Martínez Hernández, M. I.; Vargas, G.; Moreno Barbosa, F.; Moreno Barbosa, E.

    2014-11-01

    The development in semiconductor CMOS technology has enabled the creation of sensitive detectors for a wide range of ionizing radiation. These devices are suitable for photon counting and can be used in imaging and tomography X-ray diagnostics. The Medipix[1] radiation detection system is a hybrid silicon pixel chip developed for particle tracking applications in High Energy Physics. Its exceptional features (high spatial and energy resolution, embedded ultra fast readout, different operation modes, etc.) make the Medipix an attractive device for applications in medical imaging. In this work the energy characterization of a third-generation Medipix chip (Medipix3) coupled to a silicon sensor is presented. We used different radiation sources (strontium 90, iron 55 and americium 241) to obtain the response curve of the hybrid detector as a function of energy. We also studied the contrast of the Medipix as a measure of pixel noise. Finally we studied the response to fluorescence X rays from different target materials (In, Pd and Cd) for the two data acquisition modes of the chip; single pixel mode and charge summing mode.

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

    SciTech Connect

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

    1999-06-01

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

  20. Radiation-enhanced gate-induced-drain-leakage current in the 130 nm partially-depleted SOI pMOSFET

    NASA Astrophysics Data System (ADS)

    Peng, Chao; Hu, Zhiyuan; Ning, Bingxu; Dai, Lihua; Bi, Dawei; Zhang, Zhengxuan

    2015-04-01

    The total ionizing dose (TID) effect of the pMOSFET from 130 nm partially-depleted silicon-on-insulator (PDSOI) is investigated. The data obtained from 60Co γ-ray irradiation experiments indicate that input/output (I/O) device is more susceptible to TID effect than the core device. An anomalous off-state leakage increase is observed for I/O pMOSFET when drain is biased at a high voltage after irradiation. It is proved that this radiation-induced leakage relates to the enhanced gate-induce-drain-leakage (GIDL). Both the radiation-induced interface traps at the gate-oxide/body interface and the oxide trapped charges in the buried oxide (BOX) are responsible for the growth of the leakage current. These conclusions are also verified by the TCAD simulations. The isothermal annealing can recover the leakage current to the pre-irradiation level.

  1. Dual-color polymer light-emitting pixels processed by hybrid inkjet printing

    NASA Astrophysics Data System (ADS)

    Chang, Shun-Chi; Bharathan, Jayesh; Helgeson, Roger; Wudl, Fred; Yang, Yang; Ramey, Michael B.; Reynolds, John R.

    1998-12-01

    We present a successful demonstration of controllable patterning of dual-color polymer light-emitting pixels using a hybrid inkjet printing technique. In this demonstration, the polymer buffer layer is a wide bandgap, blue emitting semiconducting polymer (PPP-NRt3+), prepared by the spin-casting technique. The inkjet printed layer is a red-orange semiconductor polymer, (MPS-PPV) which was printed onto the buffer layer.When a proper solvent was selected, MPS-PPV diffused into the buffer layer and efficient energy transfer took place from the PPP-NEt3+ to the MPS-PPV generating a red-orange photoluminescence and electroluminescence from the inkjet printed sites. Based on this principle, blue and orange-red dual-color polymer light-emitting pixels were fabricated on the same substrate. The use of this concept represents an entirely new technology for fabricating polymer multicolor displays with high-resolution, lateral patterning capability.

  2. Comparison of CCD, CMOS and Hybrid Pixel x-ray detectors: detection principle and data quality

    NASA Astrophysics Data System (ADS)

    Allé, P.; Wenger, E.; Dahaoui, S.; Schaniel, D.; Lecomte, C.

    2016-06-01

    We compare, from a crystallographic point of view, the data quality obtained using laboratory x-ray diffractometers equipped with a Molybdenum micro-source using different detector types: CCD, CMOS and XPAD hybrid pixel. First we give an overview of the working principle of these different detector types with a focus on their principal differences and their impact on the data quality. Then, using the example of an organic crystal, a comparison between the detector systems concerning the raw data statistics, the refinement agreement factors, the deformation electron density maps, and the residual density after multipolar refinement is presented. It is found that the data quality obtained with the XPAD detector is the best, even though the detection efficiency at the Mo energy (17.5 keV) is only 37% due to the Si-sensor layer thickness of 300 μm. Finally, we discuss the latest x-ray detector developments with an emphasis on the sensor material, where replacing Si by another material such as GaAs would yield detection efficiencies close to 100%, up to energies of 40 keV for hybrid pixel detectors.

  3. Modeling and analysis of hybrid pixel detector deficiencies for scientific applications

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

    Semiconductor hybrid pixel detectors often consist of a pixellated sensor layer bump bonded to a matching pixelated readout integrated circuit (ROIC). The sensor can range from high resistivity Si to III-V materials, whereas a Si CMOS process is typically used to manufacture the ROIC. Independent, device physics and electronic design automation (EDA) tools are used to determine sensor characteristics and verify functional performance of ROICs respectively with significantly different solvers. Some physics solvers provide the capability of transferring data to the EDA tool. However, single pixel transient simulations are either not feasible due to convergence difficulties or are prohibitively long. A simplified sensor model, which includes a current pulse in parallel with detector equivalent capacitor, is often used; even then, spice type top-level (entire array) simulations range from days to weeks. In order to analyze detector deficiencies for a particular scientific application, accurately defined transient behavioral models of all the functional blocks are required. Furthermore, various simulations, such as transient, noise, Monte Carlo, inter-pixel effects, etc. of the entire array need to be performed within a reasonable time frame without trading off accuracy. The sensor and the analog front-end can be modeling using a real number modeling language, as complex mathematical functions or detailed data can be saved to text files, for further top-level digital simulations. Parasitically aware digital timing is extracted in a standard delay format (sdf) from the pixel digital back-end layout as well as the periphery of the ROIC. For any given input, detector level worst-case and best-case simulations are performed using a Verilog simulation environment to determine the output. Each top-level transient simulation takes no more than 10-15 minutes. The impact of changing key parameters such as sensor Poissonian shot noise, analog front-end bandwidth, jitter due to

  4. Towards hybrid pixel detectors for energy-dispersive or soft X-ray photon science.

    PubMed

    Jungmann-Smith, J H; Bergamaschi, A; Brückner, M; Cartier, S; Dinapoli, R; Greiffenberg, D; Huthwelker, T; Maliakal, D; Mayilyan, D; Medjoubi, K; Mezza, D; Mozzanica, A; Ramilli, M; Ruder, Ch; Schädler, L; Schmitt, B; Shi, X; Tinti, G

    2016-03-01

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications at free-electron lasers and synchrotron light sources. The JUNGFRAU 0.4 prototype presented here is specifically geared towards low-noise performance and hence soft X-ray detection. The design, geometry and readout architecture of JUNGFRAU 0.4 correspond to those of other JUNGFRAU pixel detectors, which are charge-integrating detectors with 75 µm × 75 µm pixels. Main characteristics of JUNGFRAU 0.4 are its fixed gain and r.m.s. noise of as low as 27 e(-) electronic noise charge (<100 eV) with no active cooling. The 48 × 48 pixels JUNGFRAU 0.4 prototype can be combined with a charge-sharing suppression mask directly placed on the sensor, which keeps photons from hitting the charge-sharing regions of the pixels. The mask consists of a 150 µm tungsten sheet, in which 28 µm-diameter holes are laser-drilled. The mask is aligned with the pixels. The noise and gain characterization, and single-photon detection as low as 1.2 keV are shown. The performance of JUNGFRAU 0.4 without the mask and also in the charge-sharing suppression configuration (with the mask, with a `software mask' or a `cluster finding' algorithm) is tested, compared and evaluated, in particular with respect to the removal of the charge-sharing contribution in the spectra, the detection efficiency and the photon rate capability. Energy-dispersive and imaging experiments with fluorescence X-ray irradiation from an X-ray tube and a synchrotron light source are successfully demonstrated with an r.m.s. energy resolution of 20% (no mask) and 14% (with the mask) at 1.2 keV and of 5% at 13.3 keV. The performance evaluation of the JUNGFRAU 0.4 prototype suggests that this detection system could be the starting point for a future detector development effort for either applications in the soft X-ray energy regime or for an energy

  5. Modeling and Analysis of Hybrid Pixel Detector Deficiencies for Scientific Applications

    SciTech Connect

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

    2015-08-28

    Semiconductor hybrid pixel detectors often consist of a pixellated sensor layer bump bonded to a matching pixelated readout integrated circuit (ROIC). The sensor can range from high resistivity Si to III-V materials, whereas a Si CMOS process is typically used to manufacture the ROIC. Independent, device physics and electronic design automation (EDA) tools are used to determine sensor characteristics and verify functional performance of ROICs respectively with significantly different solvers. Some physics solvers provide the capability of transferring data to the EDA tool. However, single pixel transient simulations are either not feasible due to convergence difficulties or are prohibitively long. A simplified sensor model, which includes a current pulse in parallel with detector equivalent capacitor, is often used; even then, spice type top-level (entire array) simulations range from days to weeks. In order to analyze detector deficiencies for a particular scientific application, accurately defined transient behavioral models of all the functional blocks are required. Furthermore, various simulations, such as transient, noise, Monte Carlo, inter-pixel effects, etc. of the entire array need to be performed within a reasonable time frame without trading off accuracy. The sensor and the analog front-end can be modeling using a real number modeling language, as complex mathematical functions or detailed data can be saved to text files, for further top-level digital simulations. Parasitically aware digital timing is extracted in a standard delay format (sdf) from the pixel digital back-end layout as well as the periphery of the ROIC. For any given input, detector level worst-case and best-case simulations are performed using a Verilog simulation environment to determine the output. Each top-level transient simulation takes no more than 10-15 minutes. The impact of changing key parameters such as sensor Poissonian shot noise, analog front-end bandwidth, jitter due to

  6. Review of hybrid pixel detector readout ASICs for spectroscopic X-ray imaging

    NASA Astrophysics Data System (ADS)

    Ballabriga, R.; Alozy, J.; Campbell, M.; Frojdh, E.; Heijne, E. H. M.; Koenig, T.; Llopart, X.; Marchal, J.; Pennicard, D.; Poikela, T.; Tlustos, L.; Valerio, P.; Wong, W.; Zuber, M.

    2016-01-01

    Semiconductor detector readout chips with pulse processing electronics have made possible spectroscopic X-ray imaging, bringing an improvement in the overall image quality and, in the case of medical imaging, a reduction in the X-ray dose delivered to the patient. In this contribution we review the state of the art in semiconductor-detector readout ASICs for spectroscopic X-ray imaging with emphasis on hybrid pixel detector technology. We discuss how some of the key challenges of the technology (such as dealing with high fluxes, maintaining spectral fidelity, power consumption density) are addressed by the various ASICs. In order to understand the fundamental limits of the technology, the physics of the interaction of radiation with the semiconductor detector and the process of signal induction in the input electrodes of the readout circuit are described. Simulations of the process of signal induction are presented that reveal the importance of making use of the small pixel effect to minimize the impact of the slow motion of holes and hole trapping in the induced signal in high-Z sensor materials. This can contribute to preserve fidelity in the measured spectrum with relatively short values of the shaper peaking time. Simulations also show, on the other hand, the distortion in the energy spectrum due to charge sharing and fluorescence photons when the pixel pitch is decreased. However, using recent measurements from the Medipix3 ASIC, we demonstrate that the spectroscopic information contained in the incoming photon beam can be recovered by the implementation in hardware of an algorithm whereby the signal from a single photon is reconstructed and allocated to the pixel with the largest deposition.

  7. Lifetime studies of 130nm nMOS transistors intended for long-duration, cryogenic high-energy physics experiments.

    SciTech Connect

    Hoff, J.R.; Arora, R.; Cressler, J.D.; Deptuch, G.W.; Gui, P.; Lourenco, N.E.; Wu, G.; Yarema, R.J.; /Fermilab

    2011-12-01

    Future neutrino physics experiments intend to use unprecedented volumes of liquid argon to fill a time projection chamber in an underground facility. To increase performance, integrated readout electronics should work inside the cryostat. Due to the scale and cost associated with evacuating and filling the cryostat, the electronics will be unserviceable for the duration of the experiment. Therefore, the lifetimes of these circuits must be well in excess of 20 years. The principle mechanism for lifetime degradation of MOSFET devices and circuits operating at cryogenic temperatures is via hot carrier degradation. Choosing a process technology that is, as much as possible, immune to such degradation and developing design techniques to avoid exposure to such damage are the goals. This requires careful investigation and a basic understanding of the mechanisms that underlie hot carrier degradation and the secondary effects they cause in circuits. In this work, commercially available 130nm nMOS transistors operating at cryogenic temperatures are investigated. The results show that the difference in lifetime for room temperature operation and cryogenic operation for this process are not great and the lifetimes at both 300K and at 77K can be projected to more than 20 years at the nominal voltage (1.5V) for this technology.

  8. Investigating the degradation mechanisms caused by the TID effects in 130 nm PDSOI I/O NMOS

    NASA Astrophysics Data System (ADS)

    Peng, Chao; Hu, Zhiyuan; Zhang, Zhengxuan; Huang, Huixiang; Ning, Bingxu; Bi, Dawei

    2014-06-01

    This paper evaluates the radiation responses of 3.3 V I/O NMOSFETs from 130 nm partially-depleted silicon-on-insulator (PDSOI) technology. The data obtained from 60Co ionizing radiation experiments indicate that charge trapped in the shallow trench isolation, particularly at the bottom region of the trench oxide, should be the dominant contributor to the off-state drain-to-source leakage current under ON bias. The body doping profile and device dimension are two key factors affecting the performance degradation of the PDSOI transistors after radiation. Significant front gate threshold voltage shift is observed in the T-shape gate device, which is well known as the Radiation Induced Narrow Channel Effect (RINCE). The charge trapped in the buried oxide can induce large threshold voltage shift in the front gate transistor through coupling effect in the low body doping device. The coupling effect is evaluated through three-dimensional simulation. A degradation of the carrier mobility which relates to shallow trench isolation (STI) oxide trapped charge in the narrow channel device is also discussed.

  9. Bit Distribution and Reliability of High Density 1.5 V Ferroelectric Random Access Memory Embedded with 130 nm, 5 lm Copper Complementary Metal Oxide Semiconductor Logic

    NASA Astrophysics Data System (ADS)

    Udayakumar, K. R.; Boku, K.; Remack, K. A.; Rodriguez, J.; Summerfelt, S. R.; Celii, F. G.; Aggarwal, S.; Martin, J. S.; Hall, L.; Matz, L.; Rathsack, B.; McAdams, H.; Moise, T. S.

    2006-04-01

    High density embedded ferroelectric random access memory (FRAM), operable at 1.5 V, has been fabricated within a 130 nm, 5 lm Cu/fluorosilicate glass (FSG) logic process. To evaluate FRAM extendability to future process nodes, we have measured the bit distribution and reliability properties of arrays with varying individual capacitor areas ranging from 0.40 μm2 (130 nm node) to 0.15 μm2 (˜65 nm node). Wide signal margins, stable retention (≫10 years at 85 °C), and high endurance read/write cycling (≫1012 cycles) have been demonstrated, suggesting that reliable, high density FRAM can be realized.

  10. Advanced numerical modeling and hybridization techniques for third-generation infrared detector pixel arrays

    NASA Astrophysics Data System (ADS)

    Schuster, Jonathan

    Infrared (IR) detectors are well established as a vital sensor technology for military, defense and commercial applications. Due to the expense and effort required to fabricate pixel arrays, it is imperative to develop numerical simulation models to perform predictive device simulations which assess device characteristics and design considerations. Towards this end, we have developed a robust three-dimensional (3D) numerical simulation model for IR detector pixel arrays. We used the finite-difference time-domain technique to compute the optical characteristics including the reflectance and the carrier generation rate in the device. Subsequently, we employ the finite element method to solve the drift-diffusion equations to compute the electrical characteristics including the I(V) characteristics, quantum efficiency, crosstalk and modulation transfer function. We use our 3D numerical model to study a new class of detector based on the nBn-architecture. This detector is a unipolar unity-gain barrier device consisting of a narrow-gap absorber layer, a wide-gap barrier layer, and a narrow-gap collector layer. We use our model to study the underlying physics of these devices and to explain the anomalously long lateral collection lengths for photocarriers measured experimentally. Next, we investigate the crosstalk in HgCdTe photovoltaic pixel arrays employing a photon-trapping (PT) structure realized with a periodic array of pillars intended to provide broadband operation. The PT region drastically reduces the crosstalk; making the use of the PT structures not only useful to obtain broadband operation, but also desirable for reducing crosstalk, especially in small pitch detector arrays. Then, the power and flexibility of the nBn architecture is coupled with a PT structure to engineer spectrally filtering detectors. Last, we developed a technique to reduce the cost of large-format, high performance HgCdTe detectors by nondestructively screen-testing detector arrays prior

  11. Influence of electromagnetic interference on the analog part of hybrid Pixel detectors

    NASA Astrophysics Data System (ADS)

    Holik, M.; Kraus, V.; Granja, C.; Jakubek, J.; Georgiev, V.; Hromadka, M.; Skala, J.; Kubik, Z.

    2011-12-01

    The analog signal from the sensor of hybrid semiconductor pixel detectors is prone to electro-magnetic interference. The study and diagnosis of induced and common electro-magnetic coupling between the analog part and digital part of these devices is required. The influence of electro-magnetic interference was tested on the setup with a pixel detector Timepix or Medipix and a FITPix read-out interface. Measurements were carried out of external as well as internal interference. We evaluated the influence of both sources of electro-magnetic interference to the noise recorded by pixels. We measured the local spatial intensity distribution and frequency spectrum of the electro-magnetic field originating inside the readout chip during its own operation. In context of this test we exposed the detector chip to a locally generated artificial electro-magnetic field evaluating its sensitivity to induced interference. Consequently, the whole setup of the detector and read-out interface was exposed to a distant source of electro-magnetic radiation, during which we tested efficiency of the electro-magnetic shielding of various arrangements. Further, tests measured the coupling over power supply lines. In particular, the noise generated by the operation of the detector itself was determined. In addition, the detector sensitivity to deliberately induced noise was evaluated. By means of these tests weak points of the setup sensitive to the intrusion of electro-magnetic interference are revealed. When locations of susceptible places are identified proper methods can be applied to increase immunity of the detector setup against the electro-magnetic interference. Experiences gained are planned to be used in development of the EMI shielded version of the FITPIX interface shielded to electro-magnetic interference.

  12. XNAP: a hybrid pixel detector with nanosecond resolution for time resolved synchrotron radiation studies

    NASA Astrophysics Data System (ADS)

    Fajardo, P.; Baron, A. Q. R.; Dautet, H.; Davies, M.; Fischer, P.; Göttlicher, P.; Graafsma, H.; Hervé, C.; Rüffer, R.; Thil, C.

    2013-03-01

    The XNAP collaboration is constructing a hybrid pixel X-ray detector based on a monolithic silicon avalanche photodiode (APD) sensor array aiming at applications in synchrotron radiation facilities. The 2D detector is capable of identifying which individual electron bunch produces each detected X-ray photon, even when the storage ring operates in multibunch filling modes. This instrument is intended to be used in X-ray Photon Correlation Spectroscopy and Nuclear Resonance experiments and serve as a demonstrator for various kind of time resolved diffraction and scattering applications as well as a very high count rate device. The detector is a 1 kilopixel device with 280 μm pitch that implements both counting mode up to MHz frame rates and event-by-event readout with sub-nanosecond time resolution. The paper describes the detector design and some results obtained with small 4×4 pixel prototypes that have been built and measured to make and validate the most critical choices for the final detector.

  13. Dual-color polymer light-emitting pixels processed by hybrid inkjet printing

    NASA Astrophysics Data System (ADS)

    Chang, Shun-Chi; Bharathan, Jayesh; Yang, Yang; Helgeson, Roger; Wudl, Fred; Ramey, Michael B.; Reynolds, John R.

    1998-11-01

    A hybrid inkjet printing (HIJP) technology, which combines a pin-hole free polymer buffer layer and an inkjet printed polymer layer, allows the patterning of high quality polymer light-emitting devices. In this letter, we present a successful demonstration of controllable patterning of dual-color polymer light-emitting pixels using this HIJP technique. In this demonstration, the polymer buffer layer is a wide band gap, blue emitting semiconducting polymer prepared by the spin-casting technique. The inkjet printed layer is a red-orange semiconducting polymer which was printed onto the buffer layer. When a proper solvent was selected, the printed polymer diffused into the buffer layer and efficient energy transfer took place generating a red-orange photoluminescence and electroluminescence from the inkjet printed sites. Based on this principle, blue and orange-red dual-color polymer light-emitting pixels were fabricated on the same substrate. The use of this concept represents an entirely new technology for fabricating polymer multicolor displays with high-resolution, lateral patterning capability.

  14. Few-Layer MoS2-Organic Thin-Film Hybrid Complementary Inverter Pixel Fabricated on a Glass Substrate.

    PubMed

    Lee, Hee Sung; Shin, Jae Min; Jeon, Pyo Jin; Lee, Junyeong; Kim, Jin Sung; Hwang, Hyun Chul; Park, Eunyoung; Yoon, Woojin; Ju, Sang-Yong; Im, Seongil

    2015-05-13

    Few-layer MoS2-organic thin-film hybrid complementary inverters demonstrate a great deal of device performance with a decent voltage gain of ≈12, a few hundred pW power consumption, and 480 Hz switching speed. As fabricated on glass, this hybrid CMOS inverter operates as a light-detecting pixel as well, using a thin MoS2 channel. PMID:25641643

  15. Investigating the Inverse Square Law with the Timepix Hybrid Silicon Pixel Detector: A CERN [at] School Demonstration Experiment

    ERIC Educational Resources Information Center

    Whyntie, T.; Parker, B.

    2013-01-01

    The Timepix hybrid silicon pixel detector has been used to investigate the inverse square law of radiation from a point source as a demonstration of the CERN [at] school detector kit capabilities. The experiment described uses a Timepix detector to detect the gamma rays emitted by an [superscript 241]Am radioactive source at a number of different…

  16. Per pixel uncertainty modelling and its spatial representation on land cover maps obtained by hybrid classification.

    NASA Astrophysics Data System (ADS)

    Pons, Xavier; Sevillano, Eva; Moré, Gerard; Serra, Pere; Cornford, Dan; Ninyerola, Miquel

    2013-04-01

    The usage of remote sensing imagery combined with statistical classifiers to obtain categorical cartography is now common practice. As in many other areas of geographic information quality assessment, knowing the accuracy of these maps is crucial, and the spatialization of quality information is becoming ever more important for a large range of applications. Whereas some classifiers (e.g., maximum likelihood, linear discriminant analysis, naive Bayes, etc) permit the estimation and spatial representation of the uncertainty through a pixel level probabilistic estimator (and, from that, to compute a global accuracy estimator for the whole map), for other methods such a direct estimator does not exist. Regardless of the classification method applied, ground truth data is almost always available (to train the classifier and/or to compute the global accuracy and, usually, a confusion matrix). Our research is devoted to the development of a protocol to spatialize the error on a general framework based on the classifier parameters, and some ground truth reference data. In the methodological experiment presented here we provide an insight into uncertainty modelling for a hybrid classifier that combines unsupervised and supervised stages (implemented in the MiraMon GIS). In this work we describe what we believe is the first attempt to characterise pixel level uncertainty in a two stage classification process. We describe the model setup, show the preliminary results and identify future work that will be undertaken. The study area is a Landsat full frame located at the North-eastern region of the Iberian Peninsula. The six non-thermal bands + NDVI of a multi-temporal set of six geometrically and radiometrically corrected Landsat-5 images (between 2005 and 2007) were submitted to a hybrid classification process, together with some ancillary data (climate, slopes, etc). Training areas were extracted from the Land Cover Map of Catalonia (MCSC), a 0.5 m resolution map created by

  17. Hybrid pixel-waveform CdTe/CZT detector for use in an ultrahigh resolution MRI compatible SPECT system

    PubMed Central

    Cai, Liang; Meng, Ling-Jian

    2013-01-01

    In this paper, we will present a new small pixel CdTe/CZT detector for sub-500 μm resolution SPECT imaging application inside MR scanner based on a recently developed hybrid pixel-waveform (HPWF) readout circuitry. The HPWF readout system consists of a 2-D multi-pixel circuitry attached to the anode pixels to provide the X–Y positions of interactions, and a high-speed digitizer to read out the pulse-waveform induced on the cathode. The digitized cathode waveform could provide energy deposition information, precise timing and depth-of-interaction information for gamma ray interactions. Several attractive features with this HPWF detector system will be discussed in this paper. To demonstrate the performance, we constructed several prototype HPWF detectors with pixelated CZT and CdTe detectors of 2–5 mm thicknesses, connected to a prototype readout system consisting of energy-resolved photon-counting ASIC for readout anode pixels and an Agilent high-speed digitizer for digitizing the cathode signals. The performances of these detectors based on HPWF are discussed in this paper. PMID:24371365

  18. Hybrid pixel-waveform CdTe/CZT detector for use in an ultrahigh resolution MRI compatible SPECT system.

    PubMed

    Cai, Liang; Meng, Ling-Jian

    2013-02-01

    In this paper, we will present a new small pixel CdTe/CZT detector for sub-500 μm resolution SPECT imaging application inside MR scanner based on a recently developed hybrid pixel-waveform (HPWF) readout circuitry. The HPWF readout system consists of a 2-D multi-pixel circuitry attached to the anode pixels to provide the X-Y positions of interactions, and a high-speed digitizer to read out the pulse-waveform induced on the cathode. The digitized cathode waveform could provide energy deposition information, precise timing and depth-of-interaction information for gamma ray interactions. Several attractive features with this HPWF detector system will be discussed in this paper. To demonstrate the performance, we constructed several prototype HPWF detectors with pixelated CZT and CdTe detectors of 2-5 mm thicknesses, connected to a prototype readout system consisting of energy-resolved photon-counting ASIC for readout anode pixels and an Agilent high-speed digitizer for digitizing the cathode signals. The performances of these detectors based on HPWF are discussed in this paper. PMID:24371365

  19. Hybrid pixel-waveform CdTe/CZT detector for use in an ultrahigh resolution MRI compatible SPECT system

    NASA Astrophysics Data System (ADS)

    Cai, Liang; Meng, Ling-Jian

    2013-02-01

    In this paper, we will present a new small pixel CdTe/CZT detector for sub-500 μm resolution SPECT imaging application inside MR scanner based on a recently developed hybrid pixel-waveform (HPWF) readout circuitry. The HPWF readout system consists of a 2-D multi-pixel circuitry attached to the anode pixels to provide the X-Y positions of interactions, and a high-speed digitizer to read out the pulse-waveform induced on the cathode. The digitized cathode waveform could provide energy deposition information, precise timing and depth-of-interaction information for gamma ray interactions. Several attractive features with this HPWF detector system will be discussed in this paper. To demonstrate the performance, we constructed several prototype HPWF detectors with pixelated CZT and CdTe detectors of 2-5 mm thicknesses, connected to a prototype readout system consisting of energy-resolved photon-counting ASIC for readout anode pixels and an Agilent high-speed digitizer for digitizing the cathode signals. The performances of these detectors based on HPWF are discussed in this paper.

  20. VeloPix: the pixel ASIC for the LHCb upgrade

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  1. On the possibility to use semiconductive hybrid pixel detectors for study of radiation belt of the Earth.

    NASA Astrophysics Data System (ADS)

    Guskov, A.; Shelkov, G.; Smolyanskiy, P.; Zhemchugov, A.

    2016-02-01

    The scientific apparatus GAMMA-400 designed for study of electromagnetic and hadron components of cosmic rays will be launched to an elliptic orbit with the apogee of about 300 000 km and the perigee of about 500 km. Such a configuration of the orbit allows it to cross periodically the radiation belt and the outer part of magnetosphere. We discuss the possibility to use hybrid pixel detecters based on the Timepix chip and semiconductive sensors on board the GAMMA-400 apparatus. Due to high granularity of the sensor (pixel size is 55 mum) and possibility to measure independently an energy deposition in each pixel, such compact and lightweight detector could be a unique instrument for study of spatial, energy and time structure of electron and proton components of the radiation belt.

  2. Preliminary simulation study of a coincidence Avalanche Pixel Sensor

    NASA Astrophysics Data System (ADS)

    Vignetti, M. M.; Calmon, F.; Cellier, R.; Pittet, P.; Quiquerez, L.; Savoy-Navarro, A.

    2015-06-01

    In this paper a preliminary study of coincidence Avalanche Pixel Sensors (APiX) for High Energy Physics (HEP) applications is presented. In this preliminary work, some PEB prevention techniques found in literature have been studied by TCAD simulations adopting 2D Cylindrical geometrical models and 130nm CMOS process technological data.

  3. Beam test results of pixel triggerless prototypes for the PbarANDA MVD

    NASA Astrophysics Data System (ADS)

    Calvo, Daniela; De Remigis, Paolo; Filippi, Alessandra; Mazza, Giovanni; Rivetti, Angelo; Wheadon, Richard; De Mori, Francesca; Marcello, Simonetta; Zotti, Laura; Bianco, Simone; Zaunick, Hans-Georg; Brinkmann, Kai-Thomas; Quagli, Tommaso; Schnell, Robert

    2013-12-01

    Hybrid pixel and double sided silicon microstrip devices will equip the Micro Vertex Detector of the PbarANDA experiment. The most challenging request of the experiment is the continuous readout at the rate of 2×107 interactions/s. The detector is in an advanced R&D phase and pixel assemblies, composed of thinned epitaxial sensor read out by the custom chip prototype ToPix, developed in the 130 nm CMOS technology, were produced. The triggerless ASIC implements readout channels that are able to detect signals and transmit the information with a precise timestamp. It performs the energy loss measurement using the Time over Threshold technique, in the input range to about 50 fC. A dedicated testing bench allows the control and the readout of each single chip assembly. Two experimental setups were assembled for testing these first single chip prototypes with pions at CERN, T9, in August 2012. The first one is based on a pixel assembly positioned in the middle of a telescope composed of double sided silicon strips sensors. A 50 MHz clock signal synchronizes these two systems, the triggerless pixels and the strip detectors triggered by scintillation detectors. The second experimental setup is a tracking station housing four pixel assemblies. First results will be reported.

  4. Radiation hardness assessment of the charge-integrating hybrid pixel detector JUNGFRAU 1.0 for photon science.

    PubMed

    Jungmann-Smith, J H; Bergamaschi, A; Brückner, M; Cartier, S; Dinapoli, R; Greiffenberg, D; Jaggi, A; Maliakal, D; Mayilyan, D; Medjoubi, K; Mezza, D; Mozzanica, A; Ramilli, M; Ruder, Ch; Schädler, L; Schmitt, B; Shi, X; Tinti, G

    2015-12-01

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 10(4) photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 μm(2) pixels and is bump-bonded to a 320 μm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm(2). Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines. PMID:26724009

  5. Radiation hardness assessment of the charge-integrating hybrid pixel detector JUNGFRAU 1.0 for photon science

    SciTech Connect

    Jungmann-Smith, J. H. Bergamaschi, A.; Brückner, M.; Dinapoli, R.; Greiffenberg, D.; Jaggi, A.; Maliakal, D.; Mayilyan, D.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Ruder, Ch.; Schädler, L.; Schmitt, B.; Shi, X.; Tinti, G.; Cartier, S.; Medjoubi, K.

    2015-12-15

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 10{sup 4} photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 μm{sup 2} pixels and is bump-bonded to a 320 μm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm{sup 2}. Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines.

  6. Radiation hardness assessment of the charge-integrating hybrid pixel detector JUNGFRAU 1.0 for photon science

    NASA Astrophysics Data System (ADS)

    Jungmann-Smith, J. H.; Bergamaschi, A.; Brückner, M.; Cartier, S.; Dinapoli, R.; Greiffenberg, D.; Jaggi, A.; Maliakal, D.; Mayilyan, D.; Medjoubi, K.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Ruder, Ch.; Schädler, L.; Schmitt, B.; Shi, X.; Tinti, G.

    2015-12-01

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 104 photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 μm2 pixels and is bump-bonded to a 320 μm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm2. Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines.

  7. Hardware solutions for the 65k pixel X-ray camera module of 75 μm pixel size

    NASA Astrophysics Data System (ADS)

    Kasinski, K.; Maj, P.; Grybos, P.; Koziol, A.

    2016-02-01

    We present three hardware solutions designed for a detector module built with a 2 cm × 2 cm hybrid pixel detector built from a single 320 or 450 μ m thick silicon sensor designed and fabricated by Hamamatsu and two UFXC32k readout integrated circuits (128 × 256 pixels with 75μ m pitch, designed in CMOS 130 nm at AGH-UST). The chips work in a single photon counting mode and provide ultra-fast X-ray imaging. The presented hardware modules are designed according to requirements of various tests and applications: ṡDevice A: a fast and flexible system for tests with various radiation sources. ṡDevice B: a standalone, all-in-one imaging device providing three standard interfaces (USB 2.0, Ethernet, Camera Link) and up to 640 MB/s bandwidth. ṡDevice C: a prototype large-area imaging system. The paper shows the readout system structure for each case with highlighted circuit board designs with details on power distribution and cooling on both FR4 and LTCC (low temperature co-fired ceramic) based circuits.

  8. Observation of Peierls transition in nanowires (diameter approximately 130 nm) of the charge transfer molecule TTF-TCNQ synthesized by electric-field-directed growth.

    PubMed

    Sai, T Phanindra; Raychaudhuri, A K

    2010-01-29

    We report the growth of nanowires of the charge transfer complex tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) with diameters as low as 130 nm and show that such nanowires can show Peierls transitions at low temperatures. The wires of sub-micron length were grown between two prefabricated electrodes (with sub-micron gap) by vapor phase growth from a single source by applying an electric field between the electrodes during the growth process. The nanowires so grown show a charge transfer ratio approximately 0.57, which is close to that seen in bulk crystals. Below the transition the transport is strongly nonlinear and can be interpreted as originating from de-pinning of CDW that forms at the Peierls transition. PMID:20009165

  9. Observation of Peierls transition in nanowires (diameter~130 nm) of the charge transfer molecule TTF-TCNQ synthesized by electric-field-directed growth

    NASA Astrophysics Data System (ADS)

    Phanindra Sai, T.; Raychaudhuri, A. K.

    2010-01-01

    We report the growth of nanowires of the charge transfer complex tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) with diameters as low as 130 nm and show that such nanowires can show Peierls transitions at low temperatures. The wires of sub-micron length were grown between two prefabricated electrodes (with sub-micron gap) by vapor phase growth from a single source by applying an electric field between the electrodes during the growth process. The nanowires so grown show a charge transfer ratio ~0.57, which is close to that seen in bulk crystals. Below the transition the transport is strongly nonlinear and can be interpreted as originating from de-pinning of CDW that forms at the Peierls transition.

  10. Development of high data readout rate pixel module and detector hybridization at Fermilab

    SciTech Connect

    Sergio Zimmermann et al.

    2001-03-20

    This paper describes the baseline design and a variation of the pixel module to handle the data rate required for the BTeV experiment at Fermilab. The present prototype has shown good electrical performance characteristics. Indium bump bonding is proven to be capable of successful fabrication at 50 micron pitch on real detectors. For solder bumps at 50 micron pitch, much better results have been obtained with the fluxless PADS processed detectors. The results are adequate for our needs and our tests have validated it as a viable technology.

  11. K-edge imaging with the XPAD3 hybrid pixel detector, direct comparison of CdTe and Si sensors

    NASA Astrophysics Data System (ADS)

    Cassol, F.; Portal, L.; Graber-Bolis, J.; Perez-Ponce, H.; Dupont, M.; Kronland, C.; Boursier, Y.; Blanc, N.; Bompard, F.; Boudet, N.; Buton, C.; Clémens, J. C.; Dawiec, A.; Debarbieux, F.; Delpierre, P.; Hustache, S.; Vigeolas, E.; Morel, C.

    2015-07-01

    We investigate the improvement from the use of high-Z CdTe sensors for pre-clinical K-edge imaging with the hybrid pixel detectors XPAD3. We compare XPAD3 chips bump bonded to Si or CdTe sensors in identical experimental conditions. Image performance for narrow energy bin acquisitions and contrast-to-noise ratios of K-edge images are presented and compared. CdTe sensors achieve signal-to-noise ratios at least three times higher than Si sensors within narrow energy bins, thanks to their much higher detection efficiency. Nevertheless Si sensors provide better contrast-to-noise ratios in K-edge imaging when working at equivalent counting statistics, due to their better estimation of the attenuation coefficient of the contrast agent. Results are compared to simulated data in the case of the XPAD3/Si detector. Good agreement is observed when including charge sharing between pixels, which have a strong impact on contrast-to-noise ratios in K-edge images.

  12. K-edge imaging with the XPAD3 hybrid pixel detector, direct comparison of CdTe and Si sensors.

    PubMed

    Cassol, F; Portal, L; Graber-Bolis, J; Perez-Ponce, H; Dupont, M; Kronland, C; Boursier, Y; Blanc, N; Bompard, F; Boudet, N; Buton, C; Clémens, J C; Dawiec, A; Debarbieux, F; Delpierre, P; Hustache, S; Vigeolas, E; Morel, C

    2015-07-21

    We investigate the improvement from the use of high-Z CdTe sensors for pre-clinical K-edge imaging with the hybrid pixel detectors XPAD3. We compare XPAD3 chips bump bonded to Si or CdTe sensors in identical experimental conditions. Image performance for narrow energy bin acquisitions and contrast-to-noise ratios of K-edge images are presented and compared. CdTe sensors achieve signal-to-noise ratios at least three times higher than Si sensors within narrow energy bins, thanks to their much higher detection efficiency. Nevertheless Si sensors provide better contrast-to-noise ratios in K-edge imaging when working at equivalent counting statistics, due to their better estimation of the attenuation coefficient of the contrast agent. Results are compared to simulated data in the case of the XPAD3/Si detector. Good agreement is observed when including charge sharing between pixels, which have a strong impact on contrast-to-noise ratios in K-edge images. PMID:26133567

  13. A Hybrid Micro-Pixel Based Deep Ultraviolet Light-Emitting Diode Lamp

    NASA Astrophysics Data System (ADS)

    Hwang, Seongmo; Islam, Monirul; Zhang, Bin; Lachab, Mohamed; Dion, Joe; Heidari, Ahmad; Nazir, Haseeb; Adivarahan, Vinod; Khan, Asif

    2011-01-01

    We report on the room temperature electrical and optical characterization of a multichip light-emitting diode (LED) lamp with peak emission at 281 nm. Four pairs of micro-pixel LED arrays were connected in series to fabricate the lamp, which delivered a pulsed output power of 235 mW at 1.18 A (duty cycle ˜0.5%), and attained a high external quantum efficiency of 4.63%. Under dc operation, the maximum power achieved by this lamp was ˜20 mW at a drive current of 220 mA. The peak output power improved 1.62-fold after a thermoelectric cooler was added to the device packaging assembly.

  14. Investigation of hybrid pixel detector arrays by synchrotron-radiation imaging

    NASA Astrophysics Data System (ADS)

    Helfen, L.; Myagotin, A.; Pernot, P.; DiMichiel, M.; Mikulík, P.; Berthold, A.; Baumbach, T.

    2006-07-01

    Synchrotron-radiation imaging was applied to the non-destructive testing of detector devices during their development cycle. Transmission imaging known as computed laminography was used to examine the microstructure of the interconnections in order to investigate the perfection of technological steps necessary for hybrid detector production. A characterisation of the solder bump microstructure can reveal production flaws such as missing or misaligned bumps, voids in bumps or bridges and thus give valuable information about the bonding process.

  15. A 1 V 186-μW 50-MS/s 10-bit subrange SAR ADC in 130-nm CMOS process

    NASA Astrophysics Data System (ADS)

    Mingyuan, Yu; Ting, Li; Jiaqi, Yang; Shuangshuang, Zhang; Fujiang, Lin; Lin, He

    2016-07-01

    This paper presents a 10-bit 50-MS/s subrange successive-approximation register (SAR) analog-to-digital converter (ADC) composed of a 4-bit SAR coarse ADC and a 6-bit SAR fine ADC. In the coarse ADC, multi-comparator SAR architecture is used to reduce the digital logic propagation delay, and a traditional asynchronous SAR ADC with monotonic switching method is used as the fine ADC. With that combination, power dissipation also can be much reduced. Meanwhile, a modified SAR control logic is adopted in the fine ADC to speed up the conversion and other techniques, such as splitting capacitors array, are borrowed to reduce the power consumption. Fabricated with 1P8M 130-nm CMOS technology, the proposed SAR ADC achieves 51.6-dB signal to noise and distortion ratio (SNDR) and consumes 186 μW at 50 MS/s with a 1-V supply, resulting in a figure of merit (FOM) of 12 fJ/conversion-step. The core area is only 0.045 mm2. Project supported by the National Natural Science Foundation of China (Nos. 61204033, 61331015), the Fundamental Research Funds for the Central Universities (No. WK2100230015), and the Funds of Science and Technology on Analog Integrated Circuit Laboratory (No. 9140C090111150C09041).

  16. Cross/bar polymer electro-optic routing switch with broadband flatting spectral response over 130 nm: Principle, design and analysis

    NASA Astrophysics Data System (ADS)

    Zheng, Chuan-Tao; Zheng, Li-Hua; Luo, Qian-Qian; Liang, Lei; Ma, Chun-Sheng; Zhang, Da-Ming

    2013-05-01

    A novel non-resonance 2×2 polymer electro-optic (EO) switch with flatting spectral response is proposed by employing two-section reversed active Mach-Zehnder interferometers (MZIs), a passive middle directional coupler (M-DC) and two passive phase generating couplers (PGCs). Two crosstalk compensations are performed by optimizing the PGCs to broaden the spectrum under bar-state and optimizing the two active MZIs to broaden the spectrum under cross-state. The bar-state and cross-state voltages are 0 and ±4 V, respectively, with the two optimized MZI EO region lengths of 4068 and 5941 μm. Sufficiently considering wavelength dispersion of material and waveguide, a wide spectrum over 130 nm (1473-1603 nm) is achieved for dropping the crosstalk below -30 dB, and within this range, an insertion loss of 1.8-12.3 dB is observed. Under the same crosstalk level, this spectrum is over 2 times of that of the traditional 2×2 MZI switch (60 nm) based on the same materials. This broadband 2×2 switch is more attractive than our previously reported broadband 1×1 switch due to cross/bar routing operations other than simple ON/OFF functions.

  17. Visible and ultraviolet /800-130 nm/ extinction of vapor-condensed silicate, carbon, and silicon carbide smokes and the interstellar extinction curve

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.

    1980-01-01

    The extinction curves from 800 to 130 nm (1.25-7.7/micron) of amorphous silicate smokes nominally of olivine and pyroxene composition, carbon smokes, and crystalline SiC smokes are presented. The SiC smoke occurred in the low-temperature (beta) cubic structural form. The SiC smoke showed an absorption edge which occurred at significantly longer wavelengths than the calculated extinction profile of the hexagonal SiC form previously used to calculate the interstellar extinction profile. Neither SiC nor amorphous silicates show an extinction band similar to the observed 6.6/micron astronomical extinction band. The infrared absorption peaks for the silicate and SiC samples near 10 microns and 11-13 microns, respectively, were also measured. The ultraviolet to infrared extinction ratio for the amorphous silicate samples is similar to the observed astronomical extinction ratio. The measured extinction ratios for SiC smokes are significantly below the interstellar extinction ratio. The extinction peak of the carbon smokes occurred at 4.0 and 4.25/micron, for samples of mean radii 13 and 6 nm, respectively. The extinction profile is distinctly different from that predicted for graphite grains of the same size, and is similar to that predicted for glassy carbon grains.

  18. Pixel frontend electronics in a radiation hard technology for hybrid and monolithic applications

    SciTech Connect

    Pengg, F. |; Campbell, M.; Heijne, E.H.M.; Snoeys, W.

    1996-06-01

    Pixel detector readout cells have been designed in the radiation hard DMILL technology and their characteristics evaluated before and after irradiation to 14Mrad. The test chip consists of two blocks of six readout cells each. Two different charge amplifiers are implemented, one of them using a capacitive feedback loop, the other the fast signal charge transfer to a high impedance integrating node. The measured equivalent noise charge is 110e{sup {minus}}r.m.s. before and 150e{sup {minus}}r.m.s. after irradiation. With a discriminator threshold set to 5000e{sup {minus}}, which reduces for the same bias setting to 400e{sup {minus}} after irradiation, the threshold variation is 300e{sup {minus}}r.m.s. and 250e{sup {minus}}r.m.s. respectively. The time walk is 40ns before and after irradiation. The use of this SOI technology for monolithic integration of electronics and detector in one substrate is under investigation.

  19. Hybrid Pixel-Based Method for Cardiac Ultrasound Fusion Based on Integration of PCA and DWT

    PubMed Central

    Sulaiman, Puteri Suhaiza; Wirza, Rahmita; Dimon, Mohd Zamrin; Khalid, Fatimah; Moosavi Tayebi, Rohollah

    2015-01-01

    Medical image fusion is the procedure of combining several images from one or multiple imaging modalities. In spite of numerous attempts in direction of automation ventricle segmentation and tracking in echocardiography, due to low quality images with missing anatomical details or speckle noises and restricted field of view, this problem is a challenging task. This paper presents a fusion method which particularly intends to increase the segment-ability of echocardiography features such as endocardial and improving the image contrast. In addition, it tries to expand the field of view, decreasing impact of noise and artifacts and enhancing the signal to noise ratio of the echo images. The proposed algorithm weights the image information regarding an integration feature between all the overlapping images, by using a combination of principal component analysis and discrete wavelet transform. For evaluation, a comparison has been done between results of some well-known techniques and the proposed method. Also, different metrics are implemented to evaluate the performance of proposed algorithm. It has been concluded that the presented pixel-based method based on the integration of PCA and DWT has the best result for the segment-ability of cardiac ultrasound images and better performance in all metrics. PMID:26089965

  20. Hybrid Pixel-Based Method for Cardiac Ultrasound Fusion Based on Integration of PCA and DWT.

    PubMed

    Mazaheri, Samaneh; Sulaiman, Puteri Suhaiza; Wirza, Rahmita; Dimon, Mohd Zamrin; Khalid, Fatimah; Moosavi Tayebi, Rohollah

    2015-01-01

    Medical image fusion is the procedure of combining several images from one or multiple imaging modalities. In spite of numerous attempts in direction of automation ventricle segmentation and tracking in echocardiography, due to low quality images with missing anatomical details or speckle noises and restricted field of view, this problem is a challenging task. This paper presents a fusion method which particularly intends to increase the segment-ability of echocardiography features such as endocardial and improving the image contrast. In addition, it tries to expand the field of view, decreasing impact of noise and artifacts and enhancing the signal to noise ratio of the echo images. The proposed algorithm weights the image information regarding an integration feature between all the overlapping images, by using a combination of principal component analysis and discrete wavelet transform. For evaluation, a comparison has been done between results of some well-known techniques and the proposed method. Also, different metrics are implemented to evaluate the performance of proposed algorithm. It has been concluded that the presented pixel-based method based on the integration of PCA and DWT has the best result for the segment-ability of cardiac ultrasound images and better performance in all metrics. PMID:26089965

  1. A 10 MS/s 8-bit charge-redistribution ADC for hybrid pixel applications in 65 m CMOS

    NASA Astrophysics Data System (ADS)

    Kishishita, Tetsuichi; Hemperek, Tomasz; Krüger, Hans; Koch, Manuel; Germic, Leonard; Wermes, Norbert

    2013-12-01

    The design and measurement results of an 8-bit SAR ADC, based on a charge-redistribution DAC, are presented. This ADC is characterized by superior power efficiency and small area, realized by employing a lateral metal-metal capacitor array and a dynamic two-stage comparator. To avoid the need for a high-speed clock and its associated power consumption, an asynchronous logic was implemented in a logic control cell. A test chip has been developed in a 65 nm CMOS technology, including eight ADC channels with different layout flavors of the capacitor array, a transimpedance amplifier as a signal input structure, a serializer, and a custom-made LVDS driver for data transmission. The integral (INL) and differential (DNL) nonlinearities are measured below 0.5 LSB and 0.8 LSB, respectively, for the best channel operating at a sampling frequency of 10 MS/s. The area occupies 40 μm×70 μm for one ADC channel. The power consumption is estimated as 4 μW at 1 MS/s and 38 μW at 10 MS/s with a supply rail of 1.2 V. These excellent performance features and the natural radiation hardness of the design, due to the thin gate oxide thickness of transistors, are very interesting for front-end electronics ICs of future hybrid-pixel detector systems.

  2. Investigating the inverse square law with the Timepix hybrid silicon pixel detector: a CERN@school demonstration experiment

    NASA Astrophysics Data System (ADS)

    Whyntie, T.; Parker, B.

    2013-05-01

    The Timepix hybrid silicon pixel detector has been used to investigate the inverse square law of radiation from a point source as a demonstration of the CERN@school detector kit capabilities. The experiment described uses a Timepix detector to detect the gamma rays emitted by an 241Am radioactive source at a number of different distances. Datasets for each distance were collected, processed and analysed using the Pixelman software suite and CERN’s ROOT analysis software. The inverse square law approximation describes the data well, and so by following the experiment students can make the connection between the relevant elements of the physics curriculum and cutting-edge physics research. Additionally, an analytic model of the detector geometry is used to provide a comparable description of the data without the need for approximations. Such an exercise is typical of the kind of extension activity that can pave the way to students and teachers going beyond the physics curriculum and performing their own research with CERN@school.

  3. Success and failure of dead-time models as applied to hybrid pixel detectors in high-flux applications

    PubMed Central

    Sobott, B. A.; Broennimann, Ch.; Schmitt, B.; Trueb, P.; Schneebeli, M.; Lee, V.; Peake, D. J.; Elbracht-Leong, S.; Schubert, A.; Kirby, N.; Boland, M. J.; Chantler, C. T.; Barnea, Z.; Rassool, R. P.

    2013-01-01

    The performance of a single-photon-counting hybrid pixel detector has been investigated at the Australian Synchrotron. Results are compared with the body of accepted analytical models previously validated with other detectors. Detector functionals are valuable for empirical calibration. It is shown that the matching of the detector dead-time with the temporal synchrotron source structure leads to substantial improvements in count rate and linearity of response. Standard implementations are linear up to ∼0.36 MHz pixel−1; the optimized linearity in this configuration has an extended range up to ∼0.71 MHz pixel−1; these are further correctable with a transfer function to ∼1.77 MHz pixel−1. This new approach has wide application both in high-accuracy fundamental experiments and in standard crystallographic X-ray fluorescence and other X-ray measurements. The explicit use of data variance (rather than N 1/2 noise) and direct measures of goodness-of-fit (χr 2) are introduced, raising issues not encountered in previous literature for any detector, and suggesting that these inadequacies of models may apply to most detector types. Specifically, parametrization of models with non-physical values can lead to remarkable agreement for a range of count-rate, pulse-frequency and temporal structure. However, especially when the dead-time is near resonant with the temporal structure, limitations of these classical models become apparent. Further, a lack of agreement at extreme count rates was evident. PMID:23412493

  4. High-contrast X-ray micro-tomography of low attenuation samples using large area hybrid semiconductor pixel detector array of 10 × 5 Timepix chips

    NASA Astrophysics Data System (ADS)

    Karch, J.; Krejci, F.; Bartl, B.; Dudak, J.; Kuba, J.; Kvacek, J.; Zemlicka, J.

    2016-01-01

    State-of-the-art hybrid pixel semiconductor detectors provide excellent imaging properties such as unlimited dynamic range, high spatial resolution, high frame rate and energy sensitivity. Nevertheless, a limitation in the use of these devices for imaging has been the small sensitive area of a few square centimetres. In the field of microtomography we make use of a large area pixel detector assembled from 50 Timepix edgeless chips providing fully sensitive area of 14.3 × 7.15 cm2. We have successfully demonstrated that the enlargement of the sensitive area enables high-quality tomographic measurements of whole objects with high geometrical magnification without any significant degradation in resulting reconstructions related to the chip tilling and edgeless sensor technology properties. The technique of micro-tomography with the newly developed large area detector is applied for samples formed by low attenuation, low contrast materials such a seed from Phacelia tanacetifolia, a charcoalified wood sample and a beeswax seal sample.

  5. Hybrid method of strain estimation in optical coherence elastography using combined sub-wavelength phase measurements and supra-pixel displacement tracking.

    PubMed

    Zaitsev, Vladimir Y; Matveyev, Alexander L; Matveev, Lev A; Gelikonov, Grigory V; Gubarkova, Ekaterina V; Gladkova, Natalia D; Vitkin, Alex

    2016-05-01

    A novel hybrid method which combines sub-wavelength-scale phase measurements and pixel-scale displacement tracking for robust strain mapping in compressional optical coherence elastography is proposed. Unlike majority of OCE methods it does not rely on initial reconstruction of displacements and does not suffer from the phase-wrapping problem for super-wavelength displacements. Its robustness is enabled by direct fitting of local phase gradients obviating the necessity of phase unwrapping and error-prone numerical differentiation. Furthermore, axial displacements significantly exceeding not only the optical wavelength, but pixel scales (i.e., multiple wavelengths) can be efficiently tracked and compensated. This feature strongly reduces errors in phase-gradient estimation and ensures high robustness with respect to both additive and decorrelation noises. Illustration of exceptionally high tolerance of the proposed method to noises: contrast of only 25% in the stiffness of the layers is clearly seen in the strain map even for equal intensities of the OCT signal and additive noise (SNR = 0 dB). PMID:27159850

  6. PIXEL PUSHER

    NASA Technical Reports Server (NTRS)

    Stanfill, D. F.

    1994-01-01

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

  7. PIXEL 2010 - A Résumé

    NASA Astrophysics Data System (ADS)

    Wermes, N.

    2011-09-01

    The Pixel 2010 conference focused on semiconductor pixel detectors for particle tracking/vertexing as well as for imaging, in particular for synchrotron light sources and XFELs. The big LHC hybrid pixel detectors have impressively started showing their capabilities. X-ray imaging detectors, also using the hybrid pixel technology, have greatly advanced the experimental possibilities for diffraction experiments. Monolithic or semi-monolithic devices like CMOS active pixels and DEPFET pixels have now reached a state such that complete vertex detectors for RHIC and superKEKB are being built with these technologies. Finally, new advances towards fully monolithic active pixel detectors, featuring full CMOS electronics merged with efficient signal charge collection, exploiting standard CMOS technologies, SOI and/or 3D integration, show the path for the future. This résumé attempts to extract the main statements of the results and developments presented at this conference.

  8. A low-noise 15-μm pixel-pitch 640×512 hybrid InGaAs image sensor for night vision

    NASA Astrophysics Data System (ADS)

    Guellec, Fabrice; Dubois, Sébastien; de Borniol, Eric; Castelein, Pierre; Martin, Sébastien; Guiguet, Romain; Tchagaspanian, Micha"l.; Rouvié, Anne; Bois, Philippe

    2012-03-01

    Hybrid InGaAs focal plane arrays are very interesting for night vision because they can benefit from the nightglow emission in the Short Wave Infrared band. Through a collaboration between III-V Lab and CEA-Léti, a 640x512 InGaAs image sensor with 15μm pixel pitch has been developed. The good crystalline quality of the InGaAs detectors opens the door to low dark current (around 20nA/cm2 at room temperature and -0.1V bias) as required for low light level imaging. In addition, the InP substrate can be removed to extend the detection range towards the visible spectrum. A custom readout IC (ROIC) has been designed in a standard CMOS 0.18μm technology. The pixel circuit is based on a capacitive transimpedance amplifier (CTIA) with two selectable charge-to-voltage conversion gains. Relying on a thorough noise analysis, this input stage has been optimized to deliver low-noise performance in high-gain mode with a reasonable concession on dynamic range. The exposure time can be maximized up to the frame period thanks to a rolling shutter approach. The frame rate can be up to 120fps or 60fps if the Correlated Double Sampling (CDS) capability of the circuit is enabled. The first results show that the CDS is effective at removing the very low frequency noise present on the reference voltage in our test setup. In this way, the measured total dark noise is around 90 electrons in high-gain mode for 8.3ms exposure time. It is mainly dominated by the dark shot noise for a detector temperature settling around 30°C when not cooled. The readout noise measured with shorter exposure time is around 30 electrons for a dynamic range of 71dB in high-gain mode and 108 electrons for 79dB in low-gain mode.

  9. The FE-I4 Pixel Readout Chip and the IBL Module

    SciTech Connect

    Barbero, Marlon; Arutinov, David; Backhaus, Malte; Fang, Xiao-Chao; Gonella, Laura; Hemperek, Tomasz; Karagounis, Michael; Hans, Kruger; Kruth, Andre; Wermes, Norbert; Breugnon, Patrick; Fougeron, Denis; Gensolen, Fabrice; Menouni, Mohsine; Rozanov, Alexander; Beccherle, Roberto; Darbo, Giovanni; Caminada, Lea; Dube, Sourabh; Fleury, Julien; Gnani, Dario; /LBL, Berkeley /NIKHEF, Amsterdam /Gottingen U. /SLAC

    2012-05-01

    FE-I4 is the new ATLAS pixel readout chip for the upgraded ATLAS pixel detector. Designed in a CMOS 130 nm feature size process, the IC is able to withstand higher radiation levels compared to the present generation of ATLAS pixel Front-End FE-I3, and can also cope with higher hit rate. It is thus suitable for intermediate radii pixel detector layers in the High Luminosity LHC environment, but also for the inserted layer at 3.3 cm known as the 'Insertable B-Layer' project (IBL), at a shorter timescale. In this paper, an introduction to the FE-I4 will be given, focusing on test results from the first full size FE-I4A prototype which has been available since fall 2010. The IBL project will be introduced, with particular emphasis on the FE-I4-based module concept.

  10. The CMS pixel system

    NASA Astrophysics Data System (ADS)

    Bortoletto, Daniela; CMS Collaboration

    2007-09-01

    The CMS hybrid pixel detector is located at the core of the CMS tracker and will contribute significantly to track and vertex reconstruction. The detector is subdivided into a three-layer barrel, and two end-cap disks on either side of the interaction region. The system operating in the 25-ns beam crossing time of the LHC must be radiation hard, low mass, and robust. The construction of the barrel modules and the forward disks has started after extensive R&D. The status of the project is reported.

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

    PubMed

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

    2011-10-01

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

  12. ATLAS pixel IBL modules construction experience and developments for future upgrade

    NASA Astrophysics Data System (ADS)

    Gaudiello, A.

    2015-10-01

    The first upgrade of the ATLAS Pixel Detector is the Insertable B-Layer (IBL), installed in May 2014 in the core of ATLAS. Two different silicon sensor technologies, planar n-in-n and 3D, are used. Sensors are connected with the new generation 130 nm IBM CMOS FE-I4 read-out chip via solder bump-bonds. Production quality control tests were set up to verify and rate the performance of the modules before integration into staves. An overview of module design and construction, the quality control results and production yield will be discussed, as well as future developments foreseen for future detector upgrades.

  13. Pixel Perfect

    SciTech Connect

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

    2005-09-01

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

  14. Characterization of the ePix100 prototype: a front-end ASIC for second-generation LCLS integrating hybrid pixel detectors

    NASA Astrophysics Data System (ADS)

    Caragiulo, P.; Dragone, A.; Markovic, B.; Herbst, R.; Nishimura, K.; Reese, B.; Herrmann, S.; Hart, P.; Blaj, G.; Segal, J.; Tomada, A.; Hasi, J.; Carini, G.; Kenney, C.; Haller, G.

    2014-09-01

    ePix100 is the first variant of a novel class of integrating pixel ASICs architectures optimized for the processing of signals in second generation LINAC Coherent Light Source (LCLS) X-Ray cameras. ePix100 is optimized for ultra-low noise application requiring high spatial resolution. ePix ASICs are based on a common platform composed of a random access analog matrix of pixel with global shutter, fast parallel column readout, and dedicated sigma-delta analog to digital converters per column. The ePix100 variant has 50μmx50μm pixels arranged in a 352x384 matrix, a resolution of 50e- r.m.s. and a signal range of 35fC (100 photons at 8keV). In its final version it will be able to sustain a frame rate of 1kHz. A first prototype has been fabricated and characterized and the measurement results are reported here.

  15. MediSPECT: Single photon emission computed tomography system for small field of view small animal imaging based on a CdTe hybrid pixel detector

    NASA Astrophysics Data System (ADS)

    Accorsi, R.; Autiero, M.; Celentano, L.; Chmeissani, M.; Cozzolino, R.; Curion, A. S.; Frallicciardi, P.; Laccetti, P.; Lanza, R. C.; Lauria, A.; Maiorino, M.; Marotta, M.; Mettivier, G.; Montesi, M. C.; Riccio, P.; Roberti, G.; Russo, P.

    2007-02-01

    We describe MediSPECT, a new scanner developed at University and INFN Napoli, for SPECT studies on small animals with a small field of view (FOV) and high spatial resolution. The CdTe pixel detector (a 256×256 matrix of 55 μm square pixels) operating in single photon counting for detection of gamma-rays with low and medium energy (e.g. 125I, 27-35 keV, 99mTc, 140 keV), is bump bonded to the Medipix2 readout chip. The FOV of the MediSPECT scanner with a coded aperture mask collimator ranges from 6.3 mm (system spatial resolution 110 μm at 27-35 keV) to 24.3 mm. With a 0.30 mm pinhole the FOV ranges from 2.4 to 29 mm (where the system spatial resolution is 1.0 mm at 27-35 keV and 2.0 mm at 140 keV). MediSPECT will be used for in vivo imaging of small organs or tissue structures in mouse, e.g., brain, thyroid, heart or tumor.

  16. Low area 4-bit 5 MS/s flash-type digitizer for hybrid-pixel detectors - Design study in 180 nm and 40 nm CMOS

    NASA Astrophysics Data System (ADS)

    Otfinowski, Piotr; Grybos, Pawel

    2015-11-01

    We report on the design of a 4-bit flash ADC with dynamic offset correction dedicated to measurement systems based on a pixel architecture. The presented converter was manufactured in two CMOS technologies: widespread and economical 180 nm and modern 40 nm process. The designs are optimized for the lowest area occupancy resulting in chip areas of 160×55 μm2 and 35×25 μm2. The experimental results indicate integral nonlinearity of +0.35/-0.21 LSB and +0.28/-0.25 LSB and power consumption of 52 μW and 17 μW at 5 MS/s for the prototypes in 180 nm and 40 nm technologies respectively.

  17. SOI monolithic pixel detector

    NASA Astrophysics Data System (ADS)

    Miyoshi, T.; Ahmed, M. I.; Arai, Y.; Fujita, Y.; Ikemoto, Y.; Takeda, A.; Tauchi, K.

    2014-05-01

    We are developing monolithic pixel detector using fully-depleted (FD) silicon-on-insulator (SOI) pixel process technology. The SOI substrate is high resistivity silicon with p-n junctions and another layer is a low resistivity silicon for SOI-CMOS circuitry. Tungsten vias are used for the connection between two silicons. Since flip-chip bump bonding process is not used, high sensor gain in a small pixel area can be obtained. In 2010 and 2011, high-resolution integration-type SOI pixel sensors, DIPIX and INTPIX5, have been developed. The characterizations by evaluating pixel-to-pixel crosstalk, quantum efficiency (QE), dark noise, and energy resolution were done. A phase-contrast imaging was demonstrated using the INTPIX5 pixel sensor for an X-ray application. The current issues and future prospect are also discussed.

  18. Detective quantum efficiency for photon-counting hybrid pixel detectors in the tender X-ray domain: application to Medipix3RX.

    PubMed

    Rinkel, Jean; Magalhães, Debora; Wagner, Franz; Meneau, Florian; Cesar Vicentin, Flavio

    2016-01-01

    Synchrotron-radiation-based X-ray imaging techniques using tender X-rays are facing a growing demand, in particular to probe the K absorption edges of low-Z elements. Here, a mathematical model has been developed for estimating the detective quantum efficiency (DQE) at zero spatial frequency in the tender X-ray energy range for photon-counting detectors by taking into account the influence of electronic noise. The experiments were carried out with a Medipix3RX ASIC bump-bonded to a 300 µm silicon sensor at the Soft X-ray Spectroscopy beamline (D04A-SXS) of the Brazilian Synchrotron Light Laboratory (LNLS, Campinas, Brazil). The results show that Medipix3RX can be used to develop new imaging modalities in the tender X-ray range for energies down to 2 keV. The efficiency and optimal DQE depend on the energy and flux of the photons. The optimal DQE values were found in the 7.9-8.6 keV photon energy range. The DQE deterioration for higher energies due to the lower absorption efficiency of the sensor and for lower energies due to the electronic noise has been quantified. The DQE for 3 keV photons and 1 × 10(4) photons pixel(-1) s(-1) is similar to that obtained with 19 keV photons. Based on our model, the use of Medipix3RX could be extended down to 2 keV which is crucial for coming applications in imaging techniques at modern synchrotron sources. PMID:26698065

  19. PixelLearn

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  20. Moving from pixels to parcels: Modeling agricultural scenarios in the northern Great Plains using a hybrid raster- and vector-based approach

    NASA Astrophysics Data System (ADS)

    Sohl, T.; Wika, S.; Dornbierer, J.; Sayler, K. L.; Quenzer, R.

    2015-12-01

    Policy and economic driving forces have resulted in a higher demand for biofuel feedstocks in recent years, resulting in substantial increases in cultivated cropland in the northern Great Plains. A cellulosic-based biofuel industry could potentially further impact the region, with grassland and marginal agricultural land converted to perennial grasses or other feedstocks. Scenarios of projected land-use change are needed to enable regional stakeholders to plan for the potential consequences of expanded agricultural activity. Land-use models used to produce spatially explicit scenarios are typically raster-based and are poor at representing ownership units on which land-use change is based. This work describes a hybrid raster/vector-based modeling approach for modeling scenarios of agricultural change in the northern Great Plains. Regional scenarios of agricultural change from 2012 to 2050 were constructed, based partly on the U.S. Department of Energy's Billion Ton Update. Land-use data built from the 2012 Cropland Data Layer and the 2011 National Land Cover Database was used to establish initial conditions. Field boundaries from the U.S. Department of Agriculture's Common Land Unit dataset were used to establish ownership units. A modified version of the U.S. Geological Survey's Forecasting Scenarios of land-use (FORE-SCE) model was used to ingest vector-based field boundaries to facilitate the modeling of a farmer's choice of land use for a given year, while patch-based raster methodologies were used to represent expansion of urban/developed lands and other land use conversions. All modeled data were merged to a common raster dataset representing annual land use from 2012 to 2050. The hybrid modeling approach enabled the use of traditional, raster-based methods while integrating vector-based data to represent agricultural fields and other ownership-based units upon which land-use decisions are typically made.

  1. High density pixel array

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  2. Pixel-One

    NASA Astrophysics Data System (ADS)

    Pedichini, F.; Di Paola, A.; Testa, V.

    2010-07-01

    The early future of astronomy will be dominated by Extremely Large Telescopes where the focal lengths will be of the order of several hundred meters. This yields focal plane sizes of roughly one square meter to obtain a field of view of about 5 x 5 arcmin. When operated in seeing limited mode this field is correctly sampled with 1x1mm pixels. Such a sampling can be achieved using a peculiar array of tiny CMOS active photodiodes illuminated through microlenses or lightpipes. If the photodiode is small enough and utilizes the actual pixel technology, its dark current can be kept well below the sky background photocurrent, thus avoiding the use of cumbersome cryogenics systems. An active smart electronics will manage each pixel up to the A/D conversion and data transfer. This modular block is the Pixel-One. A 30x30 mm tile filled with 1000 Pixel-Ones could be the basic unit to mosaic very large focal planes. By inserting dispersion elements inside the optical path of the lenslet array one could also produce a low dispersed spectrum of each focal plane sub-aperture and, by using an array of few smart photodiodes, also get multi-wavelength information in the optical band for each equivalent focal plane pixel. An application to the E-ELT is proposed.

  3. Development of pixel detectors for SSC vertex tracking

    SciTech Connect

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

    1991-04-01

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

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

    SciTech Connect

    Cardoso, G.

    2001-03-08

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

  5. Controlled pixelation of inverse opaline structures towards reflection-mode displays.

    PubMed

    Lee, Su Yeon; Kim, Shin-Hyun; Hwang, Hyerim; Sim, Jae Young; Yang, Seung-Man

    2014-04-16

    Pixelated inverse opals with red, green, and blue colors were prepared by hybridizing convective assembly of colloidal particles and photolithography techniques. The brilliant structural colors, high mechanical stability, and small feature size of the pixels were simultaneously accomplished, thereby providing color reflectors potentially useful for display devices. Moreover, this hybridized method provides a general means to create multi-colored photonic crystals. PMID:24458607

  6. Characterization of Depleted Monolithic Active Pixel detectors implemented with a high-resistive CMOS technology

    NASA Astrophysics Data System (ADS)

    Kishishita, T.; Hemperek, T.; Rymaszewski, P.; Hirono, T.; Krüger, H.; Wermes, N.

    2016-07-01

    We present the recent development of DMAPS (Depleted Monolithic Active Pixel Sensor), implemented with a Toshiba 130 nm CMOS process. Unlike in the case of standard MAPS technologies which are based on an epi-layer, this process provides a high-resistive substrate that enables larger signal and faster charge collection by drift in a 50 - 300 μm thick depleted layer. Since this process also enables the use of deep n-wells to isolate the collection electrodes from the thin active device layer, NMOS and PMOS transistors are available for the readout electronics in each pixel cell. In order to characterize the technology, we implemented a simple three transistor readout with a variety of pixel pitches and input FET sizes. This layout variety gives us a clue on sensor characteristics for future optimization, such as the input detector capacitance or leakage current. In the initial measurement, the radiation spectra were obtained from 55Fe with an energy resolution of 770 eV (FWHM) and 90Sr with the MVP of 4165 e-.

  7. Development of Gated Pinned Avalanche Photodiode Pixels for High-Speed Low-Light Imaging.

    PubMed

    Resetar, Tomislav; De Munck, Koen; Haspeslagh, Luc; Rosmeulen, Maarten; Süss, Andreas; Puers, Robert; Van Hoof, Chris

    2016-01-01

    This work explores the benefits of linear-mode avalanche photodiodes (APDs) in high-speed CMOS imaging as compared to different approaches present in literature. Analysis of APDs biased below their breakdown voltage employed in single-photon counting mode is also discussed, showing a potentially interesting alternative to existing Geiger-mode APDs. An overview of the recently presented gated pinned avalanche photodiode pixel concept is provided, as well as the first experimental results on a 8 × 16 pixel test array. Full feasibility of the proposed pixel concept is not demonstrated; however, informative data is obtained from the sensor operating under -32 V substrate bias and clearly exhibiting wavelength-dependent gain in frontside illumination. The readout of the chip designed in standard 130 nm CMOS technology shows no dependence on the high-voltage bias. Readout noise level of 15 e - rms, full well capacity of 8000 e - , and the conversion gain of 75 µV / e - are extracted from the photon-transfer measurements. The gain characteristics of the avalanche junction are characterized on separate test diodes showing a multiplication factor of 1.6 for red light in frontside illumination. PMID:27537882

  8. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  9. Selecting Pixels for Kepler Downlink

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  10. Method for hyperspectral imagery exploitation and pixel spectral unmixing

    NASA Technical Reports Server (NTRS)

    Lin, Ching-Fang (Inventor)

    2003-01-01

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

  11. Single photon counting pixel detectors for synchrotron radiation experiments

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  12. Spectrally tunable pixel sensors

    NASA Astrophysics Data System (ADS)

    Langfelder, G.; Buffa, C.; Longoni, A. F.; Zaraga, F.

    2013-01-01

    They are here reported the developments and experimental results of fully operating matrices of spectrally tunable pixels based on the Transverse Field Detector (TFD). Unlike several digital imaging sensors based on color filter arrays or layered junctions, the TFD has the peculiar feature of having electrically tunable spectral sensitivities. In this way the sensor color space is not fixed a priori but can be real-time adjusted, e.g. for a better adaptation to the scene content or for multispectral capture. These advantages come at the cost of an increased complexity both for the photosensitive elements and for the readout electronics. The challenges in the realization of a matrix of TFD pixels are analyzed in this work. First experimental results on an 8x8 (x 3 colors) and on a 64x64 (x 3 colors) matrix will be presented and analyzed in terms of colorimetric and noise performance, and compared to simulation predictions.

  13. Digital-pixel focal plane array development

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

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

  14. The ALICE Pixel Detector

    NASA Astrophysics Data System (ADS)

    Mercado-Perez, Jorge

    2002-07-01

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

  15. Imaging properties of pixellated scintillators with deep pixels

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  16. Imaging properties of pixellated scintillators with deep pixels

    PubMed Central

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

    2015-01-01

    We have investigated the light-transport properties of scintillator arrays with long, thin pixels (deep pixels) for use in high-energy gamma-ray imaging. We compared 10×10 pixel arrays of YSO:Ce, LYSO:Ce and BGO (1mm × 1mm × 20 mm pixels) made by Proteus, Inc. with similar 10×10 arrays of LSO:Ce and BGO (1mm × 1mm × 15mm pixels) loaned to us by Saint-Gobain. The imaging and spectroscopic behaviors of these scintillator arrays are strongly affected by the choice of a reflector used as an inter-pixel spacer (3M ESR in the case of the Proteus arrays and white, diffuse-reflector for the Saint-Gobain arrays). We have constructed a 3700-pixel LYSO:Ce Prototype NIF Gamma-Ray Imager for use in diagnosing target compression in inertial confinement fusion. This system was tested at the OMEGA Laser and exhibited significant optical, inter-pixel cross-talk that was traced to the use of a single-layer of ESR film as an inter-pixel spacer. We show how the optical cross-talk can be mapped, and discuss correction procedures. We demonstrate a 10×10 YSO:Ce array as part of an iQID (formerly BazookaSPECT) imager and discuss issues related to the internal activity of 176Lu in LSO:Ce and LYSO:Ce detectors. PMID:26236070

  17. Design of ADC in 25 μm pixels pitch dedicated for IRFPA image processing at LETI

    NASA Astrophysics Data System (ADS)

    Tchagaspanian, M.; Villard, P.; Dupont, B.; Chammings, G.; Martin, J. L.; Pistre, C.; Lattard, D.; Chantre, C.; Arnaud, A.; Yon, J. J.; Simoens, F.; Tissot, J. L.

    2007-04-01

    LETI has been involved in IRFPA development since 1978, the design department (LETI/DCIS) has focused its work on new ROIC architecture since many years. The trend is to integrate advanced functions into the CMOS design in the aim of making cost efficient sensors. The purpose of this paper is to present the latest developments of an Analog to Digital Converter embedded in a 25μm pixel. The design is driven by several goals. It targets both long integration time and snapshot exposure, 100% of image frame time being available for integration. All pixels are integrating the IR signal at the same time. The IR signal is converted into digital by using a charge packet counter. High density 130nm CMOS allows to use many digital functions such as counting, memory and addressing. This new structure has been applied to 25μm pitch bolometer sensors with a dedicated 320 x 240 IRCMOS circuit. Due to smart image processing in the CMOS, the bolometer architecture requirements may become very simple and low cost. The room temperature sensitivity and the DC offset are solved directly in the pixel. This FPA targets low NETD (<50mK), a variation of 80 Kelvin for the FPA temperature, 14 bits output at 50/60Hz video rate.

  18. Prototypes for components of a control system for the ATLAS pixel detector at the HL-LHC

    NASA Astrophysics Data System (ADS)

    Püllen, Lukas; Boek, Jennifer; Kersten, Susanne; Kind, Peter; Mättig, Peter; Zeitnitz, Christian

    2013-12-01

    In the years around 2020 an upgrade of the LHC to the HL-LHC is scheduled, which will increase the accelerator's instantaneous luminosity by a factor of 5 and the integrated luminosity by a factor of 10. In the context of this upgrade, the inner detector (including the pixel detector) of the ATLAS experiment will be replaced. This new pixel detector requires a specific control system which complies with strict requirements in terms of radiation hardness, material budget and space for the electronics in the ATLAS experiment. The University of Wuppertal is developing a concept for a DCS (Detector Control System) network consisting of two kinds of ASICs. The first ASIC is the DCS chip which is located on the pixel detector, very close to the interaction point. The second ASIC is the DCS Controller which is controlling 4×4 DCS chips from the outer regions of ATLAS via differential data lines. Both ASICs are manufactured in 130 nm deep sub-micron technology. We present results from reliability measurements under irradiation from new prototypes of components for the DCS network.

  19. Prototypes for components of a control system for the ATLAS pixel detector at the HL-LHC

    NASA Astrophysics Data System (ADS)

    Boek, J.; Kersten, S.; Kind, P.; Mättig, P.; Püllen, L.; Zeitnitz, C.

    2013-03-01

    In the years around 2020 an upgrade of the LHC to the HL-LHC is scheduled, which will increase the accelerators luminosity by a factor of 10. In the context of this upgrade, the inner detector of the ATLAS experiment will be replaced entirely including the pixel detector. This new pixel detector requires a specific control system which complies with the strict requirements in terms of radiation hardness, material budget and space for the electronics in the ATLAS experiment. The University of Wuppertal is developing a concept for a DCS (Detector Control System) network consisting of two kinds of ASICs. The first ASIC is the DCS Chip which is located on the pixel detector, very close to the interaction point. The second ASIC is the DCS Controller which is controlling 4x4 DCS Chips from the outer regions of ATLAS via differential data lines. Both ASICs are manufactured in 130 nm deep sub micron technology. We present results from measurements from new prototypes of components for the DCS network.

  20. Pixelation Effects in Weak Lensing

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  1. Pixelation Effects in Weak Lensing

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

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

  2. THE KEPLER PIXEL RESPONSE FUNCTION

    SciTech Connect

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

    2010-04-20

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

  3. Characterization of the energy resolution and the tracking capabilities of a hybrid pixel detector with CdTe-sensor layer for a possible use in a neutrinoless double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Filipenko, Mykhaylo; Gleixner, Thomas; Anton, Gisela; Durst, Jürgen; Michel, Thilo

    2013-04-01

    Many different experiments are being developed to explore the existence of the neutrinoless double beta decay (0 νββ) since it would imply fundamental consequences for particle physics. In this work we present results on the evaluation of Timepix detectors with cadmium-telluride sensor material to search for 0 νββ in 116Cd. This work was carried out with the COBRA collaboration and the Medipix collaboration. Due to the relatively small pixel dimension of 110×110×1000 μm3 the energy deposited by particles typically extends over several detector pixels leading to a track in the pixel matrix. We investigated the separation power regarding different event-types like α-particles, atmospheric muons, single electrons and electron-positron pairs produced at a single vertex. We achieved excellent classification power for α-particles and muons. In addition, we achieved good separation power between single electron and electron-positron pair production events. These separation abilities indicate a very good background reduction for the 0 νββ search. Further, in order to distinguish between 2 νββ and 0 νββ, the energy resolution is of particular importance. We carried out simulations which demonstrate that an energy resolution of 0.43 % is achievable at the Q-value for 0 νββ of 116Cd at 2.814 MeV. We measured an energy resolution of 1.6 % at a nominal energy of 1589 keV for electron-positron tracks which is about two times worse that predicted by our simulations. This deviation is probably due to the problem of detector calibration at energies above 122 keV which is discussed in this paper as well.

  4. Rework of flip chip bonded radiation pixel detectors

    NASA Astrophysics Data System (ADS)

    Vähänen, S.; Heikkinen, H.; Pohjonen, H.; Salonen, J.; Savolainen-Pulli, S.

    2008-06-01

    In this paper, some practical aspects of reworking flip chip hybridized pixel detectors are discussed. As flip chip technology has been advancing in terms of placement accuracy and reliability, large-area hybrid pixel detectors have been developed. The area requirements are usually fulfilled by placing several readout chips (ROCs) on single sensor chip. However, as the number of ROCs increases, the probability of failure in the hybridization process and the ROC operation also increases. Because high accuracy flip chip bonding takes time, a significant part of the price of a pixel detector comes from the flip chip assembly process itself. As large-area detector substrates are expensive, and many flip chip placements are required, the price of an assembled detector can become very high. In a typical case, there is just one bad ROC (out of several) on a faulty detector to be replaced. Considering the high price of pixel detectors and the fact that reworking faulty ROCs does not take much longer than the original placement, it is worthwhile to investigate the feasibility of a rework process.

  5. From Pixels to Planets

    NASA Technical Reports Server (NTRS)

    Brownston, Lee; Jenkins, Jon M.

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

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

    PubMed

    Rogalski, A; Martyniuk, P; Kopytko, M

    2016-04-01

    In the last two decades, several new concepts for improving the performance of infrared detectors have been proposed. These new concepts particularly address the drive towards the so-called high operating temperature focal plane arrays (FPAs), aiming to increase detector operating temperatures, and as a consequence reduce the cost of infrared systems. In imaging systems with the above megapixel formats, pixel dimension plays a crucial role in determining critical system attributes such as system size, weight and power consumption (SWaP). The advent of smaller pixels has also resulted in the superior spatial and temperature resolution of these systems. Optimum pixel dimensions are limited by diffraction effects from the aperture, and are in turn wavelength-dependent. In this paper, the key challenges in realizing optimum pixel dimensions in FPA design including dark current, pixel hybridization, pixel delineation, and unit cell readout capacity are outlined to achieve a sufficiently adequate modulation transfer function for the ultra-small pitches involved. Both photon and thermal detectors have been considered. Concerning infrared photon detectors, the trade-offs between two types of competing technology-HgCdTe material systems and III-V materials (mainly barrier detectors)-have been investigated. PMID:27007242

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

    NASA Astrophysics Data System (ADS)

    Anderson, Jay

    2014-12-01

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

  9. Depleted CMOS pixels for LHC proton-proton experiments

    NASA Astrophysics Data System (ADS)

    Wermes, N.

    2016-07-01

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

  10. A Medium-Format, Mixed-Mode Pixel Array Detector for Kilohertz X-ray Imaging

    NASA Astrophysics Data System (ADS)

    Tate, M. W.; Chamberlain, D.; Green, K. S.; Philipp, H. T.; Purohit, P.; Strohman, C.; Gruner, S. M.

    2013-03-01

    An x-ray pixel array detector (PAD) capable of framing up to 1 kHz is described. This hybrid detector is constructed from a 3-side buttable, 128×128 pixel module based upon the mixed-mode pixel array detector (MMPAD) chip developed jointly by Cornell and Area Detector Systems Corporation (Poway, CA). The chip uses a charge integrating front end for a high instantaneous count rate yet with single photon sensitivity. In-pixel circuitry utilizing a digital overflow counter extends the per frame dynamic range to >4×107 x-rays/pixel. Results are shown from a base configuration of a 2×3 module array (256×384 pixels).

  11. The LAMBDA photon-counting pixel detector

    NASA Astrophysics Data System (ADS)

    Pennicard, D.; Lange, S.; Smoljanin, S.; Hirsemann, H.; Graafsma, H.; Epple, M.; Zuvic, M.; Lampert, M.-O.; Fritzsch, T.; Rothermund, M.

    2013-03-01

    The Medipix3 photon-counting detector chip has a number of novel features that are attractive for synchrotron experiments, such as a high frame rate with zero dead time and high spatial resolution. DESY are developing a large-area Medipix3-based detector array (LAMBDA). A single LAMBDA module consists of 2 by 6 Medipix3 chips on a ceramic carrier board, bonded to either a single large silicon sensor or two smaller high-Z sensors. The readout system fits behind the carrier board to allow module tiling, and uses a large on-board RAM and multiple 10 Gigabit Ethernet links to permit high-speed readout. Currently, the first large silicon modules have been constructed and read out at low speed, and the firmware for highspeed readout is being developed. In addition to these silicon sensors, we are developing a germanium hybrid pixel detector in collaboration with Canberra for higher-energy beamlines. Canberra have produced a set of 256-by-256-pixel planar germanium sensors with 55μm pitch, and these are currently being bonded to Medipix3 readout chips by Fraunhofer IZM (Berlin).

  12. Dual-gate photo thin-film transistor: a “smart” pixel for high- resolution and low-dose X-ray imaging

    NASA Astrophysics Data System (ADS)

    Wang, Kai; Ou, Hai; Chen, Jun

    2015-06-01

    Since its emergence a decade ago, amorphous silicon flat panel X-ray detector has established itself as a ubiquitous platform for an array of digital radiography modalities. The fundamental building block of a flat panel detector is called a pixel. In all current pixel architectures, sensing, storage, and readout are unanimously kept separate, inevitably compromising resolution by increasing pixel size. To address this issue, we hereby propose a “smart” pixel architecture where the aforementioned three components are combined in a single dual-gate photo thin-film transistor (TFT). In other words, the dual-gate photo TFT itself functions as a sensor, a storage capacitor, and a switch concurrently. Additionally, by harnessing the amplification effect of such a thin-film transistor, we for the first time created a single-transistor active pixel sensor. The proof-of-concept device had a W/L ratio of 250μm/20μm and was fabricated using a simple five-mask photolithography process, where a 130nm transparent ITO was used as the top photo gate, and a 200nm amorphous silicon as the absorbing channel layer. The preliminary results demonstrated that the photocurrent had been increased by four orders of magnitude due to light-induced threshold voltage shift in the sub-threshold region. The device sensitivity could be simply tuned by photo gate bias to specifically target low-level light detection. The dependence of threshold voltage on light illumination indicated that a dynamic range of at least 80dB could be achieved. The "smart" pixel technology holds tremendous promise for developing high-resolution and low-dose X-ray imaging and may potentially lower the cancer risk imposed by radiation, especially among paediatric patients.

  13. Front-end intelligence for triggering and local track measurement in gaseous pixel detectors

    NASA Astrophysics Data System (ADS)

    Gromov, V.; Hessey, N.; Vermeulen, J.

    2012-11-01

    A number of applications in high-energy physics and medicine requires three-dimensional reconstruction of the particle trajectories: for example, high momentum particles in accelerator-based experiments can be identified on the basis of the properties of their tracks, while in proton computed tomography accurate knowledge of the incoming and outgoing beam trajectory is crucial in reconstructing the most probable path of the proton traversing the patient. In this work we investigate the potential of Gaseous Pixel (GridPix) detectors for fast and efficient recognition of tracks and determination of their properties. This includes selection, without external trigger, of tracks with desired angles, for example tracks with small tilt angles corresponding to high momentum particles in a magnetic field. Being able to select these fast and without external input is of interest for the future upgrades of the LHC detectors. In this paper we present a track selection algorithm, and its physical implementation in 130 nm CMOS technology with estimates of power consumption, data rates, latency, and chip area. The Timepix3 chip, currently being designed for a wide range of applications, will also be suitable for readout of GridPix detectors. Both arrival time information (accuracy 1.6 ns) and charge deposit information will be delivered for each hit together with the coordinates of the active pixel. A short overview is presented of its architecture, which allows continuous self-triggered readout of sparsely distributed data with a rate up to 20 × 106 hits cm-2sec-1. The addition of fast track pattern recognition logic to TimePix3 in a successor chip is currently being investigated.

  14. The CMS pixel luminosity telescope

    NASA Astrophysics Data System (ADS)

    Kornmayer, A.

    2016-07-01

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

  15. Microradiography with Semiconductor Pixel Detectors

    NASA Astrophysics Data System (ADS)

    Jakubek, Jan; Cejnarova, Andrea; Dammer, Jiří; Holý, Tomáš; Platkevič, Michal; Pospíšil, Stanislav; Vavřík, Daniel; Vykydal, Zdeněk

    2007-11-01

    High resolution radiography (with X-rays, neutrons, heavy charged particles, …) often exploited also in tomographic mode to provide 3D images stands as a powerful imaging technique for instant and nondestructive visualization of fine internal structure of objects. Novel types of semiconductor single particle counting pixel detectors offer many advantages for radiation imaging: high detection efficiency, energy discrimination or direct energy measurement, noiseless digital integration (counting), high frame rate and virtually unlimited dynamic range. This article shows the application and potential of pixel detectors (such as Medipix2 or TimePix) in different fields of radiation imaging.

  16. Electrical characterization of irradiated prototype silicon pixel sensors for BTeV

    SciTech Connect

    Maria Rita Coluccia et al.

    2002-11-13

    The pixel detector in the BteV experiment at the Tevatron (Fermi Laboratory) is an important detector component for high-resolution tracking and vertex identification. For this task the hybrid pixel detector has to work in a very harsh radiation environment with up to 10{sup 14} minimum ionizing particles/cm{sup 2}/year. Radiation hardness of prototype n{sup +}/n/p{sup +} silicon pixel sensors has been investigated. We present Electrical characterization curves for irradiated prototype n{sup +}/n/p{sup +} sensors, intended for use in the BTeV experiment. We tested pixel sensors from various vendors and with two pixel isolation techniques: p-stop and p-spray. Results are based on irradiation with 200 MeV protons up to 6 x 10{sup 14} protons/cm{sup 2}.

  17. SAR Image Complex Pixel Representations

    SciTech Connect

    Doerry, Armin W.

    2015-03-01

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

  18. Representing SAR complex image pixels

    NASA Astrophysics Data System (ADS)

    Doerry, A. W.

    2016-05-01

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

  19. CMOS digital pixel sensors: technology and applications

    NASA Astrophysics Data System (ADS)

    Skorka, Orit; Joseph, Dileepan

    2014-04-01

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

  20. Low complexity pixel-based halftone detection

    NASA Astrophysics Data System (ADS)

    Ok, Jiheon; Han, Seong Wook; Jarno, Mielikainen; Lee, Chulhee

    2011-10-01

    With the rapid advances of the internet and other multimedia technologies, the digital document market has been growing steadily. Since most digital images use halftone technologies, quality degradation occurs when one tries to scan and reprint them. Therefore, it is necessary to extract the halftone areas to produce high quality printing. In this paper, we propose a low complexity pixel-based halftone detection algorithm. For each pixel, we considered a surrounding block. If the block contained any flat background regions, text, thin lines, or continuous or non-homogeneous regions, the pixel was classified as a non-halftone pixel. After excluding those non-halftone pixels, the remaining pixels were considered to be halftone pixels. Finally, documents were classified as pictures or photo documents by calculating the halftone pixel ratio. The proposed algorithm proved to be memory-efficient and required low computation costs. The proposed algorithm was easily implemented using GPU.

  1. The FPGA Pixel Array Detector

    NASA Astrophysics Data System (ADS)

    Hromalik, Marianne S.; Green, Katherine S.; Philipp, Hugh T.; Tate, Mark W.; Gruner, Sol M.

    2013-02-01

    A proposed design for a reconfigurable x-ray Pixel Array Detector (PAD) is described. It operates by integrating a high-end commercial field programmable gate array (FPGA) into a 3-layer device along with a high-resistivity diode detection layer and a custom, application-specific integrated circuit (ASIC) layer. The ASIC layer contains an energy-discriminating photon-counting front end with photon hits streamed directly to the FPGA via a massively parallel, high-speed data connection. FPGA resources can be allocated to perform user defined tasks on the pixel data streams, including the implementation of a direct time autocorrelation function (ACF) with time resolution down to 100 ns. Using the FPGA at the front end to calculate the ACF reduces the required data transfer rate by several orders of magnitude when compared to a fast framing detector. The FPGA-ASIC high-speed interface, as well as the in-FPGA implementation of a real-time ACF for x-ray photon correlation spectroscopy experiments has been designed and simulated. A 16×16 pixel prototype of the ASIC has been fabricated and is being tested.

  2. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  3. Making a trillion pixels dance

    NASA Astrophysics Data System (ADS)

    Singh, Vivek; Hu, Bin; Toh, Kenny; Bollepalli, Srinivas; Wagner, Stephan; Borodovsky, Yan

    2008-03-01

    In June 2007, Intel announced a new pixelated mask technology. This technology was created to address the problem caused by the growing gap between the lithography wavelength and the feature sizes patterned with it. As this gap has increased, the quality of the image has deteriorated. About a decade ago, Optical Proximity Correction (OPC) was introduced to bridge this gap, but as this gap continued to increase, one could not rely on the same basic set of techniques to maintain image quality. The computational lithography group at Intel sought to alleviate this problem by experimenting with additional degrees of freedom within the mask. This paper describes the resulting pixelated mask technology, and some of the computational methods used to create it. The first key element of this technology is a thick mask model. We realized very early in the development that, unlike traditional OPC methods, the pixelated mask would require a very accurate thick mask model. Whereas in the traditional methods, one can use the relatively coarse approximations such as the boundary layer method, use of such techniques resulted not just in incorrect sizing of parts of the pattern, but in whole features missing. We built on top of previously published domain decomposition methods, and incorporated limitations of the mask manufacturing process, to create an accurate thick mask model. Several additional computational techniques were invoked to substantially increase the speed of this method to a point that it was feasible for full chip tapeout. A second key element of the computational scheme was the comprehension of mask manufacturability, including the vital issue of the number of colors in the mask. While it is obvious that use of three or more colors will give the best image, one has to be practical about projecting mask manufacturing capabilities for such a complex mask. To circumvent this serious issue, we eventually settled on a two color mask - comprising plain glass and etched

  4. Pixelated filters for spatial imaging

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  5. Predicting human gaze beyond pixels.

    PubMed

    Xu, Juan; Jiang, Ming; Wang, Shuo; Kankanhalli, Mohan S; Zhao, Qi

    2014-01-01

    A large body of previous models to predict where people look in natural scenes focused on pixel-level image attributes. To bridge the semantic gap between the predictive power of computational saliency models and human behavior, we propose a new saliency architecture that incorporates information at three layers: pixel-level image attributes, object-level attributes, and semantic-level attributes. Object- and semantic-level information is frequently ignored, or only a few sample object categories are discussed where scaling to a large number of object categories is not feasible nor neurally plausible. To address this problem, this work constructs a principled vocabulary of basic attributes to describe object- and semantic-level information thus not restricting to a limited number of object categories. We build a new dataset of 700 images with eye-tracking data of 15 viewers and annotation data of 5,551 segmented objects with fine contours and 12 semantic attributes (publicly available with the paper). Experimental results demonstrate the importance of the object- and semantic-level information in the prediction of visual attention. PMID:24474825

  6. Position-Sensitive Nuclear Spectroscopy with Pixel Detectors

    SciTech Connect

    Granja, Carlos; Vykydal, Zdenek; Jakubek, Jan; Pospisil, Stanislav

    2007-10-26

    State-of-the-art hybrid semiconductor pixel detectors such as Medipix2 are suitable for energy- and position-sensitive nuclear spectroscopy. In addition to excellent energy- and spatial-resolution, these devices can operate in spectroscopic, single-quantum counting and/or on-line tracking mode. A devoted compact USB-readout interface provides functionality and ease of operation. The compact and versatile Medipix2/USB radiation camera provides visualization, vacuum and room-temperature operation as a real-time portable active nuclear emulsion.

  7. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  8. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  9. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  10. Proceedings of PIXEL98 -- International pixel detector workshop

    SciTech Connect

    Anderson, D.F.; Kwan, S.

    1998-08-01

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

  11. Fast Imaging Detector Readout Circuits with In-Pixel ADCs for Fourier Transform Imaging Spectrometers

    NASA Technical Reports Server (NTRS)

    Rider, D.; Blavier, J-F.; Cunningham, T.; Hancock, B.; Key, R.; Pannell, Z.; Sander, S.; Seshadri, S.; Sun, C.; Wrigley, C.

    2011-01-01

    Focal plane arrays (FPAs) with high frame rates and many pixels benefit several upcoming Earth science missions including GEO-CAPE, GACM, and ACE by enabling broader spatial coverage and higher spectral resolution. FPAs for the PanFTS, a high spatial resolution Fourier transform spectrometer and a candidate instrument for the GEO-CAPE mission are the focus of the developments reported here, but this FPA technology has the potential to enable a variety of future measurements and instruments. The ESTO ACT Program funded the developed of a fast readout integrated circuit (ROIC) based on an innovative in-pixel analog-to-digital converter (ADC). The 128 X 128 pixel ROIC features 60 ?m pixels, a 14-bit ADC in each pixel and operates at a continuous frame rate of 14 kHz consuming only 1.1 W of power. The ROIC outputs digitized data completely eliminating the bulky, power consuming signal chains needed by conventional FPAs. The 128 X 128 pixel ROIC has been fabricated in CMOS and tested at the Jet Propulsion Laboratory. The current version is designed to be hybridized with PIN photodiode arrays via indium bump bonding for light detection in the visible and ultraviolet spectral regions. However, the ROIC design incorporates a small photodiode in each cell to permit detailed characterization of the ROICperformance without the need for hybridization. We will describe the essential features of the ROIC design and present results of ROIC performance measurements.

  12. Serial Pixel Analog-to-Digital Converter

    SciTech Connect

    Larson, E D

    2010-02-01

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

  13. Design of the low area monotonic trim DAC in 40 nm CMOS technology for pixel readout chips

    NASA Astrophysics Data System (ADS)

    Drozd, A.; Szczygiel, R.; Maj, P.; Satlawa, T.; Grybos, P.

    2014-12-01

    The recent research in hybrid pixel detectors working in single photon counting mode focuses on nanometer or 3D technologies which allow making pixels smaller and implementing more complex solutions in each of the pixels. Usually single pixel in readout electronics for X-ray detection comprises of charge amplifier, shaper and discriminator that allow classification of events occurring at the detector as true or false hits by comparing amplitude of the signal obtained with threshold voltage, which minimizes the influence of noise effects. However, making the pixel size smaller often causes problems with pixel to pixel uniformity and additional effects like charge sharing become more visible. To improve channel-to-channel uniformity or implement an algorithm for charge sharing effect minimization, small area trimming DACs working in each pixel independently are necessary. However, meeting the requirement of small area often results in poor linearity and even non-monotonicity. In this paper we present a novel low-area thermometer coded 6-bit DAC implemented in 40 nm CMOS technology. Monte Carlo simulations were performed on the described design proving that under all conditions designed DAC is inherently monotonic. Presented DAC was implemented in the prototype readout chip with 432 pixels working in single photon counting mode, with two trimming DACs in each pixel. Each DAC occupies the area of 8 μm × 18.5 μm. Measurements and chips' tests were performed to obtain reliable statistical results.

  14. High dynamic range pixel architecture for advanced diagnostic medical x-ray imaging applications

    SciTech Connect

    Izadi, Mohammad Hadi; Karim, Karim S.

    2006-05-15

    The most widely used architecture in large-area amorphous silicon (a-Si) flat panel imagers is a passive pixel sensor (PPS), which consists of a detector and a readout switch. While the PPS has the advantage of being compact and amenable toward high-resolution imaging, small PPS output signals are swamped by external column charge amplifier and data line thermal noise, which reduce the minimum readable sensor input signal. In contrast to PPS circuits, on-pixel amplifiers in a-Si technology reduce readout noise to levels that can meet even the stringent requirements for low noise digital x-ray fluoroscopy (<1000 noise electrons). However, larger voltages at the pixel input cause the output of the amplified pixel to become nonlinear thus reducing the dynamic range. We reported a hybrid amplified pixel architecture based on a combination of PPS and amplified pixel designs that, in addition to low noise performance, also resulted in large-signal linearity and consequently higher dynamic range [K. S. Karim et al., Proc. SPIE 5368, 657 (2004)]. The additional benefit in large-signal linearity, however, came at the cost of an additional pixel transistor. We present an amplified pixel design that achieves the goals of low noise performance and large-signal linearity without the need for an additional pixel transistor. Theoretical calculations and simulation results for noise indicate the applicability of the amplified a-Si pixel architecture for high dynamic range, medical x-ray imaging applications that require switching between low exposure, real-time fluoroscopy and high-exposure radiography.

  15. Dead pixel replacement in LWIR microgrid polarimeters.

    PubMed

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

    2007-06-11

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

  16. Dead pixel replacement in LWIR microgrid polarimeters

    NASA Astrophysics Data System (ADS)

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

    2007-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  18. Infrared astronomy - Pixels to spare

    SciTech Connect

    Mccaughrean, M. )

    1991-07-01

    An infrared CCD camera containing an array with 311,040 pixels arranged in 486 rows of 640 each is tested. The array is a chip of platinum silicide (PtSi), sensitive to photons with wavelengths between 1 and 6 microns. Observations of the Hubble Space Telescope, Mars, Pluto and moon are reported. It is noted that the satellite's twin solar-cell arrays, at an apparent separation of about 1 1/4 arc second, are well resolved. Some two dozen video frames were stacked to make each presented image of Mars at 1.6 microns; at this wavelength Mars appears much as it does in visible light. A stack of 11 images at a wavelength of 1.6 microns is used for an image of Jupiter with its Great Red Spot and moons Io and Europa.

  19. Method for fabricating pixelated silicon device cells

    SciTech Connect

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

    2015-08-18

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

  20. Commissioning of the CMS Forward Pixel Detector

    SciTech Connect

    Kumar, Ashish; /SUNY, Buffalo

    2008-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  2. High throughput optoelectronic smart pixel systems using diffractive optics

    NASA Astrophysics Data System (ADS)

    Chen, Chih-Hao

    1999-12-01

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

  3. Hot pixel generation in active pixel sensors: dosimetric and micro-dosimetric response

    NASA Technical Reports Server (NTRS)

    Scheick, Leif; Novak, Frank

    2003-01-01

    The dosimetric response of an active pixel sensor is analyzed. heavy ions are seen to damage the pixel in much the same way as gamma radiation. The probability of a hot pixel is seen to exhibit behavior that is not typical with other microdose effects.

  4. High-MTF hybrid ferroelectric IRFPA

    NASA Astrophysics Data System (ADS)

    Evans, Scott B.; Hayden, Terrence

    1998-07-01

    Low cost, uncooled hybrid infrared focal plane arrays (IRFPA's) are in full-scale production at Raytheon Systems Company (RSC), formerly Texas Instruments Defense Systems and Electronics Group. Detectors consist of reticulated ceramic barium strontium titanate (BST) arrays of 320 X 240 pixels on 48.5 micrometer pitch. The principal performance shortcoming of the hybrid arrays has been low MTF due to thermal crosstalk between pixels. In the past two years, significant improvements have been made to increase MTF making hybrids more competitive in performance with monolithic arrays. The improvements are (1) the reduction of the thickness of the IR absorbing layer electrode that maintains electrical continuity and increases thermal isolation between pixels, (2) reduction of the electrical crosstalk from the ROIC, and (3) development of a process to increase the thermal path-length between pixels called 'elevated optical coat.' This paper describes all three activities and their efficacy. Also discussed is the uncooled IRFPA production capability at RSC.

  5. Soil moisture variability within remote sensing pixels

    NASA Astrophysics Data System (ADS)

    Charpentier, Michael A.; Groffman, Peter M.

    1992-11-01

    The effects of topography and the level of soil moisture on the variability of soil moisture within remote sensing pixels were assessed during the First ISLSCP Field Experiment (FIFE) during 1987 and 1989. Soil moisture data from flat, sloped, and valley-shaped pixels were obtained over a wide range of moisture conditions. Relative elevation data were obtained for each study area to create digital elevation models with which to quantify topographic variability. Within-pixel soil moisture variability was shown to increase with increased topographic heterogeneity. The flat pixel had significantly lower standard deviations and fewer outlier points than the slope and valley pixels. Most pixel means had a positive skewness, indicating that most pixels will have areas of markedly higher than average soil moisture. Soil moisture variability (as indicated by the coefficient of variation) decreased as soil moisture levels increased. However, the absolute value of the standard deviation of soil moisture was independent of wetness. The data suggest that remote sensing will reflect soil moisture conditions less accurately on pixels with increased topographic variability and less precisely when the soil is dry. These differences in the inherent accuracy and precision of remote sensing soil moisture data should be considered when evaluating error sources in analyses of energy balance or biogeochemical processes that utilize soil moisture data produced by remote sensing.

  6. High stroke pixel for a deformable mirror

    DOEpatents

    Miles, Robin R.; Papavasiliou, Alexandros P.

    2005-09-20

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

  7. Demonstration of 1024x1024 pixel dual-band QWIP focal plane array

    NASA Astrophysics Data System (ADS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Mumolo, J. M.; Ting, D. Z.; Hill, C. J.; Nguyen, J.; Rafol, S. B.

    2010-04-01

    QWIPs are well known for their stability, high pixel-pixel uniformity and high pixel operability which are quintessential parameters for large area imaging arrays. In this paper we report the first demonstration of the megapixel-simultaneously-readable and pixel-co-registered dual-band QWIP focal plane array (FPA). The dual-band QWIP device was developed by stacking two multi-quantum-well stacks tuned to absorb two different infrared wavelengths. The full width at half maximum (FWHM) of the mid-wave infrared (MWIR) band extends from 4.4 - 5.1 μm and FWHM of the long-wave infrared (LWIR) band extends from 7.8 - 8.8 μm. Dual-band QWIP detector arrays were hybridized with direct injection 30 μm pixel pitch megapixel dual-band simultaneously readable CMOS read out integrated circuits using the indium bump hybridization technique. The initial dual-band megapixel QWIP FPAs were cooled to 68K operating temperature. The preliminary data taken from the first megapixel QWIP FPA has shown system NE▵T of 27 and 40 mK for MWIR and LWIR bands respectively.

  8. Planar Microfluidic System Based on Electrophoresis for Detection of 130-nm Magnetic Labels for Biosensing

    NASA Astrophysics Data System (ADS)

    Takamura, Tsukasa; Morimoto, Yoshitaka; Sandhu, Adarsh

    2011-04-01

    Superparamagnetic beads (SPBs) used as magnetic labels offer potential for the realization of high sensitivity and low cost biosensors for point of care treatment (POCT). For better biomolecular affinity and higher sensitivity, it is desirable to use sub-200-nm-diameter SPBs comparable in size to actual biomolecules. However, the detection of small concentrations of such SPBs by magnetoresistive devices is extremely challenging due to small magnetic response of SPBs. As a solution to these limitations, we describe a simple detecting procedure where the capture of micro-SPBs by immobilized nano-target SPBs due to self-assembly induced by an external magnetic field, which was monitored under an optical microscope. Here we describe biosensing system based on self-assembly of micro-SPBs by nanoSPBs targets using a system without external pumps, thereby enabling greater miniaturization and portability.

  9. Impact of Spacecraft Shielding on Direct Ionization Soft Error Rates for sub-130 nm Technologies

    NASA Technical Reports Server (NTRS)

    Pellish, Jonathan A.; Xapsos, Michael A.; Stauffer, Craig A.; Jordan, Michael M.; Sanders, Anthony B.; Ladbury, Raymond L.; Oldham, Timothy R.; Marshall, Paul W.; Heidel, David F.; Rodbell, Kenneth P.

    2010-01-01

    We use ray tracing software to model various levels of spacecraft shielding complexity and energy deposition pulse height analysis to study how it affects the direct ionization soft error rate of microelectronic components in space. The analysis incorporates the galactic cosmic ray background, trapped proton, and solar heavy ion environments as well as the October 1989 and July 2000 solar particle events.

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

    NASA Astrophysics Data System (ADS)

    Niroumand-Jadidi, Milad; Vitti, Alfonso

    2015-10-01

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

  11. Pixel multichip module development at Fermilab

    SciTech Connect

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

    2005-10-01

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

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

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    2012-01-01

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

  13. The Dosepix detector—an energy-resolving photon-counting pixel detector for spectrometric measurements

    NASA Astrophysics Data System (ADS)

    Zang, A.; Anton, G.; Ballabriga, R.; Bisello, F.; Campbell, M.; Celi, J. C.; Fauler, A.; Fiederle, M.; Jensch, M.; Kochanski, N.; Llopart, X.; Michel, N.; Mollenhauer, U.; Ritter, I.; Tennert, F.; Wölfel, S.; Wong, W.; Michel, T.

    2015-04-01

    The Dosepix detector is a hybrid photon-counting pixel detector based on ideas of the Medipix and Timepix detector family. 1 mm thick cadmium telluride and 300 μm thick silicon were used as sensor material. The pixel matrix of the Dosepix consists of 16 x 16 square pixels with 12 rows of (200 μm)2 and 4 rows of (55 μm)2 sensitive area for the silicon sensor layer and 16 rows of pixels with 220 μm pixel pitch for CdTe. Besides digital energy integration and photon-counting mode, a novel concept of energy binning is included in the pixel electronics, allowing energy-resolved measurements in 16 energy bins within one acquisition. The possibilities of this detector concept range from applications in personal dosimetry and energy-resolved imaging to quality assurance of medical X-ray sources by analysis of the emitted photon spectrum. In this contribution the Dosepix detector, its response to X-rays as well as spectrum measurements with Si and CdTe sensor layer are presented. Furthermore, a first evaluation was carried out to use the Dosepix detector as a kVp-meter, that means to determine the applied acceleration voltage from measured X-ray tubes spectra.

  14. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation

    PubMed Central

    Philipp, Hugh T.; Tate, Mark W.; Purohit, Prafull; Shanks, Katherine S.; Weiss, Joel T.; Gruner, Sol M.

    2016-01-01

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8–12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10–100 ps) and intense X-ray pulses at megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. The characteristics, operation, testing and application of the detector are detailed. PMID:26917125

  15. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation.

    PubMed

    Philipp, Hugh T; Tate, Mark W; Purohit, Prafull; Shanks, Katherine S; Weiss, Joel T; Gruner, Sol M

    2016-03-01

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8-12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10-100 ps) and intense X-ray pulses at megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. The characteristics, operation, testing and application of the detector are detailed. PMID:26917125

  16. High Dynamic Range Pixel Array Detector for Scanning Transmission Electron Microscopy.

    PubMed

    Tate, Mark W; Purohit, Prafull; Chamberlain, Darol; Nguyen, Kayla X; Hovden, Robert; Chang, Celesta S; Deb, Pratiti; Turgut, Emrah; Heron, John T; Schlom, Darrell G; Ralph, Daniel C; Fuchs, Gregory D; Shanks, Katherine S; Philipp, Hugh T; Muller, David A; Gruner, Sol M

    2016-02-01

    We describe a hybrid pixel array detector (electron microscope pixel array detector, or EMPAD) adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy. The 128×128 pixel detector consists of a 500 µm thick silicon diode array bump-bonded pixel-by-pixel to an application-specific integrated circuit. The in-pixel circuitry provides a 1,000,000:1 dynamic range within a single frame, allowing the direct electron beam to be imaged while still maintaining single electron sensitivity. A 1.1 kHz framing rate enables rapid data collection and minimizes sample drift distortions while scanning. By capturing the entire unsaturated diffraction pattern in scanning mode, one can simultaneously capture bright field, dark field, and phase contrast information, as well as being able to analyze the full scattering distribution, allowing true center of mass imaging. The scattering is recorded on an absolute scale, so that information such as local sample thickness can be directly determined. This paper describes the detector architecture, data acquisition system, and preliminary results from experiments with 80-200 keV electron beams. PMID:26750260

  17. Per-Pixel Lighting Data Analysis

    SciTech Connect

    Inanici, Mehlika

    2005-08-01

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

  18. Low-noise reset technique of an asynchronous charge-pulse-detecting pixel for single-photon X-ray imaging

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Sik; Han, Kwan-Young

    2016-02-01

    This paper presents a low-noise reset technique of an asynchronous charge-pulse-detecting pixel for single-photon X-ray imaging. The proposed slow-slope ramp (S2R) reset scheme provides a reset-noise-discharging loop circuit and effectively eliminates the residual noise charge stored on the sampling capacitor by extending the falling transition time of the reset signal. In addition, the presented S2R reset signal generation circuit accurately and effectively controls the optimum switching voltage and the falling transition time of the reset signal. The prototype detector chip was implemented by using a 130-nm complementary metal-oxide semiconductor (CMOS) process. With the quantitative analysis and the measurement results, we were able to verify that the reset noise was reduced exponentially, corresponding to the falling transition time of the reset signal. Based on the chip measurement results, the reset-noise level could be decreased by more than seven-fold by virtue of the proposed reset technique.

  19. Pixels, Imagers and Related Fabrication Methods

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  20. Monolithic Active-Pixel Infrared Sensors

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    Monolithic arrays of active-pixel junction field-effect (JFET) devices made from InGaAs proposed for use as imaging sensors sensitive to light in visible and short-wavelength infrared parts of electromagnetic spectrum. Each pixel of such array comprises photodetector monolithically integrated with JFET output-amplifier circuit of source-follower type - structure similar to charge-coupled device (CCD). Sizes of instruments reduced because large cooling systems not needed.

  1. Design of the small pixel pitch ROIC

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  2. Steganography based on pixel intensity value decomposition

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  3. Small pixel oversampled IR focal plane arrays

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  4. 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.

  5. Study of silicon pixel sensor for synchrotron radiation detection

    NASA Astrophysics Data System (ADS)

    Li, Zhen-Jie; Jia, Yun-Cong; Hu, Ling-Fei; Liu, Peng; Yin, Hua-Xiang

    2016-03-01

    The silicon pixel sensor (SPS) is one of the key components of hybrid pixel single-photon-counting detectors for synchrotron radiation X-ray detection (SRD). In this paper, the design, fabrication, and characterization of SPSs for single beam X-ray photon detection is reported. The designed pixel sensor is a p+-in-n structure with guard-ring structures operated in full-depletion mode and is fabricated on 4-inch, N type, 320 μm thick, high-resistivity silicon wafers by a general Si planar process. To achieve high energy resolution of X-rays and obtain low dark current and high breakdown voltage as well as appropriate depletion voltage of the SPS, a series of technical optimizations of device structure and fabrication process are explored. With optimized device structure and fabrication process, excellent SPS characteristics with dark current of 2 nA/cm2, full depletion voltage < 50 V and breakdown voltage >150 V are achieved. The fabricated SPSs are wire bonded to ASIC circuits and tested for the performance of X-ray response to the 1W2B synchrotron beam line of the Beijing Synchrotron Radiation Facility. The measured S-curves for SRD demonstrate a high discrimination for different energy X-rays. The extracted energy resolution is high (<20% for X-ray photon energy >10 keV) and the linear properties between input photo energy and the equivalent generator amplitude are well established. It confirmed that the fabricated SPSs have a good energy linearity and high count rate with the optimized technologies. The technology is expected to have a promising application in the development of a large scale SRD system for the Beijing Advanced Photon Source. Supported by Prefabrication Research of Beijing Advanced Photon Source (R&D for BAPS) and National Natural Science Foundation of China (11335010)

  6. Multi-pixel high-resolution three-dimensional imaging radar

    NASA Technical Reports Server (NTRS)

    Cooper, Ken B. (Inventor); Dengler, Robert J. (Inventor); Siegel, Peter H. (Inventor); Chattopadhyay, Goutam (Inventor); Ward, John S. (Inventor); Juan, Nuria Llombart (Inventor); Bryllert, Tomas E. (Inventor); Mehdi, Imran (Inventor); Tarsala, Jan A. (Inventor)

    2012-01-01

    A three-dimensional imaging radar operating at high frequency e.g., 670 GHz radar using low phase-noise synthesizers and a fast chirper to generate a frequency-modulated continuous-wave (FMCW) waveform, is disclosed that operates with a multiplexed beam to obtain range information simultaneously on multiple pixels of a target. A source transmit beam may be divided by a hybrid coupler into multiple transmit beams multiplexed together and directed to be reflected off a target and return as a single receive beam which is demultiplexed and processed to reveal range information of separate pixels of the target associated with each transmit beam simultaneously. The multiple transmit beams may be developed with appropriate optics to be temporally and spatially differentiated before being directed to the target. Temporal differentiation corresponds to a different intermediate frequencies separating the range information of the multiple pixels. Collinear transmit beams having differentiated polarizations may also be implemented.

  7. Spatial clustering of pixels of a multispectral image

    DOEpatents

    Conger, James Lynn

    2014-08-19

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

  8. Depleted Monolithic Active Pixel Sensors (DMAPS) implemented in LF-150 nm CMOS technology

    NASA Astrophysics Data System (ADS)

    Kishishita, T.; Hemperek, T.; Krüger, H.; Wermes, N.

    2015-03-01

    We present the recent development of Depleted Monolithic Active Pixel Sensors (DMAPS), implemented with an LFoundry (LF) 150 nm CMOS process. MAPS detectors based on an epi-layer have been matured in recent years and have attractive features in terms of reducing material budget and handling cost compared to conventional hybrid pixel detectors. However, the obtained signal is relatively small (~1000 e-) due to the thin epi-layer, and charge collection time is relatively slow, e.g., in the order of 100 ns, because charges are mainly collected by diffusion. Modern commercial CMOS technology, however, offers advanced process options to overcome such difficulties and enable truly monolithic devices as an alternative to hybrid pixel sensors and charge coupled devices. Unlike in the case of the standard MAPS technologies with epi-layers, the LF process provides a high-resistivity substrate that enables large signal and fast charge collection by drift in a ~50 μm thick depleted layer. Since this process also enables the use of deep n- and p-wells to isolate the collection electrode from the thin active device layer, PMOS and NMOS transistors are available for the readout electronics in each pixel cell. In order to evaluate the sensor and transistor characteristics, several collection electrodes variants and readout architectures have been implemented. In this report, we focus on its design aspect of the LF-DMAPS prototype chip.

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

    EPA Science Inventory

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  12. Modulation transfer function of a trapezoidal pixel array detector

    NASA Astrophysics Data System (ADS)

    Wang, Fan; Guo, Rongli; Ni, Jinping; Dong, Tao

    2016-01-01

    The modulation transfer function (MTF) is the tool most commonly used for quantifying the performance of an electro-optical imaging system. Recently, trapezoid-shaped pixels were designed and used in a retina-like sensor in place of rectangular-shaped pixels. The MTF of a detector with a trapezoidal pixel array is determined according to its definition. Additionally, the MTFs of detectors with differently shaped pixels, but the same pixel areas, are compared. The results show that the MTF values of the trapezoidal pixel array detector are obviously larger than those of rectangular and triangular pixel array detectors at the same frequencies.

  13. Optical links for the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Stucci, Stefania

    2016-07-01

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

  14. SVGA AMOLED with world's highest pixel pitch

    NASA Astrophysics Data System (ADS)

    Prache, Olivier; Wacyk, Ihor

    2006-05-01

    We present the design and early evaluation results of the world's highest pixel pitch full-color 800x3x600- pixel, active matrix organic light emitting diode (AMOLED) color microdisplay for consumer and environmentally demanding applications. The design premises were aimed at improving small area uniformity as well as reducing the pixel size while expanding the functionality found in existing eMagin Corporations' microdisplay products without incurring any power consumption degradation when compared to existing OLED microdisplays produced by eMagin. The initial results of the first silicon prototype presented here demonstrate compliance with all major objectives as well as the validation of a new adaptive gamma correction technique that can operate automatically over temperature.

  15. Vivid, full-color aluminum plasmonic pixels

    PubMed Central

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

    2014-01-01

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

  16. Likelihood Analysis for Mega Pixel Maps

    NASA Technical Reports Server (NTRS)

    Kogut, Alan J.

    1999-01-01

    The derivation of cosmological parameters from astrophysical data sets routinely involves operations counts which scale as O(N(exp 3) where N is the number of data points. Currently planned missions, including MAP and Planck, will generate sky maps with N(sub d) = 10(exp 6) or more pixels. Simple "brute force" analysis, applied to such mega-pixel data, would require years of computing even on the fastest computers. We describe an algorithm which allows estimation of the likelihood function in the direct pixel basis. The algorithm uses a conjugate gradient approach to evaluate X2 and a geometric approximation to evaluate the determinant. Monte Carlo simulations provide a correction to the determinant, yielding an unbiased estimate of the likelihood surface in an arbitrary region surrounding the likelihood peak. The algorithm requires O(N(sub d)(exp 3/2) operations and O(Nd) storage for each likelihood evaluation, and allows for significant parallel computation.

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

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.

    1993-01-01

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

  18. Power Studies for the CMS Pixel Tracker

    SciTech Connect

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

    2009-01-01

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

  19. K2flix: Kepler pixel data visualizer

    NASA Astrophysics Data System (ADS)

    Barentsen, Geert

    2015-03-01

    K2flix makes it easy to inspect the CCD pixel data obtained by NASA's Kepler space telescope. The two-wheeled extended Kepler mission, K2, is affected by new sources of systematics, including pointing jitter and foreground asteroids, that are easier to spot by eye than by algorithm. The code takes Kepler's Target Pixel Files (TPF) as input and turns them into contrast-stretched animated gifs or MPEG-4 movies. K2flix can be used both as a command-line tool or using its Python API.

  20. Development of a CMOS SOI Pixel Detector

    SciTech Connect

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

    2008-08-19

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

  1. Commissioning of the ATLAS pixel detector

    SciTech Connect

    ATLAS Collaboration; Golling, Tobias

    2008-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  3. Pixel telescope test in STAR at RHIC

    NASA Astrophysics Data System (ADS)

    Sun, Xiangming; Szelezniak, Michal; Greiner, Leo; Matis, Howard; Vu, Chinh; Stezelberger, Thorsten; Wieman, Howard

    2007-10-01

    The STAR experiment at RHIC is designing a new inner vertex detector called the Heavy Flavor Tracker (HFT). The HFT's innermost two layers is called the PIXEL detector which uses Monolithic Active Pixel Sensor technology (MAPS). To test the MAPS technology, we just constructed and tested a telescope. The telescope uses a stack of three MIMOSTAR2 chips, Each MIMOSTAR2 sensor, which was designed by IPHC, is an array of 132x128 pixels with a square pixel size of 30 μ. The readout of the telescope makes use of the ALICE DDL/SIU cards, which is compatible with the future STAR data acquisition system called DAQ1000. The telescope was first studied in a 1.2 GeV/c electron beam at LBNL's Advanced Light Source. Afterwards, the telescope was outside the STAR magnet, and then later inside it, 145 cm away from STAR's center. We will describe this first test of MAPS technology in a collider environment, and report on the occupancy, particle flux, and performance of the telescope.

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

    SciTech Connect

    Fahim, Farah

    2014-10-31

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

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

    SciTech Connect

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

    2015-08-28

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

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

    NASA Astrophysics Data System (ADS)

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

    2006-03-01

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

  8. ACS/WFC Pixel Stability – Bringing the Pixels Back to the Science

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  9. Pixel detector Timepix operated in pile-up mode for pulsed imaging with ultra-soft X-rays

    NASA Astrophysics Data System (ADS)

    Krejci, F.; Jakubek, J.; Kroupa, M.; Bruza, P.; Panek, D.

    2012-12-01

    The hybrid semiconductor pixel detector Timepix operated in the Time-over-Threshold mode (ToT) enables direct energy measurement in each pixel. The advantage of noiseless position sensitive detection combined with per pixel spectroscopic capability opens the way to numerous new applications, which were till now, however, restricted to detection of radiation which is basically above the detector energy threshold (typically 3-4 keV). This limitation excludes application of the hybrid pixel technology to highly interesting fields such as plasma diagnostics or X-ray microscopy. In this contribution we demonstrate how the Timepix detector working in ToT mode can be operated as a detector for particles which are in principle below the detector threshold, namely for soft X-ray photons with energy typically 0.5 keV. The approach is based on the detection of a larger number of photons incoming in the pixel signal processing chain in a time significantly shorter than the shaping time of the pixel electronics, i.e. forming signal pile-up. The proposed approach enables a CCD-like integrating operation with the many advantages of the hybrid counting technology (direct conversion, high sensitivity, dark-current free, room temperature operation, fully digital output and possibility to utilize various read-out architectures). Using the proposed approach we performed single-shot X-ray radiography with a laser-induced plasma source in the spectral region of water window. The same technique was used for the characterization of the source itself.

  10. Test-beam results of a silicon pixel detector with Time-over-Threshold read-out having ultra-precise time resolution

    NASA Astrophysics Data System (ADS)

    Aglieri Rinella, G.; Cortina Gil, E.; Fiorini, M.; Kaplon, J.; Kluge, A.; Marchetto, F.; Albarran, M. E. Martin; Morel, M.; Noy, M.; Perktold, L.; Tiuraniem, S.; Velghe, B.

    2015-12-01

    A time-tagging hybrid silicon pixel detector developed for beam tracking in the NA62 experiment has been tested in a dedicated test-beam at CERN with 10 GeV/c hadrons. Measurements include time resolution, detection efficiency and charge sharing between pixels, as well as effects due to bias voltage variations. A time resolution of less than 150 ps has been measured with a 200 μm thick silicon sensor, using an on-pixel amplifier-discriminator and an end-of-column DLL-based time-to-digital converter.

  11. Noise in a CMOS digital pixel sensor

    NASA Astrophysics Data System (ADS)

    Chi, Zhang; Suying, Yao; Jiangtao, Xu

    2011-11-01

    Based on the study of noise performance in CMOS digital pixel sensor (DPS), a mathematical model of noise is established with the pulse-width-modulation (PWM) principle. Compared with traditional CMOS image sensors, the integration time is different and A/D conversion is implemented in each PWM DPS pixel. Then, the quantitative calculating formula of system noise is derived. It is found that dark current shot noise is the dominant noise source in low light region while photodiode shot noise becomes significantly important in the bright region. In this model, photodiode shot noise does not vary with luminance, but dark current shot noise does. According to increasing photodiode capacitance and the comparator's reference voltage or optimizing the mismatch in the comparator, the total noise can be reduced. These results serve as a guideline for the design of PWM DPS.

  12. Radiation experience with the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Veszpremi, V.

    2015-04-01

    The CMS pixel detector is the innermost component of the CMS tracker occupying the region around the centre of CMS, where the LHC beams are crossed, between 4.3 cm and 30 cm in radius and 46.5 cm along the beam axis. It operates in a high-occupancy and high-radiation environment created by particle collisions. Studies of radiation damage effects to the sensors were performed throughout the first running period of the LHC . Leakage current, depletion voltage, pixel readout thresholds, and hit finding efficiencies were monitored as functions of the increasing particle fluence. The methods and results of these measurements will be described together with their implications to detector operation as well as to performance parameters in offline hit reconstruction.

  13. Advanced monolithic pixel sensors using SOI technology

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  14. The Silicon Pixel Detector for ALICE Experiment

    SciTech Connect

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

    2007-10-26

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

  15. Performance measurements of hybrid PIN diode arrays

    SciTech Connect

    Shapiro, S.L. ); Arens, J.F.; Jernigan, J.G. . Space Sciences Lab.); Kramer, G. ); Collins, T.; Worley, S. ); Wilburn, C.D. ); Skubic, P. )

    1990-10-01

    We report the successful development of hybrid PIN diode arrays and a series of room-temperature measurements in a high-energy pion beam at FNAL. A PMOS VLSI 256 {times} 256 readout array having 30 {mu}m square pixels was indium-bump bonded to a mating PIN diode detector array. Preliminary measurements on the resulting hybrid show excellent signal-to-noise at room temperature. 3 refs., 5 figs.

  16. Effect of mixed (boundary) pixels on crop proportion estimation

    NASA Technical Reports Server (NTRS)

    Chhikara, R. S.

    1984-01-01

    In estimating acreage proportions of crop types in a segment using Landsat data, considerable problem is caused by the presence of mixed pixels. Due to lack of understanding of their spectral characteristics, mixed pixels have been treated in the past as pure while clustering and classifying the segment data. This paper examines this approach of treating mixed pixels as pure pixels and the effect of mixed pixels on the bias and variance of a crop type proportion estimate. First, the spectral response of a boundary pixel is modeled and an analytical expression for the bias and variance of a proportion estimate is obtained. This is followed by a numerical illustration of the effect of mixed pixels on bias and variance. It is shown that as the size of the mixed pixel class increases in a segment, the variance increases, however, such increase does not always affect the bias of the proportion estimate.

  17. CMOS Active Pixel Sensor Technology and Reliability Characterization Methodology

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  18. Soil moisture variability within remote sensing pixels

    SciTech Connect

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

    1992-11-30

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

  19. Status of the CMS pixel project

    SciTech Connect

    Uplegger, Lorenzo; /Fermilab

    2008-01-01

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

  20. Pixelated diffraction signatures for explosive detection

    NASA Astrophysics Data System (ADS)

    O'Flynn, Daniel; Reid, Caroline; Christodoulou, Christiana; Wilson, Matt; Veale, Matthew C.; Seller, Paul; Speller, Robert

    2012-06-01

    Energy dispersive X-ray diffraction (EDXRD) is a technique which can be used to improve the detection and characterisation of explosive materials. This study has performed EDXRD measurements of various explosive compounds using a novel, X-ray sensitive, pixelated, energy resolving detector developed at the Rutherford Appleton Laboratory, UK (RAL). EDXRD measurements are normally performed at a fixed scattering angle, but the 80×80 pixel detector makes it possible to collect both spatially resolved and energy resolved data simultaneously. The detector material used is Cadmium Telluride (CdTe), which can be utilised at room temperature and gives excellent spectral resolution. The setup uses characteristics from both energy dispersive and angular dispersive scattering techniques to optimise specificity and speed. The purpose of the study is to develop X-ray pattern "footprints" of explosive materials based on spatial and energy resolved diffraction data, which can then be used for the identification of such materials hidden inside packages or baggage. The RAL detector is the first energy resolving pixelated detector capable of providing an energy resolution of 1.0-1.5% at energies up to 150 keV. The benefit of using this device in a baggage scanner would be the provision of highly specific signatures to a range of explosive materials. We have measured diffraction profiles of five explosives and other compounds used to make explosive materials. High resolution spectra have been obtained. Results are presented to show the specificity of the technique in finding explosives within baggage.

  1. Performance measurements of hybrid PIN diode arrays

    SciTech Connect

    Jernigan, J.G.; Arens, J.F. . Space Sciences Lab.); Kramer, G. ); Collins, T.; Herring, J. ); Shapiro, S.L. ); Wilburn, C.D. )

    1990-05-01

    We report on the successful effort to develop hybrid PIN diode arrays and to demonstrate their potential as components of vertex detectors. Hybrid pixel arrays have been fabricated by the Hughes Aircraft Co. by bump bonding readout chips developed by Hughes to an array of PIN diodes manufactured by Micron Semiconductor Inc. These hybrid pixel arrays were constructed in two configurations. One array format having 10 {times} 64 pixels, each 120 {mu}m square, and the other format having 256 {times} 256 pixels, each 30 {mu}m square. In both cases, the thickness of the PIN diode layer is 300 {mu}m. Measurements of detector performance show that excellent position resolution can be achieved by interpolation. By determining the centroid of the charge cloud which spreads charge into a number of neighboring pixels, a spatial resolution of a few microns has been attained. The noise has been measured to be about 300 electrons (rms) at room temperature, as expected from KTC and dark current considerations, yielding a signal-to-noise ratio of about 100 for minimum ionizing particles. 4 refs., 13 figs.

  2. Digital pixel CMOS focal plane array with on-chip multiply accumulate units for low-latency image processing

    NASA Astrophysics Data System (ADS)

    Little, Jeffrey W.; Tyrrell, Brian M.; D'Onofrio, Richard; Berger, Paul J.; Fernandez-Cull, Christy

    2014-06-01

    A digital pixel CMOS focal plane array has been developed to enable low latency implementations of image processing systems such as centroid trackers, Shack-Hartman wavefront sensors, and Fitts correlation trackers through the use of in-pixel digital signal processing (DSP) and generic parallel pipelined multiply accumulate (MAC) units. Light intensity digitization occurs at the pixel level, enabling in-pixel DSP and noiseless data transfer from the pixel array to the peripheral processing units. The pipelined processing of row and column image data prior to off chip readout reduces the required output bandwidth of the image sensor, thus reducing the latency of computations necessary to implement various image processing systems. Data volume reductions of over 80% lead to sub 10μs latency for completing various tracking and sensor algorithms. This paper details the architecture of the pixel-processing imager (PPI) and presents some initial results from a prototype device fabricated in a standard 65nm CMOS process hybridized to a commercial off-the-shelf short-wave infrared (SWIR) detector array.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  4. Preliminary test results from a telescope of Hughes pixel arrays at FNAL

    SciTech Connect

    Jernigan, J.G.; Arens, J.; Vezie, D. . Space Sciences Lab.); Shapiro, S.L. ); Collins, T. ); Krider, J. ); Skubic, P. )

    1992-09-01

    In December of 1991 three silicon hybrid pixel detectors each having 2.56 [times] 2.56 pixels 30 [mu]m square, made by the Hughes Aircraft Company, were placed in a high energy muon beam at the Fermi National Accelerator Laboratory. Straight tracks were recorded in these detectors at angles to the normal to the plane of the silicon ranging from 0 to 45[degrees]. In this note, preliminary results are presented on the straight through tracks, i.e., those passing through the telescope at normal incidence. Pulse height data, signal-to-noise data, and preliminary straight line fits to the data resulting in residual distributions are presented. Preliminary calculations show spatial resolution of less than 5 [mu]m in two dimensions.

  5. Preliminary test results from a telescope of Hughes pixel arrays at FNAL

    SciTech Connect

    Jernigan, J.G.; Arens, J.; Vezie, D.; Shapiro, S.L.; Collins, T.; Krider, J.; Skubic, P.

    1992-09-01

    In December of 1991 three silicon hybrid pixel detectors each having 2.56 {times} 2.56 pixels 30 {mu}m square, made by the Hughes Aircraft Company, were placed in a high energy muon beam at the Fermi National Accelerator Laboratory. Straight tracks were recorded in these detectors at angles to the normal to the plane of the silicon ranging from 0 to 45{degrees}. In this note, preliminary results are presented on the straight through tracks, i.e., those passing through the telescope at normal incidence. Pulse height data, signal-to-noise data, and preliminary straight line fits to the data resulting in residual distributions are presented. Preliminary calculations show spatial resolution of less than 5 {mu}m in two dimensions.

  6. Readout cross-talk for alpha-particle measurements in a pixelated sensor system

    NASA Astrophysics Data System (ADS)

    Norlin, B.; Reza, S.; Krapohl, D.; Fröjdh, E.; Thungström, G.

    2015-05-01

    Simulations in Medici are performed to quantify crosstalk and charge sharing in a hybrid pixelated silicon detector. Crosstalk and charge sharing degrades the spatial and spectral resolution of single photon processing X-ray imaging systems. For typical medical X-ray imaging applications, the process is dominated by charge sharing between the pixels in the sensor. For heavier particles each impact generates a large amount of charge and the simulation seems to over predict the charge collection efficiency. This indicates that some type of non modelled degradation of the charge transport efficiency exists, like the plasma effect where the plasma might shield the generated charges from the electric field and hence distorts the charge transport process. Based on the simulations it can be reasoned that saturation of the amplifiers in the Timepix system might generate crosstalk that increases the charge spread measured from ion impact on the sensor.

  7. The RD53 collaboration's SystemVerilog-UVM simulation framework and its general applicability to design of advanced pixel readout chips

    NASA Astrophysics Data System (ADS)

    Marconi, S.; Conti, E.; Placidi, P.; Christiansen, J.; Hemperek, T.

    2014-10-01

    The foreseen Phase 2 pixel upgrades at the LHC have very challenging requirements for the design of hybrid pixel readout chips. A versatile pixel simulation platform is as an essential development tool for the design, verification and optimization of both the system architecture and the pixel chip building blocks (Intellectual Properties, IPs). This work is focused on the implemented simulation and verification environment named VEPIX53, built using the SystemVerilog language and the Universal Verification Methodology (UVM) class library in the framework of the RD53 Collaboration. The environment supports pixel chips at different levels of description: its reusable components feature the generation of different classes of parameterized input hits to the pixel matrix, monitoring of pixel chip inputs and outputs, conformity checks between predicted and actual outputs and collection of statistics on system performance. The environment has been tested performing a study of shared architectures of the trigger latency buffering section of pixel chips. A fully shared architecture and a distributed one have been described at behavioral level and simulated; the resulting memory occupancy statistics and hit loss rates have subsequently been compared.

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

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  10. Planar pixel detector module development for the HL-LHC ATLAS pixel system

    NASA Astrophysics Data System (ADS)

    Bates, Richard L.; Buttar, C.; Stewart, A.; Blue, A.; Doonan, K.; Ashby, J.; Casse, G.; Dervan, P.; Forshaw, D.; Tsurin, I.; Brown, S.; Pater, J.

    2013-12-01

    The ATLAS pixel detector for the HL-LHC requires the development of large area pixel modules that can withstand doses up to 1016 1 MeV neq cm-2. The area of the pixel detector system will be over 5 m2 and as such low cost, large area modules are required. The development of a quad module based on 4 FE-I4 readout integrated chips (ROIC) will be discussed. The FE-I4 ROIC is a large area chip and the yield of the flip-chip process to form an assembly is discussed for single chip assemblies. The readout of the quad module for laboratory tests will be reported.

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

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    2011-01-01

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

  12. EDITORIAL: Micro-pixellated LEDs for science and instrumentation

    NASA Astrophysics Data System (ADS)

    Dawson, Martin D.; Neil, Mark A. A.

    2008-05-01

    This Cluster Issue of Journal of Physics D: Applied Physics highlights micro-pixellated gallium nitride light-emitting diodes or `micro-LEDs', an emerging technology offering considerable attractions for a broad range of scientific and instrumentation applications. It showcases the results of a Research Councils UK (RCUK) Basic Technology Research programme (http://bt-onethousand.photonics.ac.uk), running from 2004-2008, which has drawn together a multi-disciplinary and multi-institutional research partnership to develop these devices and explore their potential. Images of LEDs Examples of GaN micro-pixel LEDs in operation. Images supplied courtesy of the Guest Editors. The partnership, of physicists, engineers and chemists drawn from the University of Strathclyde, Heriot-Watt University, the University of Sheffield and Imperial College London, has sought to move beyond the established mass-market uses of gallium nitride LEDs in illumination and lighting. Instead, it focuses on specialised solid-state micro-projection devices the size of a match-head, containing up to several thousand individually-addressable micro-pixel elements emitting light in the ultraviolet or visible regions of the spectrum. Such sources are pattern-programmable under computer control and can project into materials fixed or high-frame rate optical images or spatially-controllable patterns of nanosecond excitation pulses. These materials can be as diverse as biological cells and tissues, biopolymers, photoresists and organic semiconductors, leading to new developments in optical microscopy, bio-sensing and chemical sensing, mask-free lithography and direct writing, and organic electronics. Particular areas of interest are multi-modal microscopy, integrated forms of organic semiconductor lasers, lab-on-a-chip, GaN/Si optoelectronics and hybrid inorganic/organic semiconductor structures. This Cluster Issue contains four invited papers and ten contributed papers. The invited papers serve to set

  13. High-sensitivity active pixel sensor with variable threshold photodetector

    NASA Astrophysics Data System (ADS)

    Jo, Sung-Hyun; Bae, Myunghan; Choi, Byoung-Soo; Lyu, Hong-Kun; Shin, Jang-Kyoo

    2015-05-01

    A novel high-sensitivity active pixel sensor (APS) with a variable threshold photodetector has been presented and for the first time, a simple SPICE model for the variable threshold photodetector is presented. Its SPICE model is in good agreement with measurements and is more simpler than the conventional model. The proposed APS has a gate/body-tied PMOSFET-type photodetector with an overlapping control gate that makes it possible to control the sensitivity of the proposed APS. It is a hybrid device composed of a metal-oxide-semiconductor field-effect transistor (MOSFET), a lateral bipolar junction transistor (BJT) and a vertical BJT. Using sufficient overlapping control gate bias to operate the MOSFET in inversion mode, the variable threshold photodetector allows for increasing the photocurrent gain by 105 at low light intensities when the control gate bias is -3 V. Thus, the proposed APS with a variable threshold photodetector has better low-light-level sensitivity than the conventional APS operating mode, and it has a variable sensitivity which is determined by the control gate bias. The proposed sensor has been fabricated by using 0.35 μm 2-poly 4-metal standard complementary MOS (CMOS) process and its characteristics have been evaluated.

  14. Development of a cadmium telluride pixel detector for astrophysical applications

    NASA Astrophysics Data System (ADS)

    Miyasaka, Hiromasa; Harrison, Fiona A.; Cook, Walter R.; Mao, Peter H.; Rana, Vikram R.; Ishikawa, Shin-Nosuke; Ushio, Masayoshi; Aono, Hiroyuki; Watanabe, Shin; Sato, Goro; Kokubun, Motohide; Takahashi, Tadayuki

    2009-08-01

    We are developing imaging Cadmium Telluride (CdTe) pixel detectors optimized for astrophysical hard X-ray applications. Our hybrid detector consist of a CdTe crystal 1mm thick and 2cm × 2cm in area with segmented anode contacts directly bonded to a custom low-noise application specific integrated circuit (ASIC). The CdTe sensor, fabricated by ACRORAD (Okinawa, Japan), has Schottky blocking contacts on a 605 micron pitch in a 32 × 32 array, providing low leakage current and enabling readout of the anode side. The detector is bonded using epoxy-gold stud interconnects to a custom low noise, low power ASIC circuit developed by Caltech's Space Radiation Laboratory. We have achieved very good energy resolution over a wide energy range (0.62keV FWHM @ 60keV, 10.8keV FWHM @ 662keV). We observe polarization effects at room temperature, but they are suppressed if we operate the detector at or below 0°C degree. These detectors have potential application for future missions such as the International X-ray Observatory (IXO).

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  16. Active pixel sensor array with electronic shuttering

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor)

    2002-01-01

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

  17. Small pixel uncooled imaging FPAs and applications

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

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

  18. Single-pixel complementary compressive sampling spectrometer

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  20. Efficient single pixel imaging in Fourier space

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  1. Further applications for mosaic pixel FPA technology

    NASA Astrophysics Data System (ADS)

    Liddiard, Kevin C.

    2011-06-01

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

  2. Active pixel sensor array with multiresolution readout

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  3. PILATUS: A single photon counting pixel detector for X-ray applications

    NASA Astrophysics Data System (ADS)

    Henrich, B.; Bergamaschi, A.; Broennimann, C.; Dinapoli, R.; Eikenberry, E. F.; Johnson, I.; Kobas, M.; Kraft, P.; Mozzanica, A.; Schmitt, B.

    2009-08-01

    The hybrid pixel technology combines silicon sensors with CMOS-processing chips by a 2D micro bump-bonding interconnection technology developed at Paul Scherrer Institute [C. Broennimann, E.F. Eikenberry, B. Henrich, R. Horisberger, G. Huelsen, E. Pohl, B. Schmitt, C. Schulze-Briese, M. Suzuki, T. Tomizaki, H. Toyokawa, A. Wagner. J. Synchrotron Rad. 13 (2005) 120 [1]; T. Rohe, C. Broennimann, F. Glaus, J. Gobrecht, S. Heising, M. Horisberger, R. Horisberger, H.C. Kaestl, J. Lehmann, S. Streuli, Nucl. Instr. and Meth. Phys. Res. A 565 (2006) 303 [2

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  5. Analysis of pixel circuits in CMOS image sensors

    NASA Astrophysics Data System (ADS)

    Mei, Zou; Chen, Nan; Yao, Li-bin

    2015-04-01

    CMOS image sensors (CIS) have lower power consumption, lower cost and smaller size than CCD image sensors. However, generally CCDs have higher performance than CIS mainly due to lower noise. The pixel circuit used in CIS is the first part of the signal processing circuit and connected to photodiode directly, so its performance will greatly affect the CIS or even the whole imaging system. To achieve high performance, CMOS image sensors need advanced pixel circuits. There are many pixel circuits used in CIS, such as passive pixel sensor (PPS), 3T and 4T active pixel sensor (APS), capacitive transimpedance amplifier (CTIA), and passive pixel sensor (PPS). At first, the main performance parameters of each pixel structure including the noise, injection efficiency, sensitivity, power consumption, and stability of bias voltage are analyzed. Through the theoretical analysis of those pixel circuits, it is concluded that CTIA pixel circuit has good noise performance, high injection efficiency, stable photodiode bias, and high sensitivity with small integrator capacitor. Furthermore, the APS and CTIA pixel circuits are simulated in a standard 0.18-μm CMOS process and using a n-well/p-sub photodiode by SPICE and the simulation result confirms the theoretical analysis result. It shows the possibility that CMOS image sensors can be extended to a wide range of applications requiring high performance.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  7. How big is an OMI pixel?

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  8. Pixel-level robust digital image correlation.

    PubMed

    Cofaru, Corneliu; Philips, Wilfried; Van Paepegem, Wim

    2013-12-01

    Digital Image Correlation (DIC) is a well-established non-contact optical metrology method. It employs digital image analysis to extract the full-field displacements and strains that occur in objects subjected to external stresses. Despite recent DIC progress, many problematic areas which greatly affect accuracy and that can seldomly be avoided, received very little attention. Problems posed by the presence of sharp displacement discontinuities, reflections, object borders or edges can be linked to the analysed object's properties and deformation. Other problematic areas, such as image noise, localized reflections or shadows are related more to the image acquisition process. This paper proposes a new subset-based pixel-level robust DIC method for in-plane displacement measurement which addresses all of these problems in a straightforward and unified approach, significantly improving DIC measurement accuracy compared to classic approaches. The proposed approach minimizes a robust energy functional which adaptively weighs pixel differences in the motion estimation process. The aim is to limit the negative influence of pixels that present erroneous or inconsistent motions by enforcing local motion consistency. The proposed method is compared to the classic Newton-Raphson DIC method in terms of displacement accuracy in three experiments. The first experiment is numerical and presents three combined problems: sharp displacement discontinuities, missing image information and image noise. The second experiment is a real experiment in which a plastic specimen is developing a lateral crack due to the application of uniaxial stress. The region around the crack presents both reflections that saturate the image intensity levels leading to missing image information, as well as sharp motion discontinuities due to the plastic film rupturing. The third experiment compares the proposed and classic DIC approaches with generic computer vision optical flow methods using images from

  9. Research of IRFPAs' reliability evaluation by bad pixel

    NASA Astrophysics Data System (ADS)

    Hao, Lichao; Huang, Aibo; Lai, Canxiong; Chen, Xing; Hao, Mingming; Chen, Honglei; Lu, Guoguang; Huang, Yun; En, Yunfei

    2015-10-01

    Reliability is an important index to ensure the application of infrared focal plane arrays (IRFPAs) in complex environment, and it becomes a major bottleneck problem of IRFPAs' development. Because of the characteristics such as type, nature, quantity, location and distribution et al, bad pixel which contains initial bad pixel and used bad pixel has outstanding advantage for failure analysis and reliability evaluation of IRFPAs. In this paper, the structure of IRPFAs has been introduced in detail, and the damage mechanisms of used bad pixel also have been analyzed deeply. At the same time, the feasibility to study IRPFAs' damage stress, failure position, damage mechanism has been discussed all around. The research of bad pixel can be used to optimize the structure and process, meanwhile it also can improve the accuracy of bad pixel identification and replacements.

  10. A Pixel Readout Chip in 40 nm CMOS Process for High Count Rate Imaging Systems with Minimization of Charge Sharing Effects

    SciTech Connect

    Maj, Piotr; Grybos, P.; Szczgiel, R.; Kmon, P.; Drozd, A.; Deptuch, G.

    2013-11-07

    We present a prototype chip in 40 nm CMOS technology for readout of hybrid pixel detector. The prototype chip has a matrix of 18x24 pixels with a pixel pitch of 100 m. It can operate both in single photon counting (SPC) mode and in C8P1 mode. In SPC the measured ENC is 84 e rms (for the peaking time of 48 ns), while the effective offset spread is below 2 mV rms. In the C8P1 mode the chip reconstructs full charge deposited in the detector, even in the case of charge sharing, and it identifies a pixel with the largest charge deposition. The chip architecture and preliminary measurements are reported.

  11. Pixel-level plasmonic microcavity infrared photodetector

    PubMed Central

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

    2016-01-01

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

  12. CMB component separation in the pixel domain

    SciTech Connect

    Doroshkevich, A.; Verkhodanov, O.

    2011-02-15

    We show that the popular internal linear combination approach is unstable with respect to division of the observed map pixels to a set of 'homogeneous' subsamples. For various choices of such subsamples we can obtain a restored CMB signal with amplitudes ranging from zero to the amplitude of the observed signal. We propose an approach which allows us to obtain corrected estimates of the CMB power spectrum C{sub l} at l{<=}30 and provides results similar to WMAP for larger l. Using this approach, we eliminate some anomalies of the WMAP results. In particular, our estimate of the quadrupole is consistent with the theoretically expected one. The effect of the 'axis of evil' is suppressed, and the symmetry of the north and south galactic hemispheres increases. These results can change estimates of quadrupole polarization and the redshift of reionization of the Universe. We also propose a new simple approach which can improve the WMAP estimates of the high l power spectrum.

  13. Pixel-level plasmonic microcavity infrared photodetector.

    PubMed

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

    2016-01-01

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

  14. 196 Million Pixels: An Immersive Visualization Experience

    NASA Astrophysics Data System (ADS)

    Reed, P. J.; Vandenberg, A.; Wang, G.

    2011-12-01

    Georgia State University (GSU) has recently implemented one of the world's largest high-resolution, tiled visualization walls specifically designed for researcher accessibility and display of data in an interactive, immersive, exploratory and collaborative experience. The Visualization Wall, comprised of 48 individual high-resolution monitors, is able to analyze, evaluate, and present data using the latest earth science research software packages. Multi-core processing and 24 graphical processing units (GPU's) allow the system to process and view data using research software applications at high resolution (+196 million pixels), while maintaining an interactive experience for the user. A Windows platform solves many application compatibility obstacles but also presents a new host of problems when scaling applications across multiple monitors. Continuous data set visualization, frame rate slowing, and graphic performance have been a challenge with the Visualization Wall. To overcome these obstacles, GSU has implemented several innovative solutions including Google Code projects, hardware accelerated browsers, and open-source software such as SAGE.

  15. CMOS monolithic pixel sensors research and development at LBNL

    NASA Astrophysics Data System (ADS)

    Contarato, D.; Bussat, J.-M.; Denes, P.; Greiner, L.; Kim, T.; Stezelberger, T.; Wieman, H.; Battaglia, M.; Hooberman, B.; Tompkins, L.

    2007-12-01

    This paper summarizes the recent progress in the design and characterization of CMOS pixel sensors at LBNL. Results of lab tests, beam tests and radiation hardness tests carried out at LBNL on a test structure with pixels of various sizes are reported. The first results of the characterization of back-thinned CMOS pixel sensors are also reported, and future plans and activities are discussed.

  16. Impact of aperturing and pixel size on XPCS using AGIPD

    NASA Astrophysics Data System (ADS)

    Becker, J.; Graafsma, H.

    2012-02-01

    A case study for the Adaptive Gain Integrating Pixel Detector (AGIPD) at the European XFEL employing the intensity autocorrelation technique was performed using the detector simulation tool HORUS. The study compares the AGIPD (pixel size of (200 μm)2) to a possible apertured version of the detector and to a hypothetical system with 100 μm pixel size and investigates the influence of intensity fluctuations and incoherent noise on the quality of the acquired data.

  17. The status of the CMS forward pixel detector

    SciTech Connect

    Tan, Ping; /Fermilab

    2006-01-01

    The silicon pixel detector is the innermost component of the CMS tracking system. It provides precise measurements of space points to allow effective pattern recognition in multiple track environments near the LHC interaction point. The end disks of the pixel detector, known as the Forward Pixel detector, are constructed mainly by the US-CMS collaborators. The design techniques, readout electronics, test beam activities, and construction status are reviewed.

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

    NASA Astrophysics Data System (ADS)

    Garcia-Sciveres, Maurice; Wang, Xinkang

    2016-04-01

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

  19. Fast Pixel Buffer For Processing With Lookup Tables

    NASA Technical Reports Server (NTRS)

    Fisher, Timothy E.

    1992-01-01

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

  20. Mapping Capacitive Coupling Among Pixels in a Sensor Array

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  1. CMOS Active Pixel Sensor Star Tracker with Regional Electronic Shutter

    NASA Technical Reports Server (NTRS)

    Yadid-Pecht, Orly; Pain, Bedabrata; Staller, Craig; Clark, Christopher; Fossum, Eric

    1996-01-01

    The guidance system in a spacecraft determines spacecraft attitude by matching an observed star field to a star catalog....An APS(active pixel sensor)-based system can reduce mass and power consumption and radiation effects compared to a CCD(charge-coupled device)-based system...This paper reports an APS (active pixel sensor) with locally variable times, achieved through individual pixel reset (IPR).

  2. Hit efficiency study of CMS prototype forward pixel detectors

    SciTech Connect

    Kim, Dongwook; /Johns Hopkins U.

    2006-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  4. Applications of pixellated GaAs X-ray detectors in a synchrotron radiation beam

    NASA Astrophysics Data System (ADS)

    Watt, J.; Bates, R.; Campbell, M.; Mathieson, K.; Mikulec, B.; O'Shea, V.; Passmore, M.-S.; Schwarz, C.; Smith, K. M.; Whitehill, C.; XIMAGE Project

    2001-03-01

    Hybrid semiconductor pixel detectors are being investigated as imaging devices for radiography and synchrotron radiation beam applications. Based on previous work in the CERN RD19 and the UK IMPACT collaborations, a photon counting GaAs pixel detector (PCD) has been used in an X-ray powder diffraction experiment. The device consists of a 200 μm thick SI-LEC GaAs detector patterned in a 64×64 array of 170 μm pitch square pixels, bump-bonded to readout electronics operating in single photon counting mode. Intensity peaks in the powder diffraction pattern of KNbO 3 have been resolved and compared with results using the standard scintillator, and a PCD predecessor (the Ω3). The PCD shows improved speed, dynamic range, 2-D information and comparable spatial resolution to the standard scintillator based systems. It also overcomes the severe dead time limitations of the Ω3 by using a shutter based acquisition mode. A brief demonstration of the possibilities of the system for dental radiography and image processing are given, showing a marked reduction in patient dose and dead time compared with film.

  5. Characteristics of Monolithically Integrated InGaAs Active Pixel Imager Array

    NASA Technical Reports Server (NTRS)

    Kim, Q.; Cunningham, T. J.; Pain, B.; Lange, M. J.; Olsen, G. H.

    2000-01-01

    Switching and amplifying characteristics of a newly developed monolithic InGaAs Active Pixel Imager Array are presented. The sensor array is fabricated from InGaAs material epitaxially deposited on an InP substrate. It consists of an InGaAs photodiode connected to InP depletion-mode junction field effect transistors (JFETs) for low leakage, low power, and fast control of circuit signal amplifying, buffering, selection, and reset. This monolithically integrated active pixel sensor configuration eliminates the need for hybridization with silicon multiplexer. In addition, the configuration allows the sensor to be front illuminated, making it sensitive to visible as well as near infrared signal radiation. Adapting the existing 1.55 micrometer fiber optical communication technology, this integration will be an ideal system of optoelectronic integration for dual band (Visible/IR) applications near room temperature, for use in atmospheric gas sensing in space, and for target identification on earth. In this paper, two different types of small 4 x 1 test arrays will be described. The effectiveness of switching and amplifying circuits will be discussed in terms of circuit effectiveness (leakage, operating frequency, and temperature) in preparation for the second phase demonstration of integrated, two-dimensional monolithic InGaAs active pixel sensor arrays for applications in transportable shipboard surveillance, night vision, and emission spectroscopy.

  6. Radiation tolerance of prototype BTeV pixel detector readout chips

    SciTech Connect

    Gabriele Chiodini et al.

    2002-07-12

    High energy and nuclear physics experiments need tracking devices with increasing spatial precision and readout speed in the face of ever-higher track densities and increased radiation environments. The new generation of hybrid pixel detectors (arrays of silicon diodes bump bonded to arrays of front-end electronic cells) is the state of the art technology able to meet these challenges. We report on irradiation studies performed on BTeV pixel readout chip prototypes exposed to a 200 MeV proton beam at Indiana University Cyclotron Facility. Prototype pixel readout chip preFPIX2 has been developed at Fermilab for collider experiments and implemented in standard 0.25 micron CMOS technology following radiation tolerant design rules. The tests confirmed the radiation tolerance of the chip design to proton total dose up to 87 MRad. In addition, non destructive radiation-induced single event upsets have been observed in on-chip static registers and the single bit upset cross section has been extensively measured.

  7. Prototype AEGIS: A Pixel-Array Readout Circuit for Gamma-Ray Imaging

    PubMed Central

    Barber, H. Bradford; Augustine, F. L.; Furenlid, L.; Ingram, C. M.; Grim, G. P.

    2015-01-01

    Semiconductor detector arrays made of CdTe/CdZnTe are expected to be the main components of future high-performance, clinical nuclear medicine imaging systems. Such systems will require small pixel-pitch and much larger numbers of pixels than are available in current semiconductor-detector cameras. We describe the motivation for developing a new readout integrated circuit, AEGIS, for use in hybrid semiconductor detector arrays, that may help spur the development of future cameras. A basic design for AEGIS is presented together with results of an HSPICE™ simulation of the performance of its unit cell. AEGIS will have a shaper-amplifier unit cell and neighbor pixel readout. Other features include the use of a single input power line with other biases generated on-board, a control register that allows digital control of all thresholds and chip configurations and an output approach that is compatible with list-mode data acquisition. An 8×8 prototype version of AEGIS is currently under development; the full AEGIS will be a 64×64 array with 300 μm pitch. PMID:26345126

  8. High-speed readout of high-Z pixel detectors with the LAMBDA detector

    NASA Astrophysics Data System (ADS)

    Pennicard, D.; Smoljanin, S.; Sheviakov, I.; Xia, Q.; Rothkirch, A.; Yu, Y.; Struth, B.; Hirsemann, H.; Graafsma, H.

    2014-12-01

    High-frame-rate X-ray pixel detectors make it possible to perform time-resolved experiments at synchrotron beamlines, and to make better use of these sources by shortening experiment times. LAMBDA is a photon-counting hybrid pixel detector based on the Medipix3 chip, designed to combine a small pixel size of 55 μm, a large tileable module design, high speed, and compatibility with ``high-Z'' sensors for hard X-ray detection. This technical paper focuses on LAMBDA's high-speed-readout functionality, which allows a frame rate of 2000 frames per second with no deadtime between successive images. This takes advantage of the Medipix3 chip's ``continuous read-write'' function and highly parallelised readout. The readout electronics serialise this data and send it back to a server PC over two 10 Gigabit Ethernet links. The server PC controls the detector and receives, processes and stores the data using software designed for the Tango control system. As a demonstration of high-speed readout of a high-Z sensor, a GaAs LAMBDA detector was used to make a high-speed X-ray video of a computer fan.

  9. Development of thin pixel detectors on epitaxial silicon for HEP experiments

    NASA Astrophysics Data System (ADS)

    Boscardin, Maurizio; Calvo, Daniela; Giacomini, Gabriele; Wheadon, Richard; Ronchin, Sabina; Zorzi, Nicola

    2013-08-01

    The foreseen luminosity of the new experiments in High Energy Physics will require that the innermost layer of vertex detectors will be able to sustain fluencies up to 1016 neq/cm2. Moreover, in many experiments there is a demand for the minimization of the material budget of the detectors. Therefore, thin pixel devices fabricated on n-type silicon are a natural choice to fulfill these requirements due to their rad-hard performances and low active volume. We present an R&D activity aimed at developing a new thin hybrid pixel device in the framework of PANDA experiments. The detector of this new device is a p-on-n pixel sensor realized starting from epitaxial silicon wafers and back thinned up to 50-100 μm after process completion. We present the main technological steps and some electrical characterization on the fabricated devices before and after back thinning and after bump bonding to the front-end electronics.

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  11. Pixel-by-pixel deconvolution of bolus-tracking data: optimization and implementation

    NASA Astrophysics Data System (ADS)

    Sourbron, S.; Dujardin, M.; Makkat, S.; Luypaert, R.

    2007-01-01

    Quantification of haemodynamic parameters with a deconvolution analysis of bolus-tracking data is an ill-posed problem which requires regularization. In a previous study, simulated data without structural errors were used to validate two methods for a pixel-by-pixel analysis: standard-form Tikhonov regularization with either the L-curve criterion (LCC) or generalized cross validation (GCV) for selecting the regularization parameter. However, problems of image artefacts were reported when the methods were applied to patient data. The aim of this study was to investigate the nature of these problems in more detail and evaluate strategies of optimization for routine application in the clinic. In addition we investigated to which extent the calculation time of the algorithm can be minimized. In order to ensure that the conclusions are relevant for a larger range of clinical applications, we relied on patient data for evaluation of the algorithms. Simulated data were used to validate the conclusions in a more quantitative manner. We conclude that the reported problems with image quality can be removed by appropriate optimization of either LCC or GCV. In all examples this could be achieved with LCC without significant perturbation of the values in pixels where the regularization parameter was originally selected accurately. GCV could not be optimized for the renal data, and in the CT data only at the cost of image resolution. Using the implementations given, calculation times were sufficiently short for routine application in the clinic.

  12. Optimal fine ϕ-slicing for single-photon-counting pixel detectors

    PubMed Central

    Mueller, Marcus; Wang, Meitian; Schulze-Briese, Clemens

    2012-01-01

    The data-collection parameters used in a macromolecular diffraction experiment have a strong impact on data quality. A careful choice of parameters leads to better data and can make the difference between success and failure in phasing attempts, and will also result in a more accurate atomic model. The selection of parameters has to account for the application of the data in various phasing methods or high-resolution refinement. Furthermore, experimental factors such as crystal characteristics, available experiment time and the properties of the X-ray source and detector have to be considered. For many years, CCD detectors have been the prevalent type of detectors used in macromolecular crystallography. Recently, hybrid pixel X-ray detectors that operate in single-photon-counting mode have become available. These detectors have fundamentally different characteristics compared with CCD detectors and different data-collection strategies should be applied. Fine ϕ-slicing is a strategy that is particularly well suited to hybrid pixel detectors because of the fast readout time and the absence of readout noise. A large number of data sets were systematically collected from crystals of four different proteins in order to investigate the benefit of fine ϕ-­slicing on data quality with a noise-free detector. The results show that fine ϕ-slicing can substantially improve scaling statistics and anomalous signal provided that the rotation angle is comparable to half the crystal mosaicity. PMID:22194332

  13. To zoom or not to zoom: do we have enough pixels?

    NASA Astrophysics Data System (ADS)

    Youngworth, Richard N.; Herman, Eric

    2015-09-01

    Common lexicon in imaging systems includes the frequently used term digital zoom. Of course this term is somewhat of a misnomer as there is no actual zooming in such systems. Instead, digital zoom describes the zoom effect that comes with an image rewriting or reprinting that perhaps can be more accurately described as cropping and enlarging an image (a pixel remapping) for viewing. If done properly, users of the overall hybrid digital-optical system do not know the methodology employed. Hence the essential question, pondered and manipulated since the advent of mature digital image science, really becomes "do we have enough pixels to avoid optical zoom." This paper discusses known imaging factors for hybrid digital-optical systems, most notably resolution considerations. The paper is fundamentally about communication, and thereby includes information useful to the greater consumer, technical, and business community who all have an interest in understanding the key technical details that have driven the amazing technology and development of zoom systems.

  14. A 400 KHz line rate 2048 pixel modular SWIR linear array for earth observation applications

    NASA Astrophysics Data System (ADS)

    Anchlia, Ankur; Vinella, Rosa M.; Wouters, Kristof; Gielen, Daphne; Hooylaerts, Peter; Deroo, Pieter; Ruythooren, Wouter; van der Zanden, Koen; Vermeiren, Jan; Merken, Patrick

    2015-10-01

    In this paper, we report about a family of linear imaging FPAs sensitive in the [0.9 - 1.7um] band, developed for high speed applications such as LIDAR, wavelength references and OCT analyzers and also for earth observation applications. Fast linear FPAs can also be used in a wide variety of terrestrial applications, including high speed sorting, electro- and photo-luminesce and medical applications. The arrays are based on a modular ROIC design concept: modules of 512 pixels are stitched during fabrication to achieve 512, 1024 and 2048 pixel arrays. In principle, this concept can be extended to any multiple of 512 pixels, the limiting factor being the pixel yield of long InGaAs arrays and the CTE differences in the hybrid setup. Each 512-pixel module has its own on-chip digital sequencer, analog readout chain and 4 output buffers. This modular concept enables a long-linear array to run at a high line rate of 400 KHz irrespective of the array length, which limits the line rate in a traditional linear array. The pixel has a pitch of 12.5um. The detector frontend is based on CTIA (Capacitor Trans-impedance Amplifier), having 5 selectable integration capacitors giving full well from 62x103e- (gain0) to 40x106e- (gain4). An auto-zero circuit limits the detector bias non-uniformity to 5-10mV across broad intensity levels, limiting the input referred dark signal noise to 20e-rms for Tint=3ms at room temperature. An on-chip CDS that follows the CTIA facilitates removal of Reset/KTC noise, CTIA offsets and most of the 1/f noise. The measured noise of the ROIC is 35e-rms in gain0. At a master clock rate of 60MHz and a minimum integration time of 1.4us, the FPAs reach the highest line rate of 400 KHz.

  15. Development and simulation results of a sparsification and readout circuit for wide pixel matrices

    NASA Astrophysics Data System (ADS)

    Gabrielli, A.; Giorgi, F.; Morsani, F.; Villa, M.

    2011-06-01

    In future collider experiments, the increasing luminosity and centre of mass energy are rising challenging problems in the design of new inner tracking systems. In this context we develop high-efficiency readout architectures for large binary pixel matrices that are meant to cope with the high-stressing conditions foreseen in the innermost layers of a tracker [The SuperB Conceptual Design Report, INFN/AE-07/02, SLAC-R-856, LAL 07-15, Available online at: http://www.pi.infn.it/SuperB]. We model and design digital readout circuits to be integrated on VLSI ASICs. These architectures can be realized with different technology processes and sensors: they can be implemented on the same silicon sensor substrate of a CMOS MAPS devices (Monolithic Active Pixel Sensor), on the CMOS tier of a hybrid pixel sensor or in a 3D chip where the digital layer is stacked on the sensor and the analog layers [V. Re et al., Nuc. Instr. and Meth. in Phys. Res. A, doi:10.1016/j.nima.2010.05.039]. In the presented work, we consider a data-push architecture designed for a sensor matrix of an area of about 1.3 cm 2 with a pitch of 50 microns. The readout circuit tries to take great advantage of the high density of in-pixel digital logic allowed by vertical integration. We aim at sustaining a rate density of 100 Mtrack ṡ s -1 ṡ cm -2 with a temporal resolution below 1 μs. We show how this architecture can cope with these stressing conditions presenting the results of Monte Carlo simulations.

  16. Estimation of proportions in mixed pixels through their region characterization

    NASA Technical Reports Server (NTRS)

    Chittineni, C. B. (Principal Investigator)

    1981-01-01

    A region of mixed pixels can be characterized through the probability density function of proportions of classes in the pixels. Using information from the spectral vectors of a given set of pixels from the mixed pixel region, expressions are developed for obtaining the maximum likelihood estimates of the parameters of probability density functions of proportions. The proportions of classes in the mixed pixels can then be estimated. If the mixed pixels contain objects of two classes, the computation can be reduced by transforming the spectral vectors using a transformation matrix that simultaneously diagonalizes the covariance matrices of the two classes. If the proportions of the classes of a set of mixed pixels from the region are given, then expressions are developed for obtaining the estmates of the parameters of the probability density function of the proportions of mixed pixels. Development of these expressions is based on the criterion of the minimum sum of squares of errors. Experimental results from the processing of remotely sensed agricultural multispectral imagery data are presented.

  17. Synchrotron beam test with a photon-counting pixel detector.

    PubMed

    Brönnimann, C; Florin, S; Lindner, M; Schmitt, B; Schulze-Briese, C

    2000-09-01

    Synchrotron beam measurements were performed with a single-photon-counting pixel detector to investigate the influence of threshold settings on charge sharing. Improvement of image homogeneity by adjusting the threshold of each pixel individually was demonstrated. With a flat-field correction, the homogeneity could be improved. A measurement of the point spread function is reported. PMID:16609212

  18. Novel integrated CMOS pixel structures for vertex detectors

    SciTech Connect

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

    2003-10-29

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

  19. CMOS Active-Pixel Image Sensor With Simple Floating Gates

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.

    1996-01-01

    Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.

  20. Rectangular pixels for efficient color image sampling

    NASA Astrophysics Data System (ADS)

    Singh, Tripurari; Singh, Mritunjay

    2011-01-01

    We present CFA designs that faithfully capture images with specified luminance and chrominance bandwidths. Previous academic research has mostly been concerned with maximizing PSNR of reconstructed images without regard to chrominance bandwidth and cross-talk. Commercial systems, on the other hand, pay close attention to both these parameters as well as to the visual quality of reconstructed images. They commonly sacrifice resolution by using a sufficiently aggressive OLPF to achieve low cross-talk and artifact free images. In this paper, we present the so called Chrominance Bandwidth Ratio, r, model in an attempt to capture both the chrominance bandwidth and the cross-talk between the various signals. Next, we examine the effect of tuning photosite aspect ratio, a hitherto neglected design parameter, and show the benefit of setting it at a different value than the pixel aspect ratio of the display. We derive panchromatic CFA patterns that provably minimize the photo-site count for all values of r. An interesting outcome is a CFA design that captures full chrominance bandwidth, yet uses fewer photosites than the venerable color-stripe design. Another interesting outcome is a low cost practical CFA design that captures chrominance at half the resolution of luminance using only 4 unique filter colors, that lends itself to efficient linear demosaicking, and yet vastly outperforms the Bayer CFA with identical number of photosites demosaicked with state of the art compute-intensive nonlinear algorithms.

  1. CMB component separation in the pixel domain

    NASA Astrophysics Data System (ADS)

    Doroshkevich, A.; Verkhodanov, O.

    2011-02-01

    We show that the popular internal linear combination approach is unstable with respect to division of the observed map pixels to a set of “homogeneous” subsamples. For various choices of such subsamples we can obtain a restored CMB signal with amplitudes ranging from zero to the amplitude of the observed signal. We propose an approach which allows us to obtain corrected estimates of the CMB power spectrum Cℓ at ℓ≤30 and provides results similar to WMAP for larger ℓ. Using this approach, we eliminate some anomalies of the WMAP results. In particular, our estimate of the quadrupole is consistent with the theoretically expected one. The effect of the “axis of evil” is suppressed, and the symmetry of the north and south galactic hemispheres increases. These results can change estimates of quadrupole polarization and the redshift of reionization of the Universe. We also propose a new simple approach which can improve the WMAP estimates of the high ℓ power spectrum.

  2. Singlet mega-pixel resolution lens

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

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

  3. Research on ionospheric tomography based on variable pixel height

    NASA Astrophysics Data System (ADS)

    Zheng, Dunyong; Li, Peiqing; He, Jie; Hu, Wusheng; Li, Chaokui

    2016-05-01

    A novel ionospheric tomography technique based on variable pixel height was developed for the tomographic reconstruction of the ionospheric electron density distribution. The method considers the height of each pixel as an unknown variable, which is retrieved during the inversion process together with the electron density values. In contrast to conventional computerized ionospheric tomography (CIT), which parameterizes the model with a fixed pixel height, the variable-pixel-height computerized ionospheric tomography (VHCIT) model applies a disturbance to the height of each pixel. In comparison with conventional CIT models, the VHCIT technique achieved superior results in a numerical simulation. A careful validation of the reliability and superiority of VHCIT was performed. According to the results of the statistical analysis of the average root mean square errors, the proposed model offers an improvement by 15% compared with conventional CIT models.

  4. Attenuating Stereo Pixel-Locking via Affine Window Adaptation

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  5. Using an Active Pixel Sensor In A Vertex Detector

    SciTech Connect

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

    2004-04-22

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

  6. DC-DC powering for the CMS pixel upgrade

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  7. Operational experience with the ATLAS Pixel Detector at the LHC

    NASA Astrophysics Data System (ADS)

    Lapoire, C.; Atlas Collaboration

    2013-01-01

    The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as B-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures and detector performance. The detector performance is excellent: 96.2% of the pixels are operational, noise occupancy is sufficiently low and hit efficiency exceed the design specification.

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

    SciTech Connect

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

    2007-12-21

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

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

    NASA Astrophysics Data System (ADS)

    Kwan, Simon; Lei, CM; Menasce, Dario; Moroni, Luigi; Ngadiuba, Jennifer; Prosser, Alan; Rivera, Ryan; Terzo, Stefano; Turqueti, Marcos; Uplegger, Lorenzo; Vigani, Luigi; Dinardo, Mauro E.

    2016-03-01

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

  10. Hybridization process for back-illuminated silicon Geiger-mode avalanche photodiode arrays

    NASA Astrophysics Data System (ADS)

    Schuette, Daniel R.; Westhoff, Richard C.; Loomis, Andrew H.; Young, Douglas J.; Ciampi, Joseph S.; Aull, Brian F.; Reich, Robert K.

    2010-04-01

    We present a unique hybridization process that permits high-performance back-illuminated silicon Geiger-mode avalanche photodiodes (GM-APDs) to be bonded to custom CMOS readout integrated circuits (ROICs) - a hybridization approach that enables independent optimization of the GM-APD arrays and the ROICs. The process includes oxide bonding of silicon GM-APD arrays to a transparent support substrate followed by indium bump bonding of this layer to a signal-processing ROIC. This hybrid detector approach can be used to fabricate imagers with high-fill-factor pixels and enhanced quantum efficiency in the near infrared as well as large-pixel-count, small-pixel-pitch arrays with pixel-level signal processing. In addition, the oxide bonding is compatible with high-temperature processing steps that can be used to lower dark current and improve optical response in the ultraviolet.

  11. Analysis of Multipath Pixels in SAR Images

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  12. Flare Hybrids

    NASA Astrophysics Data System (ADS)

    Tomczak, M.; Dubieniecki, P.

    2015-12-01

    On the basis of the Solar Maximum Mission observations, Švestka ( Solar Phys. 121, 399, 1989) introduced a new class of flares, the so-called flare hybrids. When they start, they look like typical compact flares (phase 1), but later on, they look like flares with arcades of magnetic loops (phase 2). We summarize the characteristic features of flare hybrids in soft and hard X-rays as well as in the extreme ultraviolet; these features allow us to distinguish flare hybrids from other flares. In this article, additional energy release or long plasma cooling timescales are suggested as possible causes of phase 2. We estimate the frequency of flare hybrids, and study the magnetic configurations favorable for flare hybrid occurrence. Flare hybrids appear to be quite frequent, and the difference between the lengths of magnetic loops in the two interacting loop systems seem to be a crucial parameter for determining their characteristics.

  13. Development of a simplified simulation model for performance characterization of a pixellated CdZnTe multimodality imaging system.

    PubMed

    Guerra, P; Santos, A; Darambara, D G

    2008-02-21

    Current requirements of molecular imaging lead to the complete integration of complementary modalities in a single hybrid imaging system to correlate function and structure. Among the various existing detector technologies, which can be implemented to integrate nuclear modalities (PET and/or single-photon emission computed tomography with x-rays (CT) and most probably with MR, pixellated wide bandgap room temperature semiconductor detectors, such as CdZnTe and/or CdTe, are promising candidates. This paper deals with the development of a simplified simulation model for pixellated semiconductor radiation detectors, as a first step towards the performance characterization of a multimodality imaging system based on CdZnTe. In particular, this work presents a simple computational model, based on a 1D approximate solution of the Schockley-Ramo theorem, and its integration into the Geant4 application for tomographic emission (GATE) platform in order to perform accurately and, therefore, improve the simulations of pixellated detectors in different configurations with a simultaneous cathode and anode pixel readout. The model presented here is successfully validated against an existing detailed finite element simulator, the multi-geometry simulation code, with respect to the charge induced at the anode, taking into consideration interpixel charge sharing and crosstalk, and to the detector charge induction efficiency. As a final point, the model provides estimated energy spectra and time resolution for (57)Co and (18)F sources obtained with the GATE code after the incorporation of the proposed model. PMID:18263961

  14. Simulation of digital pixel readout chip architectures with the RD53 SystemVerilog-UVM verification environment using Monte Carlo physics data

    NASA Astrophysics Data System (ADS)

    Conti, E.; Marconi, S.; Christiansen, J.; Placidi, P.; Hemperek, T.

    2016-01-01

    The simulation and verification framework developed by the RD53 collaboration is a powerful tool for global architecture optimization and design verification of next generation hybrid pixel readout chips. In this paper the framework is used for studying digital pixel chip architectures at behavioral level. This is carried out by simulating a dedicated, highly parameterized pixel chip description, which makes it possible to investigate different grouping strategies between pixels and different latency buffering and arbitration schemes. The pixel hit information used as simulation input can be either generated internally in the framework or imported from external Monte Carlo detector simulation data. The latter have been provided by both the CMS and ATLAS experiments, featuring HL-LHC operating conditions and the specifications related to the Phase 2 upgrade. Pixel regions and double columns were simulated using such Monte Carlo data as inputs: the performance of different latency buffering architectures was compared and the compliance of different link speeds with the expected column data rate was verified.

  15. Monolithic pixel detectors in silicon on insulator technology

    NASA Astrophysics Data System (ADS)

    Bisello, Dario

    2013-05-01

    Silicon On Insulator (SOI) is becoming an attractive technology to fabricate monolithic pixel detectors. The possibility of using the depleted resistive substrate as a drift collection volume and to connect it by means of vias through the buried oxide to the pixel electronic makes this kind of approach interesting both for particle and photon detection. In this paper I report the results obtained in the development of monolithic pixel detectors in an SOI technology by a collaboration between groups from the University and INFN of Padova (Italy) and the LBNL and the SCIPP at UCSC (USA).

  16. Active-Pixel Image Sensors With Programmable Resolution

    NASA Technical Reports Server (NTRS)

    Kemeny, Sabrina E.; Fossum, Eric R.; Pain, Bedabrata; Nakamura, Junichi; Matthies, Larry H.

    1996-01-01

    Active-pixel image sensors with programmable resolution proposed for use in applications in which speed and efficiency of processing of image data enhanced by providing those data at varying resolutions. Such applications include modeling of biological vision, stereoscopic range-finding, recognition of patterns, tracking targets, and progressive transmission of compressed images. In target-tracking application, sensor initially forms low-resolution image from which area of interest identified, then sensor set at high resolution for examination of identified area. Outputs of contiguous pixels combined. Sensor of this type made to act as though it comprised fewer and larger pixels.

  17. Vertically integrated pixel readout chip for high energy physics

    SciTech Connect

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

    2011-01-01

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

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

    SciTech Connect

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

    2010-10-01

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

  19. Characterization of a Depleted Monolithic Active Pixel Sensor (DMAPS) prototype

    NASA Astrophysics Data System (ADS)

    Obermann, T.; Havranek, M.; Hemperek, T.; Hügging, F.; Kishishita, T.; Krüger, H.; Marinas, C.; Wermes, N.

    2015-03-01

    New monolithic pixel detectors integrating CMOS electronics and sensor on the same silicon substrate are currently explored for particle tracking in future HEP experiments, most notably at the LHC . The innovative concept of Depleted Monolithic Active Pixel Sensors (DMAPS) is based on high resistive silicon bulk material enabling full substrate depletion and the application of an electrical drift field for fast charge collection, while retaining full CMOS capability for the electronics. The technology (150 nm) used offers quadruple wells and allows to implement the pixel electronics with independently isolated N- and PMOS transistors. Results of initial studies on the charge collection and sensor performance are presented.

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  1. Modulation transfer function measurement technique for small-pixel detectors

    NASA Technical Reports Server (NTRS)

    Marchywka, Mike; Socker, Dennis G.

    1992-01-01

    A modulation transfer function (MTF) measurement technique suitable for large-format, small-pixel detector characterization has been investigated. A volume interference grating is used as a test image instead of the bar or sine wave target images normally used. This technique permits a high-contrast, large-area, sinusoidal intensity distribution to illuminate the device being tested, avoiding the need to deconvolve raw data with imaging system characteristics. A high-confidence MTF result at spatial frequencies near 200 cycles/mm is obtained. We present results at several visible light wavelengths with a 6.8-micron-pixel CCD. Pixel response functions are derived from the MTF results.

  2. Consequences of Mixed Pixels on Temperature Emissivity Separation

    SciTech Connect

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

    2007-02-01

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

  3. Sub-pixel radiometry: a three-part study in generating synthetic imagery that incorporates sub-pixel variation

    NASA Astrophysics Data System (ADS)

    Paul, Sarah; Goodenough, Adam A.; Brown, Scott D.; Salvaggio, Carl

    2010-04-01

    A pixel represents the limit of spatial knowledge that can be represented in an image. It is represented as a single (perhaps spectral) digital count value that represents the energy propagating from a spatial portion of a scene. In any captured image, that single value is the result of many factors including the composition of scene optical properties within the projected pixel, the characteristic point spread function (or, equivalently, modulation transfer function) of the system, and the sensitivity of the detector element itself. This presentation examines the importance of sub-pixel variability in the context of generating synthetic imagery for remote sensing applications. The study was performed using the Digital Imaging and Remote Sensing Image Generation (DIRSIG) tool, an established ray-tracing based synthetic modeling system whose approach to sub-pixel computations was updated during this study. The paper examines three aspects of sub-pixel variability of interest to the remote sensing community. The first study simply looks at sampling frequency relative to structural frequency in a scene and the effects of aliasing on an image. The second considers the task of modeling a sub-pixel target whose signature would be mixed with background clutter, such as a small, hot target in a thermal image. The final study looks at capturing the inherent spectral variation in a single class of material, such as grass in hyperspectral imagery. Through each study we demonstrate in a quantitative fashion, the improved capabilities of DIRSIG's sub-pixel rendering algorithms.

  4. Development and control of kilo-pixel MEMS deformable mirrors and spatial light modulators

    NASA Astrophysics Data System (ADS)

    Perreault, Julie Ann

    This dissertation describes the development of kilo-pixel micro-electro-mechanical optical-quality surface-micromachined deformable mirrors and spatial light modulators along with scalable control electronics. These silicon-based deformable mirrors have the potential to modulate spatial and temporal features of an optical wavefront with applications in imaging, beam-forming, and optical communication systems. Techniques to improve the manufacturing, quality, and capability of these mirrors are detailed. The new mirror system was characterized and a scalable control system was developed to coordinate and control a large array of mirrors. Three types of kilo-pixel deformable mirrors were created: continuous membrane, segmented membrane, and a hybrid stress-relieved membrane mirrors. This new class of mirrors, deformed using electrostatically actuated surface-normal actuators, have an aperature of 10 mm, a stroke of 2 mum, position repeatability of 3 nm, surface roughness of 12 nm, reflectivity of 91%, and a bandwidth in air of 7 kHz. A custom fabrication process was developed in tandem with a new mirror design to address design and layout issues including packaging, residual stress, reliability, yield, fill factor, and surface topography. A chemo-mechanical polishing process improved the surface quality of the mirrors by decreasing surface roughness from an RMS value of 46nm to 12nm. A gold coating process increased reflectivity from 42% to greater than 91% without introducing a significant amount of stress in the mirror membrane. An alternative actuator design and layout was also developed that achieved an increased stroke of 6 mum, with the potential for even longer stroke with stress reduction. The long stroke capability was realized through introduction of split electrodes, actuation membrane cuts, and a double stacked anchor architecture. A computer-driven electronic system was developed to aid in the electro-mechanical testing of these deformable mirrors. Quasi

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

  6. Active pixel sensors with substantially planarized color filtering elements

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  7. Coherence experiments in single-pixel digital holography.

    PubMed

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

    2015-05-15

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

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

    SciTech Connect

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

    1996-07-01

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

  9. ARCONS: a 1024 pixel superconducting integral field spectrograph

    NASA Astrophysics Data System (ADS)

    O'Brien, Kieran; Mazin, Ben; McHugh, Sean; Meeker, Seth; Marsden, Danica; Bumble, Bruce

    2012-09-01

    ARCONS, the Array Camera for Optical to Near-infrared Spectrophotometry, was recently commissioned at the Coude focus of the 200-inch Hale Telescope at the Palomar Observatory. At the heart of this unique instrument is a 1024-pixel Microwave Kinetic Inductance Detector (MKID), exploiting the Kinetic Inductance effect to measure the energy of the incoming photon to better than several percent. The ground-breaking instrument is lens coupled with a pixel scale of 0.23"/pixel, with each pixel recording the arrival time (< 2 _μsec) and energy of a photon (~10%) in the optical to near-IR (0.4-1.1 microns) range. The scientific objectives of the instrument include the rapid follow-up and classi_cation of the transient phenomena

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

    NASA Astrophysics Data System (ADS)

    Stramaglia, Maria Elena

    2016-07-01

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

  11. Detection systems for mass spectrometry imaging: a perspective on novel developments with a focus on active pixel detectors.

    PubMed

    Jungmann, Julia H; Heeren, Ron M A

    2013-01-15

    Instrumental developments for imaging and individual particle detection for biomolecular mass spectrometry (imaging) and fundamental atomic and molecular physics studies are reviewed. Ion-counting detectors, array detection systems and high mass detectors for mass spectrometry (imaging) are treated. State-of-the-art detection systems for multi-dimensional ion, electron and photon detection are highlighted. Their application and performance in three different imaging modes--integrated, selected and spectral image detection--are described. Electro-optical and microchannel-plate-based systems are contrasted. The analytical capabilities of solid-state pixel detectors--both charge coupled device (CCD) and complementary metal oxide semiconductor (CMOS) chips--are introduced. The Medipix/Timepix detector family is described as an example of a CMOS hybrid active pixel sensor. Alternative imaging methods for particle detection and their potential for future applications are investigated. PMID:23239313

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

  13. MTF study of planar small pixel pitch quantum IR detectors

    NASA Astrophysics Data System (ADS)

    Gravrand, O.; Baier, N.; Ferron, A.; Rochette, F.; Berthoz, J.; Rubaldo, L.; Cluzel, R.

    2014-06-01

    The actual trend in quantum IR detector development is the design of very small pixel pitch large arrays. From previously 30μm pitch, the standard pixel pitch is today 15μm and is expected to decrease to 12μm in the next few years. Furthermore, focal plane arrays (FPA) with pixel pitch as small as small as 10μm has been demonstrated. Such ultra-small pixel pitches are very small compared to the typical length ruling the electrical characteristics of the absorbing materials, namely the minority carrier diffusion length. As an example for low doped N type HgCdTe or InSb material, this diffusion length is of the order of 30 to 50μm, i.e. 3 to 5 times the targeted pixel pitches. This has strong consequences on the modulation transfer function (MTF) for planar structures, where the lateral extension of the photodiode is limited by diffusion. For such aspect ratios, the self-confinement of neighboring diodes may not be efficient enough to maintain optimal MTF. Therefore, this issue has to be addressed in order to take full benefits of the pixel pitch reduction in terms of image resolution. This paper aims at investigating the MTF evolution of HgCdTe and InSb FPAs decreasing the pixel pitch below 15μm. Both experimental measurements and finite element simulations are used to discuss this issue. Different scenarii will be compared, namely deep mesa etch between pixels, internal drift, surface recombination, thin absorbing layers.

  14. FPIX2, the BTeV pixel readout chip

    SciTech Connect

    David C. Christian et al.

    2003-12-10

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

  15. Pixel readout electronics for LHC and biomedical applications

    NASA Astrophysics Data System (ADS)

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

    2000-01-01

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

  16. A Chip and Pixel Qualification Methodology on Imaging Sensors

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  17. Application-specific architectures of CMOS monolithic active pixel sensors

    NASA Astrophysics Data System (ADS)

    Szelezniak, Michal; Besson, Auguste; Claus, Gilles; Colledani, Claude; Degerli, Yavuz; Deptuch, Grzegorz; Deveaux, Michael; Dorokhov, Andrei; Dulinski, Wojciech; Fourches, Nicolas; Goffe, Mathieu; Grandjean, Damien; Guilloux, Fabrice; Heini, Sebastien; Himmi, Abdelkader; Hu, Christine; Jaaskelainen, Kimmo; Li, Yan; Lutz, Pierre; Orsini, Fabienne; Pellicioli, Michel; Shabetai, Alexandre; Valin, Isabelle; Winter, Marc

    2006-11-01

    Several development directions intended to adapt and optimize monolithic active pixel sensors for specific applications are presented in this work. The first example, compatible with the STAR microvertex upgrade, is based on a simple two-transistor pixel circuitry. It is suited for a long integration time, room-temperature operation and minimum power dissipation. In another approach for this application, a specific readout method is proposed, allowing optimization of the integration time independently of the full frame-readout time. The circuit consists of an in-pixel front-end voltage amplifier, with a gain on the order of five, followed by two analog memory cells. The extended version of this scheme, based on the implementation of more memory cells per pixel, is the solution considered for the outer layers of a microvertex detector at the international linear collider. For the two innermost layers, a circuit allowing fast frame scans together with on-line, on-chip data sparsification is proposed. The first results of this prototype demonstrate that the fixed pattern dispersion is reduced below a noise level of 15 e -, allowing the use of a single comparator or a low-resolution ADC per pixel column. A common element for most of the mentioned readout schemes is a low-noise, low power consumption, layout efficient in-pixel amplifier. A review of possible solutions for this element together with some experimental results is presented.

  18. Accelerating sub-pixel marker segmentation using GPU

    NASA Astrophysics Data System (ADS)

    Handel, Holger

    2009-02-01

    Sub-pixel accurate marker segmentation is an important task for many computer vision systems. The 3D-positions of markers are used in control loops to determine the position of machine tools or robot end-effectors. Accurate segmentation of the marker position in the image plane is crucial for accurate reconstruction. Many subpixel segmentation algorithms are computationally intensive, especially when the number of markers increases. Modern graphics hardware with its massively parallel architecture provides a powerful tool for many image segmentation tasks. Especially, the time consuming sub-pixel refinement steps in marker segmentation can benefit from the recent progress. This article presents an implementation of a sub-pixel marker segmentation framework using the GPU to accelerate the processing time. The image segmentation chain consists of two stages. The first is a pre-processing stage which segments the initial position of the marker with pixel accuracy, the second stage refines the initial marker position to sub-pixel accuracy. Both stages are implemented as shader programs on the GPU. The flexible architecture allows it to combine different pre-processing and sub-pixel refinement algorithms. Experimental results show that significant speed-up can be achieved compared to CPU implementations, especially when the number of markers increases.

  19. High Chromaticity Aluminum Plasmonic Pixels for Active Liquid Crystal Displays.

    PubMed

    Olson, Jana; Manjavacas, Alejandro; Basu, Tiyash; Huang, Da; Schlather, Andrea E; Zheng, Bob; Halas, Naomi J; Nordlander, Peter; Link, Stephan

    2016-01-26

    Chromatic devices such as flat panel displays could, in principle, be substantially improved by incorporating aluminum plasmonic nanostructures instead of conventional chromophores that are susceptible to photobleaching. In nanostructure form, aluminum is capable of producing colors that span the visible region of the spectrum while contributing exceptional robustness, low cost, and streamlined manufacturability compatible with semiconductor manufacturing technology. However, individual aluminum nanostructures alone lack the vivid chromaticity of currently available chromophores because of the strong damping of the aluminum plasmon resonance in the visible region of the spectrum. In recent work, we showed that pixels formed by periodic arrays of Al nanostructures yield far more vivid coloration than the individual nanostructures. This progress was achieved by exploiting far-field diffractive coupling, which significantly suppresses the scattering response on the long-wavelength side of plasmonic pixel resonances. In the present work, we show that by utilizing another collective coupling effect, Fano interference, it is possible to substantially narrow the short-wavelength side of the pixel spectral response. Together, these two complementary effects provide unprecedented control of plasmonic pixel spectral line shape, resulting in aluminum pixels with far more vivid, monochromatic coloration across the entire RGB color gamut than previously attainable. We further demonstrate that pixels designed in this manner can be used directly as switchable elements in liquid crystal displays and determine the minimum and optimal numbers of nanorods required in an array to achieve good color quality and intensity. PMID:26639191

  20. Active Pixel Sensor Characterization for the STAR Detector

    NASA Astrophysics Data System (ADS)

    King, Jake

    2004-10-01

    The STAR collaboration is studying matter at high temperatures and densities. If a significant improvement to the measurement of particle trajectories can be made, charmed mesons that decay away from the primary collision point could be identified. To achieve this goal, STAR is building a vertex detector consisting of a new technology Â- active pixel sensors. (APS) An APS is an implementation of standard CMOS technology in which each pixel has a photodiode directly above the epitaxial layer. Incident particles produce electron-hole pairs in the epitaxial layer, and these electrons accumulate on the photodiode. Charge from the photodiode is digitized to identify the position of the incident particle. It is important to characterize the signal to noise, readout time, and resolution on several different pixel sizes so that the vertex detector can be optimized for cost and speed. Larger pixels result in a faster data acquisition, while smaller pixels have better resolution. We will present studies of 5, 10, 20 and 30μm square pixel geometries that measure charge distribution and collection. We will also display the results of using a field emission scanning electron microscope with energies from 1 to 30 keV. This tool has the potential to probe regions of the APS integrated circuit and contribute to understanding its properties.

  1. High-voltage pixel sensors for ATLAS upgrade

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

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

    PubMed Central

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

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-06-01

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

  4. Intrinsic pixel size variation in an LSST prototype sensor

    NASA Astrophysics Data System (ADS)

    Baumer, M. A.; Roodman, A.

    2015-05-01

    The ambitious science goals of the Large Synoptic Survey Telescope (LSST) have motivated a search for new and unexpected sources of systematic error in the LSST camera. Flat field images are a rich source of data on sensor anomalies, although such effects are typically dwarfed by shot noise in a single flat field. After combining many (0~50) such images into 'ultraflats' to reduce the impact of shot noise, we perform photon transfer analysis on a pixel-by-pixel basis and observe no spatial structure in pixel linearity or gain at light levels of 100 ke- and below. At 125 ke-, a columnar structure is observed in the gain map—we attribute this to a flux-dependent charge-transfer inefficiency. We also probe small-scale variations in effective pixel size by analyzing pixel-neighbor correlations in ultraflat images, where we observe clear evidence of intrinsic variation in effective pixel size in an LSST prototype sensor near the ~ .3% level.

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  8. Study on 512×128 pixels InGaAs near infrared focal plane arrays

    NASA Astrophysics Data System (ADS)

    Li, Xue; Tang, Hengjing; Huang, Songlei; Shao, Xiumei; Li, Tao; Huang, Zhangcheng; Gong, Haimei

    2014-10-01

    It is well known that In0.53Ga0.47As epitaxial material is lattice-matched to InP substrate corresponding to the wavelength from 0.9μm to 1.7μm, which results to high quality material and good device characteristics at room temperature. In order to develop the near infrared multi-spectral imaging, 512×128 pixels InGaAs Near Infrared Focal Plane Arrays (FPAs) were studied. The n-InP/i-InGaAs/n-InP double hereto-structure epitaxial material was grown by MBE. The 512×128 back-illuminated planar InGaAs detector arrays were fabricated, including the improvement of passivation film, by grooving the diffusion masking layer, the P type electrode layer, In bump condition and so on. The photo-sensitive region has the diffusion area of 23×23μm2 and pixel pitch of 30×30μm2 . The 512×128 detector arrays were individually hybridized on readout integrated circuit(ROIC) by Indium bump based on flip-chip process to make focal plane arrays (FPAs). The ROIC is based on a capacitive trans-impedance amplifier with correlated double sampling and integrated while readout (IWR) mode with high readout velocity of every pixel resulting in low readout noise and high frame frequency. The average peak detectivity and the response non-uniformity of the FPAs are 1.63×1012 cmHz1/2/W and 5.9%, respectively. The power dissipation and frame frequency of the FPAs are about 180mW and 400Hz, respectively.

  9. Development of an Indium bump bond process for silicon pixel detectors at PSI

    NASA Astrophysics Data System (ADS)

    Broennimann, Ch.; Glaus, F.; Gobrecht, J.; Heising, S.; Horisberger, M.; Horisberger, R.; Kästli, H. C.; Lehmann, J.; Rohe, T.; Streuli, S.

    2006-09-01

    The hybrid pixel detectors used in the high-energy physics experiments currently under construction use a vertical connection technique, the so-called bump bonding. As the pitch below 100 μm, required in these applications, cannot be fulfilled with standard industrial processes (e.g. the IBM C4 process), an in-house bump bond process using reflowed indium bumps was developed at PSI as part of the R&D for the CMS-pixel detector. The bump deposition on the sensor is performed in two subsequent lift-off steps. As the first photolithographic step a thin under bump metalization (UBM) is sputtered onto bump pads. It is wettable by indium and defines the diameter of the bump. The indium is evaporated via a second photolithographic step with larger openings and is reflowed afterwards. The height of the balls is defined by the volume of the indium. On the readout chip only one photolithographic step is carried out to deposit the UBM and a thin indium layer for better adhesion. After mating both parts a second reflow is performed for self-alignment and obtaining high mechanical strength. For the placement of the chips a manual and an automatic machine were constructed. The former is very flexible in handling different chip and module geometries but has a limited throughput while the latter features a much higher grade of automatization and is therefore much more suited for producing hundreds of modules with a well-defined geometry. The reliability of this process was proven by the successful construction of the PILATUS detector. The construction of PILATUS 6M (60 modules) and the CMS pixel barrel (roughly 800 modules) has started in early 2006.

  10. Improved Design of Active Pixel CMOS Sensors for Charged Particle Detection

    SciTech Connect

    Deptuch, Grzegorz

    2007-11-12

    The Department of Energy (DOE) nuclear physics program requires developments in detector instrumentation electronics with improved energy, position and timing resolution, sensitivity, rate capability, stability, dynamic range, and background suppression. The current Phase-I project was focused on analysis of standard-CMOS photogate Active Pixel Sensors (APS) as an efficient solution to this challenge. The advantages of the CMOS APS over traditional hybrid approaches (i.e., separate detection regions bump-bonded to readout circuits) include greatly reduced cost, low power and the potential for vastly larger pixel counts and densities. However, challenges remain in terms of the signal-to-noise ratio (SNR) and readout speed (currently on the order of milliseconds), which is the major problem for this technology. Recent work has shown that the long readout time for photogate APS is due to the presence of (interface) traps at the semiconductor-oxide interface. This Phase-I work yielded useful results in two areas: (a) Advanced three-dimensional (3D) physics-based simulation models and simulation-based analysis of the impact of interface trap density on the transient charge collection characteristics of existing APS structures; and (b) Preliminary analysis of the feasibility of an improved photogate pixel structure (i.e., new APS design) with an induced electric field under the charge collecting electrode to enhance charge collection. Significant effort was dedicated in Phase-I to the critical task of implementing accurate interface trap models in CFDRC's NanoTCAD 3D semiconductor device-physics simulator. This resulted in validation of the new NanoTCAD models and simulation results against experimental (published) data, within the margin of uncertainty associated with obtaining device geometry, material properties, and experimentation details. Analyses of the new, proposed photogate APS design demonstrated several promising trends.

  11. First look at the beam test results of the FPIX2 readout chip for the BTeV silicon pixel detector

    SciTech Connect

    Uplegger, L.; Appel, J.A.; Artuso, M.; Cardoso, G.; Cease, H.P.; Chiodini, G.; Christian, D.C.; Cinabro, D.A.; Coluccia, R.; Hoff, J.; Kwan, S.; Magni, S.; Mekkaoui, A.; Menasce, D.; Newsom, C.; Papavassiliou, V.; Schreiner, A.; Turqueti, M.A.; Yarema, R.; Wang, J.C.; /Fermilab /Syracuse U. /INFN, Lecce /Wayne State U. /INFN, Milan /Iowa U. /New Mexico State U.

    2004-11-01

    High energy and nuclear physics experiments need tracking devices with excellent spatial precision and readout speed in the face of ever-higher track densities and increased radiation environments. The new generation of hybrid pixel detectors (arrays of silicon diodes bump bonded to arrays of front-end electronic cells) is a technology able to meet these challenges. We report the first results of the BTeV silicon pixel detector beam test carried out at Fermilab in summer 2004. Tests were performed using a 120 GeV/c proton beam incident on a 6 planes pixel detector telescope. The last prototype developed for the BTeV experiment (FPIX2) is tested in the middle of the telescope. There is no external trigger and events were built using the time-stamp information provided by the readout chips.

  12. Pixel-to-pixel correspondence alignment method of a 2CCD camera by using absolute phase map

    NASA Astrophysics Data System (ADS)

    Huang, Shujun; Liu, Yue; Bai, Xuefei; Wang, Zhangying; Zhang, Zonghua

    2015-06-01

    An alignment method of a 2CCD camera to build pixel-to-pixel correspondence between the infrared (IR) CCD sensor and the visible CCD sensor by using the absolute phase data is presented. Vertical and horizontal sinusoidal fringe patterns are generated by software and displayed on a liquid crystal display screen. The displayed fringe patterns are captured simultaneously by the IR sensor and the visible sensor of the 2CCD camera. The absolute phase values of each pixel at IR and visible channels are calculated from the captured fringe pattern images by using Fourier transform and the optimum three-fringe number selection method. The accurate pixel corresponding relationship between the two sensors can be determined along the vertical and the horizontal directions by comparing the obtained absolute phase data in IR and visible channels. Experimental results show the high accuracy, effectiveness, and validity of the proposed 2CCD alignment method. By using the continuous absolute phase information, this method can determine the pixel-to-pixel correspondence with high resolution.

  13. Verification of Dosimetry Measurements with Timepix Pixel Detectors for Space Applications

    NASA Technical Reports Server (NTRS)

    Kroupa, M.; Pinsky, L. S.; Idarraga-Munoz, J.; Hoang, S. M.; Semones, E.; Bahadori, A.; Stoffle, N.; Rios, R.; Vykydal, Z.; Jakubek, J.; Pospisil, S.; Turecek, D.; Kitamura, H.

    2014-01-01

    The current capabilities of modern pixel-detector technology has provided the possibility to design a new generation of radiation monitors. Timepix detectors are semiconductor pixel detectors based on a hybrid configuration. As such, the read-out chip can be used with different types and thicknesses of sensors. For space radiation dosimetry applications, Timepix devices with 300 and 500 microns thick silicon sensors have been used by a collaboration between NASA and University of Houston to explore their performance. For that purpose, an extensive evaluation of the response of Timepix for such applications has been performed. Timepix-based devices were tested in many different environments both at ground-based accelerator facilities such as HIMAC (Heavy Ion Medical Accelerator in Chiba, Japan), and at NSRL (NASA Space Radiation Laboratory at Brookhaven National Laboratory in Upton, NY), as well as in space on board of the International Space Station (ISS). These tests have included a wide range of the particle types and energies, from protons through iron nuclei. The results have been compared both with other devices and theoretical values. This effort has demonstrated that Timepix-based detectors are exceptionally capable at providing accurate dosimetry measurements in this application as verified by the confirming correspondence with the other accepted techniques.

  14. Smart pixel imaging with computational-imaging arrays

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  15. Stellarator hybrids

    SciTech Connect

    Furth, H.P.; Ludescher, C.

    1984-08-01

    The present paper briefly reviews the subject of tokamak-stellarator and pinch-stellarator hybrids, and points to two interesting new possibilities: compact-torus-stellarators and mirror-stellarators.

  16. Gas pixel detectors for X-ray polarimetry applications

    NASA Astrophysics Data System (ADS)

    Bellazzini, R.; Angelini, F.; Baldini, L.; Bitti, F.; Brez, A.; Cavalca, F.; Del Prete, M.; Kuss, M.; Latronico, L.; Omodei, N.; Pinchera, M.; Massai, M. M.; Minuti, M.; Razzano, M.; Sgro, C.; Spandre, G.; Tenze, A.; Costa, E.; Soffitta, P.

    2006-05-01

    We discuss a new class of micro pattern gas detectors, the gas pixel detector (GPD), in which a complete integration between the gas amplification structure and the read-out electronics has been reached. An application-specific integrated circuit (ASIC) built in deep sub-micron technology has been developed to realize a monolithic device that is, at the same time, the pixelized charge collecting electrode and the amplifying, shaping and charge measuring front-end electronics. The CMOS chip has the top metal layer patterned in a matrix of 80 μm pitch hexagonal pixels, each of them directly connected to the underneath electronics chain which has been realized in the remaining five layers of the 0.35 μm VLSI technology. Results from tests of a first prototype of such detector with 2 k pixels and a full scale version with 22 k pixels are presented. The application of this device for Astronomical X-ray Polarimetry is discussed. The experimental detector response to polarized and unpolarized X-ray radiation is shown. Results from a full MonteCarlo simulation for two astronomical sources, the Crab Nebula and the Hercules X1, are also reported.

  17. Super pixel density based clustering automatic image classification method

    NASA Astrophysics Data System (ADS)

    Xu, Mingxing; Zhang, Chuan; Zhang, Tianxu

    2015-12-01

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

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

    PubMed

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

    2016-02-01

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

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

    SciTech Connect

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

    1993-08-01

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

  20. Operational experience with the ATLAS Pixel detector at the LHC

    NASA Astrophysics Data System (ADS)

    Deluca, C.

    2011-12-01

    The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of pico-seconds lifetime particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97.5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, and a good alignment allows high quality track resolution.

  1. Visual mining business service using pixel bar charts

    NASA Astrophysics Data System (ADS)

    Hao, Ming C.; Dayal, Umeshwar; Casati, Fabio

    2004-06-01

    Basic bar charts have been commonly available, but they only show highly aggregated data. Finding the valuable information hidden in the data is essential to the success of business. We describe a new visualization technique called pixel bar charts, which are derived from regular bar charts. The basic idea of a pixel bar chart is to present all data values directly instead of aggregating them into a few data values. Pixel bar charts provide data distribution and exceptions besides aggregated data. The approach is to represent each data item (e.g. a business transaction) by a single pixel in the bar chart. The attribute of each data item is encoded into the pixel color and can be accessed and drilled down to the detail information as needed. Different color mappings are used to represent multiple attributes. This technique has been prototyped in three business service applications-Business Operation Analysis, Sales Analysis, and Service Level Agreement Analysis at Hewlett Packard Laboratories. Our applications show the wide applicability and usefulness of this new idea.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  3. A 25μm pitch LWIR focal plane array with pixel-level 15-bit ADC providing high well capacity and targeting 2mK NETD

    NASA Astrophysics Data System (ADS)

    Guellec, Fabrice; Peizerat, Arnaud; Tchagaspanian, Michael; de Borniol, Eric; Bisotto, Sylvette; Mollard, Laurent; Castelein, Pierre; Zanatta, Jean-Paul; Maillart, Patrick; Zecri, Michel; Peyrard, Jean-Christophe

    2010-04-01

    CEA Leti has recently developed a new readout IC (ROIC) with pixel-level ADC for cooled infrared focal plane arrays (FPAs). It operates at 50Hz frame rate in a snapshot Integrate-While-Read (IWR) mode. It targets applications that provide a large amount of integrated charge thanks to a long integration time. The pixel-level analog-to-digital conversion is based on charge packets counting. This technique offers a large well capacity that paves the way for a breakthrough in NETD performances. The 15 bits ADC resolution preserves the excellent detector SNR at full well (3Ge-). These characteristics are essential for LWIR FPAs as broad intra-scene dynamic range imaging requires high sensitivity. The ROIC, featuring a 320x256 array with 25μm pixel pitch, has been designed in a standard 0.18μm CMOS technology. The main design challenges for this digital pixel array (SNR, power consumption and layout density) are discussed. The IC has been hybridized to a LWIR detector fabricated using our in-house HgCdTe process. The first electro-optical test results of the detector dewar assembly are presented. They validate both the pixel-level ADC concept and its circuit implementation. Finally, the benefit of this LWIR FPA in terms of NETD performance is demonstrated.

  4. Optics and cryogenics for the 1.1 THz multi-pixel heterodyne receiver for APEX

    NASA Astrophysics Data System (ADS)

    Hurtado, Norma; Graf, Urs U.; Adams, Henning; Honingh, C. E.; Jacobs, Karl; Pütz, Patrick; Güsten, Rolf; Stutzki, Jürgen

    2014-08-01

    The 1.1 THz multi-pixel heterodyne receiver will be mounted in the Nasmyth A cabin of the 12 m APEX telescope on the Chajnantor plateau, 5000 meters altitude in northern Chile. The receiver will cover the spectral window of 1000 - 1080 GHz, where important spectral lines like CO 9-8 at 1036.9 GHz, a tracer of warm and dense gas and OH+ at 1033 GHz and NH+ at 1012.6 GHz, both important for the study of chemical networks in the ISM, are located. The multi-pixel receiver greatly enhances the science output under the difficult observing conditions in this frequency range. Two 9-pixel focal plane sub-arrays on orthogonal polarizations are installed in easily removable cartridges. We developed a new thermal link to connect the cartridges to the cryostat. Our thermal link is an all-metal design: aluminum and Invar. All the optics is fully reflective, thus avoiding the absorption and reflection losses of dielectric lenses and reducing standing waves in the receiver. To guaranty internal optics alignment, we employ a monolithic integrated optics approach for the cold optics and the Focal Plane Unit (FPU) optics modeled after the CHARM (Compact Heterodyne Array Receiver Module) concept. The receiver uses synthesizer-driven solid-state local oscillators (LO) and the mixers will be balanced SIS mixers, which are essentially based on the design of the on-chip balanced SIS mixers at 490 GHz developed in our institute. Singleended HEB mixers are used for the laboratory tests of the optics. The LO power distribution is accommodated behind the FPU optics. It is composed of the LO optics, which includes a collimating Fourier grating, and an LO distribution plate to supply LO signal to each of the 9 pixels of the sub-array. Different options for the LO coupling design and fabrication are being analyzed and will be based on in-house hybrid waveguide/planar technology. We summarize the receiver project with emphasis on the cryogenics and the optics and present laboratory test results

  5. Virus based Full Colour Pixels using a Microheater

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  6. Wire Bond Encapsulation for the CMS Forward Pixel Upgrade

    NASA Astrophysics Data System (ADS)

    Higginbotham, Sam; CMS Collaboration

    2015-04-01

    The Phase 1 upgrade of the pixel tracker for the CMS experiment will require the assembly of approximately 1000 modules consisting of pixel sensors bump bonded to readout chips. Electrical connections between the custom readout chips and support ASIC's that constitute the front-end of the pixel data acquisition system are made via wire bonds to a thin printed circuit board. Part of the assembly process carried out at Purdue University includes the partial encapsulation of the wire bonds for mechanical protection, prevention of electrolytic corrosion, and to damp oscillations due to Lorentz forces from transient current pulses in large magnetic fields. We present the details of the robotic assembly process which allows the deposition of the viscous encapsulant compound with 100 micron precision.

  7. Modulation transfer function measurement technique for small-pixel detectors.

    PubMed

    Marchywka, M; Socker, D G

    1992-12-01

    A modulation transfer function (MTF) measurement technique suitable for large-format, small-pixel detector characterization has been investigated. A volume interference grating is used as a test image instead of the bar or sine wave target images normally used. This technique permits a high-contrast, large-area, sinusoidal intensity distribution to illuminate the device being tested, avoiding the need to deconvolve raw data with imaging system characteristics. A high-confidence MTF result at spatial frequencies near 200 cycles/mm is obtained. We present results at several visible light wavelengths with a 6.8-microm-pixel CCD. Pixel response functions are derived from the MTF results. PMID:20802584

  8. Virus based Full Colour Pixels using a Microheater.

    PubMed

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

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

  10. Velocity map imaging using an in-vacuum pixel detector

    NASA Astrophysics Data System (ADS)

    Gademann, Georg; Huismans, Ymkje; Gijsbertsen, Arjan; Jungmann, Julia; Visschers, Jan; Vrakking, Marc J. J.

    2009-10-01

    The use of a new type in-vacuum pixel detector in velocity map imaging (VMI) is introduced. The Medipix2 and Timepix semiconductor pixel detectors (256×256 square pixels, 55×55 μm2) are well suited for charged particle detection. They offer high resolution, low noise, and high quantum efficiency. The Medipix2 chip allows double energy discrimination by offering a low and a high energy threshold. The Timepix detector allows to record the incidence time of a particle with a temporal resolution of 10 ns and a dynamic range of 160 μs. Results of the first time application of the Medipix2 detector to VMI are presented, investigating the quantum efficiency as well as the possibility to operate at increased background pressure in the vacuum chamber.

  11. Calibration analysis software for the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Stramaglia, Maria Elena

    2016-07-01

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

  12. Visual mining geo-related data using pixel bar charts

    NASA Astrophysics Data System (ADS)

    Hao, Ming C.; Keim, Daniel A.; Dayal, Umeshwar; Wright, Peter; Schneidewind, Joern

    2005-03-01

    A common approach to analyze geo-related data is using bar charts or x-y plots. They are intuitive and easy to use. But important information often gets lost. In this paper, we introduce a new interactive visualization technique called Geo Pixel Bar Charts, which combines the advantages of Pixel Bar Charts and interactive maps. This technique allows analysts to visualize large amounts of spatial data without aggregation and shows the geographical regions corresponding to the spatial data attribute at the same time. In this paper, we apply Geo Pixel Bar Charts to visually mining sales transactions and Internet usage from different locations. Our experimental results show the effectiveness of this technique for providing data distribution and exceptions from the map.

  13. Virus based Full Colour Pixels using a Microheater

    PubMed Central

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

    2015-01-01

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

  14. The Speedster-EXD- A New Event-Driven Hybrid CMOS X-ray Detector

    NASA Astrophysics Data System (ADS)

    Griffith, Christopher V.; Falcone, Abraham D.; Prieskorn, Zachary R.; Burrows, David N.

    2016-01-01

    The Speedster-EXD is a new 64×64 pixel, 40-μm pixel pitch, 100-μm depletion depth hybrid CMOS x-ray detector with the capability of reading out only those pixels containing event charge, thus enabling fast effective frame rates. A global charge threshold can be specified, and pixels containing charge above this threshold are flagged and read out. The Speedster detector has also been designed with other advanced in-pixel features to improve performance, including a low-noise, high-gain capacitive transimpedance amplifier that eliminates interpixel capacitance crosstalk (IPC), and in-pixel correlated double sampling subtraction to reduce reset noise. We measure the best energy resolution on the Speedster-EXD detector to be 206 eV (3.5%) at 5.89 keV and 172 eV (10.0%) at 1.49 keV. The average IPC to the four adjacent pixels is measured to be 0.25%±0.2% (i.e., consistent with zero). The pixel-to-pixel gain variation is measured to be 0.80%±0.03%, and a Monte Carlo simulation is applied to better characterize the contributions to the energy resolution.

  15. Classification of multispectral image data by the Binary Diamond neural network and by nonparametric, pixel-by-pixel methods

    NASA Technical Reports Server (NTRS)

    Salu, Yehuda; Tilton, James

    1993-01-01

    The classification of multispectral image data obtained from satellites has become an important tool for generating ground cover maps. This study deals with the application of nonparametric pixel-by-pixel classification methods in the classification of pixels, based on their multispectral data. A new neural network, the Binary Diamond, is introduced, and its performance is compared with a nearest neighbor algorithm and a back-propagation network. The Binary Diamond is a multilayer, feed-forward neural network, which learns from examples in unsupervised, 'one-shot' mode. It recruits its neurons according to the actual training set, as it learns. The comparisons of the algorithms were done by using a realistic data base, consisting of approximately 90,000 Landsat 4 Thematic Mapper pixels. The Binary Diamond and the nearest neighbor performances were close, with some advantages to the Binary Diamond. The performance of the back-propagation network lagged behind. An efficient nearest neighbor algorithm, the binned nearest neighbor, is described. Ways for improving the performances, such as merging categories, and analyzing nonboundary pixels, are addressed and evaluated.

  16. Pixel Detectors For Diffraction Experiments At The Swiss Light Source

    SciTech Connect

    Huelsen, G.; Eikenberry, E.F.; Schmitt, B.; Schulze-Briese, C.; Tomizaki, T.; Stampanoni, M.; Willmott, P.; Patterson, B.; Broennimann, Ch.; Horisberger, R.; Toyokawa, H.; Borchert, G. L.

    2004-05-12

    The PILATUS detector (Pixel Apparatus for the SLS) is a large, quantum-limited area X-ray detector for protein crystallography which is currently under construction. Its basic units are modules with 16 CMOS chips bump-bonded to a large, continuously sensitive silicon sensor with 157x366 pixels of 217x217 {mu}m2, leading to an active area of 34x80 mm2. With a counting circuit in each pixel, X-rays are detected in single photon counting mode, leading to excellent, noise-free data. The main properties of the detector are an energy range of 6 to 30 keV, no back-ground due to leakage current or readout-noise, fast read-out time of 6.7 ms, a rate/pixel >104/s and a PSF of one pixel. PILATUS detectors are installed at the SLS X06SA protein crystallography beamline, and at both the surface diffraction (SD) station and the radiography and tomography (XTM) station of beamline X04SA. The detectors are operated at room temperature and thus are very easy to use. Experiments benefit from the ability to detect very weak diffraction spots with high precision. At the SD station and at the XTM station, which is equipped with a Bragg magnifier, diffraction, radiography and tomography experiments showed promising results. At beamline X06SA, a three-module array (1120x157 pixels) with a readout time of 6.7 ms was tested. This system was used to collect fine phi-sliced protein crystal data in continuous sample rotation mode in which the crystal was continuously rotated with a slow angular velocity of 0.04 deg./s without any shutter operation. Exposure time per frame ranged from 100 ms to a few seconds, depending on the crystal. These initial experiments show the potential of this method.

  17. Mapping Pixel Windows To Vectors For Parallel Processing

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.

    1996-01-01

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

  18. Highly Reflective Multi-stable Electrofluidic Display Pixels

    NASA Astrophysics Data System (ADS)

    Yang, Shu

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

  19. The BTeV pixel detector and trigger system

    SciTech Connect

    Simon Kwan

    2002-12-03

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

  20. Modelling Gaia CCD pixels with Silvaco 3D engineering software

    NASA Astrophysics Data System (ADS)

    Seabroke, G. M.; Prod'Homme, T.; Hopkinson, G.; Burt, D.; Robbins, M.; Holland, A.

    2011-02-01

    Gaia will only achieve its unprecedented measurement accuracy requirements with detailed calibration and correction for radiation damage. We present our Silvaco 3D engineering software model of the Gaia CCD pixel and two of its applications for Gaia: (1) physically interpreting supplementary buried channel (SBC) capacity measurements (pocket-pumping and first pixel response) in terms of e2v manufacturing doping alignment tolerances; and (2) deriving electron densities within a charge packet as a function of the number of constituent electrons and 3D position within the charge packet as input to microscopic models being developed to simulate radiation damage.

  1. CMOS VLSI Active-Pixel Sensor for Tracking

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

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

    SciTech Connect

    Guilherme Cardoso et al.

    2003-11-05

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

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

    SciTech Connect

    Sergio Zimmermann et al.

    2001-09-11

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

  4. The BTeV pixel and microstrip detector

    SciTech Connect

    Simon W Kwan

    2003-06-04

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

  5. High Voltage Dielectrophoretic and Magnetophoretic Hybrid Integrated Circuit / Microfluidic Chip

    PubMed Central

    Issadore, David; Franke, Thomas; Brown, Keith A.; Hunt, Thomas P.; Westervelt, Robert M.

    2010-01-01

    A hybrid integrated circuit (IC) / microfluidic chip is presented that independently and simultaneously traps and moves microscopic objects suspended in fluid using both electric and magnetic fields. This hybrid chip controls the location of dielectric objects, such as living cells and drops of fluid, on a 60 × 61 array of pixels that are 30 × 38 μm2 in size, each of which can be individually addressed with a 50 V peak-to-peak, DC to 10 MHz radio frequency voltage. These high voltage pixels produce electric fields above the chip’s surface with a magnitude , resulting in strong dielectrophoresis (DEP) forces . Underneath the array of DEP pixels there is a magnetic matrix that consists of two perpendicular sets of 60 metal wires running across the chip. Each wire can be sourced with 120 mA to trap and move magnetically susceptible objects using magnetophoresis (MP). The DEP pixel array and magnetic matrix can be used simultaneously to apply forces to microscopic objects, such as living cells or lipid vesicles, that are tagged with magnetic nanoparticles. The capabilities of the hybrid IC / microfluidic chip demonstrated in this paper provide important building blocks for a platform for biological and chemical applications. PMID:20625468

  6. A 65 nm pixel readout ASIC with quick transverse momentum discrimination capabilities for the CMS Tracker at HL-LHC

    NASA Astrophysics Data System (ADS)

    Ceresa, D.; Kaplon, J.; Francisco, R.; Caratelli, A.; Kloukinas, K.; Marchioro, A.

    2016-01-01

    A readout ASIC for the hybrid pixel detector with the capability of performing quick recognition of particles with high transverse momentum has been designed for the requirements of the CMS Outer Tracker at the High Luminosity LHC . The particle momentum dicrimination capability represents the main challenge for this design together with the low power requirement: the constraint of low mass for the new tracker dictates a total power budget of less than 100 mW/cm2. The choice of a 65 nm CMOS technology has made it possible to satisfy this power requirement despite the fairly large amount of logic necessary to perform the momentum discrimination and the continuous operation at 40 MHz. Several techniques for low power have been used to implement this logic that performs cluster reduction, position offset correction and coordinate encoding. A prototype chip including a large part of the final functionality and the full front-end has been realized and comprises a matrix of 16 by 3 rectangular pixels of 100 μm × 1446 μm, providing 7.65 mm2 of segmented active area. Measurements of the analog front-end characteristics closely match the simulations and confirm the consumption of < 30 μA per pixel. Front-end characterization and irradiation results up to 150 MRad are also reported.

  7. 1024 × 1024 Format pixel co-located simultaneously readable dual-band QWIP focal plane

    NASA Astrophysics Data System (ADS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Mumolo, J. M.; Ting, D. Z.; Hill, C. J.; Nguyen, J.; Simolon, B.; Woolaway, J.; Wang, S. C.; Li, W.; LeVan, P. D.; Tidrow, M. Z.

    2009-11-01

    This paper reports the first demonstration of the megapixel-simultaneously-readable and pixel-co-registered dual-band quantum well infrared photodetector (QWIP) focal plane array (FPA). The dual-band QWIP device was developed by stacking two multi-quantum-well stacks tuned to absorb two different infrared wavelengths. The full width at half maximum (FWHM) of the mid-wave infrared (MWIR) band extends from 4.4 to 5.1 μm and the FWHM of a long-wave infrared (LWIR) band extends from 7.8 to 8.8 μm. Dual-band QWIP detector arrays were hybridized with custom fabricated direct injection read out integrated circuits (ROICs) using the indium bump hybridization technique. The initial dual-band megapixel QWIP FPAs were cooled to 70 K operating temperature. The preliminary data taken from the first megapixel QWIP FPA has shown system NEΔT of 27 and 40 mK for MWIR and LWIR bands, respectively.

  8. Impact of defective pixels in AMLCDs on the perception of medical images

    NASA Astrophysics Data System (ADS)

    Kimpe, Tom; Sneyders, Yuri

    2006-03-01

    With LCD displays, each pixel has its own individual transistor that controls the transmittance of that pixel. Occasionally, these individual transistors will short or alternatively malfunction, resulting in a defective pixel that always shows the same brightness. With ever increasing resolution of displays the number of defect pixels per display increases accordingly. State of the art processes are capable of producing displays with no more than one faulty transistor out of 3 million. A five Mega Pixel medical LCD panel contains 15 million individual sub pixels (3 sub pixels per pixel), each having an individual transistor. This means that a five Mega Pixel display on average will have 5 failing pixels. This paper investigates the visibility of defective pixels and analyzes the possible impact of defective pixels on the perception of medical images. JND simulations were done to study the effect of defective pixels on medical images. Our results indicate that defective LCD pixels can mask subtle features in medical images in an unexpectedly broad area around the defect and therefore may reduce the quality of diagnosis for specific high-demanding areas such as mammography. As a second contribution an innovative solution is proposed. A specialized image processing algorithm can make defective pixels completely invisible and moreover can also recover the information of the defect so that the radiologist perceives the medical image correctly. This correction algorithm has been validated with both JND simulations and psycho visual tests.

  9. Modelling and 3D optimisation of CdTe pixels detector array geometry - Extension to small pixels

    NASA Astrophysics Data System (ADS)

    Zumbiehl, A.; Hage-Ali, M.; Fougeres, P.; Koebel, J. M.; Regal, R.; Rit, C.; Ayoub, M.; Siffert, P.

    2001-08-01

    CdTe and CdZnTe pixel detectors offer great interest for many applications, especially for medical and industrial imaging. Up to now, the material, generally, used and investigated for pixel arrays was CZT (Hamel et al., IEEE Trans. Nucl. Sci. 43 (3) (1996) 1422; Barrett et al., Phys. Rev. Lett. 75 (1) (1995) 156; Bennett et al., Nucl. Instr. and Meth. A 392 (1997) 260; Eskin et al., J. Appl. Phys. 85 (2) (1999) 647; Brunett et al., J. Appl. Phys. 86 (7) (1999) 3926; Luke, Nucl. Instr. and Meth. A 380 (1996) 232), but cadmium telluride can also be an appropriate choice, as shown here. However, we clearly demonstrate here that the optimal pixel configuration is highly dependent on the electrical transport properties of the material. Depending on the field of primary interest, either energy resolution or counting rate efficiency in the photopeak, the geometry for each case has to be optimised. For that purpose, we have developed a calculation of the signal induced onto the pixel. Two distinct parts are used: after showing our approach for the weighting potential calculation, we present our results performed by a "pseudo-Monte Carlo" simulation. Results are supported by a few experimental comparisons. We argue about the optimum sizes with clarifying the problems caused by too small and too large pixel sizes. The study field is chosen to be vast, i.e. pixel size to detector thickness ratios ( W/ L) of 1/8-1, and detector thickness of 1.0-8.0 mm. In addition, several electrical transport properties are used. Since efficiency is often of primary interest, thick detectors could be very attractive, which are shown to be really feasible even on CdTe.

  10. Hard x-ray phase contrast imaging using single absorption grating and hybrid semiconductor pixel detector.

    PubMed

    Krejci, Frantisek; Jakubek, Jan; Kroupa, Martin

    2010-11-01

    A method for x-ray phase contrast imaging is introduced in which only one absorption grating and a microfocus x-ray source in a tabletop setup are used. The method is based on precise subpixel position determination of the x-ray pattern projected by the grating directly from the pattern image. For retrieval of the phase gradient and absorption image (both images obtained from one exposure), it is necessary to measure only one projection of the investigated object. Thus, our method is greatly simplified compared with the phase-stepping method and our method can significantly reduce the time-consuming scanning and possibly the unnecessary dose. Furthermore, the technique works with a fully polychromatic spectrum and gives ample variability in object magnification. Consequently, the approach can open the way to further widespread application of phase contrast imaging, e.g., into clinical practice. The experimental results on a simple testing object as well as on complex biological samples are presented. PMID:21133473

  11. Pixelated Single-crystal Diamond Detector for fast neutron measurements

    NASA Astrophysics Data System (ADS)

    Rebai, M.; Cazzaniga, C.; Croci, G.; Tardocchi, M.; Perelli Cippo, E.; Calvani, P.; Girolami, M.; Trucchi, D. M.; Grosso, G.; Gorini, G.

    2015-03-01

    Single-crystal Diamond Detectors (SDDs), due to their high radiation hardness, fast response time and small size, are good candidates as fast neutron detectors in those environments where the high neutron flux is an issue, such as spallation neutron sources and the next generation thermonuclear fusion plasmas, i.e. the ITER experiment. Neutron detection in SDDs is based on the collection of electron-hole pairs produced by charged particles generated by neutron interactions with 12C. Recent measurements have demonstrated the SDD capability of measuring the neutron flux with a good energy resolution and at high rates. In this work a novel detector based on a 12-pixels SDD matrix will be presented. Each pixel is equipped with an independent electronic chain: the fast shaping preamplifier coupled to a digitizer is able to combine the high rate capability and the good energy resolution. Two CAEN digitizers are compared and the possibility of performing good energy resolution measurements (<2%) and at high rates (>1 MHz per channel) is described. Each pixel was characterized and calibrated using an 241Am source: the energy resolution was evaluated and gives a mean value of 1.73% at 5.5 MeV. The good energy resolution achieved and its uniformity between pixels are the demonstration of the capability of this novel detector as a spectrometer. This system will be installed during the next Deuterium-Tritium campaign on a collimated vertical line of sight at JET for 14 MeV neutron measurements.

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

    NASA Technical Reports Server (NTRS)

    Mooney, James T.

    2005-01-01

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

  13. 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.

  14. Precision tracking with a single gaseous pixel detector

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  17. Use of silicon pixel detectors in double electron capture experiments

    NASA Astrophysics Data System (ADS)

    Cermak, P.; Stekl, I.; Shitov, Yu A.; Mamedov, F.; Rukhadze, E. N.; Jose, J. M.; Cermak, J.; Rukhadze, N. I.; Brudanin, V. B.; Loaiza, P.

    2011-01-01

    A novel experimental approach to search for double electron capture (EC/EC) is discussed in this article. R&D for a new generation EC/EC spectrometer based on silicon pixel detectors (SPDs) has been conducted since 2009 for an upgrade of the TGV experiment. SPDs built on Timepix technology with a spectroscopic readout from each individual pixel are an effective tool to detect the 2νEC/EC signature of the two low energy X-rays hitting two separate pixels. The ability of SPDs to indentify α/β/γ particles and localize them precisely leads to effective background discrimination and thus considerable improvement of the signal-to-background ratio (S/B). A multi-SPD system, called a Silicon Pixel Telescope (SPT), is planned based on the experimental approach of the TGV calorimeter which measures thin foils of enriched EC/EC-isotope sandwiched between HPGe detectors working in coincidence mode. The sources of SPD internal background have been identified by measuring SPD radiopurity with a low-background HPGe detector as well as by long-term SPD background runs in the Modane underground laboratory (LSM, France), and results of these studies are presented.

  18. Thin Film on CMOS Active Pixel Sensor for Space Applications

    PubMed Central

    Schulze Spuentrup, Jan Dirk; Burghartz, Joachim N.; Graf, Heinz-Gerd; Harendt, Christine; Hutter, Franz; Nicke, Markus; Schmidt, Uwe; Schubert, Markus; Sterzel, Juergen

    2008-01-01

    A 664 × 664 element Active Pixel image Sensor (APS) with integrated analog signal processing, full frame synchronous shutter and random access for applications in star sensors is presented and discussed. A thick vertical diode array in Thin Film on CMOS (TFC) technology is explored to achieve radiation hardness and maximum fill factor.

  19. Influence of TFT-LCD pixel structure on holographic representation

    NASA Astrophysics Data System (ADS)

    Wang, Hongjun; Wang, Zhao; Tian, Ailing; Liu, Bingcai

    2008-09-01

    As a new holographic display device, TFT-LCD (Thin Film Transistor Liquid Crystal Displays) is key technical component of holographic representation for easy controlled by computer. With the development of exquisite processing technology, that it instead of the traditional holographic plate become historical necessity and would be the development direction of holographic optics. Based on principles of holography and display character of LCD, the property which the LCD was used as a holographic plate was analyzed. The emphasis on discuss influence of LCD black matrix on holographic representation. First, analyzed on LCD pixel structure, the LCD pixel structure mathematical model was established. LCD was character representation by pixel structure parameters. Then, the influence of LCD pixels structure on holographic representation was analyzed by computer simulation. Meanwhile, the SONY LCX023 was chosen for holographic plate, the He-Ne laser which the wavelength is 0.6328um was holographic representation light source. The holographic representation system was established for test influence of LCD on holographic representation. Final, compared between computer simulations and optical experimental results, the mathematical model of LCD was proved to be true. When aperture ratio is 0.625, the holographic representation wouldn't be distinguished between representation images. At the same time, some useful results was acquired for improve application effects of LCD in holographic representation.

  20. High responsivity CMOS imager pixel implemented in SOI technology

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  1. Optimization of Focusing by Strip and Pixel Arrays

    SciTech Connect

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

    2005-06-30

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

  2. Metamaterial-based single pixel imaging system (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Padilla, Willie; Watts, Claire M.; Nadell, Christian; Montoya, John A.; Krishna, Sanjay

    2015-09-01

    Single pixel cameras are useful imaging devices where it is difficult or infeasible to fashion focal plan arrays. For example in the Far Infrared (FIR) it is difficult to perform imaging by conventional detector arrays, owing to the cost and size of such an array. The typical single pixel camera uses a spatial light modulator (SLM) - placed in the conjugate image plane - and is used to sample various portions of the image. The spatially modulated light emerging from the SLM is then sent to a single detector where the light is condensed with suitable optics for detection. Conventional SLMs are either based on liquid crystals or digital mirror devices. As such these devices are limited in modulation speeds of order 30 kHz. Further there is little control over the type of light that is modulated. We present metamaterial based spatial light modulators which provide the ability to digitally encode images - with various measurement matrix coefficients - thus permitting high speed and fidelity imaging capability. In particular we use the Hadamard matrix and related S-matrix to encode images for single pixel imaging. Metamaterials thus permit imaging in regimes of the electromagnetic spectrum where conventional SLMs are not available. Additionally, metamaterials offer several salient features that are not available with commercial SLMs. For example, metamaterials may be used to enable hyperspectral, polarimetric, and phase sensitive imaging. We present the theory and experimental results of single pixel imaging with digital metamaterials in the far infrared and highlight the future of this exciting field.

  3. Spectral Information Retrieval for Sub-Pixel Building Edge Detection

    NASA Astrophysics Data System (ADS)

    Avbelj, J.

    2012-07-01

    Building extraction from imagery has been an active research area for decades. However, the precise building detection from hyperspectral (HSI) images solely is a less often addressed research question due to the low spatial resolution of data. The building boundaries are usually represented by spectrally mixed pixels, and classical edge detector algorithms fail to detect borders with sufficient completeness. The idea of the proposed method is to use fraction of materials in mixed pixels to derive weights for adjusting building boundaries. The building regions are detected using seeded region growing and merging in a HSI image; for the initial seed point selection the digital surface model (DSM) is used. Prior to region growing, the seeds are statistically tested for outliers on the basis of their spectral characteristics. Then, the border pixels of building regions are compared in spectrum to the seed points by calculating spectral dissimilarity. From this spectral dissimilarity the weights for weighted and constrained least squares (LS) adjustment are derived. We used the Spectral Angle Mapper (SAM) for spectral similarity measure, but the proposed boundary estimation method could benefit from soft classification or spectral unmixing results. The method was tested on a HSI image with spatial resolution of 4 m, and buildings of rectangular shape. The importance of constraints to the relations between building parts, e.g. perpendicularity is shown on example with a building with inner yards. The adjusted building boundaries are compared to the laser DSM, and have a relative accuracy of boundaries 1/4 of a pixel.

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

    DOE PAGESBeta

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

    2016-03-01

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

  5. Design of a reconfigurable optical microprocessor for smart pixel applications

    NASA Astrophysics Data System (ADS)

    Vagheeswar, V. S.; Krishna Kumar, Shankar Raman; Chokhani, Arvind; Beyette, Fred R., Jr.

    2003-12-01

    The ever increasing demand for communication bandwidth and system interconnectivity has been a motivating factor behind the integration of optoelectronics device and conventional data processing circuitry. Over the last two decades, fiber optic components have become the dominant technology in the telecommunications industry. In last 5 years, optical interconnection techniques have been suggested as a solution to the interconnect density and bandwidth problems faced by electrical systems at the cabinet, PC-board and even chip level. Based on the smart pixel architectures in the last decade, the proposed chip monolithically integrates optical sensors with silicon CMOS based circuitry. This project incorporates an instruction fetch unit (IFU), that fetches the instructions from an external host computer, and a 2D-array of one-bit smart pixels called the processing element (PE). Each PE consists of an ALU, control logic, dual port register memory bank, photoreceiver circuit and associated driver circuits. By tiling these smart pixels in 2D, it is possible to form a programmable smart pixel array that is well suited to read optical page-oriented data types. The CASPR chip contains a 4x4 array of PEs connected to a single IFU. Inter PE communication has been established through nearest neighbor communication. Simultaneous communication to all the PEs is possible through global communication. The instruction set for this architecture is 17-bit long. The chip has been successfully fabricated in 0.5´ technology. We present in this paper the design and initial test results from the recent fabrication.

  6. Sub-pixel localization of highways in AVIRIS images

    NASA Technical Reports Server (NTRS)

    Salu, Yehuda

    1995-01-01

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

  7. Commissioning and Alignment of the Pixel Luminosity Telescope of CMS

    NASA Astrophysics Data System (ADS)

    Riley, Grant; CMS Collaboration

    2015-04-01

    The Pixel Luminosity Telescope (PLT) is one of the newest additions to the CMS detector at the LHC. It consists of 16 3-layer telescopes of silicon pixel detectors pointing toward the interaction point at the center of CMS. The pixel detectors are based on the same technology as the silicon pixel detector of CMS. The chips have an additional output, called a fast-out. This fast-out is sent whenever a hit is detected, and will be used to measure the luminosity. The fast-out can also be used to self trigger the the PLT allowing for measurement of the systematics and beam backgrounds. The PLT is expected to significantly improve the precision of the luminosity measurement that is fundamental for particle searches and cross section measurements with the CMS detector. Furthermore, with reconstructed particle trajectories, measurements of beam backgrounds and the location of the interaction point centroid can be obtained. First experiences with the PLT detector before and after installation are presented and the track reconstruction is discussed.

  8. Overview of the BTeV Pixel Detector

    SciTech Connect

    Jeffrey A Appel

    2002-12-10

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2003-03-01

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

  14. Autofluorescence correction for fluorescence in situ hybridization

    SciTech Connect

    Szoelloesi, J.; Balazs, M.; Waldman, F.C.

    1995-08-01

    Optimal sensitivity of fluorescence in situ hybridization (FISH) requires bright signals and low background fluorescence. Use of locus-specific probes is especially dependent on high sensitivity. Some tissue preparations show high autofluorescence, masking small or dim signals. We have developed a new method for subtracting autofluorescence from digital images on a pixel-by-pixel basis. It is based on the observation that fluorescent labels for FISH have narrower excitation and emission spectra than the chemical components responsible for autofluorescence. Our new approach uses calculation of the ratio of autofluorescence between multiple color images for correction of autofluorescence in each individual image. By subtracting autofluorescence components, we were able to enhance centromeric signals and make previously indistiguishable cosmid signals clearly visible. This image-processing approach to autofluorescence correction may widen the applicability of gene-specific probes in FISH analysis of tumor material. 15 refs., 3 fig., 1 tab.

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

    PubMed

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

    2012-06-20

    In this paper we propose a hardware architecture for high-speed computer-generated hologram generation that significantly reduces the number of memory access times to avoid the bottleneck in the memory access operation. For this, we use three main schemes. The first is pixel-by-pixel calculation, rather than light source-by-source calculation. The second is a parallel calculation scheme extracted by modifying the previous recursive calculation scheme. The last scheme is a fully pipelined calculation scheme and exactly structured timing scheduling, achieved by adjusting the hardware. The proposed hardware is structured to calculate a row of a computer-generated hologram in parallel and each hologram pixel in a row is calculated independently. It consists of and input interface, an initial parameter calculator, hologram pixel calculators, a line buffer, and a memory controller. The implemented hardware to calculate a row of a 1920×1080 computer-generated hologram in parallel uses 168,960 lookup tables, 153,944 registers, and 19,212 digital signal processing blocks in an Altera field programmable gate array environment. It can stably operate at 198 MHz. Because of three schemes, external memory bandwidth is reduced to approximately 1/20,000 of the previous ones at the same calculation speed. PMID:22722274

  16. Test of DEP hybrid photodiodes

    SciTech Connect

    Baumbaugh, A.; Binkley, M.; Elias, J.

    1997-08-01

    The goal of the measurement was to study some parameters of DEP HYBRID PHOTODIODES (HPD), and the check its performance for CMS calorimetry at LHC. The principal of the HPD operation is described. The schematic view of the HPD. The HPD is vacuum photo device composed of photocathode (PC) and a silicon PIN diode (Si) as multiplication system in a very close proximity geometry. The distance between PC and Si is of the order of several mm and has an electric field < 10 kV. The photoelectron emited by the photocathode multiply by a factor of several thousand in the silicon and the charge is collected on the HPD`s anode. Several types of HPD`s were tested. There was a single channel HPD, called {open_quotes}E-type{close_quotes} with p-side of the silicon facing the HPD`s photocathode and two multipixel HPD (DEP) namely a 25 pixel HPD and a 7 pixel HPD. Both were of {open_quotes}T-type{close_quotes} structure with n-side of silicon facing the photocathode.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Kading, Benjamin; Straub, Jeremy

    2015-05-01

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

  19. Sub-pixel image classification for forest types in East Texas

    NASA Astrophysics Data System (ADS)

    Westbrook, Joey

    Sub-pixel classification is the extraction of information about the proportion of individual materials of interest within a pixel. Landcover classification at the sub-pixel scale provides more discrimination than traditional per-pixel multispectral classifiers for pixels where the material of interest is mixed with other materials. It allows for the un-mixing of pixels to show the proportion of each material of interest. The materials of interest for this study are pine, hardwood, mixed forest and non-forest. The goal of this project was to perform a sub-pixel classification, which allows a pixel to have multiple labels, and compare the result to a traditional supervised classification, which allows a pixel to have only one label. The satellite image used was a Landsat 5 Thematic Mapper (TM) scene of the Stephen F. Austin Experimental Forest in Nacogdoches County, Texas and the four cover type classes are pine, hardwood, mixed forest and non-forest. Once classified, a multi-layer raster datasets was created that comprised four raster layers where each layer showed the percentage of that cover type within the pixel area. Percentage cover type maps were then produced and the accuracy of each was assessed using a fuzzy error matrix for the sub-pixel classifications, and the results were compared to the supervised classification in which a traditional error matrix was used. The overall accuracy of the sub-pixel classification using the aerial photo for both training and reference data had the highest (65% overall) out of the three sub-pixel classifications. This was understandable because the analyst can visually observe the cover types actually on the ground for training data and reference data, whereas using the FIA (Forest Inventory and Analysis) plot data, the analyst must assume that an entire pixel contains the exact percentage of a cover type found in a plot. An increase in accuracy was found after reclassifying each sub-pixel classification from nine classes

  20. New SOFRADIR 10μm pixel pitch infrared products

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  1. Using Trained Pixel Classifiers to Select Images of Interest

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  2. Compressive sensing spectroscopy with a single pixel camera.

    PubMed

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

    2016-07-01

    Spectrometry requires high spectral resolution and high photometric precision while also balancing cost and complexity. We address these requirements by employing a compressive-sensing camera capable of improving signal acquisition speed and sensitivity in limited signal scenarios. In particular, we implement a fast single pixel spectrophotometer with no moving parts and measure absorption and emission spectra comparable with commercial products. Our method utilizes Hadamard matrices to sample the spectra and then minimizes the total variation of the signal. The experimental setup includes standard optics and a grating, a low-cost digital micromirror device, and an intensity detector. The resulting spectrometer produces a 512 pixel spectrum with low mean-squared error and up to a 90% reduction in data acquisition time when compared with a standard spectrophotometer. PMID:27409210

  3. Sensor Development and Readout Prototyping for the STAR Pixel Detector

    SciTech Connect

    Greiner, L.; Anderssen, E.; Matis, H.S.; Ritter, H.G.; Stezelberger, T.; Szelezniak, M.; Sun, X.; Vu, C.; Wieman, H.

    2009-01-14

    The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) is designing a new vertex detector. The purpose of this upgrade detector is to provide high resolution pointing to allow for the direct topological reconstruction of heavy flavor decays such as the D{sup 0} by finding vertices displaced from the collision vertex by greater than 60 microns. We are using Monolithic Active Pixel Sensor (MAPS) as the sensor technology and have a coupled sensor development and readout system plan that leads to a final detector with a <200 {micro}s integration time, 400 M pixels and a coverage of -1 < {eta} < 1. We present our coupled sensor and readout development plan and the status of the prototyping work that has been accomplished.

  4. Sub-pixel resolution with the Multispectral Thermal Imager (MTI).

    SciTech Connect

    Decker, Max Louis; Smith, Jody Lynn; Nandy, Prabal

    2003-06-01

    The Multispectral Thermal Imager Satellite (MTI) has been used to test a sub-pixel sampling technique in an effort to obtain higher spatial frequency imagery than that of its original design. The MTI instrument is of particular interest because of its infrared detectors. In this spectral region, the detector size is traditionally the limiting factor in determining the satellite's ground sampling distance (GSD). Additionally, many over-sampling techniques require flexible command and control of the sensor and spacecraft. The MTI sensor is well suited for this task, as it is the only imaging system on the MTI satellite bus. In this super-sampling technique, MTI is maneuvered such that the data are collected at sub-pixel intervals on the ground. The data are then processed using a deconvolution algorithm using in-scene measured point spread functions (PSF) to produce an image with synthetically-boosted GSD.

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1995-05-01

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

  7. Digital pixel sensor array with logarithmic delta-sigma architecture.

    PubMed

    Mahmoodi, Alireza; Li, Jing; Joseph, Dileepan

    2013-01-01

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

  8. Current progress on pixel level packaging for uncooled IRFPA

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  9. Hybrid microelectronic technology

    NASA Astrophysics Data System (ADS)

    Moran, P.

    Various areas of hybrid microelectronic technology are discussed. The topics addressed include: basic thick film processing, thick film pastes and substrates, add-on components and attachment methods, thin film processing, and design of thick film hybrid circuits. Also considered are: packaging hybrid circuits, automating the production of hybrid circuits, application of hybrid techniques, customer's view of hybrid technology, and quality control and assurance in hybrid circuit production.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  11. Readout chip for the CMS pixel detector upgrade

    NASA Astrophysics Data System (ADS)

    Rossini, Marco

    2014-11-01

    For the CMS experiment a new pixel detector is planned for installation during the extended shutdown in winter 2016/2017. Among the changes of the detector modified front end electronics will be used for higher efficiency at peak luminosity of the LHC and faster readout. The first prototype versions of the new readout chip have been designed and produced. The results of qualification and calibration for the new chip are presented in this paper.

  12. Influence of pixel geometry on the 1/f noise coefficient

    NASA Astrophysics Data System (ADS)

    Généreux, Francis; Paultre, Jacques-Edmond; Tremblay, Bruno; Provençal, Francis; Alain, Christine

    2013-06-01

    This paper presents a systematic study of the 1/f noise coefficient as a function of pixel geometry for microbolometer structures. Structures with various VOx widths, electrode gaps, electrode widths and via hole sizes were fabricated and characterized. The experimental results show that the 1/f noise coefficient is adversely affected by current non uniformity, in agreement with model predictions. Design parameters that significantly impact current non uniformity are identified and approaches to minimize their importance are proposed.

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

    NASA Astrophysics Data System (ADS)

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

    2006-09-01

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

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

    SciTech Connect

    Selcuk Cihangir and Simon Kwan

    2000-09-28

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

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

    PubMed Central

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

    2012-01-01

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

  16. Sub-pixel spatial resolution wavefront phase imaging

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

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

    SciTech Connect

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

    2009-07-15

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

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

    PubMed Central

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

    2009-01-01

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

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

    SciTech Connect

    Kemme, Shanalyn A.; Cruz-Cabrera, Alvaro Augusto; Boye, Robert R.; Samora, Sally; Carter, Tony Ray; Briggs, Ronald D.

    2010-03-01

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

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

    PubMed

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

    1995-10-10

    The high level of spatial uniformity in modern CCD's makes them excellent devices for astrometric instruments. However, at the level of accuracy envisioned by the more ambitious projects such as the Astrometric Imaging Telescope, current technology produces CCD's with significant pixel registration errors. We describe a technique for making high-precision measurements of relative pixel positions. We measured CCD's manufactured for the Wide Field Planetary Camera II installed in the Hubble Space Telescope. These CCD's are shown to have significant step-and-repeat errors of 0.033 pixel along every 34th row, as well as a 0.003-pixel curvature along 34-pixel stripes. The source of these errors is described. Our experiments achieved a per-pixel accuracy of 0.011 pixel. The ultimate shot-noise limited precision of the method is less than 0.001 pixel. PMID:21060522

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

    SciTech Connect

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

    2008-10-01

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

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

    PubMed Central

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

    2016-01-01

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

  3. Evaluation of color encodings for high dynamic range pixels

    NASA Astrophysics Data System (ADS)

    Boitard, Ronan; Mantiuk, Rafal K.; Pouli, Tania

    2015-03-01

    Traditional Low Dynamic Range (LDR) color spaces encode a small fraction of the visible color gamut, which does not encompass the range of colors produced on upcoming High Dynamic Range (HDR) displays. Future imaging systems will require encoding much wider color gamut and luminance range. Such wide color gamut can be represented using floating point HDR pixel values but those are inefficient to encode. They also lack perceptual uniformity of the luminance and color distribution, which is provided (in approximation) by most LDR color spaces. Therefore, there is a need to devise an efficient, perceptually uniform and integer valued representation for high dynamic range pixel values. In this paper we evaluate several methods for encoding colour HDR pixel values, in particular for use in image and video compression. Unlike other studies we test both luminance and color difference encoding in a rigorous 4AFC threshold experiments to determine the minimum bit-depth required. Results show that the Perceptual Quantizer (PQ) encoding provides the best perceptual uniformity in the considered luminance range, however the gain in bit-depth is rather modest. More significant difference can be observed between color difference encoding schemes, from which YDuDv encoding seems to be the most efficient.

  4. Hyperspectral pixel classification from coded-aperture compressive imaging

    NASA Astrophysics Data System (ADS)

    Ramirez, Ana; Arce, Gonzalo R.; Sadler, Brian M.

    2012-06-01

    This paper describes a new approach and its associated theoretical performance guarantees for supervised hyperspectral image classification from compressive measurements obtained by a Coded Aperture Snapshot Spectral Imaging System (CASSI). In one snapshot, the two-dimensional focal plane array (FPA) in the CASSI system captures the coded and spectrally dispersed source field of a three-dimensional data cube. Multiple snapshots are used to construct a set of compressive spectral measurements. The proposed approach is based on the concept that each pixel in the hyper-spectral image lies in a low-dimensional subspace obtained from the training samples, and thus it can be represented as a sparse linear combination of vectors in the given subspace. The sparse vector representing the test pixel is then recovered from the set of compressive spectral measurements and it is used to determine the class label of the test pixel. The theoretical performance bounds of the classifier exploit the distance preservation condition satisfied by the multiple shot CASSI system and depend on the number of measurements collected, code aperture pattern, and similarity between spectral signatures in the dictionary. Simulation experiments illustrate the performance of the proposed classification approach.

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

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

    PubMed

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

    2016-01-01

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

  7. Pixel diamond detectors for excimer laser beam diagnostics

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  8. A CMOS active pixel sensor for retinal stimulation

    NASA Astrophysics Data System (ADS)

    Prydderch, Mark L.; French, Marcus J.; Mathieson, Keith; Adams, Christopher; Gunning, Deborah; Laudanski, Jonathan; Morrison, James D.; Moodie, Alan R.; Sinclair, James

    2006-02-01

    Degenerative photoreceptor diseases, such as age-related macular degeneration and retinitis pigmentosa, are the most common causes of blindness in the western world. A potential cure is to use a microelectronic retinal prosthesis to provide electrical stimulation to the remaining healthy retinal cells. We describe a prototype CMOS Active Pixel Sensor capable of detecting a visual scene and translating it into a train of electrical pulses for stimulation of the retina. The sensor consists of a 10 x 10 array of 100 micron square pixels fabricated on a 0.35 micron CMOS process. Light incident upon each pixel is converted into output current pulse trains with a frequency related to the light intensity. These outputs are connected to a biocompatible microelectrode array for contact to the retinal cells. The flexible design allows experimentation with signal amplitudes and frequencies in order to determine the most appropriate stimulus for the retina. Neural processing in the retina can be studied by using the sensor in conjunction with a Field Programmable Gate Array (FPGA) programmed to behave as a neural network. The sensor has been integrated into a test system designed for studying retinal response. We present the most recent results obtained from this sensor.

  9. Digital pixel readout integrated circuit architectures for LWIR

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  10. Simulation of charge transport in pixelated CdTe

    NASA Astrophysics Data System (ADS)

    Kolstein, M.; Ariño, G.; Chmeissani, M.; De Lorenzo, G.

    2014-12-01

    The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated semiconductor technology for nuclear medicine applications to achieve an improved image reconstruction without efficiency loss. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 106). The design is based on the use of a pixelated CdTe Schottky detector to have optimal energy and spatial resolution. An individual read-out channel is dedicated for each detector voxel of size 1 × 1 × 2 mm3 using an application-specific integrated circuit (ASIC) which the VIP project has designed, developed and is currently evaluating experimentally. The behaviour of the signal charge carriers in CdTe should be well understood because it has an impact on the performance of the readout channels. For this purpose the Finite Element Method (FEM) Multiphysics COMSOL software package has been used to simulate the behaviour of signal charge carriers in CdTe and extract values for the expected charge sharing depending on the impact point and bias voltage. The results on charge sharing obtained with COMSOL are combined with GAMOS, a Geant based particle tracking Monte Carlo software package, to get a full evaluation of the amount of charge sharing in pixelated CdTe for different gamma impact points.

  11. Hexagonal Pixels and Indexing Scheme for Binary Images

    NASA Technical Reports Server (NTRS)

    Johnson, Gordon G.

    2004-01-01

    A scheme for resampling binaryimage data from a rectangular grid to a regular hexagonal grid and an associated tree-structured pixel-indexing scheme keyed to the level of resolution have been devised. This scheme could be utilized in conjunction with appropriate image-data-processing algorithms to enable automated retrieval and/or recognition of images. For some purposes, this scheme is superior to a prior scheme that relies on rectangular pixels: one example of such a purpose is recognition of fingerprints, which can be approximated more closely by use of line segments along hexagonal axes than by line segments along rectangular axes. This scheme could also be combined with algorithms for query-image-based retrieval of images via the Internet. A binary image on a rectangular grid is generated by raster scanning or by sampling on a stationary grid of rectangular pixels. In either case, each pixel (each cell in the rectangular grid) is denoted as either bright or dark, depending on whether the light level in the pixel is above or below a prescribed threshold. The binary data on such an image are stored in a matrix form that lends itself readily to searches of line segments aligned with either or both of the perpendicular coordinate axes. The first step in resampling onto a regular hexagonal grid is to make the resolution of the hexagonal grid fine enough to capture all the binaryimage detail from the rectangular grid. In practice, this amounts to choosing a hexagonal-cell width equal to or less than a third of the rectangular- cell width. Once the data have been resampled onto the hexagonal grid, the image can readily be checked for line segments aligned with the hexagonal coordinate axes, which typically lie at angles of 30deg, 90deg, and 150deg with respect to say, the horizontal rectangular coordinate axis. Optionally, one can then rotate the rectangular image by 90deg, then again sample onto the hexagonal grid and check for line segments at angles of 0deg, 60deg

  12. Method of fabrication of display pixels driven by silicon thin film transistors

    DOEpatents

    Carey, Paul G.; Smith, Patrick M.

    1999-01-01

    Display pixels driven by silicon thin film transistors are fabricated on plastic substrates for use in active matrix displays, such as flat panel displays. The process for forming the pixels involves a prior method for forming individual silicon thin film transistors on low-temperature plastic substrates. Low-temperature substrates are generally considered as being incapable of withstanding sustained processing temperatures greater than about 200.degree. C. The pixel formation process results in a complete pixel and active matrix pixel array. A pixel (or picture element) in an active matrix display consists of a silicon thin film transistor (TFT) and a large electrode, which may control a liquid crystal light valve, an emissive material (such as a light emitting diode or LED), or some other light emitting or attenuating material. The pixels can be connected in arrays wherein rows of pixels contain common gate electrodes and columns of pixels contain common drain electrodes. The source electrode of each pixel TFT is connected to its pixel electrode, and is electrically isolated from every other circuit element in the pixel array.

  13. The Speedster-EXD - A New Event-Triggered Hybrid CMOS X-ray Detector

    NASA Astrophysics Data System (ADS)

    Griffith, Christopher; Falcone, Abe; Prieskorn, Zach; Burrows, David

    2015-04-01

    We present the characterization of a new event driven x-ray hybrid CMOS detector developed by Penn State University in collaboration with Teledyne Imaging Sensors. Hybrid CMOS detectors currently have many advantages over CCDs including lower susceptibility to radiation damage, lower power consumption, and faster read-out time to avoid pile-up. The Speedster-EXD hybrid CMOS detector has many new features that improve upon the previous generation of detectors including two new in-pixel features that reduce noise from known noise sources: (1) a low-noise, high-gain CTIA amplifier to eliminate interpixel capacitance crosstalk and (2) in-pixel CDS subtraction to reduce kTC noise. The most exciting new feature of the Speedster-EXD is an in-pixel comparator that enables read out of only the pixels which contain signal from an x-ray event. The comparator threshold can be set by the user so that only pixels with signal above the set threshold are read out. This comparator feature can increase effective frame rate by orders of magnitude. We present the read noise, dark current, interpixel capacitance, energy resolution, and gain variation measurements of two Speedster-EXD detectors.

  14. Progress report on the use of hybrid silicon pin diode arrays in high energy physics

    SciTech Connect

    Shapiro, S.L. ); Jernigan, J.G.; Arens, J.F. . Space Sciences Lab.)

    1990-05-01

    We report on the successful effort to develop hybrid PIN diode arrays and to demonstrate their potential as components of vertex detectors. Hybrid pixel arrays have been fabricated by the Hughes Aircraft Co. by bump-bonding readout chips developed by Hughes to an array of PIN diodes manufactured by Micron Semiconductor Inc. These hybrid pixel arrays were constructed in two configurations. One array format has 10 {times} 64 pixels, each 120 {mu}m square; and the other format has 256 {times} 156 pixels, each 30 {mu}m square. In both cases, the thickness of the PIN diode layer is 300 {mu}m. Measurements of detector performance show that excellent position resolution can be achieved by interpolation. By determining the centroid of the charge cloud which spreads charge into a number of neighboring pixels, a spatial resolution of a few microns has been attained. The noise has been measured to be about 300 electrons (rms) at room temperature, as expected from KTC and dark current considerations, yielding a signal-to-noise ratio of about 100 for minimum ionizing particles. 4 refs., 17 figs.

  15. Hybrid Gear

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  16. Light emitting transistors: A new route for display pixels (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Namdas, Ebinazar B.

    2015-10-01

    Organic light emitting transistors (LEFETs) are an emerging class of light emitting devices that have been successfully demonstrated in single-layer [1] and mutli-layer device structures [2]. LEFETs can simultaneously execute light-emission and standard logic functions (ON/OFF) of a transistor in a single device architecture [1]. This dual functionality of LEFETs has a potential to offer a new route to simplify fabrication of display pixels. However, the key problem of existing LEFETs thus far has been their low external quantum efficiency (EQE) at high brightness, poor ON/OFF ratio, and mobility. More recently, hybrid light emitting transistors [3-4], consisting of solution processed n-type metal oxide (inorganic) as the charge transport layer and light emitting conjugated polymer (organic), have been used to achieve higher mobility, ON/OFF ratio and brightness. In this talk, I will discuss the various factors that currently influence device performance in LEFETs, and will provide insights into our recent progress in developing high-performance hybrid LEFETs. References: (1). E. B. Namdas, J. S. Swensen, P. Ledochowitsch, J. D. Yuen, D. Moses, A. J. Heeger, Adv. Mater.,20, 1321 (2008). (2). M. Ullah, K. Tandy, S. D. Yambem, M. Aljada, P. L. Burn, P. Meredith, E. B. Namdas. Adv. Mater. 25, 6213-6218 (2013). (3). B. Walker, M. Ullah, G. J. Chae, P. L Burn, S. Cho, J. Y. Kim, E. B. Namdas, J. H. Seo. Appl Phys Lett, 105, 183302 (2014). (4). K. Muhieddine, M. Ullah, B. N. Pal, P. Burn, E. B. Namdas, Adv. Mater. 26, 6410 (2014).

  17. Deep-UV interference lithography combined with masked contact lithography for pixel wiregrid patterns

    NASA Astrophysics Data System (ADS)

    Lombardo, David; Shah, Piyush; Guo, Pengfei; Sarangan, Andrew

    2016-04-01

    Pixelated wiregrids are of great interest in polarimetric imagers, but there are no straightforward methods available for combining the uniform exposures of laser interference with a masking system to achieve pixels at different rotational angles. In this work we demonstrate a 266nm deep-UV interference lithography combined with a traditional i-line contact lithography to create such pixels. Aluminum wiregrids are first made, following by etching to create the pixels, and then a planarizing molybdenum film is used before patterning subsequent pixel arrays. The etch contrast between the molybdenum and the aluminum enables the release of the planarizing layer.

  18. Preliminary Results from Small-Pixel CdZnTe and CdTe Arrays

    NASA Technical Reports Server (NTRS)

    Ramsey, B. D.; Sharma, D. P.; Meisner, J.; Austin, R. A.

    1999-01-01

    We have evaluated 2 small-pixel (0.75 mm) Cadmium-Zinc-Telluride arrays, and one Cadmium-Telluride array, all fabricated for MSFC by Metorex (Finland) and Baltic Science Institute (Riga, Latvia). Each array was optimized for operating temperature and collection bias. It was then exposed to Cadmium-109 and Iron-55 laboratory isotopes, to measure the energy resolution for each pixel and was then scanned with a finely-collimated x-ray beam, of width 50 micron, to examine pixel to pixel and inter-pixel charge collections efficiency. Preliminary results from these array tests will be presented.

  19. ) Hybrid Composite

    NASA Astrophysics Data System (ADS)

    Show, Bijay Kumar; Mondal, Dipak Kumar; Maity, Joydeep

    2014-12-01

    In this research work, the dry sliding wear behavior of 6351 Al-(4 vol.% SiC + 4 vol.% Al2O3) hybrid composite was investigated at low sliding speed (1 m/s) against a hardened EN 31 disk at different loads. In general, the wear mechanism involved adhesion (along with associated subsurface cracking and delamination) and microcutting abrasion at lower load. While at higher load, abrasive wear involving microcutting and microploughing along with adherent oxide formation was observed. The overall wear rate increased with increasing normal load. The massive particle clusters as well as individual reinforcement particles were found to stand tall to resist abrasive wear. Besides, at higher load, the generation of adherent nodular tribo-oxide through nucleation and epitaxial growth on existing Al2O3 particles lowered down the wear rate. Accordingly, at any normal load, 6351 Al-(4 vol.% SiC + 4 vol.% Al2O3) hybrid composite exhibited superior wear resistance (lower overall wear rate) than the reported wear resistance of monolithic 6351 Al alloy.

  20. Hybrid Simulator

    Energy Science and Technology Software Center (ESTSC)

    2005-10-15

    HybSim (short for Hybrid Simulator) is a flexible, easy to use screening tool that allows the user to quanti the technical and economic benefits of installing a village hybrid generating system and simulates systems with any combination of —Diesel generator sets —Photovoltaic arrays -Wind Turbines and -Battery energy storage systems Most village systems (or small population sites such as villages, remote military bases, small communities, independent or isolated buildings or centers) depend on diesel generationmore » systems for their source of energy. HybSim allows the user to determine other "sources" of energy that can greatly reduce the dollar to kilo-watt hour ratio. Supported by the DOE, Energy Storage Program, HybSim was initially developed to help analyze the benefits of energy storage systems in Alaskan villages. Soon after its development, other sources of energy were added providing the user with a greater range of analysis opportunities and providing the village with potentially added savings. In addition to village systems, HybSim has generated interest for use from military institutions in energy provisions and USAID for international village analysis.« less

  1. Radiation-hard active CMOS pixel sensors for HL-LHC detector upgrades

    NASA Astrophysics Data System (ADS)

    Backhaus, Malte

    2015-02-01

    The luminosity of the Large Hadron Collider (LHC) will be increased during the Long Shutdown of 2022 and 2023 (LS3) in order to increase the sensitivity of its experiments. A completely new inner detector for the ATLAS experiment needs to be developed to withstand the extremely harsh environment of the upgraded, so-called High-Luminosity LHC (HL-LHC). High radiation hardness as well as granularity is mandatory to cope with the requirements in terms of radiation damage as well as particle occupancy. A new silicon detector concept that uses commercial high voltage and/or high resistivity full complementary metal-oxide-semiconductor (CMOS) processes as active sensor for pixel and/or strip layers has risen high attention, because it potentially provides high radiation hardness and granularity and at the same time reduced price due to the commercial processing and possibly relaxed requirements for the hybridization technique. Results on the first prototypes characterized in a variety of laboratory as well as test beam environments are presented.

  2. Single-pixel camera with one graphene photodetector.

    PubMed

    Li, Gongxin; Wang, Wenxue; Wang, Yuechao; Yang, Wenguang; Liu, Lianqing

    2016-01-11

    Consumer cameras in the megapixel range are ubiquitous, but the improvement of them is hindered by the poor performance and high cost of traditional photodetectors. Graphene, a two-dimensional micro-/nano-material, recently has exhibited exceptional properties as a sensing element in a photodetector over traditional materials. However, it is difficult to fabricate a large-scale array of graphene photodetectors to replace the traditional photodetector array. To take full advantage of the unique characteristics of the graphene photodetector, in this study we integrated a graphene photodetector in a single-pixel camera based on compressive sensing. To begin with, we introduced a method called laser scribing for fabrication the graphene. It produces the graphene components in arbitrary patterns more quickly without photoresist contamination as do traditional methods. Next, we proposed a system for calibrating the optoelectrical properties of micro/nano photodetectors based on a digital micromirror device (DMD), which changes the light intensity by controlling the number of individual micromirrors positioned at + 12°. The calibration sensitivity is driven by the sum of all micromirrors of the DMD and can be as high as 10(-5)A/W. Finally, the single-pixel camera integrated with one graphene photodetector was used to recover a static image to demonstrate the feasibility of the single-pixel imaging system with the graphene photodetector. A high-resolution image can be recovered with the camera at a sampling rate much less than Nyquist rate. The study was the first demonstration for ever record of a macroscopic camera with a graphene photodetector. The camera has the potential for high-speed and high-resolution imaging at much less cost than traditional megapixel cameras. PMID:26832270

  3. Optical differentiation wavefront sensor based on binary pixelated transmission filters

    NASA Astrophysics Data System (ADS)

    Qiao, J.; Travinsky, A.; Ding, G.; Dorrer, C.

    2015-03-01

    High-resolution wavefront sensors are used in a wide range of applications. The Shack-Hartmann sensor is the industry standard and mostly used for this kind of analysis. However, with this sensor the analysis can only be performed for narrowband radiation, the recoverable curvature of the wavefront slopes is also restricted by the size of a single lens in the microlens array. The high-resolution Shack Hartmann wavefront sensor (>128×128) is also significantly expensive. The optical differentiation wavefront sensor, on the other hand, consists of only simple and therefore inexpensive components, offers greater signal to noise ratio, allows for high-resolution analysis of wavefront curvature, and is potentially capable of performing broadband measurements. When a transmission mask with linear attenuation along a spatial direction modulates the far field of an optical wave, the spatial wavefront slope along that direction can be recovered from the fluence in the near field after modulation. With two orthogonal measurements one can recover the complete wavefront of the optical wave. In this study the characteristics of such a wavefront sensor are investigated when the linear transmission modulation is implemented with a pixelated binary filter. Such a filter can be produced as a gray-scale quasi-continuous transmission pattern constructed using arrays of small (e.g., 10-micron) transparent or opaque pixels and therefore it can simply be fabricated by conventional lithography techniques. Simulations demonstrate the potential ability of such a pixelated filter to match the performance of a filter with continuously varying transmission, while offering the advantage of better transmission control and reduction of fabrication costs.

  4. High quality GPU rendering with displaced pixel shading

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Choi, Jae

    2006-03-01

    Direct volume rendering via consumer PC hardware has become an efficient tool for volume visualization. In particular, the volumetric ray casting, the most frequently used volume rendering technique, can be implemented by the shading language integrated with graphical processing units (GPU). However, to produce high-quality images offered by GPU-based volume rendering, a higher sampling rate is usually required. In this paper, we present an algorithm to generate high quality images with a small number of slices by utilizing displaced pixel shading technique. Instead of sampling points along a ray with the regular interval, the actual surface location is calculated by the linear interpolation between the outer and inner points, and this location is used as the displaced pixel for the iso-surface illumination. Multi-pass and early Z-culling techniques are applied to improve the rendering speed. The first pass simply locates and stores the exact surface depth of each ray using a few pixel instructions; then, the second pass uses instructions to shade the surface at the previous position. A new 3D edge detector from our previous research is integrated to provide more realistic rendering results compared with the widely used gradient normal estimator. To implement our algorithm, we have made a program named DirectView based on DirectX 9.0c and Microsoft High Level Shading Language (HLSL) for volume rendering. We tested two data sets and discovered that our algorithm can generate smoother and more accurate shading images with a small number of intermediate slices.

  5. Charge amplitude distribution of the Gossip gaseous pixel detector

    NASA Astrophysics Data System (ADS)

    Blanco Carballo, V. M.; Chefdeville, M.; Colas, P.; Giomataris, Y.; van der Graaf, H.; Gromov, V.; Hartjes, F.; Kluit, R.; Koffeman, E.; Salm, C.; Schmitz, J.; Smits, S. M.; Timmermans, J.; Visschers, J. L.

    2007-12-01

    The Gossip gaseous pixel detector is being developed for the detection of charged particles in extreme high radiation environments as foreseen close to the interaction point of the proposed super LHC. The detecting medium is a thin layer of gas. Because of the low density of this medium, only a few primary electron/ion pairs are created by the traversing particle. To get a detectable signal, the electrons drift towards a perforated metal foil (Micromegas) whereafter they are multiplied in a gas avalanche to provide a detectable signal. The gas avalanche occurs in the high field between the Micromegas and the pixel readout chip (ROC). Compared to a silicon pixel detector, Gossip features a low material budget and a low cooling power. An experiment using X-rays has indicated a possible high radiation tolerance exceeding 10 16 hadrons/cm 2. The amplified charge signal has a broad amplitude distribution due to the limited statistics of the primary ionization and the statistical variation of the gas amplification. Therefore, some degree of inefficiency is inevitable. This study presents experimental results on the charge amplitude distribution for CO 2/DME (dimethyl-ether) and Ar/iC 4H 10 mixtures. The measured curves were fitted with the outcome of a theoretical model. In the model, the physical Landau distribution is approximated by a Poisson distribution that is convoluted with the variation of the gas gain and the electronic noise. The value for the fraction of pedestal events is used for a direct calculation of the cluster density. For some gases, the measured cluster density is considerably lower than given in literature.

  6. A new pixels flipping method for huge watermarking capacity of the invoice font image.

    PubMed

    Li, Li; Hou, Qingzheng; Lu, Jianfeng; Xu, Qishuai; Dai, Junping; Mao, Xiaoyang; Chang, Chin-Chen

    2014-01-01

    Invoice printing just has two-color printing, so invoice font image can be seen as binary image. To embed watermarks into invoice image, the pixels need to be flipped. The more huge the watermark is, the more the pixels need to be flipped. We proposed a new pixels flipping method in invoice image for huge watermarking capacity. The pixels flipping method includes one novel interpolation method for binary image, one flippable pixels evaluation mechanism, and one denoising method based on gravity center and chaos degree. The proposed interpolation method ensures that the invoice image keeps features well after scaling. The flippable pixels evaluation mechanism ensures that the pixels keep better connectivity and smoothness and the pattern has highest structural similarity after flipping. The proposed denoising method makes invoice font image smoother and fiter for human vision. Experiments show that the proposed flipping method not only keeps the invoice font structure well but also improves watermarking capacity. PMID:25489606

  7. Large area CMOS bio-pixel array for compact high sensitive multiplex biosensing.

    PubMed

    Sandeau, Laure; Vuillaume, Cassandre; Contié, Sylvain; Grinenval, Eva; Belloni, Federico; Rigneault, Hervé; Owens, Roisin M; Fournet, Margaret Brennan

    2015-02-01

    A novel CMOS bio-pixel array which integrates assay substrate and assay readout is demonstrated for multiplex and multireplicate detection of a triplicate of cytokines with single digit pg ml(-1) sensitivities. Uniquely designed large area bio-pixels enable individual assays to be dedicated to and addressed by single pixels. A capability to simultaneously measure a large number of targets is provided by the 128 available pixels. Chemiluminescent assays are carried out directly on the pixel surface which also detects the emitted chemiluminescent photons, facilitating a highly compact sensor and reader format. The high sensitivity of the bio-pixel array is enabled by the high refractive index of silicon based pixels. This in turn generates a strong supercritical angle luminescence response significantly increasing the efficiency of the photon collection over conventional farfield modalities. PMID:25490928

  8. Design optimization of pixel sensors using device simulations for the phase-II CMS tracker upgrade

    NASA Astrophysics Data System (ADS)

    Jain, G.; Bhardwaj, A.; Dalal, R.; Eber, R.; Eichorn, T.; Fernandez, M.; Lalwani, K.; Messineo, A.; Palomo, F. R.; Peltola, T.; Printz, M.; Ranjan, K.; Villa, I.; Hidalgo, S.

    2016-07-01

    In order to address the problems caused by the harsh radiation environment during the high luminosity phase of the LHC (HL-LHC), all silicon tracking detectors (pixels and strips) in the CMS experiment will undergo an upgrade. And so to develop radiation hard pixel sensors, simulations have been performed using the 2D TCAD device simulator, SILVACO, to obtain design parameters. The effect of various design parameters like pixel size, pixel depth, implant width, metal overhang, p-stop concentration, p-stop depth and bulk doping density on the leakage current and critical electric field are studied for both non-irradiated as well as irradiated pixel sensors. These 2D simulation results of planar pixels are useful for providing insight into the behaviour of non-irradiated and irradiated silicon pixel sensors and further work on 3D simulation is underway.

  9. A New Pixels Flipping Method for Huge Watermarking Capacity of the Invoice Font Image

    PubMed Central

    Li, Li; Hou, Qingzheng; Lu, Jianfeng; Dai, Junping; Mao, Xiaoyang; Chang, Chin-Chen

    2014-01-01

    Invoice printing just has two-color printing, so invoice font image can be seen as binary image. To embed watermarks into invoice image, the pixels need to be flipped. The more huge the watermark is, the more the pixels need to be flipped. We proposed a new pixels flipping method in invoice image for huge watermarking capacity. The pixels flipping method includes one novel interpolation method for binary image, one flippable pixels evaluation mechanism, and one denoising method based on gravity center and chaos degree. The proposed interpolation method ensures that the invoice image keeps features well after scaling. The flippable pixels evaluation mechanism ensures that the pixels keep better connectivity and smoothness and the pattern has highest structural similarity after flipping. The proposed denoising method makes invoice font image smoother and fiter for human vision. Experiments show that the proposed flipping method not only keeps the invoice font structure well but also improves watermarking capacity. PMID:25489606

  10. Monolithic pixel detectors in a deep submicron SOI process

    SciTech Connect

    Deptuch, Grzegorz; /Fermilab

    2009-10-01

    A compact charge-signal processing chain, composed of a two-stage semi-gaussian preamplifier-signal shaping filter, a discriminator and a binary counter, implemented in a prototype pixel detector using 0.20 {micro}m CMOS Silicon on Insulator process, is presented. The gain of the analog chain was measured 0.76 V/fC at the signal peaking time about 300 ns and the equivalent noise charge referred to the input of 80 e{sup -1}.

  11. Wire bond vibration of forward pixel tracking detector of CMS

    SciTech Connect

    Atac, M.; Gobbi, B.; Kwan, S.; Pischalnikov, Y.; Spencer, E.; Sellberg, G.; Pavlicek, V.; /Fermilab

    2006-10-01

    Wire bonds of the Forward Pixel (FPix) tracking detectors are oriented in the direction that maximizes Lorentz Forces relative to the 4 Tesla field of the Compact Muon Solenoid (CMS) Detector's magnet. The CMS Experiment is under construction at the Large Hadron Collider at CERN, Geneva, Switzerland. We were concerned about Lorentz Force oscillating the wires at their fundamental frequencies and possibly fracturing or breaking them at their heels, as happened with the CDF wire bonds. This paper reports a study to understand what conditions break such bonds.

  12. Independent pixel and Monte Carlo estimates of stratocumulus albedo

    NASA Technical Reports Server (NTRS)

    Cahalan, Robert F.; Ridgway, William; Wiscombe, Warren J.; Gollmer, Steven; HARSHVARDHAN

    1994-01-01

    Monte Carlo radiative transfer methods are employed here to estimate the plane-parallel albedo bias for marine stratocumulus clouds. This is the bias in estimates of the mesoscale-average albedo, which arises from the assumption that cloud liquid water is uniformly distributed. The authors compare such estimates with those based on a more realistic distribution generated from a fractal model of marine stratocumulus clouds belonging to the class of 'bounded cascade' models. In this model the cloud top and base are fixed, so that all variations in cloud shape are ignored. The model generates random variations in liquid water along a single horizontal direction, forming fractal cloud streets while conserving the total liquid water in the cloud field. The model reproduces the mean, variance, and skewness of the vertically integrated cloud liquid water, as well as its observed wavenumber spectrum, which is approximately a power law. The Monte Carlo method keeps track of the three-dimensional paths solar photons take through the cloud field, using a vectorized implementation of a direct technique. The simplifications in the cloud field studied here allow the computations to be accelerated. The Monte Carlo results are compared to those of the independent pixel approximation, which neglects net horizontal photon transport. Differences between the Monte Carlo and independent pixel estimates of the mesoscale-average albedo are on the order of 1% for conservative scattering, while the plane-parallel bias itself is an order of magnitude larger. As cloud absorption increases, the independent pixel approximation agrees even more closely with the Monte Carlo estimates. This result holds for a wide range of sun angles and aspect ratios. Thus, horizontal photon transport can be safely neglected in estimates of the area-average flux for such cloud models. This result relies on the rapid falloff of the wavenumber spectrum of stratocumulus, which ensures that the smaller

  13. FITPix — fast interface for Timepix pixel detectors

    NASA Astrophysics Data System (ADS)

    Kraus, V.; Holik, M.; Jakubek, J.; Kroupa, M.; Soukup, P.; Vykydal, Z.

    2011-01-01

    The semiconductor pixel detector Timepix contains an array of 256 × 256 square pixels with pitch 55 μm. In addition to high spatial granularity the single quantum counting detector Timepix can provide also energy or time information in each pixel. This device is a powerful tool for radiation and particle detection, imaging and tracking. A new readout interface for silicon pixel detectors of the Medipix family has been developed in our group in order to provide a higher frame rate and enhanced flexibility of operation. The interface consists of a field programmable gate array, a USB 2.0 interface chip, DAC, ADC and a circuit which generates bias voltage for the sensor. The main control system is placed in the FPGA circuit which fully controls the Timepix device. This approach offers an easy way how to include new functionality and extended operation. The interface for Timepix supports all operation modes of the detector (counting, TOT, timing). The FITPix is a successor of the USB 1.22 Interface and the electronic readout is built with the latest available components, which allows achieving up to 90 frames per second with a single detector. The frame rate is about 20 times faster compared to the previous system while it maintains all same capabilities supported. In addition FITPix newly enables an adjustable clock frequency and hardware triggering which is a useful tool when there is the need for synchronized operation of multiple devices. Three modes of hardware trigger have been implemented: hardware trigger which starts the measurement, hardware trigger which terminates the measurement and hardware trigger which controls measurement fully. The entire system is fully powered through the USB bus. FITPix supports also readout from several detectors in chain in which case just an external power source is required. FITPix is a fully flexible device and the user needs no other equipment. FITPix combines high performance and mobility and it opens new fields of

  14. Current-mode CMOS hybrid image sensor

    NASA Astrophysics Data System (ADS)

    Benyhesan, Mohammad Kassim

    Digital imaging is growing rapidly making Complimentary Metal-Oxide-Semi conductor (CMOS) image sensor-based cameras indispensable in many modern life devices like cell phones, surveillance devices, personal computers, and tablets. For various purposes wireless portable image systems are widely deployed in many indoor and outdoor places such as hospitals, urban areas, streets, highways, forests, mountains, and towers. However, the increased demand on high-resolution image sensors and improved processing features is expected to increase the power consumption of the CMOS sensor-based camera systems. Increased power consumption translates into a reduced battery life-time. The increased power consumption might not be a problem if there is access to a nearby charging station. On the other hand, the problem arises if the image sensor is located in widely spread areas, unfavorable to human intervention, and difficult to reach. Given the limitation of energy sources available for wireless CMOS image sensor, an energy harvesting technique presents a viable solution to extend the sensor life-time. Energy can be harvested from the sun light or the artificial light surrounding the sensor itself. In this thesis, we propose a current-mode CMOS hybrid image sensor capable of energy harvesting and image capture. The proposed sensor is based on a hybrid pixel that can be programmed to perform the task of an image sensor and the task of a solar cell to harvest energy. The basic idea is to design a pixel that can be configured to exploit its internal photodiode to perform two functions: image sensing and energy harvesting. As a proof of concept a 40 x 40 array of hybrid pixels has been designed and fabricated in a standard 0.5 microm CMOS process. Measurement results show that up to 39 microW of power can be harvested from the array under 130 Klux condition with an energy efficiency of 220 nJ /pixel /frame. The proposed image sensor is a current-mode image sensor which has several

  15. Hybrid-Based Dense Stereo Matching

    NASA Astrophysics Data System (ADS)

    Chuang, T. Y.; Ting, H. W.; Jaw, J. J.

    2016-06-01

    Stereo matching generating accurate and dense disparity maps is an indispensable technique for 3D exploitation of imagery in the fields of Computer vision and Photogrammetry. Although numerous solutions and advances have been proposed in the literature, occlusions, disparity discontinuities, sparse texture, image distortion, and illumination changes still lead to problematic issues and await better treatment. In this paper, a hybrid-based method based on semi-global matching is presented to tackle the challenges on dense stereo matching. To ease the sensitiveness of SGM cost aggregation towards penalty parameters, a formal way to provide proper penalty estimates is proposed. To this end, the study manipulates a shape-adaptive cross-based matching with an edge constraint to generate an initial disparity map for penalty estimation. Image edges, indicating the potential locations of occlusions as well as disparity discontinuities, are approved by the edge drawing algorithm to ensure the local support regions not to cover significant disparity changes. Besides, an additional penalty parameter 𝑃𝑒 is imposed onto the energy function of SGM cost aggregation to specifically handle edge pixels. Furthermore, the final disparities of edge pixels are found by weighting both values derived from the SGM cost aggregation and the U-SURF matching, providing more reliable estimates at disparity discontinuity areas. Evaluations on Middlebury stereo benchmarks demonstrate satisfactory performance and reveal the potency of the hybrid-based dense stereo matching method.

  16. Image analysis in comparative genomic hybridization

    SciTech Connect

    Lundsteen, C.; Maahr, J.; Christensen, B.

    1995-01-01

    Comparative genomic hybridization (CGH) is a new technique by which genomic imbalances can be detected by combining in situ suppression hybridization of whole genomic DNA and image analysis. We have developed software for rapid, quantitative CGH image analysis by a modification and extension of the standard software used for routine karyotyping of G-banded metaphase spreads in the Magiscan chromosome analysis system. The DAPI-counterstained metaphase spread is karyotyped interactively. Corrections for image shifts between the DAPI, FITC, and TRITC images are done manually by moving the three images relative to each other. The fluorescence background is subtracted. A mean filter is applied to smooth the FITC and TRITC images before the fluorescence ratio between the individual FITC and TRITC-stained chromosomes is computed pixel by pixel inside the area of the chromosomes determined by the DAPI boundaries. Fluorescence intensity ratio profiles are generated, and peaks and valleys indicating possible gains and losses of test DNA are marked if they exceed ratios below 0.75 and above 1.25. By combining the analysis of several metaphase spreads, consistent findings of gains and losses in all or almost all spreads indicate chromosomal imbalance. Chromosomal imbalances are detected either by visual inspection of fluorescence ratio (FR) profiles or by a statistical approach that compares FR measurements of the individual case with measurements of normal chromosomes. The complete analysis of one metaphase can be carried out in approximately 10 minutes. 8 refs., 7 figs., 1 tab.

  17. PIXIE III: a very large area photon-counting CMOS pixel ASIC for sharp X-ray spectral imaging

    NASA Astrophysics Data System (ADS)

    Bellazzini, R.; Brez, A.; Spandre, G.; Minuti, M.; Pinchera, M.; Delogu, P.; de Ruvo, P. L.; Vincenzi, A.

    2015-01-01

    PIXIE III is the third generation of very large area (32 × 25 mm2) pixel ASICs developed by Pixirad Imaging Counters s.r.l. to be used in combination with suitable X-ray sensor materials (Silicon, CdTe, GaAs) in hybrid assemblies using flip-chip bonding. A Pixirad unit module based on PIXIE III shows several advances compared to what has been available up to now. It has a very broad energy range (from 2 to 100 keV before full pulse saturation), high speed (100 ns peaking time), high frame rate (larger than 500 fps), dead-time-free operation, good energy resolution (around 2 keV at 20 keV), high photo-peak fraction and sharp spectral separation between the color images. In this paper the results obtained with PIXIE III both in a test bench set-up as well in X-ray imaging applications are discussed.

  18. High speed data transmission on small gauge cables for the ATLAS Phase-II Pixel detector upgrade

    NASA Astrophysics Data System (ADS)

    Shahinian, J.; Volk, J.; Fadeyev, V.; Grillo, A. A.; Meimban, B.; Nielsen, J.; Wilder, M.

    2016-03-01

    The High Luminosity LHC will present a number of challenges for the upgraded ATLAS detector. In particular, data transmission requirements for the upgrade of the ATLAS Pixel detector will be difficult to meet. The expected trigger rate and occupancy imply multi-gigabit per second transmission rates will be required but radiation levels at the smallest radius preclude completely optical solutions. Electrical transmission up to distances of 7m will be necessary to move optical components to an area with lower radiation levels. Here, we explore the use of small gauge electrical cables as a high-bandwidth, radiation hard solution with a sufficiently small radiation length. In particular, we present a characterization of various twisted wire pair (TWP) configurations of various material structures, including measurements of their bandwidth, crosstalk, and radiation hardness. We find that a custom ``hybrid'' cable consisting of 1m of a multi-stranded TWP with Poly-Ether-Ether-Ketone (PEEK) insulation and a thin Al shield followed by 6m of a thin twin-axial cable presents a low-mass solution that fulfills bandwidth requirements and is expected to be sufficiently radiation hard. Additionally, we discuss preliminary results of using measured S-parameters to produce a SPICE model for a 1m sample of the custom TWP to be used for the development of new pixel readout chips.

  19. Development of Pattern Recognition Software for Tracks of Ionizing Radiation In Medipix2-Based (TimePix) Pixel Detector Devices

    NASA Astrophysics Data System (ADS)

    Vilalta, R.; Kuchibhotla, S.; Valerio, R.; Pinsky, L.

    2011-12-01

    The principal aim of our project is to develop an efficient pattern recognition tool for the automated identification and classification of tracks of ionizing radiation as measured by a TimePix version of the hybrid semiconductor Medipix2 pixel detector system. Such a software tool would have a number of applications including dosimeters to assess the risk of human exposure to radiation, and area monitors to characterize the general background radiation environment harmful to humans and electronic equipment. We are particularly interested in the development of the real-time analysis software needed to support an operational dosimeter that can assess the radiation environment during space missions. Our software development project makes use of data taken in beams of heavy ions at HIMAC (Heavy Ion Medical Accelerator Facility) in Chiba, Japan, including data from several different heavy ions with similar Linear Energy Transfers (LETs) for calibration purposes. We describe two modules of our pattern recognition tool: feature generation and classification. Our first module builds on a segmentation algorithm that identifies tracks from the pixel image assuming an approximately elliptical form that varies in size and degree of elongation based on multiple factors, including the particle species and angle of incidence. Determining the charge and energy of the particles creating each track is a particularly challenging task because different energy and charge incident particles can produce very similar patterns. Our classification module invokes different algorithms such as decision trees, support vector machines, and Bayesian classifiers.

  20. Photon counting X-ray imaging with CdTe pixel detectors based on XPAD2 circuit

    NASA Astrophysics Data System (ADS)

    Franchi, Romain; Glasser, Francis; Gasse, Adrien; Clemens, Jean-Claude

    2006-07-01

    A semiconductor hybrid pixel detector for photon counting X-ray imaging has been developed and tested under radiation. The sensor is based on recent uniform CdTe single crystal associated with XPAD 2 counting chip via innovative processes of interconnection. The building detector is 1 mm thick, with an area of 1 cm 2 and consists of 600 square pixels cells 330 μm side. The readout chip working in electron collection mode is capable of setting homogeneous threshold with only a dispersion of 730 e -. Maximum noise level has been evaluated around 15 keV. First experiments under X-rays demonstrate a very good efficiency of detection. Moreover, imaging system allows excellent linearity over a large-scale achieving count rate of 3×10 6 photons/s/mm 2. Spectrometric measurements point up the system potential in multi-energies applications by locating and resolving X-rays lines of 241Am and 57Co sources.

  1. Hybridized tetraquarks

    NASA Astrophysics Data System (ADS)

    Esposito, A.; Pilloni, A.; Polosa, A. D.

    2016-07-01

    We propose a new interpretation of the neutral and charged X , Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules but rather a manifestation of the interplay between the two. While meson molecules need a negative or zero binding energy, its counterpart for h-tetraquarks is required to be positive. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs0 π± channel by the D0 Collaboration and the negative result presented subsequently by the LHCb Collaboration are understood in this scheme, together with a considerable portion of available data on X , Z particles. Considerations on a state with the same quantum numbers as the X (5568) are also made.

  2. Characterization of a hybrid energy-resolving photon-counting detector

    NASA Astrophysics Data System (ADS)

    Zang, A.; Pelzer, G.; Anton, G.; Ballabriga Sune, R.; Bisello, F.; Campbell, M.; Fauler, A.; Fiederle, M.; Llopart Cudie, X.; Ritter, I.; Tennert, F.; Wölfel, S.; Wong, W. S.; Michel, T.

    2014-03-01

    Photon-counting detectors in medical x-ray imaging provide a higher dose efficiency than integrating detectors. Even further possibilities for imaging applications arise, if the energy of each photon counted is measured, as for example K-edge-imaging or optimizing image quality by applying energy weighting factors. In this contribution, we show results of the characterization of the Dosepix detector. This hybrid photon- counting pixel detector allows energy resolved measurements with a novel concept of energy binning included in the pixel electronics. Based on ideas of the Medipix detector family, it provides three different modes of operation: An integration mode, a photon-counting mode, and an energy-binning mode. In energy-binning mode, it is possible to set 16 energy thresholds in each pixel individually to derive a binned energy spectrum in every pixel in one acquisition. The hybrid setup allows using different sensor materials. For the measurements 300 μm Si and 1 mm CdTe were used. The detector matrix consists of 16 x 16 square pixels for CdTe (16 x 12 for Si) with a pixel pitch of 220 μm. The Dosepix was originally intended for applications in the field of radiation measurement. Therefore it is not optimized towards medical imaging. The detector concept itself still promises potential as an imaging detector. We present spectra measured in one single pixel as well as in the whole pixel matrix in energy-binning mode with a conventional x-ray tube. In addition, results concerning the count rate linearity for the different sensor materials are shown as well as measurements regarding energy resolution.

  3. The speedster-EXD: a new event-triggered hybrid CMOS x-ray detector

    NASA Astrophysics Data System (ADS)

    Griffith, Christopher V.; Falcone, Abraham D.; Prieskorn, Zachary R.; Burrows, David N.

    2014-07-01

    We present preliminary characterization of the Speedster-EXD, a new event driven hybrid CMOS detector (HCD) developed in collaboration with Penn State University and Teledyne Imaging Systems. HCDs have advantages over CCDs including lower susceptibility to radiation damage, lower power consumption, and faster read-out time to avoid pile-up. They are deeply depleted and able to detect x-rays down to approximately 0.1 keV. The Speedster-EXD has additional in-pixel features compared to previously published HCDs including: (1) an in-pixel comparator that enables read out of only the pixels with signal from an x-ray event, (2) four different gain modes to optimize either full well capacity or energy resolution, (3) in-pixel CDS subtraction to reduce read noise, and (4) a low-noise, high-gain CTIA amplifier to eliminate interpixel capacitance crosstalk. When using the comparator feature, the user can set a comparator threshold and only pixels above the threshold will be read out. This feature can be run in two modes including single pixel readout in which only pixels above the threshold are read out and 3x3 readout where a 3×3 region centered on the central pixel of the X-ray event is read out. The comparator feature of the Speedster-EXD increases the detector array effective frame rate by orders of magnitude. The new features of the Speedster-EXD hybrid CMOS x-ray detector are particularly relevant to future high throughput x-ray missions requiring large-format silicon imagers.

  4. Memory color assisted illuminant estimation through pixel clustering

    NASA Astrophysics Data System (ADS)

    Zhang, Heng; Quan, Shuxue

    2010-01-01

    The under constrained nature of illuminant estimation determines that in order to resolve the problem, certain assumptions are needed, such as the gray world theory. Including more constraints in this process may help explore the useful information in an image and improve the accuracy of the estimated illuminant, providing that the constraints hold. Based on the observation that most personal images have contents of one or more of the following categories: neutral objects, human beings, sky, and plants, we propose a method for illuminant estimation through the clustering of pixels of gray and three dominant memory colors: skin tone, sky blue, and foliage green. Analysis shows that samples of the above colors cluster around small areas under different illuminants and their characteristics can be used to effectively detect pixels falling into each of the categories. The algorithm requires the knowledge of the spectral sensitivity response of the camera, and a spectral database consisted of the CIE standard illuminants and reflectance or radiance database of samples of the above colors.

  5. Multilayer fluorescence imaging on a single-pixel detector

    PubMed Central

    Guo, Kaikai; Jiang, Shaowei; Zheng, Guoan

    2016-01-01

    A critical challenge for fluorescence imaging is the loss of high frequency components in the detection path. Such a loss can be related to the limited numerical aperture of the detection optics, aberrations of the lens, and tissue turbidity. In this paper, we report an imaging scheme that integrates multilayer sample modeling, ptychography-inspired recovery procedures, and lensless single-pixel detection to tackle this challenge. In the reported scheme, we directly placed a 3D sample on top of a single-pixel detector. We then used a known mask to generate speckle patterns in 3D and scanned this known mask to different positions for sample illumination. The sample was then modeled as multiple layers and the captured 1D fluorescence signals were used to recover multiple sample images along the z axis. The reported scheme may find applications in 3D fluorescence sectioning, time-resolved and spectrum-resolved imaging. It may also find applications in deep-tissue fluorescence imaging using the memory effect.

  6. The pixel detector for the CMS phase-II upgrade

    NASA Astrophysics Data System (ADS)

    Dinardo, M. E.

    2015-04-01

    The high luminosity phase of the Large Hadron Collider (HL-LHC) requires a major pixel detector R&D effort to develop both readout chip and sensor that are capable to withstand unprecedented extremely high radiation. The target integrated luminosity of 3000 fb-1, that the HL-LHC is expected to deliver over about 10 years of operation, translates into a hadron fluence of 2×1016 1 MeV eq.n. / cm2, or equivalently 10 MGy of radiation dose in silicon, at about 3 cm from the interaction region where the first layer of the pixel detector could be located. The CMS collaboration has undertaken two baseline sensor R&D programs on thin n-on-p planar and 3D silicon sensor technologies. Together with the ATLAS collaboration it has also been established a common R&D effort for the development of the readout chip in the 65 nm CMOS technology. Status, progresses, and prospects of the CMS R&D effort are presented and discussed in this article.

  7. Influence of TFT-LCD Pixels Structure on Holographic Encoding

    NASA Astrophysics Data System (ADS)

    Hongjun, Wang; Ailing, Tian; Bingcai, Liu; Chunhui, Wang

    The LCD is proposed as a new hologram loader with the advantage that the hologram image is controlled digitally with no any mechanical moving and rotating elements. Different hologram image can be readily introduced by changing the coded image displayed on the LCD. A basic problem in which LCD is a hologram image loader is limited LCD's pixel number. In CGH, the sample point number have great impact on holographic representation. So the choice of sample point number is very important. When the LCD is phase hologram image loader, the phase on hologram image was decided by phase distribution of recorded wavefront on LCD plane. In phase hologram encoding, the pixel spacing is sampling interval of recorded wavefront. Based on sampling theory, the frequency band can be obtained by spectrum analysis. For different wavefront shape, A model was developed for phase rate, the spectrum distribution was got, the phase rate which can be recorded by LCD can be got. A didactic example is included to illustrate the computational procedure.

  8. Multilayer fluorescence imaging on a single-pixel detector.

    PubMed

    Guo, Kaikai; Jiang, Shaowei; Zheng, Guoan

    2016-07-01

    A critical challenge for fluorescence imaging is the loss of high frequency components in the detection path. Such a loss can be related to the limited numerical aperture of the detection optics, aberrations of the lens, and tissue turbidity. In this paper, we report an imaging scheme that integrates multilayer sample modeling, ptychography-inspired recovery procedures, and lensless single-pixel detection to tackle this challenge. In the reported scheme, we directly placed a 3D sample on top of a single-pixel detector. We then used a known mask to generate speckle patterns in 3D and scanned this known mask to different positions for sample illumination. The sample was then modeled as multiple layers and the captured 1D fluorescence signals were used to recover multiple sample images along the z axis. The reported scheme may find applications in 3D fluorescence sectioning, time-resolved and spectrum-resolved imaging. It may also find applications in deep-tissue fluorescence imaging using the memory effect. PMID:27446679

  9. A CMOS Active Pixel Sensor for Charged Particle Detection

    SciTech Connect

    Matis, Howard S.; Bieser, Fred; Kleinfelder, Stuart; Rai, Gulshan; Retiere, Fabrice; Ritter, Hans George; Singh, Kunal; Wurzel, Samuel E.; Wieman, Howard; Yamamoto, Eugene

    2002-12-02

    Active Pixel Sensor (APS) technology has shown promise for next-generation vertex detectors. This paper discusses the design and testing of two generations of APS chips. Both are arrays of 128 by 128 pixels, each 20 by 20 {micro}m. Each array is divided into sub-arrays in which different sensor structures (4 in the first version and 16 in the second) and/or readout circuits are employed. Measurements of several of these structures under Fe{sup 55} exposure are reported. The sensors have also been irradiated by 55 MeV protons to test for radiation damage. The radiation increased the noise and reduced the signal. The noise can be explained by shot noise from the increased leakage current and the reduction in signal is due to charge being trapped in the epi layer. Nevertheless, the radiation effect is small for the expected exposures at RHIC and RHIC II. Finally, we describe our concept for mechanically supporting a thin silicon wafer in an actual detector.

  10. Amplifier based broadband pixel for sub-millimeter wave imaging

    NASA Astrophysics Data System (ADS)

    Sarkozy, Stephen; Drewes, Jonathan; Leong, Kevin M. K. H.; Lai, Richard; Mei, X. B. (Gerry); Yoshida, Wayne; Lange, Michael D.; Lee, Jane; Deal, William R.

    2012-09-01

    Broadband sub-millimeter wave technology has received significant attention for potential applications in security, medical, and military imaging. Despite theoretical advantages of reduced size, weight, and power compared to current millimeter wave systems, sub-millimeter wave systems have been hampered by a fundamental lack of amplification with sufficient gain and noise figure properties. We report a broadband pixel operating from 300 to 340 GHz, biased off a single 2 V power supply. Over this frequency range, the amplifiers provide > 40 dB gain and <8 dB noise figure, representing the current state-of-art performance capabilities. This pixel is enabled by revolutionary enhancements to indium phosphide (InP) high electron mobility transistor technology, based on a sub-50 nm gate and indium arsenide composite channel with a projected maximum oscillation frequency fmax>1.0 THz. The first sub-millimeter wave-based images using active amplification are demonstrated as part of the Joint Improvised Explosive Device Defeat Organization Longe Range Personnel Imager Program. This development and demonstration may bring to life future sub-millimeter-wave and THz applications such as solutions to brownout problems, ultra-high bandwidth satellite communication cross-links, and future planetary exploration missions.

  11. Large format, small pixel pitch and hot detectors at SOFRADIR

    NASA Astrophysics Data System (ADS)

    Reibel, Y.; Rouvie, A.; Nedelcu, A.; Augey, T.; Pere-Laperne, N.; Rubaldo, L.; Billon-Lanfrey, D.; Gravrand, O.; Rothman, J.; Destefanis, G.

    2013-10-01

    Recently Sofradir joined a very small circle of IR detector manufacturers with expertise every aspect of the cooled and uncooled IR technologies, all under one roof by consolidating all IR technologies available in France. These different technologies are complementary and are used depending of the needs of the applications mainly concerning the detection range needs as well as their ability to detect in bad weather environmental conditions. SNAKE (InGaAs) and SCORPIO LW (MCT) expand Sofradir's line of small pixel pitch TV format IR detectors from the mid-wavelength to the short and long wavelengths. Our dual band MW-LW QWIP detectors (25μm, 384×288 pixels) benefit to tactical platforms giving an all-weather performance and increasing flexibility in the presence of battlefield obscurants. In parallel we have been pursuing further infrared developments on future MWIR detectors, such as the VGA format HOT detector that consumes 2W and the 10μm pitch IR detector which gives us a leading position in innovation. These detectors are designed for long-range surveillance equipment, commander or gunner sights, ground-to-ground missile launchers and other applications that require higher resolution and sensitivity to improve reconnaissance and target identification. This paper discusses the system level performance in each detector type.

  12. A generic readout environment for prototype pixel detectors

    NASA Astrophysics Data System (ADS)

    Turqueti, Marcos; Rivera, Ryan; Prosser, Alan; Kwan, Simon

    2010-11-01

    Pixel detectors for experimental particle physics research have been implemented with a variety of readout formats and potentially generate massive amounts of data. Examples include the PSI46 device for the Compact Muon Solenoid (CMS) experiment which implements an analog readout, the Fermilab FPIX2.1 device with a digital readout, and the Fermilab Vertically Integrated Pixel device. The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory has developed a data acquisition system flexible and powerful enough to meet the various needs of these devices to support laboratory test bench as well as test beam applications. The system is called CAPTAN (Compact And Programmable daTa Acquisition Node) and is characterized by its flexibility, versatility and scalability by virtue of several key architectural features. These include a vertical bus that permits the user to stack multiple boards, a gigabit Ethernet link that permits high speed communications to the system and a core group of boards that provide specific processing and readout capabilities for the system. System software based on distributed computing techniques supports an expandable network of CAPTANs. In this paper, we describe the system architecture and give an overview of its capabilities.

  13. Monolithic Active Pixel Matrix with Binary Counters (MAMBO) ASIC

    SciTech Connect

    Khalid, Farah F.; Deptuch, Grzegorz; Shenai, Alpana; Yarema, Raymond J.; /Fermilab

    2010-11-01

    Monolithic Active Matrix with Binary Counters (MAMBO) is a counting ASIC designed for detecting and measuring low energy X-rays from 6-12 keV. Each pixel contains analogue functionality implemented with a charge preamplifier, CR-RC{sup 2} shaper and a baseline restorer. It also contains a window comparator which can be trimmed by 4 bit DACs to remove systematic offsets. The hits are registered by a 12 bit ripple counter which is reconfigured as a shift register to serially output the data from the entire ASIC. Each pixel can be tested individually. Two diverse approaches have been used to prevent coupling between the detector and electronics in MAMBO III and MAMBO IV. MAMBO III is a 3D ASIC, the bottom ASIC consists of diodes which are connected to the top ASIC using {mu}-bump bonds. The detector is decoupled from the electronics by physically separating them on two tiers and using several metal layers as a shield. MAMBO IV is a monolithic structure which uses a nested well approach to isolate the detector from the electronics. The ASICs are being fabricated using the SOI 0.2 {micro}m OKI process, MAMBO III is 3D bonded at T-Micro and MAMBO IV nested well structure was developed in collaboration between OKI and Fermilab.

  14. Monolithic active pixel matrix with binary counters (MAMBO III) ASIC

    SciTech Connect

    Khalid, Farah; Deptuch, Grzegorz; Shenai, Alpana; Yarema, Raymond; /Fermilab

    2010-01-01

    Monolithic Active Matrix with Binary Counters (MAMBO) is a counting ASIC designed for detecting and measuring low energy X-rays from 6-12keV. Each pixel contains analogue functionality implemented with a charge preamplifier, CR-RC{sup 2} shaper and a baseline restorer. It also contains a window comparator which can be trimmed by 4 bit DACs to remove systematic offsets. The hits are registered by a 12 bit ripple counter which is reconfigured as a shift register to serially output the data from the entire ASIC. Each pixel can be tested individually. Two diverse approaches have been used to prevent coupling between the detector and electronics in MAMBO III and MAMBO IV. MAMBO III is a 3D ASIC, the bottom ASIC consists of diodes which are connected to the top ASIC using {mu}-bump bonds. The detector is decoupled from the electronics by physically separating them on two tiers and using several metal layers as a shield. MAMBO IV is a monolithic structure which uses a nested well approach to isolate the detector from the electronics. The ASICs are being fabricated using the SOI 0.2 {micro}m OKI process, MAMBO III is 3D bonded at T-Micro and MAMBO IV nested well structure was developed in collaboration between OKI and Fermilab.

  15. Pixel structure for asymmetry removal in ToF 3D camera

    NASA Astrophysics Data System (ADS)

    Kang, Byongmin; Shin, Jungsoon; Choi, Jaehyuk; Kim, James D. K.

    2014-03-01

    Most of time-of-flight (ToF) cameras have a 2-tap pixel structure for demodulating a reflected near infrared (NIR) from objects. In order to eliminate the asymmetry between two taps in the pixel, a ToF camera needs another measurement, which collects photo-generated electrons from reflected NIR by inverting the phase of clock signals to transfer gates. This asymmetry removal needs additional frame memories and suppresses the frame rate due to the additional timing budget. In this paper, we propose novel asymmetry removal scheme without timing and area overheads by employing 2×2 shared 2-tap pixels with cross-connected transfer gates. The 2-tap pixel is shared with neighbor pixels and transfer gates in the pixel are cross-connected between upper and lower pixels. In order to verify the proposed pixel architecture, an electron charge generated in floating diffusion is simulated. And then we try to calculate a depth from camera to objects using simulated electron charge and measure a linearity of depth. In simulation result, proposed pixel architecture has more linear graph than conventional pixel structure along the real distance of objects.

  16. Integrated Lens Antennas for Multi-Pixel Receivers

    NASA Technical Reports Server (NTRS)

    Lee, Choonsup; Chattopadhyay, Goutam

    2011-01-01

    Future astrophysics and planetary experiments are expected to require large focal plane arrays with thousands of detectors. Feedhorns have excellent performance, but their mass, size, fabrication challenges, and expense become prohibitive for very large focal plane arrays. Most planar antenna designs produce broad beam patterns, and therefore require additional elements for efficient coupling to the telescope optics, such as substrate lenses or micromachined horns. An antenna array with integrated silicon microlenses that can be fabricated photolithographically effectively addresses these issues. This approach eliminates manual assembly of arrays of lenses and reduces assembly errors and tolerances. Moreover, an antenna array without metallic horns will reduce mass of any planetary instrument significantly. The design has a monolithic array of lens-coupled, leaky-wave antennas operating in the millimeter- and submillimeter-wave frequencies. Electromagnetic simulations show that the electromagnetic fields in such lens-coupled antennas are mostly confined in approximately 12 15 . This means that one needs to design a small-angle sector lens that is much easier to fabricate using standard lithographic techniques, instead of a full hyper-hemispherical lens. Moreover, this small-angle sector lens can be easily integrated with the antennas in an array for multi-pixel imager and receiver implementation. The leaky antenna is designed using double-slot irises and fed with TE10 waveguide mode. The lens implementation starts with a silicon substrate. Photoresist with appropriate thickness (optimized for the lens size) is spun on the substrate and then reflowed to get the desired lens structure. An antenna array integrated with individual lenses for higher directivity and excellent beam profile will go a long way in realizing multi-pixel arrays and imagers. This technology will enable a new generation of compact, low-mass, and highly efficient antenna arrays for use in multi-pixel

  17. Progress on the FDM Development at SRON: Toward 160 Pixels

    NASA Astrophysics Data System (ADS)

    den Hartog, R. H.; Bruijn, M. P.; Clenet, A.; Gottardi, L.; Hijmering, R.; Jackson, B. D.; van der Kuur, J.; van Leeuwen, B. J.; van der Linden, A. J.; van Loon, D.; Nieuwenhuizen, A.; Ridder, M.; van Winden, P.

    2014-08-01

    SRON is developing the electronic read-out for arrays of transition edge sensors using frequency domain multiplexing in combination with base-band feedback. The astronomical applications of this system are the read-out of soft X-ray micro-calorimeters in a potential instrument on the European X-ray mission-under-study Athena+ and far-IR bolometers for the Safari instrument on the Japanese mission SPICA. In this paper we demonstrate the simultaneous read-out of 38 bolometer pixels at a 12 aW/Hz dark NEP level. The stability of the read-out is assessed over 400 s. time spans. Although some 1/f noise is present, there are several bolometers for which 1/f-free read-out can be demonstrated.

  18. Measurement of pixel response functions of a fully depleted CCD

    NASA Astrophysics Data System (ADS)

    Kobayashi, Yukiyasu; Niwa, Yoshito; Yano, Taihei; Gouda, Naoteru; Hara, Takuji; Yamada, Yoshiyuki

    2014-07-01

    We describe the measurement of detailed and precise Pixel Response Functions (PRFs) of a fully depleted CCD. Measurements were performed under different physical conditions, such as different wavelength light sources or CCD operating temperatures. We determined the relations between these physical conditions and the forms of the PRF. We employ two types of PRFs: one is the model PRF (mPRF) that can represent the shape of a PRF with one characteristic parameter and the other is the simulated PRF (sPRF) that is the resultant PRF from simulating physical phenomena. By using measured, model, and simulated PRFs, we determined the relations between operational parameters and the PRFs. Using the obtained relations, we can now estimate a PRF under conditions that will be encountered during the course of Nano-JASMINE observations. These estimated PRFs will be utilized in the analysis of the Nano-JASMINE data.

  19. A semiconductor radiation imaging pixel detector for space radiation dosimetry.

    PubMed

    Kroupa, Martin; Bahadori, Amir; Campbell-Ricketts, Thomas; Empl, Anton; Hoang, Son Minh; Idarraga-Munoz, John; Rios, Ryan; Semones, Edward; Stoffle, Nicholas; Tlustos, Lukas; Turecek, Daniel; Pinsky, Lawrence

    2015-07-01

    Progress in the development of high-performance semiconductor radiation imaging pixel detectors based on technologies developed for use in high-energy physics applications has enabled the development of a completely new generation of compact low-power active dosimeters and area monitors for use in space radiation environments. Such detectors can provide real-time information concerning radiation exposure, along with detailed analysis of the individual particles incident on the active medium. Recent results from the deployment of detectors based on the Timepix from the CERN-based Medipix2 Collaboration on the International Space Station (ISS) are reviewed, along with a glimpse of developments to come. Preliminary results from Orion MPCV Exploration Flight Test 1 are also presented. PMID:26256630

  20. Transillumination imaging through biological tissue by single-pixel detection

    NASA Astrophysics Data System (ADS)

    Durán, Vicente; Soldevila, Fernando; Irles, Esther; Clemente, Pere; Tajahuerce, Enrique; Andrés, Pedro; Lancis, Jesús

    2015-07-01

    One challenge that has long held the attention of scientists is that of clearly seeing objects hidden by turbid media, as smoke, fog or biological tissue, which has major implications in fields such as remote sensing or early diagnosis of diseases. Here, we combine structured incoherent illumination and bucket detection for imaging an absorbing object completely embedded in a scattering medium. A sequence of low-intensity microstructured light patterns is launched onto the object, whose image is accurately reconstructed through the light fluctuations measured by a single-pixel detector. Our technique is noninvasive, does not require coherent sources, raster scanning nor time-gated detection and benefits from the compressive sensing strategy. As a proof of concept, we experimentally retrieve the image of a transilluminated target both sandwiched between two holographic diffusers and embedded in a 6mm-thick sample of chicken breast.

  1. Per-Pixel, Dual-Counter Scheme for Optical Communications

    NASA Technical Reports Server (NTRS)

    Farr, William H.; Bimbaum, Kevin M.; Quirk, Kevin J.; Sburlan, Suzana; Sahasrabudhe, Adit

    2013-01-01

    Free space optical communications links from deep space are projected to fulfill future NASA communication requirements for 2020 and beyond. Accurate laser-beam pointing is required to achieve high data rates at low power levels.This innovation is a per-pixel processing scheme using a pair of three-state digital counters to implement acquisition and tracking of a dim laser beacon transmitted from Earth for pointing control of an interplanetary optical communications system using a focal plane array of single sensitive detectors. It shows how to implement dim beacon acquisition and tracking for an interplanetary optical transceiver with a method that is suitable for both achieving theoretical performance, as well as supporting additional functions of high data rate forward links and precision spacecraft ranging.

  2. Simulation of the dynamic inefficiency of the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Bartók, M.

    2015-05-01

    The Pixel Detector is the innermost part of the CMS Tracker. It therefore has to prevail in the harshest environment in terms of particle fluence and radiation. There are several mechanisms that may decrease the efficiency of the detector. These are mainly caused by data acquisition (DAQ) problems and/or Single Event Upsets (SEU). Any remaining efficiency loss is referred to as the dynamic inefficiency. It is caused by various mechanisms inside the Readout Chip (ROC) and depends strongly on the data occupancy. In the 2012 data, at high values of instantaneous luminosity the inefficiency reached 2% (in the region closest to the interaction point) which is not negligible. In the 2015 run higher instantaneous luminosity is expected, which will result in lower efficiencies; therefore this effect needs to be understood and simulated. A data-driven method has been developed to simulate dynamic inefficiency, which has been shown to successfully simulate the effects.

  3. CMOS Monolithic Active Pixel Sensors (MAPS): Developments and future outlook

    NASA Astrophysics Data System (ADS)

    Turchetta, R.; Fant, A.; Gasiorek, P.; Esbrand, C.; Griffiths, J. A.; Metaxas, M. G.; Royle, G. J.; Speller, R.; Venanzi, C.; van der Stelt, P. F.; Verheij, H.; Li, G.; Theodoridis, S.; Georgiou, H.; Cavouras, D.; Hall, G.; Noy, M.; Jones, J.; Leaver, J.; Machin, D.; Greenwood, S.; Khaleeq, M.; Schulerud, H.; Østby, J. M.; Triantis, F.; Asimidis, A.; Bolanakis, D.; Manthos, N.; Longo, R.; Bergamaschi, A.

    2007-12-01

    Re-invented in the early 1990s, on both sides of the Atlantic, Monolithic Active Pixel Sensors (MAPS) in a CMOS technology are today the most sold solid-state imaging devices, overtaking the traditional technology of Charge-Coupled Devices (CCD). The slow uptake of CMOS MAPS started with low-end applications, for example web-cams, and is slowly pervading the high-end applications, for example in prosumer digital cameras. Higher specifications are required for scientific applications: very low noise, high speed, high dynamic range, large format and radiation hardness are some of these requirements. This paper will present a brief overview of the CMOS Image Sensor technology and of the requirements for scientific applications. As an example, a sensor for X-ray imaging will be presented. This sensor was developed within a European FP6 Consortium, intelligent imaging sensors (I-ImaS).

  4. Spatial optical phase-modulating metadevice with subwavelength pixelation.

    PubMed

    Cencillo-Abad, Pablo; Plum, Eric; Rogers, Edward T F; Zheludev, Nikolay I

    2016-08-01

    Dynamic control over optical wavefronts enables focusing, diffraction and redirection of light on demand, however, sub-wavelength resolution is required to avoid unwanted diffracted beams that are present in commercial spatial light modulators. Here we propose a realistic metadevice that dynamically controls the optical phase of reflected beams with sub-wavelength pixelation in one dimension. Based on reconfigurable metamaterials and nanomembrane technology, it consists of individually moveable metallic nanowire actuators that control the phase of reflected light by modulating the optical path length. We demonstrate that the metadevice can provide on-demand optical wavefront shaping functionalities of diffraction gratings, beam splitters, phase-gradient metasurfaces, cylindrical mirrors and mirror arrays - with variable focal distance and numerical aperture - without unwanted diffraction. PMID:27505842

  5. A semiconductor radiation imaging pixel detector for space radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Kroupa, Martin; Bahadori, Amir; Campbell-Ricketts, Thomas; Empl, Anton; Hoang, Son Minh; Idarraga-Munoz, John; Rios, Ryan; Semones, Edward; Stoffle, Nicholas; Tlustos, Lukas; Turecek, Daniel; Pinsky, Lawrence

    2015-07-01

    Progress in the development of high-performance semiconductor radiation imaging pixel detectors based on technologies developed for use in high-energy physics applications has enabled the development of a completely new generation of compact low-power active dosimeters and area monitors for use in space radiation environments. Such detectors can provide real-time information concerning radiation exposure, along with detailed analysis of the individual particles incident on the active medium. Recent results from the deployment of detectors based on the Timepix from the CERN-based Medipix2 Collaboration on the International Space Station (ISS) are reviewed, along with a glimpse of developments to come. Preliminary results from Orion MPCV Exploration Flight Test 1 are also presented.

  6. High-resolution confocal Raman microscopy using pixel reassignment.

    PubMed

    Roider, Clemens; Ritsch-Marte, Monika; Jesacher, Alexander

    2016-08-15

    We present a practical modification of fiber-coupled confocal Raman scanning microscopes that is able to provide high confocal resolution in conjunction with high light collection efficiency. For this purpose, the single detection fiber is replaced by a hexagonal lenslet array in combination with a hexagonally packed round-to-linear multimode fiber bundle. A multiline detector is used to collect individual Raman spectra for each fiber. Data post-processing based on pixel reassignment allows one to improve the lateral resolution by up to 41% compared to a single fiber of equal light collection efficiency. We present results from an experimental implementation featuring seven collection fibers, yielding a resolution improvement of about 30%. We believe that our implementation represents an attractive upgrade for existing confocal Raman microscopes that employ multi-line detectors. PMID:27519099

  7. Towards a new generation of pixel detector readout chips

    NASA Astrophysics Data System (ADS)

    Campbell, M.; Alozy, J.; Ballabriga, R.; Frojdh, E.; Heijne, E.; Llopart, X.; Poikela, T.; Tlustos, L.; Valerio, P.; Wong, W.

    2016-01-01

    The Medipix3 Collaboration has broken new ground in spectroscopic X-ray imaging and in single particle detection and tracking. This paper will review briefly the performance and limitations of the present generation of pixel detector readout chips developed by the Collaboration. Through Silicon Via technology has the potential to provide a significant improvement in the tile-ability and more flexibility in the choice of readout architecture. This has been explored in the context of 3 projects with CEA-LETI using Medipix3 and Timepix3 wafers. The next generation of chips will aim to provide improved spectroscopic imaging performance at rates compatible with human CT. It will also aim to provide full spectroscopic images with unprecedented energy and spatial resolution. Some of the opportunities and challenges posed by moving to a more dense CMOS process will be discussed.

  8. Monolithic active pixel radiation detector with shielding techniques

    DOEpatents

    Deptuch, Grzegorz W.

    2016-09-06

    A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

  9. Interactive Isogeometric Volume Visualization with Pixel-Accurate Geometry.

    PubMed

    Fuchs, Franz G; Hjelmervik, Jon M

    2016-02-01

    A recent development, called isogeometric analysis, provides a unified approach for design, analysis and optimization of functional products in industry. Traditional volume rendering methods for inspecting the results from the numerical simulations cannot be applied directly to isogeometric models. We present a novel approach for interactive visualization of isogeometric analysis results, ensuring correct, i.e., pixel-accurate geometry of the volume including its bounding surfaces. The entire OpenGL pipeline is used in a multi-stage algorithm leveraging techniques from surface rendering, order-independent transparency, as well as theory and numerical methods for ordinary differential equations. We showcase the efficiency of our approach on different models relevant to industry, ranging from quality inspection of the parametrization of the geometry, to stress analysis in linear elasticity, to visualization of computational fluid dynamics results. PMID:26731454

  10. A Wideband Circularly Polarized Pixelated Dielectric Resonator Antenna.

    PubMed

    Trinh-Van, Son; Yang, Youngoo; Lee, Kang-Yoon; Hwang, Keum Cheol

    2016-01-01

    The design of a wideband circularly polarized pixelated dielectric resonator antenna using a real-coded genetic algorithm (GA) is presented for far-field wireless power transfer applications. The antenna consists of a dielectric resonator (DR) which is discretized into 8 × 8 grid DR bars. The real-coded GA is utilized to estimate the optimal heights of the 64 DR bars to realize circular polarization. The proposed antenna is excited by a narrow rectangular slot etched on the ground plane. A prototype of the proposed antenna is fabricated and tested. The measured -10 dB reflection and 3 dB axial ratio bandwidths are 32.32% (2.62-3.63 GHz) and 14.63% (2.85-3.30 GHz), respectively. A measured peak gain of 6.13 dBic is achieved at 3.2 GHz. PMID:27563897

  11. Nano-fabricated pixelated micropolarizer array for visible imaging polarimetry

    SciTech Connect

    Zhang, Zhigang; Cheng, Teng; Qiu, Kang; Zhang, Qingchuan E-mail: wgchu@nanoctr.cn; Wu, Xiaoping; Dong, Fengliang; Chu, Weiguo E-mail: wgchu@nanoctr.cn

    2014-10-15

    Pixelated micropolarizer array (PMA) is a novel concept for real-time visible imaging polarimetry. A 320 × 240 aluminum PMA fabricated by electron beam lithography is described in this paper. The period, duty ratio, and depth of the grating are 140 nm, 0.5, and 100 nm, respectively. The units are standard square structures and the metal nanowires of the grating are collimating and uniformly thick. The extinction ratio of 75 and the maximum polarization transmittance of 78.8% demonstrate that the PMA is suitable for polarization imaging. When the PMA is applied to real-time polarization imaging, the degree of linear polarization image and the angle of linear polarization image are calculated from a single frame image. The polarized target object is highlighted from the unpolarized background, and the surface contour of the target object can be reflected by the polarization angle.

  12. Improving class separability using extended pixel planes: a comparative study

    PubMed Central

    Orlov, Nikita V.; Eckley, D. Mark; Shamir, Lior; Goldberg, Ilya G.

    2011-01-01

    In this work we explored class separability in feature spaces built on extended representations of pixel planes (EPP) produced using scale pyramid, subband pyramid, and image transforms. The image transforms included Chebyshev, Fourier, wavelets, gradient and Laplacian; we also utilized transform combinations, including Fourier, Chebyshev and wavelets of the gradient transform, as well as Fourier of the Laplacian transform. We demonstrate that all three types of EPP promote class separation. We also explored the effect of EPP on suboptimal feature libraries, using only textural features in one case and only Haralick features in another. The effect of EPP was especially clear for these suboptimal libraries, where the transform-based representations were found to increase separability to a greater extent than scale or subband pyramids. EPP can be particularly useful in new applications where optimal features have not yet been developed. PMID:23074356

  13. Correcting saturated pixels in images based on human visual characteristics

    NASA Astrophysics Data System (ADS)

    Fu, Jun; Peng, Hui; Chen, Xi; Mou, Xuanqin

    2013-01-01

    This paper presents a correcting method for saturated images which is operated in the YCbCr color space. The algorithm is based on two human visual characteristics, one is the visual sensitivities to color differences and the other is the Hunt effect. During the process of correcting colors, MacAdam ellipse model mapped to the YCbCr color space is used to search the nearest color. And during the process of the quantification of the YCbCr components for digital implementation, the regions with high luminance are set to have less saturation based on the Hunt effect. Experimental results show that the proposed method is more effective in correcting saturated pixels, especially for the optimization of the region with less luminance and more colorfulness.

  14. Hybrid mimics and hybrid vigor in Arabidopsis

    PubMed Central

    Wang, Li; Greaves, Ian K.; Groszmann, Michael; Wu, Li Min; Dennis, Elizabeth S.; Peacock, W. James

    2015-01-01

    F1 hybrids can outperform their parents in yield and vegetative biomass, features of hybrid vigor that form the basis of the hybrid seed industry. The yield advantage of the F1 is lost in the F2 and subsequent generations. In Arabidopsis, from F2 plants that have a F1-like phenotype, we have by recurrent selection produced pure breeding F5/F6 lines, hybrid mimics, in which the characteristics of the F1 hybrid are stabilized. These hybrid mimic lines, like the F1 hybrid, have larger leaves than the parent plant, and the leaves have increased photosynthetic cell numbers, and in some lines, increased size of cells, suggesting an increased supply of photosynthate. A comparison of the differentially expressed genes in the F1 hybrid with those of eight hybrid mimic lines identified metabolic pathways altered in both; these pathways include down-regulation of defense response pathways and altered abiotic response pathways. F6 hybrid mimic lines are mostly homozygous at each locus in the genome and yet retain the large F1-like phenotype. Many alleles in the F6 plants, when they are homozygous, have expression levels different to the level in the parent. We consider this altered expression to be a consequence of transregulation of genes from one parent by genes from the other parent. Transregulation could also arise from epigenetic modifications in the F1. The pure breeding hybrid mimics have been valuable in probing the mechanisms of hybrid vigor and may also prove to be useful hybrid vigor equivalents in agriculture. PMID:26283378

  15. MOSAD IR focal plane per pixel A/D development

    NASA Astrophysics Data System (ADS)

    Mandl, William J.; Kennedy, James J.; Chu, Muren

    1996-06-01

    An on focal plane digital readout development suggested by the Army Night Vision & Electronics Sensors Directorate is proceeding under a combined program with the development of two color HCT detector arrays. The on focal plane A/D process is based on the Amain patented multiplexed oversample A/D, MOSAD, technology. In the first year of the program, prototype on focal plane analog to digital converters for both staring arrays and scanning arrays were built and demonstrated. The prototypes included a 2 loop double ended switched MOSAD and a 1 loop single ended MOSAD. Results from the original experimental prototypes showed conclusively that better than 14 bits could be achieved and that well capacity could be increased to support high background HCT needs approaching 10(superscript 9) electrons. In the second year, a 64 X 64 staring array for HCT LWIR detectors, 50 micron centers, was built based on these original prototype designs. The layout of the per pixel MOSAD A/D staring array used Orbit 1.2 micron CMOS process and achieved a pixel size of 40 microns with a well capacity of 1.9 X 10(superscript 8) electrons. Integration capacitors were built using Orbit's normal double poly capacitors with a standard buffered direct inject TIA detector interface configuration. Preliminary testing has been completed indicating complete functionality. Fermionics LWIR HCT detectors with cutoff at 9 microns have been built for attachment to the readout but indium bumping was not completed in time to report system level testing results. However, some noise tests have been performed using on array current mirrors. These tests indicate that better than 12 bits has been achieved, but lower noise current sources will be required for a more accurate measurement.

  16. Signal processing algorithms for staring single pixel hyperspectral sensors

    NASA Astrophysics Data System (ADS)

    Manolakis, Dimitris; Rossacci, Michael; O'Donnell, Erin; D'Amico, Francis M.

    2006-08-01

    Remote sensing of chemical warfare agents (CWA) with stand-off hyperspectral sensors has a wide range of civilian and military applications. These sensors exploit the spectral changes in the ambient photon flux produced thermal emission or absorption after passage through a region containing the CWA cloud. In this work we focus on (a) staring single-pixel sensors that sample their field of view at regular intervals of time to produce a time series of spectra and (b) scanning single or multiple pixel sensors that sample their FOV as they scan. The main objective of signal processing algorithms is to determine if and when a CWA enters the FOV of the sensor. We shall first develop and evaluate algorithms for staring sensors following two different approaches. First, we will assume that no threat information is available and we design an adaptive anomaly detection algorithm to detect a statistically-significant change in the observed spectrum. The algorithm processes the observed spectra sequentially-in-time, estimates adaptively the background, and checks whether the next spectrum differs significantly from the background based on the Mahalanobis distance or the distance from the background subspace. In the second approach, we will assume that we know the spectral signature of the CWA and develop sequential-in-time adaptive matched filter detectors. In both cases, we assume that the sensor starts its operation before the release of the CWA; otherwise, staring at a nearby CWA-free area is required for background estimation. Experimental evaluation and comparison of the proposed algorithms is accomplished using data from a long-wave infrared (LWIR) Fourier transform spectrometer.

  17. The data acquisition system of the Belle II Pixel Detector

    NASA Astrophysics Data System (ADS)

    Münchow, D.; Dingfelder, J.; Geßler, T.; Konorov, I.; Kühn, W.; Lange, S.; Lautenbach, K.; Levit, D.; Liu, Z.; Marinas, C.; Schnell, M.; Spruck, B.; Zhao, J.

    2014-08-01

    At the future Belle II experiment the DEPFET (DEPleted Field Effect Transistor) pixel detector will consist of about 8 million channels and is placed as the innermost detector. Because of its small distance to the interaction region and the high luminosity in Belle II, for a trigger rate of about 30 kHz with an estimated occupancy of about 3 % a data rate of about 22 GB/s is expected. Due to the high data rate, a data reduction factor higher than 30 is needed in order to stay inside the specifications of the event builder. The main hardware to reduce the data rate is a xTCA based Compute Node (CN) developed in cooperation between IHEP Beijing and University Giessen. Each node has as main component a Xilinx Virtex-5 FX70T FPGA and is equipped with 2 × 2 GB RAM , GBit Ethernet and 4 × 6.25 Gb/s optical links. An ATCA carrier board is able to hold up to four CN and supplies high bandwidth connections between the four CNs and to the ATCA backplane. To achieve the required data reduction on the CNs, regions of interest (ROI) are used. These regions are calculated in two independent systems by projecting tracks back to the pixel detector. One is the High Level Trigger (HLT) which uses data from the Silicon Vertex Detector (SVD), a silicon strip detector, and outer detectors. The other is the Data Concentrator (DATCON) which calculates ROIs based on SVD data only, in order to get low momentum tracks. With this information, only PXD data inside these ROIs will be forwarded to the event builder, while data outside of these regions will be discarded. First results of the test beam time in January 2014 at DESY with a Belle II vertex detector prototype and full DAQ chain will be presented.

  18. 2D Sub-Pixel Disparity Measurement Using QPEC / Medicis

    NASA Astrophysics Data System (ADS)

    Cournet, M.; Giros, A.; Dumas, L.; Delvit, J. M.; Greslou, D.; Languille, F.; Blanchet, G.; May, S.; Michel, J.

    2016-06-01

    In the frame of its earth observation missions, CNES created a library called QPEC, and one of its launcher called Medicis. QPEC / Medicis is a sub-pixel two-dimensional stereo matching algorithm that works on an image pair. This tool is a block matching algorithm, which means that it is based on a local method. Moreover it does not regularize the results found. It proposes several matching costs, such as the Zero mean Normalised Cross-Correlation or statistical measures (the Mutual Information being one of them), and different match validation flags. QPEC / Medicis is able to compute a two-dimensional dense disparity map with a subpixel precision. Hence, it is more versatile than disparity estimation methods found in computer vision literature, which often assume an epipolar geometry. CNES uses Medicis, among other applications, during the in-orbit image quality commissioning of earth observation satellites. For instance the Pléiades-HR 1A & 1B and the Sentinel-2 geometric calibrations are based on this block matching algorithm. Over the years, it has become a common tool in ground segments for in-flight monitoring purposes. For these two kinds of applications, the two-dimensional search and the local sub-pixel measure without regularization can be essential. This tool is also used to generate automatic digital elevation models, for which it was not initially dedicated. This paper deals with the QPEC / Medicis algorithm. It also presents some of its CNES applications (in-orbit commissioning, in flight monitoring or digital elevation model generation). Medicis software is distributed outside the CNES as well. This paper finally describes some of these external applications using Medicis, such as ground displacement measurement, or intra-oral scanner in the dental domain.

  19. Urban Image Classification: Per-Pixel Classifiers, Sub-Pixel Analysis, Object-Based Image Analysis, and Geospatial Methods. 10; Chapter

    NASA Technical Reports Server (NTRS)

    Myint, Soe W.; Mesev, Victor; Quattrochi, Dale; Wentz, Elizabeth A.

    2013-01-01

    Remote sensing methods used to generate base maps to analyze the urban environment rely predominantly on digital sensor data from space-borne platforms. This is due in part from new sources of high spatial resolution data covering the globe, a variety of multispectral and multitemporal sources, sophisticated statistical and geospatial methods, and compatibility with GIS data sources and methods. The goal of this chapter is to review the four groups of classification methods for digital sensor data from space-borne platforms; per-pixel, sub-pixel, object-based (spatial-based), and geospatial methods. Per-pixel methods are widely used methods that classify pixels into distinct categories based solely on the spectral and ancillary information within that pixel. They are used for simple calculations of environmental indices (e.g., NDVI) to sophisticated expert systems to assign urban land covers. Researchers recognize however, that even with the smallest pixel size the spectral information within a pixel is really a combination of multiple urban surfaces. Sub-pixel classification methods therefore aim to statistically quantify the mixture of surfaces to improve overall classification accuracy. While within pixel variations exist, there is also significant evidence that groups of nearby pixels have similar spectral information and therefore belong to the same classification category. Object-oriented methods have emerged that group pixels prior to classification based on spectral similarity and spatial proximity. Classification accuracy using object-based methods show significant success and promise for numerous urban 3 applications. Like the object-oriented methods that recognize the importance of spatial proximity, geospatial methods for urban mapping also utilize neighboring pixels in the classification process. The primary difference though is that geostatistical methods (e.g., spatial autocorrelation methods) are utilized during both the pre- and post

  20. IV and CV curves for irradiated prototype BTeV silicon pixel sensors

    SciTech Connect

    Maria R. Coluccia et al.

    2002-07-16

    The authors present IV and CV curves for irradiated prototype n{sup +}/n/p{sup +} silicon pixel sensors, intended for use in the BTeV experiment at Fermilab. They tested pixel sensors from various vendors and with two pixel isolation layouts: p-stop and p-spray. Results are based on exposure with 200 MeV protons up to 6 x 10{sup 14} protons/cm{sup 2}.

  1. Electronic holographic device based on macro-pixel with local coherence

    NASA Astrophysics Data System (ADS)

    Moon, Woonchan; Kwon, Jaebeom; Kim, Hwi; Hahn, Joonku

    2015-09-01

    Holography has been regarded as one of the most ideal technique for three-dimensional (3D) display because it records and reconstructs both amplitude and phase of object wave simultaneously. Nevertheless, many people think that this technique is not suitable for commercialization due to some significant problems. In this paper, we propose an electronic holographic 3D display based on macro-pixel with local coherence. Here, the incident wave within each macro-pixel is coherent but the wave in one macro-pixel is not mutually coherent with the wave in the other macro-pixel. This concept provides amazing freedom in distribution of the pixels in modulator. The relative distance between two macro-pixels results in negligible change of interference pattern in observation space. Also it is possible to make the sub-pixels in a macro-pixel in order to enlarge the field of view (FOV). The idea has amazing effects to reduce the data capacity of the holographic display. Moreover, the dimension of the system is can be remarkably downsized by micro-optics. As a result, the holographic display will be designed to have full parallax with large FOV and screen size. We think that the macro-pixel idea is a practical solution in electronic holography since it can provide reasonable FOV and large screen size with relatively small amount of data.

  2. Error analysis of filtering operations in pixel-duplicated images of diabetic retinopathy

    NASA Astrophysics Data System (ADS)

    Mehrubeoglu, Mehrube; McLauchlan, Lifford

    2010-08-01

    In this paper, diabetic retinopathy is chosen for a sample target image to demonstrate the effectiveness of image enlargement through pixel duplication in identifying regions of interest. Pixel duplication is presented as a simpler alternative to data interpolation techniques for detecting small structures in the images. A comparative analysis is performed on different image processing schemes applied to both original and pixel-duplicated images. Structures of interest are detected and and classification parameters optimized for minimum false positive detection in the original and enlarged retinal pictures. The error analysis demonstrates the advantages as well as shortcomings of pixel duplication in image enhancement when spatial averaging operations (smoothing filters) are also applied.

  3. Denoising of brain MRI images using modified PDE based on pixel similarity

    NASA Astrophysics Data System (ADS)

    Jin, Renchao; Song, Enmin; Zhang, Lijuan; Min, Zhifang; Xu, Xiangyang; Huang, Chih-Cheng

    2008-03-01

    Although various image denoising methods such as PDE-based algorithms have made remarkable progress in the past years, the trade-off between noise reduction and edge preservation is still an interesting and difficult problem in the field of image processing and analysis. A new image denoising algorithm, using a modified PDE model based on pixel similarity, is proposed to deal with the problem. The pixel similarity measures the similarity between two pixels. Then the neighboring consistency of the center pixel can be calculated. Informally, if a pixel is not consistent enough with its surrounding pixels, it can be considered as a noise, but an extremely strong inconsistency suggests an edge. The pixel similarity is a probability measure, its value is between 0 and 1. According to the neighboring consistency of the pixel, a diffusion control factor can be determined by a simple thresholding rule. The factor is combined into the primary partial differential equation as an adjusting factor for controlling the speed of diffusion for different type of pixels. An evaluation of the proposed algorithm on the simulated brain MRI images was carried out. The initial experimental results showed that the new algorithm can smooth the MRI images better while keeping the edges better and achieve higher peak signal to noise ratio (PSNR) comparing with several existing denoising algorithms.

  4. Characterization of Pixelated Cadmium-Zinc-Telluride Detectors for Astrophysical Applications

    NASA Technical Reports Server (NTRS)

    Gaskin, Jessica; Sharma, Dharma; Ramsey, Brian; Seller, Paul

    2003-01-01

    Comparisons of charge sharing and charge loss measurements between two pixelated Cadmium-Zinc-Telluride (CdZnTe) detectors are discussed. These properties along with the detector geometry help to define the limiting energy resolution and spatial resolution of the detector in question. The first detector consists of a 1-mm-thick piece of CdZnTe sputtered with a 4x4 array of pixels with pixel pitch of 750 microns (inter-pixel gap is 100 microns). Signal readout is via discrete ultra-low-noise preamplifiers, one for each of the 16 pixels. The second detector consists of a 2-mm-thick piece of CdZnTe sputtered with a 16x16 array of pixels with a pixel pitch of 300 microns (inter-pixel gap is 50 microns). This crystal is bonded to a custom-built readout chip (ASIC) providing all front-end electronics to each of the 256 independent pixels. These detectors act as precursors to that which will be used at the focal plane of the High Energy Replicated Optics (HERO) telescope currently being developed at Marshall Space Flight Center. With a telescope focal length of 6 meters, the detector needs to have a spatial resolution of around 200 microns in order to take full advantage of the HERO angular resolution. We discuss to what degree charge sharing will degrade energy resolution but will improve our spatial resolution through position interpolation.

  5. A high fill-factor low dark leakage CMOS image sensor with shared-pixel design

    NASA Astrophysics Data System (ADS)

    Seo, Min-Woong; Yasutomi, Keita; Kagawa, Keiichiro; Kawahito, Shoji

    2014-03-01

    We have developed and evaluated the high responsivity and low dark leakage CMOS image sensor with the ring-gate shared-pixel design. A ring-gate shared-pixel design with a high fill factor makes it possible to achieve the low-light imaging. As eliminating the shallow trench isolation in the proposed pixel, the dark leakage current is significantly decreased because one of major dark leakage sources is removed. By sharing the in-pixel transistors such as a reset transistor, a select transistor, and a source follower amplifier, each pixel has a high fill-factor of 43 % and high sensitivity of 144.6 ke-/lx·sec. In addition, the effective number of transistors per pixel is 1.75. The proposed imager achieved the relatively low dark leakage current of about 104.5 e-/s (median at 60°C), corresponding to a dark current density Jdark_proposed of about 30 pA/cm2. In contrast, the conventional type test pixel has a large dark leakage current of 2450 e-/s (median at 60°C), corresponding to Jdark_conventional of about 700 pA/cm2. Both pixels have a same pixel size of 7.5×7.5 μm2 and are fabricated in same process.

  6. 1T Pixel Using Floating-Body MOSFET for CMOS Image Sensors

    PubMed Central

    Lu, Guo-Neng; Tournier, Arnaud; Roy, François; Deschamps, Benoît

    2009-01-01

    We present a single-transistor pixel for CMOS image sensors (CIS). It is a floating-body MOSFET structure, which is used as photo-sensing device and source-follower transistor, and can be controlled to store and evacuate charges. Our investigation into this 1T pixel structure includes modeling to obtain analytical description of conversion gain. Model validation has been done by comparing theoretical predictions and experimental results. On the other hand, the 1T pixel structure has been implemented in different configurations, including rectangular-gate and ring-gate designs, and variations of oxidation parameters for the fabrication process. The pixel characteristics are presented and discussed. PMID:22389592

  7. Reducing the effect of pixel crosstalk in phase only spatial light modulators.

    PubMed

    Persson, Martin; Engström, David; Goksör, Mattias

    2012-09-24

    A method for compensating for pixel crosstalk in liquid crystal based spatial light modulators is presented. By modifying a commonly used hologram generating algorithm to account for pixel crosstalk, the intensity errors in obtained diffraction spot intensities are significantly reduced. We also introduce a novel method for characterizing the pixel crosstalk in phase-only spatial light modulators, providing input for the hologram generating algorithm. The methods are experimentally evaluated and an improvement of the spot uniformity by more than 100% is demonstrated for an SLM with large pixel crosstalk. PMID:23037382

  8. Supervised pixel classification using a feature space derived from an artificial visual system

    NASA Technical Reports Server (NTRS)

    Baxter, Lisa C.; Coggins, James M.

    1991-01-01

    Image segmentation involves labelling pixels according to their membership in image regions. This requires the understanding of what a region is. Using supervised pixel classification, the paper investigates how groups of pixels labelled manually according to perceived image semantics map onto the feature space created by an Artificial Visual System. Multiscale structure of regions are investigated and it is shown that pixels form clusters based on their geometric roles in the image intensity function, not by image semantics. A tentative abstract definition of a 'region' is proposed based on this behavior.

  9. Methodological Study of a Single Photon Counting Pixel Detector at SPring-8

    SciTech Connect

    Toyokawa, H.; Suzuki, M.; Broennimann, Ch.; Eikenberry, E. F.; Henrich, B.; Huelsen, G.; Kraft, P.

    2007-01-19

    PILATUS (Pixel Apparatus for the SLS) is a challenging project to develop a large area single photon counting pixel detector for synchrotron radiation experiments. SPring-8 examined the PLATUS single module detectors in collaboration with the Paul Scherrer Institute. The PILATUS-II single module detector has a desired performance with almost zero defective pixels and a fast frame rate up to 100 Hz using a newly developed PCI readout system on a Linux-PC. The maximum counting rate achieves more than 2 x 106 X-rays/s/pixel.

  10. Increased space-bandwidth product in pixel super-resolved lensfree on-chip microscopy

    NASA Astrophysics Data System (ADS)

    Greenbaum, Alon; Luo, Wei; Khademhosseinieh, Bahar; Su, Ting-Wei; Coskun, Ahmet F.; Ozcan, Aydogan

    2013-04-01

    Pixel-size limitation of lensfree on-chip microscopy can be circumvented by utilizing pixel-super-resolution techniques to synthesize a smaller effective pixel, improving the resolution. Here we report that by using the two-dimensional pixel-function of an image sensor-array as an input to lensfree image reconstruction, pixel-super-resolution can improve the numerical aperture of the reconstructed image by ~3 fold compared to a raw lensfree image. This improvement was confirmed using two different sensor-arrays that significantly vary in their pixel-sizes, circuit architectures and digital/optical readout mechanisms, empirically pointing to roughly the same space-bandwidth improvement factor regardless of the sensor-array employed in our set-up. Furthermore, such a pixel-count increase also renders our on-chip microscope into a Giga-pixel imager, where an effective pixel count of ~1.6-2.5 billion can be obtained with different sensors. Finally, using an ultra-violet light-emitting-diode, this platform resolves 225 nm grating lines and can be useful for wide-field on-chip imaging of nano-scale objects, e.g., multi-walled-carbon-nanotubes.

  11. Fast Contour-Tracing Algorithm Based on a Pixel-Following Method for Image Sensors.

    PubMed

    Seo, Jonghoon; Chae, Seungho; Shim, Jinwook; Kim, Dongchul; Cheong, Cheolho; Han, Tack-Don

    2016-01-01

    Contour pixels distinguish objects from the background. Tracing and extracting contour pixels are widely used for smart/wearable image sensor devices, because these are simple and useful for detecting objects. In this paper, we present a novel contour-tracing algorithm for fast and accurate contour following. The proposed algorithm classifies the type of contour pixel, based on its local pattern. Then, it traces the next contour using the previous pixel's type. Therefore, it can classify the type of contour pixels as a straight line, inner corner, outer corner and inner-outer corner, and it can extract pixels of a specific contour type. Moreover, it can trace contour pixels rapidly because it can determine the local minimal path using the contour case. In addition, the proposed algorithm is capable of the compressing data of contour pixels using the representative points and inner-outer corner points, and it can accurately restore the contour image from the data. To compare the performance of the proposed algorithm to that of conventional techniques, we measure their processing time and accuracy. In the experimental results, the proposed algorithm shows better performance compared to the others. Furthermore, it can provide the compressed data of contour pixels and restore them accurately, including the inner-outer corner, which cannot be restored using conventional algorithms. PMID:27005632

  12. Increased space-bandwidth product in pixel super-resolved lensfree on-chip microscopy

    PubMed Central

    Greenbaum, Alon; Luo, Wei; Khademhosseinieh, Bahar; Su, Ting-Wei; Coskun, Ahmet F.; Ozcan, Aydogan

    2013-01-01

    Pixel-size limitation of lensfree on-chip microscopy can be circumvented by utilizing pixel-super-resolution techniques to synthesize a smaller effective pixel, improving the resolution. Here we report that by using the two-dimensional pixel-function of an image sensor-array as an input to lensfree image reconstruction, pixel-super-resolution can improve the numerical aperture of the reconstructed image by ~3 fold compared to a raw lensfree image. This improvement was confirmed using two different sensor-arrays that significantly vary in their pixel-sizes, circuit architectures and digital/optical readout mechanisms, empirically pointing to roughly the same space-bandwidth improvement factor regardless of the sensor-array employed in our set-up. Furthermore, such a pixel-count increase also renders our on-chip microscope into a Giga-pixel imager, where an effective pixel count of ~1.6–2.5 billion can be obtained with different sensors. Finally, using an ultra-violet light-emitting-diode, this platform resolves 225 nm grating lines and can be useful for wide-field on-chip imaging of nano-scale objects, e.g., multi-walled-carbon-nanotubes.

  13. 1T Pixel Using Floating-Body MOSFET for CMOS Image Sensors.

    PubMed

    Lu, Guo-Neng; Tournier, Arnaud; Roy, François; Deschamps, Benoît

    2009-01-01

    We present a single-transistor pixel for CMOS image sensors (CIS). It is a floating-body MOSFET structure, which is used as photo-sensing device and source-follower transistor, and can be controlled to store and evacuate charges. Our investigation into this 1T pixel structure includes modeling to obtain analytical description of conversion gain. Model validation has been done by comparing theoretical predictions and experimental results. On the other hand, the 1T pixel structure has been implemented in different configurations, including rectangular-gate and ring-gate designs, and variations of oxidation parameters for the fabrication process. The pixel characteristics are presented and discussed. PMID:22389592

  14. GENIE: a hybrid genetic algorithm for feature classification in multispectral images

    NASA Astrophysics Data System (ADS)

    Perkins, Simon J.; Theiler, James P.; Brumby, Steven P.; Harvey, Neal R.; Porter, Reid B.; Szymanski, John J.; Bloch, Jeffrey J.

    2000-10-01

    We consider the problem of pixel-by-pixel classification of a multi- spectral image using supervised learning. Conventional spuervised classification techniques such as maximum likelihood classification and less conventional ones s uch as neural networks, typically base such classifications solely on the spectral components of each pixel. It is easy to see why: the color of a pixel provides a nice, bounded, fixed dimensional space in which these classifiers work well. It is often the case however, that spectral information alone is not sufficient to correctly classify a pixel. Maybe spatial neighborhood information is required as well. Or maybe the raw spectral components do not themselves make for easy classification, but some arithmetic combination of them would. In either of these cases we have the problem of selecting suitable spatial, spectral or spatio-spectral features that allow the classifier to do its job well. The number of all possible such features is extremely large. How can we select a suitable subset? We have developed GENIE, a hybrid learning system that combines a genetic algorithm that searches a space of image processing operations for a set that can produce suitable feature planes, and a more conventional classifier which uses those feature planes to output a final classification. In this paper we show that the use of a hybrid GA provides significant advantages over using either a GA alone or more conventional classification methods alone. We present results using high-resolution IKONOS data, looking for regions of burned forest and for roads.

  15. GENIE: A HYBRID GENETIC ALGORITHM FOR FEATURE CLASSIFICATION IN MULTI-SPECTRAL IMAGES

    SciTech Connect

    S. PERKINS; ET AL

    2000-12-01

    We consider the problem of pixel-by-pixel classification of a multi-spectral image using supervised learning. Conventional supervised classification techniques such as maximum likelihood classification and less conventional ones such as neural networks, typically base such classifications solely on the spectral components of each pixel. It is easy to see why the color of a pixel provides a nice, bounded, fixed dimensional space in which these classifiers work well. It is often the case however, that spectral information alone is not sufficient to correctly classify a pixel. Maybe spatial neighborhood information is required as well. Or may be the raw spectral components do not themselves make for easy classification, but some arithmetic combination of them would. In either of these cases we have the problem of selecting suitable spatial, spectral or spatio-spectral features that allow the classifier to do its job well. The number of all possible such features is extremely large. How can we select a suitable subset? We have developed GENIE, a hybrid learning system that combines a genetic algorithm that searches a space of image processing operations for a set that can produce suitable feature planes, and a more conventional classifier which uses those feature planes to output a final classification. In this paper we show that the use of a hybrid GA provides significant advantages over using either a GA alone or more conventional classification methods alone. We present results using high-resolution IKONOS data, looking for regions of burned forest and for roads.

  16. Improved volcanic ash detection based on a hybrid reverse absorption technique

    NASA Astrophysics Data System (ADS)

    Lee, Kwon Ho; Wong, Man Sing; Chung, Sung-Rae; Sohn, Eunha

    2014-06-01

    A noble volcanic ash (VA) detection method based on a hybrid reverse absorption technique was successfully applied in the analysis of major volcanic eruptions that occurred in Russia, Iceland, Chile, Italy, and Japan by using the MODerate-resolution Imaging Spectroradiometer (MODIS) observation data. Sensitivity studies using radiative-transfer simulations by using various environmental parameters such as ash loadings, sizes, layer heights, and surface emissions, revealed that VA effects on brightness temperatures (BT) can reach up to 40 K. The advantage of the hybrid algorithm is its ability to detect distinct VA pixels during the day and night from satellite observations. The results showed that the hybrid algorithm can minimize the false detection of VA pixels, while well-known reverse absorption methods show abundant false VA pixels over bright surfaces and cloud formations. Further, the time-and-space distribution of the VA pixels is in good agreement with the data pertaining to operational aerosol products obtained from the scanning imaging absorption spectrometer for atmospheric cartography (SCIAMACHY) instrument on board ESA's Envisat and the cloud-aerosol Lidar and infrared pathfinder satellite observations (CALIPSO). This novel algorithm is expected to provide a fine spatial and temporal resolution of VA monitoring from high spectral or geostationary satellite observation data.

  17. The Speedster-EXD - A New Event-Triggered Hybrid CMOS X-ray Detector

    NASA Astrophysics Data System (ADS)

    Griffith, Christopher; Falcone, Abraham; Prieskorn, Zachary; Burrows, David N.

    2014-08-01

    We present the characterization of a new event driven x-ray hybrid CMOS detector developed by Teledyne imaging Sensors in collaboration with Penn State University. Hybrid CMOS detectors currently have many advantages over CCD’s including lower susceptibility to radiation damage, lower power consumption, and faster read-out time to avoid pile-up. The Speedster-EXD includes an in-pixel comparator that enables read out of only the pixels with signal from an x-ray event. The comparator threshold can be set by the user and only pixels with signal above this threshold are read out. This event-driven readout feature can increase effective frame rates by orders of magnitude, enabling future x-ray missions. The Speedster-EXD hybrid CMOS detector also has additional features that improve upon our previous generation of detectors including: (1) a low-noise, high-gain CTIA amplifier to eliminate interpixel capacitance crosstalk, (2) four different gain modes to optimize either full well capacity or energy resolution, and (3) in-pixel CDS subtraction to reduce read noise. We present the read noise, dark current, interpixel capacitance, energy resolution, and gain variation measurements of the Speedster-EXD detector.

  18. The Speedster-EXD - A New Event-Triggered Hybrid CMOS X-ray Detector

    NASA Astrophysics Data System (ADS)

    Griffith, Christopher; Falcone, A.; Prieskorn, Z.; Burrows, D. N.

    2014-01-01

    We report on the development of a new Teledyne Imaging Systems hybrid CMOS x-ray detector called the Speedster-EXD which is capable of event-triggered read-out. Hybrid CMOS detectors currently have many advantages over CCDs including lower susceptibility to radiation damage, lower power consumption, and faster read out time to avoid pile-up. In addition to these advantages, the Speedster-EXD has new in-pixel circuitry which includes CDS subtraction to reduce read noise and a CTIA amplifier to eliminate interpixel capacitance crosstalk. The new circuitry also includes an in-pixel comparator that triggers on x-ray events. The comparator feature allows the detector to only read pixels in which an x-ray is detected. This feature increases the detector array effective frame rate by orders of magnitude. The current advantages of hybrid CMOS x-ray detectors combined with the new in-pixel circuitry makes the Speedster-EXD an ideal candidate for future high throughput x-ray missions requiring large-format silicon imagers.

  19. Measurements of Si hybrid CMOS x-ray detector characteristics

    NASA Astrophysics Data System (ADS)

    Bongiorno, Stephen D.; Falcone, Abraham D.; Burrows, David N.; Cook, Robert

    2010-07-01

    The recent development of active pixel sensors as X-Ray focal plane arrays will place them in contention with CCDs on future satellite missions. Penn State University (PSU) is working with Teledyne Imaging Sensors (TIS) to develop X-Ray Hybrid CMOS devices (HCDs), a type of active pixel sensor with fast frame rates, adaptable readout timing and geometry, low power consumption, and inherent radiation hardness. CCDs have been used with great success on the current generation of X-Ray telescopes (e.g. Chandra, XMM, Suzaku, and Swift). However, their bucket-brigade readout architecture, which transfers charge across the chip with discrete component readout electronics, results in clockrate limited readout speeds that cause pileup (saturation) of bright sources and an inherent susceptibility to radiation induced displacement damage that limits mission lifetime. In contrast, HCDs read pixels through the detector substrate with low power, on-chip readout integrated circuits. Faster frame rates, achieved with adaptable readout timing and geometry, will allow the next generation's larger effective area telescopes to observe brighter sources free of pileup. In HCDs, radiation damaged lattice sites affect a single pixel instead of an entire row. The PSU X-ray group is currently testing 4 Teledyne HCDs, with low cross-talk CTIA devices in development. We will report laboratory measurements of HCD readnoise, interpixel-capacitance and its impact on event selection, linearity, and energy resolution as a function of energy.

  20. A 12-bit 60-MS/s 36-mW SHA-less opamp-sharing pipeline ADC in 130 nm CMOS

    NASA Astrophysics Data System (ADS)

    Wen, X.; Chen, J.; You, Y.; Feng, Y.; Tang, Y.; Zuo, Z.; Vosooghi, B.; Fan, Q.; Xiao, L.; Gong, D.; Liu, T.; Ye, J.

    2016-01-01

    This paper presents a 12-bit 60-MS/s SHA-less opamp-sharing pipeline analog-to-digital converter (ADC) implemented in a 0.13-μ m CMOS technology. A switch-embedded dual-input current-reused operational transconductance amplifier (OTA) with an overlapping two-phase clocking scheme is proposed to achieve low power consumption and eliminate the non-resetting and memory effects observed in conventional opamp-sharing techniques. To further reduce the power consumption, the ADC also incorporates a SHA-less multi-bit structure. The ADC achieves a signal-to-noise and distortion ratio of 64.9 dB and a spurious-free dynamic range of 77.1 dB at 60 MS/s. It occupies 2.3 mm 2 of area and consumes 36 mW of power under a 1.2-V supply.