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Sample records for pixelated lso array

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-09

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

  2. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    Science.gov (United States)

    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. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    Science.gov (United States)

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

    2017-01-01

    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.

  4. A sub-millimeter resolution PET detector module using a multi-pixel photon counter array.

    Science.gov (United States)

    Song, Tae Yong; Wu, Heyu; Komarov, Sergey; Siegel, Stefan B; Tai, Yuan-Chuan

    2010-05-07

    A PET block detector module using an array of sub-millimeter lutetium oxyorthosilicate (LSO) crystals read out by an array of surface-mount, semiconductor photosensors has been developed. The detector consists of a LSO array, a custom acrylic light guide, a 3 x 3 multi-pixel photon counter (MPPC) array (S10362-11-050P, Hamamatsu Photonics, Japan) and a readout board with a charge division resistor network. The LSO array consists of 100 crystals, each measuring 0.8 x 0.8 x 3 mm(3) and arranged in 0.86 mm pitches. A Monte Carlo simulation was used to aid the design and fabrication of a custom light guide to control distribution of scintillation light over the surface of the MPPC array. The output signals of the nine MPPC are multiplexed by a charge division resistor network to generate four position-encoded analog outputs. Flood image, energy resolution and timing resolution measurements were performed using standard NIM electronics. The linearity of the detector response was investigated using gamma-ray sources of different energies. The 10 x 10 array of 0.8 mm LSO crystals was clearly resolved in the flood image. The average energy resolution and standard deviation were 20.0% full-width at half-maximum (FWHM) and +/-5.0%, respectively, at 511 keV. The timing resolution of a single MPPC coupled to a LSO crystal was found to be 857 ps FWHM, and the value for the central region of detector module was 1182 ps FWHM when +/-10% energy window was applied. The nonlinear response of a single MPPC when used to read out a single LSO was observed among the corner crystals of the proposed detector module. However, the central region of the detector module exhibits significantly less nonlinearity (6.5% for 511 keV). These results demonstrate that (1) a charge-sharing resistor network can effectively multiplex MPPC signals and reduce the number of output signals without significantly degrading the performance of a PET detector and (2) a custom light guide to permit light sharing

  5. ISPA (imaging silicon pixel array) experiment

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    The bump-bonded silicon pixel detector, developed at CERN by the EP-MIC group, is shown here in its ceramic carrier. Both represent the ISPA-tube anode. The chip features between 1024 (called OMEGA-1) and 8196 (ALICE-1) active pixels.

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

    Energy Technology Data Exchange (ETDEWEB)

    Beuville, E.; Beche, J.-F.; Cork, C. [and others

    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.

  7. ISPA (imaging silicon pixel array) experiment

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    Application components of ISPA tubes are shown: the CERN-developed anode chip, special windows for gamma and x-ray detection, scintillating crystal and fibre arrays for imaging and tracking of ionizing particles.

  8. ISPA (imaging silicon pixel array) experiment

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    The ISPA tube is a position-sensitive photon detector. It belongs to the family of hybrid photon detectors (HPD), recently developed by CERN and INFN with leading photodetector firms. HPDs confront in a vacuum envelope a photocathode and a silicon detector. This can be a single diode or a pixelized detector. The electrons generated by the photocathode are efficiently detected by the silicon anode by applying a high-voltage difference between them. ISPA tube can be used in high-energy applications as well as bio-medical and imaging applications.

  9. ISPA (imaging silicon pixel array) experiment

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    On the table, under the scrutiny of some collaboration members, an ISPA tube (upper-left of the table) with some of its application components is shown: they consist of the CERN-developed anode chip, special windows for gamma and x-ray detection, scintillating crystal and fibre arrays for imaging and tracking of ionizing particles.

  10. Smart pixel imaging with computational-imaging arrays

    Science.gov (United States)

    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.

  11. Experimental characterization and system simulations of depth of interaction PET detectors using 0.5 mm and 0.7 mm LSO arrays

    Science.gov (United States)

    James, Sara St; Yang, Yongfeng; Wu, Yibao; Farrell, Richard; Dokhale, Purushottam; Shah, Kanai S.; Cherry, Simon R.

    2009-07-01

    Small animal PET scanners may be improved by increasing the sensitivity, improving the spatial resolution and improving the uniformity of the spatial resolution across the field of view. This may be achieved by using PET detectors based on crystal elements that are thin in the axial and transaxial directions and long in the radial direction, and by employing depth of interaction (DOI) encoding to minimize the parallax error. With DOI detectors, the diameter of the ring of the PET scanner may also be decreased. This minimizes the number of detectors required to achieve the same solid angle coverage as a scanner with a larger ring diameter and minimizes errors due to non-collinearity of the annihilation photons. In this study, we characterize prototype PET detectors that are finely pixelated with individual LSO crystal element sizes of 0.5 mm × 0.5 mm × 20 mm and 0.7 mm × 0.7 mm × 20 mm, read out at both ends by position sensitive avalanche photodiodes (PSAPDs). Both a specular reflector and a diffuse reflector were evaluated. The detectors were characterized based on the ability to clearly resolve the individual crystal elements, the DOI resolution and the energy resolution. Our results indicate that a scanner based on any of the four detector designs would offer improved spatial resolution and more uniform spatial resolution compared to present day small animal PET scanners. The greatest improvements to spatial resolution will be achieved when the detectors employing the 0.5 mm × 0.5 mm × 20 mm crystals are used. Monte Carlo simulations were performed to demonstrate that 2 mm DOI resolution is adequate to ensure uniform spatial resolution for a small animal PET scanner geometry using these detectors. The sensitivity of such a scanner was also simulated using Monte Carlo simulations and was shown to be greater than 10% for a four ring scanner with an inner diameter of 6 cm, employing 20 detectors per scanner ring.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Jing Li

    2013-08-01

    Full Text Available 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.

  14. Digital pixel sensor array with logarithmic delta-sigma architecture.

    Science.gov (United States)

    Mahmoodi, Alireza; Li, Jing; Joseph, Dileepan

    2013-08-16

    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.

  15. Evaluation of a SiPM array detector coupled to a LFS-3 pixellated scintillator for PET/MR applications

    Energy Technology Data Exchange (ETDEWEB)

    David, Stratos; Fysikopoulos, Eleftherios [Technological Educational Institute of Athens (Greece); Georgiou, Maria [Technological Educational Institute of Athens (Greece); Department of Medical School, University of Thessaly, Larissa (Greece); Loudos, George [Technological Educational Institute of Athens (Greece)

    2015-05-18

    SiPM arrays are insensitive to magnetic fields and thus good candidates for hybrid PET/MR imaging systems. Moreover, due to their small size and flexibility can be used in dedicated small field of view small animal imaging detectors and especially in head PET/MR studies in mice. Co-doped LFS-3 scintillator crystals have higher light yield and slightly faster response than that of LSO:Ce mainly due to the co-doped activation of emission centers with varying materials such as Ce, Gd, Sc, Y, La, Tb, or Ca distributed at the molecular scale through the lutetium silicate crystal host. The purpose of this study is to investigate the behavior of the SensL ArraySL-4 (4x4 element array of 3x3 mm{sup 2} silicon photomultipliers) optical detector coupled to a 6x6 LFS-3 scintillator array, with 2x2x5 mm{sup 3} crystal size elements, for possible applications in small field of view PET/MR imaging detectors. We have designed a symmetric resistive charge division circuit to read out the signal outputs of 4x4 pixel SiPM array reducing the 16 pixel outputs of the photodetector to 4 position signals. The 4 position signals were digitized using free running Analog to Digital Converters. The ADCs sampling rate was 50 MHz. An FPGA (Spartan 6 LX150T) was used for triggering and digital signal processing of the pulses. Experimental evaluation was carried out with {sup 22}Na radioactive source and the parameters studied where energy resolution and peak to valley ratio. The first preliminary results of the evaluation shows a clear visualization of the discrete 2x2x5 mm{sup 3} LFS-3 scintillator elements. The mean peak to valley ratio of the horizontal profiles on the raw image was measured equal to 11 while the energy resolution was calculated equal to 30% at the central pixels.

  16. A 128 pixel linear array for radiotherapy quality assurance

    Science.gov (United States)

    Franco, L.; Gómez, F.; Iglesias, A.; Lobato, R.; Marín, J.; Mosquera, J.; Pardo, J.; Pazos, A.; Pena, J.; Pombar, M.; Rodríguez, A.; Saavedra, D.; Sendón, J.; Yañez, A.

    2004-12-01

    New radiotherapy techniques require detectors able to verify and monitor the clinical beam with high spatial resolution and fast response. Room temperature organic liquid ionization detectors are becoming an alternative to standard air ionization chambers, due to their tissue equivalent behavior, their sensibility and small directional dependence. A liquid isooctane filled ionization linear array for radiotherapy quality assurance has been designed, built and tested. The detector consists of 128 pixels, each of them with an area of 1.7 mm×1.7 mm and a gap of 0.5 mm. The small pixel size makes the detector ideal for high gradient beam profiles like those present in Intensity Modulated Radiation Therapy. The gap and the polarization voltage have been chosen in order to guarantee a linear relationship between the dose rate and the readout signal at high dose rates. As readout electronics we use the X-ray Data Acquisition System with the Xchip developed by the CCLRC.In the first device tests we have confirmed linearity up to a 6.7 Gy/min dose rate with a deviation less than 1%. A profile with a signal-to-noise ratio around 500 can be obtained for a 4 Gy/min dose rate with a 10 ms integration time.

  17. A 128 pixel linear array for radiotherapy quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Franco, L. [Departmento de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, campus sur s/n, 15782 Santiago de Compostela (Spain); Gomez, F. [Departmento de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, campus sur s/n, 15782 Santiago de Compostela (Spain)]. E-mail: faustgr@usc.es; Iglesias, A. [Departmento de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, campus sur s/n, 15782 Santiago de Compostela (Spain); Lobato, R. [Hospital Clinico Universitario de Santiago, 15706 Santiago (Spain); Marin, J. [CIEMAT, Laboratorio de Electronica y Automatica, 28040 Madrid Spain (Spain); Mosquera, J. [Hospital Clinico Universitario de Santiago, 15706 Santiago (Spain); Pardo, J. [Departmento de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, campus sur s/n, 15782 Santiago de Compostela (Spain)]. E-mail: juanpm@usc.es; Pazos, A. [Departmento de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, campus sur s/n, 15782 Santiago de Compostela (Spain); Pena, J. [Departmento de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, campus sur s/n, 15782 Santiago de Compostela (Spain); Pombar, M. [Hospital Clinico Universitario de Santiago, 15706 Santiago (Spain); Rodriguez, A. [Departmento de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, campus sur s/n, 15782 Santiago de Compostela (Spain); Saavedra, D. [Universidade da Coruna, Dpto. de Enxeneria Industrial II, 15403 Ferrol Spain (Spain); Sendon, J. [Hospital Clinico Universitario de Santiago, 15706 Santiago (Spain); Yanez, A. [Universidade da Coruna, Dpto. de Enxeneria Industrial II, 15403 Ferrol Spain (Spain)

    2004-12-11

    New radiotherapy techniques require detectors able to verify and monitor the clinical beam with high spatial resolution and fast response. Room temperature organic liquid ionization detectors are becoming an alternative to standard air ionization chambers, due to their tissue equivalent behavior, their sensibility and small directional dependence. A liquid isooctane filled ionization linear array for radiotherapy quality assurance has been designed, built and tested. The detector consists of 128 pixels, each of them with an area of 1.7mmx1.7mm and a gap of 0.5mm. The small pixel size makes the detector ideal for high gradient beam profiles like those present in Intensity Modulated Radiation Therapy. The gap and the polarization voltage have been chosen in order to guarantee a linear relationship between the dose rate and the readout signal at high dose rates. As readout electronics we use the X-ray Data Acquisition System with the Xchip developed by the CCLRC.In the first device tests we have confirmed linearity up to a 6.7Gy/min dose rate with a deviation less than 1%. A profile with a signal-to-noise ratio around 500 can be obtained for a 4Gy/min dose rate with a 10 ms integration time.

  18. Nano-fabricated pixelated micropolarizer array for visible imaging polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhigang; Cheng, Teng; Qiu, Kang; Zhang, Qingchuan, E-mail: zhangqc@ustc.edu.cn, E-mail: wgchu@nanoctr.cn; Wu, Xiaoping [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027 (China); Dong, Fengliang; Chu, Weiguo, E-mail: zhangqc@ustc.edu.cn, E-mail: wgchu@nanoctr.cn [Nanofabrication Laboratory, National Center for Nanoscience and Technology, Beijing 100190 (China)

    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.

  19. Nano-fabricated pixelated micropolarizer array for visible imaging polarimetry.

    Science.gov (United States)

    Zhang, Zhigang; Dong, Fengliang; Cheng, Teng; Qiu, Kang; Zhang, Qingchuan; Chu, Weiguo; Wu, Xiaoping

    2014-10-01

    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.

  20. Development of Kilo-Pixel Arrays of Transition-Edge Sensors for X-Ray Spectroscopy

    Science.gov (United States)

    Adams, J. S.; Bandler, S. R.; Busch, S. E.; Chervenak, J. A.; Chiao, M. P.; Eckart, M. E.; Ewin, A. J.; Finkbeiner, F. M.; Kelley, R. L.; Kelly, D. P.; Kilbourne, C. A.; Leutenegger, M. A.; Porst, J.-P.; Porter, F. S.; Ray, C. A.; Sadleir, J. E.; Smith, S. J.; Wassell, E. J.; Doriese, W. B.; Fowler, J. W.; Hilton, G. C.; Irwin, K. D.; Reintsema, C. D.; Smith, D. R.; Swetz, D. S.

    2012-01-01

    We are developing kilo-pixel arrays of transition-edge sensor (TES) microcalorimeters for future X-ray astronomy observatories or for use in laboratory astrophysics applications. For example, Athena/XMS (currently under study by the european space agency) would require a close-packed 32x32 pixel array on a 250-micron pitch with pixel/second. We present characterization of 32x32 arrays. These detectors will be readout using state of the art SQUID based time-domain multiplexing (TDM). We will also present the latest results in integrating these detectors and the TDM readout technology into a 16 row x N column field-able instrument.

  1. Photonic Heterodyne Pixel for Imaging Arrays at Microwave and MM-Wave Frequencies

    Directory of Open Access Journals (Sweden)

    Á. R. Criado

    2012-01-01

    Full Text Available The use of photonic heterodyne receivers based on semiconductor optical amplifiers to be used in imaging arrays at several GHz frequencies is evaluated. With this objective, a imaging array based on such photonic pixels has been fabricated and characterized. Each of the receiving optoelectronic pixels is composed of an antipodal linear tapered slot antenna (LTSA that sends the received RF signal directly to the electrical port of a semiconductor opticalamplifier (SOA acting as the optoelectronic mixer. Both the local oscillator (LO and the intermediate frequency (IF signals are directly distributed to/from the array pixels using fiber optics, that allows for remote LO generation and IF processing to recover the image. The results shown in this work demonstrate that the performances of the optoelectronic imaging array are similar to a reference all-electronic array, revealing the possibility of using this photonic architecture in future high-density, scalable, compact imaging arrays in microwave and millimeter wave ranges.

  2. Study of the characteristics of a scintillation array and single pixels for nuclear medicine imaging applications

    Institute of Scientific and Technical Information of China (English)

    ZHU Jie; MA Hong-Guang; MA Wen-Yan; ZENG Hui; WANG Zhao-Min; XU Zi-Zong

    2009-01-01

    By using a pixelized Nal(T1) crystal array coupled to a R2486 PSPMT, the characteristics of the array and of a single pixel, such as the light output, energy resolution, peak-to-valley ratio (P/V) and imaging performance of the detector were studied. The pixel size of the NaI(TI) scintillation pixel array is 2 min×2 mm×5 mm. There are in total 484 pixels in a 22~22 matrix. In the pixel spectrum an average peak-to-valley ratio (P/V) of 16 was obtained. In the image of all the pixels, good values for the Peak-to-Valley ratios could be achieved, namely a mean of 17, a maximum of 45 and the average peak FWHM (the average value of intrinsic spatial resolution) of 2.3 mm. However, the PSPMT non-uniform response and the scintillation pixels array inhomogeneities degrade the imaging performance of the detector.

  3. CMOS-compatible PureGaB Ge-on-Si APD pixel arrays

    NARCIS (Netherlands)

    Sammak, Amir; Aminian, Mahdi; Nanver, Lis Karen; Charbon, Edoardo

    2016-01-01

    Pure gallium and pure boron (PureGaB) Ge-on-Si photodiodes were fabricated in a CMOS compatible process and operated in linear and avalanche mode. Three different pixel geometries with very different area-to-perimeter ratios were investigated in linear arrays of 300 pixels with each a size of 26 × 2

  4. Characterization of novel Hamamatsu Multi Pixel Photon Counter (MPPC) arrays for the GlueX experiment

    Energy Technology Data Exchange (ETDEWEB)

    Soto, Orlando [Universidad T?cnica Federico Santa Mar?a; Rojas, Rimsky [Universidad T?cnica Federico Santa Mar?a; Kuleshov, Sergey V. [Universidad T?cnica Federico Santa Mar?a; Hakobyan, Hayk [Universidad T?cnica Federico Santa Mar?a; Toro, Alam [Universidad T?cnica Federico Santa Mar?a; Brooks, William K. [Universidad T?cnica Federico Santa Mar?a

    2013-12-01

    The novel Hamamatsu Multi Pixel Photon Counter Array S12045(X) is an array of 16 individual MPPCs (3x3 mm{sup 2}) (further in the paper MPPC array channel) each with 3600 G-APD (Geiger-mode Avalanche Photodiodes) pixels (50x50 [{micro}m{sup 2}]). Each MPPC in the array works with its individual reverse bias voltage mode (around 70 V). The paper summarizes the characterization process of MPPC arrays used in GlueX experiment (Hall D, Jefferson Lab). We studied the main features of each MPPC array channel for 2800 MPPC arrays at different temperatures. Two measurement stations were built to extract gain, breakdown voltage, photo detection efficiency (PDE), optical crosstalk and dark rate for each MPPC array channel. The hardware and the data analysis are described, which includes new analytical expressions to obtain the mean number of photo-electrons and optical crosstalk. The dynamical behavior of characterization parameters is presented as well.

  5. Characterization of novel Hamamatsu Multi Pixel Photon Counter (MPPC) arrays for the GlueX experiment

    Science.gov (United States)

    Soto, Orlando; Rojas, Rimsky; Kuleshov, Sergey; Hakobyan, Hayk; Toro, Alam; Brooks, William K.

    2013-12-01

    The novel Hamamatsu Multi Pixel Photon Counter Array S12045(X) is an array of 16 individual MPPCs (3×3 mm2) (further in the paper MPPC array channel) each with 3600 G-APD (Geiger-mode Avalanche Photodiodes) pixels (50×50 [μm2]). Each MPPC in the array works with its individual reverse bias voltage mode (around 70 V). The paper summarizes the characterization process of MPPC arrays used in GlueX experiment (Hall D, Jefferson Lab). We studied the main features of each MPPC array channel for 2800 MPPC arrays at different temperatures. Two measurement stations were built to extract gain, breakdown voltage, photo detection efficiency (PDE), optical crosstalk and dark rate for each MPPC array channel. The hardware and the data analysis are described, which includes new analytical expressions to obtain the mean number of photo-electrons and optical crosstalk. The dynamical behavior of characterization parameters is presented as well.

  6. Characterization of novel Hamamatsu Multi Pixel Photon Counter (MPPC) arrays for the GlueX experiment

    Energy Technology Data Exchange (ETDEWEB)

    Soto, Orlando, E-mail: oj.5070@gmail.com; Rojas, Rimsky; Kuleshov, Sergey; Hakobyan, Hayk; Toro, Alam; Brooks, William K.

    2013-12-21

    The novel Hamamatsu Multi Pixel Photon Counter Array S12045(X) is an array of 16 individual MPPCs (3×3 mm{sup 2}) (further in the paper MPPC array channel) each with 3600 G-APD (Geiger-mode Avalanche Photodiodes) pixels (50×50 [μm{sup 2}]). Each MPPC in the array works with its individual reverse bias voltage mode (around 70 V). The paper summarizes the characterization process of MPPC arrays used in GlueX experiment (Hall D, Jefferson Lab). We studied the main features of each MPPC array channel for 2800 MPPC arrays at different temperatures. Two measurement stations were built to extract gain, breakdown voltage, photo detection efficiency (PDE), optical crosstalk and dark rate for each MPPC array channel. The hardware and the data analysis are described, which includes new analytical expressions to obtain the mean number of photo-electrons and optical crosstalk. The dynamical behavior of characterization parameters is presented as well.

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

    Science.gov (United States)

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

    2007-04-01

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

  8. Alternative Optimizations of X-ray TES Arrays: Soft X-rays, High Count Rates, and Mixed-Pixel Arrays

    Science.gov (United States)

    Kilbourne, C. A.; Bandler, S. R.; Brown, A.-D.; Chervenak, J. A.; Figueroa-Feliciano, E.; Finkbeiner, F. M.; Iyomoto, N.; Kelley, R. L.; Porter, F. S.; Smith, S. J.

    2007-01-01

    We are developing arrays of superconducting transition-edge sensors (TES) for imaging spectroscopy telescopes such as the XMS on Constellation-X. While our primary focus has been on arrays that meet the XMS requirements (of which, foremost, is an energy resolution of 2.5 eV at 6 keV and a bandpass from approx. 0.3 keV to 12 keV), we have also investigated other optimizations that might be used to extend the XMS capabilities. In one of these optimizations, improved resolution below 1 keV is achieved by reducing the heat capacity. Such pixels can be based on our XMS-style TES's with the separate absorbers omitted. These pixels can added to an array with broadband response either as a separate array or interspersed, depending on other factors that include telescope design and science requirements. In one version of this approach, we have designed and fabricated a composite array of low-energy and broad-band pixels to provide high spectral resolving power over a broader energy bandpass than could be obtained with a single TES design. The array consists of alternating pixels with and without overhanging absorbers. To explore optimizations for higher count rates, we are also optimizing the design and operating temperature of pixels that are coupled to a solid substrate. We will present the performance of these variations and discuss other optimizations that could be used to enhance the XMS or enable other astrophysics experiments.

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

    CERN Document Server

    Zumbiehl, A; Fougeres, P; Koebel, J M; Regal, R; Rit, C; Ayoub, M; Siffert, P

    2001-01-01

    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: af...

  10. Pixel parallel localized driver design for a 128 x 256 pixel array 3D 1Gfps image sensor

    Science.gov (United States)

    Zhang, C.; Dao, V. T. S.; Etoh, T. G.; Charbon, E.

    2017-02-01

    In this paper, a 3D 1Gfps BSI image sensor is proposed, where 128 × 256 pixels are located in the top-tier chip and a 32 × 32 localized driver array in the bottom-tier chip. Pixels are designed with Multiple Collection Gates (MCG), which collects photons selectively with different collection gates being active at intervals of 1ns to achieve 1Gfps. For the drivers, a global PLL is designed, which consists of a ring oscillator with 6-stage current starved differential inverters, achieving a wide frequency tuning range from 40MHz to 360MHz (20ps rms jitter). The drivers are the replicas of the ring oscillator that operates within a PLL. Together with level shifters and XNOR gates, continuous 3.3V pulses are generated with desired pulse width, which is 1/12 of the PLL clock period. The driver array is activated by a START signal, which propagates through a highly balanced clock tree, to activate all the pixels at the same time with virtually negligible skew.

  11. A near-infrared 64-pixel superconducting nanowire single photon detector array with integrated multiplexed readout

    Energy Technology Data Exchange (ETDEWEB)

    Allman, M. S., E-mail: shane.allman@boulder.nist.gov; Verma, V. B.; Stevens, M.; Gerrits, T.; Horansky, R. D.; Lita, A. E.; Mirin, R.; Nam, S. W. [National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305-3328 (United States); Marsili, F.; Beyer, A.; Shaw, M. D. [Jet Propulsion Laboratory, 4800 Oak Grove Dr., Pasadena, California 91109 (United States); Kumor, D. [Purdue University, 610 Purdue Mall, West Lafayette, Indiana 47907 (United States)

    2015-05-11

    We demonstrate a 64-pixel free-space-coupled array of superconducting nanowire single photon detectors optimized for high detection efficiency in the near-infrared range. An integrated, readily scalable, multiplexed readout scheme is employed to reduce the number of readout lines to 16. The cryogenic, optical, and electronic packaging to read out the array as well as characterization measurements are discussed.

  12. A Near-Infrared 64-pixel Superconducting Nanowire Single Photon Detector Array with Integrated Multiplexed Readout

    CERN Document Server

    Allman, M S; Stevens, M; Gerrits, T; Horansky, R D; Lita, A E; Marsili, F; Beyer, A; Shaw, M D; Kumor, D; Mirin, R; Nam, S W

    2015-01-01

    We demonstrate a 64-pixel free-space-coupled array of superconducting nanowire single photon detectors optimized for high detection efficiency in the near-infrared range. An integrated, readily scalable, multiplexed readout scheme is employed to reduce the number of readout lines to 16. The cryogenic, optical, and electronic packaging to read out the array, as well as characterization measurements are discussed.

  13. A 400 KHz line rate 2048-pixel stitched SWIR linear array

    Science.gov (United States)

    Anchlia, Ankur; Vinella, Rosa M.; Gielen, Daphne; Wouters, Kristof; Vervenne, Vincent; Hooylaerts, Peter; Deroo, Pieter; Ruythooren, Wouter; De Gaspari, Danny; Das, Jo; Merken, Patrick

    2016-05-01

    Xenics has developed a family of stitched SWIR long linear arrays that operate up to 400 KHz of line rate. These arrays serve medical and industrial applications that require high line rates as well as space applications that require long linear arrays. 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. Each 512-pixel module has its own on-chip digital sequencer, analog readout chain and 4 output buffers. This modular concept enables a long array to run at a high line rates irrespective of the array length, which limits the line rate in a traditional linear array. The ROIC is flip-chipped with InGaAs detector arrays. The FPA has a pixel pitch of 12.5μm and has two pixel flavors: square (12.5μm) and rectangular (250μm). The frontend circuit is based on Capacitive Trans-impedance Amplifier (CTIA) to attain stable detector bias, and good linearity and signal integrity, especially at high speeds. The CTIA has an input auto-zero mechanism that allows to have low detector bias (<20mV). An on-chip Correlated Double Sample (CDS) facilitates removal of CTIA KTC and 1/f noise, and other offsets, achieving low noise performance. There are five gain modes in the FPA giving the full well range from 85Ke- to 40Me-. The measured input referred noise is 35e-rms in the highest gain mode. The FPA operates in Integrate While Read mode and, at a master clock rate of 60MHz and a minimum integration time of 1.4μs, achieves the highest line rate of 400 KHz. In this paper, design details and measurements results are presented in order to demonstrate the array performance.

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

    Science.gov (United States)

    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.

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

    CERN Document Server

    Tate, Mark W; Chamberlain, Darol; Nguyen, Kayla X; Hovden, Robert M; 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

    2015-01-01

    We describe a hybrid pixel array detector (EMPAD - electron microscope pixel array detector) adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy. The 128 x 128 pixel detector consists of a 500 um thick silicon diode array bump-bonded pixel-by-pixel to an application-specific integrated circuit (ASIC). 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 loc...

  16. Design, optimization and evaluation of a "smart" pixel sensor array for low-dose digital radiography

    Science.gov (United States)

    Wang, Kai; Liu, Xinghui; Ou, Hai; Chen, Jun

    2016-04-01

    Amorphous silicon (a-Si:H) thin-film transistors (TFTs) have been widely used to build flat-panel X-ray detectors for digital radiography (DR). As the demand for low-dose X-ray imaging grows, a detector with high signal-to-noise-ratio (SNR) pixel architecture emerges. "Smart" pixel is intended to use a dual-gate photosensitive TFT for sensing, storage, and switch. It differs from a conventional passive pixel sensor (PPS) and active pixel sensor (APS) in that all these three functions are combined into one device instead of three separate units in a pixel. Thus, it is expected to have high fill factor and high spatial resolution. In addition, it utilizes the amplification effect of the dual-gate photosensitive TFT to form a one-transistor APS that leads to a potentially high SNR. This paper addresses the design, optimization and evaluation of the smart pixel sensor and array for low-dose DR. We will design and optimize the smart pixel from the scintillator to TFT levels and validate it through optical and electrical simulation and experiments of a 4x4 sensor array.

  17. Readout of a 176 pixel FDM system for SAFARI TES arrays

    Science.gov (United States)

    Hijmering, R. A.; den Hartog, R.; Ridder, M.; van der Linden, A. J.; van der Kuur, J.; Gao, J. R.; Jackson, B.

    2016-07-01

    In this paper we present the results of our 176-pixel prototype of the FDM readout system for SAFARI, a TES-based focal-plane instrument for the far-IR SPICA mission. We have implemented the knowledge obtained from the detailed study on electrical crosstalk reported previously. The effect of carrier leakage is reduced by a factor two, mutual impedance is reduced to below 1 nH and mutual inductance is removed. The pixels are connected in stages, one quarter of the array half of the array and the full array, to resolve intermediate technical issues. A semi-automated procedure was incorporated to find all optimal settings for all pixels. And as a final step the complete array has been connected and 132 pixels have been read out simultaneously within the frequency range of 1-3.8MHz with an average frequency separation of 16kHz. The noise was found to be detector limited and was not affected by reading out all pixels in a FDM mode. With this result the concept of using FDM for multiplexed bolometer read out for the SAFARI instrument has been demonstrated.

  18. X-ray Characterization of a Multichannel Smart-Pixel Array Detector

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Steve; Haji-Sheikh, Michael; Huntington, Andrew; Kline, David; Lee, Adam; Li, Yuelin; Rhee, Jehyuk; Tarpley, Mary; Walko, Donald A.; Westberg, Gregg; Williams, George; Zou, Haifeng; Landahl, Eric

    2016-01-01

    The Voxtel VX-798 is a prototype X-ray pixel array detector (PAD) featuring a silicon sensor photodiode array of 48 x 48 pixels, each 130 mu m x 130 mu m x 520 mu m thick, coupled to a CMOS readout application specific integrated circuit (ASIC). The first synchrotron X-ray characterization of this detector is presented, and its ability to selectively count individual X-rays within two independent arrival time windows, a programmable energy range, and localized to a single pixel is demonstrated. During our first trial run at Argonne National Laboratory's Advance Photon Source, the detector achieved a 60 ns gating time and 700 eV full width at half-maximum energy resolution in agreement with design parameters. Each pixel of the PAD holds two independent digital counters, and the discriminator for X-ray energy features both an upper and lower threshold to window the energy of interest discarding unwanted background. This smart-pixel technology allows energy and time resolution to be set and optimized in software. It is found that the detector linearity follows an isolated dead-time model, implying that megahertz count rates should be possible in each pixel. Measurement of the line and point spread functions showed negligible spatial blurring. When combined with the timing structure of the synchrotron storage ring, it is demonstrated that the area detector can perform both picosecond time-resolved X-ray diffraction and fluorescence spectroscopy measurements.

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

    Energy Technology Data Exchange (ETDEWEB)

    Philipp, Hugh T., E-mail: htp2@cornell.edu; Tate, Mark W.; Purohit, Prafull; Shanks, Katherine S.; Weiss, Joel T. [Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M. [Cornell University, Ithaca, NY 14853 (United States); Cornell University, Ithaca, NY 14853 (United States)

    2016-01-28

    A high-speed pixel array detector for time-resolved X-ray imaging at synchrotrons has been developed. The ability to isolate single synchrotron bunches makes it ideal for time-resolved dynamical studies. 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.

  20. The high dynamic range pixel array detector (HDR-PAD): Concept and design

    Energy Technology Data Exchange (ETDEWEB)

    Shanks, Katherine S.; Philipp, Hugh T.; Weiss, Joel T.; Becker, Julian; Tate, Mark W. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M., E-mail: smg26@cornell.edu [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States)

    2016-07-27

    Experiments at storage ring light sources as well as at next-generation light sources increasingly require detectors capable of high dynamic range operation, combining low-noise detection of single photons with large pixel well depth. XFEL sources in particular provide pulse intensities sufficiently high that a purely photon-counting approach is impractical. The High Dynamic Range Pixel Array Detector (HDR-PAD) project aims to provide a dynamic range extending from single-photon sensitivity to 10{sup 6} photons/pixel in a single XFEL pulse while maintaining the ability to tolerate a sustained flux of 10{sup 11} ph/s/pixel at a storage ring source. Achieving these goals involves the development of fast pixel front-end electronics as well as, in the XFEL case, leveraging the delayed charge collection due to plasma effects in the sensor. A first prototype of essential electronic components of the HDR-PAD readout ASIC, exploring different options for the pixel front-end, has been fabricated. Here, the HDR-PAD concept and preliminary design will be described.

  1. Study of performance of small gamma camera consisting of crystal pixel array and position sensitive photomultiplier tube

    Institute of Scientific and Technical Information of China (English)

    ZHU Jie; LIU Shi-Tao; LEI Xiao-Wen; YAN Tian-Xin; XU Zi-Zong; WANG Zhao-Min

    2005-01-01

    The performance of gamma camera with NaI(T1) array coupled with position sensitive photomultiplier tube (PSPMT) R2486 has been studied. The pixel size of NaI(T1) crystal is 2mm×2mm and the overall dimension of the array is 48.2mm×48.2mm×5mm. There are 484 pixels in a 22×22 matrix. Because each pixel can produce a much focused light spot and restrict the spread of photons, position resolution of the gamma camera is mainly determined by pixel size. It is shown that crystal array pixel can reduce shrinkage effect and improve intrinsic position resolution greatly via restricting the spread of photons. Experimental results demonstrate that its position resolution and linearity are much improved comparing with the gamma camera using planar crystals coupled with PSPMT.

  2. Versatile, reprogrammable area pixel array detector for time-resolved synchrotron x-ray applications

    Energy Technology Data Exchange (ETDEWEB)

    Gruner, Sol [Cornell Univ., Ithaca, NY (United States)

    2010-05-01

    The final technical report for DOE grant DE-SC0004079 is presented. The goal of the grant was to perform research, development and application of novel imaging x-ray detectors so as to effectively utilize the high intensity and brightness of the national synchrotron radiation facilities to enable previously unfeasible time-resolved x-ray research. The report summarizes the development of the resultant imaging x-ray detectors. Two types of detector platforms were developed: The first is a detector platform (called a Mixed-Mode Pixel Array Detector, or MM-PAD) that can image continuously at over a thousand images per second while maintaining high efficiency for wide dynamic range signals ranging from 1 to hundreds of millions of x-rays per pixel per image. Research on an even higher dynamic range variant is also described. The second detector platform (called the Keck Pixel Array Detector) is capable of acquiring a burst of x-ray images at a rate of millions of images per second.

  3. Parallel pipeline networking and signal processing with field-programmable gate arrays (FPGAs) and VCSEL-MSM smart pixels

    Science.gov (United States)

    Kuznia, C. B.; Sawchuk, Alexander A.; Zhang, Liping; Hoanca, Bogdan; Hong, Sunkwang; Min, Chris; Pansatiankul, Dhawat E.; Alpaslan, Zahir Y.

    2000-05-01

    We present a networking and signal processing architecture called Transpar-TR (Translucent Smart Pixel Array-Token- Ring) that utilizes smart pixel technology to perform 2D parallel optical data transfer between digital processing nodes. Transpar-TR moves data through the network in the form of 3D packets (2D spatial and 1D time). By utilizing many spatial parallel channels, Transpar-TR can achieve high throughput, low latency communication between nodes, even with each channel operating at moderate data rates. The 2D array of optical channels is created by an array of smart pixels, each with an optical input and optical output. Each smart pixel consists of two sections, an optical network interface and ALU-based processor with local memory. The optical network interface is responsible for transmitting and receiving optical data packets using a slotted token ring network protocol. The smart pixel array operates as a single-instruction multiple-data processor when processing data. The Transpar-TR network, consisting of networked smart pixel arrays, can perform pipelined parallel processing very efficiently on 2D data structures such as images and video. This paper discusses the Transpar-TR implementation in which each node is the printed circuit board integration of a VCSEL-MSM chip, a transimpedance receiver array chip and an FPGA chip.

  4. Multiplexed Readout for 1000-pixel Arrays of Microwave Kinetic Inductance Detectors

    CERN Document Server

    van Rantwijk, Joris; van Loon, Dennis; Yates, Stephen; Baryshev, Andrey; Baselmans, Jochem

    2015-01-01

    Microwave Kinetic Inductance Detectors (MKIDs) are the most attractive radiation detectors for far-infrared and sub-mm astronomy: They combine ultimate sensitivity with the possibility to create very large detector arrays, in excess of 10 000 pixels. This is possible by reading-out the arrays using RF frequency division multiplexing, which allows multiplexing ratios in excess of 1000 pixels per readout line. We describe a novel readout system for large arrays of MKIDs, operating in a 2 GHz band in the 4-8 GHz range. The readout, which is a combination of a digital front- and back-end and an analog up- and down-converter system, can read out up to 4000 detectors simultaneously with 1 kHz datarate. The system achieves a readout noise power spectral density of -98 dBc/Hz while reading 1000 carriers simultaneously, which scales linear with the number of carriers. We demonstrate that 4000 state-of-the-art Aluminium-NbTiN MKIDs can be read out without deteriorating their intrinsic performance.

  5. 64-pixel NbTiN superconducting nanowire single-photon detector array for spatially resolved photon detection

    CERN Document Server

    Miki, Shigehito; Wang, Zhen; Terai, Hirotaka

    2014-01-01

    We present the characterization of two-dimensionally arranged 64-pixel NbTiN superconducting nanowire single-photon detector array for spatially resolved photon detection. NbTiN films deposited on thermally oxidized Si substrates enabled the high-yield production of high-quality SSPD pixels, and all 64 SSPD pixels showed uniform superconducting characteristics. Furthermore, all of the pixels showed single-photon sensitivity, and 60 of the 64 pixels showed a pulse generation probability higher than 90% after photon absorption. As a result of light irradiation from the single-mode optical fiber at different distances between the fiber tip and the active area, the variations of system detection efficiency in each pixel showed reasonable Gaussian distribution to represent the spatial distributions of photon flux intensity.

  6. Integrated X-ray and charged particle active pixel CMOS sensor arrays using an epitaxial silicon sensitive region

    Energy Technology Data Exchange (ETDEWEB)

    Kleinfelder, Stuart; Bichsel, Hans; Bieser, Fred; Matis, Howard S.; Rai, Gulshan; Retiere, Fabrice; Weiman, Howard; Yamamoto, Eugene

    2002-07-01

    Integrated CMOS Active Pixel Sensor (APS) arrays have been fabricated and tested using X-ray and electron sources. The 128 by 128 pixel arrays, designed in a standard 0.25 micron process, use a {approx}10 micron epitaxial silicon layer as a deep detection region. The epitaxial layer has a much greater thickness than the surface features used by standard CMOS APS, leading to stronger signals and potentially better signal-to-noise ratio (SNR). On the other hand, minority carriers confined within the epitaxial region may diffuse to neighboring pixels, blur images and reduce peak signal intensity. But for low-rate, sparse-event images, centroid analysis of this diffusion may be used to increase position resolution. Careful trade-offs involving pixel size and sense-node area verses capacitance must be made to optimize overall performance. The prototype sensor arrays, therefore, include a range of different pixel designs, including different APS circuits and a range of different epitaxial layer contact structures. The fabricated arrays were tested with 1.5 GeV electrons and Fe-55 X-ray sources, yielding a measured noise of 13 electrons RMS and an SNR for single Fe-55 X-rays of greater than 38.

  7. A single-pixel optical-sectioning programmable array microscope (SP-PAM)

    Science.gov (United States)

    Wu, Y.; Ye, P.; Arce, G. R.; Prather, D. W.

    2010-02-01

    Programmable array microscopes (PAMs) use "multi-pinhole" masks in confocal image planes to introduce illumination and block the "out-of-focus light". Compared to traditional confocal microscopes (CM), PAM systems have higher efficiency in utilizing the signal light and faster image acquisition speed. However, these advantages are gained at the cost of using more complicated optics and detectors. Compressive sampling (CS) measurement patterns can be used as pinhole masks in PAM systems. With CS patterns, the light collected after the detector mask can be summed up and used to reconstruct the imaging scene via solving an l1-minimization problem. Only a simple relay-lens and a singlepixel detector are needed to measure the intensity of the summed light. Therefore the optical complexity associated with conventional PAM systems can be reduced. Since only a single-pixel detector is needed, this system can also be called a single-pixel PAM or SP-PAM system. In this work, we introduce the design and fabrication of a prototype SP-PAM system. In this system, scrambled-block Hadamard ensembles (SBHE) are used as CS measurement patterns and a digital micromirror device (DMD) is employed to realize these patterns.

  8. Robustness of Planar Fourier Capture Arrays to Colour Changes and Lost Pixels

    CERN Document Server

    Gill, Patrick R; Sivaramakrishnan, Sriram; Molnar, Alyosha

    2011-01-01

    Planar Fourier capture arrays (PFCAs) are optical sensors built entirely in standard microchip manufacturing flows. PFCAs are composed of ensembles of angle sensitive pixels (ASPs) that each report a single coefficient of the Fourier transform of the far-away scene. Here we characterize the performance of PFCAs under the following three non-optimal conditions. First, we show that PFCAs can operate while sensing light of a wavelength other than the design point. Second, if only a randomly-selected subset of 10% of the ASPs are functional, we can nonetheless reconstruct the entire far-away scene using compressed sensing. Third, if the wavelength of the imaged light is unknown, it can be inferred by demanding self-consistency of the outputs.

  9. Development and operation of a pixel segmented liquid-filled linear array for radiotherapy quality assurance

    Science.gov (United States)

    Pardo, J.; Franco, L.; Gómez, F.; Iglesias, A.; Pazos, A.; Pena, J.; Lobato, R.; Mosquera, J.; Pombar, M.; Sendón, J.

    2005-04-01

    A liquid isooctane (C8H18) filled ionization linear array for radiotherapy quality assurance has been designed, built and tested. The detector consists of 128 pixels, each of them with an area of 1.7 mm × 1.7 mm and a gap of 0.5 mm. The small pixel size makes the detector ideal for high gradient beam profiles such as those present in intensity modulated radiation therapy (IMRT) and radiosurgery. As the read-out electronics we use the X-ray Data Acquisition System with the Xchip developed by the CCLRC. Studies concerning the collection efficiency dependence on the polarization voltage and on the dose rate have been made in order to optimize the device operation. In the first tests, we have studied dose rate and energy dependences. Dose rate dependence was found to be lower than 2.1% up to 5 Gy min-1, and energy dependence lower than 2.5% up to 20 cm depth in solid water. Output factors and penumbras for several rectangular fields have been measured with the linear array and were compared with the results obtained with a 0.125 cm3 air ionization chamber and radiographic film, respectively. Finally, we have acquired profiles for an IMRT field and for a virtual wedge. These profiles have also been compared with radiographic film measurements. All the comparisons show a good correspondence. The device has proved its capability to verify on-line therapy beams with good spatial resolution and signal-to-noise ratio.

  10. Development and operation of a pixel segmented liquid-filled linear array for radiotherapy quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, J [Departamento de Fisica de Particulas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Franco, L [Departamento de Fisica de Particulas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Gomez, F [Departamento de Fisica de Particulas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Iglesias, A [Departamento de Fisica de Particulas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Pazos, A [Departamento de Fisica de Particulas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Pena, J [Departamento de Fisica de Particulas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Lobato, R [Hospital Clinico Universitario de Santiago, Santiago (Spain); Mosquera, J [Hospital Clinico Universitario de Santiago, Santiago (Spain); Pombar, M [Hospital Clinico Universitario de Santiago, Santiago (Spain); Sendon, J [Hospital Clinico Universitario de Santiago, Santiago (Spain)

    2005-04-21

    A liquid isooctane (C{sub 8}H{sub 18}) filled ionization linear array for radiotherapy quality assurance has been designed, built and tested. The detector consists of 128 pixels, each of them with an area of 1.7 mm x 1.7 mm and a gap of 0.5 mm. The small pixel size makes the detector ideal for high gradient beam profiles such as those present in intensity modulated radiation therapy (IMRT) and radiosurgery. As the read-out electronics we use the X-ray Data Acquisition System with the Xchip developed by the CCLRC. Studies concerning the collection efficiency dependence on the polarization voltage and on the dose rate have been made in order to optimize the device operation. In the first tests, we have studied dose rate and energy dependences. Dose rate dependence was found to be lower than 2.1% up to 5 Gy min{sup -1}, and energy dependence lower than 2.5% up to 20 cm depth in solid water. Output factors and penumbras for several rectangular fields have been measured with the linear array and were compared with the results obtained with a 0.125 cm{sup 3} air ionization chamber and radiographic film, respectively. Finally, we have acquired profiles for an IMRT field and for a virtual wedge. These profiles have also been compared with radiographic film measurements. All the comparisons show a good correspondence. The device has proved its capability to verify on-line therapy beams with good spatial resolution and signal-to-noise ratio.

  11. Thermal quenching and electron traps in LSO

    Energy Technology Data Exchange (ETDEWEB)

    Kappers, L.A. E-mail: kappers@uconnvm.uconn.edu; Bartram, R.H.; Hamilton, D.S.; Lempicki, A.; Glodo, J

    2003-05-01

    It is demonstrated by comparison of thermoluminescence and scintillation light outputs of LSO as functions of radiation time that a previously suggested thermal quenching correction is inappropriate. Approximate solutions of rate equations are employed to infer absolute trap concentrations and to explore the effects of thermal quenching on the shapes of thermoluminescence glow curves.

  12. High-dynamic-range coherent diffractive imaging: ptychography using the mixed-mode pixel array detector

    Energy Technology Data Exchange (ETDEWEB)

    Giewekemeyer, Klaus, E-mail: klaus.giewekemeyer@xfel.eu [European XFEL GmbH, Hamburg (Germany); Philipp, Hugh T. [Cornell University, Ithaca, NY (United States); Wilke, Robin N. [Georg-August-Universität Göttingen, Göttingen (Germany); Aquila, Andrew [European XFEL GmbH, Hamburg (Germany); Osterhoff, Markus [Georg-August-Universität Göttingen, Göttingen (Germany); Tate, Mark W.; Shanks, Katherine S. [Cornell University, Ithaca, NY (United States); Zozulya, Alexey V. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Salditt, Tim [Georg-August-Universität Göttingen, Göttingen (Germany); Gruner, Sol M. [Cornell University, Ithaca, NY (United States); Cornell University, Ithaca, NY (United States); Kavli Institute of Cornell for Nanoscience, Ithaca, NY (United States); Mancuso, Adrian P. [European XFEL GmbH, Hamburg (Germany)

    2014-08-07

    The advantages of a novel wide dynamic range hard X-ray detector are demonstrated for (ptychographic) coherent X-ray diffractive imaging. Coherent (X-ray) diffractive imaging (CDI) is an increasingly popular form of X-ray microscopy, mainly due to its potential to produce high-resolution images and the lack of an objective lens between the sample and its corresponding imaging detector. One challenge, however, is that very high dynamic range diffraction data must be collected to produce both quantitative and high-resolution images. In this work, hard X-ray ptychographic coherent diffractive imaging has been performed at the P10 beamline of the PETRA III synchrotron to demonstrate the potential of a very wide dynamic range imaging X-ray detector (the Mixed-Mode Pixel Array Detector, or MM-PAD). The detector is capable of single photon detection, detecting fluxes exceeding 1 × 10{sup 8} 8-keV photons pixel{sup −1} s{sup −1}, and framing at 1 kHz. A ptychographic reconstruction was performed using a peak focal intensity on the order of 1 × 10{sup 10} photons µm{sup −2} s{sup −1} within an area of approximately 325 nm × 603 nm. This was done without need of a beam stop and with a very modest attenuation, while ‘still’ images of the empty beam far-field intensity were recorded without any attenuation. The treatment of the detector frames and CDI methodology for reconstruction of non-sensitive detector regions, partially also extending the active detector area, are described.

  13. Tiled Array of Pixelated CZT Imaging Detectors for ProtoEXIST2 and MIRAX-HXI

    CERN Document Server

    Hong, Jaesub; Grindlay, Jonathan; Rodrigues, Barbara; Ellis, Jon Robert; Baker, Robert; Barthelmy, Scott; Mao, Peter; Miyasaka, Hiromasa; Apple, Jeff

    2013-01-01

    We have assembled a tiled array (220 cm2) of fine pixel (0.6 mm) imaging CZT detectors for a balloon borne wide-field hard X-ray telescope, ProtoEXIST2. ProtoEXIST2 is a prototype experiment for a next generation hard X-ray imager MIRAX-HXI on board Lattes, a spacecraft from the Agencia Espacial Brasilieira. MIRAX will survey the 5 to 200 keV sky of Galactic bulge, adjoining southern Galactic plane and the extragalactic sky with 6' angular resolution. This survey will open a vast discovery space in timing studies of accretion neutron stars and black holes. The ProtoEXIST2 CZT detector plane consists of 64 of 5 mm thick 2 cm x 2 cm CZT crystals tiled with a minimal gap. MIRAX will consist of 4 such detector planes, each of which will be imaged with its own coded-aperture mask. We present the packaging architecture and assembly procedure of the ProtoEXIST2 detector. On 2012, Oct 10, we conducted a successful high altitude balloon experiment of the ProtoEXIST1 and 2 telescopes, which demonstrates their technolog...

  14. High-dynamic-range coherent diffractive imaging: ptychography using the mixed-mode pixel array detector

    Science.gov (United States)

    Giewekemeyer, Klaus; Philipp, Hugh T.; Wilke, Robin N.; Aquila, Andrew; Osterhoff, Markus; Tate, Mark W.; Shanks, Katherine S.; Zozulya, Alexey V.; Salditt, Tim; Gruner, Sol M.; Mancuso, Adrian P.

    2014-01-01

    Coherent (X-ray) diffractive imaging (CDI) is an increasingly popular form of X-ray microscopy, mainly due to its potential to produce high-resolution images and the lack of an objective lens between the sample and its corresponding imaging detector. One challenge, however, is that very high dynamic range diffraction data must be collected to produce both quantitative and high-resolution images. In this work, hard X-ray ptychographic coherent diffractive imaging has been performed at the P10 beamline of the PETRA III synchrotron to demonstrate the potential of a very wide dynamic range imaging X-ray detector (the Mixed-Mode Pixel Array Detector, or MM-PAD). The detector is capable of single photon detection, detecting fluxes exceeding 1 × 108 8-keV photons pixel−1 s−1, and framing at 1 kHz. A ptychographic reconstruction was performed using a peak focal intensity on the order of 1 × 1010 photons µm−2 s−1 within an area of approximately 325 nm × 603 nm. This was done without need of a beam stop and with a very modest attenuation, while ‘still’ images of the empty beam far-field intensity were recorded without any attenuation. The treatment of the detector frames and CDI methodology for reconstruction of non-sensitive detector regions, partially also extending the active detector area, are described. PMID:25178008

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  16. Novel Hamamatsu Multi-Pixel Photon Counter (MPPC) array studies for the GlueX experiment: New results

    Science.gov (United States)

    Soto, Orlando; Rojas, Rimsky; Kuleshov, Sergey; Hakobyan, Hayk; Toro, Alam; Brooks, William K.; Rios, Rene

    2014-03-01

    The novel Hamamatsu Multi-Pixel Photon Counter (MPPC) S12045(X) is an array of 16 individual 3×3 mm2 MPPC devices each with 3600 Geiger-mode Avalanche Photodiode pixels of 50×50 μm2. Each MPPC in the array operates at a reverse bias of approximately 70 V. This paper summarizes our characterization of MPPC arrays used in the GlueX experiment in Hall D at Thomas Jefferson National Accelerator Facility (Jefferson Lab). We studied the main features of each of the 16 MPPC array channels for 2800 MPPC arrays at several different temperatures. Two measurement stations were built to extract gain, breakdown voltage, photon detection efficiency, optical crosstalk and dark rate for each of the 44 800 MPPC array channels at each temperature setting. The hardware and the data analysis are described, and new analytical expressions for the mean number of photoelectrons and optical crosstalk are presented, as well as systematic trends of the performance parameters.

  17. Novel Hamamatsu Multi-Pixel Photon Counter (MPPC) array studies for the GlueX experiment: New results

    Energy Technology Data Exchange (ETDEWEB)

    Soto, Orlando; Rojas, Rimsky; Kuleshov, Sergey; Hakobyan, Hayk, E-mail: hayk.hakobyan@usm.cl; Toro, Alam; Brooks, William K.; Rios, Rene

    2014-03-01

    The novel Hamamatsu Multi-Pixel Photon Counter (MPPC) S12045(X) is an array of 16 individual 3×3 mm{sup 2} MPPC devices each with 3600 Geiger-mode Avalanche Photodiode pixels of 50×50 μm{sup 2}. Each MPPC in the array operates at a reverse bias of approximately 70 V. This paper summarizes our characterization of MPPC arrays used in the GlueX experiment in Hall D at Thomas Jefferson National Accelerator Facility (Jefferson Lab). We studied the main features of each of the 16 MPPC array channels for 2800 MPPC arrays at several different temperatures. Two measurement stations were built to extract gain, breakdown voltage, photon detection efficiency, optical crosstalk and dark rate for each of the 44 800 MPPC array channels at each temperature setting. The hardware and the data analysis are described, and new analytical expressions for the mean number of photoelectrons and optical crosstalk are presented, as well as systematic trends of the performance parameters.

  18. The charge pump PLL clock generator designed for the 1.56 ns bin size time-to-digital converter pixel array of the Timepix3 readout ASIC

    CERN Document Server

    Fu, Y et al.

    2014-01-01

    Timepix3 is a newly developed pixel readout chip which is expected to be operated in a wide range of gaseous and silicon detectors. It is made of 256×256 pixels organized in a square pixel-array with 55 µm pitch. Oscillators running at 640 MHz are distributed across the pixel-array and allow for a highly accurate measurement of the arrival time of a hit. This paper concentrates on a low-jitter phase locked loop (PLL) that is located in the chip periphery. This PLL provides a control voltage which regulates the actual frequency of the individual oscillators, allowing for compensation of process, voltage, and temperature variations.

  19. Theoretical investigation of the noise performance of active pixel imaging arrays based on polycrystalline silicon thin film transistors.

    Science.gov (United States)

    Koniczek, Martin; Antonuk, Larry E; El-Mohri, Youcef; Liang, Albert K; Zhao, Qihua

    2017-07-01

    Active matrix flat-panel imagers, which typically incorporate a pixelated array with one a-Si:H thin-film transistor (TFT) per pixel, have become ubiquitous by virtue of many advantages, including large monolithic construction, radiation tolerance, and high DQE. However, at low exposures such as those encountered in fluoroscopy, digital breast tomosynthesis and breast computed tomography, DQE is degraded due to the modest average signal generated per interacting x-ray relative to electronic additive noise levels of ~1000 e, or greater. A promising strategy for overcoming this limitation is to introduce an amplifier into each pixel, referred to as the active pixel (AP) concept. Such circuits provide in-pixel amplification prior to readout as well as facilitate correlated multiple sampling, enhancing signal-to-noise and restoring DQE at low exposures. In this study, a methodology for theoretically investigating the signal and noise performance of imaging array designs is introduced and applied to the case of AP circuits based on low-temperature polycrystalline silicon (poly-Si), a semiconductor suited to manufacture of large area, radiation tolerant arrays. Computer simulations employing an analog circuit simulator and performed in the temporal domain were used to investigate signal characteristics and major sources of electronic additive noise for various pixel amplifier designs. The noise sources include photodiode shot noise and resistor thermal noise, as well as TFT thermal and flicker noise. TFT signal behavior and flicker noise were parameterized from fits to measurements performed on individual poly-Si test TFTs. The performance of three single-stage and three two-stage pixel amplifier designs were investigated under conditions relevant to fluoroscopy. The study assumes a 20 × 20 cm(2) , 150 μm pitch array operated at 30 fps and coupled to a CsI:Tl x-ray converter. Noise simulations were performed as a function of operating conditions, including

  20. Photon-counting hexagonal pixel array CdTe detector: Spatial resolution characteristics for image-guided interventional applications

    Energy Technology Data Exchange (ETDEWEB)

    Vedantham, Srinivasan; Shrestha, Suman; Karellas, Andrew, E-mail: andrew.karellas@umassmed.edu; Shi, Linxi; Gounis, Matthew J. [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States); Bellazzini, Ronaldo; Spandre, Gloria; Brez, Alessandro; Minuti, Massimo [Istituto Nazionale di Fisica Nucleare (INFN), Pisa 56127, Italy and Pixirad Imaging Counters s.r.l., L. Pontecorvo 3, Pisa 56127 (Italy)

    2016-05-15

    Purpose: High-resolution, photon-counting, energy-resolved detector with fast-framing capability can facilitate simultaneous acquisition of precontrast and postcontrast images for subtraction angiography without pixel registration artifacts and can facilitate high-resolution real-time imaging during image-guided interventions. Hence, this study was conducted to determine the spatial resolution characteristics of a hexagonal pixel array photon-counting cadmium telluride (CdTe) detector. Methods: A 650 μm thick CdTe Schottky photon-counting detector capable of concurrently acquiring up to two energy-windowed images was operated in a single energy-window mode to include photons of 10 keV or higher. The detector had hexagonal pixels with apothem of 30 μm resulting in pixel pitch of 60 and 51.96 μm along the two orthogonal directions. The detector was characterized at IEC-RQA5 spectral conditions. Linear response of the detector was determined over the air kerma rate relevant to image-guided interventional procedures ranging from 1.3 nGy/frame to 91.4 μGy/frame. Presampled modulation transfer was determined using a tungsten edge test device. The edge-spread function and the finely sampled line spread function accounted for hexagonal sampling, from which the presampled modulation transfer function (MTF) was determined. Since detectors with hexagonal pixels require resampling to square pixels for distortion-free display, the optimal square pixel size was determined by minimizing the root-mean-squared-error of the aperture functions for the square and hexagonal pixels up to the Nyquist limit. Results: At Nyquist frequencies of 8.33 and 9.62 cycles/mm along the apothem and orthogonal to the apothem directions, the modulation factors were 0.397 and 0.228, respectively. For the corresponding axis, the limiting resolution defined as 10% MTF occurred at 13.3 and 12 cycles/mm, respectively. Evaluation of the aperture functions yielded an optimal square pixel size of 54

  1. Monitoring LSO/LYSO Crystal Based Calorimeters

    Science.gov (United States)

    Yang, Fan; Zhang, Liyuan; Zhu, Ren-Yuan

    2015-02-01

    Precision light monitoring is important for keeping excellent energy resolution promised by LSO/LYSO crystals in severe radiation environment. In this paper, we report an investigation on the wavelength choice for monitoring LYSO crystal based calorimeters. Gamma-ray induced absorption and light output loss were measured for 20 cm long crystals from five different vendors. Monitoring sensitivity and divergence between crystals from different vendors were investigated. The pros and cons of two monitoring approaches using emission and excitation light and their practical implementation for a LYSO/W Shashlik test beam matrix are discussed.

  2. GEM400: A front-end chip based on capacitor-switch array for pixel-based GEM detector

    Science.gov (United States)

    Li, H. S.; Jiang, X. S.; Liu, G.; Wang, N.; Sheng, H. Y.; Zhuang, B. A.; Zhao, J. W.

    2012-03-01

    The upgrade of Beijing Synchrotron Radiation Facility (BSRF) needs two-dimensional position-sensitive detection equipment to improve the experimental performance. Gas Electron Multiplier (GEM) detector, in particular, pixel-based GEM detector has good application prospects in the domain of synchrotron radiation. The read-out of larger scale pixel-based GEM detector is difficult for the high density of the pixels (PAD for collecting electrons). In order to reduce the number of cables, this paper presents a read-out scheme for pixel-based GEM detector, which is based on System-in-Package technology and ASIC technology. We proposed a circuit structure based on capacitor switch array circuit, and design a chip GEM400, which is a 400 channels ASIC. The proposed circuit can achieve good stability and low power dissipation. The chip is implemented in a 0.35μm CMOS process. The basic functional circuitry in ths chip includes analog switch, analog buffer, voltage amplifier, bandgap and control logic block, and the layout of this chip takes 5mm × 5mm area. The simulation results show that the chip can allow the maximum amount of input charge 70pC on the condition of 100pF external integrator capacitor. Besides, the chip has good channel uniformity (INL is better than 0.1%) and lower power dissipation.

  3. 256-pixel microcalorimeter array for high-resolution γ-ray spectroscopy of mixed-actinide materials

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, R., E-mail: rwinkler@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM (United States); Hoover, A.S.; Rabin, M.W. [Los Alamos National Laboratory, Los Alamos, NM (United States); Bennett, D.A.; Doriese, W.B.; Fowler, J.W.; Hays-Wehle, J.; Horansky, R.D.; Reintsema, C.D.; Schmidt, D.R.; Vale, L.R.; Ullom, J.N. [National Institute of Standards and Technology, Boulder, CO (United States)

    2015-01-11

    The application of cryogenic microcalorimeter detectors to γ-ray spectroscopy allows for measurements with unprecedented energy resolution. These detectors are ideally suited for γ-ray spectroscopy applications for which the measurement quality is limited by the spectral overlap of many closely spaced transitions using conventional detector technologies. The non-destructive analysis of mixed-isotope Pu materials is one such application where the precision can be potentially improved utilizing microcalorimeter detectors compared to current state-of-the-art high-purity Ge detectors (HPGe). The LANL-NIST γ-ray spectrometer, a 256-pixel microcalorimeter array based on transition-edge sensors (TESs), was recently commissioned and used to collect data on a variety of Pu isotopic standards to characterize the instrument performance. These measurements represent the first time the simultaneous readout of all 256 pixels for measurements of mixed-isotope Pu materials has been achieved. The LANL-NIST γ-ray spectrometer has demonstrated an average pixel resolution of 55 eV full-width-at-half-maximum at 100 keV, nearly an order of magnitude better than HPGe detectors. Some challenges of the analysis of many-channel ultra-high resolution data and the techniques used to produce quality spectra for isotopic analysis will be presented. The LANL-NIST γ-ray spectrometer has also demonstrated stable operation and obtained high resolution measurements at total array event rates beyond 1 kHz. For a total event rate of 1.25 kHz, approximately 5.6 cps/pixel, a 72.2 eV average FWHM for the 103 keV photopeak of {sup 153}Gd was achieved.

  4. Advances in Small Pixel TES-Based X-Ray Microcalorimeter Arrays for Solar Physics and Astrophysics

    Science.gov (United States)

    Bandler, S. R.; Adams, J. S.; Bailey, C. N.; Busch, S. E.; Chervenak, J. A.; Eckart, M. E.; Ewin, A. E.; Finkbeiner, F. M.; Kelley, R. L.; Kelly, D. P.; Kilbourne, C. A.; Porst, J.-P.; Porter, F. S.; Sadleir, J. E.; Smith, S. J.; Wassell, E. J.

    2012-01-01

    We are developing small-pixel transition-edge-sensor (TES) for solar physics and astrophysics applications. These large format close-packed arrays are fabricated on solid silicon substrates and are designed to accommodate count-rates of up to a few hundred counts/pixel/second at a FWHM energy resolution approximately 2 eV at 6 keV. We have fabricated versions that utilize narrow-line planar and stripline wiring. We present measurements of the performance and uniformity of kilo-pixel arrays, incorporating TESs with single 65-micron absorbers on a 7s-micron pitch, as well as versions with more than one absorber attached to the TES, 4-absorber and 9-absorber "Hydras". We have also fabricated a version of this detector optimized for lower energies and lower count-rate applications. These devices have a lower superconducting transition temperature and are operated just above the 40mK heat sink temperature. This results in a lower heat capacity and low thermal conductance to the heat sink. With individual single pixels of this type we have achieved a FWHM energy resolution of 0.9 eV with 1.5 keV Al K x-rays, to our knowledge the first x-ray microcalorimeter with sub-eV energy resolution. The 4-absorber and 9-absorber versions of this type achieved FWHM energy resolutions of 1.4 eV and 2.1 eV at 1.5 keV respectively. We will discuss the application of these devices for new astrophysics mission concepts.

  5. Characterization of CdTe sensors with Schottky contacts coupled to charge-integrating pixel array detectors for X-ray science

    Science.gov (United States)

    Becker, J.; Tate, M. W.; Shanks, K. S.; Philipp, H. T.; Weiss, J. T.; Purohit, P.; Chamberlain, D.; Ruff, J. P. C.; Gruner, S. M.

    2016-12-01

    Pixel Array Detectors (PADs) consist of an x-ray sensor layer bonded pixel-by-pixel to an underlying readout chip. This approach allows both the sensor and the custom pixel electronics to be tailored independently to best match the x-ray imaging requirements. Here we present characterizations of CdTe sensors hybridized with two different charge-integrating readout chips, the Keck PAD and the Mixed-Mode PAD (MM-PAD), both developed previously in our laboratory. The charge-integrating architecture of each of these PADs extends the instantaneous counting rate by many orders of magnitude beyond that obtainable with photon counting architectures. The Keck PAD chip consists of rapid, 8-frame, in-pixel storage elements with framing periods detector, the MM-PAD, has an extended dynamic range by utilizing an in-pixel overflow counter coupled with charge removal circuitry activated at each overflow. This allows the recording of signals from the single-photon level to tens of millions of x-rays/pixel/frame while framing at 1 kHz. Both detector chips consist of a 128 × 128 pixel array with (150 μm)2 pixels.

  6. High-speed imaging at high x-ray energy: CdTe sensors coupled to charge-integrating pixel array detectors

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Julian; Tate, Mark W.; Shanks, Katherine S.; Philipp, Hugh T.; Weiss, Joel T.; Purohit, Prafull [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Chamberlain, Darol [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M., E-mail: smg26@cornell.edu [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States)

    2016-07-27

    Pixel Array Detectors (PADs) consist of an x-ray sensor layer bonded pixel-by-pixel to an underlying readout chip. This approach allows both the sensor and the custom pixel electronics to be tailored independently to best match the x-ray imaging requirements. Here we describe the hybridization of CdTe sensors to two different charge-integrating readout chips, the Keck PAD and the Mixed-Mode PAD (MM-PAD), both developed previously in our laboratory. The charge-integrating architecture of each of these PADs extends the instantaneous counting rate by many orders of magnitude beyond that obtainable with photon counting architectures. The Keck PAD chip consists of rapid, 8-frame, in-pixel storage elements with framing periods <150 ns. The second detector, the MM-PAD, has an extended dynamic range by utilizing an in-pixel overflow counter coupled with charge removal circuitry activated at each overflow. This allows the recording of signals from the single-photon level to tens of millions of x-rays/pixel/frame while framing at 1 kHz. Both detector chips consist of a 128×128 pixel array with (150 µm){sup 2} pixels.

  7. Transition-edge sensor pixel parameter design of the microcalorimeter array for the x-ray integral field unit on Athena

    Science.gov (United States)

    Smith, S. J.; Adams, J. S.; Bandler, S. R.; Betancourt-Martinez, G. L.; Chervenak, J. A.; Chiao, M. P.; Eckart, M. E.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Miniussi, A. R.; Porter, F. S.; Sadleir, J. E.; Sakai, K.; Wakeham, N. A.; Wassell, E. J.; Yoon, W.; Bennett, D. A.; Doriese, W. B.; Fowler, J. W.; Hilton, G. C.; Morgan, K. M.; Pappas, C. G.; Reintsema, C. N.; Swetz, D. S.; Ullom, J. N.; Irwin, K. D.; Akamatsu, H.; Gottardi, L.; den Hartog, R.; Jackson, B. D.; van der Kuur, J.; Barret, D.; Peille, P.

    2016-07-01

    The focal plane of the X-ray integral field unit (X-IFU) for ESA's Athena X-ray observatory will consist of 4000 transition edge sensor (TES) x-ray microcalorimeters optimized for the energy range of 0.2 to 12 keV. The instrument will provide unprecedented spectral resolution of 2.5 eV at energies of up to 7 keV and will accommodate photon fluxes of 1 mCrab (90 cps) for point source observations. The baseline configuration is a uniform large pixel array (LPA) of 4.28" pixels that is read out using frequency domain multiplexing (FDM). However, an alternative configuration under study incorporates an 18 × 18 small pixel array (SPA) of 2" pixels in the central 36" region. This hybrid array configuration could be designed to accommodate higher fluxes of up to 10 mCrab (900 cps) or alternately for improved spectral performance (report on the TES pixel designs that are being optimized to meet these proposed LPA and SPA configurations. In particular we describe details of how important TES parameters are chosen to meet the specific mission criteria such as energy resolution, count-rate and quantum efficiency, and highlight performance trade-offs between designs. The basis of the pixel parameter selection is discussed in the context of existing TES arrays that are being developed for solar and x-ray astronomy applications. We describe the latest results on DC biased diagnostic arrays as well as large format kilo-pixel arrays and discuss the technical challenges associated with integrating different array types on to a single detector die.

  8. Comparison of three resistor network division circuits for the readout of 4×4 pixel SiPM arrays

    Energy Technology Data Exchange (ETDEWEB)

    Stratos, David [Department of Medical Instruments Technology, Technological Educational Institute of Athens (Greece); Maria, Georgiou [Department of Medical Instruments Technology, Technological Educational Institute of Athens (Greece); Department of Nuclear Medicine, Medical School, University of Thessaly (Greece); Eleftherios, Fysikopoulos [Department of Medical Instruments Technology, Technological Educational Institute of Athens (Greece); School of Electrical and Computer Engineering, National Technical University of Athens, Athens (Greece); George, Loudos, E-mail: gloudos@teiath.gr [Department of Medical Instruments Technology, Technological Educational Institute of Athens (Greece)

    2013-02-21

    The purpose of this study is to investigate the behavior of a flexible SensL's silicon photomultiplier array (SPMArray4) photodetector for possible applications in PET imaging. We have designed and evaluated three different resistor network division circuits to read out the signal outputs of a 4×4 pixel SiPM array. We have applied firstly (i) a symmetric resistive voltage division circuit, secondly (ii) a symmetric resistive charge division circuit and thirdly (iii) a charge division multiplexing resistor network reducing the 16 pixel outputs to 4 position signals. In the first circuit the SensL SPMArray4-A0 preamplification electronics and a SPMArray4-A1 evaluation board providing the 16 pixels voltage outputs were used, before the symmetric resistive voltage network. We reduced the 16 voltage signals firstly to 4X and 4Y coordinate signals. Then those signals were further reduced to 2X and 2Y position signals connected via a resistor network. In the second readout circuit we have used the same technique but without the preamplification stage. The third circuit is based on a discretized positioning circuit, which multiplexes the 16 signals from the SiPM array to 4 position signals. The 4 position signals (Xa, Xb, Yc and Yd) were digitized using a free running sampling technique. An FPGA (Spartan 6 LX16) was used for triggering and signal processing of the pulses. We acquired raw images and energy histograms of a BGO and a CsI:Na pixilated scintillator under {sup 22}Na excitation. A clear visualization of the discrete 2×2×5 mm{sup 3} pixilated BGO scintillator elements as well as the 1×1×5 mm{sup 3} pixilated CsI:Na crystal array was achieved with all applied readout circuits. The symmetric resistive charge division circuit provides higher peak to valley ratio than the other readout circuits. Τhe sensitivity and the energy resolution remained almost constant for the three circuits.

  9. A 4k-Pixel CTIA Readout for Far IR Photodetector Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to design a low noise, two-side buttable, 64x64 readout multiplexer with the following key design features: 1- By far the largest readout array developed...

  10. Fourier transform acousto-optic imaging with a custom-designed CMOS smart-pixels array.

    Science.gov (United States)

    Barjean, Kinia; Contreras, Kevin; Laudereau, Jean-Baptiste; Tinet, Éric; Ettori, Dominique; Ramaz, François; Tualle, Jean-Michel

    2015-03-01

    We report acousto-optic imaging (AOI) into a scattering medium using a Fourier Transform (FT) analysis to achieve axial resolution. The measurement system was implemented using a CMOS smart-pixels sensor dedicated to the real-time analysis of speckle patterns. This first proof-of-principle of FT-AOI demonstrates some of its potential advantages, with a signal-to-noise ratio comparable to the one obtained without axial resolution, and with an acquisition rate compatible with a use on living biological tissue.

  11. Design and numerical simulation of a pixelated full stokes micropolarizer array

    Science.gov (United States)

    Wang, Changjiang; Hu, Jingpei; Wang, Chinhua

    2016-10-01

    In this paper, we propose and demonstrate numerically a pixelated component for full Stokes polarization imaging by integrating linear polarizers and circular polarizers on a single silicon chip working in near infrared band ( 1.6μm). The micro linear polarizers collect linear polarizing information from different orientations while the circular polarizers collect left-handed or right-handed circular polarization information such that full Stokes polarization imaging can be implemented on a single chip in real time. Numerical results show that the extinction ratio and TM transmission of linearly polarization can reach 45dB and 78%, respectively, with a linear metallic grating of period 300nm, and the dichroism of left-handed and right-handed circular polarization can reach 55% with a plasmonic chiral structure that is compatible with linear gratings in terms of structure and fabrication. The proposed structure is of significance in real-time full Stokes polarization imaging.

  12. Development of a fast pixel array detector for use in microsecond time-resolved x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Barna, S.L.; Gruner, S.M.; Shepherd, J.A. [Princeton Univ., NJ (United States)] [and others

    1995-08-01

    A large-area pixel x-ray detector is being developed to collect eight successive frames of wide dynamic range two-dimensional images at 200kHz rates. Such a detector, in conjunction with a synchrotron radiation x-ray source, will enable time-resolved x-ray studies of proteins and other materials on time scales which have previously been inaccessible. The detector will consist of an array of fully-depleted 150 micron square diodes connected to a CMOS integrated electronics layer with solder bump-bonding. During each framing period, the current resulting from the x-rays stopped in the diodes is integrated in the electronics layer, and then stored in one of eight storage capacitors underneath the pixel. After the last frame, the capacitors are read out at standard data transmission rates. The detector has been designed for a well-depth of at least 10,000 x-rays (at 20keV), and a noise level of one x-ray. Ultimately, the authors intend to construct a detector with over one million pixels (1024 by 1024). They present the results of their development effort and various features of the design. The electronics design is discussed, with special attention to the performance requirements. The choice and design of the detective diodes, as they relate to x-ray stopping power and charge collection, are presented. An analysis of various methods of bump bonding is also presented. Finally, the authors discuss the possible need for a radiation-blocking layer, to be placed between the electronics and the detective layer, and various methods they have pursued in the construction of such a layer.

  13. SuperCam, a 64-pixel heterodyne imaging array for the 870 micron atmospheric window

    CERN Document Server

    Groppi, C; Kulesa, C; Pütz, P; Golish, D; Gensheimer, P; Hedden, A; Bussmann, S; Weinreb, S; Kuiper, T; Kooi, J; Jones, G; Bardin, J; Mani, H S; Lichtenberger, A; Narayanan, G; Groppi, Christopher; Walker, Christopher; Kulesa, Craig; Puetz, Patrick; Golish, Dathon; Gensheimer, Paul; Hedden, Abigail; Bussmann, Shane; Weinreb, Sander; Kuiper, Thomas; Kooi, Jacob; Jones, Glenn; Bardin, Joseph; Mani, Hamdi; Lichtenberger, Arthur; Narayanan, Gopal

    2006-01-01

    We report on the development of SuperCam, a 64 pixel, superheterodyne camera designed for operation in the astrophysically important 870 micron atmospheric window. SuperCam will be used to answer fundamental questions about the physics and chemistry of molecular clouds in the Galaxy and their direct relation to star and planet formation. The advent of such a system will provide an order of magnitude increase in mapping speed over what is now available and revolutionize how observational astronomy is performed in this important wavelength regime. Unlike the situation with bolometric detectors, heterodyne receiver systems are coherent, retaining information about both the amplitude and phase of the incident photon stream. From this information a high resolution spectrum of the incident light can be obtained without multiplexing. SuperCam will be constructed by stacking eight, 1x8 rows of fixed tuned, SIS mixers. The IF output of each mixer will be connected to a low-noise, broadband MMIC amplifier integrated in...

  14. LSO background radiation as a transmission source using time of flight.

    Science.gov (United States)

    Rothfuss, Harold; Panin, Vladimir; Moor, Andrew; Young, John; Hong, Inki; Michel, Christian; Hamill, James; Casey, Michael

    2014-09-21

    LSO scintillators (Lu2Sio5:Ce) have a background radiation which originates from the isotope Lu-176 that is present in natural occurring lutetium. The decay that occurs in this isotope is a beta decay that is in coincidence with cascade gamma emissions with energies of 307,202 and 88 keV. The coincidental nature of the beta decay with the gamma emissions allow for separation of emission data originating from a positron annihilation event from transmission type data from the Lu-176 beta decay. By using the time of flight information, and information of the chord length between two LSO pixels in coincidence as a result of a beta emission and emitted gamma, a second time window can be set to observe transmission events simultaneously to emission events. Using the time when the PET scanner is not actively acquiring positron emission data, a continuous blank can be acquired and used to reconstruct a transmission image. With this blank and the measured transmission data, a transmission image can be reconstructed. This reconstructed transmission image can be used to perform emission data corrections such as attenuation correction and scatter corrections or starting images for algorithms that estimate emission and attenuation simultaneously. It is observed that the flux of the background activity is high enough to create useful transmission images with an acquisition time of 10 min.

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

    Science.gov (United States)

    Petilli, Eugene

    2016-09-01

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

  16. Characterization of CdTe Sensors with Schottky Contacts Coupled to Charge-Integrating Pixel Array Detectors for X-Ray Science

    CERN Document Server

    Becker, Julian; Shanks, Katherine S; Philipp, Hugh T; Weiss, Joel T; Purohit, Prafull; Chamberlain, Darol; Ruff, Jacob P C; Gruner, Sol M

    2016-01-01

    Pixel Array Detectors (PADs) consist of an x-ray sensor layer bonded pixel-by-pixel to an underlying readout chip. This approach allows both the sensor and the custom pixel electronics to be tailored independently to best match the x-ray imaging requirements. Here we present characterizations of CdTe sensors hybridized with two different charge-integrating readout chips, the Keck PAD and the Mixed-Mode PAD (MM-PAD), both developed previously in our laboratory. The charge-integrating architecture of each of these PADs extends the instantaneous counting rate by many orders of magnitude beyond that obtainable with photon counting architectures. The Keck PAD chip consists of rapid, 8-frame, in-pixel storage elements with framing periods $<$150 ns. The second detector, the MM-PAD, has an extended dynamic range by utilizing an in-pixel overflow counter coupled with charge removal circuitry activated at each overflow. This allows the recording of signals from the single-photon level to tens of millions of x-rays/...

  17. High-speed x-ray imaging with the Keck pixel array detector (Keck PAD) for time-resolved experiments at synchrotron sources

    Energy Technology Data Exchange (ETDEWEB)

    Philipp, Hugh T., E-mail: htp2@cornell.edu; Tate, Mark W.; Purohit, Prafull; Shanks, Katherine S.; Weiss, Joel T. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY (United States); Chamberlain, Darol; Gruner, Sol M. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY (United States)

    2016-07-27

    Modern storage rings are readily capable of providing intense x-ray pulses, tens of picoseconds in duration, millions of times per second. Exploiting the temporal structure of these x-ray sources opens avenues for studying rapid structural changes in materials. Many processes (e.g. crack propagation, deformation on impact, turbulence, etc.) differ in detail from one sample trial to the next and would benefit from the ability to record successive x-ray images with single x-ray sensitivity while framing at 5 to 10 MHz rates. To this end, we have pursued the development of fast x-ray imaging detectors capable of collecting bursts of images that enable the isolation of single synchrotron bunches and/or bunch trains. The detector technology used is the hybrid pixel array detector (PAD) with a charge integrating front-end, and high-speed, in-pixel signal storage elements. A 384×256 pixel version, the Keck-PAD, with 150 µm × 150 µm pixels and 8 dedicated in-pixel storage elements is operational, has been tested at CHESS, and has collected data for compression wave studies. An updated version with 27 dedicated storage capacitors and identical pixel size has been fabricated.

  18. Submillisecond X-ray photon correlation spectroscopy from a pixel array detector with fast dual gating and no readout dead-time.

    Science.gov (United States)

    Zhang, Qingteng; Dufresne, Eric M; Grybos, Pawel; Kmon, Piotr; Maj, Piotr; Narayanan, Suresh; Deptuch, Grzegorz W; Szczygiel, Robert; Sandy, Alec

    2016-05-01

    Small-angle scattering X-ray photon correlation spectroscopy (XPCS) studies were performed using a novel photon-counting pixel array detector with dual counters for each pixel. Each counter can be read out independently from the other to ensure there is no readout dead-time between the neighboring frames. A maximum frame rate of 11.8 kHz was achieved. Results on test samples show good agreement with simple diffusion. The potential of extending the time resolution of XPCS beyond the limit set by the detector frame rate using dual counters is also discussed.

  19. Submillisecond X-ray photon correlation spectroscopy from a pixel array detector with fast dual gating and no readout dead-time

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qingteng; Dufresne, Eric M.; Grybos, Pawel; Kmon, Piotr; Maj, Piotr; Narayanan, Suresh; Deptuch, Grzegorz W.; Szczygiel, Robert; Sandy, Alec

    2016-04-19

    Small-angle scattering X-ray photon correlation spectroscopy (XPCS) studies were performed using a novel photon-counting pixel array detector with dual counters for each pixel. Each counter can be read out independently from the other to ensure there is no readout dead-time between the neighboring frames. A maximum frame rate of 11.8 kHz was achieved. Results on test samples show good agreement with simple diffusion. The potential of extending the time resolution of XPCS beyond the limit set by the detector frame rate using dual counters is also discussed.

  20. A novel epitaxially grown LSO-based thin-film scintillator for micro-imaging using hard synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Douissard, P.A.; Martin, T.; Chevalier, V.; Rack, A. [European Synchrotron Radiat Facil, F-38043 Grenoble, (France); Cecilia, A.; Baumbach, T.; Rack, A. [Karlsruhe Inst Technol ANKA, D-76021 Karlsruhe, (Germany); Couchaud, M. [CEA LETI, F-38054 Grenoble, (France); Dupre, K. [FEE GmbH, D-55743 Idar Oberstein, (Germany); Kuhbacher, M. [Helmholtz Zentrum Berlin Mat and Energie, D-14109 Berlin, (Germany)

    2010-07-01

    The efficiency of high-resolution pixel detectors for hard X-rays is nowadays one of the major criteria which drives the feasibility of imaging experiments and in general the performance of an experimental station for synchrotron-based microtomography and radiography. Here the luminescent screen used for the indirect detection is focused on in order to increase the detective quantum efficiency a novel scintillator based on doped Lu{sub 2}SiO{sub 5} (LSO), epitaxially grown as thin film via the liquid phase epitaxy technique. It is shown that, by using adapted growth and doping parameters as well as a dedicated substrate, the scintillation behaviour of a LSO-based thin crystal together with the high stopping power of the material allows for high-performance indirect X-ray detection. In detail, the conversion efficiency, the radioluminescence spectra, the optical absorption spectra under UV/visible-light and the afterglow are investigated. A set-up to study the effect of the thin-film scintillator's temperature on its conversion efficiency is described as well it delivers knowledge which is important when working with higher photon flux densities and the corresponding high heat load on the material. Additionally, X-ray imaging systems based on different diffraction-limited visible-light optics and CCD cameras using among others LSO-based thin film are compared. Finally, the performance of the LSO thin film is illustrated by imaging a honey bee leg, demonstrating the value of efficient high-resolution computed tomography for life sciences. (authors)

  1. Listeriolysin genes: complete sequence of ilo from Listeria ivanovii and of lso from Listeria seeligeri.

    Science.gov (United States)

    Haas, A; Dumbsky, M; Kreft, J

    1992-02-28

    The complete DNA sequences coding for the thiol-activated cytolysins from Listeria ivanovii, ivanolysin O (ILO) and for seeligerolysin O (LSO) from Listeria seeligeri have been determined. The deduced amino acid sequences revealed that: (i) the primary translation products comprise 528 (ILO) and 530 (LSO) amino acids, respectively, (ii) ILO contains two cysteines, LSO has a substitution in the conserved cysteine motif.

  2. Characterization of LFS-3 scintillator in comparison with LSO

    Energy Technology Data Exchange (ETDEWEB)

    Grodzicka, M., E-mail: M.Grodzicka@ipj.gov.pl [Soltan Institute for Nuclear Studies, PL 05-400 Otwock-Swierk (Poland); Moszynski, M.; Szczesniak, T.; Syntfeld-Kazuch, A.; Swiderski, L. [Soltan Institute for Nuclear Studies, PL 05-400 Otwock-Swierk (Poland); Zerrouk, A.F. [Zecotek Photonics Inc, 20 Science Park Road, 01-23/25, Teletech Park, Science Park II, Singapore 117674 (Singapore); Owczarczyk, J. [Compart Medical Systems, PL 04-703 Warsaw, Pozaryskiego 28 (Poland)

    2011-10-01

    Performance of Lutetium Fine Silicate (LFS-3) scintillator in gamma-ray spectrometry has been investigated in comparison with the well known LSO crystal. The tests covered measurements of light output in terms of number of photoelectrons, energy resolution and non-proportionality. Time resolution was measured in coincidence experiments with 511 keV annihilation quanta from a {sup 22}Na gamma source. Decay time constants of the light pulse were calculated on the basis of timing spectra obtained using Thomas-Bollinger single photon method. Afterglow was measured about 30 ms after the crystal was irradiated by a strong 13.9 GBq {sup 241}Am source. Improvement in the energy resolution for 662 keV {gamma}-rays from {sup 137}Cs, shorter decay time constants and better time resolution were observed in case of LFS-3, when compared with LSO. For LFS-3 energy resolution for 662 keV from {sup 137}Cs, decay time and time resolution were equal to about 7.66{+-}0.23%, 40.5{+-}1.2 ns and 161{+-}5 ps, respectively, whereas for LSO the same parameters were equal to 8.13{+-}0.23%, 43.9{+-}1.3 ns and 173{+-}5 ps, respectively. The study showed that LFS-3 crystal is an excellent substitute for LSO crystal.

  3. Design and performance of large-pixel-size high-fill-fraction TES arrays for future X-ray astrophysics missions

    Energy Technology Data Exchange (ETDEWEB)

    Figueroa-Feliciano, E. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)]. E-mail: enectali@mit.edu; Bandler, S.R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Chervenak, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Finkbeiner, F. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Iyomoto, N. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kelley, R.L. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kilbourne, C.A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Porter, F.S. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Saab, T. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sadleir, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); White, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2006-04-15

    We have designed, modeled, fabricated and tested a 600{mu}m high-fill-fraction microcalorimeter array that will be a good match to the requirements of future X-ray missions. Our devices use transition-edge sensors coupled to overhanging bismuth/copper absorbers to produce arrays with 97% or higher fill fraction. An extensive modeling effort was undertaken in order to accommodate large pixel sizes (500-1000{mu}m) and maintain the best energy resolution possible. The finite thermalization time of the large absorber and the associated position dependence of the pulse shape on absorption position constrain the time constants of the system given a desired energy-resolution performance. We show the results of our analysis and our new pixel design, consisting of a novel TES-on-the-side architecture which creates a controllable TES-absorber conductance.

  4. Signal dependence of inter-pixel capacitance in hybridized HgCdTe H2RG arrays for use in James Webb space telescope's NIRcam

    Science.gov (United States)

    Donlon, Kevan; Ninkov, Zoran; Baum, Stefi

    2016-08-01

    Interpixel capacitance (IPC) is a deterministic electronic coupling by which signal generated in one pixel is measured in neighboring pixels. Examination of dark frames from test NIRcam arrays corroborates earlier results and simulations illustrating a signal dependent coupling. When the signal on an individual pixel is larger, the fractional coupling to nearest neighbors is lesser than when the signal is lower. Frames from test arrays indicate a drop in average coupling from approximately 1.0% at low signals down to approximately 0.65% at high signals depending on the particular array in question. The photometric ramifications for this non-uniformity are not fully understood. This non-uniformity intro-duces a non-linearity in the current mathematical model for IPC coupling. IPC coupling has been mathematically formalized as convolution by a blur kernel. Signal dependence requires that the blur kernel be locally defined as a function of signal intensity. Through application of a signal dependent coupling kernel, the IPC coupling can be modeled computationally. This method allows for simultaneous knowledge of the intrinsic parameters of the image scene, the result of applying a constant IPC, and the result of a signal dependent IPC. In the age of sub-pixel precision in astronomy these effects must be properly understood and accounted for in order for the data to accurately represent the object of observation. Implementation of this method is done through python scripted processing of images. The introduction of IPC into simulated frames is accomplished through convolution of the image with a blur kernel whose parameters are themselves locally defined functions of the image. These techniques can be used to enhance the data processing pipeline for NIRcam.

  5. Development of a large-area monolithic 4x4 MPPC array for a future PET scanner employing pixelized Ce:LYSO and Pr:LuAG crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kato, T., E-mail: katou.frme.8180@asagi.waseda.j [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Kataoka, J.; Nakamori, T.; Miura, T.; Matsuda, H. [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Sato, K.; Ishikawa, Y.; Yamamura, K.; Kawabata, N. [Solid State Division, Hamamatsu Photonics K. K., 1126-1, Ichino-cho, Hamamatsu, Shizuoka (Japan); Ikeda, H.; Sato, G. [ISAS/JAXA, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa (Japan); Kamada, K. [Materials Research Laboratory, Furukawa Co., Ltd., 1-25-13, Kannondai, Tsukuba, Ibaraki 305-0856 (Japan)

    2011-05-11

    We have developed a new type of large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of a 4x4 matrix of 3x3 mm{sup 2} pixels. Each pixel comprises 3600 Geiger mode avalanche photodiodes (APDs) that achieve an average gain of 9.68x10{sup 5} at 71.9 V at 0 {sup o}C with variations of only {+-}7.2% over 4x4 pixels. Excellent uniformity was also obtained for photon detection efficiencies (PDE) of {+-}6.4%, whilst dark count rates at the single photoelectron (1 p.e.) level amounted to {approx_equal}2Mcps/pixel, measured at 0 {sup o}C. As the first step toward using the device in scintillation photon detectors, we fabricated a prototype gamma-ray camera consisting of an MPPC array optically coupled with a scintillator matrix, namely a 4x4 array of 3x3 x10 mm{sup 3} crystals. Specifically, we tested the performance with Ce-doped (Lu, Y){sub 2}(SiO{sub 4})O (Ce:LYSO), Pr-doped Lu{sub 3}Al{sub 5}O{sub 12} (Pr:LuAG) and 'surface coated' Pr:LuAG (Pr:LuAG (WLS)) matrices whereby the emission peak of Pr:LuAG was shifted from 310 to 420 nm via a wavelength shifter (WLS). Average energy resolutions of 13.83%, 14.70% and 13.96% (FWHM) were obtained for 662 keV gamma-rays, as measured at 0 {sup o}C with Ce:LYSO, Pr:LuAG and Pr:LuAG (WLS) scintillator matrices, respectively. We confirmed that the effective PDE for Pr:LuAG (WLS) had improved by more than 30% compared to original, non-coated Pr:LuAG matrix. These results suggest that a large-area monolithic MPPC array developed here could be promising for future medical imaging, particularly in positron emission tomography (PET).

  6. Factors influencing timing resolution in a commercial LSO PETcamera

    Energy Technology Data Exchange (ETDEWEB)

    Moses, William W.; Ullisch, Marcus

    2004-10-23

    The CPS Accel is a commercial PET camera based on a block detector with 64 LSO scintillator crystals (each 6.75 x 6.75 x 25 mm)read out with 4 photomultiplier tubes. The excellent timing resolution of LSO suggests that this camera might be used for time-of-flight (TOF) PET, thereby reducing the statistical noise significantly. Although the Accel achieves 3 ns coincidence resolution (a factor of two better than BGO-based PET cameras), its timing resolution is nearly an order of magnitude worse than that demonstrated with individual LSO crystals. This paper quantifies the effect on the timing of each component in the Accel timing chain to identify which components most limit the camera's timing resolution. The components in the timing chain are: the scintillator crystal, the photomultiplier tube (PMT), the constant fraction discriminator (CFD), and the time to digital converter (TDC). To measure the contribution of each component, we construct a single crystal test system with high-performance versions of these components. This system achieves 221 ps fwhm coincidence timing resolution, which is used as a baseline measurement. One of the high-performance components is replaced by a production component, the coincidence timing resolution is re-measured, and the difference between measurements is the contribution of that (production) component. We find that the contributions of the TDC, CFD, PMT, and scintillator are 2000 ps, 1354 ps, 422 ps, and 326 psfwhm respectively, and that the overall timing resolution scales like the square root of the amount of scintillation light detected by the PMT. Based on these measurements we predict that the limit for the coincidence timing resolution in a practical, commercial, LSO-based PET camera is 528ps fwhm.

  7. Evaluation of a photon-counting hybrid pixel detector array with a synchrotron X-ray source

    Science.gov (United States)

    Ponchut, C.; Visschers, J. L.; Fornaini, A.; Graafsma, H.; Maiorino, M.; Mettivier, G.; Calvet, D.

    2002-05-01

    A photon-counting hybrid pixel detector (Medipix-1) has been characterized using a synchrotron X-ray source. The detector consists of a readout ASIC with 64×64 independent photon-counting cells of 170×170 μm 2 pitch, bump-bonded to a 300 μm thick silicon sensor, read out by a PCIbus-based electronics, and a graphical user interface (GUI) software. The intensity and the energy tunability of the X-ray source allow characterization of the detector in the time, space, and energy domains. The system can be read out on external trigger at a frame rate of 100 Hz with 3 ms exposure time per frame. The detector response is tested up to more than 7×10 5 detected events/pixel/s. The point-spread response shows beam reveals no loss in sensitivity between adjacent pixels as could result from charge sharing in the silicon sensor. Photons down to 6 keV can be detected after equalization of the thresholds of individual pixels. The obtained results demonstrate the advantages of photon-counting hybrid pixel detectors and particularly of the Medipix-1 chip for a wide range of X-ray imaging applications, including those using synchrotron X-ray beams.

  8. Evaluation of 320x240 pixel LEC GaAs Schottky barrier X-ray imaging arrays, hybridized to CMOS readout circuit based on charge integration

    CERN Document Server

    Irsigler, R; Alverbro, J; Borglind, J; Froejdh, C; Helander, P; Manolopoulos, S; O'Shea, V; Smith, K

    1999-01-01

    320x240 pixels GaAs Schottky barrier detector arrays were fabricated, hybridized to silicon readout circuits, and subsequently evaluated. The detector chip was based on semi-insulating LEC GaAs material. The square shaped pixel detector elements were of the Schottky barrier type and had a pitch of 38 mu m. The GaAs wafers were thinned down prior to the fabrication of the ohmic back contact. After dicing, the chips were indium bump, flip-chip bonded to CMOS readout circuits based on charge integration, and finally evaluated. A bias voltage between 50 and 100 V was sufficient to operate the detector. Results on I-V characteristics, noise behaviour and response to X-ray radiation are presented. Images of various objects and slit patterns were acquired by using a standard dental imaging X-ray source. The work done was a part of the XIMAGE project financed by the European Community (Brite-Euram). (author)

  9. Continuous-wave and actively Q-switched Nd:LSO crystal lasers

    Science.gov (United States)

    Zhuang, S.; Li, D.; Xu, X.; Wang, Z.; Yu, H.; Xu, J.; Chen, L.; Zhao, Y.; Guo, L.; Xu, X.

    2012-04-01

    With a fiber coupled laser diode array as the pump source, Nd-doped Lu2SiO5 (Nd:LSO) crystal lasers at 4F3/2→4I11/2 and 4F3/2→4I13/2 transitions were demonstrated. The active Q-switched dual-wavelength lasers at about 1.08 μm, as well as continuous-wave (CW) and active Q-switched lasers at 1357 nm are reported for the first time, to the best of our knowledge. Considering the small emission cross-sections and long fluorescence lifetime, this material possesses large energy storage ability and excellent Q-switched properties. The special emission wavelength at 1357 nm will have promising applications to be used in many fields, such as THz generation, pumping of Cr3+:LiSAF, repumping of strontium optical clock, laser Doppler velocimeter and distributed fiber sensor.

  10. Evaluation of a photon-counting hybrid pixel detector array with a synchrotron X-ray source

    CERN Document Server

    Ponchut, C; Fornaini, A; Graafsma, H; Maiorino, M; Mettivier, G; Calvet, D

    2002-01-01

    A photon-counting hybrid pixel detector (Medipix-1) has been characterized using a synchrotron X-ray source. The detector consists of a readout ASIC with 64x64 independent photon-counting cells of 170x170 mu m sup 2 pitch, bump-bonded to a 300 mu m thick silicon sensor, read out by a PCIbus-based electronics, and a graphical user interface (GUI) software. The intensity and the energy tunability of the X-ray source allow characterization of the detector in the time, space, and energy domains. The system can be read out on external trigger at a frame rate of 100 Hz with 3 ms exposure time per frame. The detector response is tested up to more than 7x10 sup 5 detected events/pixel/s. The point-spread response shows <2% crosstalk between neighboring pixels. Fine scanning of the detector surface with a 10 mu m beam reveals no loss in sensitivity between adjacent pixels as could result from charge sharing in the silicon sensor. Photons down to 6 keV can be detected after equalization of the thresholds of individu...

  11. Lutetium oxyorthosilicate (LSO) intrinsic activity correction and minimal detectable target activity study for SPECT imaging with a LSO-based animal PET scanner

    Science.gov (United States)

    Yao, Rutao; Ma, Tianyu; Shao, Yiping

    2008-08-01

    This work is part of a feasibility study to develop SPECT imaging capability on a lutetium oxyorthosilicate (LSO) based animal PET system. The SPECT acquisition was enabled by inserting a collimator assembly inside the detector ring and acquiring data in singles mode. The same LSO detectors were used for both PET and SPECT imaging. The intrinsic radioactivity of 176Lu in the LSO crystals, however, contaminates the SPECT data, and can generate image artifacts and introduce quantification error. The objectives of this study were to evaluate the effectiveness of a LSO background subtraction method, and to estimate the minimal detectable target activity (MDTA) of image object for SPECT imaging. For LSO background correction, the LSO contribution in an image study was estimated based on a pre-measured long LSO background scan and subtracted prior to the image reconstruction. The MDTA was estimated in two ways. The empirical MDTA (eMDTA) was estimated from screening the tomographic images at different activity levels. The calculated MDTA (cMDTA) was estimated from using a formula based on applying a modified Currie equation on an average projection dataset. Two simulated and two experimental phantoms with different object activity distributions and levels were used in this study. The results showed that LSO background adds concentric ring artifacts to the reconstructed image, and the simple subtraction method can effectively remove these artifacts—the effect of the correction was more visible when the object activity level was near or above the eMDTA. For the four phantoms studied, the cMDTA was consistently about five times of the corresponding eMDTA. In summary, we implemented a simple LSO background subtraction method and demonstrated its effectiveness. The projection-based calculation formula yielded MDTA results that closely correlate with that obtained empirically and may have predicative value for imaging applications.

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

    Science.gov (United States)

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

    2016-07-01

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

  13. Polarisation measurements with a CdTe pixel array detector for Laue hard X-ray focusing telescopes

    CERN Document Server

    Caroli, E; Pisa, A; Stephen, J B; Frontera, F; Castanheira, M T D; Sordo, S; Caroli, Ezio; Silva, Rui M. Curado da; Pisa, Alessandro; Stephen, John B.; Frontera, Filippo; Castanheira, Matilde T. D.; Sordo, Stefano del

    2006-01-01

    Polarimetry is an area of high energy astrophysics which is still relatively unexplored, even though it is recognized that this type of measurement could drastically increase our knowledge of the physics and geometry of high energy sources. For this reason, in the context of the design of a Gamma-Ray Imager based on new hard-X and soft gamma ray focusing optics for the next ESA Cosmic Vision call for proposals (Cosmic Vision 2015-2025), it is important that this capability should be implemented in the principal on-board instrumentation. For the particular case of wide band-pass Laue optics we propose a focal plane based on a thick pixelated CdTe detector operating with high efficiency between 60-600 keV. The high segmentation of this type of detector (1-2 mm pixel size) and the good energy resolution (a few keV FWHM at 500 keV) will allow high sensitivity polarisation measurements (a few % for a 10 mCrab source in 106s) to be performed. We have evaluated the modulation Q factors and minimum detectable polaris...

  14. A novel gamma-ray detector with submillimeter resolutions using a monolithic MPPC array with pixelized Ce:LYSO and Ce:GGAG crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kato, T., E-mail: katou.frme.8180@asagi.waseda.jp [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Kataoka, J.; Nakamori, T.; Miura, T.; Matsuda, H.; Kishimoto, A. [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Sato, K.; Ishikawa, Y.; Yamamura, K.; Nakamura, S.; Kawabata, N. [Solid State Division, Hamamatsu Photonics K. K., 1126-1, Ichino-cho, Hamamatsu, Shizuoka (Japan); Ikeda, H. [ISAS/JAXA, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa (Japan); Yamamoto, S. [Kobe City College of Technology, 8-3, Gakuenhigashimati, Nishi-ku, Kobe-shi, Hyougo 651-2194 (Japan); Kamada, K. [Materials Research Laboratory, Furukawa Co., Ltd., 1-25-13, Kannondai, Tsukuba, Ibaraki 305-0856 (Japan)

    2013-01-21

    We have developed a large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of 4×4 channels with a three-side buttable package. Each channel has a photosensitive area of 3×3 mm{sup 2} and 3600 Geiger mode avalanche photodiodes (APDs). For typical operational gain of 7.5×10{sup 5} at +20 °C, gain fluctuation over the entire MPPC device is only ±5.6%, and dark count rates (as measured at the 1 p.e. level) amount to ≤400kcps per channel. We first fabricated a gamma-ray camera consisting of the MPPC array with one-to-one coupling to a Ce-doped (Lu,Y){sub 2}(SiO{sub 4})O (Ce:LYSO) crystal array (4×4 array of 3×3×10 mm{sup 3} crystals). Energy and time resolutions of 11.5±0.5% (FWHM at 662 keV) and 493±22ps were obtained, respectively. When using the charge division resistor network, which compiles signals into four position-encoded analog outputs, the ultimate positional resolution is estimated as 0.19 mm in both X and Y directions, while energy resolution of 10.2±0.4% (FWHM) was obtained. Finally, we fabricated submillimeter Ce:LYSO and Ce-doped Gd{sub 3}Ga{sub 3}Al{sub 2}O{sub 12} (Ce:GGAG) scintillator matrices each consisting of 1.0×1.0, 0.7×0.7 and 0.5×0.5 mm{sup 2} pixels, to further improve the spatial resolution. In all types of Ce:LYSO and Ce:GGAG matrices, each crystal was clearly resolved in the position histograms when irradiated by a {sup 137}Cs source. The energy resolutions for 662 keV gamma-rays for each Ce:LYSO and Ce:GGAG scintillator matrix were ≤14.3%. These results suggest excellent potential for its use as a high spatial medical imaging device, particularly in positron emission tomography (PET). -- Highlights: ► We developed a newly designed large-area monolithic MPPC array. ► We obtained fine gain uniformity, and good energy and time resolutions when coupled to the LYSO scintillator. ► We fabricated gamma-ray camera consisting of the MPPC array and submillimeter pixelized LYSO and GGAG scintillators. ► In

  15. The late-annotated small ORF LSO1 is a target gene of the iron regulon of Saccharomyces cerevisiae.

    Science.gov (United States)

    An, Xiuxiang; Zhang, Caiguo; Sclafani, Robert A; Seligman, Paul; Huang, Mingxia

    2015-12-01

    We have identified a new downstream target gene of the Aft1/2-regulated iron regulon in budding yeast Saccharomyces cerevisiae, the late-annotated small open reading frame LSO1. LSO1 transcript is among the most highly induced from a transcriptome analysis of a fet3-1 mutant grown in the presence of the iron chelator bathophenanthrolinedisulfonic acid. LSO1 has a paralog, LSO2, which is constitutively expressed and not affected by iron availability. In contrast, we find that the LSO1 promoter region contains three consensus binding sites for the Aft1/2 transcription factors and that an LSO1-lacZ reporter is highly induced under low-iron conditions in a Aft1-dependent manner. The expression patterns of the Lso1 and Lso2 proteins mirror those of their mRNAs. Both proteins are localized to the nucleus and cytoplasm, but become more cytoplasmic upon iron deprivation consistent with a role in iron transport. LSO1 and LSO2 appear to play overlapping roles in the cellular response to iron starvation since single lso1 and lso2 mutants are sensitive to iron deprivation and this sensitivity is exacerbated when both genes are deleted.

  16. Development of an Ultrahigh Resolution Block Detector Based on 0.4 mm Pixel Ce:GAGG Scintillators and a Silicon Photomultiplier Array

    Science.gov (United States)

    Yamamoto, Seiichi; Yeom, Jung Yeol; Kamada, Kei; Endo, Takanori; Levin, Craig S.

    2013-12-01

    Ce doped Gd3Al2Ga3O12 (Ce:GAGG) is a newly developed single-crystal scintillator which has a large light output and longer emission light wavelength. The longer wavelength of the scintillation photons will produce a larger signal when coupled to typical silicon photomultiplier (Si-PM) as the quantum efficiency of semiconductor based photodetector is generally higher for light with longer wavelength. A block detector with higher spatial resolution may thus be realized by combining Ce:GAGG with Si-PM arrays. To achieve the highest possible spatial resolution for PET and SPECT detectors, we developed an ultrahigh resolution block detector using 0.4 mm × 0.4 mm × 5 mm Ce:GAGG pixels assembled to form a 24 × 24 matrix that is coupled to an Si-PM array and evaluated the performance. All Ce:GAGG pixels were separated in the 2-dimensional position histograms for Cs-137 (662 keV) gamma photons with an average peak-to-valley (P/V) ratio of 2.4. The energy resolution was 21.6% FWHM for Cs-137 (662 keV) and 23.8% for Co-57 (122 keV) gamma photons. Since Ce:GAGG does not contain naturally occurring radioisotope (Lu), beta-gamma true coincidences can be avoided and randoms are reduced when used for PET detectors. Furthermore, this property, together with its high light output and good intrinsic energy resolution, make the scintillator suited for SPECT detectors. An ultrahigh resolution PET/SPECT hybrid system might be an interesting application using Ce:GAGG/Si-PM block detectors.

  17. A novel gamma-ray detector with submillimeter resolutions using a monolithic MPPC array with pixelized Ce:LYSO and Ce:GGAG crystals

    Science.gov (United States)

    Kato, T.; Kataoka, J.; Nakamori, T.; Miura, T.; Matsuda, H.; Kishimoto, A.; Sato, K.; Ishikawa, Y.; Yamamura, K.; Nakamura, S.; Kawabata, N.; Ikeda, H.; Yamamoto, S.; Kamada, K.

    2013-01-01

    We have developed a large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of 4×4 channels with a three-side buttable package. Each channel has a photosensitive area of 3×3 mm2 and 3600 Geiger mode avalanche photodiodes (APDs). For typical operational gain of 7.5×105 at +20 °C, gain fluctuation over the entire MPPC device is only ±5.6%, and dark count rates (as measured at the 1 p.e. level) amount to ≤400 kcps per channel. We first fabricated a gamma-ray camera consisting of the MPPC array with one-to-one coupling to a Ce-doped (Lu, Y)2(SiO4)O (Ce:LYSO) crystal array (4×4 array of 3×3×10 mm3 crystals). Energy and time resolutions of 11.5±0.5% (FWHM at 662 keV) and 493±22 ps were obtained, respectively. When using the charge division resistor network, which compiles signals into four position-encoded analog outputs, the ultimate positional resolution is estimated as 0.19 mm in both X and Y directions, while energy resolution of 10.2±0.4% (FWHM) was obtained. Finally, we fabricated submillimeter Ce:LYSO and Ce-doped Gd3Ga3Al2O12 (Ce:GGAG) scintillator matrices each consisting of 1.0×1.0, 0.7×0.7 and 0.5×0.5 mm2 pixels, to further improve the spatial resolution. In all types of Ce:LYSO and Ce:GGAG matrices, each crystal was clearly resolved in the position histograms when irradiated by a 137Cs source. The energy resolutions for 662 keV gamma-rays for each Ce:LYSO and Ce:GGAG scintillator matrix were ≤14.3%. These results suggest excellent potential for its use as a high spatial medical imaging device, particularly in positron emission tomography (PET).

  18. Effect of Pixel's Spatial Characteristics on Recognition of Isolated Pixelized Chinese Character.

    Science.gov (United States)

    Yang, Kun; Liu, Shuang; Wang, Hong; Liu, Wei; Wu, Yaowei

    2015-01-01

    The influence of pixel's spatial characteristics on recognition of isolated Chinese character was investigated using simulated prosthestic vision. The accuracy of Chinese character recognition with 4 kinds of pixel number (6*6, 8*8, 10*10, and 12*12 pixel array) and 3 kinds of pixel shape (Square, Dot and Gaussian) and different pixel spacing were tested through head-mounted display (HMD). A captured image of Chinese characters in font style of Hei were pixelized with Square, Dot and Gaussian pixel. Results showed that pixel number was the most important factor which could affect the recognition of isolated pixelized Chinese Chartars and the accuracy of recognition increased with the addition of pixel number. 10*10 pixel array could provide enough information for people to recognize an isolated Chinese character. At low resolution (6*6 and 8*8 pixel array), there were little difference of recognition accuracy between different pixel shape and different pixel spacing. While as for high resolution (10*10 and 12*12 pixel array), the fluctuation of pixel shape and pixel spacing could not affect the performance of recognition of isolated pixelized Chinese Character.

  19. Pixel Experiments

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Søndergaard, Karin; Augustesen, Christina

    2015-01-01

    Pixel Experiments The term pixel is traditionally defined as any of the minute elements that together constitute a larger context or image. A pixel has its own form and is the smallest unit seen within a larger structure. In working with the potentials of LED technology in architectural lighting...... design it became relevant to investigate the use of LEDs as the physical equivalent of a pixel as a design approach. In this book our interest has been in identifying how the qualities of LEDs can be used in lighting applications. With experiences in the planning and implementation of architectural...... elucidate and exemplify already well-known problems in relation to the experience of vertical and horizontal lighting. Pixel Experiments exist as a synergy between speculative test setups and lighting design in practice. This book is one of four books that is published in connection with the research...

  20. Calibratie 1994 van de gammaspectrometrie-opstellingen van LSO voor alarmsituaties en regulier onderzoek

    NARCIS (Netherlands)

    Verkerk EC; Tijsmans MH; Pennders RMJ; Tax RB; Reinen HAJM; LSO

    1995-01-01

    Om de activiteit van preparaten met gammastraling uitzendende nucliden te bepalen heeft het Laboratorium voor Stralingsonderzoek (LSO) de beschikking over een aantal halfgeleiderdetectoren. Deze opstellingen worden per preparaatvorm gekalibreerd voor de efficintie waarmee gemeten wordt. Dit rapp

  1. Pixel Detectors

    OpenAIRE

    Wermes, Norbert

    2005-01-01

    Pixel detectors for precise particle tracking in high energy physics have been developed to a level of maturity during the past decade. Three of the LHC detectors will use vertex detectors close to the interaction point based on the hybrid pixel technology which can be considered the state of the art in this field of instrumentation. A development period of almost 10 years has resulted in pixel detector modules which can stand the extreme rate and timing requirements as well as the very harsh...

  2. Note: application of a pixel-array area detector to simultaneous single crystal X-ray diffraction and X-ray absorption spectroscopy measurements.

    Science.gov (United States)

    Sun, Cheng-Jun; Zhang, Bangmin; Brewe, Dale L; Chen, Jing-Sheng; Chow, G M; Venkatesan, T; Heald, Steve M

    2014-04-01

    X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are two main x-ray techniques in synchrotron radiation facilities. In this Note, we present an experimental setup capable of performing simultaneous XRD and XAS measurements by the application of a pixel-array area detector. For XRD, the momentum transfer in specular diffraction was measured by scanning the X-ray energy with fixed incoming and outgoing x-ray angles. By selecting a small fixed region of the detector to collect the XRD signal, the rest of the area was available for collecting the x-ray fluorescence for XAS measurements. The simultaneous measurement of XRD and X-ray absorption near edge structure for Pr0.67Sr0.33MnO3 film was demonstrated as a proof of principle for future time-resolved pump-probe measurements. A static sample makes it easy to maintain an accurate overlap of the X-ray spot and laser pump beam.

  3. Evaluation of the multi-pixel photon counters with inorganic scintillators

    Science.gov (United States)

    Hitomi, Keitaro; Sato, Eiichi; Nomiya, Seiichiro; Shoji, Tadayoshi

    2007-09-01

    Multi-Pixel Photon Counter (MPPC) is a Hamamatsu's new Si avalanche photodiode. The main features of the MPPC are very high gain (10 5 to10 6) and very fast operation. The MPPC offers considerable advantages over widely used photomultiplier tubes (PMT) for scintillation detection, especially due to their high quantum efficiency, low cost, compactness, low operating voltage, mechanical robustness and insensitivity to magnetic fields. One of the most attractive applications of MPPCs is positron emission tomography (PET). In the present study, the MPPCs were coupled to inorganic scintillators including LSO, BGO and YAP in order to evaluate the scintillator/MPPC devices in terms of energy and timing resolutions for PET applications. The scintillation detector consisted of an LSO scintillator (2 mm × 2 mm × 4 mm) coupled to an MPPC exhibited energy resolutions of 196 keV FWHM and 189 keV FWHM for 511 keV and 662 keV gamma-rays, respectively. The MPPC was operated at a bias of 71.4 V and at room temperature. In order to investigate timing properties of the LSO/MPPC device, coincidence timing spectra between a reference scintillation detector which consisted of a BaF II crystal coupled to a PMT and the LSO/MPPC device were measured with 511 keV positron annihilation gamma-rays from a 22Na source. A coincidence timing resolution of 3.2 ns FWHM was obtained with the LSO/MPPC system.

  4. Evaluation of Matrix9 silicon photomultiplier array for small-animal PET

    Science.gov (United States)

    Du, Junwei; Schmall, Jeffrey P.; Yang, Yongfeng; Di, Kun; Roncali, Emilie; Mitchell, Gregory S.; Buckley, Steve; Jackson, Carl; Cherry, Simon R.

    2015-01-01

    Purpose: The MatrixSL-9-30035-OEM (Matrix9) from SensL is a large-area silicon photomultiplier (SiPM) photodetector module consisting of a 3 × 3 array of 4 × 4 element SiPM arrays (total of 144 SiPM pixels) and incorporates SensL’s front-end electronics board and coincidence board. Each SiPM pixel measures 3.16 × 3.16 mm2 and the total size of the detector head is 47.8 × 46.3 mm2. Using 8 × 8 polished LSO/LYSO arrays (pitch 1.5 mm) the performance of this detector system (SiPM array and readout electronics) was evaluated with a view for its eventual use in small-animal positron emission tomography (PET). Methods: Measurements of noise, signal, signal-to-noise ratio, energy resolution, flood histogram quality, timing resolution, and array trigger error were obtained at different bias voltages (28.0–32.5 V in 0.5 V intervals) and at different temperatures (5 °C–25 °C in 5 °C degree steps) to find the optimal operating conditions. Results: The best measured signal-to-noise ratio and flood histogram quality for 511 keV gamma photons were obtained at a bias voltage of 30.0 V and a temperature of 5 °C. The energy resolution and timing resolution under these conditions were 14.2% ± 0.1% and 4.2 ± 0.1 ns, respectively. The flood histograms show that all the crystals in the 1.5 mm pitch LSO array can be clearly identified and that smaller crystal pitches can also be resolved. Flood histogram quality was also calculated using different center of gravity based positioning algorithms. Improved and more robust results were achieved using the local 9 pixels for positioning along with an energy offset calibration. To evaluate the front-end detector readout, and multiplexing efficiency, an array trigger error metric is introduced and measured at different lower energy thresholds. Using a lower energy threshold greater than 150 keV effectively eliminates any mispositioning between SiPM arrays. Conclusions: In summary, the Matrix9 detector system can resolve

  5. Fast-channel LSO detectors and fiber-optic encoding for excellent dual photon transmission measurements in PET

    Energy Technology Data Exchange (ETDEWEB)

    Jones, W.F.; Moyers, J.C.; Casey, M.E.; Watson, C.C.; Nutt, R. [CTI PET Systems, Inc., Knoxville, TN (United States)

    1999-08-01

    Improved attenuation correction remains critical to PET. Currently with dual photon rotating rod sources, benefits of windowing are limited by counting losses of detectors nearest the rods, the near detectors. With single photon sources, improved statistics are offset by a greater need for collimation and more complex emission background correction. Now, a dual photon point source array with fast-channel, near detectors improves on these earlier techniques -- here, adding transmission measurement to dual-head rotating PET. Arrays of collimated point sources are aligned axially and orbit the FOV. With each source is a dedicated near detector (LSO crystal). Crystals couple to photomultipliers (PMTs). As the crystals are not ``block`` encoded, pulse-processing time is reduced (to 120 ns). Reduced processing time lowers dead time and permits hotter sources. For improved axial sampling, larger arrays (21 sources/head) may be configured. To reduce costs, crystals couple fiber-optically into unique PMT pairs -- decreasing the total number of near-detector PMTs by 71%.

  6. Pixel detectors

    CERN Document Server

    Passmore, M S

    2001-01-01

    positions on the detector. The loss of secondary electrons follows the profile of the detector and increases with higher energy ions. studies of the spatial resolution predict a value of 5.3 lp/mm. The image noise in photon counting systems is investigated theoretically and experimentally and is shown to be given by Poisson statistics. The rate capability of the LAD1 was measured to be 250 kHz per pixel. Theoretical and experimental studies of the difference in contrast for ideal charge integrating and photon counting imaging systems were carried out. It is shown that the contrast differs and that for the conventional definition (contrast = (background - signal)/background) the photon counting device will, in some cases, always give a better contrast than the integrating system. Simulations in MEDICI are combined with analytical calculations to investigate charge collection efficiencies (CCE) in semiconductor detectors. Different pixel sizes and biasing conditions are considered. The results show charge shari...

  7. Optimization of LSO/LuYAP phoswich detector for small animal PET

    Science.gov (United States)

    Jung, Jin Ho; Choi, Yong; Chung, Yong Hyun; Devroede, Olivier; Krieguer, Magalie; Bruyndonckx, Peter; Tavernier, Stefaan

    2007-02-01

    LSO/LuYAP phoswich detectors for small animal PET were developed to measure the depth of interaction (DOI), and to improve the spatial resolution at the edge of the field of view (FOV). The aim of this study was to optimize the optical coupling conditions between the crystal and photomultiplier tube (PMT) to maximize the light-collection efficiency, and to develop a method for rejecting scatter events by applying an equal energy window in each crystal layer. The light yields of the phoswich detector were estimated by changing the refractive index of the optical coupling material using a DETECT simulation. The accuracy of the DOI measurement on the phoswich detector, using an optical coupling material with the optimal light yield, were evaluated experimentally and compared with the air condition. The energy window for the photopeak events cannot be applied properly because the light outputs of LSO and LuYAP are different. The LSO/LuYAP photopeaks need to be superposed in order to effectively discriminate the scattered events by applying an equal energy window. The photopeaks of the LSO and LuYAP can be superposed by inserting a reflecting material between the crystals. The optimal coverage ratio of the inserting material was derived from a DETECT simulation, and its performance was investigated. In the simulation result, optimal refractive index of the optical coupling material was 1.7. The average DOI measurement errors of the LSO/LuYAP were 0.6%/3.4% and 4.9%/41.4% in the phoswich detector with and without an optical coupling material, respectively. The photopeaks of the LSO and LuYAP were superposed by covering 75% of the contact surface between the crystals with white Teflon. The DOI measurement errors of the LSO/LuYAP were 0.2%/2.4%. In this study, the optimal condition of the optical coupling material inserted between the crystal and PMT was derived to improve the accuracy of DOI measurement, and a photopeak superposition method of the LSO and LuYAP was

  8. Bump bonding of pixel systems

    Energy Technology Data Exchange (ETDEWEB)

    Lozano, M. E-mail: manuel.lozano@cnm.es; Cabruja, E.; Collado, A.; Santander, J.; Ullan, M

    2001-11-01

    A pixel detector consists of an array of radiation sensing elements which is connected to an electronic read-out unit. Many different ways of making this connection between these two different devices are currently being used or considered to be used in the next future. Bonding techniques such as flip chip technology can present real advantages because they allow very fine pitch and a high number of I/Os. This paper presents a review of the different flip chip technologies available and their suitability for manufacturing pixel detectors. The particular problems concerning testing of pixel detectors and thermal issues related to them are pointed out.

  9. Bump bonding of pixel systems

    CERN Document Server

    Lozano, M; Collado, A; Santander, J; Ullán, M

    2001-01-01

    A pixel detector consists of an array of radiation sensing elements which is connected to an electronic read-out unit. Many different ways of making this connection between these two different devices are currently being used or considered to be used in the next future. Bonding techniques such as flip chip technology can present real advantages because they allow very fine pitch and a high number of I/Os. This paper presents a review of the different flip chip technologies available and their suitability for manufacturing pixel detectors. The particular problems concerning testing of pixel detectors and thermal issues related to them are pointed out.

  10. Noise Analysis of Array Pixellated CZT Detector%CZT像素阵列核探测器的噪声分析

    Institute of Scientific and Technical Information of China (English)

    蒋建; 肖沙里; 蔡欣; 张流强; 陈宇晓; 曹玉琳

    2011-01-01

    碲锌镉(CdZnTe)晶体是一种新型核辐射探测材料,在室温探测环境下对X射线及低能量伽玛射线具有较高的探测效率及能量分辨率.运用低噪声快速前放模块,分析晶体内部性能以及前置放大器对探测系统噪声的影响,建立了2×2碲锌镉像素阵列探测系统.实验结果表明,探测系统输出信号噪声小、脉冲无堆积,读出电路电子学噪声得到明显抑制,能谱低能拖尾减少,电荷收集不完全噪声及漏电流噪声影响得到改善,同时对整个系统以及前置放大器进行了噪声分析并提出相关的改善方式,最后得到系统测试的结果.%As a novel nuclear radiation material, CdZnTe has many advantages of high effi ciency detection and good energy resolution for detection of x-ray and low energy gamma-ray in room temperature. The inner crystal property and effects of preamplifier on the noise is analyzed using low noise preamplifier module, while a 2× 2 array pixellated detection system is built. The results show a low noise of output signal and no pulse stack. The circuit electronic noise is obvi ously restrained. Trails of low power of energy spectrum are decreased. Noise analysis and the factors which produced the noise are given; improvement for the system is also discussed, togeth er with the test result.

  11. Dead pixel replacement in LWIR microgrid polarimeters.

    Science.gov (United States)

    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.

  12. Pixel Design of Organic Thin Film Transistor Array%有机薄膜晶体管阵列面向电子纸像素设计

    Institute of Scientific and Technical Information of China (English)

    汪梅林; 张其国; 郑永亮; 秦永亮; 郭晓东; 潭莉; 朱棋锋; 韩学斌; 申剑锋

    2012-01-01

    As a switch device of the pixel, the Organic Thin Film Transistor(OTFT) has good IDS-VGS curve. This paper describes the pixel circuit, model parameter for HSPICE simulation and the pixel layout. In order to verify the influence of storage capacitor and TFT structure on the pixel waveform, the pixel waveform was simulated by HSPICE. The OTFT process is studied in this paper. Result shows that OTFT structure is selected according to the storage capacitor for different products. The OTFT process is suitable for flexible display.%讨论了有机薄膜晶体管(Organic Thin Film Transistor,OTFT)作为开关器件来驱动电子纸的像素设计,特别是像素电路结构、HSPICE模拟用模型参数和像素平面结构.讨论了有机薄膜晶体管制造过程,并用HSPIC模拟分析了有机薄膜晶体管结构和存贮电容大小对像素波形的影响,结果表明TFT结构的选择依赖于存贮电容的大小.

  13. Characterization of 176Lu background in LSO-based PET scanners

    Science.gov (United States)

    Conti, Maurizio; Eriksson, Lars; Rothfuss, Harold; Sjoeholm, Therese; Townsend, David; Rosenqvist, Göran; Carlier, Thomas

    2017-05-01

    LSO and LYSO are today the most common scintillators used in positron emission tomography. Lutetium contains traces of 176Lu, a radioactive isotope that decays β - with a cascade of γ photons in coincidence. Therefore, Lutetium-based scintillators are characterized by a small natural radiation background. In this paper, we investigate and characterize the 176Lu radiation background via experiments performed on LSO-based PET scanners. LSO background was measured at different energy windows and different time coincidence windows, and by using shields to alter the original spectrum. The effect of radiation background in particularly count-starved applications, such as 90Y imaging, is analysed and discussed. Depending on the size of the PET scanner, between 500 and 1000 total random counts per second and between 3 and 5 total true coincidences per second were measured in standard coincidence mode. The LSO background counts in a Siemens mCT in the standard PET energy and time windows are in general negligible in terms of trues, and are comparable to that measured in a BGO scanner of similar size.

  14. Comparison of LSO and BGO block detectors for prompt gamma imaging in ion beam therapy

    Science.gov (United States)

    Hueso-González, F.; Biegun, A. K.; Dendooven, P.; Enghardt, W.; Fiedler, F.; Golnik, C.; Heidel, K.; Kormoll, T.; Petzoldt, J.; Römer, K. E.; Schwengner, R.; Wagner, A.; Pausch, G.

    2015-09-01

    A major weakness of ion beam therapy is the lack of tools for verifying the particle range in clinical routine. The application of the Compton camera concept for the imaging of prompt gamma rays, a by-product of the irradiation correlated to the dose distribution, is a promising approach for range assessment and even three-dimensional in vivo dosimetry. Multiple position sensitive gamma ray detectors arranged in scatter and absorber planes, together with an imaging algorithm, are required to reconstruct the prompt gamma emission density map. Conventional block detectors deployed in Positron Emission Tomography (PET), which are based on Lu2SiO5:Ce (LSO) and Bi4Ge3O12 (BGO) scintillators, are suitable candidates for the absorber of a Compton camera due to their high density and absorption efficiency with respect to the prompt gamma energy range (several MeV). We compare experimentally LSO and BGO block detectors in clinical-like radiation fields in terms of energy, spatial and time resolution. The high energy range compensates for the low light yield of the BGO material and boosts significantly its performance compared to the PET scenario. Notwithstanding the overall superiority of LSO, BGO catches up in the field of prompt gamma imaging and can be considered as a competitive alternative to LSO for the absorber plane due to its lower price and the lack of intrinsic radioactivity.

  15. Measurement results of a 12 μm pixel size microbolometer array based on a novel thermally isolating structure using a 17 μm ROIC

    Science.gov (United States)

    Muckensturm, K.-M.; Weiler, D.; Hochschulz, F.; Busch, C.; Geruschke, T.; Wall, S.; Heß, J.; Würfel, D.; Lerch, R.; Vogt, H.

    2016-05-01

    In this paper a novel concept for the fabrication of highly sensitive uncooled microbolometers is presented. The approach is based on the realization of thermal isolation and simultaneous electrical contacting of the microbolometers by means of sufficiently long and thin coated nanotubes, which can be fabricated by post processing on top of CMOS wafers comprising the ROIC. Thus, the effective area of the absorption layer is maximized at a given pixel size, as lateral legs, which have been the main component of the thermal isolation commonly, are completely omitted. The resulting thermal conductivity can be tuned independently from the pixel size by varying the geometry and structuring of the nanotubes. Based on test structures the nanotube microbolometers are characterized with respect to electro-optical and mechanical properties. The focus in this paper is on nanotube microbolometers with a pixel size of 12 μm.

  16. InAs/GaSb Type-II superlattice photodiode array inter-pixel region blue-shift by femtosecond (fs) laser anneal

    Science.gov (United States)

    Das, Sona; Das, Utpal

    2017-09-01

    A post-growth blue-shift in the band gap of an undoped InAs/GaSb Type-II superlattice (5.5 μm cutoff wavelength), as a result of 775 nm, 150 fs laser annealing, is presented. A band gap blue-shift of ∼72 meV in the {{{p}}}+- and p-layer etched inter-pixel region, laser annealed superlattice is achieved. Using an inter-diffusion model, the dominant group-III and group-V diffusion coefficients are found to be 1.33× {10}-21 {{{m}}}2 {{{s}}}-1 and 4.8× {10}-22 {{{m}}}2 {{{s}}}-1 respectively. Confirmation of the unaltered condition of the superlattice in a Ti/Au masked pixel area establishes this blue-shifted superlattice band gap to be the reason behind the improved inter-pixel isolation resulting from the fs laser annealing technique.

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

    Science.gov (United States)

    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.

  18. Ultrahigh Detective Heterogeneous Photosensor Arrays with In-Pixel Signal Boosting Capability for Large-Area and Skin-Compatible Electronics.

    Science.gov (United States)

    Kim, Jaehyun; Kim, Jaekyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Myungwon; Moon, Juhyuk; Yang, Lin; Kim, Myung-Gil; Kim, Yong-Hoon; Park, Sung Kyu

    2016-04-01

    An ultra-thin and large-area skin-compatible heterogeneous organic/metal-oxide photosensor array is demonstrated which is capable of sensing and boosting signals with high detectivity and signal-to-noise ratio. For the realization of ultra-flexible and high-sensitive heterogeneous photosensor arrays on a polyimide substrate having organic sensor arrays and metal-oxide boosting circuitry, solution-processing and room-temperature alternating photochemical conversion routes are applied. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Diode-pumped continuous wave tunable and graphene Q-switched Tm:LSO lasers.

    Science.gov (United States)

    Feng, T L; Zhao, S Z; Yang, K J; Li, G Q; Li, D C; Zhao, J; Qiao, W C; Hou, J; Yang, Y; He, J L; Zheng, L H; Wang, Q G; Xu, X D; Su, L B; Xu, J

    2013-10-21

    We have investigated the lasing characteristics of Tm:LSO crystal in three operation regimes: continuous wave (CW), wavelength tunable and passive Q-switching based on graphene. In CW regime, a maximum output power of 0.65 W at 2054.9 nm with a slope efficiency of 21% was achieved. With a quartz plate, a broad wavelength tunable range of 145 nm was obtained, corresponding to a FWHM of 100 nm. By using a graphene saturable absorber mirror, the passively Q-switched Tm:LSO laser produced pulses with duration of 7.8 μs at 2030.8 nm under a repetition rate of 7.6 kHz, corresponding to pulse energy of 14.0 μJ.

  20. Comparison of LSO samples produced by Czochralsky and modified Musatov methods

    CERN Document Server

    Antich, P; Tsyganov, E N; Garmash, V; Zheleznykh, I

    2000-01-01

    This study is based on test results of 30 LSO samples produced by the POLUS Research Institute in Moscow, Russia, for the University of Texas Southwestern Medical Center at Dallas. Samples were produced by the Czochralsky and the modified Musatov methods. Pulse-height spectra from sup 2 sup 2 Na positron annihilations were analyzed and conclusions are drawn. After some minor corrections to the modified Musatov technology, samples could be recommended for use in PET systems.

  1. 11th International Workshop on Learning Software Organizations (LSO 2009) New Media in Transfer and Innovation

    Science.gov (United States)

    Jedlitschka, Andreas; Vegas, Sira

    Software is one of the most important drivers of innovation. As organizations are becoming more dependent on software, the improvement of software quality and productivity becomes of essential importance for the competitiveness of an organization. Continuing the success of the LSO Workshop series since 1999, this workshop will provide a communication forum bringing together academia and industry for discussing the advancements made and addressing the challenges faced by continuous learning in software-intensive organizations.

  2. A Linked Simulation-Optimization (LSO) Model for Conjunctive Irrigation Management using Clonal Selection Algorithm

    Science.gov (United States)

    Islam, Sirajul; Talukdar, Bipul

    2016-09-01

    A Linked Simulation-Optimization (LSO) model based on a Clonal Selection Algorithm (CSA) was formulated for application in conjunctive irrigation management. A series of measures were considered for reducing the computational burden associated with the LSO approach. Certain modifications were incurred to the formulated CSA, so as to decrease the number of function evaluations. In addition, a simple problem specific code for a two dimensional groundwater flow simulation model was developed. The flow model was further simplified by a novel approach of area reduction, in order to save computational time in simulation. The LSO model was applied in the irrigation command of the Pagladiya Dam Project in Assam, India. With a view to evaluate the performance of the CSA, a Genetic Algorithm (GA) was used as a comparison base. The results from the CSA compared well with those from the GA. In fact, the CSA was found to consume less computational time than the GA while converging to the optimal solution, due to the modifications incurred in it.

  3. Design of equivalent pixel circuit for infrared focal plane array%用于红外焦平面阵列的等效像元电路设计

    Institute of Scientific and Technical Information of China (English)

    戴山彪; 陈力颖; 邢海英; 王健; 杨晓龙

    2015-01-01

    An equivalent pixel circuit for 300 ×400 infrared focal plane array readout circuit structure is presented in this paper.The circuit′s electrical characteristics are equivalent to that of the vanadium oxide (VOx film)micro -mechanical systems (MEMS).It can simulate the variation of the branch current when the MEMS pixel changes.Be-fore the growth of physical structure of MEMS (VOx film),the infrared array detector readout circuit has been fabrica-ted.The equivalent pixel circuit is designed to test the electrical properties of the readout circuit.It can remove the defective products and reduce packaging costs.The circuit has been designed and fabricated with a GlobalFoundry 0.35 μm process.The test results indicate that the equivalent circuit has the same electrical properties as the MEMS pixel when the integrating current is 0 ~200 nA.%提出了一种用于300×400红外焦平面阵列读出电路的等效像元电路结构。该电路与氧化钒(VOx 薄膜)制成的微机械系统(MEMS)的电特性等效,并能够模拟 MEMS 像元改变时支路电流的变化。红外面阵探测器读出电路在流片后,生长 MEMS 物理结构(VOx 薄膜)前,该等效像元电路结构用于读出电路的电性能测试,从而剔除不良品,减少封装成本。该电路采用了 GlobalFoundry 0.35μm 工艺设计并流片。测试结果表明,当积分电流为0~200 nA 时,该等效像元电路的电性能与 MEMS 像元一致。

  4. Study of multi-pixel Geiger-mode avalanche photodiodes as a read-out for PET

    CERN Document Server

    Musienko, Yuri; Lecoq, Paul; Reucroft, Stephen; Swain, John; Trummer, Julia

    2007-01-01

    We have studied the performance of two multi-pixel Geiger-mode APDs (recently developed by the Centre of Perspective Technologies and Apparatus (CPTA) in Moscow) with 1×1 mm2 and 3×3 mm2 sensitive area as a readout for LSO and LYSO scintillator crystals. Energy and timing spectra were measured using a 22Na γ-source. The results of this study allow us to conclude that this photodetector is a very promising candidate for PET applications.

  5. Penrose Pixels for Super-Resolution.

    Science.gov (United States)

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

    2011-07-01

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

  6. Low-noise low-jitter 32-pixels CMOS single-photon avalanche diodes array for single-photon counting from 300 nm to 900 nm

    Energy Technology Data Exchange (ETDEWEB)

    Scarcella, Carmelo; Tosi, Alberto, E-mail: alberto.tosi@polimi.it; Villa, Federica; Tisa, Simone; Zappa, Franco [Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy)

    2013-12-15

    We developed a single-photon counting multichannel detection system, based on a monolithic linear array of 32 CMOS SPADs (Complementary Metal-Oxide-Semiconductor Single-Photon Avalanche Diodes). All channels achieve a timing resolution of 100 ps (full-width at half maximum) and a photon detection efficiency of 50% at 400 nm. Dark count rate is very low even at room temperature, being about 125 counts/s for 50 μm active area diameter SPADs. Detection performance and microelectronic compactness of this CMOS SPAD array make it the best candidate for ultra-compact time-resolved spectrometers with single-photon sensitivity from 300 nm to 900 nm.

  7. Characterization of a mammographic system based on single photon counting pixel arrays coupled to GaAs x-ray detectors.

    Science.gov (United States)

    Amendolia, S R; Bisogni, M G; Delogu, P; Fantacci, M E; Paternoster, G; Rosso, V; Stefanini, A

    2009-04-01

    The authors report on the imaging capabilities of a mammographic system demonstrator based on GaAs pixel detectors operating in single photon counting (SPC) mode. The system imaging performances have been assessed by means of the transfer functions: The modulation transfer function (MTF), the normalized noise power spectrum, and the detective quantum efficiency (DQE) have been measured following the guidelines of the IEC 62220-1-2 protocol. The transfer function analysis has shown the high spatial resolution capabilities of the GaAs detectors. The MTF calculated at the Nyquist frequency (2.94 cycles/mm) is indeed 60%. The DQE, measured with a standard mammographic beam setup (Mo/Mo, 28 kVp, with 4 mm Al added filter) and calculated at zero frequency, is 46%. Aiming to further improve the system's image quality, the authors investigate the DQE limiting factors and show that they are mainly related to system engineering. For example, the authors show that optimization of the image equalization procedure increases the DQE(0) up to 74%, which is better than the DQE(0) of most clinical mammographic systems. The authors show how the high detection efficiency of GaAs detectors and the noise discrimination associated with the SPC technology allow optimizing the image quality in mammography. In conclusion, the authors propose technological solutions to exploit to the utmost the potentiality of GaAs detectors coupled to SPC electronics.

  8. Effect of Pixel’s Spatial Characteristics on Recognition of Isolated Pixelized Chinese Character

    Science.gov (United States)

    Yang, Kun; Liu, Shuang; Wang, Hong; Liu, Wei; Wu, Yaowei

    2015-01-01

    The influence of pixel’s spatial characteristics on recognition of isolated Chinese character was investigated using simulated prosthestic vision. The accuracy of Chinese character recognition with 4 kinds of pixel number (6*6, 8*8, 10*10, and 12*12 pixel array) and 3 kinds of pixel shape (Square, Dot and Gaussian) and different pixel spacing were tested through head-mounted display (HMD). A captured image of Chinese characters in font style of Hei were pixelized with Square, Dot and Gaussian pixel. Results showed that pixel number was the most important factor which could affect the recognition of isolated pixelized Chinese Chartars and the accuracy of recognition increased with the addition of pixel number. 10*10 pixel array could provide enough information for people to recognize an isolated Chinese character. At low resolution (6*6 and 8*8 pixel array), there were little difference of recognition accuracy between different pixel shape and different pixel spacing. While as for high resolution (10*10 and 12*12 pixel array), the fluctuation of pixel shape and pixel spacing could not affect the performance of recognition of isolated pixelized Chinese Character. PMID:26628934

  9. A neighbor pixel communication filtering structure for Dynamic Vision Sensors

    Science.gov (United States)

    Xu, Yuan; Liu, Shiqi; Lu, Hehui; Zhang, Zilong

    2017-02-01

    For Dynamic Vision Sensors (DVS), thermal noise and junction leakage current induced Background Activity (BA) is the major cause of the deterioration of images quality. Inspired by the smoothing filtering principle of horizontal cells in vertebrate retina, A DVS pixel with Neighbor Pixel Communication (NPC) filtering structure is proposed to solve this issue. The NPC structure is designed to judge the validity of pixel's activity through the communication between its 4 adjacent pixels. The pixel's outputs will be suppressed if its activities are determined not real. The proposed pixel's area is 23.76×24.71μm2 and only 3ns output latency is introduced. In order to validate the effectiveness of the structure, a 5×5 pixel array has been implemented in SMIC 0.13μm CIS process. 3 test cases of array's behavioral model show that the NPC-DVS have an ability of filtering the BA.

  10. Evaluation of Matrix9 silicon photomultiplier array for small-animal PET

    Energy Technology Data Exchange (ETDEWEB)

    Du, Junwei, E-mail: jwdu@ucdavis.edu; Schmall, Jeffrey P.; Yang, Yongfeng; Di, Kun; Roncali, Emilie; Mitchell, Gregory S. [Department of Biomedical Engineering, University of California-Davis, One Shields Avenue, Davis, California 95616 (United States); Buckley, Steve; Jackson, Carl [SensL Technologies Ltd., 6800 Airport Business Park, Cork (Ireland); Cherry, Simon R. [Department of Biomedical Engineering, University of California-Davis, One Shields Avenue, Davis, California, 95616 (United States)

    2015-02-15

    Purpose: The MatrixSL-9-30035-OEM (Matrix9) from SensL is a large-area silicon photomultiplier (SiPM) photodetector module consisting of a 3 × 3 array of 4 × 4 element SiPM arrays (total of 144 SiPM pixels) and incorporates SensL’s front-end electronics board and coincidence board. Each SiPM pixel measures 3.16 × 3.16 mm{sup 2} and the total size of the detector head is 47.8 × 46.3 mm{sup 2}. Using 8 × 8 polished LSO/LYSO arrays (pitch 1.5 mm) the performance of this detector system (SiPM array and readout electronics) was evaluated with a view for its eventual use in small-animal positron emission tomography (PET). Methods: Measurements of noise, signal, signal-to-noise ratio, energy resolution, flood histogram quality, timing resolution, and array trigger error were obtained at different bias voltages (28.0–32.5 V in 0.5 V intervals) and at different temperatures (5 °C–25 °C in 5 °C degree steps) to find the optimal operating conditions. Results: The best measured signal-to-noise ratio and flood histogram quality for 511 keV gamma photons were obtained at a bias voltage of 30.0 V and a temperature of 5 °C. The energy resolution and timing resolution under these conditions were 14.2% ± 0.1% and 4.2 ± 0.1 ns, respectively. The flood histograms show that all the crystals in the 1.5 mm pitch LSO array can be clearly identified and that smaller crystal pitches can also be resolved. Flood histogram quality was also calculated using different center of gravity based positioning algorithms. Improved and more robust results were achieved using the local 9 pixels for positioning along with an energy offset calibration. To evaluate the front-end detector readout, and multiplexing efficiency, an array trigger error metric is introduced and measured at different lower energy thresholds. Using a lower energy threshold greater than 150 keV effectively eliminates any mispositioning between SiPM arrays. Conclusions: In summary, the Matrix9 detector system

  11. ATLAS IBL Pixel Upgrade

    CERN Document Server

    La Rosa, A

    2011-01-01

    The upgrade for ATLAS detector will undergo different phase towards super-LHC. The first upgrade for the Pixel detector will consist of the construction of a new pixel layer which will be installed during the first shutdown of the LHC machine (LHC phase-I upgrade). The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of 3.3 cm. The IBL will require the development of several new technologies to cope with increase of radiation or pixel occupancy and also to improve the physics performance which will be achieved by reducing the pixel size and of the material budget. Three different promising sensor technologies (planar-Si, 3D-Si and diamond) are currently under investigation for the pixel detector. An overview of the project with particular emphasis on pixel module is presented in this paper

  12. A count-rate model for PET scanners using pixelated Anger-logic detectors with different scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Surti, S; Karp, J S [Department of Radiology, University of Pennsylvania, 110 Donner Building (HUP), 3400 Spruce Street, Philadelphia, PA 19104 (United States)

    2005-12-07

    A high count-rate simulation (HCRSim) model has been developed so that all results are derived from fundamental physics principles. Originally developed to study the behaviour of continuous sodium iodide (NaI(Tl)) detectors, this model is now applied to PET scanners based on pixelated Anger-logic detectors using lanthanum bromide (LaBr{sub 3}), gadolinium orthosilicate (GSO) and lutetium orthosilicate (LSO) scintillators. This simulation has been used to study the effect on scanner deadtime and pulse pileup at high activity levels due to the scintillator stopping power ({mu}), decay time ({tau}) and energy resolution. Simulations were performed for a uniform 20 cm diameter x 70 cm long cylinder (NEMA NU2-2001 standard) in a whole-body scanner with an 85 cm ring diameter and a 25 cm axial field-of-view. Our results for these whole-body scanners demonstrate the potential of a pixelated Anger-logic detector and the relationship of its performance with the scanner NEC rate. Faster signal decay and short coincidence timing window lead to a reduction in deadtime and randoms fraction in the LaBr{sub 3} and LSO scanners compared to GSO. The excellent energy resolution of LaBr{sub 3} leads to the lowest scatter fraction for all scanners and helps compensate for reduced sensitivity compared to the GSO and LSO scanners, leading to the highest NEC values at high activity concentrations. The LSO scanner has the highest sensitivity of all the scanner designs investigated here, therefore leading to the highest peak NEC value but at a lower activity concentration than that of LaBr{sub 3}.

  13. A count-rate model for PET scanners using pixelated Anger-logic detectors with different scintillators.

    Science.gov (United States)

    Surti, S; Karp, J S

    2005-12-07

    A high count-rate simulation (HCRSim) model has been developed so that all results are derived from fundamental physics principles. Originally developed to study the behaviour of continuous sodium iodide (NaI(Tl)) detectors, this model is now applied to PET scanners based on pixelated Anger-logic detectors using lanthanum bromide (LaBr(3)), gadolinium orthosilicate (GSO) and lutetium orthosilicate (LSO) scintillators. This simulation has been used to study the effect on scanner deadtime and pulse pileup at high activity levels due to the scintillator stopping power (mu), decay time (tau) and energy resolution. Simulations were performed for a uniform 20 cm diameter x 70 cm long cylinder (NEMA NU2-2001 standard) in a whole-body scanner with an 85 cm ring diameter and a 25 cm axial field-of-view. Our results for these whole-body scanners demonstrate the potential of a pixelated Anger-logic detector and the relationship of its performance with the scanner NEC rate. Faster signal decay and short coincidence timing window lead to a reduction in deadtime and randoms fraction in the LaBr(3) and LSO scanners compared to GSO. The excellent energy resolution of LaBr(3) leads to the lowest scatter fraction for all scanners and helps compensate for reduced sensitivity compared to the GSO and LSO scanners, leading to the highest NEC values at high activity concentrations. The LSO scanner has the highest sensitivity of all the scanner designs investigated here, therefore leading to the highest peak NEC value but at a lower activity concentration than that of LaBr(3).

  14. Pixel Vertex Detectors

    OpenAIRE

    Wermes, Norbert

    2006-01-01

    Pixel vertex detectors are THE instrument of choice for the tracking of charged particles close to the interaction point at the LHC. Hybrid pixel detectors, in which sensor and read-out IC are separate entities, constitute the present state of the art in detector technology. Three of the LHC detectors use vertex detectors based on this technology. A development period of almost 10 years has resulted in pixel detector modules which can stand the extreme rate and timing requirements as well as ...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2016-05-01

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

  17. Monolithic CMOS pixel detector for international linear collider vertex detection

    Indian Academy of Sciences (India)

    J E Brau; O Igonkina; N Sinew; D Strom; C Baltay; W Emmet; H Neal; D Rabinowitz

    2007-12-01

    A monolithic CMS pixel detector is under development for an ILC experiment. This chronopixel array provides a time stamp resolution of one bunch crossing, a critical feature for background suppression. The status of this effort is summarized.

  18. A positron emission tomograph based on LSO-APD modules with a sampling ADC read-out system for a students' advanced laboratory course.

    Science.gov (United States)

    Schneider, Florian R; Mann, Alexander B; Konorov, Igor; Delso, Gaspar; Paul, Stephan; Ziegler, Sibylle I

    2012-06-01

    A one-day laboratory course on positron emission tomography (PET) for the education of physics students and PhD students in medical physics has been set up. In the course, the physical background and the principles of a PET scanner are introduced. Course attendees set the system in operation, calibrate it using a (22)Na point source and reconstruct different source geometries filled with (18)F. The PET scanner features an individual channel read-out of 96 lutetium oxyorthosilicate (LSO) scintillator crystals coupled to avalanche photodiodes (APD). The analog data of each APD are digitized by fast sampling analog to digital converters (SADC) and processed within field programmable gate arrays (FPGA) to extract amplitudes and time stamps. All SADCs are continuously sampling with a precise rate of 80MHz, which is synchronous for the whole system. The data is transmitted via USB to a Linux PC, where further processing and the image reconstruction are performed. The course attendees get an insight into detector techniques, modern read-out electronics, data acquisition and PET image reconstruction. In addition, a short introduction to some common software applications used in particle and high energy physics is part of the course.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fahim Farah, Fahim Farah [Northwestern U. (main); Deptuch, Grzegorz W. [Fermilab; Hoff, James R. [Fermilab; Mohseni, Hooman [Northwestern U. (main)

    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.

  20. "Charlie,"development of a light-weight, virtual reality trainer for the LSO community: time to make the leap toward immersive VR

    OpenAIRE

    Greunke, Larry C.

    2015-01-01

    Approved for public release; distribution is unlimited Landing Signal Officers (LSOs) are the backbone of tailhook naval aviation. Currently, once a junior officer is selected from a squadron to become an LSO, that person typically will go through an entire workup cycle before going to the Initial Formal Ground Training (IFGT) course. This means that an LSO will undergo months of on-the-job training at sea and assume different roles needed to recover aircraft before that individual receive...

  1. Sub-100 ps coincidence time resolution for positron emission tomography with LSO:Ce codoped with Ca

    CERN Document Server

    Nemallapudi, Mythra Varun; Lecoq, Paul; Auffray, Etiennette; Ferri, Alessandro; Gola, Alberto; Piemonte, Claudio

    2015-01-01

    The coincidence time resolution (CTR) becomes a key parameter of 511keV gamma detection in time of flight positron emission tomography (TOF-PET). This is because additional information obtained through timing leads to a better noise suppression and therefore a better signal to noise ratio in the reconstructed image. In this paper we present the results of CTR measurements on two different SiPM technologies from FBK coupled to LSO:Ce codoped 0.4%Ca crystals. We compare the measurements performed at two separate test setups, i.e. at CERN and at FBK, showing that the obtained results agree within a few percent. We achieve a best CTR value of 85  ±  4 ps FWHM for 2  ×  2  ×  3 mm3 LSO:Ce codoped 0.4%Ca crystals, thus breaking the 100 ps barrier with scintillators similar to LSO:Ce or LYSO:Ce. We also demonstrate that a CTR of 140  ±  5 ps can be achieved for longer 2  ×  2  ×  20 mm3 crystals, which can readily be implemented in the current generation PET syst...

  2. The pixelated detector

    CERN Multimedia

    Sutton, C

    1990-01-01

    "Collecting data as patterns of light or subatomic particles is vitally important in all the sciences. The new generation of solid-state detectors called pixel devices could transform experimental research at all levels" (4 pages).

  3. Maturation of calcium-dependent GABA, glycine, and glutamate release in the glycinergic MNTB-LSO pathway.

    Directory of Open Access Journals (Sweden)

    Javier Alamilla

    Full Text Available The medial nucleus of the trapezoid body (MNTB is a key nucleus in high-fidelity temporal processing that underlies sound localization in the auditory brainstem. While the glycinergic principal cells of the MNTB project to all primary nuclei of the superior olive, during development the projection from MNTB to the lateral superior olive (LSO is of interest because this immature inhibitory projection is known to undergo tonotopic refinement during an early postnatal period, and because during this period individual MNTB terminals in the LSO transiently release glycine GABA and glutamate. Developmental changes in calcium-dependent release are understood to be required to allow various auditory nuclei to follow high frequency activity; however, little is known about maturation of calcium-dependent release in the MNTB-LSO pathway, which has been presumed to have less stringent requirements for high-fidelity temporal following. In acute brainstem slices of rats age postnatal day 1 to 15 we recorded whole-cell responses in LSO principal neurons to electrical stimulation in the MNTB in order to measure sensitivity to external calcium, the contribution of different voltage-gated calcium channel subtypes to vesicular release, and the maturation of these measures for both GABA/glycine and glutamate transmission. Our results establish that release of glutamate at MNTB-LSO synapses is calcium-dependent. Whereas no significant developmental changes were evident for glutamate release, GABA/glycine release underwent substantial changes over the first two postnatal weeks: soon after birth L-type, N-type, and P/Q-type voltage-gated calcium channels (VGCCs together mediated release, but after hearing onset P/Q-type VGCCs predominated. Blockade of P/Q-type VGCCs reduced the estimated quantal number for GABA/gly and glutamate transmission at P5-8 and the frequency of evoked miniature glycinergic events at P12-15, without apparent effects on spontaneous release of

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

    Science.gov (United States)

    Yates, George J.; Albright, Kevin L.; Turko, Bojan T.

    1993-10-01

    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 X 512 pixel array designed with four individual programmable bidirectional serial registers and eight output amplifiers permitting simultaneous readout of eight segments (128 horizontal X 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 are presented and the versatility/capabilities of the test station are reviewed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fahim, Farah [Fermilab

    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.

  6. Fabrication and Test of Pixelated CZT Detectors with Different Pixel Pitches and Thicknesses

    CERN Document Server

    Li, Q; Dowkontt, P; Martín, J; Beilicke, M; Jung, I; Groza, M; Bürger, A; De Geronimo, G; Krawczynski, H

    2008-01-01

    The main methods grown Cadmium Zinc Telluride (CZT) crystals with high yield and excellent homogeneity are Modified Horizontal Bridgman (MHB) and High Pressure Bridgman (HPB) processes, respectively. In this contribution, the readout system based on two 32-channel NCI-ASICs for pixellated CZT detector arrays has been developed and tested. The CZT detectors supplied by Orbotech (MHB) and eV products (HPB) are tested by NCI-ASIC readout system. The CZT detectors have an array of 8x8 or 11x11 pixel anodes fabricated on the anode surface with the area up to 2 cm x2 cm and the thickness of CZT detectors ranges from 0.5 cm to 1 cm. Energy spectra resolution and electron mobility-lifetime products of 8x8 pixels CZT detector with different thicknesses have been investigated.

  7. 毫米波多像元固态阵列接收机系统方案及关键技术%The System Solutions and Key Technology of a Millimeter-Wave Multi-Pixel Solid-State Array Receiver

    Institute of Scientific and Technical Information of China (English)

    陈翔; 李小军; 陈振华; 葛俊祥

    2016-01-01

    The basic concept and principle of multi-pixel array receivers are introduced in this paper. A G-band multi-pixel array receiver for space application is proposed, of which the structure and performance are presented, and the key technology of the receiver is discussed. Using integrated design method, a 2 × 2 multi-pixel array receiver operating at 183GHz is designed based on solid state nonlinear devices. The input local oscillator is Ku band signal, sideband separating is adopted in this array receiver. The whole receiver is integrated and compact, which can be widely used in many kinds of passive millimeter-wave imaging system.%文章介绍了毫米波多像元阵列接收机原理、技术优势及发展现状。针对空间应用,提出了一种基于固态器件的G波段毫米波多像元阵列接收机结构,并介绍了其关键技术。以固态器件为核心,通过本振变频一体化集成设计思想,设计实现一种中心频率183GHz的2×2像元固态阵列接收机。本振输入为Ku波段信号,接收机采用直接边带分离混频方式。整个接收机模块小型紧凑,可靠性高,可用于各种空间毫米波、亚毫米波无源探测系统中。

  8. Infrared single-pixel imaging utilising microscanning

    CERN Document Server

    Sun, Ming-Jie; Phillips, David B; Gibson, Graham M; Padgett, Miles J

    2015-01-01

    Since the invention of digital cameras there has been a concerted drive towards detector arrays with higher spatial resolution. Microscanning is a technique that provides a final higher resolution image by combining multiple images of a lower resolution. Each of these low resolution images is subject to a sub-pixel sized lateral displacement. In this work we apply the microscanning approach to an infrared single-pixel camera. For the same final resolution and measurement resource, we show that microscanning improves the signal-to-noise ratio (SNR) of reconstructed images by approximately 50%. In addition, this strategy also provides access to a stream of low-resolution 'preview' images throughout each high-resolution acquisition. Our work demonstrates an additional degree of flexibility in the trade-off between SNR and spatial resolution in single-pixel imaging techniques.

  9. Characterization of Pixel Sensors

    CERN Document Server

    Oliveira, Felipe Ferraz

    2017-01-01

    It was commissioned at CERN ATLAS pixel group a fluorescence setup for characterization of pixel sensors. The idea is to measure the energies of different targets to calibrate your sensor. It was measured four matrices (80, 95, 98 and 106) of the Investigator1 sensor with different deep PW using copper, iron and titanium as target materials. The matrix 80 has a higher gain (0.065 ± 0.002) and matrix 106 has a better energy resolution (0.05 ± 0.04). The noise of the setup is around 3.6 mV .

  10. ACS/WFC Pixel History, Bringing the Pixels Back to Science

    Science.gov (United States)

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

    2017-06-01

    Excess thermal energy within a Charged Coupled Device (CCD) results in excess electrical current that is trapped within the lattice structure of the electronics. This excess signal from the CCD itself can be present through multiple exposures, which will have an adverse effect on its science performance unless it is corrected for. The traditional way to correct for this extra charge is to take occasional long-exposure images with the camera shutter closed. These images, generally referred to as ``dark'' images, allow for the measurement of thermal-electron contamination at each pixel of the CCD. This so-called ``dark current'' can then be subtracted from the science images by re-scaling to the science exposure times. Pixels that have signal above a certain value are traditionally marked as ``hot'' and flagged in the data quality array. Many users will discard these pixels as being bad. However, these pixels may not be bad in the sense that they cannot be reliably dark-subtracted; if these pixels are shown to be stable over a given anneal period, the charge can be properly subtracted and the extra Poisson noise from this dark current can be taken into account and put into the error arrays.

  11. Pixel detector insertion

    CERN Multimedia

    CMS

    2015-01-01

    Insertion of the Pixel Tracker, the 66-million-channel device used to pinpoint the vertex of each colliding proton pair, located at the heart of the detector. The geometry of CMS is a cylinder lying on its side (22 meters long and 15 meters high in dia

  12. Pixel detector readout chip

    CERN Multimedia

    1991-01-01

    Close-up of a pixel detector readout chip. The photograph shows an aera of 1 mm x 2 mm containing 12 separate readout channels. The entire chip contains 1000 readout channels (around 80 000 transistors) covering a sensitive area of 8 mm x 5 mm. The chip has been mounted on a silicon detector to detect high energy particles.

  13. ALICE Silicon Pixel Detector

    CERN Multimedia

    Manzari, V

    2013-01-01

    The Silicon Pixel Detector (SPD) forms the innermost two layers of the 6-layer barrel Inner Tracking System (ITS). The SPD plays a key role in the determination of the position of the primary collision and in the reconstruction of the secondary vertices from particle decays.

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

    Science.gov (United States)

    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.

  15. Smart trigger logic for focal plane arrays

    Science.gov (United States)

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

    2014-03-25

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

  16. ATLAS ITk Pixel detector

    CERN Document Server

    Gemme, Claudia; The ATLAS collaboration

    2016-01-01

    The high luminosity upgrade of the LHC (HL-LHC) in 2026 will provide new challenge to the ATLAS tracker. The current inner detector will be replaced with a whole silicon tracker which will consist of a five barrel layer Pixel detector surrounded by a four barrel layer Strip detector. The expected high radiation level are requiring the development of upgraded silicon sensors as well as new a front-end chip. The dense tracking environment will require finer granularity detectors. The data rates will require new technologies for high bandwidth data transmission and handling. The current status of the HL-LHC ATLA Pixel detector developments as well as the various layout options will be reviewed.

  17. Alpine Pixel Detector Layout

    CERN Document Server

    Delebecque, P; The ATLAS collaboration; Geffroy, N; Massol, N; Rambure, T; Todorov, T

    2013-01-01

    A description of an optimized layout of pixel sensors based on a stave that combines both barrel and endcap module orientations. The mechanical stiffness of the structure is provided by carbon fiber shells spaced by carbon foam. The cooling of the modules is provided by two-phase $CO_{2}$ flowing in a thin titanium pipe glued inside the carbon fiber foam. The electrical services of all modules are provided by a single stave flex. This layout eliminates the need for separate barrel and endcap detector structures, and therefore the barrel services material in front of the endcap. The transition from barrel to endcap module orientation is optimized separately for each layer in order to minimize the active pixel area and the traversed material. The sparse module spacing in the endcap part of the stave allows for multiple fixation points, and for a stiff overall structure composed only of staves interconnected by stiff disks.

  18. Efficient defect pixel cluster detection and correction for Bayer CFA image sequences

    Science.gov (United States)

    Tajbakhsh, Touraj

    2011-01-01

    Image sensor arrays may have defect pixels, either originating from manufacturing or being developed over the lifetime of the image sensor array. Continuous defect pixel detection and correction performing during camera runtime is desirable. On-the-fly detection and correction is challenging since edges and high-frequency image content might get identified as defect pixel regions and intact pixels become corrupted during defect pixel replacement. We propose a table-based detection and correction method which by and by fills the non-volatile table during normal camera operation. In this work we model defect pixels and pixel clusters to be stuck to fixed values or at least fixed to a narrow value range whereas the local neighborhood of these pixels indicate a normal behavior. The idea is to temporally observe the value ranges of small group of pixels (e.g. 4x4 pixel blocks) and to decide about their defective condition depending on their variability with respect to their neighbor pixels. Our method is computationally efficient, requires no frame buffer, requires modest memory, and therefore is appropriate to operate in line-buffer based image signal processing (ISP) systems. Our results indicate high reliability in terms of detection rates and robustness against high-frequency image content. As part of the defect pixel replacement system we also propose a simple and efficient defect pixel correction method based on the mean of medians operating on the Bayer CFA image domain.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Y.; Torheim, O.; Hu-Guo, C. [Institut Pluridisciplinaire Hubert Curien (IPHC), 23 rue du loess, BP 28, 67037 Strasbourg (France); Degerli, Y. [CEA Saclay, IRFU/SEDI, 91191 Gif-sur-Yvette Cedex (France); Hu, Y., E-mail: yann.hu@iphc.cnrs.fr [Institut Pluridisciplinaire Hubert Curien (IPHC), 23 rue du loess, BP 28, 67037 Strasbourg (France)

    2013-03-11

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

  20. Pixelated neutron image plates

    Science.gov (United States)

    Schlapp, M.; Conrad, H.; von Seggern, H.

    2004-09-01

    Neutron image plates (NIPs) have found widespread application as neutron detectors for single-crystal and powder diffraction, small-angle scattering and tomography. After neutron exposure, the image plate can be read out by scanning with a laser. Commercially available NIPs consist of a powder mixture of BaFBr : Eu2+ and Gd2O3 dispersed in a polymer matrix and supported by a flexible polymer sheet. Since BaFBr : Eu2+ is an excellent x-ray storage phosphor, these NIPs are particularly sensitive to ggr-radiation, which is always present as a background radiation in neutron experiments. In this work we present results on NIPs consisting of KCl : Eu2+ and LiF that were fabricated into ceramic image plates in which the alkali halides act as a self-supporting matrix without the necessity for using a polymeric binder. An advantage of this type of NIP is the significantly reduced ggr-sensitivity. However, the much lower neutron absorption cross section of LiF compared with Gd2O3 demands a thicker image plate for obtaining comparable neutron absorption. The greater thickness of the NIP inevitably leads to a loss in spatial resolution of the image plate. However, this reduction in resolution can be restricted by a novel image plate concept in which a ceramic structure with square cells (referred to as a 'honeycomb') is embedded in the NIP, resulting in a pixelated image plate. In such a NIP the read-out light is confined to the particular illuminated pixel, decoupling the spatial resolution from the optical properties of the image plate material and morphology. In this work, a comparison of experimentally determined and simulated spatial resolutions of pixelated and unstructured image plates for a fixed read-out laser intensity is presented, as well as simulations of the properties of these NIPs at higher laser powers.

  1. The Kepler Pixel Response Function

    CERN Document Server

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

    2010-01-01

    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 measurement...

  2. ATLAS-IBL Pixel Upgrade

    CERN Document Server

    LaRosa, A; The ATLAS collaboration

    2010-01-01

    The upgrade for the ATLAS detector will undergo different phase towards Super-LHC. The first upgrade for the Pixel Detector will consist in the construction of a new pixel layer which will be installed during the first shutdown of the LHC machine (SLHC Phase I). The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of 3.2 cm. The IBL will require the development of several new technologies to cope with increase of radiation or pixel occupancy and also to improve the physics performance which will be achieved by reduction of the pixel size and of the material budget. Three different promising sensor technologies (Planar-Si, 3D-Si and Diamond) are currently under investigation for the pixel detector. An overview of the project with particular emphasis on pixel module studies, irradiation and beam test plans will be presented.

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

    Science.gov (United States)

    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.

  4. Pixel Stability in HST Advanced Camera for Surveys Images

    Science.gov (United States)

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

    2017-06-01

    Excess thermal energy present in a Charged Coupled Device (CCD) can result in additional electrical current that is propagated into individual pixels in an exposure. This excess signal from the CCD itself can be persistently existent through multiple exposures and can have an adverse effect on the detectors science performance unless properly flagged and corrected for. The traditional way to correct for this extra charge is to take occasional long-exposure images with the camera shutter closed to map the location of these pixels. These images, generally referred to as “dark” images, allow for the measurement of the thermal-electron contamination present in each pixel of the CCD lattice. This "dark current" can then be subtracted from the science images by re-scaling the dark to the science exposure times. Pixels that have signal above a certain threshold are traditionally marked as “hot” and flagged in the data quality array. Many users will discard these pixels as being bad because of this extra current. 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 Poisson noise from this hot pixel’s dark current can be taken into account. Here we present the results of a pixel history study that analyzes every individual pixel of the Hubble Space Telescope's (HST) Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) CCDs over time and allows pixels that were previously marked as bad to be brought back into the science image as a reliable pixel.

  5. Fabrication and Test of Pixelated CZT Detectors with Different Pixel Pitches and Thicknesses

    OpenAIRE

    Li, Q.; Garson, A.; Dowkontt, P.; Martin, J.; Beilicke, M; Jung, I.; Groza, M.; A. Burger; De Geronimo, G.; Krawczynski, H.; .

    2008-01-01

    The main methods grown Cadmium Zinc Telluride (CZT) crystals with high yield and excellent homogeneity are Modified Horizontal Bridgman (MHB) and High Pressure Bridgman (HPB) processes, respectively. In this contribution, the readout system based on two 32-channel NCI-ASICs for pixellated CZT detector arrays has been developed and tested. The CZT detectors supplied by Orbotech (MHB) and eV products (HPB) are tested by NCI-ASIC readout system. The CZT detectors have an array of 8x8 or 11x11 pi...

  6. Modelling semiconductor pixel detectors

    CERN Document Server

    Mathieson, K

    2001-01-01

    expected after 200 ps in most cases. The effect of reducing the charge carrier lifetime and examining the charge collection efficiency has been utilised to explore how these detectors would respond in a harsh radiation environment. It is predicted that over critical carrier lifetimes (10 ps to 0.1 ns) an improvement of 40 % over conventional detectors can be expected. This also has positive implications for fabricating detectors, in this geometry, from materials which might otherwise be considered substandard. An analysis of charge transport in CdZnTe pixel detectors has been performed. The analysis starts with simulation studies into the formation of contacts and their influence on the internal electric field of planar detectors. The models include a number of well known defect states and these are balanced to give an agreement with a typical experimental I-V curve. The charge transport study extends to the development of a method for studying the effect of charge sharing in highly pixellated detectors. The ...

  7. The ALICE pixel detector

    CERN Document Server

    Mercado Perez, J

    2002-01-01

    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. (3 refs).

  8. Pixelated gamma detector

    Energy Technology Data Exchange (ETDEWEB)

    Dolinsky, Sergei Ivanovich; Yanoff, Brian David; Guida, Renato; Ivan, Adrian

    2016-12-27

    A pixelated gamma detector includes a scintillator column assembly having scintillator crystals and optical transparent elements alternating along a longitudinal axis, a collimator assembly having longitudinal walls separated by collimator septum, the collimator septum spaced apart to form collimator channels, the scintillator column assembly positioned adjacent to the collimator assembly so that the respective ones of the scintillator crystal are positioned adjacent to respective ones of the collimator channels, the respective ones of the optical transparent element are positioned adjacent to respective ones of the collimator septum, and a first photosensor and a second photosensor, the first and the second photosensor each connected to an opposing end of the scintillator column assembly. A system and a method for inspecting and/or detecting defects in an interior of an object are also disclosed.

  9. Modeling Inter-Pixel Crosstalk in Teledyne Imaging Sensors H4RG Detectors

    CERN Document Server

    Dudik, R P; Dorland, B N; Veillette, D; Waczynski, A; Lane, B; Loose, M; Kan, E; Waterman, J; Pravdo, S

    2012-01-01

    CMOS-hybrid arrays have recently surfaced as competitive optical detectors for use in ground- and space-based astronomy. One source of error in these detectors that does not appear in more traditional CCD arrays is the inter-pixel capacitance component of crosstalk. In this paper we use a single pixel reset method to model inter-pixel capacitance (IPC). We combine this IPC model with a model for charge diffusion to estimate the total crosstalk on H4RG arrays. Finally, we compare our model results to Fe55 data obtained using an astrometric camera built to test the H4RG-B0 generation detectors.

  10. Planar Pixelations and Image Recognition

    CERN Document Server

    Rowekamp, Brandon

    2011-01-01

    Any subset of the plane can be approximated by a set of square pixels. This transition from a shape to its pixelation is rather brutal since it destroys geometric and topological information about the shape. Using a technique inspired by Morse Theory, we algorithmically produce a PL approximation of the original shape using only information from its pixelation. This approximation converges to the original shape in a very strong sense: as the size of the pixels goes to zero we can recover important geometric and topological invariants of the original shape such as Betti numbers, area, perimeter and curvature measures.

  11. Photovoltaic retinal prosthesis with high pixel density

    Science.gov (United States)

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

    2012-06-01

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

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

    Science.gov (United States)

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

    2013-12-01

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

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

    Science.gov (United States)

    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. Pixel History for Advanced Camera for Surveys Wide Field Channel

    Science.gov (United States)

    Borncamp, D.; Grogin, N.; Bourque, M.; Ogaz, S.

    2017-06-01

    Excess thermal energy present in a Charged Coupled Device (CCD) can result in additional electrical current. This excess charge is trapped within the silicon lattice structure of the CCD electronics. It can persist through multiple exposures and have an adverse effect on science performance of the detectors unless properly flagged and corrected for. The traditional way to correct for this extra charge is to take occasional long-exposure images with the camera shutter closed. These images, generally referred to as "dark" images, allow for the measurement of the thermal-electron contamination present in each pixel of the CCD lattice. This so-called "dark current" can then be subtracted from the science images by re-scaling the dark to the corresponding exposure times. Pixels that have signal above a certain threshold are traditionally marked as "hot" and flagged in the data quality array. Many users will discard these because of the extra current. However, these pixels may not be unusable because of an unreliable dark subtraction; if we find these pixels to be stable over an anneal period, we can properly subtract the charge and the extra Poisson noise from this dark current will be propagated into the error arrays. Here we present the results of a pixel history study that analyzes every individual pixel of the Hubble Space Telescope's (HST) Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) CCDs over time and allows pixels that were previously flagged as unusable to be brought back into the science image as a reliable pixel.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Matthew David, E-mail: Matt.Wilson@stfc.ac.uk [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Oxfordshire OX11 0QX (United Kingdom); Cernik, Robert [Henry Moseley X-ray Imaging Facility, School of Materials, University of Manchester (United Kingdom); Chen, Henry [Redlen Technologies, Saanichton, British Columbia (Canada); Hansson, Conny [Henry Moseley X-ray Imaging Facility, School of Materials, University of Manchester (United Kingdom); Iniewski, Kris [Redlen Technologies, Saanichton, British Columbia (Canada); Jones, Lawrence L.; Seller, Paul; Veale, Matthew C. [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Oxfordshire OX11 0QX (United Kingdom)

    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 20x20 application specific integrated circuit (ASIC) and data acquisition (DAQ) system. The detectors had an array of 20x20 pixels on a 250 {mu}m 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 {sup 241}Am 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 20x20 array. A large area 80x80 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  18. Diamond pixel modules

    CERN Document Server

    Gan, K K; Robichaud, A; Potenza, R; Kuleshov, S; Kagan, H; Kass, R; Wermes, N; Dulinski, W; Eremin, V; Smith, S; Sopko, B; Olivero, P; Gorisek, A; Chren, D; Kramberger, G; Schnetzer, S; Weilhammer, P; Martemyanov, A; Hugging, F; Pernegger, H; Lagomarsino, S; Manfredotti, C; Mishina, M; Trischuk, W; Dobos, D; Cindro, V; Belyaev, V; Duris, J; Claus, G; Wallny, R; Furgeri, A; Tuve, C; Goldstein, J; Sciortino, S; Sutera, C; Asner, D; Mikuz, M; Lo Giudice, A; Velthuis, J; Hits, D; Griesmayer, E; Oakham, G; Frais-Kolbl, H; Bellini, V; D'Alessandro, R; Cristinziani, M; Barbero, M; Schaffner, D; Costa, S; Goffe, M; La Rosa, A; Bruzzi, M; Schreiner, T; de Boer, W; Parrini, G; Roe, S; Randrianarivony, K; Dolenc, I; Moss, J; Brom, J M; Golubev, A; Mathes, M; Eusebi, R; Grigoriev, E; Tsung, J W; Mueller, S; Mandic, I; Stone, R; Menichelli, D

    2011-01-01

    With the commissioning of the LHC in 2010 and upgrades expected in 2015, ATLAS and CMS are planning to upgrade their innermost tracking layers with radiation hard technologies. Chemical Vapor Deposition diamond has been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle, CDF and all LHC experiments. This material is now being considered as a sensor material for use very close to the interaction region where the most extreme radiation conditions exist Recently the RD42 collaboration constructed, irradiated and tested polycrystalline and single-crystal chemical vapor deposition diamond sensors to the highest fluences expected at the super-LHC. We present beam test results of chemical vapor deposition diamond up to fluences of 1.8 x 10(16) protons/cm(2) illustrating that both polycrystalline and single-crystal chemical vapor deposition diamonds follow a single damage curve. We also present beam test results of irradiated complete diamond pixel m...

  19. Increased space-bandwidth product in pixel super-resolved lensfree on-chip microscopy

    Science.gov (United States)

    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.

  20. An integrating CMOS APS for X-ray imaging with an in-pixel preamplifier

    Science.gov (United States)

    Abdalla, M. A.; Fröjdh, C.; Petersson, C. S.

    2001-06-01

    We present in this paper an integrating CMOS Active Pixel Sensor (APS) circuit coated with scintillator type sensors for intra-oral dental X-ray imaging systems. The photosensing element in the pixel is formed by the p-diffusion on the n-well diode. The advantage of this photosensor is its very low direct absorption of X-rays compared to the other available photosensing elements in the CMOS pixel. The pixel features an integrating capacitor in the feedback loop of a preamplifier of a finite gain in order to increase the optical sensitivity. To verify the effectiveness of this in-pixel preamplification, a prototype 32×80 element CMOS active pixel array was implemented in a 0.8 μm CMOS double poly, n-well process with a pixel pitch of 50 μm. Measured results confirmed the improved optical sensitivity performance of the APS. Various measurements on device performance are presented.

  1. CMOS VLSI Active-Pixel Sensor for Tracking

    Science.gov (United States)

    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. From Pixels to Planets

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yates, G.J.; Albright, K.A. [Los Alamos National Lab., NM (United States); Turko, B.T. [Lawrence Berkeley Lab., CA (United States)

    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.

  4. Theoretical Study on the C-H Activation in Decarbonylation of Acetaldehyde by NiL2 (L=SO3CH3) Using Density Functional Theory

    Institute of Scientific and Technical Information of China (English)

    LIU Hongfei; JIA Tiekun; MIN Xinmin

    2014-01-01

    Density functional theory calculations were carried out to explore the potential energy surface (PES) associated with the gas-phase reaction of NiL2(L=SO3CH3) with acetone. The geometries and energies of the reactants, intermediates, products and transition states of the triplet ground potential energy surfaces of [Ni, O, C2, H4] were obtained at the B3LYP/6-311++G(d,p) levels in C,H,O atoms and B3LYP/Lanl2dz in Ni atom. It was found through our calculations that the decabonylation of acetaldehyde contains four steps including encounter complexation, C-C activation, aldehyde H-shift and nonreactive dissociation. The results revealed that C-C activation induced by NiL2(L=SO3CH3) led to the decarbonylation of acetaldehyde.

  5. CMS Barrel Pixel Detector Overview

    CERN Document Server

    Kästli, H C; Erdmann, W; Gabathuler, K; Hörmann, C; Horisberger, Roland Paul; König, S; Kotlinski, D; Meier, B; Robmann, P; Rohe, T; Streuli, S

    2007-01-01

    The pixel detector is the innermost tracking device of the CMS experiment at the LHC. It is built from two independent sub devices, the pixel barrel and the end disks. The barrel consists of three concentric layers around the beam pipe with mean radii of 4.4, 7.3 and 10.2 cm. There are two end disks on each side of the interaction point at 34.5 cm and 46.5 cm. This article gives an overview of the pixel barrel detector, its mechanical support structure, electronics components, services and its expected performance.

  6. Pixel readout ASIC for an APD based 2D X-ray hybrid pixel detector with sub-nanosecond resolution

    Energy Technology Data Exchange (ETDEWEB)

    Thil, Ch., E-mail: christophe.thil@ziti.uni-heidelberg.d [Heidelberg University, Institute of Computer Engineering, B6, 26, 68161 Mannheim (Germany); Baron, A.Q.R. [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Fajardo, P. [ESRF, Polygone Scientifique Louis Neel, 6, rue Jules Horowitz, 38000 Grenoble (France); Fischer, P. [Heidelberg University, Institute of Computer Engineering, B6, 26, 68161 Mannheim (Germany); Graafsma, H. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Rueffer, R. [ESRF, Polygone Scientifique Louis Neel, 6, rue Jules Horowitz, 38000 Grenoble (France)

    2011-02-01

    The fast response and the short recovery time of avalanche photodiodes (APDs) in linear mode make those devices ideal for direct X-ray detection in applications requiring high time resolution or counting rate. In order to provide position sensitivity, the XNAP project aims at creating a hybrid pixel detector with nanosecond time resolution based on a monolithic APD sensor array with 32 x32 pixels covering about 1 cm{sup 2} active area. The readout is implemented in a pixelated front-end ASIC suited for the readout of such arrays, matched to pixels of 280{mu}mx280{mu}m size. Every single channel features a fast transimpedance amplifier, a discriminator with locally adjustable threshold and two counters with high dynamic range and counting speed able to accumulate X-ray hits with no readout dead time. Additionally, the detector can be operated in list mode by time-stamping every single event with sub-nanosecond resolution. In a first phase of the project, a 4x4 pixel test module is built to validate the conceptual design of the detector. The XNAP project is briefly presented and the performance of the readout ASIC is discussed.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, G. [and others

    2001-03-08

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

  9. cMiCE a high resolution animal PET using continuous LSO with a statistics based positioning scheme

    CERN Document Server

    Joung Jin Hun; Lewellen, T K

    2002-01-01

    Objective: Detector designs for small animal scanners are currently dominated by discrete crystal implementations. However, given the small crystal cross-sections required to obtain very high resolution, discrete designs are typically expensive, have low packing fraction, reduced light collection, and are labor intensive to build. To overcome these limitations we have investigated the feasibility of using a continuous miniature crystal element (cMiCE) detector module for high resolution small animal PET applications. Methods: The detector module consists of a single continuous slab of LSO, 25x25 mm sup 2 in exposed cross-section and 4 mm thick, coupled directly to a PS-PMT (Hamamatsu R5900-00-C12). The large area surfaces of the crystal were polished and painted with TiO sub 2 and the short surfaces were left unpolished and painted black. Further, a new statistics based positioning (SBP) algorithm has been implemented to address linearity and edge effect artifacts that are inherent with conventional Anger sty...

  10. Detailed study of the column-based priority logic readout of Topmetal-II- CMOS pixel direct charge sensor

    CERN Document Server

    An, Mangmang; Gao, Chaosong; Han, Mikyung; Huang, Guangming; Ji, Rong; Li, Xiaoting; Mei, Yuan; Pei, Hua; Sun, Quan; Sun, Xiangming; Wang, Kai; Xiao, Le; Yang, Ping; Zhang, Wei; Zhou, Wei

    2016-01-01

    We present the detailed study of the digital readout of Topmetal-II- CMOS pixel direct charge sensor. Topmetal-II- is an integrated sensor with an array of 72X72 pixels each capable of directly collecting external charge through exposed metal electrodes in the topmost metal layer. In addition to the time-shared multiplexing readout of the analog output from Charge Sensitive Amplifiers in each pixel, hits are also generated through comparators with individually DAC settable thresholds in each pixel. The hits are read out via a column-based priority logic structure, retaining both hit location and time information. The in-array column-based priority logic is fully combinational hence there is no clock distributed in the pixel array. Sequential logic and clock are placed on the peripheral of the array. We studied the detailed working behavior and performance of this readout, and demonstrated its potential in imaging applications.

  11. A 2D 4×4 Channel Readout ASIC for Pixelated CdTe Detectors for Medical Imaging Applications

    OpenAIRE

    Macias-Montero, Jose-Gabriel; Sarraj, Maher; Chmeissani, Mokhtar; Martínez, Ricardo; Puigdengoles, Carles

    2015-01-01

    We present a 16-channel readout integrated circuit (ROIC) with nanosecond-resolution time to digital converter (TDC) for pixelated Cadmium Telluride (CdTe) gamma-ray detectors. The 4 × 4 pixel array ROIC is the proof of concept of the 10 × 10 pixel array readout ASIC for positron-emission tomography (PET) scanner, positron-emission mammography (PEM) scanner, and Compton gamma camera. The electronics of each individual pixel integrates an analog front-end with switchable gain, an analog to dig...

  12. High throughput optoelectronic smart pixel systems using diffractive optics

    Science.gov (United States)

    Chen, Chih-Hao

    1999-12-01

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

  13. Pixel detector system development at Diamond Light Source

    Science.gov (United States)

    Marchal, J.; Horswell, I.; Gimenez, E. N.; Tartoni, N.

    2010-10-01

    Hybrid pixel detectors consisting of an array of silicon photodiodes bump-bonded to CMOS read-out chips provide high signal-to-noise ratio and high dynamic range compared to CCD-based detectors and Image Plates. These detector features are important for SAXS experiments where a wide range of intensities are present in the images. For time resolved SAXS experiments, high frame rates are compulsory. The latest CMOS read-out chip developed by the MEDIPIX collaboration provides high frame rate and continuous acquisition mode. A read-out system for an array of MEDIPIX3 sensors is under development at Diamond Light Source. This system will support a full resolution frame rate of 1 kHz at a pixel counter depth of 12-bit and a frame rate of 30 kHz at a counter depth of 1 bit. Details concerning system design and MEDIPIX sensors characterization are presented.

  14. Integrated Lens Antennas for Multi-Pixel Receivers

    Science.gov (United States)

    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

  15. A CMOS active pixel sensor for retinal stimulation

    Science.gov (United States)

    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.

  16. WFC3 Pixel Area Maps

    Science.gov (United States)

    Kalirai, J. S.; Cox, C.; Dressel, L.; Fruchter, A.; Hack, W.; Kozhurina-Platais, V.; Mack, J.

    2010-04-01

    We present the pixel area maps (PAMs) for the WFC3/UVIS and WFC3/IR detectors, and discuss the normalization of these images. HST processed flt images suffer from geometric distortion and therefore have pixel areas that vary on the sky. The counts (electrons) measured for a source on these images depends on the position of the source on the detector, an effect that is implicitly corrected when these images are multidrizzled into drz files. The flt images can be multiplied by the PAMs to yield correct and uniform counts for a given source irrespective of its location on the image. To ensure consistency between the count rate measured for sources in drz images and near the center of flt images, we set the normalization of the PAMs to unity at a reference pixel near the center of the UVIS mosaic and IR detector, and set the SCALE in the IDCTAB equal to the square root of the area of this reference pixel. The implications of this choice for photometric measurements are discussed.

  17. VNR CMS Pixel detector replacement

    CERN Document Server

    2017-01-01

    Joel Butler, spokesperson of the CMS collaboration explains how a team from many different partner institutes installed a new detector in CMS. This detector is the silicon pixel detector and they’ve been working on it for about five years, to replace one of our existing detectors. This detectors measures particles closer to the beam than any of the other components of this huge detector behind me. It gives us the most precise picture of tracks as they come out of the collisions and expand and travel through the detector. This particular device has twice as many pixels, 120 million, as opposed to about 68 million in the old detector and it can take data faster and pump it out to the analysis more quickly. 00’53’’ Images of the descent, insertion and installation of first piece of the Pixel detector on Tue Feb 28. Images of the descent, insertion and installation of second piece of the Pixel and the two cylinders being joined.

  18. Status of the ATLAS pixel detector

    CERN Document Server

    Saavedra Aldo, F

    2005-01-01

    The ATLAS pixel detector is currently being constructed and will be installed in 2006 to be ready for commissioning at the Large Hadron Collider. The complete pixel detector is composed of three concentric barrels and six disks that are populated by 1744 ATLAS Pixel modules. The main components of the pixel module are the readout electronics and the silicon sensor whose active region is instrumented with rectangular pixels. The module has been designed to be able to survive 10 years of operation within the ATLAS detector. A brief description of the pixel detector will be presented with results and problems encountered during the production stage.

  19. A High-Speed CMOS Image Sensor with Global Electronic Shutter Pixels Using Pinned Diodes

    Science.gov (United States)

    Yasutomi, Keita; Tamura, Toshihiro; Furuta, Masanori; Itoh, Shinya; Kawahito, Shoji

    This paper describes a high-speed CMOS image sensor with a new type of global electronic shutter pixel. A global electronic shutter is necessary for imaging fast-moving objects without motion blur or distortion. The proposed pixel has two potential wells with pinned diode structure for two-stage charge transfer that enables a global electronic shuttering and reset noise canceling. A prototype high-speed image sensor fabricated in 0.18μm standard CMOS image sensor process consists of the proposed pixel array, 12-bit column-parallel cyclic ADC arrays and 192-channel digital outputs. The sensor achieves a good linearity at low-light intensity, demonstrating the perfect charge transfer between two pinned diodes. The input referred noise of the proposed pixel is measured to be 6.3 e-.

  20. Cosmic ray effects in microcalorimeter arrays

    Energy Technology Data Exchange (ETDEWEB)

    Stahle, C.K. E-mail: cak@lheapop.gsfc.nasa.gov; Boyce, K.R.; Brown, G.V.; Cottam, J.; Figueroa-Feliciano, E.; Galeazzi, M.; Kelley, R.L.; McCammon, D.; Porter, F.S.; Szymkowiak, A.E.; Tillotson, W.A

    2004-03-11

    We have identified signals resulting from cosmic rays and environmental gamma rays depositing energy in the pixels and in the silicon frame of the Astro-E2/X-Ray Spectrometer microcalorimeter array. Coincidences between pixels and between the array and an anti-coincidence detector determined the nature of the events. Pulse shapes and amplitudes from the cosmic ray events helped refine the thermal model of the array chip. We discuss how future arrays can be optimized either for the greatest background rejection or for the highest source count rates.

  1. The ATLAS Silicon Pixel Sensors

    CERN Document Server

    Alam, M S; Einsweiler, K F; Emes, J; Gilchriese, M G D; Joshi, A; Kleinfelder, S A; Marchesini, R; McCormack, F; Milgrome, O; Palaio, N; Pengg, F; Richardson, J; Zizka, G; Ackers, M; Andreazza, A; Comes, G; Fischer, P; Keil, M; Klasen, V; Kühl, T; Meuser, S; Ockenfels, W; Raith, B; Treis, J; Wermes, N; Gössling, C; Hügging, F G; Wüstenfeld, J; Wunstorf, R; Barberis, D; Beccherle, R; Darbo, G; Gagliardi, G; Gemme, C; Morettini, P; Musico, P; Osculati, B; Parodi, F; Rossi, L; Blanquart, L; Breugnon, P; Calvet, D; Clemens, J-C; Delpierre, P A; Hallewell, G D; Laugier, D; Mouthuy, T; Rozanov, A; Valin, I; Aleppo, M; Caccia, M; Ragusa, F; Troncon, C; Lutz, Gerhard; Richter, R H; Rohe, T; Brandl, A; Gorfine, G; Hoeferkamp, M; Seidel, SC; Boyd, GR; Skubic, P L; Sícho, P; Tomasek, L; Vrba, V; Holder, M; Ziolkowski, M; D'Auria, S; del Papa, C; Charles, E; Fasching, D; Becks, K H; Lenzen, G; Linder, C

    2001-01-01

    Prototype sensors for the ATLAS silicon pixel detector have been developed. The design of the sensors is guided by the need to operate them in the severe LHC radiation environment at up to several hundred volts while maintaining a good signal-to-noise ratio, small cell size, and minimal multiple scattering. The ability to be operated under full bias for electrical characterization prior to the attachment of the readout integrated circuit electronics is also desired.

  2. SAR Image Complex Pixel Representations

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

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

  3. Terahertz Array Receivers with Integrated Antennas

    Science.gov (United States)

    Chattopadhyay, Goutam; Llombart, Nuria; Lee, Choonsup; Jung, Cecile; Lin, Robert; Cooper, Ken B.; Reck, Theodore; Siles, Jose; Schlecht, Erich; Peralta, Alessandro; Thomas, Bertrand; Mehdi, Imran

    2011-01-01

    Highly sensitive terahertz heterodyne receivers have been mostly single-pixel. However, now there is a real need of multi-pixel array receivers at these frequencies driven by the science and instrument requirements. In this paper we explore various receiver font-end and antenna architectures for use in multi-pixel integrated arrays at terahertz frequencies. Development of wafer-level integrated terahertz receiver front-end by using advanced semiconductor fabrication technologies has progressed very well over the past few years. Novel stacking of micro-machined silicon wafers which allows for the 3-dimensional integration of various terahertz receiver components in extremely small packages has made it possible to design multi-pixel heterodyne arrays. One of the critical technologies to achieve fully integrated system is the antenna arrays compatible with the receiver array architecture. In this paper we explore different receiver and antenna architectures for multi-pixel heterodyne and direct detector arrays for various applications such as multi-pixel high resolution spectrometer and imaging radar at terahertz frequencies.

  4. How big is an OMI pixel?

    Science.gov (United States)

    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

  5. Statistical studies on the light output and energy resolution of small LSO single crystals with different surface treatments combined with various reflector materials

    CERN Document Server

    Heinrichs, U; Bussmann, N; Engels, R; Kemmerling, G; Weber, S; Ziemons, K

    2002-01-01

    The optimization of light output and energy resolution of scintillators is of special interest for the development of high resolution and high sensitivity PET. The aim of this work is to obtain statistically reliable results concerning optimal surface treatment of scintillation crystals and the selection of reflector material. For this purpose, raw, mechanically polished and etched LSO crystals (size 2x2x10 mm sup 3) were combined with various reflector materials (Teflon tape, Teflon matrix, BaSO sub 4) and exposed to a sup 2 sup 2 Na source. In order to ensure the statistical reliability of the results, groups of 10 LSO crystals each were measured for all combinations of surface treatment and reflector material. Using no reflector material the light output increased up to 551+-35% by mechanical polishing the surface compared to 100+-5% for raw crystals. Etching the surface increased the light output to 441+-29%. The untreated crystals had an energy resolution of 24.6+-4.0%. By mechanical polishing the surfac...

  6. Active-Pixel Image Sensor With Analog-To-Digital Converters

    Science.gov (United States)

    Fossum, Eric R.; Mendis, Sunetra K.; Pain, Bedabrata; Nixon, Robert H.

    1995-01-01

    Proposed single-chip integrated-circuit image sensor contains 128 x 128 array of active pixel sensors at 50-micrometer pitch. Output terminals of all pixels in each given column connected to analog-to-digital (A/D) converter located at bottom of column. Pixels scanned in semiparallel fashion, one row at time; during time allocated to scanning row, outputs of all active pixel sensors in row fed to respective A/D converters. Design of chip based on complementary metal oxide semiconductor (CMOS) technology, and individual circuit elements fabricated according to 2-micrometer CMOS design rules. Active pixel sensors designed to operate at video rate of 30 frames/second, even at low light levels. A/D scheme based on first-order Sigma-Delta modulation.

  7. Development of hybrid photon detectors with integrated silicon pixel readout for the RICH counters of LHCb

    CERN Document Server

    Alemi, M; Formenti, F; Gys, Thierry; Piedigrossi, D; Puertolas, D; Rosso, E; Snoeys, W; Wyllie, Ken H

    1999-01-01

    We report on the ongoing work towards a hybrid photon detector with integrated silicon pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment at the Large Hadron Collider at CERN. The photon detector is based $9 on a cross-focussed image intensifier tube geometry where the image is de-magnified by a factor of 4. The anode consists of a silicon pixel array, bump-bonded to a fast, binary readout chip with matching pixel electronics. The $9 performance of a half-scale prototype is presented, together with the developments and tests of a full-scale tube with large active area. Specific requirements for pixel front-end and readout electronics in LHCb are outlined, and $9 recent results obtained from pixel chips applicable to hybrid photon detector design are summarized.

  8. MONOLITHIC ACTIVE PIXEL MATRIX WITH BINARY COUNTERS IN AN SOI PROCESS.

    Energy Technology Data Exchange (ETDEWEB)

    DUPTUCH,G.; YAREMA, R.

    2007-06-07

    The design of a Prototype monolithic active pixel matrix, designed in a 0.15 {micro}m CMOS SOI Process, is presented. The process allowed connection between the electronics and the silicon volume under the layer of buried oxide (BOX). The small size vias traversing through the BOX and implantation of small p-type islands in the n-type bulk result in a monolithic imager. During the acquisition time, all pixels register individual radiation events incrementing the counters. The counting rate is up to 1 MHz per pixel. The contents of counters are shifted out during the readout phase. The designed prototype is an array of 64 x 64 pixels and the pixel size is 26 x 26 {micro}m{sup 2}.

  9. Pixel size and pitch measurements of liquid crystal spatial light modulator by optical diffraction

    Indian Academy of Sciences (India)

    Ravinder Kumar Banyal; B Raghavendra Prasad

    2005-08-01

    We present a simple technique for the determination of pixel size and pitch of liquid crystal (LC) based spatial light modulator (SLM). The proposed method is based on optical diffraction from pixelated LC panel that has been modeled as a two-dimensional array of rectangular apertures. A novel yet simple, two-plane measurement technique is implemented to circumvent the difficulty in absolute distance measurement. Experimental results are presented for electrically addressed twisted nematic LC-SLM removed from the display projector.

  10. Modulator and VCSEL-MSM smart pixels for parallel pipeline networking and signal processing

    Science.gov (United States)

    Chen, C.-H.; Hoanca, Bogdan; Kuznia, C. B.; Pansatiankul, Dhawat E.; Zhang, Liping; Sawchuk, Alexander A.

    1999-07-01

    TRANslucent Smart Pixel Array (TRANSPAR) systems perform high performance parallel pipeline networking and signal processing based on optical propagation of 3D data packets. The TRANSPAR smart pixel devices use either self-electro- optic effect GaAs multiple quantum well modulators or CMOS- VCSEL-MSM (CMOS-Vertical Cavity Surface Emitting Laser- Metal-Semiconductor-Metal) technology. The data packets transfer among high throughput photonic network nodes using multiple access/collision detection or token-ring protocols.

  11. CMOS digital pixel sensors: technology and applications

    Science.gov (United States)

    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.

  12. SOI pixel circuits with synchronized TMC for time-of-flight stigmatic imaging mass spectrometry

    CERN Document Server

    Watanabe, Kaori; Fujita, Youichi; Arai, Yasuo; Hazama, Hisanao

    2015-01-01

    We propose SOI pixel circuits with a synchronized time memory cell (TMC) for time-of-flight stigmatic imaging mass spectrometry. The circuits simultaneously detect the position and the fine/coarse flight time of an ion for the MALDI-ToF mass spectrometer. We discuss the circuit design and present the simulation results of a prototype detector comprised of a 32 x 32 pixel array in which each pixel pitch is 40 um and the time resolution is a minimum of 1 ns. The results of transient analysis demonstrate the fully correct synchronous operation at a 100-MHz clock frequency and simultaneous 32-word SRAM writing.

  13. CVD diamond pixel detectors for LHC experiments

    Energy Technology Data Exchange (ETDEWEB)

    Wedenig, R.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Wagner, A.; Walsh, A.M.; Weilhammer, P.; White, C.; Zeuner, W.; Ziock, H.; Zoeller, M.; Blanquart, L.; Breugnion, P.; Charles, E.; Ciocio, A.; Clemens, J.C.; Dao, K.; Einsweiler, K.; Fasching, D.; Fischer, P.; Joshi, A.; Keil, M.; Klasen, V.; Kleinfelder, S.; Laugier, D.; Meuser, S.; Milgrome, O.; Mouthuy, T.; Richardson, J.; Sinervo, P.; Treis, J.; Wermes, N

    1999-08-01

    This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described.

  14. CMS has a heart of pixels

    CERN Multimedia

    2003-01-01

    In the immediate vicinity of the collision point, CMS will be equipped with pixel detectors consisting of no fewer than 50 million pixels measuring 150 microns along each side. Each of the pixels, which receive the signal, is connected to its own electronic circuit by a tiny sphere (seen here in the electron microscope image) measuring 15 to 20 microns in diameter.

  15. Silicon Avalanche Pixel Sensor for High Precision Tracking

    CERN Document Server

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

  17. ASIC Readout Circuit Architecture for Large Geiger Photodiode Arrays

    Science.gov (United States)

    Vasile, Stefan; Lipson, Jerold

    2012-01-01

    The objective of this work was to develop a new class of readout integrated circuit (ROIC) arrays to be operated with Geiger avalanche photodiode (GPD) arrays, by integrating multiple functions at the pixel level (smart-pixel or active pixel technology) in 250-nm CMOS (complementary metal oxide semiconductor) processes. In order to pack a maximum of functions within a minimum pixel size, the ROIC array is a full, custom application-specific integrated circuit (ASIC) design using a mixed-signal CMOS process with compact primitive layout cells. The ROIC array was processed to allow assembly in bump-bonding technology with photon-counting infrared detector arrays into 3-D imaging cameras (LADAR). The ROIC architecture was designed to work with either common- anode Si GPD arrays or common-cathode InGaAs GPD arrays. The current ROIC pixel design is hardwired prior to processing one of the two GPD array configurations, and it has the provision to allow soft reconfiguration to either array (to be implemented into the next ROIC array generation). The ROIC pixel architecture implements the Geiger avalanche quenching, bias, reset, and time to digital conversion (TDC) functions in full-digital design, and uses time domain over-sampling (vernier) to allow high temporal resolution at low clock rates, increased data yield, and improved utilization of the laser beam.

  18. 1-D array of perforated diode neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    McNeil, Walter J. [Kansas State University, Mechanical and Nuclear Engineering Department, Manhattan, KS 66506 (United States)], E-mail: wjm4444@ksu.edu; Bellinger, Steven L.; Unruh, Troy C.; Henderson, Chris M.; Ugorowski, Phil; Morris-Lee, Bryce [Kansas State University, Mechanical and Nuclear Engineering Department, Manhattan, KS 66506 (United States); Taylor, Russell D. [Electronics Design Laboratory, Kansas State University, Manhattan, KS 66506 (United States); McGregor, Douglas S. [Kansas State University, Mechanical and Nuclear Engineering Department, Manhattan, KS 66506 (United States)], E-mail: mcgregor@ksu.edu

    2009-06-01

    Performance of a 4 cm long 64-pixel perforated diode neutron detector array is compared with an identical array of thin-film coated diodes. The perforated neutron detector design has been adapted to a 1-D pixel array capable of 120 {mu}m spatial resolution and counting efficiency greater than 12%. Deep vertical trenches filled with {sup 6}LiF provide outstanding improvement in efficiency over thin-film coated diode designs limited to only 4.5%. This work marks the final step towards the construction of a much larger array consisting of 1024 pixels spanning 10 cm. The larger detector array will be constructed with a sub-array of 64-pixel sensors, and will be used for small-angle neutron scattering experiments at the Spallation Neutron Source of Oak Ridge National Laboratory.

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

    Science.gov (United States)

    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.

  20. Making a trillion pixels dance

    Science.gov (United States)

    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

  1. Image pixel device using integrated organic electronic components

    Science.gov (United States)

    Swathi, K.; Narayan, K. S.

    2016-11-01

    We report a solution processed, monolithically integrated device similar to an imaging pixel element used in complementary metal-oxide semiconductor (CMOS) based cameras. This integrated pixel essentially consists of a pair of organic photodiode (OPD) and organic field effect transistor (OFET). The signal generated by the light responsive OPD drives the OFET to different output states to quantify the light intensity. The prerequisite of a low operating voltage OFET (polymer semiconductor and a self-assembled hybrid dielectric layer. A bulk heterojunction blend was used as the photo-active layer in the OPD along with suitable buffer layers for charge extraction. The material parameters were optimized to realize a suitable structure which clearly demonstrated the interplay of the OPD and OFET operations, thereby forming a roadmap for all-organic CMOS arrays.

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

    Science.gov (United States)

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

    2007-05-01

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

  3. Development of SOI pixel detector in Cracow

    CERN Document Server

    Bugiel, Szymon; Glab, Sebastian; Idzik, Marek; Moron, Jakub; Kapusta, Piotr Julian; Kucewicz, Wojciech; Turala, Michal

    2015-01-01

    This paper presents the design of a new monolithic Silicon-On-Insulator pixel sensor in $200~nm$ SOI CMOS technology. The main application of the proposed pixel detector is the spectroscopy, but it can also be used for the minimum ionizing particle (MIP) tracking in particle physics experiments. For this reason few different versions of pixel cells are developed: a source-follower based pixel for tracking, a low noise pixel with preamplifier for spectroscopy, and a self-triggering pixel for time and amplitude measurements. In addition the design of a Successive Approximation Register Analog-to-Digital Converter (SAR ADC) is also presented. A 10-bit SAR ADC is developed for spectroscopic measurements and a lower resolution 6-bit SAR ADC is integrated in the pixel matrix as a column ADC, for tracking applications.

  4. Design Optimization of Pixel Structure for α-Si based Uncooled Infrared Detector

    Directory of Open Access Journals (Sweden)

    Sudha Gupta

    2013-11-01

    Full Text Available In this paper authors present the design and simulation results achieved for pixel structure of amorphous Si (α-Si based bolometer array. Most uncooled IR detectors in the world are based on VOx material. But this is not a standard material in IC technology and has many inherent disadvantages. The α-Si, an alternative material with high TCR is becoming as popular. However, large TCR values, in this material are achieved only in films of high resistivity. To achieve TCR value more than 2.5%/K, α-Si film resistivity is ~ 80 ohms-cm. This gives rise to very large pixel resistance of the order of 100 Mega ohms depending upon the design of the leg structure. This high pixel resistance causes very large noise and hence lower sensitivity. If leg width or membrane thickness is increased in order to reduce the pixel resistance, then this results in higher thermal conductance which also decreases sensitivity. To overcome this problem, pixel structure is so designed that within a pixel, only part of the electrical conduction is through α-Si and rest is through metal. Simulation using Coventorware software has been done to optimize pixel resistance as well as thermal conductance through legs so that maximum sensitivity could be obtained. Optimization is also carried out in order to reduce sensitivity of pixel resistance to variation in material resistivity.

  5. The ALICE pixel detector upgrade

    Science.gov (United States)

    Reidt, F.

    2016-12-01

    The ALICE experiment at the CERN LHC is designed to study the physics of strongly interacting matter, and in particular the properties of the Quark-Gluon Plasma, using proton-proton, proton-nucleus and nucleus-nucleus collisions. The ALICE collaboration is preparing a major upgrade of the experimental apparatus to be installed during the second long LHC shutdown in the years 2019-2020. A key element of the ALICE upgrade is the new, ultra-light, high-resolution Inner Tracking System. With respect to the current detector, the new Inner Tracking System will significantly enhance the pointing resolution, the tracking efficiency at low transverse momenta, and the read-out rate capabilities. This will be obtained by seven concentric detector layers based on a Monolithic Active Pixel Sensor with a pixel pitch of about 30×30 μm2. A key feature of the new Inner Tracking System, which is optimised for high tracking accuracy at low transverse momenta, is the very low mass of the three innermost layers, which feature a material budget of 0.3% X0 per layer. This contribution presents the design goals and layout of the upgraded ALICE Inner Tracking System, summarises the R&D activities focussing on the technical implementation of the main detector components, and the projected detector performance.

  6. Serial powering of pixel modules

    CERN Document Server

    Stockmanns, Tobias; Hügging, Fabian Georg; Peric, I; Runólfsson, O; Wermes, Norbert

    2003-01-01

    Modern pixel detectors for the next generation of high-energy collider experiments like LHC use readout electronics in deep sub- micron technology. Chips in this technology need a low supply voltage of 2-2.5 V alongside high current consumption to achieve the desired performance. The high supply current leads to significant voltage drops in the long and low mass supply cables so that voltage fluctuations at the chips are induced, when the supply current changes. This problem scales with the number of modules when connected in parallel to the power supplies. An alternative powering scheme connects several modules in series resulting in a higher supply voltage but a lower current consumption of the chain and therefore a much lower voltage drop in the cables. In addition the amount of cables needed to supply the detector is vastly reduced. The concept and features of serial powering are presented and studies of the implementation of this technology as an alternative for the ATLAS pixel detector are shown. In par...

  7. A CMOS Active Pixel Sensor for Charged Particle Detection

    Energy Technology Data Exchange (ETDEWEB)

    Matis, Howard S.; Bieser, Fred; Kleinfelder, Stuart; Rai, Gulshan; Retiere, Fabrice; Ritter, Hans George; Singh, Kunal; Wurzel, Samuel E.; Wieman, Howard; Yamamoto, Eugene

    2002-12-02

    Active Pixel Sensor (APS) technology has shown promise for next-generation vertex detectors. This paper discusses the design and testing of two generations of APS chips. Both are arrays of 128 by 128 pixels, each 20 by 20 {micro}m. Each array is divided into sub-arrays in which different sensor structures (4 in the first version and 16 in the second) and/or readout circuits are employed. Measurements of several of these structures under Fe{sup 55} exposure are reported. The sensors have also been irradiated by 55 MeV protons to test for radiation damage. The radiation increased the noise and reduced the signal. The noise can be explained by shot noise from the increased leakage current and the reduction in signal is due to charge being trapped in the epi layer. Nevertheless, the radiation effect is small for the expected exposures at RHIC and RHIC II. Finally, we describe our concept for mechanically supporting a thin silicon wafer in an actual detector.

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

    Science.gov (United States)

    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.

  9. Segmentation and intensity estimation for microarray images with saturated pixels

    Directory of Open Access Journals (Sweden)

    Yang Yan

    2011-11-01

    Full Text Available Abstract Background Microarray image analysis processes scanned digital images of hybridized arrays to produce the input spot-level data for downstream analysis, so it can have a potentially large impact on those and subsequent analysis. Signal saturation is an optical effect that occurs when some pixel values for highly expressed genes or peptides exceed the upper detection threshold of the scanner software (216 - 1 = 65, 535 for 16-bit images. In practice, spots with a sizable number of saturated pixels are often flagged and discarded. Alternatively, the saturated values are used without adjustments for estimating spot intensities. The resulting expression data tend to be biased downwards and can distort high-level analysis that relies on these data. Hence, it is crucial to effectively correct for signal saturation. Results We developed a flexible mixture model-based segmentation and spot intensity estimation procedure that accounts for saturated pixels by incorporating a censored component in the mixture model. As demonstrated with biological data and simulation, our method extends the dynamic range of expression data beyond the saturation threshold and is effective in correcting saturation-induced bias when the lost information is not tremendous. We further illustrate the impact of image processing on downstream classification, showing that the proposed method can increase diagnostic accuracy using data from a lymphoma cancer diagnosis study. Conclusions The presented method adjusts for signal saturation at the segmentation stage that identifies a pixel as part of the foreground, background or other. The cluster membership of a pixel can be altered versus treating saturated values as truly observed. Thus, the resulting spot intensity estimates may be more accurate than those obtained from existing methods that correct for saturation based on already segmented data. As a model-based segmentation method, our procedure is able to identify inner

  10. Proceedings of PIXEL98 -- International pixel detector workshop

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, D.F.; Kwan, S. [eds.

    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. Serial Pixel Analog-to-Digital Converter

    Energy Technology Data Exchange (ETDEWEB)

    Larson, E D

    2010-02-01

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

  12. Toward VIP-PIX: A Low Noise Readout ASIC for Pixelated CdTe Gamma-Ray Detectors for Use in the Next Generation of PET Scanners

    OpenAIRE

    Macias-Montero, Jose-Gabriel; Sarraj, Maher; Chmeissani, Mokhtar; Puigdengoles, Carles; Lorenzo, Gianluca De; Martínez, Ricardo

    2013-01-01

    VIP-PIX will be a low noise and low power pixel readout electronics with digital output for pixelated Cadmium Telluride (CdTe) detectors. The proposed pixel will be part of a 2D pixel-array detector for various types of nuclear medicine imaging devices such as positron-emission tomography (PET) scanners, Compton gamma cameras, and positron-emission mammography (PEM) scanners. Each pixel will include a SAR ADC that provides the energy deposited with 10-bit resolution. Simultaneously, the self-...

  13. Lika vård, men inte för alla. En litteraturstudie om flyktingars erfarenheter av hälso- och sjukvård

    OpenAIRE

    Henriksson, Ida; Svensson, Susanne

    2014-01-01

    Bakgrund: Det finns 45 miljoner flyktingar i världen. Många flyktingar har svåra upplevelser bakom sig som kan påverka hälsan och de skattar sin hälsa som dålig. Flyktingar möter många hinder när de söker vård. Trots grundläggande rättigheter om bästa uppnåeliga hälsa för alla är vården för flyktingar godtycklig. Syfte: Syftet med litteraturstudien var att beskriva flyktingars erfarenheter av hälso-och sjukvård. Metod: Kvalitativa resultat ur sex kvalitativa och tre mixed-methodstudier kvalit...

  14. Diode-pumped dual-wavelength Nd:LSO laser at 1059 and 1067  nm with nearly diffraction-limited beam quality.

    Science.gov (United States)

    Huang, Xiaoxu; Lan, Jinglong; Lin, Zhi; Wang, Yi; Xu, Bin; Xu, Huiying; Cai, Zhiping; Xu, Xiaodong; Zhang, Jian; Xu, Jun

    2016-04-10

    We report a diode-pumped continuous-wave simultaneous dual-wavelength Nd:LSO laser at 1059 and 1067 nm. By employing a specially coated output coupler with relatively high transmissions at high-gain emission lines of 1075 and 1079 nm, the two low-gain emission lines, 1059 and 1067 nm, can be achieved, for the first time to our knowledge, with maximum output power of 1.27 W and slope efficiency of about 29.2%. The output power is only limited by the available pump power. Output beam quality is also measured to be about 1.19 and 1.21 of the beam propagation factors in the x and y directions, respectively.

  15. ATLAS Pixel Opto-Electronics

    CERN Document Server

    Arms, K E; Gan, K K; Holder, M; Jackson, P; Johnson, M; Kagan, H; Kass, R; Rahimi, A M; Roggenbuck, A; Rush, C; Schade, P; Smith, S; Ter-Antonian, R; Ziolkowski, M; Zoeller, M M

    2005-01-01

    We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission from the detector, and a Bi-Phase Mark decoder chip to recover the control data and 40 MHz clock received optically by a PIN diode. We have successfully implemented both ASICs in 0.25 micron CMOS technology using enclosed layout transistors and guard rings for increased radiation hardness. We present results of the performance of these chips, including irradiation with 24 GeV protons up to 61 Mrad (2.3 x 10e15 p/cm^2).

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  18. Pixel readout chip for the ATLAS experiment

    CERN Document Server

    Ackers, M; Blanquart, L; Bonzom, V; Comes, G; Fischer, P; Keil, M; Kühl, T; Meuser, S; Delpierre, P A; Treis, J; Raith, B A; Wermes, N

    1999-01-01

    Pixel detectors with a high granularity and a very large number of sensitive elements (cells) are a very recent development used for high precision particle detection. At the Large Hadron Collider LHC at CERN (Geneva) a pixel detector with 1.4*10/sup 8/ individual pixel cells is developed for the ATLAS detector. The concept is a hybrid detector. Consisting of a pixel sensor connected to a pixel electronics chip by bump and flip chip technology in one-to-one cell correspondence. The development and prototype results of the pixel front end chip are presented together with the physical and technical requirements to be met at LHC. Lab measurements are reported. (6 refs).

  19. Advanced pixel architectures for scientific image sensors

    CERN Document Server

    Coath, R; Godbeer, A; Wilson, M; Turchetta, R

    2009-01-01

    We present recent developments from two projects targeting advanced pixel architectures for scientific applications. Results are reported from FORTIS, a sensor demonstrating variants on a 4T pixel architecture. The variants include differences in pixel and diode size, the in-pixel source follower transistor size and the capacitance of the readout node to optimise for low noise and sensitivity to small amounts of charge. Results are also reported from TPAC, a complex pixel architecture with ~160 transistors per pixel. Both sensors were manufactured in the 0.18μm INMAPS process, which includes a special deep p-well layer and fabrication on a high resistivity epitaxial layer for improved charge collection efficiency.

  20. Operational Experience with the ATLAS Pixel Detector

    CERN Document Server

    Lantzsch, Kerstin; The ATLAS collaboration

    2016-01-01

    Run 2 of the LHC is providing new challenges to track and vertex reconstruction with higher energies, denser jets and higher rates. Therefore the ATLAS experiment has constructed the first 4-layer Pixel detector in HEP, installing a new Pixel layer, also called Insertable B-Layer (IBL). In addition the Pixel detector was refurbished with new service quarter panels to recover about 3% of defective modules lost during run 1 and a new optical readout system to readout the data at higher speed while reducing the occupancy when running with increased luminosity. The commissioning, operation and performance of the 4-layer Pixel Detector will be presented.

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

    Science.gov (United States)

    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. Single-pixel 3D imaging with time-based depth resolution

    CERN Document Server

    Sun, Ming-Jie; Gibson, Graham M; Sun, Baoqing; Radwell, Neal; Lamb, Robert; Padgett, Miles J

    2016-01-01

    Time-of-flight three dimensional imaging is an important tool for many applications, such as object recognition and remote sensing. Unlike conventional imaging approach using pixelated detector array, single-pixel imaging based on projected patterns, such as Hadamard patterns, utilises an alternative strategy to acquire information with sampling basis. Here we show a modified single-pixel camera using a pulsed illumination source and a high-speed photodiode, capable of reconstructing 128x128 pixel resolution 3D scenes to an accuracy of ~3 mm at a range of ~5 m. Furthermore, we demonstrate continuous real-time 3D video with a frame-rate up to 12 Hz. The simplicity of the system hardware could enable low-cost 3D imaging devices for precision ranging at wavelengths beyond the visible spectrum.

  3. FE-I4 Chip Development for Upgraded ATLAS Pixel Detector at LHC

    CERN Document Server

    Barbero, M; The ATLAS collaboration

    2010-01-01

    A new ATLAS pixel chip FE-I4 has been developed for use in upgraded LHC luminosity environments, including the near-term Insertable B-Layer upgrade. FE-I4 is designed in a 130 nm CMOS technology, presenting advantages in terms of radiation tolerance and digital logic density compared to the 0.25 μm CMOS technology used for the current ATLAS pixel IC, FE-I3. FE-I4 architecture is based on an array of 80×336 pixels, each 50×250 μm2, consisting of analog and digital sections. The analog pixel section is designed for low power consumption and compatibility to several sensor candidates. It is based on a two-stage architecture with a pre-amp AC-coupled to a second stage of amplification. It features leakage current compensation circuitry, local 4-bit pre-amp feedback tuning and a discriminator locally adjusted through 5 configuration bits. The digital architecture is based on a 4-pixel unit called Pixel Digital Region (PDR) allowing for local storage of hits in 5-deep data buffers at pixel level for the duratio...

  4. Pixel diamond detectors for excimer laser beam diagnostics

    Science.gov (United States)

    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).

  5. A Beam Monitor Using Silicon Pixel Sensors for Hadron Therapy

    CERN Document Server

    Wang, Zhen; Fan, Yan; Liu, Jun; Sun, Xiangming; Wang, Dong; Kang, Huili; Sun, Daming; Yang, Ping; Pei, Hua; Huang, Guangming; Xu, Nu; Gao, Chaosong; Xiao, Le

    2016-01-01

    We report the design and test results of a beam monitor developed for online monitoring in hadron therapy. The beam monitor uses eight silicon pixel sensors, \\textit{Topmetal-${II}^-$}, as the anode array. \\textit{Topmetal-${II}^-$} is a charge sensor designed in a CMOS 0.35 $\\mu$m technology. Each \\textit{Topmetal-${II}^-$} sensor has $72\\times72$ pixels. Each pixel size is about $83\\times83$ $\\mu$m$^2$. In our design the beam passes through the beam monitor without hitting the electrodes, making the beam monitor especially suitable for monitoring heavy ion beams. This design also reduces radiation damage to the beam monitor itself. The beam monitor is tested at the Heavy Ion Research Facility in Lanzhou (HIRFL) which provides a carbon ion beam. Results indicate that the beam monitor can measure position, incident angle and intensity of the beam with a position resolution better than 20 $\\mu$m, angular resolution about 0.5$^\\circ$ and intensity statistical accuracy better than 2$\\%$.

  6. A beam monitor using silicon pixel sensors for hadron therapy

    Science.gov (United States)

    Wang, Zhen; Zou, Shuguang; Fan, Yan; Liu, Jun; Sun, Xiangming; Wang, Dong; Kang, Huili; Sun, Daming; Yang, Ping; Pei, Hua; Huang, Guangming; Xu, Nu; Gao, Chaosong; Xiao, Le

    2017-03-01

    We report the design and test results of a beam monitor developed for online monitoring in hadron therapy. The beam monitor uses eight silicon pixel sensors, Topmetal-II-, as the anode array. Topmetal-II- is a charge sensor designed in a CMOS 0.35 μm technology. Each Topmetal-II- sensor has 72×72 pixels and the pixel size is 83×83 μm2. In our design, the beam passes through the beam monitor without hitting the electrodes, making the beam monitor especially suitable for monitoring heavy ion beams. This design also reduces radiation damage to the beam monitor itself. The beam monitor is tested with a carbon ion beam at the Heavy Ion Research Facility in Lanzhou (HIRFL). Results indicate that the beam monitor can measure position, incidence angle and intensity of the beam with a position resolution better than 20 μm, angular resolution about 0.5° and intensity statistical accuracy better than 2%.

  7. Design and TCAD simulation of double-sided pixelated low gain avalanche detectors

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Betta, Gian-Franco, E-mail: gianfranco.dallabetta@unitn.it [Dipartimento di Ingegneria Industriale, Università di Trento, Via Sommarive 9, 38123 Trento (Italy); TIFPA INFN, Via Sommarive 14, 38123 Trento (Italy); Pancheri, Lucio [Dipartimento di Ingegneria Industriale, Università di Trento, Via Sommarive 9, 38123 Trento (Italy); TIFPA INFN, Via Sommarive 14, 38123 Trento (Italy); Boscardin, Maurizio [Fondazione Bruno Kessler, Via Sommarive 18, 38123 Trento (Italy); TIFPA INFN, Via Sommarive 14, 38123 Trento (Italy); Paternoster, Giovanni [Fondazione Bruno Kessler, Via Sommarive 18, 38123 Trento (Italy); Piemonte, Claudio [Fondazione Bruno Kessler, Via Sommarive 18, 38123 Trento (Italy); TIFPA INFN, Via Sommarive 14, 38123 Trento (Italy); Cartiglia, Nicolo; Cenna, Francesca [INFN Sezione di Torino, Via P. Giuria 2, 10125 Torino (Italy); Bruzzi, Mara [Dipartimento di FIsica e Astronomia, Università di Firenze, and INFN Sezione di Firenze, Via Giovanni Sansone 1, 50019 Sesto Fiorentino (Italy)

    2015-10-01

    We introduce a double-sided variant of low gain avalanche detector, suitable for pixel arrays without dead-area in between the different read-out elements. TCAD simulations were used to validate the device concept and predict its performance. Different design options and selected simulation results are presented, along with the proposed fabrication process.

  8. MTF Issues in Small-Pixel-Pitch Planar Quantum IR Detectors

    Science.gov (United States)

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

    2014-08-01

    The current trend in quantum infrared (IR) detector development is the design of very small-pixel-pitch large arrays. From the previous 30 μm pitch, the standard pixel pitch today is 15 μm and is expected to decrease to 12 μm in the next few years. Furthermore, focal-plane arrays (FPAs) with pixel pitch as small as 10 μm have been demonstrated. Such ultrasmall-pixel pitches are very small compared with 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 on the order of 30 μm to 50 μm, i.e., three to five times the targeted pixel pitches. This has strong consequences for the modulation transfer function (MTF) of 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 an optimal MTF. Therefore, this issue has to be addressed to take full advantage of the pixel pitch reduction in terms of image resolution. The aim of this work is to investigate the evolution of the MTF of HgCdTe and InSb FPAs when decreasing the pixel pitch below 15 μm. Both experimental measurements and finite-element simulations are used to discuss this issue. Different scenarios are compared, namely deep mesa etch between pixels, internal drift, surface recombination, and thin absorbing layers.

  9. Land Cover Heterogeneity Effects on Sub-Pixel and Per-Pixel Classifications

    Directory of Open Access Journals (Sweden)

    Trung V. Tran

    2014-04-01

    Full Text Available Per-pixel and sub-pixel are two common classification methods in land cover studies. The characteristics of a landscape, particularly the land cover itself, can affect the accuracies of both methods. The objectives of this study were to: (1 compare the performance of sub-pixel vs. per-pixel classification methods for a broad heterogeneous region; and (2 analyze the impact of land cover heterogeneity (i.e., the number of land cover classes per pixel on both classification methods. The results demonstrated that the accuracy of both per-pixel and sub-pixel classification methods were generally reduced by increasing land cover heterogeneity. Urban areas, for example, were found to have the lowest accuracy for the per-pixel method, because they had the highest heterogeneity. Conversely, rural areas dominated by cropland and grassland had low heterogeneity and high accuracy. When a sub-pixel method was used, the producer’s accuracy for artificial surfaces was increased by more than 20%. For all other land cover classes, sub-pixel and per-pixel classification methods performed similarly. Thus, the sub-pixel classification was only advantageous for heterogeneous urban landscapes. Both creators and users of land cover datasets should be aware of the inherent landscape heterogeneity and its potential effect on map accuracy.

  10. Improved array illuminators.

    Science.gov (United States)

    Lohmann, A W; Sinzinger, S

    1992-09-10

    The job of an array illuminator is to provide an array of optical gates or smart pixels with photon power or with synchronous clock signals. So far it has been common to take the power from one big laser and distribute it to perhaps a million gates. An obvious alternative is to assign one private small source to each gate. We favor an in-between approach: a few medium-size sources share the job of providing photons. This hybrid approach has several advantages, such as better homogeneity, less coherent noise, and a distributed risk of source failure. We propose several setups and present some experimental results. Our concept calls for an array of incoherent point sources. We simulate such an array experimentally with a single source, which is virtually expanded into a source array by grating diffraction. Ordinarily these virtual sources are mutually coherent, which is undesirable for our aims. We destroy the mutual coherence by moving the grating during the photographic recording of the output array.

  11. Single-pixel camera with one graphene photodetector.

    Science.gov (United States)

    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.

  12. Signal modeling of charge sharing effect in simple pixelated CdZnTe detector

    Science.gov (United States)

    Kim, Jae Cheon; Kaye, William R.; He, Zhong

    2014-05-01

    In order to study the energy resolution degradation in 3D position-sensitive pixelated CdZnTe (CZT) detectors, a detailed detector system modeling package has been developed and used to analyze the detector performance. A 20 × 20 × 15 mm3 CZT crystal with an 11 × 11 simple-pixel anode array and a 1.72 mm pixel pitch was modeled. The VAS UM/TAT4 Application Specific Integrated Circuitry (ASIC) was used for signal read-out. Components of the simulation package include gamma-ray interactions with the CZT crystal, charge induction, electronic noise, pulse shaping, and ASIC triggering procedures. The charge induction model considers charge drift, trapping, diffusion, and sharing between pixels. This system model is used to determine the effects of electron cloud sharing, weighting potential non-uniformity, and weighting potential cross-talk which produce non-uniform signal responses for different gamma-ray interaction positions and ultimately degrade energy resolution. The effect of the decreased weighting potential underneath the gap between pixels on the total pulse amplitude of events has been studied. The transient signals induced by electron clouds collected near the gap between pixels may generate false signals, and the measured amplitude can be even greater than the photopeak. As the number of pixels that collect charge increases, the probability of side-neighbor events due to charge sharing significantly increases. If side-neighbor events are not corrected appropriately, the energy resolution of pixelated CZT detectors in multiple-pixel events degrades rapidly.

  13. Signal modeling of charge sharing effect in simple pixelated CdZnTe detector

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae C.; Kaye, William R.; He, Zhong [University of Michigan, Ann Arbor, MI (United States)

    2014-05-15

    In order to study the energy resolution degradation in 3D position-sensitive pixelated CdZnTe (CZT) detectors, a detailed detector system modeling package has been developed and used to analyze the detector performance. A 20 x 20 x 15 mm{sup 3} CZT crystal with an 11 x 11 simple-pixel anode array and a 1.72 mm pixel pitch was modeled. The VAS UM/TAT4 Application Specific Integrated Circuitry (ASIC) was used for signal read-out. Components of the simulation package include gamma-ray interactions with the CZT crystal, charge induction, electronic noise, pulse shaping, and ASIC triggering procedures. The charge induction model considers charge drift, trapping, diffusion, and sharing between pixels. This system model is used to determine the effects of electron cloud sharing, weighting potential non-uniformity, and weighting potential cross-talk which produce non-uniform signal responses for different gamma-ray interaction positions and ultimately degrade energy resolution. The effect of the decreased weighting potential underneath the gap between pixels on the total pulse amplitude of events has been studied. The transient signals induced by electron clouds collected near the gap between pixels may generate false signals, and the measured amplitude can be even greater than the photopeak. As the number of pixels that collect charge increases, the probability of side-neighbor events due to charge sharing significantly increases. If side-neighbor events are not corrected appropriately, the energy resolution of pixelated CZT detectors in multiple-pixel events degrades rapidly.

  14. Amorphous silicon pixel radiation detectors and associated thin film transistor electronics readout

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Mendez, V.; Drewery, J.; Hong, W.S.; Jing, T.; Kaplan, S.N.; Lee, H.; Mireshghi, A.

    1994-10-01

    We describe the characteristics of thin (1 {mu}m) and thick (>30 {mu}m) hydrogenated amorphous silicon p-i-n diodes which are optimized for detecting and recording the spatial distribution of charged particles, x-rays and {gamma} rays. For x-ray, {gamma} ray, and charged particle detection we can use thin p-i-n photosensitive diode arrays coupled to evaporated layers of suitable scintillators. For direct detection of charged particles with high resistance to radiation damage, we use the thick p-i-n diode arrays. Deposition techniques using helium dilution, which produce samples with low stress are described. Pixel arrays for flux exposures can be readout by transistor, single diode or two diode switches. Polysilicon charge sensitive pixel amplifiers for single event detection are described. Various applications in nuclear, particle physics, x-ray medical imaging, neutron crystallography, and radionuclide chromatography are discussed.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. Upgrades of the ATLAS Pixel Detector

    CERN Document Server

    Hügging, F; The ATLAS collaboration

    2013-01-01

    The upgrade for the ATLAS detector will undergo different phases towards HL-LHC. The first upgrade for the Pixel Detector (Phase 1) consists in the construction of a new pixel layer, which will be installed during the 1st long shutdown of the LHC machine (LS1) in 2013/14. The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of about 3.2 cm. The IBL requires the development of several new technologies to cope with the increase of radiation and pixel occupancy as well as to improve the physics performance of the existing pixel detector. The pixel size is reduced and the material budget is minimized by using new lightweight mechanical support materials and a CO2 based cooling system. For Phase 2 upgrade of LHC a complete new 4-layer pixel system is planned as part of a new all silicon Inner Detector. The increase in luminosity to about $5\\cdot 10^{34}$cm$^{-2}$s$^{-1}$ together with a total expected lifetime of ab...

  18. A new generation of small pixel pitch/SWaP cooled infrared detectors

    Science.gov (United States)

    Espuno, L.; Pacaud, O.; Reibel, Y.; Rubaldo, L.; Kerlain, A.; Péré-Laperne, N.; Dariel, A.; Roumegoux, J.; Brunner, A.; Kessler, A.; Gravrand, O.; Castelein, P.

    2015-10-01

    Following clear technological trends, the cooled IR detectors market is now in demand for smaller, more efficient and higher performance products. This demand pushes products developments towards constant innovations on detectors, read-out circuits, proximity electronics boards, and coolers. Sofradir was first to show a 10μm focal plane array (FPA) at DSS 2012, and announced the DAPHNIS 10μm product line back in 2014. This pixel pitch is a key enabler for infrared detectors with increased resolution. Sofradir recently achieved outstanding products demonstrations at this pixel pitch, which clearly demonstrate the benefits of adopting 10μm pixel pitch focal plane array-based detectors. Both HD and XGA Daphnis 10μm products also benefit from a global video datapath efficiency improvement by transitioning to digital video interfaces. Moreover, innovative smart pixels functionalities drastically increase product versatility. In addition to this strong push towards a higher pixels density, Sofradir acknowledges the need for smaller and lower power cooled infrared detector. Together with straightforward system interfaces and better overall performances, latest technological advances on SWAP-C (Size, Weight, Power and Cost) Sofradir products enable the advent of a new generation of high performance portable and agile systems (handheld thermal imagers, unmanned aerial vehicles, light gimbals etc...). This paper focuses on those features and performances that can make an actual difference in the field.

  19. Pixelated CdZnTe drift detectors

    DEFF Research Database (Denmark)

    Kuvvetli, Irfan; Budtz-Jørgensen, Carl

    2005-01-01

    A technique, the so-called Drift Strip Method (DSM), for improving the CdZnTe detector energy response to hard X-rays and gamma-rays was applied as a pixel geometry. First tests have confirmed that this detector type provides excellent energy resolution and imaging performance. We specifically...... report on the performance of 3 mm thick prototype CZT drift pixel detectors fabricated using material from eV-products. We discuss issues associated with detector module performance. Characterization results obtained from several prototype drift pixel detectors are presented. Results of position...

  20. LISe pixel detector for neutron imaging

    Science.gov (United States)

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

    2016-10-01

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

  1. Pixel detectors from fundamentals to applications

    CERN Document Server

    Rossi, Leonardo; Rohe, Tilman; Wermes, Norbert

    2006-01-01

    Pixel detectors are a particularly important class of particle and radiation detection devices. They have an extremely broad spectrum of applications, ranging from high-energy physics to the photo cameras of everyday life. This book is a general purpose introduction into the fundamental principles of pixel detector technology and semiconductor-based hybrid pixel devices. Although these devices were developed for high-energy ionizing particles and radiation beyond visible light, they are finding new applications in many other areas. This book will therefore benefit all scientists and engineers working in any laboratory involved in developing or using particle detection.

  2. Anode readout for pixellated CZT detectors

    Science.gov (United States)

    Narita, Tomohiko; Grindlay, Jonathan E.; Hong, Jaesub; Niestemski, Francis C.

    2004-02-01

    Determination of the photon interaction depth offers numerous advantages for an astronomical hard X-ray telescope. The interaction depth is typically derived from two signals: anode and cathode, or collecting and non-collecting electrodes. We present some preliminary results from our depth sensing detectors using only the anode pixel signals. By examining several anode pixel signals simultaneously, we find that we can estimate the interaction depth, and get sub-pixel 2-D position resolution. We discuss our findings and the requirements for future ASIC development.

  3. Wavelength scanning achieves pixel super-resolution in holographic on-chip microscopy

    Science.gov (United States)

    Luo, Wei; Göröcs, Zoltan; Zhang, Yibo; Feizi, Alborz; Greenbaum, Alon; Ozcan, Aydogan

    2016-03-01

    Lensfree holographic on-chip imaging is a potent solution for high-resolution and field-portable bright-field imaging over a wide field-of-view. Previous lensfree imaging approaches utilize a pixel super-resolution technique, which relies on sub-pixel lateral displacements between the lensfree diffraction patterns and the image sensor's pixel-array, to achieve sub-micron resolution under unit magnification using state-of-the-art CMOS imager chips, commonly used in e.g., mobile-phones. Here we report, for the first time, a wavelength scanning based pixel super-resolution technique in lensfree holographic imaging. We developed an iterative super-resolution algorithm, which generates high-resolution reconstructions of the specimen from low-resolution (i.e., under-sampled) diffraction patterns recorded at multiple wavelengths within a narrow spectral range (e.g., 10-30 nm). Compared with lateral shift-based pixel super-resolution, this wavelength scanning approach does not require any physical shifts in the imaging setup, and the resolution improvement is uniform in all directions across the sensor-array. Our wavelength scanning super-resolution approach can also be integrated with multi-height and/or multi-angle on-chip imaging techniques to obtain even higher resolution reconstructions. For example, using wavelength scanning together with multi-angle illumination, we achieved a halfpitch resolution of 250 nm, corresponding to a numerical aperture of 1. In addition to pixel super-resolution, the small scanning steps in wavelength also enable us to robustly unwrap phase, revealing the specimen's optical path length in our reconstructed images. We believe that this new wavelength scanning based pixel super-resolution approach can provide competitive microscopy solutions for high-resolution and field-portable imaging needs, potentially impacting tele-pathology applications in resource-limited-settings.

  4. Antenna-coupled bolometer arrays using transition-edgesensors

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Michael J.; Ade, Peter; Engargiola, Greg; Holzapfel,William; Lee,Adrian T.; O' Brient, Roger; Richards, Paul L.; Smith, Andy; Spieler, Helmuth; Tran, Huan

    2004-06-08

    We describe the development of an antenna-coupled bolometer array for use in a Cosmic Microwave Background polarization experiment. Prototype single pixels using double-slot dipole antennas and integrated microstrip band defining filters have been built and tested. Preliminary results of optical testing and simulations are presented. A bolometer array design based on this pixel will also be shown and future plans for application of the technology will be discussed.

  5. High Dynamic Range X-ray Detector Pixel Architectures Utilizing Charge Removal

    CERN Document Server

    Weiss, Joel T; Philipp, Hugh T; Becker, Julian; Chamberlain, Darol; Purohit, Prafull; Tate, Mark W; Gruner, Sol M

    2016-01-01

    Several charge integrating CMOS pixel front-ends utilizing charge removal techniques have been fabricated to extend dynamic range for x-ray diffraction applications at synchrotron sources and x-ray free electron lasers (XFELs). The pixels described herein build on the Mixed Mode Pixel Array Detector (MM-PAD) framework, developed previously by our group to perform high dynamic range imaging. These new pixels boast several orders of magnitude improvement in maximum flux over the MM-PAD, which is capable of measuring a sustained flux in excess of 10$^{8}$ x-rays/pixel/second while maintaining sensitivity to smaller signals, down to single x-rays. To extend dynamic range, charge is removed from the integration node of the front-end amplifier without interrupting integration. The number of times this process occurs is recorded by a digital counter in the pixel. The parameter limiting full well is thereby shifted from the size of an integration capacitor to the depth of a digital counter. The result is similar to t...

  6. USING BLOCKS OF SKEWERS FOR FASTER COMPUTATION OF PIXEL PURITY INDEX

    Energy Technology Data Exchange (ETDEWEB)

    J. THEILER; D. LAVENIER; ET AL

    2000-10-01

    The pixel purity index (PPI) algorithm proposed by Boardman, et al.1 identifies potential endmember pixels in multispectral imagery. The algorithm generates a large number of skewers (unit vectors in random directions), and then computes the dot product of each skewer with each pixel. The PPI is incremented for those pixels associated with the extreme values of the dot products. A small number of pixels (a subset of those with the largest PPI values) are selected as pure and the rest of the pixels in the image are expressed as linear mixtures of these pure endmembers. This provides a convenient and physically-motivated decomposition of the image in terms of a relatively few components. We report on a variant of the PPI algorithm in which blocks of B skewers are considered at a time. From the computation of B dot products, one can produce a much larger set of derived dot products that are associated with skewers that are linear combinations of the original B skewers. Since the derived dot products involve only scalar operations, instead of full vector dot products, they can be very cheaply computed. We will also discuss a hardware implementation on a field programmable gate array (FPGA) processor both of the original PPI algorithm and of the block-skewer approach. We will furthermore discuss the use of fast PPI as a front-end to more sophisticated algorithms for selecting the actual endmembers.

  7. Efficient phase contrast imaging in STEM using a pixelated detector. Part II: Optimisation of imaging conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hao, E-mail: hao.yang@materials.ox.ac.uk [University of Oxford, Department of Materials. Parks Rd, Oxford OX1 3PH (United Kingdom); Pennycook, Timothy J.; Nellist, Peter D. [University of Oxford, Department of Materials. Parks Rd, Oxford OX1 3PH (United Kingdom); EPSRC SuperSTEM Facility, Daresbury Laboratory, WA4 4AD (United Kingdom)

    2015-04-15

    In Part I of this series of two papers, we demonstrated the formation of a high efficiency phase-contrast image at atomic resolution using a pixelated detector in the scanning transmission electron microscope (STEM) with ptychography. In this paper we explore the technique more quantitatively using theory and simulations. Compared to other STEM phase contrast modes including annular bright field (ABF) and differential phase contrast (DPC), we show that the ptychographic phase reconstruction method using pixelated detectors offers the highest contrast transfer efficiency and superior low dose performance. Applying the ptychographic reconstruction method to DPC segmented detectors also improves the detector contrast transfer and results in less noisy images than DPC images formed using difference signals. We also find that using a minimum array of 16×16 pixels is sufficient to provide the highest signal-to-noise ratio (SNR) for imaging beam sensitive weak phase objects. Finally, the convergence angle can be adjusted to enhance the contrast transfer based on the spatial frequencies of the specimen under study. - Highlights: • High efficiency phase contrast transfer function (PCTF) can be achieved using pixelated detectors followed by a ptychographic reconstruction. • Ptychographic reconstruction offers the highest PCTF across the entire spatial frequency range compared to DPC and ABF. • Image simulations show that a ptychographic reconstruction using pixelated detectors offers a superior low dose performance for imaging weak phase objects. • Optimisation of imaging conditions using pixelated detectors are discussed by considering the contrast transfer function for various cases.

  8. Evaluation of Compton gamma camera prototype based on pixelated CdTe detectors

    OpenAIRE

    Y Calderón; Chmeissani, M.; Kolstein, M.; De Lorenzo, G.

    2014-01-01

    A proposed Compton camera prototype based on pixelated CdTe is simulated and evaluated in order to establish its feasibility and expected performance in real laboratory tests. The system is based on module units containing a 2×4 array of square CdTe detectors of 10×10 mm2 area and 2 mm thickness. The detectors are pixelated and stacked forming a 3D detector with voxel sizes of 2 × 1 × 2 mm3. The camera performance is simulated with Geant4-based Architecture for Medicine-Oriented Simulations(G...

  9. Measuring the scintillation decay time for different energy depositions in NaI:Tl, LSO:Ce and CeBr{sub 3} scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Swiderski, Lukasz, E-mail: lukasz.swiderski@ncbj.gov.pl; Moszynski, Marek; Syntfeld-Kazuch, Agnieszka; Szawlowski, Marek; Szczesniak, Tomasz

    2014-06-01

    This study presents a simple experimental setup for precise inspection of scintillation decay characteristics as a function of the energy deposited in scintillators. The results are discussed for NaI:Tl, LSO:Ce and CeBr{sub 3} crystals. The tested samples were coupled to a fast response R5320 photomultiplier from Hamamatsu. The decay time constants were measured by fitting the anode pulses of the PMT registered directly with a TDS5054B digital oscilloscope from Tektronix. Simple analog electronics composed of timing single channel analyzers, gate generators and coincidence/logic unit was used for selection of the deposited energy converted into light within the scintillator, and for triggering the scope to register relevant scintillation pulses. High precision of the experimental setup allowed for registration of non-proportionality curves for all samples. Moreover, non-proportionality was measured for fast and slow decay mode of NaI:Tl separately. The measurement was also used for inspection of possible differences in the pulse shapes originating from Compton scattering events and photoabsorption.

  10. Analysis of time resolution in a dual head LSO+PSPMT PET system using low pass filter interpolation and digital constant fraction discriminator techniques

    Energy Technology Data Exchange (ETDEWEB)

    Monzo, Jose M. [Digital Systems Design (DSD) Group, ITACA Institute, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)], E-mail: jmonfer@aaa.upv.es; Lerche, Christoph W.; Martinez, Jorge D.; Esteve, Raul; Toledo, Jose; Gadea, Rafael; Colom, Ricardo J.; Herrero, Vicente; Ferrando, Nestor; Aliaga, Ramon J.; Mateo, Fernando [Digital Systems Design (DSD) Group, ITACA Institute, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Sanchez, Filomeno [Nuclear Medical Physics Group, IFIC Institute, Consejo Superior de Investigaciones Cientificas (CSIC), 46980 Paterna (Spain); Mora, Francisco J. [Digital Systems Design (DSD) Group, ITACA Institute, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Benlloch, Jose M. [Nuclear Medical Physics Group, IFIC Institute, Consejo Superior de Investigaciones Cientificas (CSIC), 46980 Paterna (Spain); Sebastia, Angel [Digital Systems Design (DSD) Group, ITACA Institute, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)

    2009-06-01

    PET systems need good time resolution to improve the true event rate, random event rejection, and pile-up rejection. In this study we propose a digital procedure for this task using a low pass filter interpolation plus a Digital Constant Fraction Discriminator (DCFD). We analyzed the best way to implement this algorithm on our dual head PET system and how varying the quality of the acquired signal and electronic noise analytically affects timing resolution. Our detector uses two continuous LSO crystals with a position sensitive PMT. Six signals per detector are acquired using an analog electronics front-end and these signals are processed using an in-house digital acquisition board. The test bench developed simulates the electronics and digital algorithms using Matlab. Results show that electronic noise and other undesired effects have a significant effect on the timing resolution of the system. Interpolated DCFD gives better results than non-interpolated DCFD. In high noise environments, differences are reduced. An optimum delay selection, based on the environment noise, improves time resolution.

  11. Adopt a Pixel Photographs: 2013-Present

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The photographs in the Adopt a Pixel collection were provided by volunteers with a digital camera, a Global Positioning System (GPS), and a compass or a smart mobile...

  12. Adopt a Pixel Photographs: 2013-Present

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The photographs in the Adopt a Pixel collection were provided by volunteers with a digital camera, a Global Positioning System (GPS), and a compass or a smart mobile...

  13. Adopt a Pixel Photographs: 2013-Present

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The photographs in the Adopt a Pixel collection were provided by volunteers with a digital camera, a Global Positioning System (GPS), and a compass or a smart...

  14. Simulation study of pixel detector charge digitization

    Science.gov (United States)

    Wang, Fuyue; Nachman, Benjamin; Sciveres, Maurice; Lawrence Berkeley National Laboratory Team

    2017-01-01

    Reconstruction of tracks from nearly overlapping particles, called Tracking in Dense Environments (TIDE), is an increasingly important component of many physics analyses at the Large Hadron Collider as signatures involving highly boosted jets are investigated. TIDE makes use of the charge distribution inside a pixel cluster to resolve tracks that share one of more of their pixel detector hits. In practice, the pixel charge is discretized using the Time-over-Threshold (ToT) technique. More charge information is better for discrimination, but more challenging for designing and operating the detector. A model of the silicon pixels has been developed in order to study the impact of the precision of the digitized charge distribution on distinguishing multi-particle clusters. The output of the GEANT4-based simulation is used to train neutral networks that predict the multiplicity and location of particles depositing energy inside one cluster of pixels. By studying the multi-particle cluster identification efficiency and position resolution, we quantify the trade-off between the number of ToT bits and low-level tracking inputs. As both ATLAS and CMS are designing upgraded detectors, this work provides guidance for the pixel module designs to meet TIDE needs. Work funded by the China Scholarship Council and the Office of High Energy Physics of the U.S. Department of Energy under contract DE-AC02-05CH11231.

  15. Sub-pixel calibration for Weak Lensing and Astrometry

    Science.gov (United States)

    Shao, Michael

    We have recently developed and demonstrated a new method of sub-pixel detector calibration that offers orders of magnitude improvement in astrometry with CCD focal planes. Using this technique we have demonstrated centroiding of images to 1e 5 lambda/D in laboratory conditions. Our method allows reconstructing the true optical point spread function (PSF) of a telescope from pixelated stellar images. Although this technique was originally developed for centroiding of images across a large focal plane, it can also be applied to weak lensing program on WFIRST. We use a laser metrology technique to measure geometric imperfections in the focal plane array from pixel placement errors to non-uniform quantum efficiency (QE) within every pixel. With precise sub-pixel calibration one can use dithered images (e.g., a 2×2 dither) to derive Nyquist-sampled image of stars. The WFIRST telescope has a large 0.28 sq.deg field of view (FOV) with theoretical PSF varying considerably over that FOV. However, even at high galactic latitude there will be over 1,000 stars brighter than 16 mag and, with Nyquist-sampled images, it should be possible to calculate the spatially varying PSF at 1,000 locations in the focal plane. With knowledge of the optical PSF and sub-pixel calibration of the detector, one can remove biases in the shapes of galaxies introduced by the spatially varying PSF. The technique of sub-pixel calibration has so far only been demonstrated in with visible CCD detectors and applied to achieve ultra-precise image centroiding. The purpose of this proposal is to extend the technique of removing biases in the shape of galaxies due to pixilation and spatially varying PSF and to extend the calibration of visible detectors to NIR detectors. The new technique could be used to enable 4 10 microarcsecond (μas) astrometry within the 0.28 sq.deg FOV of the WFIRST telescope. Using the upcoming Gaia catalogue accurate to ~10 μas, we will be able to stitch the HgCdTe arrays on

  16. Design optimization of Pixel Structure for α-Si based uncooled Infrared detector

    Directory of Open Access Journals (Sweden)

    Sudha Gupta

    2013-12-01

    Full Text Available In this paper authors present the design and simulation results achieved for pixel structure of amorphous Si (α-Si based bolometer array. Most uncooled IR detectors in the world are based on VOx material. But this is not a standard material in IC technology and has many inherent disadvantages. The α-Si, an alternative material with high TCR is becoming as popular. However, large TCR values, in this material are achieved only in films of high resistivity. To achieve TCR value more than 2.5%/K, α-Si film resistivity is ~ 80 ohms-cm. This gives rise to very large pixel resistance of the order of 100 Mega ohms depending upon the design of the leg structure. This high pixel resistance causes very large noise and hence lower sensitivity. If leg width or membrane thickness is increased in order to reduce the pixel resistance, then this results in higher thermal conductance which also decreases sensitivity. To overcome this problem, pixel structure is so designed that within a pixel, only part of the electrical conduction is through α-Si and rest is through metal. Simulation using Coventorware software has been done to optimize pixel resistance as well as thermal conductance through legs so that maximum sensitivity could be obtained. Optimization is also carried out in order to reduce sensitivity of pixel resistance to variation in material resistivity.Defence Science Journal, 2013, 63(6, pp.581-588, DOI:http://dx.doi.org/10.14429/dsj.63.5758

  17. Region based elimination of noise pixels towards optimized classifier models for skin pixel detection

    Directory of Open Access Journals (Sweden)

    Gagandeep Kaur

    2015-03-01

    Full Text Available The extraction of the skin pixels in a human image and rejection of non-skin pixels is called the skin segmentation. Skin pixel detection is the process of extracting the skin pixels in a human image which is typically used as a pre-processing step to extract the face regions from human image. In past, there are several computer vision approaches and techniques have been developed for skin pixel detection. In the process of skin detection, given pixels are been transformed into an appropriate color space such as RGB, HSV etc. And then skin classifier model have been applied to label the pixel into skin or non-skin regions. Here in this research a “Region based elimination of noise pixels and performance analysis of classifier models for skin pixel detection applied on human images” would be performed which involve the process of image representation in color models, elimination of non-skin pixels in the image, and then pre-processing and cleansing of the collected data, feature selection of the human image and then building the model for classifier. In this research and implementation of skin pixels classifier models are proposed with their comparative performance analysis. The definition of the feature vector is simply the selection of skin pixels from the human image or stack of human images. The performance is evaluated by comparing and analysing skin colour segmentation algorithms. During the course of research implementation, efforts are iterative which help in selection of optimized skin classifier based on the machine learning algorithms and their performance analysis.

  18. First operation of a pixel imaging matrix based on DEPFET pixels

    CERN Document Server

    Fischer, P; Klein, P; Löcker, M; Lutz, Gerhard; Neeser, W; Strüder, L; Wermes, N

    2000-01-01

    In the DEPFET pixel concept the detected incident radiation is directly sensed and amplified by a JFET integrated in every pixel cell. While the DEPFET detector principle has already been demonstrated previously on single pixel structures, we present here the first successful operation of a large $32 \\times 32$ DEPFET pixel matrix as an imaging device. The matrix has been exposed to 60 keV gamma rays of a $^{241}$Am source and has been scanned using an IR laser. The principle of operation as well as the charge collection in the structure and possible improvements are discussed.

  19. Micromirror Arrays for Adaptive Optics

    Energy Technology Data Exchange (ETDEWEB)

    Carr, E.J.

    2000-08-07

    The long-range goal of this project is to develop the optical and mechanical design of a micromirror array for adaptive optics that will meet the following criteria: flat mirror surface ({lambda}/20), high fill factor (> 95%), large stroke (5-10 {micro}m), and pixel size {approx}-200 {micro}m. This will be accomplished by optimizing the mirror surface and actuators independently and then combining them using bonding technologies that are currently being developed.

  20. Spatial clustering of pixels of a multispectral image

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Spatial clustering of pixels of a multispectral image

    Science.gov (United States)

    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.

  2. Tests of the gated mode for Belle II pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Prinker, Eduard [Max-Planck-Institute for Physics, Munich (Germany); Collaboration: Belle II-Collaboration

    2015-07-01

    DEPFET pixel detectors offer intrinsic amplification and very high signal to noise ratio. They form an integral building block for the vertex detector system of the Belle II experiment, which will start data taking in the year 2017 at the SuperKEKB Collider in Japan. A special Test board (Hybrid4) is used, which contains a small version of the DEPFET sensor with a read-out (DCD) and a steering chip (Switcher) attached, both controlled by a field-programmable gate array (FPGA) as the central interface to the computer. In order to keep the luminosity of the collider constant over time, the particle bunch currents have to be topped off by injecting additional bunches at a rate of 50 Hz. The particles in the daughter bunches produce a high rate of background (noisy bunches) for a short period of time, saturating the occupancy of the sensor. Operating the DEPFET sensor in a Gated Mode allows preserving the signals from collisions of normal bunches while protecting the pixels from background signals of the passing noisy bunches. An overview of the Gated Mode and first results is presented.

  3. Solution processed integrated pixel element for an imaging device

    Science.gov (United States)

    Swathi, K.; Narayan, K. S.

    2016-09-01

    We demonstrate the implementation of a solid state circuit/structure comprising of a high performing polymer field effect transistor (PFET) utilizing an oxide layer in conjunction with a self-assembled monolayer (SAM) as the dielectric and a bulk-heterostructure based organic photodiode as a CMOS-like pixel element for an imaging sensor. Practical usage of functional organic photon detectors requires on chip components for image capture and signal transfer as in the CMOS/CCD architecture rather than simple photodiode arrays in order to increase speed and sensitivity of the sensor. The availability of high performing PFETs with low operating voltage and photodiodes with high sensitivity provides the necessary prerequisite to implement a CMOS type image sensing device structure based on organic electronic devices. Solution processing routes in organic electronics offers relatively facile procedures to integrate these components, combined with unique features of large-area, form factor and multiple optical attributes. We utilize the inherent property of a binary mixture in a blend to phase-separate vertically and create a graded junction for effective photocurrent response. The implemented design enables photocharge generation along with on chip charge to voltage conversion with performance parameters comparable to traditional counterparts. Charge integration analysis for the passive pixel element using 2D TCAD simulations is also presented to evaluate the different processes that take place in the monolithic structure.

  4. Pixel Based Off-line Signature Verification System

    Directory of Open Access Journals (Sweden)

    Anik Barua

    2015-01-01

    Full Text Available The verification of handwritten signatures is one of the oldest and the most popular authentication methods all around the world. As technology improved, different ways of comparing and analyzing signatures become more and more sophisticated. Since the early seventies, people have been exploring how computers can fully take over the task of signature verification and tried different methods. However, none of them is satisfactory enough and time consuming too. Therefore, our proposed pixel based offline signature verification system is one of the fastest and easiest ways to authenticate any handwritten signature we have ever found. For signature acquisition, we have used scanner. Then we have divided the signature image into 2D array and calculated the hexadecimal RGB value of each pixel. After that, we have calculated the total percentage of matching. If the percentage of matching is more than 90, the signature is considered as valid otherwise invalid. We have experimented on more than 35 signatures and the result of our experiment is quite impressive. We have made the whole system web based so that the signature can be verified from anywhere. The average execution time for signature verification is only 0.00003545 second only.

  5. The pixel hybrid photon detectors for the LHCb-RICH project

    CERN Document Server

    Gys, Thierry

    2001-01-01

    This paper describes a hybrid photon detector with integrated silicon pixel readout to be used in the ring imaging Cherenkov detectors of the LHCb experiment. The photon detector is based on a cross-focussed image intensifier tube geometry where the image is de-magnified by a factor of 5. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The paper starts with the general specification of the baseline option. Followed by a summary of the main results achieved so far during the R&D phase. It concludes with a description of the remaining work towards the final photon detector. (17 refs).

  6. A tiled CCD detector with 2x2 array and tapered fibre optics for electron microscopy

    CERN Document Server

    Faruqi, A R; Cattermole, D M; Stubbings, S

    2002-01-01

    Charge coupled devices (CCD)-based detectors have made a major impact on data collection in electron microscopy over the past few years. There have been a number of successful applications of CCDs in electron crystallography of two-dimensional protein crystal arrays but high-resolution imaging has been hampered by the relatively poor spatial resolution (and fewer independent pixels) compared to film. A partial solution to this problem, presented in this paper, are to design detectors with larger effective pixel sizes and with more pixels. A CCD detector with a much greater number of 'independent' pixels, achieved by tiling a 2x2 array of CCDs, each of which has 1242x1152 pixels is described here. The sensitive area of the detector, using fibre optics with a demagnification of 2.5 : 1, is 140x130 mm sup 2; the pixel size is 56 mu m square and there is a total of approx 2500x2300 pixels.

  7. A logarithmic low dark current CMOS pixel

    Science.gov (United States)

    Brunetti, Alessandro Michel; Choubey, Bhaskar

    2016-04-01

    High dynamic range pixels are required in a number of automotive and scientific applications. CMOS pixels provide different approaches to achieve this. However, these suffer from poor performance under low light conditions due to inherently high leakage current that is present in CMOS processes, also known as dark current. The typical approach to reduce this dark current involves process modifications. Nevertheless, energy considerations suggest that the leakage current will be close to zero at a close to zero voltage on the photodiode. Hence, the reduction in dark current can be achieved by forcing a zero voltage across the photodiode. In this paper, a novel logarithmic CMOS pixel design capable of reducing dark current without any process modifications is proposed. This pixel is also able to produce a wide dynamic range response. This circuit utilizes two current mirrors to force the in-pixel photodiode at a close to zero voltage. Additionally, a bias voltage is used to reduce a higher order effect known as Drain Induced Barrier Lowering (DIBL). In fact, the contribution of this effect can be compensated by increasing the body effect. In this paper, we studied the consequences of a negative bias voltage applied to the body of the current mirror pair to compensate for the DIBL effect thereby achieving a very small voltage drop on the photodiode and consequently, a higher sensitivity in low light conditions.

  8. Radiation Tolerance of CMOS Monolithic Active Pixel Sensors with Self-Biased Pixels

    CERN Document Server

    Deveaux, M; Besson, A; Claus, G; Colledani, C; Dorokhov, M; Dritsa, C; Dulinski, W; Fröhlich, I; Goffe, M; Grandjean, D; Heini, S; Himmi, A; Hu, C; Jaaskelainen, K; Müntz, C; Shabetai, A; Stroth, J; Szelezniak, M; Valin, I; Winter, M

    2009-01-01

    CMOS Monolithic Active Pixel Sensors (MAPS) are proposed as a technology for various vertex detectors in nuclear and particle physics. We discuss the mechanisms of ionizing radiation damage on MAPS hosting the the dead time free, so-called self bias pixel. Moreover, we discuss radiation hardened sensor designs which allow operating detectors after exposing them to irradiation doses above 1 Mrad

  9. High performance compound semiconductor SPAD arrays

    Science.gov (United States)

    Harmon, Eric S.; Naydenkov, Mikhail; Bowling, Jared

    2016-05-01

    Aggregated compound semiconductor single photon avalanche diode (SPAD) arrays are emerging as a viable alternative to the silicon photomultiplier (SiPM). Compound semiconductors have the potential to surpass SiPM performance, potentially achieving orders of magnitude lower dark count rates and improved radiation hardness. New planar processing techniques have been developed to enable compound semiconductor SPAD devices to be produced with pixel pitches of 11 - 25 microns, with thousands of SPADs per array.

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

    Science.gov (United States)

    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.

  11. The pin pixel detector--neutron imaging

    CERN Document Server

    Bateman, J E; Derbyshire, G E; Duxbury, D M; Marsh, A S; Rhodes, N J; Schooneveld, E M; Simmons, J E; Stephenson, R

    2002-01-01

    The development and testing of a neutron gas pixel detector intended for application in neutron diffraction studies is reported. Using standard electrical connector pins as point anodes, the detector is based on a commercial 100 pin connector block. A prototype detector of aperture 25.4 mmx25.4 mm has been fabricated, giving a pixel size of 2.54 mm which matches well to the spatial resolution typically required in a neutron diffractometer. A 2-Dimensional resistive divide readout system has been adapted to permit the imaging properties of the detector to be explored in advance of true pixel readout electronics. The timing properties of the device match well to the requirements of the ISIS-pulsed neutron source.

  12. Towards spark-proof gaseous pixel detectors

    Science.gov (United States)

    Tsigaridas, S.; Beuzekom, M. v.; Chan, H. W.; Graaf, H. v. d.; Hartjes, F.; Heijhoff, K.; Hessey, N. P.; Prodanovic, V.

    2016-11-01

    The micro-pattern gaseous pixel detector, is a promising technology for imaging and particle tracking applications. It is a combination of a gas layer acting as detection medium and a CMOS pixelated readout-chip. As a prevention against discharges we deposit a protection layer on the chip and then integrate on top a micromegas-like amplification structure. With this technology we are able to reconstruct 3D track segments of particles passing through the gas thanks to the functionality of the chip. We have turned a Timepix3 chip into a gaseous pixel detector and tested it at the SPS at Cern. The preliminary results are promising and within the expectations. However, the spark protection layer needs further improvement to make reliable detectors. For this reason, we have created a setup for spark-testing. We present the first results obtained from the lab-measurements along with preliminary results from the testbeam.

  13. Per-Pixel Lighting Data Analysis

    Energy Technology Data Exchange (ETDEWEB)

    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).

  14. Performance of active edge pixel sensors

    Science.gov (United States)

    Bomben, M.; Ducourthial, A.; Bagolini, A.; Boscardin, M.; Bosisio, L.; Calderini, G.; D'Eramo, L.; Giacomini, G.; Marchiori, G.; Zorzi, N.; Rummler, A.; Weingarten, J.

    2017-05-01

    To cope with the High Luminosity LHC harsh conditions, the ATLAS inner tracker has to be upgraded to meet requirements in terms of radiation hardness, pile up and geometrical acceptance. The active edge technology allows to reduce the insensitive area at the border of the sensor thanks to an ion etched trench which avoids the crystal damage produced by the standard mechanical dicing process. Thin planar n-on-p pixel sensors with active edge have been designed and produced by LPNHE and FBK foundry. Two detector module prototypes, consisting of pixel sensors connected to FE-I4B readout chips, have been tested with beams at CERN and DESY. In this paper the performance of these modules are reported. In particular the lateral extension of the detection volume, beyond the pixel region, is investigated and the results show high hit efficiency also at the detector edge, even in presence of guard rings.

  15. 320 x 240 uncooled IRFPA with pixel wise thin film vacuum packaging

    Science.gov (United States)

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

    2012-10-01

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

  16. First prototypes of two-tier avalanche pixel sensors for particle detection

    Science.gov (United States)

    Pancheri, L.; Brogi, P.; Collazuol, G.; Dalla Betta, G.-F.; Ficorella, A.; Marrocchesi, P. S.; Morsani, F.; Ratti, L.; Savoy-Navarro, A.

    2017-02-01

    In this paper, we present the implementation and preliminary evaluation of a new type of silicon sensor for charged particle detection operated in Geiger-mode. The proposed device, formed by two vertically-aligned pixel arrays, exploits the coincidence between two simultaneous avalanche events to discriminate between particle-triggered detections and dark counts. A proof-of-concept two-layer sensor with per-pixel coincidence circuits was designed and fabricated in a 150 nm CMOS process and vertically integrated through bump bonding. The sensor includes a 48×16 pixel array with 50 μ m × 75 μ m pixels. This work describes the sensor architecture and reports a selection of results from the characterization of the avalanche detectors in the two layers. Detectors with an active area of 43 × 45 μ m2 have a median dark count rate of 3 kHz at 3.3 V excess bias and a breakdown voltage non-uniformity lower than 20 mV.

  17. Detection of ultra-high energy cosmic ray showers with a single-pixel fluorescence telescope

    CERN Document Server

    Fujii, T; Bertaina, M; Casolino, M; Dawson, B; Horvath, P; Hrabovsky, M; Jiang, J; Mandat, D; Matalon, A; Matthews, J N; Motloch, P; Palatka, M; Pech, M; Privitera, P; Schovanek, P; Takizawa, Y; Thomas, S B; Travnicek, P; Yamazaki, K

    2015-01-01

    We present a concept for large-area, low-cost detection of ultra-high energy cosmic rays (UHECRs) with a Fluorescence detector Array of Single-pixel Tele- scopes (FAST), addressing the requirements for the next generation of UHECR experiments. In the FAST design, a large field of view is covered by a few pixels at the focal plane of a mirror or Fresnel lens. We report first results of a FAST prototype installed at the Telescope Array site, consisting of a single 200 mm photomultiplier tube at the focal plane of a 1 m2 Fresnel lens system taken from the prototype of the JEM-EUSO experiment. The FAST prototype took data for 19 nights, demonstrating remarkable operational stability. We detected laser shots at distances of several kilometres as well as 16 highly significant UHECR shower candidates.

  18. CMOS Pixel Spectroscopic Circuits for Cd(ZnTe Gamma Ray Imagers

    Directory of Open Access Journals (Sweden)

    Hatzistratis D.

    2016-01-01

    Full Text Available A family of 2-D pixel CMOS ASICs have been developed to be used as readout electronics of gamma ray imaging instruments based on hybrid pixel sensor arrays. One element of the sensor array consists of a pixilated single crystal of CdTe or CdZnTe semiconductor bump bonded to the CMOS electronic circuit. The first member of the family can process single photon signals which deliver up to 4fCb charge, while the two other can process signals up to 36fCb. A unique readout mode and the simultaneous extraction of energy and time tagging information of the converted photons differentiate the members of this family from other existing CMOS readout circuits.

  19. Thin hybrid pixel assembly with backside compensation layer on ROIC

    Science.gov (United States)

    Bates, R.; Buttar, C.; McMullen, T.; Cunningham, L.; Ashby, J.; Doherty, F.; Gray, C.; Pares, G.; Vignoud, L.; Kholti, B.; Vahanen, S.

    2017-01-01

    The entire ATLAS inner tracking system will be replaced for operation at the HL-LHC . This will include a significantly larger pixel detector of approximately 15 m2. For this project, it is critical to reduce the mass of the hybrid pixel modules and this requires thinning both the sensor and readout chips to about 150 micrometres each. The thinning of the silicon chips leads to low bump yield for SnAg bumps due to bad co-planarity of the two chips at the solder reflow stage creating dead zones within the pixel array. In the case of the ATLAS FEI4 pixel readout chip thinned to 100 micrometres, the chip is concave, with the front side in compression, with a bow of +100 micrometres at room temperature which varies to a bow of -175 micrometres at the SnAg solder reflow temperature, caused by the CTE mismatch between the materials in the CMOS stack and the silicon substrate. A new wafer level process to address the issue of low bump yield be controlling the chip bow has been developed. A back-side dielectric and metal stack of SiN and Al:Si has been deposited on the readout chip wafer to dynamically compensate the stress of the front side stack. In keeping with a 3D process the materials used are compatible with Through Silicon Via (TSV) technology with a TSV last approach which is under development for this chip. It is demonstrated that the amplitude of the correction can be manipulated by the deposition conditions and thickness of the SiN/Al:Si stack. The bow magnitude over the temperature range for the best sample to date is reduced by almost a factor of 4 and the sign of the bow (shape of the die) remains constant. Further development of the backside deposition conditions is on-going with the target of close to zero bow at the solder reflow temperature and a minimal bow magnitude throughout the temperature range. Assemblies produced from FEI4 readout wafers thinned to 100 micrometres with the backside compensation layer have been made for the first time and

  20. Physics performance of the ATLAS pixel detector

    Science.gov (United States)

    Tsuno, S.

    2017-01-01

    In preparation for LHC Run-2 the ATLAS detector introduced a new pixel detector, the Insertable B-Layer (IBL). This detector is located between the beampipe and what was the innermost pixel layer. The tracking and vertex reconstruction are significantly improved and good performance is expected in high level objects such a b-quark jet tagging. This in turn, leads to better physics results. This note summarizes the impact of the IBL detector on physics results, especially focusing on the analyses using b-quark jets throughout 2016 summer physics program.

  1. Commissioning of the ATLAS pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    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. Physics performance of the ATLAS Pixel Detector

    CERN Document Server

    Tsuno, Soshi; The ATLAS collaboration

    2016-01-01

    One noticeable upgrade from Run-1 to Run-2 with ATLAS detector in proton-proton collisions at LHC is the introduction of the new pixel detector, IBL, located on the beam pipe as the extra innermost pixel layer. The tracking and vertex reconstruction are significantly improved and good performance is expected in high level object such a $b$-quark jet tagging, in turn, it leads the better physics results. This note summarizes what is the impact on the IBL detector to the physics results especially focusing on the analyses using the $b$-quark jets throughout 2016 summer physics program.

  3. Reading a GEM with a VLSI pixel ASIC used as a direct charge collecting anode

    CERN Document Server

    Bellazzini, R; Baldini, L; Bitti, F; Brez, A; Latronico, L; Massai, M M; Minuti, M; Omodei, N; Razzano, M; Sgro, C; Spandre, G; Costa, E; Soffitta, P

    2004-01-01

    In MicroPattern Gas Detectors (MPGD) when the pixel size is below 100 micron and the number of pixels is large (above 1000) it is virtually impossible to use the conventional PCB read-out approach to bring the signal charge from the individual pixel to the external electronics chain. For this reason a custom CMOS array of 2101 active pixels with 80 micron pitch, directly used as the charge collecting anode of a GEM amplifying structure, has been developed and built. Each charge collecting pad, hexagonally shaped, realized using the top metal layer of a deep submicron VLSI technology is individually connected to a full electronics chain (pre-amplifier, shaping-amplifier, sample and hold, multiplexer) which is built immediately below it by using the remaining five active layers. The GEM and the drift electrode window are assembled directly over the chip so the ASIC itself becomes the pixelized anode of a MicroPattern Gas Detector. With this approach, for the first time, gas detectors have reached the level of i...

  4. FE-I4, the new ATLAS pixel chip for upgraded LHC luminosities

    Energy Technology Data Exchange (ETDEWEB)

    Arutinov, David; Barbero, Marlon; Gronewald, Markus; Hemperek, Tomasz; Karagounis, Michael; Krueger, Hans; Kruth, Andre; Wermes, Norbert [Physikalisches Institut, Universitaet Bonn, Nussallee 12, D-53115 Bonn (Germany)

    2010-07-01

    The new ATLAS pixel chip FE-I4 is being developed for use in upgraded luminosity environments, in the framework of the Insertable B-Layer (IBL) project and the outer pixel layers of Super-LHC. FE-I4 is designed in a 130 nm CMOS technology and is based on an array of 80 x 336 pixels, each 50 x x250 {mu}m2 and consisting of analog and digital sections. The analog pixel section is designed for low power consumption. The digital architecture is based on a 4 pixel unit called region, which allows for a power-efficient, low recording inefficiency design, and provides a handle to the problem of timewalk. The chip periphery contains a digital control block, a command decoder, powering blocks, a data reformatting unit, an 8b10b coder and a clock multiplier unit, which handles data transmission up to 160 Mb/s for the IBL. Increased power consumption in the inner layers of ATLAS translates into more material for cooling and power routing, which degrades the tracking and the b-tagging quality. As a consequence the FE-I4 collaboration places severe constraints on the power consumption of all blocks. First full scale FE-I4 submission will occur beginning 2010.

  5. A Low-Noise CMOS Pixel Direct Charge Sensor, Topmetal-II-

    CERN Document Server

    An, Mangmang; Gao, Chaosong; Han, Mikyung; Ji, Rong; Li, Xiaoting; Mei, Yuan; Sun, Quan; Sun, Xiangming; Wang, Kai; Xiao, Le; Xu, Nu; Yang, Ping; Zhou, Wei

    2016-01-01

    We report the design and characterization of a CMOS pixel direct charge sensor, Topmetal-II-, fabricated in a standard 0.35um CMOS Integrated Circuit process. The sensor utilizes exposed metal patches on top of each pixel to directly collect charge. Each pixel contains a low-noise charge-sensitive preamplifier to establish the analog signal and a discriminator with tunable threshold to generate hits. The analog signal from each pixel is accessible through time-shared multiplexing over the entire array. Hits are read out digitally through a column-based priority logic structure. Tests show that the sensor achieved a <15e- analog noise and a 200e- minimum threshold for digital readout per pixel. The sensor is capable of detecting both electrons and ions drifting in gas. These characteristics enable its use as the charge readout device in future Time Projection Chambers without gaseous gain mechanism, which has unique advantages in low background and low rate-density experiments.

  6. A low-noise CMOS pixel direct charge sensor, Topmetal-II-

    Science.gov (United States)

    An, Mangmang; Chen, Chufeng; Gao, Chaosong; Han, Mikyung; Ji, Rong; Li, Xiaoting; Mei, Yuan; Sun, Quan; Sun, Xiangming; Wang, Kai; Xiao, Le; Yang, Ping; Zhou, Wei

    2016-02-01

    We report the design and characterization of a CMOS pixel direct charge sensor, Topmetal-II-, fabricated in a standard 0.35 μm CMOS Integrated Circuit process. The sensor utilizes exposed metal patches on top of each pixel to directly collect charge. Each pixel contains a low-noise charge-sensitive preamplifier to establish the analog signal and a discriminator with tunable threshold to generate hits. The analog signal from each pixel is accessible through time-shared multiplexing over the entire array. Hits are read out digitally through a column-based priority logic structure. Tests show that the sensor achieved a analog noise and a 200e- minimum threshold for digital readout per pixel. The sensor is capable of detecting both electrons and ions drifting in gas. These characteristics enable its use as the charge readout device in future Time Projection Chambers without gaseous gain mechanism, which has unique advantages in low background and low rate-density experiments.

  7. FE-I4, the New ATLAS Pixel Chip for Upgraded LHC Luminosities

    CERN Document Server

    "Barbero, M; The ATLAS collaboration

    2009-01-01

    The new ATLAS pixel chip FE-I4 is being developed for use in upgraded luminosity environments, in the framework of the Insertable B-Layer (IBL) project but also for the outer pixel layers of Super-LHC. FE-I4 is designed in a 130 nm technology and is based on an array of 80 by 336 pixels, each 50×250 μm2 and consisting of analog and digital sections. The analog pixel section is designed for low power consumption and compatibility to several sensor candidates. The digital architecture is based on a 4 pixel unit called region, which allows for a power-efficient, low recording inefficiency design, and provides an elegant solution to the problem of timewalk. The chip periphery contains a control block, powering blocks, a data reformatting unit, an asynchronous storage FIFO, an 8b10b coder and a clock multiplier unit, which handles data transmission up to 160 Mb/s for the IBL.

  8. Compact SPAD-Based Pixel Architectures for Time-Resolved Image Sensors.

    Science.gov (United States)

    Perenzoni, Matteo; Pancheri, Lucio; Stoppa, David

    2016-05-23

    This paper reviews the state of the art of single-photon avalanche diode (SPAD) image sensors for time-resolved imaging. The focus of the paper is on pixel architectures featuring small pixel size (20%) as a key enabling technology for the successful implementation of high spatial resolution SPAD-based image sensors. A summary of the main CMOS SPAD implementations, their characteristics and integration challenges, is provided from the perspective of targeting large pixel arrays, where one of the key drivers is the spatial uniformity. The main analog techniques aimed at time-gated photon counting and photon timestamping suitable for compact and low-power pixels are critically discussed. The main features of these solutions are the adoption of analog counting techniques and time-to-analog conversion, in NMOS-only pixels. Reliable quantum-limited single-photon counting, self-referenced analog-to-digital conversion, time gating down to 0.75 ns and timestamping with 368 ps jitter are achieved.

  9. Compact SPAD-Based Pixel Architectures for Time-Resolved Image Sensors

    Directory of Open Access Journals (Sweden)

    Matteo Perenzoni

    2016-05-01

    Full Text Available This paper reviews the state of the art of single-photon avalanche diode (SPAD image sensors for time-resolved imaging. The focus of the paper is on pixel architectures featuring small pixel size (<25 μm and high fill factor (>20% as a key enabling technology for the successful implementation of high spatial resolution SPAD-based image sensors. A summary of the main CMOS SPAD implementations, their characteristics and integration challenges, is provided from the perspective of targeting large pixel arrays, where one of the key drivers is the spatial uniformity. The main analog techniques aimed at time-gated photon counting and photon timestamping suitable for compact and low-power pixels are critically discussed. The main features of these solutions are the adoption of analog counting techniques and time-to-analog conversion, in NMOS-only pixels. Reliable quantum-limited single-photon counting, self-referenced analog-to-digital conversion, time gating down to 0.75 ns and timestamping with 368 ps jitter are achieved.

  10. Small pixel cross-talk MTF and its impact on MWIR sensor performance

    Science.gov (United States)

    Goss, Tristan M.; Willers, Cornelius J.

    2017-05-01

    As pixel sizes reduce in the development of modern High Definition (HD) Mid Wave Infrared (MWIR) detectors the interpixel cross-talk becomes increasingly difficult to regulate. The diffusion lengths required to achieve the quantum efficiency and sensitivity of MWIR detectors are typically longer than the pixel pitch dimension, and the probability of inter-pixel cross-talk increases as the pixel pitch/diffusion length fraction decreases. Inter-pixel cross-talk is most conveniently quantified by the focal plane array sampling Modulation Transfer Function (MTF). Cross-talk MTF will reduce the ideal sinc square pixel MTF that is commonly used when modelling sensor performance. However, cross-talk MTF data is not always readily available from detector suppliers, and since the origins of inter-pixel cross-talk are uniquely device and manufacturing process specific, no generic MTF models appear to satisfy the needs of the sensor designers and analysts. In this paper cross-talk MTF data has been collected from recent publications and the development for a generic cross-talk MTF model to fit this data is investigated. The resulting cross-talk MTF model is then included in a MWIR sensor model and the impact on sensor performance is evaluated in terms of the National Imagery Interoperability Rating Scale's (NIIRS) General Image Quality Equation (GIQE) metric for a range of fnumber/ detector pitch Fλ/d configurations and operating environments. By applying non-linear boost transfer functions in the signal processing chain, the contrast losses due to cross-talk may be compensated for. Boost transfer functions, however, also reduce the signal to noise ratio of the sensor. In this paper boost function limits are investigated and included in the sensor performance assessments.

  11. Implementation of pixel level digital TDI for scanning type LWIR FPAs

    Science.gov (United States)

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

    2014-07-01

    Implementation of a CMOS digital readout integrated circuit (DROIC) based on pixel level digital time delay integration (TDI) for scanning type LWIR focal plane arrays (FPAs) is presented. TDI is implemented on 8 pixels with over sampling rate of 3. Analog signal integrated on integration capacitor is converted to digital domain in pixel, and digital data is transferred to TDI summation counters, where contributions of 8 pixels are added. Output data is 16 bit, where 8 bits are allocated for most significant bits and 8 bits for least significant bits. Control block of the ROIC, which is responsible of generating timing diagram for switches controlling the pixels and summation counters, is realized with VerilogHDL. Summation counters and parallel-to-serial converter to convert 16 bit parallel output data to single bit output are also realized with Verilog HDL. Synthesized verilog netlists are placed&routed and combined with analog under-pixel part of the design. Quantization noise of analog-to-digital conversion is less than 500e-. Since analog signal is converted to digital domain in-pixel, inaccuracies due to analog signal routing over large chip area is eliminated. ROIC is fabricated with 0.18μm CMOS process and chip area is 10mm2. Post-layout simulation results of the implemented design are presented. ROIC is programmable through serial or parallel interface. Input referred noise of ROIC is less than 750 rms electron, while power consumption is less than 30mW. ROIC is designed to perform in cryogenic temperatures.

  12. Extending the dynamic range of silicon photomultipliers without increasing pixel count

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Kurtis F., E-mail: kurtis.johnson@cern.c [Department of Physics, Florida State University, Tallahassee, FL (United States)

    2010-09-21

    A silicon photomultiplier, sometimes called 'multipixel photon counter', which we here refer to as a 'SiPM', is a photo-sensitive device built from an avalanche photodiode array of pixels on a common silicon substrate, such that it can detect single photon events. The dimensions of a pixel may vary from 20 to 100 {mu}m and their density can be greater than 1000 per square millimeter. Each pixel in a SiPM operates in Geiger mode and is coupled to the output by a quenching resistor. Although each pixel operates in digital mode, the SiPM is an analog device because all the pixels are read in parallel, making it possible to generate signals within a dynamic range from a single photon to a large number of photons, ultimately limited by the number of pixels on the chip. In this note we describe a simple and general method of increasing the dynamic range of a SiPM beyond that one may naively assume from the shape of the cumulative distribution function of the SiPM response to the average number of photons per pixel. We show that by rendering the incoming flux of photons to be non-uniform in a prescribed manner, a significant increase in dynamic range is achievable. Such re-distribution of the incoming flux may be accomplished with simple, non-focusing lenses, prisms, interference films, mirrors or attenuating films. Almost any optically non-inert interceding device can increase the dynamic range of the SiPM.

  13. Low-energy CZT detector array for the ASIM mission

    DEFF Research Database (Denmark)

    Cenkeramaddi, Linga Reddy; Genov, Georgi; Kohfeldt, Anja

    2012-01-01

    In this article we introduce the low-energy CZT (CdZnTe) 16 384-pixel detector array on-board the Atmosphere Space Interaction Monitor (ASIM), funded by the European Space Agency. This detector is a part of the larger Modular X-and Gamma-ray sensor (MXGS). The CZT detector array is sensitive...

  14. Design and Optimization of Multi-Pixel Transition-Edge Sensors for X-Ray Astronomy Applications

    Science.gov (United States)

    Smith, Stephen J.; Adams, Joseph S.; Bandler, Simon R.; Chervenak, James A.; Datesman, Aaron Michael; Eckart, Megan E.; Ewin, Audrey J.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline A.; hide

    2017-01-01

    Multi-pixel transition-edge sensors (TESs), commonly referred to as 'hydras', are a type of position sensitive micro-calorimeter that enables very large format arrays to be designed without commensurate increase in the number of readout channels and associated wiring. In the hydra design, a single TES is coupled to discrete absorbers via varied thermal links. The links act as low pass thermal filters that are tuned to give a different characteristic pulse shape for x-ray photons absorbed in each of the hydra sub pixels. In this contribution we report on the experimental results from hydras consisting of up to 20 pixels per TES. We discuss the design trade-offs between energy resolution, position discrimination and number of pixels and investigate future design optimizations specifically targeted at meeting the readout technology considered for Lynx.

  15. CMOS image sensor with lateral electric field modulation pixels for fluorescence lifetime imaging with sub-nanosecond time response

    Science.gov (United States)

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

    2016-04-01

    This paper presents the design and implementation of a time-resolved CMOS image sensor with a high-speed lateral electric field modulation (LEFM) gating structure for time domain fluorescence lifetime measurement. Time-windowed signal charge can be transferred from a pinned photodiode (PPD) to a pinned storage diode (PSD) by turning on a pair of transfer gates, which are situated beside the channel. Unwanted signal charge can be drained from the PPD to the drain by turning on another pair of gates. The pixel array contains 512 (V) × 310 (H) pixels with 5.6 × 5.6 µm2 pixel size. The imager chip was fabricated using 0.11 µm CMOS image sensor process technology. The prototype sensor has a time response of 150 ps at 374 nm. The fill factor of the pixels is 5.6%. The usefulness of the prototype sensor is demonstrated for fluorescence lifetime imaging through simulation and measurement results.

  16. A stimulated Raman scattering imager using high-speed lateral electric field modulator and lock-in pixels amplifiers

    Science.gov (United States)

    Mars, Kamel; Guseul, Beak; Han, Sang Man; Takasawa, Taishi; Yasutomi, Keita; Kagawa, Keiichiro; Hashimoto, Mamoru; Kawahito, Shoji

    2014-03-01

    A high speed Lateral Electric Field Modulator (LEFM) and lock-in pixels amplifiers for stimulated Raman scattering (SRS)imager is presented. Since the generated signal from the SRS process is very small compared to the offset signal, a technique suitable for extracting and amplifying the SRS signal is needed. The offset can be canceled by tuning the phase delay between the demodulated pixel output signal and the sampling clock. The small SRS signal in large offset is amplified by the differential integration. The proposed technique has been investigated with an implementation of 64x8 pixels array using a pinned photodiode LEFM an lock-in pixels amplifiers. Very small signal can be extracted from large offset signal. A ratio of the detected small SRS to offset signal of less 10-5 is achieved.

  17. Pixel-level tunable liquid crystal lenses for auto-stereoscopic display

    Science.gov (United States)

    Li, Kun; Robertson, Brian; Pivnenko, Mike; Chu, Daping; Zhou, Jiong; Yao, Jun

    2014-02-01

    Mobile video and gaming are now widely used, and delivery of a glass-free 3D experience is of both research and development interest. The key drawbacks of a conventional 3D display based on a static lenticular lenslet array and parallax barriers are low resolution, limited viewing angle and reduced brightness, mainly because of the need of multiple-pixels for each object point. This study describes the concept and performance of pixel-level cylindrical liquid crystal (LC) lenses, which are designed to steer light to the left and right eye sequentially to form stereo parallax. The width of the LC lenses can be as small as 20-30 μm, so that the associated auto-stereoscopic display will have the same resolution as the 2D display panel in use. Such a thin sheet of tunable LC lens array can be applied directly on existing mobile displays, and can deliver 3D viewing experience while maintaining 2D viewing capability. Transparent electrodes were laser patterned to achieve the single pixel lens resolution, and a high birefringent LC material was used to realise a large diffraction angle for a wide field of view. Simulation was carried out to model the intensity profile at the viewing plane and optimise the lens array based on the measured LC phase profile. The measured viewing angle and intensity profile were compared with the simulation results.

  18. Pixels simultaneous detection probabilities and spatial resolution determination of pixelized detectors by means of correlation measurements

    CERN Document Server

    Grabskii, V

    2007-01-01

    A novel method to estimate the pixels simultaneous detection probability and the spatial resolution of pixelized detectors is proposed, which is based on the determination of the statistical correlations between detector neighbor pixels. The correlations are determined by means of noise variance measurement for a isolated pixels and the difference between neighbor pixels. The method is validated using images from the two different GE Senographe 2000D mammographic units. The pixelized detector has been irradiated using x-rays along its entire surface. It is shown that the pixel simultaneous detection probabilities can be estimated within accuracy 0.001 - 0.003, where the systematic error is estimated to be smaller than 0.005. The presampled two-dimensional point-spread function (PSF0) is determined using a single Gaussian and a sum of two Gaussian approximations. The obtained results for the presampled PSF0 show that the single Gaussian approximation is not appropriate, and the sum of two Gaussian approximatio...

  19. From Hybrid to CMOS Pixels ... a possibility for LHC's pixel future?

    CERN Document Server

    Wermes, Norbert

    2015-01-01

    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 t...

  20. Planar pixel sensors in commercial CMOS technologies

    Energy Technology Data Exchange (ETDEWEB)

    Gonella, Laura; Hemperek, Tomasz; Huegging, Fabian; Krueger, Hans; Wermes, Norbert [Physikalisches Institut der Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany); Macchiolo, Anna [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany)

    2015-07-01

    For the upgrade of the ATLAS experiment at the high luminosity LHC, an all-silicon tracker is foreseen to cope with the increased rate and radiation levels. Pixel and strip detectors will have to cover an area of up to 200m2. To produce modules in high number at reduced costs, new sensor and bonding technologies have to be investigated. Commercial CMOS technologies on high resistive substrates can provide significant advantages in this direction. They offer cost effective, large volume sensor production. In addition to this, production is done on 8'' wafers allowing wafer-to-wafer bonding to the electronics, an interconnection technology substantially cheaper than the bump bonding process used for hybrid pixel detectors at the LHC. Both active and passive n-in-p pixel sensor prototypes have been submitted in a 150 nm CMOS technology on a 2kΩ cm substrate. The passive sensor design will be used to characterize sensor properties and to investigate wafer-to-wafer bonding technologies. This first prototype is made of a matrix of 36 x 16 pixels of size compatible with the FE-I4 readout chip (i.e. 50 μm x 250 μm). Results from lab characterization of this first submission are shown together with TCAD simulations. Work towards a full size FE-I4 sensor for wafer-to-wafer bonding is discussed.

  1. Sensor development for the CMS pixel detector

    CERN Document Server

    Bölla, G; Horisberger, R P; Kaufmann, R; Rohe, T; Roy, A

    2002-01-01

    The CMS experiment which is currently under construction at the Large Hadron Collider (LHC) at CERN (Geneva, Switzerland) will contain a pixel detector which provides in its final configuration three space points per track close to the interaction point of the colliding beams. Because of the harsh radiation environment of the LHC, the technical realization of the pixel detector is extremely challenging. The readout chip as the most damageable part of the system is believed to survive a particle fluence of 6x10 sup 1 sup 4 n sub e sub q /cm sup 2 (All fluences are normalized to 1 MeV neutrons and therefore all components of the hybrid pixel detector have to perform well up to at least this fluence. As this requires a partially depleted operation of the silicon sensors after irradiation-induced type inversion of the substrate, an ''n in n'' concept has been chosen. In order to perform IV-tests on wafer level and to hold accidentally unconnected pixels close to ground potential, a resistive path between the pixe...

  2. What's A Pixel Particle Sensor Chip?

    CERN Multimedia

    2008-01-01

    ATLAS particle physics experiment aided with collaboration ON Semiconductor was recently honored by the European Council for Nuclear Research (CERN), with an Industrial Award recognizing the company's contribution in supplying complex "Pixel Particle Sensor" chips for use in CERN's ATLAS particle physics experiment.

  3. Dense Iterative Contextual Pixel Classification using Kriging

    DEFF Research Database (Denmark)

    Ganz, Melanie; Loog, Marco; Brandt, Sami

    2009-01-01

    have been proposed to this end, e.g., iterative contextual pixel classification, iterated conditional modes, and other approaches related to Markov random fields. A problem of these methods, however, is their computational complexity, especially when dealing with high-resolution images in which...

  4. CMS has a heart of pixels

    CERN Multimedia

    2003-01-01

    At the core of CMS, particles will come into contact with tiny detector components, known as pixels, which are almost invisible to the naked eye. With these elementary cells measuring a mere 150 microns (or about 1/10 of a millimetre) along each side, a real technological leap has been made.

  5. ATLAS Pixel Group - Photo Gallery from Irradiation

    CERN Multimedia

    2001-01-01

    Photos 1,2,3,4,5,6,7 - Photos taken before irradiation of Pixel Test Analog Chip and Pmbars (April 2000) Photos 8,9,10,11 - Irradiation of VDC chips (May 2000) Photos 12, 13 - Irradiation of Passive Components (June 2000) Photos 14,15, 16 - Irradiation of Marebo Chip (November 1999)

  6. Performance of active edge pixel sensors

    CERN Document Server

    Bomben, Marco; Bagolini, Alvise; Boscardin, Maurizio; Bosisio, Luciano; Calderini, Giovanni; D'Eramo, Louis; Giacomini, Gabriele; Marchiori, Giovanni; Zorzi, Nicola; Rummler, Andre; Weingarten, Jens

    2017-01-01

    this paper the performance of these modules are reported. In particular the lateral extension of the detection volume, beyond the pixel region, is investigated and the results show high hit efficiency also at the detector edge, even in presence of guard rings.

  7. Dynamic holography using pixelated light modulators.

    Science.gov (United States)

    Zwick, Susanne; Haist, Tobias; Warber, Michael; Osten, Wolfgang

    2010-09-01

    Dynamic holography using spatial light modulators is a very flexible technique that offers various new applications compared to static holography. We give an overview on the technical background of dynamic holography focusing on pixelated spatial light modulators and their technical restrictions, and we present a selection of the numerous applications of dynamic holography.

  8. 6 Mcps photon-counting X-ray computed tomography system using a 25 mm/s-scan linear LSO-MPPC detector and its application to gadolinium imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Eiichi, E-mail: dresato@iwate-med.ac.jp [Department of Physics, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694 (Japan); Oda, Yasuyuki [Department of Physics, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694 (Japan); Abudurexiti, Abulajiang [Faculty of Software and Information Science, Iwate Prefectural University, 152-52 Sugo, Takizawa, Iwate 020-0193 (Japan); Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya [The 3rd Department of Surgery, Toho University School of Medicine, 2-17-6 Ohashi, Meguro-ku, Tokyo, Iwate 153-8515 (Japan); Sugimura, Shigeaki [Tokyo Denpa Co. Ltd., 82-5 Ueno, Ichinohe, Iwate 028-5321 (Japan); Endo, Haruyuki [Iwate Industrial Research Institute, 3-35-2 Shinden, Iioka, Morioka, Iwate 020-0852 (Japan); Sato, Shigehiro [Department of Microbiology, School of Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate 020-0023 (Japan); Ogawa, Akira [Department of Neurosurgery, School of Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate 020-0023 (Japan); Onagawa, Jun [Department of Electronics, Faculty of Engineering, Tohoku Gakuin University, 1-13-1 Chuo, Tagajo, Miyagi 985-8537 (Japan)

    2011-12-15

    6 Mcps photon counting was carried out using a detector consisting of a 1.0 mm-thick LSO [Lu{sub 2}(SiO{sub 4})O] single-crystal scintillator and an MPPC (multipixel photon counter) module in an X-ray computed tomography (CT) system. The maximum count rate was 6 Mcps (mega counts per second) at a tube voltage of 100 kV and a tube current of 0.91 mA. Next, a photon-counting X-ray CT system consists of an X-ray generator, a turntable, a scan stage, a two-stage controller, the LSO-MPPC detector, a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan with a scan velocity of 25 mm/s. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The exposure time for obtaining a tomogram was 600 s at a scan step of 0.5 mm and a rotation step of 1.0{sup o}, and photon-counting CT was accomplished using gadolinium-based contrast media. - Highlights: > 6 Mcps photon counting X-ray CT performed by repeated linear scans and rotations of an object. > Detector consists of an LSO scintillator and an MPPC (multipixel photon counter) module. > Projection curves of the object obtained by the linear scan with a velocity of 25 mm/s. > Exposure time was 600 s. CT was carried out using gadolinium-based contrast media.

  9. A kilo-pixel imaging system for future space based far-infrared observatories using microwave kinetic inductance detectors

    Science.gov (United States)

    Baselmans, J. J. A.; Bueno, J.; Yates, S. J. C.; Yurduseven, O.; Llombart, N.; Karatsu, K.; Baryshev, A. M.; Ferrari, L.; Endo, A.; Thoen, D. J.; de Visser, P. J.; Janssen, R. M. J.; Murugesan, V.; Driessen, E. F. C.; Coiffard, G.; Martin-Pintado, J.; Hargrave, P.; Griffin, M.

    2017-05-01

    Aims: Future astrophysics and cosmic microwave background space missions operating in the far-infrared to millimetre part of the spectrum will require very large arrays of ultra-sensitive detectors in combination with high multiplexing factors and efficient low-noise and low-power readout systems. We have developed a demonstrator system suitable for such applications. Methods: The system combines a 961 pixel imaging array based upon Microwave Kinetic Inductance Detectors (MKIDs) with a readout system capable of reading out all pixels simultaneously with only one readout cable pair and a single cryogenic amplifier. We evaluate, in a representative environment, the system performance in terms of sensitivity, dynamic range, optical efficiency, cosmic ray rejection, pixel-pixel crosstalk and overall yield at an observation centre frequency of 850 GHz and 20% fractional bandwidth. Results: The overall system has an excellent sensitivity, with an average detector sensitivity =3×10-19 WHz measured using a thermal calibration source. At a loading power per pixel of 50 fW we demonstrate white, photon noise limited detector noise down to 300 mHz. The dynamic range would allow the detection of 1 Jy bright sources within the field of view without tuning the readout of the detectors. The expected dead time due to cosmic ray interactions, when operated in an L2 or a similar far-Earth orbit, is found to be <4%. Additionally, the achieved pixel yield is 83% and the crosstalk between the pixels is <-30 dB. Conclusions: This demonstrates that MKID technology can provide multiplexing ratios on the order of a 1000 with state-of-the-art single pixel performance, and that the technology is now mature enough to be considered for future space based observatories and experiments.

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

    Science.gov (United States)

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

    2013-05-21

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

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

    Science.gov (United States)

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

    2013-10-01

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

  12. Optical phased-array ladar.

    Science.gov (United States)

    Montoya, Juan; Sanchez-Rubio, Antonio; Hatch, Robert; Payson, Harold

    2014-11-01

    We demonstrate a ladar with 0.5 m class range resolution obtained by integrating a continuous-wave optical phased-array transmitter with a Geiger-mode avalanche photodiode receiver array. In contrast with conventional ladar systems, an array of continuous-wave sources is used to effectively pulse illuminate a target by electro-optically steering far-field fringes. From the reference frame of a point in the far field, a steered fringe appears as a pulse. Range information is thus obtained by measuring the arrival time of a pulse return from a target to a receiver pixel. This ladar system offers a number of benefits, including broad spectral coverage, high efficiency, small size, power scalability, and versatility.

  13. The effect of activity outside the field of view on image quality for a 3D LSO-based whole body PET/CT scanner.

    Science.gov (United States)

    Matheoud, R; Secco, C; Della Monica, P; Leva, L; Sacchetti, G; Inglese, E; Brambilla, M

    2009-10-07

    The purpose of this study was to quantify the influence of outside field of view (FOV) activity concentration (A(c)(,out)) on the noise equivalent count rate (NECR), scatter fraction (SF) and image quality of a 3D LSO whole-body PET/CT scanner. The contrast-to-noise ratio (CNR) was the figure of merit used to characterize the image quality of PET scans. A modified International Electrotechnical Commission (IEC) phantom was used to obtain SF and counting rates similar to those found in average patients. A scatter phantom was positioned at the end of the modified IEC phantom to simulate an activity that extends beyond the scanner. The modified IEC phantom was filled with (18)F (11 kBq mL(-1)) and the spherical targets, with internal diameter (ID) ranging from 10 to 37 mm, had a target-to-background ratio of 10. PET images were acquired with background activity concentrations into the FOV (A(c)(,bkg)) about 11, 9.2, 6.6, 5.2 and 3.5 kBq mL(-1). The emission scan duration (ESD) was set to 1, 2, 3 and 4 min. The tube inside the scatter phantom was filled with activities to provide A(c)(,out) in the whole scatter phantom of zero, half, unity, twofold and fourfold the one of the modified IEC phantom. Plots of CNR versus the various parameters are provided. Multiple linear regression was employed to study the effects of A(c)(,out) on CNR, adjusted for the presence of variables (sphere ID, A(c)(,bkg) and ESD) related to CNR. The presence of outside FOV activity at the same concentration as the one inside the FOV reduces peak NECR of 30%. The increase in SF is marginal (1.2%). CNR diminishes significantly with increasing outside FOV activity, in the range explored. ESD and A(c)(,out) have a similar weight in accounting for CNR variance. Thus, an experimental law that adjusts the scan duration to the outside FOV activity can be devised. Recovery of CNR loss due to an elevated A(c)(,out) activity seems feasible by modulating the ESD in individual bed positions according to A(c)(,out).

  14. 3 mega-pixel InSb detector with 10μm pitch

    Science.gov (United States)

    Gershon, G.; Albo, A.; Eylon, M.; Cohen, O.; Calahorra, Z.; Brumer, M.; Nitzani, M.; Avnon, E.; Aghion, Y.; Kogan, I.; Ilan, E.; Shkedy, L.

    2013-06-01

    SCD has developed a new 1920x1536 / 10 μm digital Infrared detector for the MWIR window named Blackbird. The Blackbird detector features a Focal Plane Array (FPA) that incorporates two technological building blocks developed over the past few years. The first one is a 10 μm InSb pixel based on the matured planar technology. The second building block is an innovative 10 μm ReadOut Integrated Circuit (ROIC) pixel. The InSb and the ROIC arrays are connected using Flip-Chip technology by means of indium bumps. The digital ROIC consists a matrix of 1920x1536 pixels and has an analog to digital (A/D) converter per-channel (total of 1920x2 A/Ds). It allows for full frame readout at a high frame rate of up to 120 Hz. Such an on-chip A/D conversion eliminates the need for several A/D converters with fairly high power consumption at the system level. The ROIC power consumption at maximum bandwidth is less than 400 mW. It features a wide range of pixel-level functionality such as several conversion gain options and a 2x2 pixel binning. The ROIC design makes use of the advanced and matured CMOS technology, 0.18 μm, which allows for high functionality and relatively low power consumption. The FPA is mounted on a Cold-Finger by a specially designed ceramic substrate. The whole assembly is housed in a stiffened Dewar that withstands harsh environmental conditions while minimizing the environment heat load contribution to the heat load of the detector. The design enables a 3-megapixel detector with overall low size, weight, and power (SWaP) with respect to comparable large format detectors. In this work we present in detail the characteristic performance of the new Blackbird detector.

  15. PixelSNE: Visualizing Fast with Just Enough Precision via Pixel-Aligned Stochastic Neighbor Embedding

    OpenAIRE

    Kim, Minjeong; Choi, Minsuk; Lee, Sunwoong; Tang, Jian; Park, Haesun; Choo, Jaegul

    2016-01-01

    Embedding and visualizing large-scale high-dimensional data in a two-dimensional space is an important problem since such visualization can reveal deep insights out of complex data. Most of the existing embedding approaches, however, run on an excessively high precision, ignoring the fact that at the end, embedding outputs are converted into coarse-grained discrete pixel coordinates in a screen space. Motivated by such an observation and directly considering pixel coordinates in an embedding ...

  16. Upgrade of ATLAS ITk Pixel Detector

    CERN Document Server

    Huegging, Fabian; The ATLAS collaboration

    2017-01-01

    The high luminosity upgrade of the LHC (HL-LHC) in 2026 will provide new challenges to the ATLAS tracker. The current inner detector will be replaced with an entirely-silicon inner tracker (ITk) which will consist of a five barrel layer Pixel detector surrounded by a four barrel layer Strip detector. The expected high radiation levels are requiring the development of upgraded silicon sensors as well as new a front-end chip. The dense tracking environment will require finer granularity detectors and low mass global and local support structures. The data rates will require new technologies for high bandwidth data transmission and handling. The current status of the ITk ATLAS Pixel detector developments as well as different layout options will be reviewed.

  17. Towards third generation pixel readout chips

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Sciveres, M., E-mail: mgarcia-sciveres@lbl.gov; Mekkaoui, A.; Ganani, D.

    2013-12-11

    We present concepts and prototyping results towards a third generation pixel readout chip. We consider the 130 nm feature size FE-I4 chip, in production for the ATLAS IBL upgrade, to be a second generation chip. A third generation chip would have to go significantly further. A possible direction is to make the IC design generic so that different experiments can configure it to meet significantly different requirements, without the need for everybody to develop their own ASIC from the ground up. In terms of target technology, a demonstrator 500-pixel matrix containing analog front ends only (no complex functionality), was designed and fabricated in 65 nm CMOS and irradiated with protons in December 2011 and May 2012.

  18. Monolithic pixel detectors for high energy physics

    CERN Document Server

    Snoeys, W

    2013-01-01

    Monolithic pixel detectors integrating sensor matrix and readout in one piece of silicon have revolutionized imaging for consumer applications, but despite years of research they have not yet been widely adopted for high energy physics. Two major requirements for this application, radiation tolerance and low power consumption, require charge collection by drift for the most extreme radiation levels and an optimization of the collected signal charge over input capacitance ratio ( Q / C ). It is shown that monolithic detectors can achieve Q / C for low analog power consumption and even carryout the promise to practically eliminate analog power consumption, but combining suf fi cient Q / C , collection by drift, and integration of readout circuitry within the pixel remains a challenge. An overview is given of different approaches to address this challenge, with possible advantages and disadvantages.

  19. Noise in a CMOS digital pixel sensor

    Institute of Scientific and Technical Information of China (English)

    Zhang Chi; Yao Suying; Xu Jiangtao

    2011-01-01

    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.

  20. ATLAS Pixel IBL: Stave Quality Assurance

    CERN Document Server

    The ATLAS collaboration

    2014-01-01

    For Run 2 of the LHC a fourth innermost Pixel Detector layer on a smaller radius beam pipe has been installed in the ATLAS Detector to add redundancy against radiation damage of the current Pixel Detector and to ensure a high quality tracking and b-tagging performance of the Inner Detector over the coming years until the High Luminosity Upgrade. State of the art components have been produced and assembled onto support structures known as staves over the last two years. In total, 20 staves have been built and qualified in a designated Quality Assurance setup at CERN of which 14 have been integrated onto the beam pipe. Results from the testing are presented.

  1. Edge effects in a small pixel CdTe for X-ray imaging

    Science.gov (United States)

    Duarte, D. D.; Bell, S. J.; Lipp, J.; Schneider, A.; Seller, P.; Veale, M. C.; Wilson, M. D.; Baker, M. A.; Sellin, P. J.; Kachkanov, V.; Sawhney, K. J. S.

    2013-10-01

    Large area detectors capable of operating with high detection efficiency at energies above 30 keV are required in many contemporary X-ray imaging applications. The properties of high Z compound semiconductors, such as CdTe, make them ideally suitable to these applications. The STFC Rutherford Appleton Laboratory has developed a small pixel CdTe detector with 80 × 80 pixels on a 250 μm pitch. Historically, these detectors have included a 200 μm wide guard band around the pixelated anode to reduce the effect of defects in the crystal edge. The latest version of the detector ASIC is capable of four-side butting that allows the tiling of N × N flat panel arrays. To limit the dead space between modules to the width of one pixel, edgeless detector geometries have been developed where the active volume of the detector extends to the physical edge of the crystal. The spectroscopic performance of an edgeless CdTe detector bump bonded to the HEXITEC ASIC was tested with sealed radiation sources and compared with a monochromatic X-ray micro-beam mapping measurements made at the Diamond Light Source, U.K. The average energy resolution at 59.54 keV of bulk and edge pixels was 1.23 keV and 1.58 keV, respectively. 87% of the edge pixels present fully spectroscopic performance demonstrating that edgeless CdTe detectors are a promising technology for the production of large panel radiation detectors for X-ray imaging.

  2. The Belle II DEPFET pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Moser, Hans-Günther, E-mail: moser@mpp.mpg.de

    2016-09-21

    The Belle II experiment at KEK (Tsukuba, Japan) will explore heavy flavour physics (B, charm and tau) at the starting of 2018 with unprecedented precision. Charged particles are tracked by a two-layer DEPFET pixel device (PXD), a four-layer silicon strip detector (SVD) and the central drift chamber (CDC). The PXD will consist of two layers at radii of 14 mm and 22 mm with 8 and 12 ladders, respectively. The pixel sizes will vary, between 50 μm×(55–60) μm in the first layer and between 50 μm×(70–85) μm in the second layer, to optimize the charge sharing efficiency. These innermost layers have to cope with high background occupancy, high radiation and must have minimal material to reduce multiple scattering. These challenges are met using the DEPFET technology. Each pixel is a FET integrated on a fully depleted silicon bulk. The signal charge collected in the ‘internal gate’ modulates the FET current resulting in a first stage amplification and therefore very low noise. This allows very thin sensors (75 μm) reducing the overall material budget of the detector (0.21% X{sub 0}). Four fold multiplexing of the column parallel readout allows read out a full frame of the pixel matrix in only 20 μs while keeping the power consumption low enough for air cooling. Only the active electronics outside the detector acceptance has to be cooled actively with a two phase CO{sub 2} system. Furthermore the DEPFET technology offers the unique feature of an electronic shutter which allows the detector to operate efficiently in the continuous injection mode of superKEKB.

  3. Pixel Dynamics Analysis of Photospheric Spectral Data

    Science.gov (United States)

    2014-11-13

    corresponding Doppler blueshift (redshift) integrated over the pixel. Variations in the line width δλm may indicate variations in temperature or changes in...skewness of their absorption line redshift/ blueshift and asymmetry PFDs, as well as by the spatial average for each region. These three time-varying... blueshift PFD variance and skewness plots). These oscillations, associated with the AR regions exhibiting solar eruptions, occur with a period of ∼ 10

  4. Efficient segmentation by sparse pixel classification

    DEFF Research Database (Denmark)

    Dam, Erik B; Loog, Marco

    2008-01-01

    Segmentation methods based on pixel classification are powerful but often slow. We introduce two general algorithms, based on sparse classification, for optimizing the computation while still obtaining accurate segmentations. The computational costs of the algorithms are derived......, and they are demonstrated on real 3-D magnetic resonance imaging and 2-D radiograph data. We show that each algorithm is optimal for specific tasks, and that both algorithms allow a speedup of one or more orders of magnitude on typical segmentation tasks....

  5. The Belle II DEPFET pixel detector

    Science.gov (United States)

    Moser, Hans-Günther

    2016-09-01

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

  6. Electrical Characteristics of Silicon Pixel Sensors

    CERN Document Server

    Gorelov, I; Hoeferkamp, M; Mata-Bruni, V; Santistevan, G; Seidel, S C; Ciocio, A; Einsweiler, K F; Emes, J; Gilchriese, M G D; Joshi, A; Kleinfelder, S A; Marchesini, R; McCormack, F; Milgrome, O; Palaio, N; Pengg, F; Richardson, J; Zizka, G; Ackers, M; Comes, G; Fischer, P; Keil, M; Klasen, V; Kühl, T; Meuser, S; Ockenfels, W; Raith, B; Treis, J; Wermes, N; Gössling, C; Hügging, F G; Klaiber Lodewigs, Jonas M; Krasel, O; Wüstenfeld, J; Wunstorf, R; Barberis, D; Beccherle, R; Caso, Carlo; Cervetto, M; Darbo, G; Gagliardi, G; Gemme, C; Morettini, P; Netchaeva, P; Osculati, B; Rossi, L; Charles, E; Fasching, D; Blanquart, L; Breugnon, P; Calvet, D; Clemens, J-C; Delpierre, P A; Hallewell, G D; Laugier, D; Mouthuy, T; Rozanov, A; Valin, I; Andreazza, A; Caccia, M; Citterio, M; Lari, T; Meroni, C; Ragusa, F; Troncon, C; Vegni, G; Lutz, Gerhard; Richter, R H; Rohe, T; Boyd, GR; Skubic, P L; Sícho, P; Tomasek, L; Vrba, V; Holder, M; Ziolkowski, M; Cauz, D; Cobal-Grassmann, M; D'Auria, S; De Lotto, B; del Papa, C; Grassmann, H; Santi, L; Becks, K H; Lenzen, G; Linder, C

    2001-01-01

    Prototype sensors for the ATLAS silicon pixel detector have been electrically characterized. The current and voltage characteristics, charge collection efficiencies, and resolutions have been examined. Devices were fabricated on oxygenated and standard detector-grade silicon wafers. Results from prototypes which examine p-stop and standard and moderated p-spray isolation are presented for a variety of geometrical options. Some of the comparisons relate unirradiated sensors with those that have received fluences relevant to LHC operation.

  7. Production chain of CMS pixel modules

    CERN Document Server

    2006-01-01

    The pictures show the production chain of pixel modules for the CMS detector. Fig.1: overview of the assembly procedure. Fig.2: bump bonding with ReadOut Chip (ROC) connected to the sensor. Fig.3: glueing a raw module onto the baseplate strips. Fig.4: glueing of the High Density Interconnect (HDI) onto a raw module. Fig.5: pull test after heat reflow. Fig.6: wafer sensor processing, Indium evaporation.

  8. Performance of Large Format Transition Edge Sensor Microcalorimeter Arrays

    Science.gov (United States)

    Chervenak, J. A.; Adams, J. A.; Bandler, S. B.; Busch, S. E.; Eckart, M. E.; Ewin, A. E.; Finkbeiner, F. M.; Kilbourne, C. A.; Kelley, R. L.; Porst, J. P.; Porter, F. S.; Ray, C.; Sadleir, J. E.; Smith, S. J.; Wassell, E. J.

    2012-01-01

    We have produced a variety of superconducting transition edge sensor array designs for microcalorimetric detection of x-rays. Arrays are characterized with a time division SQUID multiplexer such that greater than 10 devices from an array can be measured in the same cooldown. Designs include kilo pixel scale arrays of relatively small sensors (-75 micron pitch) atop a thick metal heatsinking layer as well as arrays of membrane-isolated devices on 250 micron and up to 600 micron pitch. We discuss fabrication and performance of microstripline wiring at the small scales achieved to date. We also address fabrication issues with reduction of absorber contact area in small devices.

  9. Radiation hardness studies of silicon pixel detectors

    CERN Document Server

    Lari, T

    2006-01-01

    At the LHC silicon vertex detectors will be exposed to hadron fluences of the order of . In order to study the effects of radiation damage on the performances of the ATLAS Pixel Vertex Detector, several full-size detector modules were irradiated to a fluence of and tested in a beam at CERN. After irradiation only a modest degradation of the detector performances is observed. At the operating ATLAS bias voltage of 600 V the average signal is still 80% of the pre-irradiation value, the spatial resolution is and the detection efficiency is 98.2%. The LHC luminosity upgrade will increase the radiation hardness requirements by a factor of 10 and will require the development of new ultra-radiation hard vertex detectors. A detailed simulation of silicon pixel detectors irradiated to very high fluence is presented and used to study the possibility to use silicon pixel detectors at the LHC after the luminosity upgrade. The charge collection properties and the detector response were computed for different silicon mater...

  10. Baryon Acoustic Oscillations reconstruction with pixels

    CERN Document Server

    Obuljen, Andrej; Castorina, Emanuele; Viel, Matteo

    2016-01-01

    Gravitational non-linear evolution induces a shift in the position of the baryon acoustic oscillations (BAO) peak together with a damping and broadening of its shape that bias and degrades the accuracy with which the position of the peak can be determined. BAO reconstruction is a technique developed to undo part of the effect of non-linearities. We present a new reconstruction method that consists in displacing pixels instead of galaxies and whose implementation is easier than the standard reconstruction method. We show that our method is equivalent to the standard reconstruction technique in the limit where the number of pixels becomes very large. This method is particularly useful in surveys where individual galaxies are not resolved, as in 21cm intensity mapping observations. We validate our method by reconstructing mock pixelated maps, that we build from the distribution of matter and halos in real- and redshift-space, from a large set of numerical simulations. We find that our method is able to decrease ...

  11. ATLAS ITk and new pixel sensors technologies

    CERN Document Server

    Gaudiello, A

    2016-01-01

    During the 2023–2024 shutdown, the Large Hadron Collider (LHC) will be upgraded to reach an instantaneous luminosity up to 7×10$^{34}$ cm$^{−2}$s$^{−1}$. This upgrade of the accelerator is called High-Luminosity LHC (HL-LHC). The ATLAS detector will be changed to meet the challenges of HL-LHC: an average of 200 pile-up events in every bunch crossing, and an integrated luminosity of 3000 fb $^{−1}$ over ten years. The HL-LHC luminosity conditions are too extreme for the current silicon (pixel and strip) detectors and straw tube transition radiation tracker (TRT) of the current ATLAS tracking system. Therefore the ATLAS inner tracker is being completely rebuilt for data-taking and the new system is called Inner Tracker (ITk). During this upgrade the TRT will be removed in favor of an all-new all-silicon tracker composed only by strip and pixel detectors. An overview of new layouts in study will be reported and the new pixel sensor technologies in development will be explained.

  12. Readout Architecture for Hybrid Pixel Readout Chips

    CERN Document Server

    AUTHOR|(SzGeCERN)694170; Westerlund, Tomi; Wyllie, Ken

    The original contribution of this thesis to knowledge are novel digital readout architectures for hybrid pixel readout chips. The thesis presents asynchronous bus-based architecture, a data-node based column architecture and a network-based pixel matrix architecture for data transportation. It is shown that the data-node architecture achieves readout efficiency 99 % with half the output rate as a bus-based system. The network-based solution avoids ``broken'' columns due to some manufacturing errors, and it distributes internal data traffic more evenly across the pixel matrix than column-based architectures. An improvement of $>$ 10 % to the efficiency is achieved with uniform and non-uniform hit occupancies. Architectural design has been done using transaction level modeling ($TLM$) and sequential high-level design techniques for reducing the design and simulation time. It has been possible to simulate tens of column and full chip architectures using the high-level techniques. A decrease of $>$ 10 in run-time...

  13. Characterization of the CMS Pixel Detectors

    CERN Document Server

    Gu, Weihua

    2002-01-01

    In 2005 the Large Hadron Collider (LHC) will start the pp collisions at a high luminosity and at a center of mass energy of 14 TeV. The primary goal of the experimental programme is the search of the Higgs boson(s) and the supersymmetric particles. The programme is also proposed to detect a range of diverse signatures in order to provide guidance for future physics. The pixel detector system makes up the innermost part of the CMS experiment, which is one of the two general purpose detectors at the LHC. The main tasks of the system are vertex detection and flavor tagging. The high luminosity and the high particle multiplicity as well as the small bunch spacing at the LHC impose great challenges on the pixel detectors: radiation hardness of sensors and electronics, fast signal processing and a high granularity are the essential requirements. This thesis concentrates on the study of the suitability of two test stands, which are implemented to characterize the CMS pixel detectors: one is con-cerned with test puls...

  14. Characterization of the column-based priority logic readout of Topmetal-II‑ CMOS pixel direct charge sensor

    Science.gov (United States)

    An, M.; Zhang, W.; Xiao, L.; Gao, C.; Chen, C.; Han, M.; Huang, G.; Ji, R.; Li, X.; Liu, J.; Mei, Y.; Pei, H.; Sun, Q.; Sun, X.; Wang, K.; Yang, P.; Zhou, W.

    2017-03-01

    We present the detailed study of the digital readout of Topmetal-II- CMOS pixel direct charge sensor. Topmetal-II- is an integrated sensor with an array of 72×72 pixels each capable of directly collecting external charge through exposed metal electrodes in the topmost metal layer. In addition to the time-shared multiplexing readout of the analog output from Charge Sensitive Amplifiers in each pixel, hits are also generated through comparators in each pixel with individually adjustable thresholds. The hits are read out via a column-based priority logic structure, retaining both hit location and time information. The in-array column-based priority logic features with a full clock-less circuitry hence there is no continuously running clock distributed in the pixel and matrix logic. These characteristics enable its use as the charge readout device in future Time Projection Chambers without gaseous gain mechanism, which has unique advantages in low background and low rate-density experiments. We studied the detailed working behavior and performance of this readout, and demonstrated its functional validity and potential in imaging applications.

  15. Sky pixelization for the analysis of extended emission

    Science.gov (United States)

    Verkhodanov, O. V.; Doroshkevich, A. G.

    2013-08-01

    Spherical pixelization schemes are reviewed that allow analyzing extended emission and, in particular, the cosmic microwave background. Problems with implementing different schemes are considered. The nonhierarchical Gauss-Legendre sky pixelization (GLESP) approach is discussed in detail.

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

    Science.gov (United States)

    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.

  17. Mass test of AdvanSiD model ASD-NUV3S-P SiliconPMs for the Pixel Timing Counter of the MEG II experiment

    Science.gov (United States)

    Rossella, M.; Bariani, S.; Barnaba, O.; Cattaneo, P. W.; Cervi, T.; Menegolli, A.; Nardò, R.; Prata, M. C.; Romano, E.; Scagliotti, C.; Simonetta, M.; Vercellati, F.

    2017-02-01

    The MEG II Timing Counter will measure the positron time of arrival with a resolution of 30 ps relying on two arrays of scintillator pixels read out by 6144 Silicon Photomultipliers (SiPMs) from AdvanSiD. They must be characterized, measuring their breakdown voltage, to assure that the gains of the SiPMs of each pixel are as uniform as possible, to maximize the pixel resolution. To do this an automatic test system that can measure sequentially the parameters of 32 devices has been developed.

  18. 4T CMOS Active Pixel Sensors under Ionizing Radiation

    NARCIS (Netherlands)

    Tan, J.

    2013-01-01

    This thesis investigates the ionizing radiation effects on 4T pixels and the elementary in-pixel test devices with regard to the electrical performance and the optical performance. In addition to an analysis of the macroscopic pixel parameter degradation, the radiation-induced degradation mechanisms

  19. Preliminary test of an imaging probe for nuclear medicine using hybrid pixel detectors

    CERN Document Server

    Bertolucci, Ennio; Mettivier, G; Montesi, M C; Russo, P

    2002-01-01

    We are investigating the feasibility of an intraoperative imaging probe for lymphoscintigraphy with Tc-99m tracer, for sentinel node radioguided surgery, using the Medipix series of hybrid detectors coupled to a collimator. These detectors are pixelated semiconductor detectors bump-bonded to the Medipix1 photon counting read-out chip (64x64 pixel, 170 mu m pitch) or to the Medipix2 chip (256x256 pixel, 55 mu m pitch), developed by the European Medipix collaboration. The pixel detector we plan to use in the final version of the probe is a semi-insulating GaAs detector or a 1-2 mm thick CdZnTe detector. For the preliminary tests presented here, we used 300-mu m thick silicon detectors, hybridized via bump-bonding to the Medipix1 chip. We used a tungsten parallel-hole collimator (7 mm thick, matrix array of 64x64 100 mu m circular holes with 170 mu m pitch), and a 22, 60 and 122 keV point-like (1 mm diameter) radioactive sources, placed at various distances from the detector. These tests were conducted in order ...

  20. Matrix light and pixel light: optical system architecture and requirements to the light source

    Science.gov (United States)

    Spinger, Benno; Timinger, Andreas L.

    2015-09-01

    Modern Automotive headlamps enable improved functionality for more driving comfort and safety. Matrix or Pixel light headlamps are not restricted to either pure low beam functionality or pure high beam. Light in direction of oncoming traffic is selectively switched of, potential hazard can be marked via an isolated beam and the illumination on the road can even follow a bend. The optical architectures that enable these advanced functionalities are diverse. Electromechanical shutters and lens units moved by electric motors were the first ways to realize these systems. Switching multiple LED light sources is a more elegant and mechanically robust solution. While many basic functionalities can already be realized with a limited number of LEDs, an increasing number of pixels will lead to more driving comfort and better visibility. The required optical system needs not only to generate a desired beam distribution with a high angular dynamic, but also needs to guarantee minimal stray light and cross talk between the different pixels. The direct projection of the LED array via a lens is a simple but not very efficient optical system. We discuss different optical elements for pre-collimating the light with minimal cross talk and improved contrast between neighboring pixels. Depending on the selected optical system, we derive the basic light source requirements: luminance, surface area, contrast, flux and color homogeneity.

  1. Data concentrator with FPGA-based track reconstruction for the Belle II DEPFET pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Schnell, Michael; Dingfelder, Jochen; Marinas, Carlos [Physikalisches Institut, Universitaet Bonn (Germany)

    2013-07-01

    The innermost two layers of the Belle II vertex detector at the KEK facility in Tsukuba, Japan, will be covered by high-granularity DEPFET pixel sensors. The large number of pixels leads to a high data rate of around 60 Gbps, which has to be significantly reduced by the Data Acquisition System. For the data reduction the hit information of the surrounding Silicon strip Vertex Detector (SVD) is utilized to define so-called Regions of Interest (ROI). Only hit information of the pixels located inside these ROIs are saved. The ROIs for the Pixel Detector (PXD) are computed by reconstructing track segments from SVD data and back extrapolation to the PXD. A data reduction of up to a factor of 10 is intended to be achieved by this design. All the necessary processing stages, the receiving and multiplexing of the data from the SVD on 48 optical fibers, the track reconstruction and the definition of the ROIs, will be performed by the Data Concentrator. The planned hardware design is based on a distributed set of Advanced Mezzanine Cards (AMC) each equipped with a Field Programmable Gate Array (FPGA) chip and 4 optical transceivers. In this talk, the hardware and the FPGA-based tracking algorithm is introduced with some preliminary simulation results. In addition, the acquisition and pre-processing of the SVD data are discussed. The presentation concludes with an outlook on a distributed tracking design.

  2. \\title{Low-Cost Bump-Bonding Processes for High Energy Physics Pixel Detectors}

    CERN Document Server

    Caselle, Michele; Colombo, Fabio; Dierlamm, Alexander Hermann; Husemann, Ulrich; Kudella, Simon; Weber, M

    2015-01-01

    In the next generation of collider experiments detectors will be challenged by unprecedented particle fluxes. Thus large detector arrays of highly pixelated detectors with minimal dead area at reasonable costs are required. Bump-bonding of pixel detectors has been shown to be a major cost-driver. KIT is one of the production centers of the CMS barrel pixel detector for the Phase I Upgrade. In this contribution the SnPb bump-bonding process and the production yield is reported. In parallel to the production of the new CMS pixel detector, several alternatives to the expensive photolithography electroplating/electroless metal deposition technologies are developing. Recent progress and challenges faced in the development of bump-bonding technology based on gold-stud bonding by thin ($15\\,\\rm{\\mu m}$) gold wire is presented. This technique allows producing metal bumps with diameters down to $30\\,\\rm{\\mu m}$ without using photolithography processes, which are typically required to provide suitable under bu...

  3. Module production for the Phase 1 upgrade of the CMS forward pixel detector

    Science.gov (United States)

    Siado Castaneda, Joaquin

    2017-01-01

    For Run 2 the Large Hadron Collider will run at a much higher instantaneous luminosity, which requires an upgrade of the CMS pixel detector. The detector consists of rectangular silicon sensors, segmented into 100 μm by 150 μm pixels, bonded to readout chips, with one sensor and a 8x2 array of readout chips forming a module. Due to its high granularity and good spatial resolution, about 10 μm for a single hit, the pixel detector is used for track reconstruction, pileup mitigation, and b-quark tagging in many physics analyses. Being the innermost sub-detector of CMS it receives the most radiation damage, and therefore needs to be replaced most often. For the phase 1 upgrade an additional disk in the forward region and increased buffer space in the readout chip will improve the pixel performance by increasing efficiency and reducing fake rates. The University of Nebraska-Lincoln is one of the two sites where modules are being assembled. This talk features the steps of the assembly process as well as challenges encountered and overcome during production of over 500 modules. The CMS Collaboration.

  4. A high performance multi-tap CMOS lock-in pixel image sensor for biomedical applications

    Science.gov (United States)

    Seo, Min-Woong; Shirakawa, Yuya; Kagawa, Keiichiro; Yasutomi, Keita; Kawahito, Shoji

    2017-02-01

    We have developed and evaluated the large full well capacity (FWC) for wide signal detection range and low temporal noise for high sensitivity lock-in pixel CMOS image sensor (CIS) embedded with two storage-diodes (SDs). In addition, for fast charge transfer from photodiode (PD) to SDs, a lateral electric field charge modulator (LEFM) is used for the developed lock-in pixel. As a result, the time-resolved CIS achieves a very large FWC of approximately 7000e-, low temporal random noise of 1.17e-rms at 45fps with true correlated double sampling (CDS) operation, and fast intrinsic response less than 500ps at 635nm. The proposed imager has an effective pixel array of 128(H)×256(V) and a pixel size of 11.2×11.2μm2. The sensor chip is fabricated by a Dongbu HiTek 1P4M 0.11μm CIS process.

  5. Radiation tolerance of prototype BTeV pixel detector readout chips

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Amorphous silicon pixel layers with cesium iodide converters for medical radiography

    Energy Technology Data Exchange (ETDEWEB)

    Jing, T.; Cho, G. [Lawrence Berkeley Lab., CA (United States); Goodman, C.A. [Air Techniques, Inc., Hicksville, NY (United States)] [and others

    1993-11-01

    We describe the properties of evaporated layers of Cesium Iodide (Thallium activated) deposited on substrates that enable easy coupling to amorphous silicon pixel arrays. The CsI(Tl) layers range in thickness from 65 to 220{mu}m. We used the two-boat evaporator system to deposit CsI(Tl) layers. This system ensures the formation of the scintillator film with homogenous thallium concentration which is essential for optimizing the scintillation light emission efficiency. The Tl concentration was kept to 0.1--0.2 mole percent for the highest light output. Temperature annealing can affect the microstructure as well as light output of the CsI(Tl) film. 200--300C temperature annealing can increase the light output by a factor of two. The amorphous silicon pixel arrays are p-i-n diodes approximately l{mu}m thick with transparent electrodes to enable them to detect the scintillation light produced by X-rays incident on the CsI(Tl). Digital radiography requires a good spatial resolution. This is accomplished by making the detector pixel size less then 50{mu}m. The light emission from the CsI(Tl) is collimated by techniques involving the deposition process on pattered substrates. We have measured MTF of greater than 12 line pairs per mm at the 10% level.

  7. A new pixel level digital read out integrated circuits for ultraviolet imaging sensors

    Science.gov (United States)

    Xu, Bin; Lan, Tian-yi; Yuan, Yong-gang; Li, Xiang-yang

    2014-11-01

    The ultraviolet imaging sensors consist of two important parts: the array of detectors and the read out integrated circuits. Along with the demand for the fine resolution, large input dynamic range and high integration degree of the imaging sensors, the functions of read out integrated circuits are becoming more and more important. The on chip analog to digital conversion is the main directions of research on this area. In this paper, we presented a new digital read out integrated circuits for ultraviolet imaging sensors. The proposed circuits have an analog to digital converter in each pixel, which enable the parallel analog to digital conversion of the whole pixel array. The developed circuits have a 50um×50um pixel area with a 128×128 size, and are designed in a 0.35um four metal double poly mixed signal CMOS process. The simulation results show that the designed analog to digital converter has an accuracy of 0.2mV and can achieve the dynamic range of 88dB. The proposed circuits realize the low noise and high speed digital output of read out integrated circuits for ultraviolet imaging sensors.

  8. Using Spatially Varying Pixels Exposures and Bayer-covered Photosensors for High Dynamic Range Imaging

    CERN Document Server

    Konnik, Mikhail V

    2008-01-01

    The method of a linear high dynamic range imaging using solid-state photosensors with Bayer colour filters array is provided in this paper. Using information from neighbour pixels, it is possible to reconstruct linear images with wide dynamic range from the oversaturated images. Bayer colour filters array is considered as an array of neutral filters in a quasimonochromatic light. If the camera's response function to the desirable light source is known then one can calculate correction coefficients to reconstruct oversaturated images. Reconstructed images are linearized in order to provide a linear high dynamic range images for optical-digital imaging systems. The calibration procedure for obtaining the camera's response function to the desired light source is described. Experimental results of the reconstruction of the images from the oversaturated images are presented for red, green, and blue quasimonochromatic light sources. Quantitative analysis of the accuracy of the reconstructed images is provided.

  9. ARCONS: A 2024 Pixel Optical through Near-IR Cryogenic Imaging Spectrophotometer

    CERN Document Server

    Mazin, B A; Strader, M J; Bumble, B; O'Brien, K; Szypryt, P; Marsden, D; van Eyken, J C; Duggan, G E; Ulbricht, G; Stoughton, C; Johnson, M

    2013-01-01

    We present the design, construction, and commissioning results of ARCONS, the Array Camera for Optical to Near-IR Spectrophotometry. ARCONS is the first ground-based instrument in the optical through near-IR wavelength range based on Microwave Kinetic Inductance Detectors (MKIDs). MKIDs are revolutionary cryogenic detectors, capable of detecting single photons and measuring their energy without filters or gratings, similar to an X-ray microcalorimeter. MKIDs are nearly ideal, noiseless photon detectors, as they do not suffer from read noise or dark current and have nearly perfect cosmic ray rejection. ARCONS is an Integral Field Spectrograph (IFS) containing a lens-coupled 2024 pixel MKID array yielding a 20"x20" field of view, and has been deployed on the Palomar 200" and Lick 120" telescopes for 24 nights of observing. We present initial results showing that ARCONS and its MKID arrays are now a fully operational and powerful tool for astronomical observations.

  10. Design of 90×8 ROIC with pixel level digital TDI implementation for scanning type LWIR FPAs

    Science.gov (United States)

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

    2013-06-01

    Design of a 90×8 CMOS readout integrated circuit (ROIC) based on pixel level digital time delay integration (TDI) for scanning type LWIR focal plane arrays (FPAs) is presented. TDI is implemented on 8 pixels which improves the SNR of the system with a factor of √8. Oversampling rate of 3 improves the spatial resolution of the system. TDI operation is realized with a novel under-pixel analog-to-digital converter, which improves the noise performance of ROIC with a lower quantization noise. Since analog signal is converted to digital domain in-pixel, non-uniformities and inaccuracies due to analog signal routing over large chip area is eliminated. Contributions of each pixel for proper TDI operation are added in summation counters, no op-amps are used for summation, hence power consumption of ROIC is lower than its analog counterparts. Due to lack of multiple capacitors or summation amplifiers, ROIC occupies smaller chip area compared to its analog counterparts. ROIC is also superior to its digital counterparts due to novel digital TDI implementation in terms of power consumption, noise and chip area. ROIC supports bi-directional scan, multiple gain settings, bypass operation, automatic gain adjustment, pixel select/deselect, and is programmable through serial or parallel interface. Input referred noise of ROIC is less than 750 rms electrons, while power consumption is less than 20mW. ROIC is designed to perform both in room and cryogenic temperatures.

  11. Construction and Testing of a Pixellated CZT Detector and Shield for a Hard X-ray Astronomy Balloon Flight

    OpenAIRE

    Bloser, P. F.; Narita, T; Jenkins, J. A.; Grindlay, J.E.

    2000-01-01

    We report on the construction and laboratory testing of pixellated CZT detectors mounted in a flip-chip, tiled fashion and read out by an ASIC, as required for proposed hard X-ray astronomy missions. Two 10 mm x 10 mm x 5 mm detectors were fabricated, one out of standard eV Products high-pressure Bridgman CZT and one out of IMARAD horizontal Bridgman CZT. Each was fashioned with a 4 x 4 array of gold pixels on a 2.5 mm pitch with a surrounding guard ring. The detectors were mounted side by si...

  12. A compact 64-pixel CsI(T1)/Si PIN photodiode imaging module with IC readout

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, Gregory J.; Choong, Woon-Seng; Moses, William W.; Derenzo, Stephen E.; Holland, Stephen E.; Pedrali-Noy, Marzio; Krieger, Brad; Mandelli, Emanuele; Meddeler, Gerrit; Wang, Nadine W.

    2001-08-09

    We characterize the performance of a complete 64-pixel compact gamma camera imaging module consisting of optically isolated 3 mm 3 mm 5 mm CsI(Tl) crystals coupled to a custom array of low-noise Si PIN photodiodes read out by a custom IC. At 50 V bias the custom 64-pixel photodiode arrays demonstrate an average leakage current of 28 pA per 3 mm 3 mm pixel, a 98.5 percent yield of pixels with <100 pA leakage, and a quantum efficiency of about 80 percent for 540 nm CsI(Tl) scintillation photons. The custom 64-channel readout IC uses low-noise preamplifiers, shaper amplifiers, and a winner-take-all (WTA) multiplexer. The IC demonstrates maximum gain of 120 mV / 1000 e-, the ability to select the largest input signal in less than 150 ns, and low electronic noise at 8 ms peaking time ranging from 25 e- rms (unloaded) to an estimated 180 e- rms (photodiode load of 3 pF, 50 pA). At room temperature a complete 64-pixel detector module employing a custom photodiode array and readout IC demonstrates an average energy resolution of 23.4 percent fwhm and an intrinsic spatial resolution of 3.3 mm fwhm for the 140 keV emissions of 99mTc. Construction of an array of such imaging modules is straightforward, hence this technology shows strong potential for numerous compact gamma camera applications, including scintimammography.

  13. NFAD Arrays for Single Photon Optical Communications at 1.5 um Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For this program, we propose to develop large pixel-count single photon counting detector arrays suitable for deployment in spacecraft terminal receivers supporting...

  14. A 32x32 Direct Hybrid Germanium Photoconductor Array with CTIA Readout Multiplexer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal introduces an innovative concept aimed to develop, for the first time, a 1k pixel far infrared focal-plane array with the following key design...

  15. NFAD Arrays for Single Photon Optical Communications at 1.5 um Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For this program, we propose to develop large pixel-count single photon counting detector arrays suitable for deployment in spacecraft terminal receivers supporting...

  16. High Performance Dual Band Photodetector Arrays for MWIR/LWIR Imaging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed Phase II program seeks to create dual-band pixel-collocated MWIR/LWIR photodetector arrays based on III-V semiconductor materials in a Type-II...

  17. Light-Patterned Current Generation in a Droplet Bilayer Array

    Science.gov (United States)

    Restrepo Schild, Vanessa; Booth, Michael J.; Box, Stuart J.; Olof, Sam N.; Mahendran, Kozhinjampara R.; Bayley, Hagan

    2017-04-01

    We have created a 4 × 4 droplet bilayer array comprising light-activatable aqueous droplet bio-pixels. Aqueous droplets containing bacteriorhodopsin (bR), a light-driven proton pump, were arranged on a common hydrogel surface in lipid-containing oil. A separate lipid bilayer formed at the interface between each droplet and the hydrogel; each bilayer then incorporated bR. Electrodes in each droplet simultaneously measured the light-driven proton-pumping activities of each bio-pixel. The 4 × 4 array derived by this bottom-up synthetic biology approach can detect grey-scale images and patterns of light moving across the device, which are transduced as electrical current generated in each bio-pixel. We propose that synthetic biological light-activatable arrays, produced with soft materials, might be interfaced with living tissues to stimulate neuronal pathways.

  18. Fast Sub-Pixel Motion Estimation Algorithm For H.264

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A novel fast sub-pixel search algorithm is proposed to accelerate sub-pixel search. Based on the features of predicted motion vector (PMV) and texture direction observed, the proposed method effectively filters out impossible points and thus decreases 11 searched points in average during the sub-pixel search stage. A threshold is also adopted to early terminate the sub-pixel search. Simulation results show that the proposed method can achieve up to 4.8 times faster than full sub-pixel motion search scheme (FSPS) with less than 0.025 dB PSNR losses and 2.2% bitlength increases.

  19. A study in GUI aesthetics for modern pixel art games.

    OpenAIRE

    Grahn, Emma

    2013-01-01

    The clarity and usability of the graphical user interface is very important for the enjoyment of a digital game. Pixel art is an art style with low resolution consisting of a precise placing of pixels, the smallest unit of colour that a screen can display. Pixel art has the potential of being cheap, easy to make and nostalgic, but it takes some skill to handle. However the great weakness of pixel art is displaying letters, and small details with clarity. So is there a place for pixel art in m...

  20. Multicolor photonic crystal laser array

    Science.gov (United States)

    Wright, Jeremy B; Brener, Igal; Subramania, Ganapathi S; Wang, George T; Li, Qiming

    2015-04-28

    A multicolor photonic crystal laser array comprises pixels of monolithically grown gain sections each with a different emission center wavelength. As an example, two-dimensional surface-emitting photonic crystal lasers comprising broad gain-bandwidth III-nitride multiple quantum well axial heterostructures were fabricated using a novel top-down nanowire fabrication method. Single-mode lasing was obtained in the blue-violet spectral region with 60 nm of tuning (or 16% of the nominal center wavelength) that was determined purely by the photonic crystal geometry. This approach can be extended to cover the entire visible spectrum.

  1. Dynamical pixel manipulation of metasurfaces (Conference Presentation)

    Science.gov (United States)

    Zhong, Jin-Qian

    2017-05-01

    Two-dimensional (2D) metamaterials or known as metasurfaces have attracted researchers' attention due to their capability to manipulate the amplitudes, phases and polarization states of incident electromagnetic waves by conferring extra phase different phase at different positions through a super cell that is composed of different oriented structures. In other words, metasurfaces can achieve beam steering and wave shaping by imparting local, gradient phase shift to the incoming waves. With these abilities, metasurfaces can be applied to applications such as ultrathin invisibility cloaks, metasurface holograms, planar lenses and a vortex generator. With the above mentioned advantages and applications of metasurfaces, yet, all the demonstrated metasurfaces possess a main insufficiency that once the metasurfaces are designed and fabricated, their optical properties are then fixed without any chance for further manipulation, which limits their versatility in practical applications. Moreover, although some researchers employed dynamically changeable materials to achieve an active metasurface, such manipulation can only change the overall performance such as an operating frequency instead of changing the provided phase on each pixel of a metasurface. To solve this issue, we employ liquid crystal integrated with a metasurface and the combination could be thus be dynamically tuned via electric bias on each pixel of liquid crystals. Through this setup, we can alter the polarization state of the incident electromagnetic wave dynamically and thus manipulate the extra phase provided by each pixel. In this combination, liquid crystal is employed to change the incident polarization from 0 to 360-degree and the metasurface is designed to achieve four different output signals including phase modulated linear- and circular-polarized light and amplitude-modulated linear- and circular-polarized light. Meanwhile, the metasurfaces could also control the transmission efficiency of the

  2. Optical Cloud Pixel Recovery via Machine Learning

    Directory of Open Access Journals (Sweden)

    Subrina Tahsin

    2017-05-01

    Full Text Available Remote sensing derived Normalized Difference Vegetation Index (NDVI is a widely used index to monitor vegetation and land use change. NDVI can be retrieved from publicly available data repositories of optical sensors such as Landsat, Moderate Resolution Imaging Spectro-radiometer (MODIS and several commercial satellites. Studies that are heavily dependent on optical sensors are subject to data loss due to cloud coverage. Specifically, cloud contamination is a hindrance to long-term environmental assessment when using information from satellite imagery retrieved from visible and infrared spectral ranges. Landsat has an ongoing high-resolution NDVI record starting from 1984. Unfortunately, this long time series NDVI data suffers from the cloud contamination issue. Though both simple and complex computational methods for data interpolation have been applied to recover cloudy data, all the techniques have limitations. In this paper, a novel Optical Cloud Pixel Recovery (OCPR method is proposed to repair cloudy pixels from the time-space-spectrum continuum using a Random Forest (RF trained and tested with multi-parameter hydrologic data. The RF-based OCPR model is compared with a linear regression model to demonstrate the capability of OCPR. A case study in Apalachicola Bay is presented to evaluate the performance of OCPR to repair cloudy NDVI reflectance. The RF-based OCPR method achieves a root mean squared error of 0.016 between predicted and observed NDVI reflectance values. The linear regression model achieves a root mean squared error of 0.126. Our findings suggest that the RF-based OCPR method is effective to repair cloudy pixels and provides continuous and quantitatively reliable imagery for long-term environmental analysis.

  3. ATLAS Tracker and Pixel Operational Experience

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00222525; The ATLAS collaboration

    2016-01-01

    The tracking performance of the ATLAS detector relies critically on the silicon and gaseous tracking subsystems that form the ATLAS Inner Detector. Those subsystems have undergone significant hardware and software upgrades to meet the challenges imposed by the higher collision energy, pileup and luminosity that are being delivered by the LHC during Run2. The key status and performance metrics of the Pixel Detector and the Semi Conductor Tracker, are summarised, and the operational experience and requirements to ensure optimum data quality and data taking efficiency are described.

  4. CMB component separation in the pixel domain

    OpenAIRE

    Doroshkevich, A.; Verkhodanov, O.

    2010-01-01

    We show that the popular ILC approach is unstable in respect to the division of the sample of map pixels to the set of ``homogeneous'' subsamples. For suitable choice of such subsamples we can obtain the restored CMB signal with amplitudes ranged from zero to the amplitudes of the observed signal. We propose approach which allows us to obtain reasonable estimates of $C_\\ell$ at $\\ell\\leq 30$ and similar to WMAP $C_\\ell$ for larger $\\ell$. With this approach we reduce some anomalies of the WMA...

  5. Reading pixelized paragraphs of Chinese characters using simulated prosthetic vision.

    Science.gov (United States)

    Zhao, Ying; Lu, Yanyu; Zhao, Ji; Wang, Kaihu; Ren, Qiushi; Wu, Kaijie; Chai, Xinyu

    2011-07-29

    Visual prostheses offer a possibility of restoring useful reading ability to the blind. The psychophysics of simulating reading with a prosthesis using pixelized text has attracted attention recently. This study was an examination of the reading accuracy and efficiency of pixelized Chinese paragraphs after different parameters were altered. Forty native Chinese speakers with normal or corrected visual acuity (20/20) participated in four experiments. Reading accuracy and efficiency were measured after changing the character resolution, character size, pixel dropout percentage, number of gray levels, and luminance. A 5° × 5° character appeared to be the optimal size necessary for accurate pixelized reading. Reading accuracy close to 100% could be achieved with 10 × 10 pixels/character and ∼60% with a 6 × 6 pixel resolution. Pixel dropout adversely affected accuracy, and paragraphs with a 50% dropout were unreadable. Luminance had little effect; however, the number of gray levels significantly affected reading performance. Paragraph reading was at least 5% more accurate at each resolution than was the accuracy of Chinese character recognition. Character size and resolution, pixel dropout, and the number of gray levels clearly affected the reading performance of pixelized Chinese paragraphs. Compared with pixelized character recognition, pixelized Chinese paragraph reading achieved higher accuracy; thus, optimal Chinese reading performance may require prostheses with more electrodes (1000) than are required to read paragraphs in the Latin alphabet (500).

  6. 3D-FBK pixel sensors with CMS readout: First test results

    Energy Technology Data Exchange (ETDEWEB)

    Obertino, M., E-mail: margherita.obertino@cern.ch [Università del Piemonte Orientale, Novara, and INFN, Torino (Italy); Solano, A. [Università di Torino and INFN, Torino (Italy); Vilela Pereira, A. [INFN, Torino (Italy); Alagoz, E. [Physics Department, Purdue University, West Lafayette, IN (United States); Andresen, J. [Colorado University, Colorado (United States); Arndt, K.; Bolla, G.; Bortoletto, D. [Physics Department, Purdue University, West Lafayette, IN (United States); Boscardin, M. [Centro per i Materiali e i Microsistemi Fondazione Bruno Kessler (FBK), Povo di Trento (Italy); Brosius, R. [SUNY, Buffalo (United States); Bubna, M. [Physics Department, Purdue University, West Lafayette, IN (United States); Dalla Betta, G.-F. [INFN Padova (Gruppo Collegato di Trento) and Università di Trento, Povo di Trento (Italy); Jensen, F. [Colorado University, Colorado (United States); Krzywda, A. [Physics Department, Purdue University, West Lafayette, IN (United States); Kumar, A. [SUNY, Buffalo (United States); Kwan, S. [Università di Milano Bicocca and INFN, Milano (Italy); Lei, C.M. [Colorado University, Colorado (United States); Menasce, D.; Moroni, L. [INFN Milano Bicocca, Milano (Italy); Ngadiuba, J. [Università di Milano Bicocca and INFN, Milano (Italy); and others

    2013-08-01

    Silicon 3D detectors consist of an array of columnar electrodes of both doping types which penetrate entirely in the detector bulk, perpendicularly to the surface. They are emerging as one of the most promising technologies for innermost layers of tracking devices for the foreseen upgrades of the LHC. Until recently, properties of 3D sensors have been investigated mostly with ATLAS readout electronics. 3D pixel sensors compatible with the CMS readout were first fabricated at SINTEF (Oslo, Norway), and more recently at FBK (Trento, Italy) and CNM (Barcelona, Spain). Several sensors with different electrode configurations, bump-bonded with the CMS pixel PSI46 readout chip, were characterized in laboratory and tested at Fermilab with a proton beam of 120 GeV/c. Preliminary results of the data analysis are presented.

  7. Performance limits of a single photon counting pixel system

    Energy Technology Data Exchange (ETDEWEB)

    Chmeissani, M.; Mikulec, B. E-mail: bettina.mikulec@cern.ch

    2001-03-11

    X-ray imaging using hybrid pixel detectors in single photon counting mode is a relatively recent and exciting development. The photon counting mode implies that each pixel has a threshold in energy above which a hit is recorded. Sharing of charge between adjacent pixels would therefore lead to a loss of registered hits and for medical imaging applications to a higher patient dose. This explains why the demand for high spatial resolution and consequently small pixel sizes (<100 {mu}m) motivates the Medipix2 collaboration to study the effects of charge sharing between pixels on system performance. Two different simulation codes are used to simulate the energy loss inside the detector and the charge transport towards the pixel electrodes. The largest contribution to the lateral spreading of charge comes from diffusion and can result in a considerable loss of detection efficiency in photon counting systems for small pixel sizes.

  8. Pixel 2010: A résumé

    CERN Document Server

    Wermes, Norbert

    2011-01-01

    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.

  9. Actively addressed single pixel full-colour plasmonic display

    Science.gov (United States)

    Franklin, Daniel; Frank, Russell; Wu, Shin-Tson; Chanda, Debashis

    2017-05-01

    Dynamic, colour-changing surfaces have many applications including displays, wearables and active camouflage. Plasmonic nanostructures can fill this role by having the advantages of ultra-small pixels, high reflectivity and post-fabrication tuning through control of the surrounding media. However, previous reports of post-fabrication tuning have yet to cover a full red-green-blue (RGB) colour basis set with a single nanostructure of singular dimensions. Here, we report a method which greatly advances this tuning and demonstrates a liquid crystal-plasmonic system that covers the full RGB colour basis set, only as a function of voltage. This is accomplished through a surface morphology-induced, polarization-dependent plasmonic resonance and a combination of bulk and surface liquid crystal effects that manifest at different voltages. We further demonstrate the system's compatibility with existing LCD technology by integrating it with a commercially available thin-film-transistor array. The imprinted surface interfaces readily with computers to display images as well as video.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sadygov, Z. [National Nuclear Research Center, Baku (Azerbaijan); Joint Institute for Nuclear Research, Dubna (Russian Federation); Ahmadov, F. [National Nuclear Research Center, Baku (Azerbaijan); Khorev, S. [Zecotek Photonics Inc., Vancouver (Canada); Sadigov, A., E-mail: saazik@yandex.ru [National Nuclear Research Center, Baku (Azerbaijan); Suleymanov, S. [National Nuclear Research Center, Baku (Azerbaijan); Madatov, R.; Mehdiyeva, R. [Institute of Radiation Problems, Baku (Azerbaijan); Zerrouk, F. [Zecotek Photonics Inc., Vancouver (Canada)

    2016-07-11

    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).

  11. Interconnect and bonding techniques for pixelated X-ray and gamma-ray detectors

    Science.gov (United States)

    Schneider, A.; Veale, M. C.; Duarte, D. D.; Bell, S. J.; Wilson, M. D.; Lipp, J. D.; Seller, P.

    2015-02-01

    In the last decade, the Detector Development Group at the Technology Department of the Science and Technology Facilities Council (STFC), U.K., established a variety of fabrication and bonding techniques to build pixelated X-ray and γ-ray detector systems such as the spectroscopic X-ray imaging detector HEXITEC [1]. The fabrication and bonding of such devices comprises a range of processes including material surface preparation, photolithography, stencil printing, flip-chip and wire bonding of detectors to application-specific integrated circuits (ASIC). This paper presents interconnect and bonding techniques used in the fabrication chain for pixelated detectors assembled at STFC. For this purpose, detector dies (~ 20× 20 mm2) of high quality, single crystal semiconductors, such as cadmium zinc telluride (CZT) are cut to the required thickness (up to 5mm). The die surfaces are lapped and polished to a mirror-finish and then individually processed by electroless gold deposition combined with photolithography to form 74× 74 arrays of 200 μ m × 200 μ m pixels with 250 μ m pitch. Owing to a lack of availability of CZT wafers, lithography is commonly carried out on individual detector dies which represents a significant technical challenge as the edge of the pixel array and the surrounding guard band lies close to the physical edge of the crystal. Further, such detector dies are flip-chip bonded to readout ASIC using low-temperature curing silver-loaded epoxy so that the stress between the bonded detector die and the ASIC is minimized. In addition, this reduces crystalline modifications of the detector die that occur at temperature greater than 150\\r{ }C and have adverse effects on the detector performance. To allow smaller pitch detectors to be bonded, STFC has also developed a compression cold-weld indium bump bonding technique utilising bumps formed by a photolithographic lift-off technique.

  12. Position-Sensitive Detector with Depth-of-Interaction Determination for Small Animal PET

    CERN Document Server

    Fedorov, A; Kholmetsky, A L; Korzhik, M V; Lecoq, P; Lobko, A S; Missevitch, O V; Tkatchev, A

    2002-01-01

    Crystal arrays made of LSO and LuAP crystals 2x2x10 mm pixels were manufactured for evaluation of detector with depth-of-interaction (DOI) determination capability intended for small animal positron emission tomograph. Position-sensitive LSO/LuAP phoswich DOI detector based on crystal 8x8 arrays and HAMAMATSU R5900-00-M64 position-sensitive multi-anode photomultiplier tube was developed and evaluated. Time resolution was found to be not worse than 1.0 ns FWHM for both layers, and spatial resolution mean value was 1.5 mm FWHM for the center of field-of-view.

  13. The ALICE Silicon Pixel Detector System

    CERN Document Server

    Fadmar Osmic, FO

    2006-01-01

    The European Organization for Particle Physics (CERN) in Geneva is currently constructing the Large Hadron Collider (LHC), which will allow the study of the subnuclear ranges of physics with an accuracy never achieved before. Within the LHC project, ALICE is to the study of strongly interacting matter at extreme densities and high temperatures. ALICE as many other modern High Energy Physics (HEP) experiments uses silicon pixel detectors for tracking close to the interaction point (IP). The ALICE Silicon Pixel Detector (SPD) will constitute the two innermost layers of ALICE, and will due to its high granularity provide precise tracking information. In heavy ion collisions, the track density could be as high as 80 tracks/cm2 in the first SPD layer. The SPD will provide tracking information at radii of 3.9 and 7.6 cm from the IP. It is a fundamental element for the study of the weak decays of the particles carrying heavy flavour, whose typical signature will be a secondary vertex separated from the primary verte...

  14. Silicon pixel R&D for CLIC

    CERN Document Server

    AUTHOR|(SzGeCERN)754303

    2016-01-01

    Challenging detector requirements are imposed by the physics goals at the future multi-TeV e+e- Compact Linear Collider (CLIC). A single point resolution of 3μm for the vertex detector and 7μm for the tracker is required. Moreover, the CLIC vertex detector and tracker need to be extremely light weighted with a material budget of 0.2 % X0 per layer in the ver- tex detector and 1-2%X0 in the tracker. A fast time slicing of 10ns is further required to suppress background from beam-beam interactions. A wide range of sensor and readout ASIC technologies are investigated within the CLIC silicon pixel R&D effort. Various hybrid planar sensor assemblies with a pixel size of 25x25μm2 and 55x55μm2 have been produced and characterised by laboratory measurements and during test-beam campaigns. Experimental and simulation results for thin (50μm-500μm) slim edge and active-edge planar, and High-Voltage CMOS sensors hybridised to various readout ASICs (Timepix, Timepix3, CLICpix) are presented.

  15. Silicon pixel R&D for CLIC

    Science.gov (United States)

    Munker, M.

    2017-01-01

    Challenging detector requirements are imposed by the physics goals at the future multi-TeV e+ e‑ Compact Linear Collider (CLIC). A single point resolution of 3 μm for the vertex detector and 7 μm for the tracker is required. Moreover, the CLIC vertex detector and tracker need to be extremely light weighted with a material budget of 0.2% X0 per layer in the vertex detector and 1–2% X0 in the tracker. A fast time slicing of 10 ns is further required to suppress background from beam-beam interactions. A wide range of sensor and readout ASIC technologies are investigated within the CLIC silicon pixel R&D effort. Various hybrid planar sensor assemblies with a pixel size of 25×25 μm2 and 55×55 μm2 have been produced and characterised by laboratory measurements and during test-beam campaigns. Experimental and simulation results for thin (50 μm–500 μm) slim edge and active-edge planar, and High-Voltage CMOS sensors hybridised to various readout ASICs (Timepix, Timepix3, CLICpix) are presented.

  16. The Phase1 CMS Pixel detector upgrade

    CERN Document Server

    Tavolaro, Vittorio Raoul

    2016-01-01

    The pixel detector of the CMS experiment will be replaced in an extended end-of-year shutdown during winter 2016/2017 with an upgraded one able to cope with peak instantaneous luminosities beyond the nominal LHC instantaneous luminosity of $1 \\times 10^{34}$ cm$^{-2}$ s$^{-1}$. Under the conditions expected in the coming years, which will see an increase of a factor two in instantaneous luminosity, the present system would experience a dynamic inefficiency caused mainly by data losses due to buffer overflows. The Phase I upgrade of the CMS pixel detector, described in this paper, will operate at full efficiency at an instantaneous luminosity of $2 \\times 10^{34}$ cm$^{-2}$ s$^{-1}$, thanks to a new readout chip. The new detector will feature one additional tracking point both in the barrel and in the forward regions, while reducing the material budget as a result of a new CO$_{2}$ cooling system and optimised layout of the services. In this paper, the design and the technological choices of the Phase I detect...

  17. optical links for the atlas pixel detector

    CERN Document Server

    Stucci, Stefania Antonia; The ATLAS collaboration

    2015-01-01

    Optical links are necessary to satisfy the high speed readout over long distances for advanced silicon detector systems. We report on the optical readout used in the newly installed central pixel layer (IBL) in the ATLAS experiment. The off detector readout employs commercial optical to analog converters, which were extensively tested for this application. Performance measurements during installation and commissioning will be shown. With the increasing instantaneous luminosity in the next years, the next layers outwards of IBL of the ATLAS Pixel detector (Layer 1 and Layer 2) will reach their bandwidth limits. A plan to increase the bandwidth by upgrading the off detector readout chain is put in place. The plan also involves new optical readout components, in particular the optical receivers, for which commercial units cannot be used and a new design has been made. The latter allows for a wider operational range in term of data frequency and light input power to match the on-detector sending units on the pres...

  18. Optical links for the ATLAS Pixel detector

    CERN Document Server

    Stucci, Stefania Antonia; The ATLAS collaboration

    2015-01-01

    Optical links are necessary to satisfy the high speed readout over long distances for advanced silicon detector systems. We report on the optical readout used in the newly installed central pixel layer (IBL) in the ATLAS experiment. The off detector readout employs commercial optical to analog converters, which were extensively tested for this application. Performance measurements during installation and commissioning will be shown. With the increasing instantaneous luminosity in the next years, the next layers outwards of IBL of the ATLAS Pixel detector (Layer 1 and Layer 2) will reach their bandwidth limits. A plan to increase the bandwidth by upgrading the off detector readout chain is put in place. The plan also involves new optical readout components, in particular the optical receivers, for which commercial units cannot be used and a new design has been made. The latter allows for a wider operational range in term of data frequency and light input power to match the on-detector sending units on the pres...

  19. The Phase II ATLAS ITk Pixel Upgrade

    CERN Document Server

    Terzo, Stefano; The ATLAS collaboration

    2017-01-01

    The entire tracking system of the ATLAS experiment will be replaced during the LHC Phase II shutdown (foreseen to take place around 2025) by an all-silicon detector called the "ITk" (Inner Tracker). The innermost portion of ITk will consist of a pixel detector with five layers in the barrel region and and ring-shaped supports in the endcap regions. It will be instrumented with new sensor and readout electronics technologies to improve the tracking performance and cope with the HL-LHC environment, which will be severe in terms of occupancy and radiation. The total surface area of silicon in the new pixel system could measure up to 14 m$^2$ , depending on the final layout choice, which is expected to take place in early 2017. Several layout options are being investigated at the moment, including some with novel inclined support structures in the barrel-endcap overlap region and others with very long innermost barrel layers. Forward coverage could be as high as $|\\eta| < 4$. Supporting structures will be ...

  20. The Phase-2 ATLAS ITk Pixel Upgrade

    CERN Document Server

    Flick, Tobias; The ATLAS collaboration

    2016-01-01

    The entire tracking system of the ATLAS experiment will be replaced during the LHC Phase II shutdown (foreseen to take place around 2025) by an all-silicon detector called the “ITk” (Inner Tracker). The pixel detector will comprise the five innermost layers, and will be instrumented with new sensor and readout electronics technologies to improve the tracking performance and cope with the HL-LHC environment, which will be severe in terms of occupancy and radiation. The total surface area of silicon in the new pixel system could measure up to 14 m2, depending on the final layout choice, which is expected to take place in early 2017. Four layout options are being investigated at the moment, two with forward coverage to |eta| < 3.2 and two to |eta| < 4. For each coverage option, a layout with long barrel staves and a layout with novel inclined support structures in the barrel-endcap overlap region are considered. All potential layouts include modules mounted on ring-shaped supports in the endcap regions...

  1. Further applications for mosaic pixel FPA technology

    Science.gov (United States)

    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. The Pixels system: last but not late!

    CERN Multimedia

    Kevin Einsweiler

    The Pixel Detector for ATLAS is one of the smallest, but most challenging components of the experiment. It lives in the dangerous territory directly outside the beampipe, where the radiation environment is particularly fierce, and it must be roughly one million times more radiation-hard than its human designers. Starting at a radius of just 5cm from the interaction point where the proton beams collide, it occupies a volume of slightly more than one meter in length and a half meter in diameter. In this compact region, there are eighty million channels of electronics (most of the electronics channels in ATLAS!), each capable of measuring the charge deposited by a track in a silicon pixel measuring only 50 microns by 400 microns in size (a volume of 0.005 cubic millimeters). A total cooling capacity of 15 KWatts is available to keep it operating comfortably at -5C. This detector is built around, and provides the support for, the central beampipe of ATLAS. It is supported on carbon fiber rails inside of the Pix...

  3. Efficient single pixel imaging in Fourier space

    Science.gov (United States)

    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.

  4. Pixel-Tilecal-MDT Combined Test Beam

    CERN Multimedia

    B. Di Girolamo

    A test with many expectations When an additional week of running (from September 11th to 18th) was allocated for the test-beam, it was decided to give priority to a combined run with the participation of the Pixel, Tilecal and MDT sub-detectors. The integration of these three sub-detectors was possible as they all use the baseline (DAQ-1/EF based) DAQ for test beams (as reported in a previous e-news). The tests and the addition of a common trigger and busy were organized in a short timescale by experts from the three sub-detectors and DAQ/EF. The expectations were many; both looking for problems and finding solutions. The setup The setup, shown in the figure, consisted of the Pixel telescope normally used during the sub-detector tests, two Tilecal barrel modules, two Tilecal extended barrel modules, and six MDT barrel chambers. This fully occupied a length of some 30 meters in the H8 line of the SPS North Area. Each sub-detector used their own specialized front-end electronics. The data collected by modu...

  5. ATLAS rewards two pixel detector suppliers

    CERN Multimedia

    2007-01-01

    Peter Jenni, ATLAS spokesperson, presented the ATLAS supplier award to Herbert Reichl, IZM director, and to Simonetta Di Gioia, from the SELEX company.Two of ATLAS’ suppliers were awarded prizes at a ceremony on Wednesday 13 June attended by representatives of the experiment’s management and of CERN. The prizes went to the Fraunhofer Institut für Zuverlässigkeit und Mikrointegration (IZM) in Berlin and the company SELEX Sistemi Integrati in Rome for the manufacture of modules for the ATLAS pixel detector. SELEX supplied 1500 of the modules for the tracker, while IZM produced a further 1300. The modules, each made up of 46080 channels, form the active part of the ATLAS pixel detector. IZM and SELEX received the awards for the excellent quality of their work: the average number of faulty channels per module was less than 2.10-3. They also stayed within budget and on schedule. The difficulty they faced was designing modules based on electronic components and sensor...

  6. 1D pixelated MV portal imager with structured privacy film: a feasibility study

    Science.gov (United States)

    Baturin, Pavlo; Shedlock, Daniel; Myronakis, Marios; Berbeco, Ross; Star-Lack, Josh

    2017-03-01

    Modern amorphous silicon flat panel-based electronic portal imaging devices that utilize thin gadolinium oxysulfide scintillators suffer from low quantum efficiencies (QEs). Thick two dimensionally (2D) pixelated scintillator arrays offer an effective but expensive option for increasing QE. To reduce costs, we have investigated the possibility of combining a thick one dimensional (1D) pixelated scintillator (PS) with an orthogonally placed 1D structured optical filter to provide for overall good 2D spatial resolution. In this work, we studied the potential for using a 1D video screen privacy film (PF) to serve as a directional optical attenuator and filter. A Geant4 model of the PF was built based on reflection and transmission measurements taken with a laser-based optical reflectometer. This information was incorporated into a Geant4-based x-ray detector simulator to generate modulation transfer functions (MTFs), noise power spectra (NPS), and detective quantum efficiencies (DQEs) for various 1D and 2D configurations. It was found that the 1D array with PF can provide the MTFs and DQEs of 2D arrays. Although the PF significantly reduced the amount of optical photons detected by the flat panel, we anticipate using a scintillator with an inherently high optical yield (e.g. cesium iodide) for MV imaging, where fluence rates are inherently high, will still provide adequate signal intensities for the imaging tasks associated with radiotherapy.

  7. Performance assessment of a single-pixel compressive sensing imaging system

    Science.gov (United States)

    Du Bosq, Todd W.; Preece, Bradley L.

    2016-05-01

    Conventional electro-optical and infrared (EO/IR) systems capture an image by measuring the light incident at each of the millions of pixels in a focal plane array. Compressive sensing (CS) involves capturing a smaller number of unconventional measurements from the scene, and then using a companion process known as sparse reconstruction to recover the image as if a fully populated array that satisfies the Nyquist criteria was used. Therefore, CS operates under the assumption that signal acquisition and data compression can be accomplished simultaneously. CS has the potential to acquire an image with equivalent information content to a large format array while using smaller, cheaper, and lower bandwidth components. However, the benefits of CS do not come without compromise. The CS architecture chosen must effectively balance between physical considerations (SWaP-C), reconstruction accuracy, and reconstruction speed to meet operational requirements. To properly assess the value of such systems, it is necessary to fully characterize the image quality, including artifacts and sensitivity to noise. Imagery of the two-handheld object target set at range was collected using a passive SWIR single-pixel CS camera for various ranges, mirror resolution, and number of processed measurements. Human perception experiments were performed to determine the identification performance within the trade space. The performance of the nonlinear CS camera was modeled with the Night Vision Integrated Performance Model (NV-IPM) by mapping the nonlinear degradations to an equivalent linear shift invariant model. Finally, the limitations of CS modeling techniques will be discussed.

  8. Development of a fully programmable ROIC with 15 μm pixel pitch for MWIR applications

    Science.gov (United States)

    Altun, Oguz; Kepenek, Reha; Tasdemir, Ferhat; Akyurek, Fatih; Tunca, Can; Akbulut, Mehmet; Nuzumlali, Omer Lutfi; Inceturkmen, Ercihan

    2017-02-01

    A 15 μm pixel pitch 640×512 Readout Circuit (ROIC) for MWIR applications is designed and fabricated using 0.18 um CMOS process. The ROIC is implemented using Direct Injection (DI) input stage with programmable pixel gain where maximum full-well-capacity (FWC) is more than 13Mé. All analog current and voltage bias values can be programmed through a digital interface. Additionally, integration time can be programmed with 0.1 µsec resolution by internal timing circuitry. ROIC has 1, 2 and 4 output modes with a frame rate of 120fps at 4 output mode. The design supports IntegrateThen-Read (ITR) and Integrate-While-Read (IWR) modes in snapshot operation. Photodetector reverse bias voltage is controlled by adjusting the bias of the common-gate input stage at the input of DI pixel. An on-chip low-dropout voltage regulator is used to generate the detector common voltage. With 2x2 binning feature, the ROIC can also be used for 30 µm pixel pitch 320x256 photodetector arrays. An Analog-Front-End (AFE) card has been designed to operate the ROIC and to convert analog video output to a 14-bit digital value. This digital video data is handled by external video processor card which supports 1-point and 2-point Non-Uniformity Correction (NUC), histogram equalization, bad pixel replacement and filtering. The ROIC has been extensively tested with a prototype FPA at 77°K. According to these test results, functionality of all modes have been verified and a noise level of 700é is achieved at 4.5Mé FWC.

  9. A CMOS image sensor with draining only modulation pixels for fluorescence lifetime imaging

    Science.gov (United States)

    Li, Zhuo; Yasutomi, Keita; Takasawa, Taishi; Itoh, Shinya; Kawahito, Shoji

    2011-03-01

    Fluorescence lifetime imaging is becoming a powerful tool in biology. A charge-domain CMOS Fluorescence Lifetime Imaging Microscopy (FLIM) chip using a pinned photo diode (PPD) and the pinned storage diode (PSD) with different depth of potential wells has been previously developed by the authors. However, a transfer gate between PPD and PSD causes charge transfer noise due to traps at the channel surface. This paper presents a time-resolved CMOS image sensor with draining only modulation pixels for fluorescence lifetime imaging, which removes the transfer gate between PPD and PSD. The time windowing is done by draining with a draining gate only, which is attached along the carrier path from PPD to PSD. This allows us to realize a trapping less charge transfer between PPD and PSD, leading to a very low-noise time-resolved signal detection. A video-rate CMOS FLIM chip has been fabricated using 0.18μm standard CMOS pinned diode image sensor process. The pixel consists of a PPD, a PSD, a charge draining gate (TD), a readout transfer gate (TX) between the PSD and the floating diffusion (FD), a reset transistor and a source follower amplifier transistor. The pixel array has 200(Row) x 256(Column) pixels and the pixel pitch is 7.5μm. Fundamental characteristics of the implemented CMOS FLIM chip are measured. The signal intensity of the PSD as a function of the TD gate voltage is also measured. The ratio of the signal for the TD off to the signal for the TD on is 212 : 1.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Fahim, Farah [Northwestern U. (main); Deptuch, Grzegorz W. [Fermilab; Hoff, James R. [Fermilab; Mohseni, Hooman [Northwestern U. (main)

    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

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

    Science.gov (United States)

    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.

  13. Pixel-level Analog-To-Digital Converters for Hybrid Pixel Detectors with energy sensitivity

    NARCIS (Netherlands)

    San Segundo Bello, David; Nauta, Bram; Visschers, Jan

    2000-01-01

    Single-photon counting hybrid pixel detectors have shown to be a valid alternative to other types of X-ray imaging devices due to their high sensitivity, low noise, linear behavior and wide dynamic range. One important advantage of these devices is the fact that detector and readout electronics are

  14. Design of pixel-level ADCs for energy-sensitive hybrid pixel detectors

    NARCIS (Netherlands)

    San Segundo Bello, David; Nauta, Bram; Visschers, Jan

    2000-01-01

    Single-photon counting hybrid pixel detectors have shown to be a valid alternative to other types of X-ray imaging devices due to their high sensitivity, low noise, linear behavior and wide dynamic range. One important advantage of these devices is the fact that detector and readout electronics are

  15. Fabrication of a high-density MCM-D for a pixel detector system using a BCB/Cu technology

    CERN Document Server

    Topper, M; Engelmann, G; Fehlberg, S; Gerlach, P; Wolf, J; Ehrmann, O; Becks, K H; Reichl, H

    1999-01-01

    The MCM-D which is described here is a prototype for a pixel detector system for the planned Large Hadron Collider (LHC) at CERN, Geneva. The project is within the ATLAS experiment. The module consists of a sensor tile with an active area of 16.4 mm*60.4 mm, 16 readout chips, each serving 24*160 pixel unit cells, a module controller chip, an optical transceiver and the local signal interconnection and power distribution buses. The extremely high wiring density which is necessary to interconnect the readout chips was achieved using a thin film copper/photo-BCB process above the pixel array. The bumping of the readout chips was done by PbSn electroplating. All dice are then attached by flip-chip assembly to the sensor diodes and the local buses. The focus of this paper is a detailed description of the technologies for the fabrication of this advanced MCM-D. (10 refs).

  16. A support note for the use of pixel hybrid photon detectors in the RICH counters of LHCb

    CERN Document Server

    Gys, Thierry

    2001-01-01

    This document is a proposal for the use of a hybrid photon detector with integrated silicon pixel readout in the ring imaging Cherenkov detectors of the LHCb experiment. The photon detector is based on a cross-focussed image intensifier tube geometry where the image is de-magnified by a factor of 5. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The document starts with the general specification of the baseline option, followed by a summary of the main results achieved so far during the R&D phase. A future R&D programme and its related time table is also presented. The document concludes with the description of a photon detector production scheme and time schedule.

  17. Multiplexed readout of MMC detector arrays using non-hysteretic rf-SQUIDs

    OpenAIRE

    Kempf, S.; Wegner, M; Gastaldo, L.; Fleischmann, A.; Enss, C.

    2013-01-01

    Metallic magnetic calorimeters (MMCs) are widely used for various experiments in fields ranging from atomic and nuclear physics to x-ray spectroscopy, laboratory astrophysics or material science. Whereas in previous experiments single pixel detectors or small arrays have been used, for future applications large arrays are needed. Therefore, suitable multiplexing techniques for MMC arrays are currently under development. A promising approach for the readout of large arrays is the microwave SQU...

  18. A carbon nanotube field emission multipixel x-ray array source for microradiotherapy application

    OpenAIRE

    Wang, Sigen; Calderon, Xiomara; Peng, Rui; Schreiber, Eric C.; Zhou, Otto; Chang, Sha

    2011-01-01

    The authors report a carbon nanotube (CNT) field emission multipixel x-ray array source for microradiotherapy for cancer research. The developed multipixel x-ray array source has 50 individually controllable pixels and it has several distinct advantages over other irradiation source including high-temporal resolution (millisecond level), the ability to electronically shape the form, and intensity distribution of the radiation fields. The x-ray array was generated by a CNT cathode array (5×10)...

  19. Serial pixel analog-to-digital converter (ADC)

    Science.gov (United States)

    Larson, Eric 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.

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

    Science.gov (United States)

    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.

  1. Nanopillar optical antenna nBn detectors for subwavelength infrared pixels

    Science.gov (United States)

    Hung, Chung Hong; Senanayake, Pradeep; Lee, Wook-Jae; Farrell, Alan; Hsieh, Nick; Huffaker, Diana L.

    2015-06-01

    The size, weight and power (SWaP) of state of the art infrared focal plane arrays are limited by the pixel size approaching the diffraction limit. We investigate a novel detector architecture which allows improvements in detectivity by shrinking the absorber volume while maintaining high quantum efficiency and wide field of view (FOV). It has been previously shown that the Nanopillar Optical Antenna (NOA) utilizes 3D plasmonic modes to funnel light into a subwavelength nanopillar absorber. We show detailed electro-optical simulations for the NOA-nBn architecture for overcoming generation recombination current with suitable surface passivation to achieve background limited infrared performance.

  2. Development of an 80 x 64 pixel, broadband, real-time THz imager

    Science.gov (United States)

    Burdette, Don J.; Alverbro, Jörgen; Zhang, Ze; Fay, Patrick; Ni, Yang; Potet, Pierre; Sertel, Kubilay; Trichopoulos, Gerogios; Topalli, Kagan; Volakis, John; Mosbacker, H. Lee

    2011-05-01

    The widespread adoption of THz based applications has been hindered by the lack of a real-time, broad-band, cost-effective THz camera with sufficient sensitivity to enable applications in markets as diverse as security, non-destructive evaluation, and biomedical imaging. This technological gap can be filled through the development of an 80 x 64 pixel array of Sb-heterostructure backward diodes (Sb-HBDs) monolithically integrated to broadband (600 GHz - 1200 GHz) antennas that can be directly flip-chipped to a CMOS voltage-mode readout integrated circuit (ROIC). This paper outlines the current progress of the project.

  3. A real-time autostereoscopic display method based on partial sub-pixel by general GPU processing

    Science.gov (United States)

    Chen, Duo; Sang, Xinzhu; Cai, Yuanfa

    2013-08-01

    With the progress of 3D technology, the huge computing capacity for the real-time autostereoscopic display is required. Because of complicated sub-pixel allocating, masks providing arranged sub-pixels are fabricated to reduce real-time computation. However, the binary mask has inherent drawbacks. In order to solve these problems, weighted masks are used in displaying based on partial sub-pixel. Nevertheless, the corresponding computations will be tremendously growing and unbearable for CPU. To improve calculating speed, Graphics Processing Unit (GPU) processing with parallel computing ability is adopted. Here the principle of partial sub-pixel is presented, and the texture array of Direct3D 10 is used to increase the number of computable textures. When dealing with a HD display and multi-viewpoints, a low level GPU is still able to permit a fluent real time displaying, while the performance of high level CPU is really not acceptable. Meanwhile, after using texture array, the performance of D3D10 could be double, and sometimes be triple faster than D3D9. There are several distinguishing features for the proposed method, such as the good portability, less overhead and good stability. The GPU display system could also be used for the future Ultra HD autostereoscopic display.

  4. Submission of the first full scale prototype chip for upgraded ATLAS pixel detector at LHC, FE-I4A

    Energy Technology Data Exchange (ETDEWEB)

    Barbero, Marlon, E-mail: barbero@physik.uni-bonn.de [Physikalisches Institut Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany); Arutinov, David [Physikalisches Institut Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany); Beccherle, Roberto; Darbo, Giovanni [INFN Genova, via Dodecaseno 33, IT-16146 Genova (Italy); Dube, Sourabh; Elledge, David; Fleury, Julien [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, CA 94720 (United States); Fougeron, Denis [CPPM Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Garcia-Sciveres, Maurice [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, CA 94720 (United States); Gensolen, Fabrice [CPPM Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Gnani, Dario [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, CA 94720 (United States); Gromov, Vladimir [NIKHEF, Science Park 105, 1098 XG Amsterdam (Netherlands); Jensen, Frank [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, CA 94720 (United States); Hemperek, Tomasz; Karagounis, Michael [Physikalisches Institut Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany); Kluit, Ruud [NIKHEF, Science Park 105, 1098 XG Amsterdam (Netherlands); Kruth, Andre [Physikalisches Institut Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany); Mekkaoui, Abderrezak [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, CA 94720 (United States); Menouni, Mohsine [CPPM Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Schipper, Jan David [NIKHEF, Science Park 105, 1098 XG Amsterdam (Netherlands); and others

    2011-09-11

    A new ATLAS pixel chip FE-I4 is being developed for use in upgraded LHC luminosity environments, including the near-term Insertable B-Layer (IBL) upgrade. FE-I4 is designed in a 130 nm CMOS technology, presenting advantages in terms of radiation tolerance and digital logic density compared to the 0.25{mu}m CMOS technology used for the current ATLAS pixel IC, FE-I3. The FE-I4 architecture is based on an array of 80x336 pixels, each 50x250{mu}m{sup 2}, consisting of analog and digital sections. In the summer 2010, a first full scale prototype FE-I4A was submitted for an engineering run. This IC features the full scale pixel array as well as the complex periphery of the future full-size FE-I4. The FE-I4A contains also various extra test features which should prove very useful for the chip characterization, but deviate from the needs for standard operation of the final FE-I4 for IBL. In this paper, focus will be brought to the various features implemented in the FE-I4A submission, while also underlining the main differences between the FE-I4A IC and the final FE-I4 as envisioned for IBL.

  5. The upGREAT 1.9 THz multi-pixel high resolution spectrometer for the SOFIA Observatory

    Science.gov (United States)

    Risacher, C.; Güsten, R.; Stutzki, J.; Hübers, H.-W.; Bell, A.; Buchbender, C.; Büchel, D.; Csengeri, T.; Graf, U. U.; Heyminck, S.; Higgins, R. D.; Honingh, C. E.; Jacobs, K.; Klein, B.; Okada, Y.; Parikka, A.; Pütz, P.; Reyes, N.; Ricken, O.; Riquelme, D.; Simon, R.; Wiesemeyer, H.

    2016-10-01

    We present a new multi-pixel high resolution (R ≳ 107) spectrometer for the Stratospheric Observatory for Far-Infrared Astronomy (SOFIA). The receiver uses 2 × 7-pixel subarrays in orthogonal polarization, each in an hexagonal array around a central pixel. We present the first results for this new instrument after commissioning campaigns in May and December 2015 and after science observations performed in May 2016. The receiver is designed to ultimately cover the full 1.8-2.5 THz frequency range but in its first implementation, the observing range was limited to observations of the [CII] line at 1.9 THz in 2015 and extended to 1.83-2.07 THz in 2016. The instrument sensitivities are state-of-the-art and the first scientific observations performed shortly after the commissioning confirm that the time efficiency for large scale imaging is improved by more than an order of magnitude as compared to single pixel receivers. An example of large scale mapping around the Horsehead Nebula is presented here illustrating this improvement. The array has been added to SOFIA's instrument suite already for ongoing observing cycle 4. The datacube of the Horsehead observations is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/595/A34

  6. A kilo-pixel imaging system for future space based far-infrared observatories using microwave kinetic inductance detectors

    CERN Document Server

    Baselmans, J J A; Yates, S J C; Yurduseven, O; Llombart, N; Karatsu, K; Baryshev, A M; Ferrari, L; Endo, A; Thoen, D J; de Visser, P J; Janssen, R M J; Murugesan, V; Driessen, E F C; Coiffard, G; Martin-Pintado, J; Hargrave, P; Griffin, M

    2016-01-01

    Future astrophysics and cosmic microwave background space missions operating in the far-infrared to millimetre part of the spectrum will require very large arrays of ultra-sensitive detectors in combination with high multiplexing factors and efficient low- noise and low-power readout systems. We have developed a demonstrator system suitable for such applications. The system combines a 961 pixel imaging array based upon Microwave Kinetic Inductance Detectors (MKIDs) with a readout system capable of reading out all pixels simultaneously with only one readout cable pair and a single cryogenic amplifier. We evaluate, in a representative environment, the system performance in terms of sensitivity, dynamic range, optical efficiency, cosmic ray rejection, pixel-pixel crosstalk and overall yield at an observation frequency of 850 GHz. The overall system has an excellent sensitivity, with an average detector sensitivity NEP=2.8 +- 0.8 x 10^-19 W/rt(Hz) measured using a thermal calibration source. The dynamic range wou...

  7. Silicon buried channels for pixel detector cooling

    Energy Technology Data Exchange (ETDEWEB)

    Boscardin, M., E-mail: boscardi@fbk.eu [Fondazione Bruno Kessler Trento, Via Sommarive 18, I-38123 Trento (Italy); Conci, P.; Crivellari, M.; Ronchin, S. [Fondazione Bruno Kessler Trento, Via Sommarive 18, I-38123 Trento (Italy); Bettarini, S. [Universitá di Pisa, L.go B. Pontecorvo 3, I-56127 Pisa (Italy); Istituto Nazionale di Fisica Nucleare, Sez. di Pisa, L.go B. Pontecorvo 3, I-56127 Pisa (Italy); Bosi, F. [Istituto Nazionale di Fisica Nucleare, Sez. di Pisa, L.go B. Pontecorvo 3, I-56127 Pisa (Italy)

    2013-08-01

    The support and cooling structures add important contributions to the thickness, in radiation length, of vertex detectors. In order to minimize the material budget of pixel sensors, we developed a new approach to integrate the cooling into the silicon devices. The microchannels are formed in silicon using isotropic SF{sub 6} plasma etching in a DRIE (deep reactive ion etcher) equipment. Due to their peculiar profiles, the channels can be sealed by a layer of a PECVD silicon oxide. We have realized on a silicon wafer microchannels with different geometries and hydraulic diameters. We describe the main fabrication steps of microchannels with focus on the channel definition. The experimental results are reported on the thermal characterization of several prototypes, using a mixture of glycol and water as a liquid coolant. The prototypes have shown high cooling efficiency and high-pressure breaking strength.

  8. Artificial Structural Color Pixels: A Review

    Science.gov (United States)

    Zhao, Yuqian; Zhao, Yong; Hu, Sheng; Lv, Jiangtao; Ying, Yu; Gervinskas, Gediminas; Si, Guangyuan

    2017-01-01

    Inspired by natural photonic structures (Morpho butterfly, for instance), researchers have demonstrated varying artificial color display devices using different designs. Photonic-crystal/plasmonic color filters have drawn increasing attention most recently. In this review article, we show the developing trend of artificial structural color pixels from photonic crystals to plasmonic nanostructures. Such devices normally utilize the distinctive optical features of photonic/plasmon resonance, resulting in high compatibility with current display and imaging technologies. Moreover, dynamical color filtering devices are highly desirable because tunable optical components are critical for developing new optical platforms which can be integrated or combined with other existing imaging and display techniques. Thus, extensive promising potential applications have been triggered and enabled including more abundant functionalities in integrated optics and nanophotonics. PMID:28805736

  9. CMB component separation in the pixel domain

    CERN Document Server

    Doroshkevich, A

    2010-01-01

    We show that the popular ILC approach is unstable in respect to the division of the sample of map pixels to the set of ``homogeneous'' subsamples. For suitable choice of such subsamples we can obtain the restored CMB signal with amplitudes ranged from zero to the amplitudes of the observed signal. We propose approach which allows us to obtain reasonable estimates of $C_\\ell$ at $\\ell\\leq 30$ and similar to WMAP $C_\\ell$ for larger $\\ell$. With this approach we reduce some anomalies of the WMAP results. In particular, our estimate of the quadrupole is well consistent to theoretical one, the effect of the ``axis of evil'' is suppressed and the symmetry of the north and south galactic hemispheres increases. This results can change estimates of quadrupole polarization and the redshift of reionization of the Universe. We propose also new simple approach which can improve WMAP estimates of high $\\ell$ power spectrum.

  10. Image Pixel Fusion for Human Face Recognition

    CERN Document Server

    Bhowmik, Mrinal Kanti; Nasipuri, Mita; Basu, Dipak Kumar; Kundu, Mahantapas

    2010-01-01

    In this paper we present a technique for fusion of optical and thermal face images based on image pixel fusion approach. Out of several factors, which affect face recognition performance in case of visual images, illumination changes are a significant factor that needs to be addressed. Thermal images are better in handling illumination conditions but not very consistent in capturing texture details of the faces. Other factors like sunglasses, beard, moustache etc also play active role in adding complicacies to the recognition process. Fusion of thermal and visual images is a solution to overcome the drawbacks present in the individual thermal and visual face images. Here fused images are projected into an eigenspace and the projected images are classified using a radial basis function (RBF) neural network and also by a multi-layer perceptron (MLP). In the experiments Object Tracking and Classification Beyond Visible Spectrum (OTCBVS) database benchmark for thermal and visual face images have been used. Compar...

  11. Operational Experience with the ALICE Pixel detector

    CERN Document Server

    Mastroserio, A.

    2017-01-01

    The Silicon Pixel Detector (SPD) constitutes the two innermost layers of the Inner Tracking System of the ALICE experiment and it is the closest detector to the interaction point. As a vertex detector, it has the unique feature of generating a trigger signal that contributes to the L0 trigger of the ALICE experiment. The SPD started collecting data since the very first pp collisions at LHC in 2009 and since then it has taken part in all pp, Pb-Pb and p-Pb data taking campaigns. This contribution will present the main features of the SPD, the detector performance and the operational experience, including calibration and optimization activities from Run 1 to Run 2.

  12. Astronomical Image Processing with Array Detectors

    CERN Document Server

    Houde, Martin

    2007-01-01

    We address the question of astronomical image processing from data obtained with array detectors. We define and analyze the cases of evenly, regularly, and irregularly sampled maps for idealized (i.e., infinite) and realistic (i.e., finite) detectors. We concentrate on the effect of interpolation on the maps, and the choice of the kernel used to accomplish this task. We show how the normalization intrinsic to the interpolation process must be carefully accounted for when dealing with irregularly sampled grids. We also analyze the effect of missing or dead pixels in the array, and their consequences for the Nyquist sampling criterion.

  13. Irradiation and beam tests qualification for ATLAS IBL Pixel Modules.

    CERN Document Server

    Rubinskiy, Igor; The ATLAS collaboration

    2011-01-01

    The upgrade for the ATLAS detector will undergo different phases towards HL-LHC. The first upgrade for the Pixel Detector will consist in the construction of a new pixel layer which will be installed during the first shutdown of the LHC machine (foreseen for 2013-14). The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of 3.2 cm. The IBL will require the development of several new technologies to cope with increase of radiation or pixel occupancy and also to improve the physics performance which will be achieved by reduction of the pixel size and of the material budget. Two different promising Silicon sensor technologies (Planar n-in-n and 3D) are currently under investigation for the pixel detector. An overview of the sensor technologies qualification with particular emphasis on irradiation and beam tests will be presented.

  14. Irradiation and beam tests qualification for ATLAS IBL Pixel Modules

    CERN Document Server

    Rubinskiy, I

    2013-01-01

    The upgrade for the ATLAS detector will have different steps towards HL-LHC. The first upgrade for the Pixel Detector will consist in the construction of a new pixel layer which will be installed during the first shutdown of the LHC machine (foreseen for 2013–2014). The new detector, called Insertable B-Layer (IBL), will be inserted between the existing Pixel Detector and a new (smaller radius) beam-pipe at a radius of 33 mm. The IBL will require the development of several new technologies to cope with the increase in the radiation damage and the pixel occupancy and also to improve the physics performance, which will be achieved by reduction of the pixel size and of the material budget. Two different promising silicon sensor technologies (Planar n-in-n and 3D) are currently under investigation for the Pixel Detector. An overview of the sensor technologies' qualification with particular emphasis on irradiation and beam tests is presented.

  15. Irradiation and beam tests qualification for ATLAS IBL Pixel Modules

    CERN Document Server

    Rubinskiy, Igor

    2013-01-01

    The upgrade for the ATLAS detector will have different steps towards HL-LHC. The first upgrade for the Pixel Detector will consist in the construction of a new pixel layer which will be installed during the first shutdown of the LHC machine (foreseen for 2013-14). The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of 33 mm. The IBL will require the development of several new technologies to cope with the increase of the radiation damage and the pixel occupancy and also to improve the physics performance, which will be achieved by reduction of the pixel size and of the material budget. Two different promising silicon sensor technologies (Planar n-in-n and 3D) are currently under investigation for the pixel detector. An overview of the sensor technologies’ qualification with particular emphasis on irradiation and beam tests are presented.

  16. Super pixel-level dictionary learning for hyperspectral image classification

    Science.gov (United States)

    Zhao, Wei; Zhu, Wen; Liao, Bo; Fu, Xiangzheng

    2017-08-01

    This paper presents a superpixel-level dictionary learning model for hyperspectral data. The idea is to divide the hyperspectral image into a number of super-pixels by means of the super-pixel segmentation method. Each super-pixel is a spatial neighborhood called contextual group. That is, each pixel is represented using a linear combination of a few dictionary items learned from the train data, but since pixels inside a super-pixel are often consisting of the same materials, their linear combinations are constrained to use common items from the dictionary. To this end, the sparse coefficients of the context group have a common sparse pattern by using the joint sparse regularizer for dictionary learning. The sparse coefficients are then used for classification using linear support vector machines. The validity of the proposed method is experimentally verified on a real hyperspectral images.

  17. Kilopixel X-Ray Microcalorimeter Arrays for Astrophysics: Device Performance and Uniformity

    Science.gov (United States)

    Eckart, M. E.; Adams, J. S.; Bailey, C. N.; Bandler, S. R.; Busch, S. E.; Chervenak, J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. S.; Porst, J.-P.; Sadleir, J. E.; Smith, S. J.

    2012-01-01

    We are developing kilopixel arrays of TES microcalorimeters to enable high-resolution x-ray imaging spectrometers for future x-ray observatories and laboratory astrophysics experiments. Our current array design was targeted as a prototype for the X-ray Microcalorimeter Spectrometer proposed for the International X-ray Observatory, which calls for a 40×40-pixel core array of 300 micron devices with 2.5 eV energy resolution (at 6 keV). Here we present device characterization of our 32×32 arrays, including x-ray spectral performance of individual pixels within the array. We present our results in light of the understanding that our Mo/Au TESs act as weak superconducting links, causing the TES critical current (I(sub c)) and transition shape to oscillate with applied magnetic field (B). We show I(sub c)(B) measurements and discuss the uniformity of these measurements across the array, as well as implications regarding the uniformity of device noise and response. In addition, we are working to reduce pixel-to-pixel electrical and thermal crosstalk; we present recent test results from an array that has microstrip wiring and an angle-evaporated copper backside heatsinking layer, which provides copper coverage on the four sidewalls of the silicon wells beneath each pixel.

  18. Filter arrays

    Energy Technology Data Exchange (ETDEWEB)

    Page, Ralph H.; Doty, Patrick F.

    2017-08-01

    The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

  19. Steganography on quantum pixel images using Shannon entropy

    Science.gov (United States)

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

    2016-07-01

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

  20. CMOS monolithic pixel sensors research and development at LBNL

    Indian Academy of Sciences (India)

    D Contarato; J-M Bussat; P Denes; L Griender; T Kim; T Stezeberger; H Weiman; M Battaglia; B Hooberman; L Tompkins

    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.

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

    CERN Document Server

    Garcia-Sciveres, Maurice

    2016-01-01

    The 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 bits used for by the FE-I4 pixel readout chip of the ATLAS experiment.

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

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Sciveres, Maurice, E-mail: mgs@lbl.gov [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Wang, Xinkang [University of Chicago, Chicago, IL (United States)

    2016-04-11

    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.

  3. A noiseless kilohertz frame rate imaging detector based on microchannel plates read out with the Medipix2 CMOS pixel chip

    CERN Document Server

    Mikulec, Bettina; Ferrère, Didier; La Marra, Daniel; McPhate, J B; Tremsin, A S; Siegmund, O H W; Vallerga, J V; Clement, J; Ponchut, C; Rigal, J M; CERN. Geneva

    2006-01-01

    A new hybrid optical imaging detector is described that is being developed for the next generation adaptive optics (AO) wavefront sensors (WFS) for ground-based telescopes. The detector consists of a photocathode and proximity focused microchannel plates (MCPs) read out by the Medipix2 CMOS pixel ASIC. Each pixel of the Medipix2 device measures 55x55 um2 and comprises pre-amplifier, a window discriminator and a 14-bit counter. The 256x256 Medipix2 array can be read out noiselessly in 287 us. The readout can be electronically shuttered down to a temporal window of a few us. The Medipix2 is buttable on 3 sides to produce 512x(n*256) pixel devices. Measurements with ultraviolet light yield a spatial resolution of the detector at the Nyquist limit. Sub-pixel resolution can be achieved using centroiding algorithms. For the AO application, very high continuous frame rates of the order of 1 kHz are required for a matrix of 512x512 pixels. The design concepts of a parallel readout board are presented that will allow ...

  4. First operation of a hybrid photon detector prototype with electrostatic cross-focussing and integrated silicon pixel readout

    CERN Document Server

    Alemi, M; Gys, Thierry; Mikulec, B; Piedigrossi, D; Puertolas, D; Rosso, E; Schomaker, R; Snoeys, W; Wyllie, Ken H

    2000-01-01

    We report on the first operation of a hybrid photon detector prototype with integrated silicon pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment. The photon detector is based on a cross-focussed image intensifier tube geometry where the image is de-magnified by a factor of 4. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The prototype has been characterized using a low-intensity light-emitting diode operated in pulsed mode. Its performance in terms of single-photoelectron detection efficiency and imaging properties is presented. A model of photoelectron detection is proposed, and is shown to be in good agreement with the experimental data. It includes an estimate of the charge signal generated in the silicon detector, and the combined effects of the comparator threshold spread of the pixel readout chip, charge sharing at the pixel boundaries and back-scattering of the photoelectrons at the silicon detector surface...

  5. Hit efficiency study of CMS prototype forward pixel detectors

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. The FE-I4 pixel readout integrated circuit

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Sciveres, M., E-mail: mgarcia-sciveres@bl.gov [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Arutinov, D.; Barbero, M. [University of Bonn, Bonn (Germany); Beccherle, R. [Istituto Nazionale di Fisica Nucleare Sezione di Genova, Genova (Italy); Dube, S.; Elledge, D. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Fleury, J. [Laboratoire de l' Accelerateur Lineaire, Orsay (France); Fougeron, D.; Gensolen, F. [Centre de Physique des Particules de Marseille, Marseille (France); Gnani, D. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Gromov, V. [Nationaal Instituut voor Subatomaire Fysica, Amsterdam (Netherlands); Hemperek, T.; Karagounis, M. [University of Bonn, Bonn (Germany); Kluit, R. [Nationaal Instituut voor Subatomaire Fysica, Amsterdam (Netherlands); Kruth, A. [University of Bonn, Bonn (Germany); Mekkaoui, A. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Menouni, M. [Centre de Physique des Particules de Marseille, Marseille (France); Schipper, J.-D. [Nationaal Instituut voor Subatomaire Fysica, Amsterdam (Netherlands)

    2011-04-21

    A new pixel readout integrated circuit denominated FE-I4 is being designed to meet the requirements of ATLAS experiment upgrades. It will be the largest readout IC produced to date for particle physics applications, filling the maximum allowed reticle area. This will significantly reduce the cost of future hybrid pixel detectors. In addition, FE-I4 will have smaller pixels and higher rate capability than the present generation of LHC pixel detectors. Design features are described along with simulation and test results, including low power and high rate readout architecture, mixed signal design strategy, and yield hardening.

  7. Small pixel pitch MCT IR-modules

    Science.gov (United States)

    Lutz, H.; Breiter, R.; Eich, D.; Figgemeier, H.; Fries, P.; Rutzinger, S.; Wendler, J.

    2016-05-01

    It is only some years ago, since VGA format detectors in 15μm pitch, manufactured with AIM's MCT n-on-p LPE standard technology, have been introduced to replace TV/4 format detector arrays as a system upgrade. In recent years a rapid increase in the demand for higher resolution, while preserving high thermal resolution, compactness and low power budget is observed. To satisfy these needs AIM has realized first prototypes of MWIR XGA format (1024x768) detector arrays in 10μm pitch. They fit in the same compact dewar as 640x512, 15μm pitch detector arrays. Therefore, they are best suited for system upgrade purposes to benefit from higher spatial resolution and keep cost on system level low. By combining pitch size reduction with recent development progress in the fields of miniature cryocoolers, short dewars and high operating temperatures the way ahead to ultra-compact high performance MWIR-modules is prepared. For cost reduction MBE grown MCT on commercially available GaAs substrates is introduced at AIM. Recently, 640x512, 15μm pitch FPAs, grown with MBE have successfully passed long-term high temperature storage tests as a crucial step towards serial production readiness level for use in future products. Pitch size reduction is not limited to arrays sensitive in the MWIR, but is of great interest for high performance LWIR or 3rd Gen solutions. Some applications such as rotorcraft pilotage require superior spatial resolution in a compact design to master severe weather conditions or degraded visual environment such as brown-out. For these applications AIM is developing both LWIR as well as dual band detector arrays in HD-format (1280x720) with 12μm pitch. This paper will present latest results in the development of detector arrays with small pitch sizes of 10μm and 12μm at AIM, together with their usage to realize compact cooled IR-modules.

  8. Design and Testing of a Prototype Pixellated CZT Detector and Shield for Hard X-Ray Astronomy

    OpenAIRE

    Bloser, P. F.; Grindlay, J.E.; Narita, T; Jenkins, J. A.

    1999-01-01

    We report on the design and laboratory testing of a prototype imaging CZT detector intended for balloon flight testing in April 2000. The detector tests several key techniques needed for the construction of large-area CZT arrays, as required for proposed hard X-ray astronomy missions. Two 10 mm x 10 mm x 5 mm CZT detectors, each with a 4 x 4 array of 1.9 mm pixels on a 2.5 mm pitch, will be mounted in a ``flip-chip'' fashion on a printed circuit board carrier card; the detectors will be place...

  9. Velocity Distribution Measurement Using Pixel-Pixel Cross Correlation of Electrical Tomography

    Institute of Scientific and Technical Information of China (English)

    DENGXiang; PENGLihui; YAODanya; ZHANGBaofen

    2004-01-01

    Electrical tomography (ET) provides a novel means of visualizing the internal behavior of twophase flow in industrial process. Using a dual-sensingplane Electrical resistance tomography (ERT) or Electrical capacitance tomography (ECT) system, the raw data of two different section images can be acquired synchronously and the two images reflecting the inner medium distribution respectively can also be reconstructed by using imaging algorithm. Further, the analysis of pixel-pixel cross correlation is able to be setup and the measurement of velocity distribution of two-phase flow could be achieved. The principle is described in the paper. The FFT algorithm for gray value computation and cross correlation function calculation is also introduced. Some experimental results of velocity distribution measurement using pixelpixel cross correlation in vertical slug flow are presented.

  10. Development and characterization of a TES optical imaging array for astrophysics applications

    Energy Technology Data Exchange (ETDEWEB)

    Burney, J. E-mail: burney@stanford.edu; Bay, T.J.; Brink, P.L.; Cabrera, B.; Castle, J.P.; Romani, R.W.; Tomada, A.; Nam, S.W.; Miller, A.J.; Martinis, J.; Wang, E.; Kenny, T.; Young, B.A

    2004-03-11

    Our research group has successfully developed photon detectors capable of both time-stamping and energy-resolving individual photons at very high rates in a wide band from the near-IR through optical and into the near-UV. We have fabricated 32-pixel arrays of these Transition-Edge Sensor (TES) devices and have mounted them in an adiabatic demagnetization refrigerator equipped with windows for direct imaging. We have characterized single pixel behavior; we have also begun operating multiple pixels simultaneously, starting the scaling process towards use of the full array. We emphasize the development of a metalized mask for our array that blocks photons from hitting the inter-pixel areas and reflects them onto the TESs. We also present calibration data on detector resolution, electronics noise, and optical alignment.

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

    Science.gov (United States)

    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

  12. Mechanical design and development of TES bolometer detector arrays for the Advanced ACTPol experiment

    CERN Document Server

    Ward, Jonathan T; Beall, James A; Choi, Steve K; Crowley, Kevin T; Devlin, Mark J; Duff, Shannon M; Gallardo, Patricio M; Henderson, Shawn W; Ho, Shuay-Pwu Patty; Hilton, Gene; Hubmayr, Johannes; Khavari, Niloufar; Klein, Jeffrey; Koopman, Brian J; Li, Dale; McMahon, Jeffrey; Mumby, Grace; Nati, Federico; Niemack, Michael D; Page, Lyman A; Salatino, Maria; Schillaci, Alessandro; Schmitt, Benjamin L; Simon, Sara M; Staggs, Suzanne T; Thornton, Robert; Ullom, Joel N; Vavagiakis, Eve M; Wollack, Edward J

    2016-01-01

    The next generation Advanced ACTPol (AdvACT) experiment is currently underway and will consist of four Transition Edge Sensor (TES) bolometer arrays, with three operating together, totaling ~5800 detectors on the sky. Building on experience gained with the ACTPol detector arrays, AdvACT will utilize various new technologies, including 150mm detector wafers equipped with multichroic pixels, allowing for a more densely packed focal plane. Each set of detectors includes a feedhorn array of stacked silicon wafers which form a spline profile leading to each pixel. This is then followed by a waveguide interface plate, detector wafer, back short cavity plate, and backshort cap. Each array is housed in a custom designed structure manufactured from high purity copper and then gold plated. In addition to the detector array assembly, the array package also encloses cryogenic readout electronics. We present the full mechanical design of the AdvACT high frequency (HF) detector array package along with a detailed look at t...

  13. Pixel detector modules performance for ATLAS IBL and future pixel detectors

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00355104; Pernegger, Heinz

    2015-11-06

    The ATLAS Detector is one of the four big particle physics experiments at CERN’s LHC. Its innermost tracking system consisted of the 3-Layer silicon Pixel Detector (~80M readout channels) in the first run (2010-2012). Over the past two years it was refurbished and equipped with new services as well as a new beam monitor. The major upgrade, however, was the Insertable B-Layer (IBL). It adds ~12M readout channels for improved vertexing, tracking robustness and b-tagging performance for the upcoming runs, before the high luminosity upgrade of the LHC will take place. This thesis covers two main aspects of Pixel detector performance studies: The main work was the planning, commissioning and operation of a test bench that meets the requirements of current pixel detector components. Each newly built ATLAS IBL stave was thoroughly tested, following a specifically developed procedure, and initially calibrated in that setup. A variety of production accompanying measurements as well as preliminary results after integ...

  14. Online data reduction with FPGA-based track reconstruction for the Belle II DEPFET pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Deschamps, Bruno; Wessel, Christian; Marinas, Carlos; Dingfelder, Jochen [Physikalisches Institut, Universitaet Bonn (Germany)

    2016-07-01

    The innermost two layers of the Belle II vertex detector at the KEK facility in Tsukuba, Japan, will be covered by high-granularity DEPFET pixel sensors (PXD). The large number of pixels leads to a maximum data rate of 256 Gbps, which has to be significantly reduced by the Data Acquisition System (DATCON). For the data reduction the hit information of the surrounding Silicon strip Vertex Detector (SVD) is utilized to define so-called Regions of Interest (ROI). Only hit information of the pixels located inside these ROIs are saved. The ROIs for the PXD are computed by reconstructing track segments from SVD data and extrapolation to the PXD. The goal is to achieve a data reduction of at least a factor of 10 with this ROI selection. All the necessary processing stages, the receiving, decoding and multiplexing of SVD data on 48 optical fibers, the track reconstruction and the definition of the ROIs, will be performed by the presented system. The planned hardware design is based on a distributed set of Advanced Mezzanine Cards (AMC) each equipped with a Field Programmable Gate Array (FPGA) and 4 optical transceivers. In this talk, the status and plans for the DATCON prototype and the FPGA-based tracking algorithm are introduced as well as the plans for their test in the upcoming test beam at DESY.

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

    Directory of Open Access Journals (Sweden)

    Tomislav Resetar

    2016-08-01

    Full Text Available 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.

  16. A 30 frames-per-second 18-million pixel image sensor for space applications

    Science.gov (United States)

    Lee, Paul P. K.; Newman, J. Daniel; Sacco, Andrew P.

    2011-06-01

    ITT Geospatial Systems has space-qualified a visible band interline Charge Coupled Device (CCD) image sensor with 18 million pixels developed using commercial technology. The sensor is comprised of an 4320 (H) x 4144 (V) array of 8 micron square pixels. With multiple analog outputs each operating at 20 MHz the sensor will support 30 frames per second continuous video capture. The pixel incorporates a pinned photodiode, vertical overflow drain and microlens to achieve low dark current, lag-free imaging with highspeed global electronic shutter at high quantum efficiency (QE). The vertical and horizontal CCD's are true two-phase designs which support an integrate-while-read operation. The sensor chip is mounted on an Aluminum Nitride co-fired ceramic package optimized for electrical signal integrity, thermal and optical stability. The architecture supports quadrant redundancy. The complete assembly has been space-qualified to a Technology Readiness Level (TRL) of 6 with Total Ionization Dose (TID) radiation testing at 25 Krad. The sensor exceeds 12-bit of dynamic range and 31% QE with 5 W of total power. The nonlinearity is measured to be 1.0% while the global non-uniformity is less than 2%. The low defect density of the CCD sensor allows high resolution video imaging in a space environment.

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

    Science.gov (United States)

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

    2016-08-15

    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.

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

    CERN Document Server

    Watt, J; Campbell, M; Mathieson, K; Mikulec, B; O'Shea, V; Passmore, M S; Schwarz, C; Smith, K M; Whitehill, C

    2001-01-01

    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 mu m thick SI-LEC GaAs detector patterned in a 64*64 array of 170 mu m pitch square pixels, bump-bonded to readout electronics operating in single photon counting mode. Intensity peaks in the powder diffraction pattern of KNbO/sub 3/ have been resolved and compared with results using the standard scintillator, and a PCD predecessor (the Omega 3). 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 Omega 3 by using a shutter based acquisition mode. A brief demonstration of the possibilities of the system for dental radiography and...

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

    Energy Technology Data Exchange (ETDEWEB)

    Watt, J. E-mail: j.watt@physics.gla.ac.uk; Bates, R.; Campbell, M.; Mathieson, K.; Mikulec, B.; O' Shea, V.; Passmore, M-S.; Schwarz, C.; Smith, K.M.; Whitehill, C

    2001-03-11

    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 {mu}m thick SI-LEC GaAs detector patterned in a 64x64 array of 170 {mu}m pitch square pixels, bump-bonded to readout electronics operating in single photon counting mode. Intensity peaks in the powder diffraction pattern of KNbO{sub 3} have been resolved and compared with results using the standard scintillator, and a PCD predecessor (the {omega}3). 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 {omega}3 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.

  20. Online data reduction with FPGA-based track reconstruction for the Belle II DEPFET pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Schnell, Michael; Deschamps, Bruno; Dingfelder, Jochen; Marinas, Carlos [University of Bonn (Germany); Collaboration: Belle II-Collaboration

    2015-07-01

    The innermost two layers of the Belle II vertex detector at the KEK facility in Tsukuba, Japan, will be covered by high-granularity DEPFET pixel sensors (PXD). The large number of pixels leads to a maximum data rate of 256 Gbps, which has to be significantly reduced by the Data Acquisition System. For the data reduction the hit information of the surrounding Silicon strip Vertex Detector (SVD) is utilized to define so-called Regions of Interest (ROI). Only hit information of the pixels located inside these ROIs are saved. The ROIs for the PXD are computed by reconstructing track segments from SVD data and extrapolation to the PXD. The goal is to achieve a data reduction of up to a factor of 10 with this ROI selection. All the necessary processing stages, the receiving, decoding and multiplexing of SVD data on 48 optical fibers, the track reconstruction and the definition of the ROIs, will be performed by the presented system. The planned hardware design is based on a distributed set of Advanced Mezzanine Cards (AMC) each equipped with a Field Programmable Gate Array (FPGA) and 4 optical transceivers. In this talk, the hardware and the FPGA-based tracking algorithm is introduced with some recent performance results from simulation and the latest test beam campaigns.

  1. EFFECT OF DATA TRUNCATION IN AN IMPLEMENTATION OF PIXEL CLUSTERING ON A CUSTOM COMPUTING MACHINE

    Energy Technology Data Exchange (ETDEWEB)

    M. LEESER; J. THEILER; ET AL

    2000-08-01

    We investigate the effect of truncating the precision of hyperspectral image data for the purpose of more efficiently segmenting the image using a variant of k-means clustering. We describe the implementation of the algorithm on field-programmable gate array (FPGA) hardware. Truncating the data to only a few bits per pixel in each spectral channel permits a more compact hardware design, enabling greater parallelism, and ultimately a more rapid execution. It also enables the storage of larger images in the onboard memory. In exchange for faster clustering, however, one trades off the quality of the produced segmentation. We find, however, that the clustering algorithm can tolerate considerable data truncation with little degradation in cluster quality. This robustness to truncated data can be extended by computing the cluster centers to a few more bits of precision than the data. Since there are so many more pixels than centers, the more aggressive data truncation leads to significant gains in the number of pixels that can be stored in memory and processed in hardware concurrently.

  2. X-ray Imaging Using a Hybrid Photon Counting GaAs Pixel Detector

    CERN Document Server

    Schwarz, C; Göppert, R; Heijne, Erik H M; Ludwig, J; Meddeler, G; Mikulec, B; Pernigotti, E; Rogalla, M; Runge, K; Smith, K M; Snoeys, W; Söldner-Rembold, S; Watt, J

    1999-01-01

    The performance of hybrid GaAs pixel detectors as X-ray imaging sensors were investigated at room temperature. These hybrids consist of 300 mu-m thick GaAs pixel detectors, flip-chip bonded to a CMOS Single Photon Counting Chip (PCC). This chip consists of a matrix of 64 x 64 identical square pixels (170 mu-m x 170 mu-m) and covers a total area of 1.2 cm**2. The electronics in each cell comprises a preamplifier, a discriminator with a 3-bit threshold adjust and a 15-bit counter. The detector is realized by an array of Schottky diodes processed on semi-insulating LEC-GaAs bulk material. An IV-charcteristic and a detector bias voltage scan showed that the detector can be operated with voltages around 200 V. Images of various objects were taken by using a standard X-ray tube for dental diagnostics. The signal to noise ratio (SNR) was also determined. The applications of these imaging systems range from medical applications like digital mammography or dental X-ray diagnostics to non destructive material testing (...

  3. Fully integrated system-on-chip for pixel-based 3D depth and scene mapping

    Science.gov (United States)

    Popp, Martin; De Coi, Beat; Thalmann, Markus; Gancarz, Radoslav; Ferrat, Pascal; Dürmüller, Martin; Britt, Florian; Annese, Marco; Ledergerber, Markus; Catregn, Gion-Pol

    2012-03-01

    We present for the first time a fully integrated system-on-chip (SoC) for pixel-based 3D range detection suited for commercial applications. It is based on the time-of-flight (ToF) principle, i.e. measuring the phase difference of a reflected pulse train. The product epc600 is fabricated using a dedicated process flow, called Espros Photonic CMOS. This integration makes it possible to achieve a Quantum Efficiency (QE) of >80% in the full wavelength band from 520nm up to 900nm as well as very high timing precision in the sub-ns range which is needed for exact detection of the phase delay. The SoC features 8x8 pixels and includes all necessary sub-components such as ToF pixel array, voltage generation and regulation, non-volatile memory for configuration, LED driver for active illumination, digital SPI interface for easy communication, column based 12bit ADC converters, PLL and digital data processing with temporary data storage. The system can be operated at up to 100 frames per second.

  4. Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging.

    Science.gov (United States)

    Esposito, M; Anaxagoras, T; Konstantinidis, A C; Zheng, Y; Speller, R D; Evans, P M; Allinson, N M; Wells, K

    2014-07-07

    Recently CMOS active pixels sensors (APSs) have become a valuable alternative to amorphous silicon and selenium flat panel imagers (FPIs) in bio-medical imaging applications. CMOS APSs can now be scaled up to the standard 20 cm diameter wafer size by means of a reticle stitching block process. However, despite wafer scale CMOS APS being monolithic, sources of non-uniformity of response and regional variations can persist representing a significant challenge for wafer scale sensor response. Non-uniformity of stitched sensors can arise from a number of factors related to the manufacturing process, including variation of amplification, variation between readout components, wafer defects and process variations across the wafer due to manufacturing processes. This paper reports on an investigation into the spatial non-uniformity and regional variations of a wafer scale stitched CMOS APS. For the first time a per-pixel analysis of the electro-optical performance of a wafer CMOS APS is presented, to address inhomogeneity issues arising from the stitching techniques used to manufacture wafer scale sensors. A complete model of the signal generation in the pixel array has been provided and proved capable of accounting for noise and gain variations across the pixel array. This novel analysis leads to readout noise and conversion gain being evaluated at pixel level, stitching block level and in regions of interest, resulting in a coefficient of variation ⩽1.9%. The uniformity of the image quality performance has been further investigated in a typical x-ray application, i.e. mammography, showing a uniformity in terms of CNR among the highest when compared with mammography detectors commonly used in clinical practice. Finally, in order to compare the detection capability of this novel APS with the technology currently used (i.e. FPIs), theoretical evaluation of the detection quantum efficiency (DQE) at zero-frequency has been performed, resulting in a higher DQE for this

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

    Science.gov (United States)

    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

  6. Monolithic LaBr3 : Ce crystals on silicon photomultiplier arrays for time-of-flight positron emission tomography

    NARCIS (Netherlands)

    Seifert, Stefan; van Dam, Herman T.; Huizenga, Jan; Vinke, Ruud; Dendooven, Peter; Löhner, Herbert; Schaart, Dennis R.

    2012-01-01

    Positron emission tomography detectors based on monolithic scintillation crystals exhibit good spatial and energy resolution, intrinsically provide depth-of-interaction information, have high gamma-photon capture efficiency, and may reduce the manufacturing costs compared to pixelated crystal arrays

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

    Science.gov (United States)

    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

  8. Achieving ultra-high temperatures with a resistive emitter array

    Science.gov (United States)

    Danielson, Tom; Franks, Greg; Holmes, Nicholas; LaVeigne, Joe; Matis, Greg; McHugh, Steve; Norton, Dennis; Vengel, Tony; Lannon, John; Goodwin, Scott

    2016-05-01

    The rapid development of very-large format infrared detector arrays has challenged the IR scene projector community to also develop larger-format infrared emitter arrays to support the testing of systems incorporating these detectors. In addition to larger formats, many scene projector users require much higher simulated temperatures than can be generated with current technology in order to fully evaluate the performance of their systems and associated processing algorithms. Under the Ultra High Temperature (UHT) development program, Santa Barbara Infrared Inc. (SBIR) is developing a new infrared scene projector architecture capable of producing both very large format (>1024 x 1024) resistive emitter arrays and improved emitter pixel technology capable of simulating very high apparent temperatures. During earlier phases of the program, SBIR demonstrated materials with MWIR apparent temperatures in excess of 1400 K. New emitter materials have subsequently been selected to produce pixels that achieve even higher apparent temperatures. Test results from pixels fabricated using the new material set will be presented and discussed. A 'scalable' Read In Integrated Circuit (RIIC) is also being developed under the same UHT program to drive the high temperature pixels. This RIIC will utilize through-silicon via (TSV) and Quilt Packaging (QP) technologies to allow seamless tiling of multiple chips to fabricate very large arrays, and thus overcome the yield limitations inherent in large-scale integrated circuits. Results of design verification testing of the completed RIIC will be presented and discussed.

  9. Architectural modeling of pixel readout chips Velopix and Timepix3

    NARCIS (Netherlands)

    Poikela, T.; Plosila, J.; Westerlund, T.; Buytaert, J.; Campbell, M.; Llopart, X.; Plackett, R.; Wyllie, K.; van Beuzekom, M.; Gromov, V.; Kluit, R.; Zappon, F.; Zivkovic, V.; Brezina, C.; Desch, K.; Fang, X.; Kruth, A.

    2012-01-01

    We examine two digital architectures for front end pixel readout chips, Velopix and Timepix3. These readout chips are developed for tracking detectors in future high energy physics experiments. They must incorporate local intelligence in pixels for time-over-threshold measurement and sparse readout.

  10. Novel integrated CMOS pixel structures for vertex detectors

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. The Phase-2 ATLAS ITk Pixel Upgrade

    CERN Document Server

    Benoit, Mathieu; The ATLAS collaboration

    2017-01-01

    The entire tracking system of the ATLAS experiment will be replaced during the LHC Phase II shutdown (foreseen to take place around 2025) by an all-silicon detector called the “ITk” (Inner Tracker). The innermost portion of the ITk will consist of a pixel detector with stave-like support structures in the most central region and ring-shaped supports in the endcap regions; there may also be novel inclined support structures in the barrel-endcap overlap regions. The new detector could have as much as 14 m2 of sensitive silicon. Support structures will be based on low mass, highly stable and highly thermally conductive carbon-based materials cooled by evaporative carbon dioxide. The ITk will be instrumented with new sensors and readout electronics to provide improved tracking performance compared to the current detector. All the module components must be performant enough and robust enough to cope with the expected high particle multiplicity and severe radiation background of the High-Luminosity LHC. Readout...

  12. CMB component separation in the pixel domain

    Science.gov (United States)

    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.

  13. SCUBA-2: The 10000 pixel bolometer camera on the James Clerk Maxwell Telescope

    CERN Document Server

    Holland, W S; Chapin, E L; Chrysostomou, A; Davis, G R; Dempsey, J T; Duncan, W D; Fich, M; Friberg, P; Halpern, M; Irwin, K D; Jenness, T; Kelly, B D; MacIntosh, M J; Robson, E I; Scott, D; Ade, P A R; Atad-Ettedgui, E; Berry, D S; Craig, S C; Gao, X; Gibb, A G; Hilton, G C; Hollister, M I; Kycia, J B; Lunney, D W; McGregor, H; Montgomery, D; Parkes, W; Tilanus, R P J; Ullom, J N; Walther, C A; Walton, A J; Woodcraft, A L; Amiri, M; Atkinson, D; Burger, B; Chuter, T; Coulson, I M; Doriese, W B; Dunare, C; Economou, F; Niemack, M D; Parsons, H A L; Reintsema, C D; Sibthorpe, B; Smail, I; Sudiwala, R; Thomas, H S

    2013-01-01

    SCUBA-2 is an innovative 10000 pixel bolometer camera operating at submillimetre wavelengths on the James Clerk Maxwell Telescope (JCMT). The camera has the capability to carry out wide-field surveys to unprecedented depths, addressing key questions relating to the origins of galaxies, stars and planets. With two imaging arrays working simultaneously in the atmospheric windows at 450 and 850 microns, the vast increase in pixel count means that SCUBA-2 maps the sky 100-150 times faster than the previous SCUBA instrument. In this paper we present an overview of the instrument, discuss the physical characteristics of the superconducting detector arrays, outline the observing modes and data acquisition, and present the early performance figures on the telescope. We also showcase the capabilities of the instrument via some early examples of the science SCUBA-2 has already undertaken. In February 2012, SCUBA-2 began a series of unique legacy surveys for the JCMT community. These surveys will take 2.5 years and the ...

  14. Performance assessment of a compressive sensing single-pixel imaging system

    Science.gov (United States)

    Du Bosq, Todd W.; Preece, Bradley L.

    2017-04-01

    Conventional sensors measure the light incident at each pixel in a focal plane array. Compressive sensing (CS) involves capturing a smaller number of unconventional measurements from the scene, and then using a companion process to recover the image. CS has the potential to acquire imagery with equivalent information content to a large format array while using smaller, cheaper, and lower bandwidth components. However, the benefits of CS do not come without compromise. The CS architecture chosen must effectively balance between physical considerations, reconstruction accuracy, and reconstruction speed to meet operational requirements. Performance modeling of CS imagers is challenging due to the complexity and nonlinearity of the system and reconstruction algorithm. To properly assess the value of such systems, it is necessary to fully characterize the image quality, including artifacts and sensitivity to noise. Imagery of a two-handheld object target set was collected using an shortwave infrared single-pixel CS camera for various ranges and number of processed measurements. Human perception experiments were performed to determine the identification performance within the trade space. The performance of the nonlinear CS camera was modeled by mapping the nonlinear degradations to an equivalent linear shift invariant model. Finally, the limitations of CS modeling techniques are discussed.

  15. Integrated array of 2-mum antimonide-based single-photon counting devices

    NARCIS (Netherlands)

    Diagne, M.A.; Greszik, M.; Duerr, E.K.; Zayhowski, J.J.; Manfra, M.J.; Bailey, R.J.; Donnelly, J.P.; Turner, G.W.

    2011-01-01

    A 32x32 Sb-based Geiger-mode (GM) avalanche photodiode array, operating at 2 mum with three-dimensional imaging capability, is presented. The array is interfaced with a ROIC (readout integrated circuit) in which each pixel can detect a photon and record the arrival time. The hybridized unit for the

  16. Heat dissipation analysis of bendable AlGaInP micro-LED arrays

    Science.gov (United States)

    Fang, Shiwei; Wang, Weibiao; Liang, Jingqiu; Liang, Zhongzhu; Qin, Yuxin; Lv, Jinguang

    2017-01-01

    A strategy for fabricating bendable AlGaInP light emitting diode (LED) arrays is presented in this paper. Sample LED arrays with 8 × 8 pixels were fabricated and subjected to bending. Bending only weakly affected the light output power and the current-voltage characteristics of the arrays. LED arrays suffer from a thermal problem owing to the energy loss during the electrical-to-optical energy conversion. We have designed a three-dimensional heat conduction model for analyzing the effect of the polymer substrate, the configuration of pixels, and the micro-structure on heat dissipation in bendable LED arrays. Thermal conductivity of the polymer substrate critically affected the heat dissipation, suggesting that the substrate thickness should be in the 500-1000 μ m range. A larger pixel distance yielded more distributed heat sources and more uniform temperature distribution. Micro-structured polymer substrates yielded lower temperature, especially for the fins array micro-structure. Based on enhancing the polymer's thermal conductivity and distributing LED pixels, optimizing the substrate's micro-structure is an effective method to improve heat dissipation in bendable LED arrays. Optimized heat dissipation could effectively reduce heat accumulation in LED arrays and alleviate an increase in the junction temperature, allowing to increase the output power of the device.

  17. Giga-pixel lensfree holographic microscopy and tomography using color image sensors.

    Directory of Open Access Journals (Sweden)

    Serhan O Isikman

    Full Text Available We report Giga-pixel lensfree holographic microscopy and tomography using color sensor-arrays such as CMOS imagers that exhibit Bayer color filter patterns. Without physically removing these color filters coated on the sensor chip, we synthesize pixel super-resolved lensfree holograms, which are then reconstructed to achieve ~350 nm lateral resolution, corresponding to a numerical aperture of ~0.8, across a field-of-view of ~20.5 mm(2. This constitutes a digital image with ~0.7 Billion effective pixels in both amplitude and phase channels (i.e., ~1.4 Giga-pixels total. Furthermore, by changing the illumination angle (e.g., ± 50° and scanning a partially-coherent light source across two orthogonal axes, super-resolved images of the same specimen from different viewing angles are created, which are then digitally combined to synthesize tomographic images of the object. Using this dual-axis lensfree tomographic imager running on a color sensor-chip, we achieve a 3D spatial resolution of ~0.35 µm × 0.35 µm × ~2 µm, in x, y and z, respectively, creating an effective voxel size of ~0.03 µm(3 across a sample volume of ~5 mm(3, which is equivalent to >150 Billion voxels. We demonstrate the proof-of-concept of this lensfree optical tomographic microscopy platform on a color CMOS image sensor by creating tomograms of micro-particles as well as a wild-type C. elegans nematode.

  18. Hard x-ray response of pixellated CdZnTe detectors

    Science.gov (United States)

    Abbene, L.; Del Sordo, S.; Caroli, E.; Gerardi, G.; Raso, G.; Caccia, S.; Bertuccio, G.

    2009-06-01

    In recent years, the development of cadmium zinc telluride (CdZnTe) detectors for x-ray and gamma ray spectrometry has grown rapidly. The good room temperature performance and the high spatial resolution of pixellated CdZnTe detectors make them very attractive in space-borne x-ray astronomy, mainly as focal plane detectors for the new generation of hard x-ray focusing telescopes. In this work, we investigated on the spectroscopic performance of two pixellated CdZnTe detectors coupled with a custom low noise and low power readout application specific integrated circuit (ASIC). The detectors (10×10×1 and 10×10×2 mm3 single crystals) have an anode layout based on an array of 256 pixels with a geometric pitch of 0.5 mm. The ASIC, fabricated in 0.8 μm BiCMOS technology, is equipped with eight independent channels (preamplifier and shaper) and characterized by low power consumption (0.5 mW/channel) and low noise (150-500 electrons rms). The spectroscopic results point out the good energy resolution of both detectors at room temperature [5.8% full width at half maximum (FWHM) at 59.5 keV for the 1 mm thick detector; 5.5% FWHM at 59.5 keV for the 2 mm thick detector) and low tailing in the measured spectra, confirming the single charge carrier sensing properties of the CdZnTe detectors equipped with a pixellated anode layout. Temperature measurements show optimum performance of the system (detector and electronics) at T =10 °C and performance degradation at lower temperatures. The detectors and the ASIC were developed by our collaboration as two small focal plane detector prototypes for hard x-ray multilayer telescopes operating in the 20-70 keV energy range.

  19. Characterization of active CMOS sensors for capacitively coupled pixel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Hirono, Toko; Gonella, Laura; Janssen, Jens; Hemperek, Tomasz; Huegging, Fabian; Krueger, Hans; Wermes, Norbert [Institute of Physics, University of Bonn (Germany); Peric, Ivan [Institut fuer Prozessdatenverarbeitung und Elektronik, Karlsruher Institut fuer Technologie, Karlsruhe (Germany)

    2015-07-01

    Active CMOS pixel sensor is one of the most attractive candidates for detectors of upcoming particle physics experiments. In contrast to conventional sensors of hybrid detectors, signal processing circuit can be integrated in the active CMOS sensor. The characterization and optimization of the pixel circuit are indispensable to obtain a good performance from the sensors. The prototype chips of the active CMOS sensor were fabricated in the AMS 180nm and L-Foundry 150 nm CMOS processes, respectively a high voltage and high resistivity technology. Both chips have a charge sensitive amplifier and a comparator in each pixel. The chips are designed to be glued to the FEI4 pixel readout chip. The signals from 3 pixels of the prototype chips are capacitively coupled to the FEI4 input pads. We have performed lab tests and test beams to characterize the prototypes. In this presentation, the measurement results of the active CMOS prototype sensors are shown.

  20. Research on ionospheric tomography based on variable pixel height

    Science.gov (United States)

    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.

  1. Status of the CMS Phase I pixel detector upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Spannagel, S., E-mail: simon.spannagel@desy.de

    2016-09-21

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

  2. Development of radiation hardened pixel sensors for charged particle detection

    CERN Document Server

    Koziel, Michal

    2014-01-01

    CMOS Pixel Sensors are being developed since a few years to equip vertex detectors for future high-energy physics experiments with the crucial advantages of a low material budget and low production costs. The features simultaneously required are a short readout time, high granularity and high tolerance to radiation. This thesis mainly focuses on the radiation tolerance studies. To achieve the targeted readout time (tens of microseconds), the sensor pixel readout was organized in parallel columns restricting in addition the readout to pixels that had collected the signal charge. The pixels became then more complex, and consequently more sensitive to radiation. Different in-pixel architectures were studied and it was concluded that the tolerance to ionizing radiation was limited to 300 krad with the 0.35- m fabrication process currently used, while the targeted value was several Mrad. Improving this situation calls for implementation of the sensors in processes with a smaller feature size which naturally imp...

  3. DEPFET--a pixel device with integrated amplification

    CERN Document Server

    Neeser, W; Buchholz, P; Fischer, P; Holl, P; Kemmer, J; Klein, P; Koch, H; Löcker, M; Lutz, Gerhard; Matthäy, H; Strüder, L; Trimpl, M; Ulrici, J; Wermes, N

    2002-01-01

    In the DEPFET pixel concept, the absorbed radiation directly modulates the channel current of a p-JFET transistor being integrated into a fully depleted high ohmic silicon substrate in every pixel cell, offering very low noise operation at room temperature. Hence, DEPFET pixels open new possibilities in biomedical applications, but also have a potential in particle physics and astrophysics. Second prototype 50 mu mx50 mu m single pixels as well as large (64x64) DEPFET matrices have been successfully produced and operated confirming the low noise behavior (12e). Device studies as well as a full DEPFET pixel Bioscope system to be used in real-time digital autoradiography with excellent spatial and energy resolution for X-rays are presented.

  4. DC-DC powering for the CMS pixel upgrade

    Science.gov (United States)

    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.

  5. DC-DC Powering for the CMS Pixel Upgrade

    CERN Document Server

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

    2013-01-01

    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 and 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 to24 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.

  6. DC–DC powering for the CMS pixel upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Feld, Lutz, E-mail: Lutz.Feld@rwth-aachen.de; Fleck, Martin; Friedrichs, Marcel; Hensch, Richard; Karpinski, Waclaw; Klein, Katja; Rittich, David; Sammet, Jan; Wlochal, Michael

    2013-12-21

    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 and 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. Neural network based cluster creation in the ATLAS Pixel Detector

    CERN Document Server

    Andreazza, A; The ATLAS collaboration

    2012-01-01

    The read-out from individual pixels on planar semi-conductor sensors are grouped into clusters to reconstruct the location where a charged particle passed through the sensor. The resolution given by individual pixel sizes is significantly improved by using the information from the charge sharing be- tween pixels. Such analog cluster creation techniques have been used by the ATLAS experiment for many years to obtain an excellent performance. How- ever, in dense environments, such as those inside high-energy jets, clusters have an increased probability of merging the charge deposited by multiple particles. Recently, a neural network based algorithm which estimates both the cluster position and whether a cluster should be split has been developed for the ATLAS Pixel Detector. The algorithm significantly reduces ambigui- ties in the assignment of pixel detector measurement to tracks and improves the position accuracy with respect to standard techniques by taking into account the 2-dimensional charge distribution.

  8. Sub-pixel mapping method based on BP neural network

    Institute of Scientific and Technical Information of China (English)

    LI Jiao; WANG Li-guo; ZHANG Ye; GU Yan-feng

    2009-01-01

    A new sub-pixel mapping method based on BP neural network is proposed in order to determine the spatial distribution of class components in each mixed pixel. The network was used to train a model that describes the relationship between spatial distribution of target components in mixed pixel and its neighboring information. Then the sub-pixel scaled target could be predicted by the trained model. In order to improve the performance of BP network, BP learning algorithm with momentum was employed. The experiments were conducted both on synthetic images and on hyperspectral imagery (HSI). The results prove that this method is capable of estimating land covers fairly accurately and has a great superiority over some other sub-pixel mapping methods in terms of computational complexity.

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

    CERN Document Server

    Stramaglia, Maria Elena; The ATLAS collaboration

    2015-01-01

    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 read-out hardware to support high bandwidth for data readout and calibration. The hardware is supported by an embedded software stack running on the read-out boards. The same boards will be used to upgrade the read-out bandwidth for the two outermost layers of the ATLAS Pixel Barrel (54 million pixels). We present the IBL read-out 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.

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

    CERN Document Server

    Stramaglia, Maria Elena; The ATLAS collaboration

    2015-01-01

    In 2014, the Pixel Detector of the ATLAS experiment was extended by about 12 million pixels with the installation of the Insertable B-Layer (IBL). Data-taking and tuning procedures have been implemented by employing newly designed read-out hardware, which supports the full detector bandwidth even for calibration. The hardware is supported by an embedded software stack running on the read-out boards. The same boards will be used to upgrade the read-out bandwidth for the two outermost layers of the ATLAS Pixel Barrel (54 million pixels). We present the IBL read-out 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. Near Future Upgrades for the CMS Pixel Detector

    CERN Document Server

    Kumar, Ashish

    2015-01-01

    The silicon pixel detector is the innermost component of the CMS tracking system, providing high precision space point measurements of charged particle trajectories. The current pixel detector is designed to operate at a maximum luminosity of $1\\times10^{34}cm^{-2}s^{-1}$. Before 2018 the instantaneous luminosity of the LHC is expected to reach $2\\times10^{34}cm^{-2}s^{-1}$, which will significantly increase the number of interactions per bunch crossing. The performance of the current pixel detector in such high occupancy environment will be degraded due to substantial data-loss and effects of radiation damage of sensors, built up over the operational period. In order to maintain or exceed its current performance, the CMS pixel detector will be replaced by a new lightweight system with additional detection layers, better acceptance and improved readout electronics. The upgraded pixel detector will provide improved track and vertex reconstruction, standalone tracking capabilities, as well as identification of ...

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

    Science.gov (United States)

    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.

  13. Test of CZT Detectors with Different Pixel Pitches and Thicknesses

    CERN Document Server

    Li, Qiang; Jung, Ira; Groza, Michael; Dowkontt, Paul; Bose, Richard; Simburger, Garry; Burger, Arnold; Krawczynski, Henric

    2007-01-01

    The Modified Horizontal Bridgman (MHB) process produces Cadmium Zinc Telluride (CZT) crystals with high yield and excellent homogeneity. Various groups,including our own, previously reported on the test of 2x2x0.5 cm3 MHB CZT detectors grown by the company Orbotech and read out with 8x8 pixels. In this contribution, we describe the optimization of the photolithographic process used for contacting the CZT detector with pixel contacts. The optimized process gives a high yield of good pixels down to pixel diameters/pitches of 50 microns. Furthermore, we discuss the performance of 0.5 cm and 0.75 cm thick detectors contacted with 64 and 225 pixel read out with the RENA-3 ASICs from the company NOVA R&D.

  14. Status of the CMS Phase I Pixel Detector Upgrade

    CERN Document Server

    AUTHOR|(CDS)2083994

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Development of Fuses for Protection of Geiger-Mode Avalanche Photodiode Arrays

    Science.gov (United States)

    Grzesik, Michael; Bailey, Robert; Mahan, Joe; Ampe, Jim

    2015-11-01

    Current-limiting fuses composed of Ti/Al/Ni were developed for use in Geiger-mode avalanche photodiode arrays for each individual pixel in the array. The fuses were designed to burn out at ˜4.5 × 10-3 A and maintain post-burnout leakage currents less than 10-7 A at 70 V sustained for several minutes. Experimental fuse data are presented and successful incorporation of the fuses into a 256 × 64 pixel InP-based Geiger-mode avalanche photodiode array is reported.

  17. From Single Pixels to Many Megapixels: Progress in Astronomical Infrared Imaging from Space-borne Telescopes

    Science.gov (United States)

    Pipher, Judith

    2017-01-01

    In the 1960s, rocket infrared astronomy was in its infancy. The Cornell group planned a succession of rocket launches of a small cryogenically cooled telescope above much of the atmosphere. Cornell graduate students were tasked with hand-making single pixel detectors for the focal plane at wavelengths ranging from ~5 microns to just short of 1 mm. “Images” could only be constructed from scans of objects such as HII regions/giant molecular clouds, the galactic center, and of diffuse radiation from the various IR backgrounds. IRAS and COBE, followed by the KAO utilized ever more sensitive single IR detectors, and revolutionized our understanding of the Universe. The first IR arrays came onto the scene in the early 1970s - and in 1983 several experiments for the space mission SIRTF (later named Spitzer Space Telescope following launch 20 years later) were selected, all boasting (relatively small) arrays. Europe’s ISO and Herschel also employed arrays to good advantage, as has SOFIA, and now, many-megapixel IR arrays are sufficiently well-developed for upcoming space missions.

  18. ANALYSIS OF MULTIPATH PIXELS IN SAR IMAGES

    Directory of Open Access Journals (Sweden)

    J. W. Zhao

    2016-06-01

    Full Text Available 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, permittivitywhich 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.

  19. First Light with a 67-Million-Pixel WFI Camera

    Science.gov (United States)

    1999-01-01

    the currently planned, new wide-field telescopes. The FIERA CCD controller The entire detector array of the WFI can be read out in only 27 seconds. Since one WFI image contains 0.14 Gbytes of data, this corresponds to the reading of a book at a rate of almost 1000 pages per second! Even for the most powerful PC's presently available, this can be a real challenge. However, much more remarkable is that FIERA , the high-tech CCD controller developed by ESO engineers, sustains this speed without adding noise or artifacts that exceed the extremely faint signal from the night-sky background on a moonless night at a completely dark site such as La Silla. In addition to the eight large CCD's of the mosaic, FIERA simultaneously commands a ninth CCD of the same type in which a small window centered on a bright star is read out continuously, up to 2 times every second. The fast-rate measurement of the instantaneous position of the star enables the telescope control system to track very accurately the apparent motion of the observed field in the sky so that the images remain perfectly sharp, even during long exposures. Future survey work at ESO In terms of bytes, it is expected that the WFI alone will acquire more observational data than all the rest of the La Silla Observatory and the UT1 of the VLT on Paranal together! This impressively illustrates the ever-accelerating pace at which astronomical facilities are developing. In the meantime, a Dutch/German/Italian consortium is preparing for the construction of the successor to WFI camera. The OmegaCam will have no less than 16,000 x 16,000 pixels and the field-of-view is four times as large, one square degree. It will be attached to the 2.6-m VLT Survey Telescope (VST) to be installed jointly by OAC and ESO on Paranal at the end of the year 2001. Note: [1]: Some technical details of the new camera: The WFI field-of-view measures 0.54 x 0.54 deg 2 (32.4 x 32.4 arcmin 2 ) and the image scale is 0.24 arcsec/pixel. An advanced

  20. Performance limits of a single photon counting pixel system

    Science.gov (United States)

    Chmeissani, M.; Mikulec, B.

    2001-03-01

    X-ray imaging using hybrid pixel detectors in single photon counting mode is a relatively recent and exciting development. The photon counting mode implies that each pixel has a threshold in energy above which a hit is recorded. Sharing of charge between adjacent pixels would therefore lead to a loss of registered hits and for medical imaging applications to a higher patient dose. This explains why the demand for high spatial resolution and consequently small pixel sizes (<100 μm) motivates the Medipix2 collaboration to study the effects of charge sharing between pixels on system performance. Two different simulation codes are used to simulate the energy loss inside the detector and the charge transport towards the pixel electrodes. The largest contribution to the lateral spreading of charge comes from diffusion and can result in a considerable loss of detection efficiency in photon counting systems for small pixel sizes. The Medipix2 collaboration consists of groups from Barcelona, Cagliari, CEA/Leti DEIN, CERN, Freiburg, Glasgow, Mitthögskolan, Napoli, NIKHEF, MRC lab Cambridge, Pisa, Prague and Sassari.