WorldWideScience

Sample records for rate imaging detector

  1. Novel Neutron Detector for High Rate Imaging Applications

    Energy Technology Data Exchange (ETDEWEB)

    Lacy, Jeffrey, L.

    2004-08-27

    The Phase II period performance was May 30, 2002 through May 29, 2004. This development effort was successfully completed within the period and budget allotted. The proposed design was successfully fabricated from B{sub 4}C-coated aluminum and copper film, slit and wound to form 4 mm diameter straws, cut to 100 cm in length, and threaded with resistive anode wires (20 {micro}m in diameter). This paper reports testing done with two 50-straw detector modules at the reactor of the Nuclear Science Center at Texas A&M University (TAMU NSC).

  2. Ion-ion coincidence imaging at high event rate using an in-vacuum pixel detector

    Science.gov (United States)

    Long, Jingming; Furch, Federico J.; Durá, Judith; Tremsin, Anton S.; Vallerga, John; Schulz, Claus Peter; Rouzée, Arnaud; Vrakking, Marc J. J.

    2017-07-01

    A new ion-ion coincidence imaging spectrometer based on a pixelated complementary metal-oxide-semiconductor detector has been developed for the investigation of molecular ionization and fragmentation processes in strong laser fields. Used as a part of a velocity map imaging spectrometer, the detection system is comprised of a set of microchannel plates and a Timepix detector. A fast time-to-digital converter (TDC) is used to enhance the ion time-of-flight resolution by correlating timestamps registered separately by the Timepix detector and the TDC. In addition, sub-pixel spatial resolution (algorithm. This performance is achieved while retaining a high event rate (104 per s). The spectrometer was characterized and used in a proof-of-principle experiment on strong field dissociative double ionization of carbon dioxide molecules (CO2), using a 400 kHz repetition rate laser system. The experimental results demonstrate that the spectrometer can detect multiple ions in coincidence, making it a valuable tool for studying the fragmentation dynamics of molecules in strong laser fields.

  3. Characterization of an ultraviolet imaging detector with high event rate ROIC (HEROIC) readout

    Science.gov (United States)

    Nell, Nicholas; France, Kevin; Harwit, Alex; Bradley, Scott; Franka, Steve; Freymiller, Ed; Ebbets, Dennis

    2016-07-01

    We present characterization results from a photon counting imaging detector consisting of one microchannel plate (MCP) and an array of two readout integrated circuits (ROIC) that record photon position. The ROICs used in the position readout are the high event rate ROIC (HEROIC) devices designed to handle event rates up to 1 MHz per pixel, recently developed by the Ball Aerospace and Technologies Corporation in collaboration with the University of Colorado. An opaque cesium iodide (CsI) photocathode sensitive in the far-ultraviolet (FUV; 122-200 nm), is deposited on the upper surface of the MCP. The detector is characterized in a chamber developed by CU Boulder that is capable of illumination with vacuum-ultraviolet (VUV) monochromatic light and measurement of absolute ux with a calibrated photodiode. Testing includes investigation of the effects of adjustment of internal settings of the HEROIC devices including charge threshold, gain, and amplifier bias. The detector response to high count rates is tested. We report initial results including background, uniformity, and quantum detection efficiency (QDE) as a function of wavelength.

  4. Noiseless imaging detector for adaptive optics with kHz frame rates

    CERN Document Server

    Vallerga, J V; Mikulec, Bettina; Tremsin, A; Clark, Allan G; Siegmund, O H W; CERN. Geneva

    2004-01-01

    A new hybrid optical detector is described that has many of the attributes desired for the next generation AO wavefront sensors. The detector consists of a proximity focused MCP read out by four multi-pixel application specific integrated circuit (ASIC) chips developed at CERN (â€ワMedipix2”) with individual pixels that amplify, discriminate and count input events. The detector has 512 x 512 pixels, zero readout noise (photon counting) and can be read out at 1 kHz frame rates. The Medipix2 readout chips can be electronically shuttered down to a temporal window of a few microseconds with an accuracy of 10 nanoseconds. When used in a Shack-Hartman style wavefront sensor, it should be able to centroid approximately 5000 spots using 7 x 7 pixel sub-apertures resulting in very linear, off-null error correction terms. The quantum efficiency depends on the optical photocathode chosen for the bandpass of interest. A three year development effort for this detector technology has just been funded as part of the...

  5. 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 ...

  6. Workshops on radiation imaging detectors

    Energy Technology Data Exchange (ETDEWEB)

    Sochinskii, N.V.; Sun, G.C.; Kostamo, P.; Silenas, A.; Saynatjoki, A.; Grant, J.; Owens, A.; Kozorezov, A.G.; Noschis, E.; Van Eijk, C.; Nagarkar, V.; Sekiya, H.; Pribat, D.; Campbell, M.; Lundgren, J.; Arques, M.; Gabrielli, A.; Padmore, H.; Maiorino, M.; Volpert, M.; Lebrun, F.; Van der Putten, S.; Pickford, A.; Barnsley, R.; Anton, M.E.G.; Mitschke, M.; Gros d' Aillon, E.; Frojdh, C.; Norlin, B.; Marchal, J.; Quattrocchi, M.; Stohr, U.; Bethke, K.; Bronnimann, C.H.; Pouvesle, J.M.; Hoheisel, M.; Clemens, J.C.; Gallin-Martel, M.L.; Bergamaschi, A.; Redondo-Fernandez, I.; Gal, O.; Kwiatowski, K.; Montesi, M.C.; Smith, K

    2005-07-01

    This document gathers the transparencies that were presented at the international workshop on radiation imaging detectors. 9 sessions were organized: 1) materials for detectors and detector structure, 2) front end electronics, 3) interconnected technologies, 4) space, fusion applications, 5) the physics of detection, 6) industrial applications, 7) synchrotron radiation, 8) X-ray sources, and 9) medical and other applications.

  7. Transmission diamond imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Smedley, John, E-mail: smedley@bnl.gov; Pinelli, Don; Gaoweia, Mengjia [Brookhaven National Laboratory, Upton, NY (United States); Muller, Erik; Ding, Wenxiang; Zhou, Tianyi [Stony Brook University, Stony Brook, NY (United States); Bohon, Jen [Case Center for Synchrotron Biosciences, Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH (United States)

    2016-07-27

    Many modern synchrotron techniques are trending toward use of high flux beams and/or beams which require enhanced stability and precise understanding of beam position and intensity from the front end of the beamline all the way to the sample. For high flux beams, major challenges include heat load management in optics (including the vacuum windows) and a mechanism of real-time volumetric measurement of beam properties such as flux, position, and morphology. For beam stability in these environments, feedback from such measurements directly to control systems for optical elements or to sample positioning stages would be invaluable. To address these challenges, we are developing diamond-based instrumented vacuum windows with integrated volumetric x-ray intensity, beam profile and beam-position monitoring capabilities. A 50 µm thick single crystal diamond has been lithographically patterned to produce 60 µm pixels, creating a >1kilopixel free-standing transmission imaging detector. This device, coupled with a custom, FPGA-based readout, has been used to image both white and monochromatic x-ray beams and capture the last x-ray photons at the National Synchrotron Light Source (NSLS). This technology will form the basis for the instrumented end-station window of the x-ray footprinting beamline (XFP) at NSLS-II.

  8. Electron imaging with an EBSD detector

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Stuart I., E-mail: stuart.wright@ametek.com [EDAX, 392 East 12300 South, Suite H, Draper, UT 84020 (United States); Nowell, Matthew M. [EDAX, 392 East 12300 South, Suite H, Draper, UT 84020 (United States); Kloe, René de [EDAX, Ringbaan Noord 103, 5046 AA Tilburg (Netherlands); Camus, Patrick; Rampton, Travis [EDAX, 91 McKee Drive, Mahwah, NJ 07430 (United States)

    2015-01-15

    Electron Backscatter Diffraction (EBSD) has proven to be a useful tool for characterizing the crystallographic orientation aspects of microstructures at length scales ranging from tens of nanometers to millimeters in the scanning electron microscope (SEM). With the advent of high-speed digital cameras for EBSD use, it has become practical to use the EBSD detector as an imaging device similar to a backscatter (or forward-scatter) detector. Using the EBSD detector in this manner enables images exhibiting topographic, atomic density and orientation contrast to be obtained at rates similar to slow scanning in the conventional SEM manner. The high-speed acquisition is achieved through extreme binning of the camera—enough to result in a 5×5 pixel pattern. At such high binning, the captured patterns are not suitable for indexing. However, no indexing is required for using the detector as an imaging device. Rather, a 5×5 array of images is formed by essentially using each pixel in the 5×5 pixel pattern as an individual scattered electron detector. The images can also be formed at traditional EBSD scanning rates by recording the image data during a scan or can also be formed through post-processing of patterns recorded at each point in the scan. Such images lend themselves to correlative analysis of image data with the usual orientation data provided by and with chemical data obtained simultaneously via X-Ray Energy Dispersive Spectroscopy (XEDS). - Highlights: • The EBSD detector can be used as a set of multiple electron scattering detectors for microstructural imaging. • Extreme binning enables the use of the EBSD detector as an imaging detector with image collection times similar to slow scan SEM imaging. • Using an EBSD detector as an imaging detector provides images showing topographic, atomic density and orientation contrast or a mix of all three. • These images can collect prior to performing a scan, during a scan or through post-processing of patterns

  9. On Recall Rate of Interest Point Detectors

    DEFF Research Database (Denmark)

    Aanæs, Henrik; Dahl, Anders Lindbjerg; Pedersen, Kim Steenstrup

    2010-01-01

    in relation to the number of interest points, the recall rate as a function of camera position and light variation, and the sensitivity relative to model parameter change. The overall conclusion is that the Harris corner detector has a very high recall rate, but is sensitive to change in scale. The Hessian......In this paper we provide a method for evaluating interest point detectors independently of image descriptors. This is possible because we have compiled a unique data set enabling us to determine if common interest points are found. The data contains 60 scenes of a wide range of object types......, and for each scene we have 119 precisely located camera positions obtained from a camera mounted on an industrial robot arm. The scene surfaces have been scanned using structured light, providing precise 3D ground truth. We have investigated a number of the most popular interest point detectors. This is done...

  10. X-ray imaging detectors for synchrotron and XFEL sources

    OpenAIRE

    Takaki Hatsui; Heinz Graafsma

    2015-01-01

    Current trends for X-ray imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve their performance, especially for higher spatial resolution at higher count rates with higher frame rates. Recent developments for X-ray free-electron laser (XFEL) experiments provide high-frame-rate integrating detectors with both high sensitivit...

  11. Research on particle imaging detectors

    CERN Document Server

    1995-01-01

    Much instrumentation has been developed for imaging the trajectories of elementary particles produced in high energy collisions. Since 1968, gaseous detectors, beginning with multiwire chambers and drift chambers, have been used for the visualisation of particle trajectories and the imaging of X-rays, neutrons, hard gamma rays, beta rays and ultraviolet photons. This book commemorates the groundbreaking research leading to the evolution of such detectors carried out at CERN by Georges Charpak, Nobel Prizewinner for Physics in 1992. Besides collecting his key papers, the book also includes original linking commentary which sets his work in the context of other worldwide research.

  12. Ultraviolet imaging detectors for the GOLD mission

    Science.gov (United States)

    Siegmund, O. H. W.; McPhate, J.; Curtis, T.; Jelinsky, S.; Vallerga, J. V.; Hull, J.; Tedesco, J.

    2016-07-01

    The GOLD mission is a NASA Explorer class ultraviolet Earth observing spectroscopy instrument that will be flown on a telecommunications satellite in geostationary orbit in 2018. Microchannel plate detectors operating in the 132 nm to 162 nm FUV bandpass with 2D imaging cross delay line readouts and electronics have been built for each of the two spectrometer channels for GOLD. The detectors are "open face" with CsI photocathodes, providing 30% efficiency at 130.4 nm and 15% efficiency at 160.8 nm. These detectors with their position encoding electronics provide 600 x 500 FWHM resolution elements and are photon counting, with event handling rates of > 200 KHz. The operational details of the detectors and their performance are discussed.

  13. X-ray imaging detectors for synchrotron and XFEL sources

    Directory of Open Access Journals (Sweden)

    Takaki Hatsui

    2015-05-01

    Full Text Available Current trends for X-ray imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve their performance, especially for higher spatial resolution at higher count rates with higher frame rates. Recent developments for X-ray free-electron laser (XFEL experiments provide high-frame-rate integrating detectors with both high sensitivity and high peak signal. Similar performance improvements are sought in monolithic detectors. The monolithic approach also offers a lower noise floor, which is required for the detection of soft X-ray photons. The link between technology development and detector performance is described briefly in the context of potential future capabilities for X-ray imaging detectors.

  14. X-ray imaging detectors for synchrotron and XFEL sources.

    Science.gov (United States)

    Hatsui, Takaki; Graafsma, Heinz

    2015-05-01

    Current trends for X-ray imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve their performance, especially for higher spatial resolution at higher count rates with higher frame rates. Recent developments for X-ray free-electron laser (XFEL) experiments provide high-frame-rate integrating detectors with both high sensitivity and high peak signal. Similar performance improvements are sought in monolithic detectors. The monolithic approach also offers a lower noise floor, which is required for the detection of soft X-ray photons. The link between technology development and detector performance is described briefly in the context of potential future capabilities for X-ray imaging detectors.

  15. HIgh Rate X-ray Fluorescence Detector

    Energy Technology Data Exchange (ETDEWEB)

    Grudberg, Peter Matthew [XIA LLC

    2013-04-30

    The purpose of this project was to develop a compact, modular multi-channel x-ray detector with integrated electronics. This detector, based upon emerging silicon drift detector (SDD) technology, will be capable of high data rate operation superior to the current state of the art offered by high purity germanium (HPGe) detectors, without the need for liquid nitrogen. In addition, by integrating the processing electronics inside the detector housing, the detector performance will be much less affected by the typically noisy electrical environment of a synchrotron hutch, and will also be much more compact than current systems, which can include a detector involving a large LN2 dewar and multiple racks of electronics. The combined detector/processor system is designed to match or exceed the performance and features of currently available detector systems, at a lower cost and with more ease of use due to the small size of the detector. In addition, the detector system is designed to be modular, so a small system might just have one detector module, while a larger system can have many you can start with one detector module, and add more as needs grow and budget allows. The modular nature also serves to simplify repair. In large part, we were successful in achieving our goals. We did develop a very high performance, large area multi-channel SDD detector, packaged with all associated electronics, which is easy to use and requires minimal external support (a simple power supply module and a closed-loop water cooling system). However, we did fall short of some of our stated goals. We had intended to base the detector on modular, large-area detectors from Ketek GmbH in Munich, Germany; however, these were not available in a suitable time frame for this project, so we worked instead with pnDetector GmbH (also located in Munich). They were able to provide a front-end detector module with six 100 m^2 SDD detectors (two monolithic arrays of three elements each) along with

  16. CFAR Edge Detector for Polarimetric SAR Images

    DEFF Research Database (Denmark)

    Schou, Jesper; Skriver, Henning; Nielsen, Allan Aasbjerg;

    2003-01-01

    Finding the edges between different regions in an image is one of the fundamental steps of image analysis, and several edge detectors suitable for the special statistics of synthetic aperture radar (SAR) intensity images have previously been developed. In this paper, a new edge detector...

  17. DELPHI Barrel Ring Imaging Cherenkov Detector

    CERN Multimedia

    DELPHI was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. This is a piece of the Barrel Ring Imaging Cherenkov detector which was used to identify particles in DELPHI.It measured the Cherenkov light emitted when particles travelled faster than the speed of light through the material of the detector. The photo shows the complete Cherenkov detector.

  18. On recall rate of interest point detectors

    DEFF Research Database (Denmark)

    Aanæs, Henrik; Lindbjerg Dahl, Anders; Pedersen, Kim Steenstrup

    2010-01-01

    In this paper we provide a method for evaluating interest point detectors independently of image descriptors. This is possible because we have compiled a unique data set enabling us to determine if common interest points are found. The data contains 60 scenes of a wide range of object types......, and for each scene we have 119 precisely located camera positions obtained from a camera mounted on an industrial robot arm. The scene surfaces have been scanned using structured light, providing precise 3D ground truth. We have investigated a number of the most popular interest point detectors where we...... systematically have varied camera position, light and model parameters. The overall conclusion is that the Harris and Hessian corner detectors perform well followed by MSER, whereas the FAST corner detector, IBR and EBR performs poorly. Furthermore, only the number of interest points change with changing...

  19. High resolution imaging detectors and applications

    CERN Document Server

    Saha, Swapan K

    2015-01-01

    Interferometric observations need snapshots of very high time resolution of the order of (i) frame integration of about 100 Hz or (ii) photon-recording rates of several megahertz (MHz). Detectors play a key role in astronomical observations, and since the explanation of the photoelectric effect by Albert Einstein, the technology has evolved rather fast. The present-day technology has made it possible to develop large-format complementary metal oxide–semiconductor (CMOS) and charge-coupled device (CCD) array mosaics, orthogonal transfer CCDs, electron-multiplication CCDs, electron-avalanche photodiode arrays, and quantum-well infrared (IR) photon detectors. The requirements to develop artifact-free photon shot noise-limited images are higher sensitivity and quantum efficiency, reduced noise that includes dark current, read-out and amplifier noise, smaller point-spread functions, and higher spectral bandwidth. This book aims to address such systems, technologies and design, evaluation and calibration, control...

  20. The pin pixel detector--X-ray imaging

    CERN Document Server

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

    2002-01-01

    The development and testing of a soft X-ray gas pixel detector, which uses connector pins for the anodes is reported. Based on a commercial 100 pin connector block, a prototype detector of aperture 25.4 mm centre dot 25.4 mm can be economically fabricated. The individual pin anodes all show the expected characteristics of small gas detectors capable of counting rates reaching 1 MHz per pin. A 2-dimensional resistive divide readout system has been developed to permit the imaging properties of the detector to be explored in advance of true pixel readout electronics.

  1. Computational imaging with a balanced detector

    Science.gov (United States)

    Soldevila, F.; Clemente, P.; Tajahuerce, E.; Uribe-Patarroyo, N.; Andrés, P.; Lancis, J.

    2016-06-01

    Single-pixel cameras allow to obtain images in a wide range of challenging scenarios, including broad regions of the electromagnetic spectrum and through scattering media. However, there still exist several drawbacks that single-pixel architectures must address, such as acquisition speed and imaging in the presence of ambient light. In this work we introduce balanced detection in combination with simultaneous complementary illumination in a single-pixel camera. This approach enables to acquire information even when the power of the parasite signal is higher than the signal itself. Furthermore, this novel detection scheme increases both the frame rate and the signal-to-noise ratio of the system. By means of a fast digital micromirror device together with a low numerical aperture collecting system, we are able to produce a live-feed video with a resolution of 64 × 64 pixels at 5 Hz. With advanced undersampling techniques, such as compressive sensing, we can acquire information at rates of 25 Hz. By using this strategy, we foresee real-time biological imaging with large area detectors in conditions where array sensors are unable to operate properly, such as infrared imaging and dealing with objects embedded in turbid media.

  2. Computational imaging with a balanced detector.

    Science.gov (United States)

    Soldevila, F; Clemente, P; Tajahuerce, E; Uribe-Patarroyo, N; Andrés, P; Lancis, J

    2016-06-29

    Single-pixel cameras allow to obtain images in a wide range of challenging scenarios, including broad regions of the electromagnetic spectrum and through scattering media. However, there still exist several drawbacks that single-pixel architectures must address, such as acquisition speed and imaging in the presence of ambient light. In this work we introduce balanced detection in combination with simultaneous complementary illumination in a single-pixel camera. This approach enables to acquire information even when the power of the parasite signal is higher than the signal itself. Furthermore, this novel detection scheme increases both the frame rate and the signal-to-noise ratio of the system. By means of a fast digital micromirror device together with a low numerical aperture collecting system, we are able to produce a live-feed video with a resolution of 64 × 64 pixels at 5 Hz. With advanced undersampling techniques, such as compressive sensing, we can acquire information at rates of 25 Hz. By using this strategy, we foresee real-time biological imaging with large area detectors in conditions where array sensors are unable to operate properly, such as infrared imaging and dealing with objects embedded in turbid media.

  3. Imaging gaseous detectors and their applications

    CERN Document Server

    Nappi, Eugenio

    2013-01-01

    Covers the detector and imaging technology and their numerous applications in nuclear and high energy physics, astrophysics, medicine and radiation measurements Foreword from G. Charpak, awarded the Nobel Prize in Physics for this invention.

  4. ENVISION, from particle detectors to medical imaging

    CERN Multimedia

    2013-01-01

    Technologies developed for particle physics detectors are increasingly used in medical imaging tools like Positron Emission Tomography (PET). Produced by: CERN KT/Life Sciences and ENVISION Project Management: Manuela Cirilli 3D animation: Jeroen Huijben, Nymus3d

  5. Noiseless, kilohertz-frame-rate, imaging detector based on micro-channel plates readout with the Medipix2 CMOS pixel chip

    CERN Document Server

    McPhate, J; Tremsin, A; Siegmund, O; Mikulec, Bettina; Clark, Allan G; CERN. Geneva

    2005-01-01

    A new hybrid imaging detector is described that is being developed for the next generation adaptive optics (AO) wavefront sensors. The detector consists of proximity focused microchannel plates (MCPs) read out by pixelated CMOS application specific integrated circuit (ASIC) chips developed at CERN ("Medipix2"). Each Medipix2 pixel has an amplifier, lower and upper charge discriminators, and a 14-bit chounter. The 256x256 array can be read out noiselessly (photon counting) in 286 us. The Medipix2 is buttable on 3 sides to produce 512x(n*256) pixel devices. The readout can be electronically shuttered down to a terporal window of a few microseconds with an accuracy of 10 ns. Good quantum efficiencies can be achieved from the x-ray (open faced with opaque photocathodes) to the optical (sealed tube with multialkali or GaAs photocathode).

  6. Compton imager using room temperature silicon detectors

    Science.gov (United States)

    Kurfess, James D.; Novikova, Elena I.; Phlips, Bernard F.; Wulf, Eric A.

    2007-08-01

    We have been developing a multi-layer Compton Gamma Ray Imager using position-sensitive, intrinsic silicon detectors. Advantages of this approach include room temperature operation, reduced Doppler broadening, and use of conventional silicon fabrication technologies. We have obtained results on the imaging performance of a multi-layer instrument where each layer consists of a 2×2 array of double-sided strip detectors. Each detector is 63 mm×63 mm×2 mm thick and has 64 strips providing a strip pitch of approximately 0.9 mm. The detectors were fabricated by SINTEF ICT (Oslo Norway) from 100 mm diameter wafers. The use of large arrays of silicon detectors appears especially advantageous for applications that require excellent sensitivity, spectral resolution and imaging such as gamma ray astrophysics, detection of special nuclear materials, and medical imaging. The multiple Compton interactions (three or more) in the low-Z silicon enable the energy and direction of the incident gamma ray to be determined without full deposition of the incident gamma-ray energy in the detector. The performance of large volume instruments for various applications are presented, including an instrument under consideration for NASA's Advanced Compton Telescope (ACT) mission and applications to Homeland Security. Technology developments that could further extend the sensitivity and performance of silicon Compton Imagers are presented, including the use of low-energy (few hundred keV) electron tracking within novel silicon detectors and the potential for a wafer-bonding approach to produce thicker, position-sensitive silicon detectors with an associated reduction of required electronics and instrument cost.

  7. High rate resistive plate chamber for LHC detector upgrades

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, Y., E-mail: haddad@llr.in2p3.fr [Laboratoire Leprince-Ringuet (LLR), École Polytechnique, 91120 Palaiseau (France); Laktineh, I.; Grenier, G.; Lumb, N. [IPNL, Villeurbanne 69622 Lyon (France); Cauwenbergh, S. [Ghent University, Ghent (Belgium)

    2013-08-01

    The limitation of the detection rate of standard bakelite resistive plate chambers (RPCs) used as muon detectors in the LHC experiments has prevented the use of such detectors in the high rate regions in both CMS and ATLAS detectors. One alternative to these detectors is RPCs made with low resistivity glass plates (10{sup 10}Ωcm), a beam test at DESY has shown that such detectors can operate at few thousand Hz/cm{sup 2} with high efficiency (>90%)

  8. Neutralino event rates in dark matter detectors

    CERN Document Server

    Arnowitt, Richard Lewis; Pran Nath

    1995-01-01

    ABSTRACT: The expected event rates for {\\tilde Z_{1}} dark matter for a variety of dark matter detectors are studied over the full parameter space with tan \\beta\\leq 20 for supergravity grand unified models. Radiative breaking constraints are implemented and effects of the heavy netural Higgs included as well as loop corrections to the neutral Higgs sector. The parameter space is restricted so that the {\\tilde Z_{1}} relic density obeys 0.10 \\leq\\Omega_{\\tilde Z_{1}}h^2\\leq 0.35, consistent with the COBE data and astronomical determinations of the Hubble constant. It is found that the best detectors sensitive to coherrent {\\tilde Z_{1}} scattering (e.g. Pb) is about 5-10 more sensitive than those based on incoherrent spin dependent scattering (e.g. CaF). In general, the dark matter detectors are most sensistive to the large tan \\beta and small m_o and m_{\\tilde g} sector of the parameter space.

  9. Cerenkov ring imaging detector development: Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.; Ratcliff, B.

    1988-10-01

    We present recent progress on the construction and testing of the first drift boxes and single electron detectors as they come from the production line. These detectors will be used for particle identification using the Ring Imaging technique in the SLD experiment at SLAC. Various experimental results are presented, including single electron pulse height measurements as a function of gas gain, detector gating capability, uniformity of response across the wire plane, charge division performance of a single electron signal, average pulse shape and its comparison with predicted shape, and cross-talk. 14 refs., 11 figs.

  10. The BRAHMS ring imaging Cherenkov detector

    Science.gov (United States)

    Debbe, R.; Jørgensen, C. E.; Olness, J.; Yin, Z.

    2007-01-01

    A Ring Imaging Cherenkov detector built for the BRAHMS experiment at the Brookhaven RHIC is described. This detector has a high index of refraction gas radiator. Cherenkov light is focused on a photo-multiplier based photon detector with a large spherical mirror. The combination of momentum and ring radius measurement provides particle identification from 2.5 to 35 GeV/ c for pions and kaons and well above 40 GeV/ c for protons during runs that had the radiator index of refraction set at n-1=1700×10-6.

  11. Musculoskeletal imaging with a prototype photon-counting detector

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, M.; Uffmann, M.; Kainberger, F. [Medical University of Vienna, Department of Radiology, Vienna (Austria); Homolka, P. [Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna (Austria); Chmeissani, M. [Institute for High Energy Physics, Medigal Imaging, Barcelona (Spain); Pretterklieber, M. [Medical University of Vienna, Center for Anatomy and Cell Biology, Vienna (Austria)

    2012-01-15

    To test a digital imaging X-ray device based on the direct capture of X-ray photons with pixel detectors, which are coupled with photon-counting readout electronics. The chip consists of a matrix of 256 x 256 pixels with a pixel pitch of 55 {mu}m. A monolithic image of 11.2 cm x 7 cm was obtained by the consecutive displacement approach. Images of embalmed anatomical specimens of eight human hands were obtained at four different dose levels (skin dose 2.4, 6, 12, 25 {mu}Gy) with the new detector, as well as with a flat-panel detector. The overall rating scores for the evaluated anatomical regions ranged from 5.23 at the lowest dose level, 6.32 at approximately 6 {mu}Gy, 6.70 at 12 {mu}Gy, to 6.99 at the highest dose level with the photon-counting system. The corresponding rating scores for the flat-panel detector were 3.84, 5.39, 6.64, and 7.34. When images obtained at the same dose were compared, the new system outperformed the conventional DR system at the two lowest dose levels. At the higher dose levels, there were no significant differences between the two systems. The photon-counting detector has great potential to obtain musculoskeletal images of excellent quality at very low dose levels. (orig.)

  12. Neutron beam imaging with GEM detectors

    Science.gov (United States)

    Albani, G.; Croci, G.; Cazzaniga, C.; Cavenago, M.; Claps, G.; Muraro, A.; Murtas, F.; Pasqualotto, R.; Perelli Cippo, E.; Rebai, M.; Tardocchi, M.; Gorini, G.

    2015-04-01

    Neutron GEM-based detectors represent a new frontier of devices in neutron physics applications where a very high neutron flux must be measured such as future fusion experiments (e.g. ITER Neutral beam Injector) and spallation sources (e.g. the European Spallation source). This kind of detectors can be properly adapted to be used both as beam monitors but also as neutron diffraction detectors that could represent a valid alternative for the 3He detectors replacement. Fast neutron GEM detectors (nGEM) feature a cathode composed by one layer of polyethylene and one of aluminium (neutron scattering on hydrogen generates protons that are detected in the gas) while thermal neutron GEM detectors (bGEM) are equipped with a borated aluminium cathode (charged particles are generated through the 10B(n,α)7Li reaction). GEM detectors can be realized in large area (1 m2) and their readout can be pixelated. Three different prototypes of nGEM and one prototype of bGEM detectors of different areas and equipped with different types of readout have been built and tested. All the detectors have been used to measure the fast and thermal neutron 2D beam image at the ISIS-VESUVIO beamline. The different kinds of readout patterns (different areas of the pixels) have been compared in similar conditions. All the detectors measured a width of the beam profile consitent with the expected one. The imaging property of each detector was then tested by inserting samples of different material and shape in the beam. All the samples were correctly reconstructed and the definition of the reconstruction depends on the type of readout anode. The fast neutron beam profile reconstruction was then compared to the one obtained by diamond detectors positioned on the same beamline while the thermal neutron one was compared to the imaged obtained by cadmium-coupled x-rays films. Also efficiency and the gamma background rejection have been determined. These prototypes represent the first step towards the

  13. CZT imaging detectors for ProtoEXIST

    CERN Document Server

    Hong, J; Chammas, N; Copete, A; Baker, R G; Barthelmy, S D; Gehrels, N; Cook, W R; Burnham, J A; Harrison, F A; Collins, J; Craig, W W

    2006-01-01

    We describe the detector development for a balloon-borne wide-field hard X-ray (20 - 600 keV) telescope, ProtoEXIST. ProtoEXIST is a pathfinder for both technology and science of the proposed implementation of the Black Hole Finder Probe, Energetic X-ray Imaging Survey telescope (EXIST). The principal technology challenge is the development of large area, close-tiled modules of imaging CZT detectors (1000 cm2 for ProtoEXIST1). We review the updates of the detector design and package concept for ProtoEXIST1 and report the current development status of the CZT detectors, using calibration results of our basic detector unit - 2 x 2 x 0.5 cm CZT crystals with 2.5 mm pixels (8 x 8 array). The current prototype (Rev1) of our detector crystal unit (DCU) shows ~4.5 keV electronics noise (FWHM), and the radiation measurements show the energy resolution (FWHM) of the units is 4.7 keV (7.9%) at 59.5 keV, 5.6 keV (4.6%) at 122 keV, and 7.6 keV (2.1%) at 356 keV. The new (Rev2) DCU with revised design is expected to impro...

  14. 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.

  15. Detectors for the future of X-ray imaging.

    Science.gov (United States)

    Aslund, M; Fredenberg, E; Telman, M; Danielsson, M

    2010-01-01

    In recent decades, developments in detectors for X-ray imaging have improved dose efficiency. This has been accomplished with for example, structured scintillators such as columnar CsI, or with direct detectors where the X rays are converted to electric charge carriers in a semiconductor. Scattered radiation remains a major noise source, and fairly inefficient anti-scatter grids are still a gold standard. Hence, any future development should include improved scatter rejection. In recent years, photon-counting detectors have generated significant interest by several companies as well as academic research groups. This method eliminates electronic noise, which is an advantage in low-dose applications. Moreover, energy-sensitive photon-counting detectors allow for further improvements by optimising the signal-to-quantum-noise ratio, anatomical background subtraction or quantitative analysis of object constituents. This paper reviews state-of-the-art photon-counting detectors, scatter control and their application in diagnostic X-ray medical imaging. In particular, spectral imaging with photon-counting detectors, pitfalls such as charge sharing and high rates and various proposals for mitigation are discussed.

  16. Microchannel Plate Imaging Detectors for the Ultraviolet

    Science.gov (United States)

    Siegmund, O. H. W.; Gummin, M. A.; Stock, J.; Marsh, D.

    1992-01-01

    There has been significant progress over the last few years in the development of technologies for microchannel plate imaging detectors in the Ultraviolet (UV). Areas where significant developments have occurred include enhancements of quantum detection efficiency through improved photocathodes, advances in microchannel plate performance characteristics, and development of high performance image readout techniques. The current developments in these areas are summarized, with their applications in astrophysical instrumentation.

  17. 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.

  18. 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.

  19. Multispectral imaging using a single bucket detector

    CERN Document Server

    Bian, Liheng; Situ, Guohai; Li, Ziwei; Chen, Feng; Dai, Qionghai

    2015-01-01

    Current multispectral imagers suffer from low photon efficiency and limited spectrum range. These limitations are partially due to the technological limitations from array sensors (CCD or CMOS), and also caused by separative measurement of the entries/slices of a spatial-spectral data cube. Besides, they are mostly expensive and bulky. To address above issues, this paper proposes to image the 3D multispectral data with a single bucket detector in a multiplexing way. Under the single pixel imaging scheme, we project spatial-spectral modulated illumination onto the target scene to encode the scene's 3D information into a 1D measurement sequence. Conventional spatial modulation is used to resolve the scene's spatial information. To avoid increasing requisite acquisition time for 2D to 3D extension of the latent data, we conduct spectral modulation in a frequency-division multiplexing manner in the speed gap between slow spatial light modulation and fast detector response. Then the sequential reconstruction falls...

  20. 15th International Workshop on Radiation Imaging Detectors

    CERN Document Server

    2013-01-01

    The International Workshops on Radiation Imaging Detectors are held yearly and provide an international forum for discussing current research and developments in the area of position sensitive detectors for radiation imaging, including semiconductor detectors, gas- and scintillator-based detectors. Topics include processing and characterization of detector materials, hybridization and interconnect technologies, design of counting or integrating electronics, readout and data acquisition systems, and applications in various scientific and industrial fields.

  1. Cerenkov ring imaging detector development at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Williams, S.H.

    1984-06-01

    The imaging of Cerenkov light on to photosensitive detectors promises to be a powerful technique for identifying particles in colliding beam spectrometers. Toward this end two and three dimensional imaging photon detectors are being developed at SLAC. The present techniques involve photon conversion using easily ionized exotic chemicals like tetrakisdimethyl-amino-ethylene (TMAE) in a drift and amplifying gas mixture of methane and isobutane. Single photoelectrons from Cerenkov light are currently being drifted 20 cm and a new device under study will be used to study drifting up to 80 cm along a magnetic field. A short description of a large device currently being designed for the SLD spectrometer at the Stanford Linear Collider will be given.

  2. Rate equation modelling and investigation of quantum cascade detector characteristics

    Science.gov (United States)

    Saha, Sumit; Kumar, Jitendra

    2016-10-01

    A simple precise transport model has been proposed using rate equation approach for the characterization of a quantum cascade detector. The resonant tunneling transport is incorporated in the rate equation model through a resonant tunneling current density term. All the major scattering processes are included in the rate equation model. The effect of temperature on the quantum cascade detector characteristics has been examined considering the temperature dependent band parameters and the carrier scattering processes. Incorporation of the resonant tunneling process in the rate equation model improves the detector performance appreciably and reproduces the detector characteristics within experimental accuracy.

  3. Multispectral imaging using a single bucket detector.

    Science.gov (United States)

    Bian, Liheng; Suo, Jinli; Situ, Guohai; Li, Ziwei; Fan, Jingtao; Chen, Feng; Dai, Qionghai

    2016-04-22

    Existing multispectral imagers mostly use available array sensors to separately measure 2D data slices in a 3D spatial-spectral data cube. Thus they suffer from low photon efficiency, limited spectrum range and high cost. To address these issues, we propose to conduct multispectral imaging using a single bucket detector, to take full advantage of its high sensitivity, wide spectrum range, low cost, small size and light weight. Technically, utilizing the detector's fast response, a scene's 3D spatial-spectral information is multiplexed into a dense 1D measurement sequence and then demultiplexed computationally under the single pixel imaging scheme. A proof-of-concept setup is built to capture multispectral data of 64 pixels × 64 pixels × 10 wavelength bands ranging from 450 nm to 650 nm, with the acquisition time being 1 minute. The imaging scheme holds great potentials for various low light and airborne applications, and can be easily manufactured as production-volume portable multispectral imagers.

  4. First observation of Cherenkov ring images using hybrid photon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, E.; Wilkinson, G. [European Organization for Nuclear Research, Geneva (Switzerland). Div. Particle Physics Experiments; Barber, G.; Duane, A.; John, M.; Miller, D.G.; Websdale, D. [Imperial College of Science Technology and Medicine, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Bibby, J.H.; Giles, R.; Harnew, N.; Smale, N. [University of Oxford, Department of Nuclear Physics, Keble Road, Oxford OX1 3RH (United Kingdom); Brook, N.H.; Halley, A.W.; O`Shea, V. [University of Glasgow, Department of Physics, Glasgow G12 8QQ (United Kingdom); French, M. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Gibson, V.; Wotton, S.A. [University of Cambridge, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE (United Kingdom); Schomaker, R. [Delft Electronic Products BV, 9300 AB Roden (Netherlands)

    1998-07-11

    A ring-imaging Cherenkov detector, equipped with hybrid photon detectors, has been operated in a charged-particle beam. Focussed ring images from various particle types were detected using silica aerogel, air and C{sub 4}F{sub 10} gas radiators. The detector, a prototype for the CERN LHC-B experiment, is described and first observations are reported. (orig.)

  5. Advanced digital detectors for neutron imaging.

    Energy Technology Data Exchange (ETDEWEB)

    Doty, F. Patrick

    2003-12-01

    Neutron interrogation provides unique information valuable for Nonproliferation & Materials Control and other important applications including medicine, airport security, protein crystallography, and corrosion detection. Neutrons probe deep inside massive objects to detect small defects and chemical composition, even through high atomic number materials such as lead. However, current detectors are bulky gas-filled tubes or scintillator/PM tubes, which severely limit many applications. Therefore this project was undertaken to develop new semiconductor radiation detection materials to develop the first direct digital imaging detectors for neutrons. The approach relied on new discovery and characterization of new solid-state sensor materials which convert neutrons directly to electronic signals via reactions BlO(n,a)Li7 and Li6(n,a)T.

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

    Science.gov (United States)

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

    2011-07-01

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

  7. Neutron imagingDetector options in progress

    Science.gov (United States)

    Lehmann, E. H.; Tremsin, A.; Grünzweig, C.; Johnson, I.; Boillat, P.; Josic, L.

    2011-01-01

    Neutron imaging is a non-invasive method for material research on the macroscopic level. It is carried out at laboratories equipped with powerful neutron sources, suitable neutron beam lines and neutron detection systems. Decades ago neutron radiography began capturing images with film techniques. These techniques yielded excellent spatial resolution even over large fields of view. In the recent years, improvements in the detection techniques and their digitization have been the main forces driving successes in neutron imaging. Several detector options have been developed, implemented and used in practical applications in order to achieve digital information from the neutron transmission process which is needed for a quantitative evaluation of image data by sophisticated methods like neutron tomography, phase contrast imaging, neutron interferometry and time dependent studies. The most common approach in digital neutron imaging is a conversion of the neutron field information into visible light by a scintillation process, where a neutron converter is needed because neutrons do not excite directly due to their neutral charge. Low level light signals can be observed either with sensitive camera systems or by using amorphous silicon based semiconductor plate devices. However, these now established detection techniques are still limited in respect to spatial and time resolution. The best possible spatial resolution which can be achieved today is available by a system built at PSI with about 10 μm pixel size. Recently, it was upgraded with a tilted option for an increased resolution by a factor of 4 in one direction. Scintillator based techniques are limited by the dissipation of the secondary particles. This limitation has motivated the search for new detector options. One approach is a pixilated system where the readout per incoming neutron can be used to calculate precisely the position of its impact. Such devices are realized as the TIMEPIX system already. The

  8. Microtomography with sandwich detectors for small-animal bone imaging

    Science.gov (United States)

    Kim, S. H.; Kim, D. W.; Kim, D.; Youn, H.; Cho, S.; Kim, H. K.

    2016-10-01

    An x-ray radiographic system consisting of two detectors in tandem, or a sandwich detector, can produce dual-energy image from a single-shot exposure. Subtraction of two images obtained from the two detectors can produce a sharper image through an unsharp masking effect if the two images are formed at different spatial resolutions. This is indeed possible by incorporating different thicknesses of x-ray conversion layers in the detectors. In this study, we have developed a microtomography system with a sandwich detector in pursuit of high-resolution bone-enhanced small-animal imaging. The results show that the bone-enhanced images reconstructed from the dual-energy projection data provide higher visibility of bone details than the conventionally reconstructed images. The microtomography with the single-shot dual-energy sandwich detector will be useful for the high-resolution bone-enhanced small-animal imaging.

  9. On Recall Rate of Interest Point Detectors

    DEFF Research Database (Denmark)

    Aanæs, Henrik; Lindbjerg Dahl, Anders; Pedersen, Kim Steenstrup

    2010-01-01

    , and for each scene we have 119 precisely located camera positions obtained from a camera mounted on an industrial robot arm. The scene surfaces have been scanned using structured light, providing precise 3D ground truth. We have investigated a number of the most popular interest point detectors where we...

  10. The Ring Imaging Cherenkov Detectors for LHCb

    CERN Document Server

    Papanestis, Antonis

    2005-01-01

    The success of the LHCb experiment depends heavily on particle identification over the momentum 2-100 GeV/c. To meet this challenge, LHCb uses a Ring Imaging Cherenkov (RICH) system composed of two detectors with three radiators. RICH1 has both aerogel and gas (C$_4$F$_{10}$) radiators, while RICH2 has only a gas (CF$_4$) radiator. The design of RICH1 is almost complete, whereas RICH2 has been constructed and installed (Nov 2005). Novel Hybrid Photon Detectors (HPDs) have been developed in collaboration with industry to detect the Cherenkov photons. A silicon pixel detector bump-bonded to a readout chip is encapsulated in a vacuum tube. A bi-alkali photocathode is deposited on the inside of the quartz entrance window to convert photons in the range 200-600 nm. The pixel chip is manufactured in 0.25 $\\mu$m deep-submicron radiation-tolerant technology and consists of 1024 logical pixels, each pixel having an area of 0.5 mm x 05. Mm. Photo-electrons are accelerated by a 20kV potential, resulting in a signal of ...

  11. Development of ring imaging Cherenkov detectors for the LHCb experiment

    CERN Document Server

    John, M J J

    2001-01-01

    This thesis reports on work done as part of the development of the Ring Imaging Cherenkov (RICH) detectors of the LHCb experiment. The context of this work is set out in Chapter 1, which includes an overview of the physics of CP violation, followed by a discussion of other experiments that study B physics. LHCb itself is then described, with particular emphasis on its RICH detectors, and the photon detectors to be used therein. The work done by the author to ensure an adequate shielding of the photon detectors in the two RICH detectors from the magnetic fields produced by the LHCb dipole is then presented. A candidate photodetector for the RICH is the Pixel HPD. The author's contribution to the upgrade of the HPD test system to operate at the LHC bunch-crossing rate of 40MHz is the subject of the following section. This system was used to investigate and optimise a method of minimising the threshold distribution of the Pixel HPD's encapsulated readout chip. The final chapter of the thesis concerns the aerogel...

  12. Imaging in (high pressure) Micromegas TPC detectors

    Science.gov (United States)

    Luzón, G.; Cebrián, S.; Castel, J.; Dafni, Th.; Galán, J.; Garza, J. G.; Irastorza, I. G.; Iguaz, F. J.; Mirallas, H.; Ruíz-Choliz, E.

    2016-11-01

    The T-REX project of the group of the University of Zaragoza includes a number of R&D and prototyping activities to explore the applicability of gaseous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) in rare event searches where the pattern recognition of the signal is crucial for background discrimination. In the CAST experiment (CERN Axion Solar Telescope) a background level as low as 0.8 × 10-6 counts keV-1 cm-2 s-1 was achieved. Prototyping and simulations promise a 105 better signal-to-noise ratio than CAST for the future IAXO (International Axion Observatory) using x-ray telescopes. A new strategy is also explored in the search of WIMPS based on high gas pressure: the TREX-DM experiment, a low energy threshold detector. In both cases, axion and WIMP searches, the image of the expected signal is quite simple: a one cluster deposition coming from the magnet bore in the case of axions and, if possible, with a tadpole form in the case of WIMPs. It is the case of double beta decay (DBD) where imaging and pattern recognition play a major role. Results obtained in Xe + trimethylamine (TMA) mixture point to a reduction in electron diffusion which improves the quality of the topological pattern, with a positive impact on the discrimination capability, as shown in TREX-ββ prototype. Microbulk Micromegas are able to image the DBD ionization signature with high quality while, at the same time, measuring its energy deposition with a resolution of at least a ~ 3% FWHM at the transition energy Qββ and even better (up to ~ 1% FWHM) as extrapolated from low energy events. That makes Micromegas-based HPXe TPC a very competitive technique for the next generation DBD experiments (as PANDAX-III). Here, it will be shown the last results of the TREX project detectors and software concerning Axions, Dark matter and double beta decay.

  13. 2-D straw detectors with high rate capability

    CERN Document Server

    Kuchinskiy, N A; Duginov, V N; Zyazyulya, F E; Korenchenko, A S; Kolesnikov, A O; Kravchuk, N P; Movchan, S A; Rudenko, A I; Smirnov, V S; Khomutov, N V; Chekhovsky, V A; Lobko, A S; Misevich, O V

    2015-01-01

    Precise measurement of straw axial coordinate (along the anode wire) with accuracy compatible with straw radial coordinate determination by drift time measurement and increase of straw detector rate capability by using straw cathode readout instead of anode readout are presented.

  14. 18th International Workshop on Radiation Imaging Detectors

    CERN Document Server

    2016-01-01

    The International Workshops on Radiation Imaging Detectors are held yearly and provide an international forum for discussing current research and developments in the area of position sensitive detectors for radiation imaging, including semiconductor detectors, gas and scintillator-based detectors. Topics include processing and characterization of detector materials, hybridization and interconnect technologies, design of counting or integrating electronics, readout and data acquisition systems, and applications in various scientific and industrial fields. The workshop will have plenary sessions with invited and contributed papers presented orally and in poster sessions. The invited talks will be chosen to review recent advances in different areas covered in the workshop.

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

    Science.gov (United States)

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

    2012-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Szczygiel, R., E-mail: robert.szczygiel@agh.edu.pl [AGH University of Science and Technology, Department of Measurement and Instrumentation, Al. Mickiewicza 30, 30-059 Cracow (Poland); Grybos, P.; Maj, P. [AGH University of Science and Technology, Department of Measurement and Instrumentation, Al. Mickiewicza 30, 30-059 Cracow (Poland)

    2012-07-11

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

  17. Software Development for Ring Imaging Detector

    Science.gov (United States)

    Torisky, Benjamin

    2016-03-01

    Jefferson Lab (Jlab) is performing a large-scale upgrade to their Continuous Electron Beam Accelerator Facility (CEBAF) up to 12GeV beam. The Large Acceptance Spectrometer (CLAS12) in Hall B is being upgraded and a new Ring Imaging Cherenkov (RICH) detector is being developed to provide better kaon - pion separation throughout the 3 to 12 GeV range. With this addition, when the electron beam hits the target, the resulting pions, kaons, and other particles will pass through a wall of translucent aerogel tiles and create Cherenkov radiation. This light can then be accurately detected by a large array of Multi-Anode PhotoMultiplier Tubes (MA-PMT). I am presenting an update on my work on the implementation of Java based reconstruction programs for the RICH in the CLAS12 main analysis package.

  18. Electron imaging with Medipix2 hybrid pixel detector

    CERN Document Server

    McMullan, G; Chen, S; Henderson, R; Llopart, X; Summerfield, C; Tlustos, L; Faruqi, A R

    2007-01-01

    The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 μm×55 μm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 μm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach 85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach 35% of that expected for a perfect detector (4/π2). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/π). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected v...

  19. Bunch mode specific rate corrections for PILATUS3 detectors

    Energy Technology Data Exchange (ETDEWEB)

    Trueb, P., E-mail: peter.trueb@dectris.com [DECTRIS Ltd, 5400 Baden (Switzerland); Dejoie, C. [ETH Zurich, 8093 Zurich (Switzerland); Kobas, M. [DECTRIS Ltd, 5400 Baden (Switzerland); Pattison, P. [EPF Lausanne, 1015 Lausanne (Switzerland); Peake, D. J. [School of Physics, The University of Melbourne, Victoria 3010 (Australia); Radicci, V. [DECTRIS Ltd, 5400 Baden (Switzerland); Sobott, B. A. [School of Physics, The University of Melbourne, Victoria 3010 (Australia); Walko, D. A. [Argonne National Laboratory, Argonne, IL 60439 (United States); Broennimann, C. [DECTRIS Ltd, 5400 Baden (Switzerland)

    2015-04-09

    The count rate behaviour of PILATUS3 detectors has been characterized for seven bunch modes at four different synchrotrons. The instant retrigger technology of the PILATUS3 application-specific integrated circuit is found to reduce the dependency of the required rate correction on the synchrotron bunch mode. The improvement of using bunch mode specific rate corrections based on a Monte Carlo simulation is quantified. PILATUS X-ray detectors are in operation at many synchrotron beamlines around the world. This article reports on the characterization of the new PILATUS3 detector generation at high count rates. As for all counting detectors, the measured intensities have to be corrected for the dead-time of the counting mechanism at high photon fluxes. The large number of different bunch modes at these synchrotrons as well as the wide range of detector settings presents a challenge for providing accurate corrections. To avoid the intricate measurement of the count rate behaviour for every bunch mode, a Monte Carlo simulation of the counting mechanism has been implemented, which is able to predict the corrections for arbitrary bunch modes and a wide range of detector settings. This article compares the simulated results with experimental data acquired at different synchrotrons. It is found that the usage of bunch mode specific corrections based on this simulation improves the accuracy of the measured intensities by up to 40% for high photon rates and highly structured bunch modes. For less structured bunch modes, the instant retrigger technology of PILATUS3 detectors substantially reduces the dependency of the rate correction on the bunch mode. The acquired data also demonstrate that the instant retrigger technology allows for data acquisition up to 15 million photons per second per pixel.

  20. 2D Detectors for Particle Physics and for Imaging Applications

    CERN Document Server

    Krüger, H

    2005-01-01

    The demands on detectors for particle detection as well as for medical and astronomical X-ray imaging are continuously pushing the development of novel pixel detectors. The state of the art in pixel detector technology to date are hybrid pixel detectors in which sensor and read-out integrated circuits are processed on different substrates and connected via high density interconnect structures. While these detectors are technologically mastered such that large scale particle detectors can be and are being built, the demands for improved performance for the next generation particle detectors ask for the development of monolithic or semi-monolithic approaches. Given the fact that the demands for medical imaging are different in some key aspects, developments for these applications, which started as particle physics spin-off, are becomming rather independent. New approaches are leading to novel signal processing concepts and interconnect technologies to satisfy the need for very high dynamic range and large area ...

  1. Turnover Rate Simulation Using GEM Detector on Neutron Radiography

    Institute of Scientific and Technical Information of China (English)

    SHAN; Chao; LI; Xiao-mei; HU; Shou-yang; ZHOU; Jing; JIAN; Si-yu; BAI; Xin-zhan; YE; Li; ZHOU; Shu-hua

    2012-01-01

    <正>With the advantages of high counting rate, high resolution ratio and high compatibility, GEM (Gas Electron Multiplier) detector has becoming the hot topic in the field of gas detector. Using GEM on neutron radiography, we need a suitable neutron converter. By the action on the converter and ingoing neutron, the outgoing particles could be an alpha or proton, which are charged particles. The charged

  2. Combined scintillation detector for gamma dose rate measurement

    Energy Technology Data Exchange (ETDEWEB)

    Viererbl, L.; Novakova, O.; Jursova, L. (Tesla, Premysleni (Czechoslovakia). Vyzkumny Ustav Pristroju Jaderne Techniky)

    1990-01-01

    The specifications are described of a newly developed scintillation detector, essentially consisting of a plastic scintillator completed with inorganic scintillators ZnS(Ag) and NaI(Tl). The gamma dose rate is derived from the photomultiplier anode current. The composition and sizes of the scintillators and the capsule are selected so as to minimise the energy dependence errors and directional dependence errors of the detector response over a wide range of energies and/or angles. (author).

  3. High rate multiplicity detector for relativistic heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Beavis, D. [Brookhaven National Lab., Upton, NY (United States); Bennett, M.J. [Yale University, A.W. Wright Nuclear Structure Laboratory, New Haven, CT 06511 (United States); Carroll, J.B. [University of California at Los Angeles, Los Angeles, CA (United States); Chiba, J. [KEK National High Energy Physics, Tsukuba (Japan); Chikanian, A. [Yale University, A.W. Wright Nuclear Structure Laboratory, New Haven, CT 06511 (United States); Crawford, H.J. [University of California Space Sciences Laboratory, Berkeley, CA (United States); Cronqvist, M. [University of California Space Sciences Laboratory, Berkeley, CA (United States); Dardenne, Y. [University of California Space Sciences Laboratory, Berkeley, CA (United States); Debbe, R. [Brookhaven National Lab., Upton, NY (United States); Doke, T. [Waseda University, Science and Engineering Research Institute, Waseda (Japan); Engelage, J. [University of California Space Sciences Laboratory, Berkeley, CA (United States); Flores, I. [University of California Space Sciences Laboratory, Berkeley, CA (United States); Greiner, L. [University of California Space Sciences Laboratory, Berkeley, CA (United States); Hayano, R.S. [University of Tokyo, Tokyo (Japan); Hallman, T.J. [University of California at Los Angeles, Los Angeles, CA (United States); Heckman, H.H. [Lawrence Berkeley Lab., CA (United States); Kashiwagi, T. [Waseda University, Science and Engineering Research Institute, Waseda (Japan); Kikuchi, J. [Waseda University, Science and Engineering Research Institute, Waseda (Japan); Kumar, B.S. [Yale University, A.W. Wright Nuclear Structure Laboratory, New Haven, CT 06511 (United States); Kuo, C. [University of California Space Sciences Laboratory, Berkeley, CA (United States); Lindstrom, P.J. [Lawrence Berkeley Lab., CA (United States); Mitchell, J.W. [Universities Space Research Association/Goddard Space Flight Center, Greenbelt, MD (United States); Nagamiya, S.; E878 Collaboration

    1995-04-21

    We have constructed and operated a detector to measure the multiplicity of secondary particles produced in nucleus-nucleus collisions in the E878 experiment at the Brookhaven National Laboratory AGS facility. We describe the operation and performance of the detector in a high rate Au beam environment, and interpret the multiplicity data in terms of the impact parameters of the nucleus-nucleus collisions. ((orig.)).

  4. Microtomography with a sandwich detector for mouse bone imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Ho; Kim, Junwoo; Kim, Ho Kyung [Pusan National University, Busan (Korea, Republic of); Youn, Hanbean; Jeon, Hosang [Pusan National University Yangsan Hospital, Yangsan (Korea, Republic of)

    2015-10-15

    Single-shot dual-energy imaging, using sandwich detector, the rear detector usually uses a thicker x-ray converter to enhance quantum efficiency with the higher-energy spectrum, hence providing a blurrier image than the front detector. The weighted logarithmic subtraction of the two images therefore results in a form of unsharp masking that enhances edges in the resultant image. Inspired by this observation, we have developed a micro computed tomography (micro-CT) system with the sandwich detector for high-resolution bone imaging of small animals. The sandwich detector consists of two flat-panel detectors by stacking one upon the other. Although the x-ray beam continuously irradiates, the step-rotation of an object and stay-readout of projection data were considered for the scanning and data gathering. It will be necessary that more elaborate experiments with the mouse and/or other quantitative phantoms. And quantification of the image quality of bone-enhanced images in comparisons with the conventional images will be performed. The image analysis of differences between bone-enhanced images obtained from the projection- and image-based approaches can be performed.

  5. Spatial resolution of a μPIC-based neutron imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Parker, J.D., E-mail: jparker@cr.scphys.kyoto-u.ac.jp [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Harada, M. [Materials and Life Science Facility Division, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Hattori, K.; Iwaki, S.; Kabuki, S.; Kishimoto, Y.; Kubo, H.; Kurosawa, S.; Matsuoka, Y.; Miuchi, K.; Mizumoto, T.; Nishimura, H. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Oku, T. [Materials and Life Science Facility Division, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Sawano, T. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Shinohara, T.; Suzuki, J. [Materials and Life Science Facility Division, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Takada, A.; Tanimori, T.; Ueno, K. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan)

    2013-10-21

    We present a detailed study of the spatial resolution of our time-resolved neutron imaging detector utilizing a new neutron position reconstruction method that improves both spatial resolution and event reconstruction efficiency. Our prototype detector system, employing a micro-pattern gaseous detector known as the micro-pixel chamber (μPIC) coupled with a field-programmable-gate-array-based data acquisition system, combines 100μm-level spatial and sub-μs time resolutions with excellent gamma rejection and high data rates, making it well suited for applications in neutron radiography at high-intensity, pulsed neutron sources. From data taken at the Materials and Life Science Experimental Facility within the Japan Proton Accelerator Research Complex (J-PARC), the spatial resolution was found to be approximately Gaussian with a sigma of 103.48±0.77μm (after correcting for beam divergence). This is a significant improvement over that achievable with our previous reconstruction method (334±13μm), and compares well with conventional neutron imaging detectors and with other high-rate detectors currently under development. Further, a detector simulation indicates that a spatial resolution of less than 60μm may be possible with optimization of the gas characteristics and μPIC structure. We also present an example of imaging combined with neutron resonance absorption spectroscopy. -- Highlights: • Neutron imaging detector with micro-pattern gaseous detector and {sup 3}He was developed. • Detector combines imaging with energy by time-of-flight and high-rate capability. • Detector features 18% efficiency, 0.6μs time resolution, and γ sensitivity <10{sup −12}. • New analysis method with template fit achieves spatial resolution of nearly 100μm. • Simulation study indicates improvement to ∼60μm after optimization.

  6. Using quantum filters as edge detectors in infrared images

    Science.gov (United States)

    Bolaños Marín, Daniela

    2014-06-01

    Some new filters inspired in quantum models are used as edge detectors in infrared images. In this case, Bessel, Hermite and Morse filters will be applied to detect edges and fibrillar structures in infrared images. The edge detectors will be built by the Laplacian of the mentioned quantum filters. Furthermore, using curvature operators, curvature detectors and amplifiers of contrast will be constructed to analyze infrared images. The quantum filter prototyping will be done using computer algebra software, specifically Maple and its package, ImageTools. The quantum filters will be applied to infrared images using the technique of convolutions and blurred derivatives. It is expected that designed quantum filters will be useful for analysis and processing of infrared images. As future investigations, we propose to design plugins with the quantum filters that can be incorporated into the program ImageJ, which will facilitate the use of the quantum filters for the infrared image processing.

  7. A single CdZnTe detector for simultaneous CT/SPECT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Barber, W.C. E-mail: bill@barber.uscf.edu; Iwata, Koji; Hasegawa, B.H.; Bennett, P.R.; Cirignano, L.J.; Shah, K.S

    2003-06-01

    Clinical CT/SPECT systems acquire CT and SPECT data sequentially using different detectors in close proximity to minimise patient movement and interscan delay. We have developed a prototype simultaneous CT/SPECT imager, using a single CdZnTe detector, with the goal of improving image coregistration and decreasing scan time. A 16-pixel CdZnTe detector was operated in pulse-counting mode with 50 ns shaping time. Energy discrimination is used to separate the CT and SPECT data. Simultaneous SPECT and CT images were obtained for a phantom with the X-ray flux limited to reduce pulse pile-up in the radionuclide energy window. At 140 keV, the efficiency and energy resolution are 70% and 10%, respectively, and were constant for fluence rates up to 10{sup 3} cps per detector element for 140 keV gamma rays, but degrade rapidly at higher fluence rates. In pulse-counting mode, the maximum count rate of 10{sup 3} cps per element from the CdZnTe detector is sufficient for SPECT imaging, but is considerably lower than the fluence rates encountered in CT. The smallest lesion visually detectable in SPECT is 9 mm and the CT spatial resolution is smaller than 4.5 mm. Image registration is intrinsic because the data can be acquired simultaneously with a single detector with the same reconstruction geometry.

  8. Imaging detectors and electronics - A view of the future

    Energy Technology Data Exchange (ETDEWEB)

    Spieler, Helmuth

    2004-06-16

    Imaging sensors and readout electronics have made tremendous strides in the past two decades. The application of modern semiconductor fabrication techniques and the introduction of customized monolithic integrated circuits have made large scale imaging systems routine in high energy physics. This technology is now finding its way into other areas, such as space missions, synchrotron light sources, and medical imaging. I review current developments and discuss the promise and limits of new technologies. Several detector systems are described as examples of future trends. The discussion emphasizes semiconductor detector systems, but I also include recent developments for large-scale superconducting detector arrays.

  9. Study of X-ray Imaging of GEM Detector

    Institute of Scientific and Technical Information of China (English)

    LI; Xiao-mei; HU; Shou-yang; JIAN; Si-yu; ZHOU; Jing; LI; Xing-long; LIANG; Hao; ZHOU; Shu-hua

    2015-01-01

    A 10cm×10cm GEM detector made by 3GEM foils was used in the X-ray imaging experiment.2-D strips readout mode was used and each dimension has 256channels with a pitch of 400micrometer.APV25front-end readout chip was introduced in the detector,and the backplane connectors were improved in order to adapt the electronics with GEM detector.Since each

  10. The Use of Radiation Detectors in Medicine: Radiation Detectors for Functional Imaging (2/3)

    CERN Document Server

    CERN. Geneva

    2009-01-01

    The development of radiation detectors in the field of nuclear and particle physics has had a terrific impact in medical imaging since this latter discipline took off in late ’70 with the invention of the CT scanners. The massive use in High Energy Physics of position sensitive gas detectors, of high Z and high density scintillators coupled to Photomultiplier (PMT) and Position Sensitive Photomultipliers (PSPMT), and of solid state detectors has triggered during the last 30 years a series of novel applications in Medical Imaging with ionizing radiation. The accelerated scientific progression in genetics and molecular biology has finally generated what it is now called Molecular Imaging. This field of research presents additional challenges not only in the technology of radiation detector, but more and more in the ASIC electronics, fast digital readout and parallel software. In this series of three lectures I will try to present how high energy physics and medical imaging development have both benefited by t...

  11. The Use of Radiation Detectors in Medicine: Radiation Detectors for Morphological Imaging (1/3)

    CERN Document Server

    CERN. Geneva

    2009-01-01

    The development of radiation detectors in the field of nuclear and particle physics has had a terrific impact in medical imaging since this latter discipline took off in late ’70 with the invention of the CT scanners. The massive use in High Energy Physics of position sensitive gas detectors, of high Z and high density scintillators coupled to Photomultiplier (PMT) and Position Sensitive Photomultipliers (PSPMT), and of solid state detectors has triggered during the last 30 years a series of novel applications in Medical Imaging with ionizing radiation. The accelerated scientific progression in genetics and molecular biology has finally generated what it is now called Molecular Imaging. This field of research presents additional challenges not only in the technology of radiation detector, but more and more in the ASIC electronics, fast digital readout and parallel software. In this series of three lectures I will try to present how high energy physics and medical imaging development have both benefited by t...

  12. LHCb ring imaging Cherenkov detector mirrors

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    In a large dark room, men in white move around an immense structure some 7 m high, 10 m wide and nearly 2.5 m deep. Apparently effortlessly, they are installing the two large high-precision spherical mirrors. These mirrors will focus Cherenkov light, created by the charged particles that will traverse this detector, onto the photon detectors.

  13. Evaluation of XRI-UNO CdTe detector for nuclear medical imaging

    Science.gov (United States)

    Jambi, L. K.; Lees, J. E.; Bugby, S. L.; Tipper, S.; Alqahtani, M. S.; Perkins, A. C.

    2015-06-01

    Over the last two decades advances in semiconductor detector technology have reached the point where they are sufficiently sensitive to become an alternative to scintillators for high energy gamma ray detection for application in fields such as medical imaging. This paper assessed the Cadmium-Telluride (CdTe) XRI-UNO semiconductor detector produced by X-RAY Imatek for photon energies of interest in nuclear imaging. The XRI-UNO detector was found to have an intrinsic spatial resolution of <0.5mm and a high incident count rate capability up to at least 1680cps. The system spatial resolution, uniformity and sensitivity characteristics are also reported.

  14. Recent advances in CZT strip detectors and coded mask imagers

    Science.gov (United States)

    Matteson, J. L.; Gruber, D. E.; Heindl, W. A.; Pelling, M. R.; Peterson, L. E.; Rothschild, R. E.; Skelton, R. T.; Hink, P. L.; Slavis, K. R.; Binns, W. R.; Tumer, T.; Visser, G.

    1999-09-01

    The UCSD, WU, UCR and Nova collaboration has made significant progress on the necessary techniques for coded mask imaging of gamma-ray bursts: position sensitive CZT detectors with good energy resolution, ASIC readout, coded mask imaging, and background properties at balloon altitudes. Results on coded mask imaging techniques appropriate for wide field imaging and localization of gamma-ray bursts are presented, including a shadowgram and deconvolved image taken with a prototype detector/ASIC and MURA mask. This research was supported by NASA Grants NAG5-5111, NAG5-5114, and NGT5-50170.

  15. Single Photon Counting Detectors for Low Light Level Imaging Applications

    Science.gov (United States)

    Kolb, Kimberly

    2015-10-01

    This dissertation presents the current state-of-the-art of semiconductor-based photon counting detector technologies. HgCdTe linear-mode avalanche photodiodes (LM-APDs), silicon Geiger-mode avalanche photodiodes (GM-APDs), and electron-multiplying CCDs (EMCCDs) are compared via their present and future performance in various astronomy applications. LM-APDs are studied in theory, based on work done at the University of Hawaii. EMCCDs are studied in theory and experimentally, with a device at NASA's Jet Propulsion Lab. The emphasis of the research is on GM-APD imaging arrays, developed at MIT Lincoln Laboratory and tested at the RIT Center for Detectors. The GM-APD research includes a theoretical analysis of SNR and various performance metrics, including dark count rate, afterpulsing, photon detection efficiency, and intrapixel sensitivity. The effects of radiation damage on the GM-APD were also characterized by introducing a cumulative dose of 50 krad(Si) via 60 MeV protons. Extensive development of Monte Carlo simulations and practical observation simulations was completed, including simulated astronomical imaging and adaptive optics wavefront sensing. Based on theoretical models and experimental testing, both the current state-of-the-art performance and projected future performance of each detector are compared for various applications. LM-APD performance is currently not competitive with other photon counting technologies, and are left out of the application-based comparisons. In the current state-of-the-art, EMCCDs in photon counting mode out-perform GM-APDs for long exposure scenarios, though GM-APDs are better for short exposure scenarios (fast readout) due to clock-induced-charge (CIC) in EMCCDs. In the long term, small improvements in GM-APD dark current will make them superior in both long and short exposure scenarios for extremely low flux. The efficiency of GM-APDs will likely always be less than EMCCDs, however, which is particularly disadvantageous for

  16. A spark-protected high-rate detector

    Energy Technology Data Exchange (ETDEWEB)

    Fonte, P. E-mail: paulo.fonte@cern.chfonte@lipc.fis.uc.pt; Carolino, N.; Costa, L.; Ferreira-Marques, Rui; Mendiratta, S.; Peskov, V.; Policarpo, A

    1999-07-11

    We developed a very low resistivity RPC-type detector, the anode of which was a plate made from materials with resistivity up to 5x10{sup 7} {omega} cm, the cathode being a metallic mesh preceded by a drift region. In such a detector it was actually possible to combine the versatility and high counting-rate capability of metallic PPACs with the extreme robustness and 'protectiveness' of Resistive Plate Chambers. Occasional discharges triggered by large deposits of primary ionisation or by extreme counting rates are quenched by the resistive anode and are constrained to the streamer phase of the sparking process. The study shows that this discharge affects the detector only locally and that the charge released is limited to a few tens of nC. Proportional counting rates up to 10{sup 5} Hz/mm{sup 2} were achieved at gains above 10{sup 4}. The energy resolution at 6 keV was 20% FWHM. The observed gain-rate trade-off is well described by an analytic model and further improvements may be expected by lowering the resistivity of the anode material. The properties of several custom-made, controllable resistivity, anode materials are described and prospects of improvement in the performance of the detector are discussed. (author)

  17. Coincidence velocity map imaging using a single detector

    Science.gov (United States)

    Zhao, Arthur; Sándor, Péter; Weinacht, Thomas

    2017-07-01

    We demonstrate a single-detector velocity map imaging setup which is capable of rapidly switching between coincidence and non-coincidence measurements. By rapidly switching the extraction voltages on the electrostatic lenses, both electrons and ions can be collected in coincidence with a single detector. Using a fast camera as the 2D detector avoids the saturation problem associated with traditional delay line detectors and allows for easy transitions between coincidence and non-coincidence data collection modes. This is a major advantage in setting up a low-cost and versatile coincidence apparatus. We present both coincidence and non-coincidence measurements of strong field atomic and molecular ionization.

  18. Image Steganography using Hybrid Edge Detector and Ridgelet Transform

    OpenAIRE

    S.UMA MAHESWARI; D. Jude Hemanth

    2015-01-01

    Steganography is the art of hiding high sensitive information in digital image, text, video, and audio. In this paper, authors have proposed a frequency domain steganography method operating in the Ridgelet transform. Authors engage the advantage of ridgelet transform, which represents the digital image with straight edges. In the embedding phase, the proposed hybrid edge detector acts as a preprocessing step to obtain the edge image from the cover image, then the edge image is partitioned in...

  19. Neutron detection with imaging plates Part II. Detector characteristics

    CERN Document Server

    Thoms, M

    1999-01-01

    On the basis of the physical processes described in Neutron detection with imaging plates - part I: image storage and readout [Nucl. Instr. and Meth. A 424 (1999) 26-33] detector characteristics, such as quantum efficiency, detective quantum efficiency, sensitivity to neutron- and gamma-radiation, readout time and dynamic range are predicted. It is estimated that quantum efficiencies and detective quantum efficiencies close to 100% can be reached making these kind of detectors interesting for a wide range of applications.

  20. The detective quantum efficiency of an imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Zanella, G. [Padova Univ. (Italy). Dipartimento di Fisica and INFN; Zannoni, R. [Padova Univ. (Italy). Dipartimento di Fisica and INFN

    1995-05-15

    The efficiency of an imaging detector is a more extensive parameter than the quantum efficiency of a track detector or of a counter, as an image is created by the summation of many responses due to the single incoming quanta. This efficiency parameter is the so-called detective quantum efficiency (DQE). The paper illustrates the general meaning of DQE and the procedure to measure it. (orig.).

  1. Compton imaging with thick Si and CZT detectors

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Mythili, E-mail: mythili.subramanian@gmail.com [George Mason University, 4400 University Dr., Fairfax, VA 22030 (United States); Wulf, Eric A.; Phlips, Bernard [U S Naval Research Lab, 4555 Overlook Ave SW, Washington DC 20375 (United States); Krawczynski, Henric; Martin, Jerrad; Dowknott, Paul [Washington University at St. Louis, St. Louis. MO (United States)

    2012-08-01

    A Compton imaging telescope has been constructed using a 0.2 cm thick Silicon (Si) detector of active area 9.0 Multiplication-Sign 9.0 cm{sup 2} and a pixelated Cadmium Zinc Telluride (CZT) detector of dimensions 2.0 Multiplication-Sign 2.0 Multiplication-Sign 0.5 cm{sup 3}. The Si detector is double sided with 64 strips per side in two orthogonal directions. The CZT detector has 64 pixels of pitch 0.25 cm. We used several ASICs (32 channel) to read out both detectors. A {sup 137}Cs source was used in the study. The energy deposited in the Si and CZT detectors and the points of interaction of the {gamma}-ray in both detectors were read out. We varied the position of the source as well as the vertical separation between the Si and CZT detectors and measured the angular resolution of the source image for the different configurations. The best angular resolution (1{sigma}) was 2.4 Degree-Sign . Monte Carlo simulations were run for similar detector configurations and agree with the experimental results.

  2. The SUMO Ship Detector Algorithm for Satellite Radar Images

    Directory of Open Access Journals (Sweden)

    Harm Greidanus

    2017-03-01

    Full Text Available Search for Unidentified Maritime Objects (SUMO is an algorithm for ship detection in satellite Synthetic Aperture Radar (SAR images. It has been developed over the course of more than 15 years, using a large amount of SAR images from almost all available SAR satellites operating in L-, C- and X-band. As validated by benchmark tests, it performs very well on a wide range of SAR image modes (from Spotlight to ScanSAR and resolutions (from 1–100 m and for all types and sizes of ships, within the physical limits imposed by the radar imaging. This paper describes, in detail, the algorithmic approach in all of the steps of the ship detection: land masking, clutter estimation, detection thresholding, target clustering, ship attribute estimation and false alarm suppression. SUMO is a pixel-based CFAR (Constant False Alarm Rate detector for multi-look radar images. It assumes a K distribution for the sea clutter, corrected however for deviations of the actual sea clutter from this distribution, implementing a fast and robust method for the clutter background estimation. The clustering of detected pixels into targets (ships uses several thresholds to deal with the typically irregular distribution of the radar backscatter over a ship. In a multi-polarization image, the different channels are fused. Azimuth ambiguities, a common source of false alarms in ship detection, are removed. A reliability indicator is computed for each target. In post-processing, using the results of a series of images, additional false alarms from recurrent (fixed targets including range ambiguities are also removed. SUMO can run in semi-automatic mode, where an operator can verify each detected target. It can also run in fully automatic mode, where batches of over 10,000 images have successfully been processed in less than two hours. The number of satellite SAR systems keeps increasing, as does their application to maritime surveillance. The open data policy of the EU

  3. Imaging characteristics of the Extreme Ultraviolet Explorer microchannel plate detectors

    Science.gov (United States)

    Vallerga, J. V.; Kaplan, G. C.; Siegmund, O. H. W.; Lampton, M.; Malina, R. F.

    1989-01-01

    The Extreme Ultraviolet Explorer (EUVE) satellite will conduct an all-sky survey over the wavelength range from 70 A to 760 A using four grazing-incidence telescopes and seven microchannel-plate (MCP) detectors. The imaging photon-counting MCP detectors have active areas of 19.6 cm2. Photon arrival position is determined using a wedge-and-strip anode and associated pulse-encoding electronics. The imaging characteristics of the EUVE flight detectors are presented including image distortion, flat-field response, and spatial differential nonlinearity. Also included is a detailed discussion of image distortions due to the detector mechanical assembly, the wedge-and-strip anode, and the electronics. Model predictions of these distortions are compared to preflight calibration images which show distortions less than 1.3 percent rms of the detector diameter of 50 mm before correction. The plans for correcting these residual detector image distortions to less than 0.1 percent rms are also presented.

  4. A dynamic attenuator improves spectral imaging with energy-discriminating, photon counting detectors.

    Science.gov (United States)

    Hsieh, Scott S; Pelc, Norbert J

    2015-03-01

    Energy-discriminating, photon counting (EDPC) detectors have high potential in spectral imaging applications but exhibit degraded performance when the incident count rate approaches or exceeds the characteristic count rate of the detector. In order to reduce the requirements on the detector, we explore the strategy of modulating the X-ray flux field using a recently proposed dynamic, piecewise-linear attenuator. A previous paper studied this modulation for photon counting detectors but did not explore the impact on spectral applications. In this work, we modeled detection with a bipolar triangular pulse shape (Taguchi et al., 2011) and estimated the Cramer-Rao lower bound (CRLB) of the variance of material selective and equivalent monoenergetic images, assuming deterministic errors at high flux could be corrected. We compared different materials for the dynamic attenuator and found that rare earth elements, such as erbium, outperformed previously proposed materials such as iron in spectral imaging. The redistribution of flux reduces the variance or dose, consistent with previous studies on benefits with conventional detectors. Numerical simulations based on DICOM datasets were used to assess the impact of the dynamic attenuator for detectors with several different characteristic count rates. The dynamic attenuator reduced the peak incident count rate by a factor of 4 in the thorax and 44 in the pelvis, and a 10 Mcps/mm (2) EDPC detector with dynamic attenuator provided generally superior image quality to a 100 Mcps/mm (2) detector with reference bowtie filter for the same dose. The improvement is more pronounced in the material images.

  5. X-ray imaging with the PILATUS 100k detector

    DEFF Research Database (Denmark)

    Bech, Martin; Bunk, O.; David, C.;

    2008-01-01

    We report on the application of the PILATUS 100K pixel detector for medical imaging. Experimental results are presented in the form of X-ray radiographs using standard X-ray absorption contrast and a recently developed phase contrast imaging method. The results obtained with the PILATUS detector...... are compared to results obtained with a conventional X-ray imaging system consisting of an X-ray scintillation screen, lens optics, and a charge coupled device. Finally, the results for both systems are discussed more quantitatively based on an image power spectrum analysis. Udgivelsesdato: April...

  6. Image feature detectors and descriptors foundations and applications

    CERN Document Server

    Hassaballah, Mahmoud

    2016-01-01

    This book provides readers with a selection of high-quality chapters that cover both theoretical concepts and practical applications of image feature detectors and descriptors. It serves as reference for researchers and practitioners by featuring survey chapters and research contributions on image feature detectors and descriptors. Additionally, it emphasizes several keywords in both theoretical and practical aspects of image feature extraction. The keywords include acceleration of feature detection and extraction, hardware implantations, image segmentation, evolutionary algorithm, ordinal measures, as well as visual speech recognition. .

  7. Microelectronics technologies for new detectors in medical imaging

    CERN Document Server

    Heijne, Erik H M

    2007-01-01

    The use of silicon chips for instrumentation developments in elementary particle physics serves as an example for other applications and digital imaging detectors could find use in medical and molecular imaging. Attractive features are direct quantum conversion in a semiconductor matrix, innovative three-dimensional modular detector construction, multilayer devices, very fast signal processing, on-line data pre-processing and massive parallelism at the system level. Cost aspects of such semiconductor imager options have to be taken into account in the R&D phase. With the integrated electronics and high density interconnects in the Medipix development as an example, the ultimate aim of single photon imaging comes within reach.

  8. Anisotropic imaging performance in indirect x-ray imaging detectors.

    Science.gov (United States)

    Badano, Aldo; Kyprianou, Iacovos S; Sempau, Josep

    2006-08-01

    We report on the variability in imaging system performance due to oblique x-ray incidence, and the associated transport of quanta (both x rays and optical photons) through the phosphor, in columnar indirect digital detectors. The analysis uses MANTIS, a combined x-ray, electron, and optical Monte Carlo transport code freely available. We describe the main features of the simulation method and provide some validation of the phosphor screen models considered in this work. We report x-ray and electron three-dimensional energy deposition distributions and point-response functions (PRFs), including optical spread in columnar phosphor screens of thickness 100 and 500 microm, for 19, 39, 59, and 79 keV monoenergetic x-ray beams incident at 0 degrees, 10 degrees, and 15 degrees. In addition, we present pulse-height spectra for the same phosphor thickness, x-ray energies, and angles of incidence. Our results suggest that the PRF due to the phosphor blur is highly nonsymmetrical, and that the resolution properties of a columnar screen in a tomographic, or tomosynthetic imaging system varies significantly with the angle of x-ray incidence. Moreover, we find that the noise due to the variability in the number of light photons detected per primary x-ray interaction, summarized in the information or Swank factor, is somewhat independent of thickness and incidence angle of the x-ray beam. Our results also suggest that the anisotropy in the PRF is not less in screens with absorptive backings, while the noise introduced by variations in the gain and optical transport is larger. Predictions from MANTIS, after additional validation, can provide the needed understanding of the extent of such variations, and eventually, lead to the incorporation of the changes in imaging performance with incidence angle into the reconstruction algorithms for volumetric x-ray imaging systems.

  9. Experimental and theoretical performance analysis for a CMOS-based high resolution image detector.

    Science.gov (United States)

    Jain, Amit; Bednarek, Daniel R; Rudin, Stephen

    2014-03-19

    Increasing complexity of endovascular interventional procedures requires superior x-ray imaging quality. Present state-of-the-art x-ray imaging detectors may not be adequate due to their inherent noise and resolution limitations. With recent developments, CMOS based detectors are presenting an option to fulfill the need for better image quality. For this work, a new CMOS detector has been analyzed experimentally and theoretically in terms of sensitivity, MTF and DQE. The detector (Dexela Model 1207, Perkin-Elmer Co., London, UK) features 14-bit image acquisition, a CsI phosphor, 75 µm pixels and an active area of 12 cm × 7 cm with over 30 fps frame rate. This detector has two modes of operations with two different full-well capacities: high and low sensitivity. The sensitivity and instrumentation noise equivalent exposure (INEE) were calculated for both modes. The detector modulation-transfer function (MTF), noise-power spectra (NPS) and detective quantum efficiency (DQE) were measured using an RQA5 spectrum. For the theoretical performance evaluation, a linear cascade model with an added aliasing stage was used. The detector showed excellent linearity in both modes. The sensitivity and the INEE of the detector were found to be 31.55 DN/µR and 0.55 µR in high sensitivity mode, while they were 9.87 DN/µR and 2.77 µR in low sensitivity mode. The theoretical and experimental values for the MTF and DQE showed close agreement with good DQE even at fluoroscopic exposure levels. In summary, the Dexela detector's imaging performance in terms of sensitivity, linear system metrics, and INEE demonstrates that it can overcome the noise and resolution limitations of present state-of-the-art x-ray detectors.

  10. Experimental and theoretical performance analysis for a CMOS-based high resolution image detector

    Science.gov (United States)

    Jain, Amit; Bednarek, Daniel R.; Rudin, Stephen

    2014-03-01

    Increasing complexity of endovascular interventional procedures requires superior x-ray imaging quality. Present stateof- the-art x-ray imaging detectors may not be adequate due to their inherent noise and resolution limitations. With recent developments, CMOS based detectors are presenting an option to fulfill the need for better image quality. For this work, a new CMOS detector has been analyzed experimentally and theoretically in terms of sensitivity, MTF and DQE. The detector (Dexela Model 1207, Perkin-Elmer Co., London, UK) features 14-bit image acquisition, a CsI phosphor, 75 μm pixels and an active area of 12 cm x 7 cm with over 30 fps frame rate. This detector has two modes of operations with two different full-well capacities: high and low sensitivity. The sensitivity and instrumentation noise equivalent exposure (INEE) were calculated for both modes. The detector modulation-transfer function (MTF), noise-power spectra (NPS) and detective quantum efficiency (DQE) were measured using an RQA5 spectrum. For the theoretical performance evaluation, a linear cascade model with an added aliasing stage was used. The detector showed excellent linearity in both modes. The sensitivity and the INEE of the detector were found to be 31.55 DN/μR and 0.55 μR in high sensitivity mode, while they were 9.87 DN/μR and 2.77 μR in low sensitivity mode. The theoretical and experimental values for the MTF and DQE showed close agreement with good DQE even at fluoroscopic exposure levels. In summary, the Dexela detector's imaging performance in terms of sensitivity, linear system metrics, and INEE demonstrates that it can overcome the noise and resolution limitations of present state-of-the-art x-ray detectors.

  11. CMOS APS detector characterization for quantitative X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Endrizzi, Marco, E-mail: m.endrizzi@ucl.ac.uk [Dipartimento di Fisica, Università di Siena, Via Roma 56, 53100 Siena (Italy); Istituto Nazionale di Fisica Nucleare INFN, sezione di Pisa, 56127 Pisa (Italy); Oliva, Piernicola [Dipartimento di Chimica e Farmacia, Università di Sassari, via Piandanna 4, 07100 Sassari (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Cagliari, 09042 Cagliari (Italy); Golosio, Bruno [Sezione di Matematica, Fisica e Ingegneria dell' Informazione, Università di Sassari, via Piandanna 4, 07100 Sassari (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Cagliari, 09042 Cagliari (Italy); Delogu, Pasquale [Dipartimento di Fisica “E. Fermi”, Università di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Istituto Nazionale di Fisica Nucleare INFN, sezione di Pisa, 56127 Pisa (Italy)

    2013-03-01

    An X-ray Imaging detector based on CMOS Active Pixel Sensor and structured scintillator is characterized for quantitative X-ray imaging in the energy range 11–30 keV. Linearity, dark noise, spatial resolution and flat-field correction are the characteristics of the detector subject of investigation. The detector response, in terms of mean Analog-to-Digital Unit and noise, is modeled as a function of the energy and intensity of the X-rays. The model is directly tested using monochromatic X-ray beams and it is also indirectly validated by means of polychromatic X-ray-tube spectra. Such a characterization is suitable for quantitative X-ray imaging and the model can be used in simulation studies that take into account the actual performance of the detector.

  12. Photoacoustic section imaging with an integrating cylindrical detector

    Science.gov (United States)

    Gratt, Sibylle; Passler, Klaus; Nuster, Robert; Paltauf, Guenther

    2011-07-01

    A piezoelectric detector with cylindrical shape for photoacoustic section imaging is characterized. This detector is larger than the imaging object in direction of the cylinder axis, giving rise to its integrating properties. Its focal volume has the shape of a slice and the acquisition of signals for one section image requires rotation of an object about an axis perpendicular to this slice. Image reconstruction from the signals requires the application of the inverse Radon transform. It is shown that implementing the Abel transform is a suitable step in data processing, allowing speeding up the data acquisition since the scanning angle can be reduced. The resolution of the detector was estimated in directions perpendicular and parallel to the detection plane. An upper limit for the out of plane resolution is given and section images of a zebra fish are shown.

  13. Image Segmentation in Liquid Argon Time Projection Chamber Detector

    CERN Document Server

    Płoński, Piotr; Sulej, Robert; Zaremba, Krzysztof

    2015-01-01

    The Liquid Argon Time Projection Chamber (LAr-TPC) detectors provide excellent imaging and particle identification ability for studying neutrinos. An efficient and automatic reconstruction procedures are required to exploit potential of this imaging technology. Herein, a novel method for segmentation of images from LAr-TPC detectors is presented. The proposed approach computes a feature descriptor for each pixel in the image, which characterizes amplitude distribution in pixel and its neighbourhood. The supervised classifier is employed to distinguish between pixels representing particle's track and noise. The classifier is trained and evaluated on the hand-labeled dataset. The proposed approach can be a preprocessing step for reconstructing algorithms working directly on detector images.

  14. Handling high data rate detectors at Diamond Light Source

    Science.gov (United States)

    Pedersen, U. K.; Rees, N.; Basham, M.; Ferner, F. J. K.

    2013-03-01

    An increasing number of area detectors, in use at Diamond Light Source, produce high rates of data. In order to capture, store and process this data High Performance Computing (HPC) systems have been implemented. This paper will present the architecture and usage for handling high rate data: detector data capture, large volume storage and parallel processing. The EPICS area Detector frame work has been adopted to abstract the detectors for common tasks including live processing, file format and storage. The chosen data format is HDF5 which provides multidimensional data storage and NeXuS compatibility. The storage system and related computing infrastructure include: a centralised Lustre based parallel file system, a dedicated network and a HPC cluster. A well defined roadmap is in place for the evolution of this to meet demand as the requirements and technology advances. For processing the science data the HPC cluster allow efficient parallel computing, on a mixture of ×86 and GPU processing units. The nature of the Lustre storage system in combination with the parallel HDF5 library allow efficient disk I/O during computation jobs. Software developments, which include utilising optimised parallel file reading for a variety of post processing techniques, are being developed in collaboration as part of the Pan-Data EU Project (www.pan-data.eu). These are particularly applicable to tomographic reconstruction and processing of non crystalline diffraction data.

  15. A spark-protected high-rate detector

    CERN Document Server

    Fonte, Paulo J R; Costa, L; Ferreira-Marques, R; Mendiratta, S; Peskov, Vladimir; Policarpo, Armando

    1999-01-01

    We developed a very low resistivity RPC-type detector, the anode of which was a plate made from materials with resistivity up to 5x10 sup 7 OMEGA cm, the cathode being a metallic mesh preceded by a drift region. In such a detector it was actually possible to combine the versatility and high counting-rate capability of metallic PPACs with the extreme robustness and 'protectiveness' of Resistive Plate Chambers. Occasional discharges triggered by large deposits of primary ionisation or by extreme counting rates are quenched by the resistive anode and are constrained to the streamer phase of the sparking process. The study shows that this discharge affects the detector only locally and that the charge released is limited to a few tens of nC. Proportional counting rates up to 10 sup 5 Hz/mm sup 2 were achieved at gains above 10 sup 4. The energy resolution at 6 keV was 20% FWHM. The observed gain-rate trade-off is well described by an analytic model and further improvements may be expected by lowering the resistiv...

  16. Detectors for medical radioisotope imaging: demands and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, M.I. E-mail: isabel@lipc.fis.uc.pt; Chepel, V

    2004-11-01

    Radioisotope imaging is used to obtain information on biochemical processes in living organisms, being a tool of increasing importance for medical diagnosis. The improvement and expansion of these techniques depend on the progress attained in several areas, such as radionuclide production, radiopharmaceuticals, radiation detectors and image reconstruction algorithms. This review paper will be concerned only with the detector technology. We will review in general terms the present status of medical radioisotope imaging instrumentation with the emphasis put on the developments of high-resolution gamma cameras and PET detector systems for scinti-mammography and animal imaging. The present trend to combine two or more modalities in a single machine in order to obtain complementary information will also be considered.

  17. Detectors for medical radioisotope imaging: demands and perspectives

    Science.gov (United States)

    Lopes, M. I.; Chepel, V.

    2004-10-01

    Radioisotope imaging is used to obtain information on biochemical processes in living organisms, being a tool of increasing importance for medical diagnosis. The improvement and expansion of these techniques depend on the progress attained in several areas, such as radionuclide production, radiopharmaceuticals, radiation detectors and image reconstruction algorithms. This review paper will be concerned only with the detector technology. We will review in general terms the present status of medical radioisotope imaging instrumentation with the emphasis put on the developments of high-resolution gamma cameras and PET detector systems for scinti-mammography and animal imaging. The present trend to combine two or more modalities in a single machine in order to obtain complementary information will also be considered.

  18. Simulation of computed radiography with imaging plate detectors

    Energy Technology Data Exchange (ETDEWEB)

    Tisseur, D.; Costin, M. [CEA LIST, CEA Saclay 91191 Gif sur Yvette Cedex (France); Mathy, F. [CEA-LETI, Campus Minatec, F-38054, Grenoble (France); Schumm, A. [EDF R and D, 1 avenue du général de gaulle 92141 Clamart (France)

    2014-02-18

    Computed radiography (CR) using phosphor imaging plate detectors is taking an increasing place in Radiography Testing. CR uses similar equipment as conventional radiography except that the classical X-ray film is replaced by a numerical detector, called image plate (IP), which is made of a photostimulable layer and which is read by a scanning device through photostimulated luminescence. Such digital radiography has already demonstrated important benefits in terms of exposure time, decrease of source energies and thus reduction of radioprotection area besides being a solution without effluents. This paper presents a model for the simulation of radiography with image plate detectors in CIVA together with examples of validation of the model. The study consists in a cross comparison between experimental and simulation results obtained on a step wedge with a classical X-ray tube. Results are proposed in particular with wire Image quality Indicator (IQI) and duplex IQI.

  19. The Ring Imaging CHerenkov Detectors of the LHCb Experiment

    CERN Document Server

    Perego, Davide Luigi

    2012-01-01

    Particle identification is a fundamental requirement of the LHCb experiment to fulfill its physics programme. Positive hadron identification is performed by two Ring Imaging CHerenkov (RICH) detectors. This system covers the full angular acceptance of the experiment and is equipped with three Cherenkov radiators to identify particles in a wide momentum range from1 GeV/ c up to 100 GeV/ c . The Hybrid Photon Detectors (HPDs) located outside the detector acceptance provide the photon detection with 500,000 channels. Specific read–out electronics has been developed to readout and process data from the HPDs including data transmission and power distribution. The operation and performanceoftheRICHsystemare ensuredbythe constant controland monitoringoflowandhighvoltage systems,of thegas qualityandenvironmental parameters,ofthe mirror alignment,and finallyofthe detector safety. The description of the LHCb RICH is given. The experience in operating the detector at the Large Hadron Collider is presented and discusse...

  20. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy

    Science.gov (United States)

    Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

    2014-02-01

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

  1. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy.

    Science.gov (United States)

    Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

    2014-02-01

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

  2. Two-dimensional photon counting imaging detector based on PCB delay line anode

    Science.gov (United States)

    Zhu, Bingli; Bai, Yonglin; Lei, Fanpu; Bai, Xiaohong; Wang, Bo; Qin, Junjun; Cao, Weiwei; Gou, Yongsheng

    2016-11-01

    Delay line anode detector has high spatial resolution and high count rate. It has been an important technical means for single photon imaging from near earth space to deep space. A two dimensional delay line anode is designed using multilayer circuit board technology. A complete set of PCB delay line anode single photon detection system is established. The spatial resolution of the detector is theoretically analyzed. Moreover, the signal transmission characteristic of PCB delay line and the dark count rate of the detector are tested. Theoretical analysis and experimental results show that the detector spatial resolution is about 100um and the overall dark count rate is 4counts/cm2 at 2.3KV.

  3. Residual images in charged-coupled device detectors

    Science.gov (United States)

    Rest, Armin; Mündermann, Lars; Widenhorn, Ralf; Bodegom, Erik; McGlinn, T. C.

    2002-05-01

    We present results of a systematic study of persistent, or residual, images that occur in charged-coupled device (CCD) detectors. A phenomenological model for these residual images, also known as "ghosting," is introduced. This model relates the excess dark current in a CCD after exposure to the number of filled impurity sites which is tested for various temperatures and exposure times. We experimentally derive values for the cross section, density, and characteristic energy of the impurity sites responsible for the residual images.

  4. Image performance of a new amorphous selenium flat panel x-ray detector designed for digital breast tomosynthesis

    Science.gov (United States)

    Cheung, L. K.; Jing, Z.; Bogdanovich, S.; Golden, K.; Robinson, S.; Beliaevskaia, E.; Parikh, S.

    2005-04-01

    The purpose of this work is to report the performance of an amorphous selenium (a-Se) based flat-panel x-ray imager under development for application in digital breast tomosynthesis. This detector is designed to perform both in the conventional Full Field Digital Mammography (FFDM) mode and the tomosynthesis mode. The large area 24 x 29 cm detector achieves rapid image acquisition rates of up to 4 frames per second with minimal trapped charge induced effects such as ghost or lag images of previously acquired objects. In this work, a new a-Se/TFT detector layer structure is evaluated. The design uses a top conductive layer in direct contact with the a-Se x-ray detection layer. The simple structure has few layers and minimal hole and electron trapping effects. Prototype detectors were built to investigate the basic image performance of this new a-Se/TFT detector. Image signal generation, image ghosting, image lag, and detector DQE were studied. For digital mammography applications, the residual image ghosting was less than 1% at 30 seconds elapsed time. DQE, measured at a field of 5.15 V/um, showed significantly higher values over previously reported data, especially at low exposure levels. For digital breast tomosynthesis, the image lag at dynamic readout rate was < 0.6 % at 0.5-second elapsed time. A prototype tomosynthesis system is being developed utilizing this new a-Se/TFT detector.

  5. High energy X-ray photon counting imaging using linear accelerator and silicon strip detectors

    Science.gov (United States)

    Tian, Y.; Shimazoe, K.; Yan, X.; Ueda, O.; Ishikura, T.; Fujiwara, T.; Uesaka, M.; Ohno, M.; Tomita, H.; Yoshihara, Y.; Takahashi, H.

    2016-09-01

    A photon counting imaging detector system for high energy X-rays is developed for on-site non-destructive testing of thick objects. One-dimensional silicon strip (1 mm pitch) detectors are stacked to form a two-dimensional edge-on module. Each detector is connected to a 48-channel application specific integrated circuit (ASIC). The threshold-triggered events are recorded by a field programmable gate array based counter in each channel. The detector prototype is tested using 950 kV linear accelerator X-rays. The fast CR shaper (300 ns pulse width) of the ASIC makes it possible to deal with the high instant count rate during the 2 μs beam pulse. The preliminary imaging results of several metal and concrete samples are demonstrated.

  6. High energy X-ray photon counting imaging using linear accelerator and silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Y., E-mail: cycjty@sophie.q.t.u-tokyo.ac.jp [Department of Bioengineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Shimazoe, K.; Yan, X. [Department of Nuclear Engineering and Management, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Ueda, O.; Ishikura, T. [Fuji Electric Co., Ltd., Fuji, Hino, Tokyo 191-8502 (Japan); Fujiwara, T. [National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Uesaka, M.; Ohno, M. [Nuclear Professional School, the University of Tokyo, 2-22 Shirakata-shirane, Tokai, Ibaraki 319-1188 (Japan); Tomita, H. [Department of Quantum Engineering, Nagoya University, Furo, Chikusa, Nagoya 464-8603 (Japan); Yoshihara, Y. [Department of Nuclear Engineering and Management, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Takahashi, H. [Department of Bioengineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Nuclear Engineering and Management, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2016-09-11

    A photon counting imaging detector system for high energy X-rays is developed for on-site non-destructive testing of thick objects. One-dimensional silicon strip (1 mm pitch) detectors are stacked to form a two-dimensional edge-on module. Each detector is connected to a 48-channel application specific integrated circuit (ASIC). The threshold-triggered events are recorded by a field programmable gate array based counter in each channel. The detector prototype is tested using 950 kV linear accelerator X-rays. The fast CR shaper (300 ns pulse width) of the ASIC makes it possible to deal with the high instant count rate during the 2 μs beam pulse. The preliminary imaging results of several metal and concrete samples are demonstrated.

  7. Comparison of flat-panel detector and image-intensifier detector for cone-beam CT.

    Science.gov (United States)

    Baba, Rika; Konno, Yasutaka; Ueda, Ken; Ikeda, Shigeyuki

    2002-01-01

    We evaluated a flat-panel detector (FPD) (scintillator screen and a-Si photo-sensor array) for use in a cone-beam computed tomography (CT) detector and compared it with an image-intensifier detector (IID). The FPD cone-beam CT system has a higher spatial resolution than the IID system. At equal pixel sizes, the standard deviation of noise intensity of the FPD system is equal to that of the IID system. However, the circuit noise of the FPD must be reduced, especially at low doses. Our evaluations show that the FPD system has a strong potential for use as a cone-beam CT detector because of high-spatial resolution.

  8. Development and performance of a gamma-ray imaging detector

    Science.gov (United States)

    Gálvez, J. L.; Hernanz, M.; Álvarez, J. M.; La Torre, M.; Álvarez, L.; Karelin, D.; Lozano, M.; Pellegrini, G.; Ullán, M.; Cabruja, E.; Martínez, R.; Chmeissani, M.; Puigdengoles, C.

    2012-09-01

    In the last few years we have been working on feasibility studies of future instruments in the gamma-ray range, from several keV up to a few MeV. The innovative concept of focusing gamma-ray telescopes in this energy range, should allow reaching unprecedented sensitivities and angular resolution, thanks to the decoupling of collecting area and detector volume. High sensitivities are essential to perform detailed studies of cosmic explosions and cosmic accelerators, e.g., Supernovae, Classical Novae, Supernova Remnants (SNRs), Gamma-Ray Bursts (GRBs), Pulsars, Active Galactic Nuclei (AGN). In order to achieve the needed performance, a gamma-ray imaging detector with mm spatial resolution and large enough efficiency is required. In order to fulfill the combined requirement of high detection efficiency with good spatial and energy resolution, an initial prototype of a gamma-ray imaging detector based on CdTe pixel detectors is being developed. It consists of a stack of several layers of CdTe detectors with increasing thickness, in order to enhance the gamma-ray absorption in the Compton regime. A CdTe module detector lies in a 11 x 11 pixel detector with a pixel pitch of 1mm attached to the readout chip. Each pixel is bump bonded to a fan-out board made of alumina (Al2O3) substrate and routed to the corresponding input channel of the readout ASIC to measure pixel position and pulse height for each incident gamma-ray photon. We will report the main features of the gamma-ray imaging detector performance such as the energy resolution for a set of radiation sources at different operating temperatures.

  9. A model of the high count rate performance of NaI(Tl)-based PET detectors

    Energy Technology Data Exchange (ETDEWEB)

    Wear, J.A.; Karp, J.S.; Freifelder, R. [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Radiology; Mankoff, D.A. [Univ. of Washington, Seattle, WA (United States). Dept. of Radiology; Muehllehner, G. [UGM Medical Systems, Philadelphia, PA (United States)

    1998-06-01

    A detailed model of the response of large-area NaI(Tl) detectors used in PET and their triggering and data acquisition electronics has been developed. This allows one to examine the limitations of the imaging system`s performance due to degradation in the detector performance from light pile-up and deadtime from triggering and event processing. Comparisons of simulation results to measurements from the HEAD PENN-PET scanner have been performed to validate the Monte Carlo model. The model was then used to predict improvements in the high count rate performance of the HEAD PENN-PET scanner using different signal integration times, light response functions, and detectors.

  10. Background measurements from balloon-born imaging CZT detectors

    Science.gov (United States)

    Jenkins, Jonathan A.; Narita, Tomohiko; Grindlay, Jonathan E.; Bloser, Peter F.; Stahle, Carl M.; Parker, Bradford H.; Barthelmy, Scott D.

    2003-03-01

    We report detector characteristics and background measurements from two prototype imaging CdZnTe (CZT) detectors flown on a scientific balloon payload in May 2001. The detectors are both platinum-contact 10 mm × 10 mm × 5 mm CZT crystals, each with a 4 × 4 array of pixels tiling the anode. One is made from IMARAD horizontal Bridgman CZT, the other from eV Products high-pressure Bridgman CZT. Both detectors were mounted side-by-side in a flip-chip configuration and read out by a 32-channel IDE VA/TA ASIC preamp/shaper. We enclosed the detectors in the same 40o field-of-view collimator used in our previously-reported September 2000 flight. I-V curves for the detectors are diode-like, and we find that the platinum contacts adhere significantly better to the CZT surfaces than gold to previosu detectors. The detectors and instrumentation performed well in a 20-hour balloon flight on 23/24 May 2001. Although we discovered a significant instrumental background component in flight, it was possible to measure and subtract this component from the spectra. The resulting IMARAD detector background spectrum reaches ~5×10-3 counts cm-2s-1keV-1 at 100 keV and has a power-law index of ~2 at hgih energies. The eV Products detector has a similar spectrum, although there is more uncertainty in the enregy scale because of calibration complications.

  11. Gemini Planet Imager Observational Calibrations II: Detector Performance and Calibration

    CERN Document Server

    Ingraham, Patrick; Sadakuni, Naru; Ruffio, Jean-Baptiste; Maire, Jerome; Chilcote, Jeff; Larkin, James; Marchis, Franck; Galicher, Raphael; Weiss, Jason

    2014-01-01

    The Gemini Planet Imager is a newly commissioned facility instrument designed to measure the near-infrared spectra of young extrasolar planets in the solar neighborhood and obtain imaging polarimetry of circumstellar disks. GPI's science instrument is an integral field spectrograph that utilizes a HAWAII-2RG detector with a SIDECAR ASIC readout system. This paper describes the detector characterization and calibrations performed by the GPI Data Reduction Pipeline to compensate for effects including bad/hot/cold pixels, persistence, non-linearity, vibration induced microphonics and correlated read noise.

  12. KPIX a pixel detector imaging chip

    CERN Document Server

    Cadeddu, S; Caria, M

    2002-01-01

    We present a VLSI custom device, named KPIX, developed in a 0.6 mu m CMOS technology. The circuit is dedicated to readout solid-state detectors covering large areas (on the order of square centimetre) and featuring very small currents. KPIX integrates 1024 channels (current amplifiers) and 8 ADCs on a 15.5x4 mm sup 2 area. Both an analogue and digital readout are allowed, with a 10 bit amplitude resolution. Amplifiers are organized in 8 columns of 128 rows. When choosing the digital or the analogue readout, the complete set of channels can be read out in about 30 ms. The specific design of the amplification cells allows to measure very small input current levels, on the order of fractions of pico-ampere. Power consumption has also been kept at the level of 80 mu W per cell and 150 mW (peak value) in total. The specific chip architecture and geometry allow use of many KPIX circuits together in order to serve a large detector sensitive area. The KPIX structure is presented along with some measurements character...

  13. Prototype imaging Cd-Zn-Te array detector

    Energy Technology Data Exchange (ETDEWEB)

    Bloser, P.F.; Narita, T.; Grindlay, J.E. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Shah, K. [Radiation Monitoring Devices, Inc., Watertown, MA (United States)

    1998-12-31

    The authors describe initial results of their program to develop and test Cd-Zn-Te (CZT) detectors with a pixellated array readout. Their primary interest is in the development of relatively thick CZT detectors for use in astrophysical coded aperture telescopes with response extending over the energy range {approximately}10--600 keV. The coded aperture imaging configuration requires only relatively large area pixels (1--3 mm), whereas the desired high energy response requires detector thicknesses of at least 3--5 mm. They have developed a prototype detector employing a 10 x 10 x 5 mm CZT substrate and 4 x 4 pixel (1.5 mm each) readout with gold metal contacts for the pixels and continuous gold contact for the bias on the opposite detector face. This MSM contact configuration was fabricated by RMD and tested at Harvard for uniformity, efficiency and spatial as well as spectral resolution. The authors have developed an ASIC readout (IDE-VA-1) and analysis system and report results, including {approximately}4% (FWHM) energy resolution at 60 keV. A prototype design for a full imaging detector array is discussed.

  14. The HERMES dual-radiator ring imaging Cerenkov detector

    CERN Document Server

    Akopov, N Z; Bailey, K; Bernreuther, S; Bianchi, N; Capitani, G P; Carter, P; Cisbani, E; De Leo, R; De Sanctis, E; De Schepper, D; Dzhordzhadze, V; Filippone, B W; Frullani, S; Garibaldi, F; Hansen, J O; Hommez, B; Iodice, M; Jackson, H E; Jung, P; Kaiser, R; Kanesaka, J; Kowalczyk, R; Lagamba, L; Maas, A; Muccifora, V; Nappi, E; Negodaeva, K; Nowak, Wolf-Dieter; O'Connor, T; O'Neill, T G; Potterveld, D H; Ryckbosch, D; Sakemi, Y; Sato, F; Schwind, A; Shibata, T A; Suetsugu, K; Thomas, E; Tytgat, M; Urciuoli, G M; Van de Kerckhove, K; Van de Vyver, R; Yoneyama, S; Zohrabyan, H G; Zhang, L F

    2002-01-01

    The construction and use of a dual radiator Ring Imaging Cerenkov(RICH) detector is described. This instrument was developed for the HERMES experiment at DESY which emphasizes measurements of semi-inclusive deep-inelastic scattering. It provides particle identification for pions, kaons, and protons in the momentum range from 2 to 15 GeV, which is essential to these studies. The instrument uses two radiators, C4F10, a heavy fluorocarbon gas, and a wall of silica aerogel tiles. The use of aerogel in a RICH detector has only recently become possible with the development of clear, large homogeneous and hydrophobic aerogel. A lightweight mirror was constructed using a newly perfected technique to make resin-coated carbon-fiber surfaces of optical quality. The photon detector consists of 1934 photomultiplier tubes for each detector half, held in a soft steel matrix to provide shielding against the residual field of the main spectrometer magnet.

  15. The HERMES dual-radiator ring imaging Cherenkov detector

    Science.gov (United States)

    Akopov, N.; Aschenauer, E. C.; Bailey, K.; Bernreuther, S.; Bianchi, N.; Capitani, G. P.; Carter, P.; Cisbani, E.; De Leo, R.; De Sanctis, E.; De Schepper, D.; Djordjadze, V.; Filippone, B. W.; Frullani, S.; Garibaldi, F.; Hansen, J.-O.; Hommez, B.; Iodice, M.; Jackson, H. E.; Jung, P.; Kaiser, R.; Kanesaka, J.; Kowalczyk, R.; Lagamba, L.; Maas, A.; Muccifora, V.; Nappi, E.; Negodaeva, K.; Nowak, W.-D.; O'Connor, T.; O'Neill, T. G.; Potterveld, D. H.; Ryckbosch, D.; Sakemi, Y.; Sato, F.; Schwind, A.; Shibata, T.-A.; Suetsugu, K.; Thomas, E.; Tytgat, M.; Urciuoli, G. M.; Van de Kerckhove, K.; Van de Vyver, R.; Yoneyama, S.; Zohrabian, H.; Zhang, L. F.

    2002-03-01

    The construction and use of a dual radiator Ring Imaging Cherenkov (RICH) detector is described. This instrument was developed for the HERMES experiment at DESY which emphasises measurements of semi-inclusive deep-inelastic scattering. It provides particle identification for pions, kaons, and protons in the momentum range from 2 to 15 GeV, which is essential to these studies. The instrument uses two radiators, C 4F 10, a heavy fluorocarbon gas, and a wall of silica aerogel tiles. The use of aerogel in a RICH detector has only recently become possible with the development of clear, large, homogeneous and hydrophobic aerogel. A lightweight mirror was constructed using a newly perfected technique to make resin-coated carbon-fiber surfaces of optical quality. The photon detector consists of 1934 photomultiplier tubes (PMT) for each detector half, held in a soft steel matrix to provide shielding against the residual field of the main spectrometer magnet.

  16. The HERMES dual-radiator ring imaging Cherenkov detector

    CERN Document Server

    Akopov, N; Bailey, K; Bernreuther, S; Bianchi, N; Capitani, G P; Carter, P; Cisbani, E; De Leo, R; De Sanctis, E; De Schepper, D; Dzhordzhadze, V; Filippone, B W; Frullani, S; Garibaldi, F; Hansen, J O; Hommez, B; Iodice, M; Jackson, H E; Jung, P; Kaiser, R; Kanesaka, J; Kowalczyk, R; Lagamba, L; Maas, A; Muccifora, V; Nappi, E; Negodaeva, K; Nowak, Wolf-Dieter; O'Connor, T; O'Neill, T G; Potterveld, D H; Ryckbosch, D; Sakemi, Y; Sato, F; Schwind, A; Shibata, T A; Suetsugu, K; Thomas, E; Tytgat, M; Urciuoli, G M; Van De Kerckhove, K; Van De Vyver, R; Yoneyama, S; Zhang, L F; Zohrabyan, H G

    2002-01-01

    The construction and use of a dual radiator Ring Imaging Cherenkov (RICH) detector is described. This instrument was developed for the HERMES experiment at DESY which emphasises measurements of semi-inclusive deep-inelastic scattering. It provides particle identification for pions, kaons, and protons in the momentum range from 2 to 15 GeV, which is essential to these studies. The instrument uses two radiators, C sub 4 F sub 1 sub 0 , a heavy fluorocarbon gas, and a wall of silica aerogel tiles. The use of aerogel in a RICH detector has only recently become possible with the development of clear, large, homogeneous and hydrophobic aerogel. A lightweight mirror was constructed using a newly perfected technique to make resin-coated carbon-fiber surfaces of optical quality. The photon detector consists of 1934 photomultiplier tubes (PMT) for each detector half, held in a soft steel matrix to provide shielding against the residual field of the main spectrometer magnet.

  17. Fast readout of GEM detectors for medical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bucciantonio, M., E-mail: martina.bucciantonio@cern.ch [Tera Foundation, Novara (Italy); Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics, University of Bern, Bern (Switzerland); Amaldi, U.; Kieffer, R.; Malakhov, N.; Sauli, F.; Watts, D. [Tera Foundation, Novara (Italy)

    2013-08-01

    We describe the design and implementation of a fast data acquisition (DAQ) system for Gas Electron Multiplier (GEM) trackers applied to imaging and dosimetry in hadrontherapy. Within the AQUA project of the TERA foundation a prototype of Proton Range Radiography of 30×30 cm{sup 2} active area has been designed and built to provide in-beam integrated density images of the patient before treatment. It makes use of a pair of GEMs to record position and direction of protons emerging from the target. A fast data acquisition rate close to 1 MHz will allow obtaining a good resolution in-beam proton radiography in a few seconds. A dedicated fast front-end circuit for GEM detectors (GEMROC by AGH-Crakow University) is read by the FPGA based DAQ card (GR{sub D}AQ), developed by the AQUA group. The same system is under evaluation (within the ENVISION European project) to realize the in-vivo dosimetry, based on detecting secondary light particles during the treatment of the patient.

  18. Fast readout of GEM detectors for medical imaging

    Science.gov (United States)

    Bucciantonio, M.; Amaldi, U.; Kieffer, R.; Malakhov, N.; Sauli, F.; Watts, D.

    2013-08-01

    We describe the design and implementation of a fast data acquisition (DAQ) system for Gas Electron Multiplier (GEM) trackers applied to imaging and dosimetry in hadrontherapy. Within the AQUA project of the TERA foundation a prototype of Proton Range Radiography of 30×30 cm2 active area has been designed and built to provide in-beam integrated density images of the patient before treatment. It makes use of a pair of GEMs to record position and direction of protons emerging from the target. A fast data acquisition rate close to 1 MHz will allow obtaining a good resolution in-beam proton radiography in a few seconds. A dedicated fast front-end circuit for GEM detectors (GEMROC by AGH-Crakow University) is read by the FPGA based DAQ card (GR_DAQ), developed by the AQUA group. The same system is under evaluation (within the ENVISION European project) to realize the in-vivo dosimetry, based on detecting secondary light particles during the treatment of the patient.

  19. Imaging with polycrystalline mercuric iodide detectors using VLSI readout

    Energy Technology Data Exchange (ETDEWEB)

    Turchetta, R.; Dulinski, W.; Husson, D.; Riester, J.L.; Schieber, M.; Zuck, A.; Melekhov, L.; Saado, Y.; Hermon, H.; Nissenbaum, J

    1999-06-01

    Potentially low cost and large area polycrystalline mercuric iodide room-temperature radiation detectors, with thickness of 100-600 {mu}m have been successfully tested with dedicated low-noise, low-power mixed signal VLSI electronics which can be used for compact, imaging solutions. The detectors are fabricated by depositing HgI{sub 2} directly on an insulating substrate having electrodes in the form of microstrips and pixels with an upper continuous electrode. The deposition is made either by direct evaporation or by screen printing HgI{sub 2} mixed with glue such as Poly-Vinyl-Butiral. The properties of these first-generation detectors are quite uniform from one detector to another. Also for each single detector the response is quite uniform and no charge loss in the inter-electrode space have been detected. Because of the low cost and of the polycrystallinity, detectors can be potentially fabricated in any size and shape, using standard ceramic technology equipment, which is an attractive feature where low cost and large area applications are needed. The detectors which act as radiation counters have been tested with a beta source as well as in a high-energy beam of 100 GeV muons at CERN, connected to VLSI, low noise electronics. Charge collection efficiency and uniformity have been studied. The charge is efficiently collected even in the space between strips indicating that fill factors of 100% could be reached in imaging applications with direct detection of radiation. Single photon counting capability is reached with VLSI electronics. These results show the potential of this material for applications demanding position sensitive, radiation resistant, room-temperature operating radiation detectors, where position resolution is essential, as it can be found in some applications in high-energy physics, nuclear medicine and astrophysics.

  20. A GEM-based dose imaging detector with optical readout for proton radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Klyachko, A.V., E-mail: aklyachk@indiana.edu [Indiana University Cyclotron Operations, Indiana University Integrated Science and Accelerator Technology Hall, 2401 Milo. B. Sampson Ln., Bloomington, IN 47408 (United States); Moskvin, V. [Department of Radiation Oncology, School of Medicine, Indiana University, Indianapolis, IN 46202 (United States); Nichiporov, D.F.; Solberg, K.A. [Indiana University Cyclotron Operations, Indiana University Integrated Science and Accelerator Technology Hall, 2401 Milo. B. Sampson Ln., Bloomington, IN 47408 (United States)

    2012-12-01

    New techniques in proton radiation therapy and advances in beam delivery systems design such as beam scanning require accurate 2D dosimetry systems to verify the delivered dose distribution. Dose imaging detectors based on gas electron multipliers (GEMs) are capable of providing high sensitivity, improved dose measurement linearity, position resolution, fast response and accurate characterization of depth-dose distributions. In this work, we report on the development of a GEM-based dose imaging detector with optical readout using a CCD camera. A 10 Multiplication-Sign 10 cm{sup 2} detector has been tested in a 205 MeV proton beam in single- and double-GEM configurations. The detector demonstrates linearity in dose rate up to 100 Gy/min and position resolution ({sigma}) of 0.42 mm. Transverse non-uniformity of the detector response is {<=}10% before correction and the stability of the detector output throughout the day is within {+-}1%, with day-to-day reproducibility of about 10%. The depth-dose response of the detector is close to that of a wide-aperture air-filled ionization chamber and is in good agreement with Monte Carlo simulations.

  1. Image quality evaluation of linear plastic scintillating fiber array detector for X-ray imaging

    Institute of Scientific and Technical Information of China (English)

    Mohammad Mehdi NASSERI; MA Qing-Li; YIN Ze-Jie

    2004-01-01

    It is important to assess image quality, in order to ensure that the imaging system is performing optimally and also identify the weak points in an imaging system. Three parameters mostly leading to image degradation are contrast, spatial resolution and noise. There is always a trade-off between spatial resolution and signal to noise ratio,but in scintillating fiber array detectors spatial resolution is not as important as signal to noise ratio, so we paid more attention to contrast and SNR of the system. By using GEANT4 Monte Carlo detector simulation toolkit, some effective parameters of the linear plastic scintillating fiber (PSF) array as an imaging detector were investigated. Finally we show that it is possible to use this kind of detector to take CT and DR (Digital Radiography) image under certain conditions.

  2. Detection of text in images using SUSAN edge detector

    Institute of Scientific and Technical Information of China (English)

    MAO Wen-ge; ZHANG Tian-wen; WANG Li

    2005-01-01

    Text embedded in images is one of many important cues for indexing and retrieval of images and videos. In the paper, we present a novel method of detecting text aligned either horizontally or vertically, in which a pyramid structure is used to represent an image and the features of the text are extracted using SUSAN edge detector. Text regions at each level of the pyramid are identified according to the autocorrelation analysis. New techniques are introduced to split the text regions into basic ones and merge them into text lines. By evaluating the method on a set of images, we obtain a very good performance of text detection.

  3. 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.

  4. Active Pixel Detectors For Mass Spectrometry Imaging

    NARCIS (Netherlands)

    Jungmann, JH

    2012-01-01

    In the framework of this thesis, an in-vacuum, high-voltage electron and ion imaging camera was developed. The system is particularly suitable for the detection of macromolecular ions of either polarity. The new camera is successfully tested on benchmark systems as wells as biologically relevant

  5. Active Pixel Detectors For Mass Spectrometry Imaging

    NARCIS (Netherlands)

    Jungmann, JH

    2012-01-01

    In the framework of this thesis, an in-vacuum, high-voltage electron and ion imaging camera was developed. The system is particularly suitable for the detection of macromolecular ions of either polarity. The new camera is successfully tested on benchmark systems as wells as biologically relevant mac

  6. Image Steganography using Hybrid Edge Detector and Ridgelet Transform

    Directory of Open Access Journals (Sweden)

    S. Uma Maheswari

    2015-05-01

    Full Text Available Steganography is the art of hiding high sensitive information in digital image, text, video, and audio. In this paper, authors have proposed a frequency domain steganography method operating in the Ridgelet transform. Authors engage the advantage of ridgelet transform, which represents the digital image with straight edges. In the embedding phase, the proposed hybrid edge detector acts as a preprocessing step to obtain the edge image from the cover image, then the edge image is partitioned into several blocks to operate with straight edges and Ridgelet transform is applied to each block. Then, the most significant gradient vectors (or significant edges are selected to embed the secret data. The proposed method has shown the advantages of imperceptibility of the stego image is increased because the secret data is hidden in the significant gradient vector. Authors employed the hybrid edge detector to obtain the edge image, which increases the embedding capacity. Experimental results demonstrates that peak signal-to-noise (PSNR ratio of stego image generated by this method versus the cover image is guaranteed to be above 49 dB. PSNR is much higher than that of all data hiding techniques reported in the literature.Defence Science Journal, Vol. 65, No. 3, May 2015, pp.214-219, DOI: http://dx.doi.org/10.14429/dsj.65.7871

  7. DUNBID, the Delft University neutron backscattering imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Bom, V.R. [Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)]. E-mail: vb@iri.tudelft.nl; Eijk, C.W.E. van [Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Ali, M.A. [Atomic Energy Authority, Nuclear Research Center, Reactor and Neutron Physics Department, P.O. Box 13759, Abu Zabal, Cairo (Egypt)

    2005-12-01

    In the search for low-metallic land mines, the neutron backscattering technique may be applied if the soil is sufficiently dry. An advantage of this method is the speed of detection: the scanning speed may be made comparable to that of a metal detector. A two-dimensional position sensitive detector is tested to obtain an image of the back scattered thermal neutron radiation. Results of experiments using a radionuclide neutron source are presented. The on-mine to no-mine signal ratio can be improved by the application of a window on the neutron time-of-flight. Results using a pulsed neutron generator are also presented.

  8. Detectors based on silicon photomultiplier arrays for medical imaging applications

    Energy Technology Data Exchange (ETDEWEB)

    Llosa, G.; Barrio, J.; Cabello, J.; Lacasta, C.; Oliver, J. F. [Instituto de Fisica Corpuscular - IFIC-CSIC/UVEG, Valencia (Spain); Rafecas, M. [Instituto de Fisica Corpuscular - IFIC-CSIC/UVEG, Valencia (Spain); Departamento de Fisica Atomica, Molecular Y Nuclear, Universitat de Valencia, Valencia (Spain); Stankova, V.; Solaz, C. [Instituto de Fisica Corpuscular - IFIC-CSIC/UVEG, Valencia (Spain); Bisogni, M. G.; Del Guerra, A. [Universite di Pisa, INFN Pisa, Pisa (Italy)

    2011-07-01

    Silicon photomultipliers (SiPMs) have experienced a fast development and are now employed in different research fields. The availability of 2D arrays that provide information of the interaction position in the detector has had a high interest for medical imaging. Continuous crystals combined with segmented photodetectors can provide higher efficiency than pixellated crystals and very high spatial resolution. The IRIS group at IFIC is working on the development of detector heads based on continuous crystals coupled to SiPM arrays for different applications, including a small animal PET scanner in collaboration with the Univ. of Pisa and INFN Pisa, and a Compton telescope for dose monitoring in hadron therapy. (authors)

  9. Three Dimensional Digital Image Processing using Edge Detectors

    Directory of Open Access Journals (Sweden)

    John Schmeelk

    2005-11-01

    Full Text Available This paper provides an introduction to three dimensional image edge detection and its relationship to partial derivatives, convolutions and wavelets. We are especially addressing the notion of edge detection because it has far reaching applications in all areas of research to include medical research. A patient can be diagnosed as having an aneurysm by studying an angiogram. An angiogram is the visual view of the blood vessels whereby the edges are highlighted through the implementation of edge detectors. This process is completed through convolution, wavelets and matrix techniques. Some illustrations included will be vertical, horizontal, Sobel and wavelet edge detectors.

  10. Pixel hybrid photon detectors for the ring imaging Cherenkov detectors of LHCb

    CERN Document Server

    Somerville, L

    2005-01-01

    A Pixel Hybrid Photon Detector (pixel HPD) has been developed for the LHCb Ring Imaging Cherenkov (RICH) detectors. The pixel HPD is a vacuum tube with a multi-alkali photocathode, high-voltage cross- focused electron optics and an anode consisting of a silicon pixel detector bump-bonded to a CMOS readout chip; the readout chip is thus fully encapsulated in the device. The pixel HPD fulfils the stringent requirements for the RICH detectors of LHCb, combining single photon sensitivity, high signal-to-noise ratio and fast readout with an ~8cm diameter active area and an effective pixel size of 2.5mm 2.5mm at the photocathode. The performance and characteristics of two prototype pixel HPDs have been studied in laboratory measurements and in recent beam tests. The results of all measurements agree with expectations and fulfil the LHCb RICH requirements. In readiness for production of the ~500pixel HPDs for the RICH detectors, a test programme was designed and implemented to ensure component quality control at eac...

  11. Dead-time effects in microchannel-plate imaging detectors

    Science.gov (United States)

    Zombeck, Martin V.; Fraser, George W.

    1991-01-01

    The observed counting rates of microchannel plate (MCP) based detectors for high resolution observations of celestial EUV and X-ray sources vary over many orders of magnitude; the counting capability of an individual channel, however, is not high, and is associated with dead-times ranging from 0.1 msec to 1 sec. The dead-time increases with the area illuminated; attention is presently given to laboratory determinations of the count rate characteristics of a MCP detector as a function of illuminated area, and a model is developed for these results' use in the interpretation of space observations.

  12. Detector defect correction of medical images on graphics processors

    Science.gov (United States)

    Membarth, Richard; Hannig, Frank; Teich, Jürgen; Litz, Gerhard; Hornegger, Heinz

    2011-03-01

    The ever increasing complexity and power dissipation of computer architectures in the last decade blazed the trail for more power efficient parallel architectures. Hence, such architectures like field-programmable gate arrays (FPGAs) and particular graphics cards attained great interest and are consequently adopted for parallel execution of many number crunching loop programs from fields like image processing or linear algebra. However, there is little effort to deploy barely computational, but memory intensive applications to graphics hardware. This paper considers a memory intensive detector defect correction pipeline for medical imaging with strict latency requirements. The image pipeline compensates for different effects caused by the detector during exposure of X-ray images and calculates parameters to control the subsequent dosage. So far, dedicated hardware setups with special processors like DSPs were used for such critical processing. We show that this is today feasible with commodity graphics hardware. Using CUDA as programming model, it is demonstrated that the detector defect correction pipeline consisting of more than ten algorithms is significantly accelerated and that a speedup of 20x can be achieved on NVIDIA's Quadro FX 5800 compared to our reference implementation. For deployment in a streaming application with steadily new incoming data, it is shown that the memory transfer overhead of successive images to the graphics card memory is reduced by 83% using double buffering.

  13. 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.

  14. Adaptive Depth Imaging with Single-Photon Detectors

    CERN Document Server

    He, Weiji; Lin, Jie; Shen, Shanshan; Chen, Qian; Gu, Guohua; Zhou, Beibei; Zhang, Ping

    2016-01-01

    For active optical imaging, the use of single-photon detectors could greatly improve the detection sensitivity of the system. However in low light-level, traditional maximum-likelihood based imaging method needs long acquisition time to capture clear three-dimensional (3D) image. To tackle this problem, we present a novel imaging method for depth estimate, which can obtain the accurate depth image in a short acquisition time. We exploit the temporal correlations of signal and avoid building the photon-count histogram of the maximum likelihood depth estimate. Our method can efficiently distinguish signal from noise and adaptively change the dwell time of each pixel. The experiment results demonstrate that we can fast obtain the accurate depth image despite the existence of strong background noise.

  15. Imaging at soft X-ray wavelengths with high-gain microchannel plate detector systems

    Science.gov (United States)

    Timothy, J. Gethyn

    1986-01-01

    Multianode microchannel array (MAMA) detector systems with formats of 256 x 1024 pixels and active areas of 6 x 26 mm are now under evaluation at visible, UV and soft X-ray wavelengths. Very-large-format versions of the MAMA detectors with formats of 2048 x 2048 pixels and active areas of 52 x 52 mm are under development for use in the NASA Goddard Space Telescope Imaging Spectrograph (STIS). Open-structure versions of these detectors with Cs I photocathodes can provide a high-resolution imaging capability at EUV and soft X-ray wavelengths and can deliver a maximum count rate from each array in excess of 10 to the 6th counts/s. In addition, these detector systems have the unique capability to determine the arrival time of a detected photon to an accuracy of 100 ns or better. The construction, mode of operation, and performance characteristics of the MAMA detectors are described, and the program for the development of the very-large-format detectors is outlined.

  16. Imaging MAMA detector systems. [Multi-Anode Microchannel Array

    Science.gov (United States)

    Slater, David C.; Timothy, J. G.; Morgan, Jeffrey S.; Kasle, David B.

    1990-01-01

    Imaging multianode microchannel array (MAMA) detector systems with 1024 x 1024 pixel formats have been produced for visible and UV wavelengths; the UV types employ 'solar blind' photocathodes whose detective quantum efficiencies are significantly higher than those of currently available CCDs operating at far-UV and EUV wavelengths. Attention is presently given to the configurations and performance capabilities of state-of-the-art MAMA detectors, with a view to the development requirements of the hybrid electronic circuits needed for forthcoming spacecraft-sensor applications. Gain, dark noise, uniformity, and dynamic range performance data are presented for the curved-channel 'chevron', 'Z-plate', and helical-channel high gain microchannel plate configurations that are currently under evaluation with MAMA detector systems.

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

    Science.gov (United States)

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

    2009-03-21

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

  18. High resolution, two-dimensional imaging, microchannel plate detector for use on a sounding rocket experiment

    Science.gov (United States)

    Bush, Brett C.; Cotton, Daniel M.; Siegmund, Oswald H.; Chakrabarti, Supriya; Harris, Walter; Clarke, John

    1991-01-01

    We discuss a high resolution microchannel plate (MCP) imaging detector to be used in measurements of Doppler-shifted hydrogen Lyman-alpha line emission from Jupiter and the interplanetary medium. The detector is housed in a vacuum-tight stainless steel cylinder (to provide shielding from magnetic fields) with a MgF2 window. Operating at nominal voltage, the four plate configuration provides a gain of 1.2 x 10 exp 7 electrons per incident photon. The wedge-and-strip anode has two-dimensional imaging capabilities, with a resolution of 40 microns FWHM over a one centimeter diameter area. The detector has a high quantum efficiency while retaining a low background rate. A KBr photocathode is used to enhance the quantum efficiency of the bare MCPs to a value of 35 percent at Lyman-alpha.

  19. High bit rate germanium single photon detectors for 1310nm

    Science.gov (United States)

    Seamons, J. A.; Carroll, M. S.

    2008-04-01

    There is increasing interest in development of high speed, low noise and readily fieldable near infrared (NIR) single photon detectors. InGaAs/InP Avalanche photodiodes (APD) operated in Geiger mode (GM) are a leading choice for NIR due to their preeminence in optical networking. After-pulsing is, however, a primary challenge to operating InGaAs/InP single photon detectors at high frequencies1. After-pulsing is the effect of charge being released from traps that trigger false ("dark") counts. To overcome this problem, hold-off times between detection windows are used to allow the traps to discharge to suppress after-pulsing. The hold-off time represents, however, an upper limit on detection frequency that shows degradation beginning at frequencies of ~100 kHz in InGaAs/InP. Alternatively, germanium (Ge) single photon avalanche photodiodes (SPAD) have been reported to have more than an order of magnitude smaller charge trap densities than InGaAs/InP SPADs2, which allowed them to be successfully operated with passive quenching2 (i.e., no gated hold off times necessary), which is not possible with InGaAs/InP SPADs, indicating a much weaker dark count dependence on hold-off time consistent with fewer charge traps. Despite these encouraging results suggesting a possible higher operating frequency limit for Ge SPADs, little has been reported on Ge SPAD performance at high frequencies presumably because previous work with Ge SPADs has been discouraged by a strong demand to work at 1550 nm. NIR SPADs require cooling, which in the case of Ge SPADs dramatically reduces the quantum efficiency of the Ge at 1550 nm. Recently, however, advantages to working at 1310 nm have been suggested which combined with a need to increase quantum bit rates for quantum key distribution (QKD) motivates examination of Ge detectors performance at very high detection rates where InGaAs/InP does not perform as well. Presented in this paper are measurements of a commercially available Ge APD

  20. Terahertz detectors for long wavelength multi-spectral imaging.

    Energy Technology Data Exchange (ETDEWEB)

    Lyo, Sungkwun Kenneth; Wanke, Michael Clement; Reno, John Louis; Shaner, Eric Arthur; Grine, Albert D.

    2007-10-01

    The purpose of this work was to develop a wavelength tunable detector for Terahertz spectroscopy and imaging. Our approach was to utilize plasmons in the channel of a specially designed field-effect transistor called the grating-gate detector. Grating-gate detectors exhibit narrow-linewidth, broad spectral tunability through application of a gate bias, and no angular dependence in their photoresponse. As such, if suitable sensitivity can be attained, they are viable candidates for Terahertz multi-spectral focal plane arrays. When this work began, grating-gate gate detectors, while having many promising characteristics, had a noise-equivalent power (NEP) of only 10{sup -5} W/{radical}Hz. Over the duration of this project, we have obtained a true NEP of 10{sup -8} W/{radical}Hz and a scaled NEP of 10{sup -9}W/{radical}Hz. The ultimate goal for these detectors is to reach a NEP in the 10{sup -9{yields}-10}W/{radical}Hz range; we have not yet seen a roadblock to continued improvement.

  1. Prototype Imaging Cd-Zn-Te Array Detector

    CERN Document Server

    Bloser, P F; Grindlay, J E; Shah, K

    1998-01-01

    We describe initial results of our program to develop and test Cd-Zn-Te (CZT) detectors with a pixellated array readout. Our primary interest is in the development of relatively thick CZT detectors for use in astrophysical coded aperture telescopes with response extending over the energy range $\\sim 10-600$ keV. The coded aperture imaging configuration requires only relatively large area pixels (1-3 mm), whereas the desired high energy response requires detector thicknesses of at least 3-5 mm. We have developed a prototype detector employing a 10 x 10 x 5 mm CZT substrate and 4 x 4 pixel (1.5 mm each) readout with gold metal contacts for the pixels and continuous gold contact for the bias on the opposite detector face. This MSM contact configuration was fabricated by RMD and tested at Harvard for uniformity, efficiency and spatial as well as spectral resolution. We have developed an ASIC readout (IDE-VA-1) and analysis system and report results, including $\\sim 4$% (FWHM) energy resolution at 60 keV. A protot...

  2. Evaluation of cassette-based digital radiography detectors using standardized image quality metrics: AAPM TG-150 Draft Image Detector Tests.

    Science.gov (United States)

    Li, Guang; Greene, Travis C; Nishino, Thomas K; Willis, Charles E

    2016-09-08

    The purpose of this study was to evaluate several of the standardized image quality metrics proposed by the American Association of Physics in Medicine (AAPM) Task Group 150. The task group suggested region-of-interest (ROI)-based techniques to measure nonuniformity, minimum signal-to-noise ratio (SNR), number of anomalous pixels, and modulation transfer function (MTF). This study evaluated the effects of ROI size and layout on the image metrics by using four different ROI sets, assessed result uncertainty by repeating measurements, and compared results with two commercially available quality control tools, namely the Carestream DIRECTVIEW Total Quality Tool (TQT) and the GE Healthcare Quality Assurance Process (QAP). Seven Carestream DRX-1C (CsI) detectors on mobile DR systems and four GE FlashPad detectors in radiographic rooms were tested. Images were analyzed using MATLAB software that had been previously validated and reported. Our values for signal and SNR nonuniformity and MTF agree with values published by other investigators. Our results show that ROI size affects nonuniformity and minimum SNR measurements, but not detection of anomalous pixels. Exposure geometry affects all tested image metrics except for the MTF. TG-150 metrics in general agree with the TQT, but agree with the QAP only for local and global signal nonuniformity. The difference in SNR nonuniformity and MTF values between the TG-150 and QAP may be explained by differences in the calculation of noise and acquisition beam quality, respectively. TG-150's SNR nonuniformity metrics are also more sensitive to detector nonuniformity compared to the QAP. Our results suggest that fixed ROI size should be used for consistency because nonuniformity metrics depend on ROI size. Ideally, detector tests should be performed at the exact calibration position. If not feasible, a baseline should be established from the mean of several repeated measurements. Our study indicates that the TG-150 tests can be

  3. Amorphous selenium based detectors for medical imaging applications

    Science.gov (United States)

    Mandal, Krishna C.; Kang, Sung H.; Choi, Michael; Jellison, Gerald E., Jr.

    2006-08-01

    We have developed and characterized large volume amorphous (a-) selenium (Se) stabilized alloys for room temperature medical imaging devices and high-energy physics detectors. The synthesis and preparation of well-defined and high quality a-Se (B, As, Cl) alloy materials have been conducted using a specially designed alloying reactor at EIC and installed in an argon atmosphere glove box. The alloy composition has been precisely controlled and optimized to ensure good device performance. The synthesis of large volume boron (B) doped (natural and isotopic 10B) a-Se (As, Cl) alloys has been carried out by thoroughly mixing vacuum distilled and zone-refined (ZR) Se with previously synthesized Se-As master alloys, Se-Cl master alloys and B. The synthesized a-Se (B, As, Cl) alloys have been characterized by x-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier transform infra-red spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectroscopy (ICP-MS), and detector testing. The a- Se alloys have shown high promise for x-ray detectors with its high dark resistivity (10 10-10 13 Ωcm), good charge transport properties, and cost-effective large area scalability. Details of various steps about detector fabrication and testing of these imaging devices are also presented.

  4. Projection x-ray imaging with photon energy weighting: experimental evaluation with a prototype detector.

    Science.gov (United States)

    Shikhaliev, Polad M

    2009-08-21

    The signal-to-noise ratio (SNR) in x-ray imaging can be increased using a photon counting detector which could allow for rejecting electronics noise and for weighting x-ray photons according to their energies. This approach, however, was not feasible for a long time because photon counting x-ray detectors with very high count rates, good energy resolution and a large number of small pixels were required. These problems have been addressed with the advent of new detector materials, fast readout electronics and powerful computers. In this work, we report on the experimental evaluation of projection x-ray imaging with a photon counting cadmium-zinc-telluride (CZT) detector with energy resolving capabilities. The detector included two rows of pixels with 128 pixels per row with 0.9 x 0.9 mm(2) pixel size, and a 2 Mcount pixel(-1) s(-1) count rate. The x-ray tube operated at 120 kVp tube voltage with 2 mm Al-equivalent inherent filtration. The x-ray spectrum was split into five regions, and five independent x-ray images were acquired at a time. These five quasi-monochromatic x-ray images were used for x-ray energy weighting and material decomposition. A tissue-equivalent phantom was used including contrast elements simulating adipose, calcifications, iodine and air. X-ray energy weighting improved the SNR of calcifications and iodine by a factor of 1.32 and 1.36, respectively, as compared to charge integrating. Material decomposition was performed by dual energy subtraction. The low- and high-energy images were generated in the energy ranges of 25-60 keV and 60-120 keV, respectively, by combining five monochromatic image data into two. X-ray energy weighting was applied to low- and high-energy images prior to subtraction, and this improved the SNR of calcifications and iodine in dual energy subtracted images by a factor of 1.34 and 1.25, respectively, as compared to charge integrating. The detector energy resolution, spatial resolution, linearity, count rate, noise and

  5. Photon Counting Energy Dispersive Detector Arrays for X-ray Imaging.

    Science.gov (United States)

    Iwanczyk, Jan S; Nygård, Einar; Meirav, Oded; Arenson, Jerry; Barber, William C; Hartsough, Neal E; Malakhov, Nail; Wessel, Jan C

    2009-01-01

    The development of an innovative detector technology for photon-counting in X-ray imaging is reported. This new generation of detectors, based on pixellated cadmium telluride (CdTe) and cadmium zinc telluride (CZT) detector arrays electrically connected to application specific integrated circuits (ASICs) for readout, will produce fast and highly efficient photon-counting and energy-dispersive X-ray imaging. There are a number of applications that can greatly benefit from these novel imagers including mammography, planar radiography, and computed tomography (CT). Systems based on this new detector technology can provide compositional analysis of tissue through spectroscopic X-ray imaging, significantly improve overall image quality, and may significantly reduce X-ray dose to the patient. A very high X-ray flux is utilized in many of these applications. For example, CT scanners can produce ~100 Mphotons/mm(2)/s in the unattenuated beam. High flux is required in order to collect sufficient photon statistics in the measurement of the transmitted flux (attenuated beam) during the very short time frame of a CT scan. This high count rate combined with a need for high detection efficiency requires the development of detector structures that can provide a response signal much faster than the transit time of carriers over the whole detector thickness. We have developed CdTe and CZT detector array structures which are 3 mm thick with 16×16 pixels and a 1 mm pixel pitch. These structures, in the two different implementations presented here, utilize either a small pixel effect or a drift phenomenon. An energy resolution of 4.75% at 122 keV has been obtained with a 30 ns peaking time using discrete electronics and a (57)Co source. An output rate of 6×10(6) counts per second per individual pixel has been obtained with our ASIC readout electronics and a clinical CT X-ray tube. Additionally, the first clinical CT images, taken with several of our prototype photon-counting and

  6. Aging of imaging properties of a CMOS flat-panel detector for dental cone-beam computed tomography

    Science.gov (United States)

    Kim, D. W.; Han, J. C.; Yun, S.; Kim, H. K.

    2017-01-01

    We have experimentally investigated the long-term stability of imaging properties of a flat-panel detector in conditions used for dental x-ray imaging. The detector consists of a CsI:Tl layer and CMOS photodiode pixel arrays. Aging simulations were carried out using an 80-kVp x-ray beam at an air-kerma rate of approximately 5 mGy s-1 at the entrance surface of the detector with a total air kerma of up to 0.6 kGy. Dark and flood-field images were periodically obtained during irradiation, and the mean signal and noise levels were evaluated for each image. We also evaluated the modulation-transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). The aging simulation showed a decrease in both the signal and noise of the gain-offset-corrected images, but there was negligible change in the signal-to-noise performance as a function of the accumulated dose. The gain-offset correction for analyzing images resulted in negligible changes in MTF, NPS, and DQE results over the total dose. Continuous x-ray exposure to a detector can cause degradation in the physical performance factors such the detector sensitivity, but linear analysis of the gain-offset-corrected images can assure integrity of the imaging properties of a detector during its lifetime.

  7. Imaging Hybrid Photon Detectors with a Reflective Photocathode

    CERN Document Server

    Ferenc, D

    2000-01-01

    Modern epitaxially grown photocathodes, like GaAsP, bring a very high inherent quantum efficiency, but are rather expensive due to the complicated manufacturing and mounting process. We argue that such photocathodes could be used in reflective mode, in order to avoid the risky and expensive removal of the epitaxial growth substrate. Besides that the quantum efficiency should increase considerably. In this paper we present results of the development of large imaging Hybrid Photon Detectors (HPDs), particularly designed for such reflective photocathodes.

  8. Dose rate and SDD dependence of commercially available diode detectors.

    Science.gov (United States)

    Saini, Amarjit S; Zhu, Timothy C

    2004-04-01

    The dose-rate dependence of commercially available diode detectors was measured under both high instantaneous dose-rate (pulsed) and low dose rate (continuous, Co-60) radiation. The dose-rate dependence was measured in an acrylic miniphantom at a 5-cm depth in a 10 x 10 cm2 collimator setting, by varying source-to-detector distance (SDD) between at least 80 and 200 cm. The ratio of a normalized diode reading to a normalized ion chamber reading (both at SDD=100 cm) was used to determine diode sensitivity ratio for pulsed and continuous radiation at different SDD. The inverse of the diode sensitivity ratio is defined as the SDD correction factor (SDD CF). The diode sensitivity ratio increased with increasing instantaneous dose rate (or decreasing SDD). The ratio of diode sensitivity, normalized to 4000 cGy/s, varied between 0.988 (1490 cGy/s)-1.023 (38,900 cGy/s) for unirradiated n-type Isorad Gold, 0.981 (1460 cGy/s)-1.026 (39,060 cGy/s) for unirradiated QED Red (n type), 0.972 (1490 cGy/s)-1.068 (38,900 cGy/s) for preirradiated Isorad Red (n type), 0.985 (1490 cGy/s)-1.012 (38,990 cGy/s) for n-type Pt-doped Isorad-3 Gold, 0.995 (1450 cGy/s)-1.020 (21,870 cGy/s) for n-type Veridose Green, 0.978 (1450 cGy/s)-1.066 (21,870 cGy/s) for preirradiated Isorad-p Red, 0.994 (1540 cGy/s)-1.028 (17,870 cGy/s) for p-type preirradiated QED, 0.998 (1450 cGy/s)-1.003 (21,870 cGy/s) for the p-type preirradiated Scanditronix EDP20(3G), and 0.998 (1490 cGy/s)-1.015 (38,880 cGy/s) for Scanditronix EDP10(3G) diodes. The p-type diodes do not always show less dose-rate dependence than the n-type diodes. Preirradiation does not always reduce diode dose-rate dependence. A comparison between the SDD dependence measured at the surface of a full scatter phantom and that in a miniphantom was made. Using a direct adjustment of radiation pulse height, we concluded that the SDD dependence of diode sensitivity can be explained by the instantaneous dose-rate dependence if sufficient buildup is

  9. A minimum bit error-rate detector for amplify and forward relaying systems

    KAUST Repository

    Ahmed, Qasim Zeeshan

    2012-05-01

    In this paper, a new detector is being proposed for amplify-and-forward (AF) relaying system when communicating with the assistance of L number of relays. The major goal of this detector is to improve the bit error rate (BER) performance of the system. The complexity of the system is further reduced by implementing this detector adaptively. The proposed detector is free from channel estimation. Our results demonstrate that the proposed detector is capable of achieving a gain of more than 1-dB at a BER of 10 -5 as compared to the conventional minimum mean square error detector when communicating over a correlated Rayleigh fading channel. © 2012 IEEE.

  10. Breast cancer detection rates using four different types of mammography detectors

    Energy Technology Data Exchange (ETDEWEB)

    Mackenzie, Alistair; Warren, Lucy M.; Dance, David R.; Young, Kenneth C. [Royal Surrey County Hospital, National Coordinating Centre for the Physics in Mammography (NCCPM), Guildford (United Kingdom); University of Surrey, Department of Physics, Guildford (United Kingdom); Wallis, Matthew G. [Cambridge University Hospitals NHS Foundation Trust, Cambridge (United Kingdom); NIHR Cambridge Biomedical Research Centre, Cambridge Breast Unit, Cambridge (United Kingdom); Cooke, Julie [Jarvis Breast Screening and Diagnostic Centre, Guildford (United Kingdom); Given-Wilson, Rosalind M. [St George' s Healthcare NHS Trust, Department of Radiology, London (United Kingdom); Chakraborty, Dev P. [University of Pittsburgh, Department of Radiology, Pittsburgh, PA (United States); Halling-Brown, Mark D. [Royal Surrey County Hospital, Scientific Computing, Department of Medical Physics, Guildford (United Kingdom); Looney, Padraig T. [Royal Surrey County Hospital, National Coordinating Centre for the Physics in Mammography (NCCPM), Guildford (United Kingdom)

    2016-03-15

    To compare the performance of different types of detectors in breast cancer detection. A mammography image set containing subtle malignant non-calcification lesions, biopsy-proven benign lesions, simulated malignant calcification clusters and normals was acquired using amorphous-selenium (a-Se) detectors. The images were adapted to simulate four types of detectors at the same radiation dose: digital radiography (DR) detectors with a-Se and caesium iodide (CsI) convertors, and computed radiography (CR) detectors with a powder phosphor (PIP) and a needle phosphor (NIP). Seven observers marked suspicious and benign lesions. Analysis was undertaken using jackknife alternative free-response receiver operating characteristics weighted figure of merit (FoM). The cancer detection fraction (CDF) was estimated for a representative image set from screening. No significant differences in the FoMs between the DR detectors were measured. For calcification clusters and non-calcification lesions, both CR detectors' FoMs were significantly lower than for DR detectors. The calcification cluster's FoM for CR NIP was significantly better than for CR PIP. The estimated CDFs with CR PIP and CR NIP detectors were up to 15 % and 22 % lower, respectively, than for DR detectors. Cancer detection is affected by detector type, and the use of CR in mammography should be reconsidered. (orig.)

  11. 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.

  12. Development of the microstrip silicon detector for imaging of fast processes at a synchrotron radiation beam

    Science.gov (United States)

    Aulchenko, V.; Pruuel, E.; Shekhtman, L.; Ten, K.; Tolochko, B.; Zhulanov, V.

    2017-02-01

    In situ imaging of explosions allows to study material properties under very high pressures and temperatures. Synchrotron radiation (SR) is a powerful tool for such studies because of its unique time structure. Flashes of X-rays from individual bunches in a storage ring are so short that an object under study does not move more than 1-10 μm during exposure. If a detector is able to store images synchronously with bunches of an SR source the time resolution of such method will be determined by the duration of SR flash from individual bunch. New beam line at the VEPP-4M storage ring will allow to get X-Ray flux from each bunch close to 106 photons/channel where channel area is 0.05×0.5 mm2 and average beam energy is about 30 keV. Bunches in the machine can be grouped into trains with 20 ns time gap. In order to meet these requirements a new detector development was started based on Si microstrip technology. The detector with a new dedicated front-end chip will be able to record images with maximum signal equivalent to 106 photons/channel, with signal to noise ratio of ∼103, spatial resolution of 50 μm and maximum frame rate of 50 MHz. The detector has to drive very high peak and average currents without affecting the front-end chip, therefore a specific design of Si sensor should be developed. The front-end chip has to provide signal measurements with the dynamic range of about 104 or more and recording of the signal to an analogue memory with the rate of 50 MHz. The concept of such detector is discussed in the paper. The results of the simulations of the main detector parameters and the results of the first measurements with the prototype sensors are presented.

  13. Megapixel digital InSb detector for midwave infrared imaging

    Science.gov (United States)

    Shkedy, Lior; Markovitz, Tuvy; Calahorra, Zipi; Hirsh, Itay; Shtrichman, Itay

    2011-06-01

    Since the late 1990s Semiconductor devices (SCDs) has developed and manufactured a variety of InSb two-dimensional (2D) focal plane arrays (FPAs) that were implemented in many infrared (IR) systems and applications. SCD routinely manufactures both analog and digital InSb FPAs with array formats of 320×256, 480×384, and 640×512 elements, and pitch size in the range 15 to 30 μm. These FPAs are available in many packaging configurations, including fully integrated detector-Dewar-cooler-assembly, with either closed-cycle Stirling or open-loop Joule-Thomson coolers. In response to a need for very high resolution midwave IR (MWIR) detectors and systems, SCD has developed a large format 2D InSb detector with 1280×1024 elements and pixel size of 15 μm. A digital readout integrated circuit (ROIC) is coupled by flip-chip bonding to the megapixel InSb array. The ROIC is fabricated in CMOS 0.18-μm technology, that enables the small pixel circuitry and relatively low power generation at the focal plane. The digital ROIC has an analog to digital (A/D) converter per-channel and allows for full frame readout at a rate of 100 Hz. Such on-chip A/D conversion eliminates the need for several A/D converters with fairly high power consumption at the system level. The digital readout, together with the InSb detector technology, lead to a wide linear dynamic range and low residual nonuniformity, which is stable over a long period of time following a nonuniformity correction procedure. A special Dewar was designed to withstand harsh environmental conditions while minimizing the contribution to the heat load of the detector. The Dewar together with the low power ROIC, enable a megapixel detector with overall low size, weight, and power with respect to comparable large format detectors. A variety of applications with this detector make use of different cold shields with different f-number and spectral filters. In this paper we present actual performance characteristics of the

  14. Development of a gaseous photon detector for Cherenkov imaging applications

    CERN Document Server

    Rocco, Elena; Dalla Torre, Silvia

    2010-01-01

    This thesis is dedicated to the R&D activity aiming at a novel micro pattern gaseous photon detector based on the THick Gas Electron Multiplier (THGEM). The goal application of the novel photon detector is the detection of single photon in Ring Imaging CHerenkov (RICH) counters. The THGEM principle is derived from the Gas Electron Multiplier (GEM) one, even if the material, the production technology and the size scale are different: a THGEM is a Circuit Printed Board (PCB) coated with thin copper layers on both faces, with holes obtained by drilling. Part of the THGEM features are similar to those of the GEMs, but a number of characteristics aspects result substantially different: in fact, if the geometrical parameters can be scaled from the GEM ones, the parameters related to the electrons multiplication, which is a microscopic physical phenomenon, do not. This is why, before starting the photon detector development, we have performed a systematic study of the THGEM multiplier. A photon detector is forme...

  15. MCP detector read out with a bare quad Timepix at kilohertz frame rates

    Science.gov (United States)

    Vallerga, J.; Raffanti, R.; Tremsin, A.; McPhate, J.; Siegmund, O.

    2011-01-01

    The existing Berkeley neutron sensitive MCP/Timepix hybrid detector has been very successful at demonstrating energy resolved spatial imaging with a single Timepix ASIC read out at a ~ 30 Hz frame rate where each neutron's position and time (energy) is determined (X,Y,E). By increasing the detector format using a quad arrangement of Timepix readouts and increasing the frame rate to 1 kHz, we can increase our total event throughput by a factor of 120, thereby taking full advantage of the high fluxes of modern pulsed neutron sources (106 n cm-2 s-1). The key to this conversion is a new design for the ASIC readout, called the Berkeley Quad Timepix detector, consisting of 3 major subsystems. The first is a quad (2 × 2) bare Timepix ASIC board mounted directly behind the neutron sensitive MCPs in a hermetic vacuum enclosure with a sapphire window. The data from the Timepix ASICs flow to the second subsystem called the Interface board whose field programmable gate array (FPGA) rearranges and converts the digital bit stream to LVDS logic levels before sending downstream to the third subsystem, the Roach board. The Roach board is also FPGA based, and takes the data from all the ASICs and analyses the frames to extract information on the input events to pass on to the host PC. This paper describes in detail the hardware and firmware designs to accomplish this task.

  16. High frame rate synthetic aperture duplex imaging

    DEFF Research Database (Denmark)

    Stuart, Matthias Bo; Tomov, Borislav Gueorguiev; Pihl, Michael Johannes

    2013-01-01

    aperture flow imaging as demonstrated in this paper. Synthetic aperture, directional beamforming, and cross-correlation are used to produce B-mode and vector velocity images at high frame rates. The frame rate equals the effective pulse repetition frequency of each imaging mode. Emissions for making the B...

  17. Sparse Detector Imaging Sensor with Two-Class Silhouette Classification

    Directory of Open Access Journals (Sweden)

    David Russomanno

    2008-12-01

    Full Text Available This paper presents the design and test of a simple active near-infrared sparse detector imaging sensor. The prototype of the sensor is novel in that it can capture remarkable silhouettes or profiles of a wide-variety of moving objects, including humans, animals, and vehicles using a sparse detector array comprised of only sixteen sensing elements deployed in a vertical configuration. The prototype sensor was built to collect silhouettes for a variety of objects and to evaluate several algorithms for classifying the data obtained from the sensor into two classes: human versus non-human. Initial tests show that the classification of individually sensed objects into two classes can be achieved with accuracy greater than ninety-nine percent (99% with a subset of the sixteen detectors using a representative dataset consisting of 512 signatures. The prototype also includes a Webservice interface such that the sensor can be tasked in a network-centric environment. The sensor appears to be a low-cost alternative to traditional, high-resolution focal plane array imaging sensors for some applications. After a power optimization study, appropriate packaging, and testing with more extensive datasets, the sensor may be a good candidate for deployment in vast geographic regions for a myriad of intelligent electronic fence and persistent surveillance applications, including perimeter security scenarios.

  18. ASIC for High Rate 3D Position Sensitive Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, E.; De Geronimo, G.; Ackley, K.; Fried, J.; He, Z.; Herman, C.; Zhang, F.

    2010-06-16

    We report on the development of an application specific integrated circuit (ASIC) for 3D position sensitive detectors (3D PSD). The ASIC is designed to operate with pixelated wide bandgap sensors like Cadmium-Zinc-Telluride (CZT), Mercuric Iodide (Hgl2) and Thallium Bromide (TIBr). It measures the amplitudes and timings associated with an ionizing event on 128 anodes, the anode grid, and the cathode. Each channel provides low-noise charge amplification, high-order shaping with peaking time adjustable from 250 ns to 12 {micro}s, gain adjustable to 20 mV/fC or 120 mV/fC (for a dynamic range of 3.2 MeV and 530 keV in CZT), amplitude discrimination with 5-bit trimming, and positive and negative peak and timing detections. The readout can be full or sparse, based on a flag and single- or multi-cycle token passing. All channels, triggered channels only, or triggered with neighbors can be read out thus increasing the rate capability of the system to more than 10 kcps. The ASIC dissipates 330 mW which corresponds to about 2.5 mW per channel.

  19. Recent developments in X-ray imaging detectors

    CERN Document Server

    Moy, J P

    2000-01-01

    The replacement of the radiographic film in medical imaging has been the driving force in X-ray imaging developments. It requires a approx 40 cm wide detector to cover all examinations, an equivalent noise level of 1-5 X-ray quanta per pixel, and spatial resolution in the range 100-150 mu m. The need for entirely electronic imaging equipments has fostered the development of many X-ray detectors, most of them based on an array of amorphous silicon pixels, which is the only technology capable to achieve such large areas. Essentially, two concepts have been implemented: - intermediate conversion of X-rays to light by a scintillator, detected by an array of light sensitive pixels, comprising a photodiode and a switching device, either a TFT or a diode. - conversion into electron-hole pairs in a photoconductor, collected by an array of electrodes and switches. In both cases, charge amplifiers read the generated charges line by line. Scintillator and photoconductor-based systems are now close to production. They ac...

  20. High gain multigap avalanche detectors for Cerenkov ring imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gilmore, R.S.; Lavender, W.M.; Leith, D.W.G.S.; Williams, S.H.

    1980-10-01

    We report on a continuing study of multigap parallel plate avalanche chambers, primarily as photoelectron detectors for use with Cerenkov ring imaging counters. By suitable control of the fields in successive gaps and by introducing screens to reduce photon feedback to the cathode the gain many be increased considerably. We have obtained gains in excess of 6 x 10/sup 7/ for photoelectrons with a good pulse height spectrum and expect to increase this further. We discuss the use of resistive anodes to give avalanche positions in two dimensions by charge division.

  1. Advanced Scintillator Detectors for Neutron Imaging in Inertial Confinement Fusion

    Science.gov (United States)

    Geppert-Kleinrath, Verena; Danly, Christopher; Merrill, Frank; Simpson, Raspberry; Volegov, Petr; Wilde, Carl

    2016-10-01

    The neutron imaging team at Los Alamos National Laboratory (LANL) has been providing two-dimensional neutron imaging of the inertial confinement fusion process at the National Ignition Facility (NIF) for over five years. Neutron imaging is a powerful tool in which position-sensitive detectors register neutrons emitted in the fusion reactions, producing a picture of the burning fuel. Recent images have revealed possible multi-dimensional asymmetries, calling for additional views to facilitate three-dimensional imaging. These will be along shorter lines of sight to stay within the existing facility at NIF. In order to field imaging capabilities equivalent to the existing system several technological challenges have to be met: high spatial resolution, high light output, and fast scintillator response to capture lower-energy neutrons, which have scattered from non-burning regions of fuel. Deuterated scintillators are a promising candidate to achieve the timing and resolution required; a systematic study of deuterated and non-deuterated polystyrene and liquid samples is currently ongoing. A test stand has been implemented to measure the response function, and preliminary data on resolution and light output have been obtained at the LANL Weapons Neutrons Research facility.

  2. The current progress of the ALICE Ring Imaging Cherenkov Detector

    CERN Document Server

    Braem, André; Davenport, M; Mauro, A D; Franco, A; Gallas, A; Hoedlmoser, H; Martinengo, P; Nappi, E; Paic, G; Piuz, François; Peskov, Vladimir

    2007-01-01

    Recently, the last two modules (out of seven) of the ALICE High Momentum Particle Identification detector (HMPID) were assembled and tested. The full detector, after a pre-commissioning phase, has been installed in the experimental area, inside the ALICE solenoid, at the end of September 2006. In this paper we review the status of the ALICE/HMPID project and we present a summary of the series production of the CsI photo-cathodes. We describe the key features of the production procedure which ensures high quality photo-cathodes as well as the results of the quality assessment performed by means of a specially developed 2D scanner system able to produce a detailed map of the CsI photo-current over the entire photo-cathode surface. Finally we present our recent R&D efforts toward the development of a novel generation of imaging Cherenkov detectors with the aim to identify, in heavy ions collisions, hadrons up to 30 GeV/c.

  3. Development of gas microstrip detectors for digital x-ray imaging and radiation dosimetry

    CERN Document Server

    Dixit, M S; Dubeau, J; Gobbi, D G; Johns, P C; Karlen, Dean A; Oakham, F G; Waker, A J

    1998-01-01

    Our recent work in the application of gas microstrip detector (GMD) technology to the fields of digital X-ray imaging and radiation dosimetry Is described. The GMD can measure the position and the energy of individual photons at the high counting rates encountered in X-ray imaging. GMD-based imaging systems have high detective quantum efficiency and permit improvement of image quality and contrast using display windowing and measured energy information. Results are presented on the performance of a prototype GMD imaging system operated with a xenon/methane 90/10 gas mixture at 1 atm. Results are also presented on the performance of a GMD filled with tissue equivalent gases for applications in the field of radiation dosimetry in mixed neutron and gamma fields. The results show that the GMD can be used for dosimetric discrimination between different types of radiation in mixed-field environments.

  4. Cadmium Telluride Semiconductor Detector for Improved Spatial and Energy Resolution Radioisotopic Imaging.

    Science.gov (United States)

    Abbaspour, Samira; Mahmoudian, Babak; Islamian, Jalil Pirayesh

    2017-01-01

    The detector in single-photon emission computed tomography has played a key role in the quality of the images. Over the past few decades, developments in semiconductor detector technology provided an appropriate substitution for scintillation detectors in terms of high sensitivity, better energy resolution, and also high spatial resolution. One of the considered detectors is cadmium telluride (CdTe). The purpose of this paper is to review the CdTe semiconductor detector used in preclinical studies, small organ and small animal imaging, also research in nuclear medicine and other medical imaging modalities by a complete inspect on the material characteristics, irradiation principles, applications, and epitaxial growth method.

  5. X-ray imaging with a silicon microstrip detector coupled to the RX64 ASIC

    Energy Technology Data Exchange (ETDEWEB)

    Baldazzi, G.; Bollini, D.; Cabal Rodriguez, A.E.; Dabrowski, W.; Diaz Garcia, A.; Gambaccini, M.; Giubellino, P.; Gombia, M.; Grybos, P.; Idzik, M.; Marzari-Chiesa, A.; Montano Zetina, L.M.; Prino, F.; Ramello, L. E-mail: ramello@to.infn.it; Sitta, M.; Swientek, K.; Taibi, A.; Tuffanelli, A.; Wheadon, R.; Wiacek, P

    2003-08-21

    A single photon counting X-ray imaging system, with possible applications to dual energy mammography and angiography, is presented. A silicon microstrip detector with 100 {mu}m pitch strips is coupled to RX64 ASICs, each of them including 64 channels of preamplifier, shaper, discriminator and scaler. The system has low noise, good spatial resolution and high counting rate capability. Results on energy resolution have been obtained with a fluorescence source and quasi-monochromatic X-rays beams. Preliminary images obtained with an angiographic phantom are presented.

  6. Application of imaging plate neutron detector to neutron radiography

    CERN Document Server

    Fujine, S; Kamata, M; Etoh, M

    1999-01-01

    As an imaging plate neutron detector (IP-ND) has been available for thermal neutron radiography (TNR) which has high resolution, high sensitivity and wide range, some basic characteristics of the IP-ND system were measured at the E-2 facility of the KUR. After basic performances of the IP were studied, images with high quality were obtained at a neutron fluence of 2 to 7x10 sup 8 n cm sup - sup 2. It was found that the IP-ND system with Gd sub 2 O sub 3 as a neutron converter material has a higher sensitivity to gamma-ray than that of a conventional film method. As a successful example, clear radiographs of the flat view for the fuel side plates with boron burnable poison were obtained. An application of the IP-ND system to neutron radiography (NR) is presented in this paper.

  7. High-density scintillating glasses for a proton imaging detector

    Science.gov (United States)

    Tillman, I. J.; Dettmann, M. A.; Herrig, V.; Thune, Z. L.; Zieser, A. J.; Michalek, S. F.; Been, M. O.; Martinez-Szewczyk, M. M.; Koster, H. J.; Wilkinson, C. J.; Kielty, M. W.; Jacobsohn, L. G.; Akgun, U.

    2017-06-01

    High-density scintillating glasses are proposed for a novel proton-imaging device that can improve the accuracy of the hadron therapy. High-density scintillating glasses are needed to build a cost effective, compact calorimeter that can be attached to a gantry. This report summarizes the study on Europium, Terbium, and Cerium-doped scintillating glasses that were developed containing heavy elements such as Lanthanum, Gadolinium, and Tungsten. The density of the samples reach up to 5.9 g/cm3, and their 300-600 nm emission overlaps perfectly with the peak cathode sensitivity of the commercial photo detectors. The developed glasses do not require any special quenching and can be poured easily, which makes them a good candidate for production in various geometries. Here, the glass making conditions, preliminary tests on optical and physical properties of these scintillating, high-density, oxide glasses developed for a novel medical imaging application are reported.

  8. Laser system for testing radiation imaging detector circuits

    Science.gov (United States)

    Zubrzycka, Weronika; Kasinski, Krzysztof

    2015-09-01

    Performance and functionality of radiation imaging detector circuits in charge and position measurement systems need to meet tight requirements. It is therefore necessary to thoroughly test sensors as well as read-out electronics. The major disadvantages of using radioactive sources or particle beams for testing are high financial expenses and limited accessibility. As an alternative short pulses of well-focused laser beam are often used for preliminary tests. There are number of laser-based devices available on the market, but very often their applicability in this field is limited. This paper describes concept, design and validation of laser system for testing silicon sensor based radiation imaging detector circuits. The emphasis is put on keeping overall costs low while achieving all required goals: mobility, flexible parameters, remote control and possibility of carrying out automated tests. The main part of the developed device is an optical pick-up unit (OPU) used in optical disc drives. The hardware includes FPGA-controlled circuits for laser positioning in 2 dimensions (horizontal and vertical), precision timing (frequency and number) and amplitude (diode current) of short ns-scale (3.2 ns) light pulses. The system is controlled via USB interface by a dedicated LabVIEW-based application enabling full manual or semi-automated test procedures.

  9. Imaging with SiPMs in noble-gas detectors

    CERN Document Server

    Yahlali, N; González, K; Garcia, A N C; Soriano, A

    2012-01-01

    Silicon photomultipliers (SiPMs) are photosensors widely used for imaging in a variety of high energy and nuclear physics experiments. In noble-gas detectors for double-beta decay and dark matter experiments, SiPMs are attractive photosensors for imaging but they are insensitive to the VUV scintillation emitted by the noble gases (xenon and argon). This difficulty is overcome in the NEXT experiment by coating the SiPMs with tetraphenyl butadiene (TPB) to convert the VUV light into visible light. TPB requires stringent storage and operational conditions to prevent its degradation by environmental agents. The development of UV sensitive SiPMs is thus of utmost interest for experiments using UV light and for noble-gas detectors. It is in particular an important issue for a robust and background free neutrinoless double-beta decay experiment with xenon gas aimed by NEXT. The photon detection efficiency (PDE) of UV-enhanced SiPMs without protective window and with silicon resin window provided by Hamamatsu was det...

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

    NARCIS (Netherlands)

    Jungmann, JH; Heeren, R.M.A.

    2013-01-01

    Instrumental developments for imaging and individual particle detection for biomolecular mass spectrometry (imaging) and fundamental atomic and molecular physics studies are reviewed. Ion-counting detectors, array detection systems and highmass detectors for mass spectrometry (imaging) are treated.

  11. Calibration of photon counting imaging microchannel plate detectors for EUV astronomy

    Science.gov (United States)

    Siegmund, O. H. W.; Vallerga, J.; Jelinsky, P.

    1986-01-01

    The calibration of photon counting imaging detectors for satellite based EUV astronomy is a complex process designed to ensure the validity of the data received 'in orbit'. The methods developed to accomplish calibration of microchannel plate detectors for the Extreme Ultraviolet Explorer are described and illustrated. The characterization of these detectors can be subdivided into three categories: stabilization, performance tests, and environmental tests.

  12. High Spatial Resolution Investigations of Microchannel Plate Imaging Properties for UV Detectors

    Science.gov (United States)

    Siegmund, Oswald

    1996-01-01

    Microchannel plate (MCP) photon counting detectors are currently being used with great success on many of the recent NASA/ESA ultraviolet (UV) astrophysics missions that make observations in the 1OO A - 1600 A range. These include HUT, the Wide Field Camera on ROSAT, EUVE, ALEXIS, ORFEUS, and SOHO. These devices have also been chosen to fly on future UV astrophysics missions such as FUSE, FUVITA, IMAGE, and both the HST STIS and Advanced Camera instruments. During the period of this award we have fabricated a dual-chamber vacuum test facility to carry out laboratory testing of detector resolution, image stability and linearity, and flat field performance to enable us to characterize the performance of MCPs and their associated read-out architectures. We have also fabricated and tested a laboratory 'test-bed' delay line detector, which can accommodate MCP's with a wide range of formats and run at high data rates, to continue our studies of MCP image fixed pattern noise, and particularly for new small pore MCP's which have recently come onto the market. These tests were mainly focussed on the assessment of cross delay-line (XDL) and double delay line (DDL) anode read-out schemes, with particular attention being focussed on flat-field and spatial resolution performance.

  13. SWIR Geiger-mode APD detectors and cameras for 3D imaging

    Science.gov (United States)

    Itzler, Mark A.; Entwistle, Mark; Krishnamachari, Uppili; Owens, Mark; Jiang, Xudong; Slomkowski, Krystyna; Rangwala, Sabbir

    2014-06-01

    The operation of avalanche photodiodes in Geiger mode by arming these detectors above their breakdown voltage provides high-performance single photon detection in a robust solid-state device platform. Moreover, these devices are ideally suited for integration into large format focal plane arrays enabling single photon imaging. We describe the design and performance of short-wave infrared 3D imaging cameras with focal plane arrays (FPAs) based on Geigermode avalanche photodiodes (GmAPDs) with single photon sensitivity for laser radar imaging applications. The FPA pixels incorporate InP/InGaAs(P) GmAPDs for the detection of single photons with high efficiency and low dark count rates. We present results and attributes of fully integrated camera sub-systems with 32 × 32 and 128 × 32 formats, which have 100 μm pitch and 50 μm pitch, respectively. We also address the sensitivity of the fundamental GmAPD detectors to radiation exposure, including recent results that correlate detector active region volume to sustainable radiation tolerance levels.

  14. sCMOS detector for imaging VNIR spectrometry

    Science.gov (United States)

    Eckardt, Andreas; Reulke, Ralf; Schwarzer, Horst; Venus, Holger; Neumann, Christian

    2013-09-01

    The facility Optical Information Systems (OS) at the Robotics and Mechatronics Center of the German Aerospace Center (DLR) has more than 30 years of experience with high-resolution imaging technology. This paper shows the scientific results of the institute of leading edge instruments and focal plane designs for EnMAP VIS/NIR spectrograph. EnMAP (Environmental Mapping and Analysis Program) is one of the selected proposals for the national German Space Program. The EnMAP project includes the technological design of the hyper spectral space borne instrument and the algorithms development of the classification. The EnMAP project is a joint response of German Earth observation research institutions, value-added resellers and the German space industry like Kayser-Threde GmbH (KT) and others to the increasing demand on information about the status of our environment. The Geo Forschungs Zentrum (GFZ) Potsdam is the Principal Investigator of EnMAP. DLR OS and KT were driving the technology of new detectors and the FPA design for this project, new manufacturing accuracy and on-chip processing capability in order to keep pace with the ambitious scientific and user requirements. In combination with the engineering research, the current generations of space borne sensor systems are focusing on VIS/NIR high spectral resolution to meet the requirements on earth and planetary observation systems. The combination of large swath and high spectral resolution with intelligent synchronization control, fast-readout ADC chains and new focal-plane concepts open the door to new remote-sensing and smart deep space instruments. The paper gives an overview over the detector verification program at DLR on FPA level, new control possibilities for sCMOS detectors in global shutter mode and key parameters like PRNU, DSNU, MTF, SNR, Linearity, Spectral Response, Quantum Efficiency, Flatness and Radiation Tolerance will be discussed in detail.

  15. X-ray characterization of CMOS imaging detector with high resolution for fluoroscopic imaging application

    Science.gov (United States)

    Cha, Bo Kyung; Kim, Cho Rong; Jeon, Seongchae; Kim, Ryun Kyung; Seo, Chang-Woo; Yang, Keedong; Heo, Duchang; Lee, Tae-Bum; Shin, Min-Seok; Kim, Jong-Boo; Kwon, Oh-Kyung

    2013-12-01

    This paper introduces complementary metal-oxide semiconductor (CMOS) active pixel sensor (APS)-based X-ray imaging detectors with high spatial resolution for medical imaging application. In this study, our proposed X-ray CMOS imaging sensor has been fabricated by using a 0.35 μm 1 Poly 4 Metal CMOS process. The pixel size is 100 μm×100 μm and the pixel array format is 24×96 pixels, which provide a field-of-view (FOV) of 9.6 mm×2.4 mm. The 14.3-bit extend counting analog-to digital converter (ADC) with built-in binning mode was used to reduce the area and simultaneously improve the image resolution. Both thallium-doped CsI (CsI:Tl) and Gd2O2S:Tb scintillator screens were used as converters for incident X-rays to visible light photons. The optical property and X-ray imaging characterization such as X-ray to light response as a function of incident X-ray exposure dose, spatial resolution and X-ray images of objects were measured under different X-ray energy conditions. The measured results suggest that our developed CMOS-based X-ray imaging detector has the potential for fluoroscopic imaging and cone-beam computed tomography (CBCT) imaging applications.

  16. Silicon detector for a Compton Camera in Nuclear Medical Imaging

    CERN Document Server

    Meier, D; Jalocha, P; Sowicki, B; Kowal, M; Dulinski, W; Maehlum, G; Nygård, E; Yoshioka, K; Fuster, J A; Lacasta, C; Mikuz, M; Roe, S; Weilhammer, Peter; Hua, C H; Park, S J; Wilderman, S J; Zhang, L; Clinthorne, N H; Rogers, W L

    2001-01-01

    Electronically collimated gamma ca\\-me\\-ras based on Com\\-pton scattering in silicon pad sensors may improve imaging in nuclear medicine and bio-medical research. The work described here concentrates on the silicon pad detector developed for a prototype Compton camera. The silicon pad sensors are read out using low noise VLSI CMOS chips and novel fast triggering chips. Depending on the application a light weight and dense packaging of sensors and its readout electronics on a hybrid is required. We describe the silicon pad sensor and their readout with the newly designed hybrid. %The silicon detector of a Compton camera %may contain up to $10^5$~analogue channels requiring %a fast and low cost data acquisition system. We also describe a modular and low-cost data acquisition system (CCDAQ) based on a digital signal processor which is interfaced to the EPP port of personal computers. Using the CCDAQ and the hybrids energy spectra of gamma-ray photons from technetium ($^{\\rm 99m}_{43}$Tc) and americium ($^{241}_{...

  17. Development of a Time-resolved Neutron Imaging Detector Based on the {\\mu}PIC Micro-Pixel Chamber

    CERN Document Server

    Parker, Joseph D; Hattori, Kaori; Iwaki, Satoru; Kabuki, Shigeto; Kishimoto, Yuji; Kubo, Hidetoshi; Kurosawa, Shunsuke; Matsuoka, Yoshihiro; Miuchi, Kentaro; Mizumoto, Tetsuya; Nishimura, Hironobu; Oku, Takayuki; Sawano, Tatsuya; Shinohara, Takenao; Suzuki, Jun-ichi; Takada, Atsushi; Tanimori, Toru; Ueno, Kazuki; Ikeno, Masahiro; Tanaka, Manobu; Uchida, Tomohisa

    2013-01-01

    We have developed a prototype time-resolved neutron imaging detector employing a micro-pattern gaseous detector known as the micro-pixel chamber ({\\mu}PIC) coupled with a field-programmable-gate-array-based data acquisition system. Our detector system combines 100{\\mu}m-level spatial and sub-{\\mu}s time resolutions with a low gamma sensitivity of less than 10^-12 and high data rates, making it well suited for applications in neutron radiography at high-intensity, pulsed neutron sources. In the present paper, we introduce the detector system and present several test measurements performed at NOBORU (BL10), J-PARC to demonstrate the capabilities of our prototype. We also discuss future improvements to the spatial resolution and rate performance.

  18. An automatic attenuator device for x-ray detectors at high counting rate

    Science.gov (United States)

    Alvarez, J.; Paiser, E.; Capitan, M. J.

    2002-07-01

    In this article we describe an attenuator device for reducing/controlling the pulse detector counting losses at a high counting rate. The electronics are based on a direct measure of the detector dead time from the analog output signal at the end of the detection chain. Taking into account this parameter the attenuator device decides to reduce/enhance the number of photons that arrive at the detector by inserting/extracting the necessary number of attenuation foils in the x-ray beam path. In that way the number of events in the incoming signal are reduced and the "apparent dynamic range" of the detector is increased.

  19. Room temperature single-photon detectors for high bit rate quantum key distribution

    Energy Technology Data Exchange (ETDEWEB)

    Comandar, L. C.; Patel, K. A. [Toshiba Research Europe Ltd., 208 Cambridge Science Park, Milton Road, Cambridge CB4 0GZ (United Kingdom); Engineering Department, Cambridge University, 9 J J Thomson Ave., Cambridge CB3 0FA (United Kingdom); Fröhlich, B., E-mail: bernd.frohlich@crl.toshiba.co.uk; Lucamarini, M.; Sharpe, A. W.; Dynes, J. F.; Yuan, Z. L.; Shields, A. J. [Toshiba Research Europe Ltd., 208 Cambridge Science Park, Milton Road, Cambridge CB4 0GZ (United Kingdom); Penty, R. V. [Engineering Department, Cambridge University, 9 J J Thomson Ave., Cambridge CB3 0FA (United Kingdom)

    2014-01-13

    We report room temperature operation of telecom wavelength single-photon detectors for high bit rate quantum key distribution (QKD). Room temperature operation is achieved using InGaAs avalanche photodiodes integrated with electronics based on the self-differencing technique that increases avalanche discrimination sensitivity. Despite using room temperature detectors, we demonstrate QKD with record secure bit rates over a range of fiber lengths (e.g., 1.26 Mbit/s over 50 km). Furthermore, our results indicate that operating the detectors at room temperature increases the secure bit rate for short distances.

  20. The Ring Imaging Cherenkov detector (RICH) of the AMS experiment

    CERN Document Server

    Barão, F; Alcaraz, J; Arruda, L; Barrau, A; Barreira, G; Belmont, E; Berdugo, J; Brinet, M; Buénerd, M; Casadei, D; Casaus, J; Cortina, E; Delgado, C; Díaz, C; Derome, L; Eraud, L; Garcia-Lopez, R J; Gallin-Martel, L; Giovacchini, F; Gonçalves, P; Lanciotti, E; Laurenti, G; Malinine, A; Maña, C; Marin, J; Martínez, G; Menchaca-Rocha, A; Molla, M; Palomares, C; Panniello, M; Pereira, R; Pimenta, M; Protasov, K; Sánchez, E; Seo, E S; Sevilla, N; Torrento, A; Vargas-Trevino, M; Veziant, O

    2006-01-01

    The Alpha Magnetic Spectrometer (AMS) experiment to be installed on the International Space Station (ISS) will be equipped with a proximity focusing Ring Imaging Cherenkov (RICH) detector for measuring the electric charge and velocity of the charged cosmic particles. A RICH prototype consisting of 96 photomultiplier units, including a piece of the conical reflector, was built and its performance evaluated with ion beam data. Preliminary results of the in-beam tests performed with ion fragments resulting from collisions of a 158 GeV/c/nuc primary beam of Indium ions (CERN SPS) on a Pb target are reported. The collected data included tests to the final front-end electronics and to different aerogel radiators. Cherenkov rings for a large range of charged nuclei and with reflected photons were observed. The data analysis confirms the design goals. Charge separation up to Fe and velocity resolution of the order of 0.1% for singly charged particles are obtained.

  1. CMOS detector arrays in a virtual 10-kilopixel camera for coherent terahertz real-time imaging.

    Science.gov (United States)

    Boppel, Sebastian; Lisauskas, Alvydas; Max, Alexander; Krozer, Viktor; Roskos, Hartmut G

    2012-02-15

    We demonstrate the principle applicability of antenna-coupled complementary metal oxide semiconductor (CMOS) field-effect transistor arrays as cameras for real-time coherent imaging at 591.4 GHz. By scanning a few detectors across the image plane, we synthesize a focal-plane array of 100×100 pixels with an active area of 20×20 mm2, which is applied to imaging in transmission and reflection geometries. Individual detector pixels exhibit a voltage conversion loss of 24 dB and a noise figure of 41 dB for 16 μW of the local oscillator (LO) drive. For object illumination, we use a radio-frequency (RF) source with 432 μW at 590 GHz. Coherent detection is realized by quasioptical superposition of the image and the LO beam with 247 μW. At an effective frame rate of 17 Hz, we achieve a maximum dynamic range of 30 dB in the center of the image and more than 20 dB within a disk of 18 mm diameter. The system has been used for surface reconstruction resolving a height difference in the μm range.

  2. An automatic coastline detector for use with SAR images

    Energy Technology Data Exchange (ETDEWEB)

    Erteza, Ireena A.

    1998-09-01

    SAR imagery for coastline detection has many potential advantages over conventional optical stereoscopic techniques. For example, SAR does not have restrictions on being collected during daylight or when there is no cloud cover. In addition, the techniques for coastline detection witth SAR images can be automated. In this paper, we present the algorithmic development of an automatic coastline detector for use with SAR imagery. Three main algorithms comprise the automatic coastline detection algorithm, The first algorithm considers the image pre-processing steps that must occur on the original image in order to accentuate the land/water boundary. The second algorithm automatically follows along the accentuated land/water boundary and produces a single-pixel-wide coastline. The third algorithm identifies islands and marks them. This report describes in detail the development of these three algorithms. Examples of imagery are used throughout the paper to illustrate the various steps in algorithms. Actual code is included in appendices. The algorithms presented are preliminary versions that can be applied to automatic coastline detection in SAR imagery. There are many variations and additions to the algorithms that can be made to improve robustness and automation, as required by a particular application.

  3. A novel fast-neutron detector concept for energy-selective imaging and imaging spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cortesi, M.; Prasser, H.-M. [Nuclear Energy and Safety Research Department, Paul Scherrer Institut, Villigen PSI 5234 (Switzerland); Mechanical Engineering Department, Swiss Federal Institute of Technology, Zurich 8092 (Switzerland); Dangendorf, V. [Ion and Neutron Radiation Department, Physikalisch-Technische Bundesanstalt, Braunschweig 38116 (Germany); Zboray, R. [Mechanical Engineering Department, Swiss Federal Institute of Technology, Zurich 8092 (Switzerland)

    2014-07-15

    We present and discuss the operational principle of a new fast-neutron detector concept suitable for either energy-selective imaging or for imaging spectroscopy. The detector is comprised of a series of energy-selective stacks of converter foils immersed in a noble-gas based mixture, coupled to a position-sensitive charge readout. Each foil in the various stacks is made of two layers of different thicknesses, fastened together: a hydrogen-rich (plastic) layer for neutron-to-proton conversion, and a hydrogen-free coating to selectively stop/absorb the recoil protons below a certain energy cut-off. The neutron-induced recoil protons, that escape the converter foils, release ionization electrons in the gas gaps between consecutive foils. The electrons are then drifted towards and localized by a position-sensitive charge amplification and readout stage. Comparison of the images detected by stacks with different energy cut-offs allows energy-selective imaging. Neutron energy spectrometry is realized by analyzing the responses of a sufficient large number of stacks of different energy response and unfolding techniques. In this paper, we present the results of computer simulation studies and discuss the expected performance of the new detector concept. Potential applications in various fields are also briefly discussed, in particularly, the application of energy-selective fast-neutron imaging for nuclear safeguards application, with the aim of determining the plutonium content in Mixed Oxide (MOX) fuels.

  4. Scalable multiplexed detector system for high-rate telecom-band single-photon detection.

    Science.gov (United States)

    Brida, G; Degiovanni, I P; Piacentini, F; Schettini, V; Polyakov, S V; Migdall, A

    2009-11-01

    We present an actively multiplexed photon-counting detection system at telecom wavelengths that overcomes the difficulties of photon-counting at high rates. We find that for gated detectors, the heretofore unconsidered deadtime associated with the detector gate is a critical parameter, that limits the overall scalability of the scheme to just a few detectors. We propose and implement a new scheme that overcomes this problem and restores full scalability that allows an order of magnitude improvement with systems with as few as 4 detectors. When using just two multiplexed detectors, our experimental results show a 5x improvement over a single detector and a greater than 2x improvement over multiplexed schemes that do not consider gate deadtime.

  5. Signal-Conditioning Block of a 1 × 200 CMOS Detector Array for a Terahertz Real-Time Imaging System

    Directory of Open Access Journals (Sweden)

    Jong-Ryul Yang

    2016-03-01

    Full Text Available A signal conditioning block of a 1 × 200 Complementary Metal-Oxide-Semiconductor (CMOS detector array is proposed to be employed with a real-time 0.2 THz imaging system for inspecting large areas. The plasmonic CMOS detector array whose pixel size including an integrated antenna is comparable to the wavelength of the THz wave for the imaging system, inevitably carries wide pixel-to-pixel variation. To make the variant outputs from the array uniform, the proposed signal conditioning block calibrates the responsivity of each pixel by controlling the gate bias of each detector and the voltage gain of the lock-in amplifiers in the block. The gate bias of each detector is modulated to 1 MHz to improve the signal-to-noise ratio of the imaging system via the electrical modulation by the conditioning block. In addition, direct current (DC offsets of the detectors in the array are cancelled by initializing the output voltage level from the block. Real-time imaging using the proposed signal conditioning block is demonstrated by obtaining images at the rate of 19.2 frame-per-sec of an object moving on the conveyor belt with a scan width of 20 cm and a scan speed of 25 cm/s.

  6. Signal-Conditioning Block of a 1 × 200 CMOS Detector Array for a Terahertz Real-Time Imaging System.

    Science.gov (United States)

    Yang, Jong-Ryul; Lee, Woo-Jae; Han, Seong-Tae

    2016-03-02

    A signal conditioning block of a 1 × 200 Complementary Metal-Oxide-Semiconductor (CMOS) detector array is proposed to be employed with a real-time 0.2 THz imaging system for inspecting large areas. The plasmonic CMOS detector array whose pixel size including an integrated antenna is comparable to the wavelength of the THz wave for the imaging system, inevitably carries wide pixel-to-pixel variation. To make the variant outputs from the array uniform, the proposed signal conditioning block calibrates the responsivity of each pixel by controlling the gate bias of each detector and the voltage gain of the lock-in amplifiers in the block. The gate bias of each detector is modulated to 1 MHz to improve the signal-to-noise ratio of the imaging system via the electrical modulation by the conditioning block. In addition, direct current (DC) offsets of the detectors in the array are cancelled by initializing the output voltage level from the block. Real-time imaging using the proposed signal conditioning block is demonstrated by obtaining images at the rate of 19.2 frame-per-sec of an object moving on the conveyor belt with a scan width of 20 cm and a scan speed of 25 cm/s.

  7. Sci-Fri AM: Imaging - 02: High resolution detectors for PET mammography.

    Science.gov (United States)

    Cuddy, S G; Rowlands, J A

    2012-07-01

    With high specificity for malignant breast lesions, dedicated-breast molecular imaging systems such as positron emission mammography (PEM) have potential to improve the sensitivity of cancer in women with radio-dense breasts and to reduce the false-positive rate of breast screening when used as a diagnostic adjunct. For high signal-to-noise ratio and to minimize the patient dose, scintillation detectors in a PEM system must have high annihilation photon detection efficiency. This efficiency can be increased by accepting annihilation photons from wider incident angles and by using depth-of-interaction (DOI) measurement within a scintillation crystal to minimize parallax blurring. We have developed a dual-ended readout block (DERB) detector that uses asymmetry of signals from photodetectors on either end of a scintillation array to measure DOI and uses Anger Logic with light sharing to identify interacting crystal elements while minimizing the number of photodetectors required. A prototype DERB detector was constructed from two arrays of silicon photomultipliers (SiPM), two glass optical diffusers, and an array of LYSO scintillation crystals. Assembled, each of the 2 × 2 SiPM arrays detect photons that are dispersed via the optical light diffusers originating from either end of 3 × 3 scintillation crystal elements. We evaluated the ability of the detector to identify the crystal index, resolve DOI, and discriminate energy. The DERB detector was able to clearly identify interacting crystal elements, to measure DOI with ̃5mm resolution in 2mm × 2mm × 20mm crystals, and to achieve an average energy resolution of ̃20%. The DERB detector characteristics suggest that it can be used to reduce the parallax effect in PEM systems without increasing the number of required photodetectors. Further investigation is warranted to improve performance with high optical photon detection efficiency photodetectors. © 2012 American Association of Physicists in Medicine.

  8. Electronic noise in CT detectors: Impact on image noise and artifacts.

    Science.gov (United States)

    Duan, Xinhui; Wang, Jia; Leng, Shuai; Schmidt, Bernhard; Allmendinger, Thomas; Grant, Katharine; Flohr, Thomas; McCollough, Cynthia H

    2013-10-01

    The objective of our study was to evaluate in phantoms the differences in CT image noise and artifact level between two types of commercial CT detectors: one with distributed electronics (conventional) and one with integrated electronics intended to decrease system electronic noise. Cylindric water phantoms of 20, 30, and 40 cm in diameter were scanned using two CT scanners, one equipped with integrated detector electronics and one with distributed detector electronics. All other scanning parameters were identical. Scans were acquired at four tube potentials and 10 tube currents. Semianthropomorphic phantoms were scanned to mimic the shoulder and abdominal regions. Images of two patients were also selected to show the clinical values of the integrated detector. Reduction of image noise with the integrated detector depended on phantom size, tube potential, and tube current. Scans that had low detected signal had the greatest reductions in noise, up to 40% for a 30-cm phantom scanned using 80 kV. This noise reduction translated into up to 50% in dose reduction to achieve equivalent image noise. Streak artifacts through regions of high attenuation were reduced by up to 45% on scans obtained using the integrated detector. Patient images also showed superior image quality for the integrated detector. For the same applied radiation level, the use of integrated electronics in a CT detector showed a substantially reduced level of electronic noise, resulting in reductions in image noise and artifacts, compared with detectors having distributed electronics.

  9. Feasibility Study of an Active Sandwich Detector for duel-energy imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dongwoon; Han, Jongchul; Kim, Hokyung [Pusan National Univ., Busan, (Korea, Republic of)

    2013-10-15

    In this study, we investigate a feasibility of sandwich detector based on flat-panel detectors for dual-energy x-ray imaging, particularly for industry application such as a foreign substance detection in noodles. Dual-energy (DE) imaging can remove overlapping background structures that obscure the detection and characterization of target object in radiographs. Although the theoretical framework describing DE imaging had been initialized in the late of 1970s, its renewed interest has been in the spotlight since large area flat-panel detectors capable of real-time imaging with high detective quantum efficiency had been commercially available. DE x-ray imaging based on the fast kVp-switching technique (also known as 'double shot or double-exposure' DE imaging), which acquires low- and high-energy projections in successive exposures, is therefore now available in clinic. Figure 1(a), (b) and (c) show preparations of 'single shot or single-exposure' DE imaging detector, which acquires low- and high-energy projections simultaneously from two detectors arranged in upper and lower layers. Since two detectors are doubly layered, we named it 'the sandwich detector'. While sandwich-detector configurations based on 'passive' film-screen combinations or storage phosphors were often reported, there has not been sufficient attention paid to the use of 'active' solid-state detectors.

  10. Count rate performance of a silicon-strip detector for photon-counting spectral CT

    Science.gov (United States)

    Liu, X.; Grönberg, F.; Sjölin, M.; Karlsson, S.; Danielsson, M.

    2016-08-01

    A silicon-strip detector is developed for spectral computed tomography. The detector operates in photon-counting mode and allows pulse-height discrimination with 8 adjustable energy bins. In this work, we evaluate the count-rate performance of the detector in a clinical CT environment. The output counts of the detector are measured for x-ray tube currents up to 500 mA at 120 kV tube voltage, which produces a maximum photon flux of 485 Mphotons/s/mm2 for the unattenuated beam. The corresponding maximum count-rate loss of the detector is around 30% and there are no saturation effects. A near linear relationship between the input and output count rates can be observed up to 90 Mcps/mm2, at which point only 3% of the input counts are lost. This means that the loss in the diagnostically relevant count-rate region is negligible. A semi-nonparalyzable dead-time model is used to describe the count-rate performance of the detector, which shows a good agreement with the measured data. The nonparalyzable dead time τn for 150 evaluated detector elements is estimated to be 20.2±5.2 ns.

  11. Optimization of high count rate event counting detector with Microchannel Plates and quad Timepix readout

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu; Vallerga, J.V.; McPhate, J.B.; Siegmund, O.H.W.

    2015-07-01

    Many high resolution event counting devices process one event at a time and cannot register simultaneous events. In this article a frame-based readout event counting detector consisting of a pair of Microchannel Plates and a quad Timepix readout is described. More than 10{sup 4} simultaneous events can be detected with a spatial resolution of ~55 µm, while >10{sup 3} simultaneous events can be detected with <10 µm spatial resolution when event centroiding is implemented. The fast readout electronics is capable of processing >1200 frames/sec, while the global count rate of the detector can exceed 5×10{sup 8} particles/s when no timing information on every particle is required. For the first generation Timepix readout, the timing resolution is limited by the Timepix clock to 10–20 ns. Optimization of the MCP gain, rear field voltage and Timepix threshold levels are crucial for the device performance and that is the main subject of this article. These devices can be very attractive for applications where the photon/electron/ion/neutron counting with high spatial and temporal resolution is required, such as energy resolved neutron imaging, Time of Flight experiments in lidar applications, experiments on photoelectron spectroscopy and many others.

  12. Proposed helmet PET geometries with add-on detectors for high sensitivity brain imaging

    Science.gov (United States)

    Tashima, Hideaki; Yamaya, Taiga

    2016-10-01

    For dedicated brain PET, we can significantly improve sensitivity for the cerebrum region by arranging detectors in a compact hemisphere. The geometrical sensitivity for the top region of the hemisphere is increased compared with conventional cylindrical PET consisting of the same number of detectors. However, the geometrical sensitivity at the center region of the hemisphere is still low because the bottom edge of the field-of-view is open, the same as for the cylindrical PET. In this paper, we proposed a helmet PET with add-on detectors for high sensitivity brain PET imaging for both center and top regions. The key point is the add-on detectors covering some portion of the spherical surface in addition to the hemisphere. As the location of the add-on detectors, we proposed three choices: a chin detector, ear detectors, and a neck detector. For example, the geometrical sensitivity for the region-of-interest at the center was increased by 200% by adding the chin detector which increased the size by 12% of the size of the hemisphere detector. The other add-on detectors gave almost the same increased sensitivity effect as the chin detector did. Compared with standard whole-body-cylindrical PET, the proposed geometries can achieve 2.6 times higher sensitivity for brain region even with less than 1/4 detectors. In addition, we conducted imaging simulations for geometries with a diameter of 250 mm and with high resolution depth-of-interaction detectors. The simulation results showed that the proposed geometries increased image quality, and all of the add-on detectors were equivalently effective. In conclusion, the proposed geometries have high potential for widespread applications in high-sensitivity, high-resolution, and low-cost brain PET imaging.

  13. Analysis of detector performance in a gigahertz clock rate quantum key distribution system

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Patrick J; Collins, Robert J; Hiskett, Philip A; GarcIa-MartInez, MarIa-Jose; Krichel, Nils J; McCarthy, Aongus; Tanner, Michael G; O' Connor, John A; Natarajan, Chandra M; Hadfield, Robert H; Buller, Gerald S [Scottish Universities Physics Alliance and School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Miki, Shigehito; Sasaki, Masahide; Wang, Zhen; Fujiwara, Mikio [National Institute of Information and Communications Technology (NICT), 4-2-1 Nukui-kitamachi, Koganei, Tokyo 184-8795 (Japan); Rech, Ivan; Ghioni, Massimo; Gulinatti, Angelo [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Townsend, Paul D, E-mail: G.S.Buller@hw.ac.uk [Tyndall National Institute and Department of Physics, University College Cork, Cork (Ireland)

    2011-07-15

    We present a detailed analysis of a gigahertz clock rate environmentally robust phase-encoded quantum key distribution (QKD) system utilizing several different single-photon detectors, including the first implementation of an experimental resonant cavity thin-junction silicon single-photon avalanche diode. The system operates at a wavelength of 850 nm using standard telecommunications optical fibre. A general-purpose theoretical model for the performance of QKD systems is presented with reference to these experimental results before predictions are made about realistic detector developments in this system. We discuss, with reference to the theoretical model, how detector operating parameters can be further optimized to maximize key exchange rates.

  14. A prototype of radiation imaging detector using silicon strip sensors

    Science.gov (United States)

    Ryu, S.; Hyun, H. J.; Kah, D. H.; Kang, H. D.; Kim, H. J.; Kim, Kyeryung; Kim, Y. I.; Park, H.; Son, D. H.

    2008-06-01

    The aim of this work is to evaluate the performance of a strip sensor with a single photon counting data acquisition system based on VA1 readout chips to study the feasibility of a silicon microstrip detector for medical application. The sensor is an AC-coupled single-sided microstrip sensor and the active area of the sensor is 32.0 mm×32.0 mm with a thickness of 380 μm. The sensor has 64 readout strips with a pitch of 500 μm. The sensor was biased at 45 V and the experiment was performed at room temperature. Two silicon strip sensors were mounted perpendicularly one another to get two-dimensional position information with a 5 mm space gap. Two low noise analog ASICs, VA1 chips, were used for signal readout of the strip sensor. The assembly of sensors and readout electronics was housed in an Al light-tight box. A CsI(Tl) scintillation crystal and a 2-in. photomultiplier tube were used to trigger signal events. The data acquisition system was based on a 64 MHz FADC and control softwares for the PC-Linux platform. Imaging tests were performed by using a lead phantom with a 90Sr radioactive source and a 45 MeV proton beam at Korea Institute of Radiological and Medical Science in Seoul, respectively. Results of the S/ N ratio measurement and phantom images are presented.

  15. Simulating the Counting Mechanism of PILATUS2 and PILATUS3 Detectors for Improved Count Rate Corrections

    Science.gov (United States)

    Trueb, P.; Sobott, B. A.; Schnyder, R.; Loeliger, T.; Schneebeli, M.; Kobas, M.; Rassool, R. P.; Peake, D. J.; Broennimann, C.

    2013-03-01

    PILATUS systems are well established as X-ray detectors at most synchrotrons. Their single photon counting capability ensures precise measurements, but introduces a short dead time after each hit, which becomes significant for photon rates above a million per second and pixel. The resulting loss in the number of counted photons can be corrected for by applying corresponding rate correction factors. This article presents a Monte-Carlo simulation, which computes the correction factors taking into account the detector settings as well as the time structure of the X-ray beam at the synchrotron. For the PILATUS2 detector series the simulation shows good agreement with experimentally determined correction factors for various detector settings at different synchrotrons. The application of more accurate rate correction factors will improve the X-ray data quality at high photon fluxes. Furthermore we report on the simulation of the rate correction factors for the new PILATUS3 systems. The successor of the PILATUS2 detector avoids the paralysation of the counter, and allows for measurements up to a rate of ten million photons per second and pixel. For fast detector settings the simulation is capable of reproducing the data within one to two percent at an incoming photon rate of one million per second and pixel.

  16. Solid-state, flat-panel, digital radiography detectors and their physical imaging characteristics.

    Science.gov (United States)

    Cowen, A R; Kengyelics, S M; Davies, A G

    2008-05-01

    Solid-state, digital radiography (DR) detectors, designed specifically for standard projection radiography, emerged just before the turn of the millennium. This new generation of digital image detector comprises a thin layer of x-ray absorptive material combined with an electronic active matrix array fabricated in a thin film of hydrogenated amorphous silicon (a-Si:H). DR detectors can offer both efficient (low-dose) x-ray image acquisition plus on-line readout of the latent image as electronic data. To date, solid-state, flat-panel, DR detectors have come in two principal designs, the indirect-conversion (x-ray scintillator-based) and the direct-conversion (x-ray photoconductor-based) types. This review describes the underlying principles and enabling technologies exploited by these designs of detector, and evaluates their physical imaging characteristics, comparing performance both against each other and computed radiography (CR). In standard projection radiography indirect conversion DR detectors currently offer superior physical image quality and dose efficiency compared with direct conversion DR and modern point-scan CR. These conclusions have been confirmed in the findings of clinical evaluations of DR detectors. Future trends in solid-state DR detector technologies are also briefly considered. Salient innovations include WiFi-enabled, portable DR detectors, improvements in x-ray absorber layers and developments in alternative electronic media to a-Si:H.

  17. Study of the counting rate capability of MRPC detectors built with soda lime glass

    Science.gov (United States)

    Forster, R.; Margoto Rodríguez, O.; Park, W.; Rodríguez Rodríguez, A.; Williams, M. C. S.; Zichichi, A.; Zuyeuski, R.

    2016-09-01

    We report the results of three MRPC detectors built with soda lime glass and tested in the T10 beam line at CERN. The detectors consist of a stack of 280 μm thick glass sheets with 6 gaps of 220 μm . We built two identical MRPCs, except one had the edges of glass treated with resistive paint. A third detector was built with one HV electrode painted as strips. The detectors' efficiency and time resolution were studied at different particle flux in a pulsed beam environment. The results do not show any improvement with the painted edge technique at higher particle flux. We heated the MRPCs up to 40 °C to evaluate the influence of temperature in the rate capability. Results from this warming has indicated an improvement on the rate capability. The dark count rates show a significant dependence with the temperature.

  18. Cherenkov detectors for spatial imaging applications using discrete-energy photons

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Paul B.; Erickson, Anna S., E-mail: erickson@gatech.edu [Georgia Institute of Technology, Nuclear and Radiological Engineering, G.W. Woodruff School of Mechanical Engineering, 770 State St., Atlanta, Georgia 30332 (United States)

    2016-08-14

    Cherenkov detectors can offer a significant advantage in spatial imaging applications when excellent timing response, low noise and cross talk, large area coverage, and the ability to operate in magnetic fields are required. We show that an array of Cherenkov detectors with crude energy resolution coupled with monochromatic photons resulting from a low-energy nuclear reaction can be used to produce a sharp image of material while providing large and inexpensive detector coverage. The analysis of the detector response to relative transmission of photons with various energies allows for reconstruction of material's effective atomic number further aiding in high-Z material identification.

  19. Cherenkov detectors for spatial imaging applications using discrete-energy photons

    Science.gov (United States)

    Rose, Paul B.; Erickson, Anna S.

    2016-08-01

    Cherenkov detectors can offer a significant advantage in spatial imaging applications when excellent timing response, low noise and cross talk, large area coverage, and the ability to operate in magnetic fields are required. We show that an array of Cherenkov detectors with crude energy resolution coupled with monochromatic photons resulting from a low-energy nuclear reaction can be used to produce a sharp image of material while providing large and inexpensive detector coverage. The analysis of the detector response to relative transmission of photons with various energies allows for reconstruction of material's effective atomic number further aiding in high-Z material identification.

  20. Bio-medical X-ray imaging with spectroscopic pixel detectors

    CERN Document Server

    Butler, A P H; Tipples, R; Cook, N; Watts, R; Meyer, J; Bell, A J; Melzer, T R; Butler, P H

    2008-01-01

    The aim of this study is to review the clinical potential of spectroscopic X-ray detectors and to undertake a feasibility study using a novel detector in a clinical hospital setting. Detectors currently in development, such as Medipix-3, will have multiple energy thresholds allowing for routine use of spectroscopic bio-medical imaging. We have coined the term MARS (Medipix All Resolution System) for bio-medical images that provide spatial, temporal, and energy information. The full clinical significance of spectroscopic X-ray imaging is difficult to predict but insights can be gained by examining both image reconstruction artifacts and the current uses of dual-energy techniques. This paper reviews the known uses of energy information in vascular imaging and mammography, clinically important fields. It then presents initial results from using Medipix-2, to image human tissues within a clinical radiology department. Detectors currently in development, such as Medipix-3, will have multiple energy thresholds allo...

  1. High Count Rate Single Photon Counting Detector Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An optical communications receiver requires efficient and high-rate photon-counting capability so that the information from every photon, received at the aperture,...

  2. 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

  3. Development of Ring Imaging Cherenkov Detectors for LHCb

    CERN Document Server

    Bellunato, T; Matteuzzi, C

    2003-01-01

    The work described in this thesis has been carried out in the framework of the development program of the Ring Imaging Cherenkov (RICH) detectors of the LHCb experiment. LHCb will operate at the Large Hadron Collider at CERN, and it will perform a wide range of measurements in the b-hadrons realm. The extensive study of CP violation and rare decays in the b-hadron system are the main goals of the experiment. An introduction to CP violation in hadronic interactions is given in chapter 1. The high b-b bar production cross section at the LHC energy will provide an unprecedented amount of data which will give LHCb a unique opportunity for precision tests on a large set of physics channels as well as a promising discovery potential for sources of CP violation arising from physics beyond the Standard Model. The experiment is designed in such a way to optimally match the kinematic structure of events where a pair of b quarks is produced in the collision between to 7 GeV protons. Chapter 2 is devoted to an overview o...

  4. Method for growing a back surface contact on an imaging detector used in conjunction with back illumination

    Science.gov (United States)

    Blacksberg, Jordana (Inventor); Hoenk, Michael Eugene (Inventor); Nikzad, Shouleh (Inventor)

    2010-01-01

    A method is provided for growing a back surface contact on an imaging detector used in conjunction with back illumination. In operation, an imaging detector is provided. Additionally, a back surface contact (e.g. a delta-doped layer, etc.) is grown on the imaging detector utilizing a process that is performed at a temperature less than 450 degrees Celsius.

  5. A computer-generated image of the LHCb detector

    CERN Multimedia

    Richard Jacobsson

    2004-01-01

    Unlike most of the detectors on the LHC, which use barrel detectors, the LHCb detector will use walls of sub-detectors to study the particles produced in the 14 TeV proton-proton collisions. This arrangement is used as the bottom and anti-bottom quark pairs produced in the collision, whose decays will be studied, travel close to the path of the colliding beams. LHCb will investigate Naure's preference for matter over antimatter through a process known as CP violation.

  6. Performance of an AGATA prototype detector estimated by Compton-imaging techniques

    Energy Technology Data Exchange (ETDEWEB)

    Recchia, F. [INFN Legnaro (Italy)], E-mail: francesco.recchia@pd.infn.it; Bazzacco, D.; Farnea, E.; Venturelli, R. [INFN Padova (Italy); Aydin, S. [INFN Padova (Italy); Aksaray University (Turkey); Suliman, G. [IFIN-HH, Bucharest (Romania); Ur, C.A. [INFN Padova (Italy)

    2009-06-01

    The imaging capabilities of an AGATA detector have been determined experimentally. Fundamental information on the detector performance can be obtained by a back-projection of the events consisting in a Compton scattering and a subsequent photoelectric absorption. The procedure presented will allow to obtain a feedback on the over-all position resolution of tracking detectors with a high energy resolution. Thanks to its simplicity the method will be used to guarantee the maximal operational performance of tracking arrays such as AGATA.

  7. READOUT ELECTRONICS FOR A HIGH-RATE CSC DETECTOR

    Energy Technology Data Exchange (ETDEWEB)

    OCONNOR,P.; GRATCHEV,V.; KANDASAMY,A.; POLYCHRONAKOS,V.; TCHERNIATINE,V.; PARSONS,J.; SIPPACH,W.

    1999-09-25

    A readout system for a high-rate muon Cathode Strip Chamber (CSC) is described. The system, planned for use in the forward region of the ATLAS muon spectrometer, uses two custom CMOS integrated circuits to achieve good position resolution at a flux of up to 2,500 tracks/cm{sup 2}/s.

  8. Ultraviolet radiation detector to obtain the rate of particles at different heights

    Science.gov (United States)

    Ponce, E.; Flores, E.; Conde, R.

    2016-10-01

    The nature and origin of cosmic rays remains one of the greatest puzzles of modern astrophysics after more than 50 years since their first registration. Several ground experiments have reported the rate registered at its height of operation. To continue with the study of cosmic rays, we propose obtain the rate at different heights in the Earth's atmosphere, developing a small and portable ultraviolet radiation detector, consisting of a scintillation plastic, a PMT, and a fast DAQ system. In this work we present the design and construction of the UV detector and the rate recorded in the Sierra Negra Volcano near Puebla, Mexico (4200 m.a.s.l).

  9. Spatial resolution of a {\\mu}PIC-based neutron imaging detector

    CERN Document Server

    Parker, Joseph D; Hattori, Kaori; Iwaki, Satoru; Kabuki, Shigeto; Kishimoto, Yuji; Kubo, Hidetoshi; Kurosawa, Shunsuke; Matsuoka, Yoshihiro; Miuchi, Kentaro; Mizumoto, Tetsuya; Nishimura, Hironobu; Oku, Takayuki; Sawano, Tatsuya; Shinohara, Takenao; Suzuki, Jun-ichi; Takada, Atsushi; Tanimori, Toru; Ueno, Kazuki

    2013-01-01

    We present a detailed study of the spatial resolution of our time-resolved neutron imaging detector utilizing a new neutron position reconstruction method that improves both spatial resolution and event reconstruction efficiency. Our prototype detector system, employing a micro-pattern gaseous detector known as the micro-pixel chamber ({\\mu}PIC) coupled with a field-programmable-gate-array-based data acquisition system, combines 100{\\mu}m-level spatial and sub-{\\mu}s time resolutions with excellent gamma rejection and high data rates, making it well suited for applications in neutron radiography at high-intensity, pulsed neutron sources. From data taken at the Materials and Life Science Experimental Facility within the Japan Proton Accelerator Research Complex (J-PARC), the spatial resolution was found to be approximately Gaussian with a sigma of 103.48 +/- 0.77 {\\mu}m (after correcting for beam divergence). This is a significant improvement over that achievable with our previous reconstruction method (334 +/...

  10. Ring imaging Cherenkov detector of PHENIX experiment at RHIC

    CERN Document Server

    Akiba, Y; Burward-Hoy, J; Chappell, R; Crook, D; Ebisu, K; Emery, M S; Ferriera, J; Frawley, A D; Hamagaki, H; Hara, H; Hayano, R S; Hemmick, T K; Hibino, M; Hutter, R; Kennedy, M; Kikuchi, J; Matsumoto, T; Moscone, C G; Nagasaka, Y; Nishimura, S; Oyama, K; Sakaguchi, T; Salomone, S; Shigaki, K; Tanaka, Y; Walker, J W; Wintenberg, A L; Young, G R

    1999-01-01

    The RICH detector of the PHENIX experiment at RHIC is currently under construction. Its main function is to identity electron tracks in a very high particle density, about 1000 charged particles per unit rapidity, expected in the most violent collisions at RHIC. The design and construction status of the detector and its expected performance are described.

  11. The CLEO-III Ring Imaging Cherenkov Detector

    CERN Document Server

    Mountain, R J; Artuso, M; Ayad, R; Azfar, F; Coan, T E; Efimov, A; Fadeev, V; Kopp, S E; Kubota, Y; Lipeles, E; Majumder, G; Schuh, S; Skwarnicki, T; Smith, A; Staeck, J; Stone, S; Viehhauser, G; Volobuev, I P

    1999-01-01

    The CLEO-III Detector upgrade for charged particle identification is discussed. The RICH design uses solid LiF crystal radiators coupled with multi-wire chamber photon detectors, using TEA as the photosensor, and low-noise Viking readout electronics. Results from our beam test at Fermilab are presented.

  12. Electrostatic design of the barrel CRID (Cherenkov Ring Imaging Detector) and associated measurements

    Energy Technology Data Exchange (ETDEWEB)

    Abe, K.; Hasegawa, K.; Suekane, F.; Yuta, H. (Tohoku Univ., Sendai (Japan). Dept. of Physics); Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.W.G.S.; Muller, D.; Nagamine, T.; Pavel, T.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Toge, N.; Va' Vra, J. Williams, H. (Stanford Linear Accelerator Center, Menlo Park, CA (US

    1990-04-01

    We report on the electrostatic design and related measurements of the barrel Cherenkov Ring Imaging Detector for the Stanford Large Detector experiment at the Stanford Linear Accelerator Center Linear Collider. We include test results of photon feedback in TMAE-laden gas, distortion measurements in the drift boxes and corona measurements. 13 refs., 21 figs.

  13. Electrostatic design of the barrel CRID (Cherenkov Ring Imaging Detector) and associated measurements

    Energy Technology Data Exchange (ETDEWEB)

    Abe, K.; Hasegawa, K.; Suekane, F.; Yuta, H. (Tohoku Univ., Sendai (Japan). Dept. of Physics); Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.W.G.S.; Muller, D.; Nagamine, T.; Pavel, T.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Toge, N.; Va' Vra, J. Williams, H. (Stanford Linear Accelerator Center, Menlo Park, CA (US

    1990-04-01

    We report on the electrostatic design and related measurements of the barrel Cherenkov Ring Imaging Detector for the Stanford Large Detector experiment at the Stanford Linear Accelerator Center Linear Collider. We include test results of photon feedback in TMAE-laden gas, distortion measurements in the drift boxes and corona measurements. 13 refs., 21 figs.

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

    Science.gov (United States)

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

  15. Gamma-gamma coincidence performance of LaBr3:Ce scintillation detectors vs HPGe detectors in high count-rate scenarios.

    Science.gov (United States)

    Drescher, A; Yoho, M; Landsberger, S; Durbin, M; Biegalski, S; Meier, D; Schwantes, J

    2017-04-01

    A radiation detection system consisting of two cerium doped lanthanum bromide (LaBr3:Ce) scintillation detectors in a gamma-gamma coincidence configuration has been used to demonstrate the advantages that coincident detection provides relative to a single detector, and the advantages that LaBr3:Ce detectors provide relative to high purity germanium (HPGe) detectors. Signal to noise ratios of select photopeak pairs for these detectors have been compared to high-purity germanium (HPGe) detectors in both single and coincident detector configurations in order to quantify the performance of each detector configuration. The efficiency and energy resolution of LaBr3:Ce detectors have been determined and compared to HPGe detectors. Coincident gamma-ray pairs from the radionuclides (152)Eu and (133)Ba have been identified in a sample that is dominated by (137)Cs. Gamma-gamma coincidence successfully reduced the Compton continuum from the large (137)Cs peak, revealed several coincident gamma energies characteristic of these nuclides, and improved the signal-to-noise ratio relative to single detector measurements. LaBr3:Ce detectors performed at count rates multiple times higher than can be achieved with HPGe detectors. The standard background spectrum consisting of peaks associated with transitions within the LaBr3:Ce crystal has also been significantly reduced. It is shown that LaBr3:Ce detectors have the unique capability to perform gamma-gamma coincidence measurements in very high count rate scenarios, which can potentially benefit nuclear safeguards in situ measurements of spent nuclear fuel. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Energy-resolved X-ray detectors: the future of diagnostic imaging

    OpenAIRE

    Pacella D

    2015-01-01

    Danilo Pacella ENEA-Frascati, Rome, Italy Abstract: This paper presents recent progress in the field of X-ray detectors, which could play a role in medical imaging in the near future, with special attention to the new generation of complementary metal-oxide semiconductor (C-MOS) imagers, working in photon counting, that opened the way to the energy-resolved X-ray imaging. A brief description of the detectors used so far in medical imaging (photographic films, imaging plates, flat panel detec...

  17. Precise muon drift tube detectors for high background rate conditions

    CERN Document Server

    Engl, Albert; Dünnweber, Wolfgang

    The muon spectrometer of the ATLAS-experiment at the Large H adron Collider consists of drift tube chambers, which provide the precise m easurement of trajec- tories of traversing muons. In order to determine the moment um of the muons with high precision, the measurement of the position of the m uon in a single tube has to be more accurate than σ ≤ 100 m. The large cross section of proton-proton-collisions and th e high luminosity of the accelerator cause relevant background of neutrons and γ s in the muon spectrome- ter. During the next decade a luminosity upgrade [1] to 5 10 34 cm − 2 s − 1 is planned, which will increase the background counting rates consider ably. In this context this work deals with the further development of the existing drift chamber tech- nology to provide the required accuracy of the position meas urement under high background conditions. Two approaches of improving the dri ft tube chambers are described: • In regions of moderate background rates a faster and more lin ear ...

  18. Psychophysical evaluation of the image quality of a dynamic flat-panel digital x-ray image detector using the threshold contrast detail detectability (TCDD) technique

    Science.gov (United States)

    Davies, Andrew G.; Cowen, Arnold R.; Bruijns, Tom J. C.

    1999-05-01

    We are currently in an era of active development of the digital X-ray imaging detectors that will serve the radiological communities in the new millennium. The rigorous comparative physical evaluations of such devices are therefore becoming increasingly important from both the technical and clinical perspectives. The authors have been actively involved in the evaluation of a clinical demonstration version of a flat-panel dynamic digital X-ray image detector (or FDXD). Results of objective physical evaluation of this device have been presented elsewhere at this conference. The imaging performance of FDXD under radiographic exposure conditions have been previously reported, and in this paper a psychophysical evaluation of the FDXD detector operating under continuous fluoroscopic conditions is presented. The evaluation technique employed was the threshold contrast detail detectability (TCDD) technique, which enables image quality to be measured on devices operating in the clinical environment. This approach addresses image quality in the context of both the image acquisition and display processes, and uses human observers to measure performance. The Leeds test objects TO[10] and TO[10+] were used to obtain comparative measurements of performance on the FDXD and two digital spot fluorography (DSF) systems, one utilizing a Plumbicon camera and the other a state of the art CCD camera. Measurements were taken at a range of detector entrance exposure rates, namely 6, 12, 25 and 50 (mu) R/s. In order to facilitate comparisons between the systems, all fluoroscopic image processing such as noise reduction algorithms, were disabled during the experiments. At the highest dose rate FDXD significantly outperformed the DSF comparison systems in the TCDD comparisons. At 25 and 12 (mu) R/s all three-systems performed in an equivalent manner and at the lowest exposure rate FDXD was inferior to the two DSF systems. At standard fluoroscopic exposures, FDXD performed in an equivalent

  19. The use of segmented cathode of a drift tube for designing a track detector with a high rate capability

    CERN Document Server

    Kuchinskiy, N A; Duginov, V N; Zyazyulya, F E; Korenchenko, A S; Kolesnikov, A O; Kravchuk, N P; Movchan, S A; Rudenko, A I; Smirnov, V S; Khomutov, N V; Chekhovsky, V A

    2013-01-01

    Detector rate capability is one of the main parameters for designing a new detector for high energy physics due to permanent rise of the beam luminosity of modern accelerators. One of the widely used detectors for particle track reconstruction is a straw detector based on drift tubes. The rate capability of such detectors is limited by the parameters of readout electronics. The traditional method of increasing detector rate capability is increasing their granularity (a number of readout channels) by reducing the straw diameter and/or by dividing the straw anode wire into two parts (for decreasing the rate per readout channel). A new method of designing straw detectors with a high rate capability is presented and tested. The method is based on dividing the straw cathode into parts and independent readout of each part.

  20. 320排CT冠状动脉成像平均心率对图像质量和辐射剂量的影响%Impact of mean heart rate on image quality and radiation dose in 320-detector coronary artery angiography

    Institute of Scientific and Technical Information of China (English)

    徐健; 狄幸波; 毛德旺; 陈军法; 钟建国; 曾云建; 张玉江

    2011-01-01

    Objective: To evaluate the image quality and radiation dose of coronary computed tomography angiography (CTA) on patients with various heart rate using 320-detector CT scanner. Methods: A total of two hundred and fifty nine patients who were suspected or known with coronary artery disease underwent coronary CTA. These patients were divided in three subgroups: group A (79 cases),with heart rate below 65 beats per minute; group B (120 cases),with heart rate from 65 to 80 beats per mminutejgroup C (60 cases),with heart rate more than 80 beats per minute. All images with best phase were transferred to a workstation for further post-processing, including VR.MIP.MPR and CPR. Image quality was scored based on 4-point Likert scale in a coronary segmental basis. Statistic analysis was made for grade of image quality and radiation dose,and the relationship between the heart rate and radiation dose was analyzed. Results:No significant difference was found for image quality scale and score in group A,group B and group C (χ2=4. 216,P = 0. 121). Nonassessable seg ments were not found in 35 patients with arrhythmias. Positive correlation was shown between heart rate and image quality score (r=0. 177,P = 0. 000). Mean effective dose was (3. 47 + 2. 48)mSv,(L0. 28±4. 25)mSv,(15. 76±6. 09)mSv in group · A,Band C respectively, there was a significant difference (χ2 = 149. 14, P = 0. 000). Positive correlation was found between heart rate and effective dose (r=0. 101 ,P<0. 001). Conclusion:320-detector CT scanner can provide diagnostic image qual ity within relatively wide range of heart rate and be relevantly adaptive to higer heart rate. Radiation dose was reduced espe cially for patients with heart rate below 65 beats per minute.%目的:探讨不同心率条件下320排容积CT冠状动脉血管成像的图像质量和辐射剂量.方法:将259例临床怀疑或确诊的冠状动脉疾病的患者(含35例心律失常患者)分为3组;A组79例,心率≤65次/分;B组120

  1. Applications of multi-spectral imaging: failsafe industrial flame detector

    Science.gov (United States)

    Wing Au, Kwong; Larsen, Christopher; Cole, Barry; Venkatesha, Sharath

    2016-05-01

    Industrial and petrochemical facilities present unique challenges for fire protection and safety. Typical scenarios include detection of an unintended fire in a scene, wherein the scene also includes a flare stack in the background. Maintaining a high level of process and plant safety is a critical concern. In this paper, we present a failsafe industrial flame detector which has significant performance benefits compared to current flame detectors. The design involves use of microbolometer in the MWIR and LWIR spectrum and a dual band filter. This novel flame detector can help industrial facilities to meet their plant safety and critical infrastructure protection requirements while ensuring operational and business readiness at project start-up.

  2. Image-based spectral distortion correction for photon-counting x-ray detectors

    OpenAIRE

    Ding, Huanjun; Molloi, Sabee

    2012-01-01

    Purpose: To investigate the feasibility of using an image-based method to correct for distortions induced by various artifacts in the x-ray spectrum recorded with photon-counting detectors for their application in breast computed tomography (CT).

  3. The Al sub x Ga sub 1 sub - sub x As X-ray imaging detector

    CERN Document Server

    Pozela, K; Dileenas, A; Jasutis, V; Dapkus, L; Jucienee, V

    2001-01-01

    An X-ray imaging detector based on the graded-gap Al sub x Ga sub 1 sub - sub x As structures with the CCD camera as an image read-out tool is investigated. High X-ray - light conversion efficiency and X-ray image spatial resolution better than 20 line/mm are obtained.

  4. Image blur in a flat-panel detector due to Compton scattering at its internal mountings

    Science.gov (United States)

    Bub, A.; Gondrom, S.; Maisl, M.; Uhlmann, N.; Arnold, W.

    2007-05-01

    An image-blurring effect observable in digital x-ray flat-panel pixel detectors, used for x-ray computed tomography or radioscopy, has been studied. Our study indicates that the origin of this blurring effect is the Compton scattered radiation within the entrance window, the mounting of the detector scintillator and other parts of the detector. This effect becomes, in particular, noticeable in the presence of a sharp edge of a metallic component being tested, making the scattering in the detector asymmetric.

  5. Impact of heart rate and variation of heart rhythm on image quality and radiation dose in 320-detector CT coronary angiography%320排CT冠状动脉成像心率(律)对图像质量和辐射剂量的影响

    Institute of Scientific and Technical Information of China (English)

    徐健; 毛德旺; 张玉江; 陈军法; 丁忠祥

    2011-01-01

    目的:探讨不同心率(律)的条件下,320排容积CT冠状动脉血管成像的图像质量和辐射剂量.方法:将259例临床怀疑或确诊冠状动脉疾病的患者分为两组:窦性心律组(S组)220例;心律失常组(N组)39例.其中S组分为:A组79例,心率<65bpm;B组102例,65≤心率<80bpm;C组39例,心率≥80bpm.扫描完成后选用最佳的时相.对冠状动脉进行容积重组(VR)、多平面重组(MPR)、曲面重组(CPR).按照4分法将图像质量分类并统计分析,比较各组冠状动脉血管段的优良率、可评价性;记录各组的辐射剂量,比较辐射剂量的差异.结果:S组与N组之间冠状动脉血管段优良率和可评价性的差异均无统计学意义.所有病例共有9段冠状动脉不可评价.所有病例平均辐射剂量为(9.49±6.54)mSv;S组和N组平均辐射剂量分别为(8.45±5.7)mSv、(15.36±7.79)mSv,两组之间辐射剂量差异具有统计学意义(t=-5.29,P=0.000).窦性心律各组辐射剂量差异具有统计学意义(x2=126.43,P=0.000).结论:320排CT能较好适应心率(律)变化,保证诊断图像质量,对于心率<65bpm以下的窦性心律患者辐射剂量降低显著.%Objective: To evaluate the image quality and radiation dose of heart rate and heart thythm with prospective electrocardiogram (ECG)-triggering using 320-detector CT scanner. Methods: A total of 259 patients suspected or known coronary artery disease, who underwent coronary CT angiography using 320-detector CT scanner were indiVided into sinuthythm goup (S group) and nonsinurhythm group ( N group). S group was divided into subgroup A (79 cases) with heart rate below 65 beats per minute (bpm); subgroup B (102 cases), with heart rate from 65 to 80 bpm; subgroup C (39 cases) with heart rate beyond 80 bpm. Following data acquisition, all images with best phase were transferred to a workstation for further processing by means of VR, MPR, CPR. Based on 4-point scale, image quality was scored and categorized

  6. Energy-resolved X-ray detectors: the future of diagnostic imaging

    Directory of Open Access Journals (Sweden)

    Pacella D

    2015-01-01

    Full Text Available Danilo Pacella ENEA-Frascati, Rome, Italy Abstract: This paper presents recent progress in the field of X-ray detectors, which could play a role in medical imaging in the near future, with special attention to the new generation of complementary metal-oxide semiconductor (C-MOS imagers, working in photon counting, that opened the way to the energy-resolved X-ray imaging. A brief description of the detectors used so far in medical imaging (photographic films, imaging plates, flat panel detectors, together with the most relevant imaging quality parameters, shows differences between, and advantages of these new C-MOS imagers. X-ray energy-resolved imaging is very attractive not only for the increase of contrast but even for the capability of detecting the nature and composition of the material or tissue to be investigated. Since the X-ray absorption coefficients of the different parts or organs of the patient (object are strongly dependent on the X-ray photon energy, this multienergy ("colored" X-ray imaging could increase enormously the probing capabilities. While dual-energy imaging is now a reality in medical practice, multienergy is still in its early stage, but a promising research activity. Based on this new technique of color X-ray imaging, the entire scheme of source–object–detector could be revised in the future, optimizing spectrum and detector to the nature and composition of the target to be investigated. In this view, a transition to a set of monoenergetic X-ray lines, suitably chosen in energy and intensity, could be envisaged, instead of the present continuous spectra. Keywords: X-ray detectors, X-ray medical imaging, C-MOS imagers, dual and multienergy CT

  7. CZT strip detectors for imaging and spectroscopy: Collimated beam and ASIC readout experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kurczynski, P. [Univ. of Maryland, College Park, MD (United States); Krizmanic, J.F.; Parsons, A. [Goddard Space Flight Center, Greenbelt, MD (United States)

    1996-12-31

    We report the status of ongoing investigations into Cadmium Zinc Telluride (CZT) strip detectors for application in hard x-ray astronomy. We have instrumented a nine strip by nine strip region of a two sided strip detector made in our detector fabrication facility. In order to measure the position resolution of our detectors, we have implemented a collimated beam that concentrates radiation to a spot size less than the strip width of our detector. We have also performed charge collection studies as a function of incident photon energy and bias voltage with a single sided, 100{mu}m pitch CZT strip detector wire bonded to an SVX ASIC charge amplifier. The detectors exhibited excellent strip uniformity in terms of photon count rate and spectroscopic information.

  8. 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.

  9. Direct determination of bulk etching rate for LR-115-II solid state nuclear track detectors

    Indian Academy of Sciences (India)

    T A Salama; U Seddik; T M Heggazy; A Ahmed Morsy

    2006-09-01

    The thickness of the removed layer of the LR-115-II solid state nuclear track detector during etching is measured directly with a rather precise instrument. Dependence of bulk etching rate on temperature of the etching solution is investigated. It has been found that the bulk etching rate is 3.2 m/h at 60°C in 2.5 N NaOH of water solution. It is also found that the track density in detectors exposed to soil samples increases linearly with the removed layer.

  10. Study of readout architectures for triggerless high event rate detectors at CLIC

    CERN Document Server

    Kulis, S

    2011-01-01

    In this work possible readout architectures for future detectors at CLIC are discussed. These detectors will need a triggerless readout electronics with amplitude and time reconstruction and they may operate with very high event rates (≥ 1 hits / channel / bunch train of 156 ns). The main subject of this study, both theoretical and experimental, is a readout based on the deconvolution principle. The basic principle, the performance, the advantages and limitations of this technique are discussed. In the case of extremely high event rates (> 4 hits / channel / bunch train) a readout based on a gated integrator and correlated double sampling is proposed.

  11. CMOS Image Sensor with a Built-in Lane Detector.

    Science.gov (United States)

    Hsiao, Pei-Yung; Cheng, Hsien-Chein; Huang, Shih-Shinh; Fu, Li-Chen

    2009-01-01

    This work develops a new current-mode mixed signal Complementary Metal-Oxide-Semiconductor (CMOS) imager, which can capture images and simultaneously produce vehicle lane maps. The adopted lane detection algorithm, which was modified to be compatible with hardware requirements, can achieve a high recognition rate of up to approximately 96% under various weather conditions. Instead of a Personal Computer (PC) based system or embedded platform system equipped with expensive high performance chip of Reduced Instruction Set Computer (RISC) or Digital Signal Processor (DSP), the proposed imager, without extra Analog to Digital Converter (ADC) circuits to transform signals, is a compact, lower cost key-component chip. It is also an innovative component device that can be integrated into intelligent automotive lane departure systems. The chip size is 2,191.4 × 2,389.8 μm, and the package uses 40 pin Dual-In-Package (DIP). The pixel cell size is 18.45 × 21.8 μm and the core size of photodiode is 12.45 × 9.6 μm; the resulting fill factor is 29.7%.

  12. CMOS Image Sensor with a Built-in Lane Detector

    Directory of Open Access Journals (Sweden)

    Li-Chen Fu

    2009-03-01

    Full Text Available This work develops a new current-mode mixed signal Complementary Metal-Oxide-Semiconductor (CMOS imager, which can capture images and simultaneously produce vehicle lane maps. The adopted lane detection algorithm, which was modified to be compatible with hardware requirements, can achieve a high recognition rate of up to approximately 96% under various weather conditions. Instead of a Personal Computer (PC based system or embedded platform system equipped with expensive high performance chip of Reduced Instruction Set Computer (RISC or Digital Signal Processor (DSP, the proposed imager, without extra Analog to Digital Converter (ADC circuits to transform signals, is a compact, lower cost key-component chip. It is also an innovative component device that can be integrated into intelligent automotive lane departure systems. The chip size is 2,191.4 x 2,389.8 mm, and the package uses 40 pin Dual-In-Package (DIP. The pixel cell size is 18.45 x 21.8 mm and the core size of photodiode is 12.45 x 9.6 mm; the resulting fill factor is 29.7%.

  13. Review on the characteristics of radiation detectors for dosimetry and imaging

    Science.gov (United States)

    Seco, Joao; Clasie, Ben; Partridge, Mike

    2014-10-01

    The enormous advances in the understanding of human anatomy, physiology and pathology in recent decades have led to ever-improving methods of disease prevention, diagnosis and treatment. Many of these achievements have been enabled, at least in part, by advances in ionizing radiation detectors. Radiology has been transformed by the implementation of multi-slice CT and digital x-ray imaging systems, with silver halide films now largely obsolete for many applications. Nuclear medicine has benefited from more sensitive, faster and higher-resolution detectors delivering ever-higher SPECT and PET image quality. PET/MR systems have been enabled by the development of gamma ray detectors that can operate in high magnetic fields. These huge advances in imaging have enabled equally impressive steps forward in radiotherapy delivery accuracy, with 4DCT, PET and MRI routinely used in treatment planning and online image guidance provided by cone-beam CT. The challenge of ensuring safe, accurate and precise delivery of highly complex radiation fields has also both driven and benefited from advances in radiation detectors. Detector systems have been developed for the measurement of electron, intensity-modulated and modulated arc x-ray, proton and ion beams, and around brachytherapy sources based on a very wide range of technologies. The types of measurement performed are equally wide, encompassing commissioning and quality assurance, reference dosimetry, in vivo dosimetry and personal and environmental monitoring. In this article, we briefly introduce the general physical characteristics and properties that are commonly used to describe the behaviour and performance of both discrete and imaging detectors. The physical principles of operation of calorimeters; ionization and charge detectors; semiconductor, luminescent, scintillating and chemical detectors; and radiochromic and radiographic films are then reviewed and their principle applications discussed. Finally, a general

  14. Advanced Photon Counting Imaging Detectors with 100ps Timing for Astronomical and Space Sensing Applications

    Science.gov (United States)

    Siegmund, O.; Vallerga, J.; Welsh, B.; Rabin, M.; Bloch, J.

    In recent years EAG has implemented a variety of high-resolution, large format, photon-counting MCP detectors in space instrumentation for satellite FUSE, GALEX, IMAGE, SOHO, HST-COS, rocket, and shuttle payloads. Our scheme of choice has been delay line readouts encoding photon event position centroids, by determination of the difference in arrival time of the event charge at the two ends of a distributed resistive-capacitive (RC) delay line. Our most commonly used delay line configuration is the cross delay line (XDL). In its simplest form the delay-line encoding electronics consists of a fast amplifier for each end of the delay line, followed by time-to-digital converters (TDC's). We have achieved resolutions of advantages over "frame driven" recording devices for some important applications. For example we have built open face and sealed tube cross delay line detectors used for biological fluorescence lifetime imaging, observation of flare stars, orbital satellites and space debris with the GALEX satellite, and time resolved imaging of the Crab Pulsar with a telescope as small as 1m. Although microchannel plate delay line detectors meet many of the imaging and timing demands of various applications, they have limitations. The relatively high gain (107) reduces lifetime and local counting rate, and the fixed delay (10's of ns) makes multiple simultaneous event recording problematic. To overcome these limitations we have begun development of cross strip readout anodes for microchannel plate detectors. The cross strip (XS) anode is a coarse (~0.5 mm) multi-layer metal and ceramic pattern of crossed fingers on an alumina substrate. The charge cloud is matched to the anode period so that it is collected on several neighboring fingers to ensure an accurate event charge centroid can be determined. Each finger of the anode is connected to a low noise charge sensitive amplifier and followed by subsequent A/D conversion of individual strip charge values and a hardware

  15. Therapy imaging: a signal-to-noise analysis of metal plate/film detectors.

    Science.gov (United States)

    Munro, P; Rawlinson, J A; Fenster, A

    1987-01-01

    We have measured the modulation transfer functions [MTF (f)'s] and the noise power spectra [NPS (f)] of therapy x-ray detectors irradiated by 60Co, 6- and 18-MV radiotherapy beams. Using these quantities, we have calculated the noise-equivalent quanta [NEQ (f)] and the detective quantum efficiency [DQE (f)] to quantitate the limitations of therapy detectors. The detectors consisted of film or fluorescent screen-film combinations in contact with copper, lead, or tungsten metal plates. The resolution of the detectors was found to be comparable to fluorescent screen-film combinations used in diagnostic radiology, however, the signal-to-noise ratio [SNR (f)] of the detectors was limited due to film granularity. We conclude that improved images can be obtained by using alternative detector systems which have less noise or film granularity.

  16. Image quality vs. radiation dose for a flat-panel amorphous silicon detector: a phantom study.

    Science.gov (United States)

    Geijer, H; Beckman, K W; Andersson, T; Persliden, J

    2001-01-01

    The aim of this study was to investigate the image quality for a flat-panel amorphous silicon detector at various radiation dose settings and to compare the results with storage phosphor plates and a screen-film system. A CDRAD 2.0 contrast-detail phantom was imaged with a flat-panel detector (Philips Medical Systems, Eindhoven, The Netherlands) at three different dose levels with settings for intravenous urography. The same phantom was imaged with storage phosphor plates at a simulated system speed of 200 and a screen-film system with a system speed of 160. Entrance surface doses were recorded for all images. At each setting, three images were read by four independent observers. The flat-panel detector had equal image quality at less than half the radiation dose compared with storage phosphor plates. The difference was even larger when compared with film with the flat-panel detector having equal image quality at approximately one-fifth the dose. The flat-panel detector has a very favourable combination of image quality vs radiation dose compared with storage phosphor plates and screen film.

  17. Image quality vs radiation dose for a flat-panel amorphous silicon detector: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Geijer, H.; Andersson, T. [Dept. of Radiology, Oerebro Medical Centre Hospital (Sweden); Beckman, K.W.; Persliden, J. [Dept. of Medical Physics, Oerebro Medical Centre Hospital (Sweden)

    2001-09-01

    The aim of this study was to investigate the image quality for a flat-panel amorphous silicon detector at various radiation dose settings and to compare the results with storage phosphor plates and a screen-film system. A CDRAD 2.0 contrast-detail phantom was imaged with a flat-panel detector (Philips Medical Systems, Eindhoven, The Netherlands) at three different dose levels with settings for intravenous urography. The same phantom was imaged with storage phosphor plates at a simulated system speed of 200 and a screen-film system with a system speed of 160. Entrance surface doses were recorded for all images. At each setting, three images were read by four independent observers. The flat-panel detector had equal image quality at less than half the radiation dose compared with storage phosphor plates. The difference was even larger when compared with film with the flat-panel detector having equal image quality at approximately one-fifth the dose. The flat-panel detector has a very favourable combination of image quality vs radiation dose compared with storage phosphor plates and screen film. (orig.)

  18. Neutron diffractometer for bio-crystallography (BIX) with an imaging plate neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, Nobuo [Japan Atomic Energy Research Inst., Ibaraki-ken (Japan)

    1994-12-31

    We have constructed a dedicated diffractometer for neutron crystallography in biology (BIX) on the JRR-3M reactor at JAERI (Japan Atomic Energy Research Institute). The diffraction intensity from a protein crystal is weaker than that from most inorganic materials. In order to overcome the intensity problem, an elastically bent silicon monochromator and a large area detector system were specially designed. A preliminary result of diffraction experiment using BIX has been reported. An imaging plate neutron detector has been developed and a feasibility experiment was carried out on BIX. Results are reported. An imaging plate neutron detector has been developed and a feasibility test was carried out using BIX.

  19. Application of GEM-based detectors in full-field XRF imaging

    Science.gov (United States)

    Dąbrowski, W.; Fiutowski, T.; Frączek, P.; Koperny, S.; Lankosz, M.; Mendys, A.; Mindur, B.; Świentek, K.; Wiącek, P.; Wróbel, P. M.

    2016-12-01

    X-ray fluorescence spectroscopy (XRF) is a commonly used technique for non-destructive elemental analysis of cultural heritage objects. It can be applied to investigations of provenance of historical objects as well as to studies of art techniques. While the XRF analysis can be easily performed locally using standard available equipment there is a growing interest in imaging of spatial distribution of specific elements. Spatial imaging of elemental distrbutions is usually realised by scanning an object with a narrow focused X-ray excitation beam and measuring characteristic fluorescence radiation using a high energy resolution detector, usually a silicon drift detector. Such a technique, called macro-XRF imaging, is suitable for investigation of flat surfaces but it is time consuming because the spatial resolution is basically determined by the spot size of the beam. Another approach is the full-field XRF, which is based on simultaneous irradiation and imaging of large area of an object. The image of the investigated area is projected by a pinhole camera on a position-sensitive and energy dispersive detector. The infinite depth of field of the pinhole camera allows one, in principle, investigation of non-flat surfaces. One of possible detectors to be employed in full-field XRF imaging is a GEM based detector with 2-dimensional readout. In the paper we report on development of an imaging system equipped with a standard 3-stage GEM detector of 10 × 10 cm2 equipped with readout electronics based on dedicated full-custom ASICs and DAQ system. With a demonstrator system we have obtained 2-D spatial resolution of the order of 100 μm and energy resolution at a level of 20% FWHM for 5.9 keV . Limitations of such a detector due to copper fluorescence radiation excited in the copper-clad drift electrode and GEM foils is discussed and performance of the detector using chromium-clad electrodes is reported.

  20. Compressive spectral polarization imaging by a pixelized polarizer and colored patterned detector.

    Science.gov (United States)

    Fu, Chen; Arguello, Henry; Sadler, Brian M; Arce, Gonzalo R

    2015-11-01

    A compressive spectral and polarization imager based on a pixelized polarizer and colored patterned detector is presented. The proposed imager captures several dispersed compressive projections with spectral and polarization coding. Stokes parameter images at several wavelengths are reconstructed directly from 2D projections. Employing a pixelized polarizer and colored patterned detector enables compressive sensing over spatial, spectral, and polarization domains, reducing the total number of measurements. Compressive sensing codes are specially designed to enhance the peak signal-to-noise ratio in the reconstructed images. Experiments validate the architecture and reconstruction algorithms.

  1. Integrated High-Rate Transition Radiation Detector and Tracking Chamber for the LHC

    CERN Multimedia

    2002-01-01

    % RD-6 \\\\ \\\\Over the past five years, RD-6 has developed a transition radiation detector and charged particle tracker for high rate operation at LHC. The detector elements are based on C-fibre reinforced kapton straw tubes of 4~mm diameter filled with a Xenon gas mixture. Detailed measurements with and without magnetic field have been performed in test beams, and in particular have demonstrated the possibility of operating straw tubes at very high rate (up to 20~MHz) with accurate drift-time measurement accuracy. A full-scale engineering prototype containing 10~000 straws is presently under assembly and will be accurately measured with a powerful X-ray tube. Integrated front-end electronics with fast readout have been designed and successfully operated in test beam. \\\\ \\\\Finally extensive simulations performed for ATLAS have shown that such a detector will provide powerful pattern recognition, accurate momentum measurements, efficient level-2 triggering and excellent electron identification, even at the highe...

  2. Recent Developments: The Gamma Ray Imager/Polarimeter for Solar Flares (GRIPS) Imaging and Detector systems

    Science.gov (United States)

    Duncan, Nicole; Shih, A. Y.; Hurford, G. J.; Saint-Hilaire, P.; Bain, H.; Zoglauer, A.; Lin, R. P.; Boggs, S. E.

    2013-07-01

    In two of the best-observed flares of the last cycle, the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) satellite found the centroids of ion and relativistic electron emission to have a significant displacement. This result is surprising; co-spatially accelerated ions and electrons are thought to be transported along the same field lines, implying they would enter the chromosphere together and have similar emission locations. The Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS) balloon instrument will investigate particle transport in solar flares by providing enhanced imaging, spectroscopy and polarimetry of gamma/HXR flare emission (20keV - 10MeV). GRIPS’ key technological improvements over the solar state of the art in HXR/gamma ray energies (RHESSI) include three-dimensional position-sensitive germanium detectors (3D-GeDs) and a single-grid modulating collimator, the multi-pitch rotating modulator (MPRM). The 3D-GeDs allow GRIPS to Compton track energy deposition within the crystal. This capability (1) enables the MPRM design by acting as a second modulation grid, (2) provides significant background rejection and (3) makes solar polarization measurements possible. The MPRM imager provides quasi-continuous resolution from 12.5 - 162 arcsecs with 2x the throughput of a dual grid collimator system like RHESSI. This spatial resolution can resolve the separate footpoints of many flare sizes. In comparison, RHESSI images with a minimum of 35 arcsecs for gamma-rays, making these footpoints resolvable in only the largest flares. Here, we present the intial calibration of GRIPS’ 3D-GED detectors using laboratory radioactive sources. We evaluate charge sharing between adjacent strips, the detection of coincidences and preliminary depth measurements. The detectors have been shown to have a linear response and resolve line emission. The MPRM modulation grid is constructed and we present initial results from calibration. GRIPS is scheduled for a

  3. A fast microchannel plate-scintillator detector for velocity map imaging and imaging mass spectrometry.

    Science.gov (United States)

    Winter, B; King, S J; Brouard, M; Vallance, C

    2014-02-01

    The time resolution achievable using standard position-sensitive ion detectors, consisting of a chevron pair of microchannel plates coupled to a phosphor screen, is primarily limited by the emission lifetime of the phosphor, around 70 ns for the most commonly used P47 phosphor. We demonstrate that poly-para-phenylene laser dyes may be employed extremely effectively as scintillators, exhibiting higher brightness and much shorter decay lifetimes than P47. We provide an extensive characterisation of the properties of such scintillators, with a particular emphasis on applications in velocity-map imaging and microscope-mode imaging mass spectrometry. The most promising of the new scintillators exhibits an electron-to-photon conversion efficiency double that of P47, with an emission lifetime an order of magnitude shorter. The new scintillator screens are vacuum stable and show no signs of signal degradation even over longer periods of operation.

  4. CIX - A Detector for Spectral Enhanced X-ray Imaging by Simultaneous Counting and Integrating

    CERN Document Server

    Krüger, H; Kraft, E; Wermes, N; Fischer, P; Peric, I; Herrmann, C; Overdick, M; Rütten, W

    2008-01-01

    A hybrid pixel detector based on the concept of simultaneous charge integration and photon counting will be presented. The second generation of a counting and integrating X-ray prototype CMOS chip (CIX) has been operated with different direct converting sensor materials (CdZnTe and CdTe) bump bonded to its 8x8 pixel matrix. Photon counting devices give excellent results for low to medium X-ray fluxes but saturate at high rates while charge integration allows the detection of very high fluxes but is limited at low rates by the finite signal to noise ratio. The combination of both signal processing concepts therefore extends the resolvable dynamic range of the X-ray detector. In addition, for a large region of the dynamic range, where counter and integrator operate simultaneously, the mean energy of the detected X-ray spectrum can be calculated. This spectral information can be used to enhance the contrast of the X-ray image. The advantages of the counting and integrating signal processing concept and the perfo...

  5. Characteristic Count Rate Profiles for a Rotating Modulator Gamma-Ray Imager

    CERN Document Server

    Budden, Brent S; Case, Gary L; Cherry, Michael L

    2011-01-01

    Rotating modulation is a technique for indirect imaging in the hard x-ray and soft gamma-ray energy bands, which may offer an advantage over coded aperture imaging at high energies. A rotating modulator (RM) consists of a single mask of co-planar parallel slats typically spaced equidistance apart, suspended above an array of circular non-imaging detectors. The mask rotates, temporally modulating the transmitted image of the object scene. The measured count rate profiles of each detector are folded modulo the mask rotational period, and the object scene is reconstructed using pre-determined characteristic modulation profiles. The use of Monte Carlo simulation to derive the characteristic count rate profiles is accurate but computationally expensive; an analytic approach is preferred for its speed of computation. We present both the standard and a new advanced characteristic formula describing the modulation pattern of the RM; the latter is a more robust description of the instrument response developed as part ...

  6. A digital X-ray imaging system based on silicon strip detectors working in edge-on configuration

    Energy Technology Data Exchange (ETDEWEB)

    Bolanos, L. [CEADEN, Calle 30 502 e/ 5ta y 7ma Avenida, Playa, Ciudad Habana (Cuba); Boscardin, M. [IRST, Fondazione Bruno Kessler, Via Sommarive 18, Povo, 38100 Trento (Italy); Cabal, A.E. [CEADEN, Calle 30 502 e/ 5ta y 7ma Avenida, Playa, Ciudad Habana (Cuba); Diaz, M. [InSTEC, Ave. Salvador Allende esq. Luaces, Quinta de los Molinos, Ciudad Habana (Cuba); Grybos, P.; Maj, P. [Faculty of Electrical Engineering, Automatics, Computer Science and Electronics, Department of Measurement and Instrumentation, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Cracow (Poland); Prino, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Via P. Giuria 1, 10125 Torino (Italy); Ramello, L. [Dipartimento di Scienze e Tecnologie Avanzate, Universita del Piemonte Orientale, Via T. Michel 11, 15100 Alessandria (Italy)], E-mail: luciano.ramello@mfn.unipmn.it; Szczygiel, R. [Faculty of Electrical Engineering, Automatics, Computer Science and Electronics, Department of Measurement and Instrumentation, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Cracow (Poland)

    2009-09-21

    We present the energy resolution and imaging performance of a digital X-ray imaging system based on a 512-strip silicon strip detector (SSD) working in the edge-on configuration. The SSDs tested in the system are 300 {mu}m thick with 1 or 2-cm-long strips and 100 {mu}m pitch. To ensure a very small dead area of the SSD working in edge-on configuration, the detector is cut perpendicular to the strips at a distance of only 20 {mu}m from the end of the strips. The 512-strip silicon detector is read out by eight 64-channel integrated circuits called DEDIX [Grybos et al., IEEE Trans. Nucl. Sci. NS-54 (2007) 1207]. The DEDIX IC operates in a single photon counting mode with two independent amplitude discriminators per channel. The readout electronic channel connected to a detector with effective input capacitance of about 2 pF has an average equivalent noise charge (ENC) of about 163 el. rms and is able to count 1 Mcps of average rate of input pulses. The system consisting of 512 channels has an excellent channel-to-channel uniformity-the effective threshold spread calculated to the charge-sensitive amplifier inputs is 12 el. rms (at one sigma level). With this system a few test images of a phantom have been taken in the 10-30 keV energy range.

  7. 3-D imaging of particle tracks in solid state nuclear track detectors

    Directory of Open Access Journals (Sweden)

    D. Wertheim

    2010-05-01

    Full Text Available It has been suggested that 3 to 5% of total lung cancer deaths in the UK may be associated with elevated radon concentration. Radon gas levels can be assessed using CR-39 plastic detectors which are often assessed by 2-D image analysis of surface images. 3-D analysis has the potential to provide information relating to the angle at which alpha particles impinge on the detector. In this study we used a "LEXT" OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan to image tracks on five CR-39 detectors. We were able to identify several patterns of single and coalescing tracks from 3-D visualisation. Thus this method may provide a means of detailed 3-D analysis of Solid State Nuclear Track Detectors.

  8. 3-D imaging of particle tracks in solid state nuclear track detectors

    Science.gov (United States)

    Wertheim, D.; Gillmore, G.; Brown, L.; Petford, N.

    2010-05-01

    It has been suggested that 3 to 5% of total lung cancer deaths in the UK may be associated with elevated radon concentration. Radon gas levels can be assessed using CR-39 plastic detectors which are often assessed by 2-D image analysis of surface images. 3-D analysis has the potential to provide information relating to the angle at which alpha particles impinge on the detector. In this study we used a "LEXT" OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan) to image tracks on five CR-39 detectors. We were able to identify several patterns of single and coalescing tracks from 3-D visualisation. Thus this method may provide a means of detailed 3-D analysis of Solid State Nuclear Track Detectors.

  9. The Cerenkov ring-imaging detector recent progress and future development

    CERN Document Server

    Ekelöf, T J C; Tocqueville, J; Ypsilantis, Thomas

    1981-01-01

    Results are reported on measurements of Cerenkov ring images using a multistage MWPC with an argon-TEA gas mixture. A specific detector response of N/sub 0/=56 cm/sup -1/ was obtained. It is shown that with some minor modifications to the detector, this value can be raised to N/sub 0/=90 cm/sup -1/. Using an argon-methane-TEA mixture in the MWPC, it is shown that efficient single-photoelectron detection can be achieved with proportional wire amplification without preamplification. A design of a new type of drift chamber (TPC) detector for two-dimensional measurement of the ring image is described. The use of the Cerenkov ring-imaging technique in high- energy physics experimentation is discussed, and in particular a full solid-angle detector for LEP is suggested. (10 refs).

  10. Development and characterisation of a visible light photon counting imaging detector system

    CERN Document Server

    Barnstedt, J

    2002-01-01

    We report on the development of a visible light photon counting imaging detector system. The detector concept is based on standard 25 mm diameter microchannel plate image intensifiers made by Proxitronic in Bensheim (Germany). Modifications applied to these image intensifiers are the use of three microchannel plates instead of two and a high resistance ceramics plate used instead of the standard phosphor output screen. A wedge and strip anode mounted directly behind the high resistance ceramics plate was used as a read out device. This wedge and strip anode picks up the image charge of electron clouds emerging from the microchannel plates. The charge pulses are fed into four charge amplifiers and subsequently into a digital position decoding electronics, achieving a position resolution of up to 1024x1024 pixels. Mounting the anode outside the detector tube is a new approach and has the great advantage of avoiding electrical feedthroughs from the anode so that the standard image intensifier fabrication process...

  11. Vision 20/20: Single photon counting x-ray detectors in medical imaging.

    Science.gov (United States)

    Taguchi, Katsuyuki; Iwanczyk, Jan S

    2013-10-01

    Photon counting detectors (PCDs) with energy discrimination capabilities have been developed for medical x-ray computed tomography (CT) and x-ray (XR) imaging. Using detection mechanisms that are completely different from the current energy integrating detectors and measuring the material information of the object to be imaged, these PCDs have the potential not only to improve the current CT and XR images, such as dose reduction, but also to open revolutionary novel applications such as molecular CT and XR imaging. The performance of PCDs is not flawless, however, and it seems extremely challenging to develop PCDs with close to ideal characteristics. In this paper, the authors offer our vision for the future of PCD-CT and PCD-XR with the review of the current status and the prediction of (1) detector technologies, (2) imaging technologies, (3) system technologies, and (4) potential clinical benefits with PCDs.

  12. Image translational shifts in microchannel plate detectors due to the presence of MCP channel bias

    CERN Document Server

    Tremsin, A S; Siegmund, O H W

    2002-01-01

    A detailed study of possible image displacements in MCP detectors due to the presence of MCP pore bias is presented. We show that fluctuations of the rear accelerating field, characteristic to some MCP detector configurations, result in translational shifts of the entire image, which degrade the detector spatial resolution. It was experimentally observed that a 10% increase in the rear voltage of 400 V for a detector with 13 deg. -biased MCPs and 8.5 mm MCP-to-anode distance results in a 32 mu m shift of the image in the direction opposite to the pore bias. Increasing the voltage to 800 V induced a 200 mu m image displacement. No displacement was observed for a detector with a 0 deg. -biased output MCP. We also present a model for calculation of the charge footprint centroid in MCP detectors based on the output distribution function of the charge cloud. The results of our computer simulation of the image displacements prove to be in a very good agreement with the experimental data, thus providing the basis fo...

  13. Characteristic performance evaluation of a photon counting Si strip detector for low dose spectral breast CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Hyo-Min; Ding, Huanjun; Molloi, Sabee, E-mail: symolloi@uci.edu [Department of Radiological Sciences, University of California, Irvine, California 92697 (United States); Barber, William C.; Iwanczyk, Jan S. [DxRay Inc., Northridge, California 91324 (United States)

    2014-09-15

    Purpose: The possible clinical applications which can be performed using a newly developed detector depend on the detector's characteristic performance in a number of metrics including the dynamic range, resolution, uniformity, and stability. The authors have evaluated a prototype energy resolved fast photon counting x-ray detector based on a silicon (Si) strip sensor used in an edge-on geometry with an application specific integrated circuit to record the number of x-rays and their energies at high flux and fast frame rates. The investigated detector was integrated with a dedicated breast spectral computed tomography (CT) system to make use of the detector's high spatial and energy resolution and low noise performance under conditions suitable for clinical breast imaging. The aim of this article is to investigate the intrinsic characteristics of the detector, in terms of maximum output count rate, spatial and energy resolution, and noise performance of the imaging system. Methods: The maximum output count rate was obtained with a 50 W x-ray tube with a maximum continuous output of 50 kVp at 1.0 mA. A{sup 109}Cd source, with a characteristic x-ray peak at 22 keV from Ag, was used to measure the energy resolution of the detector. The axial plane modulation transfer function (MTF) was measured using a 67 μm diameter tungsten wire. The two-dimensional (2D) noise power spectrum (NPS) was measured using flat field images and noise equivalent quanta (NEQ) were calculated using the MTF and NPS results. The image quality parameters were studied as a function of various radiation doses and reconstruction filters. The one-dimensional (1D) NPS was used to investigate the effect of electronic noise elimination by varying the minimum energy threshold. Results: A maximum output count rate of 100 million counts per second per square millimeter (cps/mm{sup 2}) has been obtained (1 million cps per 100 × 100 μm pixel). The electrical noise floor was less than 4 keV. The

  14. High-Rate Fast-Time GRPC for the high eta CMS muon detectors

    CERN Document Server

    Mirabito, Laurent

    2016-01-01

    CMS detector. In their single-gap version we will show that they can stand rates of few ${\\rm kHz/cm}^2$. We also demonstrate that using multi-gap glass RPC, a time resolution of about 60 ps is achieved.

  15. Improved count rate corrections for highest data quality with PILATUS detectors.

    Science.gov (United States)

    Trueb, P; Sobott, B A; Schnyder, R; Loeliger, T; Schneebeli, M; Kobas, M; Rassool, R P; Peake, D J; Broennimann, C

    2012-05-01

    The PILATUS detector system is widely used for X-ray experiments at third-generation synchrotrons. It is based on a hybrid technology combining a pixelated silicon sensor with a CMOS readout chip. Its single-photon-counting capability ensures precise and noise-free measurements. The counting mechanism introduces a short dead-time after each hit, which becomes significant for rates above 10(6) photons s(-1) pixel(-1). The resulting loss in the number of counted photons is corrected for by applying corresponding rate correction factors. This article presents the results of a Monte Carlo simulation which computes the correction factors taking into account the detector settings as well as the time structure of the X-ray beam at the synchrotron. The results of the simulation show good agreement with experimentally determined correction factors for various detector settings at different synchrotrons. The application of accurate rate correction factors improves the X-ray data quality acquired at high photon fluxes. Furthermore, it is shown that the use of fast detector settings in combination with an optimized time structure of the X-ray beam allows for measurements up to rates of 10(7) photons s(-1) pixel(-1).

  16. High-Rate Fast-Time GRPC for the high eta CMS muon detectors

    CERN Document Server

    Mirabito, Laurent

    2016-01-01

    CMS detector. In their single-gap version we will show that they can stand rates of few ${\\rm kHz/cm}^2$. We also demonstrate that using multi-gap glass RPC, a time resolution of about 60 ps is achieved.

  17. Effects of frame rate and image resolution on pulse rate measured using multiple camera imaging photoplethysmography

    Science.gov (United States)

    Blackford, Ethan B.; Estepp, Justin R.

    2015-03-01

    Non-contact, imaging photoplethysmography uses cameras to facilitate measurements including pulse rate, pulse rate variability, respiration rate, and blood perfusion by measuring characteristic changes in light absorption at the skin's surface resulting from changes in blood volume in the superficial microvasculature. Several factors may affect the accuracy of the physiological measurement including imager frame rate, resolution, compression, lighting conditions, image background, participant skin tone, and participant motion. Before this method can gain wider use outside basic research settings, its constraints and capabilities must be well understood. Recently, we presented a novel approach utilizing a synchronized, nine-camera, semicircular array backed by measurement of an electrocardiogram and fingertip reflectance photoplethysmogram. Twenty-five individuals participated in six, five-minute, controlled head motion artifact trials in front of a black and dynamic color backdrop. Increasing the input channel space for blind source separation using the camera array was effective in mitigating error from head motion artifact. Herein we present the effects of lower frame rates at 60 and 30 (reduced from 120) frames per second and reduced image resolution at 329x246 pixels (one-quarter of the original 658x492 pixel resolution) using bilinear and zero-order downsampling. This is the first time these factors have been examined for a multiple imager array and align well with previous findings utilizing a single imager. Examining windowed pulse rates, there is little observable difference in mean absolute error or error distributions resulting from reduced frame rates or image resolution, thus lowering requirements for systems measuring pulse rate over sufficient length time windows.

  18. Multi-detector CT imaging in the postoperative orthopedic patient with metal hardware.

    Science.gov (United States)

    Vande Berg, Bruno; Malghem, Jacques; Maldague, Baudouin; Lecouvet, Frederic

    2006-12-01

    Multi-detector CT imaging (MDCT) becomes routine imaging modality in the assessment of the postoperative orthopedic patients with metallic instrumentation that degrades image quality at MR imaging. This article reviews the physical basis and CT appearance of such metal-related artifacts. It also addresses the clinical value of MDCT in postoperative orthopedic patients with emphasis on fracture healing, spinal fusion or arthrodesis, and joint replacement. MDCT imaging shows limitations in the assessment of the bone marrow cavity and of the soft tissues for which MR imaging remains the imaging modality of choice despite metal-related anatomic distortions and signal alteration.

  19. The Development of the Detector and Imaging Systems of the Masco Telescope

    Science.gov (United States)

    Damico, Flavio

    1997-08-01

    In this thesis the detector and imaging systems of the MASCO telescope are described. MASCO is a gamma-ray imaging telescope with both high angular resolution and sensitivity. Conceived to be able to individually study sources in crowded fields, MASCO is an ideal mission to map sky regions like the Galactic Center. A revision of recent observational results obtained with imaging telescopes of this particular region is presented. Also presented is the sensitivity of the telescope for pulsed gamma-ray sources, taking GX 1+4 as an example. MASCO employs the coded-aperture imaging technique, and will be the first telescope to use a new type of mask patterns, the modified uniformly redundant arrays (MURAs). The coded-aperture imaging technique is reviewed and interesting properties of the MURAs discussed. This work gives two original contributions for MURA based coded mask telescopes: an empirical rule that says which MURA pattern is convenient to build a mask when we want to make observations with the mask-antimask method and the definition of the rotation center of a MURA pattern. MASCO uses a large number of scintillation detectors. The main detector of the experiment is a 41 cm diameter and 5 cm thick inorganic NaI(Tl) scintillation detector in an Anger Camera configuration, with approximately 10% energy resolution in 662 keV. Organic scintillation detectors are used to minimize the telescope background. and large volume scintillation detectors were built for the first time in Brazil. MASCO uses 12 of these scintillation detectors and the fabrication process are discussed together with tests for 2 different types of these detectors. MASCO shall have an angular resolution of 14 min in a 14 deg field-of-view and 20 micro-s of temporal resolution. A simulated image of the Galactic Center region in the 50-150 keV energy band is presented in order to show the imaging capabilities of the telescope. Preliminary tests results obtained with the detector and imaging systems

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

    Energy Technology Data Exchange (ETDEWEB)

    Sergio Zimmermann et al.

    2001-03-20

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

  1. Tests of innovative photon detectors and integrated electronics for the large-area CLAS12 ring-imaging Cherenkov detector

    Energy Technology Data Exchange (ETDEWEB)

    Contalbrigo, Marco [INFN, Ferrara, Italy

    2015-07-01

    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab. Its aim is to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to perform precision measurements in hadron spectroscopy. The adopted solution foresees a novel hybrid optics design based on an aerogel radiator, composite mirrors and a densely packed and highly segmented photon detector. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). Extensive tests have been performed on Hamamatsu H8500 and novel flat multi-anode photomultipliers under development and on various types of silicon photomultipliers. A large scale prototype based on 28 H8500 MA-PMTs has been realized and tested with few GeV/c hadron beams at the T9 test-beam facility of CERN. In addition a small prototype was used to study the response of customized SiPM matrices within a temperature interval ranging from 25 down to –25 °C. The preliminary results of the individual photon detector tests and of the prototype performance at the test-beams are here reported.

  2. Tests of innovative photon detectors and integrated electronics for the large-area CLAS12 ring-imaging Cherenkov detector

    Energy Technology Data Exchange (ETDEWEB)

    Contalbrigo, M., E-mail: contalbrigo@fe.infn.it

    2015-07-01

    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab. Its aim is to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to perform precision measurements in hadron spectroscopy. The adopted solution foresees a novel hybrid optics design based on an aerogel radiator, composite mirrors and a densely packed and highly segmented photon detector. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). Extensive tests have been performed on Hamamatsu H8500 and novel flat multi-anode photomultipliers under development and on various types of silicon photomultipliers. A large scale prototype based on 28 H8500 MA-PMTs has been realized and tested with few GeV/c hadron beams at the T9 test-beam facility of CERN. In addition a small prototype was used to study the response of customized SiPM matrices within a temperature interval ranging from 25 down to −25 °C. The preliminary results of the individual photon detector tests and of the prototype performance at the test-beams are here reported.

  3. Construction of a Gas Electron Multiplier (GEM) Detector for Medical Imaging

    CERN Document Server

    Mondal, N N; Mazumdar, M R Dutta; Dubey, A K; Vioygi, Y P

    2013-01-01

    A prototype Gas Electron Multiplier (GEM) detector is under construction for medical imaging purposes. A single thick GEM of size 10x10 cm^2 is assembled inside a square shaped air-tight box which is made of Perspex glass. In order to ionize gas inside the drift field two types of voltage supplier circuits were fabricated, and array of 2x4 pads of each size 4x8 mm^2 were utilized for collecting avalanche charges. Preliminary testing results show that the circuit which produces high voltage and low current is better than that of low voltage and high current supplier circuit in terms of x-ray signal counting rates.

  4. Optical and UV Sensing Sealed Tube Microchannel Plate Imaging Detectors with High Time Resolution

    Science.gov (United States)

    Siegmund, O.; Vallerga, J.; Tremsin, A.; Hull, J.; Elam, J.; Mane, A.

    2014-09-01

    Microchannel plate (MCP) based imaging, photon time tagging detector sealed tube schemes have a unique set of operational features that enable high time resolution astronomical and remote sensing applications to be addressed. New detectors using the cross strip (XS), cross delay line (XDL), or stripline anode readouts, a wide range of photocathode types, and advanced MCP technologies have been implemented to improve many performance characteristics. A variety of sealed tubes have been developed including 18mm XS readout devices with GaAs and SuperGenII photocathodes, 25mm XDL readout devices with SuperGenII and GaN photocathodes, and 20 x 20 cm sealed tubes with bialkali photocathodes and strip line readout. One key technology that has just become viable is the ability to make MCPs using atomic layer deposition (ALD) techniques. This employs nanofabrication of the active layers of an MCP on a microcapillary array. This technique opens new performance opportunities, including, very large MCP areas (>20cm), very low intrinsic background, lower radiation induced background, much longer overall lifetime and gain stability, and markedly lower outgassing which can improve the sealed tube lifetime and ease of fabrication. The XS readout has been implemented in formats of 22mm, 50mm and 100mm, and uses MCP charge signals detected on two orthogonal layers of conductive fingers to encode event X-Y positions. We have achieved spatial resolution XS detectors better than 25 microns FWHM, with good image linearity while at low gain (5 MHz with ~12% dead time and event timing accuracy of ~100ps. XDL sealed tubes in 25mm format demonstrate ~40 micron spatial resolution at up to ~2 MHz event rates, and have been developed with SupergenII visible regime photocathodes. The XDL tubes also achieve ~100 ps time resolution. Most recently ALD MCPs with an opaque GaN photocathode (100-350nm range) on the MCP surface has been demonstrated in a sealed tube configuration. These ALD MCPs show

  5. Photoacoustic projection imaging using a 64-channel fiber optic detector array

    Science.gov (United States)

    Bauer-Marschallinger, Johannes; Felbermayer, Karoline; Bouchal, Klaus-Dieter; Veres, Istvan A.; Grün, Hubert; Burgholzer, Peter; Berer, Thomas

    2015-03-01

    In this work we present photoacoustic projection imaging with a 64-channel integrating line detector array, which average the pressure over cylindrical surfaces. For imaging, the line detectors are arranged parallel to each other on a cylindrical surface surrounding a specimen. Thereby, the three-dimensional imaging problem is reduced to a twodimensional problem, facilitating projection imaging. After acquisition of a dataset of pressure signals, a twodimensional photoacoustic projection image is reconstructed. The 64 channel line detector array is realized using optical fibers being part of interferometers. The parts of the interferometers used to detect the ultrasonic pressure waves consist of graded-index polymer-optical fibers (POFs), which exhibit better sensitivity than standard glass-optical fibers. Ultrasonic waves impinging on the POFs change the phase of light in the fiber-core due to the strain-optic effect. This phase shifts, representing the pressure signals, are demodulated using high-bandwidth balanced photo-detectors. The 64 detectors are optically multiplexed to 16 detection channels, thereby allowing fast imaging. Results are shown on a Rhodamine B dyed microsphere.

  6. Optical readout uncooled infrared imaging detector using knife-edge filter operation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Q; MIAO Z; GUO Z; DONG F; XIONG Z; WU X; CHEN D; LI C; JIAO B

    2007-01-01

    An optical readout uncooled infrared (IR) imaging detector of bimaterial cantilever array using knife-edge filter operation(KEFO) is demonstrated. The angle change of each cantilever in a focal plane array (FPA) can be simultaneously detected with a resolution of 10-5 degree. A deformation magnifying substrate-free micro-cantilever unit with multi-fold interval metallized legs is specially designed and modeled. A FPA with 160× 160 pixels is fabricated and thermal images with noise equivalent temperature difference (NETD) of 400 mK are obtained by this imaging detector.

  7. Two-dimensional photon counting imaging detector based on a Vernier position sensitive anode readout

    Institute of Scientific and Technical Information of China (English)

    鄢秋荣; 赵宝升; 刘永安; 杨颢; 盛立志; 韦永林

    2011-01-01

    A two-dimensional photon counting imaging detector based on a Vernier position sensitive anode is reported. The decode principle and design of a two-dimensional Vernier anode are introduced in detail. A photon counting imaging system was built based on a

  8. MeV X-ray imaging using plastic scintillating fiber area detectors: a simulation study.

    Science.gov (United States)

    Tang, Shi-Biao; Ma, Qingli; Yin, Zejie; Zhu, Daming

    2008-02-01

    Due to their low cost, flexibility, and convenience for long distance data transfer, plastic scintillating fibers (PSFs) have been increasingly used in building detectors or sensors for detecting various radiations and imaging. In this work, the possibility of using PSF coupled with charge-coupled devices (CCD) to build area detectors for X-ray imaging is studied using a Monte Carlo simulation. The focus is on X-ray imaging with energy from a few 100 keV to about 20 MeV. It is found that the efficiency of PSF in detecting X-ray in this energy range is low. The performance can be improved by coating a PSF with X-ray absorption layers and the MTF of the system is presented. It seems possible to build such area detectors with PSFs for imaging hard X-rays under certain environment.

  9. Large-area imaging micro-well detectors for high-energy astrophysics

    CERN Document Server

    Deines-Jones, P; Hunter, S D; Jahoda, K; Owens, S M

    2002-01-01

    Micro-well detectors are pixelized imaging sensors that can be inexpensively fabricated in very large arrays. Owing to their intrinsic gain and operation at room temperature, they can be instrumented at very low power, per unit area, making them valuable for a variety of space-flight applications where wide-angle X-ray imaging or large-area particle tracking is required. For example, micro-well detectors have been chosen as the focal plane imager for Lobster-ISS, a proposed soft X-ray all-sky monitor. We have fabricated detectors which image X-rays with 200 mu m FWHM resolution at 3 keV. In agreement with other groups using similar geometries, we find nominal proportional counter energy resolution (20% at 6 keV in P-10), and stable operation at gas gains up to 30,000.

  10. 2D dose distribution images of a hybrid low field MRI-γ detector

    Science.gov (United States)

    Abril, A.; Agulles-Pedrós, L.

    2016-07-01

    The proposed hybrid system is a combination of a low field MRI and dosimetric gel as a γ detector. The readout system is based on the polymerization process induced by the gel radiation. A gel dose map is obtained which represents the functional part of hybrid image alongside with the anatomical MRI one. Both images should be taken while the patient with a radiopharmaceutical is located inside the MRI system with a gel detector matrix. A relevant aspect of this proposal is that the dosimetric gel has never been used to acquire medical images. The results presented show the interaction of the 99mTc source with the dosimetric gel simulated in Geant4. The purpose was to obtain the planar γ 2D-image. The different source configurations are studied to explore the ability of the gel as radiation detector through the following parameters; resolution, shape definition and radio-pharmaceutical concentration.

  11. COMPARISON OF WIRELESS DETECTORS FOR DIGITAL RADIOGRAPHY SYSTEMS: IMAGE QUALITY AND DOSE.

    Science.gov (United States)

    Mourik, J E M; van der Tol, P; Veldkamp, W J H; Geleijns, J

    2016-06-01

    The purpose of this study was to compare dose and image quality of wireless detectors for digital chest radiography. Entrance dose at both the detector (EDD) and phantom (EPD) and image quality were measured for wireless detectors of seven different vendors. Both the local clinical protocols and a reference protocol were evaluated. In addition, effective dose was calculated. Main differences in clinical protocols involved tube voltage, tube current, the use of a small or large focus and the use of additional filtration. For the clinical protocols, large differences in EDD (1.4-11.8 µGy), EPD (13.9-80.2 µGy) and image quality (IQFinv: 1.4-4.1) were observed. Effective dose was systems. Although effective dose is low, further improvement of imaging technology and acquisition protocols is warranted for optimisation of digital chest radiography.

  12. Silicon strip detectors for two-dimensional soft X-ray imaging at normal incidence

    Energy Technology Data Exchange (ETDEWEB)

    Rato Mendes, P. E-mail: rato@lip.pt; Abreu, M.C.; Baldazzi, G.; Bollini, D.; Cabal Rodriguez, A.E.; Dabrowski, W.; Diaz Garcia, A.; Gambaccini, M.; Giubellino, P.; Gombia, M.; Grybos, P.; Idzik, M.; Marzari-Chiesa, A.; Montano, L.M.; Prino, F.; Ramello, L.; Rodrigues, S.; Sitta, M.; Sousa, P.; Swientek, K.; Taibi, A.; Tuffanelli, A.; Wheadon, R.; Wiacek, P

    2003-08-21

    A simple prototype system for static two-dimensional soft X-ray imaging using silicon microstrip detectors irradiated at normal incidence is presented. Radiation sensors consist of single-sided silicon detectors made from 300 {mu}m thick wafers, read by RX64 ASICs. Data acquisition and control is performed by a Windows PC workstation running dedicated LabVIEW routines, connected to the sensors through a PCI-DIO-96 interface. Two-dimensional images are obtained by scanning a lead collimator with a thin slit perpendicular to the strip axis, along the whole detector size; the several strip profiles (slices) taken at each position are then put together to form a planar image. Preliminary results are presented, illustrating the high-resolution imaging capabilities of the system with soft X-rays.

  13. High-resolution imaging X-ray detector. [using microchannel plates and electronic readout for spaceborne telescope

    Science.gov (United States)

    Kellogg, E.; Henry, P.; Murray, S.; Van Speybroeck, L.; Bjorkholm, P.

    1976-01-01

    The paper describes an X-ray detector using microchannel plates as a photocathode surface and imaging photoelectron multiplier, and a crossed wire grid as a two-dimensional position-sensitive detector. The position resolution is 10 microns. The crossed wire grid consists of 100-micron-diam wires on 200-micron centers. Position sensing is accomplished by electronic interpolation to 1/20 of the wire spacing. The quantum efficiency of the microchannel plates varies from 29% at 0.28 keV to 5% at 3 keV. This detector will provide second-of-arc X-ray imaging in the focal plane of the 342.9-cm focal length grazing-incidence telescope being prepared for the HEAO-B observatory. By addition of suitable photocathodes, it can be used for single-photon imaging light detection in the UV, visible, and near-IR-ranges. In all cases, it gives a very low dark counting rate, allows timing of individual events to 1 microsec or less, and can handle counting rates up to 10,000 per sec.

  14. Comparison of spectral CT imaging methods based a photon-counting detector: Experimental study

    Science.gov (United States)

    Lee, Youngjin; Lee, Seungwan; Kim, Hee-Joung

    2016-04-01

    Photon-counting detectors allow spectral computed tomography (CT) imaging using energy-resolved information from a polychromatic X-ray spectrum. The spectral CT images based on the photon-counting detectors are dependent on the energy ranges defined by energy bins for image acquisition. In this study, K-edge and energy weighting imaging methods were experimentally implemented by using a spectral CT system with a cadmium zinc telluride (CZT)-based photon-counting detector. The spectral CT images were obtained by various energy bins and compared in terms of CNR improvement for investigating the effect of energy bins and the efficiency of the spectral CT imaging methods. The results showed that the spectral CT image quality was improved by using the particular energy bins, which were optimized for each spectral CT imaging method and target material. The CNR improvement was different for the spectral CT imaging methods and target materials. It can be concluded that an appropriate selection of imaging method for each target material and the optimization of energy bin can maximize the quality of spectral CT images.

  15. Comparison of spectral CT imaging methods based a photon-counting detector: Experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngjin [Department of Radiological Science, College of Health Science, Eulji University, 553 Sangseong-daero, Seongnam, Gyeonggi-do 461-713 (Korea, Republic of); Lee, Seungwan, E-mail: slee1@konyang.ac.kr [Department of Radiological Science, College of Medical Science, Konyang University, 158 Gwanjeodong-ro, Daejeon 302-812 (Korea, Republic of); Kim, Hee-Joung [Department of Radiological Science, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Kangwon-do 220-710 (Korea, Republic of)

    2016-04-11

    Photon-counting detectors allow spectral computed tomography (CT) imaging using energy-resolved information from a polychromatic X-ray spectrum. The spectral CT images based on the photon-counting detectors are dependent on the energy ranges defined by energy bins for image acquisition. In this study, K-edge and energy weighting imaging methods were experimentally implemented by using a spectral CT system with a cadmium zinc telluride (CZT)-based photon-counting detector. The spectral CT images were obtained by various energy bins and compared in terms of CNR improvement for investigating the effect of energy bins and the efficiency of the spectral CT imaging methods. The results showed that the spectral CT image quality was improved by using the particular energy bins, which were optimized for each spectral CT imaging method and target material. The CNR improvement was different for the spectral CT imaging methods and target materials. It can be concluded that an appropriate selection of imaging method for each target material and the optimization of energy bin can maximize the quality of spectral CT images.

  16. The DEPFET detector-amplifier structure for spectroscopic imaging in astronomy and for experiments at free electron lasers

    Science.gov (United States)

    Lutz, G.; Aschauer, S.; Majewski, P.; Holl, P.; Strüder, L.

    2017-02-01

    The DEPFET detector-amplifier structure possesses several unique properties which make it extremely useful as readout element in semiconductor detectors and in particular as building block of semiconductor pixel detectors. Variations of DEPFETs can be tuned to specific requirements as to be sensitive only in predetermined time intervals, to measure signal charge with sub-electron precision, dead-time-free readout and with signal compression. These devices have been shown to work in simulations and in prototypes. Recently the first two fully developed detector systems have been finished and installed in the MIXS (Mercury Image X-ray Spectrometer) instrument of the Mercury Planetary Orbiter scheduled to be launched in 2017. A further DEPFET detector system under development is the DSSC (Depfet Sensor with Signal Compression) that will be installed in one of the beam-lines of XFEL. The requirements of the two projects are rather different. While the MIXS sensors are supposed to measure precisely the energy and position of single photons down to very low energies but at moderate rates, the DSSC has to measure the number of photons arriving in each pixel within a time interval of 220 ns. Here the challenge is the capability of detecting single X-ray photons in one pixel simultaneously with up to 10,000 photons in some other pixels. Device functioning has been verified with sensors produced in a research laboratory. Now process and design have been adapted to an industrial type production line, allowing additional improvements.

  17. IR Imaging Using Arrays of SiO2 Micromechanical Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Grbovic, Dragoslav [ORNL; Lavrik, Nickolay V [ORNL; Rajic, Slobodan [ORNL; Datskos, Panos G [ORNL; Hunter, Scott Robert [ORNL

    2012-01-01

    In this letter, we describe the fabrication of an array of bimaterial detectors for infrared (IR) imaging that utilize SiO2 as a structural material. All the substrate material underneath the active area of each detector element was removed. Each detector element incorporates an optical resonant cavity layer in the IR absorbing region of the sensing element. The simplified microfabrication process requires only four photolithographic steps with no wet etching or sacrificial layers. The thermomechanical deflection sensitivity was 7.9 10-3 rad/K which corresponds to a noise equivalent temperature difference (NETD) of 2.9 mK. In the present work the array was used to capture IR images while operating at room temperature and atmospheric pressure and no need for vacuum packaging. The average measured NETD of our IR detector system was approximately 200 mK but some sensing elements exhibited an NETD of 50 mK.

  18. A multi-channel high time resolution detector for high content imaging

    CERN Document Server

    Lapington, J S; Miller, G M; Ashton, T J R; Jarron, P; Despeisse, M; Powolny, F; Howorth, J; Milnes, J

    2009-01-01

    Medical imaging has long benefited from advances in photon counting detectors arising from space and particle physics. We describe a microchannel plate-based detector system for high content (multi-parametric) analysis, specifically designed to provide a step change in performance and throughput for measurements in imaged live cells and tissue for the ‘omics’. The detector system integrates multi-channel, high time resolution, photon counting capability into a single miniaturized detector with integrated ASIC electronics, comprising a fast, low power amplifier discriminator and TDC for every channel of the discrete pixel electronic readout, and achieving a pixel density improvement of order two magnitudes compared with current comparable devices. The device combines high performance, easy reconfigurability, and economy within a compact footprint. We present simulations and preliminary measurements in the context of our ultimate goals of 20 ps time resolution with multi-channel parallel analysis (1024 chan...

  19. New detector for spread-spectrum based image watermarking using underdetermined ICA

    Science.gov (United States)

    Malik, Hafiz; Khokhar, Ashfaq; Ansari, Rashid

    2006-02-01

    This paper presents a novel scheme for detection of watermarks embedded in multimedia signals using spread spectrum (SS) techniques. The detection method is centered on using the model that the embedded watermark and the host signal are mutually independent. The proposed detector assumes that the host signal and the watermark obey non-Gaussian distributions. The proposed blind watermark detector employs underdetermined blind source separation (BSS) based on independent component analysis (ICA) for watermark estimation from the watermarked image. The mean-field theory based undetermined BSS scheme is used for watermark estimation. Analytical results are presented showing that the proposed detector performs significantly better than the existing correlation based blind detectors traditionally used for SS-based image watermarking.

  20. Study of the electron → photon misidentification rate in the ATLAS detector

    CERN Document Server

    Haase, Johannes

    In this thesis, the misidentification of electrons as photons (fake rate) is investigated using the first 7 TeV data of the ATLAS detector at the CERN Large Hadron Collider. A method for the measurement of the fake rate in data, using pure electrons from the Z0 → e+e− decay, called tag-and-probe, is presented. The results are studied as functions of kinematic variables in order to show effects on the detector performance. A cross check with a so-called truth-matching method in Monte Carlo is applied. In addition, the fake rate for Gauge Mediated Supersymmetry Breaking events is estimated and compared with Z0 → e+e− studies.

  1. Feature Based Image Mosaic Using Steerable Filters and Harris Corner Detector

    Directory of Open Access Journals (Sweden)

    Mahesh

    2013-05-01

    Full Text Available Image mosaic is to be combine several views of a scene in to single wide angle view. This paper proposes the feature based image mosaic approach. The mosaic image system includes feature point detection, feature point descriptor extraction and matching. A RANSAC algorithm is applied to eliminate number of mismatches and obtain transformation matrix between the images. The input image is transformed with the correct mapping model for image stitching and same is estimated. In this paper, feature points are detected using steerable filters and Harris, and compared with traditional Harris, KLT, and FAST corner detectors.

  2. Non-volatile resistive photo-switches for flexible image detector arrays

    Science.gov (United States)

    Nau, Sebastian; Wolf, Christoph; Sax, Stefan; List-Kratochvil, Emil J. W.

    2015-09-01

    The increasing quest to find lightweight, conformable or flexible image detectors for machine vision or medical imaging brings organic electronics into the spotlight for these fields of application. Here were we introduce a unique imaging device concept and its utilization in an organic, flexible detector array with simple passive matrix wiring. We present a flexible organic image detector array built up from non-volatile resistive multi-bit photo-switchable elements. This unique realization is based on an organic photodiode combined with an organic resistive memory device wired in a simple crossbar configuration. The presented concept exhibits significant advantages compared to present organic and inorganic detector array technologies, facilitating the detection and simultaneous storage of the image information in one detector pixel, yet also allowing for simple read-out of the information from a simple passive-matrix crossbar wiring. This concept is demonstrated for single photo-switchable pixels as well as for arrays with sizes up to 32 by 32 pixels (1024 bit). The presented results pave the way for a versatile flexible and easy-to-fabricate sensor array technology. In a final step, the concept was expanded to detection of x-rays.

  3. Spatial and temporal image characteristics of a real-time large area a-Se x-ray detector

    Science.gov (United States)

    Tousignant, Olivier; Demers, Yves; Laperriere, Luc; Mani, Habib; Gauthier, Philippe; Leboeuf, Jonathan

    2005-04-01

    Large area, real-time, amorphous selenium (a-Se) based Flat Panel Detectors (FPD) were recently equipped with low noise front end electronics. In full resolution, 14"x14" detectors (FPD14) and 9"x9" detectors (FPD9) show an electronic noise of 1400 electrons. To evaluate the positive impact of such low noise on image quality, a dedicated report on spatial characteristics (MTF, NPS and DQE) covering the low dose range from 0.6 μR to 12 μR per frame, will be presented in the first section of this paper. For one RQA5 beam quality, DQE corrected for lag extrapolated at zero spatial frequency was equal to 0.6 for quantum noise limited exposure and equal to 0.4 for 0.6 μR. Almost no difference was found between 1x1 and 2x2 resolution mode giving the opportunity to 1x1 fluoroscopy. Recent advances to reduce image temporal artifacts such as lag and ghost will make the second part of this paper. It is demonstrated that the most significant contribution to detector lag is coming from the PIN selenium structure. Above electric field of 10 V/μm charges release from traps following one x-ray exposure could not explain selenium lag. Active ghost correction based on deep trapped charge recombination was developed giving good preliminary results in showing no residual ghost for a high dose rate of 33 mR/min.

  4. Comparison of ring artifact removal methods using flat panel detector based CT images

    OpenAIRE

    2011-01-01

    Abstract Background Ring artifacts are the concentric rings superimposed on the tomographic images often caused by the defective and insufficient calibrated detector elements as well as by the damaged scintillator crystals of the flat panel detector. It may be also generated by objects attenuating X-rays very differently in different projection direction. Ring artifact reduction techniques so far reported in the literature can be broadly classified into two groups. One category of the approac...

  5. Lorentz angle studies for the SLD endcap Cerenkov Ring Imaging Detector

    Energy Technology Data Exchange (ETDEWEB)

    Coyle, P.; Cavalli-Sforza, M.; Coyne, D.; Schneider, M.; Spencer, E.; Williams, D.; Ashford, V.; Bienz, T.; Bird, F.; Gaillard, M.

    1987-11-01

    The design of the endcap Cerenkov Ring Imaging Detectors for SLD requires a detailed understanding of how electrons drift in gases under the influence of crossed electric and magnetic fields. In this report, we present recent measurements of Lorentz angles and drift velocities in gases suitable for the endcap CRID photon detectors. We compare these measurements to predictions from a theoretical model; good agreement is observed. Based on our results we present a design for detectors operating in a 0.6 Tesla transverse magnetic field. 14 refs., 10 figs., 4 tabs.

  6. Fast triggering of high-rate charged particles with a triple-GEM detector

    CERN Document Server

    Alfonsi, M; Bonivento, W; Cardini, A; De Simone, P; Murtas, F; Pinci, D; Poli-Lener, M; Raspino, D

    2004-01-01

    A 3 year long R&D activity on triple gas electron multiplier (GEM) detectors is reported. This activity was made in the framework of the LHCb experiment in order to find the technology to instrument the central region of the first muon station (M1R1) where a high particle rate is expected. Detector geometry, gas mixture and electric field configuration have been optimized in order to achieve the performance required by the experiment. The use of a very fast, CF//4 based, gas mixture provides a time resolution of about 4.5 ns (r.m.s.) with a single chamber with gain less than 10**4. In addition, an optimized gain sharing between the three GEMs allows to keep the discharge probability per incident hadron below $10^{-12}$. The average number of firing pads per crossing particle have been found to be lower than 1.2. In a global aging test two detectors were exposed to a dose rate of 16 Gy/h. Each detector integrated about 2 C/cm**2 equivalent to more than 10 years of operation at LHCb. Good aging properties w...

  7. Alternative method to determine the bulk etch rate of Lr-115 detectors

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, D.; Sajo B, L.; Barros, H.; Greaves, E. D. [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apdo. Postal 89000, Caracas (Venezuela, Bolivarian Republic of); Palacios, F. [Universidad de Oriente, Santiago de Cuba (Cuba)

    2010-02-15

    The measurements using the Lr-115 solid-state nuclear track detector depend critically on the removed thickness of the active layer during etching. In this work, Lr-115 detectors exposed to alpha particles were etched under no stirring in a 2.5 N NaOH solution at a temperature of 60{+-}1 C and different etching times (from 0.5 to 2.5 hours). The thickness of the removed layer was determined by a variant of the gravimetric method, so that the bulk etch rate could be deduced from mass change measurements of detectors. The bulk etch rate was found to be 3.63 {+-} 0.09 {mu}m.h{sup -}1, which agrees with most of the reported values. Comparisons of our results with the obtained by the optical density method are in correspondence. We propose here a fast, simple, and nondestructive method to determine the active-layer thickness of the Lr-115 solid-state nuclear track detector with good accuracy for routine measurements. (Author)

  8. 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 ...

  9. Evaluation of controlled-drift detectors in X-ray spectroscopic imaging applications.

    Science.gov (United States)

    Castoldi, Andrea; Guazzoni, Chiara; Ozkan, Cigdem; Vedani, Giorgio; Hartmann, Robert; Bjeoumikhov, Aniouar

    2009-06-01

    A detector that looks promising for advanced imaging modalities--such as X-ray absorption contrast imaging, X-ray fluorescence imaging, and diffraction-enhanced imaging--is the controlled-drift detector (CDD). The CDD is a novel two-dimensional X-ray imager with energy resolving capability of spectroscopic quality. It is built on a fully depleted silicon wafer and features fast readout while being operated at or near room temperature. The use of CDDs in the aforementioned applications allows translating these techniques from synchrotron-based experiments to laboratory-size experiments using polychromatic X-ray generators. We have built a dedicated and versatile detection module based on a 36 mm2 CDD chip featuring pixels of 180 x 180 microm 2, and we evaluated the system performance in different X-ray imaging applications both with synchrotron-based experiments and in the laboratory environment.

  10. Superiority of zoom lens coupling in designing a novel X-ray image detector

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We design a novel X-ray image detector by lens coupling a Gd2O2S:Tb intensifying screen with a high performance low-light-level (L3,which often means luminescence less than 10-3 Lux) image intensifier.Different coupling effects on imaging performance between zoom lens and fix-focus lens are analyzed theoretically.In experiment,for designing a detector of 15-inch visual field,the system coupled by zoom lens is of 12.25-1p/cm resolution,while the one with fix-focus lens is 10 lp/cm.The superiority of zoom lens is validated.It is concluded that zoom lens preserves the image information better than fix-focus lens and improves the imaging system's performance in this design,which is referential to the design of other optical imaging systems.

  11. 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

  12. A high resolution, high frame rate detector based on a microchannel plate read out with the Medipix2 counting CMOS pixel chip.

    CERN Document Server

    Mikulec, Bettina; McPhate, J B; Tremsin, A S; Siegmund, O H W; Clark, Allan G; CERN. Geneva

    2005-01-01

    The future of ground-based optical astronomy lies with advancements in adaptive optics (AO) to overcome the limitations that the atmosphere places on high resolution imaging. A key technology for AO systems on future very large telescopes are the wavefront sensors (WFS) which detect the optical phase error and send corrections to deformable mirrors. Telescopes with >30 m diameters will require WFS detectors that have large pixel formats (512x512), low noise (<3 e-/pixel) and very high frame rates (~1 kHz). These requirements have led to the idea of a bare CMOS active pixel device (the Medipix2 chip) functioning in counting mode as an anode with noiseless readout for a microchannel plate (MCP) detector and at 1 kHz continuous frame rate. First measurement results obtained with this novel detector are presented both for UV photons and beta particles.

  13. Feasibility study of a dual detector configuration concept for simultaneous megavoltage imaging and dose verification in radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, Shrikant, E-mail: shrikant.Deshpande@sswahs.nsw.gov.au [Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Sydney NSW 2170 (Australia); Centre for Medical Radiation Physics, University of Wollongong, Wollongong NSW 2170 (Australia); Ingham Institute for Applied Medical Research, Sydney, NSW 2170 (Australia); McNamara, Aimee L. [Ingham Institute for Applied Medical Research, Sydney, NSW 2170, Australia and Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); Holloway, Lois [Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Sydney NSW 2170 (Australia); Centre for Medical Radiation Physics, University of Wollongong, Wollongong NSW 2170 (Australia); Ingham Institute for Applied Medical Research, Sydney, NSW 2170 (Australia); Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); South Western Sydney Clinical School, University of New South Wales, Sydney, NSW 2052 (Australia); Metcalfe, Peter [Centre for Medical Radiation Physics, University of Wollongong, Wollongong NSW 2170 (Australia); Ingham Institute for Applied Medical Research, Sydney, NSW 2170 (Australia); Vial, Philip [Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Sydney NSW 2170 (Australia); Ingham Institute for Applied Medical Research, Sydney, NSW 2170 (Australia); Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia)

    2015-04-15

    IMRT test patterns and clinical IMRT beams had gamma pass rates of ≥98% at 2%/2 mm criteria. In terms of imaging performance, the measured CNR and spatial resolution (f{sub 50}) were 263.23 ± 24.85 and 0.4025 ± 1.25 × 10{sup −3} for dual detector configuration and 324 ± 26.65 and 0.4141 ± 1.14 × 10{sup −3} for reference imaging configuration, respectively. The CNR and spatial resolution were quantitatively worse in the dual detector configuration due to the additional backscatter. The difference in imaging performance was not visible in qualitative assessment of phantom images. Conclusions: Combining a commercially available ICA dosimetry device with a conventional EPID did not significantly detract from the performance of either device. Further improvements in imaging performance may be achieved with an optimized design. This study demonstrates the feasibility of a dual detector concept for simultaneous imaging and dosimetry in radiation therapy.

  14. Simultaneous x-ray fluorescence and K-edge CT imaging with photon-counting detectors

    Science.gov (United States)

    Li, Liang; Li, Ruizhe; Zhang, Siyuan; Chen, Zhiqiang

    2016-10-01

    Rapid development of the X-ray phonon-counting detection technology brings tremendous research and application opportunities. In addition to improvements in conventional X-ray imaging performance such as radiation dose utilization and beam hardening correction, photon-counting detectors allows significantly more efficient X-ray fluorescence (XRF) and K-edge imaging, and promises a great potential of X-ray functional, cellular and molecular imaging. XRF is the characteristic emission of secondary X-ray photons from a material excited by initial X-rays. The phenomenon is widely used for chemical and elemental analysis. K-edge imaging identifies a material based on its chemically-specific absorption discontinuity over X-ray photon energy. In this paper, we try to combine XRF and K-edge signals from the contrast agents (e.g., iodine, gadolinium, gold nanoparticles) to simultaneously realize XFCT and K-edge CT imaging for superior image performance. As a prerequisite for this dual-modality imaging, the accurate energy calibration of multi-energy-bin photon-counting detectors is critically important. With the measured XRF data of different materials, we characterize the energy response function of a CZT detector for energy calibration and spectrum reconstruction, which can effectively improve the energy resolution and decrease the inconsistence of the photon counting detectors. Then, a simultaneous K-edge and X-ray fluorescence CT imaging (SKYFI) experimental setup is designed which includes a cone-beam X-ray tube, two separate photon counting detector arrays, a pin-hole collimator and a rotation stage. With a phantom containing gold nanoparticles the two types of XFCT and K-edge CT datasets are collected simultaneously. Then, XFCT and K-edge CT images are synergistically reconstructed in a same framework. Simulation results are presented and quantitative analyzed and compared with the separate XFCT and K-edge CT results.

  15. Influence of image acquisition settings on radiation dose and image quality in coronary angiography by 320-detector volume computed tomography: the CORE320 pilot experience

    Directory of Open Access Journals (Sweden)

    Armin Arbab-Zadeh

    2012-06-01

    Full Text Available The objective of this study was to investigate the impact of image acquisition settings and patients’ characteristics on image quality and radiation dose for coronary angiography by 320-row computed tomography (CT. CORE320 is a prospective study to investigate the diagnostic performance of 320-detector CT for detecting coronary artery disease and associated myocardial ischemia. A run-in phase in 65 subjects was conducted to test the adequacy of the computed tomography angiography (CTA acquisition protocol. Tube current, exposure window, and number of cardiac beats per acquisition were adjusted according to subjects’ gender, heart rate, and body mass index (BMI. Main outcome measures were image quality, assessed by contrast/noise measurements and qualitatively on a 4-point scale, and radiation dose, estimated by the dose-length-product. Average heart rate at image acquisition was 55.0±7.3 bpm. Median Agatston calcium score was 27.0 (interquartile range 1-330. All scans were prospectively triggered. Single heart beat image acquisition was obtained in 61 of 65 studies (94%. Sixty-one studies (94% and 437 of 455 arterial segments (96% were of diagnostic image quality. Estimated radiation dose was significantly greater in obese (5.3±0.4 mSv than normal weight (4.6±0.3 mSv or overweight (4.7±0.3 mSv subjects (P<0.001. BMI was the strongest factor influencing image quality (odds ratio=1.457, P=0.005. The CORE320 CTA image acquisition protocol achieved a good balance between image quality and radiation dose for a 320-detector CT system. However, image quality in obese subjects was reduced compared to normal weight subjects, possibly due to tube voltage/current restrictions mandated by the study protocol.

  16. A comparison of interest point and region detectors on structured, range and texture images

    DEFF Research Database (Denmark)

    Kazmi, Wajahat; Andersen, Hans Jørgen

    2015-01-01

    )) and corner based detectors (such as Hessian and Harris with both Affine/Laplace variants, SURF with determinant of Hessian based corners and SIFT with difference of Gaussians) acquired more than 90% mean average precision, whereas on range images, homogeneous region detector did not work well. TLR offered...... and textured images. It is also shown that in a bi-channel approach, combining surface and edge regions (MSER and TLR) boosts the overall performance. Among the descriptors, SIFT and SURF generally offer higher performance but low dimensional descriptors such as Steerable Filters follow closely.......This article presents an evaluation of the image retrieval and classification potential of local features. Several affine invariant region and scale invariant interest point detectors in combination with well known descriptors were evaluated. Tests on building, range and texture databases were...

  17. Timing and position response of a block detector for fast neutron time-of-flight imaging

    Science.gov (United States)

    Laubach, M. A.; Hayward, J. P.; Zhang, X.; Cates, J. W.

    2014-11-01

    Our research effort seeks to improve the spatial and timing performance of a block detector made of a pixilated plastic scintillator (EJ-200), first demonstrated as part of Oak Ridge National Laboratory's Advanced Portable Neutron Imaging System. Improvement of the position and time response is necessary to achieve better resolution and contrast in the images of shielded special nuclear material. Time-of-flight is used to differentiate between gamma and different sources of neutrons (e.g., transmission and fission neutrons). Factors limiting the timing and position performance of the neutron detector have been revealed through simulations and measurements. Simulations have suggested that the degradation in the ability to resolve pixels in the neutron detector is due to those interactions occurring near the light guide. The energy deposition within the neutron detector is shown to affect position performance and imaging efficiency. This examination details how energy cuts improve the position performance and degrade the imaging efficiency. Measurements have shown the neutron detector to have a timing resolution of σ=238 ps. The majority of this timing uncertainty is from the depth-of-interaction (DOI) of the neutron which is confirmed by simulations and analytical calculations.

  18. Assessment of array scintillation detector for follicle thyroid 2-D image acquisition using Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Carlos Borges da; Santanna, Claudio Reis de [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)]. E-mails: borges@ien.gov.br; santanna@ien.gov.br; Braz, Delson [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Instrumentacao Nuclear]. E-mail: delson@lin.ufrj.br; Carvalho, Denise Pires de [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Biofisica Carlos Chagas Filho. Lab. de Fisiologia Endocrina]. E-mail: dencarv@ufrj.br

    2007-07-01

    This work presents an innovative study to find out the adequate scintillation inorganic detector array to be used coupled to a specific light photo sensor, a charge coupled device (CCD), through a fiber optic plate. The goal is to choose the type of detector that fits a 2-dimensional imaging acquisition of a cell thyroid tissue application with high resolution and detection efficiency in order to map a follicle image using gamma radiation emission. A point or volumetric source - detector simulation by using a MCNP4B general code, considering different source energies, detector materials and geometry including pixel sizes and reflector types was performed. In this study, simulations were performed for 7 x 7 and 127 x 127 arrays using CsI(Tl) and BGO scintillation crystals with pixel size ranging from 1 x 1 cm{sup 2} to 10 x 10 {mu}m{sup 2} and radiation thickness ranging from 1 mm to 10 mm. The effect of all these parameters was investigated to find the best source-detector system that result in an image with the best contrast details. The results showed that it is possible to design a specific imaging system that allows searching for in-vitro studies, specifically in radiobiology applied to endocrine physiology. (author)

  19. Digital X-ray imaging using silicon microstrip detectors: a design study

    Science.gov (United States)

    Speller, R. D.; Royle, G. J.; Triantis, F. A.; Manthos, N.; Van der Stelt, P. F.; di Valentin, M.

    2001-01-01

    This paper considers the basic design parameters for using silicon microstrip detectors for 2-D medical imaging. In particular, mammographic and dental imaging are considered. Monte Carlo modeling techniques have been used to investigate detector efficiency, strip pitch, image quality, imaging geometry and signal processing requirements. Different phantoms are used for each part of the study. It is shown that signal processing times are a major factor in the operation of a clinical detector system if ambiguities are to be avoided in a double-sided strip detector. However, the use of the models allows conclusions to be made that alleviate the timing requirements. It has been shown that using a strip structure of 50-100 μm provides appropriate image resolution and image quality can be maintained with pixel counts of 50-100 in both dental and mammographic work. Under these conditions current front-end electronics designs can provide the signal processing times with an acceptably small number of multihit events (<5%).

  20. 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...

  1. High frame rate imaging based photometry

    DEFF Research Database (Denmark)

    Harpsøe, Kennet Bomann West; Jørgensen, U. G.; Andersen, M. I.;

    2012-01-01

    in conventional CCDs, and new methods for handling these must be developed. We aim to investigate how the normal photometric reduction steps from conventional CCDs should be adjusted to be applicable to EMCCD data. One complication is that a bias frame cannot be obtained conventionally, as the output from...... an EMCCD is not normally distributed. Also, the readout process generates spurious charges in any CCD, but in EMCCD data, these charges are visible as opposed to the conventional CCD. Furthermore we aim to eliminate the photon waste associated with lucky imaging by combining this method with shift......-and-add. A simple probabilistic model for the dark output of an EMCCD is developed. Fitting this model with the expectation-maximization algorithm allows us to estimate the bias, readout noise, amplification, and spurious charge rate per pixel and thus correct for these phenomena. To investigate the stability...

  2. Performance evaluation of a very high resolution small animal PET imager using silicon scatter detectors

    Science.gov (United States)

    Park, Sang-June; Rogers, W. Leslie; Huh, Sam; Kagan, Harris; Honscheid, Klaus; Burdette, Don; Chesi, Enrico; Lacasta, Carlos; Llosa, Gabriela; Mikuz, Marko; Studen, Andrej; Weilhammer, Peter; Clinthorne, Neal H.

    2007-05-01

    A very high resolution positron emission tomography (PET) scanner for small animal imaging based on the idea of inserting a ring of high-granularity solid-state detectors into a conventional PET scanner is under investigation. A particularly interesting configuration of this concept, which takes the form of a degenerate Compton camera, is shown capable of providing sub-millimeter resolution with good sensitivity. We present a Compton PET system and estimate its performance using a proof-of-concept prototype. A prototype single-slice imaging instrument was constructed with two silicon detectors 1 mm thick, each having 512 1.4 mm × 1.4 mm pads arranged in a 32 × 16 array. The silicon detectors were located edgewise on opposite sides and flanked by two non-position sensitive BGO detectors. The scanner performance was measured for its sensitivity, energy, timing, spatial resolution and resolution uniformity. Using the experimental scanner, energy resolution for the silicon detectors is 1%. However, system energy resolution is dominated by the 23% FWHM BGO resolution. Timing resolution for silicon is 82.1 ns FWHM due to time-walk in trigger devices. Using the scattered photons, time resolution between the BGO detectors is 19.4 ns FWHM. Image resolution of 980 µm FWHM at the center of the field-of-view (FOV) is obtained from a 1D profile of a 0.254 mm diameter 18F line source image reconstructed using the conventional 2D filtered back-projection (FBP). The 0.4 mm gap between two line sources is resolved in the image reconstructed with both FBP and the maximum likelihood expectation maximization (ML-EM) algorithm. The experimental instrument demonstrates sub-millimeter resolution. A prototype having sensitivity high enough for initial small animal images can be used for in vivo studies of small animal models of metabolism, molecular mechanism and the development of new radiotracers.

  3. A streamer tube detector for operation at high rates in the CPLEAR experiment at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Bennet, J.M. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Carroll, M. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Cawley, E.L. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Dodgson, M. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Fry, J.R. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Gabathuler, E. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Gamet, R. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Harrison, P. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Harrison, P.F. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Haselden, A.R. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Hayman, P.J. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; King, D. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Maley, P.D. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Sacks, L.E. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Sanders, P.M. [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.

    1996-06-01

    The design and instrumentation of a streamer tube detector for operation in the high rate environment of the CPLEAR experiment at CERN is described. A study of gas mixtures for use in the streamer tube is discussed. The final mixture of 46% argon, 50% isobutane, 4% methylal and 0.01% freon produces an axial resolution of 1.5 cm with an efficiency of 98% per layer. (orig.).

  4. Development and characterisation of new high-rate muon drift tube detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bittner, Bernhard

    2012-07-25

    With the increase of the LHC luminosity above the design value and the higher background counting rates, detectors in the ATLAS muon spectrometer have to be replaced because the limits of the radiation tolerance will be exceeded. Therefore drift tube chambers with 15 mm tube diameter were developed. The required construction accuracy was verified and the limits of the resolution and efficiency were determined in a muon beam and under gamma irradiation and compared to model expectations.

  5. Workflow for the use of a high-resolution image detector in endovascular interventional procedures

    Science.gov (United States)

    Rana, R.; Loughran, B.; Swetadri Vasan, S. N.; Pope, L.; Ionita, C. N.; Siddiqui, A.; Lin, N.; Bednarek, D. R.; Rudin, S.

    2014-03-01

    Endovascular image-guided intervention (EIGI) has become the primary interventional therapy for the most widespread vascular diseases. These procedures involve the insertion of a catheter into the femoral artery, which is then threaded under fluoroscopic guidance to the site of the pathology to be treated. Flat Panel Detectors (FPDs) are normally used for EIGIs; however, once the catheter is guided to the pathological site, high-resolution imaging capabilities can be used for accurately guiding a successful endovascular treatment. The Micro-Angiographic Fluoroscope (MAF) detector provides needed high-resolution, high-sensitivity, and real-time imaging capabilities. An experimental MAF enabled with a Control, Acquisition, Processing, Image Display and Storage (CAPIDS) system was installed and aligned on a detector changer attached to the C-arm of a clinical angiographic unit. The CAPIDS system was developed and implemented using LabVIEW software and provides a user-friendly interface that enables control of several clinical radiographic imaging modes of the MAF including: fluoroscopy, roadmap, radiography, and digital-subtraction-angiography (DSA). Using the automatic controls, the MAF detector can be moved to the deployed position, in front of a standard FPD, whenever higher resolution is needed during angiographic or interventional vascular imaging procedures. To minimize any possible negative impact to image guidance with the two detector systems, it is essential to have a well-designed workflow that enables smooth deployment of the MAF at critical stages of clinical procedures. For the ultimate success of this new imaging capability, a clear understanding of the workflow design is essential. This presentation provides a detailed description and demonstration of such a workflow design.

  6. Radon exhalation rate for phosphate rocks samples using alpha track detectors

    Directory of Open Access Journals (Sweden)

    Hesham A. Yousef

    2016-01-01

    Full Text Available Solid state nuclear track detectors are used in very broad fields of technical applications and successfully applied in different areas of environmental physics and geophysics. Radon concentration and surface exhalation rate for phosphate samples from El-Sebaeya and Abu-Tartur, Egypt, were measured using nuclear tracks detectors from types CR-39 and LR-115. The average values of radon concentration are 12711.03 and 10925.02 Bqm−3 in El-Sebaeya area using CR-39 and LR-115 detectors, respectively. Also the average values of radon concentration are 15824.16 and13601.48 Bqm−3 in Abu-Tartur area using CR-39 and LR-115 detectors, respectively. From the obtained results we can conclude that the average values of radon concentration in Abu-Tartur are higher than El-Sebaeya. The present study is important to detect any harmful radiation which, can be used as reference information to assess any changes in the radioactive background level in the surrounding environment.

  7. High resolution, multiple-energy linear sweep detector for x-ray imaging

    Science.gov (United States)

    Perez-Mendez, V.; Goodman, C.A.

    1996-08-20

    Apparatus is disclosed for generating plural electrical signals in a single scan in response to incident X-rays received from an object. Each electrical signal represents an image of the object at a different range of energies of the incident X-rays. The apparatus comprises a first X-ray detector, a second X-ray detector stacked upstream of the first X-ray detector, and an X-ray absorber stacked upstream of the first X-ray detector. The X-ray absorber provides an energy-dependent absorption of the incident X-rays before they are incident at the first X-ray detector, but provides no absorption of the incident X-rays before they are incident at the second X-ray detector. The first X-ray detector includes a linear array of first pixels, each of which produces an electrical output in response to the incident X-rays in a first range of energies. The first X-ray detector also includes a circuit that generates a first electrical signal in response to the electrical output of each of the first pixels. The second X-ray detector includes a linear array of second pixels, each of which produces an electrical output in response to the incident X-rays in a second range of energies, broader than the first range of energies. The second X-ray detector also includes a circuit that generates a second electrical signal in response to the electrical output of each of the second pixels. 12 figs.

  8. Imaging and spectroscopic performance studies of pixellated CdTe Timepix detector

    Science.gov (United States)

    Maneuski, D.; Astromskas, V.; Fröjdh, E.; Fröjdh, C.; Gimenez, E. N.; Marchal, J.; O'Shea, V.; Stewart, G.; Tartoni, N.; Wilhelm, H.; Wraight, K.; Zain, R. M.

    2012-01-01

    In this work the results on imaging and spectroscopic performances of 14 × 14 × 1 mm CdTe detectors with 55 × 55 μm and 110 × 110 μm pixel pitch bump-bonded to a Timepix chip are presented. The performance of the 110 × 110 μm pixel detector was evaluated at the extreme conditions beam line I15 of the Diamond Light Source. The energy of X-rays was set between 25 and 77 keV. The beam was collimated through the edge slits to 20 μm FWHM incident in the middle of the pixel. The detector was operated in the time-over-threshold mode, allowing direct energy measurement. Energy in the neighbouring pixels was summed for spectra reconstruction. Energy resolution at 77 keV was found to be ΔE/E = 3.9%. Comparative imaging and energy resolution studies were carried out between two pixel size detectors with a fluorescence target X-ray tube and radioactive sources. The 110 × 110 μm pixel detector exhibited systematically better energy resolution in comparison to 55 × 55 μm. An imaging performance of 55 × 55 μm pixellated CdTe detector was assessed using the Modulation Transfer Function (MTF) technique and compared to the larger pixel. A considerable degradation in MTF was observed for bias voltages below -300 V. Significant room for improvement of the detector performance was identified both for imaging and spectroscopy and is discussed.

  9. Photoeletricity Capability of Imager Detector with Coated Blends of Polymer and Perylene or Coronene

    Institute of Scientific and Technical Information of China (English)

    YANG Bing; LI Ying; XIE Ming-Gui

    2003-01-01

    Perylene and coronene have been synthesized with good yield via the Dields-Alder reaction. They have good photoluminescence properties and could transfer ultraviolet light to visible-light. To find an easy way of making a better ultraviolet charge coupled device, we blended perylene or coronene with polymers. Then, these blends were analysed by the photoluminescence spectrum. The results indicate that the blends have larger fluorescence intensity than pure perylene or coronene. Through spreading these blends on image detectors, organic image detectors with good ultraviolet photoelectricity capability were prepared.

  10. A simple algorithm for estimation of source-to-detector distance in Compton imaging.

    Science.gov (United States)

    Rawool-Sullivan, Mohini W; Sullivan, John P; Tornga, Shawn R; Brumby, Steven P

    2008-12-01

    Compton imaging is used to predict the location of gamma-emitting radiation sources. The X and Y coordinates of the source can be obtained using a back-projected image and a two-dimensional peak-finding algorithm. The emphasis of this work is to estimate the source-to-detector distance (Z). The algorithm presented uses the solid angle subtended by the reconstructed image at various source-to-detector distances. This algorithm was validated using both measured data from the prototype Compton imager (PCI) constructed at the Los Alamos National Laboratory and simulated data of the same imager. Results show this method can be applied successfully to estimate Z, and it provides a way of determining Z without prior knowledge of the source location. This method is faster than the methods that employ maximum likelihood method because it is based on simple back projections of Compton scatter data.

  11. Two-dimensional photon counting imaging detector based on a Vernier position sensitive anode readout

    Institute of Scientific and Technical Information of China (English)

    YAN Qiu-Rong; ZHAO Bao-Sheng; LIU Yong-An; YANG Hao; SHENG Li-Zhi; WEI Yong-Lin

    2011-01-01

    A two-dimensional photon counting imaging detector based on a Vernier position sensitive anode is reported. The decode principle and design of a two-dimensionai Vernier anode axe introduced in detail. A photon counting imaging system was built based on a Vernier anode. The image of very weak optical radiation can be reconstructed by image processing in a period of integration time. The resolution is superior to 100 μm according to the resolution test. The detector may realize the imaging of very weak particle flow of high- energy photons, electrons and ions, so it can be used for high-energy physics, deep space exploration, spectral measurement and bio-luminescence detection.

  12. Small animal positron emission tomography with gas detectors. Simulations, prototyping, and quantitative image reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Vernekohl, Don

    2014-04-15

    The physical background of limiting factors on spatial resolution and coincidence sensitivity were introduced, and details about the first sub-millimeter resolution preclinical PET scanner, the HIDAC, were described in this thesis. As the coincidence sensitivity of the HIDAC is rather moderate, the first subject of investigation was to study the sensitivity optimization potential of the HIDAC converter concept. The HIDAC photon converters consist of a stack of alternating conversion and insulation foils perforated with a dense matrix of holes. First, photon conversion and detection probabilities for different converter geometries were systematically explored with a Geant4 model of the HIDAC, which uses Monte-Carlo methods. Additionally, new charge transport in gas and detection models were developed, and their results for different hole dimensions were combined with the conversion probability outcomes. In a next step, it was explored whether the optimized converter hole patterns prospected by the simulations can be manufactured. In conclusion, currently only etching, screen printing, and drilling are potential methods for producing large-scale converters. Second, a test-bench was established to examine differently produced converter prototypes and to test the performance of newly developed readout electronics for the desired application. It was possible to verify that the developer version of the SPADIC works well if coupled to a MWPC/HIDAC-converter detector setup. In this combination, the setup was able to detect the majority of ionization clusters. This was validated by exploring the impact of drift thickness on the count rate. Furthermore, it was demonstrated that the test-bench is able to distinguish relative efficiency differences of converter prototypes with a precision of around 10%, if it was equipped with an extra drift layer. Additionally, single-lead-layer-converters were investigated, whereby the relative count rate difference between structured and

  13. Modelling of the small pixel effect in gallium arsenide X-ray imaging detectors

    CERN Document Server

    Sellin, P J

    1999-01-01

    A Monte Carlo simulation has been carried out to investigate the small pixel effect in highly pixellated X-ray imaging detectors fabricated from semi-insulating gallium arsenide. The presence of highly non-uniform weighting fields in detectors with a small pixel geometry causes the majority of the induced signal to be generated when the moving charges are close to the pixellated contacts. The response of GaAs X-ray imaging detectors is further complicated by the presence of charge trapping, particularly of electrons. In this work detectors are modelled with a pixel pitch of 40 and 150 mu m, and with thicknesses of 300 and 500 mu m. Pulses induced in devices with 40 mu m pixels are due almost totally to the movement of the lightly-trapped holes and can exhibit significantly higher charge collection efficiencies than detectors with large electrodes, in which electron trapping is significant. Details of the charge collection efficiencies as a function of interaction depth in the detector and of the incident phot...

  14. Positional calibrations of the germanium double sided strip detectors for the Compton spectrometer and imager

    Science.gov (United States)

    Lowell, A.; Boggs, S.; Chiu, J. L.; Kierans, C.; McBride, S.; Tseng, C. H.; Zoglauer, A.; Amman, M.; Chang, H. K.; Jean, P.; Lin, C. H.; Sleator, C.; Tomsick, J.; von Ballmoos, P.; Yang, C. Y.

    2016-08-01

    The Compton Spectrometer and Imager (COSI) is a medium energy gamma ray (0.2 - 10 MeV) imager designed to observe high-energy processes in the universe from a high altitude balloon platform. At its core, COSI is comprised of twelve high purity germanium double sided strip detectors which measure particle interaction energies and locations with high precision. This manuscript focuses on the positional calibrations of the COSI detectors. The interaction depth in a detector is inferred from the charge collection time difference between the two sides of the detector. We outline our previous approach to this depth calibration and also describe a new approach we have recently developed. Two dimensional localization of interactions along the faces of the detector (x and y) is straightforward, as the location of the triggering strips is simply used. However, we describe a possible technique to improve the x/y position resolution beyond the detector strip pitch of 2 mm. With the current positional calibrations, COSI achieves an angular resolution of 5.6 +/- 0.1 degrees at 662 keV, close to our expectations from simulations.

  15. Technical Note: Detective quantum efficiency simulation of a-Se imaging detectors using ARTEMIS.

    Science.gov (United States)

    Fang, Yuan; Ito, Takaaki; Nariyuki, Fumito; Kuwabara, Takao; Badano, Aldo; Karim, Karim S

    2017-08-01

    This work studies the detective quantum efficiency (DQE) of a-Se-based solid state x-ray detectors for medical imaging applications using ARTEMIS, a Monte Carlo simulation tool for modeling x-ray photon, electron and charged carrier transport in semiconductors with the presence of applied electric field. ARTEMIS is used to model the signal formation process in a-Se. The simulation model includes x-ray photon and high-energy electron interactions, and detailed electron-hole pair transport with applied detector bias taking into account drift, diffusion, Coulomb interactions, recombination and trapping. For experimental validation, the DQE performance of prototype a-Se detectors is measured following IEC Testing Standard 62220-1-3. Comparison of simulated and experimental DQE results show reasonable agreement for RQA beam qualities. Experimental validation demonstrated within 5% percentage difference between simulation and experimental DQE results for spatial frequency above 0.25 cycles/mm using uniform applied electric field for RQA beam qualities (RQA5, RQA7 and RQA9). Results include two different prototype detectors with thicknesses of 240 μm and 1 mm. ARTEMIS can be used to model the DQE of a-Se detectors as a function of x-ray energy, detector thickness, and spatial frequency. The ARTEMIS model can be used to improve understanding of the physics of x-ray interactions in a-Se and in optimization studies for the development of novel medical imaging applications. © 2017 American Association of Physicists in Medicine.

  16. SU-C-201-03: Coded Aperture Gamma-Ray Imaging Using Pixelated Semiconductor Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, S [Wayne State University, Detroit, MI (United States); Kaye, W; Jaworski, J [H3D, Inc., Ann Arbor, MI (United States); He, Z [University of Michigan, Ann Arbor, MI (United States)

    2015-06-15

    Purpose: Improved localization of gamma-ray emissions from radiotracers is essential to the progress of nuclear medicine. Polaris is a portable, room-temperature operated gamma-ray imaging spectrometer composed of two 3×3 arrays of thick CdZnTe (CZT) detectors, which detect gammas between 30keV and 3MeV with energy resolution of <1% FWHM at 662keV. Compton imaging is used to map out source distributions in 4-pi space; however, is only effective above 300keV where Compton scatter is dominant. This work extends imaging to photoelectric energies (<300keV) using coded aperture imaging (CAI), which is essential for localization of Tc-99m (140keV). Methods: CAI, similar to the pinhole camera, relies on an attenuating mask, with open/closed elements, placed between the source and position-sensitive detectors. Partial attenuation of the source results in a “shadow” or count distribution that closely matches a portion of the mask pattern. Ideally, each source direction corresponds to a unique count distribution. Using backprojection reconstruction, the source direction is determined within the field of view. The knowledge of 3D position of interaction results in improved image quality. Results: Using a single array of detectors, a coded aperture mask, and multiple Co-57 (122keV) point sources, image reconstruction is performed in real-time, on an event-by-event basis, resulting in images with an angular resolution of ∼6 degrees. Although material nonuniformities contribute to image degradation, the superposition of images from individual detectors results in improved SNR. CAI was integrated with Compton imaging for a seamless transition between energy regimes. Conclusion: For the first time, CAI has been applied to thick, 3D position sensitive CZT detectors. Real-time, combined CAI and Compton imaging is performed using two 3×3 detector arrays, resulting in a source distribution in space. This system has been commercialized by H3D, Inc. and is being acquired for

  17. Image-Reversal Soft Lithography: Fabrication of Ultrasensitive Biomolecular Detectors.

    Science.gov (United States)

    Safaei, Tina Saberi; Das, Jagotamoy; Mahshid, Sahar Sadat; Aldridge, Peter M; Sargent, Edward H; Kelley, Shana O

    2016-04-20

    Image-reversal soft lithography enables the straightforward fabrication of high-performance biosensors without requiringhigh-resolution photolitography. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Performance evaluation of a parallel-hole collimated detector module for animal SPECT imaging

    Institute of Scientific and Technical Information of China (English)

    HUANG Xian-Chao; WANG Ying-Jie; WEI Long; SHAN Bao-Ci; WANG Bao-Yi; ZHANG Zhi-Ming; LI Dao-Wu; TANG Hao-Hui; LI Ting; LIAO Yan-Fei; LIU Jun-Hui; WANG Pei-Lin; CHEN Yan

    2011-01-01

    We have built and investigated a detector module for animal SPECT imaging,especially for use in large field of view (FOV) conditions.The module consists of a PMT-based detector and a parallel-hole collimator with an effective area of 80 mm × 80 mm.The detector is composed of a NaI scintillation crystal array coupled to four H8500 position sensitive photomultiplier tubes (PS-PMT).The intrinsic energy resolution of the detector is 11.5% at 140 keV on average.The planar spatial resolution of the module changes from 2.2 mm to 5.1 mm at different source-to-collimator distances with an unchanged sensitivity of about 34cps/MBq.Additionally,the SPECT Micro Deluxe Phantom imaging was performed with a radius of rotation (ROR)of 40 mm.Using the FBP reconstruction algorithm,a high performance image was obtained,indicating the feasibility of this detector module.

  19. 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 (...

  20. A silicon strip detector coupled to the RX64 ASIC for X-ray diagnostic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Baldazzi, G.; Bollini, D.; Cabal Rodriguez, A.E.; Dabrowski, W.; Diaz Garcia, A.; Gambaccini, M.; Giubellino, P.; Gombia, M.; Grybos, P.; Idzik, M.; Marzari-Chiesa, A.; Montano, L.M.; Prino, F. E-mail: prino@to.infn.it; Ramello, L.; Sitta, M.; Swientek, K.; Taibi, A.; Tuffanelli, A.; Wheadon, R.; Wiacek, P

    2003-11-21

    First results from a silicon microstrip detector with 100 {mu}m pitch coupled to the RX64 ASIC are presented. The system is capable of single photon counting in digital X-ray imaging, with possible applications to dual energy mammography and angiography. The main features of the detecting system are low noise, good spatial resolution and high counting rate capability. The energy resolution and the conversion efficiency of the system are discussed, based on results obtained with fluorescence X-ray sources and quasi-monochromatic X-ray beams in the 8-36 keV energy range, with strips being either orthogonal or parallel to the incoming X-rays. We present also preliminary imaging results obtained with a plexiglass phantom with tiny cylindrical cavities filled with iodate solution, simulating patient vessels; in this case the X-ray beam has two components, respectively below and above the iodine K-edge at 33.17 keV.

  1. Linear modeling of single-shot dual-energy x-ray imaging using a sandwich detector

    Science.gov (United States)

    Kim, J.; Kim, D. W.; Kim, S. H.; Yun, S.; Youn, H.; Jeon, H.; Kim, H. K.

    2017-01-01

    For single-shot dual-energy (DE) imaging, a sandwich detector typically consists of a thin front detector and a thick rear detector. Therefore, the spatial-resolution characteristics of the two detectors are different, and as a result, weighted subtraction of the corresponding two images gives rise to edge-enhancement characteristics in the resulting DE images. This is a unique characteristic of single-shot DE imaging compared to the conventional dual-shot DE imaging which uses the same detector to acquire low- and high-energy images. Using a linear-systems theory, in this paper, we show that the modulation-transfer function (MTF) of a sandwich detector is a weighted average of contributions from each MTF characteristic of two detector layers forming the sandwich detector. The MTF results obtained using the developed model are validated with those measured directly from single-shot DE images for an edge-knife phantom. Weighting larger than at least 0.5 in DE reconstruction gives an enhancement in DE MTF at mid and high spatial frequencies compared to the MTFs obtained from each detector layer. The behavior of the linear model as a function of weighting factor used for DE reconstruction is discussed in comparisons with numerical simulations.

  2. Conversion of mammographic images to appear with the noise and sharpness characteristics of a different detector and x-ray system

    Energy Technology Data Exchange (ETDEWEB)

    Mackenzie, Alistair; Dance, David R.; Workman, Adam; Yip, Mary; Wells, Kevin; Young, Kenneth C. [National Coordinating Centre for the Physics of Mammography, Royal Surrey County Hospital, Guildford, GU2 7XX, United Kingdom and Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Northern Ireland Regional Medical Physics Service, Forster Green Hospital, Belfast, BT8 4HD (United Kingdom); Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Centre for Vision, Speech and Signal Processing, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH (United Kingdom); National Coordinating Centre for the Physics of Mammography, Royal Surrey County Hospital, Guildford, GU2 7XX, United Kingdom and Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom)

    2012-05-15

    Purpose: Undertaking observer studies to compare imaging technology using clinical radiological images is challenging due to patient variability. To achieve a significant result, a large number of patients would be required to compare cancer detection rates for different image detectors and systems. The aim of this work was to create a methodology where only one set of images is collected on one particular imaging system. These images are then converted to appear as if they had been acquired on a different detector and x-ray system. Therefore, the effect of a wide range of digital detectors on cancer detection or diagnosis can be examined without the need for multiple patient exposures. Methods: Three detectors and x-ray systems [Hologic Selenia (ASE), GE Essential (CSI), Carestream CR (CR)] were characterized in terms of signal transfer properties, noise power spectra (NPS), modulation transfer function, and grid properties. The contributions of the three noise sources (electronic, quantum, and structure noise) to the NPS were calculated by fitting a quadratic polynomial at each spatial frequency of the NPS against air kerma. A methodology was developed to degrade the images to have the characteristics of a different (target) imaging system. The simulated images were created by first linearizing the original images such that the pixel values were equivalent to the air kerma incident at the detector. The linearized image was then blurred to match the sharpness characteristics of the target detector. Noise was then added to the blurred image to correct for differences between the detectors and any required change in dose. The electronic, quantum, and structure noise were added appropriate to the air kerma selected for the simulated image and thus ensuring that the noise in the simulated image had the same magnitude and correlation as the target image. A correction was also made for differences in primary grid transmission, scatter, and veiling glare. The method was

  3. ATLAS Transition Radiation Tracker (TRT): Straw Tube Gaseous Detectors at High Rates

    CERN Document Server

    Vogel, A; The ATLAS collaboration

    2013-01-01

    The ATLAS Transition Radiation Tracker (TRT) is the outermost of the three tracking subsystems of the ATLAS Inner Detector. The ATLAS detector is located at LHC/CERN. We report on how these gaseous detectors (“straw tubes”) are performing during the ATLAS 2011 and 2012 runs where the TRT experiences higher rates than previously encountered. The TRT contains ~300000 thin-walled proportional-mode drift tubes providing on average 30 two-dimensional space points with ~130 µm resolution for charged particle tracks with |η| 0.5 GeV. Along with continuous tracking, the TRT provides electron identification capability through the detection of transition radiation X-ray photons. During the ATLAS 2012 proton-proton data runs, the TRT is operating successfully while being subjected to the highest rates of incident particles ever experienced by a large scale gaseous tracking system. In the second half of 2012, the TRT has collected data in an environment with instantaneous proton-proton luminosity of ~0.8 × 10³�...

  4. ATLAS Transition Radiation Tracker (TRT): Straw Tube Gaseous Detectors at High Rates

    CERN Document Server

    Vogel, A; The ATLAS collaboration

    2013-01-01

    The ATLAS Transition Radiation Tracker (TRT) is the outermost of the three tracking subsystems of the ATLAS Inner Detector. The ATLAS detector is located at LHC/CERN. We report on how these gaseous detectors (“straw tubes”) are performing during the ATLAS 2011 and 2012 runs where the TRT experiences higher rates than previously encountered. The TRT contains ~300000 thin-walled proportional-mode drift tubes providing on average 30 two-dimensional space points with ~130 µm resolution for charged particle tracks with |η|  0.5 GeV. Along with continuous tracking, the TRT provides electron identification capability through the detection of transition radiation X-ray photons. During the ATLAS 2012 proton-proton data runs, the TRT is operating successfully while being subjected to the highest rates of incident particles ever experienced by a large scale gaseous tracking system. As of the submission date of this abstract, the TRT has collected data in an environment with instantaneous proton-proton luminosi...

  5. DEVELOPMENT OF A HIGH RATE HIGH RESOLUTION DETECTOR FOR EXAFS EXPERIMENTS.

    Energy Technology Data Exchange (ETDEWEB)

    DE GERONIMO,G.; O CONNOR,P.; BEUTTENMULLER,R.H.; LI,Z.; KUCZEWSKI,A.J.; SIDDONS,D.P.

    2002-11-10

    A new detector for EXAFS experiments is being developed. It is based on a multi-element Si sensor and dedicated readout ASICs. The sensor is composed of 384 pixels, each having 1 mm{sup 2} area, arranged in four quadrants of 12 x 8 elements, and wire-bonded to 32-channel front-end ASICs. Each channel implements low noise preamplification with self-adaptive continuous reset, high order shaper, band-gap referenced baseline stabilizer, one threshold comparator and two DAC adjustable window comparators, each followed by a 24-bit counter. Fabricated in 0.35{micro}m CMOS dissipates about 8mW per channel. First measurements show at room temperature a resolution of 14 rms electrons without the detector and of 40 rms electrons (340eV) with the detector connected and biased. Cooling at -35C a FWHM of 205eV (167eV from electronics) was measured at the Mn-K{alpha} line. A resolution of about 300eV was measured for rates approaching 100kcps/cm{sup 2} per channel, corresponding to an overall rate in excess of 10MHz/cm{sup 2}. A channel-to-channel threshold dispersion after DACs adjustment of 2.5 rms electrons was also measured.

  6. High-resolution texture imaging with hard synchrotron radiation in the moving area detector technique

    CERN Document Server

    Wcislak, L; Klein, H; Garbe, U; Schneider, J R

    2003-01-01

    The orientation distribution of crystallites in polycrystalline materials (called texture) is usually measured by polycrystal X-ray diffraction by 'step-scanning' the sample in angular intervals in the order of 1 deg. This technique is not suited to fully exploit the low angular divergence of hard synchrotron radiation in the order of 'milliradian'. Hence, step-scanning was replaced by a continuous 'sweeping' technique using a continuously shifted area detector. In order to avoid overlapping from different reflections (hkl) a Bragg-angle slit was introduced. The 'moving-detector' technique can be applied to obtain images of orientation as well as of location distributions of crystallites in polycrystalline samples. It is suitable for imaging continuous 'orientation density' distribution functions as well as of 'grain-resolved' textures. The excellent features of high-energy synchrotron radiation combined with the moving area detector technique will be illustrated with several examples including very sharp def...

  7. Laboratory coded aperture imaging experiments: radial hole coded masks and depth-sensitive CZT detectors

    CERN Document Server

    Hong, J; Zhang, M; Bellm, E C; Yousef, A; Noss, J; Grindlay, J E; Narita, T

    2004-01-01

    The proposed black-hole finder mission EXIST will consist of multiple wide-field hard X-ray coded-aperture telescopes. The high science goals set for the mission require innovations in telescope design. In particular, wide energy band coverage and fine angular resolution require relatively thick coded masks and thick detectors compared to their pixel size, which may introduce mask self-collimation and depth-induced image blurring with conventional design approaches. Previously we proposed relatively simple solutions to these potential problems: radial hole for mask selfcollimation and cathode depth sensing detector for image blurring. We have now performed laboratory experiments to explore the potential of these two techniques. The experimental results show that the radial hole mask greatly alleviates mask self-collimation and a ~1 mm resolution depth-sensitive detector scheme can be relatively easily achieved for the large scale required for EXIST.

  8. X-ray imaging with photon counting hybrid semiconductor pixel detectors

    CERN Document Server

    Manolopoulos, S; Campbell, M; Snoeys, W; Heijne, Erik H M; Pernigotti, E; Raine, C; Smith, K; Watt, J; O'Shea, V; Ludwig, J; Schwarz, C

    1999-01-01

    Semiconductor pixel detectors, originally developed for particle physics experiments, have been studied as X-ray imaging devices. The performance of devices using the OMEGA 3 read-out chip bump-bonded to pixellated silicon semiconductor detectors is characterised in terms of their signal-to-noise ratio when exposed to 60 kVp X-rays. Although parts of the devices achieve values of this ratio compatible with the noise being photon statistics limited, this is not found to hold for the whole pixel matrix, resulting in the global signal-to-noise ratio being compromised. First results are presented of X-ray images taken with a gallium arsenide pixel detector bump-bonded to a new read-out chip, (MEDIPIX), which is a single photon counting read-out chip incorporating a 15-bit counter in every pixel. (author)

  9. X-ray imaging with photon counting hybrid semiconductor pixel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Manolopoulos, S.; Bates, R.; Campbell, M.; Snoeys, W.; Heijne, E.; Pernigotti, E.; Raine, C.; Smith, K. E-mail: k.smith@physics.gla.ac.uk; Watt, J.; O' Shea, V.; Ludwig, J.; Schwarz, C

    1999-09-11

    Semiconductor pixel detectors, originally developed for particle physics experiments, have been studied as X-ray imaging devices. The performance of devices using the {omega}3 read-out chip bump-bonded to pixellated silicon semiconductor detectors is characterised in terms of their signal-to-noise ratio when exposed to 60 kVp X-rays. Although parts of the devices achieve values of this ratio compatible with the noise being photon statistics limited, this is not found to hold for the whole pixel matrix, resulting in the global signal-to-noise ratio being compromised. First results are presented of X-ray images taken with a gallium arsenide pixel detector bump-bonded to a new read-out chip, (MEDIPIX), which is a single photon counting read-out chip incorporating a 15-bit counter in every pixel. (author)

  10. Design and optimization of resistive anode for a two-dimensional imaging GEM detector

    Science.gov (United States)

    Ju, Xu-Dong; Dong, Ming-Yi; Zhao, Yi-Chen; Zhou, Chuan-Xing; Qun, Ou-Yang

    2016-08-01

    A resistive anode for two-dimensional imaging detectors, which consists of a series of high resistivity pads surrounded by low resistivity strips, can provide good spatial resolution while reducing the number of electronics channels required. The optimization of this kind of anode has been studied by both numerical simulations and experimental tests. It is found that to obtain good detector performance, the resistance ratio of the pads to the strips should be larger than 5, the nonuniformity of the pad surface resistivity should be less than 20%, a smaller pad width leads to a smaller spatial resolution, and when the pad width is 6 mm, the spatial resolution (σ) can reach about 105 μm. Based on the study results, a 2-D GEM detector prototype with optimized resistive anode is constructed and a good imaging performance is achieved. Supported by National Natural Science Foundation of China (11375219) and CAS Center for Excellence in Particle Physics (CCEPP)

  11. Development of a detector based on Silicon Drift Detectors for gamma-ray spectroscopy and imaging applications

    Science.gov (United States)

    Busca, P.; Butt, A. D.; Fiorini, C.; Marone, A.; Occhipinti, M.; Peloso, R.; Quaglia, R.; Bombelli, L.; Giacomini, G.; Piemonte, C.; Camera, F.; Giaz, A.; Million, B.; Nelms, N.; Shortt, B.

    2014-05-01

    This work deals with the development of a new gamma detector based on Silicon Drift Detectors (SDDs) to readout large LaBr3:Ce scintillators for gamma-ray spectroscopy and imaging applications. The research is supported by the European Space Agency through the Technology Research Programme (TRP) and by Istituto Nazionale di Fisica Nucleare (INFN) within the Gamma project. The SDDs, produced at Fondazione Bruno Kessler (FBK) semiconductor laboratories, are designed as monolithic arrays of 3 × 3 units, each one of an active area of 8 mm × 8 mm (overall area of 26 mm × 26 mm). The readout electronics and the architecture of the camera are briefly described and then first experimental results coupling the SDD array with a 1'' × 1'' LaBr3:Ce scintillator are reported. An energy resolution of 3% FWHM at 662 keV has been measured at -20°C, better than coupling the same scintillator with a photomultiplier tube. The same scintillator is also used to evaluate position sensitivity with a 1 mm collimated Cs-137 source. The main difficulty in determining the position of the gamma-ray interaction in the crystal is associated to the high thickness/diameter ratio of the crystal (1:1) and the use of reflectors on all lateral and top sides the crystal. This last choice enhances energy resolution but makes imaging capability more challenging because light is spread over all photodetectors. Preliminary results show that the camera is able to detect shifts in the measured signals, when the source is moved with steps of 5 mm. A modified version of the centroid method is finally implemented to evaluate the imaging capability of the system.

  12. Wideband Optical Detector of Ultrasound for Medical Imaging Applications

    Science.gov (United States)

    Rosenthal, Amir; Kellnberger, Stephan; Omar, Murad; Razansky, Daniel; Ntziachristos, Vasilis

    2014-01-01

    Optical sensors of ultrasound are a promising alternative to piezoelectric techniques, as has been recently demonstrated in the field of optoacoustic imaging. In medical applications, one of the major limitations of optical sensing technology is its susceptibility to environmental conditions, e.g. changes in pressure and temperature, which may saturate the detection. Additionally, the clinical environment often imposes stringent limits on the size and robustness of the sensor. In this work, the combination of pulse interferometry and fiber-based optical sensing is demonstrated for ultrasound detection. Pulse interferometry enables robust performance of the readout system in the presence of rapid variations in the environmental conditions, whereas the use of all-fiber technology leads to a mechanically flexible sensing element compatible with highly demanding medical applications such as intravascular imaging. In order to achieve a short sensor length, a pi-phase-shifted fiber Bragg grating is used, which acts as a resonator trapping light over an effective length of 350 µm. To enable high bandwidth, the sensor is used for sideway detection of ultrasound, which is highly beneficial in circumferential imaging geometries such as intravascular imaging. An optoacoustic imaging setup is used to determine the response of the sensor for acoustic point sources at different positions. PMID:24895083

  13. A Multi-Contact, Low Capacitance HPGe Detector for High Rate Gamma Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cox, Christopher [XIA LLC, Hayward, CA (United States)

    2014-12-04

    The detection, identification and non-destructive assay of special nuclear materials and nuclear fission by-products are critically important activities in support of nuclear non-proliferation programs. Both national and international nuclear safeguard agencies recognize that current accounting methods for spent nuclear fuel are inadequate from a safeguards perspective. Radiation detection and analysis by gamma-ray spectroscopy is a key tool in this field, but no instrument exists that can deliver the required performance (energy resolution and detection sensitivity) in the presence of very high background count rates encountered in the nuclear safeguards arena. The work of this project addresses this critical need by developing a unique gamma-ray detector based on high purity germanium that has the previously unachievable property of operating in the 1 million counts-per-second range while achieving state-of-the-art energy resolution necessary to identify and analyze the isotopes of interest. The technical approach was to design and fabricate a germanium detector with multiple segmented electrodes coupled to multi-channel high rate spectroscopy electronics. Dividing the germanium detector’s signal electrode into smaller sections offers two advantages; firstly, the energy resolution of the detector is potentially improved, and secondly, the detector is able to operate at higher count rates. The design challenges included the following; determining the optimum electrode configuration to meet the stringent energy resolution and count rate requirements; determining the electronic noise (and therefore energy resolution) of the completed system after multiple signals are recombined; designing the germanium crystal housing and vacuum cryostat; and customizing electronics to perform the signal recombination function in real time. In this phase I work, commercial off-the-shelf electrostatic modeling software was used to develop the segmented germanium crystal geometry

  14. A comparison of CsI:Tl and GOS in a scintillator-CCD detector for nuclear medicine imaging

    Science.gov (United States)

    Bugby, S. L.; Jambi, L. K.; Lees, J. E.

    2016-09-01

    A number of portable gamma cameras for medical imaging use scintillator-CCD based detectors. This paper compares the performance of a scintillator-CCD based portable gamma camera with either a columnar CsI:Tl or a pixelated GOS scintillator installed. The CsI:Tl scintillator has a sensitivity of 40% at 140.5 keV compared to 54% with the GOS scintillator. The intrinsic spatial resolution of the pixelated GOS detector was 1.09 mm, over 4 times poorer than for CsI:Tl. Count rate capability was also found to be significantly lower when the GOS scintillator was used. The uniformity was comparable for both scintillators.

  15. A prototype High Purity Germanium detector for high resolution gamma-ray spectroscopy at high count rates

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.J., E-mail: rjcooper@lbl.gov [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Amman, M.; Luke, P.N. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Vetter, K. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Nuclear Engineering, University of California, Berkeley, CA 94720 (United States)

    2015-09-21

    Where energy resolution is paramount, High Purity Germanium (HPGe) detectors continue to provide the optimum solution for gamma-ray detection and spectroscopy. Conventional large-volume HPGe detectors are typically limited to count rates on the order of ten thousand counts per second, however, limiting their effectiveness for high count rate applications. To address this limitation, we have developed a novel prototype HPGe detector designed to be capable of achieving fine energy resolution and high event throughput at count rates in excess of one million counts per second. We report here on the concept, design, and initial performance of the first prototype device.

  16. Edgeless silicon sensors for Medipix-based large-area X-ray imaging detectors

    NARCIS (Netherlands)

    Bosma, M.J.; Visser, J.; Evrard, O.; de Moor, P.; de Munck, K.; Sabuncuoglu Tezcan, D.; Koffeman, E.N.

    2011-01-01

    Some X-ray imaging applications demand sensitive areas exceeding the active area of a single sensor. This requires a seamless tessellation of multiple detector modules with edgeless sensors. Our research is aimed at minimising the insensitive periphery that isolates the active area from the edge. Re

  17. Organic non-volatile resistive photo-switches for flexible image detector arrays.

    Science.gov (United States)

    Nau, Sebastian; Wolf, Christoph; Sax, Stefan; List-Kratochvil, Emil J W

    2015-02-01

    A unique implementation of an organic image detector using resistive photo-switchable pixels is presented. This resistive photo-switch comprises the vertical integration of an organic photodiode and an organic resistive switching memory element. The photodiodes act as a photosensitive element while the resistive switching elements simultaneously store the detected light information.

  18. Table-top phase-contrast imaging employing photon-counting detectors towards mammographic applications

    Science.gov (United States)

    Palma, K. D.; Pichotka, M.; Hasn, S.; Granja, C.

    2017-02-01

    In mammography the difficult task to detect microcalcifications (≈ 100 μm) and low contrast structures in the breast has been a topic of interest from its beginnings. The possibility to improve the image quality requires the effort to employ novel X-ray imaging techniques, such as phase-contrast, and high resolution detectors. Phase-contrast techniques are promising tools for medical diagnosis because they provide additional and complementary information to traditional absorption-based X-ray imaging methods. In this work a Hamamatsu microfocus X-ray source with tungsten anode and a photon counting detector (Timepix operated in Medipix mode) was used. A significant improvement in the detection of phase-effects using Medipix detector was observed in comparison to an standard flat-panel detector. An optimization of geometrical parameters reveals the dependency on the X-ray propagation path and the small angle deviation. The quantification of these effects was achieved taking into account the image noise, contrast, spatial resolution of the phase-enhancement, absorbed dose, and energy dependence.

  19. Image processing analysis of nuclear track parameters for CR-39 detector irradiated by thermal neutron

    Science.gov (United States)

    Al-Jobouri, Hussain A.; Rajab, Mustafa Y.

    2016-03-01

    CR-39 detector which covered with boric acid (H3Bo3) pellet was irradiated by thermal neutrons from (241Am - 9Be) source with activity 12Ci and neutron flux 105 n. cm-2. s-1. The irradiation times -TD for detector were 4h, 8h, 16h and 24h. Chemical etching solution for detector was sodium hydroxide NaOH, 6.25N with 45 min etching time and 60 C˚ temperature. Images of CR-39 detector after chemical etching were taken from digital camera which connected from optical microscope. MATLAB software version 7.0 was used to image processing. The outputs of image processing of MATLAB software were analyzed and found the following relationships: (a) The irradiation time -TD has behavior linear relationships with following nuclear track parameters: i) total track number - NT ii) maximum track number - MRD (relative to track diameter - DT) at response region range 2.5 µm to 4 µm iii) maximum track number - MD (without depending on track diameter - DT). (b) The irradiation time -TD has behavior logarithmic relationship with maximum track number - MA (without depending on track area - AT). The image processing technique principally track diameter - DT can be take into account to classification of α-particle emitters, In addition to the contribution of these technique in preparation of nano- filters and nano-membrane in nanotechnology fields.

  20. Anti-scatter grid artifact elimination for high resolution x-ray imaging CMOS detectors

    Science.gov (United States)

    Rana, R.; Singh, V.; Jain, A.; Bednarek, D. R.; Rudin, S.

    2015-03-01

    Higher resolution in dynamic radiological imaging such as angiography is increasingly being demanded by clinicians; however, when standard anti-scatter grids are used with such new high resolution detectors, grid-line artifacts become more apparent resulting in increased structured noise that may overcome the contrast signal improvement benefits of the scatter-reducing grid. Although grid-lines may in theory be eliminated by dividing the image of a patient taken with the grid by a flat-field image taken with the grid obtained prior to the clinical image, unless the remaining additive scatter contribution is subtracted in real-time from the dynamic clinical image sequence before the division by the reference image, severe grid-line artifacts may remain. To investigate grid-line elimination, a stationary Smit Röntgen X-ray grid (line density: 70 lines/cm, grid ratio 13:1) was used with both a 75 micron-pixel CMOS detector and a standard 194 micron-pixel flat panel detector (FPD) to image an artery block insert placed in a modified uniform frontal head phantom for a 20 x 20cm FOV (approximately). Contrast and contrast-to-noise ratio (CNR) were measured with and without scatter subtraction prior to grid-line correction. The fixed pattern noise caused by the grid was substantially higher for the CMOS detector compared to the FPD and caused a severe reduction of CNR. However, when the scatter subtraction corrective method was used, the removal of the fixed pattern noise (grid artifacts) became evident resulting in images with improved CNR.

  1. HEPS-BPIX, a single photon counting pixel detector with a high frame rate for the HEPS project

    Science.gov (United States)

    Wei, Wei; Zhang, Jie; Ning, Zhe; Lu, Yunpeng; Fan, Lei; Li, Huaishen; Jiang, Xiaoshan; Lan, Allan K.; Ouyang, Qun; Wang, Zheng; Zhu, Kejun; Chen, Yuanbo; Liu, Peng

    2016-11-01

    China's next generation light source, named the High Energy Photon Source (HEPS), is currently under construction. HEPS-BPIX (HEPS-Beijing PIXel) is a dedicated pixel readout chip that operates in single photon counting mode for X-ray applications in HEPS. Designed using CMOS 0.13 μm technology, the chip contains a matrix of 104×72 pixels. Each pixel measures 150 μm×150 μm and has a counting depth of 20 bits. A bump-bonded prototyping detector module with a 300-μm thick silicon sensor was tested in the beamline of Beijing Synchrotron Radiation Facility. A fast stream of X-ray images was demonstrated, and a frame rate of 1.2 kHz was proven, with a negligible dead time. The test results showed an equivalent noise charge of 115 e- rms after bump bonding and a threshold dispersion of 55 e- rms after calibration.

  2. Investigation of photon counting pixel detectors for X-ray spectroscopy and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Talla, Patrick Takoukam

    2011-04-07

    The Medipix2 and Medipix3 detectors are hybrid pixelated photon counting detectors with a pixel pitch of 55 {mu}m. The sensor material used in this thesis was silicon. Because of their small pixel size they suffer from charge sharing i.e. an incoming photon can be registered by more than one pixel. In order to correct for charge sharing due to lateral diffusion of charge carriers, the Medipix3 detector was developed: with its Charge Summing Mode, the charge collected in a cluster of 2 x 2 pixel is added up and attributed to only one pixel whose counter is incremented. The adjustable threshold of the detectors allows to count the photons and to gain information on their energy. The main purposes of the thesis are to investigate spectral and imaging properties of pixelated photon counting detectors from the Medipix family such as Medipix2 and Medipix3. The investigations are based on simulations and measurements. In order to investigate the spectral properties of the detectors measurements were performed using fluorescence lines of materials such as molybdenum, silver but also some radioactive sources such as Am-241 or Cd-109. From the measured data, parameters like the threshold dispersion and the gain variation from pixel-to-pixel were extracted and used as input in the Monte Carlo code ROSI to model the responses of the detector to monoenergetic photons. The measured data are well described by the simulations for Medipix2 and for Medipix3 operating in Charge Summing Mode. Due to charge sharing and due to the energy dependence of attenuation processes in silicon and to Compton scattering the incoming and the measured spectrum differ substantially from each other. Since the responses to monoenergetic photons are known, a deconvolution was performed to determine the true incoming spectrum. Several direct and iterative methods were successfully applied on measured and simulated data of an X-ray tube and radioactive sources. The knowledge of the X-ray spectrum is

  3. Multipixel characterization of imaging CZT detectors for hard x-ray imaging and spectroscopy

    Science.gov (United States)

    Vadawale, Santosh V.; Hong, Jae Sub; Grindlay, Jonathan E.; Williams, Peter; Zhang, Minhua; Bellm, Eric C.; Narita, Tomohiko; Craig, William W.; Parker, Bradford H.; Stahle, Carl M.; Yan, Feng

    2004-10-01

    We report our in-depth study of Cd-Zn-Te (CZT) crystals to determine an optimum pixel and guard band configuration for Hard X-ray imaging and spectroscopy. We tested 20x20x5mm crystals with 8x8 pixels on a 2.46mm pitch. We have studied different types of cathode / anode contacts and different pixel pad sizes. We present the measurements of leakage current as well as spectral response for each pixel. Our I-V measurement setup is custom designed to allow automated measurements of the I-V curves sequentially for all 64 pixels, whereas the radiation properties measurement setup allows for interchangeable crystals with the same XAIM3.2 ASIC readout from IDEAS. We have tested multiple crystals of each type, and each crystal in different positions to measure the variation between individual crystals and variation among the ASIC channels. We also compare the same crystals with and without a grounded guard band deposited on the crystal side walls vs. a floating guard band and compare results to simulations. This study was carried out to find the optimum CZT crystal configuration for prototype detectors for the proposed Black-Hole Finder mission, EXIST.

  4. Low energy electron microscopy imaging using Medipix2 detector

    NARCIS (Netherlands)

    Sikharulidze, I.; Gastel, van R.; Schramm, S.; Abrahams, J.P.; Poelsema, B.; Tromp, R.M.; Molen, van der S.J.

    2011-01-01

    Low Energy Electron Microscopy (LEEM) and Photo-Emission Electron Microscopy (PEEM) predominantly use a combination of microchannel plate (MCP), phosphor screen and optical camera to record images formed by 10–20 keV electrons. We have tested the performance of a LEEM/PEEM instrument with a Medipix2

  5. Advanced data readout technique for Multianode Position Sensitive Photomultiplier Tube applicable in radiation imaging detectors

    Science.gov (United States)

    Popov, V.

    2011-01-01

    Most of the best performing PSPMT tubes from Hamamatsu and Burle are designed with a pad-matrix anode layout. However, for obtaining a high resolution, a small-sized anode photomultiplier tubes are preferable; these tubes may have 64, 256 or 1024 anodes per tube. If the tubes are used in array to get a larger area detector, the number of analog channels may range from hundreds to thousands. Multichannel analog readout requires special electronics ICs, ASICs etc., which are attached to multichannel DAQ system. As a result, the data file and data processing time will be increased. Therefore, this readout could not be performed in a small project. Usually, most of radiation imaging applications allow the use of analog data processing in front-end electronics, significantly reducing the number of the detector's output lines to data acquisition without reducing the image quality. The idea of pad-matrix decoupling circuit with gain correction was invented and intensively tested in JLab. Several versions of PSPMT readout electronics were produced and studied. All developments were done and optimized specifically for radiation imaging projects. They covered high resolution SPECT, high speed PET, fast neutron imaging, and single tube and multi tube array systems. This paper presents and discusses the summary of the observed results in readout electronics evaluation with different PSPMTs and radiation imaging systems, as well as the advantages and limitations of the developed approach to radiation imaging detectors readout.

  6. Imaging of Ra-223 with a small-pixel CdTe detector

    Science.gov (United States)

    Scuffham, J. W.; Pani, S.; Seller, P.; Sellin, P. J.; Veale, M. C.; Wilson, M. D.; Cernik, R. J.

    2015-01-01

    Ra-223 Dichloride (Xofigo™) is a promising new radiopharmaceutical offering survival benefit and palliation of painful bone metastases in patients with hormone-refractory prostate cancer [1]. The response to radionuclide therapy and toxicity are directly linked to the absorbed radiation doses to the tumour and organs at risk respectively. Accurate dosimetry necessitates quantitative imaging of the biodistribution and kinetics of the radiopharmaceutical. Although primarily an alpha-emitter, Ra-223 also has some low-abundance X-ray and gamma emissions, which enable imaging of the biodistribution in the patient. However, the low spectral resolution of conventional gamma camera detectors makes in-vivo imaging of Ra-223 challenging. In this work, we present spectra and image data of anthropomorphic phantoms containing Ra-223 acquired with a small-pixel CdTe detector (HEXITEC) [2] with a pinhole collimator. Comparison is made with similar data acquired using a clinical gamma camera. The results demonstrate the advantages of the solid state detector in terms of scatter rejection and quantitative accuracy of the images. However, optimised collimation is needed in order for the sensitivity to rival current clinical systems. As different dosage levels and administration regimens for this drug are explored in current clinical trials, there is a clear need to develop improved imaging technologies that will enable personalised treatments to be designed for patients.

  7. CdTe and CdZnTe gamma ray detectors for medical and industrial imaging systems

    CERN Document Server

    Eisen, Y; Mardor, I

    1999-01-01

    CdTe and CdZnTe X-ray and gamma ray detectors in the form of single elements or as segmented monolithic detectors have been shown to be useful in medical and industrial imaging systems. These detectors possess inherently better energy resolution than scintillators coupled to either photodiodes or photomultipliers, and together with application specific integrated circuits they lead to compact imaging systems of enhanced spatial resolution and better contrast resolution. Photopeak efficiencies of these detectors is greatly affected by a relatively low hole mobility-lifetime product. Utilizing these detectors as highly efficient good spectrometers, demands use of techniques to improve their charge collection properties, i.e., correct for variations in charge losses at different depths of interaction in the detector. The corrections for the large hole trapping are made either by applying electronic techniques or by fabricating detector or electrical contacts configurations which differ from the commonly used pla...

  8. Imaging detector development for nuclear astrophysics using pixelated CdTe

    Science.gov (United States)

    Álvarez, J. M.; Gálvez, J. L.; Hernanz, M.; Isern, J.; Llopis, M.; Lozano, M.; Pellegrini, G.; Chmeissani, M.

    2010-11-01

    The concept of focusing telescopes in the energy range of lines of astrophysical interest (i.e., of energies around 1 MeV) should allow to reach unprecedented sensitivities, essential to perform detailed studies of cosmic explosions and cosmic accelerators. Our research and development activities aim to study a detector suited for the focal plane of a γ-ray telescope mission. A CdTe/CdZnTe detector operating at room temperature, that combines high detection efficiency with good spatial and spectral resolution is being studied in recent years as a focal plane detector, with the interesting option of also operating as a Compton telescope monitor. We present the current status of the design and development of a γ-ray imaging spectrometer in the MeV range, for nuclear astrophysics, consisting of a stack of CdTe pixel detectors with increasing thicknesses. We have developed an initial prototype based on CdTe ohmic detector. The detector has 11×11 pixels, with a pixel pitch of 1 mm and a thickness of 2 mm. Each pixel is stud bonded to a fanout board and routed to an front end ASIC to measure pulse height and rise time information for each incident γ-ray photon. First measurements of a 133Ba and 241Am source are reported here.

  9. Imaging detector development for nuclear astrophysics using pixelated CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, J.M., E-mail: alvarez@ieec.uab.e [Institut de Ciencies de l' Espai (CSIC-IEEC), Campus UAB, E-08193 Barcelona (Spain); Galvez, J.L.; Hernanz, M.; Isern, J.; Llopis, M. [Institut de Ciencies de l' Espai (CSIC-IEEC), Campus UAB, E-08193 Barcelona (Spain); Lozano, M.; Pellegrini, G. [Centro Nacional de Microelectronica - IMB-CNM (CSIC), Campus UAB, E-08193 Barcelona (Spain); Chmeissani, M. [Institut de Fisica d' Altes Energies (IFAE), Campus UAB, E-08193 Barcelona (Spain)

    2010-11-01

    The concept of focusing telescopes in the energy range of lines of astrophysical interest (i.e., of energies around 1 MeV) should allow to reach unprecedented sensitivities, essential to perform detailed studies of cosmic explosions and cosmic accelerators. Our research and development activities aim to study a detector suited for the focal plane of a {gamma}-ray telescope mission. A CdTe/CdZnTe detector operating at room temperature, that combines high detection efficiency with good spatial and spectral resolution is being studied in recent years as a focal plane detector, with the interesting option of also operating as a Compton telescope monitor. We present the current status of the design and development of a {gamma}-ray imaging spectrometer in the MeV range, for nuclear astrophysics, consisting of a stack of CdTe pixel detectors with increasing thicknesses. We have developed an initial prototype based on CdTe ohmic detector. The detector has 11x11 pixels, with a pixel pitch of 1 mm and a thickness of 2 mm. Each pixel is stud bonded to a fanout board and routed to an front end ASIC to measure pulse height and rise time information for each incident {gamma}-ray photon. First measurements of a {sup 133}Ba and {sup 241}Am source are reported here.

  10. Compton imaging with a highly-segmented, position-sensitive HPGe detector

    Science.gov (United States)

    Steinbach, T.; Hirsch, R.; Reiter, P.; Birkenbach, B.; Bruyneel, B.; Eberth, J.; Gernhäuser, R.; Hess, H.; Lewandowski, L.; Maier, L.; Schlarb, M.; Weiler, B.; Winkel, M.

    2017-02-01

    A Compton camera based on a highly-segmented high-purity germanium (HPGe) detector and a double-sided silicon-strip detector (DSSD) was developed, tested, and put into operation; the origin of γ radiation was determined successfully. The Compton camera is operated in two different modes. Coincidences from Compton-scattered γ-ray events between DSSD and HPGe detector allow for best angular resolution; while the high-efficiency mode takes advantage of the position sensitivity of the highly-segmented HPGe detector. In this mode the setup is sensitive to the whole 4π solid angle. The interaction-point positions in the 36-fold segmented large-volume HPGe detector are determined by pulse-shape analysis (PSA) of all HPGe detector signals. Imaging algorithms were developed for each mode and successfully implemented. The angular resolution sensitively depends on parameters such as geometry, selected multiplicity and interaction-point distances. Best results were obtained taking into account the crosstalk properties, the time alignment of the signals and the distance metric for the PSA for both operation modes. An angular resolution between 13.8° and 19.1°, depending on the minimal interaction-point distance for the high-efficiency mode at an energy of 1275 keV, was achieved. In the coincidence mode, an increased angular resolution of 4.6° was determined for the same γ-ray energy.

  11. Design and development of hard x-ray imaging detector using scintillator and Si photomultiplier

    Science.gov (United States)

    Goyal, S. K.; Naik, Amisha P.; Mithun, N. P. S.; Vadawale, S. V.; Acharya, Y. B.; Patel, A. R.; Ladiya, T.; Devashrayee, Niranjan M.

    2016-07-01

    There are various astrophysical phenomena which are of great importance and interest such as stellar explosions, Gamma ray bursts etc. There is also a growing interest in exploring the celestial sources in hard X-rays. High sensitive instruments are essential to perform the detailed studies of these cosmic accelerators and explosions. Hard X-ray imaging detectors having high absorption efficiency and mm spatial resolution are the key requirements to locate the generation of these astrophysical phenomenon. We hereby present a detector module which consists of a single CsI scintillation detector of size 15 x 15 x 3 mm3. The photon readout is done using an array of Silicon Photomultipliers (SiPMs). SiPM is a new development in the field of photon detection and can be described as 2D array of small (hundreds of μm2) avalanche photodiodes. We have achieved a spatial resolution of 0.5 mm with our initial setup. By using the array of these detector modules, we can build the detector with a large sensitive area with a very high spatial resolution. This paper presents the experimental details for single detector module using CsI (Tl) scintillator and SiPM and also presents the preliminary results of energy and position measurement. The GEANT4 simulation has also been carried out for the same geometry.

  12. Vehicle Detection in Still Images by Using Boosted Local Feature Detector

    Institute of Scientific and Technical Information of China (English)

    Qing LIN; Young-joon HAN; Hern-soo HAHN

    2010-01-01

    Vehicle detection in still images is a comparatively difficult task.This paper presents a method for this task by using boosted local pattem detector constructed from two local features including Haar-like and oriented gradient features.The whole process is composed of three stages.In the first stage,local appearance features of vehicles and non-vehicle objects are extracted.Haar-like and oriented gradient features arc extracted separately in this stage as local features.In the second stage,Adaboost algorithm is used to select the mast discriminative features as weak detectors from the two local feature sets,and a strong local pattern detector is built by the weighted combination of these selected weak detectors.Finally,vehicle detection can be performed in still images by using the boosted strong local feature detector.Experiment results show that the local pattern detectur constructed in this way combines the advantages of Haar-like and oriented gradient features,and can achieve better detection results than the datector by using single Haar-like features.

  13. Feasibility Study of Gas Electron Multiplier Detector as an X-Ray Image Sensor

    CERN Document Server

    Shin, Sukyoung; Lee, Soonhyouk

    2015-01-01

    For its ease manufacturing, flexible geometry, and cheap manufacturing cost, the gas electron multiplier (GEM) detector can be used as an x-ray image sensor. For this purpose, we acquired relative detection efficiencies and suggested a method to increase the detection efficiency in order to study the possibility of GEM detector as an x-ray image sensor. The GEM detector system is composed of GEM foils, the instrument system, the gas system, and the negative power supply. The instrument system consists of the A225 charge sensitive preamp, A206 discriminator, and MCA8000D multichannel analyzer. For the gas system, Argon gas was mixed with CO2 to the ratio of 8:2, and for the negative 2,000 volts, the 3106D power supply was used. The CsI-coated GEM foil was used to increase the detection efficiency. Fe-55 was used as an x-ray source and the relative efficiency was acquired by using the ratio of GEM detector to the CdTe detector. The total count method and the energy spectrum method were used to calculate the rel...

  14. Experimental test of the background rejection, through imaging capability, of a highly segmented AGATA germanium detector

    Energy Technology Data Exchange (ETDEWEB)

    Doncel, M., E-mail: doncel@usal.e [Laboratorio de Radiaciones Ionizantes, Universidad de Salamanca (Spain); Recchia, F. [INFN sezione di Padova, Padova (Italy); Quintana, B. [Laboratorio de Radiaciones Ionizantes, Universidad de Salamanca (Spain); Gadea, A. [IFIC Valencia, Valencia (Spain); INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Farnea, E. [INFN sezione di Padova, Padova (Italy)

    2010-10-21

    The development of highly segmented germanium detectors as well as the algorithms to identify the position of the interaction within the crystal opens the possibility to locate the {gamma}-ray source using Compton imaging algorithms. While the Compton-suppression shield, coupled to the germanium detector in conventional arrays, works also as an active filter against the {gamma} rays originated outside the target, the new generation of position sensitive {gamma}-ray detector arrays has to fully rely on tracking capabilities for this purpose. In specific experimental conditions, as the ones foreseen at radioactive beam facilities, the ability to discriminate background radiation improves the sensitivity of the gamma spectrometer. In this work we present the results of a measurement performed at the Laboratori Nazionali di Legnaro (LNL) aiming the evaluation of the AGATA detector capabilities to discriminate the origin of the {gamma} rays on an event-by-event basis. It will be shown that, exploiting the Compton scattering formula, it is possible to track back {gamma} rays coming from different positions, assigning them to specific emitting locations. These imaging capabilities are quantified for a single crystal AGATA detector.

  15. Imaging, Detection, and Identification Algorithms for Position-Sensitive Gamma-Ray Detectors

    Science.gov (United States)

    Wahl, Christopher G.

    Three-dimensional-position-sensitive semiconductors record both the locations and energies of gamma-ray interactions with high resolution, enabling spectroscopy and imaging of gamma-ray-emitting materials. Imaging enables the detection of point sources of gamma rays in an otherwise extended-source background, even when the background spectrum is unknown and may share the point source's spectrum. The generalized likelihood ratio test (GLRT) and source-intensity test (SIT) are applied to this situation to detect one-or-more unshielded point sources from a library of isotopes in a spectrally unknown or known background when the background intensity varies spatially by a factor of two or less. In addition to estimating the number of sources present, their activities, isotopes, and directions from the detector are estimated. Experimental and some simulated results are presented for a single detector and an 18-detector array of 2 cm by 2 cm by 1.5 cm CdZnTe crystals and compared with the performance of spectral-only detection when the background and source are assumed to be spectrally different. Furthermore, the expected detection performance of the 18-detector array system is investigated statistically using experimental data in the case where the background is distinct spectrally from the point source and the possible source location and isotopic identity are known. Including imaging gave at least 7% higher SNR compared to ignoring the image dimension. Also, imaging methods based on the maximum-likelihood, expectation-maximization method are introduced to determine the spatial distribution of isotopes and to find the activity distributions within targets moving with known motion through a radioactive background. Software has also been developed to support the analysis of the data from 3D-position-sensitive spectroscopic systems, for a range of detector designs and applications. The software design and unique features that allow fast multidimensional data analysis are

  16. Development of a three-layer phoswich alpha–beta–gamma imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya (Japan); Ishibashi, Hiroyuki [Hitachi Chemical, Ibaraki (Japan)

    2015-06-11

    For radiation monitoring at the sites of such nuclear power plant accidents as Fukushima Daiichi, radiation detectors are needed not only for gamma photons but also for alpha and beta particles because some nuclear fission products emit beta particles and gamma photons and some nuclear fuels contain plutonium that emits alpha particles. In some applications, imaging detectors are required to detect the distribution of plutonium particles that emit alpha particles and radiocesium in foods that emits beta particles and gamma photons. To solve these requirements, we developed an imaging detector that can measure the distribution of alpha and beta particles as well as gamma photons. The imaging detector consists of three-layer scintillators optically coupled to each other and to a position sensitive photomultiplier tube (PSPMT). The first layer, which is made of a thin plastic scintillator (decay time: ~5 ns), detects alpha particles. The second layer, which is made of a thin Gd{sub 2}SiO{sub 5} (GSO) scintillator with 1.5 mol% Ce (decay time: 35 ns), detects beta particles. The third layer made of a thin GSO scintillator with 0.4 mol% Ce (decay time: 70 ns) detects gamma photons. Using pulse shape discrimination, the images of these layers can be separated. The position information is calculated by the Anger principle from 8×8 anode signals from the PSPMT. The images for the alpha and beta particles and the gamma photons are individually formed by the pulse shape discriminations for each layer. We detected alpha particle images in the first layer and beta particle images in the second layer. Gamma photon images were detected in the second and third layers. The spatial resolution for the alpha and beta particles was ~1.25 mm FWHM and less than 2 mm FWHM for the gamma photons. We conclude that our developed alpha–beta–gamma imaging detector is promising for imaging applications not only for the environmental monitoring of radionuclides but also for medical and

  17. Imaging properties of small-pixel spectroscopic x-ray detectors based on cadmium telluride sensors.

    Science.gov (United States)

    Koenig, Thomas; Schulze, Julia; Zuber, Marcus; Rink, Kristian; Butzer, Jochen; Hamann, Elias; Cecilia, Angelica; Zwerger, Andreas; Fauler, Alex; Fiederle, Michael; Oelfke, Uwe

    2012-11-07

    Spectroscopic x-ray imaging by means of photon counting detectors has received growing interest during the past years. Critical to the image quality of such devices is their pixel pitch and the sensor material employed. This paper describes the imaging properties of Medipix2 MXR multi-chip assemblies bump bonded to 1 mm thick CdTe sensors. Two systems were investigated with pixel pitches of 110 and 165 μm, which are in the order of the mean free path lengths of the characteristic x-rays produced in their sensors. Peak widths were found to be almost constant across the energy range of 10 to 60 keV, with values of 2.3 and 2.2 keV (FWHM) for the two pixel pitches. The average number of pixels responding to a single incoming photon are about 1.85 and 1.45 at 60 keV, amounting to detective quantum efficiencies of 0.77 and 0.84 at a spatial frequency of zero. Energy selective CT acquisitions are presented, and the two pixel pitches' abilities to discriminate between iodine and gadolinium contrast agents are examined. It is shown that the choice of the pixel pitch translates into a minimum contrast agent concentration for which material discrimination is still possible. We finally investigate saturation effects at high x-ray fluxes and conclude with the finding that higher maximum count rates come at the cost of a reduced energy resolution.

  18. Study of Scintillator thickness optimization of lens-coupled X-ray imaging detectors

    Science.gov (United States)

    Xie, H.; Du, G.; Deng, B.; Chen, R.; Xiao, T.

    2016-03-01

    Lens-coupled X-ray in-direct imaging detectors are very popular for high-resolution X-ray imaging at the third generation synchrotron radiation facilities. This imaging system consists of a scintilator producing a visible-light image of X-ray beam, a microscope objective, a mirror reflecting at 90° and a CCD camera. When the thickness of the scintillator is matched with the numerical aperture (NA) of the microscope objective, the image quality of experimental results will be improved obviously. This paper used an imaging system at BL13W beamline of Shanghai Synchrotron Radiation Facility (SSRF) to study the matching relation between the scintillator thickness and the NA of the microscope objective with a real sample. By use of the matching relation between the scintillator thickness and the NA of the microscope objective, the optimal imaging results have been obtained.

  19. High-position-resolution scintillation neutron-imaging detector by crossed-fiber readout with novel centroid-finding method

    CERN Document Server

    Katagiri, M; Sakasai, K; Matsubayashi, M; Birumachi, A; Takahashi, H; Nakazawa, M

    2002-01-01

    Aiming at high-position-resolution and high-counting-rate neutron imaging, a novel centroid-finding method is proposed for a scintillation neutron-imaging detector with crossed-fiber readout. Crossed wavelength-shifting fibers are arranged on and under the scintillator. Luminescences generated in the scintillator are emitted and detected by a few fibers surrounding the incident point of a neutron. In the novel method, X and Y positions of the incident neutron are decided by coincidence of a central signal and neighboring signals, respectively. By fundamental experiments using a ZnS:Ag/ sup 6 LiF scintillator of 0.5-mm thickness and crossed wavelength-shifting fibers with a size of 0.5 x 0.5 mm sup 2 , it was confirmed that the position resolution is about 0.5 mm and the limitation of the neutron-counting rate is 320 kcps. (orig.)

  20. Designation of Ray Detector Shielding Box for Radiation Imaging

    Institute of Scientific and Technical Information of China (English)

    CHUCheng-jie; XINGJian-sheng; JIAOChuan-rong

    2003-01-01

    The technology of radiation imaging plays an important role in the area of no-bug diagnosis. The principle is that the absorbed dose amount is different when rays go through objects with different material or thickness. According to the through ray intensity, we can get the characteristic picture of diagnostic objects. For this subject, the ray is from a 60Co point irradiation source.

  1. Designation of Ray Detector Shielding Box for Radiation Imaging

    Institute of Scientific and Technical Information of China (English)

    CHUCheng-jie; XINGJian-sheng; JIAOChuan-rong

    2003-01-01

    The technology of radiation imaging plays an important role in the area of no-bug diagnosis. The principle is that the absorbed dose is different when the rays go through objects with different material or thickness. According to the through ray intensity, we can get the characteristic picture of diagnostic objects. For this subject, the ray is from a 60Co point irradiation source.

  2. Development of a two-dimensional imaging GEM detector using the resistive anode readout method with $6\\times6$ cells

    CERN Document Server

    Ju, Xu-Dong; Zhou, Chuan-Xing; Dong, Jing; Zhao, Yu-Bin; Zhang, Hong-Yu; Qi, Hui-Rong; Ou-Yang, Qun

    2016-01-01

    We report the application of the resistive anode readout method on a two dimensional imaging GEM detector. The resistive anode consists $6\\times6$ cells with the cell size $6~\\mathrm{mm}\\times6~\\mathrm{mm}$. New electronics and DAQ system are used to process the signals from 49 readout channels. The detector has been tested by using the X-ray tube (8~keV). The spatial resolution of the detector is about $103.46~\\mathrm{{\\mu}m}$ with the signal part $66.41~\\mathrm{{\\mu}m}$. The nonlinearity of the detector is less than $0.5\\%$. A good two dimensional imaging capability is achieved as well. The performances of the detector show the prospect of the resistive anode readout method for the large readout area imaging detectors.

  3. A disc-DIRC-Detector for WASA at COSY as a test detector for PANDA rate at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Doroshkevich, Evgueni [Physikalisches Institut, Universitaet Tuebingen (Germany)

    2010-07-01

    For a precise measurement of the velocity of highly relativistic particles the detection of Cherenkov light is very attractive. Detectors based on the Detection of Internally Reflected Cherenkov Light (DIRC) - first built and used in the BaBar experiment - are also planned to be used in the PANDA detector at FAIR, both in form of a barrel-DIRC and in form of a disc-DIRC. In both cases the Cherenkov rings are reconstructed from the internally reflected Cherenkov light deflected into position sensitive detectors. For the WASA Forward Detector setup a Disc-DIRC is constructed, which serves both as a test module for PANDA and an important upgrade of the WASA detector. For an optimal performance at WASA the Disc-DIRC is tilted by 20 out of the vertical plane. The internally reflected Cherenkov light will be guided to multi-anode photomultipliers by focussing light guides. Both Disc-DIRC and focussing light guides will be made of plexiglass. Design, performance and time line of construction and implementation are discussed.

  4. Prospects of functional Magnetic Resonance Imaging as lie detector

    Directory of Open Access Journals (Sweden)

    Elena eRusconi

    2013-09-01

    Full Text Available Following the demise of the polygraph, supporters of assisted scientific lie detection tools have enthusiastically appropriated neuroimaging technologies as the savior of scientifically verifiable lie detection in the courtroom (Gerard, 2008: 5; however, such enthusiasm may prove premature. For in nearly every article published by independent researchers in peer reviewed journals, the respective authors acknowledge that fMRI research, processes, and technology are insufficiently developed and understood for gatekeepers to even consider introducing these neuroimaging measures into criminal courts as they stand today for the purpose of determining the veracity of statements made. Regardless of how favorable their analyses of fMRI or its future potential, they all acknowledge the presence of issues yet to be resolved. Even assuming a future where these issues are resolved and an appropriate fMRI lie-detection process is developed, its integration into criminal trials is not assured for the very success of such a future system may necessitate its exclusion from courtrooms on the basis of existing legal and ethical prohibitions. In this piece, aimed for a multidisciplinary readership, we seek to highlight and bring together the multitude of hurdles which would need to be successfully overcome before fMRI can (if ever be a viable applied lie detection system. We argue that the current status of fMRI studies on lie detection meets neither basic legal nor scientific standards. We identify four general classes of hurdles (scientific, legal and ethical, operational, and social and provide an overview on the stages and operations involved in fMRI studies, as well as the difficulties of translating these laboratory protocols into a practical criminal justice environment. It is our overall conclusion that fMRI is unlikely to constitute a viable lie detector for criminal courts.

  5. Coded Mask Imaging of High Energy X-rays with CZT Detectors

    Science.gov (United States)

    Matteson, J. L.; Dowkontt, P. F.; Duttweiler, F.; Heindl, W. A.; Hink, P. L.; Huszar, G. L.; Kalemci, E.; Leblanc, P. C.; Rothschild, R. E.; Skelton, R. T.; Slavis, K. R.; Stephan, E. A.

    1998-12-01

    Coded mask imagers are appropriate for important objectives of high energy X-ray astronomy, e.g., gamma- ray burst localization, all-sky monitors and surveys, and deep surveys of limited regions. We report results from a coded mask imager developed to establish the proof-of-concept for this technique with CZT detectors. The detector is 2 mm thick with orthogonal crossed strip readout and an advanced electrode design to improve the energy resolution. Each detector face has 22 strip electrodes, and the strip pitch and pixel size are 500 microns. ASIC readout is used and the energy resolution varies from 3 to 6 keV FWHM over the 14 to 184 keV keV range. A coded mask with 2 x 2 cycles of a 23 x 23 MURA pattern (860 micron unit cell) was built from 600 micron thick tantalum to provide good X-ray modulation up to 200 keV. The detector, mask, and a tiny Gd-153 source of 41 keV X-rays were positioned with a spacing that caused the mask cells in the shadowgram to have a projected size of 1300 microns at the detector. Multiple detector positions were used to measure the shadowgram of a full mask cycle and this was recorded with 100 percent modulation transfer by the detector, due to its factor of 2.6 oversampling of the mask unit cell, and very high strip-to-strip selectivity and spatial accuracy. Deconvolution of the shadowgram produced a correlation image in which the source was detected as a 76-sigma peak with the correct FWHM and base diameter. Off-source image pixels had gaussian fluctuations that agree closely with the measurement statistics. Off-source image defects such as might be produced by systematic effects were too small to be seen and limited to <0.5 percent of the source peak. These results were obtained with the "raw" shadowgram and image; no "flat fielding" corrections were used.

  6. AAPM/RSNA physics tutorial for residents: physics of flat-panel fluoroscopy systems: Survey of modern fluoroscopy imaging: flat-panel detectors versus image intensifiers and more.

    Science.gov (United States)

    Nickoloff, Edward Lee

    2011-01-01

    This article reviews the design and operation of both flat-panel detector (FPD) and image intensifier fluoroscopy systems. The different components of each imaging chain and their functions are explained and compared. FPD systems have multiple advantages such as a smaller size, extended dynamic range, no spatial distortion, and greater stability. However, FPD systems typically have the same spatial resolution for all fields of view (FOVs) and are prone to ghosting. Image intensifier systems have better spatial resolution with the use of smaller FOVs (magnification modes) and tend to be less expensive. However, the spatial resolution of image intensifier systems is limited by the television system to which they are coupled. Moreover, image intensifier systems are degraded by glare, vignetting, spatial distortions, and defocusing effects. FPD systems do not have these problems. Some recent innovations to fluoroscopy systems include automated filtration, pulsed fluoroscopy, automatic positioning, dose-area product meters, and improved automatic dose rate control programs. Operator-selectable features may affect both the patient radiation dose and image quality; these selectable features include dose level setting, the FOV employed, fluoroscopic pulse rates, geometric factors, display software settings, and methods to reduce the imaging time.

  7. Limitations of anti-scatter grids when used with high resolution image detectors

    Science.gov (United States)

    Singh, V.; Jain, A.; Bednarek, D. R.; Rudin, S.

    2014-03-01

    Anti-scatter grids are used in fluoroscopic systems to improve image quality by absorbing scattered radiation. A stationary Smit Rontgen X-ray grid (line density: 70 lines/cm, grid ratio: 13:1) was used with a flat panel detector (FPD) of pixel size 194 micron and a high-resolution CMOS detector, the Dexela 1207 with pixel size of 75 microns. To investigate the effectiveness of the grid, a simulated artery block was placed in a modified uniform frontal head phantom and imaged with both the FPD and the Dexela for an approximately 15 x 15 cm field of view (FOV). The contrast improved for both detectors with the grid. The contrast-to-noise ratio (CNR) does not increase as much in the case of the Dexela as it improves in the case of the FPD. Since the total noise in a single frame increases substantially for the Dexela compared to the FPD when the grid is used, the CNR is degraded. The increase in the quantum noise per frame would be similar for both detectors when the grid is used due to the attenuation of radiation, but the fixed pattern noise caused by the grid was substantially higher for the Dexela compared to the FPD and hence caused a severe reduction of CNR. Without further corrective methods this grid should not be used with high-resolution fluoroscopic detectors because the CNR does not improve significantly and the visibility of low contrast details may be reduced. Either an anti-scatter grid of different design or an additional image processing step when using a similar grid would be required to deal with the problem of scatter for high resolution detectors and the structured noise of the grid pattern.

  8. Analysis and operation of DePFET X-ray imaging detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lauf, Thomas

    2011-04-28

    The latest active pixel sensor for X-ray imaging spectroscopy developed at the Max-Planck-Halbleiterlabor (HLL) is the Depleted P-channel Field Effect Transistor (DePFET). This detector type unites detector and first stage amplification and has excellent energy resolution, low noise readout at high speed and low power consumption. This is combined with the possibility of random accessibility of pixels and on-demand readout. In addition it possesses all advantages of a sidewards depleted device, i.e. 100% fill factor and very good quantum efficiency. In the course of the development of DePFET detectors the need of a data analysis software for DePFET devices became apparent. A new tool was developed within the scope of this thesis, which should enable scientists to analyze DePFET data, but also be flexible enough so it can be adapted to new device variants and analysis challenges. A modular concept was thus implemented: a base program running an analysis by individual steps encapsulating algorithms, which can be interchanged. The result is a flexible, adaptable, and expandable analysis software. The software was used to investigate and qualify different structural variants of DePFET detectors. Algorithms to examine detector effects and methods to correct them were developed and integrated into the software. This way, a standard analysis suite for DePFET data was built up which is used at the HLL. Beside the planned use as detector for the wide field imager in the space X-ray observatory IXO, DePFET matrices will be used as focal plane array on the Mercury Imaging X-ray Spectrometer on board the Mercury probe BepiColombo which is scheduled for launch in 2014. The developed analysis software was used in the detector development for this mission to qualify test structures, analyze detector effects and study experimental results. In the course of this development, detector prototypes were studied in respect of linearity, charge collection and detection efficiency in an

  9. Effects, determination, and correction of count rate nonlinearity in multi-channel analog electron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Reber, T. J.; Plumb, N. C.; Waugh, J. A.; Dessau, D. S. [Department of Physics, University of Colorado, Boulder, Colorado 80309-0390 (United States)

    2014-04-15

    Detector counting rate nonlinearity, though a known problem, is commonly ignored in the analysis of angle resolved photoemission spectroscopy where modern multichannel electron detection schemes using analog intensity scales are used. We focus on a nearly ubiquitous “inverse saturation” nonlinearity that makes the spectra falsely sharp and beautiful. These artificially enhanced spectra limit accurate quantitative analysis of the data, leading to mistaken spectral weights, Fermi energies, and peak widths. We present a method to rapidly detect and correct for this nonlinearity. This algorithm could be applicable for a wide range of nonlinear systems, beyond photoemission spectroscopy.

  10. Combination of a silicon photodiode and a scintillator as a dose rate detector

    Energy Technology Data Exchange (ETDEWEB)

    Gilar, O. (Tesla, Premysleni (Czechoslovakia). Vyzkumny Ustav Pristroju Jaderne Techniky); Petr, I. (Ceske Vysoke Uceni Technicke, Prague (Czechoslovakia). Fakulta Jaderna a Fysikalne Inzenyrska)

    1985-03-16

    The combination of a silicon photodiode adjacent to a CsI(Tl) scintillator as a detector of ..gamma..-rays is described. Theoretical conclusions are verified by an experiment and prove that the photodiode absorption spectrum as well as the quantum efficiency can be varied by an appropriate photodiode technology. The contribution of scintillation photons emitted by the CsI(Tl) scintillator in the photon field can enhance the total photocurrent more than an order of magnitude compared to the current response of the photodiode alone, placed in a photon field of equal exposure rate.

  11. Multi-anode microchannel arrays - New detectors for imaging and spectroscopy in space

    Science.gov (United States)

    Timothy, J. G.; Bybee, R. L.

    1983-01-01

    Consideration is given to the construction and operation of multi-anode microchannel array detector systems having formats as large as 256 x 1024 pixels. Such arrays are being developed for imaging and spectroscopy at soft X-ray, ultraviolet and visible wavelengths from balloons, sounding rockets and space probes. Both discrete-anode and coincidence-anode arrays are described. Two types of photocathode structures are evaluated: an opaque photocathode deposited directly on the curved-channel MCP and an activated cathode deposited on a proximity-focused mesh. Future work will include sensitivity optimization in the different wavelength regions and the development of detector tubes with semitransparent proximity-focused photocathodes.

  12. Tissue sensitive imaging and tomography without contrast agents for small animals with Timepix based detectors

    Science.gov (United States)

    Trojanova, E.; Schyns, L. E. J. R.; Ludwig, D.; Jakubek, J.; Le Pape, A.; Sefc, L.; Lotte, S.; Sykora, V.; Turecek, D.; Uher, J.; Verhaegen, F.

    2017-01-01

    The tissue type resolving X-ray radiography and tomography can be performed even without contrast agents. The differences between soft tissue types such as kidney, muscles, fat, liver, brain and spleen were measured based on their spectral response. The Timepix based X-ray imaging detector WidePIX2×5 with 300 μm thick silicon sensors was used for most of the measurements presented in this work. These promising results are used for further optimizations of the detector technology and radiographic methods.

  13. Electronic readout system for the Belle II imaging Time-Of-Propagation detector

    Science.gov (United States)

    Kotchetkov, Dmitri

    2017-07-01

    The imaging Time-Of-Propagation (iTOP) detector, constructed for the Belle II experiment at the SuperKEKB e+e- collider, is an 8192-channel high precision Cherenkov particle identification detector with timing resolution below 50 ps. To acquire data from the iTOP, a novel front-end electronic readout system was designed, built, and integrated. Switched-capacitor array application-specific integrated circuits are used to sample analog signals. Triggering, digitization, readout, and data transfer are controlled by Xilinx Zynq-7000 system on a chip devices.

  14. Trends in the development of large area photon detectors for Cherenkov light imaging applications

    CERN Document Server

    Nappi, E

    2003-01-01

    Since the successful operations of hi-tech devices at OMEGA, DELPHI and SLD, the technique of Cherenkov light imaging has gone through an impressive and fruitful evolution driven by the conception of novel large area photon detectors. The well-assessed potentialities of thin CsI films, employed as reflective photoconverters in gas counters operated at atmospheric pressure, will be compared with the promising features of hybrid and multianode vacuum photomultipliers. Recently proposed single-photon gaseous detectors based on GEMs will also be reviewed.

  15. 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...

  16. 2010 IEEE Nuclear Science Symposium, Medical Imaging Conference, and Room Temperature Semiconductor Detectors Workshop

    Science.gov (United States)

    The Nuclear Science Symposium (NSS) offers an outstanding opportunity for scientists and engineers interested or actively working in the fields of nuclear science, radiation instrumentation, software and their applications, to meet and discuss with colleagues from around the world. The program emphasizes the latest developments in technology and instrumentation and their implementation in experiments for space sciences, accelerators, other radiation environments, and homeland security. The Medical Imaging Conference (MIC) is the foremost international scientific meeting on the physics, engineering and mathematical aspects of nuclear medicine based imaging. As the field develops, multi-modality approaches are becoming more and more important. The content of the MIC reflects this, with a growing emphasis on the methodologies of X-ray, optical and MR imaging as they relate to nuclear imaging techniques. In addition, specialized topics will be addressed in the Short Courses and Workshops programs. The Workshop on Room-Temperature Semiconductor Detectors (RTSD) represents the largest forum of scientists and engineers developing new semiconductor radiation detectors and imaging arrays. Room-temperature solid-state radiation detectors for X-ray, gamma-ray, and neutron radiation are finding increasing applications in such diverse fields as medicine, homeland security, astrophysics and environmental remediation. The objective of this workshop is to provide a forum for discussion of the state of the art of material development for semiconductor, scintillator, and organic materials for detection, materials characterization, device fabrication and technology, electronics and applications.

  17. Improving x-ray image resolution using subpixel shifts of the detector

    Science.gov (United States)

    Bruandet, Jean-Pierre; Dinten, Jean-Marc

    1999-05-01

    The resolution of digitized images is linked to the detector array pixel size. Aliasing effects result from a non- adequation between the detector sampling and the signal bandwidths. The aim of this study is to develop a super- resolution algorithm for X-ray images. Our technique uses controlled horizontal and vertical subpixel shifts. Generalized sampling theorem of Papoulis, based on a multichannel approach, is the theoretical justification for the recovery of a high resolution image thanks to a set of low resolution ones. A higher resolution image is recovered by a minimization of a quadratic criterion. An iterative relaxation method is used to compute the minimum. To regularize, a priori data about the signal are introduced in order to fight against noise effects. Because of the opposite effects of regularization and super-resolution an adapted regularization that preserves discontinuities has to be used. Results obtained show that our algorithm recovers high frequency components on X-ray images without noise amplification. An analysis of real acquisitions in terms of modulation transfer function (MTF) shows that we obtain, thanks to this method, a 'virtual' detector better than a low resolution one, and equivalent to a real high resolution one.

  18. Oversampling advances in millimeter-wave scan imaging using inexpensive neon indicator lamp detectors

    Science.gov (United States)

    Levanon, Assaf; Kopeika, Natan S.; Yitzhaky, Yitzhak; Abramovich, Amir; Rozban, Daniel; Joseph, Hezi; Aharon, Avihai; Belenky, Alex; Gefen, Michael; Yadid-Pecht, Orly

    2013-06-01

    In recent years, much effort has been invested to develop room temperature inexpensive, but sensitive, millimeter wave (MMW) and terahertz (THz) detectors that can be used as pixels in focal plane arrays, which is important for real-time imaging. A new 18×2 neon indicator lamp MMW/THz scanner was developed. The components of the camera include horizontally shifted two-column glow discharge detectors in a scanning array. The detectors, costing about 50 cents each, are wired to a preprocessing card, a VLSI board, and a motor for scanner movement. A description of the VLSI Verilog programmable hardware of the new scanner, the physical architecture, the software user interface, and imaging results at 97 GHz are presented. At this stage, the emphasis is focused on the lamp exposure time and spatial resolution when the scanning is performed horizontally. In the future it is planned to expose all pixels simultaneously for real-time imaging. New software capabilities allow the application of digital image enhancement algorithms. Fast scanning permits obtaining images in 1 to 5 s. Oversampling yields a sharper edge response and a higher signal-to-noise ratio.

  19. Comparison of X-ray detectors for a diffraction enhanced imaging system

    CERN Document Server

    Kiss, M Z; Zhong Zhon

    2002-01-01

    Three digital detector systems--a Fuji BAS2500 Image Plate Reader, a prototype charge-coupled device (CCD) from Mar USA and the MicroPhotonics XQUIS 1000 were compared with respect to format, dynamic range, dark noise, and spatial resolution. Experiments were conducted using highly collimated monochromatic X-rays at 20 keV, produced at the National Synchrotron Light Source. This study characterized digital detectors being considered for integration into a synchrotron-based diffraction enhanced imaging (DEI) apparatus used for medical imaging research, particularly mammography. These detectors are also being considered for integration into a proposed clinical prototype for DEI-based mammography. While all three systems had comparable image quality, the CCDs had faster readout time than the image plate system. However, the Fuji system had the largest dynamic range (approx 10 sup 5 compared to 10 sup 4 for CCDs) and the largest active area. The MicroPhotonics XQUIS 1000 had the best spatial resolution as charact...

  20. Impact of detector geometry for compressive fan beam snapshot coherent scatter imaging

    Science.gov (United States)

    Hassan, Mehadi; Holmgren, Andrew; Greenberg, Joel A.; Odinaka, Ikenna; Brady, David

    2016-05-01

    Previous realizations of coded-aperture X-ray diffraction tomography (XRDT) techniques based on pencil beams image one line through an object via a single measurement but require raster scanning the object in multiple dimensions. Fan beam approaches are able to image the spatial extent of the object while retaining the ability to do material identification. Building on these approaches we present our system concept and geometry of combining a fan beam with energy sensitive/photon counting detectors and a coded aperture to capture both spatial and spectral information about an object at each voxel. Using our system we image slices via snapshot measurements for four different detector configurations and compare their results.

  1. Differential Imaging with a Multicolor Detector Assembly: A New ExoPlanet Finder Concept

    CERN Document Server

    Marois, C; Doyon, R; Lafrenière, D; Nadeau, D

    2004-01-01

    Simultaneous spectral differential imaging is a high contrast technique by which subtraction of simultaneous images reduces noise from atmospheric speckles and optical aberrations. Small non-common wave front errors between channels can seriously degrade its performance. We present a new concept, a multicolor detector assembly (MCDA), which can eliminate this problem. The device consists of an infrared detector and a microlens array onto the flat side of which a checkerboard pattern of narrow-band micro-filters is deposited, each micro-filter coinciding with a microlens. Practical considerations for successful implementation of the technique are mentioned. Numerical simulations predict a noise attenuation of 10^-3 at 0.5" for a 10^5 seconds integration on a mH=5 star of Strehl ratio 0.9 taken with an 8-m telescope. This reaches a contrast of 10^-7 at an angular distance of 0.5" from the center of the star image.

  2. Patient-dependent count-rate adaptive normalization for PET detector efficiency with delayed-window coincidence events.

    Science.gov (United States)

    Niu, Xiaofeng; Ye, Hongwei; Xia, Ting; Asma, Evren; Winkler, Mark; Gagnon, Daniel; Wang, Wenli

    2015-07-07

    Quantitative PET imaging is widely used in clinical diagnosis in oncology and neuroimaging. Accurate normalization correction for the efficiency of each line-of- response is essential for accurate quantitative PET image reconstruction. In this paper, we propose a normalization calibration method by using the delayed-window coincidence events from the scanning phantom or patient. The proposed method could dramatically reduce the 'ring' artifacts caused by mismatched system count-rates between the calibration and phantom/patient datasets. Moreover, a modified algorithm for mean detector efficiency estimation is proposed, which could generate crystal efficiency maps with more uniform variance. Both phantom and real patient datasets are used for evaluation. The results show that the proposed method could lead to better uniformity in reconstructed images by removing ring artifacts, and more uniform axial variance profiles, especially around the axial edge slices of the scanner. The proposed method also has the potential benefit to simplify the normalization calibration procedure, since the calibration can be performed using the on-the-fly acquired delayed-window dataset.

  3. Single-photon detectors combining near unity efficiency, ultra-high detection-rates, and ultra-high time resolution

    CERN Document Server

    Zadeh, Iman Esmaeil; Gourgues, Ronan B M; Steinmetz, Violette; Dobrovolskiy, Sergiy M; Zwiller, Val; Dorenbos, Sander N

    2016-01-01

    Single-photon detection with high efficiency, high time resolution, low dark counts and high photon detection-rates is required for a wide range of optical measurements. Although efficient detectors have been reported, combining all performances in a single device remains a challenge. Here, we show a broadband NbTiN superconducting nanowire detector with an efficiency over 92%, over 150MHz photon detection-rate and dark counts below 130Hz operated in a conventional Gifford-McMahon cryostat. Furthermore, with an optimized detector and readout electronics, we reach a record low jitter of 14.80ps while maintaining high efficiency.

  4. Integration of flat panel X-ray detector for high resolution diagnostic medical imaging

    Science.gov (United States)

    Kim, Min-Woo; Yun, Min-Seok; Kim, Yoon-Suk; Oh, Kyung-Min; Shin, Jung-Wook; Nam, Kyung-Tae; Nam, Sang-Hee

    2011-05-01

    In these days, flat panel X-ray image detectors have shown their potential for replacing traditional screen-film systems. To detect the X-ray photon energy, there are two main methods known as a direct method and an indirect method. The X-rays are converted immediately into electrical signal with the direct method. The indirect method has two conversion steps: the scintillator absorbs the X-rays and converts them to visible light. And then the visible light is converted to electrical signal (e.g. by photodiodes). In this work, the flat panel digital X-ray image detector based on direct method with a high atomic number material was designed and evaluated. The high atomic number material for X-ray conversion is deposited by a rubbing method with about 300 μm. The rubbing method is similar to the screen printing method. It consists of two elements: the screen and the squeegee. The method uses a proper stiff bar stretched tightly over a frame made of wood or metal. Proper tension is essential for proper laminated structure. The detector prototype has 139 μm pixel pitch, total 1280×1536 pixels and 86% fill factor. Twelve readout ICs are installed on digital X-ray detector and simultaneously operated to reach short readout time. The electronics integrated: the preamplifier to amplify generated signal, the Analog to Digital converter and the source of bias voltage (1 V/μm). The system board and interface use an NI-camera program. Finally, we achieved images from this flat panel X-ray image detector.

  5. 3D imaging of particle tracks in Solid State Nuclear Track Detectors

    Science.gov (United States)

    Wertheim, D.; Gillmore, G.; Brown, L.; Petford, N.

    2009-04-01

    Inhalation of radon gas (222Rn) and associated ionizing decay products is known to cause lung cancer in human. In the U.K., it has been suggested that 3 to 5 % of total lung cancer deaths can be linked to elevated radon concentrations in the home and/or workplace. Radon monitoring in buildings is therefore routinely undertaken in areas of known risk. Indeed, some organisations such as the Radon Council in the UK and the Environmental Protection Agency in the USA, advocate a ‘to test is best' policy. Radon gas occurs naturally, emanating from the decay of 238U in rock and soils. Its concentration can be measured using CR?39 plastic detectors which conventionally are assessed by 2D image analysis of the surface; however there can be some variation in outcomes / readings even in closely spaced detectors. A number of radon measurement methods are currently in use (for examples, activated carbon and electrets) but the most widely used are CR?39 solid state nuclear track?etch detectors (SSNTDs). In this technique, heavily ionizing alpha particles leave tracks in the form of radiation damage (via interaction between alpha particles and the atoms making up the CR?39 polymer). 3D imaging of the tracks has the potential to provide information relating to angle and energy of alpha particles but this could be time consuming. Here we describe a new method for rapid high resolution 3D imaging of SSNTDs. A ‘LEXT' OLS3100 confocal laser scanning microscope was used in confocal mode to successfully obtain 3D image data on four CR?39 plastic detectors. 3D visualisation and image analysis enabled characterisation of track features. This method may provide a means of rapid and detailed 3D analysis of SSNTDs. Keywords: Radon; SSNTDs; confocal laser scanning microscope; 3D imaging; LEXT

  6. Extensive simulation studies on the reconstructed image resolution of a position sensitive detector based on pixelated CdTe crystals

    CERN Document Server

    Zachariadou, K; Kaissas, I; Seferlis, S; Lambropoulos, C; Loukas, D; Potiriadis, C

    2011-01-01

    We present results on the reconstructed image resolution of a position sensitive radiation instrument (COCAE) based on extensive simulation studies. The reconstructed image resolution has been investigated in a wide range of incident photon energies emitted by point-like sources located at different source-to-detector distances on and off the detector's symmetry axis. The ability of the detector to distinguish multiple radioactive sources observed simultaneously is investigating by simulating point-like sources of different energies located on and off the detector's symmetry axis and at different positions

  7. Design and image-quality performance of high resolution CMOS-based X-ray imaging detectors for digital mammography

    Science.gov (United States)

    Cha, B. K.; Kim, J. Y.; Kim, Y. J.; Yun, S.; Cho, G.; Kim, H. K.; Seo, C.-W.; Jeon, S.; Huh, Y.

    2012-04-01

    In digital X-ray imaging systems, X-ray imaging detectors based on scintillating screens with electronic devices such as charge-coupled devices (CCDs), thin-film transistors (TFT), complementary metal oxide semiconductor (CMOS) flat panel imagers have been introduced for general radiography, dental, mammography and non-destructive testing (NDT) applications. Recently, a large-area CMOS active-pixel sensor (APS) in combination with scintillation films has been widely used in a variety of digital X-ray imaging applications. We employed a scintillator-based CMOS APS image sensor for high-resolution mammography. In this work, both powder-type Gd2O2S:Tb and a columnar structured CsI:Tl scintillation screens with various thicknesses were fabricated and used as materials to convert X-ray into visible light. These scintillating screens were directly coupled to a CMOS flat panel imager with a 25 × 50 mm2 active area and a 48 μm pixel pitch for high spatial resolution acquisition. We used a W/Al mammographic X-ray source with a 30 kVp energy condition. The imaging characterization of the X-ray detector was measured and analyzed in terms of linearity in incident X-ray dose, modulation transfer function (MTF), noise-power spectrum (NPS) and detective quantum efficiency (DQE).

  8. Design and First Results of the CoDeX Liquid-Xenon Compton-Imaging Detector

    Science.gov (United States)

    Tennyson, Brian; Cahn, Sidney; Bernard, Ethan; Boulton, Elizabeth; Destefano, Nicholas; Edwards, Blair; Hackenburg, Ariana; Horn, Markus; Larsen, Nicole; Nikkel, James; Wahl, Christopher; Gai, Moshe; McKinsey, Daniel

    2016-03-01

    CoDeX (Compton-imaging Detector in Xenon) is an R&D Compton gamma-ray imaging detector that uses 30 kg of xenon in a two-phase time projection chamber. Time projection relative to the initial scintillation signal provides the vertical interaction positions, and either PMT-sensed gas electroluminescence or a charge-sensitive amplifier quantifies the drifted ionization signal. Detector features to enable Compton imaging are a pair of instrumented wire grids added to sense the horizontal position of clouds of drifted electrons that traverse the detector. Each wire is individually amplified in the cold xenon environment. Design choices addressing the thermodynamic and xenon purity constraints of this system will be discussed. We will also discuss the mechanical designs, engineering challenges, and performance of this Compton-imaging detector.

  9. A generic FPGA-based detector readout and real-time image processing board

    CERN Document Server

    Sarpotdar, Mayuresh; Safonova, Margarita; Murthy, Jayant

    2016-01-01

    For space-based astronomical observations, it is important to have a mechanism to capture the digital output from the standard detector for further on-board analysis and storage. We have developed a generic (application- wise) field-programmable gate array (FPGA) board to interface with an image sensor, a method to generate the clocks required to read the image data from the sensor, and a real-time image processor system (on-chip) which can be used for various image processing tasks. The FPGA board is applied as the image processor board in the Lunar Ultraviolet Cosmic Imager (LUCI) and a star sensor (StarSense) (instruments developed by our group). In this paper, we discuss the various design considerations for this board and its applications in the future balloon and possible space flights.

  10. Maximum likelihood positioning for gamma-ray imaging detectors with depth of interaction measurement

    Energy Technology Data Exchange (ETDEWEB)

    Lerche, Ch.W. [Grupo de Sistemas Digitales, ITACA, Universidad Politecnica de Valencia, 46022 Valencia (Spain)], E-mail: lerche@ific.uv.es; Ros, A. [Grupo de Fisica Medica Nuclear, IFIC, Universidad de Valencia-Consejo Superior de Investigaciones Cientificas, 46980 Paterna (Spain); Monzo, J.M.; Aliaga, R.J.; Ferrando, N.; Martinez, J.D.; Herrero, V.; Esteve, R.; Gadea, R.; Colom, R.J.; Toledo, J.; Mateo, F.; Sebastia, A. [Grupo de Sistemas Digitales, ITACA, Universidad Politecnica de Valencia, 46022 Valencia (Spain); Sanchez, F.; Benlloch, J.M. [Grupo de Fisica Medica Nuclear, IFIC, Universidad de Valencia-Consejo Superior de Investigaciones Cientificas, 46980 Paterna (Spain)

    2009-06-01

    The center of gravity algorithm leads to strong artifacts for gamma-ray imaging detectors that are based on monolithic scintillation crystals and position sensitive photo-detectors. This is a consequence of using the centroids as position estimates. The fact that charge division circuits can also be used to compute the standard deviation of the scintillation light distribution opens a way out of this drawback. We studied the feasibility of maximum likelihood estimation for computing the true gamma-ray photo-conversion position from the centroids and the standard deviation of the light distribution. The method was evaluated on a test detector that consists of the position sensitive photomultiplier tube H8500 and a monolithic LSO crystal (42mmx42mmx10mm). Spatial resolution was measured for the centroids and the maximum likelihood estimates. The results suggest that the maximum likelihood positioning is feasible and partially removes the strong artifacts of the center of gravity algorithm.

  11. Neutron imaging detector based on the muPIC micro-pixel chamber

    CERN Document Server

    Parker, J D; Fujioka, H; Harada, M; Iwaki, S; Kabuki, S; Kishimoto, Y; Kubo, H; Kurosawa, S; Miuchi, K; Nagae, T; Nishimura, H; Oku, T; Sawano, T; Shinohara, T; Suzuki, J; Takada, A; Tanimori, T; Ueno, K

    2012-01-01

    We have developed a prototype time-resolved neutron imaging detector employing the micro-pixel chamber (muPIC), a micro-pattern gaseous detector, coupled with a field programmable gate array-based data acquisition system for applications in neutron radiography at high-intensity neutron sources. The prototype system, with an active area of 10cm x 10cm and operated at a gas pressure of 2 atm, measures both the energy deposition (via time-over-threshold) and 3-dimensional track of each neutron-induced event, allowing the reconstruction of the neutron interaction point with improved accuracy. Using a simple position reconstruction algorithm, a spatial resolution of 349 +/- 36 microns was achieved, with further improvement expected. The detailed tracking allows strong rejection of background gamma-rays, resulting in an effective gamma sensitivity of 10^-12 or less, coupled with stable, robust neutron identification. The detector also features a time resolution of 0.6 microseconds.

  12. Improvement of an X-ray imaging detector based on a scintillating guides screen

    CERN Document Server

    Badel, X; Linnros, J; Kleimann, P; Froejdh, C; Petersson, C S

    2002-01-01

    An X-ray imaging detector has been developed for dental applications. The principle of this detector is based on application of a silicon charge coupled device covered by a scintillating wave-guide screen. Previous studies of such a detector showed promising results concerning the spatial resolution but low performance in terms of signal to noise ratio (SNR) and sensitivity. Recent results confirm the wave-guiding properties of the matrix and show improvement of the detector in terms of response uniformity, sensitivity and SNR. The present study is focussed on the fabrication of the scintillating screen where the principal idea is to fill a matrix of Si pores with a CsI scintillator. The photoluminescence technique was used to prove the wave-guiding property of the matrix and to inspect the filling uniformity of the pores. The final detector was characterized by X-ray evaluation in terms of spatial resolution, light output and SNR. A sensor with a spatial resolution of 9 LP/mm and a SNR over 50 has been achie...

  13. A multi-stage image charge detector made from printed circuit boards.

    Science.gov (United States)

    Barney, Brandon L; Daly, R Terik; Austin, Daniel E

    2013-11-01

    We present the first reported instance of an image-charge detector for charged particles in which detection elements are patterned onto printed circuit boards. In contrast to conventional techniques involving separately machined and positioned segments of metal tubing, this technique is much simpler to assemble, align, and connect to electrical wiring, with no loss in sensitivity. The performance of single-stage and 5-stage charge detectors is demonstrated using electrospray-charged, micrometer-size polystyrene spheres. Both velocity and charge of each particle are measured. Multiple detection stages--which require no extra effort to pattern or setup compared with a single stage--result in an ensemble averaging effect, improving the detection limit over what can be achieved with a single-stage detector. A comparison is made between the printed circuit board detector and a conventional tubular charge detector and found to be statistically equivalent. These results demonstrate and illustrate that devices for detection, analysis, and/or manipulation of charged particles and ions can be made using printed circuit boards rather than using separately fabricated metal electrodes.

  14. Imaging results and TOF studies with axial PET detectors

    CERN Document Server

    Joram, Christian

    2013-01-01

    We have developed a fully operational PET demonstrator setup which allows true 3D reconstruction of the 511 keV photons and therefore leads to practically parallax free images. The AX-PET concept is based on thin 100 mm long scintillation crystals (LYSO), axially oriented and arranged in layers around the held of view. Layers of wavelength shifting plastic strips mounted in between the crystal layers give the axial coordinate. Both crystals and WLS strips are individually read out by G-APD (SiPM) photodetectors. The Fully scalable concept overcomes the dilemma of sensitivity versus spatial resolution which is inherent to classical PET designs. A demonstrator set-up based on two axial modules was exhaustively characterized using point-like sources, phantoms filled with radiotracer and finally rats and a mouse. The results entirely meet the performance expectations ( <2 mm FWHM in all three coordinates over the complete held of view) and also demonstrated the ability to include Compton interactions (inter-cr...

  15. A Ring Artifact Correction Method: Validation by Micro-CT Imaging with Flat-Panel Detectors and a 2D Photon-Counting Detector

    Directory of Open Access Journals (Sweden)

    Mohamed Elsayed Eldib

    2017-01-01

    Full Text Available We introduce an efficient ring artifact correction method for a cone-beam computed tomography (CT. In the first step, we correct the defective pixels whose values are close to zero or saturated in the projection domain. In the second step, we compute the mean value at each detector element along the view angle in the sinogram to obtain the one-dimensional (1D mean vector, and we then compute the 1D correction vector by taking inverse of the mean vector. We multiply the correction vector with the sinogram row by row over all view angles. In the third step, we apply a Gaussian filter on the difference image between the original CT image and the corrected CT image obtained in the previous step. The filtered difference image is added to the corrected CT image to compensate the possible contrast anomaly that may appear due to the contrast change in the sinogram after removing stripe artifacts. We applied the proposed method to the projection data acquired by two flat-panel detectors (FPDs and a silicon-based photon-counting X-ray detector (PCXD. Micro-CT imaging experiments of phantoms and a small animal have shown that the proposed method can greatly reduce ring artifacts regardless of detector types. Despite the great reduction of ring artifacts, the proposed method does not compromise the original spatial resolution and contrast.

  16. A Ring Artifact Correction Method: Validation by Micro-CT Imaging with Flat-Panel Detectors and a 2D Photon-Counting Detector

    Science.gov (United States)

    Eldib, Mohamed Elsayed; Hegazy, Mohamed; Mun, Yang Ji; Cho, Myung Hye; Cho, Min Hyoung; Lee, Soo Yeol

    2017-01-01

    We introduce an efficient ring artifact correction method for a cone-beam computed tomography (CT). In the first step, we correct the defective pixels whose values are close to zero or saturated in the projection domain. In the second step, we compute the mean value at each detector element along the view angle in the sinogram to obtain the one-dimensional (1D) mean vector, and we then compute the 1D correction vector by taking inverse of the mean vector. We multiply the correction vector with the sinogram row by row over all view angles. In the third step, we apply a Gaussian filter on the difference image between the original CT image and the corrected CT image obtained in the previous step. The filtered difference image is added to the corrected CT image to compensate the possible contrast anomaly that may appear due to the contrast change in the sinogram after removing stripe artifacts. We applied the proposed method to the projection data acquired by two flat-panel detectors (FPDs) and a silicon-based photon-counting X-ray detector (PCXD). Micro-CT imaging experiments of phantoms and a small animal have shown that the proposed method can greatly reduce ring artifacts regardless of detector types. Despite the great reduction of ring artifacts, the proposed method does not compromise the original spatial resolution and contrast. PMID:28146088

  17. Investigation of the LabPET™ detector and electronics for photon-counting CT imaging

    Science.gov (United States)

    Bérard, Philippe; Riendeau, Joel; Pepin, Catherine M.; Rouleau, Daniel; Cadorette, Jules; Fontaine, Réjean; Lecomte, Roger

    2007-02-01

    The development of new molecular probes targeting receptors with high specificity in selected cells and tissues highlights the importance of obtaining the anatomical context in Positron Emission Tomography (PET) imaging. This can be achieved using another imaging modality, such as X-ray Computed Tomography (CT) or Magnetic Resonance Imaging (MRI), but the anatomic and molecular images obtained sequentially with different scanners must subsequently be co-registered and are subjected to motion artifacts. Conventional CT imaging also contributes a significant dose, which may compromise the benefits of longitudinal molecular imaging studies in the same subject. To overcome these difficulties, we have investigated the use of the LabPET™ detector and electronics as a multi-modal detection system. Based on fast light emitting inorganic scintillators individually coupled to avalanche photodiodes and parallel, low-noise, fast digital processing electronics, the proposed detector front-end is suitable for coincidence detection of annihilation radiation (511 keV) in PET and for ultra-fast low-energy X-ray photon counting in CT. This combined detection system enables concurrent PET/CT imaging while potentially achieving superior image contrast sensitivity for a given dose in CT photon-counting mode. Anatomical images with millimeter spatial resolution and sufficient tissue contrast for anatomical localization in small animals have been obtained with doses in the mGy range. The CT performance for dual-modality imaging of small animals was analyzed in terms of spatial resolution, noise and image contrast sensitivity as a function of dose.

  18. Calibration of Cherenkov detectors for monoenergetic photon imaging in active interrogation applications

    Science.gov (United States)

    Rose, P. B.; Erickson, A. S.

    2015-11-01

    Active interrogation of cargo containers using monoenergetic photons offers a rapid and low-dose approach to search for shielded special nuclear materials. Cherenkov detectors can be used for imaging of the cargo provided that gamma ray energies used in interrogation are well resolved, as the case in 11B(d,n-γ)12C reaction resulting in 4.4 MeV and 15.1 MeV photons. While an array of Cherenkov threshold detectors reduces low energy background from scatter while providing the ability of high contrast transmission imaging, thus confirming the presence of high-Z materials, these detectors require a special approach to energy calibration due to the lack of resolution. In this paper, we discuss the utility of Cherenkov detectors for active interrogation with monoenergetic photons as well as the results of computational and experimental studies of their energy calibration. The results of the studies with sources emitting monoenergetic photons as well as complex gamma ray spectrum sources, for example 232Th, show that calibration is possible as long as the energies of photons of interest are distinct.

  19. GATE simulation of a LYSO-based SPECT imager: Validation and detector optimization

    Energy Technology Data Exchange (ETDEWEB)

    Li, Suying [Department of Biomedicine and Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing 100871 (China); Zhang, Qiushi [Institute for Drug and Instrument Control of Health Department GLD of PLA, No. 17 Fengtai West Road, Beijing 100071 (China); Xie, Zhaoheng; Liu, Qi [Department of Biomedicine and Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing 100871 (China); Xu, Baixuan [The General Hospital of Chinese People’s Liberation Army, No. 28 Fuxing Road, Beijing 100039 (China); Yang, Kun; Li, Changhui [Department of Biomedicine and Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing 100871 (China); Ren, Qiushi, E-mail: renqsh@coe.pku.edu.cn [Department of Biomedicine and Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing 100871 (China)

    2015-02-11

    This paper presents a small animal SPECT system that is based on cerium doped lutetium–yttrium oxyorthosilicate (LYSO) scintillation crystal, position sensitive photomultiplier tubes (PSPMTs) and parallel hole collimator. Spatial resolution test and animal experiment were performed to demonstrate the imaging performance of the detector. Preliminary results indicated a spatial resolution of 2.5 mm at FWHM that cannot meet our design requirement. Therefore, we simulated this gamma camera using GATE (GEANT 4 Application for Tomographic Emission) aiming to make detector spatial resolution less than 2 mm. First, the GATE simulation process was validated through comparison between simulated and experimental data. This also indicates the accuracy and effectiveness of GATE simulation for LYSO-based gamma camera. Then the different detector sampling methods (crystal size with 1.5, and 1 mm) and collimator design (collimator height with 30, 34.8, 38, and 43 mm) were studied to figure out an optimized parameter set. Detector sensitivity changes were also focused on with different parameters set that generated different spatial resolution results. Tradeoff curves of spatial resolution and sensitivity were plotted to determine the optimal collimator height with different sampling methods. Simulation results show that scintillation crystal size of 1 mm and collimator height of 38 mm, which can generate a spatial resolution of ∼1.8 mm and sensitivity of ∼0.065 cps/kBq, can be an ideal configuration for our SPECT imager design.

  20. Using compressive sensing to recover images from PET scanners with partial detector rings

    Energy Technology Data Exchange (ETDEWEB)

    Valiollahzadeh, SeyyedMajid, E-mail: sv4@rice.edu [Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005 and Department of Imaging Physics Unit 1352, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Clark, John W. [Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005 (United States); Mawlawi, Osama [Department of Imaging Physics Unit 1352, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States)

    2015-01-15

    Purpose: Most positron emission tomography/computed tomography (PET/CT) scanners consist of tightly packed discrete detector rings to improve scanner efficiency. The authors’ aim was to use compressive sensing (CS) techniques in PET imaging to investigate the possibility of decreasing the number of detector elements per ring (introducing gaps) while maintaining image quality. Methods: A CS model based on a combination of gradient magnitude and wavelet domains (wavelet-TV) was developed to recover missing observations in PET data acquisition. The model was designed to minimize the total variation (TV) and L1-norm of wavelet coefficients while constrained by the partially observed data. The CS model also incorporated a Poisson noise term that modeled the observed noise while suppressing its contribution by penalizing the Poisson log likelihood function. Three experiments were performed to evaluate the proposed CS recovery algorithm: a simulation study, a phantom study, and six patient studies. The simulation dataset comprised six disks of various sizes in a uniform background with an activity concentration of 5:1. The simulated image was multiplied by the system matrix to obtain the corresponding sinogram and then Poisson noise was added. The resultant sinogram was masked to create the effect of partial detector removal and then the proposed CS algorithm was applied to recover the missing PET data. In addition, different levels of noise were simulated to assess the performance of the proposed algorithm. For the phantom study, an IEC phantom with six internal spheres each filled with F-18 at an activity-to-background ratio of 10:1 was used. The phantom was imaged twice on a RX PET/CT scanner: once with all detectors operational (baseline) and once with four detector blocks (11%) turned off at each of 0 °, 90 °, 180 °, and 270° (partially sampled). The partially acquired sinograms were then recovered using the proposed algorithm. For the third test, PET images

  1. High rate particle tracking and ultra-fast timing with a thin hybrid silicon pixel detector

    Science.gov (United States)

    Fiorini, M.; Aglieri Rinella, G.; Carassiti, V.; Ceccucci, A.; Cortina Gil, E.; Cotta Ramusino, A.; Dellacasa, G.; Garbolino, S.; Jarron, P.; Kaplon, J.; Kluge, A.; Marchetto, F.; Mapelli, A.; Martin, E.; Mazza, G.; Morel, M.; Noy, M.; Nuessle, G.; Perktold, L.; Petagna, P.; Petrucci, F.; Poltorak, K.; Riedler, P.; Rivetti, A.; Statera, M.; Velghe, B.

    2013-08-01

    The Gigatracker (GTK) is a hybrid silicon pixel detector designed for the NA62 experiment at CERN. The beam spectrometer, made of three GTK stations, has to sustain high and non-uniform particle rate (∼ 1 GHz in total) and measure momentum and angles of each beam track with a combined time resolution of 150 ps. In order to reduce multiple scattering and hadronic interactions of beam particles, the material budget of a single GTK station has been fixed to 0.5% X0. The expected fluence for 100 days of running is 2 ×1014 1 MeV neq /cm2, comparable to the one foreseen in the inner trackers of LHC detectors during 10 years of operation. To comply with these requirements, an efficient and very low-mass (architectures have been produced as small-scale prototypes: one is based on a Time-over-Threshold circuit followed by a TDC shared by a group of pixels, while the other makes use of a constant-fraction discriminator followed by an on-pixel TDC. The read-out ASICs are produced in 130 nm IBM CMOS technology and will be thinned down to 100 μm or less. An overview of the Gigatracker detector system will be presented. Experimental results from laboratory and beam tests of prototype bump-bonded assemblies will be described as well. These results show a time resolution of about 170 ps for single hits from minimum ionizing particles, using 200 μm thick silicon sensors.

  2. High rate particle tracking and ultra-fast timing with a thin hybrid silicon pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Fiorini, M., E-mail: Massimiliano.Fiorini@cern.ch [CERN, CH-1211 Geneva 23 (Switzerland); Aglieri Rinella, G. [CERN, CH-1211 Geneva 23 (Switzerland); Carassiti, V. [INFN Sezione di Ferrara (Italy); Ceccucci, A. [CERN, CH-1211 Geneva 23 (Switzerland); Cortina Gil, E. [Université Catholique de Louvain, Louvain-la-Neuve (Belgium); Cotta Ramusino, A. [INFN Sezione di Ferrara (Italy); Dellacasa, G.; Garbolino, S.; Jarron, P. [INFN Sezione di Torino (Italy); Kaplon, J.; Kluge, A.; Marchetto, F.; Mapelli, A. [CERN, CH-1211 Geneva 23 (Switzerland); Martin, E. [Université Catholique de Louvain, Louvain-la-Neuve (Belgium); Mazza, G. [INFN Sezione di Torino (Italy); Morel, M.; Noy, M. [CERN, CH-1211 Geneva 23 (Switzerland); Nuessle, G. [Université Catholique de Louvain, Louvain-la-Neuve (Belgium); Perktold, L.; Petagna, P. [CERN, CH-1211 Geneva 23 (Switzerland); and others

    2013-08-01

    The Gigatracker (GTK) is a hybrid silicon pixel detector designed for the NA62 experiment at CERN. The beam spectrometer, made of three GTK stations, has to sustain high and non-uniform particle rate (∼1GHz in total) and measure momentum and angles of each beam track with a combined time resolution of 150 ps. In order to reduce multiple scattering and hadronic interactions of beam particles, the material budget of a single GTK station has been fixed to 0.5% X{sub 0}. The expected fluence for 100 days of running is 2×10{sup 14} 1 MeV n{sub eq}/cm{sup 2}, comparable to the one foreseen in the inner trackers of LHC detectors during 10 years of operation. To comply with these requirements, an efficient and very low-mass (<0.15%X{sub 0}) cooling system is being constructed, using a novel microchannel cooling silicon plate. Two complementary read-out architectures have been produced as small-scale prototypes: one is based on a Time-over-Threshold circuit followed by a TDC shared by a group of pixels, while the other makes use of a constant-fraction discriminator followed by an on-pixel TDC. The read-out ASICs are produced in 130 nm IBM CMOS technology and will be thinned down to 100μm or less. An overview of the Gigatracker detector system will be presented. Experimental results from laboratory and beam tests of prototype bump-bonded assemblies will be described as well. These results show a time resolution of about 170 ps for single hits from minimum ionizing particles, using 200μm thick silicon sensors.

  3. A test device for isotopic γ-ray imaging with CdZnTe detector

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A test device for isotopic γ-ray imaging, which consists of an isotope γ-ray source, a CdZnTe γ-ray spectrometer and other auxiliary equipment, is studied here. Compared with the conventional X-ray, the isotope γ-ray,which is utilized in this project, has its own advantages in imaging. Furthermore, with a room-temperature high-energy-resolution CdZnTe detector and a modern imaging processing technique, this device is capable of effectively suppressing the background and gaining more information, thus it can obtain a better image than conventional X-ray devices. In the experiment of PCB imaging, all soldered points and chip components are sharply demonstrated.

  4. LiF crystals as high spatial resolution neutron imaging detectors

    Energy Technology Data Exchange (ETDEWEB)

    Matsubayashi, M., E-mail: matsubayashi.masahito@jaea.go.jp [Quantum Beam Science Directorate, Japan Atomic Energy Agency, Shirane 2-4, Shirakata, Tokai, Ibaraki 319-1195 (Japan); Faenov, A.; Pikuz, T. [Joint Institute for High Temperatures of Russian Academy of Sciences, Izhorskaja Street 13/19, Moscow (Russian Federation); Fukuda, Y. [Kansai Photon Science Institute, Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215 (Japan); Kato, Y. [The Graduate School for the Creation of New Photonics Industries, Hamamatsu, Shizuoka 431-1202 (Japan); Yasuda, R.; Iikura, H.; Nojima, T.; Sakai, T. [Quantum Beam Science Directorate, Japan Atomic Energy Agency, Shirane 2-4, Shirakata, Tokai, Ibaraki 319-1195 (Japan)

    2011-09-21

    Neutron imaging by color center formation in LiF crystals was applied to a sensitivity indicator (SI) as a standard samples for neutron radiography. The SI was exposed to a 5 mm pinhole-collimated thermal neutron beam with an LiF crystal and a neutron imaging plate (NIP) for 120 min in the JRR-3M thermal neutron radiography facility. The image in the LiF crystal was read out using a laser confocal microscope. All gaps were clearly observed in images for both the LiF crystal and the NIP. The experimental results showed that LiF crystals have excellent characteristics as neutron imaging detectors in areas such as high spatial resolution.

  5. TSV last for hybrid pixel detectors: Application to particle physics and imaging experiments

    CERN Document Server

    Henry, D; Berthelot, A; Cuchet, R; Chantre, C; Campbell, M

    Hybrid pixel detectors are now widely used in particle physics experiments and at synchrotron light sources. They have also stimulated growing interest in other fields and, in particular, in medical imaging. Through the continuous pursuit of miniaturization in CMOS it has been possible to increase the functionality per pixel while maintaining or even shrinking pixel dimensions. The main constraint on the more extensive use of the technology in all fields is the cost of module building and the difficulty of covering large areas seamlessly [1]. On another hand, in the field of electronic component integration, a new approach has been developed in the last years, called 3D Integration. This concept, based on using the vertical axis for component integration, allows improving the global performance of complex systems. Thanks to this technology, the cost and the form factor of components could be decreased and the performance of the global system could be enhanced. In the field of radiation imaging detectors the a...

  6. Two-dimensional GEM imaging detector with delay-line readout

    Science.gov (United States)

    Guedes, G. P.; Breskin, A.; Chechik, R.; Vartsky, D.; Bar, D.; Barbosa, A. F.; Marinho, P. R. B.

    2003-11-01

    A 100×100 mm 2 2D imaging detector, based on a triple-GEM gaseous multiplier, striped x- y readout anode and discrete delay-line readout, is presented. The fast (2.1 ns tap -1) delay-line circuit was designed to match the anode-charge signal profile, namely its rise-time and length. The detector's imaging capability was systematically studied in Ar/CO 2 (70/30) with 5.9 keV X-rays; x- y resolution of σ=0.05 and 0.1 mm for top and bottom anode strips, respectively, and integral non-linearity of ˜0.15% are demonstrated.

  7. Non-invasive, near-field terahertz imaging of hidden objects using a single pixel detector

    CERN Document Server

    Stantchev, R I; Hornett, S M; Hobson, P A; Gibson, G M; Padgett, M J; Hendry, E

    2015-01-01

    Terahertz (THz) imaging has the ability to see through otherwise opaque materials. However, due to the long wavelengths of THz radiation ({\\lambda}=300{\\mu}m at 1THz), far-field THz imaging techniques are heavily outperformed by optical imaging in regards to the obtained resolution. In this work we demonstrate near-field THz imaging with a single-pixel detector. We project a time-varying optical mask onto a silicon wafer which is used to spatially modulate a pulse of THz radiation. The far-field transmission corresponding to each mask is recorded by a single element detector and this data is used to reconstruct the image of an object placed on the far side of the silicon wafer. We demonstrate a proof of principal application where we image a printed circuit board on the underside of a 115{\\mu}m thick silicon wafer with ~100{\\mu}m ({\\lambda}/4) resolution. With subwavelength resolution and the inherent sensitivity to local conductivity provided by the THz probe frequencies, we show that it is possible to detec...

  8. Performance of Drift-Tube Detectors at High Counting Rates for High-Luminosity LHC Upgrades

    CERN Document Server

    Bittner, Bernhard; Kortner, Oliver; Kroha, Hubert; Manfredini, Alessandro; Nowak, Sebastian; Ott, Sebastian; Richter, Robert; Schwegler, Philipp; Zanzi, Daniele; Biebel, Otmar; Hertenberger, Ralf; Ruschke, Alexander; Zibell, Andre

    2016-01-01

    The performance of pressurized drift-tube detectors at very high background rates has been studied at the Gamma Irradiation Facility (GIF) at CERN and in an intense 20 MeV proton beam at the Munich Van-der-Graaf tandem accelerator for applications in large-area precision muon tracking at high-luminosity upgrades of the Large Hadron Collider (LHC). The ATLAS muon drifttube (MDT) chambers with 30 mm tube diameter have been designed to cope with and neutron background hit rates of up to 500 Hz/square cm. Background rates of up to 14 kHz/square cm are expected at LHC upgrades. The test results with standard MDT readout electronics show that the reduction of the drift-tube diameter to 15 mm, while leaving the operating parameters unchanged, vastly increases the rate capability well beyond the requirements. The development of new small-diameter muon drift-tube (sMDT) chambers for LHC upgrades is completed. Further improvements of tracking e?ciency and spatial resolution at high counting rates will be achieved with ...

  9. Image processing analysis of nuclear track parameters for CR-39 detector irradiated by thermal neutron

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jobouri, Hussain A., E-mail: hahmed54@gmail.com; Rajab, Mustafa Y., E-mail: mostafaheete@gmail.com [Department of Physics, College of Science, AL-Nahrain University, Baghdad (Iraq)

    2016-03-25

    CR-39 detector which covered with boric acid (H{sub 3}Bo{sub 3}) pellet was irradiated by thermal neutrons from ({sup 241}Am - {sup 9}Be) source with activity 12Ci and neutron flux 10{sup 5} n. cm{sup −2}. s{sup −1}. The irradiation times -T{sub D} for detector were 4h, 8h, 16h and 24h. Chemical etching solution for detector was sodium hydroxide NaOH, 6.25N with 45 min etching time and 60 C° temperature. Images of CR-39 detector after chemical etching were taken from digital camera which connected from optical microscope. MATLAB software version 7.0 was used to image processing. The outputs of image processing of MATLAB software were analyzed and found the following relationships: (a) The irradiation time -T{sub D} has behavior linear relationships with following nuclear track parameters: i) total track number - N{sub T} ii) maximum track number - MRD (relative to track diameter - D{sub T}) at response region range 2.5 µm to 4 µm iii) maximum track number - M{sub D} (without depending on track diameter - D{sub T}). (b) The irradiation time -T{sub D} has behavior logarithmic relationship with maximum track number - M{sub A} (without depending on track area - A{sub T}). The image processing technique principally track diameter - D{sub T} can be take into account to classification of α-particle emitters, In addition to the contribution of these technique in preparation of nano- filters and nano-membrane in nanotechnology fields.

  10. A gas scintillation counter with imaging optics and large area UV-detector

    Energy Technology Data Exchange (ETDEWEB)

    Nickles, J. E-mail: nickles@hsb.uni-frankfurt.de; Braeuning, H.; Braeuning-Demian, A.; Dangendorf, V.; Breskin, A.; Chechik, R.; Rauschnabel, K.; Schmidt-Boecking, H

    2002-01-21

    We report on the improvements in the position sensitive readout of a xenon-filled gas scintillation proportional counter. Using an imaging optic for UV-light in the region of 170 nm, the position resolution could be improved by more than 30%. In addition, we have obtained first encouraging results for the use of the recently developed gas electron multiplier together with a CsI-photocathode as a large area UV-detector system.

  11. A gas scintillation counter with imaging optics and large area UV-detector

    CERN Document Server

    Nickles, J; Bräuning-Demian, A; Breskin, Amos; Chechik, R; Dangendorf, V; Rauschnabel, K; Schmidt-Böcking, H

    2002-01-01

    We report on the improvements in the position sensitive readout of a xenon-filled gas scintillation proportional counter. Using an imaging optic for UV-light in the region of 170 nm, the position resolution could be improved by more than 30%. In addition, we have obtained first encouraging results for the use of the recently developed gas electron multiplier together with a CsI-photocathode as a large area UV-detector system.

  12. Development of Fast High-Resolution Muon Drift-Tube Detectors for High Counting Rates

    CERN Document Server

    INSPIRE-00287945; Dubbert, J.; Horvat, S.; Kortner, O.; Kroha, H.; Legger, F.; Richter, R.; Adomeit, S.; Biebel, O.; Engl, A.; Hertenberger, R.; Rauscher, F.; Zibell, A.

    2011-01-01

    Pressurized drift-tube chambers are e?cient detectors for high-precision tracking over large areas. The Monitored Drift-Tube (MDT) chambers of the muon spectrometer of the ATLAS detector at the Large Hadron Collider (LHC) reach a spatial resolution of 35 micons and almost 100% tracking e?ciency with 6 layers of 30 mm diameter drift tubes operated with Ar:CO2 (93:7) gas mixture at 3 bar and a gas gain of 20000. The ATLAS MDT chambers are designed to cope with background counting rates due to neutrons and gamma-rays of up to about 300 kHz per tube which will be exceeded for LHC luminosities larger than the design value of 10-34 per square cm and second. Decreasing the drift-tube diameter to 15 mm while keeping the other parameters, including the gas gain, unchanged reduces the maximum drift time from about 700 ns to 200 ns and the drift-tube occupancy by a factor of 7. New drift-tube chambers for the endcap regions of the ATLAS muon spectrometer have been designed. A prototype chamber consisting of 12 times 8 l...

  13. Upper limits from the LIGO and TAMA detectors on the rate of gravitational-wave bursts

    CERN Document Server

    Abbott, B; Adhikari, R; Ageev, A; Agresti, J; Akutsu, T; Allen, B; Allen, J; Amin, R; Anderson, S B; Anderson, W G; Ando, M; Arai, K; Araya, A; Araya, M; Armandula, H; Asada, H; Ashley, M; Asiri, F; Aso, Y; Aufmuth, P; Aulbert, C; Babak, S; Balasubramanian, R; Ballmer, S; Barish, B C; Barker, C; Barker, D; Barnes, M; Barr, B; Barton, M A; Bayer, K; Beausoleil, R; Belczynski, K; Bennett, R; Berukoff, S J; Betzwieser, J; Beyersdorf, P; Bhawal, B; Bilenko, I A; Billingsley, G; Black, E; Blackburn, K; Blackburn, L; Bland, B; Bochner, B; Bogue, L; Bork, R; Bose, S; Brady, P R; Braginsky, V B; Brau, J E; Brown, D A; Bullington, A; Bunkowski, A; Buonanno, A; Burgess, R; Busby, D; Butler, W E; Byer, R L; Cadonati, L; Cagnoli, G; Camp, J B; Cannizzo, J; Cannon, K; Cantley, C A; Cardenas, L; Carter, K; Casey, M M; Castiglione, J; Chandler, A; Chapsky, J; Charlton, P; Chatterji, S; Chelkowski, S; Chen, Y; Chickarmane, V; Chin, D; Christensen, N; Churches, D; Cokelaer, T; Colacino, C; Coldwell, R; Coles, M; Cook, D; Corbitt, T; Coyne, D; Creighton, J D E; Creighton, T D; Crooks, D R M; Csatorday, P; Cusack, B J; Cutler, C; D'Ambrosio, E; Dalrymple, J; Danzmann, K; Davies, G; Daw, E; De Bra, D; DeSalvo, R; Delker, T; Dergachev, V; Desai, S; Dhurandhar, S V; Di Credico, A; Ding, H; Drever, R W P; Dupuis, R J; Edlund, J A; Ehrens, P; Elliffe, E J; Etzel, T; Evans, M; Evans, T; Fairhurst, S; Fallnich, C; Farnham, D; Fejer, M M; Findley, T; Fine, M; Finn, L S; Franzen, K Y; Freise, A; Frey, R; Fritschel, P; Frolov, V V; Fujiki, Y; Fujimoto, M K; Fujita, R; Fukushima, M; Futamase, T; Fyffe, M; Ganezer, K S; Garofoli, J; Giaime, J A; Gillespie, A; Goda, K; Goggin, L; Goler, S; González, G; Grandclément, P; Grant, A; Gray, C; Gretarsson, A M; Grimmett, D; Grote, H; Grünewald, S; Gustafson, E; Gustafson, R; Günther, M; Hamilton, W O; Hammond, M; Hamuro, Y; Hanson, J; Hardham, C; Harms, J; Harry, G; Hartunian, A; Haruyama, T; Hayama, K; Heefner, J; Hefetz, Y; Heinzel, G; Heng, I S; Hennessy, M; Hepler, N; Heptonstall, A; Heurs, M; Hewitson, M; Hild, S; Hindman, N; Hoang, P; Hough, J; Hrynevych, M; Hua, W; Iguchi, H; Iida, Y; Ioka, K; Ishizuka, H; Ito, M; Itoh, Y; Ivanov, A; Jennrich, O; Johnson, B; Johnson, W W; Johnston, W R; Jones, D I; Jones, G; Jones, L; Jungwirth, D; Kalogera, V; Kamikubota, N; Kanda, N; Kaneyama, T; Karasawa, Y; Kasahara, K; Kasai, T; Katsavounidis, E; Katsuki, M; Kawabe, K; Kawamura, M; Kawamura, S; Kawazoe, F; Kells, W; Kern, J; Khan, A; Killbourn, S; Killow, C J; Kim, C; King, C; King, P; Klimenko, S; Kojima, Y; Kokeyama, K; Kondo, K; Koranda, S; Kotter, K; Kovalik, Yu; Kozai, Y; Kozak, D; Krishnan, B; Kudo, H; Kuroda, K; Kuwabara, T; Landry, M; Langdale, J; Lantz, B; Lawrence, R; Lazzarini, A; Lei, M; Leonor, I; Libbrecht, K; Libson, A; Lindquist, P; Liu, S; Logan, J; Lormand, M; Lubinski, M; Luck, H; Luna, M; Lyons, T T; MacInnis, M; Machenschalk, B; Mageswaran, M; Mailand, K; Majid, W; Malec, M; Mandic, V; Mann, F; Marin, A; Marka, S; Maros, E; Mason, J; Mason, K; Matherny, O; Matone, L; Matsuda, N; Mavalvala, N; McCarthy, R; McClelland, D E; McHugh, M; McNabb, J W C; Melissinos, A C; Mendell, G; Mercer, R A; Meshkov, S; Messaritaki, E; Messenger, C; Mikhailov, E; Mio, N; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Miura, K; Miyakawa, O; Miyama, S; Miyoki, S; Mizusawa, H; Mohanty, S; Moreno, G; Moriwaki, S; Mossavi, K; Mukherjee, S; Murray, P; Musha, M; Myers, E; Myers, J; Müller, G; Nagano, S; Nagayama, Y; Nakagawa, K; Nakamura, T; Nakano, H; Nakao, K; Nash, T; Nayak, R; Newton, G; Nishi, Y; Nocera, F; Noel, J S; Numata, K; Nutzman, P; O'Reilly, B; Ogawa, Y; Ohashi, M; Ohishi, N; Okutomi, A; Olson, T; Oohara, K; Otsuka, S; Ottaway, D J; Ottewill, A; Ouimette, D A; Overmier, H; Owen, B J; Pan, Y; Papa, M A; Parameshwaraiah, V; Parameswaran, A J; Parameswariah, C; Pedraza, M; Penn, S; Pitkin, M; Plissi, M; Prix, R; Quetschke, V; Raab, F; Radkins, H; Rahkola, R; Rakhmanov, M; Rao, S R; Rawlins, K; Ray-Majumder, S; Re, V; Redding, D; Regehr, M W; Regimbau, T; Reid, S; Reilly, K T; Reithmaier, K; Reitze, D H; Richman, S; Riesen, R; Riles, K; Rivera, B; Rizzi, A; Robertson, D I; Robertson, N A; Robinson, C; Robison, L; Roddy, S; Rodríguez, A; Rollins, J; Romano, J D; Romie, J; Rong, H; Rose, D; Rotthoff, E; Rowan, S; Ruet, L; Russell, P; Ryan, K; Rüdiger, A; Saitô, Y; Sakata, S; Salzman, I; Sandberg, V; Sanders, G H; Sannibale, V; Sarin, P; Sasaki, M; Sathyaprakash, B; Sato, K; Sato, N; Sato, S; Sato, Y; Saulson, P R; Savage, R; Sazonov, A; Schilling, R; Schlaufman, K; Schmidt, V; Schnabel, R; Schofield, R; Schutz, B F; Schwinberg, P; Scott, S M; Seader, S E; Searle, A C; Sears, B; Seel, S; Seifert, F; Sekido, A; Sellers, D; Sengupta, A S; Seto, N; Shapiro, C A; Shawhan, P; Shibata, M; Shinkai, H; Shintomi, T; Shoemaker, D H; Shu, Q Z; Sibley, A; Siemens, X; Sievers, L; Sigg, D; Sintes, A M; Smith, J R; Smith, M; Smith, M R; Sneddon, P H; Soida, K; Somiya, K; Spero, R; Spjeld, O; Stapfer, G; Steussy, D; Strain, K A; Strom, D; Stuver, A; Summerscales, T; Sumner, M C; Sung, M; Sutton, P J; Suzuki, T; Sylvestre, J; Tagoshi, H; Takahashi, H; Takahashi, R; Takamori, A; Takemoto, S; Takeno, K; Tanaka, T; Taniguchi, K; Tanji, T; Tanner, D B; Tariq, H; Tatsumi, D; Taylor, I; Taylor, R; Telada, S; Thorne, K A; Thorne, K S; Tibbits, M; Tilav, S; Tinto, M; Tokmakov, K V; Tokunari, M; Tomaru, T; Torres, C; Torrie, C; Traylor, G; Tsubono, K; Tsuda, N; Tsunesada, Y; Tyler, W; Uchiyama, T; Ueda, A; Ueda, K; Ugolini, D W; Ungarelli, C; Vallisneri, M; Van Putten, M H P M; Vass, S; Vecchio, A; Veitch, J; Vorvick, C; Vyachanin, S P; Wallace, L; Walther, H; Ward, H; Ward, R; Ware, B; Waseda, K; Watts, K; Webber, D; Weidner, A; Weiland, U; Weinstein, A; Weiss, R; Welling, H; Wen, L; Wen, S; Wette, K; Whelan, J T; Whitcomb, S E; Whiting, B F; Wiley, S; Wilkinson, C; Willems, P A; Williams, P R; Williams, R; Willke, B; Wilson, A; Winjum, B J; Winkler, W; Wise, S; Wiseman, A G; Woan, G; Woods, D; Wooley, R; Worden, J; Wu, W; Yakushin, I; Yamamoto, A; Yamamoto, H; Yamamoto, K; Yamazaki, T; Yanagi, Y; Yokoyama, J; Yoshida, S; Yoshida, T; Zaleski, K D; Zanolin, M; Zawischa, I; Zhang, L; Zhu, R; Zhu, Z H; Zotov, N P; Zucker, M; Zweizig, J

    2005-01-01

    We report on the first joint search for gravitational waves by the TAMA and LIGO collaborations. We looked for millisecond-duration unmodelled gravitational-wave bursts in 473 hr of coincident data collected during early 2003. No candidate signals were found. We set an upper limit of 0.12 events per day on the rate of detectable gravitational-wave bursts, at 90% confidence level. From simulations, we estimate that our detector network was sensitive to bursts with root-sum-square strain amplitude above approximately 1-3x10^{-19} Hz^{-1/2} in the frequency band 700-2000 Hz. We describe the details of this collaborative search, with particular emphasis on its advantages and disadvantages compared to searches by LIGO and TAMA separately using the same data. Benefits include a lower background and longer observation time, at some cost in sensitivity and bandwidth. We also demonstrate techniques for performing coincidence searches with a heterogeneous network of detectors with different noise spectra and orientatio...

  14. Extended Measurement Capabilities of the Electron Proton Helium INstrument aboard SOHO - Understanding single detector count rates

    Science.gov (United States)

    Kühl, P.; Banjac, S.; Heber, B.; Labrenz, J.; Müller-Mellin, R.; Terasa, C.

    Forbush (1937) was the first to observe intensity decreases lasting for a few days utilizing ionization chambers. A number of studies on Forbush decreases (FDs) have been performed since then utilizing neutron monitors and space instrumentation. The amplitude of these variations can be as low as a few permil. Therefore intensity measurements need to be of high statistical accuracy. Richardson et al. (1996) suggested therefore to utilize the single counter measurements of the guard counters of the IMP 8 and Helios E6 instruments. Like the above mentioned instruments the Electron Proton Helium INstrument (EPHIN) provides single counting rates. During the extended solar minimum in 2009 its guard detector counted about 25000~counts/minute, allowing to determine intensity variations of less than 2 permil using 30 minute averages. We performed a GEANT 4 simulation of the instrument in order to determine the energy response of all single detectors. It is shown here that their energy thresholds are much lower than the ones of neutron monitors and therefore we developed a criterion that allows to investigate FDs during quiet time periods.

  15. Trade off study on different envelope detectors for B-mode imaging

    DEFF Research Database (Denmark)

    Schlaikjer, Malene; Bagge, J. P.; Jensen, Jørgen Arendt

    2003-01-01

    Generation of B-mode images involves envelope detection of the RF-signals. Various detection algorithms are available. A trade off between performance, price, and complexity determines the choice of algorithm in an ultrasound system. A Hilbert Transform (HT) and a subsequent computation of the ma......Generation of B-mode images involves envelope detection of the RF-signals. Various detection algorithms are available. A trade off between performance, price, and complexity determines the choice of algorithm in an ultrasound system. A Hilbert Transform (HT) and a subsequent computation...... of the magnitude give the ideal envelope, but the approach (IDE) is expensive and complex. A rectifier (REC) is a simple, low-cost solution, but the performance is severely degraded (especially in dynamic imaging). This study has investigated the possibility of providing a detector with a complexity and cost close...... to REC, while maintaining a performance close to IDE. Two low-cost detectors have been implemented and evaluated on in-vivo data. The first approach is an expansion of the rectifier with a median filter (ERM). The second detector (TAS) approximates the HT by a time delay and the magnitude by a weighted...

  16. Chromium compensated gallium arsenide detectors for X-ray and γ-ray spectroscopic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Veale, M.C., E-mail: matthew.veale@stfc.ac.uk [Rutherford Appleton Laboratory, Science and Technology Facilities Council, OX11 0QX (United Kingdom); Bell, S.J.; Duarte, D.D. [Rutherford Appleton Laboratory, Science and Technology Facilities Council, OX11 0QX (United Kingdom); Faculty of Engineering and Physical Sciences, University of Surrey, GU2 7XH (United Kingdom); French, M.J.; Schneider, A.; Seller, P.; Wilson, M.D. [Rutherford Appleton Laboratory, Science and Technology Facilities Council, OX11 0QX (United Kingdom); Lozinskaya, A.D.; Novikov, V.A.; Tolbanov, O.P.; Tyazhev, A.; Zarubin, A.N. [Siberian Physical–Technical Institute of Tomsk State University, Tomsk (Russian Federation)

    2014-07-01

    Semi-insulating GaAs material of 500 μm thickness grown using the Liquid Encapsulated Czochralski (LEC) method has been compensated with chromium to produce high resistivity single crystals suitable for spectroscopic imaging applications. Results are presented for the performance of three small pixel detectors each with 80×80 pixels on a 250 μm pitch, fabricated with metal contacts and bonded to a spectroscopic imaging ASIC. Current–voltage measurements demonstrated a material resistivity of 2.5×10{sup 9} Ω cm at room temperature. At an optimised bias voltage, the average energy resolution at 60 keV (FWHM) was in the range 2.8–3.3 keV per pixel. An analysis of the voltage dependent X-ray spectroscopy suggests that the electron mobility lifetime (μτ{sub e}) for each detector is in the range 2.1–4.5×10{sup −5} cm{sup 2} V{sup −1}. The spectroscopic imaging capability of the detectors is also demonstrated in X-ray absorption spectroscopy measurements.

  17. Two-dimensional, single-photoelectron drift detector for Cherenkov ring imaging

    Energy Technology Data Exchange (ETDEWEB)

    Barrelet, E.; Seguinot, J.; Urban, M.; Ypsilantis, T. (Ecole Polytechnique, 91 - Palaiseau (France)); Ekeloef, T. (European Organization for Nuclear Research, Geneva (Switzerland)); Lund-Jensen, B. (Uppsala Univ. (Sweden)); Tocqueville, J. (College de France, 75 - Paris)

    1982-09-15

    A detector capable of imaging single photoelectrons has been constructed and tested. UV photons (>=5.4 eV) are converted to electrons with high quantum efficiency by photoionization of a small admixture (approx. equal to 1 Torr) of an organic vapour TMAE in a predominantly methane drift and amplifying gas at atmospheric pressure. The produced photoelectrons drift in a uniform applied electric field to a picket fence of proportional wires where each electron is amplified, counted and timed. The two-dimensional source point of each photoelectron is uniquely determined by the hit wire address and the arrival time. The detector has been tested by measuring ionization electrons produced in the drift gas be relativistic charged particles. The limiting precision to which the electron source point can be determined has been measured to be 300 ..mu..m (r.m.s.) in the drift direction and 370 ..mu..m in the wire plane direction. Additional independent error sources due to electron diffusion in the drift gas have been measured to be proportional to the square root of the drift distance with a proportionality constant of 235 ..mu..m/cmsup(1/2) in both directions. Drift velocities of electrons in various predominantly methane gas mixtures have been measured as a function of the applied electric field. The utilization of such a two-dimensional single electron drift detector for Cherenkov ring imaging is presented with a discussion of the advantages and limitations of the drift method for imaging.

  18. Image quality of a digital chest radiography system based on a selenium detector.

    Science.gov (United States)

    Neitzel, U; Maack, I; Günther-Kohfahl, S

    1994-04-01

    A digital chest radiography system has been developed, with a detector based on the photoelectric properties of amorphous selenium. The selenium layer is deposited on a cylindrical aluminium drum, large enough to cover the full field of view for chest imaging. The electrostatic charge image which is formed on the selenium surface after x-ray exposure is read out by electrometer probes using fast drum rotation. For a physical evaluation of the attainable image quality, the characteristic curve, the modulation transfer function, and the noise spectra were measured. From these measurements, the signal-to-noise properties of the detector in terms of detective quantum efficiency (DQE) and noise equivalent quanta (NEQ) were derived. The results show that the selenium-based detector has a wide dynamic range and a significantly better DQE than screen-film and storage phosphor systems for spatial frequencies below the Nyquist limit (2.7 lp/mm). As a consequence, the detectability of small, low-contrast details is considerably improved.

  19. 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.

  20. a SAR Intensity Images Change Detection Method Based on Fusion Difference Detector and Statistical Properties

    Science.gov (United States)

    Cui, B.; Zhang, Y.; Yan, L.; Cai, X.

    2017-09-01

    Detecting the land cover changes is an important application of multi-temporal synthetic aperture radar (SAR) images. This study puts forward a novel SAR change detection method which has two-steps: change detector construction and change threshold selection. For change detector construction, considering the SAR intensity images follow the gamma distribution, the conditional probabilities of the binary hypothesis test are provided, then the log likelihood ratio (LLR) combined with the log ratio (LR) to construct a detector which can enhance the degree of change to calculate the diversity degree convenient between the two images; for change threshold selection, owing to the characteristic that the curve about the ratio value of adjacent grey-level (GL) values in normalized difference map, the normalized difference map can be segmented in three parts by two thresholds selected which correspond to the regions of unchanged, backscatter enhanced and weakened separately. And as this, the change areas can be also determined simultaneously. The experimental results on different areas and sensors indicate that the proposed algorithm is effective and feasible.

  1. Cone-beam CT with a flat-panel detector: From image science to image-guided surgery

    Energy Technology Data Exchange (ETDEWEB)

    Siewerdsen, Jeffrey H., E-mail: jeff.siewerdsen@jhu.edu [Department of Biomedical Engineering, Johns Hopkins University, Traylor Building, Room 718, 720 Rutland Avenue, Baltimore, MD 21205 (United States)

    2011-08-21

    The development of large-area flat-panel X-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of the Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions-for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck/skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in surgical

  2. Cone-beam CT with a flat-panel detector: From image science to image-guided surgery

    Science.gov (United States)

    Siewerdsen, Jeffrey H.

    2011-08-01

    The development of large-area flat-panel X-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of the Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions—for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck/skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in

  3. Full-Color Computational Imaging with Single-Pixel Detectors Based on a 2D Discrete Cosine Transform

    CERN Document Server

    Liu, Bao-Lei; Wu, Ling-An

    2016-01-01

    We propose and demonstrate a computational imaging technique that uses structured illumination based on a two-dimensional discrete cosine transform to perform imaging with a single-pixel detector. A scene is illuminated by a projector with two sets of orthogonal patterns, then by applying an inverse cosine transform to the spectra obtained from the single-pixel detector a full-color image is retrieved. This technique can retrieve an image from sub-Nyquist measurements, and the background noise is easily canceled to give excellent image quality. Moreover, the experimental setup is very simple.

  4. Medical image reconstruction algorithm based on the geometric information between sensor detector and ROI

    Science.gov (United States)

    Ham, Woonchul; Song, Chulgyu; Lee, Kangsan; Roh, Seungkuk

    2016-05-01

    In this paper, we propose a new image reconstruction algorithm considering the geometric information of acoustic sources and senor detector and review the two-step reconstruction algorithm which was previously proposed based on the geometrical information of ROI(region of interest) considering the finite size of acoustic sensor element. In a new image reconstruction algorithm, not only mathematical analysis is very simple but also its software implementation is very easy because we don't need to use the FFT. We verify the effectiveness of the proposed reconstruction algorithm by showing the simulation results by using Matlab k-wave toolkit.

  5. The design and imaging characteristics of dynamic, solid-state, flat-panel x-ray image detectors for digital fluoroscopy and fluorography.

    Science.gov (United States)

    Cowen, A R; Davies, A G; Sivananthan, M U

    2008-10-01

    Dynamic, flat-panel, solid-state, x-ray image detectors for use in digital fluoroscopy and fluorography emerged at the turn of the millennium. This new generation of dynamic detectors utilize a thin layer of x-ray absorptive material superimposed upon an electronic active matrix array fabricated in a film of hydrogenated amorphous silicon (a-Si:H). Dynamic solid-state detectors come in two basic designs, the indirect-conversion (x-ray scintillator based) and the direct-conversion (x-ray photoconductor based). This review explains the underlying principles and enabling technologies associated with these detector designs, and evaluates their physical imaging characteristics, comparing their performance against the long established x-ray image intensifier television (TV) system. Solid-state detectors afford a number of physical imaging benefits compared with the latter. These include zero geometrical distortion and vignetting, immunity from blooming at exposure highlights and negligible contrast loss (due to internal scatter). They also exhibit a wider dynamic range and maintain higher spatial resolution when imaging over larger fields of view. The detective quantum efficiency of indirect-conversion, dynamic, solid-state detectors is superior to that of both x-ray image intensifier TV systems and direct-conversion detectors. Dynamic solid-state detectors are playing a burgeoning role in fluoroscopy-guided diagnosis and intervention, leading to the displacement of x-ray image intensifier TV-based systems. Future trends in dynamic, solid-state, digital fluoroscopy detectors are also briefly considered. These include the growth in associated three-dimensional (3D) visualization techniques and potential improvements in dynamic detector design.

  6. Dose-rate effects on the bulk etch-rate of CR-39 track detector exposed to low-LET radiations

    CERN Document Server

    Yamauchi, T; Oda, K; Ikeda, T; Honda, Y; Tagawa, S

    1999-01-01

    The effect of gamma-rays and pulsed electrons has been investigated on the bulk etch rate of CR-39 detector at doses up to 100 kGy under various dose-rate between 0.0044 and 35.0 Gy/s. The bulk etch rate increased exponentially with the dose at every examined dose-rates. It was reveled to be strongly depend on the dose-rate: the bulk etch rate was decreased with increasing dose-rate at the same total dose. A primitive model was proposed to explain the dose-rate effect in which oxygen dissolved was assumed to dominate the damage formation process.

  7. Biological Tissue Imaging with a Position and Time Sensitive Pixelated Detector

    CERN Document Server

    Jungmann, Julia H; MacAleese, Luke; Klinkert, Ivo; Visser, Jan; Heeren, Ron M A

    2013-01-01

    We demonstrate the capabilities of a highly parallel, active pixel detector for large-area, mass spectrometric imaging of biological tissue sections. A bare Timepix assembly (512x512 pixels) is combined with chevron microchannel plates on an ion microscope matrix-assisted laser desorption time-of-flight mass spectrometer (MALDI TOF-MS). The detector assembly registers position- and time-resolved images of multiple m/z species in every measurement frame. We prove the applicability of the detection system to bio-molecular mass spectrometry imaging on biologically relevant samples by mass-resolved images from Timepix measurements of a peptide-grid benchmark sample and mouse testis tissue slices. Mass-spectral and localization information of analytes at physiological concentrations are measured in MALDI-TOF-MS imaging experiments. We show a high spatial resolution (pixel size down to 740x740 nm2 on the sample surface) and a spatial resolving power of 6 {\\mu}m with a microscope mode laser field of view of 100-335 ...

  8. Energy resolution of a silicon detector with the RX64 ASIC designed for X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bollini, D.; Cabal Rodriguez, A.E.; Dabrowski, W.; Diaz Garcia, A.; Gambaccini, M.; Giubellino, P.; Grybos, P.; Idzik, M.; Marzari-Chiesa, A.; Montano, L.M.; Prino, F.; Ramello, L. E-mail: ramello@to.infn.it; Sitta, M.; Swientek, K.; Wheadon, R.; Wiacek, P

    2003-12-11

    Results from a silicon microstrip detector coupled to the RX64 ASIC are presented. The system is capable of single photon counting in digital X-ray imaging, with foreseen applications to dual energy mammography and angiography. The main features of the detecting system are low noise (operation with threshold as low as {approx}4 keV is possible), good spatial resolution (a pixel of 100 {mu}mx300 {mu}m when oriented edge-on) and good counting rate capability (up to one million counts per channel with a maximum rate of about 200 kHz per channel). The energy resolution of the system, as obtained with several fluorescence X-ray lines, is described.

  9. TU-G-207-01: CT Imaging Using Energy-Sensitive Photon-Counting Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, K. [Johns Hopkins University (United States)

    2015-06-15

    Last few years has witnessed the development of novel of X-ray imaging modalities, such as spectral CT, phase contrast CT, and X-ray acoustic/fluorescence/luminescence imaging. This symposium will present the recent advances of these emerging X-ray imaging modalities and update the attendees with knowledge in various related topics, including X-ray photon-counting detectors, X-ray physics underlying the emerging applications beyond the traditional X-ray imaging, image reconstruction for the novel modalities, characterization and evaluation of the systems, and their practical implications. In addition, the concept and practical aspects of X-ray activatable targeted nanoparticles for molecular X-ray imaging will be discussed in the context of X-ray fluorescence and luminescence CT. Learning Objectives: Present background knowledge of various emerging X-ray imaging techniques, such as spectral CT, phase contrast CT and X-ray fluorescence/luminescence CT. Discuss the practical need, technical aspects and current status of the emerging X-ray imaging modalities. Describe utility and future impact of the new generation of X-ray imaging applications.

  10. Using Hierarchical Adaptive Neuro Fuzzy Systems And Design Two New Edge Detectors In Noisy Images

    Directory of Open Access Journals (Sweden)

    M. H. Olyaee

    2013-10-01

    Full Text Available One of the most important topics in image processing is edge detection. Many methods have been proposed for this end but most of them have weak performance in noisy images because noise pixels are determined as edge. In this paper, two new methods are represented based on Hierarchical Adaptive Neuro Fuzzy Systems (HANFIS. Each method consists of desired number of HANFIS operators that receive the value of some neighbouring pixels and decide central pixel is edge or not. Simple train images are used in order to set internal parameters of each HANFIS operator. The presented methods are evaluated by some test images and compared with several popular edge detectors. The experimental results show that these methods are robust against impulse noise and extract edge pixels exactly.

  11. Rotationally symmetric triangulation sensor with integrated object imaging using only one 2D detector

    Science.gov (United States)

    Eckstein, Johannes; Lei, Wang; Becker, Jonathan; Jun, Gao; Ott, Peter

    2006-04-01

    In this paper a distance measurement sensor is introduced, equipped with two integrated optical systems, the first one for rotationally symmetric triangulation and the second one for imaging the object while using only one 2D detector for both purposes. Rotationally symmetric triangulation, introduced in [1], eliminates some disadvantages of classical triangulation sensors, especially at steps or strong curvatures of the object, wherefore the measurement result depends not any longer on the angular orientation of the sensor. This is achieved by imaging the scattered light from an illuminated object point to a centered and sharp ring on a low cost area detector. The diameter of the ring is proportional to the distance of the object. The optical system consists of two off axis aspheric reflecting surfaces. This system allows for integrating a second optical system in order to capture images of the object at the same 2D detector. A mock-up was realized for the first time which consists of the reflecting optics for triangulation manufactured by diamond turning. A commercially available appropriate small lens system for imaging was mechanically integrated in the reflecting optics. Alternatively, some designs of retrofocus lens system for larger field of views were investigated. The optical designs allow overlying the image of the object and the ring for distance measurement in the same plane. In this plane a CCD detector is mounted, centered to the optical axis for both channels. A fast algorithm for the evaluation of the ring is implemented. The characteristics, i.e. the ring diameter versus object distance shows very linear behavior. For illumination of the object point for distance measurement, the beam of a red laser diode system is reflected by a wavelength bandpath filter on the axis of the optical system in. Additionally, the surface of the object is illuminated by LED's in the green spectrum. The LED's are located on the outside rim of the reflecting optics. The

  12. New pixelized Micromegas detector with low discharge rate for the COMPASS experiment

    CERN Document Server

    Neyret, D.; Anfreville, M.; Bedfer, Y.; Burtin, E.; Coquelet, C.; d'Hose, N.; Desforge, D.; Giganon, A.; Jourde, D.; Kunne, F.; Magnon, A.; Makke, N.; Marchand, C.; Paul, B.; Platchkov, S.; Thibaud, F.; Usseglio, M.; Vandenbroucke, M.

    2012-01-01

    New Micromegas (Micro-mesh gaseous detectors) are being developed in view of the future physics projects planned by the COMPASS collaboration at CERN. Several major upgrades compared to present detectors are being studied: detectors standing five times higher luminosity with hadron beams, detection of beam particles (flux up to a few hundred of kHz/mm^{2}, 10 times larger than for the present Micromegas detectors) with pixelized read-out in the central part, light and integrated electronics, and improved robustness. Two solutions of reduction of discharge impact have been studied, with Micromegas detectors using resistive layers and using an additional GEM foil. Performance of such detectors has also been measured. A large size prototypes with nominal active area and pixelized read-out has been produced and installed at COMPASS in 2010. In 2011 prototypes featuring an additional GEM foil, as well as an resistive prototype, are installed at COMPASS and preliminary results from those detectors presented very go...

  13. A new design of the gaseous imaging detector: Micro Pixel Chamber

    CERN Document Server

    Ochi, A; Koishi, S; Tanimori, T; Nagae, T; Nakamura, M

    2001-01-01

    The novel gaseous detector 'Micro Pixel Chamber (Micro PIC)' has been developed for X-ray, gamma-ray and charged particle imaging. This detector consists of double sided printing circuit board (PCB). The stable operation of Micro PIC is realized by thick substrate and wide anode strips. One of the most outstanding feature is the process of production and the cost. The base technology of producing Micro PIC is same as producing PCB, then detector with large detection area (more than 10 cmx10 cm) can be made by present technology. Our first tests were performed using a 3 cmx3 cm detection area with a readout of 0.4 mm pitch. The gas gain and stability were measured in these tests. The gas gain of 10 sup 4 was obtained using argon ethane (8:2) gas mixture. Also, there was no discharge between anodes and cathodes in the gain of 10 sup 3 during two days of continuous operation. Although some discharges occurred in the higher gain (approximately 10 sup 4), no critical damage on the detector was found.

  14. A practical method for randoms subtraction in volume imaging PET from detector singles countrate measurements

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.J.; Karp, J.S. [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Radiology

    1996-06-01

    Randoms subtraction in a volume imaging PET scanner is a significant problem due to the high singles countrates experienced. The delayed coincidence method requires double counting of randoms events and results in a lowered countrate capability. Calculations based on detector singles countrates require complex corrections for countrate dependent livetime and event acceptance due to the camera coincidence processing between the detector and rebinned randoms countrates. The profile distribution method has been used to estimate and subtract both scatter and randoms background but this method is a compromise and couples these 2 sources of background together. In order to avoid these problems and provide accurate subtraction of both the distribution and magnitude of randoms contamination in the scan data the authors have developed an alternative singles based method. The singles distributions are measured across the detectors and are used to construct a randoms distribution sinogram. This distribution is scaled to the appropriate rebinned randoms countrate by means of a lookup table of randoms countrate vs detector singles countrate, generated from phantom calibrations. The advantages of performing randoms subtraction by this method are: (1) there is no increase in camera deadtime, (2) the method compensates for nonuniformities in randoms distributions due to both the activity distribution and nonuniform geometric response of the camera for on and off bankpairs, and (3) it deals with randoms subtraction independently of scatter so that different scatter correction routines may then be applied to the data.

  15. Fundamental Limits on the Imaging and Polarisation Properties of Far-Infrared Detectors

    Science.gov (United States)

    Thomas, Christopher N.; Withington, Stafford; Chuss, David T.; Wollack, Edward J.; Moseley, S. Harvey

    2009-01-01

    Far-infrared bolometric detectors are used extensively in ground-based and space-borne astronomy, and thus it is important to understand their optical behaviour precisely. We have studied the intensity and polarisation response of free-space bolometers, and shown that when the size of the absorber is reduced below a wavelength, the response changes from being that of a classical optical detector to that of a few-mode antenna. We have calculated the modal content of the reception patterns, and found that for any volumetric detector having a side length of less than a wavelength, three magnetic and three electric dipoles characterize the behaviour. The size of the absorber merely determines the relative strengths of the contributions. The same formalism can be applied to thin-film absorbers, where the induced current is forced to flow in a plane. In this case, one magnetic and two electric dipoles characterize the behaviour. The ability to model easily the intensity, polarisation, and straylight characteristics of electrically-small detectors will be of great value when designing high-performance polarimetric imaging arrays.

  16. Comparison of ring artifact removal methods using flat panel detector based CT images

    Directory of Open Access Journals (Sweden)

    Lee Soo Y

    2011-08-01

    Full Text Available Abstract Background Ring artifacts are the concentric rings superimposed on the tomographic images often caused by the defective and insufficient calibrated detector elements as well as by the damaged scintillator crystals of the flat panel detector. It may be also generated by objects attenuating X-rays very differently in different projection direction. Ring artifact reduction techniques so far reported in the literature can be broadly classified into two groups. One category of the approaches is based on the sinogram processing also known as the pre-processing techniques and the other category of techniques perform processing on the 2-D reconstructed images, recognized as the post-processing techniques in the literature. The strength and weakness of these categories of approaches are yet to be explored from a common platform. Method In this paper, a comparative study of the two categories of ring artifact reduction techniques basically designed for the multi-slice CT instruments is presented from a common platform. For comparison, two representative algorithms from each of the two categories are selected from the published literature. A very recently reported state-of-the-art sinogram domain ring artifact correction method that classifies the ring artifacts according to their strength and then corrects the artifacts using class adaptive correction schemes is also included in this comparative study. The first sinogram domain correction method uses a wavelet based technique to detect the corrupted pixels and then using a simple linear interpolation technique estimates the responses of the bad pixels. The second sinogram based correction method performs all the filtering operations in the transform domain, i.e., in the wavelet and Fourier domain. On the other hand, the two post-processing based correction techniques actually operate on the polar transform domain of the reconstructed CT images. The first method extracts the ring artifact template

  17. Performance of a compact position-sensitive photon counting detector with image charge coupling to an air-side anode

    Science.gov (United States)

    Jagutzki, O.; Czasch, A.; Schössler, S.

    2013-05-01

    We discuss a novel micro-channel plate (MCP) photomultiplier with resistive screen (RS-PMT) as a detection device for space- and time-correlated single photon counting, illustrated by several applications. The photomultiplier tube resembles a standard image intensifier device. However, the rear phosphor screen is replaced by a ceramic "window" with resistive coating. The MCP output is transferred through the ceramic plate to the read-out electrode (on the air side) via capacity-coupling of the image charge. This design allows for an easy reconfiguration of the read-out electrode (e.g. pixel, charge-sharing, cross-strip, delay-line) without breaking the vacuum for optimizing the detector performance towards a certain task. It also eases the design and manufacturing process of such a multi-purpose photomultiplier tube. Temporal and spatial resolutions well below 100 ps and 100 microns, respectively, have been reported at event rates as high as 1 MHz, for up to 40 mm effective detection diameter. In this paper we will discuss several applications like wide-field fluorescence microscopy and dual γ/fast-neutron radiography for air cargo screening and conclude with an outlook on large-area detectors for thermal neutrons based on MCPs.

  18. Portable Heart Rate Detector Based on Photoplethysmography with Android Programmable Devices for Ubiquitous Health Monitoring System

    Directory of Open Access Journals (Sweden)

    Chi Kin Lao

    2013-01-01

    Full Text Available In this paper, a miniature portable heart rate detector system is implemented by modern hardware ICs and simple sensor circuit with software executable on both PC and Android platform. The biosignal is first extracted via photoplethysmography (PPG principle into electric signal. Then a microprocessor is used to covert biosignal from analog to digital format, suitably for feeding into an RF module (nRF24L01 for RF transmission. On the receiver end, the computer and/or smart phone can analyze the data using a robust algorithm that can detect peaks of the PPG waveform, hence to calculating the heart rate. Some application software running on Windows and Android phone have been developed to display heart rate information and time domain waveform to users for health care monitoring. In the future, pure Bluetooth technology will be used for wireless personal communications instead of RF modules. At the same time, the data can be sent to computer console using existing available networks (3G, 4G, WiFi, etc. for health database logging purpose.

  19. Determination of $\\alpha_{s}$ using Jet Rates at LEP with the OPAL detector

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, Robert M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hill, J.C.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krasznahorkay, A.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, Niels T.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rossi, A.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, Matthias; Schumacher, M.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2006-01-01

    Hadronic events produced in e+e- collisions by the LEP collider and recorded by the OPAL detector were used to form distributions based on the number of reconstructed jets. The data were collected between 1995 and 2000 and correspond to energies of 91 GeV, 130-136 GeV and 161-209 GeV. The jet rates were determined using four different jet-finding algorithms (Cone, JADE, Durham and Cambridge). The differential two-jet rate and the average jet rate with the Durham and Cambridge algorithms were used to measure alpha(s) in the LEP energy range by fitting an expression in which order alpah_2s calculations were matched to a NLLA prediction and fitted to the data. Combining the measurements at different centre-of-mass energies, the value of alpha_s (Mz) was determined to be alpha(s)(Mz)=0.1177+-0.0006(stat.)+-0.0012$(expt.)+-0.0010(had.)+-0.0032

  20. Complex pulsing schemes for high frame rate imaging

    DEFF Research Database (Denmark)

    Misaridis, Thanassis; Fink, Mathias; Jensen, Jørgen Arendt

    2002-01-01

    High frame rate ultrasound imaging can be achieved by simultaneous transmission of multiple focused beams along different directions. However, image quality degrades by the interference among beams. An alternative approach is to transmit spherical waves of a basic short pulse with frequency coding...... with linear frequency modulation along the transducer elements, that cover the 70% fractional bandwidth of the 7 MHz transducer. The resulted images (after beamforming and matched filtering) show an axial resolution at the same order as in conventional pulse excitation and axial sidelobes down to -45 d......B. With the proposed imaging strategy of pulse train excitation, a whole image can be formed with only two emissions, making it possible to obtain high quality images at a frame rate of 20 to 25 times higher than that of conventional phased array imaging...

  1. Studying {sup 222}Rn exhalation rate from soil and sand samples using CR-39 detector

    Energy Technology Data Exchange (ETDEWEB)

    Shafi-ur-Rehman [Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad (Pakistan); Matiullah [Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad (Pakistan)]. E-mail: matiullah@pieas.edu.pk; Shakeel-ur-Rehman [Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad (Pakistan); Rahman, Said [Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad (Pakistan)

    2006-07-15

    Accurate knowledge of exhalation rate plays an important role in characterization of the radon source strength in building materials and soil. It is a useful quantity to compare the relative importance of different materials and soil types. Majority of houses in Pakistan are mainly constructed from soil and sand. Therefore, studies concerning the determination of radon exhalation rate from these materials were carried out using CR-39 based NRPB radon dosimeters. In this context, samples were collected from different towns of the Bahawalpur Division, Punjab and major cities of NWFP. After treatment, samples were placed in plastic containers and dosimeters were installed in it at heights of 25cm above the surface of the samples. These containers were hermetically sealed and stored for three weeks to attain equilibrium between {sup 222}Rn and {sup 226}Ra. After exposure to radon, CR-39 detectors were etched in 25% NaOH at 80 deg. C for 16h. From the measured radon concentration values, {sup 222}Rn exhalation rates were determined. It ranged from 1.56 to 3.33Bqm{sup -2}h{sup -1} for the soil collected from the Bahawalpur Division and 2.49-4.66Bqm{sup -2}h{sup -1} for NWFP. The {sup 222}Rn exhalation rates from the sand samples were found to range from 2.78 to 20.8Bqm{sup -2}h{sup -1} for the Bahawalpur Division and from 0.99 to 4.2Bqm{sup -2}h{sup -1} for NWFP. {sup 226}Ra contents were also determined in the above samples which ranged from 28 to 36.5Bqkg{sup -1} in the soil samples collected from the Bahawalpur Division and from 40.9 to 51.9Bqkg{sup -1} in the samples collected from NWFP. In sand samples, {sup 226}Ra contents ranged from 49.2 to 215Bqkg{sup -1} and 22.6-27Bqkg{sup -1} in the samples collected from the Bahawalpur Division and NWFP, respectively. {sup 226}Ra contents in these samples were also determined using HPGe detector. The results of both the techniques are in good agreement within experimental errors.

  2. Photon-statistics-based classical ghost imaging with one single detector.

    Science.gov (United States)

    Kuhn, Simone; Hartmann, Sébastien; Elsäßer, Wolfgang

    2016-06-15

    We demonstrate a novel ghost imaging (GI) scheme based on one single-photon-counting detector with subsequent photon statistics analysis. The key idea is that instead of measuring correlations between the object and reference beams such as in standard GI schemes, the light of the two beams is superimposed. The photon statistics analysis of this mixed light allows us to determine the photon number distribution as well as to calculate the central second-order correlation coefficient. The image information is obtained as a function of the spatial resolution of the reference beam. The performance of this photon-statistics-based GI system with one single detector (PS-GI) is investigated in terms of visibility and resolution. Finally, the knowledge of the complete photon statistics allows easy access to higher correlation coefficients such that we are able to perform here third- and fourth-order GI. The PS-GI concept can be seen as a complement to already existing GI technologies thus enabling a broader dissemination of GI as a superior metrology technique, paving the road for new applications in particular with advanced photon counting detectors.

  3. Characterization of the imaging performance of the simultaneously counting and integrating X-ray detector CIX

    Energy Technology Data Exchange (ETDEWEB)

    Fink, Johannes

    2010-01-15

    The CIX detector is a direct converting hybrid pixel detector designed for medical X-ray imaging applications. Its de ning feature is the simultaneous operation of a photon counter as well as an integrator in every pixel cell. This novel approach o ers a dynamic range of more than five orders of magnitude, as well as the ability to directly obtain the average photon energy from the measured data. Several CIX 0.2 ASICs have been successfully connected to CdTe, CdZnTe and Si sensors. These detector modules were tested with respect to the imaging performance of the simultaneously counting and integrating concept under X-ray irradiation. Apart from a characterization of the intrinsic benefits of the CIX concept, the sensor performance was also investigated. Here, the two parallel signal processing concepts offer valuable insights into material related effects like polarization and temporal response. The impact of interpixel coupling effects like charge-sharing, Compton scattering and X-ray fluorescence was evaluated through simulations and measurements. (orig.)

  4. 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.

  5. Mercuric iodide room-temperature array detectors for gamma-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Patt, B. [Xsirius, Inc, Camarillo, CA (United States)

    1994-11-15

    Significant progress has been made recently in the development of mercuric iodide detector arrays for gamma-ray imaging, making real the possibility of constructing high-performance small, light-weight, portable gamma-ray imaging systems. New techniques have been applied in detector fabrication and then low noise electronics which have produced pixel arrays with high-energy resolution, high spatial resolution, high gamma stopping efficiency. Measurements of the energy resolution capability have been made on a 19-element protypical array. Pixel energy resolutions of 2.98% fwhm and 3.88% fwhm were obtained at 59 keV (241-Am) and 140-keV (99m-Tc), respectively. The pixel spectra for a 14-element section of the data is shown together with the composition of the overlapped individual pixel spectra. These techniques are now being applied to fabricate much larger arrays with thousands of pixels. Extension of these principles to imaging scenarios involving gamma-ray energies up to several hundred keV is also possible. This would enable imaging of the 208 keV and 375-414 keV 239-Pu and 240-Pu structures, as well as the 186 keV line of 235-U.

  6. Paediatric interventional cardiology: flat detector versus image intensifier using a test object.

    Science.gov (United States)

    Vano, E; Ubeda, C; Martinez, L C; Leyton, F; Miranda, P

    2010-12-07

    Entrance surface air kerma (ESAK) values and image quality parameters were measured and compared for two biplane angiography x-ray systems dedicated to paediatric interventional cardiology, one equipped with image intensifiers (II) and the other one with dynamic flat detectors (FDs). Polymethyl methacrylate phantoms of different thicknesses, ranging from 8 to 16 cm, and a Leeds TOR 18-FG test object were used. The parameters of the image quality evaluated were noise, signal-difference-to-noise ratio (SdNR), high contrast spatial resolution (HCSR) and three figures of merit combining entrance doses and signal-to-noise ratios or HCSR. The comparisons showed a better behaviour of the II-based system in the low contrast region over the whole interval of thicknesses. The FD-based system showed a better performance in HCSR. The FD system evaluated would need around two times more dose than the II system evaluated to reach a given value of SdNR; moreover, a better spatial resolution was measured (and perceived in conventional monitors) for the system equipped with flat detectors. According to the results of this paper, the use of dynamic FD systems does not lead to an automatic reduction in ESAK or to an automatic improvement in image quality by comparison with II systems. Any improvement also depends on the setting of the x-ray systems and it should still be possible to refine these settings for some of the dynamic FDs used in paediatric cardiology.

  7. Paediatric interventional cardiology: flat detector versus image intensifier using a test object

    Science.gov (United States)

    Vano, E.; Ubeda, C.; Martinez, L. C.; Leyton, F.; Miranda, P.

    2010-12-01

    Entrance surface air kerma (ESAK) values and image quality parameters were measured and compared for two biplane angiography x-ray systems dedicated to paediatric interventional cardiology, one equipped with image intensifiers (II) and the other one with dynamic flat detectors (FDs). Polymethyl methacrylate phantoms of different thicknesses, ranging from 8 to 16 cm, and a Leeds TOR 18-FG test object were used. The parameters of the image quality evaluated were noise, signal-difference-to-noise ratio (SdNR), high contrast spatial resolution (HCSR) and three figures of merit combining entrance doses and signal-to-noise ratios or HCSR. The comparisons showed a better behaviour of the II-based system in the low contrast region over the whole interval of thicknesses. The FD-based system showed a better performance in HCSR. The FD system evaluated would need around two times more dose than the II system evaluated to reach a given value of SdNR; moreover, a better spatial resolution was measured (and perceived in conventional monitors) for the system equipped with flat detectors. According to the results of this paper, the use of dynamic FD systems does not lead to an automatic reduction in ESAK or to an automatic improvement in image quality by comparison with II systems. Any improvement also depends on the setting of the x-ray systems and it should still be possible to refine these settings for some of the dynamic FDs used in paediatric cardiology.

  8. Paediatric interventional cardiology: flat detector versus image intensifier using a test object

    Energy Technology Data Exchange (ETDEWEB)

    Vano, E [Radiology Department, Medicine School, Complutense University and San Carlos University Hospital, 28040 Madrid (Spain); Ubeda, C [Clinical Sciences Department, Faculty of the Science of Health and CIHDE, Tarapaca University, 18 de Septiembre 2222, Arica (Chile); Martinez, L C [Medical Physics and Radiation Protection Service, 12 de Octubre University Hospital, Madrid (Spain); Leyton, F [Institute of Public Health of Chile, Marathon 1000, Nunoa, Santiago (Chile); Miranda, P, E-mail: eliseov@med.ucm.e [Hemodynamic Department, Cardiovascular Service, Luis Calvo Mackenna Hospital, Avenida Antonio Varaas 360, Providencia, Santiago (Chile)

    2010-12-07

    Entrance surface air kerma (ESAK) values and image quality parameters were measured and compared for two biplane angiography x-ray systems dedicated to paediatric interventional cardiology, one equipped with image intensifiers (II) and the other one with dynamic flat detectors (FDs). Polymethyl methacrylate phantoms of different thicknesses, ranging from 8 to 16 cm, and a Leeds TOR 18-FG test object were used. The parameters of the image quality evaluated were noise, signal-difference-to-noise ratio (SdNR), high contrast spatial resolution (HCSR) and three figures of merit combining entrance doses and signal-to-noise ratios or HCSR. The comparisons showed a better behaviour of the II-based system in the low contrast region over the whole interval of thicknesses. The FD-based system showed a better performance in HCSR. The FD system evaluated would need around two times more dose than the II system evaluated to reach a given value of SdNR; moreover, a better spatial resolution was measured (and perceived in conventional monitors) for the system equipped with flat detectors. According to the results of this paper, the use of dynamic FD systems does not lead to an automatic reduction in ESAK or to an automatic improvement in image quality by comparison with II systems. Any improvement also depends on the setting of the x-ray systems and it should still be possible to refine these settings for some of the dynamic FDs used in paediatric cardiology.

  9. Apparent exchange rate imaging in anisotropic systems

    DEFF Research Database (Denmark)

    Sønderby, Casper Kaae; Lundell, Henrik M; Søgaard, Lise V;

    2014-01-01

    Double-wave diffusion experiments offer the possibility of probing correlation between molecular diffusion at multiple time points. It has recently been shown that this technique is capable of measuring the exchange of water across cellular membranes. The aim of this study was to investigate the ...... the effect of macroscopic tissue anisotropy on the measurement of the apparent exchange rate (AXR) in multicompartment systems.......Double-wave diffusion experiments offer the possibility of probing correlation between molecular diffusion at multiple time points. It has recently been shown that this technique is capable of measuring the exchange of water across cellular membranes. The aim of this study was to investigate...

  10. Comparative study of two flat-panel x-ray detectors applied to small-animal imaging cone-beam micro-CT

    OpenAIRE

    2008-01-01

    Proceeding of: 2008 IEEE Nuclear Science Symposium Conference Record (NSS '08), Dresden, Germany, 19-25 Oct. 2008 This work compares two different X-ray flat-panel detectors for its use in high-speed, cone-beam CT applied to small-animal imaging. The main differences between these two devices are the scintillators and the achievable frame rate. Both devices have been tested in terms of system linearity, sensitivity, resolution, stability and noise properties, taking into account the dif...

  11. An investigation of the performance of a coaxial HPGe detector operating in a magnetic resonance imaging field

    Energy Technology Data Exchange (ETDEWEB)

    Harkness, L.J., E-mail: ljh@ns.ph.liv.ac.u [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Boston, A.J.; Boston, H.C.; Cole, P.; Cresswell, J.R.; Filmer, F.; Jones, M.; Judson, D.S.; Nolan, P.J.; Oxley, D.C.; Sampson, J.A.; Scraggs, D.P.; Slee, M.J. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Bimson, W.E.; Kemp, G.J. [MARIARC, University of Liverpool, Liverpool L69 3GE (United Kingdom); Groves, J.; Headspith, J.; Lazarus, I.; Simpson, J. [STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Cooper, R.J. [Joint Institute for Heavy Ion Research, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6371 (United States)

    2011-05-11

    Nuclear medical imaging modalities such as positron emission tomography and single photon emission computed tomography are used to probe physiological functions of the body by detecting gamma rays emitted from biologically targeted radiopharmaceuticals. A system which is capable of simultaneous data acquisition for nuclear medical imaging and magnetic resonance imaging is highly sought after by the medical imaging community. Such a device could provide a more complete medical insight into the functions of the body within a well-defined structural context. However, acquiring simultaneous nuclear/MRI sequences are technically challenging due to the conventional photomultiplier tube readout employed by most existing scintillator detector systems. A promising solution is a nuclear imaging device composed of semiconductor detectors that can be operated with a standard MRI scanner. However, the influence of placing a semiconductor detector such as high purity germanium (HPGe) within or close to the bore of an MRI scanner, where high magnetic fields are present, is not well understood. In this paper, the performance of a HPGe detector operating in a high strength static (B{sub S}) MRI field along with fast switching gradient fields and radiofrequency from the MRI system has been assessed. The influence of the B{sub S} field on the energy resolution of the detector has been investigated for various positions and orientations of the detector within the magnetic field. The results have then been interpreted in terms of the influence of the B{sub S} field on the charge collection properties. MRI images have been acquired with the detector situated at the entrance of the MRI bore to investigate the effects of simultaneous data acquisition on detector performance and MRI imaging.

  12. The Use of Radiation Detectors in Medicine: The Future of Molecular Imaging and Multimodality Imaging: Advantages and Technological Challenges (3/3)

    CERN Document Server

    CERN. Geneva

    2009-01-01

    The development of radiation detectors in the field of nuclear and particle physics has had a terrific impact in medical imaging since this latter discipline took off in late ’70 with the invention of the CT scanners. The massive use in High Energy Physics of position sensitive gas detectors, of high Z and high density scintillators coupled to Photomultiplier (PMT) and Position Sensitive Photomultipliers (PSPMT), and of solid state detectors has triggered during the last 30 years a series of novel applications in Medical Imaging with ionizing radiation. The accelerated scientific progression in genetics and molecular biology has finally generated what it is now called Molecular Imaging. This field of research presents additional challenges not only in the technology of radiation detector, but more and more in the ASIC electronics, fast digital readout and parallel software. In this series of three lectures I will try to present how high energy physics and medical imaging development have both benefited by t...

  13. A binary readout chip for silicon microstrip detector in proton imaging application

    Science.gov (United States)

    Sipala, V.; Bruzzi, M.; Bondì, M.; Bonanno, D.; Cadeddu, S.; Carpinelli, M.; Cirrone, G. A. P.; Civinini, C.; Cuttone, G.; Lai, A.; Leonora, E.; Lo Presti, D.; Maccioni, G.; Pallotta, S.; Randazzo, N.; Scaringella, M.; Talamonti, C.; Tesi, M.; Vanzi, E.

    2017-01-01

    The mixed-signal PRIMA-chip has been developed for sensitive-position silicon detector in proton imaging application. The chip is based upon the binary readout architecture which, providing fully parallel signal processing, is a good solution for high intensity radiation application. It includes 32-front-end channels with a charge preamplifier, a shaper and a comparator. In order to adjust the comparator thresholds, each channel contains a 8-bit DAC, programmed using an I2C like interface. The PRIMA-chip has been fabricated using the AMS 0.35 μm standard CMOS process and its performances have been tested coupling it to the detectors used in the tracker assembled for the pCT (proton Computed Tomography) apparatus.

  14. An investigation of performance characteristics of a pixellated room-temperature semiconductor detector for medical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, P; Santos, A [Centro de Investigacion Biomedica de Bioningenieria, Biomateriales y Nanomedicina, CEEI-Modulo 3, C/ Maria de Luna, 11, 50018 Zaragoza (United States); Darambara, D G, E-mail: pguerra@ciber-bbn.e [Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Fulham Road, London SW3 6JJ (United Kingdom)

    2009-09-07

    The operation of any semiconductor detector depends on the movement of the charge carriers, which are created within the material when radiation passes through, as a result of energy deposition. The carrier movement in the bulk semiconductor induces charges on the metal electrodes, and therefore a current on the electrodes and the external circuit. The induced charge strongly depends on the material transport parameters as well as the geometrical dimensions of a pixellated semiconductor detector. This work focuses on the performance optimization in terms of energy resolution, detection efficiency and intrinsic spatial resolution of a room-temperature semiconductor pixellated detector based on CdTe/CdZnTe. It analyses and inter-relates these performance figures for various dimensions of CdTe and CdZnTe detectors and for an energy range spanning from x-ray (25 keV) to PET (511 keV) imaging. Monte Carlo simulations, which integrate a detailed and accurate noise model, are carried out to investigate several CdTe/CdZnTe configurations and to determine possible design specifications. Under the considered conditions, the simulations demonstrate the superiority of the CdZnTe over the CdTe in terms of energy resolution and sensitivity in the photopeak. Further, according to the results, the spatial resolution is maximized at high energies and the energy resolution at low energies, while a reasonable detection efficiency is achieved at high energies, with a 1 x 1 x 6 mm{sup 3} CdZnTe pixellated detector.

  15. Quantum dot imaging in the second near-infrared optical window: studies on reflectance fluorescence imaging depths by effective fluence rate and multiple image acquisition.

    Science.gov (United States)

    Jung, Yebin; Jeong, Sanghwa; Nayoun, Won; Ahn, Boeun; Kwag, Jungheon; Geol Kim, Sang; Kim, Sungjee

    2015-04-01

    Quantum dot (QD) imaging capability was investigated by the imaging depth at a near-infrared second optical window (SOW; 1000 to 1400 nm) using time-modulated pulsed laser excitations to control the effective fluence rate. Various media, such as liquid phantoms, tissues, and in vivo small animals, were used and the imaging depths were compared with our predicted values. The QD imaging depth under excitation of continuous 20 mW/cm(2) laser was determined to be 10.3 mm for 2 wt%hemoglobin phantom medium and 5.85 mm for 1 wt% intralipid phantom, which were extended by more than two times on increasing the effective fluence rate to 2000 mW/cm(2). Bovine liver and porcine skin tissues also showed similar enhancement in the contrast-to-noise ratio (CNR) values. A QD sample was inserted into the abdomen of a mouse.With a higher effective fluence rate, the CNR increased more than twofold and the QD sample became clearly visualized, which was completely undetectable under continuous excitation.Multiple acquisitions of QD images and averaging process pixel by pixel were performed to overcome the thermal noise issue of the detector in SOW, which yielded significant enhancement in the imaging capability, showing up to a 1.5 times increase in the CNR.

  16. Detector system comparison using relative CNR for specific imaging tasks related to neuro-endovascular image-guided interventions (neuro-EIGIs)

    Science.gov (United States)

    Loughran, Brendan; Swetadri Vasan, S. N.; Singh, Vivek; Ionita, Ciprian N.; Jain, Amit; Bednarek, Daniel R.; Rudin, Stephen

    2014-03-01

    Neuro-EIGIs require visualization of very small endovascular devices and small vessels. A Microangiographic Fluoroscope (MAF) x-ray detector was developed to improve on the standard flat panel detector's (FPD's) ability to visualize small objects during neuro-EIGIs. To compare the performance of FPD and MAF imaging systems, specific imaging tasks related to those encountered during neuro-EIGIs were used to assess contrast to noise ratio (CNR) of different objects. A bar phantom and a stent were placed at a fixed distance from the x-ray focal spot to mimic a clinical imaging geometry and both objects were imaged by each detector system. Imaging was done without anti-scatter grids and using the same conditions for each system including: the same x-ray beam quality, collimator position, source to imager distance (SID), and source to object distance (SOD). For each object, relative contrasts were found for both imaging systems using the peak and trough signals. The relative noise was found using mean background signal and background noise for varying detector exposures. Next, the CNRs were found for these values for each object imaged and for each imaging system used. A relative CNR metric is defined and used to compare detector imaging performance. The MAF utilizes a temporal filter to reduce the overall image noise. The effects of using this filter with the MAF while imaging the clinical object's CNRs are reported. The relative CNR for the detectors demonstrated that the MAF has superior CNRs for most objects and exposures investigated for this specific imaging task.

  17. Balloon flight background measurement with actively-shielded planar and imaging CZT detectors

    Science.gov (United States)

    Bloser, Peter F.; Narita, Tomohiko; Jenkins, Jonathan A.; Perrin, Marshall; Murray, Ruth; Grindlay, Jonathan E.

    2002-01-01

    We present results from the flight of two prototype CZT detectors on a scientific balloon payload in September 2000. The first detector, referred to as CZT1, consisted of a 10 mm x 10 mm x 2 mm CZT crystal with a single gold planar electrode readout. This detector was shielded by a combination of a passive collimator in the front, giving a 40 degree field of view and surrounded by plastic scintillator, and a thick BGO crystal in the rear. The second detector, CZT2, comprised two 10 mm x 10 mm x 5 mm CZT crystals, one made of eV Products high pressure Bridgman material and the other of IMARAD horizontal Bridgman material, each fashioned with a 4 x 4 array of gold pixels on a 2.5 mm pitch. The pixellated detectors were flip-chip-mounted side by side and read out by a 32-channel ASIC. This detector was also shielded by a passive/plastic collimator in the front, but used only additional passive/plastic shielding in the rear. Both experiments were flown from Ft. Sumner, NM on September 19, 2000 on a 24 hour balloon flight. Both instruments performed well. CZT1 recorded a non-vetoed background level at 100 keV of approximately 1 x 10-3 cm-2s-1keV-1. Raising the BGO threshold from 50 keV to approximately 1 MeV produced only an 18% increase in this level. CZT2 recorded a background at 100 keV of approximately 4 times 10-3 cts cm-2s-1keV-1 in the eV Products detector and approximately 6 x 10-3 cts cm-2s-1keV-1 in the IMARAD detector, a difference possibly due to our internal background subtracting procedure. Both CZT1 and CZT2 spectra were in basic agreement with Monte Carlo simulations, though both recorded systematically higher count rates at high energy than predicted. No lines were observed, indicating that neutron capture reactions, at least those producing decay lines at a few 100 keV, are not significant components of the CZT background. Comparison of the CZT1 and CZT2 spectra indicates that passive/plastic shielding may provide adequately low background levels for

  18. Imaging of cochlear implant electrode array with flat-detector CT and conventional multislice CT: comparison of image quality and radiation dose.

    Science.gov (United States)

    Struffert, Tobias; Hertel, Victoria; Kyriakou, Yannis; Krause, Jens; Engelhorn, Tobias; Schick, Bernhard; Iro, Heinrich; Hornung, Joachim; Doerfler, Arnd

    2010-04-01

    Cochlear implantation assessment is possible using commercially available standard flat-detector computed tomography (FD-CT) protocols. Image quality is superior to multislice CT (MSCT). The radiation dose of FD-CT is lower in comparison with MSCT standard protocols and may therefore overcome the limitations of MSCT in the evaluation of cochlear implants. FD-CT offers higher spatial resolution than MSCT. Our objective was to compare the image quality of FD-CT to conventional MSCT in the visualization of a cochlear implant electrode array with respect to radiation exposure. An isolated temporal bone specimen was scanned using a commercially available FD-CT system and a 4 and 64 row MSCT scanner. Different scanning protocols were used. Image quality was assessed by four independent readers using a scoring system with different criteria describing delineation of the cochlea and the electrode array, image noise and spatial resolution. Radiation dose was measured using the CT dose index (CTDI) and a 16 cm acrylic phantom. Image quality was rated superior for FD-CT for all criteria by all readers. Single electrode contacts were only visible in FD-CT and assessment of implant position was improved by FD-CT. The radiation dose of FD-CT was half that of MSCT standard protocols.

  19. Measurements with a Ge detector and Monte Carlo computations of dose rate yields due to cosmic muons.

    Science.gov (United States)

    Clouvas, A; Xanthos, S; Antonopoulos-Domis, M; Silva, J

    2003-02-01

    The present work shows how portable Ge detectors can be useful for measurements of the dose rate due to ionizing cosmic radiation. The methodology proposed converts the cosmic radiation induced background in a Ge crystal (energy range above 3 MeV) to the absorbed dose rate due to muons, which are responsible for 75% of the cosmic radiation dose rate at sea level. The key point is to observe in the high energy range (above 20 MeV) the broad muon peak resulting from the most probable energy loss of muons in the Ge detector. An energy shift of the muon peak was observed, as expected, for increasing dimensions of three Ge crystals (10%, 20%, and 70% efficiency). Taking into account the dimensions of the three detectors the location of the three muon peaks was reproduced by Monte Carlo computations using the GEANT code. The absorbed dose rate due to muons has been measured in 50 indoor and outdoor locations at Thessaloniki, the second largest town of Greece, with a portable Ge detector and converted to the absorbed dose rate due to muons in an ICRU sphere representing the human body by using a factor derived from Monte Carlo computations. The outdoor and indoor mean muon dose rate was 25 nGy h(-1) and 17.8 nGy h(-1), respectively. The shielding factor for the 40 indoor measurements ranges from 0.5 to 0.9 with a most probable value between 0.7-0.8.

  20. 10μm pitch family of InSb and XBn detectors for MWIR imaging

    Science.gov (United States)

    Gershon, G.; Avnon, E.; Brumer, M.; Freiman, W.; Karni, Y.; Niderman, T.; Ofer, O.; Rosenstock, T.; Seref, D.; Shiloah, N.; Shkedy, L.; Tessler, R.; Shtrichman, I.

    2017-02-01

    There has been a growing demand over the past few years for infrared detectors with a smaller pixel dimension. On the one hand, this trend of pixel shrinkage enables the overall size of a given Focal Plan Array (FPA) to be reduced, allowing the production of more compact, lower power, and lower cost electro-optical (EO) systems. On the other hand, it enables a higher image resolution for a given FPA area, which is especially suitable in infrared systems with a large format that are used with a wide Field of View (FOV). In response to these market trends SCD has developed the Blackbird family of 10 μm pitch MWIR digital infrared detectors. The Blackbird family is based on three different Read- Out Integrated Circuit (ROIC) formats: 1920×1536, 1280×1024 and 640×512, which exploit advanced and mature 0.18 μm CMOS technology and exhibit high functionality with relatively low power consumption. Two types of 10 μm pixel sensing arrays are supported. The first is an InSb photodiode array based on SCD's mature planar implanted p-n junction technology, which covers the full MWIR band, and is designed to operate at 77K. The second type of sensing array covers the blue part of the MWIR band and uses the patented XBn-InAsSb barrier detector technology that provides electro-optical performance equivalent to planar InSb but at operating temperatures as high as 150 K. The XBn detector is therefore ideal for low Size, Weight and Power (SWaP) applications. Both sensing arrays, InSb and XBn, are Flip-chip bonded to the ROICs and assembled into custom designed Dewars that can withstand harsh environmental conditions while minimizing the detector heat load. A dedicated proximity electronics board provides power supplies and timing to the ROIC and enables communication and video output to the system. Together with a wide range of cryogenic coolers, a high flexibility of housing designs and various modes of operation, the Blackbird family of detectors presents solutions for EO

  1. Performance of a gaseous detector based energy dispersive X-ray fluorescence imaging system: Analysis of human teeth treated with dental amalgam

    Energy Technology Data Exchange (ETDEWEB)

    Silva, A.L.M. [I3N, Physics Dept, University of Aveiro, 3810-193 Aveiro (Portugal); Figueroa, R.; Jaramillo, A. [Physics Department, Universidad de La Frontera, Temuco (Chile); Carvalho, M.L. [Atomic Physics Centre, University of Lisbon, 1649-03 Lisboa (Portugal); Veloso, J.F.C.A., E-mail: joao.veloso@ua.pt [I3N, Physics Dept, University of Aveiro, 3810-193 Aveiro (Portugal)

    2013-08-01

    Energy dispersive X-ray fluorescence (EDXRF) imaging systems are of great interest in many applications of different areas, once they allow us to get images of the spatial elemental distribution in the samples. The detector system used in this study is based on a micro patterned gas detector, named Micro-Hole and Strip Plate. The full field of view system, with an active area of 28 × 28 mm{sup 2} presents some important features for EDXRF imaging applications, such as a position resolution below 125 μm, an intrinsic energy resolution of about 14% full width at half maximum for 5.9 keV X-rays, and a counting rate capability of 0.5 MHz. In this work, analysis of human teeth treated by dental amalgam was performed by using the EDXRF imaging system mentioned above. The goal of the analysis is to evaluate the system capabilities in the biomedical field by measuring the drift of the major constituents of a dental amalgam, Zn and Hg, throughout the tooth structures. The elemental distribution pattern of these elements obtained during the analysis suggests diffusion of these elements from the amalgam to teeth tissues. - Highlights: • Demonstration of an EDXRF imaging system based on a 2D-MHSP detector for biological analysis • Evaluation of the drift of the dental amalgam constituents, throughout the teeth • Observation of Hg diffusion, due to hydroxyapatite crystal defects that compose the teeth tissues.

  2. Developing imaging capabilities of multi-channel detectors comparable to traditional x-ray detector technology for industrial and security applications

    Science.gov (United States)

    Jimenez, Edward S.; Collins, Noelle M.; Holswade, Erica A.; Devonshire, Madison L.; Thompson, Kyle R.

    2016-10-01

    This work will investigate the imaging capabilities of the Multix multi-channel linear array detector and its potential suitability for big-data industrial and security applications versus that which is currently deployed. Multi-channel imaging data holds huge promise in not only finer resolution in materials classification, but also in materials identification and elevated data quality for various radiography and computed tomography applications. The potential pitfall is the signal quality contained within individual channels as well as the required exposure and acquisition time necessary to obtain images comparable to those of traditional configurations. This work will present results of these detector technologies as they pertain to a subset of materials of interest to the industrial and security communities; namely, water, copper, lead, polyethylene, and tin.

  3. Space situational awareness satellites and ground based radiation counting and imaging detector technology

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Frank, E-mail: frank.jansen@dlr.de [DLR Institute of Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany); Behrens, Joerg [DLR Institute of Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany); Pospisil, Stanislav [Czech Technical University, IEAP, 12800 Prague 2, Horska 3a/22 (Czech Republic); Kudela, Karel [Slovak Academy of Sciences, IEP, 04001 Kosice, Watsonova 47 (Slovakia)

    2011-05-15

    We review the current status from the scientific and technological point of view of solar energetic particles, solar and galactic cosmic ray measurements as well as high energy UV-, X- and gamma-ray imaging of the Sun. These particles and electromagnetic data are an important tool for space situational awareness (SSA) aspects like space weather storm predictions to avoid failures in space, air and ground based technological systems. Real time data acquisition, position and energy sensitive imaging are demanded by the international space weather forecast services. We present how newly developed, highly miniaturized radiation detectors can find application in space in view of future SSA related satellites as a novel space application due to their counting and imaging capabilities.

  4. Imaging characterization of a new gamma ray detector based on CRY019 scintillation crystal for PET and SPECT applications

    Science.gov (United States)

    Polito, C.; Pani, R.; Trigila, C.; Cinti, M. N.; Fabbri, A.; Frantellizzi, V.; De Vincentis, G.; Pellegrini, R.; Pani, R.

    2017-02-01

    In the last 40 years, in the field of Molecular Medicine imaging there has been a huge growth in the employment and in the improvement of detectors for PET and SPECT applications in order to reach accurate diagnosis of the diseases. The most important feature required to these detectors is an high quality of images that is usually obtained benefitting from the development of a wide number of new scintillation crystals with high imaging performances. In this contest, features like high detection efficiency, short decay time, great spectral match with photodetectors, absence of afterglow and low costs are surely attractive. However, there are other factors playing an important role in the realization of high quality images such as energy and spatial resolutions, position linearity and contrast resolution. With the aim to realize an high performace gamma ray detector for PET and SPECT applications, this work is focused on the evaluation of the imaging characteristics of a recently developed scintillation crystal, CRY019.

  5. Calibration model of a dual gain flat panel detector for 2D and 3D x-ray imaging.

    Science.gov (United States)

    Schmidgunst, C; Ritter, D; Lang, E

    2007-09-01

    The continuing research and further development in flat panel detector technology have led to its integration into more and more medical x-ray systems for two-dimensional (2D) and three-dimensional (3D) imaging, such as fixed or mobile C arms. Besides the obvious advantages of flat panel detectors, like the slim design and the resulting optimum accessibility to the patient, their success is primarily a product of the image quality that can be achieved. The benefits in the physical and performance-related features as opposed to conventional image intensifier systems, (e.g., distortion-free reproduction of imaging information or almost linear signal response over a large dynamic range) can be fully exploited, however, only if the raw detector images are correctly calibrated and postprocessed. Previous procedures for processing raw data contain idealizations that, in the real world, lead to artifacts or losses in image quality. Thus, for example, temperature dependencies or changes in beam geometry, as can occur with mobile C arm systems, have not been taken into account up to this time. Additionally, adverse characteristics such as image lag or aging effects have to be compensated to attain the best possible image quality. In this article a procedure is presented that takes into account the important dependencies of the individual pixel sensitivity of flat panel detectors used in 2D or 3D imaging and simultaneously minimizes the work required for an extensive recalibration. It is suitable for conventional detectors with only one gain mode as well as for the detectors specially developed for 3D imaging with dual gain read-out technology.

  6. TOPICAL REVIEW: Predictions for the rates of compact binary coalescences observable by ground-based gravitational-wave detectors

    Science.gov (United States)

    Abadie, J.; Abbott, B. P.; Abbott, R.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Ajith, P.; Allen, B.; Allen, G.; Amador Ceron, E.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; Antonucci, F.; Aoudia, S.; Arain, M. A.; Araya, M.; Aronsson, M.; Arun, K. G.; Aso, Y.; Aston, S.; Astone, P.; Atkinson, D. E.; Aufmuth, P.; Aulbert, C.; Babak, S.; Baker, P.; Ballardin, G.; Ballmer, S.; Barker, D.; Barnum, S.; Barone, F.; Barr, B.; Barriga, P.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Bastarrika, M.; Bauchrowitz, J.; Bauer, Th S.; Behnke, B.; Beker, M. G.; Belczynski, K.; Benacquista, M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bigotta, S.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birindelli, S.; Biswas, R.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Blom, M.; Blomberg, A.; Boccara, C.; Bock, O.; Bodiya, T. P.; Bondarescu, R.; Bondu, F.; Bonelli, L.; Bork, R.; Born, M.; Bose, S.; Bosi, L.; Boyle, M.; Braccini, S.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Breyer, J.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Budzyński, R.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burguet-Castell, J.; Burmeister, O.; Buskulic, D.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Calloni, E.; Camp, J. B.; Campagna, E.; Campsie, P.; Cannizzo, J.; Cannon, K. C.; Canuel, B.; Cao, J.; Capano, C.; Carbognani, F.; Caride, S.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chalermsongsak, T.; Chalkley, E.; Charlton, P.; Chassande Mottin, E.; Chelkowski, S.; Chen, Y.; Chincarini, A.; Christensen, N.; Chua, S. S. Y.; Chung, C. T. Y.; Clark, D.; Clark, J.; Clayton, J. H.; Cleva, F.; Coccia, E.; Colacino, C. N.; Colas, J.; Colla, A.; Colombini, M.; Conte, R.; Cook, D.; Corbitt, T. R.; Corda, C.; Cornish, N.; Corsi, A.; Costa, C. A.; Coulon, J. P.; Coward, D.; Coyne, D. C.; Creighton, J. D. E.; Creighton, T. D.; Cruise, A. M.; Culter, R. M.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dahl, K.; Danilishin, S. L.; Dannenberg, R.; D'Antonio, S.; Danzmann, K.; Dari, A.; Das, K.; Dattilo, V.; Daudert, B.; Davier, M.; Davies, G.; Davis, A.; Daw, E. J.; Day, R.; Dayanga, T.; De Rosa, R.; DeBra, D.; Degallaix, J.; del Prete, M.; Dergachev, V.; DeRosa, R.; DeSalvo, R.; Devanka, P.; Dhurandhar, S.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Emilio, M. Di Paolo; Di Virgilio, A.; Díaz, M.; Dietz, A.; Donovan, F.; Dooley, K. L.; Doomes, E. E.; Dorsher, S.; Douglas, E. S. D.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Dueck, J.; Dumas, J. C.; Eberle, T.; Edgar, M.; Edwards, M.; Effler, A.; Ehrens, P.; Engel, R.; Etzel, T.; Evans, M.; Evans, T.; Fafone, V.; Fairhurst, S.; Fan, Y.; Farr, B. F.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Ferrante, I.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Flaminio, R.; Flanigan, M.; Flasch, K.; Foley, S.; Forrest, C.; Forsi, E.; Fotopoulos, N.; Fournier, J. D.; Franc, J.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Friedrich, D.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gammaitoni, L.; Garofoli, J. A.; Garufi, F.; Gemme, G.; Genin, E.; Gennai, A.; Gholami, I.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Giazotto, A.; Gill, C.; Goetz, E.; Goggin, L. M.; González, G.; Gorodetsky, M. L.; Goßler, S.; Gouaty, R.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Greverie, C.; Grosso, R.; Grote, H.; Grunewald, S.; Guidi, G. M.; Gustafson, E. K.; Gustafson, R.; Hage, B.; Hall, P.; Hallam, J. M.; Hammer, D.; Hammond, G.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Haughian, K.; Hayama, K.; Heefner, J.; Heitmann, H.; Hello, P.; Heng, I. S.; Heptonstall, A.; Hewitson, M.; Hild, S.; Hirose, E.; Hoak, D.; Hodge, K. A.; Holt, K.; Hosken, D. J.; Hough, J.; Howell, E.; Hoyland, D.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Jaranowski, P.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kanner, J.; Katsavounidis, E.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kells, W.; Keppel, D. G.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, C.; Kim, H.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kondrashov, V.; Kopparapu, R.; Koranda, S.; Kowalska, I.; Kozak, D.; Krause, T.; Kringel, V.; Krishnamurthy, S.; Krishnan, B.; Królak, A.; Kuehn, G.; Kullman, J.; Kumar, R.; Kwee, P.; Landry, M.; Lang, M.; Lantz, B.; Lastzka, N.; Lazzarini, A.; Leaci, P.; Leong, J.; Leonor, I.; Leroy, N.; Letendre, N.; Li, J.; Li, T. G. F.; Lin, H.

    2010-09-01

    We present an up-to-date, comprehensive summary of the rates for all types of compact binary coalescence sources detectable by the initial and advanced versions of the ground-based gravitational-wave detectors LIGO and Virgo. Astrophysical estimates for compact-binary coalescence rates depend on a number of assumptions and unknown model parameters and are still uncertain. The most confident among these estimates are the rate predictions for coalescing binary neutron stars which are based on extrapolations from observed binary pulsars in our galaxy. These yield a likely coalescence rate of 100 Myr-1 per Milky Way Equivalent Galaxy (MWEG), although the rate could plausibly range from 1 Myr-1 MWEG-1 to 1000 Myr-1 MWEG-1 (Kalogera et al 2004 Astrophys. J. 601 L179; Kalogera et al 2004 Astrophys. J. 614 L137 (erratum)). We convert coalescence rates into detection rates based on data from the LIGO S5 and Virgo VSR2 science runs and projected sensitivities for our advanced detectors. Using the detector sensitivities derived from these data, we find a likely detection rate of 0.02 per year for Initial LIGO-Virgo interferometers, with a plausible range between 2 × 10-4 and 0.2 per year. The likely binary neutron-star detection rate for the Advanced LIGO-Virgo network increases to 40 events per year, with a range between 0.4 and 400 per year.

  7. Space-time encoding for high frame rate ultrasound imaging

    DEFF Research Database (Denmark)

    Misaridis, Thanssis; Jensen, Jørgen Arendt

    2002-01-01

    Frame rate in ultrasound imaging can be dramatically increased by using sparse synthetic transmit aperture (STA) beamforming techniques. The two main drawbacks of the method are the low signal-to-noise ratio (SNR) and the motion artifacts, that degrade the image quality. In this paper we propose ...

  8. Performance of a large size triple GEM detector at high particle rate for the CBM Experiment at FAIR

    Science.gov (United States)

    Adak, Rama Prasad; Kumar, Ajit; Dubey, Anand Kumar; Chattopadhyay, Subhasis; Das, Supriya; Raha, Sibaji; Samanta, Subhasis; Saini, Jogender

    2017-02-01

    In CBM Experiment at FAIR, dimuons will be detected by a Muon Chamber (MUCH) consisting of segmented absorbers of varying widths and tracking chambers sandwiched between the absorber-pairs. In this fixed target heavy-ion collision experiment, operating at highest interaction rate of 10 MHz for Au+Au collision, the inner region of the 1st detector will face a particle rate of 1 MHz/cm2. To operate at such a high particle density, GEM technology based detectors have been selected for the first two stations of MUCH. We have reported earlier the performance of several small-size GEM detector prototypes built at VECC for use in MUCH. In this work, we report on a large GEM prototype tested with proton beam of momentum 2.36 GeV/c at COSY-Jülich Germany. The detector was read out using nXYTER operated in self-triggering mode. An efficiency higher than 96% at ΔVGEM = 375.2 V was achieved. The variation of efficiency with the rate of incoming protons has been found to vary within 2% when tested up to a maximum rate of 2.8 MHz/cm2. The gain was found to be stable at high particle rate with a maximum variation of ∼9%.

  9. An investigation of the Eigenvalue Calibration Method (ECM) using GASP for non-imaging and imaging detectors

    Science.gov (United States)

    Kyne, Gillian; Lara, David; Hallinan, Gregg; Redfern, Michael; Shearer, Andrew

    2016-02-01

    Polarised light from astronomical targets can yield a wealth of information about their source radiation mechanisms, and about the geometry of the scattered light regions. Optical observations, of both the linear and circular polarisation components, have been impeded due to non-optimised instrumentation. The need for suitable observing conditions and the availability of luminous targets are also limiting factors. The science motivation of any instrument adds constraints to its operation such as high signal-to-noise (SNR) and detector readout speeds. These factors in particular lead to a wide range of sources that have yet to be observed. The Galway Astronomical Stokes Polarimeter (GASP) has been specifically designed to make observations of these sources. GASP uses division of amplitude polarimeter (DOAP) (Compain and Drevillon Appl. Opt. 37, 5938-5944, 1998) to measure the four components of the Stokes vector (I, Q, U and V) simultaneously, which eliminates the constraints placed upon the need for moving parts during observation, and offers a real-time complete measurement of polarisation. Results from the GASP calibration are presented in this work for both a 1D detector system, and a pixel-by-pixel analysis on a 2D detector system. Following Compain et al. (Appl. Opt. 38, 3490-3502 1999) we use the Eigenvalue Calibration Method (ECM) to measure the polarimetric limitations of the instrument for each of the two systems. Consequently, the ECM is able to compensate for systematic errors introduced by the calibration optics, and it also accounts for all optical elements of the polarimeter in the output. Initial laboratory results of the ECM are presented, using APD detectors, where errors of 0.2 % and 0.1° were measured for the degree of linear polarisation (DOLP) and polarisation angle (PA) respectively. Channel-to-channel image registration is an important aspect of 2-D polarimetry. We present our calibration results of the measured Mueller matrix of each sample

  10. Multi-detector computed tomography imaging of large airway pathology:A pictorial review

    Institute of Scientific and Technical Information of China (English)

    Tejeshwar Singh Jugpal; Anju Garg; Gulshan Rai Sethi; Mradul Kumar Daga; Jyoti Kumar

    2015-01-01

    The tracheobronchial tree is a musculo-cartilagenous framework which acts as a conduit to aerate the lungs and consequently the entire body. A large spectrum of pathological conditions can involve the trachea and bronchial airways. These may be congenital anomalies, infections, post-intubation airway injuries, foreign body aspiration or neoplasms involving the airway. Appropriate management of airway disease requires an early and accurate diagnosis. In this pictorial essay review, we will comprehensively describe the various airway pathologies and their imaging findings by multi-detector computed tomography.

  11. Imaging the LHC beams with silicon and scintillating fibre vertex detectors

    Science.gov (United States)

    Rihl, M.

    2017-02-01

    The LHCb Vertex Locator (VELO) is used to reconstruct beam-gas interaction vertices which allows one to obtain precise profiles of the LHC beams. In LHCb, this information is combined with the profile of the reconstructed beam-beam collisions and with the LHC beam currents to perform precise measurements of the luminosity. This beam-gas imaging (BGI) method also allows one to study the transverse beam shapes, beam positions and angles in real time. Therefore, a demonstrator beam-gas vertex detector (BGV) based on scintillating fibre modules has been built and installed in LHC Ring 2 at point 4.

  12. Imaging the LHC beams with silicon and scintillating fibre vertex detectors

    CERN Document Server

    Rihl, M

    2016-01-01

    The LHCb Vertex Locator (VELO) is used to reconstruct beam–gas interaction vertices which allows one to obtain precise profiles of the LHC beams. In LHCb, this information is combined with the profile of the reconstructed beam–beam collisions and with the LHC beam currents to perform precise measurements of the luminosity. This beam–gas imaging (BGI) method also allows one to study the transverse beam shapes, beam positions and angles in real time. Therefore, a demonstrator beam–gas vertex detector (BGV) based on scintillating fibre modules has been built and installed in LHC Ring 2 at point 4.

  13. Construction of a Gas Electron Multiplier (GEM) Detector for Medical Imaging

    OpenAIRE

    2013-01-01

    A prototype Gas Electron Multiplier (GEM) detector is under construction for medical imaging purposes. A single thick GEM of size 10x10 cm^2 is assembled inside a square shaped air-tight box which is made of Perspex glass. In order to ionize gas inside the drift field two types of voltage supplier circuits were fabricated, and array of 2x4 pads of each size 4x8 mm^2 were utilized for collecting avalanche charges. Preliminary testing results show that the circuit which produces high voltage an...

  14. Monitor and control systems for the SLD Cherenkov Ring Imaging Detector

    Energy Technology Data Exchange (ETDEWEB)

    Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dunwoodie, W.; Fernandez, F.; Hallewell, G.; Kawahara, H.; Korff, P.; Kwon, Y.; Leith, D.; Muller, D.; Nagamine, T.; Pavel, T.; Rabinowitz, L.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Toge, N.; Va' Vra, J.; Williams, S.; Whitaker, J.; Wilson, R.J.; Bean, A.; Caldwell, D.; Duboscq, J.; Huber, J.; Lu, A.; McHugh, S.; Mathys, L.; Morriso

    1989-10-01

    To help ensure the stable long-term operation of a Cherenkov Ring Detector at high efficiency, a comprehensive monitor and control system is being developed. This system will continuously monitor and maintain the correct operating temperatures, and will provide an on-line monitor and maintain the correct operating temperatures, and will provide an on-line monitor of the pressures, flows, mixing, and purity of the various fluids. In addition the velocities and trajectories of Cherenkov photoelectrons drifting within the imaging chambers will be measured using a pulsed uv lamp and a fiberoptic light injection system. 9 refs., 6 figs.

  15. An X-ray imaging device based on a GEM detector with delay-line readout

    Science.gov (United States)

    Zhou, Yi; Li, Cheng; Sun, Yong-Jie; Shao, Ming

    2010-01-01

    An X-ray imaging device based on a triple-GEM (Gas Electron Multiplier) detector, a fast delay-line circuit with 700 MHz cut-off frequency and two dimensional readout strips with 150 μm width on the top and 250 μm width on the bottom, is designed and tested. The localization information is derived from the propagation time of the induced signals on the readout strips. This device has a good spatial resolution of 150 μm and works stably at an intensity of 105 Hz/mm2 with 8 keV X-rays.

  16. Imaging the LHC beams with silicon and scintillating fibre vertex detectors

    CERN Document Server

    Rihl, M

    2016-01-01

    The LHCb Vertex Locator (VELO) is used to reconstruct beam–gas interaction vertices which allows one to obtain precise profiles of the LHC beams. In LHCb, this information is combined with the profile of the reconstructed beam–beam collisions and with the LHC beam currents to perform precise measurements of the luminosity. This beam–gas imaging (BGI) method also allows one to study the transverse beam shapes, beam positions and angles in real time. Therefore, a demonstrator beam–gas vertex detector (BGV) based on scintillating fibre modules has been built and installed in LHC Ring 2 at point 4.

  17. Dark-field image contrast in transmission scanning electron microscopy: Effects of substrate thickness and detector collection angle.

    Science.gov (United States)

    Woehl, Taylor; Keller, Robert

    2016-12-01

    An annular dark field (ADF) detector was placed beneath a specimen in a field emission scanning electron microscope operated at 30kV to calibrate detector response to incident beam current, and to create transmission images of gold nanoparticles on silicon nitride (SiN) substrates of various thicknesses. Based on the linear response of the ADF detector diodes to beam current, we developed a method that allowed for direct determination of the percentage of that beam current forward scattered to the ADF detector from the sample, i.e. the transmitted electron (TE) yield. Collection angles for the ADF detector region were defined using a masking aperture above the detector and were systematically varied by changing the sample to detector distance. We found the contrast of the nanoparticles, relative to the SiN substrate, decreased monotonically with decreasing inner exclusion angle and increasing substrate thickness. We also performed Monte Carlo electron scattering simulations, which showed quantitative agreement with experimental contrast associated with the nanoparticles. Together, the experiments and Monte Carlo simulations revealed that the decrease in contrast with decreasing inner exclusion angle was due to a rapid increase in the TE yield of the low atomic number substrate. Nanoparticles imaged at low inner exclusion angles (50nm) showed low image contrast in their centers surrounded by a bright high-contrast halo on their edges. This complex image contrast was predicted by Monte Carlo simulations, which we interpreted in terms of mixing of the nominally bright field (BF) and ADF electron signals. Our systematic investigation of inner exclusion angle and substrate thickness effects on ADF t-SEM imaging provides fundamental understanding of the contrast mechanisms for image formation, which in turn suggest practical limitations and optimal imaging conditions for different substrate thicknesses.

  18. Using image simulation to test the effect of detector type on breast cancer detection

    Science.gov (United States)

    Mackenzie, Alistair; Warren, Lucy M.; Dance, David R.; Chakraborty, Dev P.; Cooke, Julie; Halling-Brown, Mark D.; Looney, Padraig T.; Wallis, Matthew G.; Given-Wilson, Rosalind M.; Alexander, Gavin G.; Young, Kenneth C.

    2014-03-01

    Introduction: The effect that the image quality associated with different image receptors has on cancer detection in mammography was measured using a novel method for changing the appearance of images. Method: A set of 270 mammography cases (one view, both breasts) was acquired using five Hologic Selenia and two Hologic Dimensions X-ray sets: 160 normal cases, 80 cases with subtle real non-calcification malignant lesions and 30 cases with biopsy proven benign lesions. Simulated calcification clusters were inserted into half of the normal cases. The 270 cases (Arm 1) were converted to appear as if they had been acquired on three other imaging systems: caesium iodide detector (Arm 2), needle image plate computed radiography (CR) (Arm 3) and powder phosphor CR (Arm 4). Five experienced mammography readers marked the location of suspected cancers in the images and classified the degree of visibility of the lesions. Statistical analysis was performed using JAFROC. Results: The differences in the visibility of calcification clusters between all pairs of arms were statistically significant (ptype had a significant impact on the visibility of all types of subtle cancers, with the largest impact being on the visibility of calcification clusters.

  19. Imaging the pericardium: appearances on ECG-gated 64-detector row cardiac computed tomography

    Science.gov (United States)

    O'Leary, S M; Williams, P L; Williams, M P; Edwards, A J; Roobottom, C A; Morgan-Hughes, G J; Manghat, N E

    2010-01-01

    Multidetector row computed tomography (MDCT) with its high spatial and temporal resolution has now become an established and complementary method for cardiac imaging. It can now be used reliably to exclude significant coronary artery disease and delineate complex coronary artery anomalies, and has become a valuable problem-solving tool. Our experience with MDCT imaging suggests that it is clinically useful for imaging the pericardium. It is important to be aware of the normal anatomy of the pericardium and not mistake normal variations for pathology. The pericardial recesses are visible in up to 44% of non-electrocardiogram (ECG)-gated MDCT images. Abnormalities of the pericardium can now be identified with increasing certainty on 64-detector row CT; they may be the key to diagnosis and therefore must not be overlooked. This educational review of the pericardium will cover different imaging techniques, with a significant emphasis on MDCT. We have a large research and clinical experience of ECG-gated cardiac CT and will demonstrate examples of pericardial recesses, their variations and a wide variety of pericardial abnormalities and systemic conditions affecting the pericardium. We give a brief relevant background of the conditions and reinforce the key imaging features. We aim to provide a pictorial demonstration of the wide variety of abnormalities of the pericardium and the pitfalls in the diagnosis of pericardial disease. PMID:20197434

  20. Simulation study comparing high-purity germanium and cadmium zinc telluride detectors for breast imaging

    Science.gov (United States)

    Campbell, D. L.; Peterson, T. E.

    2014-11-01

    We conducted simulations to compare the potential imaging performance for breast cancer detection with High-Purity Germanium (HPGe) and Cadmium Zinc Telluride (CZT) systems with 1% and 3.8% energy resolution at 140 keV, respectively. Using the Monte Carlo N-Particle (MCNP5) simulation package, we modelled both 5 mm-thick CZT and 10 mm-thick HPGe detectors with the same parallel-hole collimator for the imaging of a breast/torso phantom. Simulated energy spectra were generated, and planar images were created for various energy windows around the 140 keV photopeak. Relative sensitivity and scatter and the torso fractions were calculated along with tumour contrast and signal-to-noise ratios (SNR). Simulations showed that utilizing a ±1.25% energy window with an HPGe system better suppressed torso background and small-angle scattered photons than a comparable CZT system using a -5%/+10% energy window. Both systems provided statistically similar contrast and SNR, with HPGe providing higher relative sensitivity. Lowering the counts of HPGe images to match CZT count density still yielded equivalent contrast between HPGe and CZT. Thus, an HPGe system may provide equivalent breast imaging capability at lower injected radioactivity levels when acquiring for equal imaging time.

  1. Predictions for the Rates of Compact Binary Coalescences Observable by Ground-based Gravitational-wave Detectors

    CERN Document Server

    Abadie, J; Abbott, R; Abernathy, M; Accadia, T; Acernese, F; Adams, C; Adhikari, R; Ajith, P; Allen, B; Allen, G; Allwine, E; Ceron, E Amador; Amin, R S; Anderson, S B; Anderson, W G; Antonucci, F; Aoudia, S; Arain, M A; Araya, M; Arun, K G; Aso, Y; Aston, S; Astone, P; Atkinson, D E; Aufmuth, P; Aulbert, C; Babak, S; Baker, P; Ballardin, G; Ballmer, S; Barker, D; Barnum, S; Barone, F; Barr, B; Barriga, P; Barsotti, L; Barsuglia, M; Bartlett, J; Barton, M A; Bartos, I; Bassiri, R; Bastarrika, M; Bauchrowitz, J; Bauer, Th S; Behnke, B; Beker, M G; Belczynski, K; Benacquista, M; Bertolini, A; Betzwieser, J; Beveridge, N; Beyersdorf, P T; Bigotta, S; Bilenko, I A; Billingsley, G; Birch, J; Birindelli, S; Biswas, R; Bitossi, M; Bizouard, M A; Black, E; Blackburn, J K; Blackburn, L; Blair, D; Bland, B; Blom, M; Blomberg, A; Boccara, C; Bock, O; Bodiya, T P; Bondarescu, R; Bondu, F; Bonelli, L; Bork, R; Born, M; Bose, S; Bosi, L; Boyle, M; Braccini, S; Bradaschia, C; Brady, P R; Braginsky, V B; Brau, J E; Breyer, J; Bridges, D O; Brillet, A; Brinkmann, M; Brisson, V; Britzger, M; Brooks, A F; Brown, D A; Buckleitner, D; Budzyński, R; Bulik, T; Bulten, H J; Buonanno, A; Burguet--Castell, J; Burmeister, O; Buskulic, D; Byer, R L; Cadonati, L; Cagnoli, G; Calloni, E; Camp, J B; Campagna, E; Campsie, P; Cannizzo, J; Cannon, K C; Canuel, B; Cao, J; Capano, C; Carbognani, F; Caride, S; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Cella, G; Cepeda, C; Cesarini, E; Chalermsongsak, T; Chalkley, E; Charlton, P; Chassande-Mottin, E; Chatterji, S; Chelkowski, S; Chen, Y; Chincarini, A; Christensen, N; Chua, S S Y; Chung, C T Y; Clark, D; Clark, J; Clayton, J H; Cleva, F; Coccia, E; Colacino, C N; Colas, J; Colla, A; Colombini, M; Conte, R; Cook, D; Corbitt, T R C; Corda, C; Cornish, N; Corsi, A; Costa, C A; Coulon, J -P; Coward, D; Coyne, D C; Creighton, J D E; Creighton, T D; Cruise, A M; Culter, R M; Cumming, A; Cunningham, L; Cuoco, E; Dahl, K; Danilishin, S L; D'Antonio, S; Danzmann, K; Dari, A; Das, K; Dattilo, V; Daudert, B; Davier, M; Davies, G; Davis, A; Daw, E J; Day, R; Dayanga, T; De Rosa, R; DeBra, D; Degallaix, J; del Prete, M; Dergachev, V; DeRosa, R; DeSalvo, R; Devanka, P; Dhurandhar, S; Di Cintio, A; Di Fiore, L; Di Lieto, A; Emilio, M Di Paolo; Di Virgilio, A; Díaz, M; Dietz, A; Donovan, F; Dooley, K L; Doomes, E E; Douglas, E S D; Drago, M; Drever, R W P; Driggers, J C; Dueck, J; Dumas, J -C; Eberle, T; Edgar, M; Edwards, M; Effler, A; Ehrens, P; Espinoza, E; Etzel, T; Evans, M; Evans, T; Fafone, V; Fairhurst, S; Faltas, Y; Fan, Y; Farr, B F; Fazi, D; Fehrmann, H; Ferrante, I; Fidecaro, F; Finn, L S; Fiori, I; Flaminio, R; Flanigan, M; Flasch, K; Foley, S; Forrest, C; Forsi, E; Fotopoulos, N; Fournier, J -D; Franc, J; Frasca, S; Frasconi, F; Frede, M; Frei, M; Frei, Z; Freise, A; Frey, R; Fricke, T T; Friedrich, D; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Gammaitoni, L; Garofoli, J A; Garufi, F; Gemme, G; Genin, E; Gennai, A; Gholami, I; Ghosh, S; Giaime, J A; Giampanis, S; Giardina, K D; Giazotto, A; Gill, C; Goetz, E A; Goggin, L M; González, G; Gorodetsky, M L; Goßler, S; Gouaty, R; Graef, C; Granata, M; Grant, A; Gras, S; Gray, C; Greenhalgh, R J S; Gretarsson, A M; Greverie, C; Grosso, R; Grote, H; Grunewald, S; Guidi, G M; Gustafson, E K; Gustafson, R; Hage, B; Hall, P; Hallam, J M; Hammer, D; Hammond, G; Hanks, J; Hanna, C; Hanson, J; Harms, J; Harry, G M; Harry, I W; Harstad, E D; Haughian, K; Hayama, K; Heefner, J; Heitmann, H; Hello, P; Heng, I S; Heptonstall, A; Hewitson, M; Hild, S; Hirose, E; Hoak, D; Hodge, K A; Holt, K; Hosken, D J; Hough, J; Howell, E; Hoyland, D; Huet, D; Hughey, B; Husa, S; Huttner, S H; Huynh--Dinh, T; Ingram, D R; Inta, R; Isogai, T; Ivanov, A; Jackson, B; Jaranowski, P; Johnson, W W; Jones, D I; Jones, G; Jones, R; Ju, L; Kalmus, P; Kalogera, V; Kandhasamy, S; Kanner, J; Katsavounidis, E; Kawabe, K; Kawamura, S; Kawazoe, F; Kells, W; Keppel, D G; Khalaidovski, A; Khalili, F Y; Khazanov, E A; 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van Veggel, A A; Vass, S; Vaulin, R; Vavoulidis, M; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Veltkamp, C; Verkindt, D; Vetrano, F; Viceré, A; Villar, A; Vinet, J -Y; Vocca, H; Vorvick, C; Vyachanin, S P; Waldman, S J; Wallace, L; Wanner, A; Ward, R L; Was, M; Wei, P; Weinert, M; Weinstein, A J; Weiss, R; Wen, L; Wen, S; Wessels, P; West, M; Westphal, T; Wette, K; Whelan, J T; Whitcomb, S E; White, D; Whiting, B F; Wilkinson, C; Willems, P A; Williams, L; Willke, B; Winkelmann, L; Winkler, W; Wipf, C C; Wiseman, A G; Woan, G; Wooley, R; Worden, J; Yakushin, I; Yamamoto, H; Yamamoto, K; Yeaton-Massey, D; Yoshida, S; Yu, P; Yvert, M; Zanolin, M; Zhang, L; Zhang, Z; Zhao, C; Zimmermann, P J Z; Zotov, N; Zucker, M E; Zweizig, J

    2010-01-01

    We present an up-to-date, comprehensive summary of the rates for all types of compact binary coalescence sources detectable by the Initial and Advanced versions of the ground-based gravitational-wave detectors LIGO and Virgo. Astrophysical estimates for compact-binary coalescence rates depend on a number of assumptions and unknown model parameters, and are still uncertain. The most confident among these estimates are the rate predictions for coalescing binary neutron stars which are based on extrapolations from observed binary pulsars in our Galaxy. These yield a likely coalescence rate of 100 per Myr per Milky Way Equivalent Galaxy (MWEG), although the rate could plausibly range from 1 per Myr per MWEG to 1000 per Myr per MWEG. We convert coalescence rates into detection rates based on data from the LIGO S5 and Virgo VSR2 science runs and projected sensitivities for our Advanced detectors. Using the detector sensitivities derived from these data, we find a likely detection rate of 0.02 per year for Initial L...

  2. Highly multiplexible thermal kinetic inductance detectors for x-ray imaging spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ulbricht, Gerhard, E-mail: ulbricht@physics.ucsb.edu; Mazin, Benjamin A.; Szypryt, Paul; Walter, Alex B.; Bockstiegel, Clint [Department of Physics, University of California, Santa Barbara, California 93106 (United States); Bumble, Bruce [NASA Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, California 91125 (United States)

    2015-06-22

    For X-ray imaging spectroscopy, high spatial resolution over a large field of view is often as important as high energy resolution, but current X-ray detectors do not provide both in the same device. Thermal Kinetic Inductance Detectors (TKIDs) are being developed as they offer a feasible way to combine the energy resolution of transition edge sensors with pixel counts approaching CCDs and thus promise significant improvements for many X-ray spectroscopy applications. TKIDs are a variation of Microwave Kinetic Inductance Detectors (MKIDs) and share their multiplexibility: working MKID arrays with 2024 pixels have recently been demonstrated and much bigger arrays are under development. In this work, we present a TKID prototype, which is able to achieve an energy resolution of 75 eV at 5.9 keV, even though its general design still has to be optimized. We further describe TKID fabrication, characterization, multiplexing, and working principle and demonstrate the necessity of a data fitting algorithm in order to extract photon energies. With further design optimizations, we expect to be able to improve our TKID energy resolution to less than 10 eV at 5.9 keV.

  3. Neutron imaging detector based on the {mu}PIC micro-pixel chamber

    Energy Technology Data Exchange (ETDEWEB)

    Parker, J.D., E-mail: jparker@cr.scphys.kyoto-u.ac.jp [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Hattori, K.; Fujioka, H. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Harada, M. [Materials and Life Science Facility Division, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Iwaki, S.; Kabuki, S.; Kishimoto, Y.; Kubo, H.; Kurosawa, S.; Miuchi, K.; Nagae, T.; Nishimura, H. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Oku, T. [Materials and Life Science Facility Division, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Sawano, T. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Shinohara, T.; Suzuki, J. [Materials and Life Science Facility Division, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Takada, A.; Tanimori, T.; Ueno, K. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan)

    2013-01-01

    We have developed a prototype time-resolved neutron imaging detector employing the micro-pixel chamber ({mu}PIC), a micro-pattern gaseous detector, coupled with a field programmable gate array-based data acquisition system for applications in neutron radiography at high-intensity neutron sources. The prototype system, with an active area of 10 Multiplication-Sign 10 cm{sup 2} and operated at a gas pressure of 2 atm, measures both the energy deposition (via time-over-threshold) and three-dimensional track of each neutron-induced event, allowing the reconstruction of the neutron interaction point with improved accuracy. Using a simple position reconstruction algorithm, a spatial resolution of 349{+-}36{mu}m was achieved, with further improvement expected. The detailed tracking allows strong rejection of background gamma-rays, resulting in an effective gamma sensitivity of 10{sup -12} or less, coupled with stable, robust neutron identification. The detector also features a time resolution of 0.6{mu}s.

  4. Highly Multiplexible Thermal Kinetic Inductance Detectors for X-Ray Imaging Spectroscopy

    CERN Document Server

    Ulbricht, Gerhard; Szypryt, Paul; Walter, Alex B; Bockstiegel, Clint; Bumble, Bruce

    2015-01-01

    For X-ray imaging spectroscopy, high spatial resolution over a large field of view is often as important as high energy resolution, but current X-ray detectors do not provide both in the same device. Thermal Kinetic Inductance Detectors (TKIDs) are being developed as they offer a feasible way to combine the energy resolution of transition edge sensors with pixel counts approaching CCDs and thus promise significant improvements for many X-ray spectroscopy applications. TKIDs are a variation of Microwave Kinetic Inductance Detectors (MKIDs) and share their multiplexibility: working MKID arrays with 2024 pixels have recently been demonstrated and much bigger arrays are under development. In this work, we present our first working TKID prototypes which are able to achieve an energy