WorldWideScience

Sample records for dual detector cameras

  1. Neutron television camera detector

    International Nuclear Information System (INIS)

    Arndt, U.W.; Gilmore, D.J.

    1976-01-01

    A neutron area detector system is being developed at the Institut Laue-Langevin which is based on a system for x-rays. The system has a large counting rate capability; this is extremely important where the total background count exceeds the total counts in the signals of interest. Its spatial resolution is of the order of one mm, while the screen size is 400 mm. The main limitation of the system is its limited counting efficiency, and this is directly attributable to the optical self-absorption of the neutron phosphor. All coherent noise in the system, i.e., all noise synchronized with the TV scans, has to be kept lower than the first bit threshold. However, this requirement can be relaxed when dealing with diffraction patterns, such as those from single crystals, for which a local background is subtracted from the pattern

  2. Dual cameras acquisition and display system of retina-like sensor camera and rectangular sensor camera

    Science.gov (United States)

    Cao, Nan; Cao, Fengmei; Lin, Yabin; Bai, Tingzhu; Song, Shengyu

    2015-04-01

    For a new kind of retina-like senor camera and a traditional rectangular sensor camera, dual cameras acquisition and display system need to be built. We introduce the principle and the development of retina-like senor. Image coordinates transformation and interpolation based on sub-pixel interpolation need to be realized for our retina-like sensor's special pixels distribution. The hardware platform is composed of retina-like senor camera, rectangular sensor camera, image grabber and PC. Combined the MIL and OpenCV library, the software program is composed in VC++ on VS 2010. Experience results show that the system can realizes two cameras' acquisition and display.

  3. Dual-band infrared camera

    Science.gov (United States)

    Vogel, H.; Schlemmer, H.

    2005-10-01

    Every year, numerous accidents happen on European roads due to bad visibility (fog, night, heavy rain). Similarly, the dramatic aviation accidents of year 2001 in Milan and Zurich have reminded us that aviation safety is equally affected by reduced visibility. A dual-band thermal imager was developed in order to raise human situation awareness under conditions of reduced visibility especially in the automotive and aeronautical context but also for all transportation or surveillance tasks. The chosen wavelength bands are the Short Wave Infrared SWIR and the Long Wave Infrared LWIR band which are less obscured by reduced visibility conditions than the visible band. Furthermore, our field tests clearly show that the two different spectral bands very often contain complementary information. Pyramidal fusion is used to integrate complementary and redundant features of the multi-spectral images into a fused image which can be displayed on a monitor to provide more and better information for the driver or pilot.

  4. Camera System MTF: combining optic with detector

    Science.gov (United States)

    Andersen, Torben B.; Granger, Zachary A.

    2017-08-01

    MTF is one of the most common metrics used to quantify the resolving power of an optical component. Extensive literature is dedicated to describing methods to calculate the Modulation Transfer Function (MTF) for stand-alone optical components such as a camera lens or telescope, and some literature addresses approaches to determine an MTF for combination of an optic with a detector. The formulations pertaining to a combined electro-optical system MTF are mostly based on theory, and assumptions that detector MTF is described only by the pixel pitch which does not account for wavelength dependencies. When working with real hardware, detectors are often characterized by testing MTF at discrete wavelengths. This paper presents a method to simplify the calculation of a polychromatic system MTF when it is permissible to consider the detector MTF to be independent of wavelength.

  5. Gamma camera system with composite solid state detector

    International Nuclear Information System (INIS)

    Gerber, M.S.; Miller, D.W.

    1977-01-01

    A composite solid-state detector is described for utilization within gamma cameras. The detector's formed of an array of detector crystals, the opposed surfaces of each of which are formed incorporating an impedance-derived configuration for determining one coordinate of the location of discrete impinging photons upon the detector. A combined read-out for all detectors within the composite array is achieved through a row and column interconnection of the impedance configurations. Utilizing the read-outs for respective sides of the discrete crystals, a resultant time-constant characteristic for the composite detector crystal array remains essentially that of individual crystal detectors

  6. A practical block detector for a depth encoding PET camera

    International Nuclear Information System (INIS)

    Rogers, J.G.; Moisan, C.; Hoskinson, E.M.

    1995-10-01

    The depth-of-interaction effect in block detectors degrades the image resolution in commercial PET cameras and impedes the natural evolution of smaller, less expensive cameras. A method for correcting the measured position of each detected gamma ray by measuring its depth-of-interaction was tested and found to recover 38% of the lost resolution in a table-top 50 cm diameter camera. To obtain the desired depth sensitivity, standard commercial detectors were modified by a simple and practical process, which is suitable for mass production of the detectors. The impact of the detectors modifications on central image resolution and on the ability of the camera to correct for object scatter were also measured. (authors)

  7. The camera of the Pierre Auger Observatory Fluorescence Detector

    CERN Document Server

    Ambrosio, M; Bracci, F; Facal, P; Fonte, R; Gallo, G; Kemp, E; Matthiae, Giorgio; Nicotra, D; Privitera, P; Raia, G; Tusi, E; Vitali, G

    2002-01-01

    The Fluorescence Detector of the Pierre Auger Observatory is a set of telescopes which measure the fluorescence light emitted by atmospheric nitrogen stimulated by the cosmic-ray showers. The Camera is an array of photomultipliers positioned on the telescope focal surface. We describe the main features of the camera: the hexagonal pixels geometry on the spherical focal surface; the light collectors which complement the photomultipliers; the photomultipliers test.

  8. The camera of the Pierre Auger Observatory Fluorescence Detector

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosio, M.; Aramo, C.; Bracci, F.; Facal, P.; Fonte, R.; Gallo, G.; Kemp, E. E-mail: kemp@roma2.infn.it; Matthiae, G.; Nicotra, D.; Privitera, P.; Raia, G.; Tusi, E.; Vitali, G

    2002-02-01

    The Fluorescence Detector of the Pierre Auger Observatory is a set of telescopes which measure the fluorescence light emitted by atmospheric nitrogen stimulated by the cosmic-ray showers. The Camera is an array of photomultipliers positioned on the telescope focal surface. We describe the main features of the camera: the hexagonal pixels geometry on the spherical focal surface; the light collectors which complement the photomultipliers; the photomultipliers test.

  9. The camera of the Pierre Auger Observatory Fluorescence Detector

    International Nuclear Information System (INIS)

    Ambrosio, M.; Aramo, C.; Bracci, F.; Facal, P.; Fonte, R.; Gallo, G.; Kemp, E.; Matthiae, G.; Nicotra, D.; Privitera, P.; Raia, G.; Tusi, E.; Vitali, G.

    2002-01-01

    The Fluorescence Detector of the Pierre Auger Observatory is a set of telescopes which measure the fluorescence light emitted by atmospheric nitrogen stimulated by the cosmic-ray showers. The Camera is an array of photomultipliers positioned on the telescope focal surface. We describe the main features of the camera: the hexagonal pixels geometry on the spherical focal surface; the light collectors which complement the photomultipliers; the photomultipliers test

  10. Detector construction for a scintillation camera

    International Nuclear Information System (INIS)

    Ashe, J.B.

    1977-01-01

    An improved transducer construction for a scintillation camera in which a light conducting element is equipped with a layer of moisture impervious material is described. A scintillation crystal is thereafter positioned in optical communication with the moisture impervious layer and the remaining surfaces of the scintillation crystal are encompassed by a moisture shield. Affixing the moisture impervious layer to the light conducting element prior to attachment of the scintillation crystal reduces the requirement for mechanical strength in the moisture impervious layer and thereby allows a layer of reduced thickness to be utilized. Preferably, photodetectors are also positioned in optical communication with the light conducting element prior to positioning the scintillation crystal in contact with the impervious layer. 13 claims, 4 figures

  11. Dual energy radiography using active detector technology

    International Nuclear Information System (INIS)

    Seibert, J.A.; Poage, T.F.; Alvarez, R.E.

    1996-01-01

    A new technology has been implemented using an open-quotes active-detectorclose quotes comprised of two computed radiography (CR) imaging plates in a sandwich geometry for dual-energy radiography. This detector allows excellent energy separation, short exposure time, and high signal to noise ratio (SNR) for clinically robust open-quotes bone-onlyclose quotes and open-quotes soft-tissue onlyclose quotes images with minimum patient motion. Energy separation is achieved by two separate exposures at widely different kVp's: the high energy (120 kVp + 1.5 mm Cu filter) exposure is initiated first, followed by a short burst of intense light to erase the latent image on the front plate, and then a 50 kVp (low energy) exposure. A personal computer interfaced to the x-ray generator, filter wheel, and active detector system orchestrates the acquisition sequence within a time period of 150 msec. The front and back plates are processed using a CR readout algorithm with fixed speed and wide dynamic range. open-quotes Bone-onlyclose quotes and open-quotes soft-tissue onlyclose quotes images are calculated by geometric alignment of the two images and application of dual energy decomposition algorithms on a pixel by pixel basis. Resultant images of a calibration phantom demonstrate an increase of SNR 2 / dose by ∼73 times when compared to a single exposure open-quotes passive-detectorclose quotes comprised of CR imaging plates, and an ∼8 fold increase compared to a screen-film dual-energy cassette comprised of different phosphor compounds. In conclusion, dual energy imaging with open-quotes active detectorclose quotes technology is clinically feasible and can provide substantial improvements over conventional methods for dual-energy radiography

  12. Dual-camera design for coded aperture snapshot spectral imaging.

    Science.gov (United States)

    Wang, Lizhi; Xiong, Zhiwei; Gao, Dahua; Shi, Guangming; Wu, Feng

    2015-02-01

    Coded aperture snapshot spectral imaging (CASSI) provides an efficient mechanism for recovering 3D spectral data from a single 2D measurement. However, since the reconstruction problem is severely underdetermined, the quality of recovered spectral data is usually limited. In this paper we propose a novel dual-camera design to improve the performance of CASSI while maintaining its snapshot advantage. Specifically, a beam splitter is placed in front of the objective lens of CASSI, which allows the same scene to be simultaneously captured by a grayscale camera. This uncoded grayscale measurement, in conjunction with the coded CASSI measurement, greatly eases the reconstruction problem and yields high-quality 3D spectral data. Both simulation and experimental results demonstrate the effectiveness of the proposed method.

  13. Infrared detectors and test technology of cryogenic camera

    Science.gov (United States)

    Yang, Xiaole; Liu, Xingxin; Xing, Mailing; Ling, Long

    2016-10-01

    Cryogenic camera which is widely used in deep space detection cools down optical system and support structure by cryogenic refrigeration technology, thereby improving the sensitivity. Discussing the characteristics and design points of infrared detector combined with camera's characteristics. At the same time, cryogenic background test systems of chip and detector assembly are established. Chip test system is based on variable cryogenic and multilayer Dewar, and assembly test system is based on target and background simulator in the thermal vacuum environment. The core of test is to establish cryogenic background. Non-uniformity, ratio of dead pixels and noise of test result are given finally. The establishment of test system supports for the design and calculation of infrared systems.

  14. Dead time of dual detector tools

    International Nuclear Information System (INIS)

    Czubek, J.A.

    1994-01-01

    A theory of the dead time for the dual detector nuclear tool with the analogue signal transmission is given in the paper. At least two different times exist in such tools: the dead time of detectors (for final computation they assumed identical to each other) and the dead time of the signal transmission set-up. A method of two radioactive sources is proposed to measure these two different dead times. When the times used for measuring every countrate needed in the dead time determination algorithm are taken into account, the statistical accuracy of the dead time determination can be obtained. These estimations are performed by the computer simulation method. Two codes have been designed: DEADT2D (DEAD Time for 2 Detectors) and DEADT2DS (DEAD Time for 2 Detectors with Statistics). The first code calculates the dead time based on the recorded countrates only, the second is doing a 'simulation job' and provides information on the statistical distribution of the observed dead times. The theory and the numerical solutions were checked both by the simulation calculations and by the experiments performed with the ODSN-102 tool (the experiments were performed by T. Zorski). (Author)

  15. Monte Carlo simulation for dual head gamma camera

    International Nuclear Information System (INIS)

    Osman, Yousif Bashir Soliman

    2015-12-01

    Monte Carlo (MC) simulation technique was used widely in medical physics applications. In nuclear medicine MC was used to design new medical imaging devices such as positron emission tomography (PET), gamma camera and single photon emission computed tomography (SPECT). Also it can be used to study the factors affecting image quality and internal dosimetry, Gate is on of monte Carlo code that has a number of advantages for simulation of SPECT and PET. There is a limit accessibilities in machines which are used in clinics because of the work load of machines. This makes it hard to evaluate some factors effecting machine performance which must be evaluated routinely. Also because of difficulties of carrying out scientific research and training of students, MC model can be optimum solution for the problem. The aim of this study was to use gate monte Carlo code to model Nucline spirit, medico dual head gamma camera hosted in radiation and isotopes center of Khartoum which is equipped with low energy general purpose LEGP collimators. This was used model to evaluate spatial resolution and sensitivity which is important factor affecting image quality and to demonstrate the validity of gate by comparing experimental results with simulation results on spatial resolution. The gate model of Nuclide spirit, medico dual head gamma camera was developed by applying manufacturer specifications. Then simulation was run. In evaluation of spatial resolution the FWHM was calculated from image profile of line source of Tc 99m gammas emitter of energy 140 KeV at different distances from modeled camera head at 5,10,15,20,22,27,32,37 cm and for these distances the spatial resolution was founded to be 5.76, 7.73, 10.7, 13.8, 14.01,16.91, 19.75 and 21.9 mm, respectively. These results showed a decrement of spatial resolution with increase of the distance between object (line source) and collimator in linear manner. FWHM calculated at 10 cm was compared with experimental results. The

  16. First Test Of A New High Resolution Positron Camera With Four Area Detectors

    Science.gov (United States)

    van Laethem, E.; Kuijk, M.; Deconinck, Frank; van Miert, M.; Defrise, Michel; Townsend, D.; Wensveen, M.

    1989-10-01

    A PET camera consisting of two pairs of parallel area detectors has been installed at the cyclotron unit of VUB. The detectors are High Density Avalanche Chambers (HIDAC) wire-chambers with a stack of 4 or 6 lead gamma-electron converters, the sensitive area being 30 by 30 cm. The detectors are mounted on a commercial gantry allowing a 180 degree rotation during acquisition, as needed for a fully 3D image reconstruction. The camera has been interfaced to a token-ring computer network consisting of 5 workstations among which the various tasks (acquisition, reconstruction, display) can be distributed. Each coincident event is coded in 48 bits and is transmitted to the computer bus via a 512 kbytes dual ported buffer memory allowing data rates of up to 50 kHz. Fully 3D image reconstruction software has been developed, and includes new reconstruction algorithms allowing a better utilization of the available projection data. Preliminary measurements and imaging of phantoms and small animals (with 18FDG) have been performed with two of the four detectors mounted on the gantry. They indicate the expected 3D isotropic spatial resolution of 3.5 mm (FWHM, line source in air) and a sensitivity of 4 cps/μCi for a centred point source in air, corresponding to typical data rates of a few kHz. This latter figure is expected to improve by a factor of 4 after coupling of the second detector pair, since the coincidence sensitivity of this second detector pair is a factor 3 higher than that of the first one.

  17. Single-Band and Dual-Band Infrared Detectors

    Science.gov (United States)

    Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor); Soibel, Alexander (Inventor); Nguyen, Jean (Inventor); Khoshakhlagh, Arezou (Inventor)

    2017-01-01

    Bias-switchable dual-band infrared detectors and methods of manufacturing such detectors are provided. The infrared detectors are based on a back-to-back heterojunction diode design, where the detector structure consists of, sequentially, a top contact layer, a unipolar hole barrier layer, an absorber layer, a unipolar electron barrier, a second absorber, a second unipolar hole barrier, and a bottom contact layer. In addition, by substantially reducing the width of one of the absorber layers, a single-band infrared detector can also be formed.

  18. Development of Strained-Layer Superlattice (SLS) IR Detector Camera

    Data.gov (United States)

    National Aeronautics and Space Administration — Strained Layer Superlattice (SLS) detectors are a new class of detectors which may be the next generation of band-gap engineered, large format infrared detector...

  19. Dual concentric crystal low energy photon detector

    Science.gov (United States)

    Guilmette, R.A.

    A photon detector for biological samples includes a block of NaI(T1) having a hole containing a thin walled cylinder of CsI(T1). At least three photo multiplier tubes are evenly spaced around the parameter of the block. Biological samples are placed within the hole, and emissions which are sensed by at least two of the photo multipliers from only the NaI(T1) detector are counted.

  20. A practical block detector for a depth-encoding PET camera

    International Nuclear Information System (INIS)

    Rogers, J.G.; Moisan, C.; Hoskinson, E.M.; Andreaco, M.S.; Williams, C.W.; Nutt, R.

    1996-01-01

    The depth-of-interaction effect in block detectors degrades the image resolution in commercial PET cameras and impedes the natural evolution of smaller, less expensive cameras. A method for correcting the measured position of each detected gamma ray by measuring its depth-of-interaction was tested and found to recover 38% of the lost resolution at 7.5 cm radius in a tabletop, 50-cm-diameter camera. To obtain the desired depth sensitivity, standard commercial detectors were modified by a simple and practical process that is suitable for mass production of the detectors. The impact of the detector modifications on central image resolution and on the ability of the camera to correct for object scatter were also measured

  1. Development of a dual MCP framing camera for high energy x-rays

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, N., E-mail: izumi2@llnl.gov; Hall, G. N.; Carpenter, A. C.; Allen, F. V.; Cruz, J. G.; Felker, B.; Hargrove, D.; Holder, J.; Lumbard, A.; Montesanti, R.; Palmer, N. E.; Piston, K.; Stone, G.; Thao, M.; Vern, R.; Zacharias, R.; Landen, O. L.; Tommasini, R.; Bradley, D. K.; Bell, P. M. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

    2014-11-15

    Recently developed diagnostic techniques at LLNL require recording backlit images of extremely dense imploded plasmas using hard x-rays, and demand the detector to be sensitive to photons with energies higher than 50 keV [R. Tommasini et al., Phys. Phys. Plasmas 18, 056309 (2011); G. N. Hall et al., “AXIS: An instrument for imaging Compton radiographs using ARC on the NIF,” Rev. Sci. Instrum. (these proceedings)]. To increase the sensitivity in the high energy region, we propose to use a combination of two MCPs. The first MCP is operated in a low gain regime and works as a thick photocathode, and the second MCP works as a high gain electron multiplier. We tested the concept of this dual MCP configuration and succeeded in obtaining a detective quantum efficiency of 4.5% for 59 keV x-rays, 3 times larger than with a single plate of the thickness typically used in NIF framing cameras.

  2. Image dynamic range test and evaluation of Gaofen-2 dual cameras

    Science.gov (United States)

    Zhang, Zhenhua; Gan, Fuping; Wei, Dandan

    2015-12-01

    In order to fully understand the dynamic range of Gaofen-2 satellite data and support the data processing, application and next satellites development, in this article, we evaluated the dynamic range by calculating some statistics such as maximum ,minimum, average and stand deviation of four images obtained at the same time by Gaofen-2 dual cameras in Beijing area; then the maximum ,minimum, average and stand deviation of each longitudinal overlap of PMS1,PMS2 were calculated respectively for the evaluation of each camera's dynamic range consistency; and these four statistics of each latitudinal overlap of PMS1,PMS2 were calculated respectively for the evaluation of the dynamic range consistency between PMS1 and PMS2 at last. The results suggest that there is a wide dynamic range of DN value in the image obtained by PMS1 and PMS2 which contains rich information of ground objects; in general, the consistency of dynamic range between the single camera images is in close agreement, but also a little difference, so do the dual cameras. The consistency of dynamic range between the single camera images is better than the dual cameras'.

  3. Commissioning of the advanced light source dual-axis streak camera

    International Nuclear Information System (INIS)

    Hinkson, J.; Keller, R.; Byrd, J.

    1997-05-01

    A dual-axis camera, Hamamatsu model C5680, has been installed on the Advanced Light Source photon-diagnostics beam-line to investigate electron-beam parameters. During its commissioning process, the camera has been used to measure single-bunch length vs. current, relative bunch charge in adjacent RF buckets, and bunchphase stability. In this paper the authors describe the visible-light branch of the diagnostics beam-line, the streak-camera installation, and the timing electronics. They will show graphical results of beam measurements taken during a variety of accelerator conditions

  4. The HERMES dual-radiator RICH detector

    CERN Document Server

    Jackson, H E

    2003-01-01

    The HERMES experiment emphasizes measurements of semi-inclusive deep-inelastic scattering. Most of the hadrons produced lie between 2 and 10 GeV, a region in which it had not previously been feasible to separate pions, kaons, and protons with standard particle identification (PID) techniques. The recent development of new clear, large, homogeneous and hydrophobic silica aerogel material with a low index of refraction offered the means to apply RICH PID techniques to this difficult momentum region. The HERMES instrument uses two radiators, C sub 4 F sub 1 sub 0 , a heavy fluorocarbon gas, and a wall of silica aerogel tiles. A lightweight spherical mirror constructed using a newly perfected technique to make resin-coated carbon-fiber surfaces of optical quality provides optical focusing on a photon detector consisting of 1934 photomultiplier tubes (PMT) for each detector half. The PMT array is held in a soft steel matrix to provide shielding against the residual field of the main spectrometer magnet. Ring recon...

  5. 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.

  6. Density and water content measurement with two dual detector probes

    International Nuclear Information System (INIS)

    Cariou, J.; Menard, J.

    1980-01-01

    The ''Laboratoires des Ponts et Chaussees'' have developed an electronic device for geological prospections. This system includes gamma-gamma and neutron-neutron probes for continuous measurement in borehole down to one hundred meters. It is used, as well to measure the density and the water content in the field of soil mechanic engineering. When the diameter is not constant all along the borehole the two probes have to use a dual detector procedure. When constant, a simple detector procedure is sufficient to obtain density and water content. Two examples show the possibilities of this apparatus, particularly to control the borehole diameter and the soil chemical composition [fr

  7. Development of dual sensor hand-held detector

    Science.gov (United States)

    Sezgin, Mehmet

    2010-04-01

    In this paper hand-held dual sensor detector development requirements are considered dedicated to buried object detection. Design characteristics of such a system are categorized and listed. Hardware and software structures, ergonomics, user interface, environmental and EMC/EMI tests to be applied and performance test issues are studied. Main properties of the developed system (SEZER) are presented, which contains Metal Detector (MD) and Ground Penetrating Radar (GPR). The realized system has ergonomic structure and can detect both metallic and non-metallic buried objects. Moreover classification of target is possible if it was defined to the signal processing software in learning phase.

  8. Calibration of a dual-PTZ camera system for stereo vision

    Science.gov (United States)

    Chang, Yau-Zen; Hou, Jung-Fu; Tsao, Yi Hsiang; Lee, Shih-Tseng

    2010-08-01

    In this paper, we propose a calibration process for the intrinsic and extrinsic parameters of dual-PTZ camera systems. The calibration is based on a complete definition of six coordinate systems fixed at the image planes, and the pan and tilt rotation axes of the cameras. Misalignments between estimated and ideal coordinates of image corners are formed into cost values to be solved by the Nelder-Mead simplex optimization method. Experimental results show that the system is able to obtain 3D coordinates of objects with a consistent accuracy of 1 mm when the distance between the dual-PTZ camera set and the objects are from 0.9 to 1.1 meters.

  9. Dual photon absorptiometry for bone mineral measurements using a gamma camera

    International Nuclear Information System (INIS)

    Valkema, R.; Prpic, H.; Blokland, J.A.K.; Camps, J.A.J.; Papapoulos, S.E.; Bijvoet, O.L.M.; Pauwels, E.K.J.

    1994-01-01

    A gamma camera was equipped with a special collimator and arm assembly for bone mineral measurements with dual photon absorptiometry (DPA). The system was evaluated in vitro and in vivo and compared both with a rectilinear DPA and a dual energy X-ray (DEXA) system. All 3 systems showed a linear response in measurements of 4 vials, containing different amounts of hydroxyapatite. Phantom measurements with the gamma camera system showed a precision of 1.6% to 2.8%. Results obtained in 8 healthy volunteers with rectilinear and gamma camera systems were well correlated (R 2 = 0.78). With the photon beam directed from posterior to anterior, the separation of vertebrae was easy with the gamma camera system. We conclude that bone mineral measurements can be made with a gamma camera for assessment of fracture risk and in the decision process whether a patient needs treatment or not. For follow-up, the precision of DPA with a gamma camera is inadequate. (orig.)

  10. Characterization of highly multiplexed monolithic PET / gamma camera detector modules

    Science.gov (United States)

    Pierce, L. A.; Pedemonte, S.; DeWitt, D.; MacDonald, L.; Hunter, W. C. J.; Van Leemput, K.; Miyaoka, R.

    2018-04-01

    PET detectors use signal multiplexing to reduce the total number of electronics channels needed to cover a given area. Using measured thin-beam calibration data, we tested a principal component based multiplexing scheme for scintillation detectors. The highly-multiplexed detector signal is no longer amenable to standard calibration methodologies. In this study we report results of a prototype multiplexing circuit, and present a new method for calibrating the detector module with multiplexed data. A 50 × 50 × 10 mm3 LYSO scintillation crystal was affixed to a position-sensitive photomultiplier tube with 8 × 8 position-outputs and one channel that is the sum of the other 64. The 65-channel signal was multiplexed in a resistive circuit, with 65:5 or 65:7 multiplexing. A 0.9 mm beam of 511 keV photons was scanned across the face of the crystal in a 1.52 mm grid pattern in order to characterize the detector response. New methods are developed to reject scattered events and perform depth-estimation to characterize the detector response of the calibration data. Photon interaction position estimation of the testing data was performed using a Gaussian Maximum Likelihood estimator and the resolution and scatter-rejection capabilities of the detector were analyzed. We found that using a 7-channel multiplexing scheme (65:7 compression ratio) with 1.67 mm depth bins had the best performance with a beam-contour of 1.2 mm FWHM (from the 0.9 mm beam) near the center of the crystal and 1.9 mm FWHM near the edge of the crystal. The positioned events followed the expected Beer–Lambert depth distribution. The proposed calibration and positioning method exhibited a scattered photon rejection rate that was a 55% improvement over the summed signal energy-windowing method.

  11. Statistical decision making with a dual-detector probe

    International Nuclear Information System (INIS)

    Hickernell, T.S.

    1988-01-01

    Conventional imaging techniques for cancer detection have difficulty finding small, deep tumors. Single-detector radiation probes have been developed to search for deep lesions in a patient who has been given a tumor-seeking radiopharmaceutical. These probes perform poorly, however, when the background activity in the patient varies greatly from site to site. We have developed a surgical dual-detector probe that solves the problem of background activity variation, by simultaneously monitoring counts from a region of interest and counts from adjacent normal tissue. A comparison of counts from the detectors can reveal the class of tissue, tumor or normal, in the region of interest. In this study, we apply methods from statistical decision theory and derive a suitable comparison of counts to help us decide whether a tumor is present in the region of interest. We use the Hotelling trace criterion with a few assumptions to find a linear discriminant function, which can be reduced to a normalized subtraction of the counts for large background count-rate variations. Using a spatial response map of the dual probe, a computer torso phantom, and estimates of activity distribution, we simulate a surgical staging procedure to test the dual probe and the discriminant functions

  12. Dual detector neutron lifetime log: theory and practical applications

    International Nuclear Information System (INIS)

    Serpas, C.J.; Wichmann, P.A.; Fertl, W.H.; DeVries, M.R.; Rndall, R.R.

    1977-01-01

    The Neutron Lifetime Log instrumentation has continued to evolve and now is equipped with dual detectors for increased ease in gas detection and also a ratio response for a simultaneous porosity determination. A good deal of experimentation was involved to minimize both lithology and salinity effects on the porosity indication. This paper contains a discussion of the theory and concepts related to the application of the Dual Detector Neutron Lifetime Log (DNLL). It is important to note that with these advances the recording of thermal neutron capture cross section (Σ) remains consistent with the past measurements of earlier generations of instruments as the most accurate determination of this parameter. A number of field examples of the newly logged results are shown. These field cases include Dual Detector NLL's run thru the drill strings of highly deviated holes when difficulties were encountered in getting conventional open hole logs to bottom, logs thru open perforations and hot radioactive zones, comparisons of the large and small diameter instruments, logs with anomalous fluids in the annulus, logs thru multiple casing strings, and a number of other examples

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

    International Nuclear Information System (INIS)

    Kim, Joshua; Zhang, Tiezhi; Lu, Weiguo

    2014-01-01

    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. (paper)

  14. 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.

  15. Optimisation of a dual head semiconductor Compton camera using Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Harkness, L.J. [Department of Physics, University of Liverpool, Oliver Lodge Laboratory, Liverpool L697ZE (United Kingdom)], E-mail: ljh@ns.ph.liv.ac.uk; Boston, A.J.; Boston, H.C.; Cooper, R.J.; Cresswell, J.R.; Grint, A.N.; Nolan, P.J.; Oxley, D.C.; Scraggs, D.P. [Department of Physics, University of Liverpool, Oliver Lodge Laboratory, Liverpool L697ZE (United Kingdom); Beveridge, T.; Gillam, J. [School of Physics and Materials Engineering, Monash University, Melbourne (Australia); Lazarus, I. [STFC Daresbury Laboratory, Warrington, Cheshire (United Kingdom)

    2009-06-01

    Conventional medical gamma-ray camera systems utilise mechanical collimation to provide information on the position of an incident gamma-ray photon. Systems that use electronic collimation utilising Compton image reconstruction techniques have the potential to offer huge improvements in sensitivity. Position sensitive high purity germanium (HPGe) detector systems are being evaluated as part of a single photon emission computed tomography (SPECT) Compton camera system. Data have been acquired from the orthogonally segmented planar SmartPET detectors, operated in Compton camera mode. The minimum gamma-ray energy which can be imaged by the current system in Compton camera configuration is 244 keV due to the 20 mm thickness of the first scatter detector which causes large gamma-ray absorption. A simulation package for the optimisation of a new semiconductor Compton camera has been developed using the Geant4 toolkit. This paper will show results of preliminary analysis of the validated Geant4 simulation for gamma-ray energies of SPECT, 141 keV.

  16. High-performance dual-speed CCD camera system for scientific imaging

    Science.gov (United States)

    Simpson, Raymond W.

    1996-03-01

    Traditionally, scientific camera systems were partitioned with a `camera head' containing the CCD and its support circuitry and a camera controller, which provided analog to digital conversion, timing, control, computer interfacing, and power. A new, unitized high performance scientific CCD camera with dual speed readout at 1 X 106 or 5 X 106 pixels per second, 12 bit digital gray scale, high performance thermoelectric cooling, and built in composite video output is described. This camera provides all digital, analog, and cooling functions in a single compact unit. The new system incorporates the A/C converter, timing, control and computer interfacing in the camera, with the power supply remaining a separate remote unit. A 100 Mbyte/second serial link transfers data over copper or fiber media to a variety of host computers, including Sun, SGI, SCSI, PCI, EISA, and Apple Macintosh. Having all the digital and analog functions in the camera made it possible to modify this system for the Woods Hole Oceanographic Institution for use on a remote controlled submersible vehicle. The oceanographic version achieves 16 bit dynamic range at 1.5 X 105 pixels/second, can be operated at depths of 3 kilometers, and transfers data to the surface via a real time fiber optic link.

  17. Characterization of highly multiplexed monolithic PET / gamma camera detector modules

    DEFF Research Database (Denmark)

    Pierce, L. A.; Pedemonte, Stefano; Dewitt, Sharon

    2018-01-01

    tube with 8 × 8 position-outputs and one channel that is the sum of the other 64. The 65-channel signal was multiplexed in a resistive circuit, with 65:5 or 65:7 multiplexing. A 0.9 mm beam of 511 keV photons was scanned across the face of the crystal in a 1.52 mm grid pattern in order to characterize...... and scatter-rejection capabilities of the detector were analyzed. We found that using a 7-channel multiplexing scheme (65:7 compression ratio) with 1.67 mm depth bins had the best performance with a beam-contour of 1.2 mm FWHM (from the 0.9 mm beam) near the center of the crystal and 1.9 mm FWHM near the edge...... the detector response. New methods are developed to reject scattered events and perform depthestimation to characterize the detector response of the calibration data. Photon interaction position estimation of the testing data was performed using a Gaussian Maximum Likelihood estimator and the resolution...

  18. Performance of low-cost X-ray area detectors with consumer digital cameras

    International Nuclear Information System (INIS)

    Panna, A.; Gomella, A.A.; Harmon, K.J.; Chen, P.; Miao, H.; Bennett, E.E.; Wen, H.

    2015-01-01

    We constructed X-ray detectors using consumer-grade digital cameras coupled to commercial X-ray phosphors. Several detector configurations were tested against the Varian PaxScan 3024M (Varian 3024M) digital flat panel detector. These include consumer cameras (Nikon D800, Nikon D700, and Nikon D3X) coupled to a green emission phosphor in a back-lit, normal incidence geometry, and in a front-lit, oblique incidence geometry. We used the photon transfer method to evaluate detector sensitivity and dark noise, and the edge test method to evaluate their spatial resolution. The essential specifications provided by our evaluation include discrete charge events captured per mm 2 per unit exposure surface dose, dark noise in equivalents of charge events per pixel, and spatial resolution in terms of the full width at half maximum (FWHM) of the detector's line spread function (LSF). Measurements were performed using a tungsten anode X-ray tube at 50 kVp. The results show that the home-built detectors provide better sensitivity and lower noise than the commercial flat panel detector, and some have better spatial resolution. The trade-off is substantially smaller imaging areas. Given their much lower costs, these home-built detectors are attractive options for prototype development of low-dose imaging applications

  19. Iterative Refinement of Transmission Map for Stereo Image Defogging Using a Dual Camera Sensor

    Directory of Open Access Journals (Sweden)

    Heegwang Kim

    2017-12-01

    Full Text Available Recently, the stereo imaging-based image enhancement approach has attracted increasing attention in the field of video analysis. This paper presents a dual camera-based stereo image defogging algorithm. Optical flow is first estimated from the stereo foggy image pair, and the initial disparity map is generated from the estimated optical flow. Next, an initial transmission map is generated using the initial disparity map. Atmospheric light is then estimated using the color line theory. The defogged result is finally reconstructed using the estimated transmission map and atmospheric light. The proposed method can refine the transmission map iteratively. Experimental results show that the proposed method can successfully remove fog without color distortion. The proposed method can be used as a pre-processing step for an outdoor video analysis system and a high-end smartphone with a dual camera system.

  20. Iterative Refinement of Transmission Map for Stereo Image Defogging Using a Dual Camera Sensor.

    Science.gov (United States)

    Kim, Heegwang; Park, Jinho; Park, Hasil; Paik, Joonki

    2017-12-09

    Recently, the stereo imaging-based image enhancement approach has attracted increasing attention in the field of video analysis. This paper presents a dual camera-based stereo image defogging algorithm. Optical flow is first estimated from the stereo foggy image pair, and the initial disparity map is generated from the estimated optical flow. Next, an initial transmission map is generated using the initial disparity map. Atmospheric light is then estimated using the color line theory. The defogged result is finally reconstructed using the estimated transmission map and atmospheric light. The proposed method can refine the transmission map iteratively. Experimental results show that the proposed method can successfully remove fog without color distortion. The proposed method can be used as a pre-processing step for an outdoor video analysis system and a high-end smartphone with a dual camera system.

  1. A directional fast neutron detector using scintillating fibers and an intensified CCD camera system

    International Nuclear Information System (INIS)

    Holslin, Daniel; Armstrong, A.W.; Hagan, William; Shreve, David; Smith, Scott

    1994-01-01

    We have been developing and testing a scintillating fiber detector (SFD) for use as a fast neutron sensor which can discriminate against neutrons entering at angles non-parallel to the fiber axis (''directionality''). The detector/convertor component is a fiber bundle constructed of plastic scintillating fibers each measuring 10 cm long and either 0.3 mm or 0.5 mm in diameter. Extensive Monte Carlo simulations were made to optimize the bundle response to a range of fast neutron energies and to intense fluxes of high energy gamma-rays. The bundle is coupled to a set of gamma-ray insenitive electro-optic intensifiers whose output is viewed by a CCD camera directly coupled to the intensifiers. Two types of CCD cameras were utilized: 1) a standard, interline RS-170 camera with electronic shuttering and 2) a high-speed (up to 850 frame/s) field-transfer camera. Measurements of the neutron detection efficiency and directionality were made using 14 MeV neutrons, and the response to gamma-rays was performed using intense fluxes from radioisotopic sources (up to 20 R/h). Recently, the detector was constructed and tested using a large 10 cm by 10 cm square fiber bundle coupled to a 10 cm diameter GEN I intensifier tube. We present a description of the various detector systems and report the results of experimental tests. ((orig.))

  2. A study on the optimization of optical guide of gamma camera detector

    International Nuclear Information System (INIS)

    Chung, Yong Hyun; Cho, Gyu Seong; Kim, Ho Kyung; Lee, Wan No; Kim, Young Soo

    2000-01-01

    An optical guide, which is a light guide located between NaI(Tl) scintillation-crystal and array of photo-multiplier tubes (PMTs) in the gamma camera detector system, is an essential component to deliver the spatial information recorded in scintillator to the PMTs. Without the optical guide, the spatial information within the range of a single PMT could not be obtained. For the design of the optimal optical guide, it is necessary to characterize its properties, especially sensitivity and spatial resolution of detector. In this study, the thickness and the refractive index of optical guide, which affect not only on the sensitivity but also on the spatial resolution of gamma-camera detector, were investigated by using Monte Carlo simulation. A 12'x12'x3/8' NaI(Tl) and 23 PMTs with each 5' diameter were considered as a gamma-camera detector components. Interactions of optical photons in the scintillator and the optical guide were simulated using a commercial code DETECT97, and the spatial resolution, mainly interfered by the intrinsic inward distortion within the PMT, was investigated using our own ANGER program, which was developed to calculate positions of incident photons in the gamma camera. From the simulation results, it was found that an optical guide with 1.6 of refractive index and 10 mm of thickness give maximum sensitivity and minimum spatial distortion, respectively

  3. Development of a Compton camera for medical applications based on silicon strip and scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Krimmer, J., E-mail: j.krimmer@ipnl.in2p3.fr [Institut de Physique Nucléaire de Lyon, Université de Lyon, Université Lyon 1, CNRS/IN2P3 UMR 5822, 69622 Villeurbanne cedex (France); Ley, J.-L. [Institut de Physique Nucléaire de Lyon, Université de Lyon, Université Lyon 1, CNRS/IN2P3 UMR 5822, 69622 Villeurbanne cedex (France); Abellan, C.; Cachemiche, J.-P. [Aix-Marseille Université, CNRS/IN2P3, CPPM UMR 7346, 13288 Marseille (France); Caponetto, L.; Chen, X.; Dahoumane, M.; Dauvergne, D. [Institut de Physique Nucléaire de Lyon, Université de Lyon, Université Lyon 1, CNRS/IN2P3 UMR 5822, 69622 Villeurbanne cedex (France); Freud, N. [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA - Lyon, Université Lyon 1, Centre Léon Bérard (France); Joly, B.; Lambert, D.; Lestand, L. [Clermont Université, Université Blaise Pascal, CNRS/IN2P3, Laboratoire de Physique Corpusculaire, BP 10448, F-63000 Clermont-Ferrand (France); Létang, J.M. [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA - Lyon, Université Lyon 1, Centre Léon Bérard (France); Magne, M. [Clermont Université, Université Blaise Pascal, CNRS/IN2P3, Laboratoire de Physique Corpusculaire, BP 10448, F-63000 Clermont-Ferrand (France); and others

    2015-07-01

    A Compton camera is being developed for the purpose of ion-range monitoring during hadrontherapy via the detection of prompt-gamma rays. The system consists of a scintillating fiber beam tagging hodoscope, a stack of double sided silicon strip detectors (90×90×2 mm{sup 3}, 2×64 strips) as scatter detectors, as well as bismuth germanate (BGO) scintillation detectors (38×35×30 mm{sup 3}, 100 blocks) as absorbers. The individual components will be described, together with the status of their characterization.

  4. Expanding of FOV of NaI(Tl) gamma camera detectors-Is it possible?

    International Nuclear Information System (INIS)

    Gayshan, Vadim L.; Gektin, A.V.; Boyarintsev, A.; Pedash, V.

    2006-01-01

    Every gamma camera detector used for medical imaging of conventional design faces the problem of distorted or no information readout at the areas closer to the edge of detectors. Obtaining position and energy information becomes almost impossible at distance 0-12 of PMT size from the edge. Therefore, in some designs were proposed losing of edge energy resolution while improving in spatial uniformity when it comes to imaging at the edges. This work is dedicated to understanding of the problem, mathematical simulations, practical tests and recommendations to build detectors with larger usable FOV without increasing in dimensions. To study the problem we built the test jig with linear motion source and readout electronics to simulate gamma cameras of PMTs. Based on simulation results the idea of modifying of crystal shape combined with specific light redirection system of baffles was tested and allowed to expand usable FOV. The results are presented and showed that for traditional NaI(Tl) scintillators using 2'' PMT may be possible to obtain relatively good spatial resolution starting from 4-5mm from the edge of a detector. The question of economical efficiency of proposed method is being investigated and a special detector manufacturing technology must be developed to accommodate this. While we believe that achieved results are very important for small size detectors (<20cm) they could be beneficial even for larger detectors used in whole body imaging systems

  5. Fundamental study of dynamic ECT by dual detector gammacamera system

    International Nuclear Information System (INIS)

    Kakegawa, M.; Matsui, S.; Maeda, H.; Takeda, K.; Nakagawa, T.

    1982-01-01

    The improvement of image quality of reconstructed image by the simple pre-processing of projections is studied. Using the improved algorithm and dual detector gammacamera system, the possibility of dynamic ECT is studied. As shown in clinical examples, renal flow study using Tc-99m-DTPA, dynamic ECT imaging is possible with measuring time of 1 or 2 minutes. By this method cortex and medulla are separately imaged and each function can be analyzed more precisely. Using high sensitive collimator it will be possible to take ECT images every 30 sec. with little resolution loss quantitative three dimensional time activity analysis is under study

  6. A dual tech gem for future neutrino detectors

    CERN Multimedia

    Stefania Pandolfi

    2016-01-01

    Innovative technologies for next-generation neutrino detectors are currently being tested in the CERN Neutrino Platform project WA105.   Installation of the WA105 cryostat. (Image : Maximilien Brice/ CERN) The activities under way in the framework of the CERN Neutrino Platform are multiple and restless. Along with the refurbishment of ICARUS, another project is making great strides towards its completion: WA105. In spite of the not-so-expressive name, the technology being tested in this prototype is unprecedented. WA105, presently at an advanced state of assembly at CERN, is a 3x1x1-metre, 25-tonne “dual-phase” liquid argon time projection chamber (DLAr-TPC) demonstrator. It has been conceived in the quest to solve the technological problems related to the next generation of neutrino detectors, whose dimensions need to be gigantic in order to thoroughly study the phenomenon of neutrino oscillations. Indeed, a major new international project called DUNE (Deep Underground Neutri...

  7. Preliminary report on the development of a high resolution PET camera using semiconductor detectors

    International Nuclear Information System (INIS)

    Kikuchi, Yohei; Ishii, Keizo; Yamazaki, Hiromichi; Matsuyama, Shigeo; Yamaguchi, Takashi; Yamamoto, Yusuke; Sato, Takemi; Aoki, Yasushi; Aoki, Kenichi

    2005-01-01

    We are developing a PET camera using small semiconductor detectors, whose resolution is equivalent to the physical limit of spatial resolution. First, a coincidence system of 16 Schottky CdTe detectors of 0.5 mm width obtained a resolution of <1 mm and it was confirmed that the Schottky CdTe detector is suitable for high resolution PET. Next, the performance of a pair of 32 channel CdTe arrays (1.2 mm width per channel) was investigated for the development of the prototype of high resolution PET. The time resolution between opposing detector pair was 13 ns (FWHM) when high voltage (700 V) was applied. The image of a 0.6 mm diameter point source was obtained in an experiment with opposing detector arrays using four channels, indicating that, a higher resolution can be achieved with the 32 channel CdTe array

  8. High-resolution Compton cameras based on Si/CdTe double-sided strip detectors

    International Nuclear Information System (INIS)

    Odaka, Hirokazu; Ichinohe, Yuto; Takeda, Shin'ichiro; Fukuyama, Taro; Hagino, Koichi; Saito, Shinya; Sato, Tamotsu; Sato, Goro; Watanabe, Shin; Kokubun, Motohide; Takahashi, Tadayuki; Yamaguchi, Mitsutaka

    2012-01-01

    We have developed a new Compton camera based on silicon (Si) and cadmium telluride (CdTe) semiconductor double-sided strip detectors (DSDs). The camera consists of a 500-μm-thick Si-DSD and four layers of 750-μm-thick CdTe-DSDs all of which have common electrode configuration segmented into 128 strips on each side with pitches of 250μm. In order to realize high angular resolution and to reduce size of the detector system, a stack of DSDs with short stack pitches of 4 mm is utilized to make the camera. Taking advantage of the excellent energy and position resolutions of the semiconductor devices, the camera achieves high angular resolutions of 4.5° at 356 keV and 3.5° at 662 keV. To obtain such high resolutions together with an acceptable detection efficiency, we demonstrate data reduction methods including energy calibration using Compton scattering continuum and depth sensing in the CdTe-DSD. We also discuss imaging capability of the camera and show simultaneous multi-energy imaging.

  9. Modeling indirect detectors for performance optimization of a digital mammographic detector for dual energy applications

    International Nuclear Information System (INIS)

    Martini, N; Koukou, V; Sotiropoulou, P; Nikiforidis, G; Kalyvas, N; Michail, C; Valais, I; Kandarakis, I; Fountos, G; Bakas, A

    2015-01-01

    Dual Energy imaging is a promising method for visualizing masses and microcalcifications in digital mammography. The advent of two X-ray energies (low and high) requires a suitable detector. The scope of this work is to determine optimum detector parameters for dual energy applications. The detector was modeled through the linear cascaded (LCS) theory. It was assumed that a phosphor material was coupled to a CMOS photodetector (indirect detection). The pixel size was 22.5 μm. The phosphor thickness was allowed to vary between 20mg/cm 2 and 160mg/cm 2 The phosphor materials examined where Gd 2 O 2 S:Tb and Gd 2 O 2 S:Eu. Two Tungsten (W) anode X-ray spectra at 35 kV (filtered with 100 μm Palladium (Pd)) and 70 kV (filtered with 800 pm Ytterbium (Yb)), corresponding to low and high energy respectively, were considered to be incident on the detector. For each combination the contrast- to-noise ratio (CNR) and the detector optical gain (DOG), showing the sensitivity of the detector, were calculated. The 40 mg/cm 2 and 70 mg/cm 2 Gd 2 O 2 S:Tb exhibited the higher DOG values for the low and high energy correspondingly. Higher CNR between microcalcification and mammary gland exhibited the 70mg/cm 2 and the 100mg/cm 2 Gd 2 O 2 S:Tb for the low and the high energy correspondingly

  10. Dual-sided microstructured semiconductor neutron detectors (DSMSNDs)

    International Nuclear Information System (INIS)

    Fronk, Ryan G.; Bellinger, Steven L.; Henson, Luke C.; Ochs, Taylor R.; Smith, Colten T.; Kenneth Shultis, J.; McGregor, Douglas S.

    2015-01-01

    Microstructured semiconductor neutron detectors (MSNDs) have in recent years received much interest as high-efficiency replacements for thin-film-coated thermal neutron detectors. The basic device structure of the MSND involves micro-sized trenches that are etched into a vertically-oriented pvn-junction diode that are backfilled with a neutron converting material. Neutrons absorbed within the converting material induce fission of the parent nucleus, producing a pair of energetic charged-particle reaction products that can be counted by the diode. The MSND deep-etched microstructures produce good neutron-absorption and reaction-product counting efficiencies, offering a 10× improvement in intrinsic thermal neutron detection efficiency over thin-film-coated devices. Performance of present-day MSNDs are nearing theoretical limits; streaming paths between the conversion-material backfilled trenches, allow a considerable fraction of neutrons to pass undetected through the device. Dual-sided microstructured semiconductor neutron detectors (DSMSNDs) have been developed that utilize a complementary second set of trenches on the back-side of the device to count streaming neutrons. DSMSND devices are theoretically capable of greater than 80% intrinsic thermal neutron detection efficiency for a 1-mm thick device. The first such prototype DSMSNDs, presented here, have achieved 29.48±0.29% nearly 2× better than MSNDs with similar microstructure dimensions.

  11. Detector design issues for compact nuclear emission cameras dedicated to breast imaging

    International Nuclear Information System (INIS)

    Levin, Craig S.

    2003-01-01

    Certain gamma ray and positron emitting radiotracers have shown great promise for use in the detection, diagnosis and staging of breast cancer. Unfortunately, standard nuclear emission cameras (SPECT, PET) found in the clinic are not practical for breast imaging of these emissions due to inadequate spatial and energy resolutions and sensitivity, large and awkward size, and relatively high cost per study. High spatial and energy resolutions and sensitivity are needed for good lesion detectability. Due to these limitations of standard cameras, there has been recent research into the development of small, compact nuclear emission imagers dedicated for close-proximity breast imaging. The small detector head size means a variety of exotic detectors or collimators may be implemented to improve spatial and energy resolution and sensitivity performances at a reasonable cost. In this paper, we will present some of the compact gamma ray and annihilation photon imaging detector designs that have been proposed and/or developed for dedicated breast imaging. We will review the physics and discuss the advantages and disadvantages of various detector configurations. Finally we will estimate the fundamental spatial resolution potential available with close-proximity nuclear emission imaging and discuss how one may approach those limits through proper detector design

  12. Design and performance of an acquisition and control system for a positron camera with novel detectors

    International Nuclear Information System (INIS)

    Symonds-Tayler, J.R.N.; Reader, A.J.; Flower, M.A.

    1996-01-01

    A Sun-based data acquisition and control (DAQ) system has been designed for PETRRA, a whole-body positron camera using large-area BaF 2 -TMAE detectors. The DAQ system uses a high-speed digital I/O card (S16D) installed on the S-bus of a SPARC10 and a specially-designed Positron Camera Interface (PCI), which also controls both the gantry and horizontal couch motion. Data in the form of different types of 6-byte packets are acquired in list mode. Tests with a signal generator show that the DAQ system should be able to cater for coincidence count-rates up to 100 kcps. The predicted count loss due to the DAQ system is ∼13% at this count rate, provided asynchronous-read based software is used. The list-mode data acquisition system designed for PETRRA could be adapted for other 3D PET cameras with similar data rates

  13. A pixellated γ-camera based on CdTe detectors clinical interests and performances

    International Nuclear Information System (INIS)

    Chambron, J.; Arntz, Y.; Eclancher, B.; Scheiber, Ch.; Siffert, P.; Hage Hali, M.; Regal, R.; Kazandjian, A.; Prat, V.; Thomas, S.; Warren, S.; Matz, R.; Jahnke, A.; Karman, M.; Pszota, A.; Nemeth, L.

    2000-01-01

    A mobile gamma camera dedicated to nuclear cardiology, based on a 15 cmx15 cm detection matrix of 2304 CdTe detector elements, 2.83 mmx2.83 mmx2 mm, has been developed with a European Community support to academic and industrial research centres. The intrinsic properties of the semiconductor crystals - low-ionisation energy, high-energy resolution, high attenuation coefficient - are potentially attractive to improve the γ-camera performances. But their use as γ detectors for medical imaging at high resolution requires production of high-grade materials and large quantities of sophisticated read-out electronics. The decision was taken to use CdTe rather than CdZnTe, because the manufacturer (Eurorad, France) has a large experience for producing high-grade materials, with a good homogeneity and stability and whose transport properties, characterised by the mobility-lifetime product, are at least 5 times greater than that of CdZnTe. The detector matrix is divided in 9 square units, each unit is composed of 256 detectors shared in 16 modules. Each module consists in a thin ceramic plate holding a line of 16 detectors, in four groups of four for an easy replacement, and holding a special 16 channels integrated circuit designed by CLRC (UK). A detection and acquisition logic based on a DSP card and a PC has been programmed by Eurorad for spectral and counting acquisition modes. Collimators LEAP and LEHR from commercial design, mobile gantry and clinical software were provided by Siemens (Germany). The γ-camera head housing, its general mounting and the electric connections were performed by Phase Laboratory (CNRS, France). The compactness of the γ-camera head, thin detectors matrix, electronic readout and collimator, facilitates the detection of close γ sources with the advantage of a high spatial resolution. Such an equipment is intended to bedside explorations. There is a growing clinical requirement in nuclear cardiology to early assess the extent of an infarct

  14. A data acquisition system for coincidence imaging using a conventional dual head gamma camera

    Science.gov (United States)

    Lewellen, T. K.; Miyaoka, R. S.; Jansen, F.; Kaplan, M. S.

    1997-06-01

    A low cost data acquisition system (DAS) was developed to acquire coincidence data from an unmodified General Electric Maxxus dual head scintillation camera. A high impedance pick-off circuit provides position and energy signals to the DAS without interfering with normal camera operation. The signals are pulse-clipped to reduce pileup effects. Coincidence is determined with fast timing signals derived from constant fraction discriminators. A charge-integrating FERA 16 channel ADC feeds position and energy data to two CAMAC FERA memories operated as ping-pong buffers. A Macintosh PowerPC running Labview controls the system and reads the CAMAC memories. A CAMAC 12-channel scaler records singles and coincidence rate data. The system dead-time is approximately 10% at a coincidence rate of 4.0 kHz.

  15. A data acquisition system for coincidence imaging using a conventional dual head gamma camera

    International Nuclear Information System (INIS)

    Lewellen, T.K.; Miyaoka, R.S.; Kaplan, M.S.

    1996-01-01

    A low cost data acquisition system (DAS) was developed to acquire coincidence data from an unmodified General Electric Maxxus dual head scintillation camera. A high impedance pick-off circuit provides position and energy signals to the DAS without interfering with normal camera operation. The signals are pulse-clipped to reduce pileup effects. Coincidence is determined with fast timing signals derived from constant fraction discriminators. A charge-integrating FERA 16 channel ADC feeds position and energy data to two CAMAC FERA memories operated as ping-pong buffers. A Macintosh PowerPC running Labview controls the system and reads the CAMAC memories. A CAMAC 12-channel scaler records singles and coincidence rate data. The system dead-time is approximately 10% at a coincidence rate of 4.0 kHz

  16. Simulation of a multi-detector gamma camera for validation protocols of quantification the activity from SPECT images

    International Nuclear Information System (INIS)

    Lozano Sanchez, A.; Calderon Marin, C.; Gonzalez Gonzalez, J.

    2015-01-01

    The main sources that decreasing accuracy in the estimation of internal absorbed dose has been identified in the methods for the quantification of cumulated activity from scintigraphic imaging, likes the corrections required by the physical and instrumental phenomena related to the formation of those images. The results of the simulation of a dual detector gamma camera E.cam SIEMENS using the Monte Carlo code SIMIND to obtain tomographic SPECT projections are presented here. SIMIND will allow dealing with the contribution of physical interactions and instrumental effects during simulations. Energy resolution, spatial resolution and sensitivity planar were determined with real and simulated systems. The relative differences did not exceed 10%. Energy spectra simulated under different conditions (source in air and water) with the inclusion of interactions in the collimator and phantom were compared. The tomographic sensitivity of a volumetric phantom containing radioactive solutions of 99m Tc and 131 I were determined from real and simulated SPECT images. Two processing protocols were considered: with scatter correction ( 99m Tc dual energy window method and 131 I were calculated after corrections. The results, expressed in terms of the differences relative to the well-know activity value in the phantom inserts improves when attenuation and scattering corrections are applied, obtaining good agreement between the results for real and simulated systems. (Author)

  17. Superiority of triple-detector single-photon emission tomography over single- and dual-detector systems in the minimization of motion artefacts

    International Nuclear Information System (INIS)

    Nakajima, Kenichi; Taki, Junichi; Michigishi, Takatoshi; Tonami, Norihisa

    1998-01-01

    A patient motion-related artefact is one of the most important artefacts in single-photon emission tomography (SPET) imaging. This study evaluated the effect of the number and configuration of SPET detectors on motion artefacts. The following acquisition conditions were simulated based on original 360 projection images: (1) single-detector 180 rotation (S180), (2) a dual-detector rectangular (L-shaped) 180 acquisition (D180L), (3) dual-detector cameras mounted opposite each other with 360 acquisition (D360) and (4) triple-detector 360 acquisition (T360). The motion artefacts were introduced using a syringe and a myocardial phantom. Clinical cases with technetium-99m methoxyisobutylisonitrile and thallium-201 studies were analysed to confirm the validity of this phantom simulation. The effect of continuous alternate rotation acquisition and summing the projections on the reduction of motion artefacts was investigated in each model. The effect of motion depended on the number and the configuration of the SPET detectors. A 1-pixel (6.4 mm) motion in the S180, D180L and D360 models generated only slight artefacts, and a 2-pixel motion led to an apparent decrease in activity or created hot areas in the myocardium. On the other hand, a T360 rotation created few artefacts even with a 2-pixel motion of the last quarter of the projections. Despite the difference in attenuation with 201 Tl and 99m Tc, similar artefact patterns were observed with both radionuclides in selected patient model studies. Continuous alternate rotation could reduce artefacts caused by less than a 2-pixel motion. In conclusion, calculating the average of the sum of the projections of triple-detector 360 rotations with alternate rotation is the best method to minimize motion artefacts. This ''averaging'' effect of motion artefacts is a key to this simulation. (orig.)

  18. A new CCD-camera neutron radiography detector at the Atominstitute of the Austrian Universities

    International Nuclear Information System (INIS)

    Koerner, S.; Boeck, H.; Rauch, H.; Lehmann, E.

    1999-01-01

    Neutron radiography provides a very efficient tool for non-destructive testing as well as for many applications in fundamental research. A neutron beam penetrating a specimen is attenuated by the sample material and detected by a two dimensional imaging device. The image contains information about materials and structure inside the sample because neutrons are attenuated according to the basic law of radiation attenuation. At the Atominstitute of the Austrian Universities neutron radiographic examinations have been carried out for more than 35 years, mainly with detectors consisting of X-ray films and a Gd- converter enclosed in a vacuum cassette. Presently a neutron tomography set-up is under development. For high quality 3D image reconstruction, about 200 digitized neutron transmission images from different angles of the object are necessary. Therefore the first step was the design of an adequate electronic neutron radiography imaging device. The requirements for a detector suitable for neutron tomography are: exact and reproducible positioning, easy handling, high spatial resolution and dynamic range, high efficiency and a good linearity. The key components of the detector system selected on the basis of the requirements consist of a neutron sensitive scintillator screen, a cooled slow scan CCD camera and a mirror to reflect the light emitted by the scintillator to the CCD camera. The whole assembly is placed in a light tight enclosure. In this paper the strategy of the selection of the individual detector components is described. Comparisons on the influence of the use of different components on the properties of the whole position sensitive imaging device are demonstrated. Finally the new CCD camera neutron radiography detector of the Atominstitute is presented and first results of test measurements performed at the neutron radiography facility NEUTRA at the continuous spallation source SINQ at Paul Scherrer Institute are shown.(author)

  19. Application of colon capsule endoscopy (CCE to evaluate the whole gastrointestinal tract: a comparative study of single-camera and dual-camera analysis

    Directory of Open Access Journals (Sweden)

    Remes-Troche JM

    2013-09-01

    Full Text Available José María Remes-Troche,1 Victoria Alejandra Jiménez-García,2 Josefa María García-Montes,2 Pedro Hergueta-Delgado,2 Federico Roesch-Dietlen,1 Juan Manuel Herrerías-Gutiérrez2 1Digestive Physiology and Motility Lab, Medical Biological Research Institute, Universidad Veracruzana, Veracruz, México; 2Gastroenterology Service, Virgen Macarena University Hospital, Seville, Spain Background and study aims: Colon capsule endoscopy (CCE was developed for the evaluation of colorectal pathology. In this study, our aim was to assess if a dual-camera analysis using CCE allows better evaluation of the whole gastrointestinal (GI tract compared to a single-camera analysis. Patients and methods: We included 21 patients (12 males, mean age 56.20 years submitted for a CCE examination. After standard colon preparation, the colon capsule endoscope (PillCam Colon™ was swallowed after reinitiation from its “sleep” mode. Four physicians performed the analysis: two reviewed both video streams at the same time (dual-camera analysis; one analyzed images from one side of the device (“camera 1”; and the other reviewed the opposite side (“camera 2”. We compared numbers of findings from different parts of the entire GI tract and level of agreement among reviewers. Results: A complete evaluation of the GI tract was possible in all patients. Dual-camera analysis provided 16% and 5% more findings compared to camera 1 and camera 2 analysis, respectively. Overall agreement was 62.7% (kappa = 0.44, 95% CI: 0.373–0.510. Esophageal (kappa = 0.611 and colorectal (kappa = 0.595 findings had a good level of agreement, while small bowel (kappa = 0.405 showed moderate agreement. Conclusion: The use of dual-camera analysis with CCE for the evaluation of the GI tract is feasible and detects more abnormalities when compared with single-camera analysis. Keywords: capsule endoscopy, colon, gastrointestinal tract, small bowel

  20. Development of an ultra-fast X-ray camera using hybrid pixel detectors

    International Nuclear Information System (INIS)

    Dawiec, A.

    2011-05-01

    The aim of the project whose work described in this thesis is part, was to design a high-speed X-ray camera using hybrid pixels applied to biomedical imaging and for material science. As a matter of fact the hybrid pixel technology meets the requirements of these two research fields, particularly by providing energy selection and low dose imaging capabilities. In this thesis, high frame rate X-ray imaging based on the XPAD3-S photons counting chip is presented. Within a collaboration between CPPM, ESRF and SOLEIL, three XPAD3 cameras were built. Two of them are being operated at the beamline of the ESRF and SOLEIL synchrotron facilities and the third one is embedded in the PIXSCAN II irradiation setup of CPPM. The XPAD3 camera is a large surface X-ray detector composed of eight detection modules of seven XPAD3-S chips each with a high-speed data acquisition system. The readout architecture of the camera is based on the PCI Express interface and on programmable FPGA chips. The camera achieves a readout speed of 240 images/s, with maximum number of images limited by the RAM memory of the acquisition PC. The performance of the device was characterized by carrying out several high speed imaging experiments using the PIXSCAN II irradiation setup described in the last chapter of this thesis. (author)

  1. The use of a Micromegas as a detector for gamma camera

    International Nuclear Information System (INIS)

    Barbouchi, Asma; Trabelsi, Adel

    2008-01-01

    The micromegas (Micro Mesh Gaseaous) is a gas detector; it was developed by I.Giomattaris and G.Charpak for application in the field of experimental particle physics. But the polyvalence of this detector makes it to be used in several areas such as medical imaging. This detector has an X-Y readout capability of resolution less than 100μm, an energy resolution down to 14% for energy range 1-10 keV and an overall efficiency of 70%. Monte carlo simulation is widely used in nuclear medicine. It allows predicting the behaviour of system. Gate (Geant4 for Application Tomography Emission) is a platform for monte carlo simulation. It is dedicated to PET/SPECT (Position Emission Tomography / single Photon Emission Tomography) applications. Our goal is to model a gamma camera that use a Micromegas as a detector and to compare their performances (energy resolution, point spread function...) with those of a scintillated gamma camera by using Gate

  2. The iQID camera: An ionizing-radiation quantum imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Brian W., E-mail: brian.miller@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); College of Optical Sciences, The University of Arizona, Tucson, AZ 85719 (United States); Gregory, Stephanie J.; Fuller, Erin S. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Barrett, Harrison H.; Bradford Barber, H.; Furenlid, Lars R. [Center for Gamma-Ray Imaging, The University of Arizona, Tucson, AZ 85719 (United States); College of Optical Sciences, The University of Arizona, Tucson, AZ 85719 (United States)

    2014-12-11

    We have developed and tested a novel, ionizing-radiation Quantum Imaging Detector (iQID). This scintillation-based detector was originally developed as a high-resolution gamma-ray imager, called BazookaSPECT, for use in single-photon emission computed tomography (SPECT). Recently, we have investigated the detector's response and imaging potential with other forms of ionizing radiation including alpha, neutron, beta, and fission fragment particles. The confirmed response to this broad range of ionizing radiation has prompted its new title. The principle operation of the iQID camera involves coupling a scintillator to an image intensifier. The scintillation light generated by particle interactions is optically amplified by the intensifier and then re-imaged onto a CCD/CMOS camera sensor. The intensifier provides sufficient optical gain that practically any CCD/CMOS camera can be used to image ionizing radiation. The spatial location and energy of individual particles are estimated on an event-by-event basis in real time using image analysis algorithms on high-performance graphics processing hardware. Distinguishing features of the iQID camera include portability, large active areas, excellent detection efficiency for charged particles, and high spatial resolution (tens of microns). Although modest, iQID has energy resolution that is sufficient to discriminate between particles. Additionally, spatial features of individual events can be used for particle discrimination. An important iQID imaging application that has recently been developed is real-time, single-particle digital autoradiography. We present the latest results and discuss potential applications.

  3. Initial experience with a prototype dual-crystal (LSO/NaI) dual-head coincidence camera in oncology

    International Nuclear Information System (INIS)

    Joshi, Urvi; Boellaard, Ronald; Comans, Emile F.I.; Raijmakers, Pieter G.H.M.; Pijpers, Rik J.; Teule, Gerrit J.J.; Lingen, Arthur van; Hoekstra, Otto S.; Miller, Steven D.

    2004-01-01

    The aim of this study was to evaluate the in vivo performance of a prototype dual-crystal [lutetium oxyorthosilicate (LSO)/sodium iodide (NaI)] dual-head coincidence camera (DHC) for PET and SPET (LSO-PS), in comparison to BGO-PET with fluorine-18 fluorodeoxyglucose (FDG) in oncology. This follows earlier reports that LSO-PS has noise-equivalent counting (NEC) rates comparable to partial ring BGO-PET, i.e. clearly higher than standard NaI DHCs. Twenty-four randomly selected oncological patients referred for whole-body FDG-PET underwent BGO-PET followed by LSO-PS. Four nuclear medicine physicians were randomised to read a single scan modality, in terms of lesion intensity, location and likelihood of malignancy. BGO-PET was considered the gold standard. Forty-eight lesions were classified as positive with BGO-PET, of which LSO-PS identified 73% (95% CI 60-86%). There was good observer agreement for both modalities in terms of intensity, location and interpretation. Lesions were missed by LSO-PS in 13 patients in the chest (n=6), neck (n=3) and abdomen (n=4). The diameter of these lesions was estimated to be 0.5-1 cm. Initial results justify further evaluation of LSO-PS in specific clinical situations, especially if a role as an instrument of triage for PET is foreseen. (orig.)

  4. Optimizing detector thickness in dual-shot dual-energy x-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Woon; Kam, Soohwa; Youn, Hanbean; Kim, Ho Kyung [Pusan National University, Busan (Korea, Republic of)

    2015-05-15

    As a result, there exist apparent limitations in the conventional two-dimensional (2D) radiography: One is that the contrast between the structure of interest and the background in a radiograph is much less than the intrinsic subject contrast (i.e. the difference between their attenuation coefficients; Another is that the superimposed anatomical structures in the 2D radiograph results in an anatomical background clutter that may decrease the conspicuity of subtle underlying features. These limitations in spatial and material discrimination are important motivations for the recent development of 3D (e.g. tomosynthesis) and dual energy imaging (DEI) systems. DEI technique uses a combination of two images obtained at two different energies in successive x-ray exposures by rapidly switching the kilovolage (kV) applied to the x-ray tube. Commercial DEI systems usually employ a 'single' of flat-panel detector (FPD) to obtain two different kV images. However, we have a doubt in the use of the same detector for acquiring two different projections for the low- and high-kV setups because it is typically known that there exists an optimal detector thickness regarding specific imaging tasks or energies used.

  5. A pixellated gamma-camera based on CdTe detectors clinical interests and performances

    CERN Document Server

    Chambron, J; Eclancher, B; Scheiber, C; Siffert, P; Hage-Ali, M; Regal, R; Kazandjian, A; Prat, V; Thomas, S; Warren, S; Matz, R; Jahnke, A; Karman, M; Pszota, A; Németh, L

    2000-01-01

    A mobile gamma camera dedicated to nuclear cardiology, based on a 15 cmx15 cm detection matrix of 2304 CdTe detector elements, 2.83 mmx2.83 mmx2 mm, has been developed with a European Community support to academic and industrial research centres. The intrinsic properties of the semiconductor crystals - low-ionisation energy, high-energy resolution, high attenuation coefficient - are potentially attractive to improve the gamma-camera performances. But their use as gamma detectors for medical imaging at high resolution requires production of high-grade materials and large quantities of sophisticated read-out electronics. The decision was taken to use CdTe rather than CdZnTe, because the manufacturer (Eurorad, France) has a large experience for producing high-grade materials, with a good homogeneity and stability and whose transport properties, characterised by the mobility-lifetime product, are at least 5 times greater than that of CdZnTe. The detector matrix is divided in 9 square units, each unit is composed ...

  6. A passive terahertz video camera based on lumped element kinetic inductance detectors

    International Nuclear Information System (INIS)

    Rowe, Sam; Pascale, Enzo; Doyle, Simon; Dunscombe, Chris; Hargrave, Peter; Papageorgio, Andreas; Ade, Peter A. R.; Barry, Peter; Bideaud, Aurélien; Brien, Tom; Dodd, Chris; House, Julian; Moseley, Paul; Sudiwala, Rashmi; Tucker, Carole; Walker, Ian; Wood, Ken; Grainger, William; Mauskopf, Philip; Spencer, Locke

    2016-01-01

    We have developed a passive 350 GHz (850 μm) video-camera to demonstrate lumped element kinetic inductance detectors (LEKIDs)—designed originally for far-infrared astronomy—as an option for general purpose terrestrial terahertz imaging applications. The camera currently operates at a quasi-video frame rate of 2 Hz with a noise equivalent temperature difference per frame of ∼0.1 K, which is close to the background limit. The 152 element superconducting LEKID array is fabricated from a simple 40 nm aluminum film on a silicon dielectric substrate and is read out through a single microwave feedline with a cryogenic low noise amplifier and room temperature frequency domain multiplexing electronics.

  7. A passive terahertz video camera based on lumped element kinetic inductance detectors

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, Sam, E-mail: sam.rowe@astro.cf.ac.uk; Pascale, Enzo; Doyle, Simon; Dunscombe, Chris; Hargrave, Peter; Papageorgio, Andreas; Ade, Peter A. R.; Barry, Peter; Bideaud, Aurélien; Brien, Tom; Dodd, Chris; House, Julian; Moseley, Paul; Sudiwala, Rashmi; Tucker, Carole; Walker, Ian [Astronomy Instrumentation Group, School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Wood, Ken [QMC Instruments Ltd., School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Grainger, William [Rutherford Appleton Laboratory, STFC, Swindon SN2 1SZ (United Kingdom); Mauskopf, Philip [Astronomy Instrumentation Group, School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); School of Earth Science and Space Exploration, Arizona State University, Tempe, Arizona 85281 (United States); Spencer, Locke [Department of Physics and Astronomy, University of Lethbridge, Lethbridge, Alberta T1K 3M4 (Canada)

    2016-03-15

    We have developed a passive 350 GHz (850 μm) video-camera to demonstrate lumped element kinetic inductance detectors (LEKIDs)—designed originally for far-infrared astronomy—as an option for general purpose terrestrial terahertz imaging applications. The camera currently operates at a quasi-video frame rate of 2 Hz with a noise equivalent temperature difference per frame of ∼0.1 K, which is close to the background limit. The 152 element superconducting LEKID array is fabricated from a simple 40 nm aluminum film on a silicon dielectric substrate and is read out through a single microwave feedline with a cryogenic low noise amplifier and room temperature frequency domain multiplexing electronics.

  8. Testing and assembly of the detectors for the Millimeter Bolometer Array Camera on ACT

    International Nuclear Information System (INIS)

    Marriage, T.A.; Chervenak, J.A.; Doriese, W.B.

    2006-01-01

    The Millimeter Bolometer Array Camera (MBAC) for the Atacama Cosmology Telescope consists of three Transition Edge Sensor (TES) arrays to make simultaneous observations of the Cosmic Microwave Background in three frequency bands. MBAC TESs are NASA Goddard Pop-Up Detectors (PUD) which are read-out by NIST time-domain multiplexers. MBAC is constructed by stacking 1x32 TES columns to form the 32x32 element arrays. The arrays are modular (connectorized) at the 1x32 column level such that array assembly is reversible and camera repair possible. Prior to assembly, each column is tested in a quick (2h) cycling 4 He/ 3 He adsorption refrigerator. Tests include measurements of TES current-voltage curves and TES complex impedance

  9. Testing and assembly of the detectors for the Millimeter Bolometer Array Camera on ACT

    Energy Technology Data Exchange (ETDEWEB)

    Marriage, T.A. [Physics Department, Princeton University, Washington Road, Princeton, NJ 08544 (United States)]. E-mail: marriage@princeton.edu; Chervenak, J.A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Doriese, W.B. [National Institute of Standards, 325 Broadway, Boulder, CO 80305 (United States)

    2006-04-15

    The Millimeter Bolometer Array Camera (MBAC) for the Atacama Cosmology Telescope consists of three Transition Edge Sensor (TES) arrays to make simultaneous observations of the Cosmic Microwave Background in three frequency bands. MBAC TESs are NASA Goddard Pop-Up Detectors (PUD) which are read-out by NIST time-domain multiplexers. MBAC is constructed by stacking 1x32 TES columns to form the 32x32 element arrays. The arrays are modular (connectorized) at the 1x32 column level such that array assembly is reversible and camera repair possible. Prior to assembly, each column is tested in a quick (2h) cycling {sup 4}He/{sup 3}He adsorption refrigerator. Tests include measurements of TES current-voltage curves and TES complex impedance.

  10. Easy method to measure radioactive waste with a gamma-camera detector

    International Nuclear Information System (INIS)

    Murat, C.; Barrau, C.

    2007-01-01

    The aim of this technical note is to evaluate an easy method to measure 99m Tc samples with an activity of 1000, 100 and 10 Bq/L. This study is performed with a gamma camera detector in two departments of nuclear medicine in Avignon and in Nimes. We develop a procedure to measure 99m Tc radioactive waste at the two hospitals output in accordance with the D.G.S./D.H.O.S. no. 2001/323 circular requests of the Ministry for Employment and Solidarity. (authors)

  11. Fiber scintillator/streak camera detector for burn history measurement in inertial confinement fusion experiment

    International Nuclear Information System (INIS)

    Miyanaga, N.; Ohba, N.; Fujimoto, K.

    1997-01-01

    To measure the burn history in an inertial confinement fusion experiment, we have developed a new neutron detector based on plastic scintillation fibers. Twenty-five fiber scintillators were arranged in a geometry compensation configuration by which the time-of-flight difference of the neutrons is compensated by the transit time difference of light passing through the fibers. Each fiber scintillator is spliced individually to an ultraviolet optical fiber that is coupled to a streak camera. We have demonstrated a significant improvement of sensitivity compared with the usual bulk scintillator coupled to a bundle of the same ultraviolet fibers. copyright 1997 American Institute of Physics

  12. Implementation of an image acquisition and processing system based on FlexRIO, CameraLink and areaDetector

    Energy Technology Data Exchange (ETDEWEB)

    Esquembri, S.; Ruiz, M. [Instrumentation and Applied Acoustic Research Group, Technical University of Madrid (UPM), Madrid (Spain); Barrera, E., E-mail: eduardo.barrera@upm.es [Instrumentation and Applied Acoustic Research Group, Technical University of Madrid (UPM), Madrid (Spain); Sanz, D.; Bustos, A. [Instrumentation and Applied Acoustic Research Group, Technical University of Madrid (UPM), Madrid (Spain); Castro, R.; Vega, J. [National Fusion Laboratory, CIEMAT, Madrid (Spain)

    2016-11-15

    Highlights: • The system presented acquires and process images from any CameraLink compliant camera. • The frame grabber implanted with FlexRIO technology have image time stamping and preprocessing capabilities. • The system is integrated into EPICS using areaDetector for a flexible configuration of image the acquisition and processing chain. • Is fully compatible with the architecture of the ITER Fast Controllers. - Abstract: Image processing systems are commonly used in current physics experiments, such as nuclear fusion experiments. These experiments usually require multiple cameras with different resolutions, framerates and, frequently, different software drivers. The integration of heterogeneous types of cameras without a unified hardware and software interface increases the complexity of the acquisition system. This paper presents the implementation of a distributed image acquisition and processing system for CameraLink cameras. This system implements a camera frame grabber using Field Programmable Gate Arrays (FPGAs), a reconfigurable hardware platform that allows for image acquisition and real-time preprocessing. The frame grabber is integrated into Experimental Physics and Industrial Control System (EPICS) using the areaDetector EPICS software module, which offers a common interface shared among tens of cameras to configure the image acquisition and process these images in a distributed control system. The use of areaDetector also allows the image processing to be parallelized and concatenated using: multiple computers; areaDetector plugins; and the areaDetector standard type for data, NDArrays. The architecture developed is fully compatible with ITER Fast Controllers and the entire system has been validated using a camera hardware simulator that stream videos from fusion experiment databases.

  13. Two New Types of Detector for X- or Gamma-Ray Cameras

    International Nuclear Information System (INIS)

    Kellershohn, C.; Desgrez, A.; Lansiart, A.

    1964-01-01

    X- or γ-ray cameras consist essentially of a hole-type or grid-type lens system together with a detector. The authors propose two kinds of detector quite different from the Anger device, which so far has been the only one in practical use. The first consists of a self-triggering spark chamber. This chamber, about 20 cm in diam. and filled with a rare gas (argon or xenon), forms a cathode and two grids. The cathode and the second grid are subjected to a potential difference of several kilovolts, somewhat lower than the breakdown voltage. The first cathode-grid space serves as an electron source under the action of the low-energy X- or γ-ray photons. The cathode can also be plated with a metal of high Z, or a crystal scintillator connected to a photocathode can be used. After suitable amplification, the sudden burst of charges due to electron multiplication in the Townsend avalanche produces a well localized spark with a delay of a fraction of a microsecond. The image is obtained with the aid of a camera whose shutter is permanently open. The second type of detector consists of a Csl (Tl) crystal connected to the photocathode of a Thomson tube, 20 cm in diam. and with electrostatic focusing. The image on the secondary screen of this tube is transferred by an optical device to the photocathode of a tube with parallel electric and magnetic field (manufactured by the English Electric Valve Company) and serving as shutter. Some of the light entering the optical device is received by a photomultiplier, which controls the opening of the shutter tube through an amplitude selector. This arrangement makes it possible to distinguish between the light due to the signal and that due to the noise of the Thomson tube. The shutter tube is opened only by the former. Since the shutter tube remains open for only an extremely short time, the signal-noise ratio of this detector arrangement is high enough to give an image on the end screen of the shutter tube using a permanently open

  14. Segmentation algorithm on smartphone dual camera: application to plant organs in the wild

    Science.gov (United States)

    Bertrand, Sarah; Cerutti, Guillaume; Tougne, Laure

    2018-04-01

    In order to identify the species of a tree, the different organs that are the leaves, the bark, the flowers and the fruits, are inspected by botanists. So as to develop an algorithm that identifies automatically the species, we need to extract these objects of interest from their complex natural environment. In this article, we focus on the segmentation of flowers and fruits and we present a new method of segmentation based on an active contour algorithm using two probability maps. The first map is constructed via the dual camera that we can find on the back of the latest smartphones. The second map is made with the help of a multilayer perceptron (MLP). The combination of these two maps to drive the evolution of the object contour allows an efficient segmentation of the organ from a natural background.

  15. Design and implementation of a dual-wavelength intrinsic fluorescence camera system

    Science.gov (United States)

    Ortega-Martinez, Antonio; Musacchia, Joseph J.; Gutierrez-Herrera, Enoch; Wang, Ying; Franco, Walfre

    2017-03-01

    Intrinsic UV fluorescence imaging is a technique that permits the observation of spatial differences in emitted fluorescence. It relies on the fluorescence produced by the innate fluorophores in the sample, and thus can be used for marker-less in-vivo assessment of tissue. It has been studied as a tool for the study of the skin, specifically for the classification of lesions, the delimitation of lesion borders and the study of wound healing, among others. In its most basic setup, a sample is excited with a narrow-band UV light source and the resulting fluorescence is imaged with a UV sensitive camera filtered to the emission wavelength of interest. By carefully selecting the excitation/emission pair, we can observe changes in fluorescence associated with physiological processes. One of the main drawbacks of this simple setup is the inability to observe more than a single excitation/emission pair at the same time, as some phenomena are better studied when two or more different pairs are studied simultaneously. In this work, we describe the design and the hardware and software implementation of a dual wavelength portable UV fluorescence imaging system. Its main components are an UV camera, a dual wavelength UV LED illuminator (295 and 345 nm) and two different emission filters (345 and 390 nm) that can be swapped by a mechanical filter wheel. The system is operated using a laptop computer and custom software that performs basic pre-processing to improve the image. The system was designed to allow us to image fluorescent peaks of tryptophan and collagen cross links in order to study wound healing progression.

  16. Development Of A Multicolor Sub/millimeter Camera Using Microwave Kinetic Inductance Detectors

    Science.gov (United States)

    Schlaerth, James A.; Czakon, N. G.; Day, P. K.; Downes, T. P.; Duan, R.; Glenn, J.; Golwala, S. R.; Hollister, M. I.; LeDuc, H. G.; Maloney, P. R.; Mazin, B. A.; Noroozian, O.; Sayers, J.; Siegel, S.; Vayonakis, A.; Zmuidzinas, J.

    2011-01-01

    Microwave Kinetic Inductance Detectors (MKIDs) are superconducting resonators useful for detecting light from the millimeter-wave to the X-ray. These detectors are easily multiplexed, as the resonances can be tuned to slightly different frequencies, allowing hundreds of detectors to be read out simultaneously using a single feedline. The Multicolor Submillimeter Inductance Camera, MUSIC, will use 2304 antenna-coupled MKIDs in multicolor operation, with bands centered at wavelengths of 0.85, 1.1, 1.3 and 2.0 mm, beginning in 2011. Here we present the results of our demonstration instrument, DemoCam, containing a single 3-color array with 72 detectors and optics similar to MUSIC. We present sensitivities achieved at the telescope, and compare to those expected based upon laboratory tests. We explore the factors that limit the sensitivity, in particular electronics noise, antenna efficiency, and excess loading. We discuss mitigation of these factors, and how we plan to improve sensitivity to the level of background-limited performance for the scientific operation of MUSIC. Finally, we note the expected mapping speed and contributions of MUSIC to astrophysics, and in particular to the study of submillimeter galaxies. This research has been funded by grants from the National Science Foundation, the Gordon and Betty Moore Foundation, and the NASA Graduate Student Researchers Program.

  17. F-18 FDG PET with coincidence detection, dual-head gamma camera, initial experience in oncology

    Energy Technology Data Exchange (ETDEWEB)

    Chu, J.M.G.; Pocock, N.; Quach, T.; Camden, B.M.C. [Liverpool Health Services, Liverpool, NSW (Australia). Department of Nuclear Medicine and Clinical Ultrasound

    1998-06-01

    Full text: The development of Co-incidence Detection (CD) in gamma camera technology has allowed the use of positron radiopharmaceuticals in clinical practice without dedicated PET facilities. We report our initial experience of this technology in Oncological applications. All patients were administered 200 MBq of F- 18 FDG intravenously in a fasting state, with serum glucose below 8.9 mmol/L., and hydration well maintained. Tomography was performed using an ADAC Solus Molecular Co-incidence Detection (MCD) dual-head gamma camera, 60 minutes after administration and immediately after voiding. Tomography of the torso required up to three collections depending on the length of the patient, with each collection requiring 32 steps of 40 second duration, and a 50% overlap. Tomography of the brain required a single collection with 32 steps of 80 seconds. Patients were scanned in the supine position. An iterative reconstruction algorithm was employed without attenuation correction. All patients had histologically confirmed malignancy. Scan findings were correlated with results of all conventional diagnostic imaging procedures that were pertinent to the evaluation and management of each individual patient`s disease. Correlation with tumour type and treatment status was also undertaken. F-18 FDG uptake as demonstrated by CD-PET was increased in tumour bearing sites. The degree of increased uptake varied with tumour type and with treatment status. Our initial experience with CD-PET has been very encouraging, and has led us to undertake prospective short and long term studies to define its role in oncology

  18. A design of a high speed dual spectrometer by single line scan camera

    Science.gov (United States)

    Palawong, Kunakorn; Meemon, Panomsak

    2018-03-01

    A spectrometer that can capture two orthogonal polarization components of s light beam is demanded for polarization sensitive imaging system. Here, we describe the design and implementation of a high speed spectrometer for simultaneous capturing of two orthogonal polarization components, i.e. vertical and horizontal components, of light beam. The design consists of a polarization beam splitter, two polarization-maintain optical fibers, two collimators, a single line-scan camera, a focusing lens, and a reflection blaze grating. The alignment of two beam paths was designed to be symmetrically incident on the blaze side and reverse blaze side of reflection grating, respectively. The two diffracted beams were passed through the same focusing lens and focused on the single line-scan sensors of a CMOS camera. The two spectra of orthogonal polarization were imaged on 1000 pixels per spectrum. With the proposed setup, the amplitude and shape of the two detected spectra can be controlled by rotating the collimators. The technique for optical alignment of spectrometer will be presented and discussed. The two orthogonal polarization spectra can be simultaneously captured at a speed of 70,000 spectra per second. The high speed dual spectrometer can simultaneously detected two orthogonal polarizations, which is an important component for the development of polarization-sensitive optical coherence tomography. The performance of the spectrometer have been measured and analyzed.

  19. Quantification of atmospheric visibility with dual digital cameras during daytime and nighttime

    Directory of Open Access Journals (Sweden)

    K. Du

    2013-08-01

    Full Text Available A digital optical method "DOM-Vis" was developed to measure atmospheric visibility. In this method, two digital pictures were taken of the same target at two different distances along the same straight line. The pictures were analyzed to determine the optical contrasts between the target and its sky background and, subsequently, visibility is calculated. A light transfer scheme for DOM-Vis was delineated, based upon which algorithms were developed for both daytime and nighttime scenarios. A series of field tests were carried out under different weather and meteorological conditions to study the impacts of such operational parameters as exposure, optical zoom, distance between the two camera locations, and distance of the target. This method was validated by comparing the DOM-Vis results with those measured using a co-located Vaisala® visibility meter. The visibility under which this study was carried out ranged from 1 to 20 km. This digital-photography-based method possesses a number of advantages compared with traditional methods. Pre-calibration of the detector with a visibility meter is not required. In addition, the application of DOM-Vis is independent of several factors like the exact distance of the target and several camera setting parameters. These features make DOM-Vis more adaptive under a variety of field conditions.

  20. A DUAL-BAND MILLIMETER-WAVE KINETIC INDUCTANCE CAMERA FOR THE IRAM 30 m TELESCOPE

    International Nuclear Information System (INIS)

    Monfardini, A.; Benoit, A.; Bideaud, A.; Swenson, L.; Cruciani, A.; Camus, P.; Hoffmann, C.; Desert, F. X.; Doyle, S.; Ade, P.; Mauskopf, P.; Tucker, C.; Roesch, M.; Leclercq, S.; Schuster, K. F.; Endo, A.; Baryshev, A.; Baselmans, J. J. A.; Ferrari, L.; Yates, S. J. C

    2011-01-01

    The Neel IRAM KIDs Array (NIKA) is a fully integrated measurement system based on kinetic inductance detectors (KIDs) currently being developed for millimeter wave astronomy. The instrument includes dual-band optics allowing simultaneous imaging at 150 GHz and 220 GHz. The imaging sensors consist of two spatially separated arrays of KIDs. The first array, mounted on the 150 GHz branch, is composed of 144 lumped-element KIDs. The second array (220 GHz) consists of 256 antenna-coupled KIDs. Each of the arrays is sensitive to a single polarization; the band splitting is achieved by using a grid polarizer. The optics and sensors are mounted in a custom dilution cryostat, with an operating temperature of ∼70 mK. Electronic readout is realized using frequency multiplexing and a transmission line geometry consisting of a coaxial cable connected in series with the sensor array and a low-noise 4 K amplifier. The dual-band NIKA was successfully tested in 2010 October at the Institute for Millimetric Radio Astronomy (IRAM) 30 m telescope at Pico Veleta, Spain, performing in-line with laboratory predictions. An optical NEP was then calculated to be around 2 x 10 -16 W Hz -1/2 (at 1 Hz) while under a background loading of approximately 4 pW pixel -1 . This improvement in comparison with a preliminary run (2009) verifies that NIKA is approaching the target sensitivity for photon-noise limited ground-based detectors. Taking advantage of the larger arrays and increased sensitivity, a number of scientifically relevant faint and extended objects were then imaged including the Galactic Center SgrB2 (FIR1), the radio galaxy Cygnus A, and the NGC1068 Seyfert galaxy. These targets were all observed simultaneously in the 150 GHz and 220 GHz atmospheric windows.

  1. Three-layer GSO depth-of-interaction detector for high-energy gamma camera

    International Nuclear Information System (INIS)

    Yamamoto, S.; Watabe, H.; Kawachi, N.; Fujimaki, S.; Kato, K.; Hatazawa, J.

    2014-01-01

    Using Ce-doped Gd 2 SiO 5 (GSO) of different Ce concentrations, three-layer DOI block detectors were developed to reduce the parallax error at the edges of a pinhole gamma camera for high-energy gamma photons. GSOs with Ce concentrations of 1.5 mol% (decay time ∼40 ns), 0.5 mol% crystal (∼60 ns), 0.4 mol% (∼80 ns) were selected for the depth of interaction (DOI) detectors. These three types of GSOs were optically coupled in the depth direction, arranged in a 22×22 matrix and coupled to a flat panel photomultiplier tube (FP-PMT, Hamamatsu H8500). Sizes of these GSO cells were 1.9 mm×1.9 mm×4 mm, 1.9 mm×1.9 mm×5 mm, and 1.9 mm×1.9 mm×6 mm for 1.5 mol%, 0.5 mol%, and 0.4 mol%, respectively. With these combinations of GSOs, all spots corresponding to GSO cells were clearly resolved in the position histogram. Pulse shape spectra showed three peaks for these three decay times of GSOs. The block detector was contained in a 2-cm-thick tungsten shield, and a pinhole collimator with a 0.5-mm aperture was mounted. With pulse shape discrimination, we separated the point source images of the Cs-137 for each DOI layer. The point source image of the lower layer was detected at the most central part of the field-of-view, and the distribution was the smallest. The point source image of the higher layer was detected at the most peripheral part of the field-of-view, and the distribution was widest. With this information, the spatial resolution of the pinhole gamma camera can be improved. We conclude that DOI detection is effective for pinhole gamma cameras for high energy gamma photons

  2. Photomultiplier tube artifacts on 67Ga-citrate imaging caused by loss of correction floods due to an off-peak status of one head of a dual-head γ-camera.

    Science.gov (United States)

    Glaser, Joseph E; Song, Na; Jaini, Sridivya; Lorenzo, Ruth; Love, Charito

    2012-12-01

    γ-cameras use flood-field corrections to ensure image uniformity during clinical imaging. A loss or corruption of the correction data of one head of a dual-head camera can result in an off-peak artifactual appearance. We present our experience with the occurrence of such an incident on a (67)Ga scan. A patient was referred for a whole-body (67)Ga scan to evaluate for causes of neutropenic fever. Whole-body planar and static images of the head, chest, abdomen, pelvis, and lower extremities in multiple projections were obtained. Whole-body images showed decreased image quality on the anterior view obtained with detector 1 and an unremarkable posterior image obtained with detector 2. A problem with detector 2 was suspected, and additional static images were obtained after rotation of the detector heads. The posterior images taken with detector 1 showed photomultiplier tube outlines. The anterior images taken with detector 2 showed improved count and image quality. It was later found that the uniformity map for detector 2 had been lost and that this software malfunction led to the resulting imaging problem. When artifacts with an off-peak appearance are seen on scintigraphic images, evaluation of possible causes should include not only isotope window settings but also an incorrect or corrupted uniformity map.

  3. Optimal configuration of a low-dose breast-specific gamma camera based on semiconductor CdZnTe pixelated detectors

    Science.gov (United States)

    Genocchi, B.; Pickford Scienti, O.; Darambara, DG

    2017-05-01

    Breast cancer is one of the most frequent tumours in women. During the ‘90s, the introduction of screening programmes allowed the detection of cancer before the palpable stage, reducing its mortality up to 50%. About 50% of the women aged between 30 and 50 years present dense breast parenchyma. This percentage decreases to 30% for women between 50 to 80 years. In these women, mammography has a sensitivity of around 30%, and small tumours are covered by the dense parenchyma and missed in the mammogram. Interestingly, breast-specific gamma-cameras based on semiconductor CdZnTe detectors have shown to be of great interest to early diagnosis. Infact, due to the high energy, spatial resolution, and high sensitivity of CdZnTe, molecular breast imaging has been shown to have a sensitivity of about 90% independently of the breast parenchyma. The aim of this work is to determine the optimal combination of the detector pixel size, hole shape, and collimator material in a low dose dual head breast specific gamma camera based on a CdZnTe pixelated detector at 140 keV, in order to achieve high count rate, and the best possible image spatial resolution. The optimal combination has been studied by modeling the system using the Monte Carlo code GATE. Six different pixel sizes from 0.85 mm to 1.6 mm, two hole shapes, hexagonal and square, and two different collimator materials, lead and tungsten were considered. It was demonstrated that the camera achieved higher count rates, and better signal-to-noise ratio when equipped with square hole, and large pixels (> 1.3 mm). In these configurations, the spatial resolution was worse than using small pixel sizes (< 1.3 mm), but remained under 3.6 mm in all cases.

  4. Tests of a new CCD-camera based neutron radiography detector system at the reactor stations in Munich and Vienna

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E; Pleinert, H [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Schillinger, B [Technische Univ. Muenchen (Germany); Koerner, S [Atominstitut der Oesterreichischen Universitaeten, Vienna (Austria)

    1997-09-01

    The performance of the new neutron radiography detector designed at PSI with a cooled high sensitive CCD-camera was investigated under real neutronic conditions at three beam ports of two reactor stations. Different converter screens were applied for which the sensitivity and the modulation transfer function (MTF) could be obtained. The results are very encouraging concerning the utilization of this detector system as standard tool at the radiography stations at the spallation source SINQ. (author) 3 figs., 5 refs.

  5. Characterization of dual layer phoswich detector performance for small animal PET using Monte Carlo simulation

    International Nuclear Information System (INIS)

    Chung, Yong Hyun; Choi, Yong; Cho, Gyuseong; Choe, Yearn Seong; Lee, Kyung-Han; Kim, Byung-Tae

    2004-01-01

    A positron emission tomograph dedicated to small animal imaging should have high spatial resolution and sensitivity, and dual layer scintillators have been developed for this purpose. In this study, simulations were performed to optimize the order and the length of each crystal of a dual layer phoswich detector, and to evaluate the possibility of measuring signals from each layer of the phoswich detector. A simulation tool GATE was used to estimate the sensitivity and resolution of a small PET scanner. The proposed scanner is based on dual layer phoswich detector modules arranged in a ring of 10 cm diameter. Each module is composed of 8 x 8 arrays of phoswich detectors consisting of LSO and LuYAP with a 2 mm x 2 mm sensitive area coupled to a Hamamatsu R7600-00-M64 PSPMT. The length of the front layer of the phoswich detector varied from 0 to 10 mm at 1 mm intervals, and the total length (LSO + LuYAP) was fixed at 20 mm. The order of the crystal layers of the phoswich detector was also changed. Radial resolutions were kept below 3.4 mm and 3.7 mm over 8 cm FOV, and sensitivities were 7.4% and 8.0% for LSO 5 mm-LuYAP 15 mm, and LuYAP 6 mm-LSO 14 mm phoswich detectors, respectively. Whereas, high and uniform resolutions were achieved by using the LSO front layer, higher sensitivities were obtained by changing the crystal order. The feasibilities for applying crystal identification methods to phoswich detectors consisting of LSO and LuYAP were investigated using simulation and experimentally derived measurements of the light outputs from each layer of the phoswich detector. In this study, the optimal order and lengths of the dual layer phoswich detector were derived in order to achieve high sensitivity and high and uniform radial resolution

  6. Intraoperative implant rod three-dimensional geometry measured by dual camera system during scoliosis surgery.

    Science.gov (United States)

    Salmingo, Remel Alingalan; Tadano, Shigeru; Abe, Yuichiro; Ito, Manabu

    2016-05-12

    Treatment for severe scoliosis is usually attained when the scoliotic spine is deformed and fixed by implant rods. Investigation of the intraoperative changes of implant rod shape in three-dimensions is necessary to understand the biomechanics of scoliosis correction, establish consensus of the treatment, and achieve the optimal outcome. The objective of this study was to measure the intraoperative three-dimensional geometry and deformation of implant rod during scoliosis corrective surgery.A pair of images was obtained intraoperatively by the dual camera system before rotation and after rotation of rods during scoliosis surgery. The three-dimensional implant rod geometry before implantation was measured directly by the surgeon and after surgery using a CT scanner. The images of rods were reconstructed in three-dimensions using quintic polynomial functions. The implant rod deformation was evaluated using the angle between the two three-dimensional tangent vectors measured at the ends of the implant rod.The implant rods at the concave side were significantly deformed during surgery. The highest rod deformation was found after the rotation of rods. The implant curvature regained after the surgical treatment.Careful intraoperative rod maneuver is important to achieve a safe clinical outcome because the intraoperative forces could be higher than the postoperative forces. Continuous scoliosis correction was observed as indicated by the regain of the implant rod curvature after surgery.

  7. Noise performance of the multiwavelength sub/millimeter inductance camera (MUSIC) detectors

    International Nuclear Information System (INIS)

    Siegel, S. R.

    2015-01-01

    MUSIC is a multi-band imaging camera that employs 2304 Microwave Kinetic Inductance Detectors (MKIDs) in 576 spatial pixels to cover a 14 arc-minute field of view, with each pixel simultaneously sensitive to 4 bands centered at 0.87, 1.04, 1.33, and 1.98 mm. In April 2012 the MUSIC instrument was commissioned at the Caltech Submillimeter Observatory with a subset of the full focal plane. We examine the noise present in the detector timestreams during observations taken in the first year of operation. We find that fluctuations in atmospheric emission dominate at long timescales (< 0.5 Hz), and fluctuations in the amplitude and phase of the probe signal due to readout electronics contribute significant 1/f-type noise at shorter timescales. We describe a method to remove the amplitude, phase, and atmospheric noise using the fact that they are correlated among carrier tones. After removal, the complex signal is decomposed, or projected, into dissipation and frequency components. White noise from the cryogenic HEMT amplifier dominates in the dissipation component. An excess noise is observed in the frequency component that is likely due to fluctuations in two-level system (TLS) defects in the device substrate. We compare the amplitude of the TLS noise with previous measurements

  8. Noise performance of the multiwavelength sub/millimeter inductance camera (MUSIC) detectors

    Science.gov (United States)

    Siegel, S. R.

    2015-07-01

    MUSIC is a multi-band imaging camera that employs 2304 Microwave Kinetic Inductance Detectors (MKIDs) in 576 spatial pixels to cover a 14 arc-minute field of view, with each pixel simultaneously sensitive to 4 bands centered at 0.87, 1.04, 1.33, and 1.98 mm. In April 2012 the MUSIC instrument was commissioned at the Caltech Submillimeter Observatory with a subset of the full focal plane. We examine the noise present in the detector timestreams during observations taken in the first year of operation. We find that fluctuations in atmospheric emission dominate at long timescales (electronics contribute significant 1/f-type noise at shorter timescales. We describe a method to remove the amplitude, phase, and atmospheric noise using the fact that they are correlated among carrier tones. After removal, the complex signal is decomposed, or projected, into dissipation and frequency components. White noise from the cryogenic HEMT amplifier dominates in the dissipation component. An excess noise is observed in the frequency component that is likely due to fluctuations in two-level system (TLS) defects in the device substrate. We compare the amplitude of the TLS noise with previous measurements.

  9. A stacked CdTe pixel detector for a compton camera

    International Nuclear Information System (INIS)

    Oonuki, Kousuke; Tanaka, Takaaki; Watanabe, Shin; Takeda, Shin'ichiro; Nakazawa, Kazuhiro; Ushio, Masayoshi; Mitani, Takefumi; Takahashi, Tadayuki; Tajima, Hiroyasu

    2007-01-01

    We are developing a semiconductor Compton telescope to explore the universe in the energy band from several tens of keV to a few MeV. A detector material of combined Si strip and CdTe pixel is used to cover the energy range around 60keV. For energies above several hundred keV, in contrast, the higher detection efficiency of CdTe semiconductor in comparison with Si is expected to play an important role as both an absorber and a scatterer. In order to demonstrate the spectral and imaging capability of a CdTe-based Compton camera, we developed a Compton telescope consisting of a stack of CdTe pixel detectors as a small scale prototype. With this prototype, we succeeded in reconstructing images and spectra by solving the Compton kinematics within the energy band from 122 to 662keV. The energy resolution (FWHM) of reconstructed spectra is 7.3keV at 511keV. The angular resolution obtained at 511keV is measured to be 12.2 deg. (FWHM)

  10. Application of a one-dimensional position-sensitive detector to a Kratky small-angle x-ray camera

    International Nuclear Information System (INIS)

    Russell, T.P.; Stein, R.S.; Kopp, M.K.; Zedler, R.E.; Hendricks, R.W.; Lin, J.S.

    1979-01-01

    A conventional Kratky small-angle collimation system has been modified to allow the use of a one-dimensional position-sensitive x-ray detector. The detector was designed specifically for use with a long-slit camera and has uniform sensitivity over the entire beam in the slit-length direction. Procedures for alignment of the collimation system are given, and a variety of tests of the performance of the system are presented. Among the latter are measurements of electronic noise and parasitic scattering as well as comparisons against samples which were also measured on other cameras. The good agreement of these comparisons demonstrates the success of the use of a position-sensitive detector with the Kratky collimation system

  11. Application of a one-dimensional position-sensitive detector to a Kratky small-angle x-ray camera

    Energy Technology Data Exchange (ETDEWEB)

    Russell, T.P.; Stein, R.S.; Kopp, M.K.; Zedler, R.E.; Hendricks, R.W.; Lin, J.S.

    1979-01-01

    A conventional Kratky small-angle collimation system has been modified to allow the use of a one-dimensional position-sensitive x-ray detector. The detector was designed specifically for use with a long-slit camera and has uniform sensitivity over the entire beam in the slit-length direction. Procedures for alignment of the collimation system are given, and a variety of tests of the performance of the system are presented. Among the latter are measurements of electronic noise and parasitic scattering as well as comparisons against samples which were also measured on other cameras. The good agreement of these comparisons demonstrates the success of the use of a position-sensitive detector with the Kratky collimation system.

  12. Simultaneous dual-radionuclide myocardial perfusion imaging with a solid-state dedicated cardiac camera.

    Science.gov (United States)

    Ben-Haim, Simona; Kacperski, Krzysztof; Hain, Sharon; Van Gramberg, Dean; Hutton, Brian F; Erlandsson, Kjell; Sharir, Tali; Roth, Nathaniel; Waddington, Wendy A; Berman, Daniel S; Ell, Peter J

    2010-08-01

    We compared simultaneous dual-radionuclide (DR) stress and rest myocardial perfusion imaging (MPI) with a novel solid-state cardiac camera and a conventional SPECT camera with separate stress and rest acquisitions. Of 27 consecutive patients recruited, 24 (64.5+/-11.8 years of age, 16 men) were injected with 74 MBq of (201)Tl (rest) and 250 MBq (99m)Tc-MIBI (stress). Conventional MPI acquisition times for stress and rest are 21 min and 16 min, respectively. Rest (201)Tl for 6 min and simultaneous DR 15-min list mode gated scans were performed on a D-SPECT cardiac scanner. In 11 patients DR D-SPECT was performed first and in 13 patients conventional stress (99m)Tc-MIBI SPECT imaging was performed followed by DR D-SPECT. The DR D-SPECT data were processed using a spill-over and scatter correction method. DR D-SPECT images were compared with rest (201)Tl D-SPECT and with conventional SPECT images by visual analysis employing the 17-segment model and a five-point scale (0 normal, 4 absent) to calculate the summed stress and rest scores. Image quality was assessed on a four-point scale (1 poor, 4 very good) and gut activity was assessed on a four-point scale (0 none, 3 high). Conventional MPI studies were abnormal at stress in 17 patients and at rest in 9 patients. In the 17 abnormal stress studies DR D-SPECT MPI showed 113 abnormal segments and conventional MPI showed 93 abnormal segments. In the nine abnormal rest studies DR D-SPECT showed 45 abnormal segments and conventional MPI showed 48 abnormal segments. The summed stress and rest scores on conventional SPECT and DR D-SPECT were highly correlated (r=0.9790 and 0.9694, respectively). The summed scores of rest (201)Tl D-SPECT and DR-DSPECT were also highly correlated (r=0.9968, pstress perfusion defects were significantly larger on stress DR D-SPECT images, and five of these patients were imaged earlier by D-SPECT than by conventional SPECT. Fast and high-quality simultaneous DR MPI is feasible with D-SPECT in a

  13. Simultaneous dual-radionuclide myocardial perfusion imaging with a solid-state dedicated cardiac camera

    International Nuclear Information System (INIS)

    Ben-Haim, Simona; Kacperski, Krzysztof; Hain, Sharon; Van Gramberg, Dean; Hutton, Brian F.; Erlandsson, Kjell; Waddington, Wendy A.; Ell, Peter J.; Sharir, Tali; Roth, Nathaniel; Berman, Daniel S.

    2010-01-01

    We compared simultaneous dual-radionuclide (DR) stress and rest myocardial perfusion imaging (MPI) with a novel solid-state cardiac camera and a conventional SPECT camera with separate stress and rest acquisitions. Of 27 consecutive patients recruited, 24 (64.5±11.8 years of age, 16 men) were injected with 74 MBq of 201 Tl (rest) and 250 MBq 99m Tc-MIBI (stress). Conventional MPI acquisition times for stress and rest are 21 min and 16 min, respectively. Rest 201 Tl for 6 min and simultaneous DR 15-min list mode gated scans were performed on a D-SPECT cardiac scanner. In 11 patients DR D-SPECT was performed first and in 13 patients conventional stress 99m Tc-MIBI SPECT imaging was performed followed by DR D-SPECT. The DR D-SPECT data were processed using a spill-over and scatter correction method. DR D-SPECT images were compared with rest 201 Tl D-SPECT and with conventional SPECT images by visual analysis employing the 17-segment model and a five-point scale (0 normal, 4 absent) to calculate the summed stress and rest scores. Image quality was assessed on a four-point scale (1 poor, 4 very good) and gut activity was assessed on a four-point scale (0 none, 3 high). Conventional MPI studies were abnormal at stress in 17 patients and at rest in 9 patients. In the 17 abnormal stress studies DR D-SPECT MPI showed 113 abnormal segments and conventional MPI showed 93 abnormal segments. In the nine abnormal rest studies DR D-SPECT showed 45 abnormal segments and conventional MPI showed 48 abnormal segments. The summed stress and rest scores on conventional SPECT and DR D-SPECT were highly correlated (r=0.9790 and 0.9694, respectively). The summed scores of rest 201 Tl D-SPECT and DR-DSPECT were also highly correlated (r=0.9968, p 201 Tl D-SPECT acquisition. (orig.)

  14. Ionization dual-zone static detector having single radioactive source

    International Nuclear Information System (INIS)

    Ried, L. Jr.; Wade, A.L.

    1977-01-01

    This ionization detector or combustion product detector includes a single radioactive source located in an ionization chamber, and the ionization chamber includes portions comprising a reference zone and a signal zone. Electrical circuitry connected to the reference and signal zones provides an output signal directly related to changes in voltages across the signal zone in relation to the amount of particulates of combustion present in the ionization chamber

  15. Monte Carlo simulation of determining porosity by using dual gamma detectors

    International Nuclear Information System (INIS)

    Zhang Feng; Liu Juntao; Yu Huawei; Yuan Chao; Jia Yan

    2013-01-01

    Current formation elements spectroscopy logging technology utilize 241 Am-Be neutron source and single BGO detector to determine elements contents. It plays an important role in mineral analysis and lithology identification of unconventional oil and gas exploration, but information measured is relatively ld. Measured system based on 241 Am-Be neutron and dual detectors can be developed to realize the measurement of elements content as well as determine neutron gamma porosity by using ratio of gamma count between near and far detectors. Calculation model is built by Monte Carlo method to study neutron gamma porosity logging response with different spacing and shields. And it is concluded that measuring neutron gamma have high counts and good statistical property contrasted with measuring thermal neutron, but the sensitivity of porosity decrease. Sensitivity of porosity will increase as the spacing of dual detector increases. Spacing of far and near detectors should be around 62 cm and 35 cm respectively. Gamma counts decrease and neutron gamma porosity sensitivity increase when shield is fixed between neutron and detector. The length of main shield should be greater than 10 cm and associated shielding is about 5 cm. By Monte Carlo Simulation study, the result provides technical support for determining porosity in formation elements spectroscopy logging using 241 Am-Be neutron and gamma detectors. (authors)

  16. Development of Strained-Layer Superlattice (SLS) IR Detector Camera Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Strained Layer Superlattice (SLS) detectors are a new class of detectors which may be the next generation of band-gap engineered, large format infrared detector...

  17. SU-D-BRC-07: System Design for a 3D Volumetric Scintillation Detector Using SCMOS Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Darne, C; Robertson, D; Alsanea, F; Beddar, S [UT MD Anderson Cancer Center, Houston, TX (United States)

    2016-06-15

    Purpose: The purpose of this project is to build a volumetric scintillation detector for quantitative imaging of 3D dose distributions of proton beams accurately in near real-time. Methods: The liquid scintillator (LS) detector consists of a transparent acrylic tank (20×20×20 cm{sup 3}) filled with a liquid scintillator that when irradiated with protons generates scintillation light. To track rapid spatial and dose variations in spot scanning proton beams we used three scientific-complementary metal-oxide semiconductor (sCMOS) imagers (2560×2160 pixels). The cameras collect optical signal from three orthogonal projections. To reduce system footprint two mirrors oriented at 45° to the tank surfaces redirect scintillation light to cameras for capturing top and right views. Selection of fixed focal length objective lenses for these cameras was based on their ability to provide large depth of field (DoF) and required field of view (FoV). Multiple cross-hairs imprinted on the tank surfaces allow for image corrections arising from camera perspective and refraction. Results: We determined that by setting sCMOS to 16-bit dynamic range, truncating its FoV (1100×1100 pixels) to image the entire volume of the LS detector, and using 5.6 msec integration time imaging rate can be ramped up to 88 frames per second (fps). 20 mm focal length lens provides a 20 cm imaging DoF and 0.24 mm/pixel resolution. Master-slave camera configuration enable the slaves to initiate image acquisition instantly (within 2 µsec) after receiving a trigger signal. A computer with 128 GB RAM was used for spooling images from the cameras and can sustain a maximum recording time of 2 min per camera at 75 fps. Conclusion: The three sCMOS cameras are capable of high speed imaging. They can therefore be used for quick, high-resolution, and precise mapping of dose distributions from scanned spot proton beams in three dimensions.

  18. SU-D-BRC-07: System Design for a 3D Volumetric Scintillation Detector Using SCMOS Cameras

    International Nuclear Information System (INIS)

    Darne, C; Robertson, D; Alsanea, F; Beddar, S

    2016-01-01

    Purpose: The purpose of this project is to build a volumetric scintillation detector for quantitative imaging of 3D dose distributions of proton beams accurately in near real-time. Methods: The liquid scintillator (LS) detector consists of a transparent acrylic tank (20×20×20 cm"3) filled with a liquid scintillator that when irradiated with protons generates scintillation light. To track rapid spatial and dose variations in spot scanning proton beams we used three scientific-complementary metal-oxide semiconductor (sCMOS) imagers (2560×2160 pixels). The cameras collect optical signal from three orthogonal projections. To reduce system footprint two mirrors oriented at 45° to the tank surfaces redirect scintillation light to cameras for capturing top and right views. Selection of fixed focal length objective lenses for these cameras was based on their ability to provide large depth of field (DoF) and required field of view (FoV). Multiple cross-hairs imprinted on the tank surfaces allow for image corrections arising from camera perspective and refraction. Results: We determined that by setting sCMOS to 16-bit dynamic range, truncating its FoV (1100×1100 pixels) to image the entire volume of the LS detector, and using 5.6 msec integration time imaging rate can be ramped up to 88 frames per second (fps). 20 mm focal length lens provides a 20 cm imaging DoF and 0.24 mm/pixel resolution. Master-slave camera configuration enable the slaves to initiate image acquisition instantly (within 2 µsec) after receiving a trigger signal. A computer with 128 GB RAM was used for spooling images from the cameras and can sustain a maximum recording time of 2 min per camera at 75 fps. Conclusion: The three sCMOS cameras are capable of high speed imaging. They can therefore be used for quick, high-resolution, and precise mapping of dose distributions from scanned spot proton beams in three dimensions.

  19. Positron emission mammography with tomographic acquisition using dual planar detectors: initial evaluations

    International Nuclear Information System (INIS)

    Smith, Mark F; Raylman, Raymond R; Majewski, Stan; Weisenberger, Andrew G

    2004-01-01

    Positron emission mammography (PEM) with tomographic acquisition using dual planar detectors rotating about the breast can obtain complete angular sampling and has the potential to improve activity estimation compared with PEM using stationary detectors. PEM tomography (PEMT) was compared with stationary PEM for point source and compressed breast phantom studies performed with a compact dual detector system. The acquisition geometries were appropriate for the target application of PEM guidance of stereotactic core biopsy. Images were reconstructed with a three-dimensional iterative maximum likelihood expectation maximization algorithm. PEMT eliminated blurring normal to the detectors seen with stationary PEM. Depth of interaction effects distorted the shape of the point spread functions for PEMT as the angular range from normal incidence of lines of response used in image reconstruction increased. Streak artefacts in PEMT for large detector rotation increments led to the development of an expression for the maximum rotation increment that maintains complete angular sampling. Studies with a compressed breast phantom were used to investigate contrast and signal-to-noise ratio (SNR) trade-offs for different sized spherical tumour models. PEMT and PEM both had advantages depending on lesion size and detector separation. The most appropriate acquisition method for specific detection or quantitation tasks requires additional investigation

  20. Usefulness of FDG PET for nodal staging using a dual head coincidence camera in patients with lung cancer

    International Nuclear Information System (INIS)

    Yoon, Seok Nam; Park, Chan H.; Lee, Myoung Hoon; Hwang, Kyung Hoon; Hwang, Kyung Hoon

    2001-01-01

    Staging of lung cancer requires an accurate evaluation of the mediastinum. Positron imaging with dual head cameras may be not as sensitive as dedicated PET. Therefore, the purpose of the study was to evaluated the usefulness of F-18 FDG coincidence (CoDe) PET using a dual-head gamma camera in the nodal staging of the lung cancer. CoDe-PET studies were performed in 51 patients with histologically proven non small cell lung cancer. CoDe-PET began 60 minutes after the injection of 111-185 MBq of F-18 FDG. CoDe-PET was performed using a dual-head gamma camera equipped with coincidence detection circuitry (Elscints Varicam, Haifa, lsrael). There was no attenuation correction made and reconstruction was done using a filtered back-projection. Surgery was performed in 49 patients CoDe-PET studies were evaluated visually. Any focal increased uptake was considered abnormal. The nodal stating of CoDe-PET studies were evaluated visually. Any focal increased uptake was considered abnormal. The nodal staging of CoDe-PET and of CT were compared with the nodal stating of surgical (49) and mediastinoscopical (2) pathology. All primary lung lesions were hypermetabolic and easily visualized. Compared with surgical nodal staging as a gold standard, false positives occurred in 13 CoDe PET and 17 CT studies and false negative occurred in 5 CoDe-PET and 4 CT studies. Assessment of lymph node involvement by CoDe-PET depicted a sensitivity of 67%, specificity of 64% and accuracy of 65%. CT revealed a sensitivity of 73%, specificity of 53% and accuracy of 59% in the assessment of lymph node involvement. The detection of primary lesions were 100% but nodal staging was suboptimal for routine clinical use. This is mainly due to limited resolution of our system

  1. Adaptive algorithms of position and energy reconstruction in Anger-camera type detectors: experimental data processing in ANTS

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, A; Fraga, F A F; Fraga, M M F R; Margato, L M S; Pereira, L [LIP-Coimbra and Departamento de Física, Universidade de Coimbra, Rua Larga, Coimbra (Portugal); Defendi, I; Jurkovic, M [Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), TUM, Lichtenbergstr. 1, Garching (Germany); Engels, R; Kemmerling, G [Zentralinstitut für Elektronik, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, Jülich (Germany); Gongadze, A; Guerard, B; Manzin, G; Niko, H; Peyaud, A; Piscitelli, F [Institut Laue Langevin, 6 Rue Jules Horowitz, Grenoble (France); Petrillo, C; Sacchetti, F [Istituto Nazionale per la Fisica della Materia, Unità di Perugia, Via A. Pascoli, Perugia (Italy); Raspino, D; Rhodes, N J; Schooneveld, E M, E-mail: andrei@coimbra.lip.pt [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot (United Kingdom); others, and

    2013-05-01

    The software package ANTS (Anger-camera type Neutron detector: Toolkit for Simulations), developed for simulation of Anger-type gaseous detectors for thermal neutron imaging was extended to include a module for experimental data processing. Data recorded with a sensor array containing up to 100 photomultiplier tubes (PMT) or silicon photomultipliers (SiPM) in a custom configuration can be loaded and the positions and energies of the events can be reconstructed using the Center-of-Gravity, Maximum Likelihood or Least Squares algorithm. A particular strength of the new module is the ability to reconstruct the light response functions and relative gains of the photomultipliers from flood field illumination data using adaptive algorithms. The performance of the module is demonstrated with simulated data generated in ANTS and experimental data recorded with a 19 PMT neutron detector. The package executables are publicly available at http://coimbra.lip.pt/∼andrei/.

  2. Using a Borated Panel to Form a Dual Neutron-Gamma Detector

    Energy Technology Data Exchange (ETDEWEB)

    Scott Wilde; Raymond Keegan

    2008-06-20

    A borated polyethylene plane placed between a neutron source and a gamma spectrometer is used to form a dual neutron-gamma detection system. The polyethylene thermalizes the source neutrons so that they are captured by {sup 10}B to produce a flux of 478 keV gamma-rays that radiate from the plane. This results in a buildup of count rate in the detector over that from a disk of the same diameter as the detector crystal (same thickness as the panel). Radiation portal systems are a potential application of this technique.

  3. Automated testing of microstrip detectors readout system for dual x-ray dual energy

    International Nuclear Information System (INIS)

    Bolanos, L.; Cabal, A. E.; Diaz, A.; Swientek, K.; Giubellino, P.; Marzari-Chiesa, A.; Prino, F.; Ramello, L.

    2008-01-01

    Circuits that carry out the signal acquisition and processing by multiple channels are required in digital radiography. These circuits should be tested in order to characterize their performance. This paper describes an automated system to control (by a software, from a personal computer) the characterization of a system based on RX64DTH specific integrated circuits with microstrip detectors. The results are shown. (Author)

  4. Dual photon absorptiometer utilizing a HpGe detector and microprocessor controller

    International Nuclear Information System (INIS)

    Ellis, K.J.; Vartsky, D.; Pearlstein, T.B.; Alberi, J.L.; Cohn, S.H.

    1978-01-01

    The analysis of bone mineral content (BMC) using a single energy-photon beam assumes that there are only two materials present, bone mineral and a uniform soft tissue component. Uncertainty in the value of BMC increases with different adipose tissue components in the transmitted beam. These errors, however, are reduced by the dual energy technique. Also, extension to additional energies further identifies the separate constituents of the soft tissue component. A multi-energy bone scanning apparatus with data acquisition and analysis capability sufficient to perform multi-energy analysis of bone mineral content was designed and developed. The present work reports on the development of device operated in the dual energy mode. The high purity germanium (HpGe) detector is an integral component of the scanner. Errors in BMC due to multiple small angle scatters are reduced due to the excellent energy resolution of the detector (530 eV at 60 keV). Also, the need to filter the source or additional collimation on the detector is eliminated. A new dual source holder was designed using 200 mCi 125 I and 100 mCi 241 Am. The active areas of the two source capsules are aligned on a common axis. The congruence of the dual source was verified by measuring the collimator response function. This new holder design insures that the same tissue mass simultaneously attenuates both sources. The controller portion of the microprocessor allows for variation in total scan length, step size, and counting time per step. These options allow for multiple measurements without changes in the detector, source, or collimator. The system has been successfully used to determine the BMC content of different bones

  5. A proposal of decontamination robot using 3D hand-eye-dual-cameras solid recognition and accuracy validation

    International Nuclear Information System (INIS)

    Minami, Mamoru; Nishimura, Kenta; Sunami, Yusuke; Yanou, Akira; Yu, Cui; Yamashita, Manabu; Ishiyama, Shintaro

    2015-01-01

    New robotic system that uses three dimensional measurement with solid object recognition —3D-MOS (Three Dimensional Move on Sensing)— based on visual servoing technology was designed and the on-board hand-eye-dual-cameras robot system has been developed to reduce risks of radiation exposure during decontamination processes by filter press machine that solidifies and reduces the volume of irradiation contaminated soil. The feature of 3D-MoS includes; (1) the both hand-eye-dual-cameras take the images of target object near the intersection of both lenses' centerlines, (2) the observation at intersection enables both cameras can see target object almost at the center of both images, (3) then it brings benefits as reducing the effect of lens aberration and improving the detection accuracy of three dimensional position. In this study, accuracy validation test of interdigitation of the robot's hand into filter cloth rod of the filter press —the task is crucial for the robot to remove the contaminated cloth from the filter press machine automatically and for preventing workers from exposing to radiation—, was performed. Then the following results were derived; (1) the 3D-MoS controlled robot could recognize the rod at arbitrary position within designated space, and all of insertion test were carried out successfully and, (2) test results also demonstrated that the proposed control guarantees that interdigitation clearance between the rod and robot hand can be kept within 1.875[mm] with standard deviation being 0.6[mm] or less. (author)

  6. A theoretical investigation of spectra utilization for a CMOS based indirect detector for dual energy applications

    International Nuclear Information System (INIS)

    Kalyvas, N; Michail, C; Valais, I; Kandarakis, I; Fountos, G; Martini, N; Koukou, V; Sotiropoulou, P

    2015-01-01

    Dual Energy imaging is a promising method for visualizing masses and microcalcifications in digital mammography. Currently commercially available detectors may be suitable for dual energy mammographic applications. The scope of this work was to theoretically examine the performance of the Radeye CMOS digital indirect detector under three low- and high-energy spectral pairs. The detector was modeled through the linear system theory. The pixel size was equal to 22.5μm and the phosphor material of the detector was a 33.9 mg/cm 2 Gd 2 O 2 S:Tb phosphor screen. The examined spectral pairs were (i) a 40kV W/Ag (0.01cm) and a 70kV W/Cu (0.1cm) target/filter combinations, (ii) a 40kV W/Cd (0.013cm) and a 70kV W/Cu (0.1cm) target/filter combinations and (iii) a 40kV W/Pd (0.008cm) and a 70kV W/Cu (0.1cm) target/filter combinations. For each combination the Detective Quantum Efficiency (DQE), showing the signal to noise ratio transfer, the detector optical gain (DOG), showing the sensitivity of the detector and the coefficient of variation (CV) of the detector output signal were calculated. The second combination exhibited slightly higher DOG (326 photons per X-ray) and lower CV (0.755%) values. In terms of electron output from the RadEye CMOS, the first two combinations demonstrated comparable DQE values; however the second combination provided an increase of 6.5% in the electron output. (paper)

  7. Commissioning of the scatter component of a Compton camera consisting of a stack of Si strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Liprandi, S.; Marinsek, T.; Bortfeldt, J.; Lang, C.; Lutter, R.; Dedes, G.; Parodi, K.; Thirolf, P.G. [LMU Munich, Garching (Germany); Aldawood, S. [LMU Munich, Garching (Germany); King Saud University, Riyadh (Saudi Arabia); Maier, L.; Gernhaeuser, R. [TU Munich, Garching (Germany); Kolff, H. van der [LMU Munich, Garching (Germany); TU Delft (Netherlands); Castelhano, I. [LMU Munich, Garching (Germany); University of Lisbon, Lisbon (Portugal); Schaart, D.R. [TU Delft (Netherlands)

    2015-07-01

    At LMU Munich in Garching a Compton camera is presently being developed aiming at the range verification of proton (or ion) beams for hadron therapy via imaging of prompt γ rays from nuclear reactions in the tissue. The poster presentation focuses on the characterization of the scatter component of the Compton camera, consisting of a stack of six double-sided Si strip detectors (50 x 50 mm{sup 2}, 0.5 mm thick, 128 strips/side). The overall 1536 electronics channels are processed by a readout system based on the GASSIPLEX ASIC chip, feeding into a VME-based data acquisition system. The status of the offline and online characterization studies is presented.

  8. EXPERIMENTAL AND MONTE CARLO INVESTIGATIONS OF BCF-12 SMALL‑AREA PLASTIC SCINTILLATION DETECTORS FOR NEUTRON PINHOLE CAMERA.

    Science.gov (United States)

    Bielecki, J; Drozdowicz, K; Dworak, D; Igielski, A; Janik, W; Kulinska, A; Marciniak, L; Scholz, M; Turzanski, M; Wiacek, U; Woznicka, U; Wójcik-Gargula, A

    2017-12-11

    Plastic organic scintillators such as the blue-emitting BCF-12 are versatile and inexpensive tools. Recently, BCF-12 scintillators have been foreseen for investigation of the spatial distribution of neutrons emitted from dense magnetized plasma. For this purpose, small-area (5 mm × 5 mm) detectors based on BCF-12 scintillation rods and Hamamatsu photomultiplier tubes were designed and constructed at the Institute of Nuclear Physics. They will be located inside the neutron pinhole camera of the PF-24 plasma focus device. Two different geometrical layouts and approaches to the construction of the scintillation element were tested. The aim of this work was to determine the efficiency of the detectors. For this purpose, the experimental investigations using a neutron generator and a Pu-Be source were combined with Monte Carlo computations using the Geant4 code. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. A dual layer DOI GSO block detector for a small animal PET

    International Nuclear Information System (INIS)

    Yamamoto, Seiichi

    2009-01-01

    For a high resolution animal positron emission tomography (PET), depth-of-interaction (DOI) is a useful method to improve both spatial resolution and sensitivity. Gd 2 SiO 5 (GSO) with different amounts of Ce can provide different decay times and is ideal for DOI detector using pulse shape analysis. Dual layer DOI GSO block detectors using different amounts of Ce were developed for a new animal PET. The DOI GSO block detector employed two types of GSOs; one with 1.5 mol% Ce concentration (decay time: 35 ns) and the other with 0.5 mol% (decay time: 60 ns). These two GSO types were optically coupled in the DOI direction. The sizes of single GSOs were 1.9 mmx1.9 mmx6 mm and 1.9 mmx1.9 mmx9 mm, for 1.5 and 0.5 mol%, respectively. These GSO were arranged by 11x37 matrix and optically coupled to three position sensitive photomultiplier tubes (PSPMTs), where the PSPMTs used were Hamamatsu R8520U-00-C12. Different lengths of reflectors were used between crystals to increase the useful field-of-view (FOV) of the PSPMT and to avoid the dead areas between PSPMTs. With this configuration, almost all islands in a 2-D position histogram corresponding to GSO cells could be separated. The width of the GSO block was 22 mm in the transaxial direction and 74 mm in axial direction with no gaps. Also, two types of GSO of different decay time could be separated using dual integration method for pulse shape analysis. These results indicate that developed block detectors might be useful for a high resolution and high sensitivity animal PET with dual layer DOI detection capability, with no gaps in transaxial or axial directions.

  10. Gamma camera

    International Nuclear Information System (INIS)

    Schlosser, P.A.; Steidley, J.W.

    1980-01-01

    The design of a collimation system for a gamma camera for use in nuclear medicine is described. When used with a 2-dimensional position sensitive radiation detector, the novel system can produce superior images than conventional cameras. The optimal thickness and positions of the collimators are derived mathematically. (U.K.)

  11. A novel high resolution and high efficiency dual head detector for molecular breast imaging: New results from clinical trials

    Energy Technology Data Exchange (ETDEWEB)

    Garibaldi, F., E-mail: franco.garibaldi@iss.infn.i [ISS and INFN Roma, gr. Sanita, Rome (Italy); Cisbani, E.; Colilli, S.; Cusanno, F.; Fratoni, R.; Giuliani, F.; Gricia, M.; Lucentini, M.; Magliozzi, M.L.; Santavenere, F.; Torrioli, S. [ISS and INFN Roma, gr. Sanita, Rome (Italy); Musico, P. [INFN Genova, Genova (Italy); Argentieri, A. [INFN Bari, Bari (Italy); Cossu, E.; Padovano, F.; Simonetti, G. [ISS and INFN Roma, gr. Sanita, Rome (Italy); Schillaci, O. [University of Tor Vergata, Rome (Italy); Majewski, S. [West Virginia University, Morgantown, West Virginia (United States)

    2010-05-21

    Detecting small breast tumors is a challenging task. Molecular Breast Imaging with radionuclides has a central role to play in this respect. Our group has recently designed and implemented a dual detector setup that allows spot compression and improves significantly the performance of the system. The single head detector has been successfully used for clinical trials with 10 patients in comparison with a commercial high resolution detector. Then the dual head system has been showed to have significant advantages for the detection of small tumors.

  12. Quality control in dual head γ-cameras: comparison between methods and software s used for image analysis

    International Nuclear Information System (INIS)

    Nayl E, A.; Fornasier, M. R.; De Denaro, M.; Sulieman, A.; Alkhorayef, M.; Bradley, D.

    2017-10-01

    Patient radiation dose and image quality are the main issues in nuclear medicine (Nm) procedures. Currently, many protocols are used for image acquisition and analysis of quality control (Qc) tests. National Electrical Manufacturers Association (Nema) methods and protocols are widely accepted method used for providing accurate description, measurement and reporting of γ-camera performance parameters. However, no standard software is available for image analysis. The aim os this study was to compare between the vendor Qc software analysis and three software from different developers downloaded free from internet; NMQC, Nm Tool kit and ImageJ-Nm Tool kit software. The three software are used for image analysis of some Qc tests for γ-cameras based on Nema protocols including non-uniformity evaluation. Ten non-uniformity Qc images were taken from dual head γ-camera (Siemens Symbia) installed in Trieste general hospital (Italy), and analyzed. Excel analysis was used as baseline calculation of the non-uniformity test according Nema procedures. The results of the non-uniformity analysis showed good agreement between the three independent software and excel calculation (the average differences were 0.3%, 2.9%, 1.3% and 1.6% for UFOV integral, UFOV differential, CFOV integral and CFOV differential respectively), while significant difference was detected on the analysis of the company Qc software with compare to the excel analysis (the average differences were 14.6%, 20.7%, 25.7% and 31.9% for UFOV integral, UFOV differential, CFOV integral and CFOV differential respectively). NMQC software was the best in comparison with the excel calculations. The variation in the results is due to different pixel sizes used for analysis in the three software and the γ-camera Qc software. Therefore, is important to perform the tests by the vendor Qc software as well as by independent analysis to understand the differences between the values. Moreover, the medical physicist should know

  13. Quality control in dual head γ-cameras: comparison between methods and software s used for image analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nayl E, A. [Sudan Atomic Energy Commission, Radiation Safety Institute, Khartoum (Sudan); Fornasier, M. R.; De Denaro, M. [Azienda Sanitaria Universitaria Integrata di Trieste, Medical Physics Department, Via Giovanni Sai 7, 34128 Trieste (Italy); Sulieman, A. [Prince Sattam bin Abdulaziz University, College of Applied Medical Sciences, Radiology and Medical Imaging Department, P. O. Box 422, 11942 Al-Kharj (Saudi Arabia); Alkhorayef, M.; Bradley, D., E-mail: abdwsh10@hotmail.com [University of Surrey, Department of Physics, GU2-7XH Guildford, Surrey (United Kingdom)

    2017-10-15

    Patient radiation dose and image quality are the main issues in nuclear medicine (Nm) procedures. Currently, many protocols are used for image acquisition and analysis of quality control (Qc) tests. National Electrical Manufacturers Association (Nema) methods and protocols are widely accepted method used for providing accurate description, measurement and reporting of γ-camera performance parameters. However, no standard software is available for image analysis. The aim os this study was to compare between the vendor Qc software analysis and three software from different developers downloaded free from internet; NMQC, Nm Tool kit and ImageJ-Nm Tool kit software. The three software are used for image analysis of some Qc tests for γ-cameras based on Nema protocols including non-uniformity evaluation. Ten non-uniformity Qc images were taken from dual head γ-camera (Siemens Symbia) installed in Trieste general hospital (Italy), and analyzed. Excel analysis was used as baseline calculation of the non-uniformity test according Nema procedures. The results of the non-uniformity analysis showed good agreement between the three independent software and excel calculation (the average differences were 0.3%, 2.9%, 1.3% and 1.6% for UFOV integral, UFOV differential, CFOV integral and CFOV differential respectively), while significant difference was detected on the analysis of the company Qc software with compare to the excel analysis (the average differences were 14.6%, 20.7%, 25.7% and 31.9% for UFOV integral, UFOV differential, CFOV integral and CFOV differential respectively). NMQC software was the best in comparison with the excel calculations. The variation in the results is due to different pixel sizes used for analysis in the three software and the γ-camera Qc software. Therefore, is important to perform the tests by the vendor Qc software as well as by independent analysis to understand the differences between the values. Moreover, the medical physicist should know

  14. Design of dual energy x-ray detector for conveyor belt with steel wire ropes

    Science.gov (United States)

    Dai, Yue; Miao, Changyun; Rong, Feng

    2009-07-01

    A dual energy X-ray detector for conveyor belt with steel wire ropes is researched in the paper. Conveyor belt with steel wire ropes is one of primary transfer equipments in modern production. The traditional test methods like electromagnetic induction principle could not display inner image of steel wire ropes directly. So X-ray detection technology has used to detect the conveyor belt. However the image was not so clear by the interference of the rubber belt. Therefore, the dualenergy X-ray detection technology with subtraction method is developed to numerically remove the rubber belt from radiograph, thus improving the definition of the ropes image. The purpose of this research is to design a dual energy Xray detector that could make the operator easier to found the faulty of the belt. This detection system is composed of Xray source, detector controlled by FPGA chip, PC for running image processing system and so on. With the result of the simulating, this design really improved the capability of the staff to test the conveyor belt.

  15. Use of dual-head gamma camera in radionuclide internal contamination monitoring on radiation workers from a nuclear medicine department

    International Nuclear Information System (INIS)

    Rodriguez-Laguna, A.; Brandan, M.E.

    2008-01-01

    As a part of an internal dosimetry program that is performed at the Mexican National Institute of Cancerology - Nuclear Medicine Department, in the present work we suggest a procedure for the routinely monitoring of internal contamination on radiation workers and nuclear medicine staff. The procedure is based on the identification and quantification of contaminating radionuclides in human body by using a dual-head whole-body gamma camera. The results have shown that the procedures described in this study can be used to implement a method to quantify minimal accumulated activity in the main human organs to evaluate internal contamination with radionuclides. The high sensitivity of the uncollimated gamma camera is advantageous for the routinely detection and identification of small activities of internal contamination. But, the null spatial resolution makes impossible the definition of contaminated region of interest. Then, the use of collimators is necessary to the quantification of incorporated radionuclides activities in the main human organs and for the internal doses assessment. (author)

  16. Control sideband generation for dual-recycled laser interferometric gravitational wave detectors

    International Nuclear Information System (INIS)

    Barr, B W; Miyakawa, O; Kawamura, S; Weinstein, A J; Ward, R; Vass, S; Strain, K A

    2006-01-01

    We present a discussion of the problems associated with generation of multiple control sidebands for length sensing and control of dual-recycled, cavity-enhanced Michelson interferometers and the motivation behind more complicated sideband generation methods. We focus on the Mach-Zehnder interferometer as a topological solution to the problem and present results from tests carried out at the Caltech 40 m prototype gravitational wave detector. The consequences for sensing and control for advanced interferometry are discussed, as are the implications for future interferometers such as Advanced LIGO

  17. Development of silicon pad detectors and readout electronics for a Compton camera

    CERN Document Server

    Studen, A; Clinthorne, N H; Czermak, A; Dulinski, W; Fuster, J A; Han, L; Jalocha, P; Kowal, M; Kragh, T; Lacasta, C; Llosa, G; Meier, D; Mikuz, M; Nygård, E; Park, S J; Roe, S; Rogers, W L; Sowicki, B; Weilhammer, P; Wilderman, S J; Yoshioka, K; Zhang, L

    2003-01-01

    Applications in nuclear medicine and bio-medical engineering may profit using a Compton camera for imaging distributions of radio-isotope labelled tracers in organs and tissues. These applications require detection of photons using thick position-sensitive silicon sensors with the highest possible energy and good spatial resolution. In this paper, research and development on silicon pad sensors and associated readout electronics for a Compton camera are presented. First results with low-noise, self-triggering VATAGP ASIC's are reported. The measured energy resolution was 1.1 keV FWHM at room temperature for the sup 2 sup 4 sup 1 Am photo-peak at 59.5 keV.

  18. An instrumentation amplifier based readout circuit for a dual element microbolometer infrared detector

    Science.gov (United States)

    de Waal, D. J.; Schoeman, J.

    2014-06-01

    The infrared band is widely used in many applications to solve problems stretching over very diverse fields, ranging from medical applications like inflammation detection to military, security and safety applications employing thermal imaging in low light conditions. At the heart of these optoelectrical systems lies a sensor used to detect incident infrared radiation, and in the case of this work our focus is on uncooled microbolometers as thermal detectors. Microbolometer based thermal detectors are limited in sensitivity by various parameters, including the detector layout and design, operating temperature, air pressure and biasing that causes self heating. Traditional microbolometers use the entire membrane surface for a single detector material. This work presents the design of a readout circuit amplifier where a dual detector element microbolometer is used, rather than the traditional single element. The concept to be investigated is based on the principle that both elements will be stimulated with a similar incoming IR signal and experience the same resistive change, thus creating a common mode signal. However, such a common mode signal will be rejected by a differential amplifier, thus one element is placed within a negative resistance converter to create a differential mode signal that is twice the magnitude of the comparable single mode signal of traditional detector designs. An instrumentation amplifier is used for the final stage of the readout amplifier circuit, as it allows for very high common mode rejection with proper trimming of the Wheatstone bridge to compensate for manufacturing tolerance. It was found that by implementing the above, improved sensitivity can be achieved.

  19. Dual aerosol detector based on forward light scattering with a single laser beam

    International Nuclear Information System (INIS)

    Kovach, B.J.; Custer, R.A.; Powers, F.L.; Kovach, A.

    1985-01-01

    The in-place leak testing of HEPA filter banks using a single detector can lead to some error in the measurement due to the fluctuation of the aerosol concentration while the single detector is being switched from the upstream to downstream sampling. The time duration of the test also can cause unnecessarily high DOP loading of the HEPA filters and in some cases higher radiation exposure to the testing personnel. The new forward light scattering detector uses one 632.8 nm laser beam for aerosol detection in a dual chamber sampling and detecting aerosol concentration simultaneously both upstream and downstream. This manner of operation eliminates the errors caused by concentration variations between upstream and downstream sample points while the switching takes place. The new detector uses large area silicone photodiodes with a hole in the center, to permit uninterrupted passage of the laser beam through the downstream sample chamber. The nonlinearity due to the aerosol over population of the laser beam volume is calculated to be less than 1% using a Poisson distribution method to determine the average distance of the particles. A simple pneumatic system prevents mixing of the upstream and downstream samples even in wide pressure variations of the duct system

  20. Depth of interaction calibration for PET detectors with dual-ended readout by PSAPDs

    International Nuclear Information System (INIS)

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

    2009-01-01

    Many laboratories develop depth-encoding detectors to improve the trade-off between spatial resolution and sensitivity in positron emission tomography (PET) scanners. One challenge in implementing these detectors is the need to calibrate the depth of interaction (DOI) response for the large numbers of detector elements in a scanner. In this work, we evaluate two different methods, a linear detector calibration and a linear crystal calibration, for determining DOI calibration parameters. Both methods can use measurements from any source distribution and location, or even the intrinsic lutetium oxyorthosilicate (LSO) background activity, and are therefore well suited for use in a depth-encoding PET scanner. The methods were evaluated by measuring detector and crystal DOI responses for all eight detectors in a prototype depth-encoding PET scanner. The detectors utilize dual-ended readout of LSO scintillator arrays with position-sensitive avalanche photodiodes (PSAPDs). The LSO arrays have 7 x 7 elements, with a crystal size of 0.92 x 0.92 x 20 mm 3 and pitch of 1.0 mm. The arrays are read out by two 8 x 8 mm 2 area PSAPDs placed at opposite ends of the arrays. DOI is measured by the ratio of the amplitude of the total energy signals measured by the two PSAPDs. Small variations were observed in the DOI responses of different crystals within an array as well as DOI responses for different arrays. A slightly nonlinear dependence of the DOI ratio on depth was observed and the nonlinearity was larger for the corner and edge crystals. The DOI calibration parameters were obtained from the DOI responses measured in a singles mode. The average error between the calibrated DOI and the known DOI was 0.8 mm if a linear detector DOI calibration was used and 0.5 mm if a linear crystal DOI calibration was used. A line source phantom and a hot rod phantom were scanned on the prototype PET scanner. DOI measurement significantly improved the image spatial resolution no matter which DOI

  1. Comparison of single and dual layer detector blocks for pre-clinical MRI–PET

    International Nuclear Information System (INIS)

    Thompson, Christopher; Stortz, Greg; Goertzen, Andrew; Berg, Eric; Retière, Fabrice; Kozlowski, Piotr; Ryner, Lawrence; Sossi, Vesna; Zhang, Xuezhu

    2013-01-01

    Dual or multi-layer crystal blocks have been proposed to minimise the radial blurring effect in PET scanners with small ring diameters. We measured two potential PET detector blocks' performance in a configuration which would allow 16 blocks in a ring which could be inserted in a small animal 7T MRI scanner. Two crystal sizes, 1.60×1.60 mm 2 and 1.20×1.20 mm 2 , were investigated. Single layer blocks had 10 or 12 mm deep crystals, the dual layer blocks had 4 mm deep crystals on the top layer and 6 mm deep crystals on the bottom layer. The crystals in the dual layer blocks are offset by ½ of the crystal pitch to allow for purely geometric crystal identification. Both were read out with SensL 4×4 SiPM arrays. The software identifies 64 crystals in the single layer and either 85 or 113 crystals in the dual layer array, (either 49 or 64 in the lower layers and 36 or 49 in the upper layers). All the crystals were clearly visible in the crystal identification images and their resolvability indexes (average FWHM/crystal separation) were shown to range from 0.29 for the best single layer block to 0.33 for the densest dual layer block. The best coincidence response FWHM was 0.95 mm for the densest block at the centre of the field. This degraded to 1.83 mm at a simulated radial offset of 16 mm from the centre, while the single layer crystals blurred this result to 3.4 mm. The energy resolution was 16.4±2.2% averaged over the 113 crystals of the densest block

  2. The effect of the rotational orientation of circular photomultipliers in a PET camera block detector design

    International Nuclear Information System (INIS)

    Uribe, J.; Wong, Wai-Hoi; Hu, Guoju

    1996-01-01

    This is a study of the effects of geometric asymmetries in circular photomultipliers (PMT) on the design of PET position-sensitive block detectors. The dynodes of linear-focus circular PMT's are asymmetric relative to the axis of the photocathode, despite the rotational symmetry of the photocathode. Hence, there are regional photocathode differences in the anode signal, which affect the decoding characteristics of position sensitive block detectors. This orientation effect, as well as the effect of introducing light diffusers, are studied in a block detector design (BGO) using the PMT-quadrant-sharing configuration. The PMT studied is the Philips XP-1911 (19mm diameter). Seven symmetrical and representative orientations of the four decoding PMT were investigated, as well as one asymmetric orientation. The measurements performed include block-composite pulse-height spectra and crystal decoding maps. Two orientation effects were observed: (A) distortion variation in decoding maps, and (B) decoding resolution variation. The introduction of circular plastic pieces, used as light diffusers, prove to be useful by improving the decoding of crystals on the periphery of the detector block and minimizing distortion in the decoding map. These measurements have shown optimal PMT orientations for the PMT-quadrant-sharing design, as well as for conventional block designs

  3. In situ micro-focused X-ray beam characterization with a lensless camera using a hybrid pixel detector

    International Nuclear Information System (INIS)

    Kachatkou, Anton; Marchal, Julien; Silfhout, Roelof van

    2014-01-01

    Position and size measurements of a micro-focused X-ray beam, using an X-ray beam imaging device based on a lensless camera that collects radiation scattered from a thin foil placed in the path of the beam at an oblique angle, are reported. Results of studies on micro-focused X-ray beam diagnostics using an X-ray beam imaging (XBI) instrument based on the idea of recording radiation scattered from a thin foil of a low-Z material with a lensless camera are reported. The XBI instrument captures magnified images of the scattering region within the foil as illuminated by the incident beam. These images contain information about beam size, beam position and beam intensity that is extracted during dedicated signal processing steps. In this work the use of the device with beams for which the beam size is significantly smaller than that of a single detector pixel is explored. The performance of the XBI device equipped with a state-of-the-art hybrid pixel X-ray imaging sensor is analysed. Compared with traditional methods such as slit edge or wire scanners, the XBI micro-focused beam characterization is significantly faster and does not interfere with on-going experiments. The challenges associated with measuring micrometre-sized beams are described and ways of optimizing the resolution of beam position and size measurements of the XBI instrument are discussed

  4. Dual-energy radiography of bone tissues using ZnSe-based scintielectronic detectors

    International Nuclear Information System (INIS)

    Grinyov, B.; Ryzhikov, V.; Lecoq, P.; Naydenov, S.; Opolonin, A.; Lisetskaya, E.; Galkin, S.; Shumeiko, N.

    2007-01-01

    Detectors of the scintillator-photodiode type were obtained on the basis of CsI(Tl), CdWO 4 and ZnSe(Te) crystals, and their comparative study was carried out, aiming at their use in X-ray computer tomography (CT). Because of their low afterglow level (10 ppm after 10 ms), CWO and ZnSe crystals are preferable for this application. A drawback of CWO is its lower (by 3 times) light output as compared with CsI(Tl). ZnSe has low transparence to intrinsic radiation; however, up to energies of 60-70 keV it is superior, as for the whole complex of its parameter, to materials traditionally used for CT detectors. The use of a dual-energy receiving-detecting circuit with a detector pair ZnSe/CsI or ZnSe/CdWO allows efficient distinction between muscular and bone tissues, which supports our earlier theoretical assumptions that this method could be successfully used for separate detection of materials differing in their effective atomic number Z eff and local density (e.g., calcium contents in bone densitometry)

  5. Dual-head gamma camera system for intraoperative localization of radioactive seeds

    International Nuclear Information System (INIS)

    Arsenali, B; Viergever, M A; Gilhuijs, K G A; De Jong, H W A M; Beijst, C; Dickerscheid, D B M

    2015-01-01

    Breast-conserving surgery is a standard option for the treatment of patients with early-stage breast cancer. This form of surgery may result in incomplete excision of the tumor. Iodine-125 labeled titanium seeds are currently used in clinical practice to reduce the number of incomplete excisions. It seems likely that the number of incomplete excisions can be reduced even further if intraoperative information about the location of the radioactive seed is combined with preoperative information about the extent of the tumor. This can be combined if the location of the radioactive seed is established in a world coordinate system that can be linked to the (preoperative) image coordinate system. With this in mind, we propose a radioactive seed localization system which is composed of two static ceiling-suspended gamma camera heads and two parallel-hole collimators. Physical experiments and computer simulations which mimic realistic clinical situations were performed to estimate the localization accuracy (defined as trueness and precision) of the proposed system with respect to collimator-source distance (ranging between 50 cm and 100 cm) and imaging time (ranging between 1 s and 10 s). The goal of the study was to determine whether or not a trueness of 5 mm can be achieved if a collimator-source distance of 50 cm and imaging time of 5 s are used (these specifications were defined by a group of dedicated breast cancer surgeons). The results from the experiments indicate that the location of the radioactive seed can be established with an accuracy of 1.6 mm  ±  0.6 mm if a collimator-source distance of 50 cm and imaging time of 5 s are used (these experiments were performed with a 4.5 cm thick block phantom). Furthermore, the results from the simulations indicate that a trueness of 3.2 mm or less can be achieved if a collimator-source distance of 50 cm and imaging time of 5 s are used (this trueness was achieved for all 14 breast phantoms which

  6. Evaluation of pulmonary nodules: comparison of a prototype dual crystal (LSO/NAI) dual head coincidence camera and full ring positron emission tomography (PET)

    International Nuclear Information System (INIS)

    Joshi, U.; Raijmakers, P.G.H.M.; Lingen, A. van; Comans, E.F.I.; Pijpers, R.; Teule, G.J.J.; Hoekstra, O.S.

    2005-01-01

    Purpose: To determine the concordance of a prototype dual head coincidence camera (LSO-PS) and full ring PET (BGO-PET) using 18 F-fluorodeoxyglucose (FDG) in the evaluation of pulmonary nodules (PNs). Materials and methods: Patients referred for evaluation of ≤3 PNs (≤3 cm diameter) were prospectively studied on the same day with both BGO-PET and LSO-PS. Imaging was performed at 60 and 120 min after injection of 370 MBq FDG, respectively. Images were independently interpreted by four observers with each observer blinded to the other modality for the same patient. Lesions were scored in terms of relative intensity versus background. Non-attenuation corrected (nonAC) BGO-PET was used as the reference test. Results: Forty-seven patients with 54 PNs (mean diameter 1.7 cm, S.D. 0.7) were included. Twelve nodules were in the ≤1.0 cm - 27 in the 1.1-2.0 cm - and 15 in the 2.1-3.0 cm range. Interobserver agreement was similar for both FDG imaging modalities. Using a sensitive assessment strategy with LSO-PS (≥ faint intensity deemed positive), there was a 97% (38/39, 95%CI 87-100%) concordance with BGO-PET and one false positive case with LSO-PS. Conservative reading (moderate or intense intensity deemed positive) resulted in a 92% (36/39, 95%CI 80-97%) concordance with BGO-PET, without false positives. The only lesion missed by LSO-PS using both assessment strategies involved a nodule 1.5 cm diameter that demonstrated moderate increased FDG uptake on BGO-PET. Conclusion: Depending on the test positivity criteria, LSO-PS demonstrates a high concordance (92-97%) with nonAC BGO-PET for the characterization of pulmonary nodules

  7. [Clinical application of high-pitch excretory phase images during dual-source CT urography with stellar photon detector].

    Science.gov (United States)

    Sun, Hao; Xue, Hua-dan; Jin, Zheng-yu; Wang, Xuan; Chen, Yu; He, Yong-lan; Zhang, Da-ming; Zhu, Liang; Wang, Yun; Qi, Bing; Xu, Kai; Wang, Ming

    2014-10-01

    To retrospectively evaluate the clinical feasibility of high-pitch excretory phase images during dual-source CT urography with Stellar photon detector. Totally 100 patients received dual-source CT high-pitch urinary excretory phase scanning with Stellar photon detector [80 kV, ref.92 mAs, CARE Dose 4D and CARE kV, pitch of 3.0, filter back projection reconstruction algorithm (FBP)] (group A). Another 100 patients received dual-source CT high-pitch urinary excretory phase scanning with common detector(100 kV, ref.140 mAs, CARE Dose 4D, pitch of 3.0, FBP) (group B). Quantitative measurement of CT value of urinary segments (Hounsfield units), image noise (Hounsfield units), and effective radiation dose (millisievert) were compared using independent-samples t test between two groups. Urinary system subjective opacification scores were compared using Mann-Whitney U test between two groups. There was no significant difference in subjective opacification score of intrarenal collecting system and ureters between two groups (all P>0.05). The group A images yielded significantly higher CT values of all urinary segments (all P0.05). The effective radiation dose of group A (1.1 mSv) was significantly lower than that of group B (3.79 mSv) (Ppitch low-tube-voltage during excretory phase dual-source CT urography with Stellar photon detector is feasible, with acceptable image noise and lower radiation dose.

  8. Direct detector radiography versus dual reading computed radiography: feasibility of dose reduction in chest radiography

    International Nuclear Information System (INIS)

    Gruber, Michael; Uffmann, Martin; Weber, Michael; Balassy, Csilla; Schaefer-Prokop, Cornelia; Prokop, Mathias

    2006-01-01

    The image quality of dual-reading computed radiography and dose-reduced direct radiography of the chest was compared in a clinical setting. The study group consisted of 50 patients that underwent three posteroanterior chest radiographs within minutes, one image obtained with a dual read-out computed radiography system (CR; Fuji 5501) at regular dose and two images with a flat panel direct detector unit (DR; Diagnost, Philips). The DR images were obtained with the same and with 50% of the dose used for the CR images. Images were evaluated in a blinded side-by-side comparison. Eight radiologists ranked the visually perceivable difference in image quality using a three-point scale. Then, three radiologists scored the visibility of anatomic landmarks in low and high attenuation areas and image noise. Statistical analysis was based on Friedman tests and Wilcoxon rank sum tests at a significance level of P<0.05. DR was judged superior to CR for the delineation of structures in high attenuation areas of the mediastinum even when obtained with 50% less dose (P<0.001). The visibility of most pulmonary structures was judged equivalent with both techniques, regardless of acquisition dose and speed level. Scores for image noise were lower for DR compared with CR, with the exception of DR obtained at a reduced dose. Thus, in this clinical preference study, DR was equivalent or even superior to the most modern dual read-out CR, even when obtained with 50% dose. A further dose reduction does not appear to be feasible for DR without significant loss of image quality. (orig.)

  9. The TIGER trigger processor for the CAMERA detector at COMPASS-II

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, Tobias; Buechele, Maximilian; Fischer, Horst; Gorzellik, Matthias; Grussenmeyer, Tobias; Herrmann, Florian; Joerg, Philipp; Kremser, Paul; Kunz, Tobias; Michalski, Christoph; Schopferer, Sebastian; Szameitat, Tobias [Physikalisches Institut der Universitaet Freiburg, Freiburg im Breisgau (Germany)

    2013-07-01

    In today's nuclear and high-energy physics experiments the background-induced occupancy of the detector channels can be quite high; therefore it is important to have sophisticated trigger subsystems which process the data in real-time to generate trigger objects for the global trigger decision. In this work we present a FPGA based low-latency trigger processor for the COMPASS-II experiment. TIGER is a high-performance trigger processor that was developed to fit perfectly in the GANDALF framework and extend its versatility. It is designed as a VXS module and is allocated to the central VXS switch slot, which has a direct link from every payload slot. The synchronous transfer protocol was optimized for low latencies and offers a bandwidth of up to 8 Gbit/s per link. The centerpiece of the board is a Xilinx Virtex-6 SX315T FPGA, offering vast programmable logic, embedded memory and DSP resources. It is accompanied by DDR3 memory, a COM Express CPU and a MXM GPU. Besides the VXS backplane ports, the board features two SFP+ transceivers, 32 LVDS inputs and 32 LVDS outputs to interface with the global trigger system and a Gigabit Ethernet port for configuration and monitoring.

  10. Beam test of a dual layer silicon charge detector (SCD) for the CREAM experiment

    International Nuclear Information System (INIS)

    Park, N.H.; Ahn, H.S.; Ganel, O.; Han, J.H.; Jeon, J.A.; Kim, C.H.; Kim, K.C.; Lutz, L.; Lee, M.H.; Malinin, A.; Nam, S.; Park, I.H.; Park, J.H.; Seo, E.S.; Walpole, P.; Wu, J.; Yang, J.; Yoo, J.H.; Yoon, Y.S.; Zinn, S.Y.

    2007-01-01

    The Cosmic Ray Energetics and Mass (CREAM) balloon-borne experiment is designed for direct measurement of high-energy cosmic rays. The experimental goal is to measure single-element fluxes of all cosmic-ray nuclei from hydrogen to iron with energies up to the 'knee', or spectral index change near 10 15 eV, observed in the all-particle spectrum. The dual layer Silicon Charge Detector (SCD) was designed to provide precise charge measurements. Each SCD layer has an active area of 77.9cmx79.5cm and consists of 156 silicon sensors mounted on 24 ladders. Each sensor contains a 4 x 4 array of single-sided DC type silicon pixels with an active area of 2.1cm 2 . The detector was flown on the second CREAM flight (December 2005-January 2006) and recovered successfully. The SCD was refurbished for the third CREAM flight and tested with high-energy electron and hadron beams at CERN. This paper reports on the performance of the SCD during the beam test

  11. Electronics for a prototype variable field of view PET camera using the PMT-quadrant-sharing detector array

    Science.gov (United States)

    Li, H.; Wong, Wai-Hoi; Zhang, N.; Wang, J.; Uribe, J.; Baghaei, H.; Yokoyama, S.

    1999-06-01

    Electronics for a prototype high-resolution PET camera with eight position-sensitive detector modules has been developed. Each module has 16 BGO (Bi/sub 4/Ge/sub 3/O/sub 12/) blocks (each block is composed of 49 crystals). The design goals are component and space reduction. The electronics is composed of five parts: front-end analog processing, digital position decoding, fast timing, coincidence processing and master data acquisition. The front-end analog circuit is a zone-based structure (each zone has 3/spl times/3 PMTs). Nine ADCs digitize integration signals of an active zone identified by eight trigger clusters; each cluster is composed of six photomultiplier tubes (PMTs). A trigger corresponding to a gamma ray is sent to a fast timing board to obtain a time-mark, and the nine digitized signals are passed to the position decoding board, where a real block (four PMTs) can be picked out from the zone for position decoding. Lookup tables are used for energy discrimination and to identify the gamma-hit crystal location. The coincidence board opens a 70-ns initial timing window, followed by two 20-ns true/accidental time-mark lookup table windows. The data output from the coincidence board can be acquired either in sinogram mode or in list mode with a Motorola/IRONICS VME-based system.

  12. A high count rate position decoding and energy measuring method for nuclear cameras using Anger logic detectors

    International Nuclear Information System (INIS)

    Wong, W.H.; Li, H.; Uribe, J.

    1998-01-01

    A new method for processing signals from Anger position-sensitive detectors used in gamma cameras and PET is proposed for very high count-rate imaging where multiple-event pileups are the norm. This method is designed to sort out and recover every impinging event from multiple-event pileups while maximizing the collection of scintillation signal for every event to achieve optimal accuracy in the measurement of energy and position. For every detected event, this method cancels the remnant signals from previous events, and excludes the pileup of signals from following events. The remnant subtraction is exact even for multiple pileup events. A prototype circuit for energy recovery demonstrated that the maximum count rates can be increased by more than 10 times comparing to the pulse-shaping method, and the energy resolution is as good as pulse shaping (or fixed integration) at low count rates. At 2 x 10 6 events/sec on NaI(Tl), the true counts acquired with this method is 3.3 times more than the delay-line clipping method (256 ns clipping) due to events recovered from pileups. Pulse-height spectra up to 3.5 x 10 6 events/sec have been studied. Monte Carlo simulation studies have been performed for image-quality comparisons between different processing methods

  13. Graphical user interface for a dual-module EMCCD x-ray detector array

    Science.gov (United States)

    Wang, Weiyuan; Ionita, Ciprian; Kuhls-Gilcrist, Andrew; Huang, Ying; Qu, Bin; Gupta, Sandesh K.; Bednarek, Daniel R.; Rudin, Stephen

    2011-03-01

    A new Graphical User Interface (GUI) was developed using Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) for a high-resolution, high-sensitivity Solid State X-ray Image Intensifier (SSXII), which is a new x-ray detector for radiographic and fluoroscopic imaging, consisting of an array of Electron-Multiplying CCDs (EMCCDs) each having a variable on-chip electron-multiplication gain of up to 2000x to reduce the effect of readout noise. To enlarge the field-of-view (FOV), each EMCCD sensor is coupled to an x-ray phosphor through a fiberoptic taper. Two EMCCD camera modules are used in our prototype to form a computer-controlled array; however, larger arrays are under development. The new GUI provides patient registration, EMCCD module control, image acquisition, and patient image review. Images from the array are stitched into a 2kx1k pixel image that can be acquired and saved at a rate of 17 Hz (faster with pixel binning). When reviewing the patient's data, the operator can select images from the patient's directory tree listed by the GUI and cycle through the images using a slider bar. Commonly used camera parameters including exposure time, trigger mode, and individual EMCCD gain can be easily adjusted using the GUI. The GUI is designed to accommodate expansion of the EMCCD array to even larger FOVs with more modules. The high-resolution, high-sensitivity EMCCD modular-array SSXII imager with the new user-friendly GUI should enable angiographers and interventionalists to visualize smaller vessels and endovascular devices, helping them to make more accurate diagnoses and to perform more precise image-guided interventions.

  14. Graphical User Interface for a Dual-Module EMCCD X-ray Detector Array.

    Science.gov (United States)

    Wang, Weiyuan; Ionita, Ciprian; Kuhls-Gilcrist, Andrew; Huang, Ying; Qu, Bin; Gupta, Sandesh K; Bednarek, Daniel R; Rudin, Stephen

    2011-03-16

    A new Graphical User Interface (GUI) was developed using Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) for a high-resolution, high-sensitivity Solid State X-ray Image Intensifier (SSXII), which is a new x-ray detector for radiographic and fluoroscopic imaging, consisting of an array of Electron-Multiplying CCDs (EMCCDs) each having a variable on-chip electron-multiplication gain of up to 2000× to reduce the effect of readout noise. To enlarge the field-of-view (FOV), each EMCCD sensor is coupled to an x-ray phosphor through a fiberoptic taper. Two EMCCD camera modules are used in our prototype to form a computer-controlled array; however, larger arrays are under development. The new GUI provides patient registration, EMCCD module control, image acquisition, and patient image review. Images from the array are stitched into a 2k×1k pixel image that can be acquired and saved at a rate of 17 Hz (faster with pixel binning). When reviewing the patient's data, the operator can select images from the patient's directory tree listed by the GUI and cycle through the images using a slider bar. Commonly used camera parameters including exposure time, trigger mode, and individual EMCCD gain can be easily adjusted using the GUI. The GUI is designed to accommodate expansion of the EMCCD array to even larger FOVs with more modules. The high-resolution, high-sensitivity EMCCD modular-array SSXII imager with the new user-friendly GUI should enable angiographers and interventionalists to visualize smaller vessels and endovascular devices, helping them to make more accurate diagnoses and to perform more precise image-guided interventions.

  15. VUV testing of science cameras at MSFC: QE measurement of the CLASP flight cameras

    Science.gov (United States)

    Champey, P.; Kobayashi, K.; Winebarger, A.; Cirtain, J.; Hyde, D.; Robertson, B.; Beabout, B.; Beabout, D.; Stewart, M.

    2015-08-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras were built and tested for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint MSFC, National Astronomical Observatory of Japan (NAOJ), Instituto de Astrofisica de Canarias (IAC) and Institut D'Astrophysique Spatiale (IAS) sounding rocket mission. The CLASP camera design includes a frame-transfer e2v CCD57-10 512 × 512 detector, dual channel analog readout and an internally mounted cold block. At the flight CCD temperature of -20C, the CLASP cameras exceeded the low-noise performance requirements (UV, EUV and X-ray science cameras at MSFC.

  16. Research on multi-spectrum detector in high-energy dual-energy X-ray imaging system

    International Nuclear Information System (INIS)

    Li Qinghua; Wang Xuewu; Li Jianmin; Kang Kejun; Li Yuanjing; Zhong Huaqiang

    2008-01-01

    The high-energy dual-energy X-ray imaging system can discriminate the material of the objects inspected, but when the objects are too thin, the discrimination becomes very difficult. This paper proposes the use of multi-spectrum detector to improve the ability to discriminate thin material, and a series of simulation were done with the Monte Carlo method. Firstly the X-ray depositions in the detectors with different thickness were calculated, and then the discrimination effects with different detector structure and parameters were calculated. The simulation results validated that using appropriate multi-spectrum detector can improve the discrimination accuracy of thin material, particularly thin high-Z material. (authors)

  17. Accuracy of bone mineral density quantification using dual-layer spectral detector CT: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Hamersvelt, Robbert W. van; Schilham, Arnold M.R.; Harder, Annemarie M. den; Leiner, Tim; Jong, Pim A. de; Willemink, Martin J. [University Medical Centre Utrecht, Department of Radiology, P.O. Box 85500, Utrecht (Netherlands); Engelke, Klaus [University of Erlangen-Nuernberg, Institute of Medical Physics, Erlangen (Germany); Keizer, Bart de [University Medical Centre Utrecht, Department of Nuclear Medicine, Utrecht (Netherlands); Verhaar, Harald J. [University Medical Centre Utrecht, Department of Geriatric Medicine, Utrecht (Netherlands)

    2017-10-15

    To investigate the accuracy of bone mineral density (BMD) quantification using dual-layer spectral detector CT (SDCT) at various scan protocols. Two validated anthropomorphic phantoms containing inserts of 50-200 mg/cm{sup 3} calcium hydroxyapatite (HA) were scanned using a 64-slice SDCT scanner at various acquisition protocols (120 and 140 kVp, and 50, 100 and 200 mAs). Regions of interest (ROIs) were placed in each insert and mean attenuation profiles at monochromatic energy levels (90-200 keV) were constructed. These profiles were fitted to attenuation profiles of pure HA and water to calculate HA concentrations. For comparison, one phantom was scanned using dual energy X-ray absorptiometry (DXA). At both 120 and 140 kVp, excellent correlations (R = 0.97, P < 0.001) were found between true and measured HA concentrations. Mean error for all measurements at 120 kVp was -5.6 ± 5.7 mg/cm{sup 3} (-3.6 ± 3.2%) and at 140 kVp -2.4 ± 3.7 mg/cm{sup 3} (-0.8 ± 2.8%). Mean measurement errors were smaller than 6% for all acquisition protocols. Strong linear correlations (R{sup 2} ≥ 0.970, P < 0.001) with DXA were found. SDCT allows for accurate BMD quantification and potentially opens up the possibility for osteoporosis evaluation and opportunistic screening in patients undergoing SDCT for other clinical indications. However, patient studies are needed to extend and translate our findings. (orig.)

  18. C-RED One and C-RED2: SWIR high-performance cameras using Saphira e-APD and Snake InGaAs detectors

    Science.gov (United States)

    Gach, Jean-Luc; Feautrier, Philippe; Stadler, Eric; Clop, Fabien; Lemarchand, Stephane; Carmignani, Thomas; Wanwanscappel, Yann; Boutolleau, David

    2018-02-01

    After the development of the OCAM2 EMCCD fast visible camera dedicated to advanced adaptive optics wavefront sensing, First Light Imaging moved to the SWIR fast cameras with the development of the C-RED One and the C-RED 2 cameras. First Light Imaging's C-RED One infrared camera is capable of capturing up to 3500 full frames per second with a subelectron readout noise and very low background. C-RED One is based on the last version of the SAPHIRA detector developed by Leonardo UK. This breakthrough has been made possible thanks to the use of an e-APD infrared focal plane array which is a real disruptive technology in imagery. C-RED One is an autonomous system with an integrated cooling system and a vacuum regeneration system. It operates its sensor with a wide variety of read out techniques and processes video on-board thanks to an FPGA. We will show its performances and expose its main features. In addition to this project, First Light Imaging developed an InGaAs 640x512 fast camera with unprecedented performances in terms of noise, dark and readout speed based on the SNAKE SWIR detector from Sofradir. The camera was called C-RED 2. The C-RED 2 characteristics and performances will be described. The C-RED One project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement N° 673944. The C-RED 2 development is supported by the "Investments for the future" program and the Provence Alpes Côte d'Azur Region, in the frame of the CPER.

  19. Quantifying metal artefact reduction using virtual monochromatic dual-layer detector spectral CT imaging in unilateral and bilateral total hip prostheses

    NARCIS (Netherlands)

    Wellenberg, R. H. H.; Boomsma, M. F.; van Osch, J. A. C.; Vlassenbroek, A.; Milles, J.; Edens, M. A.; Streekstra, G. J.; Slump, C. H.; Maas, M.

    2017-01-01

    To quantify the impact of prosthesis material and design on the reduction of metal artefacts in total hip arthroplasties using virtual monochromatic dual-layer detector Spectral CT imaging. The water-filled total hip arthroplasty phantom was scanned on a novel 128-slice Philips IQon dual-layer

  20. Characterisation of Low Frequency Gravitational Waves from Dual RF Coaxial-Cable Detector: Fractal Textured Dynamical 3-Space

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2012-07-01

    Full Text Available Experiments have revealed that the Fresnel drag effect is not present in RF coaxial cables, contrary to a previous report. This enables a very sensitive, robust and compact detector, that is 1st order in v / c and using one clock, to detect the dynamical space passing the earth, revealing the sidereal rotation of the earth, together with significant wave / turbulence e ff ects. These are “gravitational waves”, and previously detected by Cahill 2006, using an Optical-Fibre – RF Coaxial Cable Detector, and Cahill 2009, using a preliminary version of the Dual RF Coaxial Cable Detector. The gravitational waves have a 1 / f spectrum, implying a fractal structure to the textured dynamical 3- space.

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

    International Nuclear Information System (INIS)

    Deshpande, Shrikant; McNamara, Aimee L.; Holloway, Lois; Metcalfe, Peter; Vial, Philip

    2015-01-01

    Purpose: To test the feasibility of a dual detector concept for comprehensive verification of external beam radiotherapy. Specifically, the authors test the hypothesis that a portal imaging device coupled to a 2D dosimeter provides a system capable of simultaneous imaging and dose verification, and that the presence of each device does not significantly detract from the performance of the other. Methods: The dual detector configuration comprised of a standard radiotherapy electronic portal imaging device (EPID) positioned directly on top of an ionization-chamber array (ICA) with 2 cm solid water buildup material (between EPID and ICA) and 5 cm solid backscatter material. The dose response characteristics of the ICA and the imaging performance of the EPID in the dual detector configuration were compared to the performance in their respective reference clinical configurations. The reference clinical configurations were 6 cm solid water buildup material, an ICA, and 5 cm solid water backscatter material as the reference dosimetry configuration, and an EPID with no additional buildup or solid backscatter material as the reference imaging configuration. The dose response of the ICA was evaluated by measuring the detector’s response with respect to off-axis position, field size, and transit object thickness. Clinical dosimetry performance was evaluated by measuring a range of clinical intensity-modulated radiation therapy (IMRT) beams in transit and nontransit geometries. The imaging performance of the EPID was evaluated quantitatively by measuring the contrast-to-noise ratio (CNR) and spatial resolution. Images of an anthropomorphic phantom were also used for qualitative assessment. Results: The measured off-axis and field size response with the ICA in both transit and nontransit geometries for both dual detector configuration and reference dosimetry configuration agreed to within 1%. Transit dose response as a function of object thickness agreed to within 0.5%. All

  2. Large arrays of dual-polarized multichroic TES detectors for CMB measurements with the SPT-3G receiver

    Science.gov (United States)

    Posada, Chrystian M.; Ade, Peter A. R.; Anderson, Adam J.; Avva, Jessica; Ahmed, Zeeshan; Arnold, Kam S.; Austermann, Jason; Bender, Amy N.; Benson, Bradford A.; Bleem, Lindsey; Byrum, Karen; Carlstrom, John E.; Carter, Faustin W.; Chang, Clarence; Cho, Hsiao-Mei; Cukierman, Ari; Czaplewski, David A.; Ding, Junjia; Divan, Ralu N. S.; de Haan, Tijmen; Dobbs, Matt; Dutcher, Daniel; Everett, Wenderline; Gannon, Renae N.; Guyser, Robert J.; Halverson, Nils W.; Harrington, Nicholas L.; Hattori, Kaori; Henning, Jason W.; Hilton, Gene C.; Holzapfel, William L.; Huang, Nicholas; Irwin, Kent D.; Jeong, Oliver; Khaire, Trupti; Korman, Milo; Kubik, Donna L.; Kuo, Chao-Lin; Lee, Adrian T.; Leitch, Erik M.; Lendinez Escudero, Sergi; Meyer, Stephan S.; Miller, Christina S.; Montgomery, Joshua; Nadolski, Andrew; Natoli, Tyler J.; Nguyen, Hogan; Novosad, Valentyn; Padin, Stephen; Pan, Zhaodi; Pearson, John E.; Rahlin, Alexandra; Reichardt, Christian L.; Ruhl, John E.; Saliwanchik, Benjamin; Shirley, Ian; Sayre, James T.; Shariff, Jamil A.; Shirokoff, Erik D.; Stan, Liliana; Stark, Antony A.; Sobrin, Joshua; Story, Kyle; Suzuki, Aritoki; Tang, Qing Yang; Thakur, Ritoban B.; Thompson, Keith L.; Tucker, Carole E.; Vanderlinde, Keith; Vieira, Joaquin D.; Wang, Gensheng; Whitehorn, Nathan; Yefremenko, Volodymyr; Yoon, Ki Won

    2016-07-01

    Detectors for cosmic microwave background (CMB) experiments are now essentially background limited, so a straightforward alternative to improve sensitivity is to increase the number of detectors. Large arrays of multichroic pixels constitute an economical approach to increasing the number of detectors within a given focal plane area. Here, we present the fabrication of large arrays of dual-polarized multichroic transition-edge-sensor (TES) bolometers for the South Pole Telescope third-generation CMB receiver (SPT-3G). The complete SPT-3G receiver will have 2690 pixels, each with six detectors, allowing for individual measurement of three spectral bands (centered at 95 GHz, 150 GHz and 220 GHz) in two orthogonal polarizations. In total, the SPT-3G focal plane will have 16140 detectors. Each pixel is comprised of a broad-band sinuous antenna coupled to a niobium microstrip transmission line. In-line filters are used to define the different band-passes before the millimeter-wavelength signal is fed to the respective Ti/Au TES sensors. Detectors are read out using a 64x frequency domain multiplexing (fMux) scheme. The microfabrication of the SPT-3G detector arrays involves a total of 18 processes, including 13 lithography steps. Together with the fabrication process, the effect of processing on the Ti/Au TES's Tc is discussed. In addition, detectors fabricated with Ti/Au TES films with Tc between 400 mK 560 mK are presented and their thermal characteristics are evaluated. Optical characterization of the arrays is presented as well, indicating that the response of the detectors is in good agreement with the design values for all three spectral bands (95 GHz, 150 GHz, and 220 GHz). The measured optical efficiency of the detectors is between 0.3 and 0.8. Results discussed here are extracted from a batch of research of development wafers used to develop the baseline process for the fabrication of the arrays of detectors to be deployed with the SPT-3G receiver. Results from

  3. Determination of kidney function with 99mTc-DTPA renography using a dual-head camera

    DEFF Research Database (Denmark)

    Madsen, Claus J; Møller, Michael L; Zerahn, Bo

    2013-01-01

    Single-head gamma camera renography has been used for decades to estimate kidney function. An estimate of the glomerular filtration rate (GFR) can be obtained using Tc-diethylenetriaminepentaacetic acid (Tc-DTPA). However, because of differing attenuation, an error is introduced when the kidney...

  4. Whole body dual X-ray absorptiometry for bone mineral density and body composition using a flat panel detector

    International Nuclear Information System (INIS)

    Dinten, J.M.; Robert-Coutant, C.; Gonon, G.; Bordy, T.

    2003-01-01

    Whole-body dual-energy X-ray absorptiometry (DXA) systems are used for the determination of bone mineral density (BMD) but also for body composition estimates (lean mass and fat mass). The calculation is based on the difference in attenuation of body tissues for a low-energy of about 50 KeV and a high-energy of about 80-100 KeV. The measurement of dual-energy projections allows first to compute to the body composition in the non-bone area, and then to extrapolate the fat / lean ratio of soft tissue into the bone area in order to compute the BMD. Since detectors have limited area, a whole body examination requires a scan of the patient and a reconstruction process in order to build up a large field image from smaller radiographs. This reconstruction process must keep the quantitative value of the radiographs, and avoid any distortion which could be a consequence of the conic acquisition geometry. The cone angle is low (6 at maximum) and the large overlap between radiographs helps to reconstruct an image equivalent with a parallel-beam geometry. Scatter is corrected from the radiographs before reconstruction, as described in a previous paper ('Dual-energy X-rays absorptiometry using a 2D digital radiography detector. Application to bone densitometry', SPIE Medical Imaging 2001, Medical Physics). We have developed an original reconstruction method dedicated to whole-body examinations which will be described. Thanks to the quasi-radiologic quality of the detector, reconstructed images are of very good quality and this makes the measurement of BMD and fat / lean masses easier. (author)

  5. Initial clinical experience with dedicated ultra fast solid state cardiac gamma camera

    International Nuclear Information System (INIS)

    Aland, Nusrat; Lele, V.

    2010-01-01

    Full text: To analyze the imaging and diagnostic performance of new dedicated ultra fast solid state detector gamma camera and compare it with standard dual detector gamma camera in myocardial perfusion imaging. Material and Methods: In total 900 patients underwent myocardial perfusion imaging between 1st February 2010 and 29th August 2010 either stress/rest or rest/stress protocol. There was no age or gender bias (there were 630 males and 270 females). 5 and 15 mCi of 99m Tc - Tetrofosmin/MIBI was injected for 1st and 2nd part of the study respectively. Waiting period after injection was 20 min for regular stress and 40 min for pharmacological stress and 40 min after rest injection. Acquisition was performed on solid state detector gamma camera for a duration of 5 min and 3 min for 1st and 2nd part respectively. Interpretation of myocardial perfusion was done and QGS/QPS protocol was used for EF analysis. Out of these, 20 random patients underwent back to back myocardial perfusion SPECT imaging on standard dual detector gamma camera on same day. There was no age or gender bias (there were 9 males, 11 females). Acquisition time was 20 min for each part of the study. Interpretation was done using Autocard and EF analyses with 4 DM SPECT. Images obtained were then compared with those of solid state detector gamma camera. Result: Good quality and high count myocardial perfusion images were obtained with lesser amount of tracer activity on solid state detector gamma camera. Obese patients also showed good quality images with less tracer activity. As compared to conventional dual detector gamma camera images were brighter and showed better contrast with solid state gamma camera. Right ventricular imaging was better seen. Analyses of diastolic dysfunction was possible with 16 frame gated studies with solid state gamma camera. Shorter acquisition time with comfortable position reduced possibility of patient motion. All cardiac views were obtained with no movement of the

  6. A novel method to calibrate DOI function of a PET detector with a dual-ended-scintillator readout

    International Nuclear Information System (INIS)

    Shao Yiping; Yao Rutao; Ma Tianyu

    2008-01-01

    The detection of depth-of-interaction (DOI) is a critical detector capability to improve the PET spatial resolution uniformity across the field-of-view and will significantly enhance, in particular, small bore system performance for brain, breast, and small animal imaging. One promising technique of DOI detection is to use dual-ended-scintillator readout that uses two photon sensors to detect scintillation light from both ends of a scintillator array and estimate DOI based on the ratio of signals (similar to Anger logic). This approach needs a careful DOI function calibration to establish accurate relationship between DOI and signal ratios, and to recalibrate if the detection condition is shifted due to the drift of sensor gain, bias variations, or degraded optical coupling, etc. However, the current calibration method that uses coincident events to locate interaction positions inside a single scintillator crystal has severe drawbacks, such as complicated setup, long and repetitive measurements, and being prone to errors from various possible misalignments among the source and detector components. This method is also not practically suitable to calibrate multiple DOI functions of a crystal array. To solve these problems, a new method has been developed that requires only a uniform flood source to irradiate a crystal array without the need to locate the interaction positions, and calculates DOI functions based solely on the uniform probability distribution of interactions over DOI positions without knowledge or assumption of detector responses. Simulation and experiment have been studied to validate the new method, and the results show that the new method, with a simple setup and one single measurement, can provide consistent and accurate DOI functions for the entire array of multiple scintillator crystals. This will enable an accurate, simple, and practical DOI function calibration for the PET detectors based on the design of dual-ended-scintillator readout. In

  7. Calibration model of a dual gain flat panel detector for 2D and 3D x-ray imaging

    International Nuclear Information System (INIS)

    Schmidgunst, C.; Ritter, D.; Lang, E.

    2007-01-01

    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

  8. Single-layer and dual-layer contrast-enhanced mammography using amorphous selenium flat panel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Allec, N; Abbaszadeh, S; Karim, K S, E-mail: nallec@uwaterloo.ca [Department of Electrical and Computer Engineering, University of Waterloo, 200 University Avenue West, Waterloo N2L 3G1 (Canada)

    2011-09-21

    The accumulation of injected contrast agents allows the image enhancement of lesions through the use of contrast-enhanced mammography. In this technique, the combination of two acquired images is used to create an enhanced image. There exist several methods to acquire the images to be combined, which include dual energy subtraction using a single detection layer that suffers from motion artifacts due to patient motion between image acquisition. To mitigate motion artifacts, a detector composed of two layers may be used to simultaneously acquire the low and high energy images. In this work, we evaluate both of these methods using amorphous selenium as the detection material to find the system parameters (tube voltage, filtration, photoconductor thickness and relative intensity ratio) leading to the optimal performance. We then compare the performance of the two detectors under the variation of contrast agent concentration, tumor size and dose. The detectability was found to be most comparable at the lower end of the evaluated factors. The single-layer detector not only led to better contrast, due to its greater spectral separation capabilities, but also had lower quantum noise. The single-layer detector was found to have a greater detectability by a factor of 2.4 for a 2.5 mm radius tumor having a contrast agent concentration of 1.5 mg ml{sup -1} in a 4.5 cm thick 50% glandular breast. The inclusion of motion artifacts in the comparison is part of ongoing research efforts.

  9. Single-layer and dual-layer contrast-enhanced mammography using amorphous selenium flat panel detectors

    Science.gov (United States)

    Allec, N.; Abbaszadeh, S.; Karim, K. S.

    2011-09-01

    The accumulation of injected contrast agents allows the image enhancement of lesions through the use of contrast-enhanced mammography. In this technique, the combination of two acquired images is used to create an enhanced image. There exist several methods to acquire the images to be combined, which include dual energy subtraction using a single detection layer that suffers from motion artifacts due to patient motion between image acquisition. To mitigate motion artifacts, a detector composed of two layers may be used to simultaneously acquire the low and high energy images. In this work, we evaluate both of these methods using amorphous selenium as the detection material to find the system parameters (tube voltage, filtration, photoconductor thickness and relative intensity ratio) leading to the optimal performance. We then compare the performance of the two detectors under the variation of contrast agent concentration, tumor size and dose. The detectability was found to be most comparable at the lower end of the evaluated factors. The single-layer detector not only led to better contrast, due to its greater spectral separation capabilities, but also had lower quantum noise. The single-layer detector was found to have a greater detectability by a factor of 2.4 for a 2.5 mm radius tumor having a contrast agent concentration of 1.5 mg ml-1 in a 4.5 cm thick 50% glandular breast. The inclusion of motion artifacts in the comparison is part of ongoing research efforts.

  10. Dual detector pulsed neutron logging for providing indication of formation porosity

    International Nuclear Information System (INIS)

    Hopkinson, E.C.

    1979-01-01

    A logging instrument contains a pulsed neutron source and a pair of radiation detectors spaced along the length of the instrument. The radiation detectors are gated differently from each other to provide an indication of formation porosity which is substantially independent of the formation salinity. In the preferred embodiment, the electrical signals indicative of radiation detected by the long-spaced detector are gated for almost the entire interval between neutron pulses and the short-spaced signals are gated for a significantly smaller time interval which commences soon after the termination of a given neutron burst. The signals from the two detectors are combined in a ratio circuit for determination of porosity

  11. Dual-Energy Semiconductor Detector of X-rays and Gamma Radiation

    Directory of Open Access Journals (Sweden)

    Brodyn, M.S.

    2014-03-01

    Full Text Available Analysis of the major types of ionizing radiation detectors, their advantages and disadvantages are presented. Application of ZnSe-based semiconductor detector in high temperature environment is substantiated. Different forms of ZnSe-based detector samples and double-crystal scheme for registration of X- and gamma rays in a broad energy range were used . Based on the manufactured simulator device, the study sustains the feasibility of the gamma quanta recording by a high-resistance ZnSe-based detector operating in a perpulse mode.

  12. Initial tests of the dual-sweep streak camera system planned for APS particle-beam diagnostics

    International Nuclear Information System (INIS)

    Lumpkin, A.; Yang, B.; Gai, W.; Cieslik, W.

    1995-01-01

    Initial tests of a dual-sweep streak system planned for use on the Advanced Photon Source (APS) have been performed using assets of the Argonne Wakefield Accelerator (AWA) facility. The short light pulses from the photoelectric injector drive laser in both the visible (λ=496 nm, Δt∼1.5 ps (FWHM)), and the ultraviolet (λ=248 nm, Δt∼5 ps (FWHM)) were used. Both a UV-visible S20 photocathode streak tube and a UV-to-x-ray Au photocathode streak tube were tested. Calibration data with an etalon were also obtained. A sample of dual-sweep streak data using optical synchrotron radiation on the APS injector synchrotron is also presented

  13. Spectrophotometric flow-injection analysis assay of tetracycline antibiotics using a dual light-emitting diode based detector

    Directory of Open Access Journals (Sweden)

    Prinya Masawat

    2008-02-01

    Full Text Available In this paper, a small dual light-emitting diode (LED-based detector for FIA process analyser has been designed. The detector’s optical parts comprise a flow-through cell, a dual-blue LED and a photodiode. Neither mirrors nor lenses are used. The optical path for the first LED detects the blank, while the other LED detects the sample. The detector’s electronic components including a signal amplifier and an A/D converter are integrated on one small board connected to a PC for measuring the results. The designed spectrophotometric detector was used for the determination of tetracycline antibiotics. Uranyl acetate was used as a reagent forming orange-red complexes with the drugs in N,N– dimethylformamide. The complexes show absorption maxima at 410, 416 and 408 nm for tetracycline hydrochloride (TCH, chlortetracycline hydrochloride (CTCH, and doxycycline hydrochloride (DCH, respectively. The detection limit was found to be 0.38, 0.75, 1.44 µg mL-1 and the linear range was obtained at 1.0-3.0, 3.0-5.0, and 3.0-10.0 µg mL-1 for TCH, CTCH and DCH, respectively. The proposed method has been successfully applied to the determination of tetracycline antibiotic residues in milk samples. Moreover, this method is an environmentally friendly approach and suitable for routine analysis.

  14. Shot-Noise-Limited Dual-Beam Detector for Atmospheric Trace-Gas Monitoring with Near-Infrared Diode Lasers

    Science.gov (United States)

    Durry, Georges; Pouchet, Ivan; Amarouche, Nadir; Danguy, Théodore; Megie, Gerard

    2000-10-01

    A dual-beam detector is used to measure atmospheric trace species by differential absorption spectroscopy with commercial near-infrared InGaAs laser diodes. It is implemented on the Spectrom tre Diodes Laser Accordables, a balloonborne tunable diode laser spectrometer devoted to the in situ monitoring of CH 4 and H 2 O. The dual-beam detector is made of simple analogical subtractor circuits combined with InGaAs photodiodes. The detection strategy consists in taking the balanced analogical difference between the reference and the sample signals detected at the input and the output of an open optical multipass cell to apply the full dynamic range of the measurements (16 digits) to the weak molecular absorption information. The obtained sensitivity approaches the shot-noise limit. With a 56-m optical cell, the detection limit obtained when the spectra is recorded within 8 ms is 10 4 (expressed in absorbance units). The design and performances of both a simple substractor and an upgraded feedback substractor circuit are discussed with regard to atmospheric in situ CH 4 absorption spectra measured in the 1.653- m region. Mixing ratios are obtained from the absorption spectra by application of a nonlinear least-squares fit to the full molecular line shape in conjunction with in situ P and T measurements.

  15. Dose optimization for dual-energy contrast-enhanced digital mammography based on an energy-resolved photon-counting detector: A Monte Carlo simulation study

    Science.gov (United States)

    Lee, Youngjin; Lee, Seungwan; Kang, Sooncheol; Eom, Jisoo

    2017-03-01

    Dual-energy contrast-enhanced digital mammography (CEDM) has been used to decompose breast images and improve diagnostic accuracy for tumor detection. However, this technique causes an increase of radiation dose and an inaccuracy in material decomposition due to the limitations of conventional X-ray detectors. In this study, we simulated the dual-energy CEDM with an energy-resolved photon-counting detector (ERPCD) for reducing radiation dose and improving the quantitative accuracy of material decomposition images. The ERPCD-based dual-energy CEDM was compared to the conventional dual-energy CEDM in terms of radiation dose and quantitative accuracy. The correlation between radiation dose and image quality was also evaluated for optimizing the ERPCD-based dual-energy CEDM technique. The results showed that the material decomposition errors of the ERPCD-based dual-energy CEDM were 0.56-0.67 times lower than those of the conventional dual-energy CEDM. The imaging performance of the proposed technique was optimized at the radiation dose of 1.09 mGy, which is a half of the MGD for a single view mammogram. It can be concluded that the ERPCD-based dual-energy CEDM with an optimal exposure level is able to improve the quality of material decomposition images as well as reduce radiation dose.

  16. Feasibility and accuracy of dual-layer spectral detector computed tomography for quantification of gadolinium: a phantom study.

    Science.gov (United States)

    van Hamersvelt, Robbert W; Willemink, Martin J; de Jong, Pim A; Milles, Julien; Vlassenbroek, Alain; Schilham, Arnold M R; Leiner, Tim

    2017-09-01

    The aim of this study was to evaluate the feasibility and accuracy of dual-layer spectral detector CT (SDCT) for the quantification of clinically encountered gadolinium concentrations. The cardiac chamber of an anthropomorphic thoracic phantom was equipped with 14 tubular inserts containing different gadolinium concentrations, ranging from 0 to 26.3 mg/mL (0.0, 0.1, 0.2, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0, 5.1, 10.6, 15.7, 20.7 and 26.3 mg/mL). Images were acquired using a novel 64-detector row SDCT system at 120 and 140 kVp. Acquisitions were repeated five times to assess reproducibility. Regions of interest (ROIs) were drawn on three slices per insert. A spectral plot was extracted for every ROI and mean attenuation profiles were fitted to known attenuation profiles of water and pure gadolinium using in-house-developed software to calculate gadolinium concentrations. At both 120 and 140 kVp, excellent correlations between scan repetitions and true and measured gadolinium concentrations were found (R > 0.99, P  0.99, CI 0.99-1.00). Relative mean measurement errors stayed below 10% down to 2.0 mg/mL true gadolinium concentration at 120 kVp and below 5% down to 1.0 mg/mL true gadolinium concentration at 140 kVp. SDCT allows for accurate quantification of gadolinium at both 120 and 140 kVp. Lowest measurement errors were found for 140 kVp acquisitions. • Gadolinium quantification may be useful in patients with contraindication to iodine. • Dual-layer spectral detector CT allows for overall accurate quantification of gadolinium. • Interscan variability of gadolinium quantification using SDCT material decomposition is excellent.

  17. Dual germanium detector system for the routine assay of low level transuranics in soil

    International Nuclear Information System (INIS)

    Crowell, J.M.

    1980-01-01

    As an outgrowth of previous on soil radioassay, we have developed an automated assay system for determining the transuranic radionuclide content of soils, with particular interest in Pu. The system utilizes two commercial planar intrinsic germanium detectors in opposition. The large area of the detectors (2100 mm 2 ) and the thinness of the detector crystals (7 mm) permit sensitive analysis of the L x ray emission region of the transuranics (13 to 21 keV). With counting times of 5 hours, we obtain detection limits of 241 Am

  18. The GCT camera for the Cherenkov Telescope Array

    Science.gov (United States)

    Lapington, J. S.; Abchiche, A.; Allan, D.; Amans, J.-P.; Armstrong, T. P.; Balzer, A.; Berge, D.; Boisson, C.; Bousquet, J.-J.; Bose, R.; Brown, A. M.; Bryan, M.; Buchholtz, G.; Buckley, J.; Chadwick, P. M.; Costantini, H.; Cotter, G.; Daniel, M. K.; De Franco, A.; De Frondat, F.; Dournaux, J.-L.; Dumas, D.; Ernenwein, J.-P.; Fasola, G.; Funk, S.; Gironnet, J.; Graham, J. A.; Greenshaw, T.; Hervet, O.; Hidaka, N.; Hinton, J. A.; Huet, J.-M.; Jankowsky, D.; Jegouzo, I.; Jogler, T.; Kawashima, T.; Kraus, M.; Laporte, P.; Leach, S.; Lefaucheur, J.; Markoff, S.; Melse, T.; Minaya, I. A.; Mohrmann, L.; Molyneux, P.; Moore, P.; Nolan, S. J.; Okumura, A.; Osborne, J. P.; Parsons, R. D.; Rosen, S.; Ross, D.; Rowell, G.; Rulten, C. B.; Sato, Y.; Sayede, F.; Schmoll, J.; Schoorlemmer, H.; Servillat, M.; Sol, H.; Stamatescu, V.; Stephan, M.; Stuik, R.; Sykes, J.; Tajima, H.; Thornhill, J.; Tibaldo, L.; Trichard, C.; Varner, G.; Vink, J.; Watson, J. J.; White, R.; Yamane, N.; Zech, A.; Zink, A.; Zorn, J.; CTA Consortium

    2017-12-01

    The Gamma Cherenkov Telescope (GCT) is one of the designs proposed for the Small Sized Telescope (SST) section of the Cherenkov Telescope Array (CTA). The GCT uses dual-mirror optics, resulting in a compact telescope with good image quality and a large field of view with a smaller, more economical, camera than is achievable with conventional single mirror solutions. The photon counting GCT camera is designed to record the flashes of atmospheric Cherenkov light from gamma and cosmic ray initiated cascades, which last only a few tens of nanoseconds. The GCT optics require that the camera detectors follow a convex surface with a radius of curvature of 1 m and a diameter of 35 cm, which is approximated by tiling the focal plane with 32 modules. The first camera prototype is equipped with multi-anode photomultipliers, each comprising an 8×8 array of 6×6 mm2 pixels to provide the required angular scale, adding up to 2048 pixels in total. Detector signals are shaped, amplified and digitised by electronics based on custom ASICs that provide digitisation at 1 GSample/s. The camera is self-triggering, retaining images where the focal plane light distribution matches predefined spatial and temporal criteria. The electronics are housed in the liquid-cooled, sealed camera enclosure. LED flashers at the corners of the focal plane provide a calibration source via reflection from the secondary mirror. The first GCT camera prototype underwent preliminary laboratory tests last year. In November 2015, the camera was installed on a prototype GCT telescope (SST-GATE) in Paris and was used to successfully record the first Cherenkov light of any CTA prototype, and the first Cherenkov light seen with such a dual-mirror optical system. A second full-camera prototype based on Silicon Photomultipliers is under construction. Up to 35 GCTs are envisaged for CTA.

  19. Dose optimization for dual-energy contrast-enhanced digital mammography based on an energy-resolved photon-counting detector: A Monte Carlo simulation study

    International Nuclear Information System (INIS)

    Lee, Youngjin; Lee, Seungwan; Kang, Sooncheol; Eom, Jisoo

    2017-01-01

    Dual-energy contrast-enhanced digital mammography (CEDM) has been used to decompose breast images and improve diagnostic accuracy for tumor detection. However, this technique causes an increase of radiation dose and an inaccuracy in material decomposition due to the limitations of conventional X-ray detectors. In this study, we simulated the dual-energy CEDM with an energy-resolved photon-counting detector (ERPCD) for reducing radiation dose and improving the quantitative accuracy of material decomposition images. The ERPCD-based dual-energy CEDM was compared to the conventional dual-energy CEDM in terms of radiation dose and quantitative accuracy. The correlation between radiation dose and image quality was also evaluated for optimizing the ERPCD-based dual-energy CEDM technique. The results showed that the material decomposition errors of the ERPCD-based dual-energy CEDM were 0.56–0.67 times lower than those of the conventional dual-energy CEDM. The imaging performance of the proposed technique was optimized at the radiation dose of 1.09 mGy, which is a half of the MGD for a single view mammogram. It can be concluded that the ERPCD-based dual-energy CEDM with an optimal exposure level is able to improve the quality of material decomposition images as well as reduce radiation dose. - Highlights: • Dual-energy mammography based on a photon-counting detector was simulated. • Radiation dose and image quality were evaluated for optimizing the proposed technique. • The proposed technique reduced radiation dose as well as improved image quality. • The proposed technique was optimized at the radiation dose of 1.09 mGy.

  20. Gamma camera system

    International Nuclear Information System (INIS)

    Miller, D.W.; Gerber, M.S.; Schlosser, P.A.; Steidley, J.W.

    1980-01-01

    A detailed description is given of a novel gamma camera which is designed to produce superior images than conventional cameras used in nuclear medicine. The detector consists of a solid state detector (e.g. germanium) which is formed to have a plurality of discrete components to enable 2-dimensional position identification. Details of the electronic processing circuits are given and the problems and limitations introduced by noise are discussed in full. (U.K.)

  1. Development of a 32-detector CdTe matrix for the SVOM ECLAIRs X/Gamma camera: Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Lacombe, K., E-mail: karine.lacombe@irap.omp.eu [Université de Toulouse, Toulouse (France); UPS-OMP, Toulouse (France); IRAP CNRS, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France); Nasser, G.; Amoros, C.; Atteia, J.-L.; Barret, D. [Université de Toulouse, Toulouse (France); UPS-OMP, Toulouse (France); IRAP CNRS, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France); Billot, M. [CNES, 18 Av. Edouard Belin, 31 401 Toulouse Cedex 9 (France); Cordier, B.; Gevin, O. [CEA, IRFU, 91191 Gif-sur-Yvette (France); Godet, O. [Université de Toulouse, Toulouse (France); UPS-OMP, Toulouse (France); IRAP CNRS, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France); Gonzalez, F. [CNES, 18 Av. Edouard Belin, 31 401 Toulouse Cedex 9 (France); Houret, B.; Landé, J. [Université de Toulouse, Toulouse (France); UPS-OMP, Toulouse (France); IRAP CNRS, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France); Lugiez, F. [CEA, IRFU, 91191 Gif-sur-Yvette (France); Mandrou, P.; Martin, J.-A.; Marty, W. [Université de Toulouse, Toulouse (France); UPS-OMP, Toulouse (France); IRAP CNRS, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France); Mercier, K. [CNES, 18 Av. Edouard Belin, 31 401 Toulouse Cedex 9 (France); Pons, R.; Rambaud, D.; Ramon, P. [Université de Toulouse, Toulouse (France); UPS-OMP, Toulouse (France); IRAP CNRS, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France); and others

    2013-12-21

    ECLAIRs, a 2D coded-mask imaging telescope on the Sino-French SVOM space mission, will detect and locate gamma-ray bursts (GRBs) between 4 and 150 keV. The detector array is an assembly of 6400 Schottky CdTe detectors of size 4×4×1 mm{sup 3}, biased from −100 V to −600 V and operated at −20 °C to minimize the leakage current and maximize the polarization time. The remarkable low-energy threshold is achieved through various steps: an extensive detectors selection, a low-noise 32 channels ASIC study, and the design of an innovative detection module called XRDPIX formed by a thick film ceramic holding 32 detectors, a high voltage grid and an HTCC substrate housing the ASIC within a hermetic cavity. In this paper, we describe the XRDPIX module and explain the results of first tests to measure the linearity and compare the sources of noise, such as leakage currents and the Equivalent Noise Charge (ENC) measured on ASIC Ceramics. We confront these values with the energy threshold and spectral resolution made with dedicated test benches. Finally, we present the superposition of 32 calibrated spectra of one XRDPIX module, showing the excellent homogeneity of the 32 detectors and the achievement of a detection threshold at 4 keV over the entire module. -- Highlights: •We develop X and gamma rays detection modules to shape a space telescope. •The main goal of 4 keV threshold is reached thanks to a new hybrid based on CdTe. •Great spectral performance depends on low equivalent noise charge of ASIC on ceramics. •We study the good linearity of the calibration curve below the 16 keV energy. •An outgassing stage will decrease the leakage current of detectors glued on ceramics.

  2. Choice of crystal surface finishing for a dual-ended readout depth-of-interaction (DOI) detector

    International Nuclear Information System (INIS)

    Fan, Peng; Ma, Tianyu; Liu, Yaqiang; Wang, Shi; Wei, Qingyang; Yao, Rutao

    2016-01-01

    The objective of this study was to choose the crystal surface finishing for a dual-ended readout (DER) DOI detector. Through Monte Carlo simulations and experimental studies, we evaluated 4 crystal surface finishing options as combinations of crystal surface polishing (diffuse or specular) and reflector (diffuse or specular) options on a DER detector. We also tested one linear and one logarithm DOI calculation algorithm. The figures of merit used were DOI resolution, DOI positioning error, and energy resolution. Both the simulation and experimental results show that (1) choosing a diffuse type in either surface polishing or reflector would improve DOI resolution but degrade energy resolution; (2) crystal surface finishing with a diffuse polishing combined with a specular reflector appears a favorable candidate with a good balance of DOI and energy resolution; and (3) the linear and logarithm DOI calculation algorithms show overall comparable DOI error, and the linear algorithm was better for photon interactions near the ends of the crystal while the logarithm algorithm was better near the center. These results provide useful guidance in DER DOI detector design in choosing the crystal surface finishing and DOI calculation methods. (paper)

  3. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    A positron emission tomography camera having a plurality of detector rings positioned side-by-side or offset by one-half of the detector cross section around a patient area to detect radiation therefrom. Each detector ring or offset ring includes a plurality of photomultiplier tubes and a plurality of scintillation crystals are positioned relative to the photomultiplier tubes whereby each tube is responsive to more than one crystal. Each alternate crystal in the ring is offset by one-half or less of the thickness of the crystal such that the staggered crystals are seen by more than one photomultiplier tube. This sharing of crystals and photomultiplier tubes allows identification of the staggered crystal and the use of smaller detectors shared by larger photomultiplier tubes thereby requiring less photomultiplier tubes, creating more scanning slices, providing better data sampling, and reducing the cost of the camera. The offset detector ring geometry reduces the costs of the positron camera and improves its performance

  4. A preliminary feasibility study of simultaneous dual-isotope imaging with a solid-state dedicated cardiac camera for evaluating myocardial perfusion and fatty acid metabolism.

    Science.gov (United States)

    Ko, Toshiyuki; Utanohara, Yuko; Suzuki, Yasuhiro; Kurihara, Makiko; Iguchi, Nobuo; Umemura, Jun; Sumiyoshi, Tetsuya; Tomoike, Hitonobu

    2016-01-01

    Simultaneous dual-isotope SPECT imaging with 201Tl and (123)I-β-methyl-p-iodophenylpentadecanoic acid (BMIPP) is used to study the perfusion-metabolism mismatch. It predicts post-ischemic functional recovery by detecting stunned myocardium. On the other hand, (99m)Tc-MIBI is another radioisotope widely used in myocardial perfusion imaging because of its better image quality and lower radiation exposure than 201Tl. However, since the photopeak energies of (99m)Tc and (123)I are very similar, crosstalk hampers the simultaneous use of these two radioisotopes. To overcome this problem, we conducted simultaneous dual-isotope imaging study using the D-SPECT scanner (Spectrum-Dynamics, Israel) which has a novel detector design and excellent energy resolution. We first conducted a basic experiment using cardiac phantom to simulate the condition of normal perfusion and impaired fatty acid metabolism. Subsequently, we prospectively recruited 30 consecutive patients who underwent successful percutaneous coronary intervention for acute myocardial infarction, and performed (99m)Tc-MIBI/(123)I-BMIPP dual-isotope imaging within 5 days after reperfusion. Images were interpreted by two experienced cardiovascular radiologists to identify the infarcted and stunned areas based on the coronary artery territories. As a result, cardiac phantom experiment revealed no significant crosstalk between (99m)Tc and (123)I. In the subsequent clinical study, (99m)Tc-MIBI/(123)I-BMIPP dual-isotope imaging in all participant yielded excellent image quality and detected infarcted and stunned areas correctly when compared with coronary angiographic findings. Furthermore, we were able to reduce radiation exposure to significantly approximately one-eighth. In conclusion, we successfully demonstrated the practical application of simultaneous assessment of myocardial perfusion and fatty acid metabolism by (99m)Tc-MIBI and (123)I-BMIPP using a D-SPECT cardiac scanner. Compared with conventional (201)Tl

  5. Monolithic dual-band HgCdTe infrared detector structure

    CSIR Research Space (South Africa)

    Parish, G

    1997-07-01

    Full Text Available A monolithic HgCdTe photoconductive device structure is presented that is suitable for dual-band optically registered infrared photodetection in the two atmospheric transmission windows of 3-5 mu m and 8-12 mu m, which correspond to the mid...

  6. VUV Testing of Science Cameras at MSFC: QE Measurement of the CLASP Flight Cameras

    Science.gov (United States)

    Champey, Patrick R.; Kobayashi, Ken; Winebarger, A.; Cirtain, J.; Hyde, D.; Robertson, B.; Beabout, B.; Beabout, D.; Stewart, M.

    2015-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras were built and tested for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The CLASP camera design includes a frame-transfer e2v CCD57-10 512x512 detector, dual channel analog readout electronics and an internally mounted cold block. At the flight operating temperature of -20 C, the CLASP cameras achieved the low-noise performance requirements (less than or equal to 25 e- read noise and greater than or equal to 10 e-/sec/pix dark current), in addition to maintaining a stable gain of approximately equal to 2.0 e-/DN. The e2v CCD57-10 detectors were coated with Lumogen-E to improve quantum efficiency (QE) at the Lyman- wavelength. A vacuum ultra-violet (VUV) monochromator and a NIST calibrated photodiode were employed to measure the QE of each camera. Four flight-like cameras were tested in a high-vacuum chamber, which was configured to operate several tests intended to verify the QE, gain, read noise, dark current and residual non-linearity of the CCD. We present and discuss the QE measurements performed on the CLASP cameras. We also discuss the high-vacuum system outfitted for testing of UV and EUV science cameras at MSFC.

  7. Use of internal scintillator radioactivity to calibrate DOI function of a PET detector with a dual-ended-scintillator readout

    International Nuclear Information System (INIS)

    Bircher, Chad; Shao Yiping

    2012-01-01

    Purpose: Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method could be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. Methods: The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators' internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 x 1.5 and 2.0 x 2.0 mm 2 cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. Results: All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. Conclusions: The internal radioactivity of LYSO scintillators can be used to

  8. Time-lapse cased hole reservoir evaluation based on the dual-detector neutron lifetime log: the CHES II approach

    International Nuclear Information System (INIS)

    DeVries, M.R.; Fertl, W.

    1977-01-01

    A newly developed cased hole analysis technique provides detailed information on (1) reservoir rock properties, such as porosity, shaliness, and formation permeability, (2) reservoir fluid saturation, (3) distinction of oil and gas pays, (4) state of reservoir depletion, such as cumulative hydrocarbon-feet at present time and cumulative hydrocarbon-feet already depleted (e.g., the sum of both values then giving the cumulative hydrocarbon-feet originally present), and (5) monitoring of hydrocarbon/water and gas/oil contacts behind pipe. The basic well log data required for this type of analysis include the Dual-Detector Neutron Lifetime Log, run in casing at any particular time in the life of a reservoir, and the initial open-hole resistivity log. In addition, porosity information from open-hole porosity log(s) or core data is necessary. Field examples from several areas are presented and discussed in the light of formation reservoir and hydrocarbon production characteristics

  9. Dual-layer spectral detector CT: non-inferiority assessment compared to dual-source dual-energy CT in discriminating uric acid from non-uric acid renal stones ex vivo.

    Science.gov (United States)

    Ananthakrishnan, Lakshmi; Duan, Xinhui; Xi, Yin; Lewis, Matthew A; Pearle, Margaret S; Antonelli, Jodi A; Goerne, Harold; Kolitz, Elysha M; Abbara, Suhny; Lenkinski, Robert E; Fielding, Julia R; Leyendecker, John R

    2018-04-07

    To assess the non-inferiority of dual-layer spectral detector CT (SDCT) compared to dual-source dual-energy CT (dsDECT) in discriminating uric acid (UA) from non-UA stones. Fifty-seven extracted urinary calculi were placed in a cylindrical phantom in a water bath and scanned on a SDCT scanner (IQon, Philips Healthcare) and second- and third-generation dsDECT scanners (Somatom Flash and Force, Siemens Healthcare) under matched scan parameters. For SDCT data, conventional images and virtual monoenergetic reconstructions were created. A customized 3D growing region segmentation tool was used to segment each stone on a pixel-by-pixel basis for statistical analysis. Median virtual monoenergetic ratios (VMRs) of 40/200, 62/92, and 62/100 for each stone were recorded. For dsDECT data, dual-energy ratio (DER) for each stone was recorded from vendor-specific postprocessing software (Syngo Via) using the Kidney Stones Application. The clinical reference standard of X-ray diffraction analysis was used to assess non-inferiority. Area under the receiver-operating characteristic curve (AUC) was used to assess diagnostic performance of detecting UA stones. Six pure UA, 47 pure calcium-based, 1 pure cystine, and 3 mixed struvite stones were scanned. All pure UA stones were correctly separated from non-UA stones using SDCT and dsDECT (AUC = 1). For UA stones, median VMR was 0.95-0.99 and DER 1.00-1.02. For non-UA stones, median VMR was 1.4-4.1 and DER 1.39-1.69. SDCT spectral reconstructions demonstrate similar performance to those of dsDECT in discriminating UA from non-UA stones in a phantom model.

  10. Method and apparatus for logging a borehole employing dual radiation detectors

    International Nuclear Information System (INIS)

    Arnold, D.M.

    1986-01-01

    An apparatus is described for logging a characteristic of a borehole in an earth formation employing nuclear count rate data selectively compensated for non-standard borehole conditions, comprising: a sonde, movable in a borehole, having: a radiation source for emitting radiation into earth formations adjacent the wellbore; first detector, spaced longitudinally from the radiation source, for detecting radiation scattered back to the detector and generating a first signal representative of a first count rate value, C/sub SS/; and second detector spaced a different longitudinal distance from the radiation source, for detecting radiation scattered back to the detector and generating a second signal representative of a count rate value, C/sub LS/; memory means for storing a predetermined threshold value, first predetermined relationships between the borehole characteristic and count rate values C/sub LS/, C/sub SS/; and second predetermined relationships between the borehole characteristic and ratios of C/sub LS/ to C/sub SS/; electronic means for producing a signal related in value to the borehole characteristic, which electronic means compares at least one of the first and second count rate value signals with the predetermined threshold value; means for recording the signal generated by the electronic means

  11. Optimization of breast cancer detection in Dual Energy X-ray Mammography using a CMOS imaging detector

    International Nuclear Information System (INIS)

    Koukou, V; Martini, N; Sotiropoulou, P; Nikiforidis, G; Fountos, G; Michail, C; Kalyvas, N; Valais, I; Kandarakis, I; Bakas, A; Kounadi, E

    2015-01-01

    Dual energy mammography has the ability to improve the detection of microcalcifications leading to early diagnosis of breast cancer. In this simulation study, a prototype dual energy mammography system, using a CMOS based imaging detector with different X-ray spectra, was modeled. The device consists of a 33.91 mg/cm 2 Gd 2 O 2 S:Tb scintillator screen, placed in direct contact with the sensor, with a pixel size of 22.5 μm. Various filter materials and tube voltages of a Tungsten (W) anode for both the low and high energy were examined. The selection of the filters applied to W spectra was based on their K- edges (K-edge filtering). Hydroxyapatite (HAp) was used to simulate microcalcifications. Calcification signal-to-noise ratio (SNR tc ) was calculated for entrance surface dose within the acceptable levels of conventional mammography. Optimization was based on the maximization of SNR tc while minimizing the entrance dose. The best compromise between SNR tc value and dose was provided by a 35kVp X-ray spectrum with added beam filtration of 100μm Pd and a 70kVp Yb filtered spectrum of 800 μm for the low and high energy, respectively. Computer simulation results show that a SNR tc value of 3.6 can be achieved for a calcification size of 200 μm. Compared with previous studies, this method can improve detectability of microcalcifications

  12. Optimal design of detector thickness for dual-energy x-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Woon; Kim, Ho Kyung [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The projection of three-dimensional (3D) human body on a two-dimensional (2D) radiograph results in the superimposition of normal tissue that can obscure abnormalities and in some common cases be misread as abnormalities. To reduce or eliminate this effect, 3D depth-discrimination techniques such as computed tomography can be used. Another method for improving conspicuity of abnormalities is an energy discrimination technique such as dual-energy imaging (DEI). The DEI discriminates, or enhances, material content (e.g. bone or soft tissue) within a 2D radiograph by combining images obtained at separte low and high energies. A commercial DEI system uses the fast kilovoltage (kVp) switching technique, which acquires low and highkVp projections in successive x-ray exposure. To obtain better quality in DE images, a large energy separation between the low and high-kVp setups is typically used for chest (e.g. 60/120 kVp). The optimal CsI thickness for dual-energy chest imaging has been theoretically investigated by evaluating prewhitening observer model detectability indexes. To evaluate the PW and PWE detectability indexes, dual-energy fluence and MTF have reviewed compared to the conventional descriptions.

  13. Dynamic defectoscopy with flat panel and CdTe Timepix X-ray detectors combined with an optical camera

    Czech Academy of Sciences Publication Activity Database

    Vavřík, Daniel; Fauler, A.; Fiederle, M.; Jandejsek, Ivan; Jakůbek, J.; Tureček, D.; Zwerger, A.

    2013-01-01

    Roč. 8, April (2013), C04009 ISSN 1748-0221. [International Workshop on Radiation Imaging Detectors /14./. Figueira da Foz, Coimbra, 01.07.2012-05.07.2012] R&D Projects: GA ČR(CZ) GA103/09/2101 Institutional support: RVO:68378297 Keywords : X-ray digital radiography * fracture mechanics * crack path * X-ray defectoscopy Subject RIV: JM - Building Engineering Impact factor: 1.526, year: 2013 http://iopscience.iop.org/1748-0221/8/04/C04009/

  14. Potential applications of a dual-sweep streak camera system for characterizing particle and photon beams of VUV, XUV, and x-ray FELS

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. [Argonne National Lab., IL (United States)

    1995-12-31

    The success of time-resolved imaging techniques in the Characterization of particle beams and photon beams of the recent generation of L-band linac-driven or storage ring FELs in the infrared, visible, and ultraviolet wavelength regions can be extended to the VUV, XUV, and x-ray FELs. Tests and initial data have been obtained with the Hamamatsu C5680 dual-sweep streak camera system which includes a demountable photocathode (thin Au) assembly and a flange that allows windowless operation with the transport vacuum system. This system can be employed at wavelengths shorter than 100 nm and down to 1 {Angstrom}. First tests on such a system at 248-nm wavelengths have been performed oil the Argonne Wakefield Accelerator (AWA) drive laser source. A quartz window was used at the tube entrance aperture. A preliminary test using a Be window mounted on a different front flange of the streak tube to look at an x-ray bremsstrahlung source at the AWA was limited by photon statistics. This system`s limiting resolution of {sigma}{approximately}1.1 ps observed at 248 nm would increase with higher incoming photon energies to the photocathode. This effect is related to the fundamental spread in energies of the photoelectrons released from the photocathodes. Possible uses of the synchrotron radiation sources at the Advanced Photon Source and emerging short wavelength FELs to test the system will be presented.

  15. PET with a dual-head coincidence gamma camera in head and neck cancer: A comparison with computed tomography and dedicated PET

    International Nuclear Information System (INIS)

    Zimny, M.

    2001-01-01

    Positron emission tomography with 18 F-fluoro-deoxyglucose (FDG PET) is a promising imaging tool for detecting and staging of primary or recurrent head and neck cancer. The aim of this study was to evaluate a dual-head gamma camera modified for coincidence detection (KGK-PET) in comparison to computed tomography (CT) and dedicated PET (dPET). 50 patients with known or suspected primary or recurrent head and neck cancer were enrolled. 32 patients underwent KGK-PET and dPET using a one-day protocol. The sensitivity for the detection of primary/ recurrent head and neck cancer for KGK-PET and CT was 80% and 54%, respectively, specificity was 73% and 82%, respectively. The sensitivity and specificity for the detection of lymph node metastases based on neck sides with KGK-PET was 71% (CT: 65%) and 88% (CT: 89%) respectively. In comparison to dPET, KGK-PET revealed concordant results in 32/32 patients with respect to primary tumor/recurrent disease and in 55/60 evaluated neck sides. All involved neck sides that were missed by KGK-PET were also negative with dPET. These results indicate that in patients with head and neck cancer KGK-PET reveals information, that are similar to dPET and complementary to CT. (orig.) [de

  16. Testing of the dual slab verification detector for attended measurements of the BN-350 dry storage casks

    Energy Technology Data Exchange (ETDEWEB)

    Santi, Peter A [Los Alamos National Laboratory; Browne, Michael C [Los Alamos National Laboratory; Williams, Richard B [Los Alamos National Laboratory; Parker, Robert F [Los Alamos National Laboratory

    2009-01-01

    The Dual Slab Verification Detector (DSVD) has been developed and built by Los Alamos National Laboratory in cooperation with the International Atomic Energy Agency (IAEA) as part of the dry storage safeguards system for the spent fuel from the BN-350 fast reactor. The detector consists of two rows of {sup 3}He tubes embedded in a slab of polyethylene which has been designed to be placed on the outer surface of the dry storage cask. The DSVD will be used to perform measurements of the neutron flux emanating from inside the dry storage cask at several locations around each cask to establish a neutron 'fingerprint' that is sensitive to the contents of the cask. The sensitivity of the fingerprinting technique to the removal of specific amount of nuclear material from the cask is determined by the characteristics of the detector that is used to perform the measurements, the characteristics of the spent fuel being measured, and systematic uncertainties that are associated with the dry storage scenario. MCNPX calculations of the BN-350 dry storage asks and layout have shown that the neutron fingerprint verification technique using measurements from the DSVD would be sensitive to both the amount and location of material that is present within an individual cask. To confirm the performance of the neutron fingerprint technique in verifying the presence of BN-350 spent fuel in dry storage, an initial series of measurements have been performed to test the performance and characteristics of the DSVD. Results of these measurements will be presented and compared with MCNPX results.

  17. SU-G-IeP2-09: Iodine Imaging at Spectral CT with a Dual-Layer Detector

    Energy Technology Data Exchange (ETDEWEB)

    Ozguner, O [Case Western Reserve University, Cleveland, Ohio (United States); Dhanantwari, A; Halliburton, S; Utrup, S [Philips Healthcare, Highland Heights, OH (United States); Wen, G [The University of Texas at Austin, Austin, TX (United States); Jordan, D [University Hospitals Case Medical Center, Cleveland, OH (United States)

    2016-06-15

    Purpose: To evaluate the attenuation response of iodine and the accuracy of iodine quantification on a detector-based spectral CT scanner. Methods: A Gammex 461A phantom was scanned using a dual-layer detector (IQon, Philips) at 120 kVp using helical acquisition with a CDTIvol of 15 mGy to approximate the hospital’s clinical body protocol. No modifications to the standard protocol were necessary to enable spectral imaging. Iodine inserts at 6 concentrations (2, 5, 7.5, 10, 15, 20 mg/ml) were scanned individually at the center of the phantom and the 20 mg/ml insert was additionally scanned at the 3, 6, and 12 o’clock positions. Scans were repeated 10 times. Conventional, virtual monoenergetic (40–200 keV) and iodine-no-water images (with pixel values equal to iodine concentration of corresponding tissue) were reconstructed from acquired data. A circular ROI (diameter=30 pixels) was used in each conventional and monoenergetic image to measure the mean and standard deviation of the CT number in HU and in each iodine-no-water image to measure iodine concentration in mg/ml. Results: Mean CT number and contrast-to-noise ratio (CNR) measured from monoenergetic images increased with decreasing keV for all iodine concentrations and matched measurements from conventional images at 75 keV. Measurements from the 20 ml insert showed the CT number is independent of location and CNR is a function only of noise, which was higher in the center. Measured concentration from iodine-no-water images matched phantom manufacturer suggested concentration to within 6% on average for inserts at the center of the phantom. Measured concentrations were systematically higher due to optimization of iodine quantification parameters for clinical mixtures of iodine and blood/tissue. Conclusion: Spectral acquisition and reconstruction with a dual-layer detector represents the physical behavior of iodine as expected and accurately quantifies the material concentration. This should permit a

  18. Objective image characterization of a spectral CT scanner with dual-layer detector

    Science.gov (United States)

    Ozguner, Orhan; Dhanantwari, Amar; Halliburton, Sandra; Wen, Gezheng; Utrup, Steven; Jordan, David

    2018-01-01

    This work evaluated the performance of a detector-based spectral CT system by obtaining objective reference data, evaluating attenuation response of iodine and accuracy of iodine quantification, and comparing conventional CT and virtual monoenergetic images in three common phantoms. Scanning was performed using the hospital’s clinical adult body protocol. Modulation transfer function (MTF) was calculated for a tungsten wire and visual line pair targets were evaluated. Image noise power spectrum (NPS) and pixel standard deviation were calculated. MTF for monoenergetic images agreed with conventional images within 0.05 lp cm-1. NPS curves indicated that noise texture of 70 keV monoenergetic images is similar to conventional images. Standard deviation measurements showed monoenergetic images have lower noise except at 40 keV. Mean CT number and CNR agreed with conventional images at 75 keV. Measured iodine concentration agreed with true concentration within 6% for inserts at the center of the phantom. Performance of monoenergetic images at detector based spectral CT is the same as, or better than, that of conventional images. Spectral acquisition and reconstruction with a detector based platform represents the physical behaviour of iodine as expected and accurately quantifies the material concentration.

  19. Invited article: The fast readout low noise camera as a versatile x-ray detector for time resolved dispersive extended x-ray absorption fine structure and diffraction studies of dynamic problems in materials science, chemistry, and catalysis

    International Nuclear Information System (INIS)

    Labiche, Jean-Claude; Mathon, Olivier; Pascarelli, Sakura; Newton, Mark A.; Ferre, Gemma Guilera; Curfs, Caroline; Vaughan, Gavin; Homs, Alejandro; Carreiras, David Fernandez

    2007-01-01

    Originally conceived and developed at the European Synchrotron Radiation Facility (ESRF) as an 'area' detector for rapid x-ray imaging studies, the fast readout low noise (FReLoN) detector of the ESRF [J.-C. Labiche, ESRF Newsletter 25, 41 (1996)] has been demonstrated to be a highly versatile and unique detector. Charge coupled device (CCD) cameras at present available on the public market offer either a high dynamic range or a high readout speed. A compromise between signal dynamic range and readout speed is always sought. The parameters of the commercial cameras can sometimes be tuned, in order to better fulfill the needs of specific experiments, but in general these cameras have a poor duty cycle (i.e., the signal integration time is much smaller than the readout time). In order to address scientific problems such as time resolved experiments at the ESRF, a FReLoN camera has been developed by the Instrument Support Group at ESRF. This camera is a low noise CCD camera that combines high dynamic range, high readout speed, accuracy, and improved duty cycle in a single image. In this paper, we show its application in a quasi-one-dimensional sense to dynamic problems in materials science, catalysis, and chemistry that require data acquisition on a time scale of milliseconds or a few tens of milliseconds. It is demonstrated that in this mode the FReLoN can be applied equally to the investigation of rapid changes in long range order (via diffraction) and local order (via energy dispersive extended x-ray absorption fine structure) and in situations of x-ray hardness and flux beyond the capacity of other detectors

  20. Dual detector pulsed neutron logging for providing indication of formation porosity

    International Nuclear Information System (INIS)

    Hopkinson, E.C.

    1980-01-01

    A new improved apparatus for determining rock formation porosity was developed which is substantially independent of the formation salinity. The improvements achieved by using differing gating intervals for the two detectors. The rock formations surrounding the earth borehole are first pulse-irradiated with discrete bursts from a high-energy neutron source. The radiations at two different points in the formation are detected and electrical signals are generated. The electrical signals from the first point are gated for a shorter time interval than those from the second point. The gated first and second electrical signals are combined to determine the porosity of the formations. (DN)

  1. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    A positron emission tomography camera having a plurality of detector rings positioned side-by-side or offset by one-half of the detector cross section around a patient area to detect radiation therefrom. Each ring contains a plurality of scintillation detectors which are positioned around an inner circumference with a septum ring extending inwardly from the inner circumference along each outer edge of each ring. An additional septum ring is positioned in the middle of each ring of detectors and parallel to the other septa rings, whereby the inward extent of all the septa rings may be reduced by one-half and the number of detectors required in each ring is reduced. The additional septa reduces the costs of the positron camera and improves its performance

  2. Evaluation of dual-phase multi-detector-row CT for detection of intestinal bleeding using an experimental bowel model

    International Nuclear Information System (INIS)

    Dobritz, Martin; Engels, Heinz-Peter; Wieder, Hinrich; Rummeny, Ernst J.; Stollfuss, Jens C.; Schneider, Armin; Feussner, Hubertus

    2009-01-01

    To evaluate dual-phase multi-detector-row computed tomography (MDCT) in the detection of intestinal bleeding using an experimental bowel model and varying bleeding velocities. The model consisted of a high pressure injector tube with a single perforation (1 mm) placed in 10-m-long small bowel of a pig. The bowel was filled with water/contrast solution of 30-40 HU and was incorporated in a phantom model containing vegetable oil to simulate mesenteric fat. Intestinal bleeding in different locations and bleeding velocities varying from zero to 1 ml/min (0.05 ml/min increments, constant bleeding duration of 20 s) was simulated. Nineteen complete datasets in arterial and portal-venous phase using increasing bleeding velocities, and seven negative controls were measured using a 64 MDCT (3-mm slice thickness, 1.5-mm reconstruction increment). Three radiologists blinded to the experimental settings evaluated the datasets in a random order. The likelihood for intestinal bleeding was assessed using a 5-point scale with subsequent ROC analysis. The sensitivity to detect bleeding was 0.44 for a bleeding velocity of 0.10-0.50 ml/min and 0.97 for 0.55-1.00 ml/min. The specificity was 1.00. The area under the curve was calculated to be 0.73, 0.88 and 0.89 for reader 1, 2 and 3, respectively. Dual-phase MDCT provides high sensitivity and specificity in the detection of intestinal bleeding with bleeding velocities of 0.5-1.0 ml/min. Therefore, MDCT should be considered as a primary diagnostic technique in the management of patients with suspected intestinal bleeding. (orig.)

  3. New nuclear medicine gamma camera systems

    International Nuclear Information System (INIS)

    Villacorta, Edmundo V.

    1997-01-01

    with the existing three gamma cameras, one with fixed opposed dual-head, these new gamma cameras are capable of entire patient coverage for general imaging procedures as well as for SPECT and anterior/posterior whole body scanning using low, medium, and high energies such as Technetium 99m, Gallium 67 and Iodine 131. Imaging procedures done in MMC include thyroid, bone, heart, liver, lungs, kidney, brain, and others: hepatobiliary, parathyroid, testicles, detection for gastrointestinal bleeding and abscesses, etc. An added new equipment in the nuclear laboratory is a Packard COBRA single detector automatic gamma well counter as a backup for our 5 detector counter of the same brand

  4. Diagnosis of myocardial viability by dual-head coincidence gamma camera fluorine-18 fluorodeoxyglucose positron emission tomography with and without non-uniform attenuation correction

    International Nuclear Information System (INIS)

    Nowak, B.; Zimmy, M.; Kaiser, H.-J.; Schaefer, W.; Reinartz, P.; Buell, U.; Schwarz, E.R.; Dahl, J. vom

    2000-01-01

    This study assessed a dual-head coincidence gamma camera (hybrid PET) equipped with single-photon transmission for myocardial fluorine-18 fluorodeoxyglucose (FDG) imaging by comparing this technique with conventional positron emission tomography (PET) using a dedicated ring PET scanner. Twenty-one patients were studied with dedicated FDG ring PET and FDG hybrid PET for evaluation of myocardial glucose metabolism, as well as technetium-99 m tetrofosmin single-photon emission tomography (SPET) to estimate myocardial perfusion. All patients underwent transmitted attenuation correction using germanium-68 rod sources for ring PET and caesium-137 point sources for hybrid PET. Ring PET and hybrid PET emission scans were started 61±12 and 98±15 min, respectively, after administration of 154±31 MBq FDG. Attenuation-corrected images were reconstructed iteratively for ring PET and hybrid PET (ac-hybrid PET), and non-attenuation-corrected images for hybrid PET (non-ac-hybrid PET) only. Tracer distribution was analysed semiquantitatively using a volumetric vector sampling method dividing the left ventricular wall into 13 segments. FDG distribution in non-ac-hybrid PET and ring PET correlated with r=0.36 (P<0.0001), and in ac-hybrid PET and ring PET with r=0.79 (P<0.0001). Non-ac-hybrid PET significantly overestimated FDG uptake in the apical and supra-apical segments, and underestimated FDG uptake in the remaining segments, with the exception of one lateral segment. Ac-hybrid PET significantly overestimated FDG uptake in the apical segment, and underestimated FDG uptake in only three posteroseptal segments. A three-grade score was used to classify diagnosis of viability by FDG PET in 136 segments with reduced perfusion as assessed by SPET. Compared with ring PET, non-ac-hybrid PET showed concordant diagnoses in 80 segments (59%) and ac-hybrid PET in 101 segments (74%) (P<0.001). Agreement between ring PET and non-ac-hybrid PET was best in the basal lateral wall and in the

  5. Feasibility and accuracy of dual-layer spectral detector computed tomography for quantification of gadolinium: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Hamersvelt, Robbert W. van; Willemink, Martin J.; Jong, Pim A. de; Schilham, Arnold M.R.; Leiner, Tim [University Medical Center Utrecht, Department of Radiology, P.O. Box 85500, Utrecht (Netherlands); Milles, Julien [CT Clinical Science, Philips HealthCare, Best (Netherlands); Vlassenbroek, Alain [CT Clinical Science, Philips HealthCare, Brussels (Belgium)

    2017-09-15

    The aim of this study was to evaluate the feasibility and accuracy of dual-layer spectral detector CT (SDCT) for the quantification of clinically encountered gadolinium concentrations. The cardiac chamber of an anthropomorphic thoracic phantom was equipped with 14 tubular inserts containing different gadolinium concentrations, ranging from 0 to 26.3 mg/mL (0.0, 0.1, 0.2, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0, 5.1, 10.6, 15.7, 20.7 and 26.3 mg/mL). Images were acquired using a novel 64-detector row SDCT system at 120 and 140 kVp. Acquisitions were repeated five times to assess reproducibility. Regions of interest (ROIs) were drawn on three slices per insert. A spectral plot was extracted for every ROI and mean attenuation profiles were fitted to known attenuation profiles of water and pure gadolinium using in-house-developed software to calculate gadolinium concentrations. At both 120 and 140 kVp, excellent correlations between scan repetitions and true and measured gadolinium concentrations were found (R > 0.99, P < 0.001; ICCs > 0.99, CI 0.99-1.00). Relative mean measurement errors stayed below 10% down to 2.0 mg/mL true gadolinium concentration at 120 kVp and below 5% down to 1.0 mg/mL true gadolinium concentration at 140 kVp. SDCT allows for accurate quantification of gadolinium at both 120 and 140 kVp. Lowest measurement errors were found for 140 kVp acquisitions. (orig.)

  6. Determination of the activity concentration of a 238 Pu solution by the defined solid angle method utilizing a novel dual diaphragm-detector assembly.

    Science.gov (United States)

    Aguiar, Julio C; Galiano, Eduardo; Arenillas, Pablo

    2005-08-01

    The activity concentration of a (238)Pu solution was measured by the determined solid angle method employing a novel dual diaphragm-detector assembly, which has been previously described. Due to the special requirements of the detector, a new type of source holder was developed, which consisted of sandwiching the radioisotope between two organic films called VYNS. It was experimentally demonstrated that the VYNS films do not absorb alpha particles, but reduce their energy by an average of 22 keV.A mean activity concentration for (238)Pu of 359.10+/-0.8 kBq/g was measured.

  7. Determination of the activity concentration of a {sup 238}Pu solution by the defined solid angle method utilizing a novel dual diaphragm-detector assembly

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Julio C. [Departamento de Postgrado, Universidad Tecnologica Nacional, Buenos Aires (Argentina); Galiano, Eduardo [Departament of Physics, Laurentian University, Sudbury, Ont. P3E 2C6 (Canada)]. E-mail: egalianoriveros@laurentian.ca; Arenillas, Pablo [Comision Nacional de Energia Atomica, CAE, Laboratorio de Metrologia de Radioisotopos, Buenos Aires (Argentina)

    2005-08-01

    The activity concentration of a {sup 238}Pu solution was measured by the determined solid angle method employing a novel dual diaphragm-detector assembly, which has been previously described. Due to the special requirements of the detector, a new type of source holder was developed, which consisted of sandwiching the radioisotope between two organic films called VYNS. It was experimentally demonstrated that the VYNS films do not absorb {alpha} particles, but reduce their energy by an average of 22keV.A mean activity concentration for {sup 238}Pu of 359.10+/-0.8kBq/g was measured.

  8. Determination of the activity concentration of a 238Pu solution by the defined solid angle method utilizing a novel dual diaphragm-detector assembly

    International Nuclear Information System (INIS)

    Aguiar, Julio C.; Galiano, Eduardo; Arenillas, Pablo

    2005-01-01

    The activity concentration of a 238 Pu solution was measured by the determined solid angle method employing a novel dual diaphragm-detector assembly, which has been previously described. Due to the special requirements of the detector, a new type of source holder was developed, which consisted of sandwiching the radioisotope between two organic films called VYNS. It was experimentally demonstrated that the VYNS films do not absorb α particles, but reduce their energy by an average of 22keV.A mean activity concentration for 238 Pu of 359.10+/-0.8kBq/g was measured

  9. A dual channel optical detector for trace water chemodosimetry and imaging of live cells.

    Science.gov (United States)

    Men, Guangwen; Zhang, Guirong; Liang, Chunshuang; Liu, Huiling; Yang, Bing; Pan, Yuyu; Wang, Zhenyu; Jiang, Shimei

    2013-05-21

    A novel 3-5-dichlorosalicylaldehyde Schiff base chemodosimeter (compound 1) for water is designed and synthesized, and it works based on a water-triggered reaction of a Schiff base. Addition of trace amounts of water into 1 in various organic solvents leads to a fluorescence turn-on response and a simultaneous dual-channel signal modulation (both in the fluorescence and absorption spectra). Especially, 1 is found to be an outstanding fluorescence enhancement water sensor in methanol with an extremely low detection limit of 22 ppm. Consequently this probe can be utilized to detect trace water in commercial methanol. The quantitative detection of a wide range of water content is enhanced in THF and acetonitrile (0-35% v/v for THF and 0-20% v/v for acetonitrile), where the fluorescence peak intensity is nearly proportional to the amount of water added. Moreover, 1 can be used for monitoring pH through a novel ON-OFF-ON type signal modulation both in fluorescence and absorption spectra within a wide pH detection range. Thus, the chemodosimeter can not only be utilized to monitor the intracellular pH fluctuations, but also to accomplish simultaneous in situ staining of the cytosol and acidic organelles in two different channels, respectively.

  10. Comparison of virtual monoenergetic and polyenergetic images reconstructed from dual-layer detector CT angiography of the head and neck.

    Science.gov (United States)

    Neuhaus, Victor; Große Hokamp, Nils; Abdullayev, Nuran; Maus, Volker; Kabbasch, Christoph; Mpotsaris, Anastasios; Maintz, David; Borggrefe, Jan

    2018-03-01

    To compare the image quality of virtual monoenergetic images and polyenergetic images reconstructed from dual-layer detector CT angiography (DLCTA). Thirty patients who underwent DLCTA of the head and neck were retrospectively identified and polyenergetic as well as virtual monoenergetic images (40 to 120 keV) were reconstructed. Signals (± SD) of the cervical and cerebral vessels as well as lateral pterygoid muscle and the air surrounding the head were measured to calculate the CNR and SNR. In addition, subjective image quality was assessed using a 5-point Likert scale. Student's t-test and Wilcoxon test were used to determine statistical significance. Compared to polyenergetic images, although noise increased with lower keV, CNR (p 0.05) of the cervical, petrous and intracranial vessels were improved in virtual monoenergetic images at 40 keV and virtual monoenergetic images at 45 keV were also rated superior regarding vascular contrast, assessment of arteries close to the skull base and small arterial branches (p virtual monoenergetic images reconstructed from DLCTA at low keV ranging from 40 to 45 keV improve the objective and subjective image quality of extra- and intracranial vessels and facilitate assessment of vessels close to the skull base and of small arterial branches. • Virtual monoenergetic images greatly improve attenuation, while noise only slightly increases. • Virtual monoenergetic images show superior contrast-to-noise ratios compared to polyenergetic images. • Virtual monoenergetic images significantly improve image quality at low keV.

  11. Comparison of virtual monoenergetic and polyenergetic images reconstructed from dual-layer detector CT angiography of the head and neck

    Energy Technology Data Exchange (ETDEWEB)

    Neuhaus, Victor; Grosse Hokamp, Nils; Abdullayev, Nuran; Maus, Volker; Kabbasch, Christoph; Mpotsaris, Anastasios; Maintz, David; Borggrefe, Jan [University Hospital Cologne, Department of Diagnostic and Interventional Radiology, Cologne (Germany)

    2018-03-15

    To compare the image quality of virtual monoenergetic images and polyenergetic images reconstructed from dual-layer detector CT angiography (DLCTA). Thirty patients who underwent DLCTA of the head and neck were retrospectively identified and polyenergetic as well as virtual monoenergetic images (40 to 120 keV) were reconstructed. Signals (± SD) of the cervical and cerebral vessels as well as lateral pterygoid muscle and the air surrounding the head were measured to calculate the CNR and SNR. In addition, subjective image quality was assessed using a 5-point Likert scale. Student's t-test and Wilcoxon test were used to determine statistical significance. Compared to polyenergetic images, although noise increased with lower keV, CNR (p < 0.02) and SNR (p > 0.05) of the cervical, petrous and intracranial vessels were improved in virtual monoenergetic images at 40 keV and virtual monoenergetic images at 45 keV were also rated superior regarding vascular contrast, assessment of arteries close to the skull base and small arterial branches (p < 0.0001 each). Compared to polyenergetic images, virtual monoenergetic images reconstructed from DLCTA at low keV ranging from 40 to 45 keV improve the objective and subjective image quality of extra- and intracranial vessels and facilitate assessment of vessels close to the skull base and of small arterial branches. (orig.)

  12. Reduced iodinated contrast media for abdominal imaging by dual-layer spectral detector computed tomography for patients with kidney disease

    Directory of Open Access Journals (Sweden)

    Hirokazu Saito, MD

    2018-04-01

    Full Text Available Contrast-enhanced computed tomography using iodinated contrast media is useful for diagnosis of gastrointestinal diseases. However, contrast-induced nephropathy remains problematic for kidney diseases patients. Although current guidelines recommended the use of a minimal dose of contrast media necessary to obtain adequate images for diagnosis, obtaining adequate images with sufficient contrast enhancement is difficult with conventional computed tomography using reduced contrast media. Dual-layer spectral detector computed tomography enables the simultaneous acquisition of low- and high-energy data and the reconstruction of virtual monochromatic images ranging from 40 to 200 keV, retrospectively. Low-energy virtual monochromatic images can enhance the contrast of images, thereby facilitating reduced contrast media. In case 1, abdominal computed tomography angiography at 50 keV using 40% of the conventional dose of contrast media revealed the artery that was the source of diverticular bleeding in the ascending colon. In case 2, ischemia of the transverse colon was diagnosed by contrast-enhanced computed tomography and iodine-selective imaging using 40% of the conventional dose of contrast media. In case 3, advanced esophagogastric junctional cancer was staged and preoperative abdominal computed tomography angiography could be obtained with 30% of the conventional dose of contrast media. However, the texture of virtual monochromatic images may be a limitation at low energy. Keywords: Virtual monochromatic images, Contrast-induced nephropathy

  13. The effect of amorphous selenium detector thickness on dual-energy digital breast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yue-Houng, E-mail: yuehoung.hu@gmail.com; Zhao, Wei [Department of Radiology, State University of New York at Stony Brook, L-4 120 Health Sciences Center, Stony Brook, New York 11794-8460 (United States)

    2014-11-01

    Purpose: Contrast enhanced (CE) imaging techniques for both planar digital mammography (DM) and three-dimensional (3D) digital breast tomosynthesis (DBT) applications requires x-ray photon energies higher than the k-edge of iodine (33.2 keV). As a result, x-ray tube potentials much higher (>40 kVp) than those typical for screening mammography must be utilized. Amorphous selenium (a-Se) based direct conversion flat-panel imagers (FPI) have been widely used in DM and DBT imaging systems. The a-Se layer is typically 200 μm thick with quantum detective efficiency (QDE) >87% for x-ray energies below 26 keV. However, QDE decreases substantially above this energy. To improve the object detectability of either CE-DM or CE-DBT, it may be advantageous to increase the thickness (d{sub Se}) of the a-Se layer. Increasing the d{sub Se} will improve the detective quantum efficiency (DQE) at the higher energies used in CE imaging. However, because most DBT systems are designed with partially isocentric geometries, where the gantry moves about a stationary detector, the oblique entry of x-rays will introduce additional blur to the system. The present investigation quantifies the effect of a-Se thickness on imaging performance for both CE-DM and CE-DBT, discussing the effects of improving photon absorption and blurring from oblique entry of x-rays. Methods: In this paper, a cascaded linear system model (CLSM) was used to investigate the effect of d{sub Se} on the imaging performance (i.e., MTF, NPS, and DQE) of FPI in CE-DM and CE-DBT. The results from the model are used to calculate the ideal observer signal-to-noise ratio, d′, which is used as a figure-of-merit to determine the total effect of increasing d{sub Se} for CE-DM and CE-DBT. Results: The results of the CLSM show that increasing d{sub Se} causes a substantial increase in QDE at the high energies used in CE-DM. However, at the oblique projection angles used in DBT, the increased length of penetration through a

  14. Dual-modality imaging with a ultrasound-gamma device for oncology

    Science.gov (United States)

    Polito, C.; Pellegrini, R.; Cinti, M. N.; De Vincentis, G.; Lo Meo, S.; Fabbri, A.; Bennati, P.; Cencelli, V. Orsolini; Pani, R.

    2018-06-01

    Recently, dual-modality systems have been developed, aimed to correlate anatomical and functional information, improving disease localization and helping oncological or surgical treatments. Moreover, due to the growing interest in handheld detectors for preclinical trials or small animal imaging, in this work a new dual modality integrated device, based on a Ultrasounds probe and a small Field of View Single Photon Emission gamma camera, is proposed.

  15. Unmanned Ground Vehicle Perception Using Thermal Infrared Cameras

    Science.gov (United States)

    Rankin, Arturo; Huertas, Andres; Matthies, Larry; Bajracharya, Max; Assad, Christopher; Brennan, Shane; Bellutta, Paolo; Sherwin, Gary W.

    2011-01-01

    The ability to perform off-road autonomous navigation at any time of day or night is a requirement for some unmanned ground vehicle (UGV) programs. Because there are times when it is desirable for military UGVs to operate without emitting strong, detectable electromagnetic signals, a passive only terrain perception mode of operation is also often a requirement. Thermal infrared (TIR) cameras can be used to provide day and night passive terrain perception. TIR cameras have a detector sensitive to either mid-wave infrared (MWIR) radiation (3-5?m) or long-wave infrared (LWIR) radiation (8-12?m). With the recent emergence of high-quality uncooled LWIR cameras, TIR cameras have become viable passive perception options for some UGV programs. The Jet Propulsion Laboratory (JPL) has used a stereo pair of TIR cameras under several UGV programs to perform stereo ranging, terrain mapping, tree-trunk detection, pedestrian detection, negative obstacle detection, and water detection based on object reflections. In addition, we have evaluated stereo range data at a variety of UGV speeds, evaluated dual-band TIR classification of soil, vegetation, and rock terrain types, analyzed 24 hour water and 12 hour mud TIR imagery, and analyzed TIR imagery for hazard detection through smoke. Since TIR cameras do not currently provide the resolution available from megapixel color cameras, a UGV's daytime safe speed is often reduced when using TIR instead of color cameras. In this paper, we summarize the UGV terrain perception work JPL has performed with TIR cameras over the last decade and describe a calibration target developed by General Dynamics Robotic Systems (GDRS) for TIR cameras and other sensors.

  16. Chronic bacterial osteomyelitis: prospective comparison of 18F-FDG imaging with a dual-head coincidence camera and 111In-labelled autologous leucocyte scintigraphy

    International Nuclear Information System (INIS)

    Meller, J.; Siefker, U.; Lehmann, K.; Meyer, I.; Schreiber, K.; Altenvoerde, G.; Becker, W.; Liersch, T.

    2002-01-01

    Indium-111-labelled white blood cells ( 111 In-WBCs) are currently considered the tracer of choice in the diagnostic work-up of suspected active chronic osteomyelitis (COM). Previous studies in a limited number of patients, performed with dedicated PET systems, have shown that [ 18 F]2'-deoxy-2-fluoro-D-glucose (FDG) imaging may offer at least similar diagnostic accuracy. The aim of this prospective study was to compare FDG imaging with a dual-head coincidence camera (DHCC) and 111 In-WBC imaging in patients with suspected COM. Thirty consecutive non-diabetic patients with possible COM underwent combined skeletal scintigraphy (30/30 patients), 111 In-WBC imaging (28/30 patients) and FDG-PET with a DHCC (30/30 patients). During diagnostic work-up, COM was proven in 11/36 regions of suspected skeletal infection and subsequently excluded in 25/36 regions. In addition, soft tissue infection was present in five patients and septic arthritis in three. 111 In-WBC imaging in 28 patients was true positive in 2/11 regions with proven COM and true negative in 21/23 regions without further evidence of COM. False-positive results occurred in two regions and false-negative results in nine regions suspected for COM. Most of the false-negative results (7/9) occurred in the central skeleton. If the analysis was restricted to the 18 regions with available histology (n=17) or culture (n=1), 111 In-WBC imaging was true positive in 2/18 regions, true negative in 8/18 regions, false negative in 7/18 regions and false positive in 1/18 regions. FDG-DHCC imaging was true positive in 11/11 regions with proven COM and true negative in 23/25 regions without further evidence of COM. False-positive results occurred in two regions. If the analysis was restricted to the 19 regions with available histology (n=18) or culture (n=1), FDG-DHCC imaging was true positive in 9/9 regions with proven COM and true negative in 10/10 regions without further evidence of COM. It is concluded that FDG

  17. Optimization of dual-energy subtraction chest radiography by use of a direct-conversion flat-panel detector system.

    Science.gov (United States)

    Fukao, Mari; Kawamoto, Kiyosumi; Matsuzawa, Hiroaki; Honda, Osamu; Iwaki, Takeshi; Doi, Tsukasa

    2015-01-01

    We aimed to optimize the exposure conditions in the acquisition of soft-tissue images using dual-energy subtraction chest radiography with a direct-conversion flat-panel detector system. Two separate chest images were acquired at high- and low-energy exposures with standard or thick chest phantoms. The high-energy exposure was fixed at 120 kVp with the use of an auto-exposure control technique. For the low-energy exposure, the tube voltages and entrance surface doses ranged 40-80 kVp and 20-100 % of the dose required for high-energy exposure, respectively. Further, a repetitive processing algorithm was used for reduction of the image noise generated by the subtraction process. Seven radiology technicians ranked soft-tissue images, and these results were analyzed using the normalized-rank method. Images acquired at 60 kVp were of acceptable quality regardless of the entrance surface dose and phantom size. Using a repetitive processing algorithm, the minimum acceptable doses were reduced from 75 to 40 % for the standard phantom and to 50 % for the thick phantom. We determined that the optimum low-energy exposure was 60 kVp at 50 % of the dose required for the high-energy exposure. This allowed the simultaneous acquisition of standard radiographs and soft-tissue images at 1.5 times the dose required for a standard radiograph, which is significantly lower than the values reported previously.

  18. The world's fastest camera

    CERN Multimedia

    Piquepaille, Roland

    2006-01-01

    This image processor is not your typical digital camera. It took 6 years to 20 people and $6 million to build the "Regional Calorimeter Trigger"(RCT) which will be a component of the Compact Muon Solenoid (CMS) experiment, one of the detectors on the Large Hadron Collider (LHC) in Geneva, Switzerland (1 page)

  19. An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

    Energy Technology Data Exchange (ETDEWEB)

    Bolotnikov, A. E., E-mail: bolotnik@bnl.gov; Ackley, K.; Camarda, G. S.; Cherches, C.; Cui, Y.; De Geronimo, G.; Fried, J.; Hossain, A.; Mahler, G.; Maritato, M.; Roy, U.; Salwen, C.; Vernon, E.; Yang, G.; James, R. B. [Brookhaven National Laboratory, Upton, New York 11793 (United States); Hodges, D. [University of Texas at El Paso, El Paso, Texas 79968 (United States); Lee, W. [Korea University, Seoul 136-855 (Korea, Republic of); Petryk, M. [SUNY Binghamton, Vestal, New York 13902 (United States)

    2015-07-15

    We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm{sup 3} detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays’ performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

  20. Left ventricular function assessment using 123I/99mTc dual-isotope acquisition with two semi-conductor cadmium–zinc–telluride (CZT cameras: a gated cardiac phantom study

    Directory of Open Access Journals (Sweden)

    Tanguy Blaire

    2016-11-01

    Full Text Available Abstract Background The impact of increased energy resolution of cadmium–zinc–telluride (CZT cameras on the assessment of left ventricular function under dual-isotope conditions (99mTc and 123I remains unknown. The Amsterdam-gated dynamic cardiac phantom (AGATE, Vanderwilt techniques, Boxtel, The Netherlands was successively filled with a solution of 123I alone, 99mTc alone, and a mixture of 123I and 99mTc. A total of 12 datasets was acquired with each commercially available CZT camera (DNM 530c, GE Healthcare and DSPECT, Biosensors International using both energy windows (99mTc or 123I with ejection fraction set to 33, 45, and 60 %. End-diastolic (EDV and end-systolic (ESV volumes, ejection fraction (LVEF, and regional wall motion and thickening (17-segment model were assessed using Cedars-Sinai QGS Software. Concordance between single- and dual-isotope acquisitions was tested using Lin’s concordance correlation coefficient (CCC and Bland–Altman plots. Results There was no significant difference between single- or simultaneous dual-isotope acquisition (123I and 99mTc for EDV, ESV, LVEF, or segmental wall motion and thickening. Myocardial volumes using single- (123I, 99mTc and dual-isotope (reconstructed using both 123I and 99mTc energy windows acquisitions were, respectively, the following: EDV (mL 88 ± 27 vs. 89 ± 27 vs. 92 ± 29 vs. 90 ± 26 for DNM 530c (p = NS and 82 ± 20 vs. 83 ± 22 vs. 79 ± 19 vs. 77 ± 20 for DSPECT (p = NS; ESV (mL 40 ± 1 vs. 41 ± 2 vs. 41 ± 2 vs. 42 ± 1 for DNM 530c (p = NS and 37 ± 5 vs. 37 ± 1 vs. 35 ± 3 vs. 34 ± 2 for DSPECT (p = NS; LVEF (% 52 ± 14 vs. 51 ± 13 vs. 53 ± 13 vs. 51 ± 13 for DNM 530c (p = NS and 52 ± 16 vs. 54 ± 13 vs. 54 ± 14 vs. 54 ± 13 for DSPECT (p = NS; regional motion (mm 6.72 ± 2.82 vs. 6.58 ± 2.52 vs. 6.86 ± 2.99 vs. 6.59 ± 2

  1. Material decomposition through weighted imaged subtraction in dual-energy spectral mammography with an energy-resolved photon-counting detector using Monte Carlo Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Ji Soo; Kang, Soon Cheol; Lee, Seung Wan [Konyang University, Daejeon (Korea, Republic of)

    2017-09-15

    Mammography is commonly used for screening early breast cancer. However, mammographic images, which depend on the physical properties of breast components, are limited to provide information about whether a lesion is malignant or benign. Although a dual-energy subtraction technique decomposes a certain material from a mixture, it increases radiation dose and degrades the accuracy of material decomposition. In this study, we simulated a breast phantom using attenuation characteristics, and we proposed a technique to enable the accurate material decomposition by applying weighting factors for the dual-energy mammography based on a photon-counting detector using a Monte Carlo simulation tool. We also evaluated the contrast and noise of simulated breast images for validating the proposed technique. As a result, the contrast for a malignant tumor in the dual-energy weighted subtraction technique was 0.98 and 1.06 times similar than those in the general mammography and dual-energy subtraction techniques, respectively. However the contrast between malignant and benign tumors dramatically increased 13.54 times due to the low contrast of a benign tumor. Therefore, the proposed technique can increase the material decomposition accuracy for malignant tumor and improve the diagnostic accuracy of mammography.

  2. A Planar, Chip-Based, Dual-Beam Refractometer Using an Integrated Organic Light Emitting Diode (OLED) Light Source and Organic Photovoltaic (OPV) Detectors

    Science.gov (United States)

    Ratcliff, Erin L.; Veneman, P. Alex; Simmonds, Adam; Zacher, Brian; Huebner, Daniel

    2010-01-01

    We present a simple chip-based refractometer with a central organic light emitting diode (OLED) light source and two opposed organic photovoltaic (OPV) detectors on an internal reflection element (IRE) substrate, creating a true dual-beam sensor platform. For first-generation platforms, we demonstrate the use of a single heterojunction OLED based on electroluminescence emission from an Alq3/TPD heterojunction (tris-(8-hydroxyquinoline)aluminum/N,N′-Bis(3-methylphenyl)-N,N′-diphenylbenzidine) and light detection with planar heterojunction pentacene/C60 OPVs. The sensor utilizes the considerable fraction of emitted light from conventional thin film OLEDs that is coupled into guided modes in the IRE instead of into the forward (display) direction. A ray-optics description is used to describe light throughput and efficiency-limiting factors for light coupling from the OLED into the substrate modes, light traversing through the IRE substrate, and light coupling into the OPV detectors. The arrangement of the OLED at the center of the chip provides for two sensing regions, a “sample” and “reference” channel, with detection of light by independent OPV detectors. This configuration allows for normalization of the sensor response against fluctuations in OLED light output, stability, and local fluctuations (temperature) which might influence sensor response. The dual beam configuration permits significantly enhanced sensitivity to refractive index changes relative to single-beam protocols, and is easily integrated into a field-portable instrumentation package. Changes in refractive index (ΔR.I.) between 10−2 and 10−3 R.I. units could be detected for single channel operation, with sensitivity increased to ΔR.I. ≈ 10−4 units when the dual beam configuration is employed. PMID:20218580

  3. Initial clinical experience with dual-layer detector spectral CT in patients with acute intracerebral haemorrhage: A single-centre pilot study.

    Directory of Open Access Journals (Sweden)

    Soo Buem Cho

    Full Text Available The purpose of this study was to investigate the clinical feasibility of spectral analyses using dual-layer detector spectral computed tomography (CT in acute intracerebral haemorrhage (ICH.We retrospectively reviewed patients with acute ICH who underwent CT angiography on a dual-layer detector spectral CT scanner. A spectral data analysis was performed to detect contrast enhancement in or adjacent to acute ICH by using spectral image reconstructions including monoenergetic (MonoE, virtual noncontrast (VNC, and iodine overlay fusion images. We also acquired a spectral plot to assess material differentiation within lesions.Among the 30 patients, the most common cause of acute ICH was chronic hypertension (18/30, 60% followed by trauma (5/30, 16.7%, brain tumour (3/30, 10%, Moyamoya disease (2/30, 6.7%, and haemorrhagic diathesis from anticoagulation therapy (2/30, 6.7%. Of 30 patients, 13 showed suboptimal iodine suppression in the subcalvarial spaces on VNC images compared with true noncontrast images. The CT angiographic spot sign within the acute ICH was detected in four patients (4/30, 13.3%. All three tumours were metastatic and included lung cancer (n = 2 and hepatocellular carcinoma (n = 1 which showed conspicuous delineation of an enhancing tumour portion in the spectral analysis. Spectral analyses allowed the discrimination of acute haemorrhage and iodine with enhanced lesion visualization on the MonoE images obtained at lower keVs (less than 70 keV and spectral plot.Even though the image quality of VNC is perceived to be inferior, it is feasible to evaluate acute ICH in clinical settings using dual-layer detector spectral CT. The MonoE images taken at lower keVs were useful for depicting contrast enhancing lesion, and spectral plot might be helpful for material differentiation in patients with acute ICH.

  4. Initial clinical experience with dual-layer detector spectral CT in patients with acute intracerebral haemorrhage: A single-centre pilot study.

    Science.gov (United States)

    Cho, Soo Buem; Baek, Hye Jin; Ryu, Kyeong Hwa; Moon, Jin Il; Choi, Bo Hwa; Park, Sung Eun; Bae, Kyungsoo; Jeon, Kyung Nyeo; Kim, Dong Wook

    2017-01-01

    The purpose of this study was to investigate the clinical feasibility of spectral analyses using dual-layer detector spectral computed tomography (CT) in acute intracerebral haemorrhage (ICH). We retrospectively reviewed patients with acute ICH who underwent CT angiography on a dual-layer detector spectral CT scanner. A spectral data analysis was performed to detect contrast enhancement in or adjacent to acute ICH by using spectral image reconstructions including monoenergetic (MonoE), virtual noncontrast (VNC), and iodine overlay fusion images. We also acquired a spectral plot to assess material differentiation within lesions. Among the 30 patients, the most common cause of acute ICH was chronic hypertension (18/30, 60%) followed by trauma (5/30, 16.7%), brain tumour (3/30, 10%), Moyamoya disease (2/30, 6.7%), and haemorrhagic diathesis from anticoagulation therapy (2/30, 6.7%). Of 30 patients, 13 showed suboptimal iodine suppression in the subcalvarial spaces on VNC images compared with true noncontrast images. The CT angiographic spot sign within the acute ICH was detected in four patients (4/30, 13.3%). All three tumours were metastatic and included lung cancer (n = 2) and hepatocellular carcinoma (n = 1) which showed conspicuous delineation of an enhancing tumour portion in the spectral analysis. Spectral analyses allowed the discrimination of acute haemorrhage and iodine with enhanced lesion visualization on the MonoE images obtained at lower keVs (less than 70 keV) and spectral plot. Even though the image quality of VNC is perceived to be inferior, it is feasible to evaluate acute ICH in clinical settings using dual-layer detector spectral CT. The MonoE images taken at lower keVs were useful for depicting contrast enhancing lesion, and spectral plot might be helpful for material differentiation in patients with acute ICH.

  5. WE-FG-207B-11: Objective Image Characterization of Spectral CT with a Dual-Layer Detector

    International Nuclear Information System (INIS)

    Ozguner, O; Halliburton, S; Dhanantwari, A; Utrup, S; Wen, G; Jordan, D

    2016-01-01

    Purpose: To obtain objective reference data for the spectral performance on a dual-layer detector CT platform (IQon, Philips) and compare virtual monoenergetic to conventional CT images. Methods: Scanning was performed using the hospital’s clinical adult body protocol: helical acquisition at 120kVp, with CTDIvol=15mGy. Multiple modules (591, 515, 528) of a CATPHAN 600 phantom and a 20 cm diameter cylindrical water phantom were scanned. No modifications to the standard protocol were necessary to enable spectral imaging. Both conventional and virtual monoenergetic images were generated from acquired data. Noise characteristics were assessed through Noise Power Spectra (NPS) and pixel standard deviation from water phantom images. Spatial resolution was evaluated using Modulation Transfer Functions (MTF) of a tungsten wire as well as resolution bars. Low-contrast detectability was studied using contrast-to-noise ratio (CNR) of a low contrast object. Results: MTF curves of monoenergetic and conventional images were almost identical. MTF 50%, 10%, and 5% levels for monoenergetic images agreed with conventional images within 0.05lp/cm. These observations were verified by the resolution bars, which were clearly resolved at 7lp/cm but started blurring at 8lp/cm for this protocol in both conventional and 70 keV images. NPS curves indicated that, compared to conventional images, the noise power distribution of 70 keV monoenergetic images is similar (i.e. noise texture is similar) but exhibit a low frequency peak at keVs higher and lower than 70 keV. Standard deviation measurements show monoenergetic images have lower noise except at 40 keV where it is slightly higher. CNR of monoenergetic images is mostly flat across keV values and is superior to that of conventional images. Conclusion: Values for standard image quality metrics are the same or better for monoenergetic images compared to conventional images. Results indicate virtual monoenergetic images can be used without

  6. WE-FG-207B-11: Objective Image Characterization of Spectral CT with a Dual-Layer Detector

    Energy Technology Data Exchange (ETDEWEB)

    Ozguner, O [Case Western Reserve University, Cleveland, OH (United States); Halliburton, S; Dhanantwari, A; Utrup, S [Philips Healthcare, Highland Heights, OH (United States); Wen, G [The University of Texas at Austin, Austin, TX (United States); Jordan, D [University Hospitals Case Medical Center, Cleveland, OH (United States)

    2016-06-15

    Purpose: To obtain objective reference data for the spectral performance on a dual-layer detector CT platform (IQon, Philips) and compare virtual monoenergetic to conventional CT images. Methods: Scanning was performed using the hospital’s clinical adult body protocol: helical acquisition at 120kVp, with CTDIvol=15mGy. Multiple modules (591, 515, 528) of a CATPHAN 600 phantom and a 20 cm diameter cylindrical water phantom were scanned. No modifications to the standard protocol were necessary to enable spectral imaging. Both conventional and virtual monoenergetic images were generated from acquired data. Noise characteristics were assessed through Noise Power Spectra (NPS) and pixel standard deviation from water phantom images. Spatial resolution was evaluated using Modulation Transfer Functions (MTF) of a tungsten wire as well as resolution bars. Low-contrast detectability was studied using contrast-to-noise ratio (CNR) of a low contrast object. Results: MTF curves of monoenergetic and conventional images were almost identical. MTF 50%, 10%, and 5% levels for monoenergetic images agreed with conventional images within 0.05lp/cm. These observations were verified by the resolution bars, which were clearly resolved at 7lp/cm but started blurring at 8lp/cm for this protocol in both conventional and 70 keV images. NPS curves indicated that, compared to conventional images, the noise power distribution of 70 keV monoenergetic images is similar (i.e. noise texture is similar) but exhibit a low frequency peak at keVs higher and lower than 70 keV. Standard deviation measurements show monoenergetic images have lower noise except at 40 keV where it is slightly higher. CNR of monoenergetic images is mostly flat across keV values and is superior to that of conventional images. Conclusion: Values for standard image quality metrics are the same or better for monoenergetic images compared to conventional images. Results indicate virtual monoenergetic images can be used without

  7. Effects of reflector and crystal surface on the performance of a depth-encoding PET detector with dual-ended readout

    International Nuclear Information System (INIS)

    Ren, Silin; Yang, Yongfeng; Cherry, Simon R.

    2014-01-01

    Purpose: Depth encoding detectors are required to improve the spatial resolution and spatial resolution uniformity of small animal positron emission tomography (PET) scanners, as well as dedicated breast and brain scanners. Depth of interaction (DOI) can be measured by using dual-ended readout of lutetium oxyorthosilicate (LSO) scintillator arrays with position-sensitive avalanche photodiodes. Inter-crystal reflectors and crystal surface treatments play important roles in determining the performance of dual-ended detectors. In this paper, the authors evaluated five LSO arrays made with three different intercrystal reflectors and with either polished or unpolished crystal surfaces. Methods: The crystal size in all arrays was 1.5 mm, which is typical of the detector size used in small animal and dedicated breast scanners. The LSO arrays were measured with dual-ended readout and were compared in terms of flood histogram, energy resolution, and DOI resolution performance. Results: The four arrays using enhanced specular reflector (ESR) and Toray reflector provided similar quality flood histograms and the array using Crystal Wrap reflector gave the worst flood histogram. The two arrays using ESR reflector provided the best energy resolution and the array using Crystal Wrap reflector yielded the worst energy resolution. All arrays except the polished ESR array provided good DOI resolution ranging from 1.9 mm to 2.9 mm. DOI resolution improved as the gradient in light collection efficiency with depth (GLCED) increased. The geometric mean energies were also calculated for these dual-ended readout detectors as an alternative to the conventional summed total energy. It was shown that the geometric mean energy is advantageous in that it provides more uniform photopeak amplitude at different depths for arrays with high GLCED, and is beneficial in event selection by allowing a fixed energy window independent of depth. A new method of DOI calculation that improved the linearity

  8. Experimental characterization of a direct conversion amorphous selenium detector with thicker conversion layer for dual-energy contrast-enhanced breast imaging.

    Science.gov (United States)

    Scaduto, David A; Tousignant, Olivier; Zhao, Wei

    2017-08-01

    Dual-energy contrast-enhanced imaging is being investigated as a tool to identify and localize angiogenesis in the breast, a possible indicator of malignant tumors. This imaging technique requires that x-ray images are acquired at energies above the k-shell binding energy of an appropriate radiocontrast agent. Iodinated contrast agents are commonly used for vascular imaging, and require x-ray energies greater than 33 keV. Conventional direct conversion amorphous selenium (a-Se) flat-panel imagers for digital mammography show suboptimal absorption efficiencies at these higher energies. We use spatial-frequency domain image quality metrics to evaluate the performance of a prototype direct conversion flat-panel imager with a thicker a-Se layer, specifically fabricated for dual-energy contrast-enhanced breast imaging. Imaging performance was evaluated in a prototype digital breast tomosynthesis (DBT) system. The spatial resolution, noise characteristics, detective quantum efficiency, and temporal performance of the detector were evaluated for dual-energy imaging for both conventional full-field digital mammography (FFDM) and DBT. The zero-frequency detective quantum efficiency of the prototype detector is improved by approximately 20% over the conventional detector for higher energy beams required for imaging with iodinated contrast agents. The effect of oblique entry of x-rays on spatial resolution does increase with increasing photoconductor thickness, specifically for the most oblique views of a DBT scan. Degradation of spatial resolution due to focal spot motion was also observed. Temporal performance was found to be comparable to conventional mammographic detectors. Increasing the a-Se thickness in direct conversion flat-panel imagers results in better performance for dual-energy contrast-enhanced breast imaging. The reduction in spatial resolution due to oblique entry of x-rays is appreciable in the most extreme clinically relevant cases, but may not profoundly

  9. Prototype of high resolution PET using resistive electrode position sensitive CdTe detectors

    International Nuclear Information System (INIS)

    Kikuchi, Yohei; Ishii, Keizo; Matsuyama, Shigeo; Yamazaki, Hiromichi

    2008-01-01

    Downsizing detector elements makes it possible that spatial resolutions of positron emission tomography (PET) cameras are improved very much. From this point of view, semiconductor detectors are preferable. To obtain high resolution, the pixel type or the multi strip type of semiconductor detectors can be used. However, in this case, there is a low packing ratio problem, because a dead area between detector arrays cannot be neglected. Here, we propose the use of position sensitive semiconductor detectors with resistive electrode. The CdTe detector is promising as a detector for PET camera because of its high sensitivity. In this paper, we report development of prototype of high resolution PET using resistive electrode position sensitive CdTe detectors. We made 1-dimensional position sensitive CdTe detectors experimentally by changing the electrode thickness. We obtained 750 A as an appropriate thickness of position sensitive detectors, and evaluated the performance of the detector using a collimated 241 Am source. A good position resolution of 1.2 mm full width half maximum (FWHM) was obtained. On the basis of the fundamental development of resistive electrode position sensitive detectors, we constructed a prototype of high resolution PET which was a dual head type and was consisted of thirty-two 1-dimensional position sensitive detectors. In conclusion, we obtained high resolutions which are 0.75 mm (FWHM) in transaxial, and 1.5 mm (FWHM) in axial. (author)

  10. Centering mount for a gamma camera

    International Nuclear Information System (INIS)

    Mirkhodzhaev, A.Kh.; Kuznetsov, N.K.; Ostryj, Yu.E.

    1988-01-01

    A device for centering a γ-camera detector in case of radionuclide diagnosis is described. It permits the use of available medical coaches instead of a table with a transparent top. The device can be used for centering a detector (when it is fixed at the low end of a γ-camera) on a required area of the patient's body

  11. High-performance 1024x1024 MWIR/LWIR Dual-band InAs/GaSb Type-II Superlattice-based Camera System, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — High performance LWIR detectors are highly needed. In order to image from long distance, it is important that imagers have high sensitivity, high resolution, and...

  12. Two New Types of Detector for X- or Gamma-Ray Cameras; Deux Nouveaux Types de Detecteurs pour Camera a Rayons X ou {gamma}; O dvukh novykh tipov detektorov dlya rentgenovskikh ili gamma-kamer; Dos Nuevos Tipos de Detector para Camaras de Rayos X o Gamma

    Energy Technology Data Exchange (ETDEWEB)

    Kellershohn, C.; Desgrez, A. [Departement de Biologie, Service Hospitalier Frederic Joliot (France); Lansiart, A. [Departement d' Electronique, Centre d' Etudes Nucleaires de Saclay (France)

    1964-10-15

    X- or {gamma}-ray cameras consist essentially of a hole-type or grid-type lens system together with a detector. The authors propose two kinds of detector quite different from the Anger device, which so far has been the only one in practical use. The first consists of a self-triggering spark chamber. This chamber, about 20 cm in diam. and filled with a rare gas (argon or xenon), forms a cathode and two grids. The cathode and the second grid are subjected to a potential difference of several kilovolts, somewhat lower than the breakdown voltage. The first cathode-grid space serves as an electron source under the action of the low-energy X- or {gamma}-ray photons. The cathode can also be plated with a metal of high Z, or a crystal scintillator connected to a photocathode can be used. After suitable amplification, the sudden burst of charges due to electron multiplication in the Townsend avalanche produces a well localized spark with a delay of a fraction of a microsecond. The image is obtained with the aid of a camera whose shutter is permanently open. The second type of detector consists of a Csl (Tl) crystal connected to the photocathode of a Thomson tube, 20 cm in diam. and with electrostatic focusing. The image on the secondary screen of this tube is transferred by an optical device to the photocathode of a tube with parallel electric and magnetic field (manufactured by the English Electric Valve Company) and serving as shutter. Some of the light entering the optical device is received by a photomultiplier, which controls the opening of the shutter tube through an amplitude selector. This arrangement makes it possible to distinguish between the light due to the signal and that due to the noise of the Thomson tube. The shutter tube is opened only by the former. Since the shutter tube remains open for only an extremely short time, the signal-noise ratio of this detector arrangement is high enough to give an image on the end screen of the shutter tube using a

  13. Neutron cameras for ITER

    International Nuclear Information System (INIS)

    Johnson, L.C.; Barnes, C.W.; Batistoni, P.

    1998-01-01

    Neutron cameras with horizontal and vertical views have been designed for ITER, based on systems used on JET and TFTR. The cameras consist of fan-shaped arrays of collimated flight tubes, with suitably chosen detectors situated outside the biological shield. The sight lines view the ITER plasma through slots in the shield blanket and penetrate the vacuum vessel, cryostat, and biological shield through stainless steel windows. This paper analyzes the expected performance of several neutron camera arrangements for ITER. In addition to the reference designs, the authors examine proposed compact cameras, in which neutron fluxes are inferred from 16 N decay gammas in dedicated flowing water loops, and conventional cameras with fewer sight lines and more limited fields of view than in the reference designs. It is shown that the spatial sampling provided by the reference designs is sufficient to satisfy target measurement requirements and that some reduction in field of view may be permissible. The accuracy of measurements with 16 N-based compact cameras is not yet established, and they fail to satisfy requirements for parameter range and time resolution by large margins

  14. Dual-energy cone-beam CT with a flat-panel detector: Effect of reconstruction algorithm on material classification

    International Nuclear Information System (INIS)

    Zbijewski, W.; Gang, G. J.; Xu, J.; Wang, A. S.; Stayman, J. W.; Taguchi, K.; Carrino, J. A.; Siewerdsen, J. H.

    2014-01-01

    Purpose: Cone-beam CT (CBCT) with a flat-panel detector (FPD) is finding application in areas such as breast and musculoskeletal imaging, where dual-energy (DE) capabilities offer potential benefit. The authors investigate the accuracy of material classification in DE CBCT using filtered backprojection (FBP) and penalized likelihood (PL) reconstruction and optimize contrast-enhanced DE CBCT of the joints as a function of dose, material concentration, and detail size. Methods: Phantoms consisting of a 15 cm diameter water cylinder with solid calcium inserts (50–200 mg/ml, 3–28.4 mm diameter) and solid iodine inserts (2–10 mg/ml, 3–28.4 mm diameter), as well as a cadaveric knee with intra-articular injection of iodine were imaged on a CBCT bench with a Varian 4343 FPD. The low energy (LE) beam was 70 kVp (+0.2 mm Cu), and the high energy (HE) beam was 120 kVp (+0.2 mm Cu, +0.5 mm Ag). Total dose (LE+HE) was varied from 3.1 to 15.6 mGy with equal dose allocation. Image-based DE classification involved a nearest distance classifier in the space of LE versus HE attenuation values. Recognizing the differences in noise between LE and HE beams, the LE and HE data were differentially filtered (in FBP) or regularized (in PL). Both a quadratic (PLQ) and a total-variation penalty (PLTV) were investigated for PL. The performance of DE CBCT material discrimination was quantified in terms of voxelwise specificity, sensitivity, and accuracy. Results: Noise in the HE image was primarily responsible for classification errors within the contrast inserts, whereas noise in the LE image mainly influenced classification in the surrounding water. For inserts of diameter 28.4 mm, DE CBCT reconstructions were optimized to maximize the total combined accuracy across the range of calcium and iodine concentrations, yielding values of ∼88% for FBP and PLQ, and ∼95% for PLTV at 3.1 mGy total dose, increasing to ∼95% for FBP and PLQ, and ∼98% for PLTV at 15.6 mGy total dose. For a

  15. Breast Imaging Utilizing Dedicated Gamma Camera and (99m)Tc-MIBI: Experience at the Tel Aviv Medical Center and Review of the Literature Breast Imaging.

    Science.gov (United States)

    Even-Sapir, Einat; Golan, Orit; Menes, Tehillah; Weinstein, Yuliana; Lerman, Hedva

    2016-07-01

    The scope of the current article is the clinical role of gamma cameras dedicated for breast imaging and (99m)Tc-MIBI tumor-seeking tracer, as both a screening modality among a healthy population and as a diagnostic modality in patients with breast cancer. Such cameras are now commercially available. The technology utilizing a camera composed of a NaI (Tl) detector is termed breast-specific gamma imaging. The technology of dual-headed camera composed of semiconductor cadmium zinc telluride detectors that directly converts gamma-ray energy into electronic signals is termed molecular breast imaging. Molecular breast imaging system has been installed at the Department of Nuclear medicine at the Tel Aviv Sourasky Medical Center, Tel Aviv in 2009. The article reviews the literature well as our own experience. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Small animals bone density and morphometry analysis with a dual energy X-rays absorptiometry bone densitometer using a 2D digital radiographic detector

    International Nuclear Information System (INIS)

    Boudousq, V.; Bordy, T.; Gonon, G.; Dinten, J.M.

    2004-01-01

    LEXXOS (DMS, Montpellier, France) is the first axial and total body cone beam bone densitometer using a 2D digital radiographic detector. In previous papers, technical principles and patients' Bone Mineral Density (BMD) measurement performances were presented. Bone densitometers are also used on small animals for drug development. In this presentation, we show how LEXXOS can be adapted for small animals' examinations and evaluate its performances. At first, in order to take advantage of the whole area of the 20 x 20 cm 2 digital radiographic detector, it has been made profit of X-Rays magnification by adapting the geometrical configuration. Secondly, as small animals present low BMD, a specific dual energy calibration has been defined. This adapted system has then been evaluated on two sets of mice: six reference mice and six ovariectomized mice. Each month, these two populations have been examined and the averaged total body BMD has been measured. This evaluation shows that the right order of BMD magnitude is obtained and, as expected, BMD increases on two sets until a period around puberty and the ovariectomized set presents a significant decrease after. Moreover, the bone image obtained by dual energy processing on LEXXOS presents a radiographic image quality providing useful complementary information on bone morphometry and architecture. This study shows that LEXXOS cone beam bone densitometer provides simultaneously useful quantitative and qualitative information for analysis of bone evolution on small animals. In the future, same system architecture and processing methodology can be used with higher resolution detectors in order to refine information on bone architecture. (authors)

  17. Gamma camera

    International Nuclear Information System (INIS)

    Tschunt, E.; Platz, W.; Baer, Ul; Heinz, L.

    1978-01-01

    A gamma camera has a plurality of exchangeable collimators, one of which is replaceably mounted in the ray inlet opening of the camera, while the others are placed on separate supports. Supports are swingably mounted upon a column one above the other

  18. Picosecond camera

    International Nuclear Information System (INIS)

    Decroisette, Michel

    A Kerr cell activated by infrared pulses of a model locked Nd glass laser, acts as an ultra-fast and periodic shutter, with a few p.s. opening time. Associated with a S.T.L. camera, it gives rise to a picosecond camera allowing us to study very fast effects [fr

  19. Scanning gamma camera

    International Nuclear Information System (INIS)

    Engdahl, L.W.; Batter, J.F. Jr.; Stout, K.J.

    1977-01-01

    A scanning system for a gamma camera providing for the overlapping of adjacent scan paths is described. A collimator mask having tapered edges provides for a graduated reduction in intensity of radiation received by a detector thereof, the reduction in intensity being graduated in a direction normal to the scanning path to provide a blending of images of adjacent scan paths. 31 claims, 15 figures

  20. Comparison of Anger camera and BGO mosaic position-sensitive detectors for `Super ACAR`. Precision electron momentum densities via angular correlation of annihilation radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mills, A.P. Jr. [Bell Labs. Murray Hill, NJ (United States); West, R.N.; Hyodo, Toshio

    1997-03-01

    We discuss the relative merits of Anger cameras and Bismuth Germanate mosaic counters for measuring the angular correlation of positron annihilation radiation at a facility such as the proposed Positron Factory at Takasaki. The two possibilities appear equally cost effective at this time. (author)

  1. Analyzer for gamma cameras diagnostic

    International Nuclear Information System (INIS)

    Oramas Polo, I.; Osorio Deliz, J. F.; Diaz Garcia, A.

    2013-01-01

    This research work was carried out to develop an analyzer for gamma cameras diagnostic. It is composed of an electronic system that includes hardware and software capabilities, and operates from the acquisition of the 4 head position signals of a gamma camera detector. The result is the spectrum of the energy delivered by nuclear radiation coming from the camera detector head. This system includes analog processing of position signals from the camera, digitization and the subsequent processing of the energy signal in a multichannel analyzer, sending data to a computer via a standard USB port and processing of data in a personal computer to obtain the final histogram. The circuits are composed of an analog processing board and a universal kit with micro controller and programmable gate array. (Author)

  2. Collimator changer for scintillation camera

    International Nuclear Information System (INIS)

    Jupa, E.C.; Meeder, R.L.; Richter, E.K.

    1976-01-01

    A collimator changing assembly mounted on the support structure of a scintillation camera is described. A vertical support column positioned proximate the detector support column with a plurality of support arms mounted thereon in a rotatable cantilevered manner at separate vertical positions. Each support arm is adapted to carry one of the plurality of collimators which are interchangeably mountable on the underside of the detector and to transport the collimator between a store position remote from the detector and a change position underneath said detector

  3. Gamma camera

    International Nuclear Information System (INIS)

    Tschunt, E.; Platz, W.; Baer, U.; Heinz, L.

    1978-01-01

    A gamma camera has a plurality of exchangeable collimators, one of which is mounted in the ray inlet opening of the camera, while the others are placed on separate supports. The supports are swingably mounted upon a column one above the other through about 90 0 to a collimator exchange position. Each of the separate supports is swingable to a vertically aligned position, with limiting of the swinging movement and positioning of the support at the desired exchange position. The collimators are carried on the supports by means of a series of vertically disposed coil springs. Projections on the camera are movable from above into grooves of the collimator at the exchange position, whereupon the collimator is turned so that it is securely prevented from falling out of the camera head

  4. Gamma camera system

    International Nuclear Information System (INIS)

    Miller, D.W.; Gerber, M.S.

    1977-01-01

    A gamma camera system having control components operating in conjunction with a solid state detector is described. The detector is formed of a plurality of discrete components which are associated in geometrical or coordinate arrangement defining a detector matrix to derive coordinate signal outputs. These outputs are selectively filtered and summed to form coordinate channel signals and corresponding energy channel signals. A control feature of the invention regulates the noted summing and filtering performance to derive data acceptance signals which are addressed to further treating components. The latter components include coordinate and enery channel multiplexers as well as energy-responsive selective networks. A sequential control is provided for regulating the signal processing functions of the system to derive an overall imaging cycle

  5. Semiconductor Detectors

    International Nuclear Information System (INIS)

    Cortina, E.

    2007-01-01

    Particle detectors based on semiconductor materials are among the few devices used for particle detection that are available to the public at large. In fact we are surrounded by them in our daily lives: they are used in photoelectric cells for opening doors, in digital photographic and video camera, and in bar code readers at supermarket cash registers. (Author)

  6. Split detector

    International Nuclear Information System (INIS)

    Cederstrand, C.N.; Chism, H.R.

    1982-01-01

    A gas analyzer is disclosed which provides a dual channel capability for the simultaneous determination of the presence and concentration of two gases in a stream of sample gas and which has a single infrared source, a single sample cell, two infrared bandpass filters, and two infrared detectors. A separator between the filters and detectors prevents interchange of radiation between the filters. The separator is positioned by fitting it in a slot

  7. Temporal resolution measurement of 128-slice dual source and 320-row area detector computed tomography scanners in helical acquisition mode using the impulse method.

    Science.gov (United States)

    Hara, Takanori; Urikura, Atsushi; Ichikawa, Katsuhiro; Hoshino, Takashi; Nishimaru, Eiji; Niwa, Shinji

    2016-04-01

    To analyse the temporal resolution (TR) of modern computed tomography (CT) scanners using the impulse method, and assess the actual maximum TR at respective helical acquisition modes. To assess the actual TR of helical acquisition modes of a 128-slice dual source CT (DSCT) scanner and a 320-row area detector CT (ADCT) scanner, we assessed the TRs of various acquisition combinations of a pitch factor (P) and gantry rotation time (R). The TR of the helical acquisition modes for the 128-slice DSCT scanner continuously improved with a shorter gantry rotation time and greater pitch factor. However, for the 320-row ADCT scanner, the TR with a pitch factor of pitch factor of >1.0, it was approximately one half of the gantry rotation time. The maximum TR values of single- and dual-source helical acquisition modes for the 128-slice DSCT scanner were 0.138 (R/P=0.285/1.5) and 0.074s (R/P=0.285/3.2), and the maximum TR values of the 64×0.5- and 160×0.5-mm detector configurations of the helical acquisition modes for the 320-row ADCT scanner were 0.120 (R/P=0.275/1.375) and 0.195s (R/P=0.3/0.6), respectively. Because the TR of a CT scanner is not accurately depicted in the specifications of the individual scanner, appropriate acquisition conditions should be determined based on the actual TR measurement. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  8. The Sydney University PAPA camera

    Science.gov (United States)

    Lawson, Peter R.

    1994-04-01

    The Precision Analog Photon Address (PAPA) camera is a photon-counting array detector that uses optical encoding to locate photon events on the output of a microchannel plate image intensifier. The Sydney University camera is a 256x256 pixel detector which can operate at speeds greater than 1 million photons per second and produce individual photon coordinates with a deadtime of only 300 ns. It uses a new Gray coded mask-plate which permits a simplified optical alignment and successfully guards against vignetting artifacts.

  9. A novel detector based on dual-mode fiber polished half block's characteristics for sensitive monitorings of radiation and materials

    International Nuclear Information System (INIS)

    Saeed, Ghadirli

    2005-01-01

    Full text : The overlay index dependence characteristics of the power distribution between two modes of dual-mode fiber polished half blocks is studied. The heat dependence characteristics of a certain overlay index affects the modal power distributions at the input of interferometer sensors used for monitoring the sensitive heat radiation changes. The other fundamental applications such as material recognitions through the index dependence characteristics in the closed chambers is also suggested

  10. Control system for gamma camera

    International Nuclear Information System (INIS)

    Miller, D.W.

    1977-01-01

    An improved gamma camera arrangement is described which utilizing a solid state detector, formed of high purity germanium. the central arrangement of the camera operates to effect the carrying out of a trapezoidal filtering operation over antisymmetrically summed spatial signals through gated integration procedures utilizing idealized integrating intervals. By simultaneously carrying out peak energy evaluation of the input signals, a desirable control over pulse pile-up phenomena is achieved. Additionally, through the use of the time derivative of incoming pulse or signal energy information to initially enable the control system, a low level information evaluation is provided serving to enhance the signal processing efficiency of the camera

  11. Impact of reduced-radiation dual-energy protocols using 320-detector row computed tomography for analyzing urinary calculus components: initial in vitro evaluation.

    Science.gov (United States)

    Cai, Xiangran; Zhou, Qingchun; Yu, Juan; Xian, Zhaohui; Feng, Youzhen; Yang, Wencai; Mo, Xukai

    2014-10-01

    To evaluate the impact of reduced-radiation dual-energy (DE) protocols using 320-detector row computed tomography on the differentiation of urinary calculus components. A total of 58 urinary calculi were placed into the same phantom and underwent DE scanning with 320-detector row computed tomography. Each calculus was scanned 4 times with the DE protocols using 135 kV and 80 kV tube voltage and different tube current combinations, including 100 mA and 570 mA (group A), 50 mA and 290 mA (group B), 30 mA and 170 mA (group C), and 10 mA and 60 mA (group D). The acquisition data of all 4 groups were then analyzed by stone DE analysis software, and the results were compared with x-ray diffraction analysis. Noise, contrast-to-noise ratio, and radiation dose were compared. Calculi were correctly identified in 56 of 58 stones (96.6%) using group A and B protocols. However, only 35 stones (60.3%) and 16 stones (27.6%) were correctly diagnosed using group C and D protocols, respectively. Mean noise increased significantly and mean contrast-to-noise ratio decreased significantly from groups A to D (P calculus component analysis while reducing patient radiation exposure to 1.81 mSv. Further reduction of tube currents may compromise diagnostic accuracy. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Image quality and radiation dose of lower extremity CT angiography at 70 kVp on an integrated circuit detector dual-source computed tomography.

    Science.gov (United States)

    Qi, Li; Zhao, Yan'E; Zhou, Chang Sheng; Spearman, James V; Renker, Matthias; Schoepf, U Joseph; Zhang, Long Jiang; Lu, Guang Ming

    2015-06-01

    Despite the well-established requirement for radiation dose reduction there are few studies examining the potential for lower extremity CT angiography (CTA) at 70 kVp. To compare the image quality and radiation dose of lower extremity CTA at 70 kVp using a dual-source CT system with an integrated circuit detector to similar studies at 120 kVp. A total of 62 patients underwent lower extremity CTA. Thirty-one patients were examined at 70 kVp using a second generation dual-source CT with an integrated circuit detector (70 kVp group) and 31 patients were evaluated at 120 kVp using a first generation dual-source CT (120 kVp group). The attenuation and image noise were measured and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Two radiologists assessed image quality. Radiation dose was compared. The mean attenuation of the 70 kVp group was higher than the 120 kVp group (575 ± 149 Hounsfield units [HU] vs. 258 ± 38 HU, respectively, P < 0.001) as was SNR (44.0 ± 22.0 vs 32.7 ± 13.3, respectively, P = 0.017), CNR (39.7 ± 20.6 vs 26.6 ± 11.7, respectively, P = 0.003) and the mean image quality score (3.7 ± 0.1 vs. 3.2 ± 0.3, respectively, P < 0.001). The inter-observer agreement was good for the 70 kVp group and moderate for the 120 kVp group. The dose-length product was lower in the 70 kVp group (264.5 ± 63.1 mGy × cm vs. 412.4 ± 81.5 mGy × cm, P < 0.001). Lower extremity CTA at 70 kVp allows for lower radiation dose with higher SNR, CNR, and image quality when compared with standard 120 kVp. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  13. Quantifying metal artefact reduction using virtual monochromatic dual-layer detector spectral CT imaging in unilateral and bilateral total hip prostheses

    Energy Technology Data Exchange (ETDEWEB)

    Wellenberg, R.H.H., E-mail: r.h.wellenberg@amc.uva.nl [Department of Radiology, Academic Medical Centre, Amsterdam (Netherlands); Boomsma, M.F., E-mail: m.f.boomsma@isala.nl [Department of Radiology, Isala, Zwolle (Netherlands); Osch, J.A.C. van, E-mail: j.a.c.van.osch@isala.nl [Department of Radiology, Isala, Zwolle (Netherlands); Vlassenbroek, A., E-mail: alain.vlassenbroek@philips.com [Philips Medical Systems, Brussels (Belgium); Milles, J., E-mail: julien.milles@philips.com [Philips Medical Systems, Eindhoven (Netherlands); Edens, M.A., E-mail: m.a.edens@isala.nl [Department of Innovation and Science, Isala, Zwolle (Netherlands); Streekstra, G.J., E-mail: g.j.streekstra@amc.uva.nl [Department of Radiology, Academic Medical Centre, Amsterdam (Netherlands); Slump, C.H., E-mail: c.h.slump@utwente.nl [MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede (Netherlands); Maas, M., E-mail: m.maas@amc.uva.nl [Department of Radiology, Academic Medical Centre, Amsterdam (Netherlands)

    2017-03-15

    Highlights: • Dual-layer detector CT reduces metal artefacts at high monochromatic energies (keV). • 130 keV images were optimal based on quantitative analysis on CNRs. • Optimal keVs varied from 74 to 150 keV for different hip prostheses configurations. • The Titanium alloy resulted in less severe artefacts compared to the Cobalt alloy. • Severe metal artefacts, caused by extensive photon-starvation, were not reduced. - Abstract: Purpose: To quantify the impact of prosthesis material and design on the reduction of metal artefacts in total hip arthroplasties using virtual monochromatic dual-layer detector Spectral CT imaging. Methods: The water-filled total hip arthroplasty phantom was scanned on a novel 128-slice Philips IQon dual-layer detector Spectral CT scanner at 120-kVp and 140-kVp at a standard computed tomography dose index of 20.0 mGy. Several unilateral and bilateral hip prostheses consisting of different metal alloys were inserted and combined which were surrounded by 18 hydroxyapatite calcium carbonate pellets representing bone. Images were reconstructed with iterative reconstruction and analysed at monochromatic energies ranging from 40 to 200 keV. CT numbers in Hounsfield Units (HU), noise measured as the standard deviation in HU, signal-to-noise-ratios (SNRs) and contrast-to-noise-ratios (CNRs) were analysed within fixed regions-of-interests placed in and around the pellets. Results: In 70 and 74 keV virtual monochromatic images the CT numbers of the pellets were similar to 120-kVp and 140-kVp polychromatic results, therefore serving as reference. A separation into three categories of metal artefacts was made (no, mild/moderate and severe) where pellets were categorized based on HU deviations. At high keV values overall image contrast was reduced. For mild/moderate artefacts, the highest average CNRs were attained with virtual monochromatic 130 keV images, acquired at 140-kVp. Severe metal artefacts were not reduced. In 130 keV images

  14. Characterisation of Low Frequency Gravitational Waves from Dual RF Coaxial-Cable Detector: Fractal Textured Dynamical 3-Space

    OpenAIRE

    Cahill, Reginald T.

    2012-01-01

    Experiments have revealed that the Fresnel drag effect is not present in RF coaxial cables, contrary to a previous report. This enables a very sensitive, robust and compact detector, that is 1st order in v / c and using one clock, to detect the dynamical space passing the earth, revealing the sidereal rotation of the earth, together with significant wave / turbulence e ff ects. These are “gravitational waves”, and previously detected by Cahill ...

  15. Gamma ray camera

    International Nuclear Information System (INIS)

    Wang, S.-H.; Robbins, C.D.

    1979-01-01

    An Anger gamma ray camera is improved by the substitution of a gamma ray sensitive, proximity type image intensifier tube for the scintillator screen in the Anger camera. The image intensifier tube has a negatively charged flat scintillator screen, a flat photocathode layer, and a grounded, flat output phosphor display screen, all of which have the same dimension to maintain unit image magnification; all components are contained within a grounded metallic tube, with a metallic, inwardly curved input window between the scintillator screen and a collimator. The display screen can be viewed by an array of photomultipliers or solid state detectors. There are two photocathodes and two phosphor screens to give a two stage intensification, the two stages being optically coupled by a light guide. (author)

  16. Experience with dedicated ultra fast solid state cardiac gamma camera: technologist perspective

    International Nuclear Information System (INIS)

    Parab, Anil; Gaikar, Anil; Patil, Kashinath; Lele, V.

    2010-01-01

    Full text: To describe technologist perspective of working with ultra fast solid state gamma camera and comparison with conventional dual head gamma camera. Material and Methods: 900 Myocardial Perfusion scan were carried out on dedicated solid state detector cardiac camera between 1st February 2010 till 29th August 2010. 27 studies were done back to back on a conventional dual head gamma camera. In 2 cases dual head isotope imaging was done (Thallium+ 99m Tc-tetrofosmin). Rest stress protocol was used in 600 patients and stress - rest protocol was used in 300. 1:3 ratio of injected activity was maintained for both protocols (5 mCi for 1st study and 15 mCi for second study). For Rest - Stress protocol, 5 mCi of 99m Tc - Tetrofosmin was injected at rest, 40 minutes later, 5 min image was acquired on the solid state detector. Patient was then stressed. 15 mCi 99m Tc - Tetrofosmin was injected at peak stress. Images were acquired 20 minutes later for 3 minutes (total duration of study 90-100 min). For stress rest protocol, 5 mCi 99m Tc - Tetrofosmin was injected at peak stress. 5 mCi images were acquired 20 minutes later. Rest injection of 15 mCi was given 1 hour post stress injection. Rest images were acquired 40 minutes after rest injection (total duration of study 110-120 min). Results: We observed even with lesser amount activity and acquisition time of 5 min/cardiac scan it showed high sensitivity count rate over 2.2-4.7 kcps (10 times more counts than standard gamma camera). System gives better energy resolution < 7%. Better image contrast. Dual isotope imaging can be possible. Spatial resolution 4.3-4.9 mm. Excellent quality images were obtained using low activities (5 mCi/15 mCi) using 1/3rd the acquisition time compared to conventional dual head gamma camera Even in obese patients 7 mCi/21 mCi activity yielded excellent images at 1/3 rd acquisition time Quick acquisition resulted in greater patient comfort and no motion artifact also due to non rotation of

  17. Optimization of the integration time of pulse shape analysis for dual-layer GSO detector with different amount of Ce

    International Nuclear Information System (INIS)

    Yamamoto, Seiichi

    2008-01-01

    For a multi-layer depth-of-interaction (DOI) detector using different decay times, pulse shape analysis based on two different integration times is often used to distinguish scintillators in DOI direction. This method measures a partial integration and a full integration, and calculates the ratio of these two to obtain the pulse shape distribution. The full integration time is usually set to integrate full width of the scintillation pulse. However, the optimum partial integration time is not obvious for obtaining the best separation of the pulse shape distribution. To make it clear, a theoretical analysis and experiments were conducted for pulse shape analysis by changing the partial integration time using a scintillation detector of GSOs with different amount of Ce. A scintillation detector with 1-in. round photomultiplier tube (PMT) optically coupled GSO of 1.5 mol% (decay time: 35 ns) and that of 0.5 mol% (decay time: 60 ns) was used for the experiments. The signal from PMT was digitally integrated with partial (50-150 ns) and full (160 ns) integration times and ratio of these two was calculated to obtain the pulse shape distribution. In the theoretical analysis, partial integration time of 50 ns showed largest distance between two peaks of the pulse shape distribution. In the experiments, it showed maximum at 70-80 ns of partial integration time. The peak to valley ratio showed the maximum at 120-130 ns. Because the separation of two peaks is determined by the peak to valley ratio, we conclude the optimum partial integration time for these combinations of GSOs is around 120-130 ns, relatively longer than the expected value

  18. WE-AB-303-01: FEATURED PRESENTATION: A Dual-Detector Phase-Matched Digital Tomosynthesis (DTS) Imaging Scheme Using Aggregated KV and MV Projections for Intra-Treatment Lung Tumor Tracking

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y; Yin, F; Mao, R; Gao, R; Ren, L [Duke University Medical Center, Durham, NC (United States)

    2015-06-15

    Purpose: To develop a dual-detector phase-matched DTS technique for continuous and fast intra-treatment lung tumor localization. Methods: Tumor localization accuracy of limited-angle DTS imaging is affected by low inter-slice resolution. The dual-detector DTS technique aims to overcome this limitation through combining orthogonally acquired beam’s eye view MV projections and kV projections for intra-treatment DTS reconstruction and localization. To aggregate the kV and MV projections for reconstruction, the MV projections were linearly converted to synthesize corresponding kV projections. To further address the lung motion induced localization errors, this technique uses respiratory phase-matching to match the motion information between on-board DTS and reference DTS to offset the adverse effects of motion blurriness in tumor localization.A study was performed using the CIRS008A lung phantom to simulate different on-board target variation scenarios for localization. The intra-treatment kV and MV acquisition was achieved through the Varian TrueBeam Developer Mode. Four methods were compared for their localization accuracy: 1. the proposed dual-detector phase-matched DTS technique; 2. the single-detector phase-matched DTS technique; 3. the dual-detector 3D-DTS technique without phase-matching; and 4. the single-detector 3D-DTS technique without phase-matching. Results: For scan angles of 2.5°, 5°, 10°, 20° and 30°, the dual-detector phase-matched DTS technique localized the tumor with average(±standard deviations) errors of 0.4±0.3 mm, 0.5±0.3 mm, 0.6±0.2 mm, 0.9±0.4 mm and 1.0±0.3 mm, respectively. The corresponding values of single-detector phase-matched DTS technique were 4.0±2.5 mm, 2.7±1.1 mm, 1.7±1.2 mm, 2.2±0.9 mm and 1.5±0.8 mm, respectively. The values of dual-detector 3D-DTS technique were 6.2±1.7 mm, 6.3±1.2 mm, 5.3±1.3 mm, 2.0±2.2 mm and 1.5±0.5 mm, respectively. And the values of single-detector 3D-DTS technique were 9.7±8.9 mm, 9

  19. ProtoDUNE-DP---PROTOtype for the Deep Underground Neutrino Experiment - Dual Phase detector (Electrostatic Simulations and Performance Studies)

    CERN Document Server

    Chiu, Pin-Jung

    In search of answers to the biggest missing puzzle in the field of neutrino physics, large- scale Liquid Argon Time Projection Chambers (LAr-TPCs) have been postulated to be the most attractive instruments for next generation neutrino observations. A state-of-the- art experiment, the Deep Underground Neutrino Experiment (DUNE), which will utilize this LAr-TPC technology for the studies of neutrino science and proton decay, is currently in the stage of design and prototyping. This thesis reports on the behavior studies of a 6 × 6 × 6 m^3 prototype, ProtoDUNE, in the context of DUNE from the electrostatic’s point of view. Electrostatic simulations had been performed on the whole detector in order to verify the uniformity of the electric field, and to assure that all local electric fields within the detector are below a certain value to avoid any electrical breakdown phenomena. Additionally, to characterize the performance of the 2D anode used for charge readout in the experiment, some simulations and measur...

  20. An imaging system for a gamma camera

    International Nuclear Information System (INIS)

    Miller, D.W.; Gerber, M.S.

    1980-01-01

    A detailed description is given of a novel gamma camera which is designed to produce superior images than conventional cameras used in nuclear medicine. The detector consists of a solid state detector (e.g. germanium) which is formed to have a plurality of discrete components to enable 2-dimensional position identification. Details of the electronic processing circuits are given and the problems and limitations introduced by noise are discussed in full. (U.K.)

  1. Pre-chemotherapy values for left and right ventricular volumes and ejection fraction by gated tomographic radionuclide angiography using a cadmium-zinc-telluride detector gamma camera

    DEFF Research Database (Denmark)

    Haarmark, Christian; Haase, Christine; Jensen, Maria Maj

    2016-01-01

    age and both left and right ventricular volumes in women (r = -0.4, P right end systolic ventricular volume in men (r = -0.3, P = .001). CONCLUSION: A set of reference values for cardiac evaluation prior to chemotherapy in cancer patients without other known cardiopulmonary......BACKGROUND: Estimation of left ventricular ejection fraction (LVEF) using equilibrium radionuclide angiography is an established method for assessment of left ventricular function. The purpose of this study was to establish normative data on left and right ventricular volumes and ejection fraction......, using cadmium-zinc-telluride SPECT camera. METHODS AND RESULTS: From routine assessments of left ventricular function in 1172 patients, we included 463 subjects (194 men and 269 women) without diabetes, previous potentially cardiotoxic chemotherapy, known cardiovascular or pulmonary disease. The lower...

  2. 18F-FDG imaging with a coincidence dual-headed gamma camera (Co-PET) in the diagnosis, staging and management of lung cancer

    International Nuclear Information System (INIS)

    Lin, P.; Chu, J.; Pocock, N.; Quach, T.; Sorensen, B.

    1999-01-01

    Full text: FDG-PET has an established role in the management of lung cancer, while the experience with FDG-Co-PET is limited. Our study aims to demonstrate the feasibility of Co-PET in staging and management of lung cancer. Thirty-nine Co-PET studies were performed on our first 36 patients (pts) with primary lung cancer between November 1997 and October 1998. Tomography of brain and torso with an ADAC Solus MCD gamma camera was performed (60 min after 200 MBq of 18 FFDG and > 6 h fasting). Histology subgroups included squamous (14 pts), small cell (1), adeno-carcinoma (11), broncho-alveolar (1), large cell (8), carcinoid (1). CT/clinical staging subgroups included 18 pts in stage 1, 4 in stage 2, 7 in stage 3a, 2 in stage 3b, 8 in stage 4. Compared with CT/clinical staging, FDG upstaged 5 pts (14%) with regional nodal metastases (mets) and 8 pts (22%) with distant mets (cervical = 2, lung = 1, brain = 3, bone = 3, abdomen = 4). FDG under-staged 2 pts in 3 sites (all < 15 mm). Surgical nodal staging was performed in 14 pts: false-positives occurred in 3 CT and 1 Co-PET studies, and false-negatives in one CT/Co-PET. Site sensitivities for primary (smallest 7 mm) and regional lymph nodes are 100% and 88% respectively. Specificities for primary and regional nodes are 100% and 96% respectively. Co-PET also has impact on management: treatment intent (6 pts), radiotherapy fields (1), diagnosis of lung mets (2) and radiation pneumonitis (1). In conclusion, our initial data demonstrate FDG-Co-PET scanning could provide a valuable addition to conventional imaging studies in diagnosis, staging and management of lung cancer

  3. Image quality characteristics for virtual monoenergetic images using dual-layer spectral detector CT: Comparison with conventional tube-voltage images.

    Science.gov (United States)

    Sakabe, Daisuke; Funama, Yoshinori; Taguchi, Katsuyuki; Nakaura, Takeshi; Utsunomiya, Daisuke; Oda, Seitaro; Kidoh, Masafumi; Nagayama, Yasunori; Yamashita, Yasuyuki

    2018-05-01

    To investigate the image quality characteristics for virtual monoenergetic images compared with conventional tube-voltage image with dual-layer spectral CT (DLCT). Helical scans were performed using a first-generation DLCT scanner, two different sizes of acrylic cylindrical phantoms, and a Catphan phantom. Three different iodine concentrations were inserted into the phantom center. The single-tube voltage for obtaining virtual monoenergetic images was set to 120 or 140 kVp. Conventional 120- and 140-kVp images and virtual monoenergetic images (40-200-keV images) were reconstructed from slice thicknesses of 1.0 mm. The CT number and image noise were measured for each iodine concentration and water on the 120-kVp images and virtual monoenergetic images. The noise power spectrum (NPS) was also calculated. The iodine CT numbers for the iodinated enhancing materials were similar regardless of phantom size and acquisition method. Compared with the iodine CT numbers of the conventional 120-kVp images, those for the monoenergetic 40-, 50-, and 60-keV images increased by approximately 3.0-, 1.9-, and 1.3-fold, respectively. The image noise values for each virtual monoenergetic image were similar (for example, 24.6 HU at 40 keV and 23.3 HU at 200 keV obtained at 120 kVp and 30-cm phantom size). The NPS curves of the 70-keV and 120-kVp images for a 1.0-mm slice thickness over the entire frequency range were similar. Virtual monoenergetic images represent stable image noise over the entire energy spectrum and improved the contrast-to-noise ratio than conventional tube voltage using the dual-layer spectral detector CT. Copyright © 2018 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  4. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    A positron emission tomography camera having a plurality of detector planes positioned side-by-side around a patient area to detect radiation. Each plane includes a plurality of photomultiplier tubes and at least two rows of scintillation crystals on each photomultiplier tube extend across to adjacent photomultiplier tubes for detecting radiation from the patient area. Each row of crystals on each photomultiplier tube is offset from the other rows of crystals, and the area of each crystal on each tube in each row is different than the area of the crystals on the tube in other rows for detecting which crystal is actuated and allowing the detector to detect more inter-plane slides. The crystals are offset by an amount equal to the length of the crystal divided by the number of rows. The rows of crystals on opposite sides of the patient may be rotated 90 degrees relative to each other

  5. Principle of some gamma cameras (efficiencies, limitations, development)

    International Nuclear Information System (INIS)

    Allemand, R.; Bourdel, J.; Gariod, R.; Laval, M.; Levy, G.; Thomas, G.

    1975-01-01

    The quality of scintigraphic images is shown to depend on the efficiency of both the input collimator and the detector. Methods are described by which the quality of these images may be improved by adaptations to either the collimator (Fresnel zone camera, Compton effect camera) or the detector (Anger camera, image amplification camera). The Anger camera and image amplification camera are at present the two main instruments whereby acceptable space and energy resolutions may be obtained. A theoretical comparative study of their efficiencies is carried out, independently of their technological differences, after which the instruments designed or under study at the LETI are presented: these include the image amplification camera, the electron amplifier tube camera using a semi-conductor target CdTe and HgI 2 detector [fr

  6. Scintillating camera

    International Nuclear Information System (INIS)

    Vlasbloem, H.

    1976-01-01

    The invention relates to a scintillating camera and in particular to an apparatus for determining the position coordinates of a light pulse emitting point on the anode of an image intensifier tube which forms part of a scintillating camera, comprising at least three photomultipliers which are positioned to receive light emitted by the anode screen on their photocathodes, circuit means for processing the output voltages of the photomultipliers to derive voltages that are representative of the position coordinates; a pulse-height discriminator circuit adapted to be fed with the sum voltage of the output voltages of the photomultipliers for gating the output of the processing circuit when the amplitude of the sum voltage of the output voltages of the photomultipliers lies in a predetermined amplitude range, and means for compensating the distortion introduced in the image on the anode screen

  7. Improved positron emission tomography camera

    International Nuclear Information System (INIS)

    Mullani, N.A.

    1986-01-01

    A positron emission tomography camera having a plurality of rings of detectors positioned side-by-side or offset by one-half of the detector cross section around a patient area to detect radiation therefrom, and a plurality of scintillation crystals positioned relative to the photomultiplier tubes whereby each tube is responsive to more than one crystal. Each alternate crystal in the ring may be offset by one-half or less of the thickness of the crystal such that the staggered crystals are seen by more than one photomultiplier tube. This sharing of crystals and photomultiplier tubes allows identification of the staggered crystal and the use of smaller detectors shared by larger photomultiplier tubes thereby requiring less photomultiplier tubes, creating more scanning slices, providing better data sampling, and reducing the cost of the camera. (author)

  8. Gamma camera

    International Nuclear Information System (INIS)

    Reiss, K.H.; Kotschak, O.; Conrad, B.

    1976-01-01

    A gamma camera with a simplified setup as compared with the state of engineering is described permitting, apart from good localization, also energy discrimination. Behind the usual vacuum image amplifier a multiwire proportional chamber filled with trifluorine bromium methane is connected in series. Localizing of the signals is achieved by a delay line, energy determination by means of a pulse height discriminator. With the aid of drawings and circuit diagrams, the setup and mode of operation are explained. (ORU) [de

  9. Gamma camera

    International Nuclear Information System (INIS)

    Berninger, W.H.

    1975-01-01

    The light pulse output of a scintillator, on which incident collimated gamma rays impinge, is detected by an array of photoelectric tubes each having a convexly curved photocathode disposed in close proximity to the scintillator. Electronic circuitry connected to outputs of the phototubes develops the scintillation event position coordinate electrical signals with good linearity and with substantial independence of the spacing between the scintillator and photocathodes so that the phototubes can be positioned as close to the scintillator as is possible to obtain less distortion in the field of view and improved spatial resolution as compared to conventional planar photocathode gamma cameras

  10. Radioisotope camera

    International Nuclear Information System (INIS)

    Tausch, L.M.; Kump, R.J.

    1978-01-01

    The electronic ciruit corrects distortions caused by the distance between the individual photomultiplier tubes of the multiple radioisotope camera on one hand and between the tube configuration and the scintillator plate on the other. For this purpose the transmission characteristics of the nonlinear circuits are altered as a function of the energy of the incident radiation. By this means the threshold values between lower and higher amplification are adjusted to the energy level of each scintillation. The correcting circuit may be used for any number of isotopes to be measured. (DG) [de

  11. Development of a portable X-ray and gamma-ray detector instrument and imaging camera for use in radioactive and hazardous materials management

    International Nuclear Information System (INIS)

    Scyoc, J.M. van; James, R.B.; Anderson, R.J.

    1997-08-01

    The overall goal of this LDRD project was to develop instruments for use in the management of radioactive and hazardous wastes. Devices for identifying and imaging such wastes are critical to developing environmental remediation strategies. Field portable units are required to enable the on-site analysis of solids, liquids, and gas effluents. Red mercuric iodide (α-HgI 2 ) is a semiconductor material that can be operated as a high-energy-resolution radiation detector at ambient temperatures. This property provides the needed performance of conventional germanium- and silicon-based devices, while eliminating the need for the cryogenic cooling of such instruments. The first year of this project focused on improving the materials properties of the mercuric iodide to enable the new sensor technology; in particular the charge carrier traps limiting device performance were determined and eliminated. The second year involved the development of a field portable x-ray fluorescence analyzer for compositional analyses. The third and final year of the project focused on the development of imaging sensors to provide the capability for mapping the composition of waste masses. This project resulted in instruments useful not only for managing hazardous and radioactive wastes, but also in a variety of industrial and national security applications

  12. General Astrophysics with the HabEx Workhorse Camera

    Science.gov (United States)

    Stern, Daniel; Clarke, John; Gaudi, B. Scott; Kiessling, Alina; Krause, Oliver; Martin, Stefan; Scowen, Paul; Somerville, Rachel; HabEx STDT

    2018-01-01

    The Habitable Exoplanet Imaging Mission (HabEx) concept has been designed to enable an extensive suite of science, broadly put under the rubric of General Astrophysics, in addition to its exoplanet direct imaging science. General astrophysics directly addresses multiple NASA programmatic branches, and HabEx will enable investigations ranging from cosmology, to galaxy evolution, to stellar population studies, to exoplanet transit spectroscopy, to Solar System studies. This poster briefly describes one of the two primary HabEx General Astrophysics instruments, the HabEx Workhorse Camera (HWC). HWC will be a dual-detector UV-to-near-IR imager and multi-object grism spectrometer with a microshutter array and a moderate (3' x 3') field-of-view. We detail some of the key science we expect HWC to undertake, emphasizing unique capabilities enabled by a large-aperture, highly stable space-borne platform at these wavelengths.

  13. Analysis and modelling of the performance of a new solid-state detector in nuclear medicine: from Anger- to Semiconductor-detectors

    International Nuclear Information System (INIS)

    Imbert, L.

    2012-01-01

    Myocardial single-photon emission computed tomography (SPECT) is considered as the gold standard for the diagnosis of coronary artery disease. Developed in the 1980's with rotating Anger gamma cameras, this technique could be dramatically enhanced by new imaging systems working with semiconductor detectors and which performances are clearly enhanced. Two semiconductor cameras, dedicated to nuclear cardiology and equipped with Cadmium Zinc Telluride detectors, have been recently commercialized: the Discovery NM- 530c (General Electric) and the DSPECT (Spectrum Dynamics). The performances of these CZT cameras were compared: 1) by a comprehensive analysis of phantom and human SPECT images considered as normal and 2) with the parameters commonly recommended for SPECT recording and reconstruction. The results show the superiority of the CZT cameras in terms of detection sensitivity, spatial resolution and contrast-to-noise ratio, compared to conventional Anger cameras. These properties might lead to dramatically reduce acquisition times and/or the injected activities. However, the limits of these new CZT cameras, as well as the mechanism of certain artefacts, remain poorly known. This knowledge could be enhanced by a numerical modeling of the DSPECT camera, and this might also help to optimize acquisition and reconstruction parameters. We developed a simulator where the geometry of the detectors of the DSPECT camera and their energy response were modeled in the GATE platform. In order to validate this simulator, actually recorded data were compared with simulated data through three performance parameters: detection sensitivity, spatial resolution and energy resolution. Results were in agreement between simulated and actually recorded data. This observation validates the DSPECT simulator and opens the door to further studies planed to optimize the recorded and reconstruction processes, especially for complex protocols such as simultaneous dual-radionuclide acquisition

  14. Gamma camera system

    International Nuclear Information System (INIS)

    Miller, D.W.; Gerber, M.S.

    1982-01-01

    The invention provides a composite solid state detector for use in deriving a display, by spatial coordinate information, of the distribution or radiation emanating from a source within a region of interest, comprising several solid state detector components, each having a given surface arranged for exposure to impinging radiation and exhibiting discrete interactions therewith at given spatially definable locations. The surface of each component and the surface disposed opposite and substantially parallel thereto are associated with impedence means configured to provide for each opposed surface outputs for signals relating the given location of the interactions with one spatial coordinate parameter of one select directional sense. The detector components are arranged to provide groupings of adjacently disposed surfaces mutually linearly oriented to exhibit a common directional sense of the spatial coordinate parameter. Means interconnect at least two of the outputs associated with each of the surfaces within a given grouping for collecting the signals deriving therefrom. The invention also provides a camera system for imaging the distribution of a source of gamma radiation situated within a region of interest

  15. A novel PET camera calibration method

    International Nuclear Information System (INIS)

    Yerian, K.; Hartz, R.K.; Gaeta, J.M.; Marani, S.; Wong, W.H.; Bristow, D.; Mullani, N.A.

    1985-01-01

    Reconstructed time-of-flight PET images must be corrected for differences in the sensitivity of detector pairs, variations in the TOF gain between groups of detector pairs, and for shifts in the detector-pair timing windows. These calibration values are measured for each detector-pair coincidence line using a positron emitting ring source. The quality of the measured value for a detector pair depends on its statistics. To improve statistics, algorithms are developed which derive individual detector calibration values for efficiency, TOF offsets, and TOF fwhm from the raw detector-pair measurements. For the author's current TOFPET system there are 162,000 detector pairs which are reduced to 720 individual detector values. The data for individual detectors are subsequently recombined, improving the statistical quality of the resultant detector-pair values. In addition, storage requirements are significantly reduced by saving the individual detector values. These parameters are automatically evaluated on a routine basis and problem detectors reported for adjustment or replacement. Decomposing the detector-pair measurements into individual detector values significantly improves the calibration values used to correct camera artifacts in PET imaging

  16. High Frequency Design Considerations for the Large Detector Number and Small Form Factor Dual Electron Spectrometer of the Fast Plasma Investigation on NASA's Magnetospheric Multiscale Mission

    Science.gov (United States)

    Kujawski, Joseph T.; Gliese, Ulrik B.; Cao, N. T.; Zeuch, M. A.; White, D.; Chornay, D. J; Lobell, J. V.; Avanov, L. A.; Barrie, A. C.; Mariano, A. J.; hide

    2015-01-01

    Each half of the Dual Electron Spectrometer (DES) of the Fast Plasma Investigation (FPI) on NASA's Magnetospheric MultiScale (MMS) mission utilizes a microchannel plate Chevron stack feeding 16 separate detection channels each with a dedicated anode and amplifier/discriminator chip. The desire to detect events on a single channel with a temporal spacing of 100 ns and a fixed dead-time drove our decision to use an amplifier/discriminator with a very fast (GHz class) front end. Since the inherent frequency response of each pulse in the output of the DES microchannel plate system also has frequency components above a GHz, this produced a number of design constraints not normally expected in electronic systems operating at peak speeds of 10 MHz. Additional constraints are imposed by the geometry of the instrument requiring all 16 channels along with each anode and amplifier/discriminator to be packaged in a relatively small space. We developed an electrical model for board level interactions between the detector channels to allow us to design a board topology which gave us the best detection sensitivity and lowest channel to channel crosstalk. The amplifier/discriminator output was designed to prevent the outputs from one channel from producing triggers on the inputs of other channels. A number of Radio Frequency design techniques were then applied to prevent signals from other subsystems (e.g. the high voltage power supply, command and data handling board, and Ultraviolet stimulation for the MCP) from generating false events. These techniques enabled us to operate the board at its highest sensitivity when operated in isolation and at very high sensitivity when placed into the overall system.

  17. Detection of small pulmonary nodules on chest radiographs: efficacy of dual-energy subtraction technique using flat-panel detector chest radiography

    International Nuclear Information System (INIS)

    Oda, S.; Awai, K.; Funama, Y.; Utsunomiya, D.; Yanaga, Y.; Kawanaka, K.; Nakaura, T.; Hirai, T.; Murakami, R.; Nomori, H.; Yamashita, Y.

    2010-01-01

    Aim: To investigate the effect of a double-exposure dual-energy subtraction (DES) technique on the diagnostic performance of radiologists detecting small pulmonary nodules on flat-panel detector (FPD) chest radiographs. Materials and methods: Using FPD radiography 41 sets of chest radiographs were obtained from 26 patients with pulmonary nodules measuring ≤20 mm and from 15 normal participants. Each dataset included standard and corresponding DES images. There were six non-solid, 10 part-solid, and 10 solid nodules. The mean size of the 26 nodules was 15 ± 4.8 mm. Receiver operating characteristic (ROC) analysis was performed to compare the performance of the eight board-certified radiologists. Results: For the eight radiologists, the mean value of the area under the ROC curve (AUC) without and with DES images was 0.62 ± 0.05 and 0.68 ± 0.05, respectively; the difference was statistically significant (p = 0.02). For part-solid nodules, the difference of the mean AUC value was statistically significant (AUC = 0.61 ± 0.07 versus 0.69 ± 0.05; p < 0.01); for non-solid nodules it was not (AUC = 0.62 ± 0.1 versus 0.61 ± 0.09; p = 0.73), and for solid nodules it was not (AUC = 0.75 ± 0.1 versus 0.78 ± 0.08; p = 0.23). For nodules with overlapping bone shadows, the difference of the mean AUC value was statistically significant (p = 0.03), for nodules without overlapping, it was not (p = 0.26). Conclusion: Use of a double-exposure DES technique at FPD chest radiography significantly improved the diagnostic performance of radiologists to detect small pulmonary nodules.

  18. Dual recycling for GEO 600

    International Nuclear Information System (INIS)

    Grote, H; Freise, A; Malec, M; Heinzel, G; Willke, B; Lueck, H; Strain, K A; Hough, J; Danzmann, K

    2004-01-01

    Dual recycling is the combination of signal recycling and power recycling; both optical techniques improve the shot-noise-limited sensitivity of interferometric gravitational-wave detectors. In addition, signal recycling can reduce the loss of light power due to imperfect interference and allows us, in principle, to beat the standard quantum limit. The interferometric gravitational-wave detector GEO 600 is the first of the kilometre-scale detectors to use signal recycling. We have recently equipped the detector with a signal-recycling mirror with a transmittance of 1%. In this paper, we present details of the detector commissioning and the first locks of the dual-recycled interferometer

  19. Gamma camera

    International Nuclear Information System (INIS)

    Conrad, B.; Heinzelmann, K.G.

    1975-01-01

    A gamma camera is described which obviates the distortion of locating signals generally caused by the varied light conductive capacities of the light conductors in that the flow of light through each light conductor may be varied by means of a shutter. A balancing of the flow of light through each of the individual light conductors, in effect, collective light conductors may be balanced on the basis of their light conductive capacities or properties, so as to preclude a distortion of the locating signals caused by the varied light conductive properties of the light conductors. Each light conductor has associated therewith two, relative to each other, independently adjustable shutters, of which one forms a closure member and the other an adjusting shutter. In this embodiment of the invention it is thus possible to block all of the light conductors leading to a photoelectric transducer, with the exception of those light conductors which are to be balanced. The balancing of the individual light conductors may then be obtained on the basis of the output signals of the photoelectric transducer. (auth)

  20. Scintillation camera

    International Nuclear Information System (INIS)

    Zioni, J.; Klein, Y.; Inbar, D.

    1975-01-01

    The scintillation camera is to make pictures of the density distribution of radiation fields created by the injection or administration radioactive medicaments into the body of the patient. It contains a scintillation crystal, several photomultipliers and computer circuits to obtain an analytical function at the exits of the photomultiplier which is dependent on the position of the scintillations at the time in the crystal. The scintillation crystal is flat and spatially corresponds to the production site of radiation. The photomultipliers form a pattern whose basic form consists of at least three photomultipliers. They are assigned to at least two crossing parallel series groups where a vertical running reference axis in the crystal plane belongs to each series group. The computer circuits are each assigned to a reference axis. Each series of a series group assigned to one of the reference axes in the computer circuit has an adder to produce a scintillation dependent series signal. Furthermore, the projection of the scintillation on this reference axis is calculated. A series signal is used for this which originates from a series chosen from two neighbouring photomultiplier series of this group. The scintillation must have appeared between these chosen series. They are termed as basic series. The photomultiplier can be arranged hexagonally or rectangularly. (GG/LH) [de

  1. Single-acquisition method for simultaneous determination of extrinsic gamma-camera sensitivity and spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Santos, J.A.M. [Servico de Fisica Medica, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal)], E-mail: a.miranda@portugalmail.pt; Sarmento, S. [Servico de Fisica Medica, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal); Alves, P.; Torres, M.C. [Departamento de Fisica da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Bastos, A.L. [Servico de Medicina Nuclear, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal); Ponte, F. [Servico de Fisica Medica, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal)

    2008-01-15

    A new method for measuring simultaneously both the extrinsic sensitivity and spatial resolution of a gamma-camera in a single planar acquisition was implemented. A dual-purpose phantom (SR phantom; sensitivity/resolution) was developed, tested and the results compared with other conventional methods used for separate determination of these two important image quality parameters. The SR phantom yielded reproducible and accurate results, allowing an immediate visual inspection of the spatial resolution as well as the quantitative determination of the contrast for six different spatial frequencies. It also proved to be useful in the estimation of the modulation transfer function (MTF) of the image formation collimator/detector system at six different frequencies and can be used to estimate the spatial resolution as function of the direction relative to the digital matrix of the detector.

  2. Single-acquisition method for simultaneous determination of extrinsic gamma-camera sensitivity and spatial resolution

    International Nuclear Information System (INIS)

    Santos, J.A.M.; Sarmento, S.; Alves, P.; Torres, M.C.; Bastos, A.L.; Ponte, F.

    2008-01-01

    A new method for measuring simultaneously both the extrinsic sensitivity and spatial resolution of a gamma-camera in a single planar acquisition was implemented. A dual-purpose phantom (SR phantom; sensitivity/resolution) was developed, tested and the results compared with other conventional methods used for separate determination of these two important image quality parameters. The SR phantom yielded reproducible and accurate results, allowing an immediate visual inspection of the spatial resolution as well as the quantitative determination of the contrast for six different spatial frequencies. It also proved to be useful in the estimation of the modulation transfer function (MTF) of the image formation collimator/detector system at six different frequencies and can be used to estimate the spatial resolution as function of the direction relative to the digital matrix of the detector

  3. Gamma camera performance: technical assessment protocol

    Energy Technology Data Exchange (ETDEWEB)

    Bolster, A.A. [West Glasgow Hospitals NHS Trust, London (United Kingdom). Dept. of Clinical Physics; Waddington, W.A. [University College London Hospitals NHS Trust, London (United Kingdom). Inst. of Nuclear Medicine

    1996-12-31

    This protocol addresses the performance assessment of single and dual headed gamma cameras. No attempt is made to assess the performance of any associated computing systems. Evaluations are usually performed on a gamma camera commercially available within the United Kingdom and recently installed at a clinical site. In consultation with the manufacturer, GCAT selects the site and liaises with local staff to arrange a mutually convenient time for assessment. The manufacturer is encouraged to have a representative present during the evaluation. Three to four days are typically required for the evaluation team to perform the necessary measurements. When access time is limited, the team will modify the protocol to test the camera as thoroughly as possible. Data are acquired on the camera`s computer system and are subsequently transferred to the independent GCAT computer system for analysis. This transfer from site computer to the independent system is effected via a hardware interface and Interfile data transfer. (author).

  4. Dual beam vidicon digitizer

    International Nuclear Information System (INIS)

    Evans, T.L.

    1976-01-01

    A vidicon waveform digitizer which can simultaneously digitize two independent signals has been developed. Either transient or repetitive waveforms can be digitized with this system. A dual beam oscilloscope is used as the signal input device. The light from the oscilloscope traces is optically coupled to a television camera, where the signals are temporarily stored prior to digitizing

  5. A Physical Model-based Correction for Charge Traps in the Hubble Space Telescope ’s Wide Field Camera 3 Near-IR Detector and Its Applications to Transiting Exoplanets and Brown Dwarfs

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yifan; Apai, Dániel; Schneider, Glenn [Department of Astronomy/Steward Observatory, The University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Lew, Ben W. P., E-mail: yzhou@as.arizona.edu [Department of Planetary Science/Lunar and Planetary Laboratory, The University of Arizona, 1640 E. University Boulevard, Tucson, AZ 85718 (United States)

    2017-06-01

    The Hubble Space Telescope Wide Field Camera 3 (WFC3) near-IR channel is extensively used in time-resolved observations, especially for transiting exoplanet spectroscopy as well as brown dwarf and directly imaged exoplanet rotational phase mapping. The ramp effect is the dominant source of systematics in the WFC3 for time-resolved observations, which limits its photometric precision. Current mitigation strategies are based on empirical fits and require additional orbits to help the telescope reach a thermal equilibrium . We show that the ramp-effect profiles can be explained and corrected with high fidelity using charge trapping theories. We also present a model for this process that can be used to predict and to correct charge trap systematics. Our model is based on a very small number of parameters that are intrinsic to the detector. We find that these parameters are very stable between the different data sets, and we provide best-fit values. Our model is tested with more than 120 orbits (∼40 visits) of WFC3 observations and is proved to be able to provide near photon noise limited corrections for observations made with both staring and scanning modes of transiting exoplanets as well as for starting-mode observations of brown dwarfs. After our model correction, the light curve of the first orbit in each visit has the same photometric precision as subsequent orbits, so data from the first orbit no longer need to be discarded. Near-IR arrays with the same physical characteristics (e.g., JWST/NIRCam ) may also benefit from the extension of this model if similar systematic profiles are observed.

  6. In-Flight performance of MESSENGER's Mercury dual imaging system

    Science.gov (United States)

    Hawkins, S.E.; Murchie, S.L.; Becker, K.J.; Selby, C.M.; Turner, F.S.; Noble, M.W.; Chabot, N.L.; Choo, T.H.; Darlington, E.H.; Denevi, B.W.; Domingue, D.L.; Ernst, C.M.; Holsclaw, G.M.; Laslo, N.R.; Mcclintock, W.E.; Prockter, L.M.; Robinson, M.S.; Solomon, S.C.; Sterner, R.E.

    2009-01-01

    The Mercury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, launched in August 2004 and planned for insertion into orbit around Mercury in 2011, has already completed two flybys of the innermost planet. The Mercury Dual Imaging System (MDIS) acquired nearly 2500 images from the first two flybys and viewed portions of Mercury's surface not viewed by Mariner 10 in 1974-1975. Mercury's proximity to the Sun and its slow rotation present challenges to the thermal design for a camera on an orbital mission around Mercury. In addition, strict limitations on spacecraft pointing and the highly elliptical orbit create challenges in attaining coverage at desired geometries and relatively uniform spatial resolution. The instrument designed to meet these challenges consists of dual imagers, a monochrome narrow-angle camera (NAC) with a 1.5?? field of view (FOV) and a multispectral wide-angle camera (WAC) with a 10.5?? FOV, co-aligned on a pivoting platform. The focal-plane electronics of each camera are identical and use a 1024??1024 charge-coupled device detector. The cameras are passively cooled but use diode heat pipes and phase-change-material thermal reservoirs to maintain the thermal configuration during the hot portions of the orbit. Here we present an overview of the instrument design and how the design meets its technical challenges. We also review results from the first two flybys, discuss the quality of MDIS data from the initial periods of data acquisition and how that compares with requirements, and summarize how in-flight tests are being used to improve the quality of the instrument calibration. ?? 2009 SPIE.

  7. Television area detectors

    International Nuclear Information System (INIS)

    Arndt, V.W.

    1977-01-01

    This paper discusses the use of standard television camera tubes as X-ray detectors in X-ray diffraction studies. Standard tubes can be modified to detect X rays by depositing an external X-ray phosphor on the fibre optics face plate either of a highly sensitive television camera tube or of an image intensifier coupled to a camera tube. The author considers various X-ray phosphors and concludes that polycrystalline silver activated ZnS is most suitable for crystallographic applications. In the following sections various types of television camera tubes with adequate light sensitivity for use in an X-ray detection system are described, and also three types of image intensifiers. The digitization of the television output signals and their statistical precision are discussed and the electronic circuitry for the detector system is briefly described. (B.D.)

  8. Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter

    Science.gov (United States)

    Champey, P.; Kobayashi, K.; Winebarger, A.; Cirtain, J.; Hyde, D.; Robertson, B.; Beabout, D.; Beabout, B.; Stewart, M.

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1 percent in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1 percent polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30 percent) quantum efficiency at the Lyman-alpha line. The CLASP cameras were designed to operate with 10 e-/pixel/second dark current, 25 e- read noise, a gain of 2.0 +/- 0.5 and 1.0 percent residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity.

  9. Phase camera experiment for Advanced Virgo

    Energy Technology Data Exchange (ETDEWEB)

    Agatsuma, Kazuhiro, E-mail: agatsuma@nikhef.nl [National Institute for Subatomic Physics, Amsterdam (Netherlands); Beuzekom, Martin van; Schaaf, Laura van der [National Institute for Subatomic Physics, Amsterdam (Netherlands); Brand, Jo van den [National Institute for Subatomic Physics, Amsterdam (Netherlands); VU University, Amsterdam (Netherlands)

    2016-07-11

    We report on a study of the phase camera, which is a frequency selective wave-front sensor of a laser beam. This sensor is utilized for monitoring sidebands produced by phase modulations in a gravitational wave (GW) detector. Regarding the operation of the GW detectors, the laser modulation/demodulation method is used to measure mirror displacements and used for the position controls. This plays a significant role because the quality of controls affect the noise level of the GW detector. The phase camera is able to monitor each sideband separately, which has a great benefit for the manipulation of the delicate controls. Also, overcoming mirror aberrations will be an essential part of Advanced Virgo (AdV), which is a GW detector close to Pisa. Especially low-frequency sidebands can be affected greatly by aberrations in one of the interferometer cavities. The phase cameras allow tracking such changes because the state of the sidebands gives information on mirror aberrations. A prototype of the phase camera has been developed and is currently tested. The performance checks are almost completed and the installation of the optics at the AdV site has started. After the installation and commissioning, the phase camera will be combined to a thermal compensation system that consists of CO{sub 2} lasers and compensation plates. In this paper, we focus on the prototype and show some limitations from the scanner performance. - Highlights: • The phase camera is being developed for a gravitational wave detector. • A scanner performance limits the operation speed and layout design of the system. • An operation range was found by measuring the frequency response of the scanner.

  10. Phase camera experiment for Advanced Virgo

    International Nuclear Information System (INIS)

    Agatsuma, Kazuhiro; Beuzekom, Martin van; Schaaf, Laura van der; Brand, Jo van den

    2016-01-01

    We report on a study of the phase camera, which is a frequency selective wave-front sensor of a laser beam. This sensor is utilized for monitoring sidebands produced by phase modulations in a gravitational wave (GW) detector. Regarding the operation of the GW detectors, the laser modulation/demodulation method is used to measure mirror displacements and used for the position controls. This plays a significant role because the quality of controls affect the noise level of the GW detector. The phase camera is able to monitor each sideband separately, which has a great benefit for the manipulation of the delicate controls. Also, overcoming mirror aberrations will be an essential part of Advanced Virgo (AdV), which is a GW detector close to Pisa. Especially low-frequency sidebands can be affected greatly by aberrations in one of the interferometer cavities. The phase cameras allow tracking such changes because the state of the sidebands gives information on mirror aberrations. A prototype of the phase camera has been developed and is currently tested. The performance checks are almost completed and the installation of the optics at the AdV site has started. After the installation and commissioning, the phase camera will be combined to a thermal compensation system that consists of CO 2 lasers and compensation plates. In this paper, we focus on the prototype and show some limitations from the scanner performance. - Highlights: • The phase camera is being developed for a gravitational wave detector. • A scanner performance limits the operation speed and layout design of the system. • An operation range was found by measuring the frequency response of the scanner.

  11. A novel dual mode neutron-gamma imager

    International Nuclear Information System (INIS)

    Cooper, Robert Lee; Gerling, Mark; Brennan, James S.; Mascarenhas, Nicholas; Mrowka, Stanley; Marleau, Peter

    2010-01-01

    The Neutron Scatter Camera (NSC) can image fission sources and determine their energy spectra at distances of tens of meters and through significant thicknesses of intervening materials in relatively short times (1). We recently completed a 32 element scatter camera and will present recent advances made with this instrument. A novel capability for the scatter camera is dual mode imaging. In normal neutron imaging mode we identify and image neutron events using pulse shape discrimination (PSD) and time of flight in liquid scintillator. Similarly gamma rays are identified from Compton scatter in the front and rear planes for our segmented detector. Rather than reject these events, we show it is possible to construct a gamma-ray image by running the analysis in a 'Compton mode'. Instead of calculating the scattering angle by the kinematics of elastic scatters as is appropriate for neutron events, it can be found by the kinematics of Compton scatters. Our scatter camera has not been optimized as a Compton gamma-ray imager but is found to work reasonably. We studied imaging performance using a Cs137 source. We find that we are able to image the gamma source with reasonable fidelity. We are able to determine gamma energy after some reasonable assumptions. We will detail the various algorithms we have developed for gamma image reconstruction. We will outline areas for improvement, include additional results and compare neutron and gamma mode imaging.

  12. Gamma camera performance: technical assessment protocol

    International Nuclear Information System (INIS)

    Bolster, A.A.; Waddington, W.A.

    1996-01-01

    This protocol addresses the performance assessment of single and dual headed gamma cameras. No attempt is made to assess the performance of any associated computing systems. Evaluations are usually performed on a gamma camera commercially available within the United Kingdom and recently installed at a clinical site. In consultation with the manufacturer, GCAT selects the site and liaises with local staff to arrange a mutually convenient time for assessment. The manufacturer is encouraged to have a representative present during the evaluation. Three to four days are typically required for the evaluation team to perform the necessary measurements. When access time is limited, the team will modify the protocol to test the camera as thoroughly as possible. Data are acquired on the camera's computer system and are subsequently transferred to the independent GCAT computer system for analysis. This transfer from site computer to the independent system is effected via a hardware interface and Interfile data transfer. (author)

  13. The development of large-aperture test system of infrared camera and visible CCD camera

    Science.gov (United States)

    Li, Yingwen; Geng, Anbing; Wang, Bo; Wang, Haitao; Wu, Yanying

    2015-10-01

    Infrared camera and CCD camera dual-band imaging system is used in many equipment and application widely. If it is tested using the traditional infrared camera test system and visible CCD test system, 2 times of installation and alignment are needed in the test procedure. The large-aperture test system of infrared camera and visible CCD camera uses the common large-aperture reflection collimator, target wheel, frame-grabber, computer which reduces the cost and the time of installation and alignment. Multiple-frame averaging algorithm is used to reduce the influence of random noise. Athermal optical design is adopted to reduce the change of focal length location change of collimator when the environmental temperature is changing, and the image quality of the collimator of large field of view and test accuracy are also improved. Its performance is the same as that of the exotic congener and is much cheaper. It will have a good market.

  14. The Legal Implications of Surveillance Cameras

    Science.gov (United States)

    Steketee, Amy M.

    2012-01-01

    The nature of school security has changed dramatically over the last decade. Schools employ various measures, from metal detectors to identification badges to drug testing, to promote the safety and security of staff and students. One of the increasingly prevalent measures is the use of security cameras. In fact, the U.S. Department of Education…

  15. LSST camera readout chip ASPIC: test tools

    International Nuclear Information System (INIS)

    Antilogus, P; Bailly, Ph; Juramy, C; Lebbolo, H; Martin, D; Jeglot, J; Moniez, M; Tocut, V; Wicek, F

    2012-01-01

    The LSST camera will have more than 3000 video-processing channels. The readout of this large focal plane requires a very compact readout chain. The correlated ''Double Sampling technique'', which is generally used for the signal readout of CCDs, is also adopted for this application and implemented with the so called ''Dual Slope integrator'' method. We have designed and implemented an ASIC for LSST: the Analog Signal Processing asIC (ASPIC). The goal is to amplify the signal close to the output, in order to maximize signal to noise ratio, and to send differential outputs to the digitization. Others requirements are that each chip should process the output of half a CCD, that is 8 channels and should operate at 173 K. A specific Back End board has been designed especially for lab test purposes. It manages the clock signals, digitizes the analog differentials outputs of ASPIC and stores data into a memory. It contains 8 ADCs (18 bits), 512 kwords memory and an USB interface. An FPGA manages all signals from/to all components on board and generates the timing sequence for ASPIC. Its firmware is written in Verilog and VHDL languages. Internals registers permit to define various tests parameters of the ASPIC. A Labview GUI allows to load or update these registers and to check a proper operation. Several series of tests, including linearity, noise and crosstalk, have been performed over the past year to characterize the ASPIC at room and cold temperature. At present, the ASPIC, Back-End board and CCD detectors are being integrated to perform a characterization of the whole readout chain.

  16. LSST camera readout chip ASPIC: test tools

    Science.gov (United States)

    Antilogus, P.; Bailly, Ph; Jeglot, J.; Juramy, C.; Lebbolo, H.; Martin, D.; Moniez, M.; Tocut, V.; Wicek, F.

    2012-02-01

    The LSST camera will have more than 3000 video-processing channels. The readout of this large focal plane requires a very compact readout chain. The correlated ''Double Sampling technique'', which is generally used for the signal readout of CCDs, is also adopted for this application and implemented with the so called ''Dual Slope integrator'' method. We have designed and implemented an ASIC for LSST: the Analog Signal Processing asIC (ASPIC). The goal is to amplify the signal close to the output, in order to maximize signal to noise ratio, and to send differential outputs to the digitization. Others requirements are that each chip should process the output of half a CCD, that is 8 channels and should operate at 173 K. A specific Back End board has been designed especially for lab test purposes. It manages the clock signals, digitizes the analog differentials outputs of ASPIC and stores data into a memory. It contains 8 ADCs (18 bits), 512 kwords memory and an USB interface. An FPGA manages all signals from/to all components on board and generates the timing sequence for ASPIC. Its firmware is written in Verilog and VHDL languages. Internals registers permit to define various tests parameters of the ASPIC. A Labview GUI allows to load or update these registers and to check a proper operation. Several series of tests, including linearity, noise and crosstalk, have been performed over the past year to characterize the ASPIC at room and cold temperature. At present, the ASPIC, Back-End board and CCD detectors are being integrated to perform a characterization of the whole readout chain.

  17. Dual ionization chamber

    International Nuclear Information System (INIS)

    Mallory, J.; Turlej, Z.

    1981-01-01

    Dual ionization chambers are provided for use with an electronic smoke detector. The chambers are separated by electrically-conductive partition. A single radiation source extends through the partition into both chambers, ionizing the air in each. The mid-point current of the device may be balanced by adjusting the position of the source

  18. Making Ceramic Cameras

    Science.gov (United States)

    Squibb, Matt

    2009-01-01

    This article describes how to make a clay camera. This idea of creating functional cameras from clay allows students to experience ceramics, photography, and painting all in one unit. (Contains 1 resource and 3 online resources.)

  19. A flexible geometry Compton camera for industrial gamma ray imaging

    International Nuclear Information System (INIS)

    Royle, G.J.; Speller, R.D.

    1996-01-01

    A design for a Compton scatter camera is proposed which is applicable to gamma ray imaging within limited access industrial sites. The camera consists of a number of single element detectors arranged in a small cluster. Coincidence circuitry enables the detectors to act as a scatter camera. Positioning the detector cluster at various locations within the site, and subsequent reconstruction of the recorded data, allows an image to be obtained. The camera design allows flexibility to cater for limited space or access simply by positioning the detectors in the optimum geometric arrangement within the space allowed. The quality of the image will be limited but imaging could still be achieved in regions which are otherwise inaccessible. Computer simulation algorithms have been written to optimize the various parameters involved, such as geometrical arrangement of the detector cluster and the positioning of the cluster within the site, and to estimate the performance of such a device. Both scintillator and semiconductor detectors have been studied. A prototype camera has been constructed which operates three small single element detectors in coincidence. It has been tested in a laboratory simulation of an industrial site. This consisted of a small room (2 m wide x 1 m deep x 2 m high) into which the only access points were two 6 cm diameter holes in a side wall. Simple images of Cs-137 sources have been produced. The work described has been done on behalf of BNFL for applications at their Sellafield reprocessing plant in the UK

  20. Adapting Virtual Camera Behaviour

    DEFF Research Database (Denmark)

    Burelli, Paolo

    2013-01-01

    In a three-dimensional virtual environment aspects such as narrative and interaction completely depend on the camera since the camera defines the player’s point of view. Most research works in automatic camera control aim to take the control of this aspect from the player to automatically gen- er...

  1. Choosing a Motion Detector.

    Science.gov (United States)

    Ballard, David M.

    1990-01-01

    Examines the characteristics of three types of motion detectors: Doppler radar, infrared, and ultrasonic wave, and how they are used on school buses to prevent students from being killed by their own school bus. Other safety devices cited are bus crossing arms and a camera monitor system. (MLF)

  2. Lepton detector workshop summary

    International Nuclear Information System (INIS)

    Imlay, R.; Iwata, S.; Thorndike, A.

    1976-01-01

    The study group met from June 7 to 11, 1976, with the dual purpose of reviewing an earlier Lepton Detector report in order to resolve some of the remaining design problems and of considering possible alternatives. Since the role of this group was primarily that of providing a critique of the earlier work, the reader is referred to that earlier paper for the general motivation and design of the detector. Problems studied at this session are described

  3. Bullet Design and Fabrication of Dual Mode Pyroelectric Sensor: High Sensitive Energymeter for Nd: YAG Laser and Detector for Chopped He-Ne Laser

    Directory of Open Access Journals (Sweden)

    S. SATAPATHY

    2008-05-01

    Full Text Available Pyroelectric sensor using TGS has been designed and fabricated which can be operated in laser energy meter mode as well as pyroelectric detector mode. The amplifying circuit configuration has very good signal to noise ratio, very high input impedance and low drift. The pyroelectric sensor has been tested using Q-switched Nd: YAG laser and chopped He-Ne laser. The sensitivity of pyroelectric sensor in energymeter mode is 421.7V/J and the voltage responsivity of the pyroelectric sensor is 3.27 V/W in detector mode.

  4. Application of phase matching autofocus in airborne long-range oblique photography camera

    Science.gov (United States)

    Petrushevsky, Vladimir; Guberman, Asaf

    2014-06-01

    The Condor2 long-range oblique photography (LOROP) camera is mounted in an aerodynamically shaped pod carried by a fast jet aircraft. Large aperture, dual-band (EO/MWIR) camera is equipped with TDI focal plane arrays and provides high-resolution imagery of extended areas at long stand-off ranges, at day and night. Front Ritchey-Chretien optics is made of highly stable materials. However, the camera temperature varies considerably in flight conditions. Moreover, a composite-material structure of the reflective objective undergoes gradual dehumidification in dry nitrogen atmosphere inside the pod, causing some small decrease of the structure length. The temperature and humidity effects change a distance between the mirrors by just a few microns. The distance change is small but nevertheless it alters the camera's infinity focus setpoint significantly, especially in the EO band. To realize the optics' resolution potential, the optimal focus shall be constantly maintained. In-flight best focus calibration and temperature-based open-loop focus control give mostly satisfactory performance. To get even better focusing precision, a closed-loop phase-matching autofocus method was developed for the camera. The method makes use of an existing beamsharer prism FPA arrangement where aperture partition exists inherently in an area of overlap between the adjacent detectors. The defocus is proportional to an image phase shift in the area of overlap. Low-pass filtering of raw defocus estimate reduces random errors related to variable scene content. Closed-loop control converges robustly to precise focus position. The algorithm uses the temperature- and range-based focus prediction as an initial guess for the closed-loop phase-matching control. The autofocus algorithm achieves excellent results and works robustly in various conditions of scene illumination and contrast.

  5. The MVACS Robotic Arm Camera

    Science.gov (United States)

    Keller, H. U.; Hartwig, H.; Kramm, R.; Koschny, D.; Markiewicz, W. J.; Thomas, N.; Fernades, M.; Smith, P. H.; Reynolds, R.; Lemmon, M. T.; Weinberg, J.; Marcialis, R.; Tanner, R.; Boss, B. J.; Oquest, C.; Paige, D. A.

    2001-08-01

    The Robotic Arm Camera (RAC) is one of the key instruments newly developed for the Mars Volatiles and Climate Surveyor payload of the Mars Polar Lander. This lightweight instrument employs a front lens with variable focus range and takes images at distances from 11 mm (image scale 1:1) to infinity. Color images with a resolution of better than 50 μm can be obtained to characterize the Martian soil. Spectral information of nearby objects is retrieved through illumination with blue, green, and red lamp sets. The design and performance of the camera are described in relation to the science objectives and operation. The RAC uses the same CCD detector array as the Surface Stereo Imager and shares the readout electronics with this camera. The RAC is mounted at the wrist of the Robotic Arm and can characterize the contents of the scoop, the samples of soil fed to the Thermal Evolved Gas Analyzer, the Martian surface in the vicinity of the lander, and the interior of trenches dug out by the Robotic Arm. It can also be used to take panoramic images and to retrieve stereo information with an effective baseline surpassing that of the Surface Stereo Imager by about a factor of 3.

  6. Advanced system for Gamma Cameras modernization

    International Nuclear Information System (INIS)

    Osorio Deliz, J. F.; Diaz Garcia, A.; Arista Romeu, E. J.

    2015-01-01

    Analog and digital gamma cameras still largely used in developing countries. Many of them rely in old hardware electronics, which in many cases limits their use in actual nuclear medicine diagnostic studies. Consequently, there are different worldwide companies that produce medical equipment engaged into a partial or total Gamma Cameras modernization. Present work has demonstrated the possibility of substitution of almost entire signal processing electronics placed at inside a Gamma Camera detector head by a digitizer PCI card. this card includes four 12 Bits Analog-to-Digital-Converters of 50 MHz speed. It has been installed in a PC and controlled through software developed in Lab View. Besides, there were done some changes to the hardware inside the detector head including redesign of the Orientation Display Block (ODA card). Also a new electronic design was added to the Microprocessor Control Block (MPA card) which comprised a PIC micro controller acting as a tuning system for individual Photomultiplier Tubes. The images, obtained by measurement of 99m Tc point radioactive source, using modernized camera head demonstrate its overall performance. The system was developed and tested in an old Gamma Camera ORBITER II SIEMENS GAMMASONIC at National Institute of Oncology and Radiobiology (INOR) under CAMELUD project supported by National Program PNOULU and IAEA . (Author)

  7. Nonmedical applications of a positron camera

    International Nuclear Information System (INIS)

    Hawkesworth, M.R.; Parker, D.J.; Fowles, P.; Crilly, J.F.; Jefferies, N.L.; Jonkers, G.

    1991-01-01

    The positron camera in the School on Physics and Space Research, University of Birmingham, is based on position-sensitive multiwire γ-ray detectors developed at the Rutherford Appleton Laboratory. The current characteristics of the camera are discussed with particular reference to its suitability for flow mapping in industrial subjects. The techniques developed for studying the dynamics of processes with time scales ranging from milliseconds to days are described, and examples of recent results from a variety of industrial applications are presented. (orig.)

  8. Effect of automated tube voltage selection, integrated circuit detector and advanced iterative reconstruction on radiation dose and image quality of 3rd generation dual-source aortic CT angiography: An intra-individual comparison.

    Science.gov (United States)

    Mangold, Stefanie; De Cecco, Carlo N; Wichmann, Julian L; Canstein, Christian; Varga-Szemes, Akos; Caruso, Damiano; Fuller, Stephen R; Bamberg, Fabian; Nikolaou, Konstantin; Schoepf, U Joseph

    2016-05-01

    To compare, on an intra-individual basis, the effect of automated tube voltage selection (ATVS), integrated circuit detector and advanced iterative reconstruction on radiation dose and image quality of aortic CTA studies using 2nd and 3rd generation dual-source CT (DSCT). We retrospectively evaluated 32 patients who had undergone CTA of the entire aorta with both 2nd generation DSCT at 120kV using filtered back projection (FBP) (protocol 1) and 3rd generation DSCT using ATVS, an integrated circuit detector and advanced iterative reconstruction (protocol 2). Contrast-to-noise ratio (CNR) was calculated. Image quality was subjectively evaluated using a five-point scale. Radiation dose parameters were recorded. All studies were considered of diagnostic image quality. CNR was significantly higher with protocol 2 (15.0±5.2 vs 11.0±4.2; p<.0001). Subjective image quality analysis revealed no significant differences for evaluation of attenuation (p=0.08501) but image noise was rated significantly lower with protocol 2 (p=0.0005). Mean tube voltage and effective dose were 94.7±14.1kV and 6.7±3.9mSv with protocol 2; 120±0kV and 11.5±5.2mSv with protocol 1 (p<0.0001, respectively). Aortic CTA performed with 3rd generation DSCT, ATVS, integrated circuit detector, and advanced iterative reconstruction allow a substantial reduction of radiation exposure while improving image quality in comparison to 120kV imaging with FBP. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. SPECT and 123I-Iodolisuride (123-I-ILIS) in extra-pyramidal syndromes. The use of different models of γ-cameras

    International Nuclear Information System (INIS)

    Ribeiro, M.J.; Jannuario, C.; Santos, A.C.; Cunha, L.; Pedroso de Lima, J.J.; Prunier-Levilion, C.; Autret, A.; Guilloteau, D.; Besnard, J.C.; Baulieu, J.L.; Chassat, F.; Bekhechi, D.; Marchand, J.; Mauclaire, L.; Catela, L.

    1999-01-01

    The aim of this work was to evaluate 123 I-ILIS as a radioligand of dopamine receptors in patients with extra-pyramidal diseases by using different cameras in two different centers. 45 patients were included and divided in 2 groups: group I (n=28): idiopathic Parkinson disease, group II (n=17): other extra-pyramidal syndrome. 123 I-ILIS, 1.7 to 2.8 MBq/kg, was injected after informed consent. Imaging was performed with a single head camera, a dual head camera, a triple head camera and a brain dedicated annular detector. The pattern of the transverse slices containing the basal ganglia was classified according to 3 types: type 1: visible basal ganglia and invisible cortex, type 2: invisible basal ganglia and visible cortex, type 3: visible basal ganglia and cortex. Striatal/frontal cortex ratio (S/FC) was calculated from standardized, geometrical ROI's. No patient showed any undesirable effect. All SPECT images were interpretable. In group 1, 45/45 scintigraphic pattern were type 1 or 3, in group II 18/23 scintigraphic patterns were type 2 or 3. S/FC was significantly lower in group II than in group I patients. We conclude that 123 I-ILIS SPECT can be performed with any conventional γ-camera. It provides functional informations about the striatal dopaminergic synapse in patients with extra-pyramidal degenerative disease, and could be useful in the differential diagnosis between Parkinson disease and other extra-pyramidal syndromes. (author)

  10. Radiation camera exposure control

    International Nuclear Information System (INIS)

    Martone, R.J.; Yarsawich, M.; Wolczek, W.

    1976-01-01

    A system and method for governing the exposure of an image generated by a radiation camera to an image sensing camera is disclosed. The exposure is terminated in response to the accumulation of a predetermined quantity of radiation, defining a radiation density, occurring in a predetermined area. An index is produced which represents the value of that quantity of radiation whose accumulation causes the exposure termination. The value of the predetermined radiation quantity represented by the index is sensed so that the radiation camera image intensity can be calibrated to compensate for changes in exposure amounts due to desired variations in radiation density of the exposure, to maintain the detectability of the image by the image sensing camera notwithstanding such variations. Provision is also made for calibrating the image intensity in accordance with the sensitivity of the image sensing camera, and for locating the index for maintaining its detectability and causing the proper centering of the radiation camera image

  11. GRACE star camera noise

    Science.gov (United States)

    Harvey, Nate

    2016-08-01

    Extending results from previous work by Bandikova et al. (2012) and Inacio et al. (2015), this paper analyzes Gravity Recovery and Climate Experiment (GRACE) star camera attitude measurement noise by processing inter-camera quaternions from 2003 to 2015. We describe a correction to star camera data, which will eliminate a several-arcsec twice-per-rev error with daily modulation, currently visible in the auto-covariance function of the inter-camera quaternion, from future GRACE Level-1B product releases. We also present evidence supporting the argument that thermal conditions/settings affect long-term inter-camera attitude biases by at least tens-of-arcsecs, and that several-to-tens-of-arcsecs per-rev star camera errors depend largely on field-of-view.

  12. Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    Science.gov (United States)

    Champey, Patrick; Kobayashi, Ken; Winebarger, Amy; Cirtin, Jonathan; Hyde, David; Robertson, Bryan; Beabout, Brent; Beabout, Dyana; Stewart, Mike

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1% in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1% polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30%) quantum efficiency at the Lyman-$\\alpha$ line. The CLASP cameras were designed to operate with =10 e- /pixel/second dark current, = 25 e- read noise, a gain of 2.0 and =0.1% residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity.

  13. Solid state video cameras

    CERN Document Server

    Cristol, Y

    2013-01-01

    Solid State Video Cameras reviews the state of the art in the field of solid-state television cameras as compiled from patent literature. Organized into 10 chapters, the book begins with the basic array types of solid-state imagers and appropriate read-out circuits and methods. Documents relating to improvement of picture quality, such as spurious signal suppression, uniformity correction, or resolution enhancement, are also cited. The last part considerssolid-state color cameras.

  14. Radiation detectors

    International Nuclear Information System (INIS)

    2013-01-01

    This sixth chapter presents the operational principles of the radiation detectors; detection using photographic emulsions; thermoluminescent detectors; gas detectors; scintillation detectors; liquid scintillation detectors; detectors using semiconductor materials; calibration of detectors; Bragg-Gray theory; measurement chain and uncertainties associated to measurements

  15. Characterization of a PET Camera Optimized for Prostate Imaging

    International Nuclear Information System (INIS)

    Huber, Jennifer S.; Choong, Woon-Seng; Moses, William W.; Qi, Jinyi; Hu, Jicun; Wang, G.C.; Wilson, David; Oh, Sang; Huesman, RonaldH.; Derenzo, Stephen E.

    2005-01-01

    We present the characterization of a positron emission tomograph for prostate imaging that centers a patient between a pair of external curved detector banks (ellipse: 45 cm minor, 70 cm major axis). The distance between detector banks adjusts to allow patient access and to position the detectors as closely as possible for maximum sensitivity with patients of various sizes. Each bank is composed of two axial rows of 20 HR+ block detectors for a total of 80 detectors in the camera. The individual detectors are angled in the transaxial plane to point towards the prostate to reduce resolution degradation in that region. The detectors are read out by modified HRRT data acquisition electronics. Compared to a standard whole-body PET camera, our dedicated-prostate camera has the same sensitivity and resolution, less background (less randoms and lower scatter fraction) and a lower cost. We have completed construction of the camera. Characterization data and reconstructed images of several phantoms are shown. Sensitivity of a point source in the center is 946 cps/mu Ci. Spatial resolution is 4 mm FWHM in the central region

  16. Evaluation of the optical cross talk level in the SiPMs adopted in ASTRI SST-2M Cherenkov Camera using EASIROC front-end electronics

    International Nuclear Information System (INIS)

    Impiombato, D; Giarrusso, S; Mineo, T; Agnetta, G; Biondo, B; Catalano, O; Gargano, C; Rosa, G La; Russo, F; Sottile, G; Belluso, M; Billotta, S; Bonanno, G; Garozzo, S; Marano, D; Romeo, G

    2014-01-01

    ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana), is a flagship project of the Italian Ministry of Education, University and Research whose main goal is the design and construction of an end-to-end prototype of the Small Size of Telescopes of the Cherenkov Telescope Array. The prototype, named ASTRI SST-2M, will adopt a wide field dual mirror optical system in a Schwarzschild-Couder configuration to explore the VHE range of the electromagnetic spectrum. The camera at the focal plane is based on Silicon Photo-Multipliers detectors which is an innovative solution for the detection astronomical Cherenkov light. This contribution reports some preliminary results on the evaluation of the optical cross talk level among the SiPM pixels foreseen for the ASTRI SST-2M camera

  17. Collimated trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    1980-01-01

    The objects of this invention are first to reduce the time required to obtain statistically significant data in trans-axial tomographic radioisotope scanning using a scintillation camera. Secondly, to provide a scintillation camera system to increase the rate of acceptance of radioactive events to contribute to the positional information obtainable from a known radiation source without sacrificing spatial resolution. Thirdly to reduce the scanning time without loss of image clarity. The system described comprises a scintillation camera detector, means for moving this in orbit about a cranial-caudal axis relative to a patient and a collimator having septa defining apertures such that gamma rays perpendicular to the axis are admitted with high spatial resolution, parallel to the axis with low resolution. The septa may be made of strips of lead. Detailed descriptions are given. (U.K.)

  18. Gate Simulation of a Gamma Camera

    International Nuclear Information System (INIS)

    Abidi, Sana; Mlaouhi, Zohra

    2008-01-01

    Medical imaging is a very important diagnostic because it allows for an exploration of the internal human body. The nuclear imaging is an imaging technique used in the nuclear medicine. It is to determine the distribution in the body of a radiotracers by detecting the radiation it emits using a detection device. Two methods are commonly used: Single Photon Emission Computed Tomography (SPECT) and the Positrons Emission Tomography (PET). In this work we are interested on modelling of a gamma camera. This simulation is based on Monte-Carlo language and in particular Gate simulator (Geant4 Application Tomographic Emission). We have simulated a clinical gamma camera called GAEDE (GKS-1) and then we validate these simulations by experiments. The purpose of this work is to monitor the performance of these gamma camera and the optimization of the detector performance and the the improvement of the images quality. (Author)

  19. Cameras in mobile phones

    Science.gov (United States)

    Nummela, Ville; Viinikanoja, Jarkko; Alakarhu, Juha

    2006-04-01

    One of the fastest growing markets in consumer markets today are camera phones. During past few years total volume has been growing fast and today millions of mobile phones with camera will be sold. At the same time resolution and functionality of the cameras has been growing from CIF towards DSC level. From camera point of view the mobile world is an extremely challenging field. Cameras should have good image quality but in small size. They also need to be reliable and their construction should be suitable for mass manufacturing. All components of the imaging chain should be well optimized in this environment. Image quality and usability are the most important parameters to user. The current trend of adding more megapixels to cameras and at the same time using smaller pixels is affecting both. On the other hand reliability and miniaturization are key drivers for product development as well as the cost. In optimized solution all parameters are in balance but the process of finding the right trade-offs is not an easy task. In this paper trade-offs related to optics and their effects to image quality and usability of cameras are discussed. Key development areas from mobile phone camera point of view are also listed.

  20. Thermal Cameras and Applications

    DEFF Research Database (Denmark)

    Gade, Rikke; Moeslund, Thomas B.

    2014-01-01

    Thermal cameras are passive sensors that capture the infrared radiation emitted by all objects with a temperature above absolute zero. This type of camera was originally developed as a surveillance and night vision tool for the military, but recently the price has dropped, significantly opening up...... a broader field of applications. Deploying this type of sensor in vision systems eliminates the illumination problems of normal greyscale and RGB cameras. This survey provides an overview of the current applications of thermal cameras. Applications include animals, agriculture, buildings, gas detection......, industrial, and military applications, as well as detection, tracking, and recognition of humans. Moreover, this survey describes the nature of thermal radiation and the technology of thermal cameras....

  1. Gamma cameras - a method of evaluation

    International Nuclear Information System (INIS)

    Oates, L.; Bibbo, G.

    2000-01-01

    Full text: With the sophistication and longevity of the modern gamma camera it is not often that the need arises to evaluate a gamma camera for purchase. We have recently been placed in the position of retiring our two single headed cameras of some vintage and replacing them with a state of the art dual head variable angle gamma camera. The process used for the evaluation consisted of five parts: (1) Evaluation of the technical specification as expressed in the tender document; (2) A questionnaire adapted from the British Society of Nuclear Medicine; (3) Site visits to assess gantry configuration, movement, patient access and occupational health, welfare and safety considerations; (4) Evaluation of the processing systems offered; (5) Whole of life costing based on equally configured systems. The results of each part of the evaluation were expressed using a weighted matrix analysis with each of the criteria assessed being weighted in accordance with their importance to the provision of an effective nuclear medicine service for our centre and the particular importance to paediatric nuclear medicine. This analysis provided an objective assessment of each gamma camera system from which a purchase recommendation was made. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  2. History of infrared detectors

    Science.gov (United States)

    Rogalski, A.

    2012-09-01

    This paper overviews the history of infrared detector materials starting with Herschel's experiment with thermometer on February 11th, 1800. Infrared detectors are in general used to detect, image, and measure patterns of the thermal heat radiation which all objects emit. At the beginning, their development was connected with thermal detectors, such as thermocouples and bolometers, which are still used today and which are generally sensitive to all infrared wavelengths and operate at room temperature. The second kind of detectors, called the photon detectors, was mainly developed during the 20th Century to improve sensitivity and response time. These detectors have been extensively developed since the 1940's. Lead sulphide (PbS) was the first practical IR detector with sensitivity to infrared wavelengths up to ˜3 μm. After World War II infrared detector technology development was and continues to be primarily driven by military applications. Discovery of variable band gap HgCdTe ternary alloy by Lawson and co-workers in 1959 opened a new area in IR detector technology and has provided an unprecedented degree of freedom in infrared detector design. Many of these advances were transferred to IR astronomy from Departments of Defence research. Later on civilian applications of infrared technology are frequently called "dual-use technology applications." One should point out the growing utilisation of IR technologies in the civilian sphere based on the use of new materials and technologies, as well as the noticeable price decrease in these high cost technologies. In the last four decades different types of detectors are combined with electronic readouts to make detector focal plane arrays (FPAs). Development in FPA technology has revolutionized infrared imaging. Progress in integrated circuit design and fabrication techniques has resulted in continued rapid growth in the size and performance of these solid state arrays.

  3. Unmanned Ground Vehicle Perception Using Thermal Infrared Cameras

    Science.gov (United States)

    Rankin, Arturo; Huertas, Andres; Matthies, Larry; Bajracharya, Max; Assad, Christopher; Brennan, Shane; Bellut, Paolo; Sherwin, Gary

    2011-01-01

    TIR cameras can be used for day/night Unmanned Ground Vehicle (UGV) autonomous navigation when stealth is required. The quality of uncooled TIR cameras has significantly improved over the last decade, making them a viable option at low speed Limiting factors for stereo ranging with uncooled LWIR cameras are image blur and low texture scenes TIR perception capabilities JPL has explored includes: (1) single and dual band TIR terrain classification (2) obstacle detection (pedestrian, vehicle, tree trunks, ditches, and water) (3) perception thru obscurants

  4. The test of intrinsic uniformity is one of the basic tests to check the status of the detectors of gamma cameras, and as such is contained in RD 1 841/1997 Quality Control in Nuclear Medicine

    International Nuclear Information System (INIS)

    Gonzalez Soto, X. L.; Gonzalez Ruiz, C.; Lopez-Boto, M. A.; Polo Cezon, R.

    2015-01-01

    Spanish Protocol Quality Control Instrumentation in Nuclear Medicine provides guidelines for conducting this test, similar to those established in the NEMA protocol NEMA Protocol for the calculation of the uniformity intrinsic in GAMMA cameras: application and comparison with the SQFTWARE of the manufacturer. it is advisable to conduct a study to ensure that the results for the test of intrinsic uniformity of the software provided by the equipment manufacturer are equivalent to those obtained by applying the protocol recommended by the SEFM before using this software for performing quality control. (Author)

  5. Prism-based single-camera system for stereo display

    Science.gov (United States)

    Zhao, Yue; Cui, Xiaoyu; Wang, Zhiguo; Chen, Hongsheng; Fan, Heyu; Wu, Teresa

    2016-06-01

    This paper combines the prism and single camera and puts forward a method of stereo imaging with low cost. First of all, according to the principle of geometrical optics, we can deduce the relationship between the prism single-camera system and dual-camera system, and according to the principle of binocular vision we can deduce the relationship between binoculars and dual camera. Thus we can establish the relationship between the prism single-camera system and binoculars and get the positional relation of prism, camera, and object with the best effect of stereo display. Finally, using the active shutter stereo glasses of NVIDIA Company, we can realize the three-dimensional (3-D) display of the object. The experimental results show that the proposed approach can make use of the prism single-camera system to simulate the various observation manners of eyes. The stereo imaging system, which is designed by the method proposed by this paper, can restore the 3-D shape of the object being photographed factually.

  6. ePix100 camera: Use and applications at LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Carini, G. A., E-mail: carini@slac.stanford.edu; Alonso-Mori, R.; Blaj, G.; Caragiulo, P.; Chollet, M.; Damiani, D.; Dragone, A.; Feng, Y.; Haller, G.; Hart, P.; Hasi, J.; Herbst, R.; Herrmann, S.; Kenney, C.; Lemke, H.; Manger, L.; Markovic, B.; Mehta, A.; Nelson, S.; Nishimura, K. [SLAC National Accelerator Laboratory (United States); and others

    2016-07-27

    The ePix100 x-ray camera is a new system designed and built at SLAC for experiments at the Linac Coherent Light Source (LCLS). The camera is the first member of a family of detectors built around a single hardware and software platform, supporting a variety of front-end chips. With a readout speed of 120 Hz, matching the LCLS repetition rate, a noise lower than 80 e-rms and pixels of 50 µm × 50 µm, this camera offers a viable alternative to fast readout, direct conversion, scientific CCDs in imaging mode. The detector, designed for applications such as X-ray Photon Correlation Spectroscopy (XPCS) and wavelength dispersive X-ray Emission Spectroscopy (XES) in the energy range from 2 to 10 keV and above, comprises up to 0.5 Mpixels in a very compact form factor. In this paper, we report the performance of the camera during its first use at LCLS.

  7. Virtual Monoenergetic Images From a Novel Dual-Layer Spectral Detector Computed Tomography Scanner in Portal Venous Phase: Adjusted Window Settings Depending on Assessment Focus Are Essential for Image Interpretation.

    Science.gov (United States)

    Hickethier, Tilman; Iuga, Andra-Iza; Lennartz, Simon; Hauger, Myriam; Byrtus, Jonathan; Luetkens, Julian A; Haneder, Stefan; Maintz, David; Doerner, Jonas

    We aimed to determine optimal window settings for conventional polyenergetic (PolyE) and virtual monoenergetic images (MonoE) derived from abdominal portal venous phase computed tomography (CT) examinations on a novel dual-layer spectral-detector CT (SDCT). From 50 patients, SDCT data sets MonoE at 40 kiloelectron volt as well as PolyE were reconstructed and best individual window width and level values manually were assessed separately for evaluation of abdominal arteries as well as for liver lesions. Via regression analysis, optimized individual values were mathematically calculated. Subjective image quality parameters, vessel, and liver lesion diameters were measured to determine influences of different W/L settings. Attenuation and contrast-to-noise values were significantly higher in MonoE compared with PolyE. Compared with standard settings, almost all adjusted W/L settings varied significantly and yielded higher subjective scoring. No differences were found between manually adjusted and mathematically calculated W/L settings. PolyE and MonoE from abdominal portal venous phase SDCT examinations require appropriate W/L settings depending on reconstruction technique and assessment focus.

  8. ARNICA, the Arcetri near-infrared camera: Astronomical performance assessment.

    Science.gov (United States)

    Hunt, L. K.; Lisi, F.; Testi, L.; Baffa, C.; Borelli, S.; Maiolino, R.; Moriondo, G.; Stanga, R. M.

    1996-01-01

    The Arcetri near-infrared camera ARNICA was built as a users' instrument for the Infrared Telescope at Gornergrat (TIRGO), and is based on a 256x256 NICMOS 3 detector. In this paper, we discuss ARNICA's optical and astronomical performance at the TIRGO and at the William Herschel Telescope on La Palma. Optical performance is evaluated in terms of plate scale, distortion, point spread function, and ghosting. Astronomical performance is characterized by camera efficiency, sensitivity, and spatial uniformity of the photometry.

  9. Bin mode estimation methods for Compton camera imaging

    International Nuclear Information System (INIS)

    Ikeda, S.; Odaka, H.; Uemura, M.; Takahashi, T.; Watanabe, S.; Takeda, S.

    2014-01-01

    We study the image reconstruction problem of a Compton camera which consists of semiconductor detectors. The image reconstruction is formulated as a statistical estimation problem. We employ a bin-mode estimation (BME) and extend an existing framework to a Compton camera with multiple scatterers and absorbers. Two estimation algorithms are proposed: an accelerated EM algorithm for the maximum likelihood estimation (MLE) and a modified EM algorithm for the maximum a posteriori (MAP) estimation. Numerical simulations demonstrate the potential of the proposed methods

  10. Advanced CCD camera developments

    Energy Technology Data Exchange (ETDEWEB)

    Condor, A. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    Two charge coupled device (CCD) camera systems are introduced and discussed, describing briefly the hardware involved, and the data obtained in their various applications. The Advanced Development Group Defense Sciences Engineering Division has been actively designing, manufacturing, fielding state-of-the-art CCD camera systems for over a decade. These systems were originally developed for the nuclear test program to record data from underground nuclear tests. Today, new and interesting application for these systems have surfaced and development is continuing in the area of advanced CCD camera systems, with the new CCD camera that will allow experimenters to replace film for x-ray imaging at the JANUS, USP, and NOVA laser facilities.

  11. Speckle imaging with the PAPA detector. [Precision Analog Photon Address

    Science.gov (United States)

    Papaliolios, C.; Nisenson, P.; Ebstein, S.

    1985-01-01

    A new 2-D photon-counting camera, the PAPA (precision analog photon address) detector has been built, tested, and used successfully for the acquisition of speckle imaging data. The camera has 512 x 512 pixels and operates at count rates of at least 200,000/sec. In this paper, technical details on the camera are presented and some of the laboratory and astronomical results are included which demonstrate the detector's capabilities.

  12. Ionization detector

    International Nuclear Information System (INIS)

    Steele, D.S.

    1987-01-01

    An ionization detector having an array of detectors has, for example, grounding pads positioned in the spaces between some detectors (data detectors) and other detectors (reference detectors). The grounding pads are kept at zero electric potential, i.e. grounded. The grounding serves to drain away electrons and thereby prevent an unwanted accumulation of charge in the spaces, and cause the electric field lines to be more perpendicular to the detectors in regions near the grounding pads. Alternatively, no empty space is provided there being additional, grounded, detectors provided between the data and reference detectors. (author)

  13. Coronary dual source multi detector computed tomography in patients suspected of coronary artery disease: Prevalence of incidental extra-cardiac findings

    International Nuclear Information System (INIS)

    Bendix, K.; Jensen, J.M.; Poulsen, S.; Mygind, N.; Norgaard, B.L.

    2011-01-01

    Objectives: (1) To establish the prevalence of incidental extra-cardiac findings (ECFs) in coronary multi detector computed tomography (CCT) performed in a large, homogeneous cohort of patients suspected of coronary artery disease (CAD). (2) To examine whether any association can be established between ECFs and pretest risk as determined by conventional risk factors for CAD, the Diamond-Forrester risk model or coronary artery calcium scores. (3) To assess cost related to extra-cardiac examinations. Design: Retrospective study of consecutive patients who had CCT performed. A large field of view was recreated from the non-enhanced CT scan and evaluated by a radiologist for incidental ECFs. Subjects: Patients with chest pain referred to CTA by a cardiologist. Results: In 1383 patients a total of 481 ECFs were indentified, 378 minor (meaning no follow-up was needed) and 103 major ECFs (ECF followed up clinically and/or with additional imaging), in a total of 393 (28%) patients. 85 (6%) patients had one major ECF and 9 (0.7%) patients had two major ECFs. In 19 (4 cases of malignancy) patients the major ECF had therapeutic consequences. Significant positive associations were found between age and smoking, respectively and the presence of ECFs. The cost estimate of saving one life from malignant disease based on ECF examinations is 40,190 Euro . Conclusion: Incidental extra-cardiac findings are common, sometimes revealing serious, even malignant disease. Diagnostic follow-up of major ECFs seems to be cost-effective in a Danish clinical setting. We recommend investigating a large field of view for incidental ECFs following CCT.

  14. A filtered backprojection reconstruction algorithm for Compton camera

    Energy Technology Data Exchange (ETDEWEB)

    Lojacono, Xavier; Maxim, Voichita; Peyrin, Francoise; Prost, Remy [Lyon Univ., Villeurbanne (France). CNRS, Inserm, INSA-Lyon, CREATIS, UMR5220; Zoglauer, Andreas [California Univ., Berkeley, CA (United States). Space Sciences Lab.

    2011-07-01

    In this paper we present a filtered backprojection reconstruction algorithm for Compton Camera detectors of particles. Compared to iterative methods, widely used for the reconstruction of images from Compton camera data, analytical methods are fast, easy to implement and avoid convergence issues. The method we propose is exact for an idealized Compton camera composed of two parallel plates of infinite dimension. We show that it copes well with low number of detected photons simulated from a realistic device. Images reconstructed from both synthetic data and realistic ones obtained with Monte Carlo simulations demonstrate the efficiency of the algorithm. (orig.)

  15. Characterization of the front-end EASIROC for read-out of SiPM in the ASTRI camera

    International Nuclear Information System (INIS)

    Impiombato, D.; Giarrusso, S.; Belluso, M.; Billotta, S.; Bonanno, G.; Catalano, O.; Grillo, A.; La Rosa, G.; Marano, D.; Mineo, T.; Russo, F.; Sottile, G.

    2013-01-01

    The design and realization of a prototype for the Small-Size class Telescopes of the Cherenkov Telescope Array is one of the cornerstones of the ASTRI project. The prototype will adopt a focal plane camera based on Silicon Photo-Multiplier sensors that coupled with a dual mirror optics configuration represents an innovative solution for the detection of Atmospheric Cherenkov light. These detectors can be read by the Extended Analogue Silicon Photo-Multiplier Integrated Read Out Chip (EASIROC) equipped with 32-channels. In this paper, we report some preliminary results on measurements aimed to evaluate EASIROC capability of autotriggering and measurements of the trigger time walk, jitter, DAC linearity and trigger efficiency vs the injected charge. Moreover, the dynamic range of the ASIC is also reported

  16. The NIKA2 Large Field-of-View Millimeter Continuum Camera for the 30-M IRAM Telescope

    Science.gov (United States)

    Monfardini, Alessandro

    2018-01-01

    We have constructed and deployed a multi-thousands pixels dual-band (150 and 260 GHz, respectively 2mm and 1.15mm wavelengths) camera to image an instantaneous field-of-view of 6.5arc-min and configurable to map the linear polarization at 260GHz. We are providing a detailed description of this instrument, named NIKA2 (New IRAM KID Arrays 2), in particular focusing on the cryogenics, the optics, the focal plane arrays based on Kinetic Inductance Detectors (KID) and the readout electronics. We are presenting the performance measured on the sky during the commissioning runs that took place between October 2015 and April 2017 at the 30-meter IRAM (Institute of Millimetric Radio Astronomy) telescope at Pico Veleta, and preliminary science-grade results.

  17. Quantitatively accurate activity measurements with a dedicated cardiac SPECT camera: Physical phantom experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pourmoghaddas, Amir, E-mail: apour@ottawaheart.ca; Wells, R. Glenn [Physics Department, Carleton University, Ottawa, Ontario K1S 5B6, Canada and Cardiology, The University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7 (Canada)

    2016-01-15

    Purpose: Recently, there has been increased interest in dedicated cardiac single photon emission computed tomography (SPECT) scanners with pinhole collimation and improved detector technology due to their improved count sensitivity and resolution over traditional parallel-hole cameras. With traditional cameras, energy-based approaches are often used in the clinic for scatter compensation because they are fast and easily implemented. Some of the cardiac cameras use cadmium-zinc-telluride (CZT) detectors which can complicate the use of energy-based scatter correction (SC) due to the low-energy tail—an increased number of unscattered photons detected with reduced energy. Modified energy-based scatter correction methods can be implemented, but their level of accuracy is unclear. In this study, the authors validated by physical phantom experiments the quantitative accuracy and reproducibility of easily implemented correction techniques applied to {sup 99m}Tc myocardial imaging with a CZT-detector-based gamma camera with multiple heads, each with a single-pinhole collimator. Methods: Activity in the cardiac compartment of an Anthropomorphic Torso phantom (Data Spectrum Corporation) was measured through 15 {sup 99m}Tc-SPECT acquisitions. The ratio of activity concentrations in organ compartments resembled a clinical {sup 99m}Tc-sestamibi scan and was kept consistent across all experiments (1.2:1 heart to liver and 1.5:1 heart to lung). Two background activity levels were considered: no activity (cold) and an activity concentration 1/10th of the heart (hot). A plastic “lesion” was placed inside of the septal wall of the myocardial insert to simulate the presence of a region without tracer uptake and contrast in this lesion was calculated for all images. The true net activity in each compartment was measured with a dose calibrator (CRC-25R, Capintec, Inc.). A 10 min SPECT image was acquired using a dedicated cardiac camera with CZT detectors (Discovery NM530c, GE

  18. Camera Trajectory fromWide Baseline Images

    Science.gov (United States)

    Havlena, M.; Torii, A.; Pajdla, T.

    2008-09-01

    angle θ of its corresponding rays w.r.t. the optical axis as θ = ar 1+br2 . After a successful calibration, we know the correspondence of the image points to the 3D optical rays in the coordinate system of the camera. The following steps aim at finding the transformation between the camera and the world coordinate systems, i.e. the pose of the camera in the 3D world, using 2D image matches. For computing 3D structure, we construct a set of tentative matches detecting different affine covariant feature regions including MSER, Harris Affine, and Hessian Affine in acquired images. These features are alternative to popular SIFT features and work comparably in our situation. Parameters of the detectors are chosen to limit the number of regions to 1-2 thousands per image. The detected regions are assigned local affine frames (LAF) and transformed into standard positions w.r.t. their LAFs. Discrete Cosine Descriptors are computed for each region in the standard position. Finally, mutual distances of all regions in one image and all regions in the other image are computed as the Euclidean distances of their descriptors and tentative matches are constructed by selecting the mutually closest pairs. Opposed to the methods using short baseline images, simpler image features which are not affine covariant cannot be used because the view point can change a lot between consecutive frames. Furthermore, feature matching has to be performed on the whole frame because no assumptions on the proximity of the consecutive projections can be made for wide baseline images. This is making the feature detection, description, and matching much more time-consuming than it is for short baseline images and limits the usage to low frame rate sequences when operating in real-time. Robust 3D structure can be computed by RANSAC which searches for the largest subset of the set of tentative matches which is, within a predefined threshold ", consistent with an epipolar geometry. We use ordered sampling as

  19. Silicon detectors

    International Nuclear Information System (INIS)

    Klanner, R.

    1984-08-01

    The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

  20. Long wavelength infrared camera (LWIRC): a 10 micron camera for the Keck Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Wishnow, E.H.; Danchi, W.C.; Tuthill, P.; Wurtz, R.; Jernigan, J.G.; Arens, J.F.

    1998-05-01

    The Long Wavelength Infrared Camera (LWIRC) is a facility instrument for the Keck Observatory designed to operate at the f/25 forward Cassegrain focus of the Keck I telescope. The camera operates over the wavelength band 7-13 {micro}m using ZnSe transmissive optics. A set of filters, a circular variable filter (CVF), and a mid-infrared polarizer are available, as are three plate scales: 0.05``, 0.10``, 0.21`` per pixel. The camera focal plane array and optics are cooled using liquid helium. The system has been refurbished with a 128 x 128 pixel Si:As detector array. The electronics readout system used to clock the array is compatible with both the hardware and software of the other Keck infrared instruments NIRC and LWS. A new pre-amplifier/A-D converter has been designed and constructed which decreases greatly the system susceptibility to noise.

  1. Directional Unfolded Source Term (DUST) for Compton Cameras.

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Dean J.; Mitchell, Dean J.; Horne, Steven M.; O' Brien, Sean; Thoreson, Gregory G

    2018-03-01

    A Directional Unfolded Source Term (DUST) algorithm was developed to enable improved spectral analysis capabilities using data collected by Compton cameras. Achieving this objective required modification of the detector response function in the Gamma Detector Response and Analysis Software (GADRAS). Experimental data that were collected in support of this work include measurements of calibration sources at a range of separation distances and cylindrical depleted uranium castings.

  2. Commercialization of radiation tolerant camera

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Bum; Choi, Young Soo; Kim, Sun Ku; Lee, Jong Min; Cha, Bung Hun; Lee, Nam Ho; Byun, Eiy Gyo; Yoo, Seun Wook; Choi, Bum Ki; Yoon, Sung Up; Kim, Hyun Gun; Sin, Jeong Hun; So, Suk Il

    1999-12-01

    In this project, radiation tolerant camera which tolerates 10{sup 6} - 10{sup 8} rad total dose is developed. In order to develop radiation tolerant camera, radiation effect of camera components was examined and evaluated, and camera configuration was studied. By the result of evaluation, the components were decided and design was performed. Vidicon tube was selected to use by image sensor and non-browning optics and camera driving circuit were applied. The controller needed for CCTV camera system, lens, light, pan/tilt controller, was designed by the concept of remote control. And two type of radiation tolerant camera were fabricated consider to use in underwater environment or normal environment. (author)

  3. Commercialization of radiation tolerant camera

    International Nuclear Information System (INIS)

    Lee, Yong Bum; Choi, Young Soo; Kim, Sun Ku; Lee, Jong Min; Cha, Bung Hun; Lee, Nam Ho; Byun, Eiy Gyo; Yoo, Seun Wook; Choi, Bum Ki; Yoon, Sung Up; Kim, Hyun Gun; Sin, Jeong Hun; So, Suk Il

    1999-12-01

    In this project, radiation tolerant camera which tolerates 10 6 - 10 8 rad total dose is developed. In order to develop radiation tolerant camera, radiation effect of camera components was examined and evaluated, and camera configuration was studied. By the result of evaluation, the components were decided and design was performed. Vidicon tube was selected to use by image sensor and non-browning optics and camera driving circuit were applied. The controller needed for CCTV camera system, lens, light, pan/tilt controller, was designed by the concept of remote control. And two type of radiation tolerant camera were fabricated consider to use in underwater environment or normal environment. (author)

  4. Selective-imaging camera

    Science.gov (United States)

    Szu, Harold; Hsu, Charles; Landa, Joseph; Cha, Jae H.; Krapels, Keith A.

    2015-05-01

    How can we design cameras that image selectively in Full Electro-Magnetic (FEM) spectra? Without selective imaging, we cannot use, for example, ordinary tourist cameras to see through fire, smoke, or other obscurants contributing to creating a Visually Degraded Environment (VDE). This paper addresses a possible new design of selective-imaging cameras at firmware level. The design is consistent with physics of the irreversible thermodynamics of Boltzmann's molecular entropy. It enables imaging in appropriate FEM spectra for sensing through the VDE, and displaying in color spectra for Human Visual System (HVS). We sense within the spectra the largest entropy value of obscurants such as fire, smoke, etc. Then we apply a smart firmware implementation of Blind Sources Separation (BSS) to separate all entropy sources associated with specific Kelvin temperatures. Finally, we recompose the scene using specific RGB colors constrained by the HVS, by up/down shifting Planck spectra at each pixel and time.

  5. Collimator trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    Jaszczak, Ronald J.

    1979-01-01

    An improved collimator is provided for a scintillation camera system that employs a detector head for transaxial tomographic scanning. One object of this invention is to significantly reduce the time required to obtain statistically significant data in radioisotope scanning using a scintillation camera. Another is to increase the rate of acceptance of radioactive events to contribute to the positional information obtainable from a radiation source of known strength without sacrificing spatial resolution. A further object is to reduce the necessary scanning time without degrading the images obtained. The collimator described has apertures defined by septa of different radiation transparency. The septa are aligned to provide greater radiation shielding from gamma radiation travelling within planes perpendicular to the cranial-caudal axis and less radiation shielding from gamma radiation travelling within other planes. Septa may also define apertures such that the collimator provides high spatial resolution of gamma rays traveling within planes perpendicular to the cranial-caudal axis and directed at the detector and high radiation sensitivity to gamma radiation travelling other planes and indicated at the detector. (LL)

  6. Toward standardising gamma camera quality control procedures

    International Nuclear Information System (INIS)

    Alkhorayef, M.A.; Alnaaimi, M.A.; Alduaij, M.A.; Mohamed, M.O.; Ibahim, S.Y.; Alkandari, F.A.; Bradley, D.A.

    2015-01-01

    Attaining high standards of efficiency and reliability in the practice of nuclear medicine requires appropriate quality control (QC) programs. For instance, the regular evaluation and comparison of extrinsic and intrinsic flood-field uniformity enables the quick correction of many gamma camera problems. Whereas QC tests for uniformity are usually performed by exposing the gamma camera crystal to a uniform flux of gamma radiation from a source of known activity, such protocols can vary significantly. Thus, there is a need for optimization and standardization, in part to allow direct comparison between gamma cameras from different vendors. In the present study, intrinsic uniformity was examined as a function of source distance, source activity, source volume and number of counts. The extrinsic uniformity and spatial resolution were also examined. Proper standard QC procedures need to be implemented because of the continual development of nuclear medicine imaging technology and the rapid expansion and increasing complexity of hybrid imaging system data. The present work seeks to promote a set of standard testing procedures to contribute to the delivery of safe and effective nuclear medicine services. - Highlights: • Optimal parameters for quality control of the gamma camera are proposed. • For extrinsic and intrinsic uniformity a minimum of 15,000 counts is recommended. • For intrinsic flood uniformity the activity should not exceed 100 µCi (3.7 MBq). • For intrinsic uniformity the source to detector distance should be at least 60 cm. • The bar phantom measurement must be performed with at least 15 million counts.

  7. Cervical SPECT Camera for Parathyroid Imaging

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2012-08-31

    Primary hyperparathyroidism characterized by one or more enlarged parathyroid glands has become one of the most common endocrine diseases in the world affecting about 1 per 1000 in the United States. Standard treatment is highly invasive exploratory neck surgery called Parathyroidectomy. The surgery has a notable mortality rate because of the close proximity to vital structures. The move to minimally invasive parathyroidectomy is hampered by the lack of high resolution pre-surgical imaging techniques that can accurately localize the parathyroid with respect to surrounding structures. We propose to develop a dedicated ultra-high resolution (~ 1 mm) and high sensitivity (10x conventional camera) cervical scintigraphic imaging device. It will be based on a multiple pinhole-camera SPECT system comprising a novel solid state CZT detector that offers the required performance. The overall system will be configured to fit around the neck and comfortably image a patient.

  8. The first GCT camera for the Cherenkov Telescope Array

    CERN Document Server

    De Franco, A.; Allan, D.; Armstrong, T.; Ashton, T.; Balzer, A.; Berge, D.; Bose, R.; Brown, A.M.; Buckley, J.; Chadwick, P.M.; Cooke, P.; Cotter, G.; Daniel, M.K.; Funk, S.; Greenshaw, T.; Hinton, J.; Kraus, M.; Lapington, J.; Molyneux, P.; Moore, P.; Nolan, S.; Okumura, A.; Ross, D.; Rulten, C.; Schmoll, J.; Schoorlemmer, H.; Stephan, M.; Sutcliffe, P.; Tajima, H.; Thornhill, J.; Tibaldo, L.; Varner, G.; Watson, J.; Zink, A.

    2015-01-01

    The Gamma Cherenkov Telescope (GCT) is proposed to be part of the Small Size Telescope (SST) array of the Cherenkov Telescope Array (CTA). The GCT dual-mirror optical design allows the use of a compact camera of diameter roughly 0.4 m. The curved focal plane is equipped with 2048 pixels of ~0.2{\\deg} angular size, resulting in a field of view of ~9{\\deg}. The GCT camera is designed to record the flashes of Cherenkov light from electromagnetic cascades, which last only a few tens of nanoseconds. Modules based on custom ASICs provide the required fast electronics, facilitating sampling and digitisation as well as first level of triggering. The first GCT camera prototype is currently being commissioned in the UK. On-telescope tests are planned later this year. Here we give a detailed description of the camera prototype and present recent progress with testing and commissioning.

  9. Automatic Camera Control

    DEFF Research Database (Denmark)

    Burelli, Paolo; Preuss, Mike

    2014-01-01

    Automatically generating computer animations is a challenging and complex problem with applications in games and film production. In this paper, we investigate howto translate a shot list for a virtual scene into a series of virtual camera configurations — i.e automatically controlling the virtual...

  10. World's fastest and most sensitive astronomical camera

    Science.gov (United States)

    2009-06-01

    The next generation of instruments for ground-based telescopes took a leap forward with the development of a new ultra-fast camera that can take 1500 finely exposed images per second even when observing extremely faint objects. The first 240x240 pixel images with the world's fastest high precision faint light camera were obtained through a collaborative effort between ESO and three French laboratories from the French Centre National de la Recherche Scientifique/Institut National des Sciences de l'Univers (CNRS/INSU). Cameras such as this are key components of the next generation of adaptive optics instruments of Europe's ground-based astronomy flagship facility, the ESO Very Large Telescope (VLT). ESO PR Photo 22a/09 The CCD220 detector ESO PR Photo 22b/09 The OCam camera ESO PR Video 22a/09 OCam images "The performance of this breakthrough camera is without an equivalent anywhere in the world. The camera will enable great leaps forward in many areas of the study of the Universe," says Norbert Hubin, head of the Adaptive Optics department at ESO. OCam will be part of the second-generation VLT instrument SPHERE. To be installed in 2011, SPHERE will take images of giant exoplanets orbiting nearby stars. A fast camera such as this is needed as an essential component for the modern adaptive optics instruments used on the largest ground-based telescopes. Telescopes on the ground suffer from the blurring effect induced by atmospheric turbulence. This turbulence causes the stars to twinkle in a way that delights poets, but frustrates astronomers, since it blurs the finest details of the images. Adaptive optics techniques overcome this major drawback, so that ground-based telescopes can produce images that are as sharp as if taken from space. Adaptive optics is based on real-time corrections computed from images obtained by a special camera working at very high speeds. Nowadays, this means many hundreds of times each second. The new generation instruments require these

  11. Camera network video summarization

    Science.gov (United States)

    Panda, Rameswar; Roy-Chowdhury, Amit K.

    2017-05-01

    Networks of vision sensors are deployed in many settings, ranging from security needs to disaster response to environmental monitoring. Many of these setups have hundreds of cameras and tens of thousands of hours of video. The difficulty of analyzing such a massive volume of video data is apparent whenever there is an incident that requires foraging through vast video archives to identify events of interest. As a result, video summarization, that automatically extract a brief yet informative summary of these videos, has attracted intense attention in the recent years. Much progress has been made in developing a variety of ways to summarize a single video in form of a key sequence or video skim. However, generating a summary from a set of videos captured in a multi-camera network still remains as a novel and largely under-addressed problem. In this paper, with the aim of summarizing videos in a camera network, we introduce a novel representative selection approach via joint embedding and capped l21-norm minimization. The objective function is two-fold. The first is to capture the structural relationships of data points in a camera network via an embedding, which helps in characterizing the outliers and also in extracting a diverse set of representatives. The second is to use a capped l21-norm to model the sparsity and to suppress the influence of data outliers in representative selection. We propose to jointly optimize both of the objectives, such that embedding can not only characterize the structure, but also indicate the requirements of sparse representative selection. Extensive experiments on standard multi-camera datasets well demonstrate the efficacy of our method over state-of-the-art methods.

  12. Limited-angle imaging in positron cameras: theory and practice

    International Nuclear Information System (INIS)

    Tam, K.C.

    1979-10-01

    The principles of operation of planar positron camera systems made up of multiwire proportional chambers as detectors and electromagnetic delay lines for coordinate readout are discussed. Gamma converters are coupled to the wire chambers to increase detection efficiency and improve spatial resolution. The conversion efficiencies of these converters are calculated and the results compare favorably to the experimentally measured values

  13. Limited-angle imaging in positron cameras: theory and practice

    Energy Technology Data Exchange (ETDEWEB)

    Tam, K.C.

    1979-10-01

    The principles of operation of planar positron camera systems made up of multiwire proportional chambers as detectors and electromagnetic delay lines for coordinate readout are discussed. Gamma converters are coupled to the wire chambers to increase detection efficiency and improve spatial resolution. The conversion efficiencies of these converters are calculated and the results compare favorably to the experimentally measured values.

  14. Dual Regression

    OpenAIRE

    Spady, Richard; Stouli, Sami

    2012-01-01

    We propose dual regression as an alternative to the quantile regression process for the global estimation of conditional distribution functions under minimal assumptions. Dual regression provides all the interpretational power of the quantile regression process while avoiding the need for repairing the intersecting conditional quantile surfaces that quantile regression often produces in practice. Our approach introduces a mathematical programming characterization of conditional distribution f...

  15. Modeling and simulation of gamma camera

    International Nuclear Information System (INIS)

    Singh, B.; Kataria, S.K.; Samuel, A.M.

    2002-08-01

    Simulation techniques play a vital role in designing of sophisticated instruments and also for the training of operating and maintenance staff. Gamma camera systems have been used for functional imaging in nuclear medicine. Functional images are derived from the external counting of the gamma emitting radioactive tracer that after introduction in to the body mimics the behavior of native biochemical compound. The position sensitive detector yield the coordinates of the gamma ray interaction with the detector and are used to estimate the point of gamma ray emission within the tracer distribution space. This advanced imaging device is thus dependent on the performance of algorithm for coordinate computing, estimation of point of emission, generation of image and display of the image data. Contemporary systems also have protocols for quality control and clinical evaluation of imaging studies. Simulation of this processing leads to understanding of the basic camera design problems. This report describes a PC based package for design and simulation of gamma camera along with the options of simulating data acquisition and quality control of imaging studies. Image display and data processing the other options implemented in SIMCAM will be described in separate reports (under preparation). Gamma camera modeling and simulation in SIMCAM has preset configuration of the design parameters for various sizes of crystal detector with the option to pack the PMT on hexagon or square lattice. Different algorithm for computation of coordinates and spatial distortion removal are allowed in addition to the simulation of energy correction circuit. The user can simulate different static, dynamic, MUGA and SPECT studies. The acquired/ simulated data is processed for quality control and clinical evaluation of the imaging studies. Results show that the program can be used to assess these performances. Also the variations in performance parameters can be assessed due to the induced

  16. Collimator trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    Jaszczak, R.J.

    1977-01-01

    A collimator is provided for a scintillation camera system in which a detector precesses in an orbit about a patient. The collimator is designed to have high resolution and lower sensitivity with respect to radiation traveling in paths laying wholly within planes perpendicular to the cranial-caudal axis of the patient. The collimator has high sensitivity and lower resolution to radiation traveling in other planes. Variances in resolution and sensitivity are achieved by altering the length, spacing or thickness of the septa of the collimator

  17. The Compton Camera - medical imaging with higher sensitivity Exhibition LEPFest 2000

    CERN Multimedia

    2000-01-01

    The Compton Camera reconstructs the origin of Compton-scattered X-rays using electronic collimation with Silicon pad detectors instead of the heavy conventional lead collimators in Anger cameras - reaching up to 200 times better sensitivity and a factor two improvement in resolution. Possible applications are in cancer diagnosis, neurology neurobiology, and cardiology.

  18. A novel fully integrated handheld gamma camera

    International Nuclear Information System (INIS)

    Massari, R.; Ucci, A.; Campisi, C.; Scopinaro, F.; Soluri, A.

    2016-01-01

    In this paper, we present an innovative, fully integrated handheld gamma camera, namely designed to gather in the same device the gamma ray detector with the display and the embedded computing system. The low power consumption allows the prototype to be battery operated. To be useful in radioguided surgery, an intraoperative gamma camera must be very easy to handle since it must be moved to find a suitable view. Consequently, we have developed the first prototype of a fully integrated, compact and lightweight gamma camera for radiopharmaceuticals fast imaging. The device can operate without cables across the sterile field, so it may be easily used in the operating theater for radioguided surgery. The prototype proposed consists of a Silicon Photomultiplier (SiPM) array coupled with a proprietary scintillation structure based on CsI(Tl) crystals. To read the SiPM output signals, we have developed a very low power readout electronics and a dedicated analog to digital conversion system. One of the most critical aspects we faced designing the prototype was the low power consumption, which is mandatory to develop a battery operated device. We have applied this detection device in the lymphoscintigraphy technique (sentinel lymph node mapping) comparing the results obtained with those of a commercial gamma camera (Philips SKYLight). The results obtained confirm a rapid response of the device and an adequate spatial resolution for the use in the scintigraphic imaging. This work confirms the feasibility of a small gamma camera with an integrated display. This device is designed for radioguided surgery and small organ imaging, but it could be easily combined into surgical navigation systems.

  19. A novel fully integrated handheld gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Massari, R.; Ucci, A.; Campisi, C. [Biostructure and Bioimaging Institute (IBB), National Research Council of Italy (CNR), Rome (Italy); Scopinaro, F. [University of Rome “La Sapienza”, S. Andrea Hospital, Rome (Italy); Soluri, A., E-mail: alessandro.soluri@ibb.cnr.it [Biostructure and Bioimaging Institute (IBB), National Research Council of Italy (CNR), Rome (Italy)

    2016-10-01

    In this paper, we present an innovative, fully integrated handheld gamma camera, namely designed to gather in the same device the gamma ray detector with the display and the embedded computing system. The low power consumption allows the prototype to be battery operated. To be useful in radioguided surgery, an intraoperative gamma camera must be very easy to handle since it must be moved to find a suitable view. Consequently, we have developed the first prototype of a fully integrated, compact and lightweight gamma camera for radiopharmaceuticals fast imaging. The device can operate without cables across the sterile field, so it may be easily used in the operating theater for radioguided surgery. The prototype proposed consists of a Silicon Photomultiplier (SiPM) array coupled with a proprietary scintillation structure based on CsI(Tl) crystals. To read the SiPM output signals, we have developed a very low power readout electronics and a dedicated analog to digital conversion system. One of the most critical aspects we faced designing the prototype was the low power consumption, which is mandatory to develop a battery operated device. We have applied this detection device in the lymphoscintigraphy technique (sentinel lymph node mapping) comparing the results obtained with those of a commercial gamma camera (Philips SKYLight). The results obtained confirm a rapid response of the device and an adequate spatial resolution for the use in the scintigraphic imaging. This work confirms the feasibility of a small gamma camera with an integrated display. This device is designed for radioguided surgery and small organ imaging, but it could be easily combined into surgical navigation systems.

  20. Transmutation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Viererbl, L., E-mail: vie@ujv.c [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic); Lahodova, Z. [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic); Klupak, V. [Nuclear Research Institute Rez plc (Czech Republic); Sus, F. [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic); Kucera, J. [Research Centre Rez Ltd. (Czech Republic); Nuclear Physics Institute, Academy of Sciences of the Czech Republic (Czech Republic); Kus, P.; Marek, M. [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic)

    2011-03-11

    We have designed a new type of detectors, called transmutation detectors, which can be used primarily for neutron fluence measurement. The transmutation detector method differs from the commonly used activation detector method in evaluation of detector response after irradiation. Instead of radionuclide activity measurement using radiometric methods, the concentration of stable non-gaseous nuclides generated by transmutation in the detector is measured using analytical methods like mass spectrometry. Prospective elements and nuclear reactions for transmutation detectors are listed and initial experimental results are given. The transmutation detector method could be used primarily for long-term measurement of neutron fluence in fission nuclear reactors, but in principle it could be used for any type of radiation that can cause transmutation of nuclides in detectors. This method could also be used for measurement in accelerators or fusion reactors.

  1. Transmutation detectors

    International Nuclear Information System (INIS)

    Viererbl, L.; Lahodova, Z.; Klupak, V.; Sus, F.; Kucera, J.; Kus, P.; Marek, M.

    2011-01-01

    We have designed a new type of detectors, called transmutation detectors, which can be used primarily for neutron fluence measurement. The transmutation detector method differs from the commonly used activation detector method in evaluation of detector response after irradiation. Instead of radionuclide activity measurement using radiometric methods, the concentration of stable non-gaseous nuclides generated by transmutation in the detector is measured using analytical methods like mass spectrometry. Prospective elements and nuclear reactions for transmutation detectors are listed and initial experimental results are given. The transmutation detector method could be used primarily for long-term measurement of neutron fluence in fission nuclear reactors, but in principle it could be used for any type of radiation that can cause transmutation of nuclides in detectors. This method could also be used for measurement in accelerators or fusion reactors.

  2. NSTX Tangential Divertor Camera

    International Nuclear Information System (INIS)

    Roquemore, A.L.; Ted Biewer; Johnson, D.; Zweben, S.J.; Nobuhiro Nishino; Soukhanovskii, V.A.

    2004-01-01

    Strong magnetic field shear around the divertor x-point is numerically predicted to lead to strong spatial asymmetries in turbulence driven particle fluxes. To visualize the turbulence and associated impurity line emission near the lower x-point region, a new tangential observation port has been recently installed on NSTX. A reentrant sapphire window with a moveable in-vessel mirror images the divertor region from the center stack out to R 80 cm and views the x-point for most plasma configurations. A coherent fiber optic bundle transmits the image through a remotely selected filter to a fast camera, for example a 40500 frames/sec Photron CCD camera. A gas puffer located in the lower inboard divertor will localize the turbulence in the region near the x-point. Edge fluid and turbulent codes UEDGE and BOUT will be used to interpret impurity and deuterium emission fluctuation measurements in the divertor

  3. Ensuring long-term stability of infrared camera absolute calibration.

    Science.gov (United States)

    Kattnig, Alain; Thetas, Sophie; Primot, Jérôme

    2015-07-13

    Absolute calibration of cryogenic 3-5 µm and 8-10 µm infrared cameras is notoriously instable and thus has to be repeated before actual measurements. Moreover, the signal to noise ratio of the imagery is lowered, decreasing its quality. These performances degradations strongly lessen the suitability of Infrared Imaging. These defaults are often blamed on detectors reaching a different "response state" after each return to cryogenic conditions, while accounting for the detrimental effects of imperfect stray light management. We show here that detectors are not to be blamed and that the culprit can also dwell in proximity electronics. We identify an unexpected source of instability in the initial voltage of the integrating capacity of detectors. Then we show that this parameter can be easily measured and taken into account. This way we demonstrate that a one month old calibration of a 3-5 µm camera has retained its validity.

  4. Miniature gamma-ray camera for tumor localization

    International Nuclear Information System (INIS)

    Lund, J.C.; Olsen, R.W.; James, R.B.; Cross, E.

    1997-08-01

    The overall goal of this LDRD project was to develop technology for a miniature gamma-ray camera for use in nuclear medicine. The camera will meet a need of the medical community for an improved means to image radio-pharmaceuticals in the body. In addition, this technology-with only slight modifications-should prove useful in applications requiring the monitoring and verification of special nuclear materials (SNMs). Utilization of the good energy resolution of mercuric iodide and cadmium zinc telluride detectors provides a means for rejecting scattered gamma-rays and improving the isotopic selectivity in gamma-ray images. The first year of this project involved fabrication and testing of a monolithic mercuric iodide and cadmium zinc telluride detector arrays and appropriate collimators/apertures. The second year of the program involved integration of the front-end detector module, pulse processing electronics, computer, software, and display

  5. Gamma camera display system

    International Nuclear Information System (INIS)

    Stout, K.J.

    1976-01-01

    A gamma camera having an array of photomultipliers coupled via pulse shaping circuitry and a resistor weighting circuit to a display for forming an image of a radioactive subject is described. A linearizing circuit is coupled to the weighting circuit, the linearizing circuit including a nonlinear feedback circuit with diode coupling to the weighting circuit for linearizing the correspondence between points of the display and points of the subject. 4 Claims, 5 Drawing Figures

  6. Comparison of polarimetric cameras

    Science.gov (United States)

    2017-03-01

    Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget , Paperwork Reduction Project (0704-0188...polarimetric camera, remote sensing, space systems 15. NUMBER OF PAGES 93 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18...2016. Hermann Hall, Monterey, CA. The next data in Figure 37. were collected on 01 December 2016 at 1226 PST on the rooftop of the Marriot Hotel in

  7. Optical registration of spaceborne low light remote sensing camera

    Science.gov (United States)

    Li, Chong-yang; Hao, Yan-hui; Xu, Peng-mei; Wang, Dong-jie; Ma, Li-na; Zhao, Ying-long

    2018-02-01

    For the high precision requirement of spaceborne low light remote sensing camera optical registration, optical registration of dual channel for CCD and EMCCD is achieved by the high magnification optical registration system. System integration optical registration and accuracy of optical registration scheme for spaceborne low light remote sensing camera with short focal depth and wide field of view is proposed in this paper. It also includes analysis of parallel misalignment of CCD and accuracy of optical registration. Actual registration results show that imaging clearly, MTF and accuracy of optical registration meet requirements, it provide important guarantee to get high quality image data in orbit.

  8. Extended spectrum SWIR camera with user-accessible Dewar

    Science.gov (United States)

    Benapfl, Brendan; Miller, John Lester; Vemuri, Hari; Grein, Christoph; Sivananthan, Siva

    2017-02-01

    Episensors has developed a series of extended short wavelength infrared (eSWIR) cameras based on high-Cd concentration Hg1-xCdxTe absorbers. The cameras have a bandpass extending to 3 microns cutoff wavelength, opening new applications relative to traditional InGaAs-based cameras. Applications and uses are discussed and examples given. A liquid nitrogen pour-filled version was initially developed. This was followed by a compact Stirling-cooled version with detectors operating at 200 K. Each camera has unique sensitivity and performance characteristics. The cameras' size, weight and power specifications are presented along with images captured with band pass filters and eSWIR sources to demonstrate spectral response beyond 1.7 microns. The soft seal Dewars of the cameras are designed for accessibility, and can be opened and modified in a standard laboratory environment. This modular approach allows user flexibility for swapping internal components such as cold filters and cold stops. The core electronics of the Stirlingcooled camera are based on a single commercial field programmable gate array (FPGA) that also performs on-board non-uniformity corrections, bad pixel replacement, and directly drives any standard HDMI display.

  9. Crystal Compton Camera

    Energy Technology Data Exchange (ETDEWEB)

    Ziock, Klaus-Peter [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Braverman, Joshua B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Harrison, Mark J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hornback, Donald Eric [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fabris, Lorenzo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Newby, Jason [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2013-09-26

    Stand-off detection is one of the most important radiation detection capabilities for arms control and the control of illicit nuclear materials. For long range passive detection one requires a large detector and a means of “seeing through” the naturally occurring and varying background radiation, i.e. imaging. Arguably, Compton imaging is the best approach over much of the emission band suitable for long range detection. It provides not only imaging, but more information about the direction of incidence of each detected gamma-ray than the alternate approach of coded-aperture imaging. The directional information allows one to reduce the background and hence improve the sensitivity of a measurement. However, to make an efficient Compton imager requires localizing and measuring the simultaneous energy depositions when gamma-rays Compton scatter and are subsequently captured within a single, large detector volume. This concept has been demonstrated in semi-conductor detectors (HPGe, CZT, Si) but at ~ $1k/cm3 these materials are too expensive to build the large systems needed for standoff detection. Scintillator detectors, such as NaI(Tl), are two orders of magnitude less expensive and possess the energy resolution required to make such an imager. However, they do not currently have the ability to localize closely spaced, simultaneous energy depositions in a single large crystal. In this project we are applying a new technique that should, for the first time ever, allow cubic-millimeter event localization in a bulk scintillator crystal.

  10. Detector Unit

    CERN Multimedia

    1960-01-01

    Original detector unit of the Instituut voor Kernfysisch Onderzoek (IKO) BOL project. This detector unit shows that silicon detectors for nuclear physics particle detection were already developed and in use in the 1960's in Amsterdam. Also the idea of putting 'strips' onto the silicon for high spatial resolution of a particle's impact on the detector were implemented in the BOL project which used 64 of these detector units. The IKO BOL project with its silicon particle detectors was designed, built and operated from 1965 to roughly 1977. Detector Unit of the BOL project: These detectors, notably the ‘checkerboard detector’, were developed during the years 1964-1968 in Amsterdam, The Netherlands, by the Natuurkundig Laboratorium of the N.V. Philips Gloeilampen Fabrieken. This was done in close collaboration with the Instituut voor Kernfysisch Onderzoek (IKO) where the read-out electronics for their use in the BOL Project was developed and produced.

  11. Detector trends

    International Nuclear Information System (INIS)

    Charpak, G.

    1986-01-01

    The author describes briefly the development of detectors for high energy physics experiments. Especially considered are semiconductor microstrip detectors, drift tubes, holographic bubble chambers, scintillating fiber optics, and calorimeters. (HSI).

  12. Hubble Space Telescope, Faint Object Camera

    Science.gov (United States)

    1981-01-01

    This drawing illustrates Hubble Space Telescope's (HST's), Faint Object Camera (FOC). The FOC reflects light down one of two optical pathways. The light enters a detector after passing through filters or through devices that can block out light from bright objects. Light from bright objects is blocked out to enable the FOC to see background images. The detector intensifies the image, then records it much like a television camera. For faint objects, images can be built up over long exposure times. The total image is translated into digital data, transmitted to Earth, and then reconstructed. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors.

  13. Radiation-resistant camera tube

    International Nuclear Information System (INIS)

    Kuwahata, Takao; Manabe, Sohei; Makishima, Yasuhiro

    1982-01-01

    It was a long time ago that Toshiba launched on manufacturing black-and-white radiation-resistant camera tubes employing nonbrowning face-plate glass for ITV cameras used in nuclear power plants. Now in compliance with the increasing demand in nuclear power field, the Company is at grips with the development of radiation-resistant single color-camera tubes incorporating a color-stripe filter for color ITV cameras used under radiation environment. Herein represented are the results of experiments on characteristics of materials for single color-camera tubes and prospects for commercialization of the tubes. (author)

  14. New detection modules for gamma, beta and X-ray cameras

    International Nuclear Information System (INIS)

    Azman, S.; Bolle, E.; Dang, K.Q.; Dang, W.; Dietzel, K.I.; Froberg, T.; Gaarder, P.E.; Gjaerum, J.A.; Haugen, S.H.; Hellum, G.; Henriksen, J.R.; Johanson, T.M.; Kobbevik, A.; Maehlum, G.; Meier, D.; Mikkelsen, S.; Ninive, I.; Oya, P.; Pavlov, N.; Pettersen, D.M.; Sundal, B.M.; Talebi, J.; Yoshioka, K.

    2003-01-01

    Full text: Ideas ASA is developing new detection modules for gamma, beta and X-ray cameras. Recent developments focus on modules using various semi-conductor materials (CZT, HgI, Si). The development includes ASIC design, detector module development, and implementation in camera heads. In this presentation we describe the characteristics of important ASICs and its properties in terms of electronic noise, and the modes for measuring signals (switched current modes, sparsified modes, self triggered modes). The ASICs are specific for detectors and applications. We describe recent developments using various semi - conductor materials. We describe important design aspects for medical applications and in life science (SPECT, beta, X-ray cameras)

  15. Infrared detectors

    CERN Document Server

    Rogalski, Antonio

    2010-01-01

    This second edition is fully revised and reorganized, with new chapters concerning third generation and quantum dot detectors, THz detectors, cantilever and antenna coupled detectors, and information on radiometry and IR optics materials. Part IV concerning focal plane arrays is significantly expanded. This book, resembling an encyclopedia of IR detectors, is well illustrated and contains many original references … a really comprehensive book.-F. Sizov, Institute of Semiconductor Physics, National Academy of Sciences, Kiev, Ukraine

  16. Improvement of passive THz camera images

    Science.gov (United States)

    Kowalski, Marcin; Piszczek, Marek; Palka, Norbert; Szustakowski, Mieczyslaw

    2012-10-01

    Terahertz technology is one of emerging technologies that has a potential to change our life. There are a lot of attractive applications in fields like security, astronomy, biology and medicine. Until recent years, terahertz (THz) waves were an undiscovered, or most importantly, an unexploited area of electromagnetic spectrum. The reasons of this fact were difficulties in generation and detection of THz waves. Recent advances in hardware technology have started to open up the field to new applications such as THz imaging. The THz waves can penetrate through various materials. However, automated processing of THz images can be challenging. The THz frequency band is specially suited for clothes penetration because this radiation does not point any harmful ionizing effects thus it is safe for human beings. Strong technology development in this band have sparked with few interesting devices. Even if the development of THz cameras is an emerging topic, commercially available passive cameras still offer images of poor quality mainly because of its low resolution and low detectors sensitivity. Therefore, THz image processing is very challenging and urgent topic. Digital THz image processing is a really promising and cost-effective way for demanding security and defense applications. In the article we demonstrate the results of image quality enhancement and image fusion of images captured by a commercially available passive THz camera by means of various combined methods. Our research is focused on dangerous objects detection - guns, knives and bombs hidden under some popular types of clothing.

  17. Camera Movement in Narrative Cinema

    DEFF Research Database (Denmark)

    Nielsen, Jakob Isak

    2007-01-01

    section unearths what characterizes the literature on camera movement. The second section of the dissertation delineates the history of camera movement itself within narrative cinema. Several organizational principles subtending the on-screen effect of camera movement are revealed in section two...... but they are not organized into a coherent framework. This is the task that section three meets in proposing a functional taxonomy for camera movement in narrative cinema. Two presumptions subtend the taxonomy: That camera movement actively contributes to the way in which we understand the sound and images on the screen......, commentative or valuative manner. 4) Focalization: associating the movement of the camera with the viewpoints of characters or entities in the story world. 5) Reflexive: inviting spectators to engage with the artifice of camera movement. 6) Abstract: visualizing abstract ideas and concepts. In order...

  18. Precision synchrotron radiation detectors

    International Nuclear Information System (INIS)

    Levi, M.; Rouse, F.; Butler, J.

    1989-03-01

    Precision detectors to measure synchrotron radiation beam positions have been designed and installed as part of beam energy spectrometers at the Stanford Linear Collider (SLC). The distance between pairs of synchrotron radiation beams is measured absolutely to better than 28 /mu/m on a pulse-to-pulse basis. This contributes less than 5 MeV to the error in the measurement of SLC beam energies (approximately 50 GeV). A system of high-resolution video cameras viewing precisely-aligned fiducial wire arrays overlaying phosphorescent screens has achieved this accuracy. Also, detectors of synchrotron radiation using the charge developed by the ejection of Compton-recoil electrons from an array of fine wires are being developed. 4 refs., 5 figs., 1 tab

  19. Comparison of myocardial perfusion imaging between the new high-speed gamma camera and the standard anger camera

    International Nuclear Information System (INIS)

    Tanaka, Hirokazu; Chikamori, Taishiro; Hida, Satoshi

    2013-01-01

    Cadmium-zinc-telluride (CZT) solid-state detectors have been recently introduced into the field of myocardial perfusion imaging. The aim of this study was to prospectively compare the diagnostic performance of the CZT high-speed gamma camera (Discovery NM 530c) with that of the standard 3-head gamma camera in the same group of patients. The study group consisted of 150 consecutive patients who underwent a 1-day stress-rest 99m Tc-sestamibi or tetrofosmin imaging protocol. Image acquisition was performed first on a standard gamma camera with a 15-min scan time each for stress and for rest. All scans were immediately repeated on a CZT camera with a 5-min scan time for stress and a 3-min scan time for rest, using list mode. The correlations between the CZT camera and the standard camera for perfusion and function analyses were strong within narrow Bland-Altman limits of agreement. Using list mode analysis, image quality for stress was rated as good or excellent in 97% of the 3-min scans, and in 100% of the ≥4-min scans. For CZT scans at rest, similarly, image quality was rated as good or excellent in 94% of the 1-min scans, and in 100% of the ≥2-min scans. The novel CZT camera provides excellent image quality, which is equivalent to standard myocardial single-photon emission computed tomography, despite a short scan time of less than half of the standard time. (author)

  20. A novel method for assessing position-sensitive detector performance

    International Nuclear Information System (INIS)

    Clinthorne, N.H.; Rogers, W.L.; Shao, L.; Hero, A.O. III; Koral, K.F.

    1989-01-01

    A marked point process model of a position-sensitive detector is developed which includes the effects of detector efficiency, spatial response, energy response, and source statistics. The average mutual information between the incident distribution of γ rays and the detector response is derived and used as a performance index for detector optimization. A brief example is presented which uses this figure-of-merit for optimization of light guide dimensions for a modular scintillation camera

  1. Image Mosaicking Approach for a Double-Camera System in the GaoFen2 Optical Remote Sensing Satellite Based on the Big Virtual Camera.

    Science.gov (United States)

    Cheng, Yufeng; Jin, Shuying; Wang, Mi; Zhu, Ying; Dong, Zhipeng

    2017-06-20

    The linear array push broom imaging mode is widely used for high resolution optical satellites (HROS). Using double-cameras attached by a high-rigidity support along with push broom imaging is one method to enlarge the field of view while ensuring high resolution. High accuracy image mosaicking is the key factor of the geometrical quality of complete stitched satellite imagery. This paper proposes a high accuracy image mosaicking approach based on the big virtual camera (BVC) in the double-camera system on the GaoFen2 optical remote sensing satellite (GF2). A big virtual camera can be built according to the rigorous imaging model of a single camera; then, each single image strip obtained by each TDI-CCD detector can be re-projected to the virtual detector of the big virtual camera coordinate system using forward-projection and backward-projection to obtain the corresponding single virtual image. After an on-orbit calibration and relative orientation, the complete final virtual image can be obtained by stitching the single virtual images together based on their coordinate information on the big virtual detector image plane. The paper subtly uses the concept of the big virtual camera to obtain a stitched image and the corresponding high accuracy rational function model (RFM) for concurrent post processing. Experiments verified that the proposed method can achieve seamless mosaicking while maintaining the geometric accuracy.

  2. 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...

  3. Binary pressure-sensitive paint measurements using miniaturised, colour, machine vision cameras

    Science.gov (United States)

    Quinn, Mark Kenneth

    2018-05-01

    Recent advances in machine vision technology and capability have led to machine vision cameras becoming applicable for scientific imaging. This study aims to demonstrate the applicability of machine vision colour cameras for the measurement of dual-component pressure-sensitive paint (PSP). The presence of a second luminophore component in the PSP mixture significantly reduces its inherent temperature sensitivity, increasing its applicability at low speeds. All of the devices tested are smaller than the cooled CCD cameras traditionally used and most are of significantly lower cost, thereby increasing the accessibility of such technology and techniques. Comparisons between three machine vision cameras, a three CCD camera, and a commercially available specialist PSP camera are made on a range of parameters, and a detailed PSP calibration is conducted in a static calibration chamber. The findings demonstrate that colour machine vision cameras can be used for quantitative, dual-component, pressure measurements. These results give rise to the possibility of performing on-board dual-component PSP measurements in wind tunnels or on real flight/road vehicles.

  4. A Portable, Inexpensive, Nonmydriatic Fundus Camera Based on the Raspberry Pi® Computer

    Directory of Open Access Journals (Sweden)

    Bailey Y. Shen

    2017-01-01

    Full Text Available Purpose. Nonmydriatic fundus cameras allow retinal photography without pharmacologic dilation of the pupil. However, currently available nonmydriatic fundus cameras are bulky, not portable, and expensive. Taking advantage of recent advances in mobile technology, we sought to create a nonmydriatic fundus camera that was affordable and could be carried in a white coat pocket. Methods. We built a point-and-shoot prototype camera using a Raspberry Pi computer, an infrared-sensitive camera board, a dual infrared and white light light-emitting diode, a battery, a 5-inch touchscreen liquid crystal display, and a disposable 20-diopter condensing lens. Our prototype camera was based on indirect ophthalmoscopy with both infrared and white lights. Results. The prototype camera measured 133mm×91mm×45mm and weighed 386 grams. The total cost of the components, including the disposable lens, was $185.20. The camera was able to obtain good-quality fundus images without pharmacologic dilation of the pupils. Conclusion. A fully functional, inexpensive, handheld, nonmydriatic fundus camera can be easily assembled from a relatively small number of components. With modest improvements, such a camera could be useful for a variety of healthcare professionals, particularly those who work in settings where a traditional table-mounted nonmydriatic fundus camera would be inconvenient.

  5. Automatic inference of geometric camera parameters and inter-camera topology in uncalibrated disjoint surveillance cameras

    Science.gov (United States)

    den Hollander, Richard J. M.; Bouma, Henri; Baan, Jan; Eendebak, Pieter T.; van Rest, Jeroen H. C.

    2015-10-01

    Person tracking across non-overlapping cameras and other types of video analytics benefit from spatial calibration information that allows an estimation of the distance between cameras and a relation between pixel coordinates and world coordinates within a camera. In a large environment with many cameras, or for frequent ad-hoc deployments of cameras, the cost of this calibration is high. This creates a barrier for the use of video analytics. Automating the calibration allows for a short configuration time, and the use of video analytics in a wider range of scenarios, including ad-hoc crisis situations and large scale surveillance systems. We show an autocalibration method entirely based on pedestrian detections in surveillance video in multiple non-overlapping cameras. In this paper, we show the two main components of automatic calibration. The first shows the intra-camera geometry estimation that leads to an estimate of the tilt angle, focal length and camera height, which is important for the conversion from pixels to meters and vice versa. The second component shows the inter-camera topology inference that leads to an estimate of the distance between cameras, which is important for spatio-temporal analysis of multi-camera tracking. This paper describes each of these methods and provides results on realistic video data.

  6. The Explicit Determinations Of Dual Plane Curves And Dual Helices In Terms Of Its Dual Curvature And Dual Torsion

    OpenAIRE

    Lee Jae Won; Choi Jin Ho; Jin Dae Ho

    2014-01-01

    In this paper, we give the explicit determinations of dual plane curves, general dual helices and dual slant helices in terms of its dual curvature and dual torsion as a fundamental theory of dual curves in a dual 3-space

  7. Design and Construction of an X-ray Lightning Camera

    Science.gov (United States)

    Schaal, M.; Dwyer, J. R.; Rassoul, H. K.; Uman, M. A.; Jordan, D. M.; Hill, J. D.

    2010-12-01

    A pinhole-type camera was designed and built for the purpose of producing high-speed images of the x-ray emissions from rocket-and-wire-triggered lightning. The camera consists of 30 7.62-cm diameter NaI(Tl) scintillation detectors, each sampling at 10 million frames per second. The steel structure of the camera is encased in 1.27-cm thick lead, which blocks x-rays that are less than 400 keV, except through a 7.62-cm diameter “pinhole” aperture located at the front of the camera. The lead and steel structure is covered in 0.16-cm thick aluminum to block RF noise, water and light. All together, the camera weighs about 550-kg and is approximately 1.2-m x 0.6-m x 0.6-m. The image plane, which is adjustable, was placed 32-cm behind the pinhole aperture, giving a field of view of about ±38° in both the vertical and horizontal directions. The elevation of the camera is adjustable between 0 and 50° from horizontal and the camera may be pointed in any azimuthal direction. In its current configuration, the camera’s angular resolution is about 14°. During the summer of 2010, the x-ray camera was located 44-m from the rocket-launch tower at the UF/Florida Tech International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, FL and several rocket-triggered lightning flashes were observed. In this presentation, I will discuss the design, construction and operation of this x-ray camera.

  8. SU-G-IeP3-10: Molecular Imaging with Clinical X-Ray Sources and Compton Cameras

    International Nuclear Information System (INIS)

    Vernekohl, D; Ahmad, M; Chinn, G; Xing, L

    2016-01-01

    Purpose: The application of Compton cameras (CC) is a novel approach translating XFCT to a practical modality realized with clinical CT systems without the restriction of pencil beams. The dual modality design offers additional information without extra patient dose. The purpose of this work is to investigate the feasibility and efficacy of using CCs for volumetric x-ray fluorescence (XF) imaging by Monte Carlo (MC) simulations and statistical image reconstruction. Methods: The feasibility of a CC for imaging x-ray fluorescence emitted from targeted lesions is examined by MC simulations. 3 mm diameter water spheres with various gold concentrations and detector distances are placed inside the lung of an adult human phantom (MIRD) and are irradiated with both fan and cone-beam geometries. A sandwich design CC composed of Silicon and CdTe is used to image the gold nanoparticle distribution. The detection system comprises four 16×26 cm"2 detector panels placed on the chest of a MIRD phantom. Constraints of energy-, spatial-resolution, clinical geometries and Doppler broadening are taken into account. Image reconstruction is performed with a list-mode MLEM algorithm with cone-projector on a GPU. Results: The comparison of reconstruction of cone- and fan-beam excitation shows that the spatial resolution is improved by 23% for fan-beams with significantly decreased processing time. Cone-beam excitation increases scatter content disturbing quantification of lesions near the body surface. Spatial resolution and detectability limit in the center of the lung is 8.7 mm and 20 fM for 50 nm diameter gold nanoparticles at 20 mGy. Conclusion: The implementation of XFCT with a CC is a feasible method for molecular imaging with high atomic number probes. Given constrains of detector resolutions, Doppler broadening, and limited exposure dose, spatial resolutions comparable with PET and molecular sensitivities in the fM range are realizable with current detector technology.

  9. SU-G-IeP3-10: Molecular Imaging with Clinical X-Ray Sources and Compton Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Vernekohl, D; Ahmad, M; Chinn, G; Xing, L [Stanford University, Stanford, CA (United States)

    2016-06-15

    Purpose: The application of Compton cameras (CC) is a novel approach translating XFCT to a practical modality realized with clinical CT systems without the restriction of pencil beams. The dual modality design offers additional information without extra patient dose. The purpose of this work is to investigate the feasibility and efficacy of using CCs for volumetric x-ray fluorescence (XF) imaging by Monte Carlo (MC) simulations and statistical image reconstruction. Methods: The feasibility of a CC for imaging x-ray fluorescence emitted from targeted lesions is examined by MC simulations. 3 mm diameter water spheres with various gold concentrations and detector distances are placed inside the lung of an adult human phantom (MIRD) and are irradiated with both fan and cone-beam geometries. A sandwich design CC composed of Silicon and CdTe is used to image the gold nanoparticle distribution. The detection system comprises four 16×26 cm{sup 2} detector panels placed on the chest of a MIRD phantom. Constraints of energy-, spatial-resolution, clinical geometries and Doppler broadening are taken into account. Image reconstruction is performed with a list-mode MLEM algorithm with cone-projector on a GPU. Results: The comparison of reconstruction of cone- and fan-beam excitation shows that the spatial resolution is improved by 23% for fan-beams with significantly decreased processing time. Cone-beam excitation increases scatter content disturbing quantification of lesions near the body surface. Spatial resolution and detectability limit in the center of the lung is 8.7 mm and 20 fM for 50 nm diameter gold nanoparticles at 20 mGy. Conclusion: The implementation of XFCT with a CC is a feasible method for molecular imaging with high atomic number probes. Given constrains of detector resolutions, Doppler broadening, and limited exposure dose, spatial resolutions comparable with PET and molecular sensitivities in the fM range are realizable with current detector technology.

  10. Development of an integrated response generator for Si/CdTe semiconductor Compton cameras

    International Nuclear Information System (INIS)

    Odaka, Hirokazu; Sugimoto, Soichiro; Ishikawa, Shin-nosuke; Katsuta, Junichiro; Koseki, Yuu; Fukuyama, Taro; Saito, Shinya; Sato, Rie; Sato, Goro; Watanabe, Shin

    2010-01-01

    We have developed an integrated response generator based on Monte Carlo simulation for Compton cameras composed of silicon (Si) and cadmium telluride (CdTe) semiconductor detectors. In order to construct an accurate detector response function, the simulation is required to include a comprehensive treatment of the semiconductor detector devices and the data processing system in addition to simulating particle tracking. Although CdTe is an excellent semiconductor material for detection of soft gamma rays, its ineffective charge transport property distorts its spectral response. We investigated the response of CdTe pad detectors in the simulation and present our initial results here. We also performed the full simulation of prototypes of Si/CdTe semiconductor Compton cameras and report on the reproducibility of detection efficiencies and angular resolutions of the cameras, both of which are essential performance parameters of astrophysical instruments.

  11. INDIA: Photon multiplicity detector

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    25 mm square and are assembled in 26 light-tight box modules. Each fibre matrix of 38 rows and 50 columns is read out using an image intensifier and CCD camera system. At present the PMD uses 26 readout cameras from the old UA2 experiment, including 20 units on loan from CERN. The detector covers an area of 21 square metres in the forward region. Its total weight with the stand and lead converter plates is about 6 tons. A central hole about 1 metre square avoids problems with overlapping showers. The detector took its first data during the lead ion run late last year (December 1994, page 15)

  12. INDIA: Photon multiplicity detector

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-01-15

    square and are assembled in 26 light-tight box modules. Each fibre matrix of 38 rows and 50 columns is read out using an image intensifier and CCD camera system. At present the PMD uses 26 readout cameras from the old UA2 experiment, including 20 units on loan from CERN. The detector covers an area of 21 square metres in the forward region. Its total weight with the stand and lead converter plates is about 6 tons. A central hole about 1 metre square avoids problems with overlapping showers. The detector took its first data during the lead ion run late last year (December 1994, page 15)

  13. Video Chat with Multiple Cameras

    OpenAIRE

    MacCormick, John

    2012-01-01

    The dominant paradigm for video chat employs a single camera at each end of the conversation, but some conversations can be greatly enhanced by using multiple cameras at one or both ends. This paper provides the first rigorous investigation of multi-camera video chat, concentrating especially on the ability of users to switch between views at either end of the conversation. A user study of 23 individuals analyzes the advantages and disadvantages of permitting a user to switch between views at...

  14. Transmission electron microscope CCD camera

    Science.gov (United States)

    Downing, Kenneth H.

    1999-01-01

    In order to improve the performance of a CCD camera on a high voltage electron microscope, an electron decelerator is inserted between the microscope column and the CCD. This arrangement optimizes the interaction of the electron beam with the scintillator of the CCD camera while retaining optimization of the microscope optics and of the interaction of the beam with the specimen. Changing the electron beam energy between the specimen and camera allows both to be optimized.

  15. A Motionless Camera

    Science.gov (United States)

    1994-01-01

    Omniview, a motionless, noiseless, exceptionally versatile camera was developed for NASA as a receiving device for guiding space robots. The system can see in one direction and provide as many as four views simultaneously. Developed by Omniview, Inc. (formerly TRI) under a NASA Small Business Innovation Research (SBIR) grant, the system's image transformation electronics produce a real-time image from anywhere within a hemispherical field. Lens distortion is removed, and a corrected "flat" view appears on a monitor. Key elements are a high resolution charge coupled device (CCD), image correction circuitry and a microcomputer for image processing. The system can be adapted to existing installations. Applications include security and surveillance, teleconferencing, imaging, virtual reality, broadcast video and military operations. Omniview technology is now called IPIX. The company was founded in 1986 as TeleRobotics International, became Omniview in 1995, and changed its name to Interactive Pictures Corporation in 1997.

  16. The Circular Camera Movement

    DEFF Research Database (Denmark)

    Hansen, Lennard Højbjerg

    2014-01-01

    It has been an accepted precept in film theory that specific stylistic features do not express specific content. Nevertheless, it is possible to find many examples in the history of film in which stylistic features do express specific content: for instance, the circular camera movement is used...... repeatedly to convey the feeling of a man and a woman falling in love. This raises the question of why producers and directors choose certain stylistic features to narrate certain categories of content. Through the analysis of several short film and TV clips, this article explores whether...... or not there are perceptual aspects related to specific stylistic features that enable them to be used for delimited narrational purposes. The article further attempts to reopen this particular stylistic debate by exploring the embodied aspects of visual perception in relation to specific stylistic features...

  17. Automatic locking radioisotope camera lock

    International Nuclear Information System (INIS)

    Rosauer, P.J.

    1978-01-01

    The lock of the present invention secures the isotope source in a stored shielded condition in the camera until a positive effort has been made to open the lock and take the source outside of the camera and prevents disconnection of the source pigtail unless the source is locked in a shielded condition in the camera. It also gives a visual indication of the locked or possible exposed condition of the isotope source and prevents the source pigtail from being completely pushed out of the camera, even when the lock is released. (author)

  18. The MARS Photon Processing Cameras for Spectral CT

    CERN Document Server

    Doesburg, Robert Michael Nicholas; Butler, APH; Renaud, PF

    This thesis is about the development of the MARS camera: a stan- dalone portable digital x-ray camera with spectral sensitivity. It is built for use in the MARS Spectral system from the Medipix2 and Medipix3 imaging chips. Photon counting detectors and Spectral CT are introduced, and Medipix is identified as a powerful new imaging device. The goals and strategy for the MARS camera are discussed. The Medipix chip physical, electronic and functional aspects, and ex- perience gained, are described. The camera hardware, firmware and supporting PC software are presented. Reports of experimental work on the process of equalisation from noise, and of tests of charge sum- ming mode, conclude the main body of the thesis. The camera has been actively used since late 2009 in pre-clinical re- search. A list of publications that derive from the use of the camera and the MARS Spectral scanner demonstrates the practical benefits already obtained from this work. Two of the publications are first- author, eight are co-authore...

  19. Low-cost uncooled VOx infrared camera development

    Science.gov (United States)

    Li, Chuan; Han, C. J.; Skidmore, George D.; Cook, Grady; Kubala, Kenny; Bates, Robert; Temple, Dorota; Lannon, John; Hilton, Allan; Glukh, Konstantin; Hardy, Busbee

    2013-06-01

    The DRS Tamarisk® 320 camera, introduced in 2011, is a low cost commercial camera based on the 17 µm pixel pitch 320×240 VOx microbolometer technology. A higher resolution 17 µm pixel pitch 640×480 Tamarisk®640 has also been developed and is now in production serving the commercial markets. Recently, under the DARPA sponsored Low Cost Thermal Imager-Manufacturing (LCTI-M) program and internal project, DRS is leading a team of industrial experts from FiveFocal, RTI International and MEMSCAP to develop a small form factor uncooled infrared camera for the military and commercial markets. The objective of the DARPA LCTI-M program is to develop a low SWaP camera (costs less than US $500 based on a 10,000 units per month production rate. To meet this challenge, DRS is developing several innovative technologies including a small pixel pitch 640×512 VOx uncooled detector, an advanced digital ROIC and low power miniature camera electronics. In addition, DRS and its partners are developing innovative manufacturing processes to reduce production cycle time and costs including wafer scale optic and vacuum packaging manufacturing and a 3-dimensional integrated camera assembly. This paper provides an overview of the DRS Tamarisk® project and LCTI-M related uncooled technology development activities. Highlights of recent progress and challenges will also be discussed. It should be noted that BAE Systems and Raytheon Vision Systems are also participants of the DARPA LCTI-M program.

  20. Underwater television camera for monitoring inner side of pressure vessel

    International Nuclear Information System (INIS)

    Takayama, Kazuhiko.

    1997-01-01

    An underwater television support device equipped with a rotatable and vertically movable underwater television camera and an underwater television camera controlling device for monitoring images of the inside of the reactor core photographed by the underwater television camera to control the position of the underwater television camera and the underwater light are disposed on an upper lattice plate of a reactor pressure vessel. Both of them are electrically connected with each other by way of a cable to rapidly observe the inside of the reactor core by the underwater television camera. The reproducibility is extremely satisfactory by efficiently concentrating the position of the camera and image information upon inspection and observation. As a result, the steps for periodical inspection can be reduced to shorten the days for the periodical inspection. Since there is no requirement to withdraw fuel assemblies over a wide reactor core region, and the device can be used with the fuel assemblies being left as they are in the reactor, it is suitable for inspection of detectors for nuclear instrumentation. (N.H.)

  1. The Philosophy and Feasibility of Dual Readout Calorimetry

    International Nuclear Information System (INIS)

    Hauptman, John

    2006-01-01

    I will discuss the general physical ideas behind dual-readout calorimetry, their implementation in DREAM (Dual REAdout Module) with exact separation of scintillation and Cerenkov light, implementation with mixed light in DREAM fibers, anticipated implementation in PbWO4 crystals with applications to the 4th Concept detector and to CMS, use in high energy gamma-ray and cosmic ray astrophysics with Cerenkov and N2 fluorescent light, and implementation in the 4th Concept detector for muon identification

  2. QCD Dual

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2009-01-01

    We uncover a novel solution of the 't Hooft anomaly matching conditions for QCD. Interestingly in the perturbative regime the new gauge theory, if interpreted as a possible QCD dual, predicts the critical number of flavors above which QCD in the nonperturbative regime, develops an infrared stable...

  3. Small animals bone density and morphometry analysis with a dual energy X-rays absorptiometry bone densitometer using a 2D digital radiographic detector; Analyse de la densite osseuse et de la morphometrie de petits animaux avec un osteodensitometre bi-energie utilisant un capteur 2D de radiographie numerique

    Energy Technology Data Exchange (ETDEWEB)

    Boudousq, V. [Centre Hospitalier Universitaire de Nimes, 30 (France); Bordy, T.; Gonon, G.; Dinten, J.M. [CEA Grenoble (DTBS/STD), Lab. d' Electronique et de Technologie de l' Informatique, LETI, 38 (France)

    2004-07-01

    LEXXOS (DMS, Montpellier, France) is the first axial and total body cone beam bone densitometer using a 2D digital radiographic detector. In previous papers, technical principles and patients' Bone Mineral Density (BMD) measurement performances were presented. Bone densitometers are also used on small animals for drug development. In this presentation, we show how LEXXOS can be adapted for small animals' examinations and evaluate its performances. At first, in order to take advantage of the whole area of the 20 x 20 cm{sup 2} digital radiographic detector, it has been made profit of X-Rays magnification by adapting the geometrical configuration. Secondly, as small animals present low BMD, a specific dual energy calibration has been defined. This adapted system has then been evaluated on two sets of mice: six reference mice and six ovariectomized mice. Each month, these two populations have been examined and the averaged total body BMD has been measured. This evaluation shows that the right order of BMD magnitude is obtained and, as expected, BMD increases on two sets until a period around puberty and the ovariectomized set presents a significant decrease after. Moreover, the bone image obtained by dual energy processing on LEXXOS presents a radiographic image quality providing useful complementary information on bone morphometry and architecture. This study shows that LEXXOS cone beam bone densitometer provides simultaneously useful quantitative and qualitative information for analysis of bone evolution on small animals. In the future, same system architecture and processing methodology can be used with higher resolution detectors in order to refine information on bone architecture. (authors)

  4. Gamma camera based FDG PET in oncology

    International Nuclear Information System (INIS)

    Park, C. H.

    2002-01-01

    Positron Emission Tomography(PET) was introduced as a research tool in the 1970s and it took about 20 years before PET became an useful clinical imaging modality. In the USA, insurance coverage for PET procedures in the 1990s was the turning point, I believe, for this progress. Initially PET was used in neurology but recently more than 80% of PET procedures are in oncological applications. I firmly believe, in the 21st century, one can not manage cancer patients properly without PET and PET is very important medical imaging modality in basic and clinical sciences. PET is grouped into 2 categories; conventional (c) and gamma camera based ( CB ) PET. CB PET is more readily available utilizing dual-head gamma cameras and commercially available FDG to many medical centers at low cost to patients. In fact there are more CB PET in operation than cPET in the USA. CB PET is inferior to cPET in its performance but clinical studies in oncology is feasible without expensive infrastructures such as staffing, rooms and equipments. At Ajou university Hospital, CBPET was installed in late 1997 for the first time in Korea as well as in Asia and the system has been used successfully and effectively in oncological applications. Our was the fourth PET operation in Korea and I believe this may have been instrumental for other institutions got interested in clinical PET. The following is a brief description of our clinical experience of FDG CBPET in oncology

  5. A Compton camera prototype for prompt gamma medical imaging

    Directory of Open Access Journals (Sweden)

    Thirolf P.G.

    2016-01-01

    Full Text Available Compton camera prototype for a position-sensitive detection of prompt γ rays from proton-induced nuclear reactions is being developed in Garching. The detector system allows to track the Comptonscattered electrons. The camera consists of a monolithic LaBr3:Ce scintillation absorber crystal, read out by a multi-anode PMT, preceded by a stacked array of 6 double-sided silicon strip detectors acting as scatterers. The LaBr3:Ce crystal has been characterized with radioactive sources. Online commissioning measurements were performed with a pulsed deuteron beam at the Garching Tandem accelerator and with a clinical proton beam at the OncoRay facility in Dresden. The determination of the interaction point of the photons in the monolithic crystal was investigated.

  6. (99m)Tc-MDP bone scintigraphy of the hand: comparing the use of novel cadmium zinc telluride (CZT) and routine NaI(Tl) detectors.

    Science.gov (United States)

    Koulikov, Victoria; Lerman, Hedva; Kesler, Mikhail; Even-Sapir, Einat

    2015-12-01

    Cadmium zinc telluride (CZT) solid-state detectors have been recently introduced in the field of nuclear medicine in cardiology and breast imaging. The aim of the current study was to evaluate the performance of the novel detectors (CZT) compared to that of the routine NaI(Tl) in bone scintigraphy. A dual-headed CZT-based camera dedicated originally to breast imaging has been used, and in view of the limited size of the detectors, the hands were chosen as the organ for assessment. This is a clinical study. Fifty-eight consecutive patients (total 116 hands) referred for bone scan for suspected hand pathology gave their informed consent to have two acquisitions, using the routine camera and the CZT-based camera. The latter was divided into full-dose full-acquisition time (FD CZT) and reduced-dose short-acquisition time (RD CZT) on CZT technology, so three image sets were available for analysis. Data analysis included comparing the detection of hot lesions and identification of the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints. A total of 69 hot lesions were detected on the CZT image sets; of these, 61 were identified as focal sites of uptake on NaI(Tl) data. On FD CZT data, 385 joints were identified compared to 168 on NaI(Tl) data (p < 0.001). There was no statistically significant difference in delineation of joints between FD and RD CZT data as the latter identified 383 joints. Bone scintigraphy using a CZT-based gamma camera is associated with improved lesion detection and anatomic definition. The superior physical characteristics of this technique raised a potential reduction in administered dose and/or acquisition time without compromising image quality.

  7. Automatic control of movable detectors

    International Nuclear Information System (INIS)

    Wassel, W.W.; Remley, G.W.

    1980-01-01

    An invention is described, relating to a microprocessor based control system for a plurality of movable detectors, e.g. a nuclear reactor flux mapping system, with new system architecture which increases system availability by preventing faults on any of the detection channels from disabling the remaining channels. The system has, say, four drive trains for a number of detectors. Functional separation is realized by having two channels control their associated two drive trains. Redundancy is provided by having dual channels for operator interface. Communications between the functionally separate channels is accomplished by employing two-ported memories in conjunction with multiple microprocessors. (author)

  8. Multi-Angle Snowflake Camera Value-Added Product

    Energy Technology Data Exchange (ETDEWEB)

    Shkurko, Konstantin [Univ. of Utah, Salt Lake City, UT (United States); Garrett, T. [Univ. of Utah, Salt Lake City, UT (United States); Gaustad, K [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-12-01

    The Multi-Angle Snowflake Camera (MASC) addresses a need for high-resolution multi-angle imaging of hydrometeors in freefall with simultaneous measurement of fallspeed. As illustrated in Figure 1, the MASC consists of three cameras, separated by 36°, each pointing at an identical focal point approximately 10 cm away. Located immediately above each camera, a light aims directly at the center of depth of field for its corresponding camera. The focal point at which the cameras are aimed lies within a ring through which hydrometeors fall. The ring houses a system of near-infrared emitter-detector pairs, arranged in two arrays separated vertically by 32 mm. When hydrometeors pass through the lower array, they simultaneously trigger all cameras and lights. Fallspeed is calculated from the time it takes to traverse the distance between the upper and lower triggering arrays. The trigger electronics filter out ambient light fluctuations associated with varying sunlight and shadows. The microprocessor onboard the MASC controls the camera system and communicates with the personal computer (PC). The image data is sent via FireWire 800 line, and fallspeed (and camera control) is sent via a Universal Serial Bus (USB) line that relies on RS232-over-USB serial conversion. See Table 1 for specific details on the MASC located at the Oliktok Point Mobile Facility on the North Slope of Alaska. The value-added product (VAP) detailed in this documentation analyzes the raw data (Section 2.0) using Python: images rely on OpenCV image processing library and derived aggregated statistics rely on some clever averaging. See Sections 4.1 and 4.2 for more details on what variables are computed.

  9. NUKAB system use with the PICKER DYNA CAMERA II

    International Nuclear Information System (INIS)

    Collet, H.; Faurous, P.; Lehn, A.; Suquet, P.

    Present-day data processing units connected to scintillation gamma cameras can make use of cabled programme or recorded programme systems. The NUKAB system calls on the latter technique. The central element of the data processing unit, connected to the PICKER DYNA CAMERA II output, consists of a DIGITAL PDP 8E computer with 12-bit technological words. The use of a 12-bit technological format restricts the possibilities of digitalisation, 64x64 images representing the practical limit. However the NUKAB system appears well suited to the processing of data from gamma cameras at present in service. The addition of output terminals of the tracing panel type should widen the possibilities of the system. It seems that the 64x64 format is not a handicap in view of the resolution power of the detectors [fr

  10. The "All Sky Camera Network"

    Science.gov (United States)

    Caldwell, Andy

    2005-01-01

    In 2001, the "All Sky Camera Network" came to life as an outreach program to connect the Denver Museum of Nature and Science (DMNS) exhibit "Space Odyssey" with Colorado schools. The network is comprised of cameras placed strategically at schools throughout Colorado to capture fireballs--rare events that produce meteorites.…

  11. The Eye of the Camera

    NARCIS (Netherlands)

    van Rompay, Thomas Johannes Lucas; Vonk, Dorette J.; Fransen, M.L.

    2009-01-01

    This study addresses the effects of security cameras on prosocial behavior. Results from previous studies indicate that the presence of others can trigger helping behavior, arising from the need for approval of others. Extending these findings, the authors propose that security cameras can likewise

  12. On camera-based smoke and gas leakage detection

    Energy Technology Data Exchange (ETDEWEB)

    Nyboe, Hans Olav

    1999-07-01

    Gas detectors are found in almost every part of industry and in many homes as well. An offshore oil or gas platform may host several hundred gas detectors. The ability of the common point and open path gas detectors to detect leakages depends on their location relative to the location of a gas cloud. This thesis describes the development of a passive volume gas detector, that is, one than will detect a leakage anywhere in the area monitored. After the consideration of several detection techniques it was decided to use an ordinary monochrome camera as sensor. Because a gas leakage may perturb the index of refraction, parts of the background appear to be displaced from their true positions, and it is necessary to develop algorithms that can deal with small differences between images. The thesis develops two such algorithms. Many image regions can be defined and several feature values can be computed for each region. The value of the features depends on the pattern in the image regions. The classes studied in this work are: reference, gas, smoke and human activity. Test show that observation belonging to these classes can be classified fairly high accuracy. The features in the feature set were chosen and developed for this particular application. Basically, the features measure the magnitude of pixel differences, size of detected phenomena and image distortion. Interesting results from many experiments are presented. Most important, the experiments show that apparent motion caused by a gas leakage or heat convection can be detected by means of a monochrome camera. Small leakages of methane can be detected at a range of about four metres. Other gases, such as butane, where the densities differ more from the density of air than the density of methane does, can be detected further from the camera. Gas leakages large enough to cause condensation have been detected at a camera distance of 20 metres. 59 refs., 42 figs., 13 tabs.

  13. Performance of an Uncooled Camera Utilizing an SWIR InGaAs 256x256 FPA for Imaging in the 1.0 micrometer - 1.7 micrometer Spectral Band

    National Research Council Canada - National Science Library

    Barton, J

    1998-01-01

    .... The camera spectral sensitivity is established by the material properties of the detector array which is composed of photovoltaic detectors formed in an epitaxial layer of InGaAs with a composition...

  14. Dual modality densitometry

    International Nuclear Information System (INIS)

    Tjugum, Stein-Arild

    2003-01-01

    Different measurement principles and design issues for gamma-ray densitometry for pipe flow are investigated. The dual modality densitometry (DMD) principle for salinity measurement and flow regime identification by multibeam densitometry are tested and verified. The measurement principles are implemented in a compact instrument design with low energy source and compact detectors. The DMD principle is experimentally verified for 3 inch and 2 inch pipes. These measurements are done on homogenous brine/gas mixtures. Both salinity independent GVF measurements and salinity measurements are obtained. The standard deviation of the salinity measurements are about 2 percent. This measurement inaccuracy is mainly caused by inhomogeneity in the liquid/gas distribution, and measurements are thus sensitive to changes in the flow regime. Models for the generation of scattered radiation are developed, and these have been used in the data-analysis and for producing special sensitivity maps for the generation of scattered radiation. The models are a useful tool for further development of the DMD principle. The work on multibeam gamma-ray densitometry has shown that flow regimes can be identified with as few as two detectors. This is verified in the flow-loop tests. Unambiguous flow regime identification will often require that the multibeam measurements are combined with other flow measurements. With a higher number of detectors more detailed information is found, and from the 9-beam measurements with the University of Bergen (UoB) gamma-ray tomography different flow regimes could clearly be identified from time series plots of the data. A laboratory prototype compact gamma-ray densitometer, the MiniGamma, has been built up and tested. Both the DMD measurement principle and the multibeam arrangement for flow regime identification are implemented in the instrument, and are successfully tested. The detector-types tested are CdZnTe semiconductor detectors, a miniature scintillation

  15. OPERA goes on camera

    CERN Multimedia

    2007-01-01

    OPERA, the experiment which uses the neutrino beam of CERN’s CNGS facility, has delivered its first neutrino "photos". The core of the detector has been commissioned and has produced images of events resulting from neutrino collisions. The reconstruction of the core (a few cubic millimetres!) of a neutrino interaction at OPERA. The neutrino arriving from the left of the image has interacted with the lead of a brick, producing various particles identifiable by their tracks visible in the emulsion.The snapshot is tiny but it was greeted with enthusiasm by the physicists of OPERA. On 2 October, for the first time, the experiment at the Gran Sasso Laboratory in Italy "photographed" an event produced by the beam of neutrinos sent from CERN, 732 kilometres away. One of the 60,000 photosensitive bricks already installed at the heart of the experiment had produced its first particle track. The commissioning of the OPERA experiment began la...

  16. Collimated trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    1980-01-01

    The principal problem in trans-axial tomographic radioisotope scanning is the length of time required to obtain meaningful data. Patient movement and radioisotope migration during the scanning period can cause distortion of the image. The object of this invention is to reduce the scanning time without degrading the images obtained. A system is described in which a scintillation camera detector is moved to an orbit about the cranial-caudal axis relative to the patient. A collimator is used in which lead septa are arranged so as to admit gamma rays travelling perpendicular to this axis with high spatial resolution and those travelling in the direction of the axis with low spatial resolution, thus increasing the rate of acceptance of radioactive events to contribute to the positional information obtainable without sacrificing spatial resolution. (author)

  17. Applications of iQID cameras

    Science.gov (United States)

    Han, Ling; Miller, Brian W.; Barrett, Harrison H.; Barber, H. Bradford; Furenlid, Lars R.

    2017-09-01

    iQID is an intensified quantum imaging detector developed in the Center for Gamma-Ray Imaging (CGRI). Originally called BazookaSPECT, iQID was designed for high-resolution gamma-ray imaging and preclinical gamma-ray single-photon emission computed tomography (SPECT). With the use of a columnar scintillator, an image intensifier and modern CCD/CMOS sensors, iQID cameras features outstanding intrinsic spatial resolution. In recent years, many advances have been achieved that greatly boost the performance of iQID, broadening its applications to cover nuclear and particle imaging for preclinical, clinical and homeland security settings. This paper presents an overview of the recent advances of iQID technology and its applications in preclinical and clinical scintigraphy, preclinical SPECT, particle imaging (alpha, neutron, beta, and fission fragment), and digital autoradiography.

  18. Dual Entwining Structures and Dual Entwined Modules

    OpenAIRE

    Abuhlail, Jawad Y.

    2003-01-01

    In this note we introduce and investigate the concepts of dual entwining structures and dual entwined modules. This generalizes the concepts of dual Doi-Koppinen structures and dual Doi-Koppinen modules introduced (in the infinite case over rings) by the author is his dissertation.

  19. Optical Characterization of the SPT-3G Camera

    Science.gov (United States)

    Pan, Z.; Ade, P. A. R.; Ahmed, Z.; Anderson, A. J.; Austermann, J. E.; Avva, J. S.; Thakur, R. Basu; Bender, A. N.; Benson, B. A.; Carlstrom, J. E.; Carter, F. W.; Cecil, T.; Chang, C. L.; Cliche, J. F.; Cukierman, A.; Denison, E. V.; de Haan, T.; Ding, J.; Dobbs, M. A.; Dutcher, D.; Everett, W.; Foster, A.; Gannon, R. N.; Gilbert, A.; Groh, J. C.; Halverson, N. W.; Harke-Hosemann, A. H.; Harrington, N. L.; Henning, J. W.; Hilton, G. C.; Holzapfel, W. L.; Huang, N.; Irwin, K. D.; Jeong, O. B.; Jonas, M.; Khaire, T.; Kofman, A. M.; Korman, M.; Kubik, D.; Kuhlmann, S.; Kuo, C. L.; Lee, A. T.; Lowitz, A. E.; Meyer, S. S.; Michalik, D.; Montgomery, J.; Nadolski, A.; Natoli, T.; Nguyen, H.; Noble, G. I.; Novosad, V.; Padin, S.; Pearson, J.; Posada, C. M.; Rahlin, A.; Ruhl, J. E.; Saunders, L. J.; Sayre, J. T.; Shirley, I.; Shirokoff, E.; Smecher, G.; Sobrin, J. A.; Stark, A. A.; Story, K. T.; Suzuki, A.; Tang, Q. Y.; Thompson, K. L.; Tucker, C.; Vale, L. R.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Yoon, K. W.; Young, M. R.

    2018-05-01

    The third-generation South Pole Telescope camera is designed to measure the cosmic microwave background across three frequency bands (centered at 95, 150 and 220 GHz) with ˜ 16,000 transition-edge sensor (TES) bolometers. Each multichroic array element on a detector wafer has a broadband sinuous antenna that couples power to six TESs, one for each of the three observing bands and both polarizations, via lumped element filters. Ten detector wafers populate the detector array, which is coupled to the sky via a large-aperture optical system. Here we present the frequency band characterization with Fourier transform spectroscopy, measurements of optical time constants, beam properties, and optical and polarization efficiencies of the detector array. The detectors have frequency bands consistent with our simulations and have high average optical efficiency which is 86, 77 and 66% for the 95, 150 and 220 GHz detectors. The time constants of the detectors are mostly between 0.5 and 5 ms. The beam is round with the correct size, and the polarization efficiency is more than 90% for most of the bolometers.

  20. Performance characteristics of the novel PETRRA positron camera

    CERN Document Server

    Ott, R J; Erlandsson, K; Reader, A; Duxbury, D; Bateman, J; Stephenson, R; Spill, E

    2002-01-01

    The PETRRA positron camera consists of two 60 cmx40 cm annihilation photon detectors mounted on a rotating gantry. Each detector contains large BaF sub 2 scintillators interfaced to large area multiwire proportional chambers filled with a photo-sensitive vapour (tetrakis-(dimethylamino)-ethylene). The spatial resolution of the camera has been measured as 6.5+-1.0 mm FWHM throughout the sensitive field-of-view (FoV), the timing resolution is between 7 and 10 ns FWHM and the detection efficiency for annihilation photons is approx 30% per detector. The count-rates obtained, from a 20 cm diameter by 11 cm long water filled phantom containing 90 MBq of sup 1 sup 8 F, were approx 1.25x10 sup 6 singles and approx 1.1x10 sup 5 cps raw coincidences, limited only by the read-out system dead-time of approx 4 mu s. The count-rate performance, sensitivity and large FoV make the camera ideal for whole-body imaging in oncology.

  1. [Dual pathology].

    Science.gov (United States)

    Rougier, A

    2008-05-01

    Dual pathology is defined as the association of two potentially epileptogenic lesions, hippocampal (sclerosis, neuronal loss) and extrahippocampal (temporal or extratemporal). Epileptic activity may be generated by either lesion and the relative importance of every lesion's epileptogenicity conditions the surgical strategy adopted. Most frequently associated with hippocampal sclerosis are cortical dysplasias. The common physiopathology of the two lesions is not clearly established. Extrahippocampal lesions may be undetectable on MRI (microdysgenesis, for example) and ictal discharge patterns may vary among dual pathology patients. The surgical strategy depends on the location of the extrahippocampal lesion and its relative role in seizure generation; however, reported surgical results suggest that simultaneous resection of mesial temporal structures along with the extrahippocampal lesion should be performed.

  2. Measurement of the timing behaviour of off-the-shelf cameras

    Science.gov (United States)

    Schatz, Volker

    2017-04-01

    This paper presents a measurement method suitable for investigating the timing properties of cameras. A single light source illuminates the camera detector starting with a varying defined delay after the camera trigger. Pixels from the recorded camera frames are summed up and normalised, and the resulting function is indicative of the overlap between illumination and exposure. This allows one to infer the trigger delay and the exposure time with sub-microsecond accuracy. The method is therefore of interest when off-the-shelf cameras are used in reactive systems or synchronised with other cameras. It can supplement radiometric and geometric calibration methods for cameras in scientific use. A closer look at the measurement results reveals deviations from the ideal camera behaviour of constant sensitivity limited to the exposure interval. One of the industrial cameras investigated retains a small sensitivity long after the end of the nominal exposure interval. All three investigated cameras show non-linear variations of sensitivity at O≤ft({{10}-3}\\right) to O≤ft({{10}-2}\\right) during exposure. Due to its sign, the latter effect cannot be described by a sensitivity function depending on the time after triggering, but represents non-linear pixel characteristics.

  3. Chemochromic Hydrogen Leak Detectors

    Science.gov (United States)

    Roberson, Luke; Captain, Janine; Williams, Martha; Smith, Trent; Tate, LaNetra; Raissi, Ali; Mohajeri, Nahid; Muradov, Nazim; Bokerman, Gary

    2009-01-01

    At NASA, hydrogen safety is a key concern for space shuttle processing. Leaks of any level must be quickly recognized and addressed due to hydrogen s lower explosion limit. Chemo - chromic devices have been developed to detect hydrogen gas in several embodiments. Because hydrogen is odorless and colorless and poses an explosion hazard, there is an emerging need for sensors to quickly and accurately detect low levels of leaking hydrogen in fuel cells and other advanced energy- generating systems in which hydrogen is used as fuel. The device incorporates a chemo - chromic pigment into a base polymer. The article can reversibly or irreversibly change color upon exposure to hydrogen. The irreversible pigment changes color from a light beige to a dark gray. The sensitivity of the pigment can be tailored to its application by altering its exposure to gas through the incorporation of one or more additives or polymer matrix. Furthermore, through the incorporation of insulating additives, the chemochromic sensor can operate at cryogenic temperatures as low as 78 K. A chemochromic detector of this type can be manufactured into any feasible polymer part including injection molded plastic parts, fiber-spun textiles, or extruded tapes. The detectors are simple, inexpensive, portable, and do not require an external power source. The chemochromic detectors were installed and removed easily at the KSC launch pad without need for special expertise. These detectors may require an external monitor such as the human eye, camera, or electronic detector; however, they could be left in place, unmonitored, and examined later for color change to determine whether there had been exposure to hydrogen. In one type of envisioned application, chemochromic detectors would be fabricated as outer layers (e.g., casings or coatings) on high-pressure hydrogen storage tanks and other components of hydrogen-handling systems to provide visible indications of hydrogen leaks caused by fatigue failures or

  4. Cryogenic detectors

    International Nuclear Information System (INIS)

    Zehnder, A.

    1987-01-01

    Presently the development of new large scale detector systems, used in very high energy physics experiments, is very active. In the low energy range, the introduction of charge coupled devices allows improved spacial and energy resolution. In the keV region, high resolution can only be achieved via the well established diffraction spectrometers with the well-known disadvantage of a small throughput. There exist no efficient detectors for non-ionizing radiation such as coherent nuclear scattering of weakly interacting particles. The development of high resolution solid state detectors in the keV-region with the possibility of nuclear recoil detection is therefore highly desired. Such detectors applied in astro and particle physics would thus allow one to obtain new information not achievable otherwise. Three types of cryogenic detectors exist: Calorimeters/Bolometers. This type is sensitive to the produced excess phonons and measures the deposited energy by detecting the heat pulses. Excess charge carriers should be used to produce phonons. Tunneling junctions. This type is sensitive to excess charge produced by the Cooper pair breakup. Excess phonons should be used to break up Cooper pairs. Superheated superconducting granules (SSG). An SSG detector consists of granules, the metastability of which is disturbed by radiation. The Meissner effect then causes a change in the field distribution of the applied external field, which can be detected. The present paper discusses the basic principle of calorimetric and tunneling junction detectors and some of their applications. 26 refs., 7 figs., 1 tab

  5. Detectors - Electronics

    International Nuclear Information System (INIS)

    Bregeault, J.; Gabriel, J.L.; Hierle, G.; Lebotlan, P.; Leconte, A.; Lelandais, J.; Mosrin, P.; Munsch, P.; Saur, H.; Tillier, J.

    1998-01-01

    The reports presents the main results obtained in the fields of radiation detectors and associated electronics. In the domain of X-ray gas detectors for the keV range efforts were undertaken to rise the detector efficiency. Multiple gap parallel plate chambers of different types as well as different types of X → e - converters were tested to improve the efficiency (values of 2.4% at 60 KeV were reached). In the field of scintillators a study of new crystals has been carried out (among which Lutetium orthosilicate). CdTe diode strips for obtaining X-ray imaging were studied. The complete study of a linear array of 8 CdTe pixels has been performed and certified. The results are encouraging and point to this method as a satisfying solution. Also, a large dimension programmable chamber was used to study the influence of temperature on the inorganic scintillators in an interval from -40 deg. C to +150 deg. C. Temperature effects on other detectors and electronic circuits were also investigated. In the report mentioned is also the work carried out for the realization of the DEMON neutron multidetector. For neutron halo experiments different large area Si detectors associated with solid and gas position detectors were realized. In the frame of a contract with COGEMA a systematic study of Li doped glasses was undertaken aiming at replacing with a neutron probe the 3 He counters presently utilized in pollution monitoring. An industrial prototype has been realised. Other studies were related to integrated analog chains, materials for Cherenkov detectors, scintillation probes for experiments on fundamental processes, gas position sensitive detectors, etc. In the field of associated electronics there are mentioned the works related to the multidetector INDRA, data acquisition, software gamma spectrometry, automatic gas pressure regulation in detectors, etc

  6. Development of underwater camera using high-definition camera

    International Nuclear Information System (INIS)

    Tsuji, Kenji; Watanabe, Masato; Takashima, Masanobu; Kawamura, Shingo; Tanaka, Hiroyuki

    2012-01-01

    In order to reduce the time for core verification or visual inspection of BWR fuels, the underwater camera using a High-Definition camera has been developed. As a result of this development, the underwater camera has 2 lights and 370 x 400 x 328mm dimensions and 20.5kg weight. Using the camera, 6 or so spent-fuel IDs are identified at 1 or 1.5m distance at a time, and 0.3mmφ pin-hole is recognized at 1.5m distance and 20 times zoom-up. Noises caused by radiation less than 15 Gy/h are not affected the images. (author)

  7. Imaging Asteroid 4 Vesta Using the Framing Camera

    Science.gov (United States)

    Keller, H. Uwe; Nathues, Andreas; Coradini, Angioletta; Jaumann, Ralf; Jorda, Laurent; Li, Jian-Yang; Mittlefehldt, David W.; Mottola, Stefano; Raymond, C. A.; Schroeder, Stefan E.

    2011-01-01

    The Framing Camera (FC) onboard the Dawn spacecraft serves a dual purpose. Next to its central role as a prime science instrument it is also used for the complex navigation of the ion drive spacecraft. The CCD detector with 1024 by 1024 pixels provides the stability for a multiyear mission and its high requirements of photometric accuracy over the wavelength band from 400 to 1000 nm covered by 7 band-pass filters. Vesta will be observed from 3 orbit stages with image scales of 227, 63, and 17 m/px, respectively. The mapping of Vesta s surface with medium resolution will be only completed during the exit phase when the north pole will be illuminated. A detailed pointing strategy will cover the surface at least twice at similar phase angles to provide stereo views for reconstruction of the topography. During approach the phase function of Vesta was determined over a range of angles not accessible from earth. This is the first step in deriving the photometric function of the surface. Combining the topography based on stereo tie points with the photometry in an iterative procedure will disclose details of the surface morphology at considerably smaller scales than the pixel scale. The 7 color filters are well positioned to provide information on the spectral slope in the visible, the depth of the strong pyroxene absorption band, and their variability over the surface. Cross calibration with the VIR spectrometer that extends into the near IR will provide detailed maps of Vesta s surface mineralogy and physical properties. Georeferencing all these observation will result in a coherent and unique data set. During Dawn s approach and capture FC has already demonstrated its performance. The strong variation observed by the Hubble Space Telescope can now be correlated with surface units and features. We will report on results obtained from images taken during survey mode covering the whole illuminated surface. Vesta is a planet-like differentiated body, but its surface

  8. Hydrogen detector

    International Nuclear Information System (INIS)

    Kumagaya, Hiromichi; Yoshida, Kazuo; Sanada, Kazuo; Chigira, Sadao.

    1994-01-01

    The present invention concerns a hydrogen detector for detecting water-sodium reaction. The hydrogen detector comprises a sensor portion having coiled optical fibers and detects hydrogen on the basis of the increase of light transmission loss upon hydrogen absorption. In the hydrogen detector, optical fibers are wound around and welded to the outer circumference of a quartz rod, as well as the thickness of the clad layer of the optical fiber is reduced by etching. With such procedures, size of the hydrogen detecting sensor portion can be decreased easily. Further, since it can be used at high temperature, diffusion rate is improved to shorten the detection time. (N.H.)

  9. Polarizing aperture stereoscopic cinema camera

    Science.gov (United States)

    Lipton, Lenny

    2012-07-01

    The art of stereoscopic cinematography has been held back because of the lack of a convenient way to reduce the stereo camera lenses' interaxial to less than the distance between the eyes. This article describes a unified stereoscopic camera and lens design that allows for varying the interaxial separation to small values using a unique electro-optical polarizing aperture design for imaging left and right perspective views onto a large single digital sensor, the size of the standard 35 mm frame, with the means to select left and right image information. Even with the added stereoscopic capability, the appearance of existing camera bodies will be unaltered.

  10. Camera Concepts for the Advanced Gamma-Ray Imaging System (AGIS)

    Science.gov (United States)

    Nepomuk Otte, Adam

    2009-05-01

    The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation observatory in ground-based very high energy gamma-ray astronomy. Design goals are ten times better sensitivity, higher angular resolution, and a lower energy threshold than existing Cherenkov telescopes. Each telescope is equipped with a camera that detects and records the Cherenkov-light flashes from air showers. The camera is comprised of a pixelated focal plane of blue sensitive and fast (nanosecond) photon detectors that detect the photon signal and convert it into an electrical one. The incorporation of trigger electronics and signal digitization into the camera are under study. Given the size of AGIS, the camera must be reliable, robust, and cost effective. We are investigating several directions that include innovative technologies such as Geiger-mode avalanche-photodiodes as a possible detector and switched capacitor arrays for the digitization.

  11. Theoretical considerations on the possibility of using a television camera in scintigraphy

    International Nuclear Information System (INIS)

    Banget Mossaz, Gaston; Cezilly, Daniel; Paccard, Michel

    1969-04-01

    After a presentation of the principles of scintigraphy for the exploration of human organs, of the three main parts of scintigraphic apparels (collimator, scintillator and detector) and of their characteristics (resolving power, sensitivity, contrast), this paper describes the properties of gamma radiations interacting with matter, their absorption and their detection, some statistical notions about gamma radiations (Poisson law), the properties of the collimator, of the scintillator (sodium iodide) and of the detector. The use of a television camera is then introduced with issues concerning the limitations of a camera tube, the electronic optics of the tube, camera tubes with brightness amplification, the case of a Vidicon tube, etc. and some considerations on the potential benefits of television cameras on resolution, contrast and sensitivity

  12. Spectroscopic gamma camera for use in high dose environments

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Yuichiro, E-mail: yuichiro.ueno.bv@hitachi.com [Research and Development Group, Hitachi, Ltd., Hitachi-shi, Ibaraki-ken 319-1221 (Japan); Takahashi, Isao; Ishitsu, Takafumi; Tadokoro, Takahiro; Okada, Koichi; Nagumo, Yasushi [Research and Development Group, Hitachi, Ltd., Hitachi-shi, Ibaraki-ken 319-1221 (Japan); Fujishima, Yasutake; Kometani, Yutaka [Hitachi Works, Hitachi-GE Nuclear Energy, Ltd., Hitachi-shi, Ibaraki-ken (Japan); Suzuki, Yasuhiko [Measuring Systems Engineering Dept., Hitachi Aloka Medical, Ltd., Ome-shi, Tokyo (Japan); Umegaki, Kikuo [Faculty of Engineering, Hokkaido University, Sapporo-shi, Hokkaido (Japan)

    2016-06-21

    We developed a pinhole gamma camera to measure distributions of radioactive material contaminants and to identify radionuclides in extraordinarily high dose regions (1000 mSv/h). The developed gamma camera is characterized by: (1) tolerance for high dose rate environments; (2) high spatial and spectral resolution for identifying unknown contaminating sources; and (3) good usability for being carried on a robot and remotely controlled. These are achieved by using a compact pixelated detector module with CdTe semiconductors, efficient shielding, and a fine resolution pinhole collimator. The gamma camera weighs less than 100 kg, and its field of view is an 8 m square in the case of a distance of 10 m and its image is divided into 256 (16×16) pixels. From the laboratory test, we found the energy resolution at the 662 keV photopeak was 2.3% FWHM, which is enough to identify the radionuclides. We found that the count rate per background dose rate was 220 cps h/mSv and the maximum count rate was 300 kcps, so the maximum dose rate of the environment where the gamma camera can be operated was calculated as 1400 mSv/h. We investigated the reactor building of Unit 1 at the Fukushima Dai-ichi Nuclear Power Plant using the gamma camera and could identify the unknown contaminating source in the dose rate environment that was as high as 659 mSv/h.

  13. Effect of scatter media on small gamma camera imaging characteristics

    International Nuclear Information System (INIS)

    Ser, H. K.; Choi, Y.; Yim, K. C.

    2001-01-01

    Effect of scatter media materials and thickness, located between radioactivity and small gamma camera, on imaging characteristics was evaluated. The small gamma camera developed for breast imaging was consisted of collimator, NaI(TI) crystal (60x60x6 mm 3 ). PSPMT (position sensitive photomultiplier tube), NIMs and personal computer. Monte Carlo simulation was performed to evaluate the system sensitivity with different scatter media thickness (0∼8 cm) and materials (air and acrylie) with parallel hole collimator and diverging collimator. The sensitivity and spatial resolution was measured using the small gamma camera with the same condition applied to the simulation. Counts was decreased by 10% (air) and 54% (acrylic) with the parallel hole collimator and by 35% (air) and 63% (acrylic) with the diverging collimator. Spatial resolution was decreased as increasing the thickness of scatter media. This study substantiate the importance of a gamma camera positioning and the minimization of the distance between detector and target lesion in the clinical application of a gamma camera

  14. DUMAND detector

    CERN Multimedia

    This object is one of the 256 other detectors of the DUMAND (Deep Underwater Muon And Neutrino Detection) experiment. The goal of the experiment was the construction of the first deep ocean high energy neutrino detector, to be placed at 4800 m depth in the Pacific Ocean off Keahole Point on the Big Island of Hawaii. A few years ago, a European conference with Cosmic experiments was organized at CERN as they were projects like DUMAND in Hawaii. Along with the conference, a temporary exhibition was organised as well. It was a collaboration of institutions from Germany, Japan, Switzerland and the U.S.A. CERN had borrowed equipment and objects from different institutes around the world, including this detector of the DUMAND experiment. Most of the equipment were sent back to the institutes, however this detector sphere was offered to a CERN member of the personnel.

  15. Detector applications

    International Nuclear Information System (INIS)

    Pehl, R.H.

    1977-10-01

    Semiconductor detectors are now applied to a very wide range of problems. The combination of relatively low cost, excellent energy resolution, and simultaneous broad energy-spectrum analysis is uniquely suited to many applications in both basic and applied physics. Alternative techniques, such as magnetic spectrometers for charged-particle spectroscopy, while offering better energy resolution, are bulky, expensive, and usually far more difficult to use. Furthermore, they do not directly provide the broad energy-spectrum measurements easily accomplished using semiconductor detectors. Scintillation detectors, which are approximately equivalent to semiconductor detectors in convenience and cost, exhibit 10 to 100 times worse energy resolution. However, their high efficiency and large potential size recommend their use in some measurements

  16. Smoke detectors

    International Nuclear Information System (INIS)

    Bryant, J.; Howes, J.H.; Smout, D.W.S.

    1979-01-01

    A smoke detector is described which provides a smoke sensing detector and an indicating device and in which a radioactive substance is used in conjunction with two ionisation chambers. The system includes an outer electrode, a collector electrode and an inner electrode which is made of or supports the radioactive substance which, in this case, is 241 Am. The invention takes advantage of the fact that smoke particles can be allowed to enter freely the inner ionisation chamber. (U.K.)

  17. Radiation detector

    International Nuclear Information System (INIS)

    Gillies, W.

    1980-01-01

    The radiation detector for measuring e.g. a neutron flux consists of a central emitter, an insulating shell arranged around it, and a tube-shaped collector enclosing both. The emitter itself is composed of a great number of stranded, spiral wires of small diameter giving a defined flexibility to the detector. For emitter material Pt, Rh, V, Co, Ce, Os or Ta may be used. (DG) [de

  18. Dual energy CT: New horizon in medical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Goo, Jin Mo [Dept. of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2017-08-01

    Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

  19. Dual-Energy CT: New Horizon in Medical Imaging.

    Science.gov (United States)

    Goo, Hyun Woo; Goo, Jin Mo

    2017-01-01

    Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

  20. Development of the LBNL positron emission mammography camera

    International Nuclear Information System (INIS)

    Huber, Jennifer S.; Choong, Woon-Seng; Wang, Jimmy; Maltz, Jonathon S.; Qi, Jinyi; Mandelli, Emanuele; Moses, William W.

    2002-01-01

    We present the construction status of the LBNL Positron Emission Mammography (PEM) camera, which utilizes a PET detector module with depth of interaction measurement consisting of 64 LSO crystals (3x3x30 mm3) coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of silicon photodiodes (PDs). The PMT provides an accurate timing pulse, the PDs identify the crystal of interaction, the sum provides a total energy signal, and the PD/(PD+PMT) ratio determines the depth of interaction. We have completed construction of all 42 PEM detector modules. All data acquisition electronics have been completed, fully tested and loaded onto the gantry. We have demonstrated that all functions of the custom IC work using the production rigid-flex boards and data acquisition system. Preliminary detector module characterization and coincidence data have been taken using the production system, including initial images

  1. Astronomy and the camera obscura

    Science.gov (United States)

    Feist, M.

    2000-02-01

    The camera obscura (from Latin meaning darkened chamber) is a simple optical device with a long history. In the form considered here, it can be traced back to 1550. It had its heyday during the Victorian era when it was to be found at the seaside as a tourist attraction or sideshow. It was also used as an artist's drawing aid and, in 1620, the famous astronomer-mathematician, Johannes Kepler used a small tent camera obscura to trace the scenery.

  2. The future of consumer cameras

    Science.gov (United States)

    Battiato, Sebastiano; Moltisanti, Marco

    2015-03-01

    In the last two decades multimedia, and in particular imaging devices (camcorders, tablets, mobile phones, etc.) have been dramatically diffused. Moreover the increasing of their computational performances, combined with an higher storage capability, allows them to process large amount of data. In this paper an overview of the current trends of consumer cameras market and technology will be given, providing also some details about the recent past (from Digital Still Camera up today) and forthcoming key issues.

  3. An energy-subtraction Compton scatter camera design for in vivo medical imaging of radiopharmaceuticals

    International Nuclear Information System (INIS)

    Rohe, R.C.; Valentine, J.D.

    1996-01-01

    A Compton scatter camera (CSC) design is proposed for imaging radioisotopes used as biotracers. A clinical version may increase sensitivity by a factor of over 100, while maintaining or improving spatial resolution, as compared with existing Anger cameras that use lead collimators. This novel approach is based on using energy subtraction (ΔE = E 0 - E SC , where E 0 , ΔE, and E SC are the energy of the emitted gamma ray, the energy deposited by the initial Compton scatter, and the energy of the Compton scattered photon) to determine the amount of energy deposited in the primary system. The energy subtraction approach allows the requirement of high energy resolution to be placed on a secondary detector system instead of the primary detector system. Requiring primary system high energy resolution has significantly limited previous CSC designs for medical imaging applications. Furthermore, this approach is dependent on optimizing the camera design for data acquisition of gamma rays that undergo only one Compton scatter in a low-Z primary detector system followed by a total absorption of the Compton scattered photon in a high-Z secondary detector system. The proposed approach allows for a more compact primary detector system, a more simplified pulse processing interface, and a much less complicated detector cooling scheme as compared with previous CSC designs. Analytical calculations and Monte Carlo simulation results for some specific detector materials and geometries are presented

  4. Science, conservation, and camera traps

    Science.gov (United States)

    Nichols, James D.; Karanth, K. Ullas; O'Connel, Allan F.; O'Connell, Allan F.; Nichols, James D.; Karanth, K. Ullas

    2011-01-01

    Biologists commonly perceive camera traps as a new tool that enables them to enter the hitherto secret world of wild animals. Camera traps are being used in a wide range of studies dealing with animal ecology, behavior, and conservation. Our intention in this volume is not to simply present the various uses of camera traps, but to focus on their use in the conduct of science and conservation. In this chapter, we provide an overview of these two broad classes of endeavor and sketch the manner in which camera traps are likely to be able to contribute to them. Our main point here is that neither photographs of individual animals, nor detection history data, nor parameter estimates generated from detection histories are the ultimate objective of a camera trap study directed at either science or management. Instead, the ultimate objectives are best viewed as either gaining an understanding of how ecological systems work (science) or trying to make wise decisions that move systems from less desirable to more desirable states (conservation, management). Therefore, we briefly describe here basic approaches to science and management, emphasizing the role of field data and associated analyses in these processes. We provide examples of ways in which camera trap data can inform science and management.

  5. Computing camera heading: A study

    Science.gov (United States)

    Zhang, John Jiaxiang

    2000-08-01

    An accurate estimate of the motion of a camera is a crucial first step for the 3D reconstruction of sites, objects, and buildings from video. Solutions to the camera heading problem can be readily applied to many areas, such as robotic navigation, surgical operation, video special effects, multimedia, and lately even in internet commerce. From image sequences of a real world scene, the problem is to calculate the directions of the camera translations. The presence of rotations makes this problem very hard. This is because rotations and translations can have similar effects on the images, and are thus hard to tell apart. However, the visual angles between the projection rays of point pairs are unaffected by rotations, and their changes over time contain sufficient information to determine the direction of camera translation. We developed a new formulation of the visual angle disparity approach, first introduced by Tomasi, to the camera heading problem. Our new derivation makes theoretical analysis possible. Most notably, a theorem is obtained that locates all possible singularities of the residual function for the underlying optimization problem. This allows identifying all computation trouble spots beforehand, and to design reliable and accurate computational optimization methods. A bootstrap-jackknife resampling method simultaneously reduces complexity and tolerates outliers well. Experiments with image sequences show accurate results when compared with the true camera motion as measured with mechanical devices.

  6. A Detector for Combined SPECT/CT. Final Technical Report

    International Nuclear Information System (INIS)

    Vivek Nagarkar

    2006-01-01

    these data to refine deposition protocols; (4) Develop suitable designs of a collimator to be fabricated during the Phase II; (5) Integrate thick CsI(Tl) films into the existing IGCCD camera to form a prototype dual-imaging detector module; (6) Conduct evaluation of the prototype SPECT/CT detector to determine its suitability for x-ray CT and radionuclide imaging; and (7) Write the Phase I final report and prepare the Phase II research plan. Our work in Phase I has not only accomplished all the above stated goals, but has surpassed them in many aspects. The data presented in the report below show that the proposed combined detector will not only minimize the complexity and cost associated with conventional readouts, but will also improve system reliability necessary for the development of a dual modality system. This is a substantial accomplishment, which brings us a step closer to our Phase II goal of developing a much larger area, higher pixel resolution detector and minimizes risk associated with implementation of the proposed design

  7. A Compton camera application for the GAMOS GEANT4-based framework

    Energy Technology Data Exchange (ETDEWEB)

    Harkness, L.J., E-mail: ljh@ns.ph.liv.ac.uk [Oliver Lodge Laboratory, The University of Liverpool, Liverpool L69 7ZE (United Kingdom); Arce, P. [Department of Basic Research, CIEMAT, Madrid (Spain); Judson, D.S.; Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Dormand, J.; Jones, M.; Nolan, P.J.; Sampson, J.A.; Scraggs, D.P.; Sweeney, A. [Oliver Lodge Laboratory, The University of Liverpool, Liverpool L69 7ZE (United Kingdom); Lazarus, I.; Simpson, J. [STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom)

    2012-04-11

    Compton camera systems can be used to image sources of gamma radiation in a variety of applications such as nuclear medicine, homeland security and nuclear decommissioning. To locate gamma-ray sources, a Compton camera employs electronic collimation, utilising Compton kinematics to reconstruct the paths of gamma rays which interact within the detectors. The main benefit of this technique is the ability to accurately identify and locate sources of gamma radiation within a wide field of view, vastly improving the efficiency and specificity over existing devices. Potential advantages of this imaging technique, along with advances in detector technology, have brought about a rapidly expanding area of research into the optimisation of Compton camera systems, which relies on significant input from Monte-Carlo simulations. In this paper, the functionality of a Compton camera application that has been integrated into GAMOS, the GEANT4-based Architecture for Medicine-Oriented Simulations, is described. The application simplifies the use of GEANT4 for Monte-Carlo investigations by employing a script based language and plug-in technology. To demonstrate the use of the Compton camera application, simulated data have been generated using the GAMOS application and acquired through experiment for a preliminary validation, using a Compton camera configured with double sided high purity germanium strip detectors. Energy spectra and reconstructed images for the data sets are presented.

  8. 32x32 HgCdTe/CCD infrared camera for the 2-5 micron range

    International Nuclear Information System (INIS)

    Monin, J.L.; Vauglin, I.; Sibille, F.

    1988-01-01

    The paper presents a complete infrared camera system, based on a high electron capacity detector (HgCdTe/CCD), that has been used under high background conditions to generate astronomical images. The performance of the system and some results are presented, and the use of such a detector in astronomy is discussed. 8 references

  9. Dual Diagnosis - Multiple Languages

    Science.gov (United States)

    ... National Library of Medicine Comorbidity or dual diagnosis - Opioid addiction, part 9 - English PDF Comorbidity or dual diagnosis - Opioid addiction, part 9 - español (Spanish) PDF Comorbidity or dual ...

  10. Geant4 simulation of a 3D high resolution gamma camera

    International Nuclear Information System (INIS)

    Akhdar, H.; Kezzar, K.; Aksouh, F.; Assemi, N.; AlGhamdi, S.; AlGarawi, M.; Gerl, J.

    2015-01-01

    The aim of this work is to develop a 3D gamma camera with high position resolution and sensitivity relying on both distance/absorption and Compton scattering techniques and without using any passive collimation. The proposed gamma camera is simulated in order to predict its performance using the full benefit of Geant4 features that allow the construction of the needed geometry of the detectors, have full control of the incident gamma particles and study the response of the detector in order to test the suggested geometries. Three different geometries are simulated and each configuration is tested with three different scintillation materials (LaBr3, LYSO and CeBr3)

  11. Polarimetric Edge Detector Based on the Complex Wishart Distribution

    DEFF Research Database (Denmark)

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

    2001-01-01

    polarimetric edge detector provides a constant false alarm rate and it utilizes the full polarimetric information. The edge detector has been applied to polarimetric SAR data from the Danish dual-frequency, airborne polarimetric SAR, EMISAR. The results show clearly an improved edge detection performance...

  12. Novel Heterongineered Detectors for Multi-Color Infrared Sensing

    Science.gov (United States)

    2012-01-30

    a) Sequential but collocated two-color detection capabilities of type II InAsGaSb SLS detector based on an nBn design and (b) Simultaneous and...captions: Figure 1. Heterostructure Schematic of (a) PbIbN Design, (b) Dual Color Detector Design with flat band energy lineups . Figure 2. (a) Spectral

  13. A Compton camera for spectroscopic imaging from 100 keV to 1 MeV

    International Nuclear Information System (INIS)

    Earnhart, J.R.D.

    1998-01-01

    A review of spectroscopic imaging issues, applications, and technology is presented. Compton cameras based on solid state semiconductor detectors stands out as the best system for the nondestructive assay of special nuclear materials. A camera for this application has been designed based on an efficient specific purpose Monte Carlo code developed for this project. Preliminary experiments have been performed which demonstrate the validity of the Compton camera concept and the accuracy of the code. Based on these results, a portable prototype system is in development. Proposed future work is addressed

  14. Radon detectors for continuous environmental monitoring applications

    International Nuclear Information System (INIS)

    Sisoutham, O.; Werczynski, S.; Chambers, S.; Zahorowski, W.

    2003-01-01

    The two-filter method is presently the best technique available for real-time low-level counting of atmospheric 222 Rn. The Australian Nuclear Science and Technology Organisation has developed and deployed a range of dual flow loop, two-filter radon detectors around the world for various applications. The detectors have a response time of 45 minutes, and can be custom built for specific purposes. The largest detectors have a lower limit of detection of ∼10 mBq m -3

  15. Applying and extending ISO/TC42 digital camera resolution standards to mobile imaging products

    Science.gov (United States)

    Williams, Don; Burns, Peter D.

    2007-01-01

    There are no fundamental differences between today's mobile telephone cameras and consumer digital still cameras that suggest many existing ISO imaging performance standards do not apply. To the extent that they have lenses, color filter arrays, detectors, apertures, image processing, and are hand held, there really are no operational or architectural differences. Despite this, there are currently differences in the levels of imaging performance. These are driven by physical and economic constraints, and image-capture conditions. Several ISO standards for resolution, well established for digital consumer digital cameras, require care when applied to the current generation of cell phone cameras. In particular, accommodation of optical flare, shading non-uniformity and distortion are recommended. We offer proposals for the application of existing ISO imaging resolution performance standards to mobile imaging products, and suggestions for extending performance standards to the characteristic behavior of camera phones.

  16. Common aperture multispectral spotter camera: Spectro XR

    Science.gov (United States)

    Petrushevsky, Vladimir; Freiman, Dov; Diamant, Idan; Giladi, Shira; Leibovich, Maor

    2017-10-01

    The Spectro XRTM is an advanced color/NIR/SWIR/MWIR 16'' payload recently developed by Elbit Systems / ELOP. The payload's primary sensor is a spotter camera with common 7'' aperture. The sensor suite includes also MWIR zoom, EO zoom, laser designator or rangefinder, laser pointer / illuminator and laser spot tracker. Rigid structure, vibration damping and 4-axes gimbals enable high level of line-of-sight stabilization. The payload's list of features include multi-target video tracker, precise boresight, strap-on IMU, embedded moving map, geodetic calculations suite, and image fusion. The paper describes main technical characteristics of the spotter camera. Visible-quality, all-metal front catadioptric telescope maintains optical performance in wide range of environmental conditions. High-efficiency coatings separate the incoming light into EO, SWIR and MWIR band channels. Both EO and SWIR bands have dual FOV and 3 spectral filters each. Several variants of focal plane array formats are supported. The common aperture design facilitates superior DRI performance in EO and SWIR, in comparison to the conventionally configured payloads. Special spectral calibration and color correction extend the effective range of color imaging. An advanced CMOS FPA and low F-number of the optics facilitate low light performance. SWIR band provides further atmospheric penetration, as well as see-spot capability at especially long ranges, due to asynchronous pulse detection. MWIR band has good sharpness in the entire field-of-view and (with full HD FPA) delivers amount of detail far exceeding one of VGA-equipped FLIRs. The Spectro XR offers level of performance typically associated with larger and heavier payloads.

  17. Some properties of dual and approximate dual of fusion frames

    OpenAIRE

    Arefijamaal, Ali Akbar; Neyshaburi, Fahimeh Arabyani

    2016-01-01

    In this paper we extend the notion of approximate dual to fusion frames and present some approaches to obtain dual and approximate alternate dual fusion frames. Also, we study the stability of dual and approximate alternate dual fusion frames.

  18. Constrained optimization for position calibration of an NMR field camera.

    Science.gov (United States)

    Chang, Paul; Nassirpour, Sahar; Eschelbach, Martin; Scheffler, Klaus; Henning, Anke

    2018-07-01

    Knowledge of the positions of field probes in an NMR field camera is necessary for monitoring the B 0 field. The typical method of estimating these positions is by switching the gradients with known strengths and calculating the positions using the phases of the FIDs. We investigated improving the accuracy of estimating the probe positions and analyzed the effect of inaccurate estimations on field monitoring. The field probe positions were estimated by 1) assuming ideal gradient fields, 2) using measured gradient fields (including nonlinearities), and 3) using measured gradient fields with relative position constraints. The fields measured with the NMR field camera were compared to fields acquired using a dual-echo gradient recalled echo B 0 mapping sequence. Comparisons were done for shim fields from second- to fourth-order shim terms. The position estimation was the most accurate when relative position constraints were used in conjunction with measured (nonlinear) gradient fields. The effect of more accurate position estimates was seen when compared to fields measured using a B 0 mapping sequence (up to 10%-15% more accurate for some shim fields). The models acquired from the field camera are sensitive to noise due to the low number of spatial sample points. Position estimation of field probes in an NMR camera can be improved using relative position constraints and nonlinear gradient fields. Magn Reson Med 80:380-390, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  19. Gamma camera investigations using an on-line computer system

    International Nuclear Information System (INIS)

    Vikterloef, K.J.; Beckman, K.-W.; Berne, E.; Liljenfors, B.

    1974-01-01

    A computer system for use with a gamma camera has been developed by Oerebro Regional Hospital and Nukab AB using a PDP 8/e with a 12K core memory connected to a Selektronik gamma camera. It is possible to register, without loss, pictures of high (5kcps) pulse frequency, two separate channels with identical coordinates, fast dynamic functions down to 5 pictures/second, and to perform statistical smoothing and subtraction of two separate pictures. Experience has shown these possibilities to be so valuable that one has difficulty in thinking of a scanning system without them. This applies not only to sophisticated investigations, e.g. dual isotope registration, but also in conventional scanning for avoiding false positive interpretations and increasing the precision. It is possible at relatively low cost to add a dosage planning system. (JIW)

  20. Single-Pulse Dual-Energy Mammography Using a Binary Screen Coupled to Dual CCD Cameras

    Science.gov (United States)

    1999-08-01

    Fossum, "Active pixel sensors—Are CCD’s Dinosaurs ?," Proc. SPIE 1900, 2-14 (1993). "S. Mendis, S. E. Kemeny, R. Gee, B. Pain, and E. R. Fossum, "Progress...Clin Oncol 13:1470-1477, 1995 12. Wahl RL, Zasadny K, Helvie M, et al: Metabolic monitoring of breast cancer chemohormonotherapy using posi- tron

  1. Shaped detector

    International Nuclear Information System (INIS)

    Carlson, R.W.

    1981-01-01

    A radiation detector or detector array which has a non-constant spatial response, is disclosed individually and in combination with a tomographic scanner. The detector has a first dimension which is oriented parallel to the plane of the scan circle in the scanner. Along the first dimension, the detector is most responsive to radiation received along a centered segment of the dimension and less responsive to radiation received along edge segments. This non-constant spatial response can be achieved in a detector comprised of a scintillation crystal and a photoelectric transducer. The scintillation crystal in one embodiment is composed of three crystals arranged in layers, with the center crystal having the greatest light conversion efficiency. In another embodiment, the crystal is covered with a reflective substance around the center segment and a less reflective substance around the remainder. In another embodiment, an optical coupling which transmits light from adjacent the center segment with the greatest intensity couples the scintillation crystal and the photoelectric transducer. In yet another embodiment, the photoelectric transducer comprises three photodiodes, one receiving light produced adjacent the central segment and the other two receiving light produced adjacent the edge segments. The outputs of the three photodiodes are combined with a differential amplifier

  2. Sub-Camera Calibration of a Penta-Camera

    Science.gov (United States)

    Jacobsen, K.; Gerke, M.

    2016-03-01

    Penta cameras consisting of a nadir and four inclined cameras are becoming more and more popular, having the advantage of imaging also facades in built up areas from four directions. Such system cameras require a boresight calibration of the geometric relation of the cameras to each other, but also a calibration of the sub-cameras. Based on data sets of the ISPRS/EuroSDR benchmark for multi platform photogrammetry the inner orientation of the used IGI Penta DigiCAM has been analyzed. The required image coordinates of the blocks Dortmund and Zeche Zollern have been determined by Pix4Dmapper and have been independently adjusted and analyzed by program system BLUH. With 4.1 million image points in 314 images respectively 3.9 million image points in 248 images a dense matching was provided by Pix4Dmapper. With up to 19 respectively 29 images per object point the images are well connected, nevertheless the high number of images per object point are concentrated to the block centres while the inclined images outside the block centre are satisfying but not very strongly connected. This leads to very high values for the Student test (T-test) of the finally used additional parameters or in other words, additional parameters are highly significant. The estimated radial symmetric distortion of the nadir sub-camera corresponds to the laboratory calibration of IGI, but there are still radial symmetric distortions also for the inclined cameras with a size exceeding 5μm even if mentioned as negligible based on the laboratory calibration. Radial and tangential effects of the image corners are limited but still available. Remarkable angular affine systematic image errors can be seen especially in the block Zeche Zollern. Such deformations are unusual for digital matrix cameras, but it can be caused by the correlation between inner and exterior orientation if only parallel flight lines are used. With exception of the angular affinity the systematic image errors for corresponding

  3. A space-time tomography algorithm for the five-camera soft X-ray diagnostic at RTP

    Energy Technology Data Exchange (ETDEWEB)

    Lyadina, E.S.; Tanzi, C.P.; Cruz, D.F. da; Donne, A.J.H. [FOM-Instituut voor Plasmafysica, Rijnhuizen (Netherlands)

    1993-12-31

    A five-camera soft x-ray with 80 detector channels has been installed on the RTP tokamak with the object of studying MHD processes with a relatively high poloidal mode number (m=4). Numerical tomographic reconstruction algorithms used to reconstruct the plasma emissivity profile are constrained by the characteristics of the system. Especially high poloidal harmonics, which can be resolved due to the high number of cameras, can be strongly distorted by stochastic and systematic errors. Furthermore, small uncertainties in the relative position of the cameras in a multiple camera system can lead to strong artefacts in the reconstruction. (author) 6 refs., 4 figs.

  4. The large Debye-Scherrer camera installed at SPring-8 BL02B2 for charge density studies

    CERN Document Server

    Nishibori, E; Kato, K; Sakata, M; Kubota, Y; Aoyagi, S; Kuroiwa, Y; Yamakata, M; Ikeda, N

    2001-01-01

    The design and performance of a large Debye-Scherrer Camera with imaging plate (IP) as a detector, which was very recently installed at SPring-8, BL02B2, is reported. By taking advantage of high beam quality of SPring-8, the camera enables one a rapid collection of a high counting statistics and high angular resolution powder pattern, which can lead to accurate structure analyses. The camera also provides easy access to structural changes at varied temperatures between 15-1000 K. The camera provides a rapid and accurate powder diffraction system utilizing third generation SR.

  5. Upgrade of the JET gamma-ray cameras

    International Nuclear Information System (INIS)

    Soare, S.; Curuia, M.; Anghel, M.; Constantin, M.; David, E.; Craciunescu, T.; Falie, D.; Pantea, A.; Tiseanu, I.; Kiptily, V.; Prior, P.; Edlington, T.; Griph, S.; Krivchenkov, Y.; Loughlin, M.; Popovichev, S.; Riccardo, V; Syme, B.; Thompson, V.; Lengar, I.; Murari, A.; Bonheure, G.; Le Guern, F.

    2007-01-01

    Full text: The JET gamma-ray camera diagnostics have already provided valuable information on the gamma-ray imaging of fast ion in JET plasmas. The applicability of gamma-ray imaging to high performance deuterium and deuterium-tritium JET discharges is strongly dependent on the fulfilment of rather strict requirements for the characterisation of the neutron and gamma-ray radiation fields. These requirements have to be satisfied within very stringent boundary conditions for the design, such as the requirement of minimum impact on the co-existing neutron camera diagnostics. The JET Gamma-Ray Cameras (GRC) upgrade project deals with these issues with particular emphasis on the design of appropriate neutron/gamma-ray filters ('neutron attenuators'). Several design versions have been developed and evaluated for the JET GRC neutron attenuators at the conceptual design level. The main design parameter was the neutron attenuation factor. The two design solutions, that have been finally chosen and developed at the level of scheme design, consist of: a) one quasi-crescent shaped neutron attenuator (for the horizontal camera) and b) two quasi-trapezoid shaped neutron attenuators (for the vertical one). The second design solution has different attenuation lengths: a short version, to be used together with the horizontal attenuator for deuterium discharges, and a long version to be used for high performance deuterium and DT discharges. Various neutron-attenuating materials have been considered (lithium hydride with natural isotopic composition and 6 Li enriched, light and heavy water, polyethylene). Pure light water was finally chosen as the attenuating material for the JET gamma-ray cameras. The neutron attenuators will be steered in and out of the detector line-of-sight by means of an electro-pneumatic steering and control system. The MCNP code was used for neutron and gamma ray transport in order to evaluate the effect of the neutron attenuators on the neutron field of the

  6. Time response characteristics of X-ray detector system on Silex-Ⅰ laser facility

    International Nuclear Information System (INIS)

    Yi Rongqing; He Xiao'an; Li Hang; Du Huabing; Zhang Haiying; Cao Zhurong

    2013-01-01

    On the Silex-Ⅰ laser facility, the time response characteristics of XRD detector were studied. A laser with a pulse of 32 fs and a wavelength of 800 nm was used to irradiate a plane Au target. X-ray calibrated method of time of exposure X-ray framing camera and time resolution of X-ray streak camera was explored. The time response characteristics of XRD detector and time process of X-ray emission were obtained from experiment. We obtained X-ray calibration method of time of exposure X-ray framing camera and time resolution of X-ray streak camera. (authors)

  7. The fly's eye camera system

    Science.gov (United States)

    Mészáros, L.; Pál, A.; Csépány, G.; Jaskó, A.; Vida, K.; Oláh, K.; Mezö, G.

    2014-12-01

    We introduce the Fly's Eye Camera System, an all-sky monitoring device intended to perform time domain astronomy. This camera system design will provide complementary data sets for other synoptic sky surveys such as LSST or Pan-STARRS. The effective field of view is obtained by 19 cameras arranged in a spherical mosaic form. These individual cameras of the device stand on a hexapod mount that is fully capable of achieving sidereal tracking for the subsequent exposures. This platform has many advantages. First of all it requires only one type of moving component and does not include unique parts. Hence this design not only eliminates problems implied by unique elements, but the redundancy of the hexapod allows smooth operations even if one or two of the legs are stuck. In addition, it can calibrate itself by observed stars independently from both the geographical location (including northen and southern hemisphere) and the polar alignment of the full mount. All mechanical elements and electronics are designed within the confines of our institute Konkoly Observatory. Currently, our instrument is in testing phase with an operating hexapod and reduced number of cameras.

  8. Event detection intelligent camera development

    International Nuclear Information System (INIS)

    Szappanos, A.; Kocsis, G.; Molnar, A.; Sarkozi, J.; Zoletnik, S.

    2008-01-01

    A new camera system 'event detection intelligent camera' (EDICAM) is being developed for the video diagnostics of W-7X stellarator, which consists of 10 distinct and standalone measurement channels each holding a camera. Different operation modes will be implemented for continuous and for triggered readout as well. Hardware level trigger signals will be generated from real time image processing algorithms optimized for digital signal processor (DSP) and field programmable gate array (FPGA) architectures. At full resolution a camera sends 12 bit sampled 1280 x 1024 pixels with 444 fps which means 1.43 Terabyte over half an hour. To analyse such a huge amount of data is time consuming and has a high computational complexity. We plan to overcome this problem by EDICAM's preprocessing concepts. EDICAM camera system integrates all the advantages of CMOS sensor chip technology and fast network connections. EDICAM is built up from three different modules with two interfaces. A sensor module (SM) with reduced hardware and functional elements to reach a small and compact size and robust action in harmful environment as well. An image processing and control unit (IPCU) module handles the entire user predefined events and runs image processing algorithms to generate trigger signals. Finally a 10 Gigabit Ethernet compatible image readout card functions as the network interface for the PC. In this contribution all the concepts of EDICAM and the functions of the distinct modules are described

  9. A fast parallel encoding scheme for the Anger camera

    International Nuclear Information System (INIS)

    Seeger, P.A.

    1983-01-01

    An Anger camera is a position-sensitive scintillation detector with a continuous scintillator and a relatively small number of photomultipliers. Light from any one event disperses through a coupling plate to strike several photomultipliers. An air gap between the scintillator and the disperser limits the divergence of the photons by total internal reflection, and the radius of the distribution is proportional to the thickness of the disperser. The camera layout is illustrated and described. The basic unit for two-dimensional position determination is a ''receptive field'' of seven photomultipliers, the detector illustrated has three overlapping fields. In the standard Anger camera, position is determined by finding the centroid of the photomultiplier signals from weighted sums over all tubes of the array. The simplest case (a single field of seven tubes) is described first and then it is shown how this can be expanded to arbitrary size by combining simple circuits. Attention is drawn to the close analogy of this circuit to the structure (and function) of vertebrate visual cortex. (author)

  10. A simple data loss model for positron camera systems

    International Nuclear Information System (INIS)

    Eriksson, L.; Dahlbom, M.

    1994-01-01

    A simple model to describe data losses in PET cameras is presented. The model is not intended to be used primarily for dead time corrections in existing scanners, although this is possible. Instead the model is intended to be used for data simulations in order to determine the figures of merit of future camera systems, based on data handling state-of-art solutions. The model assumes the data loss to be factorized into two components, one describing the detector or block-detector performance and the other the remaining data handling such as coincidence determinations, data transfer and data storage. Two modern positron camera systems have been investigated in terms of this model. These are the Siemens-CTI ECAT EXACT and ECAT EXACT HR systems, which both have an axial field-of-view (FOV) of about 15 cm. They both have retractable septa and can acquire data from the whole volume within the FOV and can reconstruct volume image data. An example is given how to use the model for live time calculation in a futuristic large axial FOV cylindrical system

  11. BES detector

    International Nuclear Information System (INIS)

    Bai, J.Z.; Bian, Q.; Chen, G.M.; Chen, L.J.; Chen, S.N.; Chen, Y.Q.; Chen, Z.Q.; Chi, Y.K.; Cui, H.C.; Cui, X.Z.; Deng, S.S.; Deng, Y.W.; Ding, H.L.; Dong, B.Z.; Dong, X.S.; Du, X.; Du, Z.Z.; Feng, C.; Feng, Z.; Fu, Z.S.; Gao, C.S.; Gao, M.L.; Gao, S.Q.; Gao, W.X.; Gao, Y.N.; Gu, S.D.; Gu, W.X.; Guan, Y.Z.; Guo, H.F.; Guo, Y.N.; Guo, Y.Y.; Han, S.W.; Han, Y.; Hao, W.; He, J.; He, K.R.; He, M.J.; Hou, X.J.; Hu, G.Y.; Hu, J.S.; Hu, J.W.; Huang, D.Q.; Huang, Y.Z.; Jia, Q.P.; Jiang, C.H.; Ju, Q.; Lai, Y.F.; Lang, P.F.; Li, D.S.; Li, F.; Li, H.; Li Jia; Li, J.T.; Li Jin; Li, L.L.; Li, P.Q.; Li, Q.M.; Li, R.B.; Li, S.Q.; Li, W.; Li, W.G.; Li, Z.X.; Liang, G.N.; Lin, F.C.; Lin, S.Z.; Lin, W.; Liu, Q.; Liu, R.G.; Liu, W.; Liu, X.; Liu, Z.A.; Liu, Z.Y.; Lu, C.G.; Lu, W.D.; Lu, Z.Y.; Lu, J.G.; Ma, D.H.; Ma, E.C.; Ma, J.M.; Mao, H.S.; Mao, Z.P.; Meng, X.C.; Ni, H.L.; Nie, J.; Nie, Z.D.; Niu, W.P.; Pan, L.J.; Qi, N.D.; Qian, J.J.; Qu, Y.H.; Que, Y.K.; Rong, G.; Ruan, T.Z.; Shao, Y.Y.; Shen, B.W.; Shen, D.L.; Shen, J.; Sheng, H.Y.; Sheng, J.P.; Shi, H.Z.; Song, X.F.; Sun, H.S.; Tang, F.K.; Tang, S.Q.; Tian, W.H.; Wang, F.; Wang, G.Y.; Wang, J.G.; Wang, J.Y.; Wang, L.S.; Wang, L.Z.; Wang, M.; Wang, P.; Wang, P.L.; Wang, S.M.; Wang, S.Q.; Wang, T.J.; Wang, X.W.; Wang, Y.Y.; Wang, Z.H.; Wang, Z.J.; Wei, C.L.; Wei, Z.Z.; Wu, J.W.; Wu, S.H.; Wu, S.Q.; Wu, W.M.; Wu, X.D.; Wu, Z.D.; Xi, D.M.; Xia, X.M.; Xiao, J.; Xie, P.P.; Xie, X.X.; Xu, J.G.; Xu, R.S.; Xu, Z.Q.; Xuan, B.C.; Xue, S.T.; Yan, J.; Yan, S.P.; Yan, W.G.; Yang, C.Z.; Yang, C.M.; Yang, C.Y.; Yang, X.F.; Yang, X.R.; Ye, M.H.; Yu, C.H.; Yu, C.S.; Yu, Z.Q.; Zhang, B.Y.; Zhang, C.D.; Zhang, C.C.; Zhang, C.Y.; Zhang, D.H.; Zhang, G.; Zhang, H.Y.; Zhang, H.L.; Zhang, J.W.; Zhang, L.S.; Zhang, S.Q.; Zhang, Y.P.; Zhang, Y.; Zhang, Y.M.; Zhao, D.X.; Zhao, J.W.; Zhao, M.; Zhao, P.D.; Zhao, P.P.; Zhao, W.R.; Zhao, Z.G.; Zhao, Z.Q.; Zheng, J.P.; Zheng, L.S.; Zheng, M.; Zheng, W.S.; Zheng, Z.P.; Zhong, G.P.; Zhou, G.P.; Zhou, H.S.; Zhou, J.; Zhou Li; Zhou Lin; Zhou, M.; Zhou, Y.S.; Zhou, Y.H.; Zhu, G.S.; Zhu, Q.M.; Zhu, S.G.; Zhu, Y.C.; Zhu, Y.S.; Zhuang, B.A.

    1994-01-01

    The Beijing Spectrometer (BES) is a general purpose solenoidal detector at the Beijing Electron Positron Collider (BEPC). It is designed to study exclusive final states in e + e - annihilations at the center of mass energy from 3.0 to 5.6 GeV. This requires large solid angle coverage combined with good charged particle momentum resolution, good particle identification and high photon detection efficiency at low energies. In this paper we describe the construction and the performance of BES detector. (orig.)

  12. Video camera use at nuclear power plants

    International Nuclear Information System (INIS)

    Estabrook, M.L.; Langan, M.O.; Owen, D.E.

    1990-08-01

    A survey of US nuclear power plants was conducted to evaluate video camera use in plant operations, and determine equipment used and the benefits realized. Basic closed circuit television camera (CCTV) systems are described and video camera operation principles are reviewed. Plant approaches for implementing video camera use are discussed, as are equipment selection issues such as setting task objectives, radiation effects on cameras, and the use of disposal cameras. Specific plant applications are presented and the video equipment used is described. The benefits of video camera use --- mainly reduced radiation exposure and increased productivity --- are discussed and quantified. 15 refs., 6 figs

  13. Neutron imaging system based on a video camera

    International Nuclear Information System (INIS)

    Dinca, M.

    2004-01-01

    possess versatile and unique readout capabilities that have established their utility in scientific and especially for radiation field applications. A detector for neutron radiography based on a cooled CID camera offers some capabilities, as follows: - Extended linear dynamic range up to 109 without blooming or streaking; - Arbitrary pixel selection and nondestructive readout makes it possible to introduce a high degree of exposure control to low-light viewing of static scenes; - Read multiple areas of interest of an image within a given frame at higher rates; - Wide spectral response (185 nm - 1100 nm); - CIDs tolerate high radiation environments up to 3 Mrad integrated dose; - The contiguous pixel structure of CID arrays contributes to accurate imaging because there are virtually no opaque areas between pixels. (author)

  14. Target-Tracking Camera for a Metrology System

    Science.gov (United States)

    Liebe, Carl; Bartman, Randall; Chapsky, Jacob; Abramovici, Alexander; Brown, David

    2009-01-01

    An analog electronic camera that is part of a metrology system measures the varying direction to a light-emitting diode that serves as a bright point target. In the original application for which the camera was developed, the metrological system is used to determine the varying relative positions of radiating elements of an airborne synthetic aperture-radar (SAR) antenna as the airplane flexes during flight; precise knowledge of the relative positions as a function of time is needed for processing SAR readings. It has been common metrology system practice to measure the varying direction to a bright target by use of an electronic camera of the charge-coupled-device or active-pixel-sensor type. A major disadvantage of this practice arises from the necessity of reading out and digitizing the outputs from a large number of pixels and processing the resulting digital values in a computer to determine the centroid of a target: Because of the time taken by the readout, digitization, and computation, the update rate is limited to tens of hertz. In contrast, the analog nature of the present camera makes it possible to achieve an update rate of hundreds of hertz, and no computer is needed to determine the centroid. The camera is based on a position-sensitive detector (PSD), which is a rectangular photodiode with output contacts at opposite ends. PSDs are usually used in triangulation for measuring small distances. PSDs are manufactured in both one- and two-dimensional versions. Because it is very difficult to calibrate two-dimensional PSDs accurately, the focal-plane sensors used in this camera are two orthogonally mounted one-dimensional PSDs.

  15. The GISMO-2 Bolometer Camera

    Science.gov (United States)

    Staguhn, Johannes G.; Benford, Dominic J.; Fixsen, Dale J.; Hilton, Gene; Irwin, Kent D.; Jhabvala, Christine A.; Kovacs, Attila; Leclercq, Samuel; Maher, Stephen F.; Miller, Timothy M.; hide

    2012-01-01

    We present the concept for the GISMO-2 bolometer camera) which we build for background-limited operation at the IRAM 30 m telescope on Pico Veleta, Spain. GISM0-2 will operate Simultaneously in the 1 mm and 2 mm atmospherical windows. The 1 mm channel uses a 32 x 40 TES-based Backshort Under Grid (BUG) bolometer array, the 2 mm channel operates with a 16 x 16 BUG array. The camera utilizes almost the entire full field of view provided by the telescope. The optical design of GISM0-2 was strongly influenced by our experience with the GISMO 2 mm bolometer camera which is successfully operating at the 30m telescope. GISMO is accessible to the astronomical community through the regular IRAM call for proposals.

  16. Dark Energy Camera for Blanco

    Energy Technology Data Exchange (ETDEWEB)

    Binder, Gary A.; /Caltech /SLAC

    2010-08-25

    In order to make accurate measurements of dark energy, a system is needed to monitor the focus and alignment of the Dark Energy Camera (DECam) to be located on the Blanco 4m Telescope for the upcoming Dark Energy Survey. One new approach under development is to fit out-of-focus star images to a point spread function from which information about the focus and tilt of the camera can be obtained. As a first test of a new algorithm using this idea, simulated star images produced from a model of DECam in the optics software Zemax were fitted. Then, real images from the Mosaic II imager currently installed on the Blanco telescope were used to investigate the algorithm's capabilities. A number of problems with the algorithm were found, and more work is needed to understand its limitations and improve its capabilities so it can reliably predict camera alignment and focus.

  17. Perceptual Color Characterization of Cameras

    Directory of Open Access Journals (Sweden)

    Javier Vazquez-Corral

    2014-12-01

    Full Text Available Color camera characterization, mapping outputs from the camera sensors to an independent color space, such as \\(XYZ\\, is an important step in the camera processing pipeline. Until now, this procedure has been primarily solved by using a \\(3 \\times 3\\ matrix obtained via a least-squares optimization. In this paper, we propose to use the spherical sampling method, recently published by Finlayson al., to perform a perceptual color characterization. In particular, we search for the \\(3 \\times 3\\ matrix that minimizes three different perceptual errors, one pixel based and two spatially based. For the pixel-based case, we minimize the CIE \\(\\Delta E\\ error, while for the spatial-based case, we minimize both the S-CIELAB error and the CID error measure. Our results demonstrate an improvement of approximately 3for the \\(\\Delta E\\ error, 7& for the S-CIELAB error and 13% for the CID error measures.

  18. EDICAM (Event Detection Intelligent Camera)

    Energy Technology Data Exchange (ETDEWEB)

    Zoletnik, S. [Wigner RCP RMI, EURATOM Association, Budapest (Hungary); Szabolics, T., E-mail: szabolics.tamas@wigner.mta.hu [Wigner RCP RMI, EURATOM Association, Budapest (Hungary); Kocsis, G.; Szepesi, T.; Dunai, D. [Wigner RCP RMI, EURATOM Association, Budapest (Hungary)

    2013-10-15

    Highlights: ► We present EDICAM's hardware modules. ► We present EDICAM's main design concepts. ► This paper will describe EDICAM firmware architecture. ► Operation principles description. ► Further developments. -- Abstract: A new type of fast framing camera has been developed for fusion applications by the Wigner Research Centre for Physics during the last few years. A new concept was designed for intelligent event driven imaging which is capable of focusing image readout to Regions of Interests (ROIs) where and when predefined events occur. At present these events mean intensity changes and external triggers but in the future more sophisticated methods might also be defined. The camera provides 444 Hz frame rate at full resolution of 1280 × 1024 pixels, but monitoring of smaller ROIs can be done in the 1–116 kHz range even during exposure of the full image. Keeping space limitations and the harsh environment in mind the camera is divided into a small Sensor Module and a processing card interconnected by a fast 10 Gbit optical link. This camera hardware has been used for passive monitoring of the plasma in different devices for example at ASDEX Upgrade and COMPASS with the first version of its firmware. The new firmware and software package is now available and ready for testing the new event processing features. This paper will present the operation principle and features of the Event Detection Intelligent Camera (EDICAM). The device is intended to be the central element in the 10-camera monitoring system of the Wendelstein 7-X stellarator.

  19. Vertex detectors

    International Nuclear Information System (INIS)

    Lueth, V.

    1992-07-01

    The purpose of a vertex detector is to measure position and angles of charged particle tracks to sufficient precision so as to be able to separate tracks originating from decay vertices from those produced at the interaction vertex. Such measurements are interesting because they permit the detection of weakly decaying particles with lifetimes down to 10 -13 s, among them the τ lepton and charm and beauty hadrons. These two lectures are intended to introduce the reader to the different techniques for the detection of secondary vertices that have been developed over the past decades. The first lecture includes a brief introduction to the methods used to detect secondary vertices and to estimate particle lifetimes. It describes the traditional technologies, based on photographic recording in emulsions and on film of bubble chambers, and introduces fast electronic registration of signals derived from scintillating fibers, drift chambers and gaseous micro-strip chambers. The second lecture is devoted to solid state detectors. It begins with a brief introduction into semiconductor devices, and then describes the application of large arrays of strip and pixel diodes for charged particle tracking. These lectures can only serve as an introduction the topic of vertex detectors. Time and space do not allow for an in-depth coverage of many of the interesting aspects of vertex detector design and operation

  20. Smoke detectors

    International Nuclear Information System (INIS)

    Macdonald, E.

    1976-01-01

    A smoke detector is described consisting of a ventilated ionisation chamber having a number of electrodes and containing a radioactive source in the form of a foil supported on the surface of the electrodes. This electrode consists of a plastic material treated with graphite to render it electrically conductive. (U.K.)

  1. Capillary detectors

    International Nuclear Information System (INIS)

    Konijn, J.; Winter, K.; Vilain, P.; Wilquet, G.; Fabre, J.P.; Kozarenko, E.; Kreslo, I.; Goldberg, J.; Hoepfner, K.; Bay, A.; Currat, C.; Koppenburg, P.; Frekers, D.; Wolff, T.; Buontempo, S.; Ereditato, A.; Frenkel, A.; Liberti, B.; Martellotti, G.; Penso, G.; Ekimov, A.; Golovkin, S.; Govorun, V.; Medvedkov, A.; Vasil'chenko, V.

    1998-01-01

    The option for a microvertex detector using glass capillary arrays filled with liquid scintillator is presented. The status of capillary layers development and possible read-out techniques for high rate environment are reported. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  2. Compton camera study for high efficiency SPECT and benchmark with Anger system

    Science.gov (United States)

    Fontana, M.; Dauvergne, D.; Létang, J. M.; Ley, J.-L.; Testa, É.

    2017-12-01

    Single photon emission computed tomography (SPECT) is at present one of the major techniques for non-invasive diagnostics in nuclear medicine. The clinical routine is mostly based on collimated cameras, originally proposed by Hal Anger. Due to the presence of mechanical collimation, detection efficiency and energy acceptance are limited and fixed by the system’s geometrical features. In order to overcome these limitations, the application of Compton cameras for SPECT has been investigated for several years. In this study we compare a commercial SPECT-Anger device, the General Electric HealthCare Infinia system with a High Energy General Purpose (HEGP) collimator, and the Compton camera prototype under development by the French collaboration CLaRyS, through Monte Carlo simulations (GATE—GEANT4 Application for Tomographic Emission—version 7.1 and GEANT4 version 9.6, respectively). Given the possible introduction of new radio-emitters at higher energies intrinsically allowed by the Compton camera detection principle, the two detectors are exposed to point-like sources at increasing primary gamma energies, from actual isotopes already suggested for nuclear medicine applications. The Compton camera prototype is first characterized for SPECT application by studying the main parameters affecting its imaging performance: detector energy resolution and random coincidence rate. The two detector performances are then compared in terms of radial event distribution, detection efficiency and final image, obtained by gamma transmission analysis for the Anger system, and with an iterative List Mode-Maximum Likelihood Expectation Maximization (LM-MLEM) algorithm for the Compton reconstruction. The results show for the Compton camera a detection efficiency increased by a factor larger than an order of magnitude with respect to the Anger camera, associated with an enhanced spatial resolution for energies beyond 500 keV. We discuss the advantages of Compton camera application

  3. Streak cameras and their applications

    International Nuclear Information System (INIS)

    Bernet, J.M.; Imhoff, C.

    1987-01-01

    Over the last several years, development of various measurement techniques in the nanosecond and pico-second range has led to increased reliance on streak cameras. This paper will present the main electronic and optoelectronic performances of the Thomson-CSF TSN 506 cameras and their associated devices used to build an automatic image acquisition and processing system (NORMA). A brief survey of the diversity and the spread of the use of high speed electronic cinematography will be illustrated by a few typical applications [fr

  4. Programmable electronic system for analog and digital gamma cameras modernization

    International Nuclear Information System (INIS)

    Osorio Deliz, J. F.; Diaz Garcia, A.; Arista Omeu, E. J.

    2013-01-01

    At present the use of analog and digital gamma cameras is continuously increasing in developing countries. Many of them still largely rely in old hardware electronics, which in many cases limits their use in actual nuclear medicine diagnostic studies. For this reason worldwide there are different medical equipment manufacturing companies engaged into partial or total Gamma Cameras modernization. Nevertheless in several occasions acquisition prices are not affordable for developing countries. This work describes the basic features of a programmable electronic system that allows improving acquisitions functions and processing of analog and digital gamma cameras. This system is based on an electronic board for the acquisition and digitization of nuclear pulses which have been generated by gamma camera detector. It comprises a hardware interface with PC and the associated software to fully signal processing. Signal shaping and image processing are included. The extensive use of reference tables in the processing and signal imaging software allowed the optimization of the processing speed. Time design and system cost were also decreased. (Author)

  5. Spectral correction algorithm for multispectral CdTe x-ray detectors

    DEFF Research Database (Denmark)

    Christensen, Erik D.; Kehres, Jan; Gu, Yun

    2017-01-01

    Compared to the dual energy scintillator detectors widely used today, pixelated multispectral X-ray detectors show the potential to improve material identification in various radiography and tomography applications used for industrial and security purposes. However, detector effects, such as charge...

  6. ECAT ART - a continuously rotating PET camera: performance characteristics, initial clinical studies, and installation considerations in a nuclear medicine department

    International Nuclear Information System (INIS)

    Bailey, D.L.; Young, H.; Bloomfield, P.M.; Meikle, S.R.; Glass, D.; Myers, M.J.; Spinks, T.J.; Watson, C.C.; Luk, P.; Peters, A.M.; Jones, T.

    1997-01-01

    Advances in image reconstruction techniques have permitted the development of a commercial, rotating, partial ring, fully 3D scanner, the ECAT ART. The system has less than one-half the number of bismuth germanate detectors compared with a full ring scanner with the equivalent field of view, resulting in reduced capital cost. The performance characteristics, implications for installation in a nuclear medicine department, and clinical utility of the scanner are presented in this report. The sensitivity (20 cm diameter x 20 cm long cylindrical phantom, no scatter correction) is 11400 cps.kBq -1 .ml -1 . This compares with 5800 and 40500 cps.kBq -1 .ml -1 in 2D and 3D respectively for the equivalent full ring scanner (ECAT EXACT). With an energy window of 350-650 keV the maximum noise equivalent count (NEC) rate was 27 kcps at a radioactivity concentration of ∝15 kBq .ml -1 in the cylinder. Spatial resolution is ∝6 mm full width at half maximum on axis degrading to just under 8 mm at a distance of 20 cm off axis. Installation and use within the nuclear medicine department does not appreciably increase background levels of radiation on gamma cameras in adjacent rooms and the dose rate to an operator in the same room is 2 μSv .h -1 for a typical fluorine-18 fluorodeoxyglucose ( 18 F-FDG) study with an initial injected activity of 370 MBq. The scanner has been used for clinical imaging with 18 F-FDG for neurological and oncological applications. Its novel use for imaging iron-52 transferrin for localising erythropoietic activity demonstrates its sensitivity and resolution advantages over a conventional dual-headed gamma camera. The ECAT ART provides a viable alternative to conventional full ring PET scanners without compromising the performance required for clinical PET imaging. (orig.). With 9 figs., 3 tabs

  7. Dual waveband compact catadioptric imaging spectrometer

    Science.gov (United States)

    Chrisp, Michael P.

    2012-12-25

    A catadioptric dual waveband imaging spectrometer that covers the visible through short-wave infrared, and the midwave infrared spectral regions, dispersing the visible through shortwave infrared with a zinc selenide grating and midwave infrared with a sapphire prism. The grating and prism are at the cold stop position, enabling the pupil to be split between them. The spectra for both wavebands are focused onto the relevant sections of a single dual waveband detector. Spatial keystone distortion is controlled to less than one tenth of a pixel over the full wavelength range, facilitating the matching of the spectra in the midwave infrared with the shorter wavelength region.

  8. Design studies of a depth encoding large aperture PET camera

    International Nuclear Information System (INIS)

    Moisan, C.; Rogers, J.G.; Buckley, K.R.; Ruth, T.J.; Stazyk, M.W.; Tsang, G.

    1994-10-01

    The feasibility of a wholebody PET tomograph with the capacity to correct for the parallax error induced by the Depth-Of-Interaction of γ-rays is assessed through simulation. The experimental energy, depth, and transverse position resolutions of BGO block detector candidates are the main inputs to a simulation that predicts the point source resolution of the Depth Encoding Large Aperture Camera (DELAC). The results indicate that a measured depth resolution of 7 mm (FWHM) is sufficient to correct a substantial part of the parallax error for a point source at the edge of the Field-Of-View. A search for the block specifications and camera ring radius that would optimize the spatial resolution and its uniformity across the Field-Of-View is also presented. (author). 10 refs., 1 tab., 5 figs

  9. Ion movie camera for particle-beam-fusion experiments

    International Nuclear Information System (INIS)

    Stygar, W.A.; Mix, L.P.; Leeper, R.J.; Maenchen, J.; Wenger, D.F.; Mattson, C.R.; Muron, D.J.

    1992-01-01

    A camera with a 3 ns time resolution and a continuous (>100 ns) record length has been developed to image a 10 12 --10 13 W/cm 2 ion beam for inertial-confinement-fusion experiments. A thin gold Rutherford-scattering foil placed in the path of the beam scatters ions into the camera. The foil is in a near-optimized scattering geometry and reduces the beam intensity∼seven orders of magnitude. The scattered ions are pinhole imaged onto a 2D array of 39 p-i-n diode detectors; outputs are recorded on LeCroy 6880 transient-waveform digitizers. The waveforms are analyzed and combined to produce a 39-pixel movie which can be displayed on an image processor to provide time-resolved horizontal- and vertical-focusing information

  10. Direct cone beam SPECT reconstruction with camera tilt

    International Nuclear Information System (INIS)

    Jianying Li; Jaszczak, R.J.; Greer, K.L.; Coleman, R.E.; Zongjian Cao; Tsui, B.M.W.

    1993-01-01

    A filtered backprojection (FBP) algorithm is derived to perform cone beam (CB) single-photon emission computed tomography (SPECT) reconstruction with camera tilt using circular orbits. This algorithm reconstructs the tilted angle CB projection data directly by incorporating the tilt angle into it. When the tilt angle becomes zero, this algorithm reduces to that of Feldkamp. Experimentally acquired phantom studies using both a two-point source and the three-dimensional Hoffman brain phantom have been performed. The transaxial tilted cone beam brain images and profiles obtained using the new algorithm are compared with those without camera tilt. For those slices which have approximately the same distance from the detector in both tilt and non-tilt set-ups, the two transaxial reconstructions have similar profiles. The two-point source images reconstructed from this new algorithm and the tilted cone beam brain images are also compared with those reconstructed from the existing tilted cone beam algorithm. (author)

  11. Septa design for a prostate specific PET camera

    International Nuclear Information System (INIS)

    Qi, Jinyi; Huber, Jennifer S.; Huesman, Ronald H.; Moses, William W.; Derenzo, Stephen E.; Budinger, Thomas F.

    2003-01-01

    The recent development of new prostate tracers has motivated us to build a low cost PET camera optimized to image the prostate. Coincidence imaging of positron emitters is achieved using a pair of external curved detector banks. The bottom bank is fixed below the patient bed, and the top bank moves upward for patient access and downward for maximum sensitivity. In this paper, we study the design of septa for the prostate camera using Monte Carlo simulations. The system performance is measured by the detectability of a prostate lesion. We have studied 17 septa configurations. The results show that the design of septa has a large impact on the lesion detection at a given activity concentration. Significant differences are also observed between the lesion detectability and the conventional noise equivalent count (NEC) performance, indicating that the NEC is not appropriate for the detection task

  12. Evaluation of efficiency of a semiconductor gamma camera

    CERN Document Server

    Otake, H; Takeuchi, Y

    2002-01-01

    We evaluation basic characteristics of a compact type semiconductor gamma camera (eZ-SCOPE AN) of Cadmium Zinc Telluride (CdZnTe). This new compact gamma camera has 256 semiconductors representing the same number of pixels. Each semiconductor is 2 mm square and is located in 16 lines and rows on the surface of the detector. The specific performance characteristics were evaluated in the study referring to National Electrical Manufactures Association (NEMA) standards; intrinsic energy resolution, intrinsic count rate performance, integral uniformity, system planar sensitivity, system spatial resolution, and noise to the neighboring pixels. The intrinsic energy resolution measured 5.7% as full width half maximum (FWHM). The intrinsic count rate performance ranging from 17 kcps to 1,285 kcps was evaluated, but the highest intrinsic count rate was not observed. Twenty percents count loss was recognized at 1,021 kcps. The integral uniformity was 1.3% with high sensitivity collimator. The system planar sensitivity w...

  13. High-speed holographic camera

    International Nuclear Information System (INIS)

    Novaro, Marc

    The high-speed holographic camera is a disgnostic instrument using holography as an information storing support. It allows us to take 10 holograms, of an object, with exposures times of 1,5ns, separated in time by 1 or 2ns. In order to get these results easily, no mobile part is used in the set-up [fr

  14. The Camera Comes to Court.

    Science.gov (United States)

    Floren, Leola

    After the Lindbergh kidnapping trial in 1935, the American Bar Association sought to eliminate electronic equipment from courtroom proceedings. Eventually, all but two states adopted regulations applying that ban to some extent, and a 1965 Supreme Court decision encouraged the banning of television cameras at trials as well. Currently, some states…

  15. Gamma camera with reflectivity mask

    International Nuclear Information System (INIS)

    Stout, K.J.

    1980-01-01

    In accordance with the present invention there is provided a radiographic camera comprising: a scintillator; a plurality of photodectors positioned to face said scintillator; a plurality of masked regions formed upon a face of said scintillator opposite said photdetectors and positioned coaxially with respective ones of said photodetectors for decreasing the amount of internal reflection of optical photons generated within said scintillator. (auth)

  16. Multiple Sensor Camera for Enhanced Video Capturing

    Science.gov (United States)

    Nagahara, Hajime; Kanki, Yoshinori; Iwai, Yoshio; Yachida, Masahiko

    A resolution of camera has been drastically improved under a current request for high-quality digital images. For example, digital still camera has several mega pixels. Although a video camera has the higher frame-rate, the resolution of a video camera is lower than that of still camera. Thus, the high-resolution is incompatible with the high frame rate of ordinary cameras in market. It is difficult to solve this problem by a single sensor, since it comes from physical limitation of the pixel transfer rate. In this paper, we propose a multi-sensor camera for capturing a resolution and frame-rate enhanced video. Common multi-CCDs camera, such as 3CCD color camera, has same CCD for capturing different spectral information. Our approach is to use different spatio-temporal resolution sensors in a single camera cabinet for capturing higher resolution and frame-rate information separately. We build a prototype camera which can capture high-resolution (2588×1958 pixels, 3.75 fps) and high frame-rate (500×500, 90 fps) videos. We also proposed the calibration method for the camera. As one of the application of the camera, we demonstrate an enhanced video (2128×1952 pixels, 90 fps) generated from the captured videos for showing the utility of the camera.

  17. Applying the neutron scatter camera to treaty verification and warhead monitoring

    International Nuclear Information System (INIS)

    Cooper, Robert Lee; Gerling, Mark; Brennan, James S.; Mascarenhas, Nicholas; Mrowka, Stanley; Marleau, Peter

    2010-01-01

    The neutron scatter camera was originally developed for a range of SNM detection applications. We are now exploring the feasibility of applications in treaty verification and warhead monitoring using experimentation, maximum likelihood estimation method (MLEM), detector optimization, and MCNP-PoliMi simulations.

  18. Defective organification of iodine in an infant demonstrated with 123J and gamma camera

    International Nuclear Information System (INIS)

    Goebel, R.; Leb, G.; Sulzer, M.; Graz Univ.

    1979-01-01

    A defective organification of iodine is demonstrated in a two year old male infant. The availability and a relatively simple radiation detector and storage system (gamma camera and 1600 word memory) gives a reasonable low radiation dose, allows correction for extrathyroid neck activity and obviates problems of collimation. (orig.) [de

  19. Neutron detector

    Science.gov (United States)

    Stephan, Andrew C [Knoxville, TN; Jardret,; Vincent, D [Powell, TN

    2011-04-05

    A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

  20. Ionization detector

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, E E

    1976-02-27

    This invention concerns a fire detection system making use of a beta source. The ionisation detector includes a first and second chamber respectively comprising a first and second electrode, preferably a plate, with a common electrode separating the first and second chamber. Communication is provided between these chambers through a set of orifices and each chamber also has a set of orifices for communication with the ambient atmosphere. One or both chambers can comprise a particle source, preferably beta. The detector also has an adjustable electrode housed in one of the chambers to regulate the voltage between the fixed electrode of this chamber and the common electrode located between the chambers. The electrodes of the structure are connected to a detection circuit that spots a change in the ionisation current when a fire alarm condition arises. The detection circuit of a new type includes a relaxation oscillator with a programmable unijunction transistor and a light emitting diode.

  1. MUST detector

    International Nuclear Information System (INIS)

    Blumenfeld, Y.; Auger, F.; Sauvestre, J.E.

    1999-01-01

    The IPN-Orsay, in collaboration with the SPhN-Saclay and the DPTA Bruyeres, has built an array of 8 telescopes based on Si-strip technology for the study of direct reactions induced by radioactive beams. The detectors are described, along with the compact high density VXI electronics and the stand-alone data acquisition system developed in the laboratory. One telescope was tested using an 40 Ar beam and the measured performances are discussed. (authors)

  2. Radiation detector

    Energy Technology Data Exchange (ETDEWEB)

    Ohata, Shuichi; Takeuchi, Yoji

    1968-10-30

    Herein disclosed is an ionization chamber the airtightness of which can be readily tested. The ionization chamber is characterized in that a small amount of helium gas is filled in the chamber in combination with other ionization gases such as argon gas, xenon gas and the like. Helium leakage from the chamber is measured by a known helium gas sensor in a vacuum vessel. Hence the long term drift of the radiation detector sensitivity may be determined.

  3. Color camera computed tomography imaging spectrometer for improved spatial-spectral image accuracy

    Science.gov (United States)

    Wilson, Daniel W. (Inventor); Bearman, Gregory H. (Inventor); Johnson, William R. (Inventor)

    2011-01-01

    Computed tomography imaging spectrometers ("CTIS"s) having color focal plane array detectors are provided. The color FPA detector may comprise a digital color camera including a digital image sensor, such as a Foveon X3.RTM. digital image sensor or a Bayer color filter mosaic. In another embodiment, the CTIS includes a pattern imposed either directly on the object scene being imaged or at the field stop aperture. The use of a color FPA detector and the pattern improves the accuracy of the captured spatial and spectral information.

  4. A method for correcting the depth-of-interaction blurring in PET cameras

    International Nuclear Information System (INIS)

    Rogers, J.G.

    1993-11-01

    A method is presented for the purpose of correcting PET images for the blurring caused by variations in the depth-of-interaction in position-sensitive gamma ray detectors. In the case of a fine-cut 50x50x30 mm BGO block detector, the method is shown to improve the detector resolution by about 25%, measured in the geometry corresponding to detection at the edge of the field-of-view. Strengths and weaknesses of the method are discussed and its potential usefulness for improving the images of future PET cameras is assessed. (author). 8 refs., 3 figs

  5. KEhD-1 Debye-Sherrar camera with a coordinate proportional counter

    International Nuclear Information System (INIS)

    Ageev, O.I.; Glazova, L.P.; Goganov, D.A.; Rejzis, B.M.; Syrkin, M.G.

    1985-01-01

    An arrangement of the KEhD-1 Debye-Sherrar camera, in which the advantages of a proportional counter are combined with the wide range of simultaneous image recording is described. The camera consists of an X-ray tube unit with the URS-0.1 source, a linear coordinate detector with resistive-capacity coding, a signal transducer and the MK-1 multichannel system for data acquisition and processing based on the ''Uskra-1256'' computer. The counting rate of X-ray pulses is > 5x10 4 s -1 , energy resolution for the CuKsub(α) line constitutes 20%, spatial resolution equals 150 μm, detection efficiency constitutes not less than 64%. The range of the detector displacement varies from -30 deg to +130 deg. The information obtained by means of the camera may be output to a display, a plotter, a numeric printer or a magnetic tape

  6. Development and evaluation of a portable CZT coded aperture gamma-camera

    Energy Technology Data Exchange (ETDEWEB)

    Montemont, G.; Monnet, O.; Stanchina, S.; Maingault, L.; Verger, L. [CEA, LETI, Minatec Campus, Univ. Grenoble Alpes, 38054 Grenoble, (France); Carrel, F.; Lemaire, H.; Schoepff, V. [CEA, LIST, 91191 Gif-sur-Yvette, (France); Ferrand, G.; Lalleman, A.-S. [CEA, DAM, DIF, 91297 Arpajon, (France)

    2015-07-01

    We present the design and the evaluation of a CdZnTe (CZT) based gamma camera using a coded aperture mask. This camera, based on a 8 cm{sup 3} detection module, is small enough to be portable and battery-powered (4 kg weight and 4 W power dissipation). As the detector has spectral capabilities, the gamma camera allows isotope identification and colored imaging, by affecting one color channel to each identified isotope. As all data processing is done at real time, the user can directly observe the outcome of an acquisition and can immediately react to what he sees. We first present the architecture of the system, how the detector works, and its performances. After, we focus on the imaging technique used and its strengths and limitations. Finally, results concerning sensitivity, spatial resolution, field of view and multi-isotope imaging are shown and discussed. (authors)

  7. Development and evaluation of a portable CZT coded aperture gamma-camera

    International Nuclear Information System (INIS)

    Montemont, G.; Monnet, O.; Stanchina, S.; Maingault, L.; Verger, L.; Carrel, F.; Lemaire, H.; Schoepff, V.; Ferrand, G.; Lalleman, A.-S.

    2015-01-01

    We present the design and the evaluation of a CdZnTe (CZT) based gamma camera using a coded aperture mask. This camera, based on a 8 cm 3 detection module, is small enough to be portable and battery-powered (4 kg weight and 4 W power dissipation). As the detector has spectral capabilities, the gamma camera allows isotope identification and colored imaging, by affecting one color channel to each identified isotope. As all data processing is done at real time, the user can directly observe the outcome of an acquisition and can immediately react to what he sees. We first present the architecture of the system, how the detector works, and its performances. After, we focus on the imaging technique used and its strengths and limitations. Finally, results concerning sensitivity, spatial resolution, field of view and multi-isotope imaging are shown and discussed. (authors)

  8. Fixed-focus camera objective for small remote sensing satellites

    Science.gov (United States)

    Topaz, Jeremy M.; Braun, Ofer; Freiman, Dov

    1993-09-01

    An athermalized objective has been designed for a compact, lightweight push-broom camera which is under development at El-Op Ltd. for use in small remote-sensing satellites. The high performance objective has a fixed focus setting, but maintains focus passively over the full range of temperatures encountered in small satellites. The lens is an F/5.0, 320 mm focal length Tessar type, operating over the range 0.5 - 0.9 micrometers . It has a 16 degree(s) field of view and accommodates various state-of-the-art silicon detector arrays. The design and performance of the objective is described in this paper.

  9. Development of the Earth Observation Camera of MIRIS

    Directory of Open Access Journals (Sweden)

    Dae-Hee Lee

    2011-09-01

    Full Text Available We have designed and manufactured the Earth observation camera (EOC of multi-purpose infrared imaging system (MIRIS. MIRIS is a main payload of the STSAT-3, which will be launched in late 2012. The main objective of the EOC is to test the operation of Korean IR technology in space, so we have designed the optical and mechanical system of the EOC to fit the IR detector system. We have assembled the flight model (FM of EOC and performed environment tests successfully. The EOC is now ready to be integrated into the satellite system waiting for operation in space, as planned.

  10. Precise real-time correction of Anger camera deadtime losses

    International Nuclear Information System (INIS)

    Woldeselassie, Tilahun

    2002-01-01

    An earlier paper dealt with modeling of the camera in terms of the resolving times, τ 0 and T, of the paralyzable detector and nonparalyzable computer system, respectively, for the case of a full energy window. A second paper presented a decaying source method for the accurate real-time measurement of these resolving times. The present paper first shows that the detector system can be treated as a single device with a resolving time τ 0 dependent on source distribution. It then discusses camera operation with an energy window, window fraction being f w =R p /R d ≤1, where R d and R p are the detector and pulse-height-analyzer (PHA) outputs, respectively. The detector resolving time is shown to vary with window fraction according to τ 0p =τ 0p /f w , while T is unaffected, so that operation may be paralyzable or nonparalyzable depending on window setting and the ratio k T =T/τ 0 . Regions of interest are described in terms of the ROI fraction, f r =R r /R≤1, and resolving time, τ 0r =τ 0p /f r , where R and R r are the recorded count rates for the field-of-view and the region-of-interest, respectively. As τ 0p and τ 0r are expected to vary with input rate, it is shown that these can be measured in real-time using the decaying source method. It is then shown that camera operation both with f w ≤1 and f r ≤1 can be described by the simple paralyzable equation r=ne -n , where n=N w τ 0p =N r τ 0r and r=R p τ 0p =R r τ 0r , N w , and N r being the input rates within the energy window and the region of interest, respectively. An analytical solution to the paralyzable equation is then presented, which enables the input rates N w =n/τ 0p and N r =n/τ 0r to be obtained correct to better than 0.52% all the way up to the peak response point of the camera

  11. A luminescence imaging system based on a CCD camera

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.; Markey, B.G.

    1997-01-01

    Stimulated luminescence arising from naturally occurring minerals is likely to be spatially heterogeneous. Standard luminescence detection systems are unable to resolve this variability. Several research groups have attempted to use imaging photon detectors, or image intensifiers linked...... to photographic systems, in order to obtain spatially resolved data. However, the former option is extremely expensive and it is difficult to obtain quantitative data from the latter. This paper describes the use of a CCD camera for imaging both thermoluminescence and optically stimulated luminescence. The system...

  12. Counting neutrons with a commercial S-CMOS camera

    Directory of Open Access Journals (Sweden)

    Patrick Van Esch

    2018-01-01

    Full Text Available It is possible to detect individual flashes from thermal neutron impacts in a ZnS scintillator using a CMOS camera looking at the scintillator screen, and off line image processing. Some preliminary results indicated that the efficiency of recognition could be improved by optimizing the light collection and the image processing. We will report on this ongoing work which is a result from the collaboration between ESS Bilbao and the ILL. The main progress to be reported is situated on the level of the on-line treatment of the imaging data. If this technology is to work on a genuine scientific instrument, it is necessary that all the processing happens on line, to avoid the accumulation of large amounts of image data to be analyzed off line. An FPGA-based real-time full-deca mode VME-compatible CameraLink board has been developed at the SCI of the ILL, which is able to manage the data flow from the camera and convert it in a reasonable “neutron impact” data flow like from a usual neutron counting detector. The main challenge of the endeavor is the optical light collection from the scintillator. While the light yield of a ZnS scintillator is a priori rather important, the amount of light collected with a photographic objective is small. Different scintillators and different light collection techniques have been experimented with and results will be shown for different setups improving upon the light recuperation on the camera sensor. Improvements on the algorithm side will also be presented. The algorithms have to be at the same time efficient in their recognition of neutron signals, in their rejection of noise signals (internal and external to the camera but also have to be simple enough to be easily implemented in the FPGA. The path from the idea of detecting individual neutron impacts with a CMOS camera to a practical working instrument detector is challenging, and in this paper we will give an overview of the part of the road that has

  13. Counting neutrons with a commercial S-CMOS camera

    Science.gov (United States)

    Patrick, Van Esch; Paolo, Mutti; Emilio, Ruiz-Martinez; Estefania, Abad Garcia; Marita, Mosconi; Jon, Ortega

    2018-01-01

    It is possible to detect individual flashes from thermal neutron impacts in a ZnS scintillator using a CMOS camera looking at the scintillator screen, and off line image processing. Some preliminary results indicated that the efficiency of recognition could be improved by optimizing the light collection and the image processing. We will report on this ongoing work which is a result from the collaboration between ESS Bilbao and the ILL. The main progress to be reported is situated on the level of the on-line treatment of the imaging data. If this technology is to work on a genuine scientific instrument, it is necessary that all the processing happens on line, to avoid the accumulation of large amounts of image data to be analyzed off line. An FPGA-based real-time full-deca mode VME-compatible CameraLink board has been developed at the SCI of the ILL, which is able to manage the data flow from the camera and convert it in a reasonable "neutron impact" data flow like from a usual neutron counting detector. The main challenge of the endeavor is the optical light collection from the scintillator. While the light yield of a ZnS scintillator is a priori rather important, the amount of light collected with a photographic objective is small. Different scintillators and different light collection techniques have been experimented with and results will be shown for different setups improving upon the light recuperation on the camera sensor. Improvements on the algorithm side will also be presented. The algorithms have to be at the same time efficient in their recognition of neutron signals, in their rejection of noise signals (internal and external to the camera) but also have to be simple enough to be easily implemented in the FPGA. The path from the idea of detecting individual neutron impacts with a CMOS camera to a practical working instrument detector is challenging, and in this paper we will give an overview of the part of the road that has already been walked.

  14. Development of an advanced antineutrino detector for reactor monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Classen, T., E-mail: classen2@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Bernstein, A.; Bowden, N.S. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Cabrera-Palmer, B. [Sandia Livermore National Laboratories, Livermore, CA 94550 (United States); Ho, A.; Jonkmans, G. [Atomic Energy of Canada, Limited, Chalk River Laboratories, Chalk River, ON (Canada); Kogler, L.; Reyna, D. [Sandia Livermore National Laboratories, Livermore, CA 94550 (United States); Sur, B. [Atomic Energy of Canada, Limited, Chalk River Laboratories, Chalk River, ON (Canada)

    2015-01-21

    Here we present the development of a compact antineutrino detector for the purpose of nuclear reactor monitoring, improving upon a previously successful design. This paper will describe the design improvements of the detector which increases the antineutrino detection efficiency threefold over the previous effort. There are two main design improvements over previous generations of detectors for nuclear reactor monitoring: dual-ended optical readout and single volume detection mass. The dual-ended optical readout eliminates the need for fiducialization and increases the uniformity of the detector's optical response. The containment of the detection mass in a single active volume provides more target mass per detector footprint, a key design criteria for operating within a nuclear power plant. This technology could allow for real-time monitoring of the evolution of a nuclear reactor core, independent of reactor operator declarations of fuel inventories, and may be of interest to the safeguards community.

  15. Camera memory study for large space telescope. [charge coupled devices

    Science.gov (United States)

    Hoffman, C. P.; Brewer, J. E.; Brager, E. A.; Farnsworth, D. L.

    1975-01-01

    Specifications were developed for a memory system to be used as the storage media for camera detectors on the large space telescope (LST) satellite. Detectors with limited internal storage time such as intensities charge coupled devices and silicon intensified targets are implied. The general characteristics are reported of different approaches to the memory system with comparisons made within the guidelines set forth for the LST application. Priority ordering of comparisons is on the basis of cost, reliability, power, and physical characteristics. Specific rationales are provided for the rejection of unsuitable memory technologies. A recommended technology was selected and used to establish specifications for a breadboard memory. Procurement scheduling is provided for delivery of system breadboards in 1976, prototypes in 1978, and space qualified units in 1980.

  16. Optomechanical System Development of the AWARE Gigapixel Scale Camera

    Science.gov (United States)

    Son, Hui S.

    Electronic focal plane arrays (FPA) such as CMOS and CCD sensors have dramatically improved to the point that digital cameras have essentially phased out film (except in very niche applications such as hobby photography and cinema). However, the traditional method of mating a single lens assembly to a single detector plane, as required for film cameras, is still the dominant design used in cameras today. The use of electronic sensors and their ability to capture digital signals that can be processed and manipulated post acquisition offers much more freedom of design at system levels and opens up many interesting possibilities for the next generation of computational imaging systems. The AWARE gigapixel scale camera is one such computational imaging system. By utilizing a multiscale optical design, in which a large aperture objective lens is mated with an array of smaller, well corrected relay lenses, we are able to build an optically simple system that is capable of capturing gigapixel scale images via post acquisition stitching of the individual pictures from the array. Properly shaping the array of digital cameras allows us to form an effectively continuous focal surface using off the shelf (OTS) flat sensor technology. This dissertation details developments and physical implementations of the AWARE system architecture. It illustrates the optomechanical design principles and system integration strategies we have developed through the course of the project by summarizing the results of the two design phases for AWARE: AWARE-2 and AWARE-10. These systems represent significant advancements in the pursuit of scalable, commercially viable snapshot gigapixel imaging systems and should serve as a foundation for future development of such systems.

  17. Demonstration of the CDMA-mode CAOS smart camera.

    Science.gov (United States)

    Riza, Nabeel A; Mazhar, Mohsin A

    2017-12-11

    Demonstrated is the code division multiple access (CDMA)-mode coded access optical sensor (CAOS) smart camera suited for bright target scenarios. Deploying a silicon CMOS sensor and a silicon point detector within a digital micro-mirror device (DMD)-based spatially isolating hybrid camera design, this smart imager first engages the DMD starring mode with a controlled factor of 200 high optical attenuation of the scene irradiance to provide a classic unsaturated CMOS sensor-based image for target intelligence gathering. Next, this CMOS sensor provided image data is used to acquire a focused zone more robust un-attenuated true target image using the time-modulated CDMA-mode of the CAOS camera. Using four different bright light test target scenes, successfully demonstrated is a proof-of-concept visible band CAOS smart camera operating in the CDMA-mode using up-to 4096 bits length Walsh design CAOS pixel codes with a maximum 10 KHz code bit rate giving a 0.4096 seconds CAOS frame acquisition time. A 16-bit analog-to-digital converter (ADC) with time domain correlation digital signal processing (DSP) generates the CDMA-mode images with a 3600 CAOS pixel count and a best spatial resolution of one micro-mirror square pixel size of 13.68 μm side. The CDMA-mode of the CAOS smart camera is suited for applications where robust high dynamic range (DR) imaging is needed for un-attenuated un-spoiled bright light spectrally diverse targets.

  18. Dual-readout calorimetry with scintillating crystals

    International Nuclear Information System (INIS)

    Pinci, D

    2009-01-01

    The dual-readout approach, which allows an event-by-event measurement of the electromagnetic shower fraction, was originally demonstrated with the DREAM sampling calorimeter. This approach can be extended to homogeneous detectors like crystals if Cherenkov and scintillation light can be separated. In this paper we present several methods we developed for distinguishing the two components in PWO and BGO based calorimeters and the results obtained.

  19. Architectural Design Document for Camera Models

    DEFF Research Database (Denmark)

    Thuesen, Gøsta

    1998-01-01

    Architecture of camera simulator models and data interface for the Maneuvering of Inspection/Servicing Vehicle (MIV) study.......Architecture of camera simulator models and data interface for the Maneuvering of Inspection/Servicing Vehicle (MIV) study....

  20. Selecting a digital camera for telemedicine.

    Science.gov (United States)

    Patricoski, Chris; Ferguson, A Stewart

    2009-06-01

    The digital camera is an essential component of store-and-forward telemedicine (electronic consultation). There are numerous makes and models of digital cameras on the market, and selecting a suitable consumer-grade camera can be complicated. Evaluation of digital cameras includes investigating the features and analyzing image quality. Important features include the camera settings, ease of use, macro capabilities, method of image transfer, and power recharging. Consideration needs to be given to image quality, especially as it relates to color (skin tones) and detail. It is important to know the level of the photographer and the intended application. The goal is to match the characteristics of the camera with the telemedicine program requirements. In the end, selecting a digital camera is a combination of qualitative (subjective) and quantitative (objective) analysis. For the telemedicine program in Alaska in 2008, the camera evaluation and decision process resulted in a specific selection based on the criteria developed for our environment.